CA2294970C - Ethernet transport facility over digital subscriber lines - Google Patents
Ethernet transport facility over digital subscriber lines Download PDFInfo
- Publication number
- CA2294970C CA2294970C CA002294970A CA2294970A CA2294970C CA 2294970 C CA2294970 C CA 2294970C CA 002294970 A CA002294970 A CA 002294970A CA 2294970 A CA2294970 A CA 2294970A CA 2294970 C CA2294970 C CA 2294970C
- Authority
- CA
- Canada
- Prior art keywords
- transmission path
- data
- ethernet
- facility
- operative
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
- H04M11/062—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/46—Interconnection of networks
- H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
- H04L12/4612—LAN interconnection over narrowband networks, e.g. N-ISDN, PSTN, X.25
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/64—Hybrid switching systems
- H04L12/6418—Hybrid transport
Abstract
A facility transport system for transporting Ethernet over digital subscriber lines. The system, termed 10BaseS, is capable of transmitting of 10 Mbps Ethernet over existing copper infrastructure. The system utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport Ethernet frame data and utilizes splitter means (22) to separate both the downstream and upstream channels from POST signals.
Description
ETHERNET TRANSPORT FACILITY OVER DIGITAL SUBSCRIBER LINES
FIELD OF THE INVENTION
The present invention relates generally to telecommunication systems and more particularly relates to a system for transporting Ethernet over digital subscriber Lines.
s BACKGROUND OF THE INVENTION
There is a growing need among both individuals and enterprises for access to a commonly available, cost effective network that provides speedy, reliable services.
There is high demand for a high-speed data network, one with enough bandwidth to enable complex two-way communications. Such an application is possible today if, for ~o example, you have access to a university or a corporation with sufficient finances to build this type of network. But for the average home computer user or small business, access to high speed data networks is expensive or simply impossible.
Telephone companies are therefore eager to deliver broadband services to meet this current explosion in demand.
t s One of the problems is that millions of personal computers have found their place in the home market. Today, PCs can be found in approximately 35% of all United States households and a full 50% of United States teenagers own computers.
Virtually every PC sold today is equipped with a modem, enabling communication with the outside world via commercial data networks and the Internet. Currently, people use their 2o PCs to send and receive e-mail, to access online services, to participate in electronic commerce and to browse the Internet. The popularity of the Internet is such that there are an estimated 30 million users around the globe. These figures indicate that in the past few years the persona( computer has fueled a dramatic increase in data communications and the corresponding demands on the data networks that carry the 2s traffic.
The Internet serves as a good example of the increased demands that have been placed on data networks. At first, Internet access consisted of text only data transfers.
Recently, with the popularity of the World Wide Web (WWW) and the development of Internet browsers such as Mosaic, Netscape Navigator or Microsoft Explorer, the use of graphics has surged on the Internet. While graphics make for a much more interesting way to view information as opposed to plain text, bandwidth consumption is significantly more. A simple background picture with accompanying text requires s approximately 10 times the bandwidth needed by text alone. Because of the increased requirement for bandwidth, activities such as browsing home pages or downloading graphics files can take a frustratingly long period of time. Considering that the graphics rich World Wide Web accounts for more than one quarter of all Internet traffic, it is easy to see why the demand for bandwidth has outpaced the supply. In addition, the creative io community is pushing the envelope by offering audio and full motion video on numerous sites to differentiate themselves from the millions of other sites competing for maximum user hits.
As use of the Internet and online services continues to spread, so does the use of more complex applications, such as interactive video games, telecommuting, business to is business communications and videoconferenceing. These complex applications place severe strains on data networks because of the intensive bandwidth required to deliver data-rich transmissions. For example, a telecommuter who requires computer aided design (CAD) software to be transported over the data network requires a high-bandwidth data pipeline because of the significant size of CAD files.
Similarly, a 2o business to business transaction in which large database files containing thousands of customer records are exchanged also consumes large amounts of bandwidth. The same is true for users seeking entertainment value from sites offering high quality video and audio. The lack of available bandwidth in today's data networks is the primary barrier preventing many applications from entering mainstream use. Just as processing power 2s limited the effectiveness of early PCs, bandwidth constraints currently limit the capabilities of today's modem user.
Most computer modem users access data through the standard telephone network, known as plain old telephone service (POTS). Equipped with today's speediest modems, dial up modems on a POTS network can access data at a rate of 28.8, 33.6 or 30 56 Kbps. Dial up modem transmission rates have increased significantly over the last few years, but POTS throughput is ultimately limited to 64 Kbps. While this rate may
FIELD OF THE INVENTION
The present invention relates generally to telecommunication systems and more particularly relates to a system for transporting Ethernet over digital subscriber Lines.
s BACKGROUND OF THE INVENTION
There is a growing need among both individuals and enterprises for access to a commonly available, cost effective network that provides speedy, reliable services.
There is high demand for a high-speed data network, one with enough bandwidth to enable complex two-way communications. Such an application is possible today if, for ~o example, you have access to a university or a corporation with sufficient finances to build this type of network. But for the average home computer user or small business, access to high speed data networks is expensive or simply impossible.
Telephone companies are therefore eager to deliver broadband services to meet this current explosion in demand.
t s One of the problems is that millions of personal computers have found their place in the home market. Today, PCs can be found in approximately 35% of all United States households and a full 50% of United States teenagers own computers.
Virtually every PC sold today is equipped with a modem, enabling communication with the outside world via commercial data networks and the Internet. Currently, people use their 2o PCs to send and receive e-mail, to access online services, to participate in electronic commerce and to browse the Internet. The popularity of the Internet is such that there are an estimated 30 million users around the globe. These figures indicate that in the past few years the persona( computer has fueled a dramatic increase in data communications and the corresponding demands on the data networks that carry the 2s traffic.
The Internet serves as a good example of the increased demands that have been placed on data networks. At first, Internet access consisted of text only data transfers.
Recently, with the popularity of the World Wide Web (WWW) and the development of Internet browsers such as Mosaic, Netscape Navigator or Microsoft Explorer, the use of graphics has surged on the Internet. While graphics make for a much more interesting way to view information as opposed to plain text, bandwidth consumption is significantly more. A simple background picture with accompanying text requires s approximately 10 times the bandwidth needed by text alone. Because of the increased requirement for bandwidth, activities such as browsing home pages or downloading graphics files can take a frustratingly long period of time. Considering that the graphics rich World Wide Web accounts for more than one quarter of all Internet traffic, it is easy to see why the demand for bandwidth has outpaced the supply. In addition, the creative io community is pushing the envelope by offering audio and full motion video on numerous sites to differentiate themselves from the millions of other sites competing for maximum user hits.
As use of the Internet and online services continues to spread, so does the use of more complex applications, such as interactive video games, telecommuting, business to is business communications and videoconferenceing. These complex applications place severe strains on data networks because of the intensive bandwidth required to deliver data-rich transmissions. For example, a telecommuter who requires computer aided design (CAD) software to be transported over the data network requires a high-bandwidth data pipeline because of the significant size of CAD files.
Similarly, a 2o business to business transaction in which large database files containing thousands of customer records are exchanged also consumes large amounts of bandwidth. The same is true for users seeking entertainment value from sites offering high quality video and audio. The lack of available bandwidth in today's data networks is the primary barrier preventing many applications from entering mainstream use. Just as processing power 2s limited the effectiveness of early PCs, bandwidth constraints currently limit the capabilities of today's modem user.
Most computer modem users access data through the standard telephone network, known as plain old telephone service (POTS). Equipped with today's speediest modems, dial up modems on a POTS network can access data at a rate of 28.8, 33.6 or 30 56 Kbps. Dial up modem transmission rates have increased significantly over the last few years, but POTS throughput is ultimately limited to 64 Kbps. While this rate may
2 be acceptable for some limited applications like e-mail, it is a serious bottleneck for more complex transactions, such as telecommuting, videoconferenceing or full-motion video viewing. To illustrate, full motion video compressed, using the Motion Picture Entertainment Group (MPEG)-2 standard requires a data stream of approximately s Mbps, or roughly 208 times the throughput of a 28.8 Kbps modem. Thus, using today's dial up modems, it would take more than 17 days to capture two hours of video.
As bandwidth demands continue to grow, providers search for better ways to offer high speed data access. Further complicating the problem is the need to deliver all these complex services at an affordable price.
~o Today's most popular data access method is POTS. But as discussed previously, POTS is limited when it comes to large data transfers. An alternative to POTS
currently available is Integrated Services Digital Network (ISDN). In the past few years, ISDN
- has gained momentum as a high-speed option to POTS. ISDN expands data throughput to 128 Kbps, both from the network to the home and from the home back to the network, is and can be technically made available throughout much of the United States.
Similar to POTS, ISDN is a dedicated service, meaning that the user has sole access to the line preventing other ISDN users from sharing the same bandwidth. ISDN is considered an affordable alternative, and in general, ISDN is a much better solution for applications such as Web browsing and basic telecommuting. However, like POTS, it severely limits 2o applications such as telecommuting with CAD files and full-motion video viewing. The latter requires roughly 39 times the throughput than that provided by ISDN.
Multichannel multipoint distribution service (MMDS), a terrestrial microwave wireless delivery system, and direct broadcast satellite (DBS), such as DirecTv and USSB, are wireless networks. They both deliver high bandwidth data steams to the home, referred 2s to as downstream data, but neither has a return channel through which data is sent back over the network, referred to as upstream data. Although it is a relatively affordable system to deploy for broadcast applications, because it requires no cable wires to be laid, it falls short in interactive access. In order to use a wireless system for something as basic as e-mail, an alternate technology such as a telephone line must be used for the 3o upstream communications.
As bandwidth demands continue to grow, providers search for better ways to offer high speed data access. Further complicating the problem is the need to deliver all these complex services at an affordable price.
~o Today's most popular data access method is POTS. But as discussed previously, POTS is limited when it comes to large data transfers. An alternative to POTS
currently available is Integrated Services Digital Network (ISDN). In the past few years, ISDN
- has gained momentum as a high-speed option to POTS. ISDN expands data throughput to 128 Kbps, both from the network to the home and from the home back to the network, is and can be technically made available throughout much of the United States.
Similar to POTS, ISDN is a dedicated service, meaning that the user has sole access to the line preventing other ISDN users from sharing the same bandwidth. ISDN is considered an affordable alternative, and in general, ISDN is a much better solution for applications such as Web browsing and basic telecommuting. However, like POTS, it severely limits 2o applications such as telecommuting with CAD files and full-motion video viewing. The latter requires roughly 39 times the throughput than that provided by ISDN.
Multichannel multipoint distribution service (MMDS), a terrestrial microwave wireless delivery system, and direct broadcast satellite (DBS), such as DirecTv and USSB, are wireless networks. They both deliver high bandwidth data steams to the home, referred 2s to as downstream data, but neither has a return channel through which data is sent back over the network, referred to as upstream data. Although it is a relatively affordable system to deploy for broadcast applications, because it requires no cable wires to be laid, it falls short in interactive access. In order to use a wireless system for something as basic as e-mail, an alternate technology such as a telephone line must be used for the 3o upstream communications.
3 Another network delivery system is asymmetric digital subscriber line (ADSL).
Offering a downstream capacity of 6 Mbps or more to the home, ADSL has the downstream capacity to handle the most complex data transfers, such as full motion video, as well as upstream capacity of at least 500 Kbps. However, due to its limitation s of downstream bandwidth capacity, it essentially is a single service platform. Also, since it has to overcome the challenge of reusing several thousand feet of twisted pair wiring, the electronics required at each end of the cable are complex, and therefore currently very expensive.
Hybrid fiber coax (HFC), a network solution offered by telephone and cable ~ o companies, is yet another option for delivering high bandwidth to consumers known in the art. However, HFC has limitations. HFC networks provide a downstream capacity of approximately 30 Mbps, which can be shared by up to 500 users. Upstream - bandwidth is approximately 5 Mbps and also is shared. A disadvantage with HFC is that shared bandwidth and limited upstream capacity become serious bottlenecks when ~ s hundreds of users are sending and receiving data on the network, with service increasingly impaired as each user tries to access the network.
It is a current trend among telephone companies around the world to include existing twisted pair copper loops in their next generation broadband access networks.
Hybrid Fiber Coax (HFC), a shared access medium well suited to analog and digital 2o broadcast, comes up short when utilized to carry voice telephony, interactive video and high speed data communications at the same time.
Fiber to the home (FTTH) is still prohibitively expensive in the marketplace which is soon to be driven by competition rather than costs. An alternative is a combination of fiber cables feeding neighborhood Optical Network Units (ONUS) and 2s last leg premises connections by existing or new copper. This topology, which can be called fiber to the neighborhood (FTTN), encompasses fiber to the curb (FTTC) with short drops and fiber to the basement (FTTB), serving tall buildings with vertical drops.
One of the enabling technologies for FT'IN is very high rate digital subscriber line (VDSL). VDSL is an emerging standard that is currently undergoing discussion in 3o ANSI and ETSI committees. The system transmits high speed data over short reaches of
Offering a downstream capacity of 6 Mbps or more to the home, ADSL has the downstream capacity to handle the most complex data transfers, such as full motion video, as well as upstream capacity of at least 500 Kbps. However, due to its limitation s of downstream bandwidth capacity, it essentially is a single service platform. Also, since it has to overcome the challenge of reusing several thousand feet of twisted pair wiring, the electronics required at each end of the cable are complex, and therefore currently very expensive.
Hybrid fiber coax (HFC), a network solution offered by telephone and cable ~ o companies, is yet another option for delivering high bandwidth to consumers known in the art. However, HFC has limitations. HFC networks provide a downstream capacity of approximately 30 Mbps, which can be shared by up to 500 users. Upstream - bandwidth is approximately 5 Mbps and also is shared. A disadvantage with HFC is that shared bandwidth and limited upstream capacity become serious bottlenecks when ~ s hundreds of users are sending and receiving data on the network, with service increasingly impaired as each user tries to access the network.
It is a current trend among telephone companies around the world to include existing twisted pair copper loops in their next generation broadband access networks.
Hybrid Fiber Coax (HFC), a shared access medium well suited to analog and digital 2o broadcast, comes up short when utilized to carry voice telephony, interactive video and high speed data communications at the same time.
Fiber to the home (FTTH) is still prohibitively expensive in the marketplace which is soon to be driven by competition rather than costs. An alternative is a combination of fiber cables feeding neighborhood Optical Network Units (ONUS) and 2s last leg premises connections by existing or new copper. This topology, which can be called fiber to the neighborhood (FTTN), encompasses fiber to the curb (FTTC) with short drops and fiber to the basement (FTTB), serving tall buildings with vertical drops.
One of the enabling technologies for FT'IN is very high rate digital subscriber line (VDSL). VDSL is an emerging standard that is currently undergoing discussion in 3o ANSI and ETSI committees. The system transmits high speed data over short reaches of
4 twisted pair copper telephone lines. with a range of speeds depending upon actual line length.
StJN~IARY OF THE INVENTION
The presents inven>~~ on p.rov iW -.s ;~ facility transport system for transporting Et:hernet over digital subscriber lines. The system, termed lOBaseS, is cad>able of transmitting of 10 Mbps Ethernet over existing cc>pper infrastructure. The system utilizes carrierlcass ampl.:ituc:le modulation/phase modulation (CAP), a version of suppressed carrier quadrature amplitude modulation :;QAN1) . The 1JL~~:~se::~ transport facility can deliver symmet.ri,cal d~:~ta at appro~: imately 13 Mbps (net 10 Mbps) over the unscr~sen~ad, t:wist.ec:~ pair telephone wires orz_ginally intended for k:~anc9widt~hs cs.f' between 3C)0 Hz and 3.4 KHz. The system utilize. frequencyy~ d:v:isiorz multiplexing (FDM) to separate downstream crZar~rat2l;~, from upstream channels.
FDM is also used to separate both the downstream and the upstream channels from i-e0'1:'S signa.l.s. The downstream and upstream dot=a ch<~nnels ar:_v .~e~~ara~ted in ~r.equenc:y =rom bands used for POTS and ISDN, er:abl_irng ser~:ic:e providers to overlay lOBaseS on existing servic:~es .
The lOBaseS system has appl.i..cations in the small office/home office (SOHO) market and can be installed in industrial areas or business d.str:i.~_-ts where most of the copper infrastructure is of shorter distances. The small office/home office market. ryas ar:eat.:l.y r~eveloped in recent years and is eagerly waiting for hAt~7 extension solutions. The need for connecting between ~;evera.l bu.-ldings of the same company or between headquarters to brancaes, dictates either usi-ng a leased 1-one such .zs TllT3 wh:i~.h :s very expensive or a POTS/ISDN modern which is ~_Tery ~s:Lcw. TL:e lOBaseS system of the present invention cars beapplied tc: tYuese mark>ets while achieving better price ~:o,~rf orz~lar",:e -or kooth the telephone company and the end user.
E;
There is t~herefcre provided in accordance with the present invention a po:i.nt t~.~ point fa=~ci 7 ity transport system for the transpc>rt of ~t.he~rnet fr<ume data over a copper infrastructure <:onnectir,.c1 <a c:entra:I o:f:fice f_<~ci_Lity to a customer premise, c:ompri~;ir_g a downstream transmission pat=h for transporting Ethernet frame data transmitted fr,>m the .-ent_ral. office faci~.ity destined to the c:u~,~..cmer pren~:i.sE~, said downstream transmission path operat:ive~ t=.o sirnult,.rneously carry both voice and Ethernet data s._gna~~s;
an upstream transmisaion path f:_,r transporting Ethernet frame data transmitted fr~:>m the <-:ust~>mer p.rernise destined to the central office facilil.:.y, sai~a up:~tream transmission path operative to sirnultaneou>:Ly car_ry L,~c~t:rn voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetria:al i_ra data transmission capacity, the Et.hernet t:ransmissi.on capacity of said downstream transmission path being s~.abst,_~ntially the same as the Ethernet ~raosmis:=~.i.on ca~~~acit.y of said upstream transmission path;
first modem means lo;~ated at. t=he ~~~entral off ice facility and coupled to one end of said down:~~i..re,~~m t:ran~~mission path and one end of said upstream tr°ansmission path;
second modem means Lc>cated at ttie c-:ustc>mer premise and coupled to the other end c:f ,raid downstream transmissicn path and the other end of said ~zp:~trearr; t: ransrnission path; and wherein said first modem mear::~ aruci said second modem means are operative to plaa:e onto and reca~ive from the copper infrastructure data frames encapsulating said Ethernet frame data.
Preferably, further, the downst: ream transmission path uti:li~zes carr:ieri_est~ airnplit;:ude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport the Et. hernet. frame data from the central office facility to the c.zstc:>me:r premi.:>c, and t:he upstream transmission path utiii:_~.f:es cvarri.erless amplitu~_te modulation phase modulation/quadratu~:e amplitude modulation (CAP/QAM) to transport the Et.hernet frame data fr;~m the customer premise to the central office fa~:, l l ity.
Preferably, in addit.i_c-gin, t:he f-:~:~.~t, modem means and t:he second modem rnean;s f~,rtr,c.r cc:~mpr_ s~e t ransm:i_tte:r means for coupling to the copper infr~:~structure, t;ne transmitter means operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto the cod>per infrastructure, and receiver means for couplng to tr~~~ cc:~sper infrast:ru,:ture, the receiver means operatiUe. t.c de-enca:osm late received data frames into Ethernet frame data anal to generate a receive data signal therE:from.
There is also provided iru ac,c:ordar~~e with the present invention a pov.~n". to pc:~:irnt f ac;i_l itvY~ t:ra.r~,~i:~ori~ syt>tem for the transport of Etherrnet fr<~mE.~ ;.iate;~ :~,~rud ~~.ain old telephone service (POTS) over a copper infrastr~.icture connecting a central office facility to a customer premise, comprising:
a downstream transmissic>n path c>r trans~>ori~,yng Ethernet frame data and POI'S tr~3nsrnit.ted from the central office facility destined to the casn::orner prerr~isc;
an upstream transmission ~:~ath for transporting Ethernet frame data and POTS transmitted from the customer premise destined to the central c:~f.t=ice far~~ili.t:y;
said downstream i::ra°csrr~iss~ic:~n I:.:~th and said upstream transmission path being syrnme~rical in data transmissions capacity, the Ethernet transmission: capacity of said downstream transmission path being sul~st:~:,ntially the same as the Ethernet transmissi.ori capac.-~.y of said upstream transmission path;
first modem means loa~ated at: thE=' central office facility and coupled to one end ot_ raid ciowr:stream transmission path and one end of said upstr.~arr tr.ar~5mi:si<.opath;
second modem means : oc:.~t:c.d at t he ustumen premise and coupled t~o the other- encl c f said down:;TrE-:am transmission path and the other end of said upstream tuansrr~ission path;
first sputter means coupled to sa i d f i rst modem means and to said copper i.nf rastr~.,act.ure, ~s~:a i d first. sol fitter means for combining and split: t ir~g Et:r~~er.ru.--.t. r~::at ~ si_gna 1_s with voi ce POTS voice signals;
second spl_it:ter means coupled to said second modem means and to said copper i.nfrast:ru-cture, s~:3:id ~:econd sp.litter means for combining and splii_ti:og Ether_net data signals with voice POTS voice signa's; and wherein said first modem means an,:x sand second modem means are operative to place orlt~.~_-~ arrcl receive from the copper infrastructure d~rta packet:.s ~~nc.;ap;ul.~:tina said Ethernet frame data.
In addition, there s prov.i.ded in accordance with the present invent:i.on a po:.nt to pc;int ra~cv_l i.t.y t ransport system fcr the transports of L~:t.fmrrrfvt fr_~rc~c zata over a copper infrastructure connecting a central. office facility to a customer premise, comprising;
a downstrearu transmission path for trans:port:ing Ethernet frame data transmitted from tree :entr.:a~~ office facility destined to the customer prern.i.se, said downstream transmission path operar_a..vE:- to s.i.mr.rltaneously carry both voice and Ethernet data sigm:~ls;
an upstream transrr:ission path for ~ransport:ing Ethernet frame data transmitted from thu uust~>.rnen premise destined to the central- offi<:e faci 1i t:.y, said l.zp.~?-re-tm tr_ansmission path 8a operative to simultaneous:l.y ~:_arry both voice and Ethernet dat=a signals;
said downs-ream t.r<<nsmi_ssion math and said upstream transmission pavr~ being s~mnuet,rm~~-: in data transmission capacity, the Etherne'~ ;=ransrniss i c>n capacity of said downstream transmission ~oat~ra bceirug substantially tree same as the Ethernet transmission capacity of said upstream transmission path;
switch means located at the central office facility and coupled to one end o.f s.=aid downstream transmis:>ion path and one end of said upstream ::ransmissic3r; path;
a network element l.e:,cated at. toe c ustomer premise and coupled to the other errd of said c~OWrzst:re:am transmission path and the other Enc. of said ~..rp5tr~eam tr~<=arnsrr.ission -oath; and wherein sai:~ swit;_:ru rnear::, arud s~~id network element are operative to place c~nt~> and receive: from true copper infrastructure data frames encapsulating said Ethernet frame data.
There is also prc>vided in accorcan~:e with the present invention a transport sy>tem f-ot_ t:rw, t.z ansport of Ethernet frame data and plain c>id telephone sfervice (POTS) voice signals over a copper :i..rnfrasl.ru~ltu.re cormectinc~ a central office facility t:o a customer- prerr:ise, comprising:
a private branch Exchange (PBX) ~~:oupled to said central office facility and operas ive to receive and transmit voice signals between said ~~t='r,tra.l. of tv: ~~~ i ac~i lity and said customer premise;
a local area network (L~~N) coozp:led t.o said central office facility and operative to receive and transmit Ethernet data signals betwe~=n said ~::entral. office facility and said customer premise;
~3 b a first plurality c:f modems coupled to said LAN and operative to convert Ethernet cia~.a~ ..ignals into analog lOBaseS signals;
a first plura:~its~ of sp:lit.ters coupled to said first plurality of mod~rms and okoerat.ive to ~~.ombine and split analog lOBaseS signals and PO'CS voice signals such that the output of each spl.itter ~.s a comkeined ~.~c:;.i_ce :vnd data. signal;
a second plurality c:~f spli..t..t:er:~ cc: upl_ec~ to said first plurality of modems and c:~perative t:.~ r_ec:eive combined voice and data signal's and split: in into analog lOB,aseS signals and POTS voice signals;
a second plural.it=y ~::~f modems <~our~ied to said second plurality of spl~_t:ters and operat:..~;e to convert analog 1C)BaseS signals to ~;thern~et chat=a sigrvals for transmission to one or more networ>,: elements;
a plurality of vo-Lce tc=1_ephc~ne de~T:aces coupled to said second plurality of spii.ttez:vs, sack ~,l.uralit:y of voice telephone device's coperativ;a ~~o comznun::.c;ata with said PBX;
wherein Fth~~rnet daaaa is transmitted in both directions between said LAN and said plurality :~f nE~twork elements at a symmetrical data rate; anti wherein Ethernet data and POTS voice signals are combined and vimul.tane-,~u~:~ly trarusmi_ti,:.ed between said first plurality of L.plitters and sa:i.~~ second plurality of splatters.
8 c:
WO 98/54856 PCT/~L98/00242 BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
Fig. 1 is a high level block diagram illustrating the lOBaseS transport facility of s the present invention as applied to a sample telephony application;
Fig. 2 is a high level block diagram illustrating a sample customer premises network utilizing the 1 OBaseS transport facility of the present invention;
Fig. 3 is a high level block illustrating an optical network unit connected to multiple customer premises via the I OBaseS transport facility;
o Fig. 4 is a high level block diagram illustrating the transmit portion of the l OBaseS modem of the present invention; and Fig. 5A and SB are high level block diagrams illustrating the receive portion of the l OBaseS modem of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Notation Used Throughout The following notation is used throughout this document.
'Perm Definition ADSL Asymmetric Digital Subscriber Line AGC Automatic Gain Control ANSI American National Standards Institute BER Bit Error Rate CAD Computer Aided Design CAP Carrierless Amplitude Modulation/Phase Modulation DBS Direct Broadcast Satellite ETSI European Telecommunications Standards Institute FDM Frequency Division Multiplexing FEC Forward Error Correction FEXT Far End Crosstalk FIFO First In First Out FTTB Fiber to the Building FTTC Fiber to the Curb FTTCab Fiber to the Cabinet FTTEx Fiber to the Exchange FTTH Fiber to the Home FTTN Fiber to the Node HFC Hybrid Fiber Coax ISDN Integrated Services Digital Network ISP Internet Service Provider LAN Local Area Network MMDS Multichannel Multipoint Distribution Service MPEG Motion Picture Entertainment Group NEXT Near End Crosstalk NIC Network Interface Card NTP Network Termination Point ONU Optical Network Unit PBX Private Branch Exchange PC Personal Computer PLL Phase Lock Loop POTS Plain Old Telephone Service PSD Power Spectral Density QAM Quadrature Amplitude Modulation QoS Quality of Service RFI Radio Frequency Interference SNMP Simple Network Management Protocol SNR Signal to Noise Ratio SOHO Small Office/Home Office TDMA Time Division Multiple Access VCXO Voltage Controlled Crystal Oscillator VDSL Very High Speed Digital Subscriber Line WAN Wide Area Network WWW World Wide Web General Description The present invention is a facility transport system for transporting Ethernet over digital subscriber lines. The system is referred to as lOBaseS and is capable of s transmitting of IO Mbps Ethernet over existing copper infrastructure. The system utilizes carrierless amplitude modulation/phase modulation (CAP) which is a version of suppressed carrier quadrature amplitude modulation (QAM). QAM is the most commonly used form of high speed modulation over voice telephone lines. The system also utilizes frequency division multiplexing (FDM) to separate downstream channels to from upstream channels. In addition, FDM is also used to separate both the downstream and the upstream channels from POTS and ISDN signals. A substantial distance in frequency is maintained between the lowest data channel and POTS frequencies to permit the use of very simple and cost effective POTS splitters, which are actually splitters/combiners. The upstream channel is placed above the downstream channel in is frequency. The downstream and upstream data channels are separated in frequency from bands used for POTS and ISDN, enabling service providers to overlay lOBaseS on existing services.
The lOBaseS system of the present invention combines copper access transmission technology of Ethernet based services with Quality of Service (QoS) 2o guaranteed by the SRVP protocol and is capable of being fully managed through an SNMP agent. The lOBaseS transport facility can deliver symmetrical data at 12.96 Mbps (net 10 Mbps) over the unscreened, twisted pair telephone wires originally intended for bandwidths of between 300 Hz and 3.4 KHz. The invention uses QAM
modulation and blind equalization to achieve a high transmission speed over existing 2s copper infrastructure. In addition, the system is able to cope with several sources of noise such as impulse noise, e.g., POTS transients, radio frequency interference (RFI) noise and crosstalk noise, i.e., both near end crosstalk (NEXT) and far end crosstalk (FEXT). In terms of RF emissions, the system can operate using underground cabling as well as overhead distribution cabling.
s Both the LAN, i.e., Ethernet frames, and POTS services, i.e., voice, may be transmitted over a common optical access network before final distribution over a copper distribution network. Alternatively, in the case where LAN services are provided by an overlay network, an Optical Network Unit (ONU) is co-located with an existing copper network distribution point where the LAN and POTS services are combined for io transmission over the existing copper distribution network.
In one installation application of the invention, lOBaseS transmission would be used on shorter exchange lines when the switch or ONU is located in a serving exchange - building.
The switch or ONU may be sited in different locations forming different is architectures for a hybrid optical network. Some of these architectures include: fiber to the cabinet (FTTCab), fiber to the curb (FTTC), fiber to the node (FTTN), fiber to the building (FTTB) and fiber to the exchange (FTTEx).
The lOBaseS transport facility of the present invention supports both LAN and POTS services sharing the same copper distribution cable. The POTS and the LAN
2o services are separated close to the point where the combined signals enter the customer premises. This is achieved by a POTS sputter filter. i.e., splitter/combiner filter, which may or may not be part of the network termination (NT). The lOBaseS system is a point to point transmission system even though the core modem is a blind modem which is able to support point to multipoint communications. The network termination interface 2s at the customer premises can be the widely used lOBaseT R.I-45 or lOBase2 BNC
interface. The customer can hook up any common l OBaseT or l OBase2 equipment, such as an Ethernet switch or hub, or any product that has an Ethernet network interface card (NIC). The network interface unit will respond to test and management messages originated by any SNMP network management system.
The system supports two latency modes that can be modified by software or through the network management: with an interieaver resulting in a latency of less than 100 msec; without an interleaver resulting in a latency of less than 1.5 msec.
lOBaseS Applications A high level block diagram illustrating the lOBaseS transport facility of the present invention as applied to a sample telephony application is shown in Figure 1. The public switched telephone network (PSTN) 110 is shown with one central office (CO) switch 114 coupled to Internet service provider (ISP) 136. The ISP comprises an access switch 138 which is shown coupled to two network elements 140, 142. Another central ~o office switch 112 is shown connected by a fiber link to the access switch 116.
The access switch 116 is shown connected to two access switches 118, 134 via 1 OBaseS connections. The two access switches 118, 134 represent edge devices for two separate customer premises. The access switch 118 is shown connected to computer work stations 120, 122 and to an Ethernet hub 124. The Ethernet hub, in turn, is ~ 5 connected to two computer work stations 126, 128. Data communications between the access switch and the computer work stations and the Ethernet hub are carried over lOBaseT links. The access switch 134 is shown coupled to computer work stations 130, 132. Communications between the computer access switch and the computer work stations occur over l OBaseT links.
2o It is important to note that the network comprising computer work stations and the Ethernet hub shown connected to the access switch in the example in Figure 1 are for illustrative purposes only. One skilled in the art can assemble numerous other configurations without departing from the spirit of the invention. The access switch of the present invention can be coupled to any device able to communicate using lOBaseT
25 or lOBase2.
Each of the access switches comprise lOBaseS modems that communicate with each other using the lOBaseS modulation and protocol scheme disclosed herein.
The modems, including the transmitter and receiver portions, incorporated in the access switches are described in more detail hereinbelow.
A high level block diagram illustrating a sample customer premises network utilizing the lOBaseS transport facility of the present invention is shown in Figure 2.
This figure shows a central office 12 coupled to a private branch exchange (PBX) I4 and a LAN/WAN 16. The connection between the central office and the PBX carries voice s traffic and the connection between the central office and the switch 18 within the LAN/WAN carries data traffic. Both the PBX and LAN/WAN are located on the customer premises 17.
The PBX is coupled to a plurality of POTS splitters 22 which function to combine the lOBaseS transmission signal with the POTS voice signal. The LAN/WAN
to is shown comprising at least a switch 18, for example, which is coupled to the POTS
splitters via lOBaseS modems 20. The LAN/WAN can comprise any combination of networking equipment. The LAN/WAN is connected to the lOBaseS modem via a lOBaseT connection. Note that throughout this document, the term POTS splitter implies a device that functions to both split and combine the l OBaseS and POTS signals.
is POTS splitters 22 communicate to POTS splitters 24 which are typically physically located in remote locations in different areas of the customer premises. For example, the customer premises may be a large university campus with communication links spanning out to each building within the campus. The communication links would carry a combination of l OBaseS and POTS traffic. With reference to Figure 2, the links 2o between the POTS splitters 22 and 24 carry a combined lOBaseS transmission signal in addition to the POTS voice signal. The PBX and the network equipment would typically be installed in the telecommunications equipment room which also serves as the service entrance or network termination point (NTP) to the telco lines from the central office.
In the Figure, each of the POTS splitters 24 are connected to telephone voice 2s terminals 26 and lOBaseS modems 20. Any lOBaseT capable device such as computer work stations 28 can be connected to l OBaseS modems 20.
A high level block diagram illustrating an optical network unit connected to multiple customer premises via the l OBaseS transport facility of the present invention is shown in Figure 3. An example central office 150 within the PSTN 110 is shown 3o coupled to an optical network unit (ONU) 152. The fiber is terminated on a high speed switch 154 which comprises a plurality of lOBaseT ports. lOBaseS modems 156, are shown coupled via l OBaseT to the high speed switch 154. The lOBaseS modem is coupled to lOBaseS modem 162 within customer premises #1 160. The lOBaseS
modem I62, in turn, is connected to the premises distribution network 164. The premises distribution network represents any lOBaseT or lOBase2 capable network.
Shown coupled to the premises distribution network are computer work stations 166, 168.
Similarly, lOBaseS modem 158 is connected to lOBaseS modem 172 located in customer premises # 2 170. lOBaseS modem 172 is connected to the premises distribution network 174. Here too, the premises distribution network 174 represents to any lOBaseT or lOBase2 capable network. Computer work stations 176, 178 are shown connected via 1 OBaseT to the premises distribution network.
Modem Transmitter A high level block diagram illustrating the transmit portion of the lOBaseS
modem of the present invention is shown in Figure 4. The data source feeding the ~ 5 modem supplies a transmit data signal and a transmit enable signal to the transmitter interface 80 of the lOBaseS modem. The transmit interface inputs digital data to the frame first in first out (FIFO) 82. The FIFO functions to adjust the rate of data flow between data source and the modem itself. The FIFO compensates for differences in the data rates between the two devices. The output of the FIFO is input to a sync generator zo 91. header generator 89 and the randomizer 84. The sync generator functions to generate and output two sync bytes to the frame formatter 89. Preferably, the two sync bytes are F6H and 28H. The header generator functions to generate header information typically spanning a plurality of bytes. The header itself is then randomized or scrambled by randomizer 90 and subsequently encoded by encoder 92. The output of the encode is zs input to the frame formatter 89.
The data from the frame FIFO is input to the scrambler or randomizer 84 which functions to scramble the data. The output of the randomizer is input to the encoder 86 which functions to encode the data stream. The output of the encoder is input to the interleaver 88 which, in combination with Reed Solomon encoding used in the 3o transmitter and the receiver, functions to shuffle the data to help overcome impulse type noise thus resulting in improved error recovery. The output of the interleaves is input to the frame formatter 89.
The frame formatter functions to assemble a complete frame comprising the sync, header and data stream output form the interleaves. The output of the frame s formatter is input to the symbol encoder 94 which functions to generate the in band I and quadrature Q digital output signals from the input digital data stream. The I
and Q
channels are input to an in phase filter 96 and a quadrature filter 98, respectively. The output of the quadrature filter is subtracted from the output of the in band filter via a digital summer or adder 100. The output of the summer is converted to analog via D/A
to converter 102. The analog output signal is input to the line interface unit 103 which places the output signal from the transmitter onto the twisted pair wire.
Modem Receiver High level block diagrams illustrating the receive portion of the lOBaseS
modem of the present invention are shown in Figures SA and SB. The twisted pair wire is ~ s coupled to an analog front end 29 which functions to interface the 1 OBaseS modem to the wire and to amplify the received analog signal. The output of the analog front end is converted to digital via A/D converter 30. The output of the A/D converter is input to an automatic gain control (AGC) circuit 31. The output of the A/D converter is also coupled to a multiplexes (mux) 36, notch filter 32 and a narrowband interference 2o detector 34. The output of the notch filter 32 is connected to the second input of the mux 36. The narrowband interference detector functions to detect the presence of amateur radio signal which lie in the frequency range of 1.8 to 2 MHz. If su~cient signal levels in the amateur radio band are detected in the received signal, the mux is set to switch its output to be the output of the notch filter. The center frequency and the bandwidth of the 2s notch filter is set to cover the amateur radio band.
The output of the mux 36 is input to an in phase filter 38, a quadrature filter 40 and a timing control circuitry 48. The I and Q signals, output of the in phase and quadrature filters, respectively, are input to the adaptive equalizer 42. The I and Q
outputs of the adaptive equalizer are input to the slices 44. The slices generates a 3o feedback signal to control the adaptive equalizer and the timing control circuitry. The timing control circuitry outputs a signal to the voltage controlled crystal oscillator (VCXO)Iphase lock loop (PLL) 50. The output of the PLL is input to clock generating circuitry which functions to produce the clock signals used internally by the modem.
The I and Q outputs of the slicer are input to the symbol decoder 46 which s functions to make a best determination from among the constellation points according to the I and Q input signals. The bits representing the symbol are output by the symbol decoder and input to the frame deformatter 53. The frame deformatter is coupled to the deinterleaver 54, decoder 66 and the sync detector 68. The sync detector functions to match the sync pattern and hunt for multiple sync occurrences in the input data stream.
to Once a sync is detected, the header data is read from the frame by the frame deformatter and input to the decoder 66. The output of the decoder is input to the derandomizer 70.
The output of the decoder and the derandomizer are input to the header analyzer 64. The - header is analyzed to detect missing frames, perform addressing functions, etc.
The frame deformatter also outputs a data stream to the deinterleaver 54 which ~ s functions to deshuffle the data. The output of the deinterleaver is input to the decoder 56. The output of the decoder is input to the derandomizer 58 which functions to descramble the data. The output of the derandomizer is input to the frame FIFO
which adjusts for the difference in data rates between the modem and the communication device connected to it. The output of the frame FIFO is input to the receive interface 62 2o which outputs a receive data signal. A receive clock generated by the data device connected to the modem is input to the receive interface and functions to provide the clocking signal for the receive data.
Modulation Characteristics The modulation characteristics of the IOBaseS system of the present invention 2s will now be described in more detail. The l OBaseS system can transmit at full duplex on a single category-3 (CAT-3) twisted pair wire, utilizing frequency division multiplexing (FDM). The system supports two basic rates: a full rate and a half rate. The full rate transmits at 13 Mbps in each direction simultaneously. The payload rate, after accounting for forward error correction (FEC) and control overhead is 10 Mbps.
The half rate transmits at 6.5 Mbps in each direction simultaneously. The payload rate, after accounting for FEC and control overhead is 5 Mbps.
The system utilizes carrierIess amplitude and phase/quadrature amplitude modulation (CAP/QAM), with a square root raised cosine shaped filter at the transmitter s and a matched filter at the receiver. The roll-off factor of the square root raised cosine filter is 0.2. The downstream channel utilizes CAP/QAM-256, providing a spectral efficiency of 8 bits/symbol. The upstream channel utilizes CAP/QAM-16, providing a spectral efficiency of 4 bits/symbol. The following table Lists the various rates and bandwidths for the downstream and upstream channels.
Rate Channel Direction Bandwidth Full Downstream 1.95 MHz Full Upstream 3.9 MHz Half Downstream 0.975 MHz Half Upstream 1.95 MHz The upstream channel uses CAP/QAM-16 with less bits per symbol than the modulation used for the downstream channel due to the attenuation of the telephone line at higher frequencies. The upstream channel band is placed at a higher frequency than the downstream channel. Thus, the bandwidth of the upstream channel is necessarily higher t s in order to achieve the same data rate.
The transmitted power output by the system onto the twisted pair wire is preferably limited to 10 dBm ( 10 mV~ in each direction. This power limit is widely incorporated into existing standards such as ANSI and ETSI. The transmit power is limited in order to limit the power spectral density (PSD) on the wire. The downstream 2o power is thus fixed but the power transmitted on the upstream direction is controlled by the downstream link in accordance with the length of the wire so as to maintain the received power in the upstream direction at a constant level. Transmit power control is necessary in order to prevent excessive far end crosstalk to other upstream channels.
The sampling rates of the D/A in the transmitter and of the A/D in the receiver 2s are listed in the table presented below.
Rate Channel DirectionSampling Rate Full Down 6.5 MHz (4 samples/symbol) Full Up 19.5 MHz (6 samples/symbol) Half Down 3.25 MHz (4 samples/symbol) Half Up 9.75 MHz (6 samples/symbol) The performance of the system is affected by several noise sources. One of these noise sources is far-end cross talk (FEXT). The noise introduced by the FEXT
can be described by the following expression.
rM o.6 s N ~.~_.~ ~ (.f ) = 9 x 10-zo l 49 / f f Z SR (.f ) where M is the number of disturbers, i.e., the number of wire pairs in the same binder, d is the length of the wire in feet, .r is the frequency in Hz and SR(f) is the power spectral density (PSD) of the received signal. The PSD of the received signal can be expressed as the following sa (.f > = sTU) ~ ~H(f )~2 where ST(f) is the PSD of the transmitted signal and H(f} is the frequency response or the transfer function of the twisted pair at the specified wire length.
Another type of noise is near-end crosstalk (NEXT). The system, however, does not generate near end cross talk because there is no overlap in frequency between the t s upstream frequency band and the downstream frequency bands in the same binder.
Yet another source of noise that can affect system performance is thermal noise.
Typical thermal noise No in the system is at a one sided power level of -140 dBmlHz.
The system is operative to support multiple maximum wire lengths. The following table lists the various rates, wire gauges and wire lengths.
Rate Gauge Length Full 24 gauge (0.5 mm) 1,200 m (4,000 ft) Full 26 gauge (0.4 mm) 1,000 m (3,300 ft) Half 24 gauge (0.5 mm) 1,800 m (6,000 ft) Half 26 gauge (0.4 mm) 1,400 m (4,600 ft) After FEC, the bit error rate (BER) is 10-9 or less. As described below, the performance specified above is achieved with a 6 dB margin for all noise sources. The maximum ranges listed in the table above are supported by the mathematical calculations presented below.
The capacity and range of the system will now be described in more detail. The theoretical upper limit on the number of bits per second, i.e., capacity, of a transmission channel is given by the well know Shannon formula C - rn,u>lo 1 + Sn (.f ) ~r~~"~ g 2 N(.f ) where f",;~ and f",aa are the lower and upper frequencies of the channel, SR(f) is the power spectral density of the received signal and N(f) is the power spectral density of the noise.
The power spectral density of the noise is given by Io N(.~) = Nrs.~rr(.f)-~' No The power spectral density of the received signal is as given above Su (.f ) = Sr (.f ) ' I H(.r) Z
where ST(f) is the power spectral density of the transmitted signal. The transmitted signal is a raised cosine with a bandwidth excess of 20% and total power of 10 dBm.
Is H(f) is the frequency response or the transfer function of the twisted pair at the specified wire length. Since it is preferable to have a 6 dB margin in system performance, the Shannon capacity formula is utilized with an artificial factor of 0.25, i.e., 0.25~S(f) is used rather than S(f).
The full channel capacity cannot be achieved with CAP/QAM modulation, but 2o trellis coding can be used to get close to the full capacity. Without trellis coding, CAP/QAM modulation can achieve 50% or more of the capacity using sufficiently rich constellations. As a rule of thumb, CAP/QAM modulation with L constellation points can be used to transmit approximately logZL bits/symbol at a BER or 10-5, before forward error correction, if the following expression is satisfied for the signal to noise 25 ratio (SNR) SNR >_ 6 + 31og2 L dB
The SNR can be defined as 1 ~,~ Sx ~.f ~.f SNR = ~' ''"'"
.~,~~ - J min ('!m. N~.~~.f JI"n"
In the system of the present invention CAP/QAM-256 can be utilized if the SNR
of the channel is at least 30 dB. CAP/QAM-16 can be utilized if the SNR of the channel is at least 18 dB. However, a 6 dB noise margin is preferably added to these numbers to yield s a threshold of 36 dB for CAP/QAM-256 and a threshold of 24 dB for CAP/QAM-16.
The capacity and SNR for the downstream and upstream channels, at full and half rates and for wire gauges of 24 and 26 are listed in the table presented below.
Rate Channel Minimum Maximum Net Rate SNR
Direction Frequency Frequency Full Down 0.2 MHz 2.15 MHz 10 Mbps 41 dB
Full Up 2.15 MHz 6.05 MHz 10 Mbps 25 dB
Half Down 0.2 MHz I .175 MHz 10 Mbps 42 dB
Half Up 1.175 MHz 3.125 MHz 10 Mbps 30 dB
As can be seen from this table, the SNR is always greater than the required threshold for io the CAP/QAM constellation.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.
StJN~IARY OF THE INVENTION
The presents inven>~~ on p.rov iW -.s ;~ facility transport system for transporting Et:hernet over digital subscriber lines. The system, termed lOBaseS, is cad>able of transmitting of 10 Mbps Ethernet over existing cc>pper infrastructure. The system utilizes carrierlcass ampl.:ituc:le modulation/phase modulation (CAP), a version of suppressed carrier quadrature amplitude modulation :;QAN1) . The 1JL~~:~se::~ transport facility can deliver symmet.ri,cal d~:~ta at appro~: imately 13 Mbps (net 10 Mbps) over the unscr~sen~ad, t:wist.ec:~ pair telephone wires orz_ginally intended for k:~anc9widt~hs cs.f' between 3C)0 Hz and 3.4 KHz. The system utilize. frequencyy~ d:v:isiorz multiplexing (FDM) to separate downstream crZar~rat2l;~, from upstream channels.
FDM is also used to separate both the downstream and the upstream channels from i-e0'1:'S signa.l.s. The downstream and upstream dot=a ch<~nnels ar:_v .~e~~ara~ted in ~r.equenc:y =rom bands used for POTS and ISDN, er:abl_irng ser~:ic:e providers to overlay lOBaseS on existing servic:~es .
The lOBaseS system has appl.i..cations in the small office/home office (SOHO) market and can be installed in industrial areas or business d.str:i.~_-ts where most of the copper infrastructure is of shorter distances. The small office/home office market. ryas ar:eat.:l.y r~eveloped in recent years and is eagerly waiting for hAt~7 extension solutions. The need for connecting between ~;evera.l bu.-ldings of the same company or between headquarters to brancaes, dictates either usi-ng a leased 1-one such .zs TllT3 wh:i~.h :s very expensive or a POTS/ISDN modern which is ~_Tery ~s:Lcw. TL:e lOBaseS system of the present invention cars beapplied tc: tYuese mark>ets while achieving better price ~:o,~rf orz~lar",:e -or kooth the telephone company and the end user.
E;
There is t~herefcre provided in accordance with the present invention a po:i.nt t~.~ point fa=~ci 7 ity transport system for the transpc>rt of ~t.he~rnet fr<ume data over a copper infrastructure <:onnectir,.c1 <a c:entra:I o:f:fice f_<~ci_Lity to a customer premise, c:ompri~;ir_g a downstream transmission pat=h for transporting Ethernet frame data transmitted fr,>m the .-ent_ral. office faci~.ity destined to the c:u~,~..cmer pren~:i.sE~, said downstream transmission path operat:ive~ t=.o sirnult,.rneously carry both voice and Ethernet data s._gna~~s;
an upstream transmisaion path f:_,r transporting Ethernet frame data transmitted fr~:>m the <-:ust~>mer p.rernise destined to the central office facilil.:.y, sai~a up:~tream transmission path operative to sirnultaneou>:Ly car_ry L,~c~t:rn voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetria:al i_ra data transmission capacity, the Et.hernet t:ransmissi.on capacity of said downstream transmission path being s~.abst,_~ntially the same as the Ethernet ~raosmis:=~.i.on ca~~~acit.y of said upstream transmission path;
first modem means lo;~ated at. t=he ~~~entral off ice facility and coupled to one end of said down:~~i..re,~~m t:ran~~mission path and one end of said upstream tr°ansmission path;
second modem means Lc>cated at ttie c-:ustc>mer premise and coupled to the other end c:f ,raid downstream transmissicn path and the other end of said ~zp:~trearr; t: ransrnission path; and wherein said first modem mear::~ aruci said second modem means are operative to plaa:e onto and reca~ive from the copper infrastructure data frames encapsulating said Ethernet frame data.
Preferably, further, the downst: ream transmission path uti:li~zes carr:ieri_est~ airnplit;:ude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport the Et. hernet. frame data from the central office facility to the c.zstc:>me:r premi.:>c, and t:he upstream transmission path utiii:_~.f:es cvarri.erless amplitu~_te modulation phase modulation/quadratu~:e amplitude modulation (CAP/QAM) to transport the Et.hernet frame data fr;~m the customer premise to the central office fa~:, l l ity.
Preferably, in addit.i_c-gin, t:he f-:~:~.~t, modem means and t:he second modem rnean;s f~,rtr,c.r cc:~mpr_ s~e t ransm:i_tte:r means for coupling to the copper infr~:~structure, t;ne transmitter means operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto the cod>per infrastructure, and receiver means for couplng to tr~~~ cc:~sper infrast:ru,:ture, the receiver means operatiUe. t.c de-enca:osm late received data frames into Ethernet frame data anal to generate a receive data signal therE:from.
There is also provided iru ac,c:ordar~~e with the present invention a pov.~n". to pc:~:irnt f ac;i_l itvY~ t:ra.r~,~i:~ori~ syt>tem for the transport of Etherrnet fr<~mE.~ ;.iate;~ :~,~rud ~~.ain old telephone service (POTS) over a copper infrastr~.icture connecting a central office facility to a customer premise, comprising:
a downstream transmissic>n path c>r trans~>ori~,yng Ethernet frame data and POI'S tr~3nsrnit.ted from the central office facility destined to the casn::orner prerr~isc;
an upstream transmission ~:~ath for transporting Ethernet frame data and POTS transmitted from the customer premise destined to the central c:~f.t=ice far~~ili.t:y;
said downstream i::ra°csrr~iss~ic:~n I:.:~th and said upstream transmission path being syrnme~rical in data transmissions capacity, the Ethernet transmission: capacity of said downstream transmission path being sul~st:~:,ntially the same as the Ethernet transmissi.ori capac.-~.y of said upstream transmission path;
first modem means loa~ated at: thE=' central office facility and coupled to one end ot_ raid ciowr:stream transmission path and one end of said upstr.~arr tr.ar~5mi:si<.opath;
second modem means : oc:.~t:c.d at t he ustumen premise and coupled t~o the other- encl c f said down:;TrE-:am transmission path and the other end of said upstream tuansrr~ission path;
first sputter means coupled to sa i d f i rst modem means and to said copper i.nf rastr~.,act.ure, ~s~:a i d first. sol fitter means for combining and split: t ir~g Et:r~~er.ru.--.t. r~::at ~ si_gna 1_s with voi ce POTS voice signals;
second spl_it:ter means coupled to said second modem means and to said copper i.nfrast:ru-cture, s~:3:id ~:econd sp.litter means for combining and splii_ti:og Ether_net data signals with voice POTS voice signa's; and wherein said first modem means an,:x sand second modem means are operative to place orlt~.~_-~ arrcl receive from the copper infrastructure d~rta packet:.s ~~nc.;ap;ul.~:tina said Ethernet frame data.
In addition, there s prov.i.ded in accordance with the present invent:i.on a po:.nt to pc;int ra~cv_l i.t.y t ransport system fcr the transports of L~:t.fmrrrfvt fr_~rc~c zata over a copper infrastructure connecting a central. office facility to a customer premise, comprising;
a downstrearu transmission path for trans:port:ing Ethernet frame data transmitted from tree :entr.:a~~ office facility destined to the customer prern.i.se, said downstream transmission path operar_a..vE:- to s.i.mr.rltaneously carry both voice and Ethernet data sigm:~ls;
an upstream transrr:ission path for ~ransport:ing Ethernet frame data transmitted from thu uust~>.rnen premise destined to the central- offi<:e faci 1i t:.y, said l.zp.~?-re-tm tr_ansmission path 8a operative to simultaneous:l.y ~:_arry both voice and Ethernet dat=a signals;
said downs-ream t.r<<nsmi_ssion math and said upstream transmission pavr~ being s~mnuet,rm~~-: in data transmission capacity, the Etherne'~ ;=ransrniss i c>n capacity of said downstream transmission ~oat~ra bceirug substantially tree same as the Ethernet transmission capacity of said upstream transmission path;
switch means located at the central office facility and coupled to one end o.f s.=aid downstream transmis:>ion path and one end of said upstream ::ransmissic3r; path;
a network element l.e:,cated at. toe c ustomer premise and coupled to the other errd of said c~OWrzst:re:am transmission path and the other Enc. of said ~..rp5tr~eam tr~<=arnsrr.ission -oath; and wherein sai:~ swit;_:ru rnear::, arud s~~id network element are operative to place c~nt~> and receive: from true copper infrastructure data frames encapsulating said Ethernet frame data.
There is also prc>vided in accorcan~:e with the present invention a transport sy>tem f-ot_ t:rw, t.z ansport of Ethernet frame data and plain c>id telephone sfervice (POTS) voice signals over a copper :i..rnfrasl.ru~ltu.re cormectinc~ a central office facility t:o a customer- prerr:ise, comprising:
a private branch Exchange (PBX) ~~:oupled to said central office facility and operas ive to receive and transmit voice signals between said ~~t='r,tra.l. of tv: ~~~ i ac~i lity and said customer premise;
a local area network (L~~N) coozp:led t.o said central office facility and operative to receive and transmit Ethernet data signals betwe~=n said ~::entral. office facility and said customer premise;
~3 b a first plurality c:f modems coupled to said LAN and operative to convert Ethernet cia~.a~ ..ignals into analog lOBaseS signals;
a first plura:~its~ of sp:lit.ters coupled to said first plurality of mod~rms and okoerat.ive to ~~.ombine and split analog lOBaseS signals and PO'CS voice signals such that the output of each spl.itter ~.s a comkeined ~.~c:;.i_ce :vnd data. signal;
a second plurality c:~f spli..t..t:er:~ cc: upl_ec~ to said first plurality of modems and c:~perative t:.~ r_ec:eive combined voice and data signal's and split: in into analog lOB,aseS signals and POTS voice signals;
a second plural.it=y ~::~f modems <~our~ied to said second plurality of spl~_t:ters and operat:..~;e to convert analog 1C)BaseS signals to ~;thern~et chat=a sigrvals for transmission to one or more networ>,: elements;
a plurality of vo-Lce tc=1_ephc~ne de~T:aces coupled to said second plurality of spii.ttez:vs, sack ~,l.uralit:y of voice telephone device's coperativ;a ~~o comznun::.c;ata with said PBX;
wherein Fth~~rnet daaaa is transmitted in both directions between said LAN and said plurality :~f nE~twork elements at a symmetrical data rate; anti wherein Ethernet data and POTS voice signals are combined and vimul.tane-,~u~:~ly trarusmi_ti,:.ed between said first plurality of L.plitters and sa:i.~~ second plurality of splatters.
8 c:
WO 98/54856 PCT/~L98/00242 BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
Fig. 1 is a high level block diagram illustrating the lOBaseS transport facility of s the present invention as applied to a sample telephony application;
Fig. 2 is a high level block diagram illustrating a sample customer premises network utilizing the 1 OBaseS transport facility of the present invention;
Fig. 3 is a high level block illustrating an optical network unit connected to multiple customer premises via the I OBaseS transport facility;
o Fig. 4 is a high level block diagram illustrating the transmit portion of the l OBaseS modem of the present invention; and Fig. 5A and SB are high level block diagrams illustrating the receive portion of the l OBaseS modem of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Notation Used Throughout The following notation is used throughout this document.
'Perm Definition ADSL Asymmetric Digital Subscriber Line AGC Automatic Gain Control ANSI American National Standards Institute BER Bit Error Rate CAD Computer Aided Design CAP Carrierless Amplitude Modulation/Phase Modulation DBS Direct Broadcast Satellite ETSI European Telecommunications Standards Institute FDM Frequency Division Multiplexing FEC Forward Error Correction FEXT Far End Crosstalk FIFO First In First Out FTTB Fiber to the Building FTTC Fiber to the Curb FTTCab Fiber to the Cabinet FTTEx Fiber to the Exchange FTTH Fiber to the Home FTTN Fiber to the Node HFC Hybrid Fiber Coax ISDN Integrated Services Digital Network ISP Internet Service Provider LAN Local Area Network MMDS Multichannel Multipoint Distribution Service MPEG Motion Picture Entertainment Group NEXT Near End Crosstalk NIC Network Interface Card NTP Network Termination Point ONU Optical Network Unit PBX Private Branch Exchange PC Personal Computer PLL Phase Lock Loop POTS Plain Old Telephone Service PSD Power Spectral Density QAM Quadrature Amplitude Modulation QoS Quality of Service RFI Radio Frequency Interference SNMP Simple Network Management Protocol SNR Signal to Noise Ratio SOHO Small Office/Home Office TDMA Time Division Multiple Access VCXO Voltage Controlled Crystal Oscillator VDSL Very High Speed Digital Subscriber Line WAN Wide Area Network WWW World Wide Web General Description The present invention is a facility transport system for transporting Ethernet over digital subscriber lines. The system is referred to as lOBaseS and is capable of s transmitting of IO Mbps Ethernet over existing copper infrastructure. The system utilizes carrierless amplitude modulation/phase modulation (CAP) which is a version of suppressed carrier quadrature amplitude modulation (QAM). QAM is the most commonly used form of high speed modulation over voice telephone lines. The system also utilizes frequency division multiplexing (FDM) to separate downstream channels to from upstream channels. In addition, FDM is also used to separate both the downstream and the upstream channels from POTS and ISDN signals. A substantial distance in frequency is maintained between the lowest data channel and POTS frequencies to permit the use of very simple and cost effective POTS splitters, which are actually splitters/combiners. The upstream channel is placed above the downstream channel in is frequency. The downstream and upstream data channels are separated in frequency from bands used for POTS and ISDN, enabling service providers to overlay lOBaseS on existing services.
The lOBaseS system of the present invention combines copper access transmission technology of Ethernet based services with Quality of Service (QoS) 2o guaranteed by the SRVP protocol and is capable of being fully managed through an SNMP agent. The lOBaseS transport facility can deliver symmetrical data at 12.96 Mbps (net 10 Mbps) over the unscreened, twisted pair telephone wires originally intended for bandwidths of between 300 Hz and 3.4 KHz. The invention uses QAM
modulation and blind equalization to achieve a high transmission speed over existing 2s copper infrastructure. In addition, the system is able to cope with several sources of noise such as impulse noise, e.g., POTS transients, radio frequency interference (RFI) noise and crosstalk noise, i.e., both near end crosstalk (NEXT) and far end crosstalk (FEXT). In terms of RF emissions, the system can operate using underground cabling as well as overhead distribution cabling.
s Both the LAN, i.e., Ethernet frames, and POTS services, i.e., voice, may be transmitted over a common optical access network before final distribution over a copper distribution network. Alternatively, in the case where LAN services are provided by an overlay network, an Optical Network Unit (ONU) is co-located with an existing copper network distribution point where the LAN and POTS services are combined for io transmission over the existing copper distribution network.
In one installation application of the invention, lOBaseS transmission would be used on shorter exchange lines when the switch or ONU is located in a serving exchange - building.
The switch or ONU may be sited in different locations forming different is architectures for a hybrid optical network. Some of these architectures include: fiber to the cabinet (FTTCab), fiber to the curb (FTTC), fiber to the node (FTTN), fiber to the building (FTTB) and fiber to the exchange (FTTEx).
The lOBaseS transport facility of the present invention supports both LAN and POTS services sharing the same copper distribution cable. The POTS and the LAN
2o services are separated close to the point where the combined signals enter the customer premises. This is achieved by a POTS sputter filter. i.e., splitter/combiner filter, which may or may not be part of the network termination (NT). The lOBaseS system is a point to point transmission system even though the core modem is a blind modem which is able to support point to multipoint communications. The network termination interface 2s at the customer premises can be the widely used lOBaseT R.I-45 or lOBase2 BNC
interface. The customer can hook up any common l OBaseT or l OBase2 equipment, such as an Ethernet switch or hub, or any product that has an Ethernet network interface card (NIC). The network interface unit will respond to test and management messages originated by any SNMP network management system.
The system supports two latency modes that can be modified by software or through the network management: with an interieaver resulting in a latency of less than 100 msec; without an interleaver resulting in a latency of less than 1.5 msec.
lOBaseS Applications A high level block diagram illustrating the lOBaseS transport facility of the present invention as applied to a sample telephony application is shown in Figure 1. The public switched telephone network (PSTN) 110 is shown with one central office (CO) switch 114 coupled to Internet service provider (ISP) 136. The ISP comprises an access switch 138 which is shown coupled to two network elements 140, 142. Another central ~o office switch 112 is shown connected by a fiber link to the access switch 116.
The access switch 116 is shown connected to two access switches 118, 134 via 1 OBaseS connections. The two access switches 118, 134 represent edge devices for two separate customer premises. The access switch 118 is shown connected to computer work stations 120, 122 and to an Ethernet hub 124. The Ethernet hub, in turn, is ~ 5 connected to two computer work stations 126, 128. Data communications between the access switch and the computer work stations and the Ethernet hub are carried over lOBaseT links. The access switch 134 is shown coupled to computer work stations 130, 132. Communications between the computer access switch and the computer work stations occur over l OBaseT links.
2o It is important to note that the network comprising computer work stations and the Ethernet hub shown connected to the access switch in the example in Figure 1 are for illustrative purposes only. One skilled in the art can assemble numerous other configurations without departing from the spirit of the invention. The access switch of the present invention can be coupled to any device able to communicate using lOBaseT
25 or lOBase2.
Each of the access switches comprise lOBaseS modems that communicate with each other using the lOBaseS modulation and protocol scheme disclosed herein.
The modems, including the transmitter and receiver portions, incorporated in the access switches are described in more detail hereinbelow.
A high level block diagram illustrating a sample customer premises network utilizing the lOBaseS transport facility of the present invention is shown in Figure 2.
This figure shows a central office 12 coupled to a private branch exchange (PBX) I4 and a LAN/WAN 16. The connection between the central office and the PBX carries voice s traffic and the connection between the central office and the switch 18 within the LAN/WAN carries data traffic. Both the PBX and LAN/WAN are located on the customer premises 17.
The PBX is coupled to a plurality of POTS splitters 22 which function to combine the lOBaseS transmission signal with the POTS voice signal. The LAN/WAN
to is shown comprising at least a switch 18, for example, which is coupled to the POTS
splitters via lOBaseS modems 20. The LAN/WAN can comprise any combination of networking equipment. The LAN/WAN is connected to the lOBaseS modem via a lOBaseT connection. Note that throughout this document, the term POTS splitter implies a device that functions to both split and combine the l OBaseS and POTS signals.
is POTS splitters 22 communicate to POTS splitters 24 which are typically physically located in remote locations in different areas of the customer premises. For example, the customer premises may be a large university campus with communication links spanning out to each building within the campus. The communication links would carry a combination of l OBaseS and POTS traffic. With reference to Figure 2, the links 2o between the POTS splitters 22 and 24 carry a combined lOBaseS transmission signal in addition to the POTS voice signal. The PBX and the network equipment would typically be installed in the telecommunications equipment room which also serves as the service entrance or network termination point (NTP) to the telco lines from the central office.
In the Figure, each of the POTS splitters 24 are connected to telephone voice 2s terminals 26 and lOBaseS modems 20. Any lOBaseT capable device such as computer work stations 28 can be connected to l OBaseS modems 20.
A high level block diagram illustrating an optical network unit connected to multiple customer premises via the l OBaseS transport facility of the present invention is shown in Figure 3. An example central office 150 within the PSTN 110 is shown 3o coupled to an optical network unit (ONU) 152. The fiber is terminated on a high speed switch 154 which comprises a plurality of lOBaseT ports. lOBaseS modems 156, are shown coupled via l OBaseT to the high speed switch 154. The lOBaseS modem is coupled to lOBaseS modem 162 within customer premises #1 160. The lOBaseS
modem I62, in turn, is connected to the premises distribution network 164. The premises distribution network represents any lOBaseT or lOBase2 capable network.
Shown coupled to the premises distribution network are computer work stations 166, 168.
Similarly, lOBaseS modem 158 is connected to lOBaseS modem 172 located in customer premises # 2 170. lOBaseS modem 172 is connected to the premises distribution network 174. Here too, the premises distribution network 174 represents to any lOBaseT or lOBase2 capable network. Computer work stations 176, 178 are shown connected via 1 OBaseT to the premises distribution network.
Modem Transmitter A high level block diagram illustrating the transmit portion of the lOBaseS
modem of the present invention is shown in Figure 4. The data source feeding the ~ 5 modem supplies a transmit data signal and a transmit enable signal to the transmitter interface 80 of the lOBaseS modem. The transmit interface inputs digital data to the frame first in first out (FIFO) 82. The FIFO functions to adjust the rate of data flow between data source and the modem itself. The FIFO compensates for differences in the data rates between the two devices. The output of the FIFO is input to a sync generator zo 91. header generator 89 and the randomizer 84. The sync generator functions to generate and output two sync bytes to the frame formatter 89. Preferably, the two sync bytes are F6H and 28H. The header generator functions to generate header information typically spanning a plurality of bytes. The header itself is then randomized or scrambled by randomizer 90 and subsequently encoded by encoder 92. The output of the encode is zs input to the frame formatter 89.
The data from the frame FIFO is input to the scrambler or randomizer 84 which functions to scramble the data. The output of the randomizer is input to the encoder 86 which functions to encode the data stream. The output of the encoder is input to the interleaver 88 which, in combination with Reed Solomon encoding used in the 3o transmitter and the receiver, functions to shuffle the data to help overcome impulse type noise thus resulting in improved error recovery. The output of the interleaves is input to the frame formatter 89.
The frame formatter functions to assemble a complete frame comprising the sync, header and data stream output form the interleaves. The output of the frame s formatter is input to the symbol encoder 94 which functions to generate the in band I and quadrature Q digital output signals from the input digital data stream. The I
and Q
channels are input to an in phase filter 96 and a quadrature filter 98, respectively. The output of the quadrature filter is subtracted from the output of the in band filter via a digital summer or adder 100. The output of the summer is converted to analog via D/A
to converter 102. The analog output signal is input to the line interface unit 103 which places the output signal from the transmitter onto the twisted pair wire.
Modem Receiver High level block diagrams illustrating the receive portion of the lOBaseS
modem of the present invention are shown in Figures SA and SB. The twisted pair wire is ~ s coupled to an analog front end 29 which functions to interface the 1 OBaseS modem to the wire and to amplify the received analog signal. The output of the analog front end is converted to digital via A/D converter 30. The output of the A/D converter is input to an automatic gain control (AGC) circuit 31. The output of the A/D converter is also coupled to a multiplexes (mux) 36, notch filter 32 and a narrowband interference 2o detector 34. The output of the notch filter 32 is connected to the second input of the mux 36. The narrowband interference detector functions to detect the presence of amateur radio signal which lie in the frequency range of 1.8 to 2 MHz. If su~cient signal levels in the amateur radio band are detected in the received signal, the mux is set to switch its output to be the output of the notch filter. The center frequency and the bandwidth of the 2s notch filter is set to cover the amateur radio band.
The output of the mux 36 is input to an in phase filter 38, a quadrature filter 40 and a timing control circuitry 48. The I and Q signals, output of the in phase and quadrature filters, respectively, are input to the adaptive equalizer 42. The I and Q
outputs of the adaptive equalizer are input to the slices 44. The slices generates a 3o feedback signal to control the adaptive equalizer and the timing control circuitry. The timing control circuitry outputs a signal to the voltage controlled crystal oscillator (VCXO)Iphase lock loop (PLL) 50. The output of the PLL is input to clock generating circuitry which functions to produce the clock signals used internally by the modem.
The I and Q outputs of the slicer are input to the symbol decoder 46 which s functions to make a best determination from among the constellation points according to the I and Q input signals. The bits representing the symbol are output by the symbol decoder and input to the frame deformatter 53. The frame deformatter is coupled to the deinterleaver 54, decoder 66 and the sync detector 68. The sync detector functions to match the sync pattern and hunt for multiple sync occurrences in the input data stream.
to Once a sync is detected, the header data is read from the frame by the frame deformatter and input to the decoder 66. The output of the decoder is input to the derandomizer 70.
The output of the decoder and the derandomizer are input to the header analyzer 64. The - header is analyzed to detect missing frames, perform addressing functions, etc.
The frame deformatter also outputs a data stream to the deinterleaver 54 which ~ s functions to deshuffle the data. The output of the deinterleaver is input to the decoder 56. The output of the decoder is input to the derandomizer 58 which functions to descramble the data. The output of the derandomizer is input to the frame FIFO
which adjusts for the difference in data rates between the modem and the communication device connected to it. The output of the frame FIFO is input to the receive interface 62 2o which outputs a receive data signal. A receive clock generated by the data device connected to the modem is input to the receive interface and functions to provide the clocking signal for the receive data.
Modulation Characteristics The modulation characteristics of the IOBaseS system of the present invention 2s will now be described in more detail. The l OBaseS system can transmit at full duplex on a single category-3 (CAT-3) twisted pair wire, utilizing frequency division multiplexing (FDM). The system supports two basic rates: a full rate and a half rate. The full rate transmits at 13 Mbps in each direction simultaneously. The payload rate, after accounting for forward error correction (FEC) and control overhead is 10 Mbps.
The half rate transmits at 6.5 Mbps in each direction simultaneously. The payload rate, after accounting for FEC and control overhead is 5 Mbps.
The system utilizes carrierIess amplitude and phase/quadrature amplitude modulation (CAP/QAM), with a square root raised cosine shaped filter at the transmitter s and a matched filter at the receiver. The roll-off factor of the square root raised cosine filter is 0.2. The downstream channel utilizes CAP/QAM-256, providing a spectral efficiency of 8 bits/symbol. The upstream channel utilizes CAP/QAM-16, providing a spectral efficiency of 4 bits/symbol. The following table Lists the various rates and bandwidths for the downstream and upstream channels.
Rate Channel Direction Bandwidth Full Downstream 1.95 MHz Full Upstream 3.9 MHz Half Downstream 0.975 MHz Half Upstream 1.95 MHz The upstream channel uses CAP/QAM-16 with less bits per symbol than the modulation used for the downstream channel due to the attenuation of the telephone line at higher frequencies. The upstream channel band is placed at a higher frequency than the downstream channel. Thus, the bandwidth of the upstream channel is necessarily higher t s in order to achieve the same data rate.
The transmitted power output by the system onto the twisted pair wire is preferably limited to 10 dBm ( 10 mV~ in each direction. This power limit is widely incorporated into existing standards such as ANSI and ETSI. The transmit power is limited in order to limit the power spectral density (PSD) on the wire. The downstream 2o power is thus fixed but the power transmitted on the upstream direction is controlled by the downstream link in accordance with the length of the wire so as to maintain the received power in the upstream direction at a constant level. Transmit power control is necessary in order to prevent excessive far end crosstalk to other upstream channels.
The sampling rates of the D/A in the transmitter and of the A/D in the receiver 2s are listed in the table presented below.
Rate Channel DirectionSampling Rate Full Down 6.5 MHz (4 samples/symbol) Full Up 19.5 MHz (6 samples/symbol) Half Down 3.25 MHz (4 samples/symbol) Half Up 9.75 MHz (6 samples/symbol) The performance of the system is affected by several noise sources. One of these noise sources is far-end cross talk (FEXT). The noise introduced by the FEXT
can be described by the following expression.
rM o.6 s N ~.~_.~ ~ (.f ) = 9 x 10-zo l 49 / f f Z SR (.f ) where M is the number of disturbers, i.e., the number of wire pairs in the same binder, d is the length of the wire in feet, .r is the frequency in Hz and SR(f) is the power spectral density (PSD) of the received signal. The PSD of the received signal can be expressed as the following sa (.f > = sTU) ~ ~H(f )~2 where ST(f) is the PSD of the transmitted signal and H(f} is the frequency response or the transfer function of the twisted pair at the specified wire length.
Another type of noise is near-end crosstalk (NEXT). The system, however, does not generate near end cross talk because there is no overlap in frequency between the t s upstream frequency band and the downstream frequency bands in the same binder.
Yet another source of noise that can affect system performance is thermal noise.
Typical thermal noise No in the system is at a one sided power level of -140 dBmlHz.
The system is operative to support multiple maximum wire lengths. The following table lists the various rates, wire gauges and wire lengths.
Rate Gauge Length Full 24 gauge (0.5 mm) 1,200 m (4,000 ft) Full 26 gauge (0.4 mm) 1,000 m (3,300 ft) Half 24 gauge (0.5 mm) 1,800 m (6,000 ft) Half 26 gauge (0.4 mm) 1,400 m (4,600 ft) After FEC, the bit error rate (BER) is 10-9 or less. As described below, the performance specified above is achieved with a 6 dB margin for all noise sources. The maximum ranges listed in the table above are supported by the mathematical calculations presented below.
The capacity and range of the system will now be described in more detail. The theoretical upper limit on the number of bits per second, i.e., capacity, of a transmission channel is given by the well know Shannon formula C - rn,u>lo 1 + Sn (.f ) ~r~~"~ g 2 N(.f ) where f",;~ and f",aa are the lower and upper frequencies of the channel, SR(f) is the power spectral density of the received signal and N(f) is the power spectral density of the noise.
The power spectral density of the noise is given by Io N(.~) = Nrs.~rr(.f)-~' No The power spectral density of the received signal is as given above Su (.f ) = Sr (.f ) ' I H(.r) Z
where ST(f) is the power spectral density of the transmitted signal. The transmitted signal is a raised cosine with a bandwidth excess of 20% and total power of 10 dBm.
Is H(f) is the frequency response or the transfer function of the twisted pair at the specified wire length. Since it is preferable to have a 6 dB margin in system performance, the Shannon capacity formula is utilized with an artificial factor of 0.25, i.e., 0.25~S(f) is used rather than S(f).
The full channel capacity cannot be achieved with CAP/QAM modulation, but 2o trellis coding can be used to get close to the full capacity. Without trellis coding, CAP/QAM modulation can achieve 50% or more of the capacity using sufficiently rich constellations. As a rule of thumb, CAP/QAM modulation with L constellation points can be used to transmit approximately logZL bits/symbol at a BER or 10-5, before forward error correction, if the following expression is satisfied for the signal to noise 25 ratio (SNR) SNR >_ 6 + 31og2 L dB
The SNR can be defined as 1 ~,~ Sx ~.f ~.f SNR = ~' ''"'"
.~,~~ - J min ('!m. N~.~~.f JI"n"
In the system of the present invention CAP/QAM-256 can be utilized if the SNR
of the channel is at least 30 dB. CAP/QAM-16 can be utilized if the SNR of the channel is at least 18 dB. However, a 6 dB noise margin is preferably added to these numbers to yield s a threshold of 36 dB for CAP/QAM-256 and a threshold of 24 dB for CAP/QAM-16.
The capacity and SNR for the downstream and upstream channels, at full and half rates and for wire gauges of 24 and 26 are listed in the table presented below.
Rate Channel Minimum Maximum Net Rate SNR
Direction Frequency Frequency Full Down 0.2 MHz 2.15 MHz 10 Mbps 41 dB
Full Up 2.15 MHz 6.05 MHz 10 Mbps 25 dB
Half Down 0.2 MHz I .175 MHz 10 Mbps 42 dB
Half Up 1.175 MHz 3.125 MHz 10 Mbps 30 dB
As can be seen from this table, the SNR is always greater than the required threshold for io the CAP/QAM constellation.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.
Claims (15)
1. A point to point facility transport system for the transport of Ethernet name data over a copper infrastructure connecting a central office facility to a customer premise, comprising:
a downstream transmission path for transporting Ethernet frame data transmitted from the central office facility destined to the customer premise, said downstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
an upstream transmission path for transporting Ethernet frame data transmitted from the customer premise destined to the central office facility, said upstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetrical in data transmission capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
first modem means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
second modem means located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path; and wherein said first modem means, and said second modem means are operative to place onto and receive from the copper infrastructure data frames encapsulating said Ethernet frame data.
a downstream transmission path for transporting Ethernet frame data transmitted from the central office facility destined to the customer premise, said downstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
an upstream transmission path for transporting Ethernet frame data transmitted from the customer premise destined to the central office facility, said upstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetrical in data transmission capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
first modem means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
second modem means located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path; and wherein said first modem means, and said second modem means are operative to place onto and receive from the copper infrastructure data frames encapsulating said Ethernet frame data.
2. The facility transport system according to claim 1, wherein said downstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said central office facility to customer premise.
3. The facility transport system according to claim 1, wherein said upstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said customer premise to said central office facility.
4. The facility transport system according to claim 1, wherein said first modern, means sand said second modem means further comprise:
transmitter means for coupling to said coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive data signal therefrom.
transmitter means for coupling to said coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive data signal therefrom.
5. A point to point facility transport system for the transport of Ethernet frame data and plain old telephone service (POTS) over a copper infrastructure connecting a central office facility to a customer premise, comprising:
a downstream transmission path for transporting Ethernet frame data and POTS transmitted from the central office facility destined to the customer premise;
an upstream transmission path for transporting Ethernet frame data and POTS transmitted from the customer premise destined to the central office facility;
said downstream transmission path and said upstream transmission path being symmetrical in data transmissions capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
first modem means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
second modem means located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path;
first splitter means coupled to said first modem means and to said copper infrastructure, said first splitter means for combining and splitting Ethernet data signals with voice POTS voice signals;
second splitter means coupled to said second modem means and to said copper infrastructure, said second splitter means for combining and splitting Ethernet data signals with voice POTS voice signals; and wherein said first modem means and said second modem means are operative to place onto and receive from the copper infrastructure data packets encapsulating said Ethernet frame data.
a downstream transmission path for transporting Ethernet frame data and POTS transmitted from the central office facility destined to the customer premise;
an upstream transmission path for transporting Ethernet frame data and POTS transmitted from the customer premise destined to the central office facility;
said downstream transmission path and said upstream transmission path being symmetrical in data transmissions capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
first modem means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
second modem means located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path;
first splitter means coupled to said first modem means and to said copper infrastructure, said first splitter means for combining and splitting Ethernet data signals with voice POTS voice signals;
second splitter means coupled to said second modem means and to said copper infrastructure, said second splitter means for combining and splitting Ethernet data signals with voice POTS voice signals; and wherein said first modem means and said second modem means are operative to place onto and receive from the copper infrastructure data packets encapsulating said Ethernet frame data.
6. The facility transport system according to claim 5, wherein said downstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said central office facility to said customer premise.
7. The facility transport system according to claim 5, wherein said upstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said customer premise to said central office facility.
8. The facility transport system according to claim 5, wherein said first modern means and said second modem means further comprise:
transmitter for coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive date signal therefrom.
transmitter for coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive date signal therefrom.
9. A point to point facility transport system for the transport of Ethernet frame data over a copper infrastructure connecting a central of facility to a customer premise, comprising:
a downstream transmission path for transporting Ethernet frame data transmitted from the central office facility destined to the customer premise, said downstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
an upstream transmission path for transporting Ethernet frame data transmitted from the customer premise destined to the central office facility, said upstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetrical in data transmission capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
switch means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
a network element located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path; and wherein said switch means and said network element are operative to place onto and receive from the copper infrastructure data frames encapsulating said Ethernet frame data.
a downstream transmission path for transporting Ethernet frame data transmitted from the central office facility destined to the customer premise, said downstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
an upstream transmission path for transporting Ethernet frame data transmitted from the customer premise destined to the central office facility, said upstream transmission path operative to simultaneously carry both voice and Ethernet data signals;
said downstream transmission path and said upstream transmission path being symmetrical in data transmission capacity, the Ethernet transmission capacity of said downstream transmission path being substantially the same as the Ethernet transmission capacity of said upstream transmission path;
switch means located at the central office facility and coupled to one end of said downstream transmission path and one end of said upstream transmission path;
a network element located at the customer premise and coupled to the other end of said downstream transmission path and the other end of said upstream transmission path; and wherein said switch means and said network element are operative to place onto and receive from the copper infrastructure data frames encapsulating said Ethernet frame data.
10. The facility transport system according to claim 9, wherein said downstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said central office facility to said customer premise.
11. The facility transport system according to claim 9, wherein said upstream transmission path utilizes carrierless amplitude modulation phase modulation/quadrature amplitude modulation (CAP/QAM) to transport said Ethernet frame data from said customer premise to said central office facility.
12. The facility transport system according to claim 9, wherein said switch means and said network element further comprise:
transmitter means for coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive data signal therefrom.
transmitter means for coupling to said copper infrastructure, said transmitter means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to encapsulate received Ethernet frame data into data frames and to generate a transmit signal therefrom suitable for transmission onto said copper infrastructure; and receiver means for coupling to said copper infrastructure, said receiver means is operative to de-encapsulate received data frames into Ethernet frame data and to generate a receive data signal therefrom.
13. The facility transport system according to claim 9, wherein said network element comprises a modem.
14. The facility transport system according to claim 9, wherein said network element comprises a customer premise local area network (LAN) switch.
15. A transport system for the transport of Ehternet frame data and plain old telephone service (POTS) voice signals over a copper infrastructure connecting a central office facility to a customer premise, comprising:
a private branch exchange (PBX) coupled to said central office facility and operative to receive and transmit voice signals between said central office facility and said customer premise;
a local area network (LAN) coupled to said central office facility and operative to receive and transmit Ethernet data signals between said central office facility and said customer premise;
a first plurality of modems coupled to said LAN and operative to convert Ethernet data signals into analog 10BaseS signals;
a first plurality of splitters coupled to said first plurality of modems and operative to combine and split analog 10BaseS signals and POTS voice signals such that the output of each splitter is a combined voice and data signal;
a second plurality of splitters coupled to said first plurality of modems and operative to receive combined voice and data signals and split in into analog 10BaseS signals and POTS voice signals;
a second plurality of modems coupled to said second plurality of splitters and operative to convert analog 10BaseS signals to Ethernet data signals for transmission to one or more network elements;
a plurality of voice telephone devices coupled to said second plurality of splitters, said plurality of voice telephone devices operative to communicate with said PBX;
wherein Ethernet data is transmitted in both directions between said LAN and said plurality of network elements at a symmetrical data rate; and wherein Ethernet data and POTS voice signals are combined and simultaneously transmitted between said first plurality of splitters and said second plurality of splitters.
28~
a private branch exchange (PBX) coupled to said central office facility and operative to receive and transmit voice signals between said central office facility and said customer premise;
a local area network (LAN) coupled to said central office facility and operative to receive and transmit Ethernet data signals between said central office facility and said customer premise;
a first plurality of modems coupled to said LAN and operative to convert Ethernet data signals into analog 10BaseS signals;
a first plurality of splitters coupled to said first plurality of modems and operative to combine and split analog 10BaseS signals and POTS voice signals such that the output of each splitter is a combined voice and data signal;
a second plurality of splitters coupled to said first plurality of modems and operative to receive combined voice and data signals and split in into analog 10BaseS signals and POTS voice signals;
a second plurality of modems coupled to said second plurality of splitters and operative to convert analog 10BaseS signals to Ethernet data signals for transmission to one or more network elements;
a plurality of voice telephone devices coupled to said second plurality of splitters, said plurality of voice telephone devices operative to communicate with said PBX;
wherein Ethernet data is transmitted in both directions between said LAN and said plurality of network elements at a symmetrical data rate; and wherein Ethernet data and POTS voice signals are combined and simultaneously transmitted between said first plurality of splitters and said second plurality of splitters.
28~
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/866,831 US6088368A (en) | 1997-05-30 | 1997-05-30 | Ethernet transport facility over digital subscriber lines |
| US08/866,831 | 1997-05-30 | ||
| PCT/IL1998/000242 WO1998054856A1 (en) | 1997-05-30 | 1998-05-26 | Ethernet transport facility over digital subscriber lines |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2294970A1 CA2294970A1 (en) | 1998-12-03 |
| CA2294970C true CA2294970C (en) | 2003-07-15 |
Family
ID=25348516
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002294970A Expired - Lifetime CA2294970C (en) | 1997-05-30 | 1998-05-26 | Ethernet transport facility over digital subscriber lines |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US6088368A (en) |
| EP (1) | EP1000475A4 (en) |
| AU (1) | AU751942B2 (en) |
| CA (1) | CA2294970C (en) |
| IL (1) | IL133183A0 (en) |
| WO (1) | WO1998054856A1 (en) |
Families Citing this family (94)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7168084B1 (en) | 1992-12-09 | 2007-01-23 | Sedna Patent Services, Llc | Method and apparatus for targeting virtual objects |
| US9286294B2 (en) | 1992-12-09 | 2016-03-15 | Comcast Ip Holdings I, Llc | Video and digital multimedia aggregator content suggestion engine |
| US6038616A (en) * | 1997-12-15 | 2000-03-14 | Int Labs, Inc. | Computer system with remotely located interface where signals are encoded at the computer system, transferred through a 4-wire cable, and decoded at the interface |
| US6347075B1 (en) * | 1997-12-31 | 2002-02-12 | At&T Corp. | Circuit to provide backup telephone service for a multiple service access system using a twisted pair |
| US20030016794A1 (en) * | 1998-05-14 | 2003-01-23 | John D.W. Brothers | Communication of information via two wire lines |
| US6195385B1 (en) * | 1998-06-30 | 2001-02-27 | Cisco Systems, Inc. | HTU-C clocking from a single source |
| US6480510B1 (en) | 1998-07-28 | 2002-11-12 | Serconet Ltd. | Local area network of serial intelligent cells |
| US6567981B1 (en) | 1998-08-03 | 2003-05-20 | Elysium Broadband Inc. | Audio/video signal redistribution system |
| US6643321B1 (en) * | 1998-09-30 | 2003-11-04 | Alvarion Ltd. | Method for rapid synchronization of a point to multipoint communication system |
| US6434123B1 (en) | 1998-12-28 | 2002-08-13 | Ericsson Inc. | Apparatus and method for broadband data communication |
| US6621831B1 (en) * | 1999-01-05 | 2003-09-16 | Legerity, Inc. | Method and apparatus for verifying and correcting connectivity |
| US7027537B1 (en) | 1999-03-05 | 2006-04-11 | The Board Of Trustees Of The Leland Stanford Junior University | Iterative multi-user detection |
| WO2000052845A1 (en) * | 1999-03-05 | 2000-09-08 | The Board Of Trustrees, Leland Stanford Junior University | Iterative multi-user detection |
| US6584079B1 (en) * | 1999-04-15 | 2003-06-24 | Advanced Micro Devices, Inc. | Apparatus and method of implementing a home network by filtering ISDN-based signals within the customer premises |
| US6483902B1 (en) * | 1999-04-30 | 2002-11-19 | Wayport, Inc. | System and method for retrofitting existing building telecommunications infrastructures |
| US6680940B1 (en) * | 1999-05-19 | 2004-01-20 | 3Com Corporation | System for transporting ethernet frames over very high speed digital subscriber lines |
| US6608834B1 (en) * | 1999-05-26 | 2003-08-19 | 3 Com Corporation | System for encapsulating Ethernet frames over very high speed digital subscriber lines |
| US6587476B1 (en) * | 1999-05-26 | 2003-07-01 | 3 Com Corporation | Ethernet frame encapsulation over VDSL using HDLC |
| US7697507B2 (en) * | 1999-05-27 | 2010-04-13 | Infineon Technologies Ag | Ethernet transport over a telephone line |
| US6445712B1 (en) * | 1999-06-08 | 2002-09-03 | Verizon Laboratories Inc. | Broadband architecture using existing twisted pair |
| US6532279B1 (en) | 1999-06-11 | 2003-03-11 | David D. Goodman | High-speed data communication over a residential telephone wiring network |
| US7088921B1 (en) * | 1999-06-11 | 2006-08-08 | Lucent Technologies Inc. | System for operating an Ethernet data network over a passive optical network access system |
| US6160810A (en) | 1999-06-24 | 2000-12-12 | Qwest Communications International Inc. | ATM based VDSL communication system having meta signaling for switching a subscriber between different data service providers |
| US6690677B1 (en) | 1999-07-20 | 2004-02-10 | Serconet Ltd. | Network for telephony and data communication |
| US6662677B2 (en) * | 1999-10-15 | 2003-12-16 | Teleflex Incorporated | Adjustable pedal assembly (banana rod) |
| US6549616B1 (en) | 2000-03-20 | 2003-04-15 | Serconet Ltd. | Telephone outlet for implementing a local area network over telephone lines and a local area network using such outlets |
| US6760847B1 (en) * | 2000-04-13 | 2004-07-06 | Nortel Networks Limited | Method for performing subscriber loop disturber recognition by comparing measured sample power spectral densities with a set of known power spectral densities |
| IL135744A (en) | 2000-04-18 | 2008-08-07 | Mosaid Technologies Inc | Telephone communication system over a single telephone line |
| US6842459B1 (en) | 2000-04-19 | 2005-01-11 | Serconet Ltd. | Network combining wired and non-wired segments |
| US6377665B1 (en) * | 2000-05-09 | 2002-04-23 | Advanced Micro Devices, Inc. | Apparatus and method of implementing a universal home network on a customer premises UPN telephone lines |
| US6393109B1 (en) * | 2000-05-09 | 2002-05-21 | Advanced Micro Devices, Inc. | Apparatus and method of coupling home network signals between an analog phone line and a digital UPN line |
| US7016822B2 (en) * | 2000-06-30 | 2006-03-21 | Qwest Communications International, Inc. | Method and system for modeling near end crosstalk in a binder group |
| US7111163B1 (en) | 2000-07-10 | 2006-09-19 | Alterwan, Inc. | Wide area network using internet with quality of service |
| US6778549B1 (en) * | 2000-09-22 | 2004-08-17 | Advanced Micro Devices, Inc. | Coupling device connecting multiple pots lines in an HPNA environment |
| DE10102144C2 (en) * | 2001-01-18 | 2003-02-13 | Infineon Technologies Ag | Broadband optical transmission device |
| US7339605B2 (en) * | 2004-04-16 | 2008-03-04 | Polycom, Inc. | Conference link between a speakerphone and a video conference unit |
| US8964604B2 (en) * | 2000-12-26 | 2015-02-24 | Polycom, Inc. | Conference endpoint instructing conference bridge to dial phone number |
| US9001702B2 (en) * | 2000-12-26 | 2015-04-07 | Polycom, Inc. | Speakerphone using a secure audio connection to initiate a second secure connection |
| US8977683B2 (en) | 2000-12-26 | 2015-03-10 | Polycom, Inc. | Speakerphone transmitting password information to a remote device |
| US7864938B2 (en) * | 2000-12-26 | 2011-01-04 | Polycom, Inc. | Speakerphone transmitting URL information to a remote device |
| US7221663B2 (en) * | 2001-12-31 | 2007-05-22 | Polycom, Inc. | Method and apparatus for wideband conferencing |
| US8948059B2 (en) | 2000-12-26 | 2015-02-03 | Polycom, Inc. | Conference endpoint controlling audio volume of a remote device |
| DE10100363A1 (en) * | 2001-01-05 | 2002-08-01 | Infineon Technologies Ag | Ethernet calibrating equipment |
| US8976712B2 (en) * | 2001-05-10 | 2015-03-10 | Polycom, Inc. | Speakerphone and conference bridge which request and perform polling operations |
| US8934382B2 (en) * | 2001-05-10 | 2015-01-13 | Polycom, Inc. | Conference endpoint controlling functions of a remote device |
| EP1388080A4 (en) * | 2001-05-10 | 2006-10-25 | Polycom Israel Ltd | Control unit for multipoint multimedia/audio system |
| US7099412B2 (en) * | 2001-05-14 | 2006-08-29 | Texas Instruments Incorporated | Sequential decoding with backtracking and adaptive equalization to combat narrowband interference |
| US20020186699A1 (en) * | 2001-06-08 | 2002-12-12 | Kwok Timothy Chung Hing | System and method for providing high-speed communications access over an electrical network |
| US6956825B2 (en) * | 2001-06-26 | 2005-10-18 | D-Link Corp. | System for managing community ethernet switch and apparatus thereof |
| IL144158A (en) | 2001-07-05 | 2011-06-30 | Mosaid Technologies Inc | Outlet for connecting an analog telephone set to a digital data network carrying voice signals in digital form |
| US7793326B2 (en) | 2001-08-03 | 2010-09-07 | Comcast Ip Holdings I, Llc | Video and digital multimedia aggregator |
| US7908628B2 (en) | 2001-08-03 | 2011-03-15 | Comcast Ip Holdings I, Llc | Video and digital multimedia aggregator content coding and formatting |
| US20030190887A1 (en) * | 2001-09-14 | 2003-10-09 | Arne Hook | System and method for wireless multimedia communication |
| US7415062B1 (en) * | 2001-09-25 | 2008-08-19 | Cisco Technology, Inc. | Switching system supporting data communications supported by multiple power spectra |
| US7436842B2 (en) | 2001-10-11 | 2008-10-14 | Serconet Ltd. | Outlet with analog signal adapter, a method for use thereof and a network using said outlet |
| US7684798B2 (en) * | 2001-11-09 | 2010-03-23 | Nokia Corporation | Method of pre-authorizing handovers among access routers in communication networks |
| DE10158808B4 (en) * | 2001-11-30 | 2006-06-08 | Infineon Technologies Ag | Telecommunication system for bidirectional transmission of data and voice signals |
| US6724727B2 (en) | 2001-12-03 | 2004-04-20 | Nokia Corporation | Policy-based forward error correction in packet networks |
| US20030115259A1 (en) * | 2001-12-18 | 2003-06-19 | Nokia Corporation | System and method using legacy servers in reliable server pools |
| US7177902B2 (en) * | 2001-12-28 | 2007-02-13 | Nokia, Inc. | Remotely controlling a computer via simulated keyboard events |
| US8705719B2 (en) | 2001-12-31 | 2014-04-22 | Polycom, Inc. | Speakerphone and conference bridge which receive and provide participant monitoring information |
| US8947487B2 (en) * | 2001-12-31 | 2015-02-03 | Polycom, Inc. | Method and apparatus for combining speakerphone and video conference unit operations |
| US8885523B2 (en) * | 2001-12-31 | 2014-11-11 | Polycom, Inc. | Speakerphone transmitting control information embedded in audio information through a conference bridge |
| US7978838B2 (en) * | 2001-12-31 | 2011-07-12 | Polycom, Inc. | Conference endpoint instructing conference bridge to mute participants |
| US8102984B2 (en) | 2001-12-31 | 2012-01-24 | Polycom Inc. | Speakerphone and conference bridge which receive and provide participant monitoring information |
| US8934381B2 (en) | 2001-12-31 | 2015-01-13 | Polycom, Inc. | Conference endpoint instructing a remote device to establish a new connection |
| US7742588B2 (en) | 2001-12-31 | 2010-06-22 | Polycom, Inc. | Speakerphone establishing and using a second connection of graphics information |
| US8023458B2 (en) * | 2001-12-31 | 2011-09-20 | Polycom, Inc. | Method and apparatus for wideband conferencing |
| US8223942B2 (en) | 2001-12-31 | 2012-07-17 | Polycom, Inc. | Conference endpoint requesting and receiving billing information from a conference bridge |
| US7787605B2 (en) * | 2001-12-31 | 2010-08-31 | Polycom, Inc. | Conference bridge which decodes and responds to control information embedded in audio information |
| US8144854B2 (en) | 2001-12-31 | 2012-03-27 | Polycom Inc. | Conference bridge which detects control information embedded in audio information to prioritize operations |
| TW564613B (en) * | 2002-05-10 | 2003-12-01 | Accton Technology Corp | Very high bit rate digital subscriber line modem |
| US7013318B2 (en) * | 2002-05-29 | 2006-03-14 | Raytheon Company | Method and system for encapsulating cells |
| IL154234A (en) | 2003-01-30 | 2010-12-30 | Mosaid Technologies Inc | Method and system for providing dc power on local telephone lines |
| IL154921A (en) | 2003-03-13 | 2011-02-28 | Mosaid Technologies Inc | Telephone system having multiple distinct sources and accessories therefor |
| IL157787A (en) | 2003-09-07 | 2010-12-30 | Mosaid Technologies Inc | Modular outlet for data communications network |
| IL159838A0 (en) | 2004-01-13 | 2004-06-20 | Yehuda Binder | Information device |
| IL161869A (en) | 2004-05-06 | 2014-05-28 | Serconet Ltd | System and method for carrying a wireless based signal over wiring |
| US7940746B2 (en) | 2004-08-24 | 2011-05-10 | Comcast Cable Holdings, Llc | Method and system for locating a voice over internet protocol (VoIP) device connected to a network |
| US7873058B2 (en) | 2004-11-08 | 2011-01-18 | Mosaid Technologies Incorporated | Outlet with analog signal adapter, a method for use thereof and a network using said outlet |
| KR100652790B1 (en) * | 2005-02-17 | 2006-12-01 | 주식회사 커밍미디어 | High-speed transmission system of quality of service on hybrid-fiber coaxial for internet protocol broadcasting service |
| US7796565B2 (en) | 2005-06-08 | 2010-09-14 | Polycom, Inc. | Mixed voice and spread spectrum data signaling with multiplexing multiple users with CDMA |
| US8126029B2 (en) * | 2005-06-08 | 2012-02-28 | Polycom, Inc. | Voice interference correction for mixed voice and spread spectrum data signaling |
| US8199791B2 (en) | 2005-06-08 | 2012-06-12 | Polycom, Inc. | Mixed voice and spread spectrum data signaling with enhanced concealment of data |
| US20070081825A1 (en) * | 2005-10-06 | 2007-04-12 | Damiano Rossetti | Multimode distance extension |
| US7813451B2 (en) | 2006-01-11 | 2010-10-12 | Mobileaccess Networks Ltd. | Apparatus and method for frequency shifting of a wireless signal and systems using frequency shifting |
| US20070253443A1 (en) * | 2006-04-27 | 2007-11-01 | Sbc Knowledge Ventures L.P. | Data services over G.SHDSL transport infrastructure |
| US20080279311A1 (en) * | 2007-05-07 | 2008-11-13 | Roger Lee Jungerman | AD Converter Bandwidth Enhancement Using An IQ Demodulator And Low Frequency Cross-Over Network |
| EP2203799A4 (en) | 2007-10-22 | 2017-05-17 | Mobileaccess Networks Ltd. | Communication system using low bandwidth wires |
| US8175649B2 (en) | 2008-06-20 | 2012-05-08 | Corning Mobileaccess Ltd | Method and system for real time control of an active antenna over a distributed antenna system |
| US8897215B2 (en) | 2009-02-08 | 2014-11-25 | Corning Optical Communications Wireless Ltd | Communication system using cables carrying ethernet signals |
| EP2829152A2 (en) | 2012-03-23 | 2015-01-28 | Corning Optical Communications Wireless Ltd. | Radio-frequency integrated circuit (rfic) chip(s) for providing distributed antenna system functionalities, and related components, systems, and methods |
| US9184960B1 (en) | 2014-09-25 | 2015-11-10 | Corning Optical Communications Wireless Ltd | Frequency shifting a communications signal(s) in a multi-frequency distributed antenna system (DAS) to avoid or reduce frequency interference |
| US10057111B2 (en) | 2015-12-04 | 2018-08-21 | General Electric Company | Vehicle consist configuration control |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5247347A (en) * | 1991-09-27 | 1993-09-21 | Bell Atlantic Network Services, Inc. | Pstn architecture for video-on-demand services |
| JP2726630B2 (en) * | 1994-12-07 | 1998-03-11 | インターナショナル・ビジネス・マシーンズ・コーポレイション | Gateway device and gateway method |
| US5784683A (en) * | 1995-05-16 | 1998-07-21 | Bell Atlantic Network Services, Inc. | Shared use video processing systems for distributing program signals from multiplexed digitized information signals |
| US5812786A (en) * | 1995-06-21 | 1998-09-22 | Bell Atlantic Network Services, Inc. | Variable rate and variable mode transmission system |
| US5790548A (en) * | 1996-04-18 | 1998-08-04 | Bell Atlantic Network Services, Inc. | Universal access multimedia data network |
-
1997
- 1997-05-30 US US08/866,831 patent/US6088368A/en not_active Expired - Lifetime
-
1998
- 1998-05-26 WO PCT/IL1998/000242 patent/WO1998054856A1/en active IP Right Grant
- 1998-05-26 EP EP98921718A patent/EP1000475A4/en not_active Withdrawn
- 1998-05-26 AU AU74486/98A patent/AU751942B2/en not_active Expired
- 1998-05-26 IL IL13318398A patent/IL133183A0/en unknown
- 1998-05-26 CA CA002294970A patent/CA2294970C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2294970A1 (en) | 1998-12-03 |
| WO1998054856A1 (en) | 1998-12-03 |
| IL133183A0 (en) | 2001-03-19 |
| US6088368A (en) | 2000-07-11 |
| AU751942B2 (en) | 2002-09-05 |
| EP1000475A4 (en) | 2006-03-22 |
| AU7448698A (en) | 1998-12-30 |
| EP1000475A1 (en) | 2000-05-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2294970C (en) | Ethernet transport facility over digital subscriber lines | |
| US9088435B2 (en) | Ethernet transport over a telephone line | |
| US7054376B1 (en) | High data rate ethernet transport facility over digital subscriber lines | |
| US6587476B1 (en) | Ethernet frame encapsulation over VDSL using HDLC | |
| US7136397B2 (en) | Network architecture and system for delivering bi-directional xDSL based services | |
| US6480487B1 (en) | Digital loop carrier remote terminal having integrated digital subscriber plug-in line cards for multiplexing of telephone and broadband signals | |
| US6731678B1 (en) | System and method for extending the operating range and/or increasing the bandwidth of a communication link | |
| US7146104B2 (en) | Method and system for providing a return data path for legacy terminals by using existing electrical waveguides of a structure | |
| KR20010023363A (en) | Apparatus and method for concurrent voice and data transmission | |
| WO2003021803A1 (en) | Active cable modem outside customer premises | |
| KR20030091949A (en) | Delivering video over an atm/dsl network using a multi-layered video coding system | |
| EP1173018B1 (en) | Architecture and method for providing interactive broadband products and services using existing telephone plant | |
| US7903634B2 (en) | System for encapsulating Ethernet frames over very high speed digital subscriber lines | |
| US7023910B1 (en) | Dual-line DSL system and method | |
| Milanovic et al. | ATM over ADSL probe in Telecom Italia environment | |
| Lawrence et al. | Broadband access to the home on copper | |
| Peden et al. | From voice‐band modems to DSL technologies | |
| US8391179B2 (en) | Method and device for data communication and communication system comprising such device | |
| US20060153229A1 (en) | System and method for extended distance digital subscriber line based services | |
| CN1095617C (en) | Wide band multi media service system | |
| Schenk et al. | VDSL (Very high bit-rate digital subscriber line)-A bridge and alternative to FTTH | |
| CN103179006A (en) | Power fiber-to-the-home multi-play system | |
| Chen et al. | Architectural alternatives of wireless access through hybrid fiber/coax distribution plant | |
| EP1241832A2 (en) | Method and system for providing internet services | |
| Gupta | Residential broadband technologies for high-speed internet access |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20180528 |