WO2000070891A1

WO2000070891A1 - Wireless telephony over cable networks

Info

Publication number: WO2000070891A1
Application number: PCT/IL2000/000274
Authority: WO
Inventors: Howard Loboda
Original assignee: Onepath Networks Ltd.
Priority date: 1999-05-16
Filing date: 2000-05-14
Publication date: 2000-11-23
Also published as: AU4428200A

Abstract

A method for providing mobile communication services to the home (50) of a subscriber includes coupling mobile communication signals into a broadband cable network (28). The signals are conveyed over at least a portion of the cable network to a transceiver (60) inside the home, which transmits the signals to a mobile telephone (62) in the home.

Description

WO 00/70891 PCTtILOO/00274

WIRELESS TELEPHONY OVER CABLE NETWORKS

FIELD OF THE INVENTION

The present invention relates generally to telecommunication systems, and specifically to systems offering mobile services, including wireless telephony and data communications.

BACKGROUND OF THE INVENTION

Although long-distance telephone service has long since been opened to competition, local loop (or subscriber loop) service is still largely a monopoly held by local telephone companies. Alternative, wireless service is offered widely by cellular telephone networks and, more recently, by personal communication services (PCS) networks. But these services cannot effectively compete with or substitute for wired local loop service in the home and small business market due to inadequate Quality of Service (QoS), poor coverage, limited capacity and dropped call handoffs. There is also growing concern as to the health effects of high-power microwave radiation emitted by cellular telephones and base stations. Cable television operators and new multi-service (or "convergence") service providers are exploring the possibility of moving into the local loop access market, by using their existing broadband HFC (hybrid fiber/coax) infrastructure of fiberoptic and coaxial cable to carry telephone signals into residential neighborhoods. Various methods are under consideration for this purpose, including "broadband telephony," in which telephone signals are modulated onto a radio frequency (RF) cable carrier frequency. Another alternative is Internet (or TCP/IP) telephony, in which voice signals are carried as digital packets over a data network, which can include both twisted pair and broadband networks.

There are practical and economic problems, however, with all of these schemes for wiring home telephone lines into the television cable system. For this reason, cable operators have instead been considering and beginning to adopt cable-to-wireless solutions, in which their HFC infrastructure is used to serve a network of local, short-range cellular or PCS transceivers.

For example, Sanders, a division of the Lockheed Martin Corporation, offers a PCS-over-cable system for deployment of wireless service over HFC networks. A headend control unit is coupled to a base transceiver station (BTS) of a PCS network and converts radio frequency (RF) signals put out by the BTS to an unused cable TV frequency for transmission over the HFC network. The signals travel over the network to multiple, remote RF heads, or repeaters, which are typically located on utility poles outside subscribers' homes. Each such repeater converts the signals back to the original radio frequency and transmits them over the air with a RF power output of one to a few watts, covering a range of several hundred meters. The repeaters also carry reverse-link signals back from the subscribers to the BTS.

The PCS-over-cable system has the advantages of enabling widespread PCS and cellular coverage without the necessity of large, unsightly antenna towers. Since the headend control unit can determine which of the repeaters is serving any particular subscriber during a given call, this information can be used to charge the subscriber at a graduated rate depending on location. The cellular or PCS operator can then compete in the local loop market, by offering a lower price when the subscriber is in the home neighborhood and a higher rate elsewhere. (There is no ready way to determine, however, whether the subscriber is in his or her own home, or elsewhere in the neighborhood.) Subscribers using this service can be reached at the same telephone number wherever they are. Because the repeater is still outdoors and some distance away from the home, however, the QoS of PCS-over-cable systems can fluctuate below the level of the wired local loop. A further disadvantage of this approach is that the PCS signals take away bandwidth (or channel capacity) from the CAIN provider. In order to minimize this bandwidth loss, extra processing of the PCS signals has to take place, in particular signal compression - adding both cost and complexity to the system.

Another wireless telephony-over-cable solution is disclosed in U.S. Patent 5,381,459, which is incorporated herein by reference. This patent describes a system for distributing remote telephone traffic between a base station and a remote antenna site over a cable television network. The base station digitizes and time-compresses outbound telephone signals, and modulates them onto a subcarrier transmitted over the cable network. A plurality of remote transmitters connected to the cable network rebroadcast the signals to wireless telephones operating within their cellular areas. Inbound voice signals are modulated and treated in similar fashion. Similarly, U.S. Patent 5,867,763, which is incorporated herein by reference, describes integration of a personal communication system (PCS) with a cable television plant. A set of radio antenna devices (RADs) are connected to the cable plant and provide frequency conversion and power control of signals received from the cable plant for wireless transmission to remote units, as well as of signals from the remote units for transmission back to the cable plant. Each RAD can operate as either an element of a distributed antenna or as a cellular base station sector unto itself. The architecture of this system is adapted in particular for Code Division Multiple Access (CDMA) communications and exploits certain advantageous features of CDMA.

U.S. Patent 5,699,176, which is incorporated herein by reference, describes an upgradable fiber-coax network, in which optical fibers are deployed alongside the existing coax lines and are used to feed wireless (cellular or PCS) microcells. The optical fibers extend from fiber-coax distribution nodes in the existing network, out to remote optic network units, which are co-located with line extender amplifiers (LEAs) of the coax network. The fiber-microcell network that is created in this way overlays the fiber-coax network and provides wireless services to subscribers within a geographic region of the microcell, typically a 300 meter radius. This radius is supposed to coincide with the spacing of the LEAs.

An alternative solution is combined cellular/ cordless, one-number service, as described, for example, in U.S. Patent 5,675,629, which is incorporated herein by reference. Some cellular network operators, such as Southwestern Bell Mobile Systems, are now offering this service. The subscriber's cellular telephone serves both for receiving mobile calls and as a cordless handset for use with a "personal base station" in the subscriber's home. When the subscriber is at home, and off-line from the cellular system, calls placed to the subscriber's number are automatically routed through the public switched telephone network (PSTN) to the personal base station and transmitted to the handset at the standard 800 MHz cellular frequency. When the subscriber is outside the range of the personal base station, calls are routed through the mobile network. Because this solution is dependent on the PSTN, it is not useful to cable television operators or other alternative service providers not wishing to be dependent upon the local PSTN and local loop twisted pair connections, and to pay the attendant leasing costs. SUMMARY OF THE INVENTION

It is an object of some aspects of the present invention to provide methods and apparatus to support diversified subscriber services, particularly telephone service, over cable television and other broadband_. networks.

It is a further object of some aspects of the present invention to provide improved methods and apparatus for bringing mobile communication services into the home.

It is still a further object of some aspects of the present invention to provide methods and apparatus that enable mobile communications services to be offered with improved quality of service and reduced radiation levels.

It is yet a further object of some aspects of the present invention to enable mobile communications signals to be transmitted over broadband networks in compliance with existing standards and with minimal additions to and modifications of existing signal processing hardware and software. It is a particular object of these aspects of the present invention to make use of existing coax drop cables to the home.

It is an additional object of some aspects of the present invention to enable mobile coiTimuriications service providers to track use of their services by subscribers in a manner that allows new modes of service and billing for such service, which are competitive with existing local loop service. In preferred embodiments of the present invention, mobile telephone signals are conveyed to subscriber premises over a broadband communications network, such as a fiberoptic network or a suitably modified hybrid fiber/coax (HFC) cable network. Typically, although not necessarily, the premises is the subscriber's home, and the HFC network belongs to a cable television or multi-service operator serving the home. The telephone signals preferably comprise cellular and/or PCS signals. These signals are split out of the cable to a micro-repeater on the premises, comprising a transceiver which transmits the signals at a suitable radio frequency (RF) to communicate with the subscriber's cellular or PCS mobile telephone.

The subscriber is thus afforded the convenience of one-number service, whether at home or outside, and the cable operator is able to exploit existing HFC infrastructure to offer a wider range of services and compete in the local loop telephone market. Because the micro-repeater is on the subscriber premises, the quality of service is consistently comparable to wired telephone service, and the power levels of microwave radiation emitted by the micro-repeater and the mobile telephone can be kept to a minimum, preferably under 10 dBm (10 mW), and most preferably about 0 dBm (1 mW).

There is therefore provided, in accordance with a preferred embodiment of the present invention, a method for providing mobile communication services to the home of a subscriber, including: coupling mobile communication signals into a broadband cable network; conveying the signals over at least a portion of the cable network to a transceiver inside the home; and transmitting the signals using the transceiver to a mobile telephone in the home.

Preferably, the mobile corrimunication signals include cellular signals or, alternatively or additionally, personal communication service (PCS) signals. Preferably, the home is located inside a given cell of a wireless communication network in which the network fransmits signals to mobile telephones at a first frequency, and transmitting the signals using the transceiver includes transmitting signals at a second frequency. Most preferably, the second frequency is a frequency at which the network transmits signals to mobile telephones in another cell, adjacent to the given cell.

Preferably, coupling the mobile communication signals includes receiving radio frequency (RF) signals from a base transceiver station belonging to a wireless communications network, wherein coupling the mobile communication signals includes modulating an optical carrier wave in an optical fiber belonging to the cable network responsive to the RF signals. Most preferably, modulating the optical carrier wave includes modulating at the radio frequency of the base transceiver station. Alternatively, modulating the optical carrier wave includes converting the frequency of the signals received from the base transceiver station, wherein conveying the signals includes conveying a pilot frequency signal indicative of the frequency of the signals received from the base transceiver station, and wherein transmitting the signals in the home includes reconverting the signals for transmission at the radio frequency of the base transceiver station using the pilot signal frequency. Preferably, the base transceiver station also transmits the RF signals over the air, substantially independently of the conveyance of the signals over the cable network. In a preferred embodiment, conveying the signals includes conveying signals over optical fiber to a termination of the fiber in the home, and coupling the mobile communication signals includes coupling signals to a head end of the broadband cable network. In another preferred embodiment coupling the mobile communication signals includes overlaying signals on a cable between a line extender amplifier of the cable network and the home, wherein coupling the mobile communication signals includes receiving radio frequency signals, transmitted over the air, at an off-air repeater coupled to overlay the signals on the cable. In still another preferred embodiment, coupling the signals includes coupling signals to a private cable network serving a group of homes.

Preferably, transmitting the signals includes transmitting RF signals with an emitted power level below about 10 mW, and most preferably with an emitted power level of about 1 mW. Preferably, conveying the signals to the transceiver includes splitting the communication signals out of entertainment program signals that are conveyed to the home simultaneously over the cable network, wherein splitting the signals includes using a substantially passive splitter circuit.

Further preferably, conveying the signals to the transceiver includes conveying signals substantially without reliance on local loop access of a public switched telephone network.

Preferably, the method includes receiving reverse link signals from the mobile telephone using the transceiver and conveying the signals back over the cable network in a reverse direction, wherein conveying the signals back over the cable network includes controlling a gain of the signals conveyed in the reverse direction responsive to a level of the signals conveyed over the network to the transceiver in the home.

Further preferably, transmitting the signals includes automatically controlling a gain of transmission responsive to a level of the signals conveyed over the cable network.

There is also provided, in accordance with a preferred embodiment of the present invention, a system for providing mobile communication services to the home of a subscriber, including: a signal converter, which couples communication signals from a base transceiver station (BTS) of a mobile communication network into a cable belonging to a broadband cable network i-rifrastructure, such that the signals are conveyed over the cable infrastructure to the home; and a micro-repeater in the home, including a transceiver, which receives the signals and transmits them over the air to a.mobile telephone in the home. Preferably, the signal converter receives radio frequency (RF) signals from the BTS, which belongs to a wireless communications network, wherein the signal converter, responsive to the RF signals, modulates an optical carrier wave in an optical fiber belonging to the cable infrastructure. Preferably, the signal converter modulates the optical carrier wave at the radio frequency of the BTS. Alternatively, the signal converter converts the frequency of the signals received from the BTS and then modulates the optical carrier wave at the converted frequency, wherein the signal converter provides a pilot frequency signal indicative of a transmission frequency of the BTS, and wherein the micro-repeater reconverts the signals for transmission at the radio frequency of the BTS using the pilot signal frequency.

Preferably, the BTS also transmits the RF signals over the air, substantially independently of the conveyance of the signals over the cable infrastructure.

Preferably, the system includes a splitter, which separates the communication signals from entertainment program signals that are conveyed to the home simultaneously over the cable infrastructure, whereby the micro-repeater receives the communication signals. Most preferably, the splitter includes a passive splitter. In a preferred embodiment, the signal converter couples the mobile communication signals to a head end of the broadband cable network.

In another preferred embodiment, the signal converter includes an overlay combiner, which overlays the mobile communication signals on a cable between a line extender amplifier of the cable network and the home. Preferably, the overlay combiner includes an off-air repeater, which receives radio frequency signals, transmitted over the air, so as to overlay the signals on the cable.

Preferably, the signals are conveyed to the home over the cable infrastructure substantially without reliance on local loop access of a public switched telephone network.

There is further provided, in accordance with a preferred embodiment of the present invention, a micro-repeater for transmitting and receiving mobile communication signals in the home of a subscriber, including: a transceiver, which receives communication signals over a cable from a base transceiver station (BTS) of a mobile coirimunication network; and an antenna, which is driven by the transceiver to transmit the signals with an emitted radio frequency (RF) power below 10 mW. Preferably, the emitted RF power is about 1 mW.

Preferably, the transceiver is coupled to receive the signals from the base transceiver station over a cable entertainment infraslxucture. Further preferably, the micro-repeater includes a splitter, which separates the communication signals from entertainment program signals that are conveyed to the home simultaneously over the cable infrastructure, whereby the communication signals are conveyed to the transceiver.

In a preferred embodiment, the signals are conveyed over the cable infrastructure at a converted frequency, and the micro-repeater includes a frequency converter, which converts the signals from the converted frequency to the radio frequency for transmission to the mobile telephone. Preferably, the mobile communication signals include cellular signals or, alternatively or additionally, personal communications service signals.

Preferably, the transceiver receives the communication signals substantially without reliance on local loop access of a public switched telephone network.

Preferably, the transceiver receives reverse link signals from the mobile telephone and conveys the reverse link signals back to the BTS. Most preferably, the transceiver includes a gain control circuit, which controls a gain of the reverse link signals conveyed back to the BTS responsive to an amplitude of the signals received from the BTS.

In a preferred embodiment the transceiver includes an automatic gain control circuit, which automatically controls a gain of transmission of the signals by the antenna responsive to a level of the signals conveyed over the cable.

There is moreover provided, in accordance with a preferred embodiment of the present invention, a method for providing data services over a broadband cable network, including: providing first and second frequency bands for communication over the network; assigning the first band to a first content provider; and assigning the second band to a second content provider. In a preferred embodiment, the first and second content providers provide competing services to a subscriber of the cable network, wherein when the subscriber chooses to receive services from the second content provider, signals in the second band are converted to the frequency of the first band for reception of the signals in the subscriber's home. Preferably, the first frequency band is in a frequency range belonging to direct satellite broadcast (DBS).

There is additionally provided, in accordance with a preferred embodiment of the present invention, a method for providing mobile communication services to a subscriber having a mobile telephone, including: transmitting mobile communication signals from a base station over the air; coupling the mobile communication signals into a broadband cable network; conveying the signals over the cable network for transmission by a transceiver inside a home of the subscriber; determining whether the mobile telephone is receiving the signals from the transceiver or over the air from the base station; and charging the subscriber for use of the cornmunication services at a first rate when the signals are received from the transceiver and at a second rate, different from the first rate, when the signals are received over the air from the base station.

Preferably, the signals from the transceiver or over the air from the base station includes determining whether a frequency channel used by the mobile telephone belongs to the transceiver or to the base station. Further preferably, the method includes determining that the subscriber is in the home when the mobile telephone is receiving the signal from the transceiver.

The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram that schematically illustrates a broadband corrimunications network configured to convey telephone signals to a home, in accordance with a preferred embodiment of the present invention; Fig. 2 is a schematic, pictorial diagram illustrating the distribution of wireless cornmunication cells in the network of Fig. 1 , in accordance with a preferred embodiment of the present invention; W

Fig. 3A is a block diagram that schematically illustrates a hybrid fiber/coax (HFC) network configured to convey telephone signals to a home, in accordance with another preferred embodiment of the present invention;

Fig. 3B is a block diagram that schematically illustrates a private cable network configured to convey telephone signals to a home, in accordance with still another preferred embodiment of the present invention;

Fig. 4 is a graph that schematically illustrates a spectrum of signals conveyed over a broadband network, in accordance with a preferred embodiment of the present invention;

Fig. 5 is a graph that schematically illustrates a spectrum of signals conveyed over a broadband network, in accordance with another preferred embodiment of the present invention;

Fig. 6 is a schematic circuit diagram of a splitter, used to distribute signals in a home served by a broadband network, in accordance with a preferred embodiment of the present invention; Fig. 7 is a schematic circuit diagram of a micro-repeater, used to transmit and receive mobile telephone signals in a home, in accordance with a preferred embodiment of the present invention;

Fig. 8 is a graph that schematically illustrates a spectrum of signals conveyed over a broadband network, in accordance with another preferred embodiment of the present invention; and

Fig. 9 is a schematic circuit diagram of a micro-repeater, used to transmit and receive mobile telephone signals in a home served by a broadband network, in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 is a block diagram that schematically illustrates a system 20 for transmission of telephone signals over a broadband network, typically a hybrid fiber/coax (HFC) cable network, in accordance with a preferred embodiment of the present invention. A base transceiver station (BTS) 22, belonging to a mobile communications network 24, is coupled to transmit and receive telephone signals. The signals are typically transmitted over the air, via a conventional cellular antenna 26, as is known in the art, although such transmission is itself not material to the present invention. Preferably, the signals comprise cellular band signals, typically in the 800-900 MHz range, and/or PCS signals in the 1800-1900 MHz range. A head end converter 30 interfaces BTS 22 to fiberoptic cables 28, whereby the telephone signals are converted to optical form and conveyed between the BTS and optical nodes 32, 34, 36, along with cable television (CAIN) and other signals provided from a CATN head end 21. Each of the optical nodes serves a number of subscribers, who receive not only the telephone signals, but also cable television and other signals normally carried over cables 28. To reach these subscribers, the signals received at node 36, for example, are converted to radio frequency (RF) electrical signals. These signals are typically conveyed to the subscribers over coaxial cable 44, following amplification by line extension amplifiers (LEAs) 38, 40, 42 (which can be incorporated into optical node 36). Cable 44 reaches the homes of the subscribers, such as a home 50 shown in Fig. 1. It carries both one-way traffic, such as television programming, and bi-directional traffic from the home, such as cable modem signals and telephone signals on the reverse link back to BTS 22 via converter 30.

At the end of cable 44 in home 50, a splitter 52 divides signal from the cable among appropriate receivers in the home, and also combines the reverse-link signals for transmission back over the cable. As is known in the art, the splitter passes the received signals to a cable television set-top box 54, or to a suitably-configured television set 56, as well as to a cable modem 58. In addition, as provided by preferred embodiments of the present invention, the splitter passes the telephone signals on the cable to and from a micro-repeater 60 in home 50, which communicates with a cellular or PCS mobile telephone 62, as described further hereinbelow. When telephone 62 is at any substantial distance outside home 50, it communicates with mobile network 24 via antenna 26 or any other suitable antenna (including micro-repeaters in other homes and business premises). BTS 22 identifies when telephone 62 is communicating with the subscriber's own micro-repeater 60 and notifies mobile network 24 accordingly for billing purposes.

System 20 is superior to cable telephony systems known in the art, such as the Sanders system described in the Background of the Invention, in that micro-repeater 60 is configured and installed to transmit the telephone signals over the air inside home 50. In this configuration, the micro-repeater is able to give full coverage of the entire home, with excellent quality of service, at a RF power level of only about 0 dBm (1 mW of transmitted power). Telephone 62 will similarly operate at its miriimum output power while in the home, so that exposure of the telephone user and other residents to the cellular or PCS-band radiation is minimized, and battery life is maximized.

System 20 thus gives subscribers ubiquitous one-number service, which can be offered at a price competitive with wired PSTN service on the local loop, in a manner that is totally independent of the PSTN. Furthermore, the high quality of service (QoS) achieved inside the home, thanks to the use of the micro-repeater, will encourage subscribers to be more reliant on their wireless phones for business, leisure and in-home use. Thus, preferred embodiments of the present invention offer significant, unexpected advantages relative to solutions known in the art, in which the repeater is positioned outside the home and indiscriminately serves multiple indoor and outdoor areas. Further aspects of micro-repeater 60 are described hereinbelow.

Fig. 2 is a schematic, pictorial illustration showing a distribution of homes 50 served by system 20, useful in understanding further advantages of preferred embodiments of the present invention in providing efficient, high-quality wireless communication services. The homes pictured in Fig. 2 lie within a macrocell 53 served by BTS 22 and antenna 26, as is known in the art. Independent of this macrocell, each home is served by its own sub-cell, created by the micro-repeater 60 in each of the homes, and referred to herein as a "pico-cell." The pico-cells in Fig. 2 are represented by dashed circles inside homes 50, and it is thus seen that one group of homes is served by pico-cells 51, another by pico-cells 55, and still another by pico-cells 57. These pico-cells are preferably designed to cover substantially only indoor areas, along with immediately-adjoining areas of the respective homes and residences.

Typically, antenna 26 broadcasts signals to macrocell 53 at one or several of the frequencies allocated to wireless network 24. Other, neighboring macrocells (not shown in the figure) are associated with other allocated frequencies. In the design of the cellular network and layout of the cells, frequencies must be carefully assigned so that, in general, neighboring cells do not use the same frequencies. This limitation as to the allocation of frequencies ultimately limits the subscriber channel capacity that is available in each cell and, hence, the number of subscribers who can use network 24 at any given time. Pico-cells 51, 55, 57 effectively increase this capacity, since they allow frequencies assigned to other, neighboring macrocells to be re-used inside the area of macrocell 53. Each pico-cell need be assigned only one or a few of the available cornmunication channels in order to serve a limited number of homes and subscribers. The frequency and/or channel over which a particular telephone 62 is operating at any particular time is preferably used in order to determine whether that telephone is operating in its home pico-cell or out of the home. In addition, the particular phone can be identified and associated with a particular frequency or cell. This frequency/channel/home differentiation allows the cellular network operator to vary the billing rate for air time used by the subscriber depending on the subscriber's location, wherein a particularly low rate is charged in the home pico-cell (and at certain times of the day/night or week) in order to compete with wired local loop service. Several subscribers in the same home may, of course, be served by the same pico-cell and micro-repeater 60. Other subscribers of the same mobile network can also make calls via the micro-repeater in home 50, and the network operator has the option of charging for these calls at the full mobile rate, or offering special, promotional neighborhood or family rates. Other, foreign cellular subscribers of competing networks can optionally be blocked out.

The ability to precisely track the subscriber's calls and calling habits can also be advantageous in early detection of mobile telephone fraud, for example, when telephone 62 is stolen and is used to make a call from an unexpected location and/or at an unexpected time. This tracking capability may also be useful in deterrriining the exact location of a subscriber making an emergency "911" call, without having to triangulate the subscriber's position among several different cellular base stations, as is currently known in the art. A further advantage of the architecture illustrated by Fig. 2 is that it focuses the wireless coverage offered by system 20 tightly in the areas where the coverage is most desired - inside homes 50. Systems such as that described in the above-mentioned U.S. Patent 5,699,176, in which the wireless repeaters are placed outside the homes and serve an extended area, do not offer this advantage. Such outdoor micro-repeaters cannot readily re-use the frequencies of neighboring macrocells, due to the likelihood of inter-cell interference. Furthermore, the line extender amplifiers (LEAs) of typical HFC networks, which are the locations at which the ' 176 patent proposes to place the repeaters, are generally not evenly spaced (in contradiction to the situation illustrated, for example, in Fig. 11 of that patent), so that coverage inside the homes will be uneven. These problems are solved by the present invention.

Fig. 3A is a block diagram that schematically illustrates a system 64 for transmission of telephone signals over a cable network, in accordance with another preferred embodiment of the present invention. System 20 (Fig. 1) requires an infrastructure capable of carrying broadband communications signals all the way from head end 21 to homes 50, which is not available in most existing cable IN networks. Therefore, in system 64, the cellular and/or PCS signals fed to micro-repeater 60 are overlaid onto cable 44 by an overlay combiner 68 only at a point between line extender amplifier 42 and home 50.

Various approaches may be used to convey mobile communications signals between BTS 22 and overlay combiner 68. In the configuration shown in Fig. 3, an off-air repeater 66 receives signals from donor antenna 26 and transmits signals to the donor antenna over the air. This approach has the advantage that it requires minimal additional cabling. Furthermore, unlike off-air repeaters known in the art, which typically provide repeater service for all of the competing cellular services in a given area (even if installed and maintained by only one of the cellular service providers), repeater 66 serves only the service provider who has contracted to serve home 50.

Alternatively, signals from BTS 22 may be conveyed to overlay combiner 68 via a fiberoptic network, such as that described in the above-mentioned U.S. Patent 5,699,176, or over a wired connection (coax or twisted pair) to a nearby microcell base station or repeater.

Fig. 3B is a block diagram that illustrates a system 65 for combining wireless telephone services with a private cable network, in accordance with still another preferred embodiment of the present invention. Such private networks, also known as small master antenna television (SMATN) networks, commonly exist in small communities, campuses and large apartment buildings. They typically comprise a mini-head end 67, equipped with one or more suitable antennas, and cabling 44. Foxcom Inc. (Princeton, New Jersey ) offers a system of this type for apartment buildings, known as the SDTV system, in which signals are carried between the mini-head end and individual apartments by a hybrid optical fiber and coax drop cable network. The SDTV system is further described in U.S. Patent Applications 08/886,695 and 08/899,452, which have a common applicant with the present patent application and are incorporated herein by reference. In system 65, wireless communications signals are received and transmitted by off-air repeater 66, and are combined with the television signals on cabling 44 for connection to the micro-repeaters (not shown) in homes 50. Alternatively, microcells fed by twisted pair or an optical fiber backhaul link can also be used to transmit the BTS signals to the property. Fig. 4 is a graph that schematically illustrates a spectrum 70 of signals conveyed via system 20, in accordance with a preferred embodiment of the present invention. The spectrum includes a cable modem operating band 72, between 5 and 40 MHz, and a cable television band 74, from 50 to 750 MHz, as well as a high-frequency band 76, which carries, for example, digital DBS (direct satellite broadcast) signals between 950 and 1450 MHz. There is an optional additional high-frequency (DBS II) band 77 between 1550 and 2050 MHz, whose potential use is described further hereinbelow. Most cable networks at present are not configured to carry signals above the 750 MHz limit frequency of CAIN band 74, but it is likely that the broadband cable coverage illustrated in Fig. 4 will become increasingly available in the near future.

A band 78 of cellular telephone signals to and from BTS 22, between 800 and 900 MHz, fits between CATN band 74 and DBS band 76. An optional PCS band 80, between 1800 and 1900 MHz, must be overlaid on DBS II band 77, in place of entertainment channels that could be carried if this band is used. Thus, in this embodiment, the RF signals output by BTS 22 in the cellular or PCS band are converted directly by converter 30 into optical signals modulated at the same frequencies, and vice versa. Fiberoptic devices and cable operating at these frequencies are known in the art. For example, the RFIBER system, produced by Foxcom Wireless Ltd. (Lod, Israel), offers this sort of functionality. Difficulty may arise, however, at the level of amplifiers 38, 40 and 42 and of coaxial cable 44, which are not commonly designed to operate at frequencies much above the high end of cable TV band 74. Therefore, node 36 is preferably located as close as feasible to home 50, and serves a small number of homes (typically no more than 20-40 homes) so as to minimize attenuation of the signals over cable 44. Locating the optical node close to the home also makes more bandwidth available to the subscriber for advanced data services, as well as increasing QoS, reducing the number of calls inadvertently dropped, and generally improving overall system reliability. Most preferably, amplifier 42 and cable 44 are replaced by optical fiber all the way to the home, as has been widely proposed, for example, in FTTH (fiber to the home) and POΝ (passive optical networks). Alternatively or additionally, each amplifier 38, 40 and 42 comprises a bank of two or more amplifiers (not shown), including a low-band RF amplifier for cable TV band 74 and a high-frequency amplifier for DBS bands 76 and 77, which also amplifies the signals in cellular band 78 and PCS band 80. It is noted, incidentally, that certain regulatory trends may dictate to CATN providers that they make their infrastructure available to other competitive providers (much as local telephony companies are required to do today). In this regard, the capacity to carry DBS I band 76 and DBS II band 77 (or any other services) is a business asset. The DBS I band corresponds to the frequency range of current direct satellite television broadcasting, and may be used by the CAIN provider to offer additional programming, beyond that in CATN band 74. Alternatively, this band may be leased to a competing provider. The DBS II band may be leased to yet another competing provider, who can use the band to carry signals upconverted from the normal DBS I range, for example. Subscribers may then be offered the choice of purchasing program services from either or both of the DBS I and DBS II providers. Several competing providers may thus share the same fiberoptic infrastructure.

In this regard, Fig. 5 is a graph that schematically illustrates a spectrum 71 of signals conveyed via system 20, in accordance with another preferred embodiment of the present invention. Spectrum 71 is substantially similar to spectrum 70, shown in Fig. 4, except that PCS band 82 is upconverted at the head end of the network, roughly to the 2100-2200 MHz range, in order to avoid overlapping with DBS II band 77 (which is thus kept open for cable programming). The PCS signals are then downconverted to the original 1800-1900 MHz band in the home.

Alternatively, the PCS band is downconverted at the head end to the 1450-1550 MHz range, so as to fit into a "notch" 84 between the DBS I and DBS II bands. The PCS signals are then upconverted in the home.

Fig. 6 is a block diagram that schematically illustrates splitter 52 in home 50, in accordance with a preferred embodiment of the present invention. This splitter is designed for use with signal spectrum 70 or 71, shown in the preceding figures. Because of the frequency separation of cable bands 72 and 74 (and optionally of DBS I band 76) from wireless bands 78 and 80 (or 82), the splitter is of simple construction, preferably using passive components. A diplexer 86 separates the wireless signals from the cable signals by means of appropriate bandpass filtering. The cable signals preferably pass through a notch filter 88, which traps the wireless frequencies, so that they do not interfere with CATN reception. A further multiplexer 89 splits the cable signals among cable television 56, set top box 54 and modem 58, as appropriate. Fig. 7 is a schematic circuit diagram illustrating micro-repeater 60, as designed for use in conjunction with signal spectrum 70, in accordance with a preferred embodiment of the present invention. A diplexer 90 passes forward-link telephone signals received from splitter 52 to a RF power amplifier 92. The amplified signals are conveyed via another diplexer 96 for transmission by an antenna 98. On the reverse link, signals received from telephone 62 (or any other compatible cellular or PCS telephone in home 50 or possibly in its immediate vicinity) pass through diplexer 96 to a receiver amplifier 94. These signals are conveyed via diplexer 90 back to splitter 52, to be returned to converter 30 (Fig. 1). Although for simplicity of illustration, only the most basic elements of micro-repeater 60 are shown in Fig. 3, it will be appreciated that the micro-repeater is fundamentally different from local base stations and repeaters known in the art, since it is designed to serve only a single home and to operate at far lower power levels than prior art devices.

Preferably, micro-repeater 60 comprises a local power supply 95, which runs off the AC line in home 50 and provides electrical power to the micro-repeater circuits. Most preferably, the power supply serves to charge a back-up battery 97, for use in case of power failure. Providing power in this manner at the subscriber node reduces network cost and increases reliability. A further advantage of micro-repeater 60, and of system 20 in general, is that they are protocol- transparent, and can work substantially without modification with any cellular or PCS air interface known in the art, such as CDMA, TDMA or AMPS. RF signals received from BTS 22 are converted directly to off-air optical signals, preferably modulated at the RF modulation frequency, and are then converted back to the same RF signals at the micro-repeater. There is no need for protocol conversion or compression. By comparison, broadband/wireless systems known in the art are generally protocol-dependent, such as that described in the above-mentioned U.S. Patent 5,867,763, and/or involve protocol conversions, as described in the above-mentioned U.S. Patent 5,675,629. Such systems require costly digital signal processing and switching hardware, in contrast to the simplicity of micro-repeater 60.

The protocol-transparency of system 20 has several additional advantages. Because the system uses the same signals and protocols both inside home 50 and outdoors, there is less likely to be a problem of dropped calls during handoff between the indoor pico-cell and outdoor macrocell 53 (Fig. 2) than in systems such as that described in the '629 patent. Furthermore, telephone 62 may comprise any available cellular or PCS mobile unit that is compatible with mobile network 24, and no special handset or capabilities are needed. Therefore, the system can be rolled out quickly and at low cost to the consumer.

As shown in Fig. 7, micro-repeater 60 preferably comprises an automatic gain control (AGC) circuit 99, which samples forward-link signals at the output of power amplifier 92. Circuit 99 controls the gain of the power amplifier and, most preferably, of receive amplifier 94, as well, responsive to the signal level. The AGC is set so that no matter how far micro-repeater 60 is from the last line extender amplifier 42 leading to home 50, the power output from antenna 98 is maintained within a constant range, or at some particular value determined by the network operator. Typically, losses due to passive circuit elements, the length of cable 44, differences in frequency response (cellular vs. PCS), and changes in transmission characteristics over the life cycle of the cable plant contribute up to 20 dB of variation in the attenuation of the signals between amplifier 42 and micro-repeater 60, and this attenuation must be compensated for in the signals transmitted inside home 50. This function is performed by AGC circuit 99. Preferably, the AGC circuit is also "ganged" to control reverse-link amplifier 94, so that the signals reaching node 36 (Figs. 1 and 2) from all of homes 50 are of roughly equal amplitudes.

Unlike outdoor macrocells and microcells, the pico-cell in home 50 covers a small, well-defined geographical area, over which the RF signal level received by telephone 62 is constant to vvitiiin a small dynamic range. AGC circuit 99 ensures that this dynamic range is properly maintained. Therefore, the QoS experienced by a user of telephone 62 will be uniformly good throughout the home, comparable to the quality of wired telephone service, and without the variations that are common in outdoor cellular telephone use. Since typically only a single user communicates via micro-repeater 60 at any given time, the user will experience substantially less interference and less noise than occurs in outdoor use, due to the wide dynamic range that macrocells and microcells must normally cover. These benefits apply not only to voice communications, but to wireless data communications, as well.

In addition to the advantages that are specific to the local pico-cell, there is a system-wide advantage that becomes apparent when the combined signals of all of the pico-cell users are statistically summed at the BTS. Since every pico-cell is of a limited dynamic range, the entire combined signal is by necessity also of a correspondingly-reduced dynamic range, making the BTS requirements less stringent and increasing the system QoS margins. Fig. 8 is a graph that schematically illustrates a spectrum 100 of signals conveyed via system 20, in accordance with another preferred embodiment of the present invention. Spectrum 100 is characteristic of a conventional cable television network, so that it includes only cable modem operating band 72 and cable TV band 74, without the high-frequency DBS bands shown in Figs. 4 and 5. In consequence, the cellular and/or PCS telephone signals output by BTS 22 cannot be directly modulated onto an optical carrier as in the preceding embodiment, but must rather be downconverted by converter 30 to a frequency band 102 in the cable TV band. Band 102 thus displaces one or more cable TV channels. Preferably, converter 30 also adds a pilot signal 104, at a frequency that is indicative of the RF transmission frequency of BTS 22. The purpose of the pilot signal is described ftirther hereinbelow.

Fig. 9 is a schematic circuit diagram illustrating a micro-repeater 120, designed for use in conjunction with signal spectrum 100, in accordance with a preferred embodiment of the present invention. Micro-repeater 120 is used in place of micro-repeater 60, as shown in Fig. 1, when the telephone signals have been downconverted for transmission via system 20. Thus, micro-repeater 120 needs to have upconversion and downconversion capabilities, but the transceiver portion of the two micro-repeaters (amplifiers 92 and 94) are substantially similar. In order to save the cost of diplexer 96, micro-repeater 120 instead has a separate transmit antenna 126 and receive antenna 128. Telephone signals received from splitter 52 are passed to a diplexer 122, and from there to a filter 124 and a mixer 110 for upconversion. In order to generate the proper upconversion frequency, a phase-locked loop 114 locks onto the frequency of pilot signal 104. This frequency is used to drive a local oscillator 108, which provides the proper frequency to mixer 110. Similarly, reverse-link RF signals are downconverted by a mixer 112 and are then filtered by a filter 106 before being conveyed by diplexer 122 back to splitter 52. Thus, using spectrum 100 and micro-repeater 120, system 20 can be made to carry high-frequency cellular and PCS telephone signals, substantially without modification to the conventional HFC cable j-rifrastructure.

Although the embodiment illustrated by Figs. 8 and 9 uses a simple analog up- and downconversion scheme, those skilled in the art will appreciate that a wide variety of different modulation schemes may be used to convert the signals from BTS 22 for transmission over the HFC network. For example, various digital processing schemes may be used for this purpose, as long as micro-repeater is equipped with a digital signal processor or other hardware necessary for converting the digital signals back to the proper RF form.

More generally, although preferred embodiments are described hereinabove with reference to a cellular or PCS mobile communications network and base transceiver station, which is coupled to cable television HFC infrastructure, it will be appreciated that the principles of the present invention may similarly be applied to provide local loop communications services in conjunction with other types of cornmunication networks and infrastructures. For example, these principles may be applied to networks that will offer "third generation" services, such as high-speed data communications and interactive, digital video. It will be thus be understood that the preferred embodiments described above are cited by way of example, and the full scope of the invention is limited only by the claims.

Claims

1. A method for providing mobile communication services to the home of a subscriber, comprising: coupling mobile communication signals into a broadband cable network; conveying the signals over at least a portion of the cable network to a transceiver inside the home; and transmitting the signals using the transceiver to a mobile telephone in the home.

2. A method according to claim 1 , wherein the mobile communication signals comprise cellular signals.

3. A method according to claim 2, wherein the mobile communication signals comprise personal communication service (PCS) signals.

4. A method according to claim 2, wherein the home is located inside a given cell of a wireless communication network in which the network transmits signals to mobile telephones at a first frequency, and wherein transmitting the signals using the transceiver comprises transmitting signals at a second frequency.

5. A method according to claim 4, wherein the second frequency is a frequency at which the network transmits signals to mobile telephones in another cell, adjacent to the given cell.

6. A method according to any of the preceding claims, wherein coupling the mobile communication signals comprises receiving radio frequency (RF) signals from a base transceiver station belonging to a wireless communications network.

7. A method according to claim 6, wherein coupling the mobile communication signals comprises modulating an optical carrier wave in an optical fiber belonging to the cable network responsive to the RF signals.

8. A method according to claim 7, wherein modulating the optical carrier wave comprises modulating at the radio frequency of the base transceiver station.

9. A method according to claim 7, wherein modulating the optical carrier wave comprises converting the frequency of the signals received from the base transceiver station.

10. A method according to claim 9, wherein conveying the signals comprises conveying a pilot frequency signal indicative of the frequency of the signals received from the base transceiver station, and wherein transmitting the signals in the home comprises reconverting the signals for transmission at the radio frequency of the base transceiver station using the pilot signal frequency.

11. A method according to claim 6, wherein the base transceiver station also transmits the RF signals over the air, substantially independently of the conveyance of the signals over the cable network.

12. A method according to claim 6, wherein conveying the signals comprises conveying signals over optical fiber to a termination of the fiber in the home.

13. A method according to any of claims 1-5, wherein coupling the mobile communication signals comprises coupling signals to a head end of the broadband cable network.

14. A method according to any of claims 1-5, wherein coupling the mobile communication signals comprises overlaying signals on a cable between a line extender amplifier of the cable network and the home.

15. A method according to claim 14, wherein coupling the mobile communication signals comprises receiving radio frequency signals, transmitted over the air, at an off-air repeater coupled to overlay the signals on the cable.

16. A method according to any of claims 1-5, wherein coupling the signals comprises coupling signals to a private cable network serving a group of homes.

17. A method according to any of claims 1-5, wherein transmitting the signals comprises transmitting RF signals with an emitted power level below about 10 mW.

18. A method according to claim 17, wherein transmitting the RF signals comprises transmitting RF signals with an emitted power level of about 1 mW.

19. A method according to any of claims 1-5, wherein conveying the signals to the transceiver comprises splitting the cornmunication signals out of entertainment program signals that are conveyed to the home simultaneously over the cable network.

20. A method according to claim 19, wherein splitting the signals comprises using a substantially passive splitter circuit. WO 00/70891 PCTtILOO/00274

21. A method according to any of claims 1-5, wherein conveying the signals to the transceiver comprises conveying signals substantially without reliance on local loop access of a public switched telephone network.

22. A method according to any of claims 1-5, and comprising receiving reverse link signals from the mobile telephone using the transceiver and conveying the signals back over the cable network in a reverse direction.

23. A method according to claim 22, wherein conveying the signals back over the cable network comprises controlling a gain of the signals conveyed in the reverse direction responsive to a level of the signals conveyed over the network to the transceiver in the home.

24. A method according to any of claims 1-5, wherein transmitting the signals comprises automatically controlling a gain of transmission responsive to a level of the signals conveyed over the cable network.

25. A system for providing mobile coirimunication services to the home of a subscriber, comprising: a signal converter, which couples communication signals from a base transceiver station (BTS) of a mobile communication network into a cable belonging to a broadband cable network irifrastructure, such that the signals are conveyed over the cable infrastructure to the home; and a micro-repeater in the home, comprising a transceiver, which receives the signals and transmits them over the air to a mobile telephone in the home.

26. A system according to claim 25, wherein the mobile communication network comprises a cellular network.

27. A system according to claim 25, wherein the mobile communication network comprises a personal cornmunication service network.

28. A system according to claim 25, wherein the signal converter receives radio frequency (RF) signals from the BTS, which belongs to a wireless communications network.

29. A system according to claim 28, wherein the signal converter, responsive to the RF signals, modulates an optical carrier wave in an optical fiber belonging to the cable infrastructure.

30. A system according to claim 29, wherein the signal converter modulates the optical carrier wave at the radio frequency of the BTS.

31. A system according to claim 29, wherein the signal converter converts the frequency of the signals received from the BTS and then modulates the optical carrier wave at the converted frequency.

32. A system according to claim 31, wherein the signal converter provides a pilot frequency signal indicative of a transmission frequency of the BTS, and wherein the micro-repeater reconverts the signals for transmission at the radio frequency of the BTS using the pilot signal frequency.

33. A system according to claim 29, wherein the BTS also transmits the RF signals over the air, substantially independently of the conveyance of the signals over the cable infrastructure.

34. A system according to any of claims 25-33, and comprising a splitter, which separates the communication signals from entertainment program signals that are conveyed to the home simultaneously over the cable infrastructure, whereby the micro-repeater receives the communication signals.

35. A system according to claim 34, wherein the splitter comprises a passive splitter.

36. A system according to any of claims 25-33, wherein the signal converter couples the mobile communication signals to a head end of the broadband cable network.

37. A system according to any of claims 25-33, wherein the signal converter comprises an overlay combiner, which overlays the mobile coπ-munication signals on a cable between a line extender amplifier of the cable network and the home.

38. A system according to claim 37, wherein the overlay combiner comprises an off-air repeater, which receives radio frequency signals, transmitted over the air, so as to overlay the signals on the cable.

39. A system according to any of claims 25-33, wherein the signals are conveyed to the home over the cable infrastructure substantially without reliance on local loop access of a public switched telephone network.

40. A micro-repeater for transmitting and receiving mobile communication signals in the home of a subscriber, comprising: a transceiver, which receives communication signals over a cable from a base transceiver station (BTS) of a mobile communication network; and an antenna, which is driven by the transceiver to transmit the signals with an emitted radio frequency (RF) power below 10 mW.

41. A micro-repeater according to claim 40, wherein the emitted RF power is about 1 mW.

42. A micro-repeater according to claim 40, wherein the transceiver is coupled to receive the signals from the base transceiver station over a cable entertainment infrastructure.

43. A micro-repeater accordmg to claim 42, and comprising a splitter, which separates the cornmunication signals from entertainment program signals that are conveyed to the home simultaneously over the cable infrastructure, whereby the communication signals are conveyed to the transceiver.

44. A micro-repeater according to claim 42, wherein the signals are conveyed over the cable infrastructure at a converted frequency, and comprising a frequency converter, which converts the signals from the converted frequency to the radio frequency for transmission to the mobile telephone.

45. A micro-repeater according to any of claims 40-44, wherein the mobile communication signals comprise cellular signals.

46. A micro-repeater according to any of claims 40-44, wherein the mobile communication signals comprise personal communications service signals.

47. A micro-repeater according to any of claims 40-44, wherein the transceiver receives the communication signals substantially without reliance on local loop access of a public switched telephone network.

48. A micro-repeater according to any of claims 40-44, wherein the transceiver receives reverse link signals from the mobile telephone and conveys the reverse link signals back to the BTS.

49. A micro-repeater according to claim 48, wherein the transceiver comprises a gain control circuit, which controls a gain of the reverse link signals conveyed back to the BTS responsive to an amplitude of the signals received from the BTS.

50. A micro-repeater according to any of claims 40-44, wherein the transceiver comprises an automatic gain control circuit, which automatically controls a gain of transmission of the signals by the antenna responsive to a level of the signals conveyed over the cable.

51. A method for providing data services over a broadband cable network, comprising: providing first and second frequency bands for communication over the network; assigning the first band to a first content provider; and assigning the second band to a second content provider.

52. A method according to claim 51, wherein the first and second content providers provide competing services to a subscriber of the cable network.

53. A method according to claim 52, wherein when the subscriber chooses to receive services from the second content provider, signals in the second band are converted to the frequency of the first band for reception of the signals in the subscriber's home.

54. A method according to any of claims 51-53, wherein the first frequency band is in a frequency range belonging to direct satellite broadcast (DBS).

55. A method for providing mobile communication services to a subscriber having a mobile telephone, comprising: transmitting mobile communication signals from a base station over the air; coupling the mobile communication signals into a broadband cable network; conveying the signals over the cable network for transmission by a transceiver inside a home of the subscriber; determining whether the mobile telephone is receiving the signals from the transceiver or over the air from the base station; and charging the subscriber for use of the cornmunication services at a first rate when the signals are received from the transceiver and at a second rate, different from the first rate, when the signals are received over the air from the base station.

56. A method according to claim 55, wherein determining whether the mobile telephone has received the signals from the transceiver or over the air from the base station comprises determining whether a frequency channel used by the mobile telephone belongs to the transceiver or to the base station.

57. A method according to claim 55 or 56, and comprising determining that the subscriber is in the home when the mobile telephone is receiving the signal from the transceiver.