WO2001029926A1 - Telecommunication antenna system - Google Patents

Telecommunication antenna system Download PDF

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Publication number
WO2001029926A1
WO2001029926A1 PCT/NZ2000/000205 NZ0000205W WO0129926A1 WO 2001029926 A1 WO2001029926 A1 WO 2001029926A1 NZ 0000205 W NZ0000205 W NZ 0000205W WO 0129926 A1 WO0129926 A1 WO 0129926A1
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WO
WIPO (PCT)
Prior art keywords
antenna
link signals
mobile communication
communication devices
signal
Prior art date
Application number
PCT/NZ2000/000205
Other languages
French (fr)
Inventor
Arthur George Roberts
Original Assignee
Andrew Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Andrew Corporation filed Critical Andrew Corporation
Priority to AU13128/01A priority Critical patent/AU1312801A/en
Publication of WO2001029926A1 publication Critical patent/WO2001029926A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/30—Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array

Definitions

  • the present invention relates to a telecommunication antenna system; a method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices; and a phased array feed network.
  • a conventional cellular telecommunication antenna system is shown in Figure 1 .
  • An antenna 1 is mounted on a mast 2 and connected to a transceiver 3.
  • the antenna 1 has a downtuted radiation pattern 4 which covers a cell 5 on the ground 6.
  • the transceiver 3 transmits down-link signals 7 to mobile communication devices (hereinafter referred to as "mobiles") 8 in the cell 5, and also receives up-link signals 9 from the mobiles 8.
  • the transceiver 3 communicates with a number of mobiles in the cell 5 using a suitable multiple access method. Examples are frequency division multiple access (FDMA), code division multiple access (CDMA), time division multiple access (TDMA) and spatial division multiple access (SDMA).
  • FDMA frequency division multiple access
  • CDMA code division multiple access
  • TDMA time division multiple access
  • SDMA spatial division multiple access
  • FIG. 2 A conventional solution to this problem is illustrated in Figure 2. If sufficient space is available on the mast 2, a second antenna array 10 is mounted below the antenna array 1 , coupled to a respective transceiver 1 1 coupled with a power control system 1 2. The radiation pattern of the array 1 is steered as shown at 1 3 to illuminate an outer cell 14. The radiation pattern 1 5 of the second array 10 is downtuted to illuminate an inner cell (or microcell) 1 6. The power control system 1 2 reduces the signals received and transmitted by antenna array 10 in order to prevent overlap between the two cells.
  • the site shown in Figure 2 is conventionally known as an "umbrella site".
  • An object of the present invention is to address or at least ameliorate the problems of the prior art described above, or at least to provide the public with a useful choice.
  • a telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first transmitter for transmitting first down-link signals; a second transmitter for transmitting second down-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first transmitter, a second signal port coupled to the second transmitter; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element radiates the first down-link signals in an upper beam towards the further of the mobile communication devices, and radiates the second down-link signals in a lower beam towards the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
  • a telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first receiver for receiving first up-link signals; a second receiver for receiving second up-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first receiver, a second signal port coupled to the second receiver, and means for providing a phase shift between up-link signals at the antenna ports and up-link signals at the first and second signal ports, signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element receives the first up-link signals in an upper beam from the further of the mobile communication devices, and receives the second up-link signals in a lower beam from the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
  • a fourth aspect of the invention provides a method of installing a telecommunication antenna system, the method comprising the steps of:
  • the first to fourth aspects of the present invention provide a single antenna array with a multi-beam radiation pattern with relatively downtilted beams.
  • the cell When provided in a cellular system of the type shown in Figure 1 , the cell can be divided into inner and outer cells, each serviced by a respective beam. This increases the number of mobiles that can be serviced in a given area.
  • the antenna elements may have a variety of configurations.
  • the elements may be arranged in a one-dimensional or two dimensional array.
  • the elements are substantially coplanar.
  • At least two of the elements are arranged in use at different heights so as to provide downtilt between the two beams.
  • the elements are arranged in a substantially vertical one-dimensional array.
  • the second and third aspects of the invention relate to a transmitting antenna system and a receiving antenna system respectively.
  • the system can both transmit and receive signals.
  • the means for providing a phase shift typically comprises a plurality of phase shifters, which may be variable phase shifters.
  • the variable phase shifters have relatively movable components which are relatively movable to vary the phase shift.
  • the components may be moved manually.
  • electromechanical means are provided to move the components, and a controller is provided for supplying drive signals to the electromechanical means to adjust the beam angle of the antenna.
  • An example of a phase shift system of this type is given in WO-A-96/1 4670.
  • a phased array feed network including a plurality of antenna ports; a plurality of signal ports; and means for providing a phase shift between signals at the antenna ports and signals at the signal ports, wherein the number of signal ports is less than the number of antenna ports.
  • the fifth aspect of the invention provides a feed network which is specially adapted for use in a multi-beam antenna system according to the second or third aspects of the invention.
  • the feed network In contrast to conventional feed networks where the number of antenna ports is equal to the number of signal ports, the feed network only requires a limited number of signal ports, equal to the number of beams being serviced.
  • the number of antenna ports is a factor of 2 (ie., 4,8, 1 6 etc) .
  • the number of signal ports is two.
  • the network has two signal ports and eight antenna ports.
  • a single-beam antenna system is shown in Figure 1 3 as a comparative example.
  • An antenna 1 10 radiates down-link signals in a beam 1 1 1 .
  • the antenna 1 10 has a single input port 1 1 3 for receiving down-link signals.
  • a pair of modulators 1 14, 1 1 5 modulate carrier signals at different frequencies fi and h respectively and input the modulated signals to a combiner 1 1 2.
  • a problem with the arrangement of Figure 1 2 is that the combiner 1 1 2 introduces a significant signal loss into the system.
  • a sixth aspect of the invention provides a method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices, the method comprising generating a first carrier signal having a first frequency; modulating the first carrier signal to generate first down-link signals; transmitting the first down-link signals from the antenna to the mobile communication devices in a first beam; generating a second carrier signal having a second frequency which is different to the first frequency; modulating the second carrier signal to generate second down-link signals; and transmitting the second down-link signals from the antenna to the mobile communication devices in a second beam which is directed at a different angle to the first beam.
  • a seventh aspect of the invention provides a telecommunication antenna system for communicating with a plurality of mobile communication devices, the system comprising: a multi-beam phased array antenna comprising a plurality of antenna elements; means for generating a first carrier signal having a first frequency; a modulator for modulating the first carrier signal to generate first down-link signals; means for generating a second carrier signal having a second frequency which is different to the first frequency; a modulator for modulating the second carrier signal to generate second down-link signals; a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first modulator, and a second signal port coupled to the second modulator; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports so as to cause each antenna element to radiate the first down-link signals in a first beam, and to radiate the second down-link signals in a second beam which is angularly spaced from the first beam.
  • the sixth and seventh aspects of the invention remove the need for a combiner 1 1 2. Instead, the two signals are input into separate input ports of a multi-beam antenna.
  • the beams may be seaparate azimuthally but preferably the second beam is downtilted with respect to the first beam.
  • the antenna comprises a plurality of antenna elements mounted, when in use, at different heights.
  • the system/method employs multiplexing and/or demultiplexing so as to communicate with a plurality of mobile communication devices with each beam.
  • the system/method may employ time-division multiplexing, frequency-division multiplexing or code-division multiplexing. In a preferred example code-division multiplexing is used.
  • the antenna communicates using both beams simultaneously.
  • the method further comprises the step of assigning or deassigning a mobile communication device to or from one of the beams when the device moves into or out of a cell associated with the respective beam.
  • the antenna is one of a plurality of antennas forming a cellular network.
  • Preferred frequency ranges typically fall between approximately 820 MHz and 5 GHz.
  • the system may operate in a GSM frequency range of 870-960 MHz or a 'third generation' frequency range of 1 900-21 70 MHz.
  • Figure 1 illustrates a conventional cellular communication antenna system
  • Figure 2 illustrates a conventional "umbrella site" antenna system
  • FIG. 3 illustrates a pair of conventional antenna systems
  • Figure 4 illustrates an example of an antenna system according to the present invention
  • FIG. 5 illustrates the antenna system of Figure 4 in detail
  • FIG. 5A illustrates one of the signal paths in further detail
  • Figure 6 is a graph illustrating variation of the radiation patterns of the two beams with angular elevation
  • Figure 7 is a graph illustrating variation of the relative signal level of the two beams with distance from the antenna system along the x- axis
  • Figure 8 is a plan view of a cellular communication network incorporating a number of antenna systems of the type shown in Figures 4 and 5;
  • Figure 9 is a graphic illustrating down-link sources of interference for a CDMA system
  • Figure 1 0 is a graphic illustrating up-link sources of interference for a CDMA system
  • Figure 1 2 is a schematic diagram showing an alternative antenna system using a pair of carrier signal frequencies;
  • Figure 1 3 is a comparative example showing a pair of carrier signal frequencies and a single beam antenna.
  • an antenna array 30 is mounted to a mast 31 approximately sixty metres from the ground 32.
  • the antenna array 30 is connected to a first transceiver 33 and a second transceiver 34.
  • the transceiver 33 transmits and receives down-link/up-link communication signals to and from mobiles 35 located in an outer cell 36.
  • the transceiver 34 transmits and receives down-link/up-link communication signals from mobiles 37 located in an inner cell 38.
  • a processor 49 assigns/deassigns mobiles to/from the cells 36,38 based on the signal strength of the up-link signals received from the mobiles.
  • the processor 49 also acts as a down-link power control system for adjusting the power of down-link signals transmitted to the mobiles.
  • the antenna system is shown in more detail in Figure 5.
  • the antenna array 30 comprises a one-dimensional array (ie a single line) of eight radiating elements 39.
  • the elements 39 are oriented vertically (ie. parallel to the z-axis and the mast 31 shown in Figures 4 and 5).
  • the radiating elements 39 are patch elements although dipoles may also be used.
  • Each radiating element 39 is coupled to a respective antenna port of a beam forming network (BFN) 40.
  • the BFN 40 has a first signal port 41 coupled to the transceiver 33 and a second signal port 42 coupled to the transceiver 34.
  • adjustable downtilt is required, then eight adjustable phase shifters may be inserted between the hybrid couplers (not labelled) and the eight elements 39.
  • the adjustable phase shifters may be remotely adjustable as described in WO-A-96/14670 to vary downtilt of the beams.
  • Each transceiver comprises a respective duplexer 43, 44, transmitter 45, 46 and receiver 47,48.
  • the receivers 47,48 receive the N (outer), M (inner) up-link signals from their respective cells and output them at 62,63.
  • the signal channel for the upper beam is shown in detail in Figure 5A.
  • the N down-link signals are each encoded differently according to a CDMA encoding scheme (for example a scheme employing Walsh codes) by an encoder 80.
  • the encoded signals are summed by a summer 81 .
  • a carrier signal at frequency fi and the output of the summer 81 are input to a modulator 82 which provides a modulated output signal to amplifier 83.
  • the modulated output signal is amplified by amplifier 83 before being transmitted to the duplexer 43.
  • the duplexer 43 comprises a band-pass filter 86, which is set to pass signals in a down-link frequency band centred on fi .
  • Up-link signals are passed by a band-pass filter 87, which is set to pass signals in an up-link frequency band centred on a second frequency f 2 .
  • the up-link signals are amplified by an amplifier 88, demodulated by a demodulator 90 and passed to a signal splitter 89 which extracts the N different up-link signals based on the CDMA encoding scheme.
  • the encoder 80, signal splitter 89, modulator 82 and demodulator 90 are illustrated as part of the transceiver 33 located at the antenna site, it will be readily understood that any or all of these functions may be performed at a location remote from the antenna site.
  • the BFN 40 is configured as a pair of Butler matrices coupled by hybrid couplers which divide up-link signals on signal port 41 among the eight antenna ports, with each antenna port having a fixed phase offset with respect to the other output ports.
  • the phases are selected so that the down-link signals on signal port 41 are transmitted in an upper beam having a main lobe 50 ( Figure 4) with a footprint defining the outer cell 36.
  • up-link signals are received at the signal port 41 from a reception zone defined by the main lobe 50.
  • the BFN is configured so that the down-link signals on signal port 42 are transmitted in a lower beam having a main lobe 51 with a footprint defining the inner cell 38. Conversely, up-link signals are received at the signal port 42 from a reception zone defined by the main lobe 51 .
  • FIG. 6 shows the variation of the radiation pattern of the two beams with angular elevation ( 1 80° elevation being defined as the positive z-direction as shown in Figure 4) . It can be seen that the pattern includes an upper main peak 50' (corresponding with lobe 50) for the upper beam and a lower main peak 51 ' (corresponding with lobe 51 ) for the lower beam. It can be seen from Figure 6 that the lower lobe 51 is downtilted with respect to the upper lobe 50 by approximately 10 degrees. As a result the cell 38 is located radially inwardly of the cell 36.
  • Figure 7 is a section of the two beam footprints along the x-axis at zero height (the x-axis being shown in Figures 4,8,9 and 1 0). It can be seen from Figure 7 that the signal 53 from the lower beam is stronger than the signal 54 from the upper beam in the vicinity of the antenna array. As distance from the antenna array increases the situation reverses itself at the crossover point 55.
  • the frequency reuse factor is 1 , ie. all base stations and mobiles use the same carrier frequency, and the system capacity is interference- limited. All adjacent base stations are a source of interference for down-link signals and all mobiles in the area create interference for uplink signals.
  • the power controller allows the signal/(interference + noise) ratio (SINR) to be maximised by reducing the transmitted power from mobiles and thus cutting the interference they create for other users.
  • SINR signal/(interference + noise) ratio
  • Mobile radiated power is controlled by the base station this mobile is assigned to.
  • Mobiles are transferred from one base station to another (hand-off) on the basis of the signal received from the mobile.
  • the following estimation was done using hard hand-off between the inner and outer cells. That is, a mobile is assigned to the inner cell when the signal from the lower beam is greater (ie. to the left of the crossing point 55 in Figure 7) and assigned to the outer cell when the signal from the upper beam is greater (ie. to the right of the crossing point 55) .
  • Down-link interference for mobiles is created by signals radiated from base stations for other mobiles in the cell (see Figure 9). If two-beam antennas ( Figure 4) are used then inner and outer cells can be arranged and some mobiles are assigned by the processor 49 to the inner cell with the base station transmitting to them using the lower beam. Thus the number of interferers is reduced.
  • the down-link power control system implemented by the processor 49 monitors signal level at the mobile and works perfectly then the amplitude of the signal transmitted from the base station to any mobile is inversely proportional to propagation losses between the base station and mobile
  • Equations ( 1 )-(3) above apply to the conventional one-beam antenna system of Figure 1 .
  • two cells are used instead of one. So users are distributed between these cells.
  • the base station processor 49 estimates propagation losses for both beams using the signal received from the mobile; selects the beam with the higher signal level (hand-off subsystem); and sets the radiated power to provide a minimum satisfactory signal level to maintain quality of the link (using the power-control subsystem mentioned above), thus creating minimum interference for other mobiles.
  • the amplitude of the signal intended for the j-th mobile ( Figure 9) when radiated from the base station is:
  • interference for base stations is created by other mobiles (see Figure 10) .
  • the level of signal received at the base station from all users assigned to this base station is constant and equal to a minimum level needed to maintain the link.
  • the hand-off system implemented by the processor 49 assigns mobiles to the beam which provides a higher beam signal at the location of the mobile.
  • ⁇ ec2 if(L2(x ⁇ Ll(x hen L2(x ff(L2(x ⁇ Ll(x yhen L ⁇ ⁇ (7)
  • the signal received from the j-th mobile is Pred ;
  • the total interference for the link from the k-th mobile is:
  • FIG. 1 An alternative system is shown in Figure 1 2. The system is similar to the system shown in Figure 5, and identical reference numerals are used where appropriate. Only the transmitter circuitry is shown in Figure 1 2 for purposes of clarity. However, equivalent receiver circuitry (not shown) will typically also be included.
  • a signal generator 100 generates a sinusoidal carrier signal at frequency fi which is modulated by the modulator 82.
  • the modulator 103 associated with the transmitter 46 for the other beam is provided with a sinusoidal carrier signal from a signal generator 101 with a different frequency 2.
  • the signals transmitted in the upper and lower beams are at different frequencies. This reduces interference between the two beams.

Abstract

A method of communicating between a multi-beam phased array antenna (30) and a plurality of mobile communication devices (35, 37) located at different distances from the antenna. The antenna comprises a plurality of antenna elements (39) mounted at different heights. The method comprises communicating between the antenna and the further of the mobile communication devices using an upper beam (50); and communicating between the antenna and the closer of the mobile communication devices using a lower beam (51) which is downtilted with respect to the upper beam. A method of communicating between a multi-beam phased array antenna (30) and a plurality of mobile communication devices. The method comprises generating a first carrier signal having a first frequency f1; modulating the first carrier signal to generate first down-link signals; transmitting the first down-link signals from the antenna to the mobile communication devices in a first beam; generating a second carrier signal having a second frequency f2 which is different to the first frequency; modulating the second carrier signal to generate second down-link signals; and transmitting the second down-link signals from the antenna to the mobile communication devices in a second beam which is directed at a different angle to the first beam.

Description

TELECOMMUNICATION ANTENNA SYSTEM
The Technical Field
The present invention relates to a telecommunication antenna system; a method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices; and a phased array feed network.
Background of the Invention
A conventional cellular telecommunication antenna system is shown in Figure 1 . An antenna 1 is mounted on a mast 2 and connected to a transceiver 3. The antenna 1 has a downtuted radiation pattern 4 which covers a cell 5 on the ground 6. The transceiver 3 transmits down-link signals 7 to mobile communication devices (hereinafter referred to as "mobiles") 8 in the cell 5, and also receives up-link signals 9 from the mobiles 8. The transceiver 3 communicates with a number of mobiles in the cell 5 using a suitable multiple access method. Examples are frequency division multiple access (FDMA), code division multiple access (CDMA), time division multiple access (TDMA) and spatial division multiple access (SDMA).
When the number of mobiles in the cell 5 reaches an upper limit (depending on the amount of interference between mobiles), no further mobiles can be serviced. A conventional solution to this problem is illustrated in Figure 2. If sufficient space is available on the mast 2, a second antenna array 10 is mounted below the antenna array 1 , coupled to a respective transceiver 1 1 coupled with a power control system 1 2. The radiation pattern of the array 1 is steered as shown at 1 3 to illuminate an outer cell 14. The radiation pattern 1 5 of the second array 10 is downtuted to illuminate an inner cell (or microcell) 1 6. The power control system 1 2 reduces the signals received and transmitted by antenna array 10 in order to prevent overlap between the two cells. The site shown in Figure 2 is conventionally known as an "umbrella site".
An alternative solution is shown in Figure 3. In this case, the radiation pattern of the antenna array 1 is downtuted as indicated at 1 7 to illuminate a smaller cell 1 8, and an additional antenna array 1 9, mast 20 and transceiver 21 are installed to service a second cell 22.
By splitting the cell 5 into a number of microcells 14, 1 6 or 1 8,22, a larger density of mobiles can be serviced. However the conventional solutions suffer from various problems. In the solution of Figure 2 an additional antenna array 10 is required. Sufficient room may not be available on the antenna mast 2. Also, the cost of acquiring additional space on the mast 2 may be prohibitive. In the solution of Figure 3 additional property must be acquired to install the second antenna system 1 9-21 . The antenna system 1 9-21 is also unsightly and expensive to install.
A further conventional system is described in US-A-5,890,067. An antenna produces a number of spaced beam spots. Forward communication channels follow mobile units as they move between beam spots. The precise form of the antenna is not described.
Disclosure of the Invention
An object of the present invention is to address or at least ameliorate the problems of the prior art described above, or at least to provide the public with a useful choice. According to a first aspect of the invention there is provided a method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices located at different distances from the antenna, the antenna comprising a plurality of antenna elements mounted at different heights, the method comprising communicating between the antenna and the further of the mobile communication devices using an upper beam; and communicating between the antenna and the closer of the mobile communication devices using a lower beam which is downtilted with respect to the upper beam.
According to a second aspect of the invention there is provided a telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first transmitter for transmitting first down-link signals; a second transmitter for transmitting second down-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first transmitter, a second signal port coupled to the second transmitter; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element radiates the first down-link signals in an upper beam towards the further of the mobile communication devices, and radiates the second down-link signals in a lower beam towards the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
According to a third aspect of the invention there is provided a telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first receiver for receiving first up-link signals; a second receiver for receiving second up-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first receiver, a second signal port coupled to the second receiver, and means for providing a phase shift between up-link signals at the antenna ports and up-link signals at the first and second signal ports, signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element receives the first up-link signals in an upper beam from the further of the mobile communication devices, and receives the second up-link signals in a lower beam from the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
A fourth aspect of the invention provides a method of installing a telecommunication antenna system, the method comprising the steps of:
( 1 ) providing an antenna system according to the second or third aspect of the invention; and (2) mounting the antenna elements at different heights.
The first to fourth aspects of the present invention provide a single antenna array with a multi-beam radiation pattern with relatively downtilted beams. When provided in a cellular system of the type shown in Figure 1 , the cell can be divided into inner and outer cells, each serviced by a respective beam. This increases the number of mobiles that can be serviced in a given area.
The antenna elements may have a variety of configurations. For instance the elements may be arranged in a one-dimensional or two dimensional array. Typically the elements are substantially coplanar. At least two of the elements are arranged in use at different heights so as to provide downtilt between the two beams. In a preferred example the elements are arranged in a substantially vertical one-dimensional array.
The second and third aspects of the invention relate to a transmitting antenna system and a receiving antenna system respectively. In a preferred example the system can both transmit and receive signals.
The means for providing a phase shift typically comprises a plurality of phase shifters, which may be variable phase shifters. Typically the variable phase shifters have relatively movable components which are relatively movable to vary the phase shift. The components may be moved manually. Preferably electromechanical means are provided to move the components, and a controller is provided for supplying drive signals to the electromechanical means to adjust the beam angle of the antenna. An example of a phase shift system of this type is given in WO-A-96/1 4670.
In accordance with a fifth aspect of the present invention there is provided a phased array feed network including a plurality of antenna ports; a plurality of signal ports; and means for providing a phase shift between signals at the antenna ports and signals at the signal ports, wherein the number of signal ports is less than the number of antenna ports.
The fifth aspect of the invention provides a feed network which is specially adapted for use in a multi-beam antenna system according to the second or third aspects of the invention. In contrast to conventional feed networks where the number of antenna ports is equal to the number of signal ports, the feed network only requires a limited number of signal ports, equal to the number of beams being serviced.
Typically the number of antenna ports is a factor of 2 (ie., 4,8, 1 6 etc) . Preferably the number of signal ports is two. In a particularly preferred example the network has two signal ports and eight antenna ports.
A single-beam antenna system is shown in Figure 1 3 as a comparative example. An antenna 1 10 radiates down-link signals in a beam 1 1 1 . The antenna 1 10 has a single input port 1 1 3 for receiving down-link signals. A pair of modulators 1 14, 1 1 5 modulate carrier signals at different frequencies fi and h respectively and input the modulated signals to a combiner 1 1 2. A problem with the arrangement of Figure 1 2 is that the combiner 1 1 2 introduces a significant signal loss into the system.
A sixth aspect of the invention provides a method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices, the method comprising generating a first carrier signal having a first frequency; modulating the first carrier signal to generate first down-link signals; transmitting the first down-link signals from the antenna to the mobile communication devices in a first beam; generating a second carrier signal having a second frequency which is different to the first frequency; modulating the second carrier signal to generate second down-link signals; and transmitting the second down-link signals from the antenna to the mobile communication devices in a second beam which is directed at a different angle to the first beam.
A seventh aspect of the invention provides a telecommunication antenna system for communicating with a plurality of mobile communication devices, the system comprising: a multi-beam phased array antenna comprising a plurality of antenna elements; means for generating a first carrier signal having a first frequency; a modulator for modulating the first carrier signal to generate first down-link signals; means for generating a second carrier signal having a second frequency which is different to the first frequency; a modulator for modulating the second carrier signal to generate second down-link signals; a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first modulator, and a second signal port coupled to the second modulator; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports so as to cause each antenna element to radiate the first down-link signals in a first beam, and to radiate the second down-link signals in a second beam which is angularly spaced from the first beam.
The sixth and seventh aspects of the invention remove the need for a combiner 1 1 2. Instead, the two signals are input into separate input ports of a multi-beam antenna.
The beams may be seaparate azimuthally but preferably the second beam is downtilted with respect to the first beam. Preferably the antenna comprises a plurality of antenna elements mounted, when in use, at different heights.
The following preferred features may be employed in any of the aspects of the invention.
Preferably the system/method employs multiplexing and/or demultiplexing so as to communicate with a plurality of mobile communication devices with each beam. The system/method may employ time-division multiplexing, frequency-division multiplexing or code-division multiplexing. In a preferred example code-division multiplexing is used.
Preferably the antenna communicates using both beams simultaneously.
Typically the method further comprises the step of assigning or deassigning a mobile communication device to or from one of the beams when the device moves into or out of a cell associated with the respective beam.
Typically the antenna is one of a plurality of antennas forming a cellular network.
Preferred frequency ranges typically fall between approximately 820 MHz and 5 GHz. For instance the system may operate in a GSM frequency range of 870-960 MHz or a 'third generation' frequency range of 1 900-21 70 MHz.
Brief Description of the Drawings
An example of the present invention will now be described and contrasted with the prior art systems with reference to the accompanying drawings in which:
Figure 1 illustrates a conventional cellular communication antenna system; Figure 2 illustrates a conventional "umbrella site" antenna system;
Figure 3 illustrates a pair of conventional antenna systems;
Figure 4 illustrates an example of an antenna system according to the present invention;
Figure 5 illustrates the antenna system of Figure 4 in detail;
Figure 5A illustrates one of the signal paths in further detail;
Figure 6 is a graph illustrating variation of the radiation patterns of the two beams with angular elevation;
Figure 7 is a graph illustrating variation of the relative signal level of the two beams with distance from the antenna system along the x- axis;
Figure 8 is a plan view of a cellular communication network incorporating a number of antenna systems of the type shown in Figures 4 and 5;
Figure 9 is a graphic illustrating down-link sources of interference for a CDMA system;
Figure 1 0 is a graphic illustrating up-link sources of interference for a CDMA system;
Figure 1 1 is a graphic illustrating the total interference Ik received by a mobile for a one beam CDMA system and a two beam CDMA system along the y = 0 and y = 2km lines; Figure 1 2 is a schematic diagram showing an alternative antenna system using a pair of carrier signal frequencies; and
Figure 1 3 is a comparative example showing a pair of carrier signal frequencies and a single beam antenna.
Best Mode for carrying out the Invention
Referring to Figure 4, an antenna array 30 is mounted to a mast 31 approximately sixty metres from the ground 32. The antenna array 30 is connected to a first transceiver 33 and a second transceiver 34. The transceiver 33 transmits and receives down-link/up-link communication signals to and from mobiles 35 located in an outer cell 36. The transceiver 34 transmits and receives down-link/up-link communication signals from mobiles 37 located in an inner cell 38. A processor 49 assigns/deassigns mobiles to/from the cells 36,38 based on the signal strength of the up-link signals received from the mobiles. The processor 49 also acts as a down-link power control system for adjusting the power of down-link signals transmitted to the mobiles.
The antenna system is shown in more detail in Figure 5. The antenna array 30 comprises a one-dimensional array (ie a single line) of eight radiating elements 39. The elements 39 are oriented vertically (ie. parallel to the z-axis and the mast 31 shown in Figures 4 and 5). Typically the radiating elements 39 are patch elements although dipoles may also be used. Each radiating element 39 is coupled to a respective antenna port of a beam forming network (BFN) 40. The BFN 40 has a first signal port 41 coupled to the transceiver 33 and a second signal port 42 coupled to the transceiver 34. If adjustable downtilt is required, then eight adjustable phase shifters may be inserted between the hybrid couplers (not labelled) and the eight elements 39. The adjustable phase shifters may be remotely adjustable as described in WO-A-96/14670 to vary downtilt of the beams.
Each transceiver comprises a respective duplexer 43, 44, transmitter 45, 46 and receiver 47,48. The transmitter 45 receives N down-link signals 60 (where N = number of mobiles currently assigned to outer cell 36). Similarly the transmitter 46 receives M down-link signals 61 (where M = number of mobiles currently assigned to inner cell 38). The receivers 47,48 receive the N (outer), M (inner) up-link signals from their respective cells and output them at 62,63.
The signal channel for the upper beam is shown in detail in Figure 5A. The N down-link signals are each encoded differently according to a CDMA encoding scheme (for example a scheme employing Walsh codes) by an encoder 80. The encoded signals are summed by a summer 81 . A carrier signal at frequency fi and the output of the summer 81 are input to a modulator 82 which provides a modulated output signal to amplifier 83. The modulated output signal is amplified by amplifier 83 before being transmitted to the duplexer 43. The duplexer 43 comprises a band-pass filter 86, which is set to pass signals in a down-link frequency band centred on fi . Up-link signals are passed by a band-pass filter 87, which is set to pass signals in an up-link frequency band centred on a second frequency f2. The up-link signals are amplified by an amplifier 88, demodulated by a demodulator 90 and passed to a signal splitter 89 which extracts the N different up-link signals based on the CDMA encoding scheme.
Although the encoder 80, signal splitter 89, modulator 82 and demodulator 90 are illustrated as part of the transceiver 33 located at the antenna site, it will be readily understood that any or all of these functions may be performed at a location remote from the antenna site.
The BFN 40 is configured as a pair of Butler matrices coupled by hybrid couplers which divide up-link signals on signal port 41 among the eight antenna ports, with each antenna port having a fixed phase offset with respect to the other output ports. The phases are selected so that the down-link signals on signal port 41 are transmitted in an upper beam having a main lobe 50 (Figure 4) with a footprint defining the outer cell 36. Conversely, up-link signals are received at the signal port 41 from a reception zone defined by the main lobe 50.
Similarly, the BFN is configured so that the down-link signals on signal port 42 are transmitted in a lower beam having a main lobe 51 with a footprint defining the inner cell 38. Conversely, up-link signals are received at the signal port 42 from a reception zone defined by the main lobe 51 .
The radiation pattern of the antenna array is shown in detail in Figure 6. Figure 6 shows the variation of the radiation pattern of the two beams with angular elevation ( 1 80° elevation being defined as the positive z-direction as shown in Figure 4) . It can be seen that the pattern includes an upper main peak 50' (corresponding with lobe 50) for the upper beam and a lower main peak 51 ' (corresponding with lobe 51 ) for the lower beam. It can be seen from Figure 6 that the lower lobe 51 is downtilted with respect to the upper lobe 50 by approximately 10 degrees. As a result the cell 38 is located radially inwardly of the cell 36.
Figure 7 is a section of the two beam footprints along the x-axis at zero height (the x-axis being shown in Figures 4,8,9 and 1 0). It can be seen from Figure 7 that the signal 53 from the lower beam is stronger than the signal 54 from the upper beam in the vicinity of the antenna array. As distance from the antenna array increases the situation reverses itself at the crossover point 55. Let us consider how network capacity will be affected in a CDMA system if the two-beam antenna of Figure 4 is used in the hexagonal cellular network shown in Figure 10. Antennas are located at base stations 70,71 ,72,73 etc and service inner cells 74 etc (indicated with dark shading) and outer cells 75 etc. In a perfect CDMA system the frequency reuse factor is 1 , ie. all base stations and mobiles use the same carrier frequency, and the system capacity is interference- limited. All adjacent base stations are a source of interference for down-link signals and all mobiles in the area create interference for uplink signals.
The power controller allows the signal/(interference + noise) ratio (SINR) to be maximised by reducing the transmitted power from mobiles and thus cutting the interference they create for other users. Mobile radiated power is controlled by the base station this mobile is assigned to.
Mobiles are transferred from one base station to another (hand-off) on the basis of the signal received from the mobile. The following estimation was done using hard hand-off between the inner and outer cells. That is, a mobile is assigned to the inner cell when the signal from the lower beam is greater (ie. to the left of the crossing point 55 in Figure 7) and assigned to the outer cell when the signal from the upper beam is greater (ie. to the right of the crossing point 55) . Let us estimate the single cell case first. The configuration of the system considered is shown in Figure 8.
Down-link SINR improvement (single cell)
Down-link interference for mobiles is created by signals radiated from base stations for other mobiles in the cell (see Figure 9). If two-beam antennas (Figure 4) are used then inner and outer cells can be arranged and some mobiles are assigned by the processor 49 to the inner cell with the base station transmitting to them using the lower beam. Thus the number of interferers is reduced.
If the down-link power control system implemented by the processor 49 monitors signal level at the mobile and works perfectly then the amplitude of the signal transmitted from the base station to any mobile is inversely proportional to propagation losses between the base station and mobile
TO/i l lx), ( 1 )
where P0 - constant (equals power received by mobile), L1 (x) - propagation loss from base station to mobile located at distance x from base station.
After propagation to the mobile the transmitted level is reduced by propagation loss, so every mobile receives constant power
[P0/L Mx)) -L 1 (x) = P0 (2)
independent of its location in the cell. Signals to all other mobiles are really interferences for this mobile so the total interference received by the k-th mobile is
Figure imgf000016_0001
Equations ( 1 )-(3) above apply to the conventional one-beam antenna system of Figure 1 . For the two-beam antenna of Figure 4, two cells are used instead of one. So users are distributed between these cells. For hand-off between inner and outer cells we assume the following logic: when establishing a link with a mobile, the base station processor 49 estimates propagation losses for both beams using the signal received from the mobile; selects the beam with the higher signal level (hand-off subsystem); and sets the radiated power to provide a minimum satisfactory signal level to maintain quality of the link (using the power-control subsystem mentioned above), thus creating minimum interference for other mobiles. Then the amplitude of the signal intended for the j-th mobile (Figure 9) when radiated from the base station is:
P0 P0
Pτadl = if(L2(x/ ) ≥ Ll(x }))then ;if(Ll(xl ) > L2(x , ))then 2(X / ) " ' " Ll(xt )
(4)
The same signal when received by the k-th mobile (Figure 9) then is:
P0 P
Prec; k = if(L2x/) ≥ π(X/)yhen L2(xk);if(Ll(x ,) > L2(xl)yhen-rr^Ll(xk ) (5)
Wx.) L\(x,)
The total interference received by the k-th mobile (Figure 9) then is:
A = ∑Pre (6)
/=! ,≠k
Using expressions (3) and (6) we can estimate the interference level for a one-beam and a two-beam antenna as the mobile moves away from the base station along the x-axis. Results are shown in Figure 1 1 . Moving in the x-direction along the y = 0 contour, the interference signal level for the conventional one-beam system of Figure 1 is indicated at 90. For the two-beam system of Figure 4, the interference signal level is indicated at 91 . It can be seen that the interference signal level 91 for the two-beam system is significantly lower along the y = 0 contour. Moving in the x-direction along the y = 2km contour, the interference signal level for the conventional one- beam system is indicated at 92. For the two-beam system, the interference signal level is indicated at 93. It can be seen that the interference signal level 93 for the two-beam system is also significantly lower along the y = 2km contour
Up-link SINR improvement (single cell)
For up-link signals, interference for base stations is created by other mobiles (see Figure 10) .
If the power control sub-system works perfectly then the level of signal received at the base station from all users assigned to this base station is constant and equal to a minimum level needed to maintain the link. The hand-off system implemented by the processor 49 assigns mobiles to the beam which provides a higher beam signal at the location of the mobile.
For a two beam cell, some users are assigned to the inner cell, which is covered with a higher level than the conventional one-beam system (see Figure 7), so their transmitted power can be reduced, thus decreasing the interference level. If SINR is to be kept constant then the number of users can be increased so improving the system capacity. Let us estimate what gain in capacity can be obtained.
It is necessary to estimate the changes in interference levels for two beams. For the channel associated with the lower beam (footprint L2) the signal received from the j-th mobile is
Ϋτec2 =if(L2(x ≥Ll(x hen L2(x ff(L2(x <Ll(x yhen L χ Λ (7)
' ' ' Z2(x.) ' ' ' Ll(Xj) '
For the channel associated with the upper beam (footprint L1 ) the signal received from the j-th mobile is Pred; (8)
Figure imgf000019_0001
The total interference for the link from the k-th mobile is:
H i ∑ Preci s /2A = ∑Prec2 , (9)
/=1 l≠k
We can estimate improvements in interference levels in the same situation as for the down-link signals using expression (9) with the following results: for the lower beam, channel interference is reduced by 3.6 dB; for the upper beam channel the interference level is reduced by 0.7 dB. The reduction in interference for the inner cell is significant. All estimations were done for uniform distribution of mobiles in the cell in a square grid separated by 40 m (indicated at 76 in Figure 8) . The improvement will be greater if mobiles are concentrated close to the antenna location.
An alternative system is shown in Figure 1 2. The system is similar to the system shown in Figure 5, and identical reference numerals are used where appropriate. Only the transmitter circuitry is shown in Figure 1 2 for purposes of clarity. However, equivalent receiver circuitry (not shown) will typically also be included.
A signal generator 100 generates a sinusoidal carrier signal at frequency fi which is modulated by the modulator 82. The modulator 103 associated with the transmitter 46 for the other beam is provided with a sinusoidal carrier signal from a signal generator 101 with a different frequency 2. As a result the signals transmitted in the upper and lower beams are at different frequencies. This reduces interference between the two beams.
Where in the foregoing description reference has been made to integers or components having known equivalents then such equivalents are herein incorporated as if individually set forth.
Although this invention has been described by way of example it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims

1 . A method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices located at different distances from the antenna, the antenna comprising a plurality of antenna elements mounted at different heights, the method comprising communicating between the antenna and the further of the mobile communication devices using an upper beam; and communicating between the antenna and the closer of the mobile communication devices using a lower beam which is downtilted with respect to the upper beam.
2. A method according to claim 1 , the method further comprising multiplexing a plurality of first down-link signals; transmitting the multiplexed first down-link signals in the upper beam; multiplexing a plurality of second down-link signals; and transmitting the multiplexed second down-link signals in the lower beam.
3. A method according to claim 2 wherein the first and second down-link signals are multiplexed by encoding the down-link signals according to a code-division multiplexing scheme.
4. A method according to any one of the preceding claims, the method further comprising demultiplexing a plurality of first up-link signals received in the upper beam; and demultiplexing a plurality of second up-link signals received in the lower beam.
5. A method according to claim 4 wherein the first and second down-link signals are demultiplexed by decoding the down-link signals according to a code-division demultiplexing scheme.
6. A method according to any one of the preceding claims, comprising communicating using the upper and lower beams simultaneously.
7. A method according to any one of the preceding claims, the method further comprising the step of assigning or deassigning a mobile communication device to or from one of the beams when the device moves into or out of a cell associated with the respective beam.
8. A method according to any one of the preceding claims, wherein the antenna is one of a plurality of antennas forming a cellular network.
9. A method according to any one of the preceding claims wherein the antenna elements are mounted in a substantially vertical orientation.
10. A method according to any one of the preceding claims wherein the antenna elements are configured as a one-dimensional array.
1 1 . A telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first transmitter for transmitting first down-link signals; a second transmitter for transmitting second down-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first transmitter, a second signal port coupled to the second transmitter; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element radiates the first down-link signals in an upper beam towards the further of the mobile communication devices, and radiates the second down-link signals in a lower beam towards the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
1 2. A system according to claim 1 1 further comprising means for mounting the antenna elements at different heights.
1 3. A system according to claim 1 1 or 1 2 further comprising a first multiplexer for multiplexing a plurality of first down-link signals and passing the multiplexed first down-link signals to the first transmitter; and a second multiplexer for multiplexing a plurality of second down- link signals and passing the multiplexed second down-link signals to the second transmitter.
14. A system according to claim 1 3 wherein the first and second multiplexers comprise encoders for encoding the down-link signals according to a code-division multiplexing scheme.
1 5. A telecommunication antenna system for communicating with a plurality of mobile communication devices located at different distances from the system, the system comprising: a plurality of antenna elements; a first receiver for receiving first up-link signals; a second receiver for receiving second up-link signals; and a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first receiver, a second signal port coupled to the second receiver, and means for providing a phase shift between up-link signals at the antenna ports and up-link signals at the first and second signal ports, signal ports, the antenna elements and feed network being configured such that when the antenna elements are mounted, in use, at different heights, each element receives the first up-link signals in an upper beam from the further of the mobile communication devices, and receives the second up-link signals in a lower beam from the closer of the mobile communication devices, the lower beam being downtilted with respect to the upper beam.
1 6. A telecommunication antenna system according to claim 1 5 further comprising means for mounting the antenna elements at different heights.
1 7. A system according to claim 1 2 or 1 6 wherein the means for mounting the antenna elements at different heights comprises an elongate mast and the antenna elements are aligned with the mast.
1 8. A system according to any one of claims 1 5 to 1 7, the system further comprising a first demultiplexer for demultiplexing a plurality of first up-link signals received in the upper beam; and a second demultiplexer for demultiplexing a plurality of second up-link signals received in the lower beam.
1 9. A system according to claim 1 8 wherein the first and second demultiplexers are decoders for decoding the down-link signals according to a code-division demultiplexing scheme.
20. A system according to any one of claims 1 1 to 1 9, wherein the antenna is adapted to communicate using the upper and lower beams simultaneously.
21 . A system according to any one of claims 1 1 to 20, further comprising a processor for assigning or deassigning a mobile communication device to or from one of the beams when the device moves into or out of a cell associated with the respective beam.
22. A system according to any one of claims 1 1 to 21 wherein the antenna elements are configured as a one-dimensional array.
23. A system according to any one of claims 1 1 to 22 wherein the antenna elements are mounted, when in use, in a substantially vertically orientation.
24. A cellular network comprising a plurality of systems according to any one of claims 1 1 to 23.
25. A method of installing a telecommunication antenna system, the method comprising the steps of:
( 1 ) providing an antenna system according to any one of claims 1 1 to 23 or a cellular network according to claim 24; and
(2) mounting the antenna elements at different heights.
26. A method of communicating between a multi-beam phased array antenna and a plurality of mobile communication devices, the method comprising generating a first carrier signal having a first frequency; modulating the first carrier signal to generate first down-link signals; transmitting the first down-link signals from the antenna to the mobile communication devices in a first beam; generating a second carrier signal having a second frequency which is different to the first frequency; modulating the second carrier signal to generate second down-link signals; and transmitting the second down-link signals from the antenna to the mobile communication devices in a second beam which is directed at a different angle to the first beam.
27. A method according to claim 26, the method further comprising multiplexing a plurality of first down-link signals; transmitting the multiplexed first down-link signals in the first beam; multiplexing a plurality of second down-link signals; and transmitting the multiplexed second down-link signals in the second beam.
28. A method according to claim 27 wherein the first and second down-link signals are multiplexed by encoding the down-link signals according to a code-division multiplexing scheme.
29. A method according to any one of claims 26 to 28, wherein the antenna transmits using the first and second beams simultaneously.
30. A method according to any one of claims 26 to 29, the method further comprising the step of assigning or deassigning a mobile communication device to or from one of the beams when the device moves into or out of a cell associated with the respective beam.
31 . A method according to any one of claims 26 to 30, wherein the antenna is one of a plurality of antennas forming a cellular network.
32. A method according to any one of claims 26 to 31 , wherein the second beam is downtilted with respect to the first beam.
33. A method according to any one of claims 26 to 32 wherein the antenna comprises a plurality of antenna elements mounted at different heights.
34. A telecommunication antenna system for communicating with a plurality of mobile communication devices, the system comprising: a multi-beam phased array antenna comprising a plurality of antenna elements; means for generating a first carrier signal having a first frequency; a modulator for modulating the first carrier signal to generate first down-link signals; means for generating a second carrier signal having a second frequency which is different to the first frequency; a modulator for modulating the second carrier signal to generate second down-link signals; a phased array feed network including a plurality of antenna ports each coupled to a respective antenna element, a first signal port coupled to the first modulator, and a second signal port coupled to the second modulator; and means for providing a phase shift between down-link signals at the antenna ports and down-link signals at the first and second signal ports so as to cause each antenna element to radiate the first down-link signals in a first beam, and to radiate the second down-link signals in a second beam which is angularly spaced from the first beam.
35. A system according to claim 34 further comprising a first multiplexer for multiplexing a plurality of first down-link signals and passing the multiplexed first down-link signals to the first modulator; and a second multiplexer for multiplexing a plurality of second downlink signals and passing the multiplexed second down-link signals to the second modulator.
36. A system according to claim 35 wherein the first and second multiplexers comprise encoders for encoding the down-link signals according to a code-division multiplexing scheme.
37. A system according to any one of claims 34 to 36 wherein the antenna comprises a plurality of antenna elements mounted at different heights configured as a one-dimensional array.
38. A system according to any one of claims 1 1 to 23 or 34 to 37 wherein the antenna is suitable for use in a cellular network.
39. A phased array feed network including: a plurality of antenna ports; a plurality of signal ports; and means for providing a phase shift between signals at the antenna ports and signals at the signal ports, wherein the number of signal ports is less than the number of antenna ports.
40. A network according to claim 39 comprising a first Butler matrix coupled to a first signal port, a second Butler matrix coupled to a second signal port, and a plurality of couplers coupling the outputs of the first and second Butler matrices.
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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003041218A1 (en) * 2001-11-09 2003-05-15 Ems Technologies, Inc. Beamformer for multi-beam broadcast antenna
WO2003043127A2 (en) * 2001-11-14 2003-05-22 Qinetiq Limited Antenna system
WO2003043125A1 (en) * 2001-11-09 2003-05-22 Ems Technologies, Inc. Beamformer for multi-beam receive antenna
WO2003052866A1 (en) * 2001-12-14 2003-06-26 Nokia Corporation Method of controlling transmission in a radio system
WO2004014095A1 (en) * 2002-07-31 2004-02-12 Yuan Xie A three-dimension coverage cellular network
WO2004015812A1 (en) * 2002-08-07 2004-02-19 Intel Corporation Antenna system for improving the performance of a short range wireless network
WO2004036785A2 (en) * 2002-10-19 2004-04-29 Quintel Technology Limited Mobile radio base station
WO2004088790A1 (en) * 2003-04-02 2004-10-14 Quintel Technology Limited Phased array antenna system with variable electrical tilt
WO2004102739A1 (en) * 2003-05-17 2004-11-25 Quintel Technology Limited Phased array antenna system with adjustable electrical tilt
US6864837B2 (en) 2003-07-18 2005-03-08 Ems Technologies, Inc. Vertical electrical downtilt antenna
WO2006071152A1 (en) * 2004-12-30 2006-07-06 Telefonaktiebolaget Lm Ericsson (Publ) An improved antenna for a radio base station in a mobile cellular telephony network
WO2007091024A2 (en) * 2006-02-09 2007-08-16 Quintel Technology Limited Phased array antenna system with multiple beams
WO2010048062A1 (en) * 2008-10-23 2010-04-29 T-Mobile Usa, Inc. Flat panel antenna, such as for cellular telephone communications
KR101111467B1 (en) 2003-11-07 2012-02-21 큐인텔 테크놀로지 리미티드 Phased array antenna system with controllable electrical tilt
US20120264469A1 (en) * 2009-06-15 2012-10-18 Luc Dartois Base transceiver station and associated method for communication between base transceiver station and user equipments
WO2013090456A1 (en) * 2011-12-12 2013-06-20 Qualcomm Incorporated Reconfigurable millimeter wave multibeam antenna array
WO2015036034A1 (en) * 2013-09-13 2015-03-19 Nokia Solutions And Networks Oy Vertical tilting
EP2860822A4 (en) * 2012-06-11 2015-06-17 Huawei Tech Co Ltd Base station antenna and base station antenna feed network
EP2975688B1 (en) * 2014-07-15 2019-10-09 Alcatel Lucent Antenna feed and method of configuring an antenna feed

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4638317A (en) * 1984-06-19 1987-01-20 Westinghouse Electric Corp. Orthogonal beam forming network
US5551060A (en) * 1991-09-03 1996-08-27 Nippon Telegraph And Telephone Corporation Structure of cells within a mobile communication system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4638317A (en) * 1984-06-19 1987-01-20 Westinghouse Electric Corp. Orthogonal beam forming network
US5551060A (en) * 1991-09-03 1996-08-27 Nippon Telegraph And Telephone Corporation Structure of cells within a mobile communication system

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003043125A1 (en) * 2001-11-09 2003-05-22 Ems Technologies, Inc. Beamformer for multi-beam receive antenna
WO2003041218A1 (en) * 2001-11-09 2003-05-15 Ems Technologies, Inc. Beamformer for multi-beam broadcast antenna
CN100468863C (en) * 2001-11-14 2009-03-11 昆特尔科技有限公司 Antenna system
WO2003043127A2 (en) * 2001-11-14 2003-05-22 Qinetiq Limited Antenna system
WO2003043127A3 (en) * 2001-11-14 2003-08-14 Qinetiq Ltd Antenna system
US7230570B2 (en) 2001-11-14 2007-06-12 Quintel Technology Limited Antenna system
AU2002337354B2 (en) * 2001-11-14 2006-06-22 Quintel Technology Limited Antenna system
WO2003052866A1 (en) * 2001-12-14 2003-06-26 Nokia Corporation Method of controlling transmission in a radio system
CN101321006A (en) * 2001-12-14 2008-12-10 诺基亚公司 Method of controlling transmission in a radio system
WO2004014095A1 (en) * 2002-07-31 2004-02-12 Yuan Xie A three-dimension coverage cellular network
CN100350813C (en) * 2002-07-31 2007-11-21 谢元 A three-dimension coverage cellular network
US7034749B2 (en) 2002-08-07 2006-04-25 Intel Corporation Antenna system for improving the performance of a short range wireless network
CN1615562B (en) * 2002-08-07 2010-06-09 英特尔公司 Antenna system for improving the performance of a short range wireless network
US7486235B2 (en) 2002-08-07 2009-02-03 Intel Corporation Antenna system for improving the performance of a short range wireless network
WO2004015812A1 (en) * 2002-08-07 2004-02-19 Intel Corporation Antenna system for improving the performance of a short range wireless network
WO2004036785A3 (en) * 2002-10-19 2004-06-24 Quintel Technology Ltd Mobile radio base station
WO2004036785A2 (en) * 2002-10-19 2004-04-29 Quintel Technology Limited Mobile radio base station
US7433713B2 (en) 2002-10-19 2008-10-07 Quintel Technology Limited Mobile radio base station
KR101130142B1 (en) 2003-04-02 2012-03-28 큐인텔 테크놀로지 리미티드 Phased array antenna with variable electrical tilt
US7868823B2 (en) 2003-04-02 2011-01-11 Quintel Technology Limited Phased array antenna system with variable electrical tilt
US7400296B2 (en) 2003-04-02 2008-07-15 Quintel Technology Limited Phased array antenna system with variable electrical tilt
AU2004226625B2 (en) * 2003-04-02 2007-09-20 Quintel Technology Limited Phased array antenna system with variable electrical tilt
US8174442B2 (en) 2003-04-02 2012-05-08 Quintel Technology Limited Phased array antenna system with variable electrical tilt
WO2004088790A1 (en) * 2003-04-02 2004-10-14 Quintel Technology Limited Phased array antenna system with variable electrical tilt
US7450066B2 (en) 2003-05-17 2008-11-11 Quintel Technology Limtied Phased array antenna system with adjustable electrical tilt
WO2004102739A1 (en) * 2003-05-17 2004-11-25 Quintel Technology Limited Phased array antenna system with adjustable electrical tilt
US6864837B2 (en) 2003-07-18 2005-03-08 Ems Technologies, Inc. Vertical electrical downtilt antenna
KR101111467B1 (en) 2003-11-07 2012-02-21 큐인텔 테크놀로지 리미티드 Phased array antenna system with controllable electrical tilt
WO2006071152A1 (en) * 2004-12-30 2006-07-06 Telefonaktiebolaget Lm Ericsson (Publ) An improved antenna for a radio base station in a mobile cellular telephony network
WO2007091024A3 (en) * 2006-02-09 2007-11-01 Quintel Technology Ltd Phased array antenna system with multiple beams
WO2007091024A2 (en) * 2006-02-09 2007-08-16 Quintel Technology Limited Phased array antenna system with multiple beams
US9118361B2 (en) 2006-02-09 2015-08-25 Quintel Technology Limited Phased array antenna system with multiple beam
WO2010048062A1 (en) * 2008-10-23 2010-04-29 T-Mobile Usa, Inc. Flat panel antenna, such as for cellular telephone communications
US20120264469A1 (en) * 2009-06-15 2012-10-18 Luc Dartois Base transceiver station and associated method for communication between base transceiver station and user equipments
US9083398B2 (en) * 2009-06-15 2015-07-14 Alcatel Lucent Base transceiver station and associated method for communication between base transceiver station and user equipments
WO2013090456A1 (en) * 2011-12-12 2013-06-20 Qualcomm Incorporated Reconfigurable millimeter wave multibeam antenna array
US8912957B2 (en) 2011-12-12 2014-12-16 Qualcomm Incorporated Reconfigurable millimeter wave multibeam antenna array
EP2860822A4 (en) * 2012-06-11 2015-06-17 Huawei Tech Co Ltd Base station antenna and base station antenna feed network
WO2015036034A1 (en) * 2013-09-13 2015-03-19 Nokia Solutions And Networks Oy Vertical tilting
EP2975688B1 (en) * 2014-07-15 2019-10-09 Alcatel Lucent Antenna feed and method of configuring an antenna feed

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