United States Patent 1.
`Searle et al.
`
`[54] BASE STATION ANTENNA ARRANGEMENT
`
`[75]
`
`Inventors: Jeffrey G. Searle, Galmpton, Nr
`Brixham; Stuart J. Dean, Paignton;
`Peter J. Chrystie, Brixham; Keith R.
`Broome, Torquay; Christopher R.
`Cox, Salcombe; Stephen J. Westlake,
`Brixham,all of United Kingdom
`
`[73] Assignee: Northern Telecom Limited, Montreal,
`Canada
`
`{21] Appl. No.: 289,920
`
`[22]
`
`Filed:
`
`Aug. 12, 1994
`
`[30]
`
`Foreign Application Priority Data
`
`United Kingdom ..
`
`[GB]
`Aug. 12, 1993
`United Kingdom 0...cesses 9316816
`United Kingdom ..
`i
`[GB]
`Aug. 12, 1993
`United Kingdom ..
`[GB]
`Aug. 12, 1993
`United Kingdom ..
`[GB]
`Aug. 12, 1993
`United Kingdom ..
`[GB]
`Ang. 12, 1993
`United Kingdom ..
`[GB]
`Aug. 12, 1993
`[GB]
`Aug. 12, 1993
`United Kingdom ................ 9316832
`[GB]
`Aug. 12, 1993
`[51]
`Uitte C1 icececsccscccecsecssssseasesacssevessenesneesses HO01Q 3/02
`[82] U.S. Clas csc cose.cesses carvers 342/374; 342/373; 342/372
`[58] Field of Search oo...esessecscseseeess 342/374, 372,
`342/373
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`SQ YAAA
`
`US005596329A
`
`(11] Patent Number:
`
`5,596,329
`Jan. 21, 1997
`{451 Date of Patent:
`
`.......sssscccssenereseees 343/374
`4,489,325 12/1984 Bauck et all.
`4,626,858 12/1986 Copeland......
`-- 342/374
`
`5,166,690
`11/1992 Carlson et al.
`« 342/157
`5,434,575
`1/1994 Jelinek et al...eseeseseeeeseees 342/365
`
`FOREIGN PATENT DOCUMENTS
`
`92 309520 10/1992 European Pat. Off..
`
`Primary Examiner—Thomas H.Tareza
`Assistant Examiner—Dao L. Phan
`Attorney, Agent, or Firm—Lee, Mann, Smith, McWilliams,
`Sweeney & Ohlson
`
`[57]
`
`ABSTRACT
`
`A smart antenna for a base station comprises a plurality of
`antenna arrays each capable of forming a multiplicity of
`separate overlapping narrow beams in azimuth, the arrays
`being positioned such that the totality of beams formed by
`the arrays provides a substantially omni-directional cover-
`age in azimuth A plurality of rf. transceivers is provided
`each for transmitting and receiving rf. signals for one or
`more calls, with switching matrix means for connecting each
`transceiver with one or other of the arrays via beamformers.
`Each transceiver is connected by a switch matrix to a
`particular array to exchangerf. signals with a remote station
`located in the area covered by oneof the narrow overlapping
`beams. Means are provided for selecting for a given call
`more than one of the best received signals from the multi-
`plicity of narrow overlapping beamsandtheselected signals
`are combined to form a single receive signal input for the r-f.
`transceiver for the given call.
`
`3,979,754
`
`9/1976 ATCher
`
`..... eeeseeesceseneseesstseenees 343/754
`
`2 Claims, 17 Drawing Sheets
`
`
`
`
`46
`
`ONE PER
`FACET
`
`TOPOFMAST
`ORBUILDING
`
`|
`
`=!
`
`onereR !!
`BEAM
`
`iI1|i|\
`
`48
`
`!I| |
`
`I
`
`
`50
`
`LOW NOISE
`AMPLIFIER
`COMBINER
`||
`
`
`' SINGLE CARRIER
`|, TX POWER
`|| AMPLIFIERS
`
`} CELL
`| SHAPING
`{ATTENUATOR
`|
`
`1
`AMPLIFIER
`|
`SELECT
`
`\
`SWITCH
`\
`MATRIX
`
`Ao: mm ee ey
`
`
`
`
`
`
`FEEDER CABLES
`TO OTHER FACETS
`
`TO CABIN ELECTRONICS
`FROM CABIN ELECTRONICS
`
`
`
`Ford Motor Co.
`Exhibit 1027
`Page 001
`
`Ford Motor Co.
`Exhibit 1027
`Page 001
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 1 of 17
`
`5,596,329
`
`NARROW
`
`BEAM
`
`-—a
`
`o'
`
`
`WANTED
`
`MOBILE
`
`BASE STATIONee |
`
`aa
`
`oO
`v
`
`a
`
`|m
`
`rs
`
`Fig. 1(a
`
`|
`
`ri
`
`AZIMUTH
`
`BASE STATION
`
`
`Te MOBILE
`
`WANTED MOBILE
`
`
`
`ELEVATION
`
`Fig. 1(b
`
`Ford Motor Co.
`Exhibit 1027
`Page 002
`
`Ford Motor Co.
`Exhibit 1027
`Page 002
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 2 of 17
`
`5,596,329
`
`Fig. 2 (a)
`
`OMNI-DIRECTIONAL CONFIGURATION
`(N = 7 RE-USE FACTOR)
`
`ist TIER
`RE-USE CELLS
`
`Fig. 2 (b)
`
`TYPICAL TRI-SECTORED CONFIGURATION
`(N = 7 RE-USE FACTOR)
`
`ist TIER
`RE-USE CELL
`NON-INTERFERING
`
`
`
`
`
`
`
`Fig. 2(c
`
`TYPICAL HEX-SECTORED CONFIGURATION
`(N = 7 RE-USE FACTOR)
`
`Ford Motor Co.
`Exhibit 1027
`Page 003
`
`Ford Motor Co.
`Exhibit 1027
`Page 003
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 3 of 17
`
`5,596,329
`
`PSTN/
`ISDN
`
`
`
`Fig.3MSC OMC
`
`BSS
`
`Signalling Routes
`
`Traffic and
`
`BSS
`
`Ford Motor Co.
`Exhibit 1027
`Page 004
`
`Ford Motor Co.
`Exhibit 1027
`Page 004
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 4 of 17
`
`5,596,329
`
`I BASE!/N/// ANTENNA1
`potas |
`
`STATION
`
`
`
`| CELLULAR RADIO
`| NETWORK
`~~PASSIVE
`
`jL——J}, — _, ANTENNAS
`|
`
`Fig. 4 (a)
`
`CELLULAR |
`RADIO
`
`pase 1 TT |
`STATION ,
`'SMARTN/7 ANTENNA1
`
`NETWORK
`
`INTERFACE
`
`ANTENNA
`|
`.
`
`ARRAY Fig.512
`
`
`
`ee, 7
`
`
`ANTENNA
`ELECTRONIC
`
`
`
`| FEEDER
`, CABLES
`
`4
`
`MICROWAVE LINK
`OR LAND LINE
`
`
`
`
`
`
`
`
`BASE
`
`BASE
`
`STATION
`
`
`
`STATION
`CONTROLLER
`
`46 CONTROL
`17 18
`20
`LINK
`
`Ford Motor Co.
`Exhibit 1027
`Page 005
`
`Ford Motor Co.
`Exhibit 1027
`Page 005
`
`

`

`USS. Patent
`
`Jan. 21, 1997
`
`Sheet 5 of 17
`
`5,596,329
`
`ONE PER
`FACET
`
`|
`
`Y yo ANTENNA ARRAY
`40
`it|| TOP OF MAST
`44
`OR BUILDING
`
`| |
`
`BEAM
`
`| |
`
`48
`
`TX/RX DIPLEXER
`
`| | | |
`
`AMPLIFIER
`
`COMBINER;| LOW NOISE
`
`
`
`
`| SINGLE CARRIER
`|, TX POWER
`/\
`| AMPLIFIERS
`CELL
`
`
`
`
`
`
`P= =
`
`62
`
`5a|
`
`54
`----
`
`ATTENUATOR
`
`AMPLIFIER
`SELECT
`SWITCH
`MATRIX
`
`|
`|
`
`|l
`
`
`
`FEEDER CABLES
`
`TO OTHER FACETS
`
`
`FROM CABIN ELECTRONICS
`TO CABIN ELECTRONICS
`
`
`
`Fig.6(a)
`
`Ford Motor Co.
`Exhibit 1027
`Page 006
`
`Ford Motor Co.
`Exhibit 1027
`Page 006
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 6 of 17
`
`5,596,329
`
`TO MASTHEAD ELECTRONICS
`
`66
`
` oo
`PHASE HOPPING MODULE
`
`
`FROM MASTHEAD
`ELECTRONICS
`
`
`
`TR1 TR2|TR3 TRn SWITCH
`
`
`
`
`
`84
`MATRICES
`TRANSCEIVERS
`
`ee
`ACQUISITION
`
`iteTRACKAND "es
`SWITCH MATRIX
`TRANSMIT
`
`
`
` 82
`
`86
`CABIN
`
`ELECTRONICS
`TRANSCEIVER
`
`CONTROL
`BUS
`
`88
`
`Fig. 6 (b)
`
`Ford Motor Co.
`Exhibit 1027
`Page 007
`
`Ford Motor Co.
`Exhibit 1027
`Page 007
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 7 of 17
`
`5,596,329
`
`bl
`
`b2
`
`bn
`
`e
`
`BEAM INPUTS
`
`e
`e
`e
`e
`
`
`
`RECEIVER
`
`
`OUTPUTS
`
`FIG 7
`
`CONTROL
`ACQUISITION
`
`Ford Motor Co.
`Exhibit 1027
`Page 008
`
`Ford Motor Co.
`Exhibit 1027
`Page 008
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 8 of 17
`
`5,596,329
`
`
`K
`
`
`
`tS
`BIOS
`poseeemeeparr
`
`. B18
`
`
`Fig. 10
`
`EXISTING COMMUNICATION LINK
`
`Ford Motor Co.
`Exhibit 1027
`Page 009
`
`Ford Motor Co.
`Exhibit 1027
`Page 009
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 9 of 17
`
`5,596,329
`
` RADIATION PATTERN
`
`RADIATION PATTERN
`WITHOUT PHASE HOPPING
`
`WITH PHASE HOPPING
`
`Ford Motor Co.
`Exhibit 1027
`Page 010
`
`Ford Motor Co.
`Exhibit 1027
`Page 010
`
`

`

`PHASE
`
`RELATIVE
`
`INPUT
`
`INPUT
`
`Fig. 12 (a)
`
`Fig.12 (b)
`
`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 10 of 17
`
`5,596,329
`
`ARRAY OF FOUR
`ANTENNA
`
`ARRAY OF FOUR
`
`Ao =0 ~ 360°
`% | (A)
`
`PHASE Ao =0—360°
`FACETS
` RELATIVE
`
`
`Ford Motor Co.
`Exhibit 1027
`Page 011
`
`Ford Motor Co.
`Exhibit 1027
`Page 011
`
`

`

`U.S. Patent
`
`5,596,329
`
`Jan. 21, 1997
`
`Sheet 11 of 17
`
`
`
`
` g”
`
`ORTHOGONAL BEAM
`PATTERN WITH
`ANGULAR DIVERSITY
`
`STANDARD ORTHOGONAL
`BEAM PATTERN
`
`Ford Motor Co.
`Exhibit 1027
`Page 012
`
`Ford Motor Co.
`Exhibit 1027
`Page 012
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 12 of 17
`
`5,596,329
`
`Fig. 14 (a)
`
`INPHASE
`
`Fig. 14 (b)QuaDRATURE
`
`BEAM 3
`
`60
`
`61
`
`BEAM 2
`
` 59
`
` BEAM SPLITTER
`58 58
`
`BEAM SPLITTER
`
`FROM TX
`
`FROM TX
`
`Fig. 14 (ce
`
`NON- ERP LIMITED IMPROVED
`SIGNAL USING TWO INPHASE
`
`ERP LIMITED IMPROVEMENT
`USING 90° OFFSET BETWEEN
`TWO TRANSMIT BEAMS
`
`TRANSMIT BEAMS
`
`
`oo DUAL TX BEAMS
`
`
`ORIGINAL COVERAGE
`PATTERN WITHOUT
`
`Ford Motor Co.
`Exhibit 1027
`Page 013
`
`Ford Motor Co.
`Exhibit 1027
`Page 013
`
`

`

`5,596,329
`
`Page 014
`
`Ford Motor Co.
`Exhibit 1027
`Page 014
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 14 of 17
`
`|
`
`5,596,329
`
`Fig. 15 (c)
`
`SELECTED BEAMS
`AT TIME te
`
`BASE STATION
`
`BEAM NUMBER SELECTED
`
`
`
`
`MOBILE CHANNEL ALLOCATION |
`
`
`
`
`B18
`ms1 ALLOCATED CHANNEL1
`
`
`ms2 ALLOCATED CHANNEL2
`HANDED OFF TO
`
`ADJACENT CELL
`
`
`
`B4
`ms3 ALLOCATED CHANNEL3
`
`
`ms4 ALLOCATED CHANNEL4
`B7
`
`
`
`
`TIME t1
`
`
`
`TIME t2
`
`Ford Motor Co.
`Exhibit 1027
`Page 015
`
`Ford Motor Co.
`Exhibit 1027
`Page 015
`
`

`

`US. Patent
`
`5,596,329
`
`Jan. 21, 1997
`
`Sheet 15 of 17
`
`YiyYgory
`
`GyKO
`
`Ford Motor Co.
`Exhibit 1027
`Page 016
`
`

`

`U.S. Patent
`
`Jan. 21, 1997
`
`Sheet 16 of 17
`
`5,596,329
`
`
`
`
`
`
`
`
` aispw
`
`
`LATS
`
`Fig. 17 (a)
`
`Fig. 17 (b
`
`Fig. 18
`
`FAR OUT
`INTERFERENCE
`
`:
`INTERFERENCE
`
`Ford Motor Co.
`Exhibit 1027
`Page 017
`
`Ford Motor Co.
`Exhibit 1027
`Page 017
`
`

`

`
`
`Ford Motor Co.
`Exhibit 1027
`Page 018
`
`

`

`5,596,329
`
`1
`BASE STATION ANTENNA ARRANGEMENT
`
`BACKGROUND OF THE INVENTION
`
`2
`intended to convey the meaning of having radiation cover-
`age over the area corresponding to the required geographic
`area ofthe cell.
`
`This invention relates to a base station antenna arrange-
`ment, for use in a Cellular Radio communications system,
`which shall hereafter be referred to as a smart antenna.
`
`5
`
`BACKGROUND ART
`
`TECHNICAL FIELD
`
`39
`
`Some of the potential benefits of narrow beam antennas,
`for cellular radio, have been recognised in the literature, see
`for example “A Spectrum Efficient Cellular Base Station
`19 Antenna Architecture”,
`5S. C. Swales and M. A. Beach,
`Cellular radio systems are currently in widespread use~~Personal & Mobile Radio Communications Conference,
`throughout
`the world providing telecommunications to
`Warwick, 1991 and “Proposed Advanced Base Station
`mobile users. In order to meet the capacity demand, within
`Antennas for Future Cellular Mobile Radio Systems”, W.S.
`the available frequency band allocation, cellular radio sys-
`Davies, R. J. Long and E. Vinnal, Australian Telecomms
`tems divide a geographic area to be covered into cells. Atthe ,, Research, Vol. 22, No. 1, pp 53-60. Within current systems
`centre of each cell is a base station,
`through which the
`the manner in which directive antennae are used allows
`mobile stations communicate. The available communication
`relatively small benefits to be obtained. The useofdirective
`channels are divided between the cells such that the same
`antennas in current cellular radio systems is based on the
`group of channels are reused by certain cells. The distance
`principle of sectorisation as illustrated in FIG. 2. The main
`between the reused cells is planned such that the co-channel 29
`sources of interference, in a cellular system, come from the
`interference is maintained at a tolerable level.
`so called first tier reuse cells. An omni-directional base
`When a newcellular radio system is initially deployed,
`station antenna will receive interference from all six first tier
`operators are often interested in maximising the uplink
`reuse cells, FIG. 2a. If an antenna with nominally 120°
`(mobile station to base station) and downlink (basestation to
`beamwidthis used, correspondingto a tri-sectored configu-
`mobile station) range. The ranges in many systems are 5 ration, interference will be reccived from only twofirst tier
`uplink limited due to the relatively low transmitted power
`reuse cells, FIG. 2b. If an antenna with 60° beamwidth is
`levels of hand portable mobile stations. Any increase in
`used, corresponding to a hex-sectored configuration, inter-
`range meansthat less cells are required to cover a given
`ference will be received from only one ofthefirst tier cells,
`geographic area, hence reducing the numberofbasestations
`FIG.2c. In sectorised cells the cellular radio transceivers at
`and associated infrastructure costs.
`the basestation are only connectedto one sector (or antenna)
`When a cellular radio system is mature the capacity
`and cannot be used in other sectors within the samecell.
`demand can often increase, especially in cities, to a point
`The sectorised approach to the use of directive antennas
`where more, smaller size cells are needed in order to meet
`has reachedits useful limit at 60° beamwidth and can go no
`the required capacity per unit area. The process used to
`further. There are two key disadvantages of the approach:
`create these smaller cells is known as cell splitting. Any 35
`a) The cellular radio transceivers are dedicated to particular
`technique that can provide additional capacity without the
`sectors that leads to significant levels of trunking ineffi-
`need forcell-splitting will again reduce the number of base
`ciency. In practice this means that many more transceivers
`station sites and associated infrastructure costs. The antenna
`are needed at the base station site than for an omni-
`used at the basestation site can potentially make significant
`directional cell of the same capacity.
`improvements to the range and capacity of a cellular radio 40 b) Each sector is treated by the cellular radio network (i.e.
`system. The ideal base station antenna pattern is a beam of
`the base station controller and mobile switches) as a
`narrow angular width as shownin FIG. la. The narrow beam
`separate cell. This means that as the mobile moves
`is directed at the wanted mobile, is narrow in both the
`between sectors, a considerable interaction is required,
`azimuth and elevation planes, and tracks the mobile’s move-
`between the base station and the network, to hand off the
`ments. When compared to an omni-directional antenna, such 45
`call, between sectors of the same base station. This
`a beam will have the dual benefits of having high gain,
`interaction, comprising signalling and processing at the
`leading to increased range in thermal noise limited initial
`base station controller and switch, represents a high
`deployments, and rejecting interference from co-channel
`overhead on the network and reduces capacity.
`reuse cells allowing higher capacity without cell splitting in
`A standard cellular radio system is comprised of several
`mature deployments. The narrow beam reduces interference 50
`layers, as shown in FIG. 3. A Mobile Switching Centre
`in a balanced manner on the uplink and downlink. On the
`(MSC)is the interface between the cellular system and other
`uplink the base station receiver is protected from interfer-
`networks, e.g. PSTN, Public Switched Telephone Network
`ence generated by mobile station transmitters in the co-
`or ISDN,Integrated Services Digital Network. Each MSC
`channel reusecells, FIG. 1b. On the downlink the mobile is
`controls several Base Station Systems (BSS), which in some
`unlikely to be in the beamsof the base station transmitters 55
`systems, such as GSM or PCS, are further divided into a
`in the co-channel reuse cells. The extent of the advantage of
`Base Station Controller (BSC) which controls several Base
`a narrow beam antenna over an omni-directional antennais
`Transceiver Stations (BTS). Each BSS communicates with
`a function of the beamwidth. The narrower the beamwidth
`several Mobile Stations (MS). At the MSClevel there are
`the greater the advantage, but this must be traded off against
`also other facilities such as Operations and Maintenance
`the increased size and complexity of the antenna. Although 60
`(OMC) and Network Management (NMC).
`the narrow beam is formedat radio frequencies (typically in
`In this system the calls are allocated to transceivers at
`the 900 or 1800 MHz bands) it can usefully be visualised as
`basebandin the cellular radio network,at either the BSC, if
`analogous to a laser beam that emanates from the base
`available, or at the MSC, as shown in FIG. 4a. Any change
`station and tracks the mobiles. When contrasted with an
`required in the call
`to transceiver allocation has to be
`omni-directional antenna, this clearly creates a high quality 65
`signalled through the network, maybeasfar as the MSC and
`back again. This represents a heavy loading on the signalling
`transmission path with minimal interference. For the pur-
`poses of this document the use of the word “omni” is
`network and a time delay whilst it occurs. The basic concept
`
`Ford Motor Co.
`Exhibit 1027
`Page 019
`
`Ford Motor Co.
`Exhibit 1027
`Page 019
`
`

`

`5,596,329
`
`/
`provided a
`
`p
`
`4
`3
`means for combining the outputs of the plurality of
`of a smart antenna is disclosed in European Patent Appli-
`cation No. 92 309 520.2. A smart antenna as referred to
`receive amplifiers, and
`hereinafter comprises a plurality of antenna arrays each
`switching means for applying the combined receive sig-
`capable of forming a multiplicity of separate overlapping
`nals to the rf. transceiver handling the given call; and
`for transmitting 1.f. signals for the given call there is
`narrow beams in azimuth, the arrays being positioned such 5
`provided a single power amplificr for applying the
`that the totality of beams formed by the arrays provides a
`transceiver transmit signal to an individual one of the
`paremaers! omdirectional ae inazimuth, azimutn
`beams.
`and elevation beamforming meansfor each array, a plurality
`According to a fifth aspect of the invention the smart
`of rf. transceivers each for transmitting and receiving rf.
`10 antenna includes means for operating the antenna arrays
`signals for one or morecalls, switching matrix means for
`whereby individual narrow overlapping beamsare utilised
`connecting each transceiver with one or otherof the arrays
`for exchangeof rf. signals with individual remotestations in
`via the beamforming means, control means for controlling
`the areas covered by the respective narrow beams and
`the switch matrix means whereby a particular transcciveris
`simultaneously the totality of the multiplicity of narrow
`connected to a particular array, via the beamforming means,
`to exchange rf. signals with a remote station located in the 15 overlapping beams are utilised collectively to provide an
`arca covered by one of the narrow beams.
`omni-directional antenna radiation pattern.
`SUMMARY OF THE INVENTION
`According to a sixth aspect of the invention the smart
`antenna includes means for operating two or more non-
`collocated narrow beamwidth antennaarrays to form jointl
`er
`jointly
`20 a broad beamwidth antenna radiation pattern wherein the
`time averaged antenna pattern is substantiallynull free.
`According to a seventh aspect of the invention the smart
`antenna includes communication link means for communi-
`cation with a base station network whereby, in addition to
` ~ telecommunications message traffic passing through the
`an een oaneatenMeath canbe
`chan
`Ww
`insama
`:
`
`present invention there is
`to the
`According
`p
`8
`smart antenna comprising
`a plurality of antenna arrays each capable of forming a
`multiplicity of separate overlapping narrow beamsin
`azimuth,
`the arrays being positioned such that
`the
`totality of beams formed by the arrays provides a
`substantially omni-directional coverage in azimuth;
`azimuth and elevation beamforming meansfor each array;
`é
`:
`—
`a plurality of rf. transceivers each for transmitting and
`receiving rf. signals for one or morecalls;
`switching matrix means for connecting each transceiver 30
`with one or other of the arrays via the beamforming
`BRIEF DESCRIPTION OF THE DRAWINGS
`means,
`Embodiments of the invention will now be described with
`control means for controlling the switch matrix means
`reference to the accompanying drawings, in which:
`.
`whereby a particular transceiver is connected to a jg_FIGS. 1a and 10illustrate schematically the use of a
`particular array, via
`the
`beamforming means,
`to
`narrow beam antenna to communicate between a base
`exchange rf. signals with a remote station located in
`station and a mobilestation,
`phearea covered by one of the narrow overlapping
`FIGS. 2a-2c illustrate schematically the principle of
`sectorisation of a base station,
`2
`means for selecting for a given call more than one of the
`FIG. 3 is a block diagram of the main elements of a
`best received signals from the multiplicity of narrow “0 cellular system.
`overlapping beams; and
`as
`.
`.
`.
`.,
`.
`.
`.
`FIGS. 4a and 46illustrate the differences in call handling
`soemeangtocfonma.tagierevolveelpnal potterthext
`between a conventional cellular system and one using a
`smart antenna,
`”
`:
`:
`
`
`
`transceiver for the given call. FIG. 5 isablock di45 f th in el Fab
`
`
`
`
`
`
`According to one aspect of the invention the smart =fo1992)q DIGG uAprany Qt the: Maiiclements OL ad base
`
`
`
`
`antenna includes means for exchanging with a network
`‘Staton,
`;
`within which the smart antenna arrangementis incorporated
`FIGS. 6a and 6b are diagrams of the constituents of a
`information relating to the position and movement of a
`multiple narrow beam base station,
`remote station located within the area of coverage of the ,,
`FIG.7 illustrates the basic principle of a switching matrix,
`smart aheey rae h
`th
`FIG. 8 illustrates schematically the use of an interference
`the smart
`According to a second
`aspect of the invention
`detector,
`anteniad nclides means ter feenenising Unique identiier
`FIG.9 illustrates schematically the use of assisted han-
`a veeponies in call signals passing through the
`dover management,
`an ona any detect
`for
`discriminating
`b
`FIG. 10 is a block diagram of the communication link
`Soooantedcalla iseaAvesthedwalldice,alesine
`between the smart antenna and therest of a cellular system,
`:
`: ae :
`FIG.11 illustrates pictorially the interfacet radiation pat-
`e
`said unique identifier signals.
`f
`1tif,
`Aleut
`ith
`and
`without
`th
`¢
`According to a third aspect of the invention the smart
`oa sia EnPE
`EGELEC! SysteTl WAL
`ae, WanOUE
`THe Use
`;
`antenna includes meansforsplitting the transmission output gq P88 2OPPME>
`of a given transceiver into two identical signals prior to
`FIGS. 1a-12c are diagramsof different embodiments of
`transmission power amplification and transmitting said sig-
`phase hopping,
`nals in two adjacent narrow overlapping beams.
`FIGS. 13a and 136illustrate schematically the principles
`pp
`3
`Pp
`According to a fourth aspect of the invention the smart
`of angular diversity,
`antenna includes
`FIGS. 14a-14c are diagrams of different embodimentsof
`the dual transmit beam system with an illustration of the.
`a plurality of receive amplifiers one for each beam of an
`antenna array,
`relative radiation pattern improvements to be found,
`
`55
`
`65
`
`Ford Motor Co.
`Exhibit 1027
`Page 020
`
`Ford Motor Co.
`Exhibit 1027
`Page 020
`
`

`

`5,596,329
`
`5
`FIGS. 15a-15c illustrate the operation of a multiple
`narrow beam basestation,
`FIGS. 16a and 16b illustrate schematically the reduced
`overlap at differing cell radii boundaries using cell dimen-
`sioning,
`FIGS. 17a and 17b illustrate schematically the flexibility
`in base station location by the use of cell dimensioning,
`FIG. 18 illustrates schematically the use of cell dimen-
`sioning to reduce interference problems, and
`FIG.
`19illustrates schematically the use of cell dimen-
`sioning to avoid congestion.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`The main elements of a smart antenna as shownin FIG.
`5 comprise a mast, tower or building 10 supporting the
`antenna array(s) 12 and associated antennaelectronics unit
`14, which includes beamformers, diplexers and amplifiers.
`The antenna electronics unit 14 is connected via a cabin
`electronics unit 16 to the base station 18 that is under the
`control of a base station controller 20. The smart antenna
`system replaces the conventional passive antenna normally
`attached to the base station. The use of electronics in the
`mastheadallowsthe call switching to be carried out between
`the transceivers and antennas within the smart antenna, as
`shown in FIG. 4b. The switching now occurs on the rf.
`signals and only requires local control from the attached
`base station. This requires a new interface link 17 to be
`established between the base station and the smart antenna
`system. The previous baseband information is no longer
`required, reducing the loading on the signalling through the
`cellular radio network. It is replaced by rf. assignment
`information on the new interface link between the base
`station and smart antenna. This interface is also used to
`convey control information from the MSC, OMC and NMC
`parts of the cellular system.
`For the purposesofthis description the term “base station
`network”is used to describe all parts of the cellular system
`prior to the smart antenna and its interface link, e.g. the
`radio, base station controller, mobile switching centre,
`operations and maintenance and network management.
`The detailed constituents of the smart antenna are shown
`in FIG. 6. The masthead antenna electronics is shown in
`FIG.6a and the cabin electronics in FIG. 6b. Only one of the
`antenna arrays is depicted. Each antenna array 40 comprises
`a conventional array of individual antenna elements 42
`arranged in rows and columns. Each column of elementsis
`energised via an elevation beamforming network 44. Each
`elevation beamforming network combinesthe elements of a
`column to a single feed point. The amplitude and phase
`relationships of the rf. signals coupled to the elevation
`beamformer determine the elevation beam pattern of the
`antenna for both transmit and receive. Each elevation beam-
`former is coupled to the azimuth beamformer 46. The
`azimuth beamformer has multiple ports for both transmit
`and receive, one for each elevation beamformer. The phase
`and amplitude relationship of the 1.f. signals coupled to the
`elevation beamformers contro] the azimuth beam pattern for
`both transmit and receive. As the azimuth beamformeris
`prior to the low noise amplifiers on the receive path it must
`be optimised for low loss in that path. One well-known type
`of beamformeris the Butler matrix.
`
`The transmit and receive signals for the azimuth beam-
`formerare coupled to the beamformervia individual diplex-
`ers 48. Filters that cover just the transmit or receive fre-
`
`10
`
`25
`
`30
`
`6
`quency bands respectively can be used for this purpose. In
`the transmit path the diplexers 48 are fed via a combiner 50
`from separate single carrier power amplifiers 52. These
`amplify the rf. signals up to the power levels required for
`transmission. In the receive path the diplexers 48 feed
`separate substantially identical low noise amplifiers 62, one
`for each azimuth beam. The low noise amplifiers are
`required to amplify the weak received r.f. signals prior to any
`system losses to establish a low noise figure (high sensitiv-
`ity) in the subsequent receive path.
`In the receive path, signals are passed from the low noise
`amplifiers 62 to the receive splitter 74. On the transmit side,
`signals are passed to the single carrier transmit amplifiers
`from cell shaping attenuators 54. There is one cell shaping
`5 attenuator per transmit amplifier. All attenuators in any one
`beam areset to the same value to give a new beam template
`across all frequencies. This sets the maximum range in a
`particular direction, however the power required to reach a
`particular mobile in the beam can be reduced from this if
`necessary. The attenuators are controlled by the operator via
`the masthead control electronics. The cell shaping attenua-
`tors are situated prior to the amplifiers, to enable low power
`standard attenuators to be used. By placing them prior to the
`combinerthe intermodulation performance is improved, due
`to each being at a single frequency.
`Signals are passed from the transceivers 84 to the cell
`shaping attenuators, by a switching system, via an optional
`phase hopping module 66. This ensuresthat all transmittcrs
`can be connected to any beamformer input, however only
`one transmitter is connected to any one of the single carrier
`poweramplifiers, at any time. The switching system com-
`prises several levels of switchingor splitting, which ensurcs
`primarily maximum redundancy on the omni path and
`secondarily some redundancyin the traffic paths. The trans-
`ceivers 84, if required can be input to an n*n transmit switch
`matrix 78, where n is equal to the numberoftransceivers.
`The transmit switch matrix allows any one input to be
`connected to any one output, but not more than one inputto
`any one output simultaneously. This allows for redundancy
`should any cable in the mast fail, however the same function
`can be accomplished by the BTS if a suitable command
`interface exists. A combination of switches and splitters 56,
`58, 68 is used to ensure that the omni path is routed to every
`beam, whilst a single traffic channel only goes to one beam.
`This switching andsplitting function may be placedeither at
`the top or the bottom of the mast or a combination of both
`as shownin FIG.6. The preferred methadis to have the main
`facet switches 68 at the bottom of the mast and then each
`transceiver path is split to every beam, via the beam splitter
`58, where the amplifier select switch matrix 56 switches off
`the beams not required. This makes the implementation of
`the dual transmit beam concept far easier and ensures that
`the lower reliability components are in the cabin where
`access is easier.
`
`45
`
`50
`
`55
`
`60
`
`65
`
`The transmit, receive and amplifier select switch matrices
`comprise an x.f. cross-bar switch that allowsany ofits inputs
`to be connected to any of it’s outputs. The switch matrix
`design is such that any numberof transmitters or receivers
`can be connected simultancously to any one beamformer
`port, thus, if necessary, all the transmitters can be connected
`to one beam port at a given time. Likewise all the receivers
`can be connected,if necessary, to the same beam port at the
`same time. In practice, should there be more transceivers
`than a single beam can handle, the numberof transmitters
`that can be connected to the beam port is limited by the
`number of Tx power amplifiers 52. The switch matrices are
`operated under the control of a control processor 80. A
`typical switch matrix structure is illustrated in FIG.7.
`
`Ford Motor Co.
`Exhibit 1027
`Page 021
`
`Ford Motor Co.
`Exhibit 1027
`Page 021
`
`

`

`5,596,329
`
`7
`The receive splitter 74 ensures thal all incoming signals,
`from each beam, are sent to the interference discriminator
`70; the parallel receivers 72 and both the main and diverse
`reccive switch matrices 82.
`
`8
`thus reducing the loading on the base station
`quicker,
`controller. Having chosen the correct cell, with a conven-
`tional omni receiver there is no advantage to knowing the
`approximate azimuth position of a mobile within that cell,
`however in a multiple beam antenna each beam must be
`.
`a
`:
`)
`The interference discriminator 70 is used to identify 5
`monitored to find the one containing the mobile. It
`is
`whether or not the incoming signal is from a mobile in its
`therefore a great advantage to know the approximate beam
`own cell, or onc of a nearby cell or any other spurious
`into which a mobile will appear, so that the order in which
`source. The parallel receivers only assess signal strength,
`the beams are analysed can be weightedlo give priority to
`however, one of the strongest signals may not be from a
`jy the knowndirection. FIG. 9 shows a mobile passing through
`mobile within the cell, as shown by the direct path signal
`cell 1 and into cell 2. The tracking algorithm of the smart
`from MS2 in FIG.8.If these errant signals are not identified,
`antenna in cell 1 monitors the mobile’s progress through
`it can leadto errors in the processing within the basestation.
`beams 12, 11, 10 and 9 and can then give a quite accurate
`All
`transmissions between a mobile and a base station
`prediction to cell 2 that the mobile will appear in one of
`contain a fixed pattern knownasa training sequence, every
`base station within a given area has its own unique training c beams 18, 19 or 20.
`sequence, The interference discriminator selects one of the
`The main and diverse receive switch matrices, operate
`beams,
`in cach nese and searchesL the corte
`under the control of the control proccssor, on information
`Sequence wat mathe Tecelved
`signa’, usually using correla”
`derived from the parallel receivers, and select the strongest
`tiontechniques for digital signals. The beam that is selected
`and secondstrongestsignals, respectively. Thesesignalsare
`18 dictated by the control PIOCESSOL, based on information 29
`then coupled by rf. bus paths to the main and diverse ports
`received from the receive switch matrices and the interfer-
`of the bank oftransceivers 84, one for each channel to be
`ence discriminator. Tt does not necessarily look at every
`provided by the base station, where they are input to a
`beam, only those considered to be the most likely contend-
`maximal ratio combiner, of the type described in Mobile
`ers. The use of an interference discriminator is one of the
`Communications Systems by J D Parsons et al, Blackie
`features of the ae oroadenSten inch allows the as
`1989. The transceivers are operated under the control of the
`TOGUSRGY’ (e-NSe DOSE © De ecreasee:
`base station controller 88, which also provides overall
`A bank of parallel receivers 72, one for each beam,allow
`control for the switch matrix control processor 80.
`every receive channel
`to be monitored om every: beam
`The transceiver control bus 86 provides the communica-
`simultaneously. For each channel the receivers measure the
`tion Tink betweenthe base station and the smart antenna, The
`quality of iis wanted mobile signal present on each beam. 35 communication link will be comprised of several buses,
`The information on whichis the ‘bes!’ beam is passed to the
`“hose format will vary accordingto the type of basestation
`control processor.The quality measure used by the receivers
`to which the smart antennais attached. Wherever possible
`will Sate Gepending in, thie pamela celui system con-
`the bus str