EP1226723A1 - Verfahren und vorrichtung zur bereitstellung von softer-handoff für vorwärtsverbindung in einem cdma-kommunikationssystem - Google Patents
Verfahren und vorrichtung zur bereitstellung von softer-handoff für vorwärtsverbindung in einem cdma-kommunikationssystemInfo
- Publication number
- EP1226723A1 EP1226723A1 EP00978229A EP00978229A EP1226723A1 EP 1226723 A1 EP1226723 A1 EP 1226723A1 EP 00978229 A EP00978229 A EP 00978229A EP 00978229 A EP00978229 A EP 00978229A EP 1226723 A1 EP1226723 A1 EP 1226723A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- antenna array
- antenna
- recited
- softer handoff
- radiation patterns
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000005855 radiation Effects 0.000 claims abstract description 33
- 238000003491 array Methods 0.000 claims abstract description 13
- 239000011159 matrix material Substances 0.000 claims description 6
- 230000010267 cellular communication Effects 0.000 claims description 4
- 239000000969 carrier Substances 0.000 claims description 2
- 230000015556 catabolic process Effects 0.000 description 4
- 238000006731 degradation reaction Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000001413 cellular effect Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000002596 correlated effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/06—Reselecting a communication resource in the serving access point
-
- 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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
Definitions
- the present invention relates generally to communication systems, and more particularly, to a method and apparatus for providing forward link softer handoff in a code division multiple access (CDMA) communication system with antenna arrays, including narrow beam antennas.
- CDMA code division multiple access
- a cellular communication system typically includes one or more mobile stations or units, one or more base stations, and a mobile telephone switching office. Although only three cells 14 and two mobile stations 11 are shown in FIG. 1, a typical cellular network may comprise hundreds of base stations, thousands of mobile stations, and more than one mobile telephone switching office. Each cell will have allocated to it one or more dedicated control channels and one or more voice channels. In rural areas, the antenna towers 12 are commonly located at the center of a cell 14, thereby providing omni-directional coverage. In an omnidirectional cell, the control channels and the active voice channels are broadcast in all areas of the cell, usually from a single antenna. Where base stations are more densely located, a sectorized antenna system may be employed as in the prior art, and shown by the schematic diagram of FIG. 2.
- Sectorization requires directional antennas 20 having, for example, a 120 degree radiation pattern as illustrated in FIG. 2.
- Each sector 22 is itself a cell having its own control channels and traffic channels.
- channel may refer to a specific carrier frequency in an analog system, to a specific carrier /slot combination in a hybrid TDMA/FDMA system such as IS-54 and GSM, or to a specific PN code in a CDMA system such as IS-95.
- Existing narrow beam antenna arrays which may comprise uniform linear arrays including dipoles or patch elements and passive beam forming networks including Butler Matrices, typically produce several beams covering a sector. For example, a four beam pattern which includes four 30 degree beams covering a 120 degree sector or region is not uncommon. These beams typically have beam crossovers at approximately minus 4 dB, whereas sector antennas typically have beam crossovers at approximately minus 8 dB.
- beam-to-beam overlap within a narrow beam antenna pattern is significantly greater than sector-to-sector overlap within a sectorized antenna pattern, or even the overlap of beams at the edge of two narrow beam antennas.
- the forward link of adjacent beams produces interference in the beam overlap region.
- the beam overlap region of available narrow beam antenna panels is greater than the beam overlap region of available discrete antennas, because there is less control over the beams when using passive RF beam forming networks such as Butler Matrices.
- a typical beam-to-beam crossover in a narrow beam antenna pattern is approximately minus 4 dB, while sector antennas can be made narrower than the sectors they occupy, and crossover at approximately minus 8 dB. With more overlap, there is more degradation.
- narrow beam antennas are used for separate CDMA PN codes (i.e., one beam used for a current sector or PN), the additional overlap means more degradation on the forward link unless softer handoff is used.
- FIG. 1 is a schematic plan view illustrating an omni-directional cellular pattern as in the prior art
- FIG. 2 is a schematic plan view illustrating a sectorized cellular pattern as in the prior art
- FIG. 3 is a schematic view illustrating a talk channel in softer handoff with two adjacent beams of a narrow beam antenna as in the prior art
- FIG. 4 is a schematic view illustrating the utilization of spatially diverse narrow beam antennas with routing of the softer handoff talk channel into different diversity channels of adjacent beams in accordance with the present invention
- FIGS. 5A-5B are schematic views illustrating the utilization of discrete directive antennas or an array of antenna elements forming a phased array as an alternative to narrow beam antennas.
- FIG. 6 illustrates a logical flowchart of the method of providing forward link softer handoff in a CDMA communication system with spatially diverse antennas according to the method and system of the present invention.
- Narrow beam antenna 304 comprises Butler matrix 316 and a uniform linear array of antenna elements 320-326.
- talk channel 302 is connected to switch 306, which is connected to transmitters 308-314, respectively.
- an antenna pattern is formed by routing a signal from one of the transmitters 308-314 to Butler matrix 316, where it is thereafter distributed to antenna elements 320-326.
- signals transmitted by transmitters 308 and 310 are phased and distributed by Butler matrix 316 and antenna elements 320-326 such that the patterns produced will be beams A and B, respectively.
- Each of the other beams (C and D) are formed in a similar fashion.
- the talk channel 302 is routed via switch 306 to transmitters 308 and 310, which are coupled to the narrow beam antenna 304, producing beam patterns A and B, thereby placing the mobile station within two adjacent beams of the narrow beam antenna 304.
- beams A and B originate in a single narrow beam antenna panel, the beams have a higher correlation, thereby producing less path diversity benefit and resulting in a higher required transmit power allocation.
- FIG. 4 illustrates the utilization of spatially diverse antenna arrays 404 and 406 including rerouting the softer handoff talk channel 402 from a radiation pattern 415 of the first antenna array 404 into a radiation pattern 417 of the second antenna array
- talk channel 402 is coupled to softer handoff router 430, which is coupled to first antenna array transmitters 440-446 and to second antenna array transmitters 448-454, respectively.
- Router 430 includes first switching device 432 and second switching device 434.
- the talk channel 402 is rerouted via router 430 to transmitter 440 of first antenna array and to transmitter 450 of second antenna array, which are coupled to antenna elements 420-423 with appropriate phasing from beam former 416, and to antenna elements 424-427 with appropriate phasing from beam former 419, respectively, thereby effectively rerouting the softer handoff talk channel 402 from radiation pattern B of the first antenna array 404 into radiation pattern B of the second antenna array 406.
- the two diversity paths are less correlated, thereby improving the diversity gain.
- the first antenna array 404 is adapted to transmit a first plurality of radiation patterns 415 (A, B, C, D) defining a first coverage area.
- first antenna array 404 comprises a passive beam forming network 416 and antenna elements 420-423 of the uniform linear array 418.
- antenna elements 420-423 comprise patch elements or dipoles.
- first antenna array 404 is described as comprising a narrow beam antenna array including a passive beam forming network and a uniform linear array, it will be appreciated by those skilled in the art that other configurations may readily be utilized without departing from the spirit and scope of the present invention. For example, as illustrated in FIG.
- a plurality of discrete directive antennas such as sector antennas or dish antennas, may be used instead of the passive beam forming network /uniform linear array combination illustrated in FIG. 4.
- the passive beam forming network 416 illustrated in FIG. 4 may be instead an active electronic gain and phase weighting and summing to a linear or circular array as illustrated in FIG. 5B.
- a second antenna array 406 is adapted to transmit a second plurality of radiation patterns 417 (A, B, C, D) defining a second coverage area.
- second antenna array 406 comprises passive beam forming network
- first and second coverage areas overlap, and first antenna array 404 is spatially separated from second antenna array 406 by a predetermined distance, which in the preferred embodiment is approximately 10 to 15 feet horizontally.
- passive beam forming network 419 includes a Butler Matrix
- uniform linear array 428 includes a plurality of antenna elements 420, which in the preferred embodiment comprise patch elements or dipoles.
- second antenna array 406 is described as comprising a narrow beam antenna array including a passive beam forming network and a uniform linear array, it will be appreciated by those skilled in the art that other configurations may readily be utilized without departing from the spirit and scope of the present invention.
- a plurality of discrete directive antennas such as sector antennas or dish antennas, may be used instead of the passive beam forming network /uniform linear array combination illustrated in FIG. 4.
- the passive beam forming network may be used instead of the passive beam forming network /uniform linear array combination illustrated in FIG. 4.
- the passive beam forming network may be used instead of the passive beam forming network /
- FIG. 419 illustrated in FIG. 4 may be instead active electronic gain and phase weighting and summing to a linear or circular array as illustrated in FIG. 5B.
- each of the first and second antenna arrays comprises a narrow beam antenna and each of the first and second plurality of radiation patterns include a first plurality of adjacent beams and a second plurality of adjacent beams, respectively.
- each of the first and second plurality of radiation patterns include a first plurality of adjacent beams and a second plurality of adjacent beams, respectively.
- other antenna array configurations, and other radiation patterns may be utilized without departing from the spirit and scope of the present invention.
- alternate frequencies may be placed on alternate antenna panels, and a third carrier may be separated by two channel spacings, thereby allowing more efficient frequency combining.
- the present invention still provides two antenna arrays covering the same region, thereby allowing frequencies fl, f3, f5, etc. to be placed on the main panel, and frequencies f2, f4, f6, etc. to be placed on the diversity panel.
- the process begins at block 600, wherein the step of transmitting, from a first antenna array, a first plurality of radiation patterns defining a first coverage area is performed. Thereafter, as shown at block 602, the step of transmitting, from a second antenna array spatially separated from the first antenna array, a second plurality of radiation patterns defining a second coverage area, the first and second coverage areas overlapping, is performed. Thereafter, as shown at block 604, the step of rerouting a softer handoff talk channel from a radiation pattern of the first antenna array into a radiation pattern of the second antenna array is performed.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US42623399A | 1999-10-22 | 1999-10-22 | |
US426233 | 1999-10-22 | ||
PCT/US2000/028614 WO2001031941A1 (en) | 1999-10-22 | 2000-10-14 | Method and apparatus for providing forward link softer handoff in a code division multiple access communication system |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1226723A1 true EP1226723A1 (de) | 2002-07-31 |
EP1226723A4 EP1226723A4 (de) | 2002-10-25 |
Family
ID=23689913
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20000978229 Withdrawn EP1226723A4 (de) | 1999-10-22 | 2000-10-14 | Verfahren und vorrichtung zur bereitstellung von softer-handoff für vorwärtsverbindung in einem cdma-kommunikationssystem |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1226723A4 (de) |
CN (1) | CN1376364A (de) |
WO (1) | WO2001031941A1 (de) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2002356952A1 (en) * | 2001-11-15 | 2003-06-10 | Metawave Communications Corporation | Passive shapable sectorization antenna gain determination |
FR2855929A1 (fr) | 2003-06-03 | 2004-12-10 | Nortel Networks Ltd | Telecommunications mobiles avec antennes multisectorielles |
US8369424B2 (en) | 2006-07-14 | 2013-02-05 | Qualcomm Incorporated | Frequency selective and frequency diversity transmissions in a wireless communication system |
EP2892268B1 (de) * | 2012-10-12 | 2018-03-21 | Huawei Technologies Co., Ltd. | Verfahren, vorrichtung und basisstation zur verbesserung der benutzerkapazität auf dem physikalischen sektor |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995012296A1 (en) * | 1993-10-28 | 1995-05-04 | Qualcomm Incorporated | Method and apparatus for performing handoff between sectors of a common base station |
WO1998059512A1 (en) * | 1997-06-24 | 1998-12-30 | Telefonaktiebolaget Lm Ericsson | Sectorization of cellular cdma-system |
EP0895436A2 (de) * | 1997-07-31 | 1999-02-03 | Nortel Networks Corporation | Combinierte Mehrstrahl und Sektor Gruppenantenne |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5432780A (en) * | 1988-09-12 | 1995-07-11 | Motorola, Inc. | High capacity sectorized cellular communication system |
GB2281011B (en) * | 1993-08-12 | 1998-04-08 | Northern Telecom Ltd | Base station antenna arrangement |
JP3308835B2 (ja) * | 1996-12-06 | 2002-07-29 | 株式会社日立製作所 | 無線通信システム |
GB2320618A (en) * | 1996-12-20 | 1998-06-24 | Northern Telecom Ltd | Base station antenna arrangement with narrow overlapping beams |
US6122266A (en) * | 1997-02-19 | 2000-09-19 | Lucent Technologies Inc. | Multi-level sectorized CDMA communications |
US6104930A (en) * | 1997-05-02 | 2000-08-15 | Nortel Networks Corporation | Floating transceiver assignment for cellular radio |
US6167036A (en) * | 1998-11-24 | 2000-12-26 | Nortel Networks Limited | Method and apparatus for a sectored cell of a cellular radio communications system |
-
2000
- 2000-10-14 EP EP20000978229 patent/EP1226723A4/de not_active Withdrawn
- 2000-10-14 WO PCT/US2000/028614 patent/WO2001031941A1/en not_active Application Discontinuation
- 2000-10-14 CN CN00813484.7A patent/CN1376364A/zh active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995012296A1 (en) * | 1993-10-28 | 1995-05-04 | Qualcomm Incorporated | Method and apparatus for performing handoff between sectors of a common base station |
WO1998059512A1 (en) * | 1997-06-24 | 1998-12-30 | Telefonaktiebolaget Lm Ericsson | Sectorization of cellular cdma-system |
EP0895436A2 (de) * | 1997-07-31 | 1999-02-03 | Nortel Networks Corporation | Combinierte Mehrstrahl und Sektor Gruppenantenne |
Non-Patent Citations (5)
Title |
---|
HAI XIE ET AL: "Improved performance of a CDMA cellular system with macrocell diversity" UNIVERSAL PERSONAL COMMUNICATIONS, 1994. RECORD., 1994 THIRD ANNUAL INTERNATIONAL CONFERENCE ON SAN DIEGO, CA, USA 27 SEPT.-1 OCT. 1994, NEW YORK, NY, USA,IEEE, 27 September 1994 (1994-09-27), pages 56-61, XP010131568 ISBN: 0-7803-1823-4 * |
JUNG P ET AL: "Exploitation of intracell macrodiversity in mobile radio systems by deployment of remote antennas" SPREAD SPECTRUM TECHNIQUES AND APPLICATIONS PROCEEDINGS, 1996., IEEE 4TH INTERNATIONAL SYMPOSIUM ON MAINZ, GERMANY 22-25 SEPT. 1996, NEW YORK, NY, USA,IEEE, US, 22 September 1996 (1996-09-22), pages 302-307, XP010208582 ISBN: 0-7803-3567-8 * |
KLEIN A ET AL: "Known and novel diversity approaches in a JD-CDMA system concept developed within COST 231" PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, 1995. PIMRC'95. WIRELESS: MERGING ONTO THE INFORMATION SUPERHIGHWAY., SIXTH IEEE INTERNATIONAL SYMPOSIUM ON TORONTO, ONT., CANADA 27-29 SEPT. 1995, NEW YORK, NY, USA,IEEE, US, 27 September 1995 (1995-09-27), pages 512-516, XP010150939 ISBN: 0-7803-3002-1 * |
MOORTI T ET AL: "PERFORMANCE OF A FIXED-BEAM SYSTEM IN THE IS-95 CDMA FORWARD LINK" EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, EUREL PUBLICATION, MILANO, IT, vol. 9, no. 4, 1 July 1998 (1998-07-01), pages 361-370, XP000778099 ISSN: 1124-318X * |
See also references of WO0131941A1 * |
Also Published As
Publication number | Publication date |
---|---|
CN1376364A (zh) | 2002-10-23 |
WO2001031941A1 (en) | 2001-05-03 |
EP1226723A4 (de) | 2002-10-25 |
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