WO2000026687A1 - Localisation d'une unite eloignee dans un systeme de communication - Google Patents

Localisation d'une unite eloignee dans un systeme de communication Download PDF

Info

Publication number
WO2000026687A1
WO2000026687A1 PCT/US1999/021963 US9921963W WO0026687A1 WO 2000026687 A1 WO2000026687 A1 WO 2000026687A1 US 9921963 W US9921963 W US 9921963W WO 0026687 A1 WO0026687 A1 WO 0026687A1
Authority
WO
WIPO (PCT)
Prior art keywords
power
base station
remote unit
periodically
transmission
Prior art date
Application number
PCT/US1999/021963
Other languages
English (en)
Inventor
Yossi Zilberfarb
Danie N. Nissani
Itzhak Shperling
Original Assignee
Motorola Inc.
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 Motorola Inc. filed Critical Motorola Inc.
Publication of WO2000026687A1 publication Critical patent/WO2000026687A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/28—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
    • H04W52/283—Power depending on the position of the mobile
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/10—Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements, e.g. omega or decca systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices

Definitions

  • the present invention relates generally to wireless communication systems and, in particular, to a method and apparatus for remote unit location in a wireless communication system.
  • a remote unit's location within a wireless communication system may be determined using a trilateration method. According to such a method, distances between the remote unit and multiple base stations are calculated based on a measurement of a time delay of a signal traveling between the remote unit and each base station.
  • a prior-art method for calculating a remote unit's location is described in US Pat. No. 5,508,708 "METHOD AND APPARATUS FOR LOCA ⁇ ON FINDING IN A CDMA SYSTEM" by Ghosh et al. and incorporated by reference herein.
  • the uplink signal transmitted from the remote unit to multiple base stations is analyzed to determine propagation delay differences at each base station. From these propagation delay differences, a distance is calculated from each base station to the remote unit, and the location of the remote unit is determined.
  • propagation delay differences can be calculated at the remote unit from a downlink communication signal (e.g., pilot signal) transmitted by multiple base stations, and a distance from each base station can be calculated by the remote unit in order to determine its location.
  • a downlink communication signal e.g., pilot signal
  • a remote unit gets close to a base station, the base station's transmission is received stronger, and constitutes a strong interference to the signals received from far (neighbor) base stations. Because of this, there is an area around each base station where a remote unit will be incapable of receiving signals transmitted from other base stations. Thus a need exists for a method and apparatus for remote unit location in a communication system that is capable of allowing for a remote unit close to a base station to estimate its location.
  • FIG. 1 is a block diagram of a communication system in accordance with the preferred embodiment of the present invention.
  • FIG. 2 illustrates a Time Difference Of Arrival (TDOA) location technique in accordance with the preferred embodiment of the present invention.
  • FIG. 3 is a block diagram of a base station sector in accordance with the preferred embodiment of the present invention.
  • TDOA Time Difference Of Arrival
  • FIG. 4 is a flow chart illustrating operation of the base station of FIG. 1 in accordance with the preferred embodiment of the present invention.
  • FIG. 5 is a block diagram of a base station sector in accordance with an alternate embodiment of the present invention.
  • FIG. 6 illustrates operation of sectorized base stations in accordance with a preferred and alternate embodiment of the present invention.
  • a near-in base station periodically reduces a power of a downlink communication signal transmitted by the base station in order to aide in locating the remote unit.
  • a substantial part of the interference received by the remote unit is reduced, thus improving the detection of weak neighbor signals.
  • the remote unit can more accurately determine its location when the remote unit is close to the near-in base station.
  • the present invention encompasses a method for aiding remote unit location in a communication system.
  • the method comprises the steps of determining that a location of a remote unit needs to take place and periodically reducing a power of a transmission in order to aide in locating the remote unit when it is determined that the location of the remote unit needs to take place.
  • the present invention additionally encompasses a method for aiding remote unit location in a communication system.
  • the method comprises the steps of determining that a location of the remote unit needs to take place and determining a time period when neighboring base stations will be actively transmitting a downlink communication signal.
  • a power of a transmission from a base station is periodically reduced during the time period when neighboring base stations will be actively transmitting the downlink communication signal, in order to aide in locating the remote unit.
  • the present invention encompasses a base station comprising channel circuitry outputting a signal.
  • the base station additionally comprises a switch having the signal as an input and periodically outputting the signal having a reduced power during a time period when neighboring base stations are actively transmitting a downlink communication signal.
  • FIG. 1 is a block diagram of communication system 100 in accordance with the preferred embodiment of the present invention.
  • communication system 100 utilizes a Code Division Multiple Access (CDMA) system protocol as described in Cellular System Remote unit-Base Station Compatibility Standard of the Electronic Industry Association/Telecommunications Industry Association Interim Standard 95A (IS-95A), which is incorporated by reference herein. (EIA/TIA can be contacted at 2001 Pennsylvania Ave. NW Washington DC 20006).
  • CDMA Code Division Multiple Access
  • communication system 100 may utilize other analog or digital cellular communication system protocols such as, but not limited to, the Narrowband Advanced Mobile Phone Service (NAMPS) protocol, the Advanced Mobile Phone Service (AMPS) protocol, the Global System for Mobile Communications (GSM) protocol, the Personal Digital Cellular (PDC) protocol, or the United States Digital Cellular (USDC) protocol.
  • Communication system 100 includes base stations 101-103, and remote unit 113. As shown, base stations 101-103 are transmitting downlink communication signals 116. Although not shown, one of ordinary skill in the art will recognize that base stations 101- 103 are suitably coupled to necessary infrastructure equipment such as Centralized Base Station Controllers (CBSCs), Mobile Switching Centers (MSCs), and the like.
  • CBSCs Centralized Base Station Controllers
  • MSCs Mobile Switching Centers
  • remote unit 113 utilizes a Time Difference Of Arrival (TDOA) technique to perform the location measurement.
  • TDOA Time Difference Of Arrival
  • the observed time difference between pairs of signals (e.g., pilot signals) arriving at remote unit 113 from three or more base stations are used to compute the location of remote unit 113.
  • FIG. 2 Here, three BSs are shown as base station 201, base station 202, and base station 203.
  • Remote unit 204 by observing the time difference in arriving signals between base station pairs 201 - 203, 202 - 203, and 201-202 can establish the hyperbolae or "lines of position" (LOPs') indicated as LOPs 205-207.
  • LOPs' lines of position
  • the near-in base station 101 periodically reduces a power of downlink communication signal 116 transmitted by base station 101 in order to aide in locating remote unit 113.
  • a substantial part of the interference received by remote unit 113 is reduced, thus improving the Ec/Io ratio for detection of weak neighbor pilot signals.
  • Ec/Io is reduced for weak neighbor pilot transmissions, remote unit 113 can more accurately determine its location when the remote unit is close to a base station.
  • Io is the spectral density of the total received CDMA interference.
  • Ec/Io is the received signal to noise ratio at the spread spectrum high bandwidth.
  • FIG. 3 is a block diagram of a single sector of base station 101 of FIG. 1 in accordance with the preferred embodiment of the present invention.
  • Base station 101 comprises controller 301, pilot channel circuitry 303, traffic channel circuitry 305-309, other channel circuitry 311, switch 315, timer 313, summer 317, and modulator 319.
  • base station 101 is a Motorola SC9600 base station having three sectors, each covering 120 degrees.
  • Base station 100 utilizes multiple classes of channels defined for forward transmission.
  • the traffic channels are similar to existing CDMA traffic channels and are used for voice and signaling.
  • CDMA traffic channels are described in detail in IS-95A. As described in IS-95A, the transmission rate of this channel may vary dynamically.
  • soft handoff Simultaneous communication utilizing more than one traffic channel circuit 305-309 is supported utilizing traffic channel circuitry 305-309.
  • Pilot channel circuitry 303 is utilized to broadcast a pilot channel from base station 101.
  • Such a pilot channel is described in IS-95 A section 7.1.3.2 and is utilized to provide timing and phase synchronization to aid in subsequent demodulation of a transmitted signal.
  • Other channel circuitry 311 comprises all other channels utilized by base station 101 such as paging channels, access channels, . . . , etc. Operation of base station 101 in accordance with the preferred embodiment of the present invention occurs as illustrated in FIG. 4.
  • a determination is made by controller 301 that a location of a remote unit needs to take place. In the preferred embodiment of the present invention the determination is based on a location request being received from a regional entity such as a MSC, operations center, or perhaps within a connected network such as Public Switched Telephone Network (PSTN).
  • PSTN Public Switched Telephone Network
  • controller 301 directs switch 315 to periodically switch to an open position, causing transmission from the sector to be periodically reduced in power.
  • switch 315 is instructed to open (ceasing transmission) for a 20 ms period every two seconds.
  • the opening of switch 315 causes the transmission from base station 101 to be periodically attenuated by an attenuator.
  • an attenuator Such a base station sector is shown in FIG. 5.
  • the base station in accordance with the alternate embodiment of the present invention comprises attenuator 501.
  • switch 315 when switch 315 is instructed to open, transmisssions from base station 101 in accordance with the alternate embodiment, are attenuated by attenuator 501 prior to transmission.
  • base station lOlis shown comprising attenuator 501
  • attenuation may be accomplished in power amplifiers existing within channel circuitry 303-311.
  • all switches within base station 101 are directed to open or close during the same 20 ms time period when switches in neighboring cells are open.
  • all sectors of base station 101 transmit, or cease from transmitting downlink communication signal 116 simultaneously.
  • switch 315 is preprogrammed to open when switches operating in neighboring base stations, as well as switches operating in differing sectors of base station 101 are closed. Therefore, in both the preferred and alternate embodiments of the present invention all sectors operating within neighboring base stations 101-103 are synchronized so that during any 20 ms period, only predetermined sectors cease transmission.
  • base station 101 transmits a message to remote unit 113, instructing remote unit 113 to perform a location estimation.
  • remote unit 113 performs a location estimation via a TDOA technique.
  • base station 101 determines if it has received a location estimation for remote unit 113, and if not, the logic flow returns to step 407, otherwise the logic flow continues to step 409 where base station 101 passes the location estimation to the entity that requested the remote unit's location.
  • controller 301 instructs switch 315 to remain in a closed position, resuming normal CDMA transmission.
  • FIG. 6 illustrates operation of sectorized base stations 601-607 in accordance with the preferred and alternate embodiments of the present invention.
  • each base station 601-607 is divided into three 120 degree sectors 1- 21.
  • all sectors of a base station 601-607 cease transmission during the same 20 ms time period when location is desired.
  • a cell site as a whole, will attenuate its power during those time periods when neighboring cell sites, as a whole, are actively transmitting a downlink communication signal at full power.
  • all sectors of base stations 601-607 cease transmission for a 20 ms period every two seconds. This is illustrated in FIG.
  • 500 ms period 610 during 500 ms period 610, during a time period when a sector 1-21 ceases transmission, all other neighboring sectors are actively transmitting downlink communication signals. Likewise, during time periods when a sector 1-21 has increased its power, at least one sector 1-21 has reduced its power.
  • base stations may cease transmission of any channel without varying from the scope of the present invention.
  • power reduction means 315 is shown as comprising a switch, one of ordinary skill in the art will recognize that any means may be employed to periodically reduce, or cease transmission from an individual base station. It is the intent of the inventors that various modifications can be made to the present invention without varying from the spirit and scope of the invention, and it is intended that all such modifications come within the scope of the following claims and their equivalents.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Au cours des périodes pendant lesquelles une unité éloignée (113) souhaite réaliser une mesure de localisation, une station (101) de base à proximité réduit périodiquement (si possible jusqu'à zéro) la puissance d'émission du signal (116) de communication de liaison descendante émis par la station (101) de base sur une courte période afin de participer à la localisation de l'unité éloignée (113). La réduction périodique de la puissance du signal (116) émis par la station (101) de base à proximité permet de réduire une bonne partie des interférences reçues par l'unité éloignée (113), ce qui permet d'améliorer le rapport Ec/Io servant à détecter les signaux voisins de faible intensité. Cette réduction du rapport Ec/Io pour les émissions voisines de faible intensité permet à l'unité éloignée (113) de déterminer plus précisément sa localisation lorsque l'unité éloignée (113) se trouve aux alentours de la station (101) de base à proximité.
PCT/US1999/021963 1998-10-29 1999-09-21 Localisation d'une unite eloignee dans un systeme de communication WO2000026687A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US18270198A 1998-10-29 1998-10-29
US09/182,701 1998-10-29

Publications (1)

Publication Number Publication Date
WO2000026687A1 true WO2000026687A1 (fr) 2000-05-11

Family

ID=22669636

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/021963 WO2000026687A1 (fr) 1998-10-29 1999-09-21 Localisation d'une unite eloignee dans un systeme de communication

Country Status (1)

Country Link
WO (1) WO2000026687A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1452887A2 (fr) * 2003-02-27 2004-09-01 Hitachi Ltd. Procédé de détermination de la position d'un terminal mobile, système de localisation et dispositif de détermination de position
US6912395B2 (en) 2001-09-25 2005-06-28 Motorola, Inc. Network and method for monitoring location capabilities of a mobile station

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5584049A (en) * 1994-09-12 1996-12-10 Qualcomm Incorporated Apparatus and method for adding and removing a base station from a cellular communications system
US5943014A (en) * 1996-06-06 1999-08-24 Qualcom Incorporated Using a signal with increased power for determining the position of a mobile subscriber in a CDMA cellular telephone system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5584049A (en) * 1994-09-12 1996-12-10 Qualcomm Incorporated Apparatus and method for adding and removing a base station from a cellular communications system
US5943014A (en) * 1996-06-06 1999-08-24 Qualcom Incorporated Using a signal with increased power for determining the position of a mobile subscriber in a CDMA cellular telephone system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6912395B2 (en) 2001-09-25 2005-06-28 Motorola, Inc. Network and method for monitoring location capabilities of a mobile station
EP1452887A2 (fr) * 2003-02-27 2004-09-01 Hitachi Ltd. Procédé de détermination de la position d'un terminal mobile, système de localisation et dispositif de détermination de position
EP1452887A3 (fr) * 2003-02-27 2005-06-29 Hitachi Ltd. Procédé de détermination de la position d'un terminal mobile, système de localisation et dispositif de détermination de position
US7236879B2 (en) 2003-02-27 2007-06-26 Hitachi, Ltd. Method for calculating the position of a mobile terminal, positioning system, and position calculation apparatus

Similar Documents

Publication Publication Date Title
AU662241B2 (en) Method of transmitting timing advance data in GSM network
RU2105418C1 (ru) Способ предотвращения потери вызова при перераспределении канала связи в радиотелефонной системе
US6205326B1 (en) Method for determining when a communication unit is located within a preferred zone
KR100667411B1 (ko) 이동 무선 통신 시스템에서 가변 및 고정 순방향 링크 속도 제어를 위한 방법 및 장치
CA2332905C (fr) Unite d'emission-reception gsm equipee pour des mesures de temps d'arrivee
US5729826A (en) Mobile communication system with moving base station
KR100414411B1 (ko) 셀룰러 전화 시스템
US5483668A (en) Method and apparatus providing handoff of a mobile station between base stations using parallel communication links established with different time slots
EP0956715B1 (fr) Procédé de determination de la localisation d'un unite à distance dans un système de communication
US6826402B1 (en) Pilot beacon trigger enhancement with hysterisis
FI112765B (fi) Keskustenvälinen pehmeä kanavanvaihto solukkotietoliikennejärjestelmässä
US8515425B2 (en) Uplink carrier handoff and method for path loss based triggering of uplink carrier handoff
EP0872052B1 (fr) Procede et appareil de realisation de transfert dans un systeme de communication a spectre etale
KR20000069285A (ko) 코드 분할 다원 접속 셀룰러 통신 시스템의 이음매 없는 소프트 핸드오프
JP2008113467A (ja) ハンドオーバ方法及びセルラー通信システム
CA2185002A1 (fr) Extenseur cellulaire avec alignement de synchronisation pour systemes tdma
JP2001524793A (ja) 中継装置の使用を通してｃｄｍａシステムにおけるハンドオフを実行する方法および装置
JP2011024249A (ja) 送信方法及びセルラー無線システム
KR20020026384A (ko) 하나 이상의 트래픽 채널들을 위한 채널 할당들을포워딩하는 방법
JPH10503891A (ja) セルラー無線システムにおける接続の質を改善する方法及びベースステーション
KR100960829B1 (ko) 상이한 크기의 셀을 사용한 셀룰러 통신 네트워크,기지국, 단말 및 그 방법
CA2278830A1 (fr) Transferts dans une station de base de cellule concentrique a portee etendue
US5386456A (en) Method of reducing audio gap in downlink during handoff of cellular radiotelephone
EP1034678B1 (fr) Procede et systeme pour determiner la position de terminaux de radiocommunications mobiles
JPH09261711A (ja) スペクトル拡散通信方式を採用した移動通信システムとその移動局装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): BR JP KR

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase