WO2004045227A1 - Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc - Google Patents

Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc Download PDF

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Publication number
WO2004045227A1
WO2004045227A1 PCT/CN2002/000800 CN0200800W WO2004045227A1 WO 2004045227 A1 WO2004045227 A1 WO 2004045227A1 CN 0200800 W CN0200800 W CN 0200800W WO 2004045227 A1 WO2004045227 A1 WO 2004045227A1
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WO
WIPO (PCT)
Prior art keywords
handoff
code
power
communications
cell
Prior art date
Application number
PCT/CN2002/000800
Other languages
English (en)
Inventor
William C. Y. Lee
Original Assignee
Linkair Communications, 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 Linkair Communications, Inc. filed Critical Linkair Communications, Inc.
Priority to AU2002340716A priority Critical patent/AU2002340716A1/en
Priority to PCT/CN2002/000800 priority patent/WO2004045227A1/fr
Priority to CN02829795.4A priority patent/CN1689347A/zh
Publication of WO2004045227A1 publication Critical patent/WO2004045227A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/16—Performing reselection for specific purposes
    • H04W36/20—Performing reselection for specific purposes for optimising the interference level
    • 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
    • H04W52/38—TPC being performed in particular situations
    • 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
    • H04W52/38—TPC being performed in particular situations
    • H04W52/40—TPC being performed in particular situations during macro-diversity or soft handoff

Definitions

  • the present invention relates to cellular telephone system.
  • the present invention relates to a novel system for controlling handoffs of mobile units among the communications of cell- site stations in a code division multiple access (CDMA) system. More specifically, The present invention relates to a method and system for providing a hard handoff in communications in a CDMA system.
  • CDMA code division multiple access
  • the soft handoff is a means of using diversity scheme so that the signal in the soft handoff region is enhanced and secured by taking the signals from both cells, the home cell and the target cell.
  • the two signals from two cells are called two fingers. Most often, there are more than two fingers involved due to many surrounding cells. In 3G systems, it can have up to seven fingers to be encountered during the soft handoff process. Therefore, the soft handoff process is very complicated. Furthermore, the system capacity is reduced due to the two signal channels used for serving one user in the handoff region. Sometimes, one-third of the capacity is lost because of the soft handoff system.
  • the present invention provides a method and system for providing a hard handoff in communications in a CDMA system.
  • the hard handoffs have to be talcing place in a system when all the traffic signals (channels) are orthogonal, such as by frequency divisions or time divisions.
  • FDMA systems such as AMPS
  • all the traffic signals are on different frequencies except the same frequency re-used at a proper distance away.
  • the GSM system is a TDMA system.
  • it can use hard handoffs.
  • window properties -t ! ⁇ ⁇ t, and -t 2 ⁇ ⁇ t 2 are required for eliminating ACI, so that the hard handoffs can take place.
  • Today several smart codes are found. However, they only consist of 32 codes with a window, -3t c ⁇ ⁇ 3t c where t c is the code chip interval. In order to identify the same set of 32 codes in different cells, different means of identifying cells are added on. Most of them are causing the whitening effect, i.e., destroying the correlation zero-window of two sets assigned to two adjacent cells. The ACI prevails and the hard handoff cannot be realized.
  • DOC Distinctive Orthogonal Code
  • a method for providing a hard handoff in communications in a CDMA system comprising the steps of: increasing the signal power of home cell before the handoff; increasing the power of the code channel in the target cell and dropping the code channel in the home cell during the handoff; readjusting the power of the new code channel according to E b jl 0 ; shifting the new code for n ⁇ T c if the E b /l 0 is poor for the new code channel after handoff. wherein the said handoff can be soft handoff or hard handoff.
  • the size of two cells is not necessarily equal.
  • the said handoff can be applied to the sector-to-sector handoff within a cell.
  • the code shift can be shifted to any value, plus or minus.
  • the power enhancement can be boosted up alone or go with the code shift.
  • the code shift can be shifted alone or go with the power enhancement.
  • a system for providing a hard handoff in communications in a CDMA system in a cellular telephone system in which a mobile user and another user communicate information signals there between via at least one of a plurality of geographically separated cells each defining a respective geographic service area, a system for directing communications between the said mobile users via the said at least one of cells as one mobile user changes cell service area, comprising: Handoffs; means for power enhancement; means for code shifts.
  • the present invention provides a substantial improvement over conventional cellular telephone systems by providing additional system reliability and quality in communications.
  • FIG.1(a) is hard handoff in FDMA/TDMA (no ACI);
  • FIG.1 (b) is soft handoff in CDMA (ACI exists);
  • FIG.2(a) is hard handoff in CDMA with a particular set of smart codes and power enhancement(Before handoff);
  • FIG.2(b) is hard handoff in CDMA with a particular set of smart codes and power enhancement(After handoff);
  • FIG.3(a) is DOC (Distinctive Orthogonal Code) without power enhancement;
  • FIG.3(b) is DOC with power enhancement ⁇ efore hard H.O.);
  • FIG.3(c) is DOC with power enhancement(After hard H.O.);
  • FIG.4 is a schematic view illustrating the code shift in accordance with the present invention.
  • a method for providing a handoff in communications in a CDMA system includes the following steps: increasing the signal power of home cell before the handoff; increasing the power of the code channel in the target cell and dropping the code channel in the home cell during the handoff; readjusting the power of the new code channel according to E b jl 0 ; shifting the new code for n ⁇ T c , if the E b /I 0 is poor for the new code channel after handoff.
  • the hard handoffs are used in FDMA or TDMA systems because there is no ACI.
  • the soft H.O. is used in CDMA systems because ACI exists due to the non-zero correlation window properties.
  • the particular set of smart codes DOC has the correlation properties as shown in Fig.2(a) and Fig.2(b) and Fig.2(c).
  • the present invention is to enhance the signal power in a short time just before the hard handoff. The effect is as follows:
  • the second step of the present invention is to increase the power of the code channel in the target cell and drop the code channel in the home cell during the hard handoff. After the hard handoff is completed, reduces the power of the code channel according to E b ]I 0 .
  • the size of two cells does not necessarily have to be equal.
  • the code shift can be shifted to any value, plus or minus, and the power enhancement can be boosted up alone or go with the code shift.
  • the code shift can be shifted alone or go with the power enhancement.
  • the code shift in accordance with the present invention can be used in any circumstance in order to reduce any kind of interference.
  • a system for providing a hard handoff in communications in a CDMA system in a cellular telephone system in which a mobile user and another user communicate information signals there between via at least one of a plurality of geographically separated cells each defining a respective geographic service area, a system for directing communications between the said mobile users via the said at least one of cells as one mobile user changes cell service area, comprising:Handoffs;means for power enhancement;means for code shifts.
  • the present invention provides a substantial improvement over conventional cellular telephone systems by providing additional system reliability and quality in communications.

Abstract

La présente invention concerne un procédé et un système pour réaliser un transfert entre cellules avec solution de continuité dans des communications à l'intérieur d'un système AMRC. Ce procédé comporte plusieurs opérations: augmentation de la puissance du signal de la cellule de référence avant le transfert de cellule; augmentation de la puissance du canal de code dans la cellule cible et abandon du canal de code dans la cellule de référence pendant le transfert entre cellules; remise à niveau de la puissance du nouveau canal de code en fonction du rapport Eb/Io; permutation circulaire du nouveau code jusqu'à n*Tc si le rapport Eb/Io; est mauvais par rapport au nouveau canal de code après le transfert entre cellules. L'invention apporte ainsi des améliorations notables par rapport aux systèmes téléphoniques cellulaires conventionnels dans la mesure où il augmente la fiabilité du système et la qualité des communications.
PCT/CN2002/000800 2002-11-11 2002-11-11 Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc WO2004045227A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU2002340716A AU2002340716A1 (en) 2002-11-11 2002-11-11 Method and system for providing a hard handoff in communications in a cdma system
PCT/CN2002/000800 WO2004045227A1 (fr) 2002-11-11 2002-11-11 Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc
CN02829795.4A CN1689347A (zh) 2002-11-11 2002-11-11 一种在cdma通信系统中提供硬切换的方法及系统

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2002/000800 WO2004045227A1 (fr) 2002-11-11 2002-11-11 Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc

Publications (1)

Publication Number Publication Date
WO2004045227A1 true WO2004045227A1 (fr) 2004-05-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2002/000800 WO2004045227A1 (fr) 2002-11-11 2002-11-11 Procede et systeme pour realiser un transfert entre cellules avec solution de continuite dans des communications a l'interieur d'un systeme amrc

Country Status (3)

Country Link
CN (1) CN1689347A (fr)
AU (1) AU2002340716A1 (fr)
WO (1) WO2004045227A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1740000A1 (fr) * 2005-06-27 2007-01-03 Siemens Aktiengesellschaft Procédé de transfert d'une liaison radio par commande de la puissance d'émission des stations de base
EP1887711A1 (fr) * 2006-08-07 2008-02-13 NTT DoCoMo, Inc. Dispositif de contrôle de communication radio, système de contrôle radio, et procédé de contrôle de communication radio

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998059432A2 (fr) * 1997-06-20 1998-12-30 Qualcomm Incorporated Procede et appareil de commande de l'adaptation de puissance dans un systeme de communications en boucle fermee
GB2358109A (en) * 2000-01-10 2001-07-11 Fujitsu Ltd Power control during soft handoff
CN1309845A (zh) * 1998-07-16 2001-08-22 艾利森电话股份有限公司 在基于码分多址的系统中用于硬切换的自适应功率容限
WO2001095521A2 (fr) * 2000-06-05 2001-12-13 Qualcomm Incorporated Procede et appareil permettant d'ameliorer la commande de puissance d'une liaison aval pendant un transfert souple

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998059432A2 (fr) * 1997-06-20 1998-12-30 Qualcomm Incorporated Procede et appareil de commande de l'adaptation de puissance dans un systeme de communications en boucle fermee
CN1309845A (zh) * 1998-07-16 2001-08-22 艾利森电话股份有限公司 在基于码分多址的系统中用于硬切换的自适应功率容限
GB2358109A (en) * 2000-01-10 2001-07-11 Fujitsu Ltd Power control during soft handoff
WO2001095521A2 (fr) * 2000-06-05 2001-12-13 Qualcomm Incorporated Procede et appareil permettant d'ameliorer la commande de puissance d'une liaison aval pendant un transfert souple

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1740000A1 (fr) * 2005-06-27 2007-01-03 Siemens Aktiengesellschaft Procédé de transfert d'une liaison radio par commande de la puissance d'émission des stations de base
EP1887711A1 (fr) * 2006-08-07 2008-02-13 NTT DoCoMo, Inc. Dispositif de contrôle de communication radio, système de contrôle radio, et procédé de contrôle de communication radio
US8249578B2 (en) 2006-08-07 2012-08-21 Ntt Docomo, Inc. Radio communication control device, radio communication control system, and radio communication control method

Also Published As

Publication number Publication date
AU2002340716A1 (en) 2004-06-03
CN1689347A (zh) 2005-10-26

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