WO1996038997A1 - Systemes de transfert intercellulaire pour reseaux telephoniques cellulaires numeriques - Google Patents

Systemes de transfert intercellulaire pour reseaux telephoniques cellulaires numeriques Download PDF

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Publication number
WO1996038997A1
WO1996038997A1 PCT/GB1996/001280 GB9601280W WO9638997A1 WO 1996038997 A1 WO1996038997 A1 WO 1996038997A1 GB 9601280 W GB9601280 W GB 9601280W WO 9638997 A1 WO9638997 A1 WO 9638997A1
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WO
WIPO (PCT)
Prior art keywords
base station
base stations
handover
downlink
mobile telephone
Prior art date
Application number
PCT/GB1996/001280
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English (en)
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WO1996038997B1 (fr
Inventor
Ying-Chun Lui
Original Assignee
Hong Kong Telecom Csl Ltd.
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 Hong Kong Telecom Csl Ltd. filed Critical Hong Kong Telecom Csl Ltd.
Priority to AU58290/96A priority Critical patent/AU701840B2/en
Priority to EP96919926A priority patent/EP0829179A1/fr
Publication of WO1996038997A1 publication Critical patent/WO1996038997A1/fr
Publication of WO1996038997B1 publication Critical patent/WO1996038997B1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/302—Reselection being triggered by specific parameters by measured or perceived connection quality data due to low signal strength
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/38—Reselection control by fixed network equipment

Definitions

  • the invention relates to handover arrangements for digital cellular telephone networks.
  • the communications transmitters and receivers are generally evenly dispersed geographically around the region of the network in an array at base stations and connected to a central network control station which serves to control
  • the central control station allocates frequencies and channels and selects appropriate base stations at the beginning of each telephone call for individual communications. Handover arrangements are
  • the central controller provided by the central controller to vary or alter the channels and frequencies to connect the telephones to communicate with different base stations during each call according to prevailing circumstances.
  • the central controller also monitors and records the calls for user
  • the base stations are arranged so as to provide areas of suitable transmission and reception over a number of hexagonal side by side areas or so-called "cells".
  • the carrier frequencies used by one cell is different to any carrier frequencies in an immediately adjacent cell but are the same as the frequencies used in another cell in the network somewhat remote and usually separated by a further two cells of the network.
  • a honeycomb type pattern of communication cells can be conveniently formed using say seven different sets of carrier frequencies.
  • the control station is capable and designed to transfer or handover the mobile telephone to communicate at appropriate different frequencies.
  • a handover arrangement for a digital cellular telephone network having a central controller and a number of mobile telephones, in which each telephone is arranged to continually measure and transmit downlink signal strength of a first base station and downlink signal strength measurements of a number of other selected base stations, and in which these signals are passed to the central controller which determines a C/I ratio and controls a handover of the mobile telephone from the first base station to another base station if this ratio falls below a predetermined value, where C equals the downlink signal strength of the first base station and I is a summation of the downlink signal strengths of other selected base stations.
  • a handover arrangement for a digital cellular telephone network having a central controller and a number of mobile telephones, in which each telephone is arranged to continually measure and transmit downlink signal strength of a first base station and downlink signal strength measurements of a number of other selected base stations, and in which these signals are passed to the central controller which determines a C/I ratio and controls a handover of the mobile telephone from the first base station to another base station provided this ratio is above a predetermined value, where C equals the downlink signal strength of potential handover target base station and I is a summation of the downlink strengths of the other selected base stations.
  • the downlink strengths may be measured on control channels of the network.
  • the selected base stations may comprise the base stations which are the nearest other base stations in the network having the same carrier frequency.
  • the selected base stations may be preselected other base stations geographically associated with the potential handover target base stations.
  • the downlink strengths of the selected base stations may be modified before being summated by selected quotients or scaling factors relating to previous calculations or measurements of the network.
  • the first base station is arranged to serve a special area of the network
  • two or more other remotely located base stations in the system may be selected to identify that a mobile telephone is in that special area, and the mobile telephone arranged to measure the downlink strength of signals from the two or more selected base stations and communicate the signal strengths to the first base station for onward transmission to the central controller.
  • a mobile telephone for the digital cellular telephone network including means for continuously periodically measuring the strength of downlink signals received from a first base station and the strengths of downlink signals received from a number of selected other base stations, and means for transmitting these measurements to the first base station.
  • the measuring means may be arranged to measure the strength of downlink signals from the surrounding base stations operating at the same carrier frequency.
  • the measuring means may be alternatively or additionally arranged to measure the strength of downlink signals from base stations that are preselected geographically associated with a potential handover target base station.
  • the measuring means may also be arranged to measure the strength of downlink signals from selected two or more geographically positioned relative to the potential handover target station.
  • Figure 1 is an idealised plan view of a cellular network
  • Figure 2 is another idealised plan view of a cellular network
  • Figure 3 is a plan view of part of a typical cellular networ ;
  • Figure 4 is a schematic side view of another cellular network.
  • Figure 5 is an idealised plan view of a cellular network having some cells with super re-use carrier frequencies.
  • Digital cellular mobile telephone networks are already known and typically each cell is arranged to transmit at three different carrier frequencies providing eight (time division multiplexed) channels per carrier frequency. Two channels of one of the carrier frequencies is used for control signals and the rest of the one carrier frequency and all the channels of the other two carrier frequencies are used for voice or data transmission, so-called "traffic".
  • the channels are arranged in pairs and one channel of each pair is used for transmission to a mobile telephone (downlink signals) and the other channel of the pair is used for transmission from the mobile telephone (uplink signals) .
  • the mobile telephone is normally connected for communications at first to its nearest cell and allotted a pair of channels by the central network controller for communication of traffic. This is done by exchanges of messages on the control channels in accordance with well- practised procedures already known.
  • each mobile telephone is arranged to periodically respond to signals from other cells and relay to the central controller via the cell radio links the signal strengths of signal received from the other cells (downlink signals) in a manner to be described below.
  • the purpose of receiving and measuring the strength of various downlink signals, including its own downlink signal, is to provide information that the central controller can use to "handover" the particular mobile telephone to another cell. This is to ensure that the quality of the communications remains satisfactory as conditions change which will usually be due to the mobile telephone moving closer to a neighbouring cell or possibly into a poor localised reception area of the cell presently in communication with the mobile telephone.
  • control channel frequencies are re-used every seven cells (Cl to C7) .
  • the normal traffic channels frequencies are re-used every four cells (VI to V4) .
  • level of re-use for the traffic channels is significantly higher than the level of re-use of the control channels but it will be noted that the "potential interferers" have control channels using different frequencies.
  • “Potential interferers” is used to identify the cells or base stations in the system using the same set of traffic channel frequencies, so that the signals from potential interferers are potentially strong enough to cause interference within the cell or base station area presently communicating with the mobile telephone.
  • the mobile telephone periodically measures the downlink signal strength of the serving base station and those of potential interferers. All measurement results are reported to the central controller which calculates the C/I ratio of the in-use radio link according to the following method :
  • L s downlink signal strength of the serving base station
  • L is1 downlink signal strength of the 1st potential interferer
  • L i ⁇ downlink signal strength of the 2nd potential interferer
  • the level of re-use of the traffic channel frequencies is the same as that of the level of re-use of the control channel frequencies.
  • the same traffic channels and the control channel are re-used every seven cells.
  • the mobile telephone When using the network in Figure 2, during the progress of a call the mobile telephone periodically measures the downlink signal strength of the serving base station and those of "reference" base stations. "Reference" base stations is used to identify a set of neighbouring base stations on different control-channel frequencies and are specially selected for estimating the signal level of likely interferers. .All these measurement results are reported to the central controller which calculates the approximate C/I ratio of the in-use radio link according to the following method:
  • L i ⁇ k ⁇ downlink signal strength of the kth potential interferer (to be estimated)
  • L s downlink signal strength of the serving base station.
  • L rk1 downlink signal strength of the 1st reference base station for the kth potential interferer.
  • L rk2 downlink signal strength of the 2nd reference base station for the kth potential interferer.
  • L rk ⁇ downlink signal strength of the xth reference base station for the kth potential interferer.
  • L i sk MAX [ ( L rkl * a. ) , ( L pk2 * a,) ( L rk ⁇ * a ⁇ ) ] where al, a2, ...., ax are fixed quotients or scaling factors.
  • the scaling factors are pre-set by prior measurements taken for network and provide necessary adjustment so that the composite signal contour of reference base stations after scaling is approximately equal to that of the kth potential interferer within the service area of the serving base station. This is illustrated in Figure 3.
  • C/I L s / (L js1 + L js2 + ... + L is
  • Base station A is planned to illuminate or serve a part of a road on a mountain road but due to the position of antennas, the base station also covers part of the ground areas.
  • the road is exposed to radio signals from many other base stations so only very few frequencies are clean enough to be assigned to the base station A. It is necessary to prevent traffic from ground level being captured by the base station A otherwise it will run into congestion.
  • the signals from selected remotely located base stations B and C are used as references.
  • the mobile telephone On the mountain, the mobile telephone is in line of sight with base stations B and C so their downlink signal strengths relative to that of the serving base station is high.
  • ground area the situation is reversed as signals from base stations B and C are blocked off by buildings.
  • the mobile telephone is arranged to monitor the signal strength and pass the information to the central controller which will determine the relative location of the mobile telephone and decide in this embodiment whether a handover is actually necessary or not.
  • the signal strength information is dealt with as follows:-
  • L s downlink signal strength of the serving base station
  • L cs1 downlink signal strength of the 1st selected base station
  • L cs2 downlink signal strength of the 2nd selected base station
  • L CSX downlink signal strength of the xth selected base station
  • d.,, d 2 , ... d ⁇ are constants, the values of which are determined from the predicted or measured signal strength of the serving base station and those of selected base stations inside and outside the planned service area.
  • service area control is subject to what can be referred to as "service area control”.
  • a typical logic programme for determining handovers generally is automatically carried out by the central controller as follows:-
  • a radio traffic channel is set up between a mobile telephone and a serving base station.
  • the mobile telephone periodically measures the downlink signal strength of the serving base station and those of other base stations in accordance with the information received from the network. All measurement results are reported to the central controller via the serving base station. Measurement results include: For the serving base station:
  • step (d) If T > 0, handover is necessary, proceed to step (d) . Go back to step (b) otherwise.
  • the central controller selects a number of base stations as potential handover targets by using the respective qualifying function:
  • Q ni is a function parameterized to determine whether the base station identified by C nj is qualified as a handover target. If Q n . > o, the base station is qualified. (e) The central controller determines the priority of qualified handover targets by using the priority function:
  • the central controller commands the mobile to handover to the target base station having the highest priority.
  • the central controller is programmed to operate as follows:
  • L js1 downlink signal strength of the 1st potential interferer of the serving base station.
  • L is2 downlink signal strength of the 2nd potential interferer of the serving base station.
  • L ⁇ sm downlink signal strength of the mth potential interferer of the serving base station
  • the C/I ratio for the serving base station can then be calculated:
  • T > 0 means that the C/I radio is worse than the minimum acceptable level so handover to another better base station is necessary.
  • the associated potential interferers are picked out from the k non-serving base stations in the measurement reports.
  • L. ⁇ ! downlink signal strength of the 1st potential interferer of base station identified by C ..
  • L in ' 2 downlink signal strength of the 2nd potential interferer of base station identified by C ⁇ .
  • L jnjm downlink signal strength of the mth potential interferer of base station identified by C ..
  • Q > 0 means the C/I radio is better than the minimum acceptable level so the base station is qualified to be a handover target.
  • a priority function of the base station identified by C nj . is defined as :
  • the priority of potential handover targets is determined solely on the corresponding C/I ratio. The better the C/I ratio and hence the signal quality, the higher the priority.
  • L ps1 downlink signal strength of the 1st reference base station for estimating the C/I ratio of the serving base station
  • L rs2 downlink signal strength of the 2nd reference base station for estimating the C/I ratio of the serving base station
  • L rs ⁇ downlink signal strength of the xth reference base station for estimating the C/I ratio of the serving base station
  • CI, L d / MAX [(L rsl * a $1 ) f (L ps2 * a s2 ) (L ps ⁇ * a, ⁇ ) ]
  • the triggering function T for handover is defined as:
  • T Ci_threshold - CIs where ci_threshold is pre-defined minimum acceptable C/I ratio.
  • T > 0 means that the C/I radio is worse than the minimum acceptable level so handover to another better base station is necessary.
  • the potential handover target is identified by C .. This is picked out from the associated reference base stations from the k non-serving base stations in the measurement reports.
  • L rnJ1 downlink signal strength of the 1st reference base station for estimating the C/I ratio of the base station identified by C.
  • L rnj2 downlink signal strength of the 2nd reference base station for estimating the C/I ratio of the base station identified by C,
  • L rnj ⁇ downlink signal strength of the xth reference base station for estimating the C/I ratio of the base station identified by Cnj
  • the C/I ratio for the base station identified by C n . can then be calculated:
  • the associated qualifying function is defined as:
  • Q > 0 means that the C/I ratio is better than the minimum acceptable level so the base station is qualified to be an handover target. In other words, provided the C/I ratio for the potential handover target station is above a predetermined value a handover can be carried out.
  • the priority of potential handover targets is determined solely on the corresponding C/I ratio. The better the C/I ratio and hence the signal quality, the higher the priority.
  • L csl downlink signal strength of the 1st selected base station for estimating whether the mobile is within the planned service area of the in-use base station.
  • L cs2 downlink signal strength of the 2nd selected base station for estimating whether the mobile is within the planned service area of the in-use base station.
  • CSX downlink signal strength of the xth selected base station for estimating whether the mobile is within the planned service area of the in-use base station.
  • the triggering function T > 0 or handover function is provided if:
  • T > 0 means that the mobile is outside the planned service area of the in-use base station so handover to another base station is necessary.
  • the potential handover target is identified by C nj , the associated reference base stations are chosen from the k non-serving base stations in the measurement reports.
  • L cnj ⁇ downlink signal strength of the xth selected base station for estimating if the mobile is within the planned service area of the base station identified by -* Cnnj.i.
  • the qualifying function Q is greater than 0 if:
  • Q > 0 means that the mobile is with the planned service area of the base station identified by cnj SO It IS qualified as an handover target.
  • the described handover arrangements can be applied to underlay-overlay cellular networks.
  • the cellular network has an underlay-overlay configuration v/here some of the cells have super re-used carrier frequencies.
  • the operating spectrum of the network is divided into two groups, namely a regular-reuse group and a super-reuse group.
  • the regular-reuse frequencies are reused over safe distance such as that in 7-cell reuse pattern and are intended to serve mobile telephones near the cell boundary where the C/I ratio is usually the worst.
  • the super-reuse frequencies are reused very intensively to produce a required increased capacity.
  • Super-reuse frequencies allocated to a base station are divided into several groups with each group having different sources of interference. Based on the profile of interference to which each mobile telephone is exposed to, the central controller determines the most appropriate frequency group to be assigned for carrying traffic.
  • Stand-alone micro cells with antenna height well below the roof level may be equipped solely with super-reuse frequencies.
  • a micro cell at good location can effectively absorb the traffic of more than one ordinary base stations in its vicinity.
  • the surrounding base stations are usually referred to as "parent base stations” and the micro cell is referred to as "child base stations".
  • - 24 The conventional frequency selection mechanism used with underlay-overlay configuration is only based on the signal strength of the serving base station. A strong signal means that the mobile is close to the base station and the system will assign a super-reuse frequency for a call. Otherwise, a regular-reuse frequency will be used.
  • the arrangement works well over flat, homogeneous terrains but in interference limited environment, signal strength alone is no indication in practice of the susceptibility to interference. In open areas, the signal level is usually high but so is the chance of interference. When the signal is weak, the mobile telephone may be inside buildings and well shielded from interference.
  • a frequency selection mechanism using embodiments of the invention is therefore more effective.
  • the improved handover arrangements of the present invention may be applied to selection of frequencies. The procedures are as follows:
  • the central controller checks if sufficiently clean super-reuse frequencies are available (including those in associated child base stations) by using qualifying functions based on:
  • the central controller prioritizes the usable super-reuse frequencies according to the respective number of idle traffic channels. The more the number of idle traffic channels, the higher the priority.
  • the central controller On super-reuse frequencies, the central controller constantly monitors the in-use radio links to see if it is necessary to return to regular-reuse frequencies. Handover triggering functions based on the following criteria can be used:
  • the central controller evaluates every regular-reuse frequency of the serving base stations and those in its neighbourhood by using qualifying functions and prioritizing functions based on :
  • step (h) Go back to step (b) .
  • downlink signal strengths of control signals are measured and used to determine the handover criteria and in Figure 4 the location of the mobile telephone. It will be appreciated that downlink signal strengths of the traffic channels might also be employed additionally or alternatively.
  • the handover criteria is determined on the basis of C/I ratios and when this ratio falls below a predetermined value for a serving base station, or otherwise, C/I ratios of potential handover target base stations are monitored to identify and choose an appropriate of those stations for handover. 26a
  • a l tier of co-control channel base stations B l tier of co-traffic channel base stations C l' tier of co-control channel and co-traffic channel base stations

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Selon l'invention, un réseau téléphonique cellulaire numérique est pourvu de systèmes de transfert intercellulaire pour téléphone mobile, dans lequel un téléphone mobile fournit des signaux relatifs aux intensités des signaux de liaisons descendantes. Ces signaux sont les signaux provenant d'une première station de base, station avec laquelle le téléphone est en communication, ainsi que des signaux de liaisons descendantes provenant d'autres stations de base sélectionnées du réseau. Sur la base de ces informations, un contrôleur central calcule un rapport porteuse/brouillage et détermine quand et à quelle autre station de base la communication du téléphone mobile doit être transférée.
PCT/GB1996/001280 1995-05-30 1996-05-30 Systemes de transfert intercellulaire pour reseaux telephoniques cellulaires numeriques WO1996038997A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU58290/96A AU701840B2 (en) 1995-05-30 1996-05-30 Mobile assisted handover arrangements for digital cellular telephone networks
EP96919926A EP0829179A1 (fr) 1995-05-30 1996-05-30 Systemes de transfert intercellulaire pour reseaux telephoniques cellulaires numeriques

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9510861.9 1995-05-30
GBGB9510861.9A GB9510861D0 (en) 1995-05-30 1995-05-30 Handover arrangements for digital cellular telephone networks

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WO1996038997A1 true WO1996038997A1 (fr) 1996-12-05
WO1996038997B1 WO1996038997B1 (fr) 1997-01-23

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EP (1) EP0829179A1 (fr)
CN (1) CN1085031C (fr)
AU (1) AU701840B2 (fr)
GB (1) GB9510861D0 (fr)
WO (1) WO1996038997A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
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WO1998030043A2 (fr) * 1996-12-31 1998-07-09 Telefonaktiebolaget Lm Ericsson (Publ) Compensation des inexactitudes de mesure de transfert intercellulaire assiste par unite mobile
WO1998037719A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
WO1998037720A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
FR2768586A1 (fr) * 1997-09-12 1999-03-19 Nortel Matra Cellular Estimation previsionnelle du rapport signal a interferences dans un reseau cellulaire de radiocommunications
FR2768584A1 (fr) * 1997-09-12 1999-03-19 Nortel Matra Cellular Dispositif d'allocations de ressources dans un reseau de radiocommunications
WO2000051389A1 (fr) * 1999-02-26 2000-08-31 Telefonaktiebolaget Lm Ericsson (Publ) Preservation des limites cellulaires lors d'un transfert dans un systeme cellulaire d'antenne intelligent
WO2001011908A1 (fr) * 1999-08-10 2001-02-15 Motorola Inc. Procede permettant de reduire les interferences entre des mobiles utilisant des modes duplex differents
GB2362297A (en) * 2000-01-07 2001-11-14 Motorola Inc Location based consideration for cellular telephone handoff
US6363252B1 (en) 1997-09-17 2002-03-26 Nokia Mobile Phones Ltd. Advanced method for executing handover
WO2003017544A1 (fr) * 2001-08-16 2003-02-27 Interdigital Technology Corporation Procede de duplexage par repartition dans le temps destine a determiner si un transfert doit etre lance ou non
US7142860B2 (en) 2001-03-30 2006-11-28 Telefonaktiebolaget Lm Ericsson (Publ) Network/cell/interface selection in mixed networks
EP1843612A2 (fr) 2006-04-07 2007-10-10 NTT DoCoMo, Inc. Appareil de mesure et procédé de mesure de la qualité d'une zone

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CN102083159A (zh) * 2009-11-30 2011-06-01 中国移动通信集团北京有限公司 一种移动通信系统中的切换控制方法及无线网络控制器

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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5970407A (en) * 1996-12-31 1999-10-19 Telefonaktiebolaget L M Ericsson (Publ) Compensation for mobile assisted handoff measurement inaccuracies
WO1998030043A3 (fr) * 1996-12-31 1998-10-29 Ericsson Telefon Ab L M Compensation des inexactitudes de mesure de transfert intercellulaire assiste par unite mobile
WO1998030043A2 (fr) * 1996-12-31 1998-07-09 Telefonaktiebolaget Lm Ericsson (Publ) Compensation des inexactitudes de mesure de transfert intercellulaire assiste par unite mobile
WO1998037719A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
WO1998037720A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
US6493554B1 (en) 1997-02-18 2002-12-10 Nokia Telecommunications Oy Handover in a mobile communication system
US6219550B1 (en) 1997-02-18 2001-04-17 Nokia Telecommunications Oy Handover in a mobile communication system with adjustable error correction
WO1999014964A1 (fr) * 1997-09-12 1999-03-25 Nortel Matra Cellular Dispositif d'allocation de ressources dans un reseau de radiocommunications
FR2768586A1 (fr) * 1997-09-12 1999-03-19 Nortel Matra Cellular Estimation previsionnelle du rapport signal a interferences dans un reseau cellulaire de radiocommunications
WO1999014968A1 (fr) * 1997-09-12 1999-03-25 Nortel Matra Cellular Estimation previsionnelle du rapport signal a interferences dans un reseau cellulaire de radiocommunications
FR2768584A1 (fr) * 1997-09-12 1999-03-19 Nortel Matra Cellular Dispositif d'allocations de ressources dans un reseau de radiocommunications
US6363252B1 (en) 1997-09-17 2002-03-26 Nokia Mobile Phones Ltd. Advanced method for executing handover
US6259918B1 (en) 1999-02-26 2001-07-10 Telefonaktiebolaget Lm (Publ) Preservation of cell borders at hand-off within a smart antenna cellular system
WO2000051389A1 (fr) * 1999-02-26 2000-08-31 Telefonaktiebolaget Lm Ericsson (Publ) Preservation des limites cellulaires lors d'un transfert dans un systeme cellulaire d'antenne intelligent
WO2001011908A1 (fr) * 1999-08-10 2001-02-15 Motorola Inc. Procede permettant de reduire les interferences entre des mobiles utilisant des modes duplex differents
EP1077582A1 (fr) * 1999-08-10 2001-02-21 Motorola, Inc. Méthode pour réduire l'interférence entre mobiles qui utilisent une technique duplex différente
GB2362297B (en) * 2000-01-07 2003-10-15 Motorola Inc Method and apparatus for location based consideration for cellular telephone handoff
GB2362297A (en) * 2000-01-07 2001-11-14 Motorola Inc Location based consideration for cellular telephone handoff
US7142860B2 (en) 2001-03-30 2006-11-28 Telefonaktiebolaget Lm Ericsson (Publ) Network/cell/interface selection in mixed networks
US7068626B2 (en) * 2001-08-16 2006-06-27 Interdigital Technology Corporation Method of using a mobile unit to autonomously determine a serving cell
WO2003017544A1 (fr) * 2001-08-16 2003-02-27 Interdigital Technology Corporation Procede de duplexage par repartition dans le temps destine a determiner si un transfert doit etre lance ou non
US7680080B2 (en) 2001-08-16 2010-03-16 Interdigital Technology Corporation Method of using a mobile unit to determine whether to commence handover
EP1843612A2 (fr) 2006-04-07 2007-10-10 NTT DoCoMo, Inc. Appareil de mesure et procédé de mesure de la qualité d'une zone
JP2007281967A (ja) * 2006-04-07 2007-10-25 Ntt Docomo Inc 測定装置及びエリア品質測定方法
EP1843612A3 (fr) * 2006-04-07 2009-01-14 NTT DoCoMo, Inc. Appareil de mesure et procédé de mesure de la qualité d'une zone
US8055202B2 (en) 2006-04-07 2011-11-08 Ntt Docomo, Inc. Measuring apparatus and area quality measuring method

Also Published As

Publication number Publication date
CN1085031C (zh) 2002-05-15
CN1191660A (zh) 1998-08-26
AU701840B2 (en) 1999-02-04
GB9510861D0 (en) 1995-07-26
EP0829179A1 (fr) 1998-03-18
AU5829096A (en) 1996-12-18

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