WO1992002104A1 - Systeme de radio cellulaire - Google Patents

Systeme de radio cellulaire Download PDF

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Publication number
WO1992002104A1
WO1992002104A1 PCT/GB1991/001240 GB9101240W WO9202104A1 WO 1992002104 A1 WO1992002104 A1 WO 1992002104A1 GB 9101240 W GB9101240 W GB 9101240W WO 9202104 A1 WO9202104 A1 WO 9202104A1
Authority
WO
WIPO (PCT)
Prior art keywords
mobile station
base station
microcell
handover
coverage area
Prior art date
Application number
PCT/GB1991/001240
Other languages
English (en)
Inventor
Si Tak Stanley Chia
Original Assignee
British Telecommunications Public Limited Company
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 British Telecommunications Public Limited Company filed Critical British Telecommunications Public Limited Company
Publication of WO1992002104A1 publication Critical patent/WO1992002104A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/04—Reselecting a cell layer in multi-layered cells

Definitions

  • the present invention relates to cellular radio, and in particular, although not exclusively, to a cellular radio system having overlapping acrocells and microcells.
  • a conventional cellular radio system has a number of radio base stations each serving a respective radio coverage area or cell, with which a mobile radio station can communicate over a radio link.
  • the communication link is transferred from the present base station to the next base station using a procedure known as hand-over or hand-off.
  • the need for hand-over is usually determined on the basis of one or more criteria. Commonly used criteria are received signal strength indication (RSSI) of the mobile at the base station, and the distance from the current base station as determined by the round trip time for signals to and from the mobile station.
  • RSSI received signal strength indication
  • BER bit error rate
  • a base station monitors the RSSI of the mobile station as the mobile station travels through a cell and when the RSSI falls below a certain threshold, hand-over of the radio link from the present base station to another base station with which the mobile station can have an improved radio link takes place.
  • the cells of conventional cellular radio systems are relatively large, typically several kilometres across, and this allows time for data to be averaged for even a fast moving mobile station and a handover decision made on the basis of trends in that data.
  • Microcellular radio systems with relatively small cells of up to a few kilometres in diameter, and typically less than one kilometre in diameter, and these are often referred to as "microcells" while the relatively large, sometimes called wide area or conventional cells are often referred to as “macrocells”. These terms do not indicate absolute size limitations but rather reflect the relative size of these two cell types. Microcellular radio systems should provide a better frequency re-use and hence greater user density. Proposals for microcellular systems suggest their application to road networks, for example motorways where high speed mobile stations will pass through a microcell very quickly, or to pedestrian precincts or in-building environments where there many be a high density of mobile stations. This means that the time for acquisition, let alone averaging of data, e. g. RSSI, for hand-over is limited. Furthermore, the radio coverage of microcells is subject to large variations in signal level over relatively short distances, in for example in an urban environment.
  • microcells might well only provide duplicate coverage over a small part of a macrocell.
  • macro-macrocell handover between adjacent macrocells macrocell to microcell handover when a mobile station enters a microcell coverage area within a macrocell
  • micro-microcell handover between adj cent microcells microcell to macrocell handover when a mobile station leaves a microcell coverage area.
  • microcell to macrocell handover when a mobile station leaves a microcell coverage area.
  • a microcell can have quite abrupt boundary coverage compared to the relatively flexible boundary coverage of macrocells.
  • the present invention relates to the provision of other criteria for handover, particularly, though not exclusively, in microcellular systems.
  • the invention provides a cellular radio system for providing communication with a mobile station, comprising: first and second base stations, each for providing communication with the mobile station over respective first and second radio coverage areas; a plurality of identification transmitters within the first radio coverage area, each for transmitting an identification signal receivable by the mobile station within a separate identified coverage area; control means for monitoring progress of a mobile station through the first radio coverage area by assessing a sequence of at least two received identification signals, to determine any requirement for handover of communication with the mobile station from the first base station to the second base station.
  • a cell served by a base station is defined as the area over which radio communications with a mobile is intended or expected to be maintained, i. e. the area beyond which handover will be required.
  • a cell boundary may coincide, in the limiting case, with the respective radio coverage area of a base station, but may, and probably usually will be within that radio coverage area.
  • the cellular radio system of the present invention can use the determined position of the mobile station as an indication of an immediate requirement for handover or as an indication of the impending requirement for handover, depending on the positioning of the location identifying transmitters relative to the cell boundary.
  • the location identifying transmitters could for example be positioned at locations within the cell so that passage of a mobile station through a cell could be tracked, so that the need for handover can be anticipated.
  • the location identifying transmitters may be located so that receipt of the identification signal is indicative of the entry or exit of a mobile .station into or from a particular base station radio coverage area.
  • a location identifying transmitter could be placed adjacent to or just at the intended limit of the cell, i. e. the cell boundary, to provide an indication of the imminent entry or exit, of a mobile station to or from that cell.
  • the location identifying transmitters may be located so that receipt of the identification signal is indicative of a mobile station having entered a base station coverage area.
  • the identifiers can each have a unique identification code or some location identifying transmitters may share a common identification code. In the latter case receipt of the identification signal may be taken to indicate a particular type of impending occurrence, for example a particular type of impending handover, e. g. microcell to macrocell handover.
  • the common identification signals can be divided into categories, for example
  • Figure 1 shows a cellular radio system with a number of overlapping macrocells and microcells overlaid on a road network
  • FIG. 2 shows the location of a microcell identifier (MI) with respect to a mobile station, with inset construction of a MI in block schematic form;
  • Figure 3 shows a MI located at an entry or exit point of a microcellular network i. e. a primary node;
  • Figure 4 shows a minor road crossing a microcell and has two examples of each of a secondary and an intermediate node
  • Figure 5 shows a boundary network of two microcells
  • Figure 6 is a simplified flow schematic for the MI controlled handover from a macrocell to a microcell
  • Figure 7 and Figure 8 show typical arrangements of microcells at major road junctions
  • Figure 9 is a simplified flow schematic for the MI controlled handover from a microcell to a macrocell
  • Figure 10 shows the arrangement of MI' s used in a queued handover system
  • Figure 11 is a flow schematic for queued MI controlled handover from macrocell to microcell
  • Figure 12 shows a typical microcellular network infrastructure
  • FIG. 1 shows a cellular radio system comprising a plurality of base stations (BS) (1,5) each having a radio transceiver for providing radio communication coverage over a respective radio coverage area (2, 3), which area may constitute a macrocell (2) or a microcell (3). These macrocells and microcells are overlaid on a road network (4).
  • identification transmitters or Microcell Identifiers (Mis) (8 - marked by an asterisk) are provided for repeatedly transmitting an identification signal over an identified radio coverage area (10) which is at least partially within one of the said radio coverage areas (2) or (3).
  • a radio Ml comprises a power supply (13) for powering the unit, a ROM (14), a modulator (15), a CPU (14a), RF driver (16a), and an antenna (16).
  • the ROM (14) is used to store a particular code sequence for the MI which is read by the modulator (15), and passed to the RF section (16a) which drives the antenna (16) to transmit this code sequence.
  • the antenna (16) is a unity gain omni-directional monopole antenna.
  • a typical radio MI is mounted at a height of 6m, for example from a lamp-post (11), and would have a transmitter power of approximately 4.8 x 10 '12 , to provide, assuming a MS antenna (12) at a height of 1.5m, a receiving threshold for the MS of -120 dBm and an inverse 4 th power propagation law, a typical MI coverage distance of approximately 50m.
  • a MI coverage area of 50m will give a mobile unit 2.8 seconds to detect the broadcast.
  • the coverage area of the Mis can be extended by increasing the transmitter power according to the local vehicular traffic speed or geographical requirements.
  • Microcells have very well defined boundaries and the flow of mobile stations within a microcell is generally not random, consequently a finite number of entry and exit points of a MS from or to a microcell can be identified. Specifically the position within the microcell of a MS when control of its communication link with a BS needs to be handed over for example from one microcell to another, from a microcell to a macrocell or vice versa needs to be identified.
  • Primary nodes (17) are the points at which a MS will enter or exit the trailing (first or last) microcell of a microcellular network. There may be more than two primary nodes per microcellular network, if for example the network includes complex road junctions.
  • secondary nodes (18) points within the microcell, other than primary nodes (17), at which a MS may enter or leave the microcellular network for example side roads (21) are called secondary nodes (18).
  • Intermediate MS' s (19) are positioned along the length of the microcell and particularly either side of secondary nodes.
  • Boundary nodes (20) occur at the intersection (22) of two microcells, as shown in figure 5.
  • MI stores in ROM (14) one of 4 possible code sequences dependant on its position.
  • MI' s at primary nodes transmit entry/exit code sequences which are unique, within the macrocell, to each primary node.
  • Intermediate code sequences transmitted by intermediate MS' s are the same for all intermediate MI' s within the same microcell but are unique to each microcell within the macrocell.
  • Mis at secondary nodes transmit an exit code which is common to all microcells within the macrocell.
  • the fourth type of code sequence is transmitted by a MI at a boundary node. These codes are unique, within the microcell to each boundary node.
  • MS' s will continuously monitor transmissions from MI' s and will retransmit a version of the received code sequence to the BS' s which will take the appropriate handover (HO) decision.
  • a MS enters a microcell via a secondary node (see figure 4) it will, on passing the secondary node (18), receive an exit code sequence, however no action will be taken and HO will not occur unless the MS subsequently receives an intermediate code sequence at an intermediate node (19).
  • the MS simply crosses the microcell it will remain under the control of the Macrocell BS, whereas if it enters and progresses along the microcell it will be handed over to the microcell BS.
  • Intermediate Mis also serve to initiate HO from the macrocell to the microcell BS of a MS which switches on only when it is well within the microcell.
  • a microcell In passing from one microcell to another a MS (24), in figure 5, will pass a boundary MI (20) from which it will receive a boundary code sequence.
  • a microcell may have more than two boundary nodes as shown in figures 7 and 8.
  • microcell there are two possible exit points from a microcell to a macrocell, via a primary node or via a secondary node. If a MS is currently in a microcell the detection of a primary node code sequence will be identified by the microcell BS as signifying an exit to a macrocell, and the microcell BS will request HO to the macrocell BS in the way shown schematically in figure 9.
  • a cellular radio system comprising a queued MI controlled HO process.
  • This system is substantially as previously described, except that at primary, secondary and boundary nodes, two, rather than one, Mis are provided separated by a small physical distance typically 1 to 20m as shown in figure 10.
  • the position of the first MI (25) or (26) encountered gives the point within the microcell at which the HO process is to be started.
  • the position of the second MI (26) or (25) encountered marks the absolute limit of the microcell.
  • a handover request will be initiated. If no channel is immediately available, the base station will continue to attempt the handover until the second MI (26) is encountered where a forced termination of the call or an emergency handover to a macrocell base station will be effected.
  • a flow diagram for this process is shown in Figure 11. If the MS is still travelling along a microcellular cluster, the macrocell base station will attempt to re-direct the call back to the next available microcell base station when the MS encounters an intermediate MI in that microcell.
  • Radio transmitters but could alternatively be infra-red or ultra-sound transmitters or induction loops or piezo-electric transducers, the latter two conveniently being buried beneath the road surface.
  • MI' s can usefully be used in pedestrian precincts or in buildings. They are particularly useful for indoor microcell environments as these environments have very well defined exits and entrances to specific areas. For instance, a building will have a well defined entrance to the lobby. From the lobby, there will be a defined entrance to lifts and corridors. Rooms along the corridors have doors at their entrances.
  • Microcell identifiers may be installed at all doorways or entrances where handovers are desired. As mobile units are moving at slow speed, the criterion of fast handover initiation may not be as critical as in an outdoor area. Furthermore, there will be sufficient time for the mobile unit to listen to the broadcast of the microcell identifiers. Shielding from obstacles will not be a problem as the microcell identifiers could be installed overhead or at prominent positions along the side of a corridor.
  • clusters of macrocell base stations (1) are under the control of a mobile switching centre (27) which is connected to the public switched telephone network (PSTN).
  • clusters of microcell BSs (5) can also be linked together by a microcell control unit (28).
  • the distribution of these microcell control units may be as few as one per macrocell, as presented in Figure 13. Calls originated from a microcell base station (5) will be routed through a microcell control unit (28) to the PSTN directly without involving a mobile switching centre (27). This will reduce the loading of a mobile switching centre and its associated communication network.
  • a mobile control unit should have the same function as a mobile switching centre (27) except that the former serves* microcells (3) while the latter serves macrocells (2).
  • the boundary of the last microcell within an overlaying macrocell should coincide with the boundary of that macrocell.
  • the file for the MS is usually kept within the mobile switching centre and the macrocell base station.
  • the file for the MS is still initially kept within the mobile switching centre and the macrocell base station. A copy of the file is also sent to the microcell control unit. As the MS enters a microcell, the MS will be de-registered from the mobile switching centre and re-registered with the microcell base station.
  • Registration information is, however, retained by the macrocell BS until the MS proceeds to a microcell located beyond the current macrocell.
  • the file of the MS will be routed through to the next microcell base station via the links between the two microcell control units.
  • the file for this MS which is kept within the current macrocell base station will also be transferred to the new macrocell base station.
  • the transmission of the code sequence could be organised on a signalling channel using frequency division multiple access (FDMA) mode.
  • FDMA frequency division multiple access
  • the carrier carrying the code sequence should be continuously transmitted without interruption in order to guarantee the reception of the broadcast by the MS.
  • the modulation can be simple non-coherent frequency shift keying, for example.
  • the invention may be used within a digital cellular system operating with time division multiple access (TDMA) such as the Group Special Mobile (GSM) system.
  • TDMA time division multiple access
  • GSM Group Special Mobile
  • the code sequence broadcast by MI' s could conveniently be, for example, 8 bit long digital code words.
  • the MS could monitor for MI broadcasts during a currently idle time slot within the TDMA time frame, for example between transmit and receive time slots.
  • the information can be conveyed back to the serving BS via the Slow Associated Control Channel.
  • the receiver within the MS must be programmed to tune to a MI Broadcast Channel after tuning to the Broadcast Control Channel carrier.
  • microcell identifiers are well suited for TDMA digital cellular radio systems, they may also be used in analogue cellular radio systems (e. g. TACS).
  • TACS analogue cellular radio systems
  • a simple approach is to implement a second simple receiver (microcell identifier receiver) incorporated into the existing mobile unit.
  • the front end can be shared with the existing transceiver unit.
  • decoding logic in the microcell identifier receiver With suitable decoding logic in the microcell identifier receiver, the necessity of handover can be signalled back to the base station via in-band supervisory signalling which is required for maintaining the communication link.
  • the signalling protocol within the base station has to be modified to interpret the information returned by the mobile unit.
  • An alternative approach is to force the mobile unit to periodically switch over to the specific frequency to listen to the microcell identifier broadcast. Interruption of conversation may be necessary but this will only be a few milliseconds and will not cause any perceivable impairment to the speech. During this period, the frequency synthesizer re-tunes to a specific channel for the microcell identifier broadcast, decodes the message, and then re-tunes back to the original channel. If a handover message is detected, the information can be transferred back to the base station via in-band signalling. Similar modification of the signalling protocol is also necessary.

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

Abstract

L'invention décrit un système de radio cellulaire dans lequel une pluralité de stations de base (1, 5) possédant chacune un émetteur-récepteur radio opèrent une couverture radio sur une zone respective de couverture horizontale. Des émetteurs d'identification (8) transmettent, de façon répétée, un signal d'identification sur une zone de couverture radio identifiée (10) qui se trouve au moins partiellement à l'intérieur de l'une desdites zones de couverture horizontales, pour qu'une station mobile (6) possédant un émetteur-récepteur radio puisse communiquer avec l'une des stations de base. A réception du signal d'identification, on peut déterminer si la station mobile se trouve à l'intérieur de ladite couverture radio identifiée de l'émetteur d'identification.
PCT/GB1991/001240 1990-07-25 1991-07-25 Systeme de radio cellulaire WO1992002104A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB909016331A GB9016331D0 (en) 1990-07-25 1990-07-25 Cellular radio
GB9016331.2 1990-07-25

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WO1992002104A1 true WO1992002104A1 (fr) 1992-02-06

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GB (1) GB9016331D0 (fr)
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Cited By (23)

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Publication number Priority date Publication date Assignee Title
EP0562743A1 (fr) * 1992-03-23 1993-09-29 AT&T Corp. Méthode et dispositif pour augmenter la capacité des participants dans un réseau à macro-/micro-cellule
EP0582344A1 (fr) * 1992-08-04 1994-02-09 Philips Patentverwaltung GmbH Système radio mobile cellulaire avec cellules partiales
EP0615392A1 (fr) * 1993-03-11 1994-09-14 DETECON DEUTSCHE TELEPOST CONSULTING GmbH Méthode et appareil pour le transfert d'appel dans un réseau radio mobile dépendant de la localisation
WO1995025410A1 (fr) * 1994-03-16 1995-09-21 Detemobil Deutsche Telekom Mobilnet Gmbh Procede de localisation de stations mobiles
WO1995035006A1 (fr) * 1994-06-14 1995-12-21 Nokia Telecommunications Oy Commutations dans un systeme mobile de telecommunications
EP0692920A1 (fr) * 1994-07-13 1996-01-17 France Telecom Sélection de cellule dans un réseau radiotéléphonique cellulaire multicouche
US5521961A (en) * 1993-03-26 1996-05-28 Celcore, Inc. Mobility management method for delivering calls in a microcellular network
GB2295943A (en) * 1994-12-09 1996-06-12 Motorola Inc Method for determining handover in a communications system
WO1996019087A1 (fr) * 1994-12-15 1996-06-20 Nokia Telecommunications Oy Systeme de station mobile cellulaire
US5627881A (en) * 1993-03-26 1997-05-06 Celcore, Inc. Off-load-cellular system for off-loading cellular service from a main cellular system to increase cellular service capacity
WO1997026770A2 (fr) * 1996-01-16 1997-07-24 Telefonaktiebolaget Lm Ericsson (Publ) Systeme et procede de collecte adaptative de mesures et mise en file d'attente de transfert dans un reseau de telecommunications radio
WO1998014019A1 (fr) * 1996-09-24 1998-04-02 Robert Bosch Gmbh Methode de transmission sans fil d'informations locales ou utilitaires, et installation d'emission/reception
WO1998035524A2 (fr) * 1997-02-11 1998-08-13 Ericsson Inc. Procede et systeme pour localiser une station mobile dans un reseau de telecommunication mobile
WO1998046031A2 (fr) * 1997-04-04 1998-10-15 Northern Telecom Limited Procede et dispositif permettant de commander l'affectation de voies de trafic dans des reseaux de telecommunications a macrocellules/microcellules
EP0690650A3 (fr) * 1994-06-29 1999-03-17 AT&T Corp. Système de réservation de canal dépendant du trafic pour transferts dans les réseaux cellulaires
CN1054489C (zh) * 1992-06-30 2000-07-12 摩托罗拉公司 双模式通信网络
EP1077579A1 (fr) * 1999-08-19 2001-02-21 Texas Instruments Incorporated Ameliorations dans des systèmes mobiles cellulaires
EP1241909A1 (fr) * 2001-03-13 2002-09-18 TELEFONAKTIEBOLAGET L M ERICSSON (publ) Procede et support lisible par ordinateur pour le logiciel de determination de l'emplacement d'un terminal mobile
WO2002073987A2 (fr) * 2001-03-13 2002-09-19 Telefonaktiebolaget L M Ericsson (Publ) Procede et support lisible par un ordinateur destines a un programme de localisation d'emplacement d'un terminal mobile
EP1429570A1 (fr) * 2002-12-13 2004-06-16 Abb Research Ltd. Système et procédé de localisation sur site
WO2005039215A1 (fr) 2003-10-20 2005-04-28 Telefonaktiebolaget Lm Ericsson Reseau radiocellulaire virtuel
WO2007103062A1 (fr) 2006-03-09 2007-09-13 Lucent Technologies Inc. Transferts de communication sans fil à l'intérieur d'une macrocellule
US7539161B2 (en) 2003-10-20 2009-05-26 Telefonaktiebolaget Lm Ericsson (Publ) Virtual cell network

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Cited By (51)

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Publication number Priority date Publication date Assignee Title
EP0562743A1 (fr) * 1992-03-23 1993-09-29 AT&T Corp. Méthode et dispositif pour augmenter la capacité des participants dans un réseau à macro-/micro-cellule
CN1054489C (zh) * 1992-06-30 2000-07-12 摩托罗拉公司 双模式通信网络
EP0582344A1 (fr) * 1992-08-04 1994-02-09 Philips Patentverwaltung GmbH Système radio mobile cellulaire avec cellules partiales
AU670954B2 (en) * 1992-08-04 1996-08-08 Koninklijke Philips Electronics N.V. Cellular mobile radio system comprising sub-cells
EP0615392A1 (fr) * 1993-03-11 1994-09-14 DETECON DEUTSCHE TELEPOST CONSULTING GmbH Méthode et appareil pour le transfert d'appel dans un réseau radio mobile dépendant de la localisation
US5862483A (en) * 1993-03-26 1999-01-19 Dsc/Celcore Inc. Mobility management method for delivering calls in a microcellular network
US5627881A (en) * 1993-03-26 1997-05-06 Celcore, Inc. Off-load-cellular system for off-loading cellular service from a main cellular system to increase cellular service capacity
US5521961A (en) * 1993-03-26 1996-05-28 Celcore, Inc. Mobility management method for delivering calls in a microcellular network
US5933114A (en) * 1994-03-16 1999-08-03 Detemobil Deutsche Telekom Mobilnet Gmbh Process and apparatus for locating mobile stations
WO1995025410A1 (fr) * 1994-03-16 1995-09-21 Detemobil Deutsche Telekom Mobilnet Gmbh Procede de localisation de stations mobiles
WO1995035006A1 (fr) * 1994-06-14 1995-12-21 Nokia Telecommunications Oy Commutations dans un systeme mobile de telecommunications
CN1081883C (zh) * 1994-06-14 2002-03-27 诺基亚电信公司 移动通信系统及越区切换方法
AU695182B2 (en) * 1994-06-14 1998-08-06 Nokia Telecommunications Oy Handover in a mobile communication system
US5884176A (en) * 1994-06-14 1999-03-16 Nokia Telecommunications Oy Fast handover by preassigning neighboring candidate cells
EP0690650A3 (fr) * 1994-06-29 1999-03-17 AT&T Corp. Système de réservation de canal dépendant du trafic pour transferts dans les réseaux cellulaires
FR2722628A1 (fr) * 1994-07-13 1996-01-19 Tabbane Sami Selection de cellule dans un reseau radiotelephonique cellulaire multicouche
EP0692920A1 (fr) * 1994-07-13 1996-01-17 France Telecom Sélection de cellule dans un réseau radiotéléphonique cellulaire multicouche
GB2295943B (en) * 1994-12-09 1999-07-14 Motorola Inc Method for determining handover in a communications system
WO1996018276A1 (fr) * 1994-12-09 1996-06-13 Motorola Inc. Procede de determination d'un transfert dans un systeme de telecommunications
GB2295943A (en) * 1994-12-09 1996-06-12 Motorola Inc Method for determining handover in a communications system
AU699830B2 (en) * 1994-12-15 1998-12-17 Nokia Telecommunications Oy Cellular mobile station system
US5913169A (en) * 1994-12-15 1999-06-15 Nokia Telecommunications Oy Cellular mobile station system
WO1996019087A1 (fr) * 1994-12-15 1996-06-20 Nokia Telecommunications Oy Systeme de station mobile cellulaire
EP1437911A3 (fr) * 1996-01-16 2004-08-25 Telefonaktiebolaget LM Ericsson (publ) Système et procédé de collecte adaptative de mesures et mise en file d'attente de transert dans un réseau de télécommunications radio
EP1437911A2 (fr) * 1996-01-16 2004-07-14 Telefonaktiebolaget LM Ericsson (publ) Système et procédé de collecte adaptative de mesures et mise en file d'attente de transert dans un réseau de télécommunications radio
WO1997026770A2 (fr) * 1996-01-16 1997-07-24 Telefonaktiebolaget Lm Ericsson (Publ) Systeme et procede de collecte adaptative de mesures et mise en file d'attente de transfert dans un reseau de telecommunications radio
WO1997026770A3 (fr) * 1996-01-16 2001-05-25 Ericsson Telefon Ab L M Systeme et procede de collecte adaptative de mesures et mise en file d'attente de transfert dans un reseau de telecommunications radio
WO1998014019A1 (fr) * 1996-09-24 1998-04-02 Robert Bosch Gmbh Methode de transmission sans fil d'informations locales ou utilitaires, et installation d'emission/reception
WO1998035524A2 (fr) * 1997-02-11 1998-08-13 Ericsson Inc. Procede et systeme pour localiser une station mobile dans un reseau de telecommunication mobile
US6055434A (en) * 1997-02-11 2000-04-25 Ericsson Inc. Method and system for locating a mobile station within a mobile telecommunications network
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