WO1996005708A1 - Systeme et procede de communications destinees a un environnement multicellulaire - Google Patents

Systeme et procede de communications destinees a un environnement multicellulaire Download PDF

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Publication number
WO1996005708A1
WO1996005708A1 PCT/EP1995/003152 EP9503152W WO9605708A1 WO 1996005708 A1 WO1996005708 A1 WO 1996005708A1 EP 9503152 W EP9503152 W EP 9503152W WO 9605708 A1 WO9605708 A1 WO 9605708A1
Authority
WO
WIPO (PCT)
Prior art keywords
underlay
location area
location
microcells
overlay
Prior art date
Application number
PCT/EP1995/003152
Other languages
English (en)
Inventor
Rupinder Singh Oberoi
Paul Crichton
Robert Ivor Davies
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.
Priority to AU33435/95A priority Critical patent/AU3343595A/en
Publication of WO1996005708A1 publication Critical patent/WO1996005708A1/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
    • 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
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H04W36/322—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data by location data
    • 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
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H04W36/324—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data by mobility data, e.g. speed data

Definitions

  • This invention relates in general to a communications system in a multicellular environment, and more particularly to a communications system and a method for determining handover in a multicellular environment including an overlay and underlay of macrocells and microcells.
  • a service coverage area by a base station is called a cell.
  • a larger cell, or macrocell may be further divided into smaller cells, or microcells in order to increase capacity.
  • An overlay of macrocells may be implemented over the same area that an underlay of microcells are implemented.
  • a microcellular network includes a plurality of microcells which may be partially disposed within at least one macrocell.
  • a mobile station may be located in an area that is serviced by both a macrocell and a microcell.
  • system objectives for a. mobile station in idle mode in a microcellular network include during a cell selection process, having mobile stations select a microcell in preference to a macrocell and during subsequent cell re-selection, having fast moving mobile stations camp on to macrocells and slow moving mobile stations stay on the microcellular network.
  • the first objective can be met by modification of path loss criterion parameter Cl as defined in GSM recommendations.
  • a second parameter C2 is defined in the cell selection/reselection algorithm, which enables the phase 2 mobile station to camp on to right type of cell (microcell or macrocell) depending upon the speed of the mobile. This satisfies the second objective.
  • the parameter C2 is only defined as part of GSM phase 2 feature.
  • phase 1 mobiles there are currently a number of microcellular networks which will have a majority of phase 1 mobiles (no phase 2 mobiles are available at present). Therefore, it is essential that a process is defined which will enable current phase 1 mobiles to work efficiently in the microcellular network.
  • phase 1 mobiles there is no method for phase 1 mobiles to differentiate between microcells and macrocells depending upon speed of the mobile.
  • phase 1 mobiles due to existing installed base of phase 1 mobiles, it would be very difficult to of change the mobile software.
  • the software in the infrastructure which will enable slow moving mobiles to remain on microcell and fast moving mobiles to be put on macro cells.
  • a communications system that includes a method in the base stations for determining handovers in a microcellular environment based upon the speed of the mobile station that will handover a fast moving mobile station to a macrocell and a slow moving mobile station to a microcell.
  • a communications system for a multicellular environment having at least one macrocell where partially disposed in the at least one macrocell is a plurality of microcells, each cell having a base station for communications with at least one mobile station, the communications system comprising an overlay location area wherein at least one macrocell is located within the overlay location area and a plurality of underlay location areas at least partially disposed within the overlay location area wherein at least one microcell is located in each underlay location.
  • a method for planning a multicellular environment of at least one macrocell and a plurality of microcells wherein the microcells are at least partially disposed within a macrocell including the steps of assigning a first number of macrocells to an overlay location area and assigning a second number of microcells to an underlay location area.
  • a further embodiment method for determining a handover for a mobile station in a multicellular environment having at least one overlay location area including at least one macrocell and a plurality of underlay location areas each underlay location area having at least one microcell, the underlay location areas are at least partially disposed within the overlay location area, each cell includes a base station, the method comprises the steps of measuring time between messages received at a base station for the mobile station and determining a handover in dependence upon the measured time.
  • FIG. 1 illustrates a multicellular environment according to the present invention.
  • FIG. 2 is a flow chart for a method for preferred embodiment of the present invention.
  • a communications system 20 having a plurality of macrocells 1, 2, 3, 4, 5 where at least partially disposed in at least one macrocell 3 is a plurality of microcells 10, 11, 12, 13, 14.
  • Each macrocell and microcell has a respective base station for communications with at least one mobile station.
  • a fast moving mobile station 17 is shown being serviced by a macrocell 3 and a slow moving mobile station 15 is shown being serviced by a microcell 10.
  • the multicellular communications systems 20 of FIG. 1 further includes an overlay of at least one location area 25 that comprises a number of macrocells 1, 2, 3, 4, 5 that are located within the location area 25 and shown by right to left diagonal shading across macrocells 1, 2, 3, 4, 5.
  • each underlay location area 27, 28, 29 comprises at least one microcell.
  • underlay location area 27 comprises of one microcell 11 and is shown in FIG. 1 by horizontal shading.
  • Underlay location area 28 comprises of two microcells 12, 13 and is shown by left to right diagonal shading.
  • Underlay location area 29 comprises of two microcells 10, 14 and is shown by vertical shading.
  • the number of microcells that are included in an underlay location area may be smaller than then the number of macrocells included in an overlay location area.
  • the minimum number of microcells that are included within an underlay location area is one.
  • the smaller number of microcells in an underlay location area allow for detecting more location update requests for a fast moving mobile station.
  • a method of planning a multicellular environment having overlay and underlay location areas includes assigning a first number of macrocells to an overlay location area and assigning a second number of microcells to an underlay location area where the second number may be smaller than the first number.
  • a flow chart is shown for a method of determining a handover for a mobile station in a multicellular environment as described above including the steps of measuring time between a message received at a base station for the mobile station and determining a handover in dependence upon the measured time.
  • the message is a location update request also known as LU REQ in GSM specifications.
  • the flow chart of FIG. 2 shows, according to a preferred embodiment of the present invention, that when a mobile station is powered up and in normal idle mode operation as in step 101, it waits until a location update (LU) is requested.
  • a location update For example, in normal idle operation, step 101, when a mobile crosses a location area and there is a better cell in that area, it will camp on to that cell and request a location update.
  • the infrastructure will analyse the request. If it is determined that the request is not a location update from a microcell to another microcell, then the normal update procedure is followed as in step 106 (and as defined in GSM specifications).
  • the infrastructure determines that the location update is from a microcell to a microcell, then the time between the last location update request is determined by the base station 103. If it is the first location update request then the base station stores the time and waits until the next location update request to determine time between requests. Similarly, a rate of time may be determined between requests as well as over a number of requests to get an average rate. The location update rate is determined with respect to time. Thus, time may be measured between location updates to get a location update rate.
  • the mobile station is handed over to a macrocell as in step 105.
  • step 104 If the time is below a predetermined threshold as decided in step 104, then the mobile follows the normal location update procedures.
  • the process to force the mobile station on to the macrocell can be achieved in several ways.
  • One possible implementation is as follows:
  • Infrastructure sends LU accept for the microcell. 4)
  • the infrastructure forces the mobile to handover to macrocell cell network using normal handover procedures.
  • the present invention defines a process in a base station or BSS which enables slow moving mobiles to stay on the microcellular network, whilst fast moving mobiles are put on the macrocellular network. It uses rate or time between location update requests (within microcells) from a mobile station to indicate the speed of the mobile. Mobile stations requesting location updates often are deemed to be moving quickly and are moved to an available macrocell. Mobile stations requesting location updates less often are kept on microcells. It is also important that the Cl settings and the RF planning ensures that microcells are stronger candidate cells than macrocells.
  • the invention proposes that there is an underlay/overlay of location areas assigned.
  • the macrocell location areas maybe created as normal, with for example 20 cells per location area.
  • the microcellular network will have fewer cells per location area.
  • the minimum number will be typically one cell per location are in densely populated urban areas.
  • the signalling traffic will not be significantly affected by this microcell location area topology as the invention works to move mobile stations with high location update rates on to macrocells.
  • the location update rate will not be significantly higher than that of a standard network.
  • the cell reselect hysteresis for location areas needs to be made high foi the macrocells so that once a mobile has moved on to the macrocell it is difficult to move back on to the microcell.
  • Mobile stations are encouraged on to microcells by the favourable signal levels and Cl settings. If they are moving quickly they will be moved to macrocells by the network and held there by the process of cell reselect hysteresis.
  • This invention enables operators of existing GSM phase one networks to increase the capacity of the network by adding a microcell underlay network.
  • the operation of the existing infra-structure and phase 1 mobiles is unaffected.
  • the present invention offers an opportunity to build a network underneath an existing network GSM digital cellular network and efficiently use valuable spectrum allocation.
  • the present invention provides a method of efficiently planning and implementing handovers for mobile stations in such multicellular environments.

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

Abstract

Système de communications tel celui montré sur la figure, destiné à un environnement multicellulaire et possédant une zone localisée de recouvrement ainsi qu'une pluralité de zones localisées sous-jacentes se situant au moins partiellement dans la zone de recouvrement et possédant chacune un nombre de microcellules qui peut être inférieur au nombre de macrocellules de la zone de recouvrement.
PCT/EP1995/003152 1994-08-10 1995-08-09 Systeme et procede de communications destinees a un environnement multicellulaire WO1996005708A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU33435/95A AU3343595A (en) 1994-08-10 1995-08-09 Communications system and method for a multicellular environment

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9416167.6 1994-08-10
GB9416167A GB2292288A (en) 1994-08-10 1994-08-10 Communications system and method for a multicellular environment

Publications (1)

Publication Number Publication Date
WO1996005708A1 true WO1996005708A1 (fr) 1996-02-22

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PCT/EP1995/003152 WO1996005708A1 (fr) 1994-08-10 1995-08-09 Systeme et procede de communications destinees a un environnement multicellulaire

Country Status (3)

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AU (1) AU3343595A (fr)
GB (1) GB2292288A (fr)
WO (1) WO1996005708A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5991286A (en) * 1997-02-20 1999-11-23 Telefonaktiebolaget L M Ericsson (Publ) Support of multiple modulation levels for a cellular packet control channel
US6061549A (en) * 1997-02-20 2000-05-09 Telefonaktiebolaget L M Ericsson Support of multiple modulation levels for a cellular traffic channel
US6278881B1 (en) 1997-06-30 2001-08-21 Telefonaktiebolaget Lm Ericsson (Publ) Mobile communications system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2316579B (en) * 1996-08-24 2000-10-04 Motorola Ltd Handover management system for cellular network
US6014564A (en) * 1996-09-19 2000-01-11 Nortel Networks Corporation Method and apparatus for determining virtual cell area
JP3019800B2 (ja) 1997-04-16 2000-03-13 日本電気株式会社 携帯電話機
EP2787776B1 (fr) * 2013-04-05 2016-06-22 Alcatel Lucent Réseau de télécommunications, station de base et procédé permettant de prévoir si une petite station de base cellulaire dans un groupe de petites stations de base cellulaire a une probabilité d'être accédée en premier au sein d'un groupe par des terminaux d'utilisateur

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04111700A (ja) * 1990-08-31 1992-04-13 Nippon Telegr & Teleph Corp <Ntt> 位置登録方式
EP0505106A2 (fr) * 1991-03-22 1992-09-23 Vodafone Limited Fractionnement de service dans les réseaux de télécommunications cellulaires et méthodes y afférant
EP0589278A2 (fr) * 1992-09-23 1994-03-30 Siemens Aktiengesellschaft Réseau radio mobile avec structure hiérarchique des cellules
EP0660635A2 (fr) * 1993-12-27 1995-06-28 Nec Corporation Procédé de transfert dans un système de communication mobile

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2242806B (en) * 1990-04-06 1994-04-20 Stc Plc Handover techniques
SE468696B (sv) * 1991-06-20 1993-03-01 Ericsson Telefon Ab L M Foerfarande att utfoera handover i ett mobilradiosystem med celler i flera skikt

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04111700A (ja) * 1990-08-31 1992-04-13 Nippon Telegr & Teleph Corp <Ntt> 位置登録方式
EP0505106A2 (fr) * 1991-03-22 1992-09-23 Vodafone Limited Fractionnement de service dans les réseaux de télécommunications cellulaires et méthodes y afférant
EP0589278A2 (fr) * 1992-09-23 1994-03-30 Siemens Aktiengesellschaft Réseau radio mobile avec structure hiérarchique des cellules
EP0660635A2 (fr) * 1993-12-27 1995-06-28 Nec Corporation Procédé de transfert dans un système de communication mobile

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 016, no. 354 (E - 1242) 30 July 1992 (1992-07-30) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5991286A (en) * 1997-02-20 1999-11-23 Telefonaktiebolaget L M Ericsson (Publ) Support of multiple modulation levels for a cellular packet control channel
US6061549A (en) * 1997-02-20 2000-05-09 Telefonaktiebolaget L M Ericsson Support of multiple modulation levels for a cellular traffic channel
US6278881B1 (en) 1997-06-30 2001-08-21 Telefonaktiebolaget Lm Ericsson (Publ) Mobile communications system

Also Published As

Publication number Publication date
GB2292288A (en) 1996-02-14
GB9416167D0 (en) 1994-09-28
AU3343595A (en) 1996-03-07

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