EP1338163A1 - Procede d'affectation de ressources radio a des stations mobiles, reseau de telecommunication et station mobile - Google Patents

Procede d'affectation de ressources radio a des stations mobiles, reseau de telecommunication et station mobile

Info

Publication number
EP1338163A1
EP1338163A1 EP00981249A EP00981249A EP1338163A1 EP 1338163 A1 EP1338163 A1 EP 1338163A1 EP 00981249 A EP00981249 A EP 00981249A EP 00981249 A EP00981249 A EP 00981249A EP 1338163 A1 EP1338163 A1 EP 1338163A1
Authority
EP
European Patent Office
Prior art keywords
time slot
mobile station
tdma frames
downlink
tdma
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP00981249A
Other languages
German (de)
English (en)
Inventor
Jussi Sipola
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Oyj
Original Assignee
Nokia Oyj
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 Nokia Oyj filed Critical Nokia Oyj
Publication of EP1338163A1 publication Critical patent/EP1338163A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2643—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using time-division multiple access [TDMA]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency

Definitions

  • the invention relates to a method for allocating radio resources in a telecommunications system to mobile stations transmitting data in time slots of TDMA (time division multiple access) frames in uplink direction and receiving data in time slots of TDMA frames in downlink direction.
  • the invention equally relates to such a telecommunications network and such a mobile station.
  • Mobile stations employed in telecommunication systems are usually designed as full-duplex or half duplex mobile stations .
  • Full-duplex mobile stations are able to receive speech in time slots of TDMA frames in a downlink direction and transmit speech in time slots of TDMA frames in an uplink direction at the same time. To this end, they require a receiver and a transmitter with their own hardware and a duplex filter for enabling receiver and transmitter of the mobile station to use the same antenna at the same time.
  • Half-duplex mobile stations are also able to transmit speech in time slots of TDMA frames in an uplink direction and receive speech in time slots of TDMA frames in a downlink direction, but not simultaneously. Accordingly, no duplex filters are needed and some of the hardware of receiver and transmitter can be shared. Therefore, half-duplex mobile stations are less complex and less expensive than full- duplex mobile stations.
  • GSM Global System for Mobile communication
  • Figure 1 illustrates the offset between downlink and uplink TDMA frame structures .
  • Three rows of time slots in the upper part of figure 1 represent the TDMA structures of three different frequencies cO, cl, c2 used in downlink direction from the cell serving a specific half-duplex mobile station.
  • Three rows of time slots in the middle part of figure 1 represent the TDMA structures of three different frequencies cO ' , cl ' , c2 ' used in uplink direction to the serving cell.
  • Frequencies cO and cO ' have a fixed distance, providing the fixed duplex distance in frequency; the same applies to frequencies cl, cl ' and c2, c2 ' .
  • Two rows of time slots at the bottom of figure 1 represent the TDMA structures of two different frequencies do, eO used for downlink connections by adjacent cells .
  • the rows are made up of subsequent TDMA frames, each frame being divided into 8 time slots 0-7.
  • the boundaries between the TDMA frames related to the connections to the serving cell are indicated by thick vertical lines.
  • the boundaries between the time slots are indicated for frequencies cO, c2 , cO ' , c2 ' , dO and eO by thin vertical lines.
  • the numerals 0-7 of the time slots are included for those TDMA frames used by the half-duplex mobile station considered in this example.
  • a timing advance procedure is performed by the mobile station to compensate for the variable propagation delay from the base station to the mobile station and back. Timing advance is realised by slightly advancing the transmission of the mobile station, as indicated in the figure by the black boxes in uplink timeslots 3.
  • time slot 3 of the TDMA frames in uplink direction always occurs at the same time as time slot 0 of the TDMA frames in downlink direction. This provides for the fixed duplex distance in time, not taking into account the small variation caused by the timing advance procedure.
  • time slot 3 is assigned to the mobile station for transmission and reception of speech signals.
  • the mobile station receives and transmits data alternately, each time slot used being emphasized and the sequence of time slots involved being indicated by arrows.
  • the mobile station Because of the offset between downlink and uplink TDMA frame structures, the mobile station has a known transition time for shifting from reception to transmission and back and also for carrying out neighbor cell measurements in between.
  • the first action indicated in figure 1 is reception Rx of speech data in time slot 3 of the first completely depicted TDMA frame of the downlink connection with frequency cO, followed by transmission Tx of speech data in time slot 3 of the first completely depicted TDMA frame of the uplink connection with corresponding frequency cO ' .
  • the mobile station has a transition period of two time slots for switching from reception to transmission.
  • the mobile station Before switching to the downlink direction for reception Rx again, the mobile station has time to monitor the downlink of an adjacent cell using frequency dO .
  • the transition period available for switching from transmission to monitoring is somewhat more than one time slot.
  • the transition period available for switching from monitoring to regular reception again is somewhat more than one time slot.
  • the reception Rx following the monitoring is carried out by using time slot 3 of the second completely depicted downlink TDMA frame of frequency cl. Accordingly, the next transmission Tx takes place in time slot 3 of the second completely depicted uplink TDMA frame of corresponding frequency cl ' .
  • the physical radio resource can be given to the user of another mobile station whenever the user of the first mobile station enters a silent period, i.e. stops either talking or receiving speech.
  • FIG 2 shows time slots of the downlink Rx and the uplink Tx connection to the serving cell and the time slots of the downlink connection to some neighboring cell.
  • Time slot 0 of the downlink TDMA frames of the serving cells corresponds in time to time slot 5 of the uplink TDMA frames of the serving cell and of the downlink TDMA frames for monitoring.
  • a mobile station receiving in a certain time slot 10, here time slot 0, of every second TDMA frame in downlink direction can be allocated one of 9 different time slots 11, here time slots 0, 1, ... , 7, 0, of the TDMA frames in uplink direction and the mobile station can use at least one time slot 12, here time slot 2, of the downlink TDMA frames for monitoring, while still having at least the same transition periods as a normal full-rate mobile station.
  • a method for allocating radio resources in a telecommunications system to mobile stations transmitting data in time slots of TDMA frames in uplink direction and receiving data in time slots of TDMA frames in downlink direction comprising in the case that a first mobile station is using a first time slot of TDMA frames in a first direction and requires a time slot of TDMA frames in the opposite direction and the corresponding time slot of TDMA frames in the opposite direction is used by a second mobile station, the steps of: a) determining a free time slot of the TDMA frames in the opposite direction; b) moving the connection of the second mobile station (B) to the determined free time slot of the TDMA frames in the opposite direction and c) allocating the corresponding time slot of the TDMA frames in the opposite direction to the first mobile station.
  • the object is equally reached by a telecommunications network and a mobile station comprising means for realizing the method according to the invention.
  • the invention proceeds from an approach which is quite different from the approach known from the state of the art. It is proposed not to determine a free time slot for the mobile station having a connection in one direction and requiring an additional one in the opposite direction. Rather, a free time slot is sought for the second mobile station occupying the time slot corresponding to the time slot used by the first mobile station in the direction already used. Since the second mobile station can only be working in the opposite direction at this time, any free time slot of the TDMA frames in the opposite direction can be chosen without restriction. To the first mobile station, on the other hand, the time slot corresponding to the time slot already used for the first direction is assigned for its connection in the opposite direction. The assignment of this time slot guarantees sufficient transition periods for switching between reception, transmission and a monitoring phase.
  • the invention therefore allows statistical multiplexing to be used on half-duplex mobile stations without reduction of trunking gain. If there are free resources available in the needed direction, it is always possible to move the second mobile station to this free resource. Accordingly, the method according to the invention allows for maximal trunking gain of statistical multiplexing. At the same time, the existing duplex distance can be kept in both, time and frequency domains .
  • the first direction can be the uplink and the opposite direction the downlink direction and equally, the first direction can be the downlink and the opposite direction the uplink direction.
  • the method according to the invention can be used in particular for statistical multiplexing of speech transmitted to and from mobile stations. If several frequencies are employed for uplink and downlink, the corresponding time slot is preferably the same time slot of a specified frequency assigned as up/downlink frequency to the used down/uplink frequency. In the example of figure 1 this would be cO and cO ' , cl and cl ' and c2 and c2 ' .
  • the other free time slot determined for use by the second mobile station can be any free time slot of the TDMA frames in the opposite direction of any employed frequency.
  • the corresponding time slot is preferably assigned to the first mobile station immediately.
  • the method according to the invention can be used either with full-rate or half-rate duplex channels, depending on the required quality of transmitted speech.
  • the allocation of the time slots is preferably performed by the network, in particular by the base station systems of the network, by sending assignment messages to the mobile stations .
  • the first mobile station uses a time slot of TDMA frames in uplink direction and requires a corresponding time slot of TDMA frames in downlink direction, only the transmission of one assignment message is necessary.
  • This assignment message is transmitted to the second mobile station to inform it about the new time slot to be used.
  • the first mobile station can be configured to always listen to the time slot of the downlink TDMA frames corresponding to the used time slot of the uplink TDMA frames and therefore begin reception on the corresponding time slot in downlink direction by itself.
  • a second assignment message can be transmitted to the first mobile station to allow the first mobile station to begin reception on the corresponding time slot of TDMA frames in downlink direction.
  • a first assignment message is transmitted to the second mobile station for moving its transmission to the determined free time slot of the TDMA frames in uplink direction and a second assignment message is transmitted to the first mobile station for allowing it to start transmitting on the corresponding time slot of the TDMA frames in uplink direction.
  • the assignment messages are transmitted in the headers of downlink speech frames.
  • the assignments can be transmitted by stealing frames or via special signaling channels.
  • GSM/EDGE RAN GSM/EDGE RAN; EDGE: Enhanced Data rates for GSM Evolution, RAN: Radio Access Network
  • EGPRS Enhanced General Packet Radio Service
  • Fig. 1 shows the switching of a half-duplex mobile station between uplink and downlink direction
  • Fig. 2 illustrates a known allocation method of time slots for a half-duplex half-rate channel mobile station
  • Fig. 3a shows a situation where an allocation of a second time slot for one mobile station becomes necessary
  • Fig. 3b shows an allocation according to the state of the art in a situation of Fig. 3a
  • Fig. 3c shows an allocation according to the invention in a situation of Fig. 3a.
  • Figures 3a-3c illustrate the principle of the method according to the invention used in a telecommunications system with TDMA structures in uplink and downlink direction as shown by Figure 1. If a speech connection has to be established only in one direction for the mobile station of a certain user, there are no duplex considerations necessary and any free time slot is assigned to the mobile station. Figures 3a-3c deals with the case that for mobile station A there is speech in one direction and a speech period begins also in the other direction, while the corresponding duplex resource is already used by another mobile station B.
  • Figures 3a-c show four time slots 1-4 of a TDMA frame for each, downlink and uplink. There is an offset between the corresponding TDMS frames so that time slot 4 of the downlink corresponds in time with time slot 1 of the uplink.
  • user A with mobile station A wants to start speech mode also in downlink direction.
  • Figure 3c shows the solution according to the invention for half-duplex mobile stations.
  • the network first chooses any free time slot of the TDMA frames in downlink direction, here time slot 4. Then it sends an assignment message via a special signaling channel to mobile station B, informing mobile station B that it has to switch to this free time slot. According to the assignment message, reception of mobile station B is moved from time slot 1 to time slot 4 of the TDMA frames in downlink direction and time slot 1 of the TDMA frames in downlink direction is released for use by mobile station A.
  • all half-duplex mobile stations are continuously listening to the channel corresponding to its uplink channel. An assignment message to mobile station A is therefore not necessary for assigning time slot 1 of the TDMA frames in downlink direction to mobile station A, which starts receiving on time slot 1 of the TDMA frames in downlink direction by itself.
  • a mobile station can always be assigned the same time slot of the TDMA frames in uplink and downlink direction. Therefore, a sufficient transition period for switching between transmitting, receiving and monitoring is guaranteed at all times.
  • the mobile stations can be simple half-duplex full-rate channel mobile stations, while at the same time, the advantages of statistical multiplexing are assured.
  • the method according to the invention is used with half- duplex half-rate channels, the known statistical multiplexing for half-rate channel mobile stations is even improved.
  • the allocation of mobile station B is completely independent, any free time slot of any frequency in the downlink can be used.
  • the known half- duplex half-rate channel method only 9 out of 16 (or 10 out of 16 if the monitoring function is neglected) are candidates for selection, as described in the introduction.

Landscapes

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

Abstract

L'invention concerne un procédé d'affectation de ressources radio à des stations mobiles (A, B, C) dans un réseau de télécommunication, lesdites stations mobiles transmettant de manière ascendante des données dans des créneaux de séquences TDMA, et recevant de manière descendante des données dans des créneaux de séquences TDMA. L'invention concerne également un tel réseau de télécommunication et une telle station mobile. L'invention vise à améliorer l'affectation. A cet effet, lorsqu'une première station mobile (A) utilise un premier créneau (1) dans un premier sens, et requiert un créneau dans le sens opposé, et lorsqu'une deuxième station mobile (B) utilise le créneau correspondant à distance bilatérale fixe (1) dans le sens opposé, ledit procédé consiste a) à déterminer un créneau libre (4) dans le sens opposé ; b) à déplacer la connexion de la deuxième station mobile (B) vers le créneau libre (4) déterminé dans le sens opposé ; et, c) à affecter à la première station mobile (A) le créneau correspondant à distance bilatérale fixe (1) dans le sens opposé.
EP00981249A 2000-11-11 2000-11-11 Procede d'affectation de ressources radio a des stations mobiles, reseau de telecommunication et station mobile Withdrawn EP1338163A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2000/011175 WO2002039774A1 (fr) 2000-11-11 2000-11-11 Procede d'affectation de ressources radio a des stations mobiles, reseau de telecommunication et station mobile

Publications (1)

Publication Number Publication Date
EP1338163A1 true EP1338163A1 (fr) 2003-08-27

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP00981249A Withdrawn EP1338163A1 (fr) 2000-11-11 2000-11-11 Procede d'affectation de ressources radio a des stations mobiles, reseau de telecommunication et station mobile

Country Status (3)

Country Link
EP (1) EP1338163A1 (fr)
AU (1) AU2001218566A1 (fr)
WO (1) WO2002039774A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2488784C (fr) * 2002-06-27 2009-12-29 Nokia Corporation Procede d'ordonnancement et dispositif de transmission en semi-duplex
KR20060129014A (ko) 2004-02-12 2006-12-14 노키아 코포레이션 Ｔｄｍａ 셀룰러 통신 시스템의 무선자원 할당 방법,시스템, 장치 그리고 컴퓨터 프로그램
KR101092235B1 (ko) * 2009-09-23 2011-12-12 재단법인대구경북과학기술원 무선자원 할당장치 및 무선자원 할당방법
EP3031240B1 (fr) * 2013-08-09 2018-04-25 Telefonaktiebolaget LM Ericsson (publ) Appareil et procédé permettant d'améliorer le transfert dans un système mondial de communications mobiles

Family Cites Families (4)

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Publication number Priority date Publication date Assignee Title
US5420851A (en) * 1993-11-24 1995-05-30 At&T Corp. Method of multiple access
FI113223B (fi) * 1995-10-23 2004-03-15 Nokia Corp Menetelmä, laite ja televerkko törmäysten välttämiseksi radioliikenteessä
DE19743350C2 (de) * 1997-09-30 2000-05-04 Siemens Ag Verfahren und Kommunikationssystem zur drahtlosen Informationsübertragung
DE69928151T2 (de) * 1998-02-26 2006-07-20 Alcatel Gesprächsaufbau für Notrufe in einem TDD System

Non-Patent Citations (1)

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Title
See references of WO0239774A1 *

Also Published As

Publication number Publication date
WO2002039774A1 (fr) 2002-05-16
AU2001218566A1 (en) 2002-05-21

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