SIST ETS 300 911 E1:2003
(Main)Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem link control (GSM 05.08 version 5.2.1)
Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem link control (GSM 05.08 version 5.2.1)
This European Telecommunication Standard (ETS) specifies the Radio sub-system link control implemented in the Mobile Station (MS), Base Station System (BSS) and Mobile Switching Centre (MSC) of the GSM and DCS 1800 systems. Unless otherwise specified, references to GSM also include DCS 1800.
Digitalni celični telekomunikacijski sistem (faza 2+) – Krmiljenje povezave radijskega podsistema (GSM 05.08, različica 5.2.1)
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem link control (GSM 05.08 version 5.2.1)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:ETS 300 911 Edition 1SIST ETS 300 911 E1:2003en01-december-2003SIST ETS 300 911 E1:2003SLOVENSKI
STANDARD
SIST ETS 300 911 E1:2003
EUROPEANETS 300 911TELECOMMUNICATIONMay 1997STANDARDSource: ETSI TC-SMGReference: DE/SMG-020508QR1ICS:33.020Key words:Digital cellular telecommunications system, Global System for Mobile communications (GSM)GLOBAL SYSTEM
FOR MOBILE COMMUNICATIONSRDigital cellular telecommunications system (Phase 2+);Radio subsystem link control(GSM 05.08 version 5.2.1)ETSIEuropean Telecommunications Standards InstituteETSI SecretariatPostal address: F-06921 Sophia Antipolis CEDEX - FRANCEOffice address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCEX.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.frTel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and theforegoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1997. All rights reserved.SIST ETS 300 911 E1:2003
Page 2ETS 300 911 (GSM 05.08 version 5.2.1): May 1997Whilst every care has been taken in the preparation and publication of this document, errors in content,typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to"ETSI Editing and Committee Support Dept." at the address shown on the title page.SIST ETS 300 911 E1:2003
Page 3ETS 300 911 (GSM 05.08 version 5.2.1): May 1997ContentsForeword.51Scope.71.1Normative references.71.2Abbreviations.82General.83Handover.93.1Overall process.93.2MS measurement procedure.93.3BSS measurement procedure.93.4Strategy.94RF power control.104.1Overall process.104.2MS implementation.104.3MS power control range.104.4BSS implementation.104.5BSS power control range.104.6Strategy.104.7Timing.114.8Dedicated channels used for a voice group call or voice broadcast.115Radio link failure.115.1Criterion.115.2MS procedure.115.3BSS procedure.126Idle mode tasks.126.1Introduction.126.2Measurements for normal cell selection.136.3Measurements for stored list cell selection.136.4Criteria for cell selection and reselection.146.5Downlink signalling failure.156.6Measurements for Cell Reselection.156.6.1Monitoring of received level and BCCH data.156.6.2Path loss criteria and timings for cell re-selection.166.7Release of TCH and SDCCH.176.7.1Normal case.176.7.2Call re-establishment.176.8Abnormal cases and emergency calls.187Network pre-requisites.187.1BCCH carriers.187.2Identification of surrounding BSS for handover measurements.188Radio link measurements.198.1Signal strength.208.1.1General.208.1.2Physical parameter.208.1.3Statistical parameters.218.1.4Range of parameter.218.2Signal quality.218.2.1General.218.2.2Physical parameter.21SIST ETS 300 911 E1:2003
Page 4ETS 300 911 (GSM 05.08 version 5.2.1): May 19978.2.3Statistical parameters.228.2.4Range of parameter.228.3Aspects of discontinuous transmission (DTX).238.4Measurement reporting.248.5Absolute MS-BTS distance.278.5.1General.278.5.2Physical parameter.279Control parameters.28Annex A (informative):Definition of a basic GSM or DCS 1 800 handover and RF power controlalgorithm.31A.1Scope.31A.2Functional requirement.31A.3BSS pre-processing and threshold comparisons.31A.3.1Measurement averaging process.32A.3.2Threshold comparison process.33A.3.2.1RF power control process.33A.3.2.2Handover Process.34A.4BSS decision algorithm.35A.4.1Internal intracell handover according to radio criteria: (Interference problems).35A.4.2Internal handover according to other criteria.36A.4.3General considerations.36A.5Channel allocation.36A.6Handover decision algorithm in the MSC.36History.39SIST ETS 300 911 E1:2003
Page 5ETS 300 911 (GSM 05.08 version 5.2.1): May 1997ForewordThis European Telecommunication Standard (ETS) has been produced by the Special Mobile Group(SMG) Technical Committee (TC) of the European Telecommunications Standards Institute (ETSI).This ETS specifies the Radio sub-system link control implemented in the Mobile Station (MS), BaseStation System (BSS) and Mobile Switching Centre (MSC) of the digital mobile cellular and personalcommunication systems operating in the 900 MHz and 1 800 MHz band (GSM 900 and DCS 1 800).This ETS is a GSM technical specification version 5, which incorporates GSM Phase 2+enhancements/features to the version 4 GSM technical specification. The ETS from which this Phase 2+ETS has evolved is Phase 2 GSM ETS 300 578 Edition 7 (GSM 05.08 version 4.17.0).The contents of this ETS is subject to continuing work within TC-SMG and may change following formalTC-SMG approval. Should TC-SMG modify the contents of this ETS, it will be resubmitted for OAP byETSI with an identifying change of release date and an increase in version number as follows:Version 5.x.ywhere:ythe third digit is incremented when editorial only changes have been incorporated in thespecification;xthe second digit is incremented for all other types of changes, i.e. technical enhancements,corrections, updates, etc.The specification from which this ETS has been derived was originally based on CEPT documentation,hence the presentation of this ETS may not be entirely in accordance with the ETSI rules.Transposition datesDate of adoption:18 April 1997Date of latest announcement of this ETS (doa):31 August 1997Date of latest publication of new National Standardor endorsement of this ETS (dop/e):28 February 1998Date of withdrawal of any conflicting National Standard (dow):28 February 1998SIST ETS 300 911 E1:2003
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Page 7ETS 300 911 (GSM 05.08 version 5.2.1): May 19971ScopeThis European Telecommunication Standard (ETS) specifies the Radio sub-system link controlimplemented in the Mobile Station (MS), Base Station System (BSS) and Mobile Switching Centre (MSC)of the GSM and DCS 1 800 systems.Unless otherwise specified, references to GSM also include DCS 1 800.1.1Normative referencesThis ETS incorporates by dated and undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listedhereafter. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this ETS only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies.[1]GSM 01.04 (ETR 350): "Digital cellular telecommunications system (Phase 2+);Abbreviations and acronyms".[2]GSM 03.03 (ETS 300 927): "Digital cellular telecommunications system(Phase 2+); Numbering, addressing and identification".[3]GSM 03.09: "Digital cellular telecommunications system (Phase 2+); Handoverprocedures".[4]GSM 03.22 (ETS 300 930): "Digital cellular telecommunications system(Phase 2+); Functions related to Mobile Station (MS) in idle mode and groupreceive mode".[5]GSM 04.04 (ETS 300 936): "Digital cellular telecommunications system; Layer 1General requirements".[6]GSM 04.06 (ETS 300 938): "Digital cellular telecommunications system; MobileStation - Base Station System (MS - BSS) interface; Data Link (DL) layerspecification".[7]GSM 04.08 (ETS 300 940): "Digital cellular telecommunications system(Phase 2+); Mobile radio interface layer 3 specification".[8]GSM 05.02 (ETS 300 908): "Digital cellular telecommunications system(Phase 2+); Multiplexing and multiple access on the radio path".[9]GSM 05.05 (ETS 300 910): "Digital cellular telecommunications system(Phase 2+); Radio transmission and reception".[10]GSM 05.10 (ETS 300 912): "Digital cellular telecommunications system(Phase 2+); Radio subsystem synchronization".[11]GSM 06.11 (ETS 300 962): "Digital cellular telecommunications system; Fullrate speech; Substitution and muting of lost frames for full rate speechchannels".[12]GSM 08.08: "Digital cellular telecommunications system (Phase 2+); MobileSwitching Centre - Base Station System (MSC - BSS) interface; Layer 3specification".[13]GSM 08.58: "Digital cellular telecommunications system (Phase 2+); BaseStation Controller - Base Transceiver Station (BSC - BTS) interface; Layer 3specification".SIST ETS 300 911 E1:2003
Page 8ETS 300 911 (GSM 05.08 version 5.2.1): May 1997[14]GSM 11.10 (ETS 300 607): "Digital cellular telecommunications system(Phase 2+); Mobile Station (MS) conformity specification".[15]GSM 11.20 (ETS 300 609): "Digital cellular telecommunications system(Phase 2); The GSM Base Station System (BSS) equipment specification".1.2AbbreviationsAbbreviations used in this ETS are listed in GSM 01.04.2GeneralThe radio sub-system link control aspects that are addressed are as follows:-Handover;-RF Power control;-Radio link Failure;-Cell selection and re-selection in Idle mode, and in Group Receive mode.Handover is required to maintain a call in progress as a MS engaged in a point-to-point call or with accessto the uplink of a channel used for a voice group call passes from one cell coverage area to another andmay also be employed to meet network management requirements, e.g. relief of congestion.Handover may occur during a call from one TCH or multiple TCHs (in the case of multislot configuration)to another TCH or multiple TCHs. It may also occur from DCCH to DCCH or from DCCH to one ormultiple TCH(s), e.g. during the initial signalling period at call set-up.The handover may be either from channel(s) on one cell to other channel(s) on a surrounding cell, orbetween channels on the same cell which are carried on the same frequency band. Examples are given ofhandover strategies, however, these will be determined in detail by the network operator.For a multiband MS, specified in GSM 02.06, the handover described is also allowed between anychannels on different cells which are carried on different frequency bands, e.g. between a GSM 900/TCHand a DCS 1 800/TCH. Handover between two co-located cells, carried on different frequency bands, isconsidered as inter-cell handover irrespective of the handover procedures used.Adaptive control of the RF transmit power from an MS and optionally from the BSS is implemented inorder to optimize the uplink and downlink performance and minimize the effects of co-channel interferencein the system.The criteria for determining radio link failure are specified in order to ensure that calls which fail eitherfrom loss of radio coverage or unacceptable interference are satisfactorily handled by the network. Radiolink failure may result in either re-establishment or release of the call in progress. For channels used for avoice group call, an radio uplink failure results in the freeing up of the uplink.Procedures for cell selection and re-selection whilst in Idle mode (i.e. not actively processing a call), arespecified in order to ensure that a mobile is camped on a cell with which it can reliably communicate onboth the radio uplink and downlink. The operations of an MS in Idle Mode are specified in GSM 03.22.An MS listening to a voice group call or a voice broadcast use cell re-selection procedures to change cell.This may be supported by a list of cells carrying the voice group or voice broadcast call downlink, providedto the MS by the network. The operations of an MS in Group Receive Mode are specified in GSM 03.22.Information signalled between the MS and BSS is summarized in tables 1 and 2. A full specification of theLayer 1 header is given in GSM 04.04, and of the Layer 3 fields in GSM 04.08.SIST ETS 300 911 E1:2003
Page 9ETS 300 911 (GSM 05.08 version 5.2.1): May 19973Handover3.1Overall processThe overall handover process is implemented in the MS, BSS and MSC. Measurement of radiosubsystem downlink performance and signal strengths received from surrounding cells, is made in theMS. These measurements are signalled to the BSS for assessment. The BSS measures the uplinkperformance for the MS being served and also assesses the signal strength of interference on its idletraffic channels. Initial assessment of the measurements in conjunction with defined thresholds andhandover strategy may be performed in the BSS. Assessment requiring measurement results from otherBTS or other information resident in the MSC, may be performed in the MSC.GSM 03.09 describes the handover procedures to be used in PLMNs.3.2MS measurement procedureA procedure shall be implemented in the MS by which it monitors the downlink RX signal level and qualityfrom its serving cell and the downlink RX signal level and BSIC of surrounding BTS. The method ofidentification of surrounding BTS is described in subclause 7.2. The requirements for the MSmeasurements are given in subclause 8.1.3.3BSS measurement procedureA procedure shall be implemented in the BSS by which it monitors the uplink RX signal level and qualityfrom each MS being served by the cell. In the case of a multislot configuration the evaluation shall beperformed on a timeslot per timeslot basis. A procedure shall be implemented by which the BSS monitorsthe levels of interference on its idle traffic channels.3.4StrategyThe handover strategy employed by the network for radio link control determines the handover decisionthat will be made based on the measurement results reported by the MS/BSS and various parameters setfor each cell. Network directed handover may also occur for reasons other than radio link control, e.g. tocontrol traffic distribution between cells. The exact handover strategies will be determined by the networkoperator, a detailed example of a basic overall algorithm appears in annex A. Possible types of handoverare as follows:Inter-cell handover:Intercell handover from the serving cell to a surrounding cell will normally occur either when thehandover measurements show low RXLEV and/or RXQUAL on the current serving cell and a betterRXLEV available from a surrounding cell, or when a surrounding cell allows communication with alower TX power level. This typically indicates that an MS is on the border of the cell area.Intercell handover may also occur from the DCCH on the serving cell to a TCH or multislotconfiguration on another cell during call establishment. This may be used as a means of providingsuccessful call establishment when no TCH resource is available on the current serving cell.Inter-cell handover between cells using different frequency bands is allowed for a multi band MS.Intra-cell handover:Intra-cell handover from one channel/timeslot in the serving cell to another channel/timeslot in thesame cell will normally be performed if the handover measurements show a low RXQUAL, but ahigh RXLEV on the serving cell. This indicates a degradation of quality caused by interference eventhough the MS is situated within the serving cell. The intra-cell handover should provide a channelwith a lower level of interference. Intra-cell handover can occur either to a timeslot on a new carrieror to a different timeslot on the same carrier. Similarly, intra-cell handover may occur betweendifferent multislot configurations in the same cell. These multislot configurations may comprisedifferent number of timeslots and may partly overlap.GSM 08.08 defines the causes for handover that may be signalled from BSS to MSC.SIST ETS 300 911 E1:2003
Page 10ETS 300 911 (GSM 05.08 version 5.2.1): May 19974RF power control4.1Overall processRF power control is employed to minimize the transmit power required by MS or BSS whilst maintainingthe quality of the radio links. By minimizing the transmit power levels, interference to co-channel users isreduced.4.2MS implementationRF power control shall be implemented in the MS.The power control level to be employed by the MS on each uplink channel is indicated by means of thepower control information sent either in the layer 1 header of each SACCH message block (seeGSM 04.04) on the corresponding downlink channel, or in a dedicated signalling block (see GSM 04.08).The MS shall employ the most recently commanded power control level appropriate to each channel for alltransmitted bursts on either a TCH (including handover access burst), FACCH, SACCH or SDCCH.The MS shall confirm the power control level that it is currently employing in the SACCH L1 header oneach uplink channel. The indicated value shall be the power control level actually used by the mobile forthe last burst of the previous SACCH period.In case of a multislot configuration, each bi-directional channel shall be power controlled individually by thecorresponding SACCH. Power control information on downlink unidirectional channels shall be neglected.When accessing a cell on the RACH (random access) and before receiving the first power commandduring a communication on a DCCH or TCH (after an IMMEDIATE ASSIGNMENT), all GSM and class 1and class 2 DCS 1 800 MS shall use the power level defined by the MS_TXPWR_MAX_CCH parameterbroadcast on the BCCH of the cell. The class 3 DCS 1 800 MS shall use the power level defined by MSTXPWR MAX CCH plus the value POWER OFFSET also broadcast on the BCCH of the cell.If a power control level defined in 05.05 is received but the level is not supported by the MS, the MS shalluse the supported output power which is closest to the output power indicated by the received powercontrol level.4.3MS power control rangeThe range over which a MS shall be capable of varying its RF output power shall be from its maximumoutput down to its minimum, in steps of nominally 2 dB.GSM 05.05 gives a detailed definition of the RF power level step size and tolerances.4.4BSS implementationRF power control may optionally be implemented in the BSS.4.5BSS power control rangeThe range over which the BSS shall be capable of reducing its RF output power from its maximum levelshall be nominally 30 dB, in 15 steps of nominally 2 dB.GSM 05.05 gives a detailed definition of the RF power level step size and tolerances.4.6StrategyThe RF power control strategy employed by the network determines the ordered power level that issignalled to the MS, and the power level that is employed by the BSS.The power level to be employed in each case will be based on the measurement results reported by theMS/BTS and various parameters set for each cell. The exact strategies will be determined by the networkoperator. A detailed example of a basic algorithm appears in annex A.SIST ETS 300 911 E1:2003
Page 11ETS 300 911 (GSM 05.08 version 5.2.1): May 19974.7TimingUpon receipt of a command from an SACCH to change its power level on the corresponding uplinkchannel, the MS shall change to the new level at a rate of one nominal 2 dB power control step every60 ms (13 TDMA frames), i.e. a range change of 15 steps should take about 900 ms. The change shallcommence at the first TDMA frame belonging to the next reporting period (as specified in subclause 8.4).The MS shall change the power one nominal 2 dB step at a time, at a rate of one step every 60 msfollowing the initial change, irrespective of whether actual transmission takes place or not.In case of channel change, the commanded power level shall be applied on each new channelimmediately.4.8Dedicated channels used for a voice group call or voice broadcastThe network shall not allocate the uplink of the channel used for a voice group call to more than one MS.If marked busy, no other MS shall transmit on the channel. This marking is indicated by the network, asdefined in GSM 03.68 and 04.08. Any MS allocated the uplink of a channel used for a voice group callshall only transmit if the uplink is marked busy, and shall stop using the uplink if it happens to becomemarked free. An MS not allocated the uplink may perform a random access procedure on the uplink togain access to talk, only if the uplink is marked as free.On a channel used during a voice group call, the uplink power control shall only apply to the MS currentlyallocated that uplink, and the MS power control level ordered by the network shall be ignored by all otherMSs listening to the downlink.When performing a random access on a cell to gain access to the uplink of a channel used for a voicegroup call, until receiving the first dedicated power command from the network, the MS shall use the lastreceived power level command as defined by the MS_TXPWR_MAX_CCH parameter broadcast on theBCCH of the cell, or if MS_TXPWR_MAX_CCH corresponds to a power control level not supported by theMS as defined by its power class in GSM 05.05, the MS shall act as though the closest supported powercontrol level had been broadcast.RF downlink power control will normally not be applied on channels used for a voice group call or voicebroadcast.5Radio link failure5.1CriterionThe criterion for determining Radio Link Failure in the MS shall be based on the success rate of decodingmessages on the downlink SACCH. For a multislot configuration, only the main SACCH shall be used fordetermining Radio Link Failure.5.2MS procedureThe aim of determining radio link failure in the MS is to ensure that calls with unacceptable voice/dataquality, which cannot be improved either by RF power control or handover, are either re-established orreleased in a defined manner. In general the parameters that control the forced release should be setsuch that the forced release will not normally occur until the call has degraded to a quality below that atwhich the majority of subscribers would have manually released. This ensures that, for example, a call onthe edge of a radio coverage area, although of bad quality, can usually be completed if the subscriberwishes.The radio link failure criterion is based on the radio link counter S. If the MS is unable to decode a SACCHmessage (BFI=1),S is decreased by 1. In the case of a successful reception of a SACCH message(BFI=0) S is increased by 2. In any case S shall not exceed the value of RADIO_LINK_TIMEOUT. If Sreaches 0 a radio link failure shall be declared. The action to be taken is specified in GSM 04.08. TheRADIO_LINK_TIMEOUT parameter is transmitted by each BSS in the BCCH data (see table 1).The MS shall continue transmitting as normal on the uplink until S reaches 0.SIST ETS 300 911 E1:2003
Page 12ETS 300 911 (GSM 05.08 version 5.2.1): May 1997The algorithm shall start after the assignment of a dedicated channel and S shall be initialized toRADIO_LINK_TIMEOUT.The detailed operation shall be as follows:- The radio link time-out algorithm shall be stopped at the reception of a channel change command.- (Re-)initialization and start of the algorithm shall be done whenever the MS switches to a newchannel (this includes the old chan
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