SIST ETS 300 578 E9:2003
(Main)Digital cellular telecommunications system (Phase 2) (GSM); Radio subsystem link control (GSM 05.08 version 4.18.3)
Digital cellular telecommunications system (Phase 2) (GSM); Radio subsystem link control (GSM 05.08 version 4.18.3)
This European Telecommunication Standard (ETS) specifies the Radio sub -system link control implemented in the Mobile Station (MS), Base Stat ion 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.
Digitalni celični telekomunikacijski sistem (faza 2) – Krmiljenje povezave radijskega podsistema (GSM 05.08, različica 4.18.3 )
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 4.18.3)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:ETS 300 578 Edition 9SIST ETS 300 578 E9:2003en01-december-2003SIST ETS 300 578 E9:2003SLOVENSKI
STANDARD
SIST ETS 300 578 E9:2003
EUROPEANETS 300 578TELECOMMUNICATIONAugust 1997STANDARDNinth EditionSource: ETSI SMGReference: RE/SMG-020508PR8ICS:33.020Key words:Digital 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 4.18.3)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 300 578 E9:2003
Page 2ETS 300 578 (GSM 05.08 version 4.18.3): August 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 300 578 E9:2003
Page 3ETS 300 578 (GSM 05.08 version 4.18.3): August 1997ContentsForeword.51Scope.71.1Normative references.71.2Abbreviations.82General.83Handover.83.1Overall process.83.2MS measurement procedure.93.3BSS measurement procedure.93.4Strategy.94RF power control.94.1Overall process.94.2MS implementation.94.3MS power control range.104.4BSS implementation.104.5BSS power control range.104.6Strategy.104.7Timing.105Radio link failure.105.1Criterion.105.2MS procedure.115.3BSS procedure.116Idle mode tasks.116.1Introduction.116.2Measurements for normal cell selection.126.3Measurements for stored list cell selection.126.4Criteria for cell selection and reselection.136.5Downlink signalling failure.146.6Measurements for Cell Reselection.146.6.1Monitoring of received level and BCCH data.146.6.2Path loss criteria and timings for cell re-selection.156.7Release of TCH and SDCCH.166.7.1Normal case.166.7.2Call re-establishment.166.8Abnormal cases and emergency calls.167Network pre-requisites.177.1BCCH carriers.177.2Identification of surrounding BSS for handover measurements.178Radio link measurements.188.1Signal strength.198.1.1General.198.1.2Physical parameter.198.1.3Statistical parameters.208.1.4Range of parameter.208.2Signal quality.208.2.1General.208.2.2Physical parameter.208.2.3Statistical parameters.20SIST ETS 300 578 E9:2003
Page 4ETS 300 578 (GSM 05.08 version 4.18.3): August 19978.2.4Range of parameter.218.3Aspects of discontinuous transmission (DTX).228.4Measurement reporting.228.5Absolute MS-BTS distance.258.5.1General.258.5.2Physical parameter.259Control parameters.26Annex A (informative):Definition of a basic GSM or DCS 1 800 handover and RF power controlalgorithm.29A.1Scope.29A.2Functional requirement.29A.3BSS pre-processing and threshold comparisons.29A.3.1Measurement averaging process.30A.3.2Threshold comparison process.31A.3.2.1RF power control process.31A.3.2.2Handover Process.32A.4BSS decision algorithm.33A.4.1Internal intracell handover according to radio criteria: (Interference problems).33A.4.2Internal handover according to other criteria.34A.4.3General considerations.34A.5Channel allocation.34A.6Handover decision algorithm in the MSC.34History.37SIST ETS 300 578 E9:2003
Page 5ETS 300 578 (GSM 05.08 version 4.18.3): August 1997ForewordThis European Telecommunication Standard (ETS) has been produced by the Special Mobile Group(SMG) 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 GSM and DCS 1 800 systems of theDigital cellular telecommunications system (Phase 2). Unless stated, references to GSM also includeDCS 1 800.The specification from which this ETS has been derived was originally based on CEPT documentation,hence the presentation of this draft ETS is not in accordance with the ETSI/PNE Rules.Transposition datesDate of adoption:25 July 1997Date of latest announcement of this ETS (doa):30 November 1997Date of latest publication of new National Standardor endorsement of this ETS (dop/e):31 May 1998Date of withdrawal of any conflicting National Standard (dow):31 May 1998SIST ETS 300 578 E9:2003
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Page 7ETS 300 578 (GSM 05.08 version 4.18.3): August 19971ScopeThis European Telecommunications 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 100): "Digital cellular telecommunications system (Phase 2);Abbreviations and acronyms".[2]GSM 03.03 (ETS 300 523): "Digital cellular telecommunications system(Phase 2); Numbering, addressing and identification".[3]GSM 03.09 (ETS 300 527): "Digital cellular telecommunications system(Phase 2); Handover procedures".[4]GSM 03.22 (ETS 300 535): "Digital cellular telecommunications system(Phase 2); Functions related to Mobile Station (MS) in idle mode".[5]GSM 04.04 (ETS 300 553): "Digital cellular telecommunications system(Phase 2); Layer 1; General requirements".[6]GSM 04.06 (ETS 300 555): "Digital cellular telecommunications system(Phase 2); Mobile Station - Base Station System (MS - BSS) interface; Data Link(DL) layer specification".[7]GSM 04.08 (ETS 300 557): "Digital cellular telecommunications system(Phase 2); Mobile radio interface layer 3 specification".[8]GSM 05.02 (ETS 300 574): "Digital cellular telecommunications system(Phase 2); Multiplexing and multiple access on the radio path".[9]GSM 05.05 (ETS 300 577): "Digital cellular telecommunications system(Phase 2); Radio transmission and reception".[10]GSM 05.10 (ETS 300 579): "Digital cellular telecommunications system(Phase 2); Radio subsystem synchronization".[11]GSM 06.11 (ETS 300 580-3): "Digital cellular telecommunications system(Phase 2); Substitution and muting of lost frames for full rate speech channels".[12]GSM 08.08 (ETS 300 590): "Digital cellular telecommunications system(Phase 2); Mobile Switching Centre - Base Station System (MSC - BSS)interface; Layer 3 specification".[13]GSM 08.58 (ETS 300 596): "Digital cellular telecommunications system(Phase 2); Base Station Controller - Base Transceiver Station (BSC - BTS)interface; Layer 3 specification".[14]GSM 11.10 (ETS 300 607): "Digital cellular telecommunications system(Phase 2); Mobile Station (MS) conformity specification".SIST ETS 300 578 E9:2003
Page 8ETS 300 578 (GSM 05.08 version 4.18.3): August 19971.2AbbreviationsAbbreviations 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.Handover is required to maintain a call in progress as a MS passes from one cell coverage area toanother and may also be employed to meet network management requirements, e.g. relief of congestion.Handover may occur during a call from TCH to TCH, it may also occur from DCCH to DCCH or fromDCCH to TCH, e.g. during the initial signalling period at call set-up.The handover may be either from a channel on one cell to another channel 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.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.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 04.08.3Handover3.1Overall 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.SIST ETS 300 578 E9:2003
Page 9ETS 300 578 (GSM 05.08 version 4.18.3): August 19973.2MS 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. A procedure shall be implemented by which the BSS monitors thelevels 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 on another cellduring call establishment. This may be used as a means of providing successful call establishmentwhen 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.GSM 08.08 defines the causes for handover that may be signalled from BSS to MSC.4RF 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 is indicated by means of the power control informationsent either in the layer 1 header of each downlink SACCH message block (see GSM 04.04), or in adedicated signalling block (see GSM 04.08).The MS shall employ the most recently commanded power control level appropriate to the channel for alltransmitted bursts on either a TCH (including handover access burst), FACCH, SACCH or SDCCH.SIST ETS 300 578 E9:2003
Page 10ETS 300 578 (GSM 05.08 version 4.18.3): August 1997The MS shall confirm the power control level that it is currently employing in the uplink SACCH L1 header.The indicated value shall be the power control level actually used by the mobile for the last burst of theprevious SACCH period.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 GSM 05.05 is received but the level is not supported by the MS, the MSshall use 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.4.7TimingUpon receipt of a command from the SACCH to change its power level, the MS shall change to the newlevel at a rate of one nominal 2 dB power control step every 60 ms (13 TDMA frames), i.e. a range changeof 15 steps should take about 900 ms. The change shall commence at the first TDMA frame belonging tothe next reporting period (as specified in subclause 8.4). The MS shall change the power one nominal2 dB step at a time, at a rate of one step every 60 ms following the initial change, irrespective of whetheractual transmission takes place or not.In case of channel change, the commanded power level shall be applied on the new channel immediately.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.SIST ETS 300 578 E9:2003
Page 11ETS 300 578 (GSM 05.08 version 4.18.3): August 19975.2MS 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.The 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 channel in assignment and handover failure cases), at the latest whenthe main signalling link (see GSM 04.08) has been established.- The RADIO_LINK_TIMEOUT value used at (re-)initialization shall be that used on the previouschannel (in the Immediate Assignment case the value received on the BCCH), or the value receivedon SACCH if the MS has received a RADIO_LINK_TIMEOUT value on the new channel before theinitialization.- If the first RADIO_LINK_TIMEOUT value on the SACCH is received on the new channel after theinitialization, the counter shall be re-initialized with the new value.5.3BSS procedureThe criteria for determining radio link failure in the BSS should be based upon either the error rate on theuplink SACCH or on RXLEV/RXQUAL measurements of the MS. The exact criteria to be employed shallbe determined by the network operator.6Idle mode tasks6.1IntroductionWhilst in idle mode, an MS shall implement the cell selection and re-selection procedures described inGSM 03.22. These procedures make use of measurements and sub-procedures described in this clause.The procedures ensure that the MS is camped on a cell from which it can reliably decode downlink dataand with which it has a high probability of communications on the uplink. Once the MS is camped on acell, access to the network is allowed.This clause makes use of terms defined in GSM 03.22.The MS shall not use the discontinuous reception (DRX) mode of operation (i.e. powering itself downwhen it is not expecting paging messages from the network) while performing the cell selection algorithmdefined in GSM 03.22. However use of powering down is permitted at all other times in idle mode.SIST ETS 300 578 E9:2003
Page 12ETS 300 578 (GSM 05.08 version 4.18.3): August 1997For the purpose of cell selection and reselection, the MS shall be capable of detecting and synchronizingto a BCCH carrier and read the BCCH data at reference sensitivity level and reference interference levelsas specified in GSM 05.05. An MS in idle mode shall always fulfil the performance requirement specifiedin GSM 05.05 at levels down to reference sensitivity level or reference interference level. The allowederror rates (see TS GSM 05.05) might impact the cell selection and reselection procedure, e.g. trigger cellreselection. Moreover, one consequence of the allowed error rates is that in the case of no frequencyhopping and a TU3 (TU1.5 for DCS 1 800) propagation profile it can not be expected that an MS willrespond to paging unless the received level is 2 dB higher than the specified reference level.For the purposes of cell selection and reselection, the MS is required to maintain an average of receivedsignal strengths for all monitored frequencies. These quantities termed the "receive level averages", shallbe unweighted averages of the received signal strengths measured in dBm. The accuracy of the signalstrength measurements for idle mode tasks shall be the same as for radio link measurements (seesubclause 8.1.2).The times given in subclauses 6.2, 6.3 and 6.6 refer to internal processes in the MS required to ensurethat the MS camps as quickly as possible to the most appropriate cell.For the cell selection, the MS shall be able to select the correct (fourth strongest) cell and be able torespond to paging on that cell within 30 seconds of switch on, when the three strongest cells are notsuitable. This assumes a valid SIM with PIN disabled and ideal radio conditions.The tolerance on all the timing requirements in clause 6 is ±10 %, except for PENALTY_TIME where it is±2 s.6.2Measurements for normal cell selectionThe measurements of this clause shall be performed by an MS which has no prior knowledge of whichGSM or DCS 1 800 RF channels are BCCH carriers.The MS shall search all RF channels in the system (124 for P-GSM, 174 for E-GSM and 374 forDCS 1 800), take readings of received RF signal strength on each RF channel, and calculate the receivedlevel average for each. The averaging is based on at least f
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