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FEATURE DESCRIPTION
Idle Mode Behavior
CMS 40 System
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Idle Mode Behavior Feature Description
MSC OSS
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BTS BTS BTS
155 16-FCDU 102 0171 Uae Rev B 1996-11-01 © 1996 Ericsson Inc. – All Rights Reserved
Idle Mode Behavior
The contents of this document are subject to revision without notice due tocontinued progress in methodology, design, and manufacturing.
Ericsson shall have no liability for any error or damages of any kindresulting from the use of this document.
This document is not intended for distribution as an individual document and should bemaintained as an integral part of the entire binder.
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Contents
1 Introduction 51.1 Reason for Reissue 5
2 Background 5
3 What Can Be Achieved 63.1 High Signal Strength When Accessing the System 63.2 Control of the Paging Load 63.3 Low Idle Mode Power Consumption 6
4 Technical Description 74.1 General 74.2 PCN Selection 8
4.2.1 General 84.2.2 Automatic Mode 94.2.3 Manual Mode 9
4.3 Cell Selection 94.3.1 General 94.3.2 Algorithm 10
4.4 Cell Reselection 124.4.1 Algorithm 124.4.2 Borders Between Location Areas 154.4.3 Limited Service State 15
4.5 Location Updating 164.5.1 General 164.5.2 Normal 164.5.3 Periodic Registration 164.5.4 IMSI Attach/Detach 17
4.6 Combinations of Control Channels 184.7 Paging 18
4.7.1 Paging Groups 184.7.2 Paging Strategies 204.7.3 Equal Access and Transit Network Selection in
the MSC/VLR and GMSC 204.8 System Information 214.9 Short Message Service Cell Broadcast 22
5 Engineering Guidelines 225.1 Recommendations 22
5.1.1 Paging Related Parameters 225.1.2 Location Area Related Parameters 235.1.3 C1 Cell Selection Criteria Related Parameters 245.1.4 C2 Reselection Criteria for GSM Phase 2 25
6 Parameters 266.1 Main Controlling Parameters 26
6.1.1 Parameters Transmitted on the SynchronizationChannel 26
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Idle Mode Behavior
6.1.2 Parameters Transmitted on the BroadcastControl Channel 26
6.2 Additional Parameters 276.2.1 Parameters Transmitted on the BCCH 276.2.2 Configuration Parameters 286.2.3 LATA Parameters 286.2.4 Paging Parameters Set in the MSC 29
6.3 Value Ranges and Default Values 29
7 Acronyms and Abbreviations 32
8 References 33
Appendix A: Paging Strategy Flow Chart 35
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Idle Mode Behavior
1 IntroductionThis document describes the CMS 40 Idle Mode Behavior feature. Thedocument includes the following information:
• Background
• Achievement description
• Technical description
• Engineering guidelines
• Parameters and parameter values
A Mobile Station (MS) which is on, but without a dedicated channelallocated, is in the idle mode. Tasks performed in the idle mode allow theMS to access the system from any location, and the system to reach theMS from any location in the network.
Idle mode behavior is managed by the MS and controlled by parametersreceived from the Base Transceiver Station (BTS) on the BroadcastControl Channel (BCCH). All main controlling parameters for idle modebehavior are transmitted on the BCCH carrier in each cell.
1.1 Reason for Reissue
This document is reissued to incorporate engineering guidelineinformation. These changes are identified with change bars.
2 BackgroundAt power-up, an MS immediately attempts to make contact with a PersonalCommunications Network (PCN). The particular PCN is selected eitherautomatically or manually. The MS looks for and selects a suitable cell,tunes to the control channel, listens to the system information messagestransmitted, and receives the available services provided. This selection isknown as “camping” on a cell. An MS in idle mode always attempts tocamp on the best cell, according to signal strength criteria. The MS alsoregisters its current location to the network for correct routing of incomingcalls.
The PCN selection mechanism, the cell selection and reselectionalgorithms, and the Location Updating (LU) procedure are core elementsof idle mode behavior. Their purpose is to ensure that an MS is camped ona cell that provides the highest probability of successful communication.
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Idle Mode Behavior
3 What Can Be Achieved
3.1 High Signal Strength When Accessing the System
The MS attempts to obtain the highest possible signal strength whenaccessing the system. This is achieved by the idle mode cell selection andreselection algorithms. These algorithms enable the MS to choose the mostsuitable cell to camp on, based on signal strength. A cell is suitable ifcertain criteria, listed in Section 4.3.2.3 on page 11, are satisfied. Campingon the most suitable cell provides the MS with a high probability of goodcommunication with the system.
The cell selection and reselection algorithms are governed by parametersettings. Using these parameters an operator can, on a cell-by-cell basis,make a specific cell more or less attractive to camp on for the MS.Therefore, the operator achieves similar behavior for MSs in idle mode asthose in active mode. Well-designed parameter settings for cell selectionand reselection in idle mode forces the MS to camp on the same cell that itwould choose in active mode.
3.2 Control of the Paging Load
In idle mode, the MS notifies the network whenever it changes locationarea by the LU procedure and keeps the network current as to its location.When the system receives an incoming call, the location area of the MS isknown, and the system does not have to page throughout the network,reducing the load on the system. If an MS does not respond on the firstpaging, the network can page a second time. See Section 4.7.2 on page 20for more information.
The MS notifies the network of its present status by the LU procedureperiodically, or when powered up or down, or both. This prevents thenetwork from performing unnecessary paging of MSs that have beenpowered down or left the coverage area, and avoids unnecessary loads onthe system. See Section 4.5.3 on page 16 and Section 4.5.4 on page 17 formore information.
3.3 Low Idle Mode Power Consumption
In idle mode, the MS periodically monitors the system information beingtransmitted in the current cell and performs measurements on neighboringcells (to see if a cell change should be initiated). Power consumptionduring idle mode is low and the MS spends the majority of the time in“sleep mode,” or in Discontinuous Reception (DRX).
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4 Technical Description
4.1 General
An MS in idle mode continuously performs measurements on the BCCHcarriers of serving and neighboring cells to determine the best cell to campon. If necessary, the MS registers its presence in the Location Area (LA)of the chosen cell by performing an LU.
Camping on a cell serves the following purposes:
• It allows the MS to receive information from the PCN.
• An MS can initiate a call by accessing the network on the RandomAccess Channel (RACH) of the cell on which it is camped.
• The PCN knows the location area of the cell in which the MS iscamped (unless the MS has entered a “limited service” state asdescribed in Section 4.4.3 on page 15) and can page the MS when anincoming call is received.
Idle mode tasks are subdivided into the following processes:
• PCN selection
• Cell selection
• Cell reselection
• Location updating
The relationship between these processes is illustrated in Figure 1 on page8.
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Idle Mode Behavior
LALUPCN
Location AreaLocation UpdatingPersonal Communications Network
Cell Selection
Cell Reselection
Location Updating
Cell & LAChanges
Initial Cell Selected
LU Responses
New LA
Periodic Registration
PCN Available
PCN Selected
PCN Selection
Service Indication to User
Indication to User
User Selection of PCN
Automatic/Manual Mode Selection
Figure 1. Overall Idle Mode Process
The concepts in the figure as well as the overall idle mode processes areexplained in Section 4.2 on page 8 through Section 4.5 on page 16.
4.2 PCN Selection
4.2.1 General
Under normal conditions, an MS operates in its home PCN. However, forexample, if the MS loses coverage, an alternate PCN can be selected. TheMS registers on a PCN if it finds a suitable cell to camp on, and if an LUis accepted. Note that successful registration is required for the MS toaccess the network. Performing LU is not necessary however, if stillresiding in the location area serviced by the PCN which was used prior toentering the inactive state.
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If national roaming is permitted, an MS can select and register in anotherPCN of its home country other than its home PCN. The MS subsequentlyperforms periodic attempts to return to its home PCN.
The following modes are used for PCN selection:
• Automatic mode uses a list of PCNs in order of priority.
• Manual mode delegates the decision to the user, only indicating whichPCNs are available.
4.2.2 Automatic Mode
In automatic mode, the MS selects a PCN in the following order (ifavailable and allowable), if a registered PCN does not exist or is notavailable:
• Home PCN
• PCNs stored in the Universal Identity Module (UIM) in priority order
• Other PCNs with received signal level above -85 dBm in random order
• All other PCNs in order of decreasing signal strength
4.2.3 Manual Mode
In manual mode, the MS indicates all available PCNs to the user. The userselects a PCN, causing the MS to initiate a registration. If the selectedPCN is not allowed, the user is required to select another PCN.
At any time, the user can request the MS to initiate reselection andregistration to an alternative, available PCN. This is performed by eitherautomatic or manual mode, depending on the user’s selection.
4.3 Cell Selection
4.3.1 General
The cell selection algorithm acquires the most suitable cell of the selectedPCN according to various requirements. If no cell is found and allavailable and allowed PCNs have been tried, the MS attempts to camp ona cell regardless of the PCN identity and enters a limited service state. Inthis state, the MS can only make emergency calls. If the MS losescoverage, it returns to the PCN selection state and selects another PCN.
The following strategies are used during cell selection:
• Normal cell selection is performed when no BCCH Allocation (BA) listis available.
• Stored list cell selection uses a stored BA list to speed up the cellselection procedure.
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4.3.2 Algorithm
4.3.2.1 Normal Cell Selection
During normal cell selection, the MS selects the most suitable cell to campon.
A cell is considered suitable if the following criteria are satisfied:
• The cell belongs to the selected PCN.
• The cell is not barred. When a cell is barred, camping by an MS in idlemode is not permitted. However, active MSs are allowed to handover toa barred cell.
• The cell does not belong to an LA listed as forbidden for nationalroaming.
• The cell selection criterion is fulfilled.
Note: National roaming is allowed only in certain LAs of a PCN otherthan the home PCN. LAs are stored in the UIM as forbidden fornational roaming after an LU attempt fails. This list is clearedwhen the MS is powered-off or the UIM is removed.
If the MS does not possess information on which BCCH carriers are usedin the network, it searchs all 299 Radio Frequency (RF) channels in thesystem, takes measurement samples of received RF signal strength, andcalculates the received average level for each. The averaging is based on aminimum of five samples for each RF carrier, spread evenly over a 3 to 5second period.
The MS then tunes to the carrier with the highest average signal strengthlevel and determines whether this carrier is a BCCH carrier by searchingfor the frequency correction burst sent on the Frequency CorrectionChannel (FCCH). When the MS verifies a BCCH carrier, it tunes to thatcarrier to read the Synchronization Channel (SCH) for theBSICparameter, and the BCCH for the BA list and system informationmessages. If the data is successfully decoded and the cell is suitable, theMS camps and performs all registrations necessary. If a minimum of the40 strongest Personal Communications System (PCS) 1900 RF channelsare tried and no suitable cells found, the MS selects another PCN accordingto the PCN selection procedure and continues to search suitable cells.
Cells can have two levels of priority; normal and low. Suitable lowpriority cells are camped on only if no other suitable cells of normalpriority are available. Cell priority is controlled by the Cell Bar Qualify
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Idle Mode Behavior
(CBQ) parameter, in conjunction with the Cell Bar Access(CB)parameter. For more information, see Table 1 on page 11.
Table 1. Behavior of the MS for Different Combinations of CBQ and CB
CBQ CB At Cell Selection At Cell Reselection
HIGH NO Normal Normal
HIGH YES Barred Barred
LOW NO Low Normal
LOW YES Low Normal
If the MS finds a cell that is part of the selected PCN but that is notsuitable, the MS uses the BA list obtained from that cell and searches onlythose BCCH carriers, expediting the procedure.
The BA list is defined by theMBCCHNOparameter and indicates to the MSwhich frequencies are monitored and measured both in idle and activemode. The BA list is sent to the MS, in idle mode, through systeminformation messages on the BCCH. Up to 32 BCCH carriers can bedefined by specifying their Absolute Radio Frequency Channel Number(ARFCN) using theMBCCHNOparameter. Note that this featuredescription discusses only the idle BA list. For a definition of separate listsfor idle and active mode, see theDouble BA ListsFeature Description.
4.3.2.2 Stored List Cell Selection
The MS may store the BA list in use by the selected PCN when the MSwas last active at power down. This information is stored in the UIM.
If an MS includes a stored BA list of the selected PCN, it performs thesame measurements as for normal cell selection. However, only the BCCHcarriers on the list are scanned. The BA list for a given PCN stored in theMS is reset and updated whenever the MS retrieves new BCCH data fromthat PCN. If a stored list cell selection is not successful, then normal cellselection takes place.
4.3.2.3 Cell Selection Criterion
In idle mode, the MS continuously calculates the cell selection quantityC1.The cell selection criterion is satisfied ifC1 > 0. Note that this quantity isalso referred to as the path loss criterion parameter in theJoint TechnicalCommittee (JTC) Specifications. However, theC1-criterion is based onlyon signal strength and in this document, refers to cell selection quantity.
The quantityC1 is calculated in Equation 1 on page 11.
Equation 1:
C1 = (received signal level � ACCMIN)�max (CCHPWR� P; 0)
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Idle Mode Behavior
where:
ACCMIN is the minimum received signal level at theMS required for accessing the system
CCHPWR is the maximum transmitting power that anMS is allowed to use when accessing thesystem
P is the maximum output power of the MS,according to its class
An MS must measure a cell signal strength higher thanACCMINto accessthe system. A lowerACCMIN, yielding a lower requirement on signalstrength, results in more MSs camping on that cell. The risk of droppedcalls is also increased since MSs in areas of low signal strength are able toaccess the system. If the MS’s maximum possible output power,P, islower thanCCHPWR, the signal strength requirement increases by thedifference betweenP andCCHPWR. As a result, if the MS cannot reach themaximum allowed output power, higher downlink signal strength isrequired. Thus, theC1-criterion controls access for MSs that receive highenough signal strength for successful downlink communication, but are notable to transmit enough power for successful uplink communication. Whenthis scenario occurs, the result is that the cell is probably not designed forMSs of the participating class.
4.4 Cell Reselection
4.4.1 Algorithm
4.4.1.1 Cell Reselection Measurements
Upon successful cell selection, the MS initiates the cell reselection tasks.The MS continuously takes measurements on its neighboring cells,initiating cell reselection when necessary.
The MS monitors all neighboring BCCH carriers, (indicated by the BAlist) in addition to the BCCH carrier of the serving cell, detecting moresuitable cells for camping. A minimum of five received signal levelmeasurement samples are required for each defined neighboring cell and arunning average of the received signal level is maintained for each carrierin the BA list.
System information messages sent on BCCH are read every 30 seconds tomonitor changes in cell parameters. Additionally, the MS synchronizes tothe BCCH information every 5 minutes to read the parameters that affectcell reselection for the six strongest nonserving carriers on the BA list.
The MS decodes theBSIC parameter for each of the six strongestsurrounding cells every 30 seconds, to confirm monitoring of the samecells. TheBSIC parameter consists of two parts, the Network Color Code(NCC) and the Base Station Color Code(BCC) . If anotherBSIC is
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Idle Mode Behavior
detected, it is treated as a new carrier and its BCCH data is determined.The NCCPERMparameter tells the MS whichNCCto monitor in its currentcell. The carrier is ignored if a PCN color code is detected that is notallowed in accordance with theNCCPERMsetting in the BCCH data of theserving cell.
The MS only takes measurement samples when listening to its own paginggroup and stays in sleep mode the remainder of the time. See Section4.7.1 on page 18. Table 2 on page 13 summarizes how often theBSICand the BCCH data must be decoded for the serving cell and neighboringcells while in idle mode.
Table 2. Decoding of BSIC and BCCH Data
BSIC BCCH Data
Serving Cell - At least every 30 seconds
Six Neighbors At least every 30 seconds At least every 5 minutes
4.4.1.2 Cell Reselection Criteria
To optimize cell reselection for fast-moving MSs for example, in amicrocell environment, additional cell reselection parametersCRO, TO, andPT are broadcast on the BCCH of each cell. Before an MS can changecells, it reads the applicable offset in the cell reselection algorithm fromthe BCCH of the potential target cell.
The cell reselection algorithm consists of five different criteria. If any oneof the criteria is satisfied, a cell reselection occurs. The cell reselectionprocess employs the cell reselection quantityC2. Whenever a cellreselection criterion is satisfied, the MS changes to the cell with thehighestC2 value. Note that the cell reselection quantityC2 is valid onlyfor MSs that support the Global System for Mobile Communications(GSM) Phase 2. Phase 1 MSs useC1 for cell reselection.
C2 is calculated as follows:
For PT ≠ 31 C2 = C1 + CRO� TO �H (PT� T )
For PT = 31 C2 = C1 � CRO
where:
H (x) = 0 for x < 0
H (x) = 1 for x � 0
CROapplies an offset to theC2 reselection criterion for the cell.
The TO parameter applies a negative offset toC2 for the duration ofPTafter the timer has started for the cell. This tends to prevent fast-movingMSs from selecting the cell (as described in theJTC Specifications Volume7, Part 3.6).
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Idle Mode Behavior
PT is the duration for whichTOapplies. ThePT value of 31 is reserved tochange the sign ofCROand the value ofTO is ignored as indicated by theequation definingC2.
T is initiated from zero when the MS places the neighboring cell on thelist of the six strongest carriers.T is reset to zero whenever the cell is nolonger on the list.
In this case, the value ofTO is ignored.T is initiated from 0 when the MSplaces the neighboring cell on the list of the six strongest carriers and isreset to 0 whenever the cell is no longer on that list.
The MS continuously calculates the value ofC1 and C2 for the servingand neighboring cells. It reselects and camps on another cell if any of thefollowing criteria are satisfied:
• The serving cell becomes barred.
• The MS unsuccessfully tried to access the network the allowed numberof times, as defined by theMAXRETparameter.
• The MS detects a downlink signalling failure. For more information,see Section 4.4.1.3 on page 14.
• C1 for the serving cell falls below 0 for a period of 5 seconds,indicating that the path loss to the cell is too high and that the MSneeds to change cells.
• The value ofC2 for a nonserving cell exceeds the value ofC2 for theserving cell for a period of 5 seconds, indicating the appearance of abetter cell. However, if the new cell belongs to a different LA, a cellreselection hysteresis parameterCRHalso applies. For moreinformation, see Section 4.4.2 on page 15.
4.4.1.3 Downlink Signalling Failure Criterion
The downlink signalling failure criterion uses the downlink signallingfailure counter. The “leaky bucket” algorithm bases decisions onsuccessfully decoded paging messages. When the MS camps on a cell, thecounter is initialized to a value equal to the nearest integer to 90/N whereN is the multiframes parameterMFRMSfor that cell. Thereafter, when theMS attempts to decode a message on its paging subchannel and themessage is unsuccessfully decoded, the counter is decreased by 4,otherwise the counter is increased by 1. However, the counter is neverincreased beyond the nearest integer to 90/N. The MS attempts to decode amessage each time its paging subchannel is sent. When the counterreaches 0, a downlink signalling failure is declared. A downlink signallingfailure results in a cell reselection.
The downlink signalling failure counter is reinitiated to the value equal tothe nearest integer to 90/N each time the MS changes cells to camp on.The MFRMSparameter is mainly used in conjunction with paging groups.For more information, see Section 4.7.1 on page 18.
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4.4.2 Borders Between Location Areas
If the MS is moving in a border area between LAs, it can repeatedlychange between cells of different LAs. Each change of LA requires anLU, causing a heavy signalling load and increasing the risk of lost pagingmessages. To prevent this, a cell reselect hysteresis parameterCRHisused. A cell in a different LA is selected only if better in terms of thequantityC2, than all cells in the current location area by the value ofCRH.This situation is illustrated in Figure 2 on page 15. Note that the cellreselection quantityC2 is valid only for MSs that support GSM Phase 2.Phase 1 MSs useC1 for cell reselection.
Current LA
Nominal LA Border
C2 = 5 dBm
C2 = 4 dBm Different LA
C2 = 7 dBm
Actual LA Border
Camp on thisCell
dBdBmLA
DecibelDecibel relative to a milliwattLocation Area
CRH = 4 dB
Figure 2. Cell Reselect Hysteresis Near Location Borders
The CRHparameter is broadcast on the BCCH. Since the value ofCRHmay differ for each cell, theCRHparameter used is the one beingbroadcast by the current serving cell.
4.4.3 Limited Service State
There are several situations in which the MS is unable to obtain normalservice from a PCN, such as failure to find a suitable cell or no UIM
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Idle Mode Behavior
inserted in the MS. Additionally, certain responses to an LU such as “PCNnot allowed,” “illegal MS,” “illegal Mobile Equipment” (an MS with noUIM) or “International Mobile Subscriber Identity (IMSI) unknown in theHome Location Register (HLR)” result in the MS entering a limitedservice state. Under any of these conditions, the MS attempts to camp onan acceptable cell regardless of PCN identity, so that emergency calls canbe made. In the limited service state, the presence of the MS need not beknown to the PCN on whose cell it is camped. Cell reselection takes placenormally, except that a 0 dB value of the cell reselection hysteresisparameterCRHis used.
4.5 Location Updating
4.5.1 General
The network requires the location of the MS to accurately route incomingcalls. The MS regularly informs the network of its location by performingLUs.
The following are the types of LUs:
• Normal
• Periodic Registration
• IMSI Attach
The MS may inform the network when it enters an inactive state, or IMSIdetach.
4.5.2 Normal
Normal LU is initiated by the MS when it detects entrance into a new LA.The MS listens to the system information transmitted on the BCCH carrierfor the serving cell, and compares it with the stored broadcast LocationArea Identity (LAI). If the broadcast LAI differs from the stored LAI, anormal LU is initiated and the new LAI stored in the MS. If the LU fails,(for example, because of entering a forbidden LA) the MS either selectsanother cell or returns to the PCN selection state.
4.5.3 Periodic Registration
Periodic registration avoids unnecessary paging of an MS that has left thecoverage area or has run out of battery power.
When the MS listens to the system information on the BCCH carrier, it isinformed if periodic registration is used in that cell as well as how often itshould inform the network that it is still attached (reachable). This iscontrolled by theT3212 parameter, a timeout value broadcast to the MSin the system information messages.
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The periodic registration timer is implemented in the MS and is reinitiatedevery time the MS returns to idle mode after being in active mode. If achange in theT3212 parameter value occurs, for example, at a change ofa T3212 broadcast, the timer is reloaded so that the new time to expirewill be the old time to expire modulo new timeout value.
See the following example:
• Old time to expire = 5.6 decihours
• New T3212 = 3 decihours
The new time to expire is 5.6 mod 3 = 2.6 decihours.
If the newT3212 parameter value is 7 decihours, the following occurs:
• Old time to expire = 5.6 decihours
• New T3212 = 7
The new time to expire is 5.6 mod 7, which is equal to 5.6.
When changing the timer to a value greater than the old time to expirevalue, the MS keeps the old time to expire value. However, when the newtimer value is less than the remainder of the old timer, the timer is initiatedwith a new value between 0 and the new timeout value.
Because the old time to expire is different for each MS, this procedurecauses the MSs to reinitiate their timers to different values, minimizing therisk of a high peak load on the system due to too many LUs occurring atthe same time, following change of theT3212 parameter value.
4.5.4 IMSI Attach/Detach
An MS undertakes the IMSI attach/detach operation to indicate to thenetwork it has entered into an active/inactive state. At power up, an IMSIattach message is sent from the MS to the Mobile Services SwitchingCenter (MSC)/Visitor Location Register (VLR). At power down, an IMSIdetach message is sent. A flag is set in the VLR to indicate the presentstate of certain MSs, preventing unnecessary paging of powered off MSs.The ATT parameter, broadcasted by the serving cell in the systeminformation messages, informs the MS whether or not it is requested tosend a message to the system every time it is turned on or off.
The MS is marked as detached (implicit detach) by the network when nosuccessful contact between the MS and the network occurs for a timedetermined by theT3212 timeout value plus a guard period. A timescanning function in the MSC detects this and marks the MS as detached.
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4.6 Combinations of Control Channels
Only certain combinations of control channels are allowed. The followingtypes of BCCH are available specified with theBCCHTYPEparameter:
Noncombined BCCH and Common Control Channel (CCCH)
Combined BCCH, CCCH and Stand-Alone Dedicated ControlChannel/4 (SDCCH/4)
Combined[including a CellBroadcastChannel(CBCH)]
BCCH, CCCH, SDCCH/4 and CBCH (the CBCHreplaces SDCCH subchannel number 2)
Note that CCCH is a combination of Paging Channel (PCH), Access GrantChannel (AGCH) and RACH.
Four combination types for an SDCCH channel are as follows:
SDCCH/8 Each physical channel consists of eight SDCCHsubchannels, that is, eight MSs are given dedicatedchannels at the same time.
SDCCH/8(including aCBCH)
The CBCH subchannel replaces SDCCH subchannelnumber 2. Only seven MSs are given dedicatedchannels simultaneously.
SDCCH/4 This combination consists of four SDCCHsubchannels with BCCH and CCCH. Four MSs aregiven dedicated channels at the same time.
SDCCH/4(including aCBCH)
This combination consists of three SDCCHsubchannels, BCCH, CCCH, and a CBCH subchannel.The CBCH subchannel replaces SDCCH subchannelnumber 2. Three MSs are given dedicated channelssimultaneously.
The number of required SDCCH/8 is specified by theSDCCHparameter.The CBCH is defined by theCBCHparameter. Only one CBCH can bespecified, that is, either the channel combination SDCCH/4 including aCBCH or SDCCH/8 including a CBCH can be defined in a cell.
4.7 Paging
4.7.1 Paging Groups
After an MS tunes to the BCCH carrier and decodes the system informationdata, it performs an evaluation, (taking into account the IMSI number)determining to which paging group it belongs. The particular method bywhich an MS determines to which paging group it belongs, along withwhich particular CCCH block of the available blocks on the paging channelis monitored, is found in theJTC Specification Volume 1.2; Volume 2, Part1.5. All MSs listening to a particular paging block are defined as being in
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the same paging group. When no paging messages are transmitted to MSsin a particular paging group, dummy pagings are sent instead.
The MS stays in sleep mode, minimizing power consumption, until itspaging group occurs. Sleep mode is illustrated in Figure 3 on page 19.However, the MS still reads the BCCH data sent by the serving cell atleast every 30 seconds.
BC F PCHS TDMA
Broadcast Control ChannelCommon Control ChannelFrequency Correction ChannelPaging ChannelSynchronization ChannelTime Division Multiple Access
BCCH + CCCH (Downlink)
BF C F C C
7 0 1 2 3 4 5 6 7 0 1 2 3 4 5
TDMA Frames
7 0 1
}Sleep Mode
Listening to PCH
Listening to PCH
Listening to PCH
Sleep Mode
Measuring on Neighbors
Measuring on Neighbors
Paging Group
S S
Figure 3. Idle Mode Measurements During Own Paging Group
The CCCH blocks are also used to send access grant messages on theAGCH to the MS. The structure of the CCCH regarding paging messagesand access grant messages is controlled by theAGBLKandMFRMSparameters.
In each downlink noncombined BCCH 51 frame multiframe, there are ninedifferent CCCH blocks. In the combined BCCH/SDCCH there are threedifferent CCCH blocks.AGBLKparameter is the number of reservedCCCH blocks for the AGCH. The remaining CCCH blocks (9-AGBLK, fornoncombined BCCH and 3-AGBLK, for combined BCCH) are used asPCH. Access grant messages are given priority over paging messages evenif no CCCH blocks are reserved for the AGCH, whenAGBLK= 0.
Together withAGBLK, MFRMSindicates how many different paginggroups that exist. TheMFRMSparameter is the multiframe period and
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defines the transmission interval of paging messages to the same paginggroup. More paging groups result in more paging capacity. However, aspecific paging group then appears less frequently, making call setup timesfor MS-terminating calls longer.
For example, if the number of CCCH blocks within a multiframe is 9 andAGBLKis set to 0, there are 9 different paging groups within a 51 framemultiframe. If MFRMSis set to 5, there will be5 � 9 = 45 different paginggroups, spread over 5 multiframes.MFRMShas a maximum value of 9,resulting in 81 different paging groups.
4.7.2 Paging Strategies
The description of the paging parameters and the different pagingstrategies are only applicable to the Ericsson MSC, HLR, and VLR.
The MSC manages the paging procedure in CMS 40. Different pagingstrategies are possible, for example, not sending a second paging orsending the second paging as global paging. The operator controls thepaging procedure with parameter settings in the MSC.
Paging attempts, including both first and repeated attempts, are either localor global, depending on whether or not the LAI is stored in the VLR. Formore information, see Figure 4 on page 35. Local pagings are onlyperformed within one LA, whereas global pagings are performed within anentire MSC area. A second paging is initiated if no response from the MSis received before a first timer expires. ThePAGTIMEFRST1LAtimer isused for local pagings andPAGTIMEFRSTGLOBfor global pagings.
If the first paging was a local, thePAGREP1LAparameter defines whetheror not a second paging is initiated and, if it is local or global. After thesecond paging is sent, the MSC waits for thePAGTIMEREP1LAtimer,indicating a local second paging, orPAGTIMEREPGLOB, indicating aglobal second paging, to expire before it concludes that the paging attemptwas unsuccessful.
If the first paging was a global paging and no response was receivedbefore the first timer expired, thePAGREPGLOBparameter defines whethera second global paging is initiated. If the second global paging is sent, theMSC waits for thePAGTIMEREPGLOBtimer to expire before it considersthe MS unreachable.
4.7.3 Equal Access and Transit Network Selection in the MSC/VLR and GMSC
The Equal Access and Transit Network Selection in the MSC/VLR andGateway Mobile Services Switching Center (GMSC) function providessubscribers with the option of choosing an interexchange carrier for callsacross a Local Access and Transport Area (LATA) boundary. It isimplemented in the MSC and may effect how paging is repeated.
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4.7.3.1 LATA Concept
The LATA is a geographical region corresponding to a charging area andmay consist of one or more LAs. Under the LATA concept, (which isindicated by theLATAUSEDparameter), it is possible to perform a secondpage within one LATA, using thePAGLATAandPAGREPCT1LAparameters.
4.8 System Information
System information messages, sent by the BTS, contain network datarequired by the MSs to appropriately communicate with the network.
For MSs in idle mode, system information message types 1, 2, 3, 4, 7, and8 are sent on the BCCH. The distribution of system information messages1, 7, and 8 are switched on and off and are controlled by theSIMSGandMSGDISTparameters. TheSIMSGparameter specifies the systeminformation messages, and theMSGDISTparameter specifies whether theyare turned on or off.
Note that system information types 5 and 6 are transmitted to MSs inactive mode and are therefore not addressed.
Table 3 on page 21, lists the contents of the different system informationmessages transmitted to MSs in idle mode. System information messagetypes 7 and 8 are only used as an extension mechanism for systeminformation message type 4. For more information, seeJTC SpecificationVolume 2, Part 2; Volume 2, Part 4.7.
Table 3. Contents of System Information Message Types 1 to 4
System Information Message Type
Contents 1 2 3 4
Cell Channel Description X
RACH Control Parameters X X X X
Neighbor Cells Description X
PCN Permitted X
Location Area Identity X X
Cell Identitiy X
Control Channel Description X
Cell Options X
Cell Selection Parameters X X
Radio Link Time-out X
CBCH Description X
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4.9 Short Message Service Cell Broadcast
Short Message Service Cell Broadcast (SMSCB) provides an operator withthe ability to distribute short messages to idle subscribers within the PCN.Before SMSCB data is distributed, the cell must be configured with aCBCH (see Section 4.6 on page 18), and the number of reserved accessgrant blocks,AGBLK, must be greater than 0. The SMSCB functiondistributes the messages to all idle MSs within a certain coverage area.Message data is entered as an SMSCB message on a cell-by-cell commandin the BSC. Each message contains up to 15 pages, with each pagecontaining up to 82 octets.
Messages may contain traffic reports, weather reports, or charginginformation. The frequency of distribution to the MSs is determined by therepetition interval. Reception of an SMSCB message by an MS is onlypossible in idle mode.
5 Engineering Guidelines
5.1 Recommendations
5.1.1 Paging Related Parameters
Table 4 on page 22 shows the relationship betweenMFRMS, AGBLK, thenumber of paging groups, and time between the transmission of eachpaging group.
Table 4. Relationship Between MFRMS and AGBLK
MFRMS
TimeBetween
Transmissionof EachPagingGroup
Number ofPagingGroups
CombinedBCCH
AGBLK = 0
Number ofPagingGroups
CombinedBCCH
AGBLK = 1
Number ofPagingGroups
NoncombinedBCCH
AGBLK = 0
Number ofPagingGroups
NoncombinedBCCH
AGBLK = 1
2 0.47 sec 6 4 18 16
3 0.71 sec 9 6 27 24
4 0.94 sec 12 8 36 32
5 1.18 sec 15 10 45 40
6 1.41 sec 18 12 54 48
7 1.65 sec 21 14 63 56
8 1.89 sec 24 16 72 64
9 2.12 sec 27 18 81 72
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5.1.1.1 MFRMS
The MFRMSparameter is used to determine the transmission interval ofpaging messages to paging groups. When used with theAGBLKparameter,MFRMSdetermines the number of paging groups that exist within a cell.For example, whenMFRMS = 9, the MS listens to its own paging groupevery ninth 51-frame multiframe, or approximately every 2.1 seconds(9 � 235:4 ms). The higher the value, the lower the power consumption inidle mode. However, the average call setup time for MS-terminated callsincreases slightly.
The MFRMSparameter’s impact on the MS battery consumption will varyfor different MSs. The trade off between lower battery consumption andshorter call setup time for MS-terminated calls should be based onoperator preference.
5.1.1.2 AGBLK
The AGBLKparameter determines how many of the nine noncombinedBCCH cells or 3 combined BCCH cells’ CCCH blocks are reserved forAccess Grant. No block reservation is required since Access Grant haspriority over paging in CMS 40. However, if System Information (SI) SI7and SI8 must be sent (C2 criteria related parameters supported by GSMPhase 2 MSs), or if the cell uses a noncombined BCCH with cellbroadcast,AGBLKcannot equal 0.
For Ericsson RBS2000 series BTSs,AGBLK = 0 andAGBLK = 1 aresupported. The recommended setting isAGBLK = 0.
5.1.2 Location Area Related Parameters
5.1.2.1 T3212
The T3212 parameter controls the periodic registration interval. Periodicregistration is required for an MS which has lost coverage to avoidunnecessary paging attempts. Additionally, periodic registration is requiredwhen an MS has the wrong status within the MSC/VLR regarding itscurrent LA and whether it is attached or detached. Periodic registration isa location update which is performed every 6 minutes whenT3212 = 1
and up to 25.5 hours whenT3212 = 255 on the signalling SDCCH. Thefrequency of LUs performed by the MSs affects the dimensioningrequirements for the SDCCH as well as the load in the BSC. For moreinformation, see theHierarchical Cell StructureFeature Description.
Recommended values forT3212 are between one hour (T3212 = 10) and4 hours (T3212 = 40). A lower value is not required since the MSsperform LUs for low battery power, change of LA, and power-down. Ahigher value will not have a large affect on the total number of LUs in thesystem.
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If implicit detach supervision is initiated, set the MSC parametersBTDMandGTDMin accordance with theT3212 parameter. TheBTDMparameteris the base time duration in minutes, which should be set equal toT3212 .The GTDMparameter is the guard time in minutes. Supervision time isequal to the sum ofBTDMandGTDM. These parameters are timers used toautomatically mark an MS as implicitly detached when the MS has noradio contact during a given period of time. Set the base time parameterlength equal to the LU time in the interworking BSC or the MS will beunexpectedly removed from the system before a periodic LU is performed.
5.1.2.2 CRH
The CRHparameter is used to prevent the MS from performing repeatedlocation area updates when close to an LA border.CRHis a hysteresisadded to the cell reselection algorithm for cells belonging to different LAs.If the CRHvalue is set too low, fluctuations in signal strength can lead to aping-pong effect, causing an undesired increase in the signalling load onthe SDCCH. IfCRHis set too high, the MS may camp on the wrong cell(not the strongest) too long when entering a new LA.
The default value ofCRH = 4 is recommended unless there are indicationsthat another setting will improve network performance. If a high numberof location area updates occur in an LA border cell, raise theCRHsetting.
5.1.2.3 ATT
The MS sends attach and detach information to the MSC/VLR at power-onand power-down. TheATT parameter notifies the MS if it is permitted toapply IMSI attach and detach. SetATT = YES so the system is alertedwhen the MS powers on or powers down. This prevents unnecessarypagings of the MS when it is no longer available.
5.1.3 C1 Cell Selection Criteria Related Parameters
C1 idle mode cell selection criteria is based upon signal strength.
5.1.3.1 ACCMIN
The ACCMINparameter is used when the MS calculates the cell selectionquantityC1 and determines the minimum received signal level at the MSrequired for accessing the system. A lowerACCMINvalue improvescoverage in idle mode but it can increase the number of call setup failures.Some MSs will experience problems attaching to the system expedientlyfollowing a temporary drop in signal strength belowACCMIN. MSs maydetach from the network even when sufficient signal strength for asuccessful call is present. SetACCMIN = �110. However, the trade offbetween idle mode coverage and the risk of increased numbers of callsetup failures can depend upon the operator’s preference.
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5.1.3.2 CCHPWR
The CCHPWRparameter dictates the maximum power level an MS useswhen accessing the system on the control channel.CCHPWRis included inthe C1 algorithm to limit the MSs’ capability to camp on a cell withoutadequate power to successfully communicate on the uplink. SetCCHPWR = MSTXPWR, the maximum allowed transmitted power in activemode.
5.1.4 C2 Reselection Criteria for GSM Phase 2
GSM Phase 2 usesC2, a more flexible cell reselection algorithm to controlcell reselection in idle mode.
5.1.4.1 CRO
CROis used to apply an offset to the cell reselection quantity for a cell.To control the traffic distribution between cells, CMS 40 allows theoperator to favor certain cells in active mode. An example is the L-criteria, which ranks the MSs according to path loss, offsets, andHierarchical Cell Structure (HCS). In some instances, a similarrequirement can occur in idle mode.CROencourages or discourages anMS from selecting the cell when camped on another cell in the system.
To not acquire equal traffic, if a cell has a large negative offset (KOFFSET)towards neighbors, the idle mode cell borders (according to theC1 criteria)will significantly differ from cell borders in active mode. Therefore, someMSs will camp on the wrong cell from a locating point of view. After callsetup, these MSs will either make an assignment to a better cell (providedthe feature is activated) or perform a handover shortly after the assignmentof a TCH. Too many assignments to a better cell may create congestion onthe SDCCH. Additionally, excessive handovers increase the signalling loadin the BSC. Proper setting of theCROparameter may reduce the numberof handovers and assignments to better cells.
5.1.4.2 Temporary Offset
The C2 criteria allows application of a temporary offset to a cell,preventing fast moving MSs from camping on a microcell. The temporarypenalty in idle mode uses the same principal as the temporary signalstrength penalty for lower layer cells in HCS. For more information, seethe Hierarchical Cell StructureFeature Description.
The temporary offset parameters areTO (size of offset) andPT (durationof offset). The penalty timer begins counting when the MS has the cell inits list of the six strongest BCCH carriers.
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6 Parameters
6.1 Main Controlling Parameters
6.1.1 Parameters Transmitted on the Synchronization Channel
BSIC is the Base Station Identity Code, defined cell-by-cell and expressedasNCC+ BCC.
6.1.2 Parameters Transmitted on the Broadcast Control Channel
The parameters that support idle mode correspond with the content of thesystem information messages as listed in Table 3 on page 21.
6.1.2.1 Neighbor Cells Description
MBCCHNOindicates the absolute RF channel number for BCCHfrequencies to be measured by MSs in a cell, for example, the BA list.MBCCHNOis defined on a cell-by-cell basis.
6.1.2.2 PCN Permitted
NCCPERMdefines the permittedNCCto be monitored.NCCPERMisdefined on a cell-by-cell basis.
6.1.2.3 Control Channel Description
BCCHTYPEis defined on a cell-by-cell basis and identifies the followingtype of BCCH used:
• COMBCombined indicates that the cell has a combined BCCH andSDCCH/4.
• COMBCCombined with CBCH indicates that the cell has a combinedBCCH and SDCCH/4 with a CBCH subchannel.
• NCOMBNot combined indicates that the cell does not have a combinedBCCH and SDCCH/4.
SDCCHis the required number of SDCCH/8.SDCCHis defined on acell-by-cell basis or by channel group.
MFRMSis the multiframes period and defines the period of transmissionfor paging messages to the same paging group.MFRMSis defined on acell-by-cell basis.
T3212 defines the timeout value that controls the periodic registrationprocedure.T3212 is defined on a cell-by-cell basis.
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6.1.2.4 Cell Selection Parameters
ACCMINis the minimum received signal level in dBm at the MS forpermission to access the system on a control channel.ACCMINis definedon a cell-by-cell basis.
CCHPWRis the maximum output power level in dBm an MS may usewhen accessing the system on a control channel.CCHPWRis defined on acell-by-cell basis.
CRHis the receiving signal strength hysteresis in dB for required cellreselection over a location area border.CRHis defined on a cell-by-cellbasis.
6.1.2.5 CBCH Description
CBCHis the cell broadcast channel and indicates whether or not a CBCHshall be included in one of the SDCCH subchannels for the cell or channelgroup. CBCHis defined on a cell-by-cell basis or by channel group.
6.2 Additional Parameters
6.2.1 Parameters Transmitted on the BCCH
6.2.1.1 RACH Control Parameters
CBdefines whether a certain cell is barred for access.CB is defined on acell-by-cell basis.
MAXRETis the maximum number of retransmissions an MS can performwhen accessing the system.MAXRETis defined on a cell-by-cell basis.
6.2.1.2 CCCH Parameters
ATT indicates if IMSI attach/detach is used in the cell.ATT is defined ona cell-by-cell basis.
AGBLKis the number of CCCH blocks reserved for the access grantchannel. The remaining CCCH blocks are used as paging channels.AGBLKis defined on a cell-by-cell basis.
6.2.1.3 Cell Selection Parameters
CBQcontrols the priority of a cell in conjunction withCB, see Table 1 onpage 11.CBQis defined on a cell-by-cell basis.
CROdefines an offset to encourage or discourage MSs to reselect that cell.CROis defined on a cell-by-cell basis.
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TOdefines a negative offset applied toCRO. TO is defined on a cell-by-cellbasis.
PT is the duration for which the temporary offset,TO, is applied.PT isdefined on a cell-by-cell basis.
6.2.2 Configuration Parameters
SIMSG is the system information BCCH message parameter.SIMSGspecifies which system information messages are turned on or off and isdefined on a cell-by-cell basis.
MSGDISTis the system information BCCH message distributionparameter.MSGDISTspecifies if the system information messagesspecified with theSIMSGparameter are turned on or off andMSGDISTisdefined on a cell-by-cell basis.
6.2.3 LATA Parameters
LATAUSEDdefines the usage of LATA administration and is only valid ifthe Equal Access and Transit Network Selection function is implementedin the MSC/VLR and GMSC. The following settings are available for theLATAUSEDparameter:
• 0 = LATA administration not used
• 1 = LATA administration used
PAGLATAindicates if LATA paging is used for MS-terminating calls. Thefollowing settings are available for thePAGLATAparameter:
• 0 = LATA paging not used
• 1 = LATA paging used
PAGREPCT1LAdefines how the paging in one location area is repeatedfollowing an initial local attempt. The parameter is only valid whenPAGLATA= 1. The following settings are available for thePAGREPCT1LAparameter:
• 0 = paging in one location area is not repeated
• 1 = paging in one location area is repeated with either a TemporaryMobile Subscriber Identity (TMSI) or an IMSI
• 2 = paging in one location area is repeated with an IMSI
• 3 = paging in one location area is repeated with a TMSI
PAGTIMEREPLATAdefines the time supervision for page response ofrepeated LATA paging. After expiration of the timer, no repeat paging forthis call is performed.
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6.2.4 Paging Parameters Set in the MSC
Parameters contained in this section are only applicable to the EricssonMSC, HLR, and VLR.
The following parameters are set in the MSC:
• PAGTIMEFRST1LAdefines the time supervision for the pagingresponse of the first paging attempt in one location area. Afterexpiration of this timer, the paging is repeated according to thePAGREP1LAparameter.
• PAGREP1LAdefines how the paging in one location area is repeated, ifthe first attempt was local. The following values are possible:
– 0 = paging in one location area is not repeated
– 1 = paging in one location area is repeated with either a TMSI or anIMSI
– 2 = paging in one location area is repeated with an IMSI
– 3 = paging in one location area is repeated as global paging with anIMSI
• PAGTIMEFRSTGLOBdefines the time supervision for the pagingresponse of the first global paging attempt. After expiration of thistimer, the paging is repeated according to thePAGREPGLOBparameter.
• PAGREPGLOBdefines how the global paging is repeated, if the firstpaging attempt was global. The following values are possible:
– 0 = global paging is not repeated
– 1 = global paging is repeated with an IMSI
• PAGTIMEREP1LAdefines the time supervision for the paging responseof repeated paging in one location area. After the expiration of thistimer, no new paging repetition for this call is performed.
• PAGTIMEREPGLOBdefines the time supervision for paging response ofrepeated global paging. After the expiration of this timer, no newpaging repetition for this call is performed.
6.3 Value Ranges and Default Values
Table 5 on page 29 lists theSCHidle mode parameters, theirrecommended values, default values, value ranges, and unit.
Table 5. SCH Parameter Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
BSIC - NCC: 0 to 7
BCC: 0 to 7
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Table 6 on page 30 lists theRACHidle mode control parameters, theirrecommended values, default values, value ranges, and unit.
Table 6. RACH Control Parameter Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
CB NO YES/NO
MAXRET 7 1, 2, 4, 7
Table 7 on page 30 lists the neighbor cell description parameters, theirrecommended values, default values, value ranges, and unit.
Table 7. Neighbor Cell Description Parameter Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
MBCCHNO - 512 to 810 ARFCN
Table 8 on page 30 lists the PCN parameters, their recommended values,default values, value ranges, and unit.
Table 8. PCN Parameter Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
NCCPERM - 0 to 7
Table 9 on page 30 lists the control channel description parameters, theirrecommended values, default values, value ranges, and unit.
Table 9. Control Channel Description Parameters Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
BCCHTYPE NCOMB COMB, COMBC,NCOMB
SDCCH 1 0 to 16
MFRMS 2 2 to 9
T3212 10 to 40 240 0 to 255 deci hours
(0 = infinite)
ATT YES NO YES/NO
AGBLK 0 1 0 to 7
0 to 2
Note: AGBLK holds a value of 0 to 7 for a noncombined BCCH and 0 to 2 for a BCCHcombined with any type of SDCCH. See Section 5.1.1.2 on page 23 for moreinformation.
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Table 10 on page 31 lists the cell selection parameters, their recommendedvalues, default values, value ranges, and unit.
Table 10. Cell Selection Parameters Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
ACCMIN -110 -110 -47 to -110 dBm
CCHPWR MSTXPWR
PCS 1900 - 4 to 30 in stepsof 2
dBm
CRH 4 4 0 to 14 in stepsof 2
dB
CBQ HIGH HIGH/LOW
CRO 0 0 to 63 Units of 2dB
TO 0 0 to 7 Units of 10dB
7 = infinite
PT 0 0 to 31 Units of 20sec
Note: PT = 31 indicates that the cell reselect offset is negated and temporary offset isignored.
Table 11 on page 31 lists theCBCHparameters, their recommended values,default values, value ranges, and unit.
Table 11. CBCH Parameter Default Values and Value Ranges
ParameterName
RecommendedValues
DefaultValue Value Range Unit
CBCH NO YES/NO
Note: When a CBCH is defined, the AGBLK must not be 0.
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Table 12 on page 32 lists the configuration parameters, their recommendedvalues, default values, value ranges, and unit.
Table 12. Configuration Parameters Default Values and Value Ranges
ParameterName
RecommendedValues Default Value Value Range Unit
SIMSG - 1, 7, 8
MSGDIST Type 1 = ON ON/OFF
Type 7 = OFF
Type 8 = OFF
Table 13 on page 32 lists the paging parameters, their recommendedvalues, default values, value ranges, and unit.
Table 13. Paging Parameters Default Values and Value Ranges
Parameter NameRecommended
ValuesDefaultValue
ValueRange Unit
PAGIMEFRST1LA 4 2 to 10 sec
PAGIMEFRSTGLOB 4 2 to 10 sec
PAGREP1LA 2 0, 1, 2, 3
PAGREPGLOB 0 0, 1
PAGTIMEREP1LA 7 2 to 10 sec
PAGTIMEREPGLOB 7 2 to 10 sec
LATAUSED 0 0, 1
PAGLATA 0 0, 1
PAGREPCT1LA 2 0 to 3
PAGTIMEREPLATA 7 2 to 10 sec
Note: The paging parameters apply only to Ericsson MSC, HLR, and VLR.
7 Acronyms and AbbreviationsAGCH Access Grant Channel
ARFCN Absolute Radio Frequency Channel NumberBA BCCH Allocation
BCCH Broadcast Control Channel
BSC Base Station Controller
BTS Base Transceiver Station
CBCH Cell Broadcast Channel
CCCH Common Control Channel
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dB Decibel
dBm Decibel relative to a milliwatt
DRX Discontinuous ReceptionFCCH Frequency Correction ChannelGMSC Gateway Mobile Services Switching CenterGSM Global System for Mobile CommunicationsHCS Hierarchical Cell Structure
HLR Home Location RegisterIMSI International Mobile Subscriber IdentityJTC Joint Technical Committee
LA Location Area
LAI Location Area IdentityLATA Local Access and Transport AreaLU Location Updatingms Millisecond
MS Mobile Station
MSC Mobile Services Switching CenterOSS Operations and Support SystemPCH Paging ChannelPCN Personal Communications Network
PCS Personal Communications SystemRACH Random Access Channel
RF Radio FrequencySCH Synchronization ChannelSDCCH Stand-Alone Dedicated Control Channel
sec Second
SI System InformationSMSCB Short Message Service Cell BroadcastTDMA Time Division Multiple AccessTMSI Temporary Mobile Subscriber IdentityUIM Universal Identity ModuleVLR Visitor Location Register
8 References
Other Related Documents
Double BA ListsFeature Description
Hierarchical Cell StructuresFeature Description
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JTC Specification Volume 1.2; Volume 2, Part 1.5
JTC Specification Volume 2, Part 2; Volume 2, Part 4.7
JTC Specification Volume 7, Part 3.6
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Appendix A
Appendix A
Paging Strategy Flow Chart
Local paging?
Paging is repeated according to PAGREP1LA.
Yes No
Start
SuccessfulAnswer? Answer?
IMSILALAIMSCTMSIVLR
International Mobile Subscriber IdentityLocation AreaLocation Area IdentityMobile Services Switching CenterTemporary Mobile Subscriber IdentityVisitor Location Register
Paging in MSC area;waiting for responsePAGTIMEFRSTGLOB.
Yes Yes
No
Paging is repeated according toPAGREPGLOB.
0 1
Paging in MSC area;waiting for responsePAGTIMEREPGLOB.
Paging in MSC area;waiting for response
PAGTIMEREPGLOB.
01 2 3Either TMSIor IMSI used. IMSI used. IMSI used.
No repeated paging.
Answer? Answer? Answer?
Successful
Unsuccessful
YesYes
No No No
No
Yes
VLR has an LAI(Normal Case).
LAI is missing.
Paging in one LA;waiting for responsePAGTIMEFRST1LA.
Paging in one LA;waiting for responsePAGTIMEFRST1LA.
Figure 4. Different Paging Strategies Flowchart
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