Channel AllocationSuitable for staff with P&O skill certificate IV or lowerIssued by GSM Network P&O Dept.The Secretes of GSM Algorithms

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Version Introduction

VersionDate WriterAssessorTranslatorAmendment RecordsV1.02009-03-27Ma JunhuaZheng HaoWang Hangyan This Resource Management Technique applies only to ZTE V3 system

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ContentsZTE Radio Resource Management TechniquesPrinciples of Radio Channel AllocationDynamic HR FunctionDynamic SDCCH FunctionChannel Allocation for Users in Different Priorities eMLPP Channel Allocation of Different Speech Codes

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I. ZTE Radio Resource Management TechniquesThe advantages of ZTE radio resource management techniquesChannels involved in the dynamic channel conversion functionHow to realize dynamic channel conversion

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1. The advantages of ZTE radio resource management techniquesFeatures iBSC introduces full dynamic radio techniques, at the premise of retaining static allocation of radio channel type. All channels (except PBCCH, BCCH, CCCH, PCCCH and SDCCH), such as TCH/FTCH/HPDTCH/F, etc could be inter-converted dynamically, in accordance with practical service needs. AdvantagesThe flexibility in using channels is increased greatly, and radio resource is used to the maximum.

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Default types of Dynamic TCH/F

Dynamic PDTCHDynamic TCH/HDynamic SDCCHThe default type of dynamic channel is TCH/F, which can realize dynamic inter-conversion with other channel types. The dynamic inter-conversion among other types needs to use TCH/F as a transition.2. Channels involved in the dynamic channel conversion function

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3.How to realize dynamic channel conversionThe default type of dynamically allocated radio channel is TCH/F. The implementation process of full dynamic radio depends mainly on channel activation and deactivation information between iBSC and BTS. In the CS or PS signaling flow before every service, iBSC will fill the channel type expected by this service in channel activation information, and after receiving it, BTS will activate the channel type as filled. On the contrary, after the service is ended, iBSC will fill type TCH/F in channel deactivation information when releasing channels, then, BTS will deactivate this channel as TCH/F.

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II. Principles of Radio Channel Allocation What are the priorities in radio channel allocationWhat is the general idea of TCH allocation algorithm What is the idea of PDTCH allocation algorithm

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1. What are the priorities in radio channel allocationHighLow

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2. What is the general idea of TCH allocation algorithm ? 1Allocate fixed channel before dynamic channelAllocate high priority channels before low priority channelsAllocate and use fixedly-allocated CS radio channel first until fixed allocation is used up, and then try allocating and assigning in dynamic channels. General idea12SFstatic TCHFDF: dynamic TCHFnext

Various Circumstances Channel Allocation Priority TRX with the highest priority and with no PS channel existed high

lowTRX with the highest priority and with PS channel existed TRX with the same TrxPrio value and relatively idle existing PS serviceTry allocation in TRX with lower TRX prioritychannel interference band is the best

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Timeslots useable to PS should be distributed as continuous as possible. 3General ideaWhen allocating and assigning CS channel within the scope of dynamic channel, the CS timeslots should be allocated in such a way that timeslots useable to PS in TRX are distributed as continuous as possible, and if there are many CS timeslots can meet this condition, the one near timeslot TS0 or TS7 should be picked in priority. After occupying 4 timeslots started from timeslot 0 or 7, there are still 4 continuous timeslots available to PS, guaranteeing the highest download speed. If 4 timeslots are occupied from the middle, there are only 2 groups of 2 continuous timeslots, which will inevitably affect PS download speed.

2. What is the general idea of TCH allocation algorithm2

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CS is prior to PS.4General idea When there is no idle timeslot in a cell, forced conversion between PS and CS channel will be implemented to newly initiated voice call, and it needs to decide which PS channel will be converted to CS channel. The strategy is : choose the channel with fewer users; choose the channel with lower bandwidth if users are the same in number; do not choose the channel amid PS channel of several continuous timeslots. PS channel is converted to CS channel forcefully. 2. What is the general idea of TCH allocation algorithm3

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3. What is the idea of PDTCH allocation algorithm? General ideaIn initial access, the same channel should be reused as much as possible by several mobile phones.To follow a step-by-step principle in PDTCH channel allocation, only one channel is allocated to initial access, and the same channel should be reused as much as possible by several mobile phones. If the sum of uplink and downlink LLC frame transmitted in this TBF exceeds a certain threshold, the user plane will initiate resource reassignment request, at this time, the decision about whether uplink or downlink first should be made according to the size of the uplink and downlink frame, and uplink should be adopted first if they are the same.

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III. Dynamic HR FunctionThe uses of dynamic HR functionAlgorithms used in dynamic HR functionParameters involved in dynamic HR functionThe process of dynamic HR conversion of TCH channel

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1.The Uses of Dynamic HR FunctionWhen a cell supports HR-FR conversion, channel types can be adjusted among HR-FR channels dynamically according to the real-time Cell TCH Load.When the traffic is not too busy, and is lower than real-time TCH load, the system will convert automatically some or all HR channels to FR channels to guarantee voice quality.Adjustment Strategy of Dynamic HR-FR ConversionDuring traffic peak period, when the real-time TCH load is exceeded, the system will convert automatically some or all FR channels to HR channels to increase network capacity. TCH Load Threshold

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2. Algorithms be used in dynamic HR functionin which,

represents the total number of timeslots in occupied state in a cell. Any service in timeslots indicates occupied state;

represents the total number of timeslots in the cell;

represents the total number of timeslots in blocked state in the cell. Algorithm of TCH load

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3. Parameters involved in dynamic HR functionDynamic HR parameters consist of BSC level and Cell level. When Cell Dynamic HR Parameter is set as Yes, the HR Application Threshold parameter at cell level will be enabled.If Dynamic HR Enable at BSC level is set as NO, the whole BSC does not support dynamic HR; if Use Cell Dynamic HR Parameter at Cell level is not enabled, HR threshold at BSC level will be taken as default.

LevelParameter NameEnglish AbbreviationValue Range & UnitDefault ValueBSCDynamic HR EnableDynaHREnableYes/NoNoHR Application ThresholdHRThs1100,%50CellUse Cell Dynamic HR ParameterUseCellDynHRParaYes/NoNoDynamic HR EnableDynaHREnableYes/NoNoHR Application ThresholdHRThs0100,%60

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4. The process of dynamic HR conversion of TCH channel1. The idle state of dynamically allocated radio channel is TCH/F 2. Cell TCH load reaches 50%.

3. Newly accessed MS is allocated to HR channel.

4. Dynamic channel is set as TCH/F after service is completed.5. Cell TCH load increases, and HR proportion increases.6. Cell TCH load is lower than 50%.

7. Newly accessed MS is allocated to FR channel.

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IV. Dynamic SDCCH Function

What is Dynamic SDCCH functionHow to realize dynamic conversion from TCH channel to SD channelWhich idle TCH channels will the system choose for conversionIn what situation will SDCCH channel convert back to TCH channelWhich parameters will be involved in dynamic SDCCH function

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1. What is dynamic SDCCH functionSDCCH Dynamic Allocation Function It means that when SDCCH channel in a cell is not enough, database will convert TCH to SDCCH dynamically .TCH/FSDCCHSDCCH dynamic allocation function includes:TCH->SDCCH conversion andSDCCH->TCH conversion

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2. How to realize dynamic conversion from TCH channel to SD channelConditions for TCH->SDCCH conversionIt should be allowed by configuration settings1Dynamic SDCCH configuration, in both Cell and BSC module, is allowed;The minimum value of SDCCH should be reached.2The number of idle SDCCH in the cell is less than the minimum value of SDCCH set in OMCRThe total number of idle TCH/F in the cell should meet certain requirements3 The total number of idle TCH/Fin a cell minus that of reserved TCH/F should be more than the minimum number of idle TCH set in OMCR or the total number of TRX in the cell.The total number of idle TCH in a sub-cell should be more than the minimum number of idle TCH.4The total number of idle TCH/F in the first sub-cell should be more than the minimum number of idle TCH in the cell set in OMCR.

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3. Which idle TCH channels will the system choose for conversionRequirements for frequency band should be met.1Choose the TCH that has the same frequency with BCCH TRX. If BCCH TRX is in P-GSM, extended frequency of E-GSM and R-GSM and TCH of 1800M should not be chosen. Static TCH/F first.2Choose static TCH/F before dynamic TCH/F.TCH channel with larger interference first.3Choose the TCH with the largest interference.Sub-cell first.4Choose the TCH in the first sub-cell.Strategies to choose idle TCH

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4. In what situation will SDCCH channel convert back to TCH channel? Algorithm of SDCCH->TCH ConversionThe number of idle SDCCH? 8+ MinSdcchS=MAX(S+12, TimeToTch)The initial value of S equals parameter TimeToTchS=S3Less thanmore thanWhether S is less than 0Trigger a conversion from SDCCH to TCH YesNoThe initial value of S is TimeToTch and could be set in iOMCR,

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5. Which parameters will be involved in dynamic SDCCH function?

LevelParameter NameEnglish AbbreviationValue Range & UnitDefault ValueBSC Can SDCCH Dynamic AllocationCanSdcchDyn No/YesNoScan SDCCH Cycle ScanSdcch 10-1000100ms 100Time Delay by Forced Release of TS TsRel 5-200100ms 10Maximum Time DelayMaxDelay 1200-2400100ms 1800Thresholds of TCH->SDCCH MinSdcch 2-6, 4Time Delay of SDCCH->TCH TimeToTch 0-24 0Cell Can SDCCH Dynamic AllocationCansdcchDyn No/Yes Yes

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V. Channel Allocation for Users in Different Prioritiers (eMLPP)eMLPP function and its use What network elements will be involved to enable eMLPP functionHow to define priorities of ZTE eMLPP How is the priority information transmitted to BSSHow to implement the function of eMLPPWhat parameters does eMLPP function include

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1. eMLPP function and its useeMLPP function in ZXG10 iBSC provides priority for high priority users, satisfying the services stipulated in eMLPPenhanced Multi-Level Precedence and Pre-emption serviceto realize differentiated network services.Its functions include mainlyQueuing, forced handover, and forced release according to user priorities.Allocate reserved channel for high priority users.Differentiate user priorities and make strategies to allocate channel.

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2. What network elements will be involved to enable eMLPP function?The realization of eMLPP function needs the interworking of HLR, MSC and BSS. MSBSSMSCHLRSubscription information eMLPPResource assignment requestPriorityassign channel

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3. How to define priorities of ZTE eMLPP?The subscription information corresponding to an MS is stored in HLR, which contains the highest priority property of the MS if it supports eMLPP function.eMLPP priority consists of 7 grades, in which priority A and B works only in one MSC, the actual effective ones range from 0 to 4, as detailed in Sheet 1.

Sheet 1 User-subscribed eMLPP priorities stored in HLRPriority DescriptionAthe highest priority, internal use onlyBinternal use only0user priority1user priority2user priority3user priority4user priority

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4. How is the Priority information transmitted to BSS? eMLPP property in HLR is reflected in MSC as radio resource priority BSS can identify, which is sent to BSS through ASSIGNMENT REQUEST information.

Table 2 Priority Parameters in ASSIGNMENT REQUEST MessageBit87654321AnnotationReservedPCIPriority LevelQAPVIRemarks: PCI: 1 means to preempt channel"; 0 means "not to preempt channel"Priority Level: 0 refers to "reserved channel," levels 1-14 are priority levels. 1 is the highest level, 15 is the reserved channel.QA:1 indicates to queue for resource application;" 0 indicates "not to queue for resource application" PVI: 1 means the resource can be preempted; 0 means the resource cannot be preempted.

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5. How to implement the function of eMLPP1The number of reserved channels can be allocated according to needs. The lowest user priority in which reserved channels could be occupied can also be set. Corresponding performance measurement item needs to be set to monitor the use status of reserved channels. According to parameter configuration, high priority users may occupy reserved channels first, if failed, they may occupy non-reserved channels; or vice verse. Occupy first non-reserved channel works better to ensure channel allocation to high priority users, but in this case, reserved channels will be idle more often, and resources will be used in lower efficiency.Implementation Methods of eMLPPProvide reserved channels for high priority users to use in assignment and handover. 1next

Emphasis: reserved channels cannot be converted to PS channel or SDCCH and TCH/H channel, and can only be occupied by high priority users who reached the priority as stipulated.

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When no channel can be allocated to high priority users, switch low priority users to neighbor cells to obtain channels (Forced Handover).Forced handover will exert little influence to low priority users, but it may occur that no neighbor cell available for their handover, or no usable channel offered in neighbor cell, resulting in handover implementation failure, etc. Thus, channel occupation of high priority users could not be guaranteed.Forcefully switch low priority users to the adjacent cell to release channels for high priority users. 25. How to implement the function of eMLPP2next

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Forced release may basically guarantee channels to high priority users, but it may leads to call drop of low priority users, thus, should be used carefully.The forced handover and forced release mentioned above are called preemption, and the principle is: high priority users with PCI may preempt the channels of low priority users with PVI.Forced release of low priority users to release channels for high priority users.35. How to implement the function of eMLPP3

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6. What parameters does eMLPP function include

LevelParameter Name English Abbreviation Value Range & UnitDefault valueBSC User PriorityPriThreshold 1 ~ 15 2Low User Priority LowPrioLelevl 1 ~ 15 1Reserved Channel First RsvChanFirst Yes/No Yes Percentage of eMLPP Reserved Channel EMLppThs% 0 ~ 100 0Cell Percentage of eMLPP Reserved Channel EmlppThs 0 ~ 100 0Use Cell eMLPP Reservation UseCellEmlppThs Yes/NoYesChannel Selection Method for Low Priority Users ChanSelectPrio_0 No changeNo changeFR first/ HR firstOnly FR/HR allowed Channel Selection Method for high Priority Users ChanSelectPrio_1 No changeNo change FR first/ HR firstOnly FR/HR allowed Queuing Allowed in AssignmentQueueInd_0 Yes/NoNo Queuing Allowed in Handover QueueInd_1 Yes/NoNo Preemption Allowed in AssignmentPreemptionInd_0 Yes/NoNo Preemption Allowed in Handover PreemptionInd_1 Yes/NoNo Preemption Allowed in AssignmentForcedHoInd_0 Yes/NoNo Preemption Allowed in Handover ForcedHoInd_1 Yes/NoNo

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VI. Channel Allocation Principles of Different Speech Codes

Which speech versions does ZTE supportWhich parameters can be used to adjust the allocation of speech versions

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1. Which speech versions does ZTE supportSpeech Versions Supported in ZTEGSMfull rate speech version 1FRGSMfull rate speech version 2 EFRGSM full rate speech version 3 AMR FRGSMhalf rate speech version 1HRGSM half rate speech version 3 AMR HR

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2. Which parameters can be used to adjust the allocation of speech versions

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