Huawei WCDMA RNO Parameters Optimization

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Slide 1:

Parameter Optimization

Review :

Review Parameter optimization is an important step after RF Optimization . Parameter optimization improves service quality and utilization of network resources.

Review:

Review

Objectives:

Objectives Understand the process of parameter optimization Master the contents of parameter optimization Upon completion of this course, you can:

Contents:

Contents Parameter optimization procedure Parameter optimization contents

Parameter Optimization Process:

Parameter Optimization Process

Data Input and Find Problems:

Data Input and Find Problems Find problems from the input data, such as: Low success rate of call setup Low success rate of handover High rate of call drop

Verify Parameter Problems:

Verify Parameter Problems

Parameter Classification:

Parameter Classification Mobile Management Parameters Power Control Parameters Power Configuration Parameters Load Control Parameters Other Parameters

Determine Parameter Values :

Determine Parameter Values List the form for changing parameters (original parameter values vs. new parameter values) List MML commands for changing parameters Note: Maybe some tradeoff considerations need to be considered to assure the maximal improvement in the whole view such as “coverage and capacity”,“ fast and stable”, “improvement and risk”, “cost (or efforts) and gain”.

Impact:

Impact Impact on customer service and other networks Impact on OMC (efforts, maintenance)

Prepare Test Plan and Change Parameters:

Prepare Test Plan and Change Parameters Prepare test schedule, routes, tools and be ready to get Information. Change parameters and make records.

Slide 13:

Course Contents Parameter optimization Procedure Parameter optimization Contents

Parameter Optimization Contents:

Parameter Optimization Contents Mobile Management parameter optimization Power Control parameter optimization Power Configuration parameter optimization Load Control parameter optimization Note: There are too many parameters to introduce. Only some parameters about network optimization are mentioned here and maybe more parameters need to be added in the future.

Mobile Management Parameter Optimization:

Mobile Management Parameter Optimization Cell Selection & Reselection The changing of cell on which UE camped in idle mode or in Cell FACH, Cell PCH, URA PCH states. That assures UE camping the most suitable cell, receiving system information and establishing an RRC connection on a best serving cell. Handover The changing of cells with which UE connected in DCH mode. That assures seamless coverage and load balancing.

Cell Selection & Reselection Procedure:

Cell Selection & Reselection Procedure

Cell Selection Criteria (S Criteria):

Cell Selection Criteria (S Criteria) The cell selection criterion S is fulfilled when: Where: When a UE wants to select a UMTS cell, the cell must satisfy S criterion.

Cell Selection Parameters:

Cell Selection Parameters

Cell Re-selection Measure Condition :

Cell Re-selection Measure Condition Use Squal for FDD cells and Srxlev for TDD for Sx 1. If Sx > Sintrasearch, UE need not perform intra-frequency measurements. If Sx <= Sintrasearch, perform intra-frequency measurements. If Sintrasearch, is not sent for serving cell, perform intra-frequency measurements. 2. If Sx > Sintersearch, UE need not perform inter-frequency measurements. If Sx <= Sintersearch, perform inter-frequency measurements. If Sintersearch, is not sent for serving cell, perform inter-frequency measurements. 3. If Sx > SsearchRAT m , UE need not perform measurements on cells of RAT“ m". If Sx <= SsearchRAT m , perform measurements on cells of RAT "m". If SsearchRAT m, is not sent for serving cell, perform measurements on cells of RAT " m " .

Cell Reselection Criteria (R Criteria):

Cell Reselection Criteria (R Criteria) All cells should satisfy S Criteria. Select the Cell with the highest R value using the following method to compute. The cells shall be ranked according to the R criteria specified above, deriving Qmeas,n and Qmeas,s and calculating the R values using CPICH RSCP, P-CCPCH RSCP and the averaged received signal level for FDD, TDD and GSM cells, respectively. The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst1s is used for Qhysts to calculate Rs. If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above, but using the measurement quantity CPICH Ec/No for deriving the Qmeas,n and Qmeas,s and calculating the R values of the FDD cells. T he offset Qoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for Qhysts to calculate Rs. Following this second ranking, the UE shall perform cell re-selection to the best ranked FDD cell. In all cases, the UE shall reselect the new cell, only if the following conditions are met: - the new cell is better ranked than the serving cell during a time interval Treselection. - more than 1 second has elapsed since the UE camped on the current serving cell.

Slide 21:

Cell Reselection Parameters

Cell Reselection Parameters:

Cell Reselection Parameters

Cell Reselection from GSM to UMTS:

Cell Reselection from GSM to UMTS If the 3G Cell Reselection list includes UTRAN frequencies, the MS shall, at least every 5 s update the value RLA_C for the serving cell and each of the at least 6 strongest non-serving GSM cells. The MS shall then reselect a suitable (see TS 25.304) UTRAN cell if its measured RSCP value exceeds the value of RLA_C for the serving cell and all of the suitable (see 3GPP TS 03.22) non-serving GSM cells by the value XXX_Qoffset for a period of 5 seconds and, for FDD, the UTRAN cells measured Ec/No value is equal or greater than the value FDD_Qmin. In case of a cell reselection occurring within the previous 15 seconds, XXX_Qoffset is increased by 5 dB. where Ec/No and RSCP are the measured quantities. FDD_Qmin and XXX_Qoffset are broadcast on BCCH of the serving cell. XXX indicates other radio access technology/mode. Note:The parameters required to determine if the UTRAN cell is suitable are broadcast on BCCH of the UTRAN cell. An MS may start reselection towards the UTRAN cell before decoding the BCCH of the UTRAN cell, leading to a short interruption of service if the UTRAN cell is not suitable. Cell reselection to UTRAN shall not occur within 5 seconds after the MS has reselected a GSM cell from an UTRAN cell if a suitable GSM cell can be found. If more than one UTRAN cell fulfils the above criteria, the MS shall select the cell with the greatest RSCP value.

Cell Reselection Parameters from GSM to UMTS:

Cell Reselection Parameters from GSM to UMTS

Handover Procedure :

Handover Procedure Node B Node B Node B Intra-frequency cells Neighbor cells both from same NodeB or other NodeBs Measurement report Handover decision Measurement control Measurement and filtering Handover execution

Soft Handover Example:

Soft Handover Example

Soft Handover Procedure:

Soft Handover Procedure

Soft Handover Event – 1A:

Soft Handover Event – 1A 1A (add a cell in Active Set) MNew : the measurement result of the cell entering the reporting range. CIONew : the individual cell offset for the cell entering the reporting range if an individual cell offset is stored for that cell. Otherwise it is equal to 0. Mi : measurement result of a cell not forbidden to affect reporting range in the active set. NA : the number of cells not forbidden to affect reporting range in the current active set. MBest : the measurement result of the cell not forbidden to affect reporting range in the active set with the highest measurement result, not taking into account any cell individual offset. W : a parameter sent from UTRAN to UE. R1a : the reporting range constant. H1a : the hysteresis parameter for the event 1a.

Soft Handover Event – 1B:

Soft Handover Event – 1B 1B (Remove a cell from Active Set) MOld : the measurement result of the cell leaving the reporting range. CIOOld : the individual cell offset for the cell leaving the reporting range if an individual cell offset is stored for that cell. Otherwise it is equal to 0. Mi : measurement result of a cell not forbidden to affect reporting range in the active set. NA : the number of cells not forbidden to affect reporting range in the current active set. MBest : the measurement result of the cell not forbidden to affect reporting range in the active set with the lowest measurement result, not taking into account any cell individual offset. W : a parameter sent from UTRAN to UE. R1b : the reporting range constant. H1b : the hysteresis parameter for the event 1b.

Soft Handover Event – 1C:

Soft Handover Event – 1C 1C (a non-active primary CPICH becomes better than an active primary CPICH. If Active Set is not full, add the non-active cell into active set .Otherwise use the cell substitute the active cell.) MNew : the measurement result of the cell not included in the active set. CIONew : the individual cell offset for the cell becoming better than the cell in the active set if an individual cell offset is stored for that cell. Otherwise it is equal to 0. MInAS : the measurement result of the cell in the active set with the highest measurement result. MInAS : the measurement result of the cell in the active set with the lowest measurement result. CIOInAS : the individual cell offset for the cell in the active set that is becoming worse than the new cell. H1c : the hysteresis parameter for the event 1c.

Soft Handover Event – 1D:

Soft Handover Event – 1D 1D ( Change of best cell. If the chosen cell is not in Active Set, add the cell into Active Set and modify measurement control .Otherwise only modify measurement control. ) MNotBest : the measurement result of a cell not stored in "best cell" CIONotBest : the cell individual offset of a cell not stored in "best cell" . MBest: the measurement result of the cell stored in "best cell". CIOBest : the cell individual offset of a cell stored in "best cell" . H1d : the hysteresis parameter for the event 1d.

Soft Handover Parameters:

Soft Handover Parameters Parameter Name Description Default Setting IntraRelThdFor1A Relative thresholds of soft handover for Event 1A (R1a) 10, namely 5dB (step 0.5) IntraRelThdFor1B Relative thresholds of soft handover for Event 1B (R1b) 10, namely 5dB (step 0.5) Hystfor1A, Hystfor1B, Hystfor1C, Hystfor1D Soft handover hysteresis (H1x) 6,namely 3dB (step 0.5) for H1a . 8,namely 4dB(step 0.5) for H1b, H1c,H1d. CellIndividalOffset Cell CPICH measured value offset; the sum of this parameter value and the actually tested value is used for UE event estimation. (CIO) 0 WEIGHT Weighting factor, used to determine the relative threshold of soft handover according to the measured value of each cell in the active set. 0 TrigTime1A,TrigTime1B, TrigTime1C,TrigTime1D Soft handover time-to-trigger parameters (event time-to-trigger parameters. Only the equation are always satisfied during the trigger time, the event will be triggered). D640, namely 640ms . FilterCoef Filter coefficient of L3 intra-frequency measurement D5,namely 5

Inter-system Handover – CS Domain Procedure:

Inter-system Handover – CS Domain Procedure UE 1. RRC Connect Req 15. RAB Assign Req NODEB RNC 3G MSC BSS 2G MSC 2. RRC Setup Complete 3. Measure Control (measure ID 0x1 ) 4. Measure Control (measure ID 0x2 ) 5.Initial UE message(service request) 6.DL DT (Authentication Request) 7.UL DT (Authentication Response) 8.Common ID 9. Security Mode Command 10. Security Mode Command 11. Security Mode CMP 12. Security Mode CMP 13. UL DT(Setup) 14. DL DT(Call proceeding) 17.RL Recfg Ready 21 RAB Assign Resp 20 RB Setup Cmp 19 RB Setup 16.RL Recfg Prep 18.RL Recfg Commit 22. DL DT( Alerting ) 23. DL DT( Connect) 24. UL DT(Connect Ack) 26.RL Recfg Prep 28 PhyCh Reconfig 29.RL Recfg Comit 27.RL Recfg Ready 30 PhyCh Reconfig CMP 31 Meaure Control(ID3 ) 32Measure Report 33 Relocation Required 34 Relocation Command 35. HandoverFromUtranCommand 44 Iu Release Req 46 RL Del Resp 45 RL Del Req 47 Iu Release Complete 25 Measure Report(2D)

Inter-system Handover Measure :

Inter-system Handover Measure 1) Use Inter-frequency measurement reporting Event 2d, 2f to reflect the currently used frequency quality. Event 2d: The estimated quality of the currently used frequency is below a certain threshold. The variables in the formula are defined as follows: QUsed is the quality estimate of the used frequency. TUsed 2d is the absolute threshold that applies for the used frequency and event 2d. H2d is the hysteresis parameter for the event 2d. Event 2f: The estimated quality of the currently used frequency is above a certain threshold. The variables in the formula are defined as follows: QUsed is the quality estimate of the used frequency. TUsed 2f is the absolute threshold that applies for the used frequency and event 2f. H2f is the hysteresis parameter for the event 2f.

Inter-system Handover Measure:

Inter-system Handover Measure 2 ) When Received 2D reports ( that means the currently used frequency signal is poor ), RNC sends Measurement Control (ID3) to let UE begin to measure other system signal . UE will send measurement result reports periodically . When Received 2F reports (that means the currently used frequency signal is not poor), RNC sends Measurement Control (ID3,but different contents) to let UE stop measuring other system signal . 3) When received the periodical reports, RNC use the following formula to judge whether should handover UE to another system . Mother_RAT + CIO > Tother_RAT + H/2 Tother_RAT : the inter-system handover decision threshold; Mother_RAT : the inter-system (GSM RSSI) measurement result received by RNC; CIO: Cell Individual Offset, which is the inter-system cell setting offset; H : refers to hysteresis, If the formula is met, a trigger-timer called TimeToTrigForSysHo will be started, and a handover decision will be made when the timer times out; Note: if the inter-system quality satisfies the following condition before the timer times out: Mother_RAT + CIO < Tother_RAT - H/2 The timer will be stopped, and RNC will go on waiting to receive the next inter-system measurement report. The length of the trigger-timer is called time-to-trigger.

Inter-system Handover Parameters:

Inter-system Handover Parameters

Parameter Optimization Contents:

Parameter Optimization Contents Mobile Management parameter optimization Power Control parameter optimization Power Configuration parameter optimization Load Control parameter optimization

Power Control parameter optimization:

Power Control parameter optimization Power Control Characteristics Minimize the interference in the network, thus improve capacity and quality Maintain the link quality in uplink and downlink by adjusting the powers Mitigate the near far effect by providing minimum required power level for each connection Provides protection against shadowing and fast fading

Power Control Classification :

Power Control Classification Open Loop Power Control Open loop power control is used to determine UE’s initial uplink transmit power in PRACH and NodeB’s initial downlink transmit power in DPDCH. It is used to set initial power reference values for power control. Outer Loop power control Outer loop power control is used to maintain the quality of communication at the level of bearer service quality requirement, while using as low power as possible. Inner loop power control (also called fast closed loop power control) Inner loop power control is used to adjust UE’s uplink / NodeB’s downlink Dpch Power every one slot in accordance with TPC commands. Inner loop power control frequency is 1500Hz.

Open Loop Power Control - Uplink :

Open Loop Power Control - Uplink Preamble_Initial_Power = Primary CPICH TX power - CPICH_RSCP + UL interference + Constant Value where Primary CPICH TX power, UL interference and Constant Value are broadcasted in the System Information , and CPICH_RSCP is the measured value by UE 。

Open Loop Power Control - Downlink:

Open Loop Power Control - Downlink Where R is the user bit rate. W is the chip rate (3.84M). Pcpich is the Primary CPICH transmit power. Eb/Io is the downlink required Eb/Io value for a bearer service. (Ec/Io)cpich is measurement value reported by the UE. α is downlink cell orthogonal factor. Ptotal is the current cell’s carrier transmit power measured at the NodeB and reported to the RNC.

Open Loop Power Control Parameters:

Open Loop Power Control Parameters

Outer Loop Power Control:

Outer Loop Power Control Outer loop control is used to setting SirTarget (Signal to Interference Ratio Target) for inner loop power control. It is divided into uplink outer loop power control and downlink outer loop power control. The uplink outer loop power control is controlled by SRNC (serving RNC) for setting a target SIR for each UE. This target SIR is updated according to the estimated uplink quality (Block Error Ratio/ Bit Error Ratio). If UE is not in DTX ( Discontinuous Transmission) status (that means RNC can receive uplink traffic data), RNC will use Bler (Block Error Ratio) to compute SirTarget . Otherwise, RNC will use Ber (Bit Error Ratio) to compute SirTarget. The downlink outer loop power control is controlled by the UE receiver to converge to required link quality (BLER) set by the network (RNC) in downlink.

Outer Loop Power Control Parameters:

Outer Loop Power Control Parameters

Inner Loop Power Control:

Inner Loop Power Control The inner loop power control adjusts the UE or NodeB transmit power in order to keep the received signal-to-interference ratio (SIR) at a given SIR target, SIRtarget. It is also divided into uplink inner loop power control and downlink inner loop power control.

Uplink Inner Loop Power Control:

Uplink Inner Loop Power Control UTRAN behaviour The serving cells (cells in the active set) should estimate signal-to-interference ratio SIRest of the received uplink DPCH. The serving cells should then generate TPC commands and transmit the commands once per slot according to the following rule: if SIRest > SIRtarget then the TPC command to transmit is "0", while if SIRest < SIRtarget then the TPC command to transmit is "1". UE behaviour Upon reception of one or more TPC commands in a slot, the UE shall derive a single TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more than one is received in a slot. This is also valid when SSDT transmission is used in the downlink. Two algorithms shall be supported by the UE for deriving a TPC_cmd. Which of these two algorithms is used is determined by a UE-specific higher-layer parameter, "PowerControlAlgorithm", and is under the control of the UTRAN. If "PowerControlAlgorithm" indicates "algorithm1", then the layer 1 parameter PCA shall take the value 1 and if "PowerControlAlgorithm" indicates "algorithm2" then PCA shall take the value 2.

Uplink Inner Loop Power Control:

Uplink Inner Loop Power Control The step size DTPC is a layer 1 parameter which is derived from the UE-specific higher-layer parameter "TPC-StepSize" which is under the control of the UTRAN. If "TPC-StepSize" has the value "dB1", then the layer 1 parameter DTPC shall take the value 1 dB and if "TPC-StepSize" has the value "dB2", then DTPC shall take the value 2 dB. The parameter "TPC-StepSize" only applies to Algorithm 1 . For Algorithm 2 DTPC shall always take the value 1 dB. After deriving of the combined TPC command TPC_cmd using one of the two supported algorithms, the UE shall adjust the transmit power of the uplink DPCCH with a step of DDPCCH (in dB) which is given by: DDPCCH = DTPC  TPC_cmd.

Uplink Inner Loop Power Control:

Uplink Inner Loop Power Control Algorithm 1 for processing TPC commands When a UE is not in soft handover, only one TPC command will be received in each slot. In this case, the value of TPC_cmd shall be derived as follows: - If the received TPC command is equal to 0 then TPC_cmd for that slot is –1. - If the received TPC command is equal to 1, then TPC_cmd for that slot is Algorithm 2 for processing TPC commands When a UE is not in soft handover, only one TPC command will be received in each slot. In this case, the UE shall process received TPC commands on a 5-slot cycle, where the sets of 5 slots shall be aligned to the frame boundaries and there shall be no overlap between each set of 5 slots. The value of TPC_cmd shall be derived as follows: - For the first 4 slots of a set, TPC_cmd = 0. - For the fifth slot of a set, the UE uses hard decisions on each of the 5 received TPC commands as follows: If all 5 hard decisions within a set are 1 then TPC_cmd = 1 in the 5th slot. If all 5 hard decisions within a set are 0 then TPC_cmd = -1 in the 5th slot. Otherwise, TPC_cmd = 0 in the 5th slot.

Downlink Inner Loop Power Control:

Downlink Inner Loop Power Control UE behaviour The UE shall generate TPC commands to control the network transmit power and send them in the TPC field of the uplink DPCCH. The UE shall check the downlink power control mode (DPC_MODE) before generating the TPC command: If DPC_MODE = 0 : the UE sends a unique TPC command in each slot and the TPC command generated is transmitted in the first available TPC field in the uplink DPCCH; If DPC_MODE = 1 : the UE repeats the same TPC command over 3 slots and the new TPC command is transmitted such that there is a new command at the beginning of the frame. The DPC_MODE parameter is a UE specific parameter controlled by the UTRAN.

Downlink Inner Loop Power Control:

Downlink Inner Loop Power Control UTRAN behaviour Upon receiving the TPC commands UTRAN shall adjust its downlink DPCCH/DPDCH power accordingly. For DPC_MODE = 0, UTRAN shall estimate the transmitted TPC command TPCest to be 0 or 1, and shall update the power every slot. If DPC_MODE = 1, UTRAN shall estimate the transmitted TPC command TPCest over three slots to be 0 or 1, and shall update the power every three slots.

Inner Loop Power Control Parameters:

Inner Loop Power Control Parameters

Parameter Optimization Contents:

Parameter Optimization Contents Mobile Management parameter optimization Power Control parameter optimization Power Configuration parameter optimization Load Control parameter optimization

Physical Channels Types:

Physical Channels Types

Common Channel Parameters:

Common Channel Parameters All channels’ power refers to PCPICH power expect PCPICH.

Dedicated Channel Parameters:

Dedicated Channel Parameters Dedicated Channel Power refers to PCPICH Power.

Parameter Optimization Contents:

Parameter Optimization Contents Mobile Management parameter optimization Power Control parameter optimization Power Configuration parameter optimization Load Control parameter optimization

Load Control Parameter Optimization:

Load Control Parameter Optimization Call Admission Control (CAC) Call admission control is used to control cell’s load by admission/rejection request to assure a cell’s load under control. Dynamic Channel Configuration Control (DCCC) Dynamic Channel Configuration Control is used to dynamically change a connection’s load to improve cell resource utilization and control cell’s load.

Call Admission Control Procedure :

Call Admission Control Procedure

Call Admission Control Parameters:

Call Admission Control Parameters Different service type can be configured different threshold. That means leave some resources for important service ( or request), such as HO > Conversation > Other. Ul(Dl)TotolKThd is used when NodeB load report is not available . It uses equivalent 12.2k-voice users number method.

Dynamic Channel Configuration Control:

Dynamic Channel Configuration Control Dynamic channel configuration control (DCCC) aims to make full use of radio resource (codes, power, CE ) - Configured bandwidth is fixed with no DCCC - Configured bandwidth is changing with DCCC - Traffic rate Rate or band

DCCC Procedure:

DCCC Procedure Measurement report DCCC decision Traffic Volume measurement control UE and RNC Measurement DCCC execution

Traffic Volume Measurement:

Traffic Volume Measurement

DCCC Decision:

DCCC Decision 1) 4a event report -> increase bandwidth 4b event report -> decrease bandwidth 2) if current bandwidth <= DCCC threshold, do not decrease bandwidth

Dynamic Channel Configuration Control Parameters:

Dynamic Channel Configuration Control Parameters

Dynamic Channel Configuration Control Parameters:

Dynamic Channel Configuration Control Parameters

Summary:

Summary Parameter Optimization improves network quality and solves network problems. Parameter Optimization is a complicated procedure and needs parameter and algorithm knowledge. Parameter Optimization will be combined with other optimization activities making network better !

Slide 67:

Q & A ?

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