Cc vn v Paging v SD assign fail

o Hong VD&O DepartmentPaging and SDCCH assign fail problem06-2009What is paging?Location management is the process by which the GSM network tracks the movement of mobile users throughout the PLMN down to Location Area (LA). Paging is process of locating the mobile user down to cell level for the purpose of establishing a Mobile-Terminated (MT) connection. Paging flow

How many types of paging message and its chracteristicsThree paging message types:Type 1 - 2 MSs using IMSI/TMSIType 2 - 3 MSs (1xIMSI, 2xTMSI)Type 3 - 4 MSs using TMSI onlyPaging message requires 4 bursts (1 CCCH block)Paging messages may be stored at BSSTransmitted on PCHIMSI comprises 8 octets containing the information of MNC, MCC, MSINIMSI = 456080131547785

TMSI is only 4 octets in size no need MNC, MCC. So, a paging message can store twice as many TMSIs as IMSIs. TMSI = 3C38A8A7=1010346151Paging CapacityPCH can be configured as combined or non-combined:Combined: both BCCH and SDCCH occupy the TS012 out of 51 slots per multiframe form 3 PCH/AGCH, each block consists of 4 slotsNon-combined: BCCH occupies TS0 and SDCCH occupies TS136 out of 51 slots per multiframe form 9 PCH/AGCH, each block consists of 4 slots

For combined BCCH:Example: if u reserved 1 block for AG, then u have 2 blocks for PCHIf u decide TMSI paging, I.e. 4 MS can be paged with 1 block of PCHThus; (number of PCH blocks*number of pages per block)/(51*one TDMA frame period);=(2*4) / (51*0.004615) = 3434 MS can be paged in a second (using TMSI paging)

Key Paging Parameters Initial Paging Request: Number of paging blocks available Paging message type Paging area (one LA, multiple LAs, global) Repeat Paging Requests: Type of repeat paging message Interval between repeat pages Maximum number of repeat paging attempts Maximum time before paging retries cease

Solution to improve PSRReducing "RACH Min. Access Level" Reducing "RXLEV-ACCESS-MIN" Increasing "MS Max RetransCoverage Effects on Paging Success Rate Paging Times and Paging Intervals IMSI Implicit Detact Timer of MSC LA Division Effects on Paging Success Rate What is SDDCH used for?

SD fail on Um interface because of bad quality, unbalance up-down link, co BCCH-BSIC

Action to solve PSR Increase paging time and paging interval at some LAC:Before: paging time 2, page interval 7s, 10sNow: paging time 3, page interval 6s, 6s, 6s.Change RACH min access level from -115dBm to -110dBm, Rx lev accsess min from -102dBm to -100dBmChange RET from 4 to 1Action to solve SAFR:Check parameter of Nokia and no difference from VNCheck counter and the method of formulas of SD fail is similar to Vit Nam. Turn off function of allocating dynamic SDCCH. But no helpDriving test at the cells have SD Assign Fail Rate cao. But dont see any thing unusualReset cell Optimize co BCCH-BSIC Change new card, reconnect jumper, feederENDTHANK YOUNo PAGING RESPONSE at Abis interface Check if there is PCH or AGCH overload due to centralized short message transmission or mass access bursts.Check the called MS or SIM in it.Check BTS by making test calls in a different cell.Check data configuration in BSCCheck whether the following parameters in the [System information table] are correctly configured: "BS_AG_BLKS_RES", "CCCH-CONF", "BS_PA_MFRMS", "Tx-integer," and "MS MAX retrans". Check the setting for "location updating period" in BSC and that in MSC Check radio signal coverage

No PAGING RESPONSE at A interfaceThrough signaling tracing at Abis interface, the BSC is detected that it has received an Establishment Indication (PAGING RESPONSE) message from the BTS but this message is not reported over interface A.No PAGING COMMAND at A interfaceChecking user data in VLR,Checking RA- or Cell-Related parameter settings in MSCNo PAGING COMMAND at Abis interfaceChecking if flow control is enabledCheck if the CGI information in BSC data configuration is consistent with the LAC information in the PAGING message over A interface

PCH

PCH may be used as AGCH but not vice-versaMOC requires AGCH and MTC requires PCHTypical network will have MOC higher than MTCStrategy: to dimension th=e AGCH to a smaller value and let the system organise the use of channelsParameter related to PCH:noOfMultiframesBetweenPaging (2 ... 9)It indicates the number of TDMA multiframes between transmission of paging message to the same paging sub-groupIt impacts on the MS battery life and MTC setup timeHigher value will save battery life but longer call setup time and vice versa. Recommended value is 5AGCH

Parameter related to AGCH:NumberOfBlocksForAccessGrant (0 ... 7)It defines the number of blocks reserved for access grant messages from the CCCH during the 51 TDMA frame (a multiframe)Recommended value is 1 for combined and 2 for non-combined configurationNote that if the AGCH is insufficient, PCH can be used as AGCH