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LTE SYSTEM CONSTANTS INTRODUCTION

LTE SYSTEM CONSTANTS INTRODUCTION. System Constant. Low layer configuration out of MO parameters Service aware and performance sensitive System constant type : Node Internal parameters and RRC parameters

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LTE SYSTEM CONSTANTS INTRODUCTION

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  1. LTE SYSTEM CONSTANTS INTRODUCTION

  2. System Constant • Low layer configuration out of MO parameters • Service aware and performance sensitive • System constant type : Node Internal parameters and RRC parameters • System constant generally relate to : baseband module, L1 layer format , Mac layer scheduling ,etc

  3. WH Trail Project System Constant Configuration

  4. System Constant : 110 • preambleInitialReceivedTargetPower • Preamble initial received target power. Value in dBm. • Min: -120 Max: -90 Default: -110 • WH trail eNB : -96 Note: increase the preamble initial received target power will request random access success with a better radio environment , which will help to increase the UE attach/cell-selection success rate

  5. System Constant : 304 • dlMaxNrOfSePerTtiAndCell • An upper threshold on the maximum number of entities that the DL scheduler is allowed to schedule per cell in one TTI. • Min: 1 Max: 10 Default: 6 • WH Trail :2 Note: In the DL, no advantage when time multiplex or frequency multiplex .

  6. System Constant : 306 • ulMaxNrOfSePerTtiAndCell • An upper threshold on the maximum number of entities that the UL scheduler is allowed to schedule per cell in one TTI. • Min: 1 Max: 8 Default: 6 • WH Trail : 6 Note: Suggestion value is max value . In the UL , frequency multiplexing is a bit more efficient especially for cell edge . For more user in one TTI , every user get less RB , so UE can concentrate all power into less RB , then power per RB will be higher , finally the better SINR will be got for higher throughput .

  7. System Constant : 174 • periodicSrTimer • Timer used to simulate the reception of SR (Scheduling Request ) until we receive SRs from the UE • Min: 1 Max: 80 Default: 80 Unit: ms • WH Trail: 1 Note: Decrease the SR simulate time , help to decrease the time cost on scheduling which will help to decrease the E2E service delay .

  8. System Constant : 73 • initialBufferSizeDefault • Target TB size assigned in response to SR when srCause is default • Min: 2 Max: 2400 Default: 86 Unit: Byte • WH Trail: 86 Note: Manually set the SC value as the default , in another words this manually setting is no real effect . Smaller TB size caused shorter delay but cost more resource; larger TB size cause larger delay but cost less resource .

  9. System Constant : 637 • ulPreschedulingOn • A flag to enable/disable the prescheduling feature in the node. (0=disabled, 1=enabled) • Default: 0 • WH Trail: 0 Note: Pre-scheduling working without receiving scheduling request (SR) , it help to improve E2E service latency .

  10. System Constant : 25 • dlGinrForgettingFactorLarge • Time domain DL GINR filtering parameter for a large forgetting factor • Min: 1 Max: 100 Default: 75 Unit: % • WH Trail: 100 Note: Increase the forgetting factor to decrease the frequency of link adaption sensitivity . In some fast shorttime poor radio environment , ‘dull’ scheduling keep may keep the throughput more stable .

  11. System Constant : 26 • dlGinrForgettingFactorSmall • Time domain DL GINR filtering parameter for a small forgetting factor • Min: 1 Max: 100 Default: 70 Unit: 100% • WH Trail: 100 Note: Increase the forgetting factor to decrease the frequency of link adaption sensitivity . In some fast shorttime poor radio environment , ‘dull’ scheduling may keep the throughput more stable .

  12. System Constant : 28 • cqiReportTimerAperiodic • The timer value when a new periodic CQI report should be scheduled for a UE • Min: 0 Max: 255 Default: 10 Unit:ms • WH Trail: 100 Note: More CQI report cost more PUSCH resource , in trail system traffic load and radio environment is kept over a stable level , so most of CQI report carry the same information . So lengthen the CQI periodic time help to decrease the PUSCH load and release the resource for traffic

  13. System Constant : 872 • deltaPsdRs2Tx • Delta PSD in dB for the cell specific Reference Signal (CRS) relative to the reference PSD when using 2 Tx antenna ports. • Min: 0 Max: 2 Default: 2 (0=0dB;1=1.77dB;2=3dB) • WH Trail: 0 Note: Generally speaking , RS is 3dB higher . if it set to 0 , it will help to reduce the intra-LTE interference .

  14. System Constant Modify Example: • Modify the system constant acc ENodeBFunction=1,SystemConstants=1 writeSystConst 306 (SC) 6 ( value ) • Reset the system constant accENodeBFunction=1,SystemConstants=1 resetSystConst

  15. THANK YOU

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