XDfePrach_DDCCfg - 2.0 English

RFSoC DFE PRACH LogiCORE IP Product Guide (PG391)

Document ID
PG391
Release Date
2024-05-30
Version
2.0 English
Decimator Config.

Declaration

typedef struct
{
  u32 DecimationRate;
  u32 UserSCS;
  u32 RachGain[6];
} XDfePrach_DDCCfg;
Table 1. Structure XDfePrach_DDCCfg Member Description
Member Description
DecimationRate [0,1,2,3,4,8,9,10,11] Decimation Rate required to go from 30.72MS/s to the RACH sample rate:
  • 0: 1x decimation(not allowed when XDfePrach_CarrierCfg.CCRate==0)
  • 1: 2x decimation
  • 2: 4x decimation
  • 3: 8x decimation(not allowed when XDfePrach_CarrierCfg.CCRate==3)
  • 4: 16x decimation(not allowed when XDfePrach_CarrierCfg.CCRate==3 or XDfePrach_CarrierCfg.CCRate==2)
  • 8: 3x decimation
  • 9: 6x decimation
  • 10: 12x decimation(not allowed when XDfePrach_CarrierCfg.CCRate==3)
  • 11: 24x decimation(not allowed when XDfePrach_CarrierCfg.CCRate==3 or XDfePrach_CarrierCfg.CCRate==2)
UserSCS [0-4,12-15] SubCarrier spacing of the RACH transmission this DDC is decimating and set by user.

Required to determine phase increment:

  • 0: 15KHz spacing
  • 1: 30KHz spacing
  • 2: 60KHz spacing
  • 3: 120KHz spacing
  • 4: 240KHz spacing
  • 12: 1.25KHz spacing
  • 13: 3.75KHz spacing
  • 14: 5KHz spacing
  • 15: 7.5KHz spacing
RachGain [0-3] The array of [6] Decimation Gains.

Gain is applied to all active Decimation filters. Decimation filters are enabled depending upon the total decimation rate. The total_decimation_rate is the product of the decoded values of DecRate and XDfePrach_CarrierCfg.CCRate. Gain is applied on a per filter basis:

  • Always applies:
    • CCDecGain[0]=0: Gain of 0dB in last decimating filter
    • CCDecGain[0]=1: Gain of 6dB in last decimating filter
    • CCDecGain[0]=2: Gain of 12dB in last decimating filter
    • CCDecGain[0]=3: Gain of 18dB in last decimating filter
  • Only applies if total_decimation_rate = {4, 8, 16, 32, 6, 12, 24, 48, 96)
    • CCDecGain[1]=0: Gain of 0dB in fifth decimating filter
    • CCDecGain[1]=1: Gain of 6dB in fifth decimating filter
  • Only applies if total_decimation_rate = {8, 16, 32, 12, 24, 48, 96)
    • CCDecGain[2]=0: Gain of 0dB in fourth decimating filter
    • CCDecGain[2]=1: Gain of 6dB in fourth decimating filter
  • Only applies if total_decimation_rate = {16, 32, 24, 48, 96)
    • CCDecGain[3]=0: Gain of 0dB in third decimating filter
    • CCDecGain[3]=1: Gain of 6dB in third decimating filter
  • Only applies if total_decimation_rate = {32, 48, 96)
    • CCDecGain[4]=0: Gain of 0dB in second decimating filter
    • CCDecGain[4]=1: Gain of 6dB in second decimating filter
  • Only applies if total_decimation_rate = {96)
    • CCDecGain[5]=0: Gain of 0dB in first decimating filter
    • CCDecGain[5]=1: Gain of 6dB in first decimating filter