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DL-MMSE

Roberto Louro Magueta requested to merge develop-DL-improvements into develop

This MR is based on MR !2185 (merged)

  • Fix rxdataF_comp size in nr_rx_pdsch() function
  • Improvements in nr_dlsch_channel_compensation() function
  • Noise power estimation for DL at UE side
  • MMSE computation for DL at UE side

Theoretically, MMSE is better than ZF for low SNR, and then its performance converges as SNR increases. The results on the phy-simulators confirmed this. The gain for a frequency selective channel was not as great as for an AWGN channel. This probably happened because of the DCI, as the following LOGs appeared many times: [PHY] DCI false positive. Dropping DCI index 0. Mismatched bits: 284/864. Current DCI threshold: 205

Some results obtained in the phy-simulators were:

AWGN channel

sudo LD_LIBRARY_PATH=. ./nr_dlsim -n10000 -s4 -x2 -y2 -z2 -e2

  • ZF: Eff Throughput 50.47
  • MMSE: Eff Throughput 92.84

sudo LD_LIBRARY_PATH=. ./nr_dlsim -n10000 -s9.7 -x2 -y2 -z2

  • ZF: Eff Throughput 53.63
  • MMSE: Eff Throughput 94.01

sudo LD_LIBRARY_PATH=. ./nr_dlsim -n10000 -s16.6 -x2 -y2 -z2 -e16

  • ZF: Eff Throughput 78.88
  • MMSE: Eff Throughput 81.37

Frequency selective channel

sudo LD_LIBRARY_PATH=. ./nr_dlsim -n10000 -s7 -x2 -y2 -z2 -gR -e2

  • ZF: Eff Throughput 70.78
  • MMSE: Eff Throughput 82.81

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