Robert Schmidt
ec3642ea05
Delay compensation in SRS
Implementation of delay compensation in channel estimation based on SRS.
Testing, for example, with
sudo ./nr_ulsim -n1 -s50 -S50 -R51 -E 1 -W2 -y2 -z2 -d 10
we obtain the following logs.
LOGs with develop branch:
[NR_PHY] __lsRe__________lsIm__|____intRe_______intIm__|____noiRe_______noiIm__
[NR_PHY] ( 0) 687 -198 | 688 -198 | -1 -3
[NR_PHY] ( 1) 0 0 | 688 -196 | -1 -3
[NR_PHY] ( 2) 687 -198 | 644 -272 | -1 -1
[NR_PHY] ( 3) 0 0 | 600 -346 | -1 -1
[NR_PHY] ( 4) 513 -498 | 556 -422 | -1 -1
[NR_PHY] ( 5) 0 0 | 512 -496 | -1 -1
[NR_PHY] ( 6) 513 -498 | 440 -542 | -1 0
[NR_PHY] ( 7) 0 0 | 370 -588 | -1 0
[NR_PHY] ( 8) 226 -682 | 298 -634 | -1 -3
[NR_PHY] ( 9) 0 0 | 228 -680 | -1 -3
[NR_PHY] ( 10) 226 -682 | 140 -686 | -1 -1
[NR_PHY] ( 11) 0 0 | 52 -690 | -1 -1
intRe and intIm are the real and imaginary part of the interpolated
channel, respectively. These are the columns that matter. As we can see,
for example, in subcarrier 0 we have (688, -198), then in subcarrier 1
we have (688, -196), which is almost the same, and then in subcarrier 3
we have a jump (644, -272). This MR improves channel estimation by
taking delay into account. If we look at the following logs, we see that
the values vary more consistently from subcarrier to subcarrier.
LOGs with this MR:
[NR_PHY] __lsRe__________lsIm__|____intRe_______intIm__|____noiRe_______noiIm__
[NR_PHY] ( 0) 487 -139 | 490 -111 | -1 0
[NR_PHY] ( 1) 487 -139 | 483 -138 | -1 0
[NR_PHY] ( 2) 487 -139 | 465 -197 | 0 0
[NR_PHY] ( 3) 487 -139 | 436 -254 | 0 0
[NR_PHY] ( 4) 364 -353 | 402 -305 | -1 -1
[NR_PHY] ( 5) 364 -353 | 361 -352 | -1 -1
[NR_PHY] ( 6) 364 -353 | 317 -392 | -1 -1
[NR_PHY] ( 7) 364 -353 | 269 -426 | -1 -1
[NR_PHY] ( 8) 160 -481 | 214 -455 | 0 -1
[NR_PHY] ( 9) 160 -481 | 159 -478 | 0 -1
[NR_PHY] ( 10) 160 -481 | 98 -495 | -1 0
[NR_PHY] ( 11) 160 -481 | 39 -502 | -1 0
All the files in this directory, unless stated otherwise, are released under the terms of the main license of OpenAirInterface. See the file LICENSE in the top directory.