maki/openairinterface5g
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Reset sched_ul_bytes on BSR to tend to overestimation

Browse Source 
On BSR reception, reset sched_ul_bytes. This change means that we assume
that no data is "in flight" for this UE at time of BSR reception, or,
put differently, that we overestimate the buffer size at UE (in the
worst case).

To illustrate this, consider the following traces before/after this
change.

Before this change: Upon BSR reception, the estimated BSR of the UE is
reset, but the gNB still accounts for data "in flight". It is visible
that the calculated buffer size (estimated - scheduled) quickly goes to
zero, and we don't use all resources, despite the buffer still being
full. The maximum application throughput in this run was ~220Mbps.

    [NR_MAC]   SHORT BSR at  773.19, est buf 300000
    [NR_MAC]   ULSCH/PUSCH:  774. 6 RNTI af8e UL sched  774. 9 PRB start  0:162 TDA  2 TBS 32797 est 300000 sched 152704 est BSR 147296 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774. 6 RNTI af8e UL sched  774.11 PRB start  0:162 TDA  4 TBS 7172 est 300000 sched 159876 est BSR 140124 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.10 RNTI af8e UL sched  774.12 PRB start  0:162 TDA  0 TBS 32797 est 292845 sched 185501 est BSR 107344 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.10 RNTI af8e UL sched  774.13 PRB start  0:162 TDA  2 TBS 32797 est 292845 sched 218298 est BSR  74547 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.11 RNTI af8e UL sched  774.14 PRB start  0:162 TDA  2 TBS 32797 est 260117 sched 218298 est BSR  41819 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.11 RNTI af8e UL sched  774.16 PRB start  0:162 TDA  4 TBS 7172 est 260117 sched 225470 est BSR  34647 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.15 RNTI af8e UL sched  774.17 PRB start  0: 35 TDA  0 TBS 7172 est 220236 sched 185501 est BSR  34735 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.15 RNTI af8e UL sched  774.18 PRB start  0:162 TDA  2 TBS 32797 est 220236 sched 218298 est BSR   1938 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  774.16 RNTI af8e UL sched  774.19 PRB start  0: 10 TDA  2 TBS 2017 est 187508 sched 187518 est BSR    -10 TPC 1
    [NR_MAC]   SHORT BSR at  774. 9, est buf 300000
    [NR_MAC]   ULSCH/PUSCH:  775. 0 RNTI af8e UL sched  775. 2 PRB start  0:162 TDA  0 TBS 32797 est 260117 sched 147549 est BSR 112568 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  775. 0 RNTI af8e UL sched  775. 3 PRB start  0:162 TDA  2 TBS 32797 est 260117 sched 180346 est BSR  79771 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  775. 1 RNTI af8e UL sched  775. 4 PRB start  0:162 TDA  2 TBS 32797 est 227389 sched 180346 est BSR  47043 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  775. 1 RNTI af8e UL sched  775. 6 PRB start  0:162 TDA  4 TBS 7172 est 227389 sched 187518 est BSR  39871 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  775. 5 RNTI af8e UL sched  775. 7 PRB start  0:162 TDA  0 TBS 32797 est 180353 sched 173174 est BSR   7179 TPC 1
    [NR_MAC]   ULSCH/PUSCH:  775. 5 RNTI af8e UL sched  775. 8 PRB start  0: 36 TDA  2 TBS 7298 est 180353 sched 180472 est BSR   -119 TPC 1

After this change: The gNB resets the number of bytes "in flight"
(sched). Thus, the calculated buffer is larger, and does not "run out"
before a new BSR arrives (which still indicates the maximum). The UE is
thus allocated all resources, but we might overestimate some resources.
The maximum application throughput in this run was ~300Mbps, limited by
MCS and not by estimated buffer size as in the previous case.

    [NR_MAC]   SHORT BSR at   43. 3, est buf 300000
    [NR_MAC]   ULSCH/PUSCH:   43.15 RNTI d3ea UL sched   43.17 PRB start  0:162 TDA  0 TBS 36897 est 263180 sched  36897 est BSR 226283 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   43.15 RNTI d3ea UL sched   43.18 PRB start  0:162 TDA  2 TBS 36897 est 263180 sched  73794 est BSR 189386 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   43.16 RNTI d3ea UL sched   43.19 PRB start 12:150 TDA  2 TBS 33822 est 263180 sched 107616 est BSR 155564 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   43.16 RNTI d3ea UL sched   44. 1 PRB start  0:162 TDA  4 TBS 7941 est 263180 sched 115557 est BSR 147623 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 1 RNTI d3ea UL sched   44. 3 PRB start  0:162 TDA  0 TBS 36897 est 173698 sched  25881 est BSR 147817 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 1 RNTI d3ea UL sched   44. 4 PRB start  0:162 TDA  2 TBS 36897 est 173698 sched  62778 est BSR 110920 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 1 RNTI d3ea UL sched   44. 6 PRB start  0:162 TDA  4 TBS 7941 est 173698 sched  70719 est BSR 102979 TPC 1
    [NR_MAC]   SHORT BSR at   43.13, est buf 300000
    [NR_MAC]   ULSCH/PUSCH:   44. 5 RNTI d3ea UL sched   44. 7 PRB start  0:162 TDA  0 TBS 36897 est 292079 sched  36897 est BSR 255182 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 5 RNTI d3ea UL sched   44. 8 PRB start  0:162 TDA  2 TBS 36897 est 292079 sched  73794 est BSR 218285 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 6 RNTI d3ea UL sched   44. 9 PRB start  0:162 TDA  2 TBS 36897 est 292079 sched 110691 est BSR 181388 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44. 6 RNTI d3ea UL sched   44.11 PRB start  0:162 TDA  4 TBS 7941 est 292079 sched 118632 est BSR 173447 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44.10 RNTI d3ea UL sched   44.12 PRB start  0:162 TDA  0 TBS 36897 est 213587 sched  39972 est BSR 173615 TPC 1
    [NR_MAC]   ULSCH/PUSCH:   44.10 RNTI d3ea UL sched   44.13 PRB start  0:162 TDA  2 TBS 36897 est 213587 sched  76869 est BSR 136718 TPC 1
This commit is contained in:
Robert Schmidt
2025-09-11 19:47:52 +02:00
parent 197492ae89
commit 7c9a7ab374
1 changed files with 2 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
+2
View File
@@ -595,6 +595,7 @@ static int nr_process_mac_pdu(instance_t module_idP,
/* Extract short BSR value */
ce_ptr = &pduP[mac_subheader_len];
sched_ctrl->estimated_ul_buffer = estimate_ul_buffer_short_bsr((NR_BSR_SHORT *)ce_ptr);
sched_ctrl->sched_ul_bytes = 0;
LOG_D(NR_MAC, "SHORT BSR at %4d.%2d, est buf %d\n", frameP, slot, sched_ctrl->estimated_ul_buffer);
break;
@@ -603,6 +604,7 @@ static int nr_process_mac_pdu(instance_t module_idP,
/* Extract long BSR value */
ce_ptr = &pduP[mac_subheader_len];
sched_ctrl->estimated_ul_buffer = estimate_ul_buffer_long_bsr((NR_BSR_LONG *)ce_ptr);
sched_ctrl->sched_ul_bytes = 0;
LOG_D(NR_MAC, "LONG BSR at %4d.%2d, estim buf %d\n", frameP, slot, sched_ctrl->estimated_ul_buffer);
break;