diff options
| author | Philipp Maier <pmaier@sysmocom.de> | 2019-11-14 15:37:16 +0100 |
|---|---|---|
| committer | fixeria <axilirator@gmail.com> | 2019-11-20 13:35:02 +0000 |
| commit | 5c5ad3cb4afb131ce32cdc857899540c51aab604 (patch) | |
| tree | f541e63f67984dc5d2fc1c04408e8fc6bcb7dea9 | |
| parent | ae5e1d7110f1c87a0c4458cba47149b18f4ed2b6 (diff) | |
scheduler_trx.c: avoid division by zero when calculating BER
There is theoretical risk that when calculating the BER that a division
by zero occurrs. Lets add a check to avoid n_errors / n_bits_total when
n_bits_total is zero.
Change-Id: I1c0731b9a60be4b8c0c84b85b4403168120ceacd
Fixes: CID#205696
| -rw-r--r-- | src/osmo-bts-trx/loops.c | 10 | ||||
| -rw-r--r-- | src/osmo-bts-trx/loops.h | 3 | ||||
| -rw-r--r-- | src/osmo-bts-trx/scheduler_trx.c | 4 |
3 files changed, 13 insertions, 4 deletions
diff --git a/src/osmo-bts-trx/loops.c b/src/osmo-bts-trx/loops.c index e73d842c..47e9cf30 100644 --- a/src/osmo-bts-trx/loops.c +++ b/src/osmo-bts-trx/loops.c @@ -268,11 +268,19 @@ void trx_loop_sacch_clock(struct l1sched_trx *l1t, uint8_t chan_nr, } void trx_loop_amr_input(struct l1sched_trx *l1t, uint8_t chan_nr, - struct l1sched_chan_state *chan_state, float ber) + struct l1sched_chan_state *chan_state, + int n_errors, int n_bits_total) { struct gsm_bts_trx *trx = l1t->trx; struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)] .lchan[l1sap_chan2ss(chan_nr)]; + float ber; + + /* calculate BER (Bit Error Ratio) */ + if (n_bits_total == 0) + ber = 1.0; /* 100% BER */ + else + ber = (float) n_errors / (float) n_bits_total; /* check if loop is enabled */ if (!chan_state->amr_loop) diff --git a/src/osmo-bts-trx/loops.h b/src/osmo-bts-trx/loops.h index 78699031..978cb7ec 100644 --- a/src/osmo-bts-trx/loops.h +++ b/src/osmo-bts-trx/loops.h @@ -22,7 +22,8 @@ void trx_loop_sacch_clock(struct l1sched_trx *l1t, uint8_t chan_nr, struct l1sched_chan_state *chan_state); void trx_loop_amr_input(struct l1sched_trx *l1t, uint8_t chan_nr, - struct l1sched_chan_state *chan_state, float ber); + struct l1sched_chan_state *chan_state, + int n_errors, int n_bits_total); void trx_loop_amr_set(struct l1sched_chan_state *chan_state, int loop); diff --git a/src/osmo-bts-trx/scheduler_trx.c b/src/osmo-bts-trx/scheduler_trx.c index 9945b2ce..b54c35b5 100644 --- a/src/osmo-bts-trx/scheduler_trx.c +++ b/src/osmo-bts-trx/scheduler_trx.c @@ -1215,7 +1215,7 @@ int rx_tchf_fn(struct l1sched_trx *l1t, enum trx_chan_type chan, if (rc) trx_loop_amr_input(l1t, trx_chan_desc[chan].chan_nr | bi->tn, chan_state, - (float)n_errors/(float)n_bits_total); + n_errors, n_bits_total); amr = 2; /* we store tch_data + 2 header bytes */ /* only good speech frames get rtp header */ if (rc != GSM_MACBLOCK_LEN && rc >= 4) { @@ -1427,7 +1427,7 @@ int rx_tchh_fn(struct l1sched_trx *l1t, enum trx_chan_type chan, if (rc) trx_loop_amr_input(l1t, trx_chan_desc[chan].chan_nr | bi->tn, chan_state, - (float)n_errors/(float)n_bits_total); + n_errors, n_bits_total); amr = 2; /* we store tch_data + 2 two */ /* only good speech frames get rtp header */ if (rc != GSM_MACBLOCK_LEN && rc >= 4) { |