From 958c66c6db20a7087fdff1627f107afe63549974 Mon Sep 17 00:00:00 2001
From: Raymond Knopp <raymond.knopp@eurecom.fr>
Date: Mon, 21 Nov 2016 12:06:22 +0800
Subject: [PATCH] handling of timing drift in rfdevice
---
targets/RT/USER/lte-enb.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/targets/RT/USER/lte-enb.c b/targets/RT/USER/lte-enb.c
index 8999a717ce..74e75bdc4d 100644
--- a/targets/RT/USER/lte-enb.c
+++ b/targets/RT/USER/lte-enb.c
@@ -843,6 +843,8 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
unsigned int rxs,txs;
int i;
int tx_sfoffset = 3;//(eNB->single_thread_flag == 1) ? 3 : 3;
+ openair0_timestamp old_ts;
+
if (proc->first_rx==0) {
// Transmit TX buffer based on timestamp from RX
@@ -876,6 +878,8 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_TRX_READ, 1 );
+ old_ts = proc->timestamp_rx;
+
rxs = eNB->rfdevice.trx_read_func(&eNB->rfdevice,
&(proc->timestamp_rx),
rxp,
@@ -883,13 +887,18 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
fp->nb_antennas_rx);
if (rxs != fp->samples_per_tti)
- printf("Asked for %d samples, got %d from USRP\n",fp->samples_per_tti,rxs);
+ LOG_E(PHY,"rx_rf: Asked for %d samples, got %d from USRP\n",fp->samples_per_tti,rxs);
VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_TRX_READ, 0 );
if (proc->first_rx == 1)
eNB->ts_offset = proc->timestamp_rx;
-
+ else {
+ if (proc->timestamp_rx - old_ts != fp->samples_per_tti) {
+ LOG_I(PHY,"rx_rf: rfdevice timing drift of %d samples\n",proc->timestamp_rx - old_ts);
+ eNB->ts_offset += (proc->timestamp_rx - old_ts);
+ }
+ }
proc->frame_rx = ((proc->timestamp_rx-eNB->ts_offset) / (fp->samples_per_tti*10))&1023;
proc->subframe_rx = ((proc->timestamp_rx-eNB->ts_offset) / fp->samples_per_tti)%10;
// synchronize first reception to frame 0 subframe 0
--
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