bssgp: Use measured leak rate for flow control

The leak rate sent to the SGSN does not reflect the current CS level,
lost frames, and control message overhead. So the SGSN cannot do
proper queue control under non-optimal conditions.

This commit computes the leak rate for the last flow control interval
by computing the maximum theoretical leak rate and basically
substracting control blocks, nacked blocks, and reduced block sizes
due to CS downgrade. By using this approach, the value will by more
stable on low load, where the value will tend to be near the value
derived from the configuration. On full load the transmitted value is
completely derived from the measurements.

Note that the MS default values are no adapted to the adapted BVC
leak rate, since a single MS which has a lower link quality would
otherwise be reducing the rate of another MS with good radio
conditions, which would not make much sense if they did not share any
PDCH.

Sponsored-by: On-Waves ehf

1 files changed, 3 insertions, 0 deletions

diff --git a/src/gprs_rlcmac_sched.cpp b/src/gprs_rlcmac_sched.cpp
index dedea269..ac1991df 100644
--- a/src/gprs_rlcmac_sched.cpp
+++ b/src/gprs_rlcmac_sched.cpp
@@ -332,6 +332,9 @@ int gprs_rlcmac_rcv_rts_block(struct gprs_rlcmac_bts *bts,
 	/* set USF */
 	msg->data[0] = (msg->data[0] & 0xf8) | usf;
 
+	/* Used to measure the leak rate, count all blocks */
+	gprs_bssgp_update_frames_sent();
+
 	/* send PDTCH/PACCH to L1 */
 	pcu_l1if_tx_pdtch(msg, trx, ts, arfcn, fn, block_nr);