bts: Allow config of RACH control parameters tx-integer & max retrans
Tweaking theses can be useful especially tx-integer that influence
both the spread of rach attemps and the delay between two attemps.
Looking up GSM 04.08 3.3.1.1.2 & 10.5.2.29 can help determine good
values. The default are choosed with a wide spacing between attemps
(tx integer = 9 -> T=12 & S=217 (non-combined CCCH/SDCCH) or 115 (for
combined CCCH/SDCCH)). This alleviates the problem of responding to
several RACH attempts by a same MS, allocating several RF channels when
only 1 is needed.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/openbsc/src/gsm_data.c b/openbsc/src/gsm_data.c
index 12f439b..d6ebd92 100644
--- a/openbsc/src/gsm_data.c
+++ b/openbsc/src/gsm_data.c
@@ -175,6 +175,10 @@
bts->si_common.cell_alloc.data = bts->si_common.data.cell_alloc;
bts->si_common.cell_alloc.data_len =
sizeof(bts->si_common.data.cell_alloc);
+ bts->si_common.rach_control.re = 1; /* no re-establishment */
+ bts->si_common.rach_control.tx_integer = 9; /* 12 slots spread - 217/115 slots delay */
+ bts->si_common.rach_control.max_trans = 3; /* 7 retransmissions */
+ bts->si_common.rach_control.t2 = 4; /* no emergency calls */
for (i = 0; i < ARRAY_SIZE(bts->gprs.nsvc); i++) {
bts->gprs.nsvc[i].bts = bts;