[handover] first functional handover implementation
With this commit, we can successfully hand over a channel from one cell to
another cell. We implement asynchronous intra-BSC (but inter-BTS) handover.
Changes:
* introduce new DHO log category
* extend rsl_chan_activate_lchan() with argument for HO reference
* introduce actual minimal handover decision making in handover_decision.c
* various fixes to bsc_handover_start() in handover_logic.c
diff --git a/openbsc/src/handover_logic.c b/openbsc/src/handover_logic.c
index d4a8884..99b3c01 100644
--- a/openbsc/src/handover_logic.c
+++ b/openbsc/src/handover_logic.c
@@ -85,23 +85,40 @@
{
struct gsm_lchan *new_lchan;
struct bsc_handover *ho;
+ static u_int8_t ho_ref;
int rc;
+ DEBUGP(DHO, "(old_lchan on BTS %u, new BTS %u): ",
+ old_lchan->ts->trx->bts->nr, bts->nr);
+
new_lchan = lchan_alloc(bts, old_lchan->type);
- if (!new_lchan)
+ if (!new_lchan) {
+ DEBUGPC(DHO, "No free channel\n");
return -ENOSPC;
+ }
ho = talloc_zero(NULL, struct bsc_handover);
if (!ho) {
+ DEBUGPC(DHO, "Out of Memory\n");
lchan_free(new_lchan);
return -ENOMEM;
}
ho->old_lchan = old_lchan;
ho->new_lchan = new_lchan;
+ ho->ho_ref = ho_ref++;
+
+ /* copy some parameters from old lchan */
+ memcpy(&new_lchan->encr, &old_lchan->encr, sizeof(new_lchan->encr));
+ new_lchan->ms_power = old_lchan->ms_power;
+ new_lchan->bs_power = old_lchan->bs_power;
+ new_lchan->rsl_cmode = old_lchan->rsl_cmode;
+ new_lchan->tch_mode = old_lchan->tch_mode;
/* FIXME: do we have a better idea of the timing advance? */
- rc = rsl_chan_activate_lchan(new_lchan, RSL_ACT_INTER_ASYNC, 0);
+ rc = rsl_chan_activate_lchan(new_lchan, RSL_ACT_INTER_ASYNC, 0,
+ ho->ho_ref);
if (rc < 0) {
+ DEBUGPC(DHO, "could not activate channel\n");
talloc_free(ho);
lchan_free(new_lchan);
return rc;
@@ -118,6 +135,8 @@
{
struct bsc_handover *ho = _ho;
+ DEBUGP(DHO, "HO T3103 expired\n");
+
lchan_free(ho->new_lchan);
llist_del(&ho->list);
talloc_free(ho);
@@ -129,6 +148,8 @@
struct bsc_handover *ho;
int rc;
+ DEBUGP(DHO, "handover activate ack, send HO Command\n");
+
ho = bsc_ho_by_new_lchan(new_lchan);
if (!ho)
return -ENODEV;
@@ -136,7 +157,7 @@
/* we can now send the 04.08 HANDOVER COMMAND to the MS
* using the old lchan */
- rc = gsm48_send_ho_cmd(ho->old_lchan, new_lchan, 0);
+ rc = gsm48_send_ho_cmd(ho->old_lchan, new_lchan, 0, ho->ho_ref);
/* start T3103. We can continue either with T3103 expiration,
* 04.08 HANDOVER COMPLETE or 04.08 HANDOVER FAIL */