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-rw-r--r--src/libbsc/handover_decision.c325
1 files changed, 0 insertions, 325 deletions
diff --git a/src/libbsc/handover_decision.c b/src/libbsc/handover_decision.c
deleted file mode 100644
index 8d7e047b7..000000000
--- a/src/libbsc/handover_decision.c
+++ /dev/null
@@ -1,325 +0,0 @@
-/* Handover Decision making for Inter-BTS (Intra-BSC) Handover. This
- * only implements the handover algorithm/decision, but not execution
- * of it */
-
-/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
- *
- * All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-#include <stdlib.h>
-#include <errno.h>
-
-#include <osmocom/core/msgb.h>
-#include <openbsc/debug.h>
-#include <openbsc/gsm_data.h>
-#include <openbsc/meas_rep.h>
-#include <openbsc/signal.h>
-#include <osmocom/core/talloc.h>
-#include <openbsc/handover.h>
-#include <osmocom/gsm/gsm_utils.h>
-
-/* Get reference to a neighbor cell on a given BCCH ARFCN */
-static struct gsm_bts *gsm_bts_neighbor(const struct gsm_bts *bts,
- uint16_t arfcn, uint8_t bsic)
-{
- struct gsm_bts *neigh;
- /* FIXME: use some better heuristics here to determine which cell
- * using this ARFCN really is closest to the target cell. For
- * now we simply assume that each ARFCN will only be used by one
- * cell */
-
- llist_for_each_entry(neigh, &bts->network->bts_list, list) {
- /* FIXME: this is probably returning the same bts again!? */
- if (neigh->c0->arfcn == arfcn &&
- neigh->bsic == bsic)
- return neigh;
- }
-
- return NULL;
-}
-
-
-/* issue handover to a cell identified by ARFCN and BSIC */
-static int handover_to_arfcn_bsic(struct gsm_lchan *lchan,
- uint16_t arfcn, uint8_t bsic)
-{
- struct gsm_bts *new_bts;
-
- /* resolve the gsm_bts structure for the best neighbor */
- new_bts = gsm_bts_neighbor(lchan->ts->trx->bts, arfcn, bsic);
- if (!new_bts) {
- LOGP(DHO, LOGL_NOTICE, "unable to determine neighbor BTS "
- "for ARFCN %u BSIC %u ?!?\n", arfcn, bsic);
- return -EINVAL;
- }
-
- /* and actually try to handover to that cell */
- return bsc_handover_start(lchan, new_bts);
-}
-
-/* did we get a RXLEV for a given cell in the given report? */
-static int rxlev_for_cell_in_rep(struct gsm_meas_rep *mr,
- uint16_t arfcn, uint8_t bsic)
-{
- int i;
-
- for (i = 0; i < mr->num_cell; i++) {
- struct gsm_meas_rep_cell *mrc = &mr->cell[i];
-
- /* search for matching report */
- if (!(mrc->arfcn == arfcn && mrc->bsic == bsic))
- continue;
-
- mrc->flags |= MRC_F_PROCESSED;
- return mrc->rxlev;
- }
- return -ENODEV;
-}
-
-/* obtain averaged rxlev for given neighbor */
-static int neigh_meas_avg(struct neigh_meas_proc *nmp, int window)
-{
- unsigned int i, idx;
- int avg = 0;
-
- idx = calc_initial_idx(ARRAY_SIZE(nmp->rxlev),
- nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev),
- window);
-
- for (i = 0; i < window; i++) {
- int j = (idx+i) % ARRAY_SIZE(nmp->rxlev);
-
- avg += nmp->rxlev[j];
- }
-
- return avg / window;
-}
-
-/* find empty or evict bad neighbor */
-static struct neigh_meas_proc *find_evict_neigh(struct gsm_lchan *lchan)
-{
- int j, worst = 999999;
- struct neigh_meas_proc *nmp_worst = NULL;
-
- /* first try to find an empty/unused slot */
- for (j = 0; j < ARRAY_SIZE(lchan->neigh_meas); j++) {
- struct neigh_meas_proc *nmp = &lchan->neigh_meas[j];
- if (!nmp->arfcn)
- return nmp;
- }
-
- /* no empty slot found. evict worst neighbor from list */
- for (j = 0; j < ARRAY_SIZE(lchan->neigh_meas); j++) {
- struct neigh_meas_proc *nmp = &lchan->neigh_meas[j];
- int avg = neigh_meas_avg(nmp, MAX_WIN_NEIGH_AVG);
- if (!nmp_worst || avg < worst) {
- worst = avg;
- nmp_worst = nmp;
- }
- }
-
- return nmp_worst;
-}
-
-/* process neighbor cell measurement reports */
-static void process_meas_neigh(struct gsm_meas_rep *mr)
-{
- int i, j, idx;
-
- /* for each reported cell, try to update global state */
- for (j = 0; j < ARRAY_SIZE(mr->lchan->neigh_meas); j++) {
- struct neigh_meas_proc *nmp = &mr->lchan->neigh_meas[j];
- unsigned int idx;
- int rxlev;
-
- /* skip unused entries */
- if (!nmp->arfcn)
- continue;
-
- rxlev = rxlev_for_cell_in_rep(mr, nmp->arfcn, nmp->bsic);
- idx = nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev);
- if (rxlev >= 0) {
- nmp->rxlev[idx] = rxlev;
- nmp->last_seen_nr = mr->nr;
- } else
- nmp->rxlev[idx] = 0;
- nmp->rxlev_cnt++;
- }
-
- /* iterate over list of reported cells, check if we did not
- * process all of them */
- for (i = 0; i < mr->num_cell; i++) {
- struct gsm_meas_rep_cell *mrc = &mr->cell[i];
- struct neigh_meas_proc *nmp;
-
- if (mrc->flags & MRC_F_PROCESSED)
- continue;
-
- nmp = find_evict_neigh(mr->lchan);
-
- nmp->arfcn = mrc->arfcn;
- nmp->bsic = mrc->bsic;
-
- idx = nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev);
- nmp->rxlev[idx] = mrc->rxlev;
- nmp->rxlev_cnt++;
- nmp->last_seen_nr = mr->nr;
-
- mrc->flags |= MRC_F_PROCESSED;
- }
-}
-
-/* attempt to do a handover */
-static int attempt_handover(struct gsm_meas_rep *mr)
-{
- struct gsm_network *net = mr->lchan->ts->trx->bts->network;
- struct neigh_meas_proc *best_cell = NULL;
- unsigned int best_better_db = 0;
- int i, rc;
-
- /* find the best cell in this report that is at least RXLEV_HYST
- * better than the current serving cell */
-
- for (i = 0; i < ARRAY_SIZE(mr->lchan->neigh_meas); i++) {
- struct neigh_meas_proc *nmp = &mr->lchan->neigh_meas[i];
- int avg, better;
-
- /* skip empty slots */
- if (nmp->arfcn == 0)
- continue;
-
- /* caculate average rxlev for this cell over the window */
- avg = neigh_meas_avg(nmp, net->handover.win_rxlev_avg_neigh);
-
- /* check if hysteresis is fulfilled */
- if (avg < mr->dl.full.rx_lev + net->handover.pwr_hysteresis)
- continue;
-
- better = avg - mr->dl.full.rx_lev;
- if (better > best_better_db) {
- best_cell = nmp;
- best_better_db = better;
- }
- }
-
- if (!best_cell)
- return 0;
-
- LOGP(DHO, LOGL_INFO, "%s: Cell on ARFCN %u is better: ",
- gsm_ts_name(mr->lchan->ts), best_cell->arfcn);
- if (!net->handover.active) {
- LOGPC(DHO, LOGL_INFO, "Skipping, Handover disabled\n");
- return 0;
- }
-
- rc = handover_to_arfcn_bsic(mr->lchan, best_cell->arfcn, best_cell->bsic);
- switch (rc) {
- case 0:
- LOGPC(DHO, LOGL_INFO, "Starting handover\n");
- break;
- case -ENOSPC:
- LOGPC(DHO, LOGL_INFO, "No channel available\n");
- break;
- case -EBUSY:
- LOGPC(DHO, LOGL_INFO, "Handover already active\n");
- break;
- default:
- LOGPC(DHO, LOGL_ERROR, "Unknown error\n");
- }
- return rc;
-}
-
-/* process an already parsed measurement report and decide if we want to
- * attempt a handover */
-static int process_meas_rep(struct gsm_meas_rep *mr)
-{
- struct gsm_network *net = mr->lchan->ts->trx->bts->network;
- enum meas_rep_field dlev, dqual;
- int av_rxlev;
-
- /* we currently only do handover for TCH channels */
- switch (mr->lchan->type) {
- case GSM_LCHAN_TCH_F:
- case GSM_LCHAN_TCH_H:
- break;
- default:
- return 0;
- }
-
- if (mr->flags & MEAS_REP_F_DL_DTX) {
- dlev = MEAS_REP_DL_RXLEV_SUB;
- dqual = MEAS_REP_DL_RXQUAL_SUB;
- } else {
- dlev = MEAS_REP_DL_RXLEV_FULL;
- dqual = MEAS_REP_DL_RXQUAL_FULL;
- }
-
- /* parse actual neighbor cell info */
- if (mr->num_cell > 0 && mr->num_cell < 7)
- process_meas_neigh(mr);
-
- av_rxlev = get_meas_rep_avg(mr->lchan, dlev,
- net->handover.win_rxlev_avg);
-
- /* Interference HO */
- if (rxlev2dbm(av_rxlev) > -85 &&
- meas_rep_n_out_of_m_be(mr->lchan, dqual, 3, 4, 5))
- return attempt_handover(mr);
-
- /* Bad Quality */
- if (meas_rep_n_out_of_m_be(mr->lchan, dqual, 3, 4, 5))
- return attempt_handover(mr);
-
- /* Low Level */
- if (rxlev2dbm(av_rxlev) <= -110)
- return attempt_handover(mr);
-
- /* Distance */
- if (mr->ms_l1.ta > net->handover.max_distance)
- return attempt_handover(mr);
-
- /* Power Budget AKA Better Cell */
- if ((mr->nr % net->handover.pwr_interval) == 0)
- return attempt_handover(mr);
-
- return 0;
-
-}
-
-static int ho_dec_sig_cb(unsigned int subsys, unsigned int signal,
- void *handler_data, void *signal_data)
-{
- struct lchan_signal_data *lchan_data;
-
- if (subsys != SS_LCHAN)
- return 0;
-
- lchan_data = signal_data;
- switch (signal) {
- case S_LCHAN_MEAS_REP:
- process_meas_rep(lchan_data->mr);
- break;
- }
-
- return 0;
-}
-
-void on_dso_load_ho_dec(void)
-{
- osmo_signal_register_handler(SS_LCHAN, ho_dec_sig_cb, NULL);
-}