Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 1 | /* Handover Decision Algorithm 2 for intra-BSC (inter-BTS) handover, public API for OsmoBSC. */ |
| 2 | |
| 3 | /* (C) 2009 by Andreas Eversberg <jolly@eversberg.eu> |
| 4 | * (C) 2017-2018 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| 5 | * |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * Author: Andreas Eversberg <jolly@eversberg.eu> |
| 9 | * Neels Hofmeyr <nhofmeyr@sysmocom.de> |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU Affero General Public License as published by |
| 13 | * the Free Software Foundation; either version 3 of the License, or |
| 14 | * (at your option) any later version. |
| 15 | * |
| 16 | * This program is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU Affero General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU Affero General Public License |
| 22 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 23 | */ |
| 24 | |
| 25 | #include <stdbool.h> |
| 26 | #include <errno.h> |
| 27 | |
| 28 | #include <osmocom/bsc/debug.h> |
| 29 | #include <osmocom/bsc/gsm_data.h> |
| 30 | #include <osmocom/bsc/handover.h> |
| 31 | #include <osmocom/bsc/handover_decision.h> |
| 32 | #include <osmocom/bsc/handover_decision_2.h> |
| 33 | #include <osmocom/bsc/handover_cfg.h> |
| 34 | #include <osmocom/bsc/bsc_subscriber.h> |
| 35 | #include <osmocom/bsc/chan_alloc.h> |
| 36 | #include <osmocom/bsc/signal.h> |
| 37 | #include <osmocom/bsc/penalty_timers.h> |
| 38 | |
| 39 | #define LOGPHOBTS(bts, level, fmt, args...) \ |
| 40 | LOGP(DHODEC, level, "(BTS %u) " fmt, bts->nr, ## args) |
| 41 | |
| 42 | #define LOGPHOLCHAN(lchan, level, fmt, args...) \ |
| 43 | LOGP(DHODEC, level, "(lchan %u.%u%u%u %s) (subscr %s) " fmt, \ |
| 44 | lchan->ts->trx->bts->nr, \ |
| 45 | lchan->ts->trx->nr, \ |
| 46 | lchan->ts->nr, \ |
| 47 | lchan->nr, \ |
| 48 | gsm_pchan_name(lchan->ts->pchan), \ |
Neels Hofmeyr | 0072755 | 2018-02-21 14:33:15 +0100 | [diff] [blame] | 49 | bsc_subscr_name(lchan->conn? lchan->conn->bsub : NULL), \ |
Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 50 | ## args) |
| 51 | |
| 52 | #define LOGPHOLCHANTOBTS(lchan, new_bts, level, fmt, args...) \ |
| 53 | LOGP(DHODEC, level, "(lchan %u.%u%u%u %s)->(BTS %u) (subscr %s) " fmt, \ |
| 54 | lchan->ts->trx->bts->nr, \ |
| 55 | lchan->ts->trx->nr, \ |
| 56 | lchan->ts->nr, \ |
| 57 | lchan->nr, \ |
| 58 | gsm_pchan_name(lchan->ts->pchan), \ |
| 59 | new_bts->nr, \ |
Neels Hofmeyr | 0072755 | 2018-02-21 14:33:15 +0100 | [diff] [blame] | 60 | bsc_subscr_name(lchan->conn? lchan->conn->bsub : NULL), \ |
Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 61 | ## args) |
| 62 | |
| 63 | #define REQUIREMENT_A_TCHF 0x01 |
| 64 | #define REQUIREMENT_B_TCHF 0x02 |
| 65 | #define REQUIREMENT_C_TCHF 0x04 |
| 66 | #define REQUIREMENT_A_TCHH 0x10 |
| 67 | #define REQUIREMENT_B_TCHH 0x20 |
| 68 | #define REQUIREMENT_C_TCHH 0x40 |
| 69 | #define REQUIREMENT_TCHF_MASK (REQUIREMENT_A_TCHF | REQUIREMENT_B_TCHF | REQUIREMENT_C_TCHF) |
| 70 | #define REQUIREMENT_TCHH_MASK (REQUIREMENT_A_TCHH | REQUIREMENT_B_TCHH | REQUIREMENT_C_TCHH) |
| 71 | #define REQUIREMENT_A_MASK (REQUIREMENT_A_TCHF | REQUIREMENT_A_TCHH) |
| 72 | #define REQUIREMENT_B_MASK (REQUIREMENT_B_TCHF | REQUIREMENT_B_TCHH) |
| 73 | #define REQUIREMENT_C_MASK (REQUIREMENT_C_TCHF | REQUIREMENT_C_TCHH) |
| 74 | |
| 75 | struct ho_candidate { |
| 76 | struct gsm_lchan *lchan; /* candidate for whom */ |
| 77 | struct gsm_bts *bts; /* target BTS */ |
| 78 | uint8_t requirements; /* what is fulfilled */ |
| 79 | int avg; /* average RX level */ |
| 80 | }; |
| 81 | |
| 82 | enum ho_reason { |
| 83 | HO_REASON_INTERFERENCE, |
| 84 | HO_REASON_BAD_QUALITY, |
| 85 | HO_REASON_LOW_RXLEVEL, |
| 86 | HO_REASON_MAX_DISTANCE, |
| 87 | HO_REASON_BETTER_CELL, |
| 88 | HO_REASON_CONGESTION, |
| 89 | }; |
| 90 | |
| 91 | static const struct value_string ho_reason_names[] = { |
| 92 | { HO_REASON_INTERFERENCE, "interference (bad quality)" }, |
| 93 | { HO_REASON_BAD_QUALITY, "bad quality" }, |
| 94 | { HO_REASON_LOW_RXLEVEL, "low rxlevel" }, |
| 95 | { HO_REASON_MAX_DISTANCE, "maximum allowed distance" }, |
| 96 | { HO_REASON_BETTER_CELL, "better cell" }, |
| 97 | { HO_REASON_CONGESTION, "congestion" }, |
| 98 | {0, NULL} |
| 99 | }; |
| 100 | |
| 101 | static const char *ho_reason_name(int value) |
| 102 | { |
| 103 | return get_value_string(ho_reason_names, value); |
| 104 | } |
| 105 | |
| 106 | |
| 107 | static bool hodec2_initialized = false; |
| 108 | static enum ho_reason global_ho_reason; |
| 109 | |
| 110 | static void congestion_check_cb(void *arg); |
| 111 | |
| 112 | /* This function gets called on ho2 init, whenever the congestion check interval is changed, and also |
| 113 | * when the timer has fired to trigger again after the next congestion check timeout. */ |
| 114 | static void reinit_congestion_timer(struct gsm_network *net) |
| 115 | { |
| 116 | int congestion_check_interval_s; |
| 117 | bool was_active; |
| 118 | |
| 119 | /* Don't setup timers from VTY config parsing before the main program has actually initialized |
| 120 | * the data structures. */ |
| 121 | if (!hodec2_initialized) |
| 122 | return; |
| 123 | |
| 124 | was_active = net->hodec2.congestion_check_timer.active; |
| 125 | if (was_active) |
| 126 | osmo_timer_del(&net->hodec2.congestion_check_timer); |
| 127 | |
| 128 | congestion_check_interval_s = net->hodec2.congestion_check_interval_s; |
| 129 | if (congestion_check_interval_s < 1) { |
| 130 | if (was_active) |
| 131 | LOGP(DHODEC, LOGL_NOTICE, "HO algorithm 2: Disabling congestion check\n"); |
| 132 | return; |
| 133 | } |
| 134 | |
| 135 | LOGP(DHODEC, LOGL_DEBUG, "HO algorithm 2: next periodical congestion check in %u seconds\n", |
| 136 | congestion_check_interval_s); |
| 137 | |
| 138 | osmo_timer_setup(&net->hodec2.congestion_check_timer, |
| 139 | congestion_check_cb, net); |
| 140 | osmo_timer_schedule(&net->hodec2.congestion_check_timer, |
| 141 | congestion_check_interval_s, 0); |
| 142 | } |
| 143 | |
| 144 | void hodec2_on_change_congestion_check_interval(struct gsm_network *net, unsigned int new_interval) |
| 145 | { |
| 146 | net->hodec2.congestion_check_interval_s = new_interval; |
| 147 | reinit_congestion_timer(net); |
| 148 | } |
| 149 | |
| 150 | static void conn_penalty_time_add(struct gsm_subscriber_connection *conn, struct gsm_bts *bts, |
| 151 | int penalty_time) |
| 152 | { |
| 153 | if (!conn->hodec2.penalty_timers) { |
| 154 | conn->hodec2.penalty_timers = penalty_timers_init(conn); |
| 155 | OSMO_ASSERT(conn->hodec2.penalty_timers); |
| 156 | } |
| 157 | penalty_timers_add(conn->hodec2.penalty_timers, bts, penalty_time); |
| 158 | } |
| 159 | |
| 160 | static unsigned int conn_penalty_time_remaining(struct gsm_subscriber_connection *conn, |
| 161 | struct gsm_bts *bts) |
| 162 | { |
| 163 | if (!conn->hodec2.penalty_timers) |
| 164 | return 0; |
| 165 | return penalty_timers_remaining(conn->hodec2.penalty_timers, bts); |
| 166 | } |
| 167 | |
| 168 | /* did we get a RXLEV for a given cell in the given report? Mark matches as MRC_F_PROCESSED. */ |
| 169 | static struct gsm_meas_rep_cell *cell_in_rep(struct gsm_meas_rep *mr, uint16_t arfcn, uint8_t bsic) |
| 170 | { |
| 171 | int i; |
| 172 | |
| 173 | for (i = 0; i < mr->num_cell; i++) { |
| 174 | struct gsm_meas_rep_cell *mrc = &mr->cell[i]; |
| 175 | |
| 176 | if (mrc->arfcn != arfcn) |
| 177 | continue; |
| 178 | if (mrc->bsic != bsic) |
| 179 | continue; |
| 180 | |
| 181 | return mrc; |
| 182 | } |
| 183 | return NULL; |
| 184 | } |
| 185 | |
| 186 | /* obtain averaged rxlev for given neighbor */ |
| 187 | static int neigh_meas_avg(struct neigh_meas_proc *nmp, int window) |
| 188 | { |
| 189 | unsigned int i, idx; |
| 190 | int avg = 0; |
| 191 | |
| 192 | /* reduce window to the actual number of existing measurements */ |
| 193 | if (window > nmp->rxlev_cnt) |
| 194 | window = nmp->rxlev_cnt; |
| 195 | /* this should never happen */ |
| 196 | if (window <= 0) |
| 197 | return 0; |
| 198 | |
| 199 | idx = calc_initial_idx(ARRAY_SIZE(nmp->rxlev), |
| 200 | nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev), |
| 201 | window); |
| 202 | |
| 203 | for (i = 0; i < window; i++) { |
| 204 | int j = (idx+i) % ARRAY_SIZE(nmp->rxlev); |
| 205 | |
| 206 | avg += nmp->rxlev[j]; |
| 207 | } |
| 208 | |
| 209 | return avg / window; |
| 210 | } |
| 211 | |
| 212 | /* Find empty slot or the worst neighbor. */ |
| 213 | static struct neigh_meas_proc *find_unused_or_worst_neigh(struct gsm_lchan *lchan) |
| 214 | { |
| 215 | struct neigh_meas_proc *nmp_worst = NULL; |
| 216 | int worst; |
| 217 | int j; |
| 218 | |
| 219 | /* First try to find an empty/unused slot. */ |
| 220 | for (j = 0; j < ARRAY_SIZE(lchan->neigh_meas); j++) { |
| 221 | struct neigh_meas_proc *nmp = &lchan->neigh_meas[j]; |
| 222 | if (!nmp->arfcn) |
| 223 | return nmp; |
| 224 | } |
| 225 | |
| 226 | /* No empty slot found. Return worst neighbor to be evicted. */ |
| 227 | worst = 0; /* (overwritten on first loop, but avoid compiler warning) */ |
| 228 | for (j = 0; j < ARRAY_SIZE(lchan->neigh_meas); j++) { |
| 229 | struct neigh_meas_proc *nmp = &lchan->neigh_meas[j]; |
| 230 | int avg = neigh_meas_avg(nmp, MAX_WIN_NEIGH_AVG); |
| 231 | if (nmp_worst && avg >= worst) |
| 232 | continue; |
| 233 | worst = avg; |
| 234 | nmp_worst = nmp; |
| 235 | } |
| 236 | |
| 237 | return nmp_worst; |
| 238 | } |
| 239 | |
| 240 | /* process neighbor cell measurement reports */ |
| 241 | static void process_meas_neigh(struct gsm_meas_rep *mr) |
| 242 | { |
| 243 | int i, j, idx; |
| 244 | |
| 245 | /* For each reported cell, try to update measurements we already have from previous reports. */ |
| 246 | for (j = 0; j < ARRAY_SIZE(mr->lchan->neigh_meas); j++) { |
| 247 | struct neigh_meas_proc *nmp = &mr->lchan->neigh_meas[j]; |
| 248 | unsigned int idx; |
| 249 | struct gsm_meas_rep_cell *mrc; |
| 250 | |
| 251 | /* skip unused entries */ |
| 252 | if (!nmp->arfcn) |
| 253 | continue; |
| 254 | |
| 255 | mrc = cell_in_rep(mr, nmp->arfcn, nmp->bsic); |
| 256 | idx = nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev); |
| 257 | if (mrc) { |
| 258 | nmp->rxlev[idx] = mrc->rxlev; |
| 259 | nmp->last_seen_nr = mr->nr; |
| 260 | LOGPHOLCHAN(mr->lchan, LOGL_DEBUG, "neigh %u rxlev=%d last_seen_nr=%u\n", |
| 261 | nmp->arfcn, mrc->rxlev, nmp->last_seen_nr); |
| 262 | mrc->flags |= MRC_F_PROCESSED; |
| 263 | } else { |
| 264 | nmp->rxlev[idx] = 0; |
| 265 | LOGPHOLCHAN(mr->lchan, LOGL_DEBUG, "neigh %u not in report (last_seen_nr=%u)\n", |
| 266 | nmp->arfcn, nmp->last_seen_nr); |
| 267 | } |
| 268 | nmp->rxlev_cnt++; |
| 269 | } |
| 270 | |
| 271 | /* Add cells that we don't know about yet, if necessary overwriting previous records that reflect |
| 272 | * cells with worse receive levels */ |
| 273 | for (i = 0; i < mr->num_cell; i++) { |
| 274 | struct gsm_meas_rep_cell *mrc = &mr->cell[i]; |
| 275 | struct neigh_meas_proc *nmp; |
| 276 | |
| 277 | if (mrc->flags & MRC_F_PROCESSED) |
| 278 | continue; |
| 279 | |
| 280 | nmp = find_unused_or_worst_neigh(mr->lchan); |
| 281 | |
| 282 | nmp->arfcn = mrc->arfcn; |
| 283 | nmp->bsic = mrc->bsic; |
| 284 | |
| 285 | nmp->rxlev_cnt = 0; |
| 286 | idx = nmp->rxlev_cnt % ARRAY_SIZE(nmp->rxlev); |
| 287 | nmp->rxlev[idx] = mrc->rxlev; |
| 288 | nmp->rxlev_cnt++; |
| 289 | nmp->last_seen_nr = mr->nr; |
| 290 | LOGPHOLCHAN(mr->lchan, LOGL_DEBUG, "neigh %u new in report rxlev=%d last_seen_nr=%u\n", |
| 291 | nmp->arfcn, mrc->rxlev, nmp->last_seen_nr); |
| 292 | |
| 293 | mrc->flags |= MRC_F_PROCESSED; |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | static bool codec_type_is_supported(struct gsm_subscriber_connection *conn, |
| 298 | enum gsm0808_speech_codec_type type) |
| 299 | { |
| 300 | int i; |
| 301 | struct gsm0808_speech_codec_list *clist = &conn->codec_list; |
| 302 | |
| 303 | if (!conn->codec_list_present) { |
| 304 | /* We don't have a list of supported codecs. This should never happen. */ |
| 305 | LOGPHOLCHAN(conn->lchan, LOGL_ERROR, |
| 306 | "No Speech Codec List present, accepting all codecs\n"); |
| 307 | return true; |
| 308 | } |
| 309 | |
| 310 | for (i = 0; i < clist->len; i++) { |
| 311 | if (clist->codec[i].type == type) { |
| 312 | LOGPHOLCHAN(conn->lchan, LOGL_DEBUG, "%s supported\n", |
| 313 | gsm0808_speech_codec_type_name(type)); |
| 314 | return true; |
| 315 | } |
| 316 | } |
| 317 | LOGPHOLCHAN(conn->lchan, LOGL_DEBUG, "Codec not supported by MS or not allowed by MSC: %s\n", |
| 318 | gsm0808_speech_codec_type_name(type)); |
| 319 | return false; |
| 320 | } |
| 321 | |
| 322 | /* |
| 323 | * Check what requirements the given cell fulfills. |
| 324 | * A bit mask of fulfilled requirements is returned. |
| 325 | * |
| 326 | * Target cell requirement A -- ability to service the call |
| 327 | * |
| 328 | * In order to successfully handover/assign to a better cell, the target cell |
| 329 | * must be able to continue the current call. Therefore the cell must fulfill |
| 330 | * the following criteria: |
| 331 | * |
| 332 | * * The handover must be enabled for the target cell, if it differs from the |
| 333 | * originating cell. |
| 334 | * * The assignment must be enabled for the cell, if it equals the current |
| 335 | * cell. |
| 336 | * * The handover penalty timer must not run for the cell. |
| 337 | * * If FR, EFR or HR codec is used, the cell must support this codec. |
| 338 | * * If FR or EFR codec is used, the cell must have a TCH/F slot type |
| 339 | * available. |
| 340 | * * If HR codec is used, the cell must have a TCH/H slot type available. |
| 341 | * * If AMR codec is used, the cell must have a TCH/F slot available, if AFS |
| 342 | * is supported by mobile and BTS. |
| 343 | * * If AMR codec is used, the cell must have a TCH/H slot available, if AHS |
| 344 | * is supported by mobile and BTS. |
| 345 | * * osmo-nitb with built-in MNCC application: |
| 346 | * o If AMR codec is used, the cell must support AMR codec with equal codec |
| 347 | * rate or rates. (not meaning TCH types) |
| 348 | * * If defined, the number of maximum unsynchronized handovers to this cell |
| 349 | * may not be exceeded. (This limits processing load for random access |
| 350 | * bursts.) |
| 351 | * |
| 352 | * |
| 353 | * Target cell requirement B -- avoid congestion |
| 354 | * |
| 355 | * In order to prevent congestion of a target cell, the cell must fulfill the |
| 356 | * requirement A, but also: |
| 357 | * |
| 358 | * * The minimum free channels, that are defined for that cell must be |
| 359 | * maintained after handover/assignment. |
| 360 | * * The minimum free channels are defined for TCH/F and TCH/H slot types |
| 361 | * individually. |
| 362 | * |
| 363 | * |
| 364 | * Target cell requirement C -- balance congestion |
| 365 | * |
| 366 | * In order to balance congested cells, the target cell must fulfill the |
| 367 | * requirement A, but also: |
| 368 | * |
| 369 | * * The target cell (which is congested also) must have more or equal free |
| 370 | * slots after handover/assignment. |
| 371 | * * The number of free slots are checked for TCH/F and TCH/H slot types |
| 372 | * individually. |
| 373 | */ |
| 374 | static uint8_t check_requirements(struct gsm_lchan *lchan, struct gsm_bts *bts, int tchf_count, int tchh_count) |
| 375 | { |
| 376 | int count; |
| 377 | uint8_t requirement = 0; |
| 378 | unsigned int penalty_time; |
| 379 | struct gsm_bts *current_bts = lchan->ts->trx->bts; |
| 380 | |
| 381 | /* Requirement A */ |
| 382 | |
| 383 | /* the handover/assignment must not be disabled */ |
| 384 | if (current_bts == bts) { |
| 385 | if (!ho_get_hodec2_as_active(bts->ho)) { |
| 386 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "Assignment disabled\n"); |
| 387 | return 0; |
| 388 | } |
| 389 | } else { |
| 390 | if (!ho_get_ho_active(bts->ho)) { |
| 391 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 392 | "not a candidate, handover is disabled in target BTS\n"); |
| 393 | return 0; |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | /* the handover penalty timer must not run for this bts */ |
| 398 | penalty_time = conn_penalty_time_remaining(lchan->conn, bts); |
| 399 | if (penalty_time) { |
| 400 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "not a candidate, target BTS still in penalty time" |
| 401 | " (%u seconds left)\n", penalty_time); |
| 402 | return 0; |
| 403 | } |
| 404 | |
| 405 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "tch_mode='%s' type='%s'\n", |
| 406 | get_value_string(gsm48_chan_mode_names, lchan->tch_mode), |
| 407 | gsm_lchant_name(lchan->type)); |
| 408 | |
| 409 | /* compatibility check for codecs. |
| 410 | * if so, the candidates for full rate and half rate are selected */ |
| 411 | switch (lchan->tch_mode) { |
| 412 | case GSM48_CMODE_SPEECH_V1: |
| 413 | switch (lchan->type) { |
| 414 | case GSM_LCHAN_TCH_F: /* mandatory */ |
| 415 | requirement |= REQUIREMENT_A_TCHF; |
| 416 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "tch_mode='%s' type='%s' supported\n", |
| 417 | get_value_string(gsm48_chan_mode_names, lchan->tch_mode), |
| 418 | gsm_lchant_name(lchan->type)); |
| 419 | break; |
| 420 | case GSM_LCHAN_TCH_H: |
| 421 | if (!bts->codec.hr) { |
| 422 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 423 | "tch_mode='%s' type='%s' not supported\n", |
| 424 | get_value_string(gsm48_chan_mode_names, |
| 425 | lchan->tch_mode), |
| 426 | gsm_lchant_name(lchan->type)); |
| 427 | break; |
| 428 | } |
| 429 | if (codec_type_is_supported(lchan->conn, GSM0808_SCT_HR1)) |
| 430 | requirement |= REQUIREMENT_A_TCHH; |
| 431 | break; |
| 432 | default: |
| 433 | LOGPHOLCHAN(lchan, LOGL_ERROR, "Unexpected channel type: neither TCH/F nor TCH/H for %s\n", |
| 434 | get_value_string(gsm48_chan_mode_names, lchan->tch_mode)); |
| 435 | return 0; |
| 436 | } |
| 437 | break; |
| 438 | case GSM48_CMODE_SPEECH_EFR: |
| 439 | if (!bts->codec.efr) { |
| 440 | LOGPHOBTS(bts, LOGL_DEBUG, "EFR not supported\n"); |
| 441 | break; |
| 442 | } |
| 443 | if (codec_type_is_supported(lchan->conn, GSM0808_SCT_FR2)) |
| 444 | requirement |= REQUIREMENT_A_TCHF; |
| 445 | break; |
| 446 | case GSM48_CMODE_SPEECH_AMR: |
| 447 | if (!bts->codec.amr) { |
| 448 | LOGPHOBTS(bts, LOGL_DEBUG, "AMR not supported\n"); |
| 449 | break; |
| 450 | } |
| 451 | if (codec_type_is_supported(lchan->conn, GSM0808_SCT_FR3)) |
| 452 | requirement |= REQUIREMENT_A_TCHF; |
| 453 | if (codec_type_is_supported(lchan->conn, GSM0808_SCT_HR3)) |
| 454 | requirement |= REQUIREMENT_A_TCHH; |
| 455 | break; |
| 456 | default: |
| 457 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "Not even considering: src is not a SPEECH mode lchan\n"); |
| 458 | return 0; |
| 459 | } |
| 460 | |
| 461 | /* no candidate, because new cell is incompatible */ |
| 462 | if (!requirement) { |
| 463 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "not a candidate, because codec of MS and BTS are incompatible\n"); |
| 464 | return 0; |
| 465 | } |
| 466 | |
| 467 | /* remove slot types that are not available */ |
| 468 | if (!tchf_count && requirement & REQUIREMENT_A_TCHF) { |
| 469 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 470 | "removing TCH/F, since all TCH/F lchans are in use\n"); |
| 471 | requirement &= ~(REQUIREMENT_A_TCHF); |
| 472 | } |
| 473 | if (!tchh_count && requirement & REQUIREMENT_A_TCHH) { |
| 474 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 475 | "removing TCH/H, since all TCH/H lchans are in use\n"); |
| 476 | requirement &= ~(REQUIREMENT_A_TCHH); |
| 477 | } |
| 478 | |
| 479 | if (!requirement) { |
| 480 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "not a candidate, because no suitable slots available\n"); |
| 481 | return 0; |
| 482 | } |
| 483 | |
| 484 | /* omit same channel type on same BTS (will not change anything) */ |
| 485 | if (bts == current_bts) { |
| 486 | switch (lchan->type) { |
| 487 | case GSM_LCHAN_TCH_F: |
| 488 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 489 | "removing TCH/F, already on TCH/F in this cell\n"); |
| 490 | requirement &= ~(REQUIREMENT_A_TCHF); |
| 491 | break; |
| 492 | case GSM_LCHAN_TCH_H: |
| 493 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 494 | "removing TCH/H, already on TCH/H in this cell\n"); |
| 495 | requirement &= ~(REQUIREMENT_A_TCHH); |
| 496 | break; |
| 497 | default: |
| 498 | break; |
| 499 | } |
| 500 | |
| 501 | if (!requirement) { |
| 502 | LOGPHOLCHAN(lchan, LOGL_DEBUG, |
| 503 | "Reassignment within cell not an option, no differing channel types available\n"); |
| 504 | return 0; |
| 505 | } |
| 506 | } |
| 507 | |
| 508 | #ifdef LEGACY |
| 509 | // This was useful in osmo-nitb. We're in osmo-bsc now and have no idea whether the osmo-msc does |
| 510 | // internal or external call control. Maybe a future config switch wants to add this behavior? |
| 511 | /* Built-in call control requires equal codec rates. Remove rates that are not equal. */ |
| 512 | if (lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 513 | && current_bts->network->mncc_recv != mncc_sock_from_cc) { |
| 514 | switch (lchan->type) { |
| 515 | case GSM_LCHAN_TCH_F: |
| 516 | if ((requirement & REQUIREMENT_A_TCHF) |
| 517 | && !!memcmp(¤t_bts->mr_full, &bts->mr_full, |
| 518 | sizeof(struct amr_multirate_conf))) |
| 519 | requirement &= ~(REQUIREMENT_A_TCHF); |
| 520 | if ((requirement & REQUIREMENT_A_TCHH) |
| 521 | && !!memcmp(¤t_bts->mr_full, &bts->mr_half, |
| 522 | sizeof(struct amr_multirate_conf))) |
| 523 | requirement &= ~(REQUIREMENT_A_TCHH); |
| 524 | break; |
| 525 | case GSM_LCHAN_TCH_H: |
| 526 | if ((requirement & REQUIREMENT_A_TCHF) |
| 527 | && !!memcmp(¤t_bts->mr_half, &bts->mr_full, |
| 528 | sizeof(struct amr_multirate_conf))) |
| 529 | requirement &= ~(REQUIREMENT_A_TCHF); |
| 530 | if ((requirement & REQUIREMENT_A_TCHH) |
| 531 | && !!memcmp(¤t_bts->mr_half, &bts->mr_half, |
| 532 | sizeof(struct amr_multirate_conf))) |
| 533 | requirement &= ~(REQUIREMENT_A_TCHH); |
| 534 | break; |
| 535 | default: |
| 536 | break; |
| 537 | } |
| 538 | |
| 539 | if (!requirement) { |
| 540 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 541 | "not a candidate, cannot provide identical codec rate\n"); |
| 542 | return 0; |
| 543 | } |
| 544 | } |
| 545 | #endif |
| 546 | |
| 547 | /* the maximum number of unsynchonized handovers must no be exceeded */ |
| 548 | if (current_bts != bts |
| 549 | && bsc_ho_count(bts, true) >= ho_get_hodec2_ho_max(bts->ho)) { |
| 550 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 551 | "not a candidate, number of allowed handovers (%d) would be exceeded\n", |
| 552 | ho_get_hodec2_ho_max(bts->ho)); |
| 553 | return 0; |
| 554 | } |
| 555 | |
| 556 | /* Requirement B */ |
| 557 | |
| 558 | /* the minimum free timeslots that are defined for this cell must |
| 559 | * be maintained _after_ handover/assignment */ |
| 560 | if (requirement & REQUIREMENT_A_TCHF) { |
| 561 | if (tchf_count - 1 >= ho_get_hodec2_tchf_min_slots(bts->ho)) { |
| 562 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 563 | "TCH/F would not be congested after HO\n"); |
| 564 | requirement |= REQUIREMENT_B_TCHF; |
| 565 | } else { |
| 566 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 567 | "TCH/F would be congested after HO\n"); |
| 568 | } |
| 569 | } |
| 570 | if (requirement & REQUIREMENT_A_TCHH) { |
| 571 | if (tchh_count - 1 >= ho_get_hodec2_tchh_min_slots(bts->ho)) { |
| 572 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 573 | "TCH/H would not be congested after HO\n"); |
| 574 | requirement |= REQUIREMENT_B_TCHH; |
| 575 | } else { |
| 576 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 577 | "TCH/H would be congested after HO\n"); |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | /* Requirement C */ |
| 582 | |
| 583 | /* the nr of free timeslots of the target cell must be >= the |
| 584 | * free slots of the current cell _after_ handover/assignment */ |
| 585 | count = bts_count_free_ts(current_bts, |
| 586 | (lchan->type == GSM_LCHAN_TCH_H) ? |
| 587 | GSM_PCHAN_TCH_H : GSM_PCHAN_TCH_F); |
| 588 | if (requirement & REQUIREMENT_A_TCHF) { |
| 589 | if (tchf_count - 1 >= count + 1) { |
| 590 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 591 | "TCH/F would be less congested in target than source cell after HO\n"); |
| 592 | requirement |= REQUIREMENT_C_TCHF; |
| 593 | } else { |
| 594 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 595 | "TCH/F would not be less congested in target than source cell after HO\n"); |
| 596 | } |
| 597 | } |
| 598 | if (requirement & REQUIREMENT_A_TCHH) { |
| 599 | if (tchh_count - 1 >= count + 1) { |
| 600 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 601 | "TCH/H would be less congested in target than source cell after HO\n"); |
| 602 | requirement |= REQUIREMENT_C_TCHH; |
| 603 | } else { |
| 604 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, |
| 605 | "TCH/H would not be less congested in target than source cell after HO\n"); |
| 606 | } |
| 607 | } |
| 608 | |
| 609 | LOGPHOLCHANTOBTS(lchan, bts, LOGL_DEBUG, "requirements=0x%x\n", requirement); |
| 610 | |
| 611 | /* return mask of fulfilled requirements */ |
| 612 | return requirement; |
| 613 | } |
| 614 | |
| 615 | /* Trigger handover or assignment depending on the target BTS */ |
| 616 | static int trigger_handover_or_assignment(struct gsm_lchan *lchan, struct gsm_bts *new_bts, uint8_t requirements) |
| 617 | { |
| 618 | struct gsm_bts *current_bts = lchan->ts->trx->bts; |
| 619 | int afs_bias = 0; |
| 620 | bool full_rate = false; |
| 621 | |
| 622 | if (current_bts == new_bts) |
| 623 | LOGPHOLCHAN(lchan, LOGL_NOTICE, "Triggering Assignment\n"); |
| 624 | else |
| 625 | LOGPHOLCHANTOBTS(lchan, new_bts, LOGL_NOTICE, "Triggering Handover\n"); |
| 626 | |
| 627 | /* afs_bias becomes > 0, if AFS is used and is improved */ |
| 628 | if (lchan->tch_mode == GSM48_CMODE_SPEECH_AMR) |
| 629 | afs_bias = ho_get_hodec2_afs_bias_rxlev(new_bts->ho); |
| 630 | |
| 631 | /* select TCH rate, prefer TCH/F if AFS is improved */ |
| 632 | switch (lchan->type) { |
| 633 | case GSM_LCHAN_TCH_F: |
| 634 | /* keep on full rate, if TCH/F is a candidate */ |
| 635 | if ((requirements & REQUIREMENT_TCHF_MASK)) { |
| 636 | if (current_bts == new_bts) { |
| 637 | LOGPHOLCHAN(lchan, LOGL_INFO, "Not performing assignment: Already on target type\n"); |
| 638 | return 0; |
| 639 | } |
| 640 | full_rate = true; |
| 641 | break; |
| 642 | } |
| 643 | /* change to half rate */ |
| 644 | if (!(requirements & REQUIREMENT_TCHH_MASK)) { |
| 645 | LOGPHOLCHANTOBTS(lchan, new_bts, LOGL_ERROR, |
| 646 | "neither TCH/F nor TCH/H requested, aborting ho/as\n"); |
| 647 | return -EINVAL; |
| 648 | } |
| 649 | break; |
| 650 | case GSM_LCHAN_TCH_H: |
| 651 | /* change to full rate if AFS is improved and a candidate */ |
| 652 | if (afs_bias > 0 && (requirements & REQUIREMENT_TCHF_MASK)) { |
| 653 | full_rate = true; |
| 654 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "[Improve AHS->AFS]\n"); |
| 655 | break; |
| 656 | } |
| 657 | /* change to full rate if the only candidate */ |
| 658 | if ((requirements & REQUIREMENT_TCHF_MASK) |
| 659 | && !(requirements & REQUIREMENT_TCHH_MASK)) { |
| 660 | full_rate = true; |
| 661 | break; |
| 662 | } |
| 663 | /* keep on half rate */ |
| 664 | if (!(requirements & REQUIREMENT_TCHH_MASK)) { |
| 665 | LOGPHOLCHANTOBTS(lchan, new_bts, LOGL_ERROR, |
| 666 | "neither TCH/F nor TCH/H requested, aborting ho/as\n"); |
| 667 | return -EINVAL; |
| 668 | } |
| 669 | if (current_bts == new_bts) { |
| 670 | LOGPHOLCHAN(lchan, LOGL_INFO, "Not performing assignment: Already on target type\n"); |
| 671 | return 0; |
| 672 | } |
| 673 | break; |
| 674 | default: |
| 675 | LOGPHOLCHANTOBTS(lchan, new_bts, LOGL_ERROR, "lchan is neither TCH/F nor TCH/H, aborting ho/as\n"); |
| 676 | return -EINVAL; |
| 677 | } |
| 678 | |
| 679 | /* trigger handover or assignment */ |
| 680 | if (current_bts == new_bts) |
| 681 | LOGPHOLCHAN(lchan, LOGL_NOTICE, "Triggering assignment to %s, due to %s\n", |
| 682 | full_rate ? "TCH/F" : "TCH/H", |
| 683 | ho_reason_name(global_ho_reason)); |
| 684 | else |
| 685 | LOGPHOLCHANTOBTS(lchan, new_bts, LOGL_NOTICE, |
| 686 | "Triggering handover to %s, due to %s\n", |
| 687 | full_rate ? "TCH/F" : "TCH/H", |
| 688 | ho_reason_name(global_ho_reason)); |
| 689 | |
| 690 | return bsc_handover_start(HODEC2, lchan, current_bts == new_bts? NULL : new_bts, |
| 691 | full_rate? GSM_LCHAN_TCH_F : GSM_LCHAN_TCH_H); |
| 692 | } |
| 693 | |
| 694 | /* debug collected candidates */ |
| 695 | static inline void debug_candidate(struct ho_candidate *candidate, |
| 696 | int neighbor, int8_t rxlev, int tchf_count, int tchh_count) |
| 697 | { |
| 698 | if (neighbor) |
| 699 | LOGP(DHODEC, LOGL_DEBUG, " - neighbor BTS %d, RX level " |
| 700 | "%d -> %d\n", candidate->bts->nr, rxlev2dbm(rxlev), |
| 701 | rxlev2dbm(candidate->avg)); |
| 702 | else |
| 703 | LOGP(DHODEC, LOGL_DEBUG, " - current BTS %d, RX level %d\n", |
| 704 | candidate->bts->nr, rxlev2dbm(candidate->avg)); |
| 705 | |
| 706 | LOGP(DHODEC, LOGL_DEBUG, " o free TCH/F slots %d, minimum required " |
| 707 | "%d\n", tchf_count, ho_get_hodec2_tchf_min_slots(candidate->bts->ho)); |
| 708 | LOGP(DHODEC, LOGL_DEBUG, " o free TCH/H slots %d, minimum required " |
| 709 | "%d\n", tchh_count, ho_get_hodec2_tchh_min_slots(candidate->bts->ho)); |
| 710 | |
| 711 | if ((candidate->requirements & REQUIREMENT_TCHF_MASK)) |
| 712 | LOGP(DHODEC, LOGL_DEBUG, " o requirement "); |
| 713 | else |
| 714 | LOGP(DHODEC, LOGL_DEBUG, " o no requirement "); |
| 715 | if ((candidate->requirements & REQUIREMENT_A_TCHF)) |
| 716 | LOGPC(DHODEC, LOGL_DEBUG, "A "); |
| 717 | if ((candidate->requirements & REQUIREMENT_B_TCHF)) |
| 718 | LOGPC(DHODEC, LOGL_DEBUG, "B "); |
| 719 | if ((candidate->requirements & REQUIREMENT_C_TCHF)) |
| 720 | LOGPC(DHODEC, LOGL_DEBUG, "C "); |
| 721 | LOGPC(DHODEC, LOGL_DEBUG, "fulfilled for TCHF"); |
| 722 | if (!(candidate->requirements & REQUIREMENT_TCHF_MASK)) /* nothing */ |
| 723 | LOGPC(DHODEC, LOGL_DEBUG, " (no %s possible)\n", |
| 724 | (neighbor) ? "handover" : "assignment"); |
| 725 | else if ((candidate->requirements & REQUIREMENT_TCHF_MASK) |
| 726 | == REQUIREMENT_A_TCHF) /* only A */ |
| 727 | LOGPC(DHODEC, LOGL_DEBUG, " (more congestion after %s)\n", |
| 728 | (neighbor) ? "handover" : "assignment"); |
| 729 | else if ((candidate->requirements & REQUIREMENT_B_TCHF)) /* B incl. */ |
| 730 | LOGPC(DHODEC, LOGL_DEBUG, " (not congested after %s)\n", |
| 731 | (neighbor) ? "handover" : "assignment"); |
| 732 | else /* so it must include C */ |
| 733 | LOGPC(DHODEC, LOGL_DEBUG, " (less or equally congested after " |
| 734 | "%s)\n", (neighbor) ? "handover" : "assignment"); |
| 735 | |
| 736 | if ((candidate->requirements & REQUIREMENT_TCHH_MASK)) |
| 737 | LOGP(DHODEC, LOGL_DEBUG, " o requirement "); |
| 738 | else |
| 739 | LOGP(DHODEC, LOGL_DEBUG, " o no requirement "); |
| 740 | if ((candidate->requirements & REQUIREMENT_A_TCHH)) |
| 741 | LOGPC(DHODEC, LOGL_DEBUG, "A "); |
| 742 | if ((candidate->requirements & REQUIREMENT_B_TCHH)) |
| 743 | LOGPC(DHODEC, LOGL_DEBUG, "B "); |
| 744 | if ((candidate->requirements & REQUIREMENT_C_TCHH)) |
| 745 | LOGPC(DHODEC, LOGL_DEBUG, "C "); |
| 746 | LOGPC(DHODEC, LOGL_DEBUG, "fulfilled for TCHH"); |
| 747 | if (!(candidate->requirements & REQUIREMENT_TCHH_MASK)) /* nothing */ |
| 748 | LOGPC(DHODEC, LOGL_DEBUG, " (no %s possible)\n", |
| 749 | (neighbor) ? "handover" : "assignment"); |
| 750 | else if ((candidate->requirements & REQUIREMENT_TCHH_MASK) |
| 751 | == REQUIREMENT_A_TCHH) /* only A */ |
| 752 | LOGPC(DHODEC, LOGL_DEBUG, " (more congestion after %s)\n", |
| 753 | (neighbor) ? "handover" : "assignment"); |
| 754 | else if ((candidate->requirements & REQUIREMENT_B_TCHH)) /* B incl. */ |
| 755 | LOGPC(DHODEC, LOGL_DEBUG, " (not congested after %s)\n", |
| 756 | (neighbor) ? "handover" : "assignment"); |
| 757 | else /* so it must include C */ |
| 758 | LOGPC(DHODEC, LOGL_DEBUG, " (less or equally congested after " |
| 759 | "%s)\n", (neighbor) ? "handover" : "assignment"); |
| 760 | } |
| 761 | |
| 762 | /* add candidate for re-assignment within the current cell */ |
| 763 | static void collect_assignment_candidate(struct gsm_lchan *lchan, struct ho_candidate *clist, |
| 764 | unsigned int *candidates, int av_rxlev) |
| 765 | { |
| 766 | struct gsm_bts *bts = lchan->ts->trx->bts; |
| 767 | int tchf_count, tchh_count; |
| 768 | struct ho_candidate *c; |
| 769 | |
| 770 | tchf_count = bts_count_free_ts(bts, GSM_PCHAN_TCH_F); |
| 771 | tchh_count = bts_count_free_ts(bts, GSM_PCHAN_TCH_H); |
| 772 | |
| 773 | c = &clist[*candidates]; |
| 774 | c->lchan = lchan; |
| 775 | c->bts = bts; |
| 776 | c->requirements = check_requirements(lchan, bts, tchf_count, tchh_count); |
| 777 | c->avg = av_rxlev; |
| 778 | debug_candidate(c, 0, 0, tchf_count, tchh_count); |
| 779 | (*candidates)++; |
| 780 | } |
| 781 | |
| 782 | /* add candidates for handover to all neighbor cells */ |
| 783 | static void collect_handover_candidate(struct gsm_lchan *lchan, struct neigh_meas_proc *nmp, |
| 784 | struct ho_candidate *clist, unsigned int *candidates, |
| 785 | bool include_weaker_rxlev, int av_rxlev, |
| 786 | int *neighbors_count) |
| 787 | { |
| 788 | struct gsm_bts *bts = lchan->ts->trx->bts; |
| 789 | int tchf_count, tchh_count; |
| 790 | struct gsm_bts *neighbor_bts; |
| 791 | int avg; |
| 792 | struct ho_candidate *c; |
| 793 | int min_rxlev; |
| 794 | |
| 795 | /* skip empty slots */ |
| 796 | if (nmp->arfcn == 0) |
| 797 | return; |
| 798 | |
| 799 | if (neighbors_count) |
| 800 | (*neighbors_count)++; |
| 801 | |
| 802 | /* skip if measurement report is old */ |
| 803 | if (nmp->last_seen_nr != lchan->meas_rep_last_seen_nr) { |
| 804 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "neighbor ARFCN %u measurement report is old" |
| 805 | " (nmp->last_seen_nr=%u lchan->meas_rep_last_seen_nr=%u)\n", |
| 806 | nmp->arfcn, nmp->last_seen_nr, lchan->meas_rep_last_seen_nr); |
| 807 | return; |
| 808 | } |
| 809 | |
| 810 | neighbor_bts = bts_by_arfcn_bsic(bts->network, nmp->arfcn, nmp->bsic); |
| 811 | if (!neighbor_bts) { |
| 812 | LOGPHOBTS(bts, LOGL_DEBUG, "neighbor ARFCN %u does not belong to this network\n", |
| 813 | nmp->arfcn); |
| 814 | return; |
| 815 | } |
| 816 | |
| 817 | /* in case we have measurements of our bts, due to misconfiguration */ |
| 818 | if (neighbor_bts == bts) { |
| 819 | LOGPHOBTS(bts, LOGL_ERROR, "Configuration error: this BTS appears as its own neighbor\n"); |
| 820 | return; |
| 821 | } |
| 822 | |
| 823 | /* caculate average rxlev for this cell over the window */ |
| 824 | avg = neigh_meas_avg(nmp, ho_get_hodec2_rxlev_neigh_avg_win(bts->ho)); |
| 825 | |
| 826 | /* Heed rxlev hysteresis only if the RXLEV/RXQUAL/TA levels of the MS aren't critically bad and |
| 827 | * we're just looking for an improvement. If levels are critical, we desperately need a handover |
| 828 | * and thus skip the hysteresis check. */ |
| 829 | if (!include_weaker_rxlev) { |
| 830 | unsigned int pwr_hyst = ho_get_hodec2_pwr_hysteresis(bts->ho); |
| 831 | if (avg <= (av_rxlev + pwr_hyst)) { |
| 832 | LOGPHOLCHAN(lchan, LOGL_DEBUG, |
| 833 | "BTS %d is not a candidate, because RX level (%d) is lower" |
| 834 | " or equal than current RX level (%d) + hysteresis (%d)\n", |
| 835 | neighbor_bts->nr, rxlev2dbm(avg), rxlev2dbm(av_rxlev), pwr_hyst); |
| 836 | return; |
| 837 | } |
| 838 | } |
| 839 | |
| 840 | /* if the minimum level is not reached */ |
| 841 | min_rxlev = ho_get_hodec2_min_rxlev(neighbor_bts->ho); |
| 842 | if (rxlev2dbm(avg) < min_rxlev) { |
| 843 | LOGPHOLCHAN(lchan, LOGL_DEBUG, |
| 844 | "BTS %d is not a candidate, because RX level (%d) is lower" |
| 845 | " than its minimum required RX level (%d)\n", |
| 846 | neighbor_bts->nr, rxlev2dbm(avg), min_rxlev); |
| 847 | return; |
| 848 | } |
| 849 | |
| 850 | tchf_count = bts_count_free_ts(neighbor_bts, GSM_PCHAN_TCH_F); |
| 851 | tchh_count = bts_count_free_ts(neighbor_bts, GSM_PCHAN_TCH_H); |
| 852 | c = &clist[*candidates]; |
| 853 | c->lchan = lchan; |
| 854 | c->bts = neighbor_bts; |
| 855 | c->requirements = check_requirements(lchan, neighbor_bts, tchf_count, |
| 856 | tchh_count); |
| 857 | c->avg = avg; |
| 858 | debug_candidate(c, 1, av_rxlev, tchf_count, tchh_count); |
| 859 | (*candidates)++; |
| 860 | } |
| 861 | |
| 862 | static void collect_candidates_for_lchan(struct gsm_lchan *lchan, |
| 863 | struct ho_candidate *clist, unsigned int *candidates, |
| 864 | int *_av_rxlev, bool include_weaker_rxlev) |
| 865 | { |
| 866 | struct gsm_bts *bts = lchan->ts->trx->bts; |
| 867 | int av_rxlev; |
| 868 | unsigned int candidates_was; |
| 869 | bool assignment; |
| 870 | bool handover; |
| 871 | int neighbors_count = 0; |
| 872 | unsigned int rxlev_avg_win = ho_get_hodec2_rxlev_avg_win(bts->ho); |
| 873 | |
| 874 | OSMO_ASSERT(candidates); |
| 875 | candidates_was = *candidates; |
| 876 | |
| 877 | /* caculate average rxlev for this cell over the window */ |
| 878 | av_rxlev = get_meas_rep_avg(lchan, |
| 879 | ho_get_hodec2_full_tdma(bts->ho) ? |
| 880 | MEAS_REP_DL_RXLEV_FULL : MEAS_REP_DL_RXLEV_SUB, |
| 881 | rxlev_avg_win); |
| 882 | if (_av_rxlev) |
| 883 | *_av_rxlev = av_rxlev; |
| 884 | |
| 885 | /* in case there is no measurment report (yet) */ |
| 886 | if (av_rxlev < 0) { |
| 887 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "Not collecting candidates, not enough measurements" |
| 888 | " (got %d, want %u)\n", |
| 889 | lchan->meas_rep_count, rxlev_avg_win); |
| 890 | return; |
| 891 | } |
| 892 | |
| 893 | assignment = ho_get_hodec2_as_active(bts->ho); |
| 894 | handover = ho_get_ho_active(bts->ho); |
| 895 | |
| 896 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "Collecting candidates for%s%s%s\n", |
| 897 | assignment ? " Assignment" : "", |
| 898 | assignment && handover ? " and" : "", |
| 899 | handover ? " Handover" : ""); |
| 900 | |
| 901 | if (assignment) |
| 902 | collect_assignment_candidate(lchan, clist, candidates, av_rxlev); |
| 903 | |
| 904 | if (handover) { |
| 905 | int i; |
| 906 | for (i = 0; i < ARRAY_SIZE(lchan->neigh_meas); i++) { |
| 907 | collect_handover_candidate(lchan, &lchan->neigh_meas[i], |
| 908 | clist, candidates, |
| 909 | include_weaker_rxlev, av_rxlev, &neighbors_count); |
| 910 | } |
| 911 | } |
| 912 | |
| 913 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "adding %u candidates from %u neighbors, total %u\n", |
| 914 | *candidates - candidates_was, neighbors_count, *candidates); |
| 915 | } |
| 916 | |
| 917 | /* |
| 918 | * Search for a alternative / better cell. |
| 919 | * |
| 920 | * Do not trigger handover/assignment on slots which have already ongoing |
| 921 | * handover/assignment processes. If no AFS improvement offset is given, try to |
| 922 | * maintain the same TCH rate, if available. |
| 923 | * Do not perform this process, if handover and assignment are disabled for |
| 924 | * the current cell. |
| 925 | * Do not perform handover, if the minimum acceptable RX level |
| 926 | * is not reched for this cell. |
| 927 | * |
| 928 | * If one or more 'better cells' are available, check the current and neighbor |
| 929 | * cell measurements in descending order of their RX levels (down-link): |
| 930 | * |
| 931 | * * Select the best candidate that fulfills requirement B (no congestion |
| 932 | * after handover/assignment) and trigger handover or assignment. |
| 933 | * * If no candidate fulfills requirement B, select the best candidate that |
| 934 | * fulfills requirement C (less or equally congested cells after handover) |
| 935 | * and trigger handover or assignment. |
| 936 | * * If no candidate fulfills requirement C, do not perform handover nor |
| 937 | * assignment. |
| 938 | * |
| 939 | * If the RX level (down-link) or RX quality (down-link) of the current cell is |
| 940 | * below minimum acceptable level, or if the maximum allowed timing advance is |
| 941 | * reached or exceeded, check the RX levels (down-link) of the current and |
| 942 | * neighbor cells in descending order of their levels: (bad BTS case) |
| 943 | * |
| 944 | * * Select the best candidate that fulfills requirement B (no congestion after |
| 945 | * handover/assignment) and trigger handover or assignment. |
| 946 | * * If no candidate fulfills requirement B, select the best candidate that |
| 947 | * fulfills requirement C (less or equally congested cells after handover) |
| 948 | * and trigger handover or assignment. |
| 949 | * * If no candidate fulfills requirement C, select the best candidate that |
| 950 | * fulfills requirement A (ignore congestion after handover or assignment) |
| 951 | * and trigger handover or assignment. |
| 952 | * * If no candidate fulfills requirement A, do not perform handover nor |
| 953 | * assignment. |
| 954 | * |
| 955 | * RX levels (down-link) of current and neighbor cells: |
| 956 | * |
| 957 | * * The RX levels of the current cell and neighbor cells are improved by a |
| 958 | * given offset, if AFS (AMR on TCH/F) is used or is a candidate for |
| 959 | * handover/assignment. |
| 960 | * * If AMR is used, the requirement for handover is checked for TCH/F and |
| 961 | * TCH/H. Both results (if any) are used as a candidate. |
| 962 | * * If AMR is used, the requirement for assignment to a different TCH slot |
| 963 | * rate is checked. The result (if available) is used as a candidate. |
| 964 | * |
| 965 | * If minimum RXLEV, minimum RXQUAL or maximum TA are exceeded, the caller should pass |
| 966 | * include_weaker_rxlev=true so that handover is performed despite congestion. |
| 967 | */ |
| 968 | static int find_alternative_lchan(struct gsm_lchan *lchan, bool include_weaker_rxlev) |
| 969 | { |
| 970 | struct gsm_bts *bts = lchan->ts->trx->bts; |
| 971 | int ahs = (lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 972 | && lchan->type == GSM_LCHAN_TCH_H); |
| 973 | int av_rxlev; |
| 974 | struct ho_candidate clist[1 + ARRAY_SIZE(lchan->neigh_meas)]; |
| 975 | unsigned int candidates = 0; |
| 976 | int i; |
| 977 | struct ho_candidate *best_cand = NULL; |
| 978 | unsigned int best_better_db; |
| 979 | bool best_applied_afs_bias = false; |
| 980 | int better; |
| 981 | |
| 982 | /* check for disabled handover/assignment at the current cell */ |
| 983 | if (!ho_get_hodec2_as_active(bts->ho) |
| 984 | && !ho_get_ho_active(bts->ho)) { |
| 985 | LOGP(DHODEC, LOGL_INFO, "Skipping, Handover and Assignment both disabled in this cell\n"); |
| 986 | return 0; |
| 987 | } |
| 988 | |
| 989 | collect_candidates_for_lchan(lchan, clist, &candidates, &av_rxlev, include_weaker_rxlev); |
| 990 | |
| 991 | /* If assignment is disabled and no neighbor cell report exists, or no neighbor cell qualifies, |
| 992 | * we may not even have any candidates. */ |
| 993 | if (!candidates) |
| 994 | goto no_candidates; |
| 995 | |
| 996 | /* select best candidate that fulfills requirement B: no congestion after HO */ |
| 997 | best_better_db = 0; |
| 998 | for (i = 0; i < candidates; i++) { |
| 999 | int afs_bias; |
| 1000 | if (!(clist[i].requirements & REQUIREMENT_B_MASK)) |
| 1001 | continue; |
| 1002 | |
| 1003 | better = clist[i].avg - av_rxlev; |
| 1004 | /* Apply AFS bias? */ |
| 1005 | afs_bias = 0; |
| 1006 | if (ahs && (clist[i].requirements & REQUIREMENT_B_TCHF)) |
| 1007 | afs_bias = ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1008 | better += afs_bias; |
| 1009 | if (better > best_better_db) { |
| 1010 | best_cand = &clist[i]; |
| 1011 | best_better_db = better; |
| 1012 | best_applied_afs_bias = afs_bias? true : false; |
| 1013 | } |
| 1014 | } |
| 1015 | |
| 1016 | /* perform handover, if there is a candidate */ |
| 1017 | if (best_cand) { |
| 1018 | LOGPHOLCHANTOBTS(lchan, best_cand->bts, LOGL_INFO, "Best candidate, RX level %d%s\n", |
| 1019 | rxlev2dbm(best_cand->avg), |
| 1020 | best_applied_afs_bias ? " (applied AHS -> AFS rxlev bias)" : ""); |
| 1021 | return trigger_handover_or_assignment(lchan, best_cand->bts, |
| 1022 | best_cand->requirements & REQUIREMENT_B_MASK); |
| 1023 | } |
| 1024 | |
| 1025 | /* select best candidate that fulfills requirement C: less or equal congestion after HO */ |
| 1026 | best_better_db = 0; |
| 1027 | for (i = 0; i < candidates; i++) { |
| 1028 | int afs_bias; |
| 1029 | if (!(clist[i].requirements & REQUIREMENT_C_MASK)) |
| 1030 | continue; |
| 1031 | |
| 1032 | better = clist[i].avg - av_rxlev; |
| 1033 | /* Apply AFS bias? */ |
| 1034 | afs_bias = 0; |
| 1035 | if (ahs && (clist[i].requirements & REQUIREMENT_C_TCHF)) |
| 1036 | afs_bias = ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1037 | better += afs_bias; |
| 1038 | if (better > best_better_db) { |
| 1039 | best_cand = &clist[i]; |
| 1040 | best_better_db = better; |
| 1041 | best_applied_afs_bias = afs_bias? true : false; |
| 1042 | } |
| 1043 | } |
| 1044 | |
| 1045 | /* perform handover, if there is a candidate */ |
| 1046 | if (best_cand) { |
| 1047 | LOGPHOLCHANTOBTS(lchan, best_cand->bts, LOGL_INFO, "Best candidate, RX level %d%s\n", |
| 1048 | rxlev2dbm(best_cand->avg), |
| 1049 | best_applied_afs_bias? " (applied AHS -> AFS rxlev bias)" : ""); |
| 1050 | return trigger_handover_or_assignment(lchan, best_cand->bts, |
| 1051 | best_cand->requirements & REQUIREMENT_C_MASK); |
| 1052 | } |
| 1053 | |
| 1054 | /* we are done in case the MS RXLEV/RXQUAL/TA aren't critical and we're avoiding congestion. */ |
| 1055 | if (!include_weaker_rxlev) |
| 1056 | goto no_candidates; |
| 1057 | |
| 1058 | /* Select best candidate that fulfills requirement A: can service the call. |
| 1059 | * From above we know that there are no options that avoid congestion. Here we're trying to find |
| 1060 | * *any* free lchan that has no critically low RXLEV and is able to handle the MS. */ |
| 1061 | best_better_db = 0; |
| 1062 | for (i = 0; i < candidates; i++) { |
| 1063 | int afs_bias; |
| 1064 | if (!(clist[i].requirements & REQUIREMENT_A_MASK)) |
| 1065 | continue; |
| 1066 | |
| 1067 | better = clist[i].avg - av_rxlev; |
| 1068 | /* Apply AFS bias? */ |
| 1069 | afs_bias = 0; |
| 1070 | if (ahs && (clist[i].requirements & REQUIREMENT_A_TCHF)) |
| 1071 | afs_bias = ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1072 | better += afs_bias; |
| 1073 | if (better > best_better_db) { |
| 1074 | best_cand = &clist[i]; |
| 1075 | best_better_db = better; |
| 1076 | best_applied_afs_bias = afs_bias? true : false; |
| 1077 | } |
| 1078 | } |
| 1079 | |
| 1080 | /* perform handover, if there is a candidate */ |
| 1081 | if (best_cand) { |
| 1082 | LOGPHOLCHANTOBTS(lchan, best_cand->bts, LOGL_INFO, "Best candidate, RX level %d" |
| 1083 | " with greater congestion found%s\n", |
| 1084 | rxlev2dbm(best_cand->avg), |
| 1085 | best_applied_afs_bias ? " (applied AHS -> AFS rxlev bias)" : ""); |
| 1086 | return trigger_handover_or_assignment(lchan, best_cand->bts, |
| 1087 | best_cand->requirements & REQUIREMENT_A_MASK); |
| 1088 | } |
| 1089 | |
| 1090 | /* Damn, all is congested, has too low RXLEV or cannot service the voice call due to codec |
| 1091 | * restrictions or because all lchans are taken. */ |
| 1092 | |
| 1093 | no_candidates: |
| 1094 | if (include_weaker_rxlev) |
| 1095 | LOGPHOLCHAN(lchan, LOGL_INFO, "No alternative lchan found\n"); |
| 1096 | else |
| 1097 | LOGPHOLCHAN(lchan, LOGL_INFO, "No better/less congested neighbor cell found\n"); |
| 1098 | |
| 1099 | return 0; |
| 1100 | } |
| 1101 | |
| 1102 | /* |
| 1103 | * Handover/assignment check, if measurement report is received |
| 1104 | * |
| 1105 | * Do not trigger handover/assignment on slots which have already ongoing |
| 1106 | * handover/assignment processes. |
| 1107 | * |
| 1108 | * In case of handover triggered because maximum allowed timing advance is |
| 1109 | * exceeded, the handover penalty timer is started for the originating cell. |
| 1110 | * |
| 1111 | */ |
| 1112 | static void on_measurement_report(struct gsm_meas_rep *mr) |
| 1113 | { |
| 1114 | struct gsm_lchan *lchan = mr->lchan; |
| 1115 | struct gsm_bts *bts = lchan->ts->trx->bts; |
| 1116 | int av_rxlev = -EINVAL, av_rxqual = -EINVAL; |
Neels Hofmeyr | 0072755 | 2018-02-21 14:33:15 +0100 | [diff] [blame] | 1117 | unsigned int pwr_interval; |
Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 1118 | |
| 1119 | /* we currently only do handover for TCH channels */ |
| 1120 | switch (mr->lchan->type) { |
| 1121 | case GSM_LCHAN_TCH_F: |
| 1122 | case GSM_LCHAN_TCH_H: |
| 1123 | break; |
| 1124 | default: |
| 1125 | return; |
| 1126 | } |
| 1127 | |
| 1128 | if (log_check_level(DHODEC, LOGL_DEBUG)) { |
| 1129 | int i; |
| 1130 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "MEASUREMENT REPORT\n"); |
| 1131 | for (i = 0; i < mr->num_cell; i++) { |
| 1132 | struct gsm_meas_rep_cell *mrc = &mr->cell[i]; |
| 1133 | LOGPHOLCHAN(lchan, LOGL_DEBUG, |
| 1134 | " %d: arfcn=%u bsic=%u neigh_idx=%u rxlev=%u flags=%x\n", |
| 1135 | i, mrc->arfcn, mrc->bsic, mrc->neigh_idx, mrc->rxlev, mrc->flags); |
| 1136 | } |
| 1137 | } |
| 1138 | |
| 1139 | /* parse actual neighbor cell info */ |
| 1140 | if (mr->num_cell > 0 && mr->num_cell < 7) |
| 1141 | process_meas_neigh(mr); |
| 1142 | |
| 1143 | /* check for ongoing handover/assignment */ |
| 1144 | if (!lchan->conn) { |
| 1145 | LOGPHOLCHAN(lchan, LOGL_ERROR, "Skipping, No subscriber connection???\n"); |
| 1146 | return; |
| 1147 | } |
| 1148 | if (lchan->conn->secondary_lchan) { |
| 1149 | LOGPHOLCHAN(lchan, LOGL_INFO, "Skipping, Initial Assignment is still ongoing\n"); |
| 1150 | return; |
| 1151 | } |
| 1152 | if (lchan->conn->ho_lchan) { |
| 1153 | LOGPHOLCHAN(lchan, LOGL_INFO, "Skipping, Handover already triggered\n"); |
| 1154 | return; |
| 1155 | } |
| 1156 | |
| 1157 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "HODEC2: evaluating measurement report\n"); |
| 1158 | |
| 1159 | /* get average levels. if not enought measurements yet, value is < 0 */ |
| 1160 | av_rxlev = get_meas_rep_avg(lchan, |
| 1161 | ho_get_hodec2_full_tdma(bts->ho) ? |
| 1162 | MEAS_REP_DL_RXLEV_FULL : MEAS_REP_DL_RXLEV_SUB, |
| 1163 | ho_get_hodec2_rxlev_avg_win(bts->ho)); |
| 1164 | av_rxqual = get_meas_rep_avg(lchan, |
| 1165 | ho_get_hodec2_full_tdma(bts->ho) ? |
| 1166 | MEAS_REP_DL_RXQUAL_FULL : MEAS_REP_DL_RXQUAL_SUB, |
| 1167 | ho_get_hodec2_rxqual_avg_win(bts->ho)); |
| 1168 | if (av_rxlev < 0 && av_rxqual < 0) { |
| 1169 | LOGPHOLCHAN(lchan, LOGL_INFO, "Skipping, Not enough recent measuements\n"); |
| 1170 | return; |
| 1171 | } |
| 1172 | if (av_rxlev >= 0) { |
| 1173 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "Measurement report: average RX level = %d\n", |
| 1174 | rxlev2dbm(av_rxlev)); |
| 1175 | } |
| 1176 | if (av_rxqual >= 0) { |
| 1177 | LOGPHOLCHAN(lchan, LOGL_DEBUG, "Measurement report: average RX quality = %d\n", |
| 1178 | av_rxqual); |
| 1179 | } |
| 1180 | |
| 1181 | /* improve levels in case of AFS, if defined */ |
| 1182 | if (lchan->type == GSM_LCHAN_TCH_F |
| 1183 | && lchan->tch_mode == GSM48_CMODE_SPEECH_AMR) { |
| 1184 | int rxlev_bias = ho_get_hodec2_afs_bias_rxlev(bts->ho); |
| 1185 | int rxqual_bias = ho_get_hodec2_afs_bias_rxqual(bts->ho); |
| 1186 | if (av_rxlev >= 0 && rxlev_bias) { |
| 1187 | int imp = av_rxlev + rxlev_bias; |
| 1188 | LOGPHOLCHAN(lchan, LOGL_INFO, "Virtually improving RX level from %d to %d," |
| 1189 | " due to AFS bias\n", rxlev2dbm(av_rxlev), rxlev2dbm(imp)); |
| 1190 | av_rxlev = imp; |
| 1191 | } |
| 1192 | if (av_rxqual >= 0 && rxqual_bias) { |
| 1193 | int imp = av_rxqual - rxqual_bias; |
| 1194 | if (imp < 0) |
| 1195 | imp = 0; |
| 1196 | LOGPHOLCHAN(lchan, LOGL_INFO, "Virtually improving RX quality from %d to %d," |
| 1197 | " due to AFS bias\n", rxlev2dbm(av_rxqual), rxlev2dbm(imp)); |
| 1198 | av_rxqual = imp; |
| 1199 | } |
| 1200 | } |
| 1201 | |
| 1202 | /* Bad Quality */ |
| 1203 | if (av_rxqual >= 0 && av_rxqual > ho_get_hodec2_min_rxqual(bts->ho)) { |
| 1204 | if (rxlev2dbm(av_rxlev) > -85) { |
| 1205 | global_ho_reason = HO_REASON_INTERFERENCE; |
| 1206 | LOGPHOLCHAN(lchan, LOGL_INFO, "Trying handover/assignment" |
| 1207 | " due to interference (bad quality)\n"); |
| 1208 | } else { |
| 1209 | global_ho_reason = HO_REASON_BAD_QUALITY; |
| 1210 | LOGPHOLCHAN(lchan, LOGL_INFO, "Trying handover/assignment due to bad quality\n"); |
| 1211 | } |
| 1212 | find_alternative_lchan(lchan, true); |
| 1213 | return; |
| 1214 | } |
| 1215 | |
| 1216 | /* Low Level */ |
| 1217 | if (av_rxlev >= 0 && rxlev2dbm(av_rxlev) < ho_get_hodec2_min_rxlev(bts->ho)) { |
| 1218 | global_ho_reason = HO_REASON_LOW_RXLEVEL; |
| 1219 | LOGPHOLCHAN(lchan, LOGL_INFO, "Attempting handover/assignment due to low rxlev\n"); |
| 1220 | find_alternative_lchan(lchan, true); |
| 1221 | return; |
| 1222 | } |
| 1223 | |
| 1224 | /* Max Distance */ |
| 1225 | if (lchan->meas_rep_count > 0 |
| 1226 | && lchan->rqd_ta > ho_get_hodec2_max_distance(bts->ho)) { |
| 1227 | global_ho_reason = HO_REASON_MAX_DISTANCE; |
| 1228 | LOGPHOLCHAN(lchan, LOGL_INFO, "Attempting handover due to high TA\n"); |
| 1229 | /* start penalty timer to prevent comming back too |
| 1230 | * early. it must be started before selecting a better cell, |
| 1231 | * so there is no assignment selected, due to running |
| 1232 | * penalty timer. */ |
| 1233 | conn_penalty_time_add(lchan->conn, bts, ho_get_hodec2_penalty_max_dist(bts->ho)); |
| 1234 | find_alternative_lchan(lchan, true); |
| 1235 | return; |
| 1236 | } |
| 1237 | |
Neels Hofmeyr | 0072755 | 2018-02-21 14:33:15 +0100 | [diff] [blame] | 1238 | /* pwr_interval's range is 1-99, clarifying that no div-zero shall happen in modulo below: */ |
| 1239 | pwr_interval = ho_get_hodec2_pwr_interval(bts->ho); |
| 1240 | OSMO_ASSERT(pwr_interval); |
| 1241 | |
Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 1242 | /* try handover to a better cell */ |
Neels Hofmeyr | 0072755 | 2018-02-21 14:33:15 +0100 | [diff] [blame] | 1243 | if (av_rxlev >= 0 && (mr->nr % pwr_interval) == 0) { |
Neels Hofmeyr | 909e972 | 2017-12-07 03:54:01 +0100 | [diff] [blame] | 1244 | LOGPHOLCHAN(lchan, LOGL_INFO, "Looking whether a cell has better RXLEV\n"); |
| 1245 | global_ho_reason = HO_REASON_BETTER_CELL; |
| 1246 | find_alternative_lchan(lchan, false); |
| 1247 | } |
| 1248 | } |
| 1249 | |
| 1250 | /* |
| 1251 | * Handover/assignment check after timer timeout: |
| 1252 | * |
| 1253 | * Even if handover process tries to prevent a congestion, a cell might get |
| 1254 | * congested due to new call setups or handovers to prevent loss of radio link. |
| 1255 | * A cell is congested, if not the minimum number of free slots are available. |
| 1256 | * The minimum number can be defined for TCH/F and TCH/H individually. |
| 1257 | * |
| 1258 | * Do not perform congestion check, if no minimum free slots are defined for |
| 1259 | * a cell. |
| 1260 | * Do not trigger handover/assignment on slots which have already ongoing |
| 1261 | * handover/assignment processes. If no AFS improvement offset is given, try to |
| 1262 | * maintain the same TCH rate, if available. |
| 1263 | * Do not perform this process, if handover and assignment are disabled for |
| 1264 | * the current cell. |
| 1265 | * Do not perform handover, if the minimum acceptable RX level |
| 1266 | * is not reched for this cell. |
| 1267 | * Only check candidates that will solve/reduce congestion. |
| 1268 | * |
| 1269 | * If a cell is congested, all slots are checked for all their RX levels |
| 1270 | * (down-link) of the current and neighbor cell measurements in descending |
| 1271 | * order of their RX levels: |
| 1272 | * |
| 1273 | * * Select the best candidate that fulfills requirement B (no congestion after |
| 1274 | * handover/assignment), trigger handover or assignment. Candidates that will |
| 1275 | * cause an assignment from AHS (AMR on TCH/H) to AFS (AMR on TCH/F) are |
| 1276 | * omitted. |
| 1277 | * o This process repeated until the minimum required number of free slots |
| 1278 | * are restored or if all cell measurements are checked. The process ends |
| 1279 | * then, otherwise: |
| 1280 | * * Select the worst candidate that fulfills requirement B, trigger |
| 1281 | * assignment. Note that only assignment candidates for changing from AHS to |
| 1282 | * AFS are left. |
| 1283 | * o This process repeated until the minimum required number of free slots |
| 1284 | * are restored or if all cell measurements are checked. The process ends |
| 1285 | * then, otherwise: |
| 1286 | * * Select the best candidates that fulfill requirement C (less or equally |
| 1287 | * congested cells after handover/assignment), trigger handover or |
| 1288 | * assignment. Candidates that will cause an assignment from AHS (AMR on |
| 1289 | * TCH/H) to AFS (AMR on TCH/F) are omitted. |
| 1290 | * o This process repeated until the minimum required number of free slots |
| 1291 | * are restored or if all cell measurements are checked. The process ends |
| 1292 | * then, otherwise: |
| 1293 | * * Select the worst candidate that fulfills requirement C, trigger |
| 1294 | * assignment. Note that only assignment candidates for changing from AHS to |
| 1295 | * AFS are left. |
| 1296 | * o This process repeated until the minimum required number of free slots |
| 1297 | * are restored or if all cell measurements are checked. |
| 1298 | */ |
| 1299 | static int bts_resolve_congestion(struct gsm_bts *bts, int tchf_congestion, int tchh_congestion) |
| 1300 | { |
| 1301 | struct gsm_lchan *lc; |
| 1302 | struct gsm_bts_trx *trx; |
| 1303 | struct gsm_bts_trx_ts *ts; |
| 1304 | int i, j; |
| 1305 | struct ho_candidate *clist; |
| 1306 | unsigned int candidates; |
| 1307 | struct ho_candidate *best_cand = NULL, *worst_cand = NULL; |
| 1308 | struct gsm_lchan *delete_lchan = NULL; |
| 1309 | unsigned int best_avg_db, worst_avg_db; |
| 1310 | int avg; |
| 1311 | int rc = 0; |
| 1312 | int any_ho = 0; |
| 1313 | int is_improved = 0; |
| 1314 | |
| 1315 | if (tchf_congestion < 0) |
| 1316 | tchf_congestion = 0; |
| 1317 | if (tchh_congestion < 0) |
| 1318 | tchh_congestion = 0; |
| 1319 | |
| 1320 | LOGPHOBTS(bts, LOGL_INFO, "congested: %d TCH/F and %d TCH/H should be moved\n", |
| 1321 | tchf_congestion, tchh_congestion); |
| 1322 | |
| 1323 | /* allocate array of all bts */ |
| 1324 | clist = talloc_zero_array(tall_bsc_ctx, struct ho_candidate, |
| 1325 | bts->num_trx * 8 * 2 * (1 + ARRAY_SIZE(lc->neigh_meas))); |
| 1326 | if (!clist) |
| 1327 | return 0; |
| 1328 | |
| 1329 | candidates = 0; |
| 1330 | |
| 1331 | /* loop through all active lchan and collect candidates */ |
| 1332 | llist_for_each_entry(trx, &bts->trx_list, list) { |
| 1333 | if (!trx_is_usable(trx)) |
| 1334 | continue; |
| 1335 | |
| 1336 | for (i = 0; i < 8; i++) { |
| 1337 | ts = &trx->ts[i]; |
| 1338 | if (!ts_is_usable(ts)) |
| 1339 | continue; |
| 1340 | |
| 1341 | /* (Do not consider dynamic TS that are in PDCH mode) */ |
| 1342 | switch (ts_pchan(ts)) { |
| 1343 | case GSM_PCHAN_TCH_F: |
| 1344 | lc = &ts->lchan[0]; |
| 1345 | /* omit if channel not active */ |
| 1346 | if (lc->type != GSM_LCHAN_TCH_F |
| 1347 | || lc->state != LCHAN_S_ACTIVE) |
| 1348 | break; |
| 1349 | /* omit if there is an ongoing ho/as */ |
| 1350 | if (!lc->conn || lc->conn->secondary_lchan |
| 1351 | || lc->conn->ho_lchan) |
| 1352 | break; |
| 1353 | /* We desperately want to resolve congestion, ignore rxlev when |
| 1354 | * collecting candidates by passing include_weaker_rxlev=true. */ |
| 1355 | collect_candidates_for_lchan(lc, clist, &candidates, NULL, true); |
| 1356 | break; |
| 1357 | case GSM_PCHAN_TCH_H: |
| 1358 | for (j = 0; j < 2; j++) { |
| 1359 | lc = &ts->lchan[j]; |
| 1360 | /* omit if channel not active */ |
| 1361 | if (lc->type != GSM_LCHAN_TCH_H |
| 1362 | || lc->state != LCHAN_S_ACTIVE) |
| 1363 | continue; |
| 1364 | /* omit of there is an ongoing ho/as */ |
| 1365 | if (!lc->conn |
| 1366 | || lc->conn->secondary_lchan |
| 1367 | || lc->conn->ho_lchan) |
| 1368 | continue; |
| 1369 | /* We desperately want to resolve congestion, ignore rxlev when |
| 1370 | * collecting candidates by passing include_weaker_rxlev=true. */ |
| 1371 | collect_candidates_for_lchan(lc, clist, &candidates, NULL, true); |
| 1372 | } |
| 1373 | break; |
| 1374 | default: |
| 1375 | break; |
| 1376 | } |
| 1377 | } |
| 1378 | } |
| 1379 | |
| 1380 | if (!candidates) { |
| 1381 | LOGPHOBTS(bts, LOGL_DEBUG, "No neighbor cells qualify to solve congestion\n"); |
| 1382 | goto exit; |
| 1383 | } |
| 1384 | if (log_check_level(DHODEC, LOGL_DEBUG)) { |
| 1385 | LOGPHOBTS(bts, LOGL_DEBUG, "Considering %u candidates to solve congestion:\n", candidates); |
| 1386 | for (i = 0; i < candidates; i++) { |
| 1387 | LOGPHOLCHANTOBTS(clist[i].lchan, clist[i].bts, LOGL_DEBUG, |
| 1388 | "#%d: req=0x%x avg-rxlev=%d\n", |
| 1389 | i, clist[i].requirements, clist[i].avg); |
| 1390 | } |
| 1391 | } |
| 1392 | |
| 1393 | #if 0 |
| 1394 | next_b1: |
| 1395 | #endif |
| 1396 | /* select best candidate that fulfills requirement B, |
| 1397 | * omit change from AHS to AFS */ |
| 1398 | best_avg_db = 0; |
| 1399 | for (i = 0; i < candidates; i++) { |
| 1400 | /* delete subscriber that just have handovered */ |
| 1401 | if (clist[i].lchan == delete_lchan) |
| 1402 | clist[i].lchan = NULL; |
| 1403 | /* omit all subscribers that are handovered */ |
| 1404 | if (!clist[i].lchan) |
| 1405 | continue; |
| 1406 | |
| 1407 | if (!(clist[i].requirements & REQUIREMENT_B_MASK)) |
| 1408 | continue; |
| 1409 | /* omit assignment from AHS to AFS */ |
| 1410 | if (clist[i].lchan->ts->trx->bts == clist[i].bts |
| 1411 | && clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1412 | && (clist[i].requirements & REQUIREMENT_B_TCHF)) |
| 1413 | continue; |
| 1414 | /* omit candidates that will not solve/reduce congestion */ |
| 1415 | if (clist[i].lchan->type == GSM_LCHAN_TCH_F |
| 1416 | && tchf_congestion <= 0) |
| 1417 | continue; |
| 1418 | if (clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1419 | && tchh_congestion <= 0) |
| 1420 | continue; |
| 1421 | |
| 1422 | avg = clist[i].avg; |
| 1423 | /* improve AHS */ |
| 1424 | if (clist[i].lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 1425 | && clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1426 | && (clist[i].requirements & REQUIREMENT_B_TCHF)) { |
| 1427 | avg += ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1428 | is_improved = 1; |
| 1429 | } else |
| 1430 | is_improved = 0; |
| 1431 | LOGP(DHODEC, LOGL_DEBUG, "candidate %d: avg=%d best_avg_db=%d\n", i, avg, best_avg_db); |
| 1432 | if (avg > best_avg_db) { |
| 1433 | best_cand = &clist[i]; |
| 1434 | best_avg_db = avg; |
| 1435 | } |
| 1436 | } |
| 1437 | |
| 1438 | /* perform handover, if there is a candidate */ |
| 1439 | if (best_cand) { |
| 1440 | any_ho = 1; |
| 1441 | LOGPHOLCHAN(best_cand->lchan, LOGL_INFO, |
| 1442 | "Best candidate BTS %u (RX level %d) without congestion found\n", |
| 1443 | best_cand->bts->nr, rxlev2dbm(best_cand->avg)); |
| 1444 | if (is_improved) |
| 1445 | LOGP(DHODEC, LOGL_INFO, "(is improved due to " |
| 1446 | "AHS -> AFS)\n"); |
| 1447 | trigger_handover_or_assignment(best_cand->lchan, best_cand->bts, |
| 1448 | best_cand->requirements & REQUIREMENT_B_MASK); |
| 1449 | #if 0 |
| 1450 | /* if there is still congestion, mark lchan as deleted |
| 1451 | * and redo this process */ |
| 1452 | if (best_cand->lchan->type == GSM_LCHAN_TCH_H) |
| 1453 | tchh_congestion--; |
| 1454 | else |
| 1455 | tchf_congestion--; |
| 1456 | if (tchf_congestion > 0 || tchh_congestion > 0) { |
| 1457 | delete_lchan = best_cand->lchan; |
| 1458 | best_cand = NULL; |
| 1459 | goto next_b1; |
| 1460 | } |
| 1461 | #else |
| 1462 | /* must exit here, because triggering handover/assignment |
| 1463 | * will cause change in requirements. more check for this |
| 1464 | * bts is performed in the next iteration. |
| 1465 | */ |
| 1466 | #endif |
| 1467 | goto exit; |
| 1468 | } |
| 1469 | |
| 1470 | LOGPHOBTS(bts, LOGL_DEBUG, "Did not find a best candidate that fulfills requirement B" |
| 1471 | " (omitting change from AHS to AFS)\n"); |
| 1472 | |
| 1473 | #if 0 |
| 1474 | next_b2: |
| 1475 | #endif |
| 1476 | /* select worst candidate that fulfills requirement B, |
| 1477 | * select candidates that change from AHS to AFS only */ |
| 1478 | if (tchh_congestion > 0) { |
| 1479 | /* since this will only check half rate channels, it will |
| 1480 | * only need to be checked, if tchh is congested */ |
| 1481 | worst_avg_db = 999; |
| 1482 | for (i = 0; i < candidates; i++) { |
| 1483 | /* delete subscriber that just have handovered */ |
| 1484 | if (clist[i].lchan == delete_lchan) |
| 1485 | clist[i].lchan = NULL; |
| 1486 | /* omit all subscribers that are handovered */ |
| 1487 | if (!clist[i].lchan) |
| 1488 | continue; |
| 1489 | |
| 1490 | if (!(clist[i].requirements & REQUIREMENT_B_MASK)) |
| 1491 | continue; |
| 1492 | /* omit all but assignment from AHS to AFS */ |
| 1493 | if (clist[i].lchan->ts->trx->bts != clist[i].bts |
| 1494 | || clist[i].lchan->type != GSM_LCHAN_TCH_H |
| 1495 | || !(clist[i].requirements & REQUIREMENT_B_TCHF)) |
| 1496 | continue; |
| 1497 | |
| 1498 | avg = clist[i].avg; |
| 1499 | /* improve AHS */ |
| 1500 | if (clist[i].lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 1501 | && clist[i].lchan->type == GSM_LCHAN_TCH_H) { |
| 1502 | avg += ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1503 | is_improved = 1; |
| 1504 | } else |
| 1505 | is_improved = 0; |
| 1506 | LOGP(DHODEC, LOGL_DEBUG, "candidate %d: avg=%d worst_avg_db=%d\n", i, avg, |
| 1507 | worst_avg_db); |
| 1508 | if (avg < worst_avg_db) { |
| 1509 | worst_cand = &clist[i]; |
| 1510 | worst_avg_db = avg; |
| 1511 | } |
| 1512 | } |
| 1513 | } |
| 1514 | |
| 1515 | /* perform handover, if there is a candidate */ |
| 1516 | if (worst_cand) { |
| 1517 | any_ho = 1; |
| 1518 | LOGP(DHODEC, LOGL_INFO, "Worst candidate for assignment " |
| 1519 | "(RX level %d) from TCH/H -> TCH/F without congestion " |
| 1520 | "found\n", rxlev2dbm(worst_cand->avg)); |
| 1521 | if (is_improved) |
| 1522 | LOGP(DHODEC, LOGL_INFO, "(is improved due to " |
| 1523 | "AHS -> AFS)\n"); |
| 1524 | trigger_handover_or_assignment(worst_cand->lchan, |
| 1525 | worst_cand->bts, |
| 1526 | worst_cand->requirements & REQUIREMENT_B_MASK); |
| 1527 | #if 0 |
| 1528 | /* if there is still congestion, mark lchan as deleted |
| 1529 | * and redo this process */ |
| 1530 | tchh_congestion--; |
| 1531 | if (tchh_congestion > 0) { |
| 1532 | delete_lchan = worst_cand->lchan; |
| 1533 | best_cand = NULL; |
| 1534 | goto next_b2; |
| 1535 | } |
| 1536 | #else |
| 1537 | /* must exit here, because triggering handover/assignment |
| 1538 | * will cause change in requirements. more check for this |
| 1539 | * bts is performed in the next iteration. |
| 1540 | */ |
| 1541 | #endif |
| 1542 | goto exit; |
| 1543 | } |
| 1544 | |
| 1545 | LOGPHOBTS(bts, LOGL_DEBUG, "Did not find a worst candidate that fulfills requirement B," |
| 1546 | " selecting candidates that change from AHS to AFS only\n"); |
| 1547 | |
| 1548 | #if 0 |
| 1549 | next_c1: |
| 1550 | #endif |
| 1551 | /* select best candidate that fulfills requirement C, |
| 1552 | * omit change from AHS to AFS */ |
| 1553 | best_avg_db = 0; |
| 1554 | for (i = 0; i < candidates; i++) { |
| 1555 | /* delete subscriber that just have handovered */ |
| 1556 | if (clist[i].lchan == delete_lchan) |
| 1557 | clist[i].lchan = NULL; |
| 1558 | /* omit all subscribers that are handovered */ |
| 1559 | if (!clist[i].lchan) |
| 1560 | continue; |
| 1561 | |
| 1562 | if (!(clist[i].requirements & REQUIREMENT_C_MASK)) |
| 1563 | continue; |
| 1564 | /* omit assignment from AHS to AFS */ |
| 1565 | if (clist[i].lchan->ts->trx->bts == clist[i].bts |
| 1566 | && clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1567 | && (clist[i].requirements & REQUIREMENT_C_TCHF)) |
| 1568 | continue; |
| 1569 | /* omit candidates that will not solve/reduce congestion */ |
| 1570 | if (clist[i].lchan->type == GSM_LCHAN_TCH_F |
| 1571 | && tchf_congestion <= 0) |
| 1572 | continue; |
| 1573 | if (clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1574 | && tchh_congestion <= 0) |
| 1575 | continue; |
| 1576 | |
| 1577 | avg = clist[i].avg; |
| 1578 | /* improve AHS */ |
| 1579 | if (clist[i].lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 1580 | && clist[i].lchan->type == GSM_LCHAN_TCH_H |
| 1581 | && (clist[i].requirements & REQUIREMENT_C_TCHF)) { |
| 1582 | avg += ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1583 | is_improved = 1; |
| 1584 | } else |
| 1585 | is_improved = 0; |
| 1586 | LOGP(DHODEC, LOGL_DEBUG, "candidate %d: avg=%d best_avg_db=%d\n", i, avg, best_avg_db); |
| 1587 | if (avg > best_avg_db) { |
| 1588 | best_cand = &clist[i]; |
| 1589 | best_avg_db = avg; |
| 1590 | } |
| 1591 | } |
| 1592 | |
| 1593 | /* perform handover, if there is a candidate */ |
| 1594 | if (best_cand) { |
| 1595 | any_ho = 1; |
| 1596 | LOGP(DHODEC, LOGL_INFO, "Best candidate BTS %d (RX level %d) " |
| 1597 | "with less or equal congestion found\n", |
| 1598 | best_cand->bts->nr, rxlev2dbm(best_cand->avg)); |
| 1599 | if (is_improved) |
| 1600 | LOGP(DHODEC, LOGL_INFO, "(is improved due to " |
| 1601 | "AHS -> AFS)\n"); |
| 1602 | trigger_handover_or_assignment(best_cand->lchan, best_cand->bts, |
| 1603 | best_cand->requirements & REQUIREMENT_C_MASK); |
| 1604 | #if 0 |
| 1605 | /* if there is still congestion, mark lchan as deleted |
| 1606 | * and redo this process */ |
| 1607 | if (best_cand->lchan->type == GSM_LCHAN_TCH_H) |
| 1608 | tchh_congestion--; |
| 1609 | else |
| 1610 | tchf_congestion--; |
| 1611 | if (tchf_congestion > 0 || tchh_congestion > 0) { |
| 1612 | delete_lchan = best_cand->lchan; |
| 1613 | best_cand = NULL; |
| 1614 | goto next_c1; |
| 1615 | } |
| 1616 | #else |
| 1617 | /* must exit here, because triggering handover/assignment |
| 1618 | * will cause change in requirements. more check for this |
| 1619 | * bts is performed in the next iteration. |
| 1620 | */ |
| 1621 | #endif |
| 1622 | goto exit; |
| 1623 | } |
| 1624 | |
| 1625 | LOGPHOBTS(bts, LOGL_DEBUG, "Did not find a best candidate that fulfills requirement C" |
| 1626 | " (omitting change from AHS to AFS)\n"); |
| 1627 | |
| 1628 | #if 0 |
| 1629 | next_c2: |
| 1630 | #endif |
| 1631 | /* select worst candidate that fulfills requirement C, |
| 1632 | * select candidates that change from AHS to AFS only */ |
| 1633 | if (tchh_congestion > 0) { |
| 1634 | /* since this will only check half rate channels, it will |
| 1635 | * only need to be checked, if tchh is congested */ |
| 1636 | worst_avg_db = 999; |
| 1637 | for (i = 0; i < candidates; i++) { |
| 1638 | /* delete subscriber that just have handovered */ |
| 1639 | if (clist[i].lchan == delete_lchan) |
| 1640 | clist[i].lchan = NULL; |
| 1641 | /* omit all subscribers that are handovered */ |
| 1642 | if (!clist[i].lchan) |
| 1643 | continue; |
| 1644 | |
| 1645 | if (!(clist[i].requirements & REQUIREMENT_C_MASK)) |
| 1646 | continue; |
| 1647 | /* omit all but assignment from AHS to AFS */ |
| 1648 | if (clist[i].lchan->ts->trx->bts != clist[i].bts |
| 1649 | || clist[i].lchan->type != GSM_LCHAN_TCH_H |
| 1650 | || !(clist[i].requirements & REQUIREMENT_C_TCHF)) |
| 1651 | continue; |
| 1652 | |
| 1653 | avg = clist[i].avg; |
| 1654 | /* improve AHS */ |
| 1655 | if (clist[i].lchan->tch_mode == GSM48_CMODE_SPEECH_AMR |
| 1656 | && clist[i].lchan->type == GSM_LCHAN_TCH_H) { |
| 1657 | avg += ho_get_hodec2_afs_bias_rxlev(clist[i].bts->ho); |
| 1658 | is_improved = 1; |
| 1659 | } else |
| 1660 | is_improved = 0; |
| 1661 | LOGP(DHODEC, LOGL_DEBUG, "candidate %d: avg=%d worst_avg_db=%d\n", i, avg, |
| 1662 | worst_avg_db); |
| 1663 | if (avg < worst_avg_db) { |
| 1664 | worst_cand = &clist[i]; |
| 1665 | worst_avg_db = avg; |
| 1666 | } |
| 1667 | } |
| 1668 | } |
| 1669 | |
| 1670 | /* perform handover, if there is a candidate */ |
| 1671 | if (worst_cand) { |
| 1672 | any_ho = 1; |
| 1673 | LOGP(DHODEC, LOGL_INFO, "Worst candidate for assignment " |
| 1674 | "(RX level %d) from TCH/H -> TCH/F with less or equal " |
| 1675 | "congestion found\n", rxlev2dbm(worst_cand->avg)); |
| 1676 | if (is_improved) |
| 1677 | LOGP(DHODEC, LOGL_INFO, "(is improved due to " |
| 1678 | "AHS -> AFS)\n"); |
| 1679 | trigger_handover_or_assignment(worst_cand->lchan, |
| 1680 | worst_cand->bts, |
| 1681 | worst_cand->requirements & REQUIREMENT_C_MASK); |
| 1682 | #if 0 |
| 1683 | /* if there is still congestion, mark lchan as deleted |
| 1684 | * and redo this process */ |
| 1685 | tchh_congestion--; |
| 1686 | if (tchh_congestion > 0) { |
| 1687 | delete_lchan = worst_cand->lchan; |
| 1688 | worst_cand = NULL; |
| 1689 | goto next_c2; |
| 1690 | } |
| 1691 | #else |
| 1692 | /* must exit here, because triggering handover/assignment |
| 1693 | * will cause change in requirements. more check for this |
| 1694 | * bts is performed in the next iteration. |
| 1695 | */ |
| 1696 | #endif |
| 1697 | goto exit; |
| 1698 | } |
| 1699 | LOGPHOBTS(bts, LOGL_DEBUG, "Did not find a worst candidate that fulfills requirement C," |
| 1700 | " selecting candidates that change from AHS to AFS only\n"); |
| 1701 | |
| 1702 | |
| 1703 | exit: |
| 1704 | /* free array */ |
| 1705 | talloc_free(clist); |
| 1706 | |
| 1707 | if (tchf_congestion <= 0 && tchh_congestion <= 0) |
| 1708 | LOGP(DHODEC, LOGL_INFO, "Congestion at BTS %d solved!\n", |
| 1709 | bts->nr); |
| 1710 | else if (any_ho) |
| 1711 | LOGP(DHODEC, LOGL_INFO, "Congestion at BTS %d reduced!\n", |
| 1712 | bts->nr); |
| 1713 | else |
| 1714 | LOGP(DHODEC, LOGL_INFO, "Congestion at BTS %d can't be reduced/solved!\n", bts->nr); |
| 1715 | |
| 1716 | return rc; |
| 1717 | } |
| 1718 | |
| 1719 | static void bts_congestion_check(struct gsm_bts *bts) |
| 1720 | { |
| 1721 | int min_free_tchf, min_free_tchh; |
| 1722 | int tchf_count, tchh_count; |
| 1723 | |
| 1724 | global_ho_reason = HO_REASON_CONGESTION; |
| 1725 | |
| 1726 | /* only check BTS if TRX 0 is usable */ |
| 1727 | if (!trx_is_usable(bts->c0)) { |
| 1728 | LOGPHOBTS(bts, LOGL_DEBUG, "No congestion check: TRX 0 not usable\n"); |
| 1729 | return; |
| 1730 | } |
| 1731 | |
| 1732 | /* only check BTS if handover or assignment is enabled */ |
| 1733 | if (!ho_get_hodec2_as_active(bts->ho) |
| 1734 | && !ho_get_ho_active(bts->ho)) { |
| 1735 | LOGPHOBTS(bts, LOGL_DEBUG, "No congestion check: Assignment and Handover both disabled\n"); |
| 1736 | return; |
| 1737 | } |
| 1738 | |
| 1739 | min_free_tchf = ho_get_hodec2_tchf_min_slots(bts->ho); |
| 1740 | min_free_tchh = ho_get_hodec2_tchh_min_slots(bts->ho); |
| 1741 | |
| 1742 | /* only check BTS with congestion level set */ |
| 1743 | if (!min_free_tchf && !min_free_tchh) { |
| 1744 | LOGPHOBTS(bts, LOGL_DEBUG, "No congestion check: no minimum for free TCH/F nor TCH/H set\n"); |
| 1745 | return; |
| 1746 | } |
| 1747 | |
| 1748 | tchf_count = bts_count_free_ts(bts, GSM_PCHAN_TCH_F); |
| 1749 | tchh_count = bts_count_free_ts(bts, GSM_PCHAN_TCH_H); |
| 1750 | LOGPHOBTS(bts, LOGL_INFO, "Congestion check: (free/want-free) TCH/F=%d/%d TCH/H=%d/%d\n", |
| 1751 | tchf_count, min_free_tchf, tchh_count, min_free_tchh); |
| 1752 | |
| 1753 | /* only check BTS if congested */ |
| 1754 | if (tchf_count >= min_free_tchf && tchh_count >= min_free_tchh) { |
| 1755 | LOGPHOBTS(bts, LOGL_DEBUG, "Not congested\n"); |
| 1756 | return; |
| 1757 | } |
| 1758 | |
| 1759 | LOGPHOBTS(bts, LOGL_DEBUG, "Attempting to resolve congestion...\n"); |
| 1760 | bts_resolve_congestion(bts, min_free_tchf - tchf_count, min_free_tchh - tchh_count); |
| 1761 | } |
| 1762 | |
| 1763 | void hodec2_congestion_check(struct gsm_network *net) |
| 1764 | { |
| 1765 | struct gsm_bts *bts; |
| 1766 | |
| 1767 | llist_for_each_entry(bts, &net->bts_list, list) |
| 1768 | bts_congestion_check(bts); |
| 1769 | } |
| 1770 | |
| 1771 | static void congestion_check_cb(void *arg) |
| 1772 | { |
| 1773 | struct gsm_network *net = arg; |
| 1774 | hodec2_congestion_check(net); |
| 1775 | reinit_congestion_timer(net); |
| 1776 | } |
| 1777 | |
| 1778 | void on_ho_chan_activ_nack(struct bsc_handover *ho) |
| 1779 | { |
| 1780 | struct gsm_bts *new_bts = ho->new_lchan->ts->trx->bts; |
| 1781 | |
| 1782 | LOGPHO(ho, LOGL_ERROR, "Channel Activate Nack for %s, starting penalty timer\n", ho->inter_cell? "Handover" : "Assignment"); |
| 1783 | |
| 1784 | /* if channel failed, wait 10 seconds before allowing to retry handover */ |
| 1785 | conn_penalty_time_add(ho->old_lchan->conn, new_bts, 10); /* FIXME configurable */ |
| 1786 | } |
| 1787 | |
| 1788 | void on_ho_failure(struct bsc_handover *ho) |
| 1789 | { |
| 1790 | struct gsm_bts *old_bts = ho->old_lchan->ts->trx->bts; |
| 1791 | struct gsm_bts *new_bts = ho->new_lchan->ts->trx->bts; |
| 1792 | struct gsm_subscriber_connection *conn = ho->old_lchan->conn; |
| 1793 | |
| 1794 | if (!conn) { |
| 1795 | LOGPHO(ho, LOGL_ERROR, "HO failure, but no conn"); |
| 1796 | return; |
| 1797 | } |
| 1798 | |
| 1799 | if (conn->hodec2.failures >= ho_get_hodec2_retries(old_bts->ho)) { |
| 1800 | int penalty = ho->inter_cell |
| 1801 | ? ho_get_hodec2_penalty_failed_ho(old_bts->ho) |
| 1802 | : ho_get_hodec2_penalty_failed_as(old_bts->ho); |
| 1803 | LOGPHO(ho, LOGL_NOTICE, "%s failed, starting penalty timer (%d s)\n", |
| 1804 | ho->inter_cell ? "Handover" : "Assignment", |
| 1805 | penalty); |
| 1806 | conn->hodec2.failures = 0; |
| 1807 | conn_penalty_time_add(conn, new_bts, penalty); |
| 1808 | } else { |
| 1809 | conn->hodec2.failures++; |
| 1810 | LOGPHO(ho, LOGL_NOTICE, "%s failed, allowing handover decision to try again" |
| 1811 | " (%d/%d attempts)\n", |
| 1812 | ho->inter_cell ? "Handover" : "Assignment", |
| 1813 | conn->hodec2.failures, ho_get_hodec2_retries(old_bts->ho)); |
| 1814 | } |
| 1815 | } |
| 1816 | |
| 1817 | struct handover_decision_callbacks hodec2_callbacks = { |
| 1818 | .hodec_id = 2, |
| 1819 | .on_measurement_report = on_measurement_report, |
| 1820 | .on_ho_chan_activ_nack = on_ho_chan_activ_nack, |
| 1821 | .on_ho_failure = on_ho_failure, |
| 1822 | }; |
| 1823 | |
| 1824 | void hodec2_init(struct gsm_network *net) |
| 1825 | { |
| 1826 | handover_decision_callbacks_register(&hodec2_callbacks); |
| 1827 | hodec2_initialized = true; |
| 1828 | reinit_congestion_timer(net); |
| 1829 | } |