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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>
This commit is contained in:
Sylvain Munaut 2009-12-22 13:43:26 +01:00 committed by Harald Welte
parent ff1f19e199
commit 4010f1e6f4
4 changed files with 43 additions and 5 deletions
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7
openbsc/include/openbsc/gsm_utils.h
View File

@ -37,5 +37,12 @@ int ms_pwr_dbm(enum gsm_band band, u_int8_t lvl);
int rxlev2dbm(u_int8_t rxlev);
u_int8_t dbm2rxlev(int dbm);
/* According to GSM 04.08 Chapter 10.5.2.29 */
static inline int rach_max_trans_val2raw(int val) { return (val >> 1) & 3; }
static inline int rach_max_trans_raw2val(int raw) {
const int tbl[4] = { 1, 2, 4, 7 };
return tbl[raw & 3];
}
void generate_backtrace();
#endif

5
openbsc/src/bsc_init.c
View File

@ -823,11 +823,6 @@ static int bootstrap_bts(struct gsm_bts *bts)
/* T3212 is set from vty/config */
/* some defaults for our system information */
bts->si_common.rach_control.re = 1; /* no re-establishment */
bts->si_common.rach_control.tx_integer = 5; /* 8 slots spread */
bts->si_common.rach_control.max_trans = 3; /* 7 retransmissions */
bts->si_common.rach_control.t2 = 4; /* no emergency calls */
bts->si_common.cell_options.radio_link_timeout = 2; /* 12 */
bts->si_common.cell_options.dtx = 2; /* MS shall not use upplink DTX */
bts->si_common.cell_options.pwrc = 0; /* PWRC not set */

4
openbsc/src/gsm_data.c
View File

@ -175,6 +175,10 @@ struct gsm_bts *gsm_bts_alloc(struct gsm_network *net, enum gsm_bts_type type,
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;

32
openbsc/src/vty_interface.c
View File

@ -168,6 +168,11 @@ static void bts_dump_vty(struct vty *vty, struct gsm_bts *bts)
VTY_NEWLINE);
vty_out(vty, "Cell Reselection Hysteresis: %u dBm%s",
bts->si_common.cell_sel_par.cell_resel_hyst*2, VTY_NEWLINE);
vty_out(vty, "RACH TX-Integer: %u%s", bts->si_common.rach_control.tx_integer,
VTY_NEWLINE);
vty_out(vty, "RACH Max transmissions: %u%s",
rach_max_trans_raw2val(bts->si_common.rach_control.max_trans),
VTY_NEWLINE);
if (bts->si_common.rach_control.cell_bar)
vty_out(vty, " CELL IS BARRED%s", VTY_NEWLINE);
if (is_ipaccess_bts(bts))
@ -290,6 +295,11 @@ static void config_write_bts_single(struct vty *vty, struct gsm_bts *bts)
vty_out(vty, " channel allocator %s%s",
bts->chan_alloc_reverse ? "descending" : "ascending",
VTY_NEWLINE);
vty_out(vty, " rach tx integer %u%s",
bts->si_common.rach_control.tx_integer, VTY_NEWLINE);
vty_out(vty, " rach max transmission %u%s",
rach_max_trans_raw2val(bts->si_common.rach_control.max_trans),
VTY_NEWLINE);
if (bts->si_common.rach_control.cell_bar)
vty_out(vty, " cell barred 1%s", VTY_NEWLINE);
if (is_ipaccess_bts(bts)) {
@ -1263,6 +1273,26 @@ DEFUN(cfg_bts_challoc, cfg_bts_challoc_cmd,
return CMD_SUCCESS;
}
DEFUN(cfg_bts_rach_tx_integer,
cfg_bts_rach_tx_integer_cmd,
"rach tx integer <0-15>",
"Set the raw tx integer value in RACH Control parameters IE")
{
struct gsm_bts *bts = vty->index;
bts->si_common.rach_control.tx_integer = atoi(argv[0]) & 0xf;
return CMD_SUCCESS;
}
DEFUN(cfg_bts_rach_max_trans,
cfg_bts_rach_max_trans_cmd,
"rach max transmission (1|2|4|7)",
"Set the maximum number of RACH burst transmissions")
{
struct gsm_bts *bts = vty->index;
bts->si_common.rach_control.max_trans = rach_max_trans_val2raw(atoi(argv[0]));
return CMD_SUCCESS;
}
DEFUN(cfg_bts_cell_barred, cfg_bts_cell_barred_cmd,
"cell barred (0|1)",
"Should this cell be barred from access?")
@ -1550,6 +1580,8 @@ int bsc_vty_init(struct gsm_network *net)
install_element(BTS_NODE, &cfg_bts_oml_e1_cmd);
install_element(BTS_NODE, &cfg_bts_oml_e1_tei_cmd);
install_element(BTS_NODE, &cfg_bts_challoc_cmd);
install_element(BTS_NODE, &cfg_bts_rach_tx_integer_cmd);
install_element(BTS_NODE, &cfg_bts_rach_max_trans_cmd);
install_element(BTS_NODE, &cfg_bts_cell_barred_cmd);
install_element(BTS_NODE, &cfg_bts_ms_max_power_cmd);
install_element(BTS_NODE, &cfg_bts_per_loc_upd_cmd);