diff options
Diffstat (limited to 'src/gsm/gsm0502.c')
| -rw-r--r-- | src/gsm/gsm0502.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/src/gsm/gsm0502.c b/src/gsm/gsm0502.c index e34d3f57..e4a761da 100644 --- a/src/gsm/gsm0502.c +++ b/src/gsm/gsm0502.c @@ -34,7 +34,7 @@ #include <inttypes.h> unsigned int -gsm0502_calc_paging_group(struct gsm48_control_channel_descr *chan_desc, uint64_t imsi) +gsm0502_calc_paging_group(const struct gsm48_control_channel_descr *chan_desc, uint64_t imsi) { int ccch_conf; int bs_cc_chans; @@ -179,7 +179,6 @@ uint32_t gsm0502_fn_remap(uint32_t fn, enum gsm0502_fn_remap_channel channel) uint8_t fn_cycle; uint8_t i; int sub = -1; - uint32_t fn_map; struct fn_remap_table *table; OSMO_ASSERT(channel < ARRAY_SIZE(fn_remap_table_ptr)); @@ -199,9 +198,7 @@ uint32_t gsm0502_fn_remap(uint32_t fn, enum gsm0502_fn_remap_channel channel) return fn; } - fn_map = (fn + GSM_MAX_FN - sub) % GSM_MAX_FN; - - return fn_map; + return GSM_TDMA_FN_SUB(fn, sub); } /* Magic numbers (RNTABLE) for pseudo-random hopping sequence generation. */ @@ -263,3 +260,38 @@ uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t, return ma ? ma[mai] : mai; } + +#define CB_FCCH -1 +#define CB_SCH -2 +#define CB_BCCH -3 +#define CB_IDLE -4 + +/* Clause 7 Table 3 and Figure 8a */ +static const int ccch_block_table[51] = { + CB_FCCH, CB_SCH, /* 0..1 */ + CB_BCCH, CB_BCCH, CB_BCCH, CB_BCCH, /* 2..5: BCCH */ + 0, 0, 0, 0, /* 6..9: B0 */ + CB_FCCH, CB_SCH, /* 10..11 */ + 1, 1, 1, 1, /* 12..15: B1 */ + 2, 2, 2, 2, /* 16..19: B2 */ + CB_FCCH, CB_SCH, /* 20..21 */ + 3, 3, 3, 3, /* 22..25: B3 */ + 4, 4, 4, 4, /* 26..29: B4 */ + CB_FCCH, CB_SCH, /* 30..31 */ + 5, 5, 5, 5, /* 32..35: B5 */ + 6, 6, 6, 6, /* 36..39: B6 */ + CB_FCCH, CB_SCH, /* 40..41 */ + 7, 7, 7, 7, /* 42..45: B7 */ + 8, 8, 8, 8, /* 46..49: B8 */ + CB_IDLE /* 50: Idle */ +}; + +/*! Calculate CCCH block number from the given TDMA frame number. + * \param[in] fn TDMA frame number (of first or last burst). + * \returns CCCH block number 0..8 or a negative value, + * if the given frame number cannot carry CCCH. + */ +int gsm0502_fn2ccch_block(uint32_t fn) +{ + return ccch_block_table[fn % ARRAY_SIZE(ccch_block_table)]; +} |