gsm0502.h

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#pragma once
 
#include <stdint.h>
 
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
 
/* 4.3.3 TDMA frame number : constants and modular arithmetic */
#define GSM_TDMA_FN_DURATION_nS         4615384         /* in 1e−9 seconds (approx) */
#define GSM_TDMA_FN_DURATION_uS         4615            /* in 1e-6 seconds (approx) */
 
#define GSM_TDMA_SUPERFRAME             (26 * 51)
#define GSM_TDMA_HYPERFRAME             (2048 * GSM_TDMA_SUPERFRAME)
 
#define GSM_TDMA_FN_SUM(a, b) \
        (((a) + (b)) % GSM_TDMA_HYPERFRAME)
#define GSM_TDMA_FN_SUB(a, b) \
        (((a) + GSM_TDMA_HYPERFRAME - (b)) % GSM_TDMA_HYPERFRAME)
#define GSM_TDMA_FN_DIFF(a, b) \
        OSMO_MIN(GSM_TDMA_FN_SUB(a, b), GSM_TDMA_FN_SUB(b, a))
 
#define GSM_TDMA_FN_INC(fn) \
        ((fn) = GSM_TDMA_FN_SUM((fn), 1))
#define GSM_TDMA_FN_DEC(fn) \
        ((fn) = GSM_TDMA_FN_SUB((fn), 1))
 
/* 5.2.3.1 Normal burst for GMSK (1 bit per symbol) */
#define GSM_NBITS_NB_GMSK_TAIL          3
#define GSM_NBITS_NB_GMSK_PAYLOAD       (2 * 58)
#define GSM_NBITS_NB_GMSK_TRAIN_SEQ     26
#define GSM_NBITS_NB_GMSK_BURST         148  /* without guard period */
 
/* 5.2.3.3 Normal burst for 8-PSK (3 bits per symbol) */
#define GSM_NBITS_NB_8PSK_TAIL          (GSM_NBITS_NB_GMSK_TAIL * 3)
#define GSM_NBITS_NB_8PSK_PAYLOAD       (GSM_NBITS_NB_GMSK_PAYLOAD * 3)
#define GSM_NBITS_NB_8PSK_TRAIN_SEQ     (GSM_NBITS_NB_GMSK_TRAIN_SEQ * 3)
#define GSM_NBITS_NB_8PSK_BURST         (GSM_NBITS_NB_GMSK_BURST * 3)
 
/* 5.2.5 Synchronization burst (also GMSK) */
#define GSM_NBITS_SB_GMSK_TAIL          GSM_NBITS_NB_GMSK_TAIL
#define GSM_NBITS_SB_GMSK_PAYLOAD       (2 * 39)
#define GSM_NBITS_SB_GMSK_ETRAIN_SEQ    64
#define GSM_NBITS_SB_GMSK_BURST         GSM_NBITS_NB_GMSK_BURST
 
/* 5.2.6 Dummy burst (also GMSK) */
#define GSM_NBITS_DB_GMSK_TAIL          GSM_NBITS_NB_GMSK_TAIL
#define GSM_NBITS_DB_GMSK_MIXED         142
#define GSM_NBITS_DB_GMSK_BURST         GSM_NBITS_NB_GMSK_BURST
 
/* 5.2.7 Access burst (also GMSK) */
#define GSM_NBITS_AB_GMSK_ETAIL         8
#define GSM_NBITS_AB_GMSK_SYNCH_SEQ     41
#define GSM_NBITS_AB_GMSK_PAYLOAD       36
#define GSM_NBITS_AB_GMSK_TAIL          GSM_NBITS_NB_GMSK_TAIL
#define GSM_NBITS_AB_GMSK_BURST         GSM_NBITS_NB_GMSK_BURST
 
static inline int gsm0502_fncmp(uint32_t fn1, uint32_t fn2)
{
        const uint32_t thresh = GSM_TDMA_HYPERFRAME / 2;
 
        if (fn1 == fn2)
                return 0;
        if ((fn1 < fn2 && (fn2 - fn1) < thresh) ||
            (fn1 > fn2 && (fn1 - fn2) > thresh))
                return -1;
 
        return 1;
}
 
/* Table 5 Clause 7 TS 05.02 */
static inline unsigned int
gsm0502_get_n_pag_blocks(const struct gsm48_control_channel_descr *chan_desc)
{
        if (chan_desc->ccch_conf == RSL_BCCH_CCCH_CONF_1_C)
                return 3 - chan_desc->bs_ag_blks_res;
        else
                return 9 - chan_desc->bs_ag_blks_res;
}
 
/* Chapter 6.5.2 of TS 05.02 */
static inline unsigned int
gsm0502_get_ccch_group(uint64_t imsi, unsigned int bs_cc_chans,
                        unsigned int n_pag_blocks)
{
        return (imsi % 1000) % (bs_cc_chans * n_pag_blocks) / n_pag_blocks;
}
 
/* Chapter 6.5.2 of TS 05.02 */
static inline unsigned int
gsm0502_get_paging_group(uint64_t imsi, unsigned int bs_cc_chans,
                         int n_pag_blocks)
{
        return (imsi % 1000) % (bs_cc_chans * n_pag_blocks) % n_pag_blocks;
}
 
unsigned int
gsm0502_calc_paging_group(const struct gsm48_control_channel_descr *chan_desc, uint64_t imsi);
 
enum gsm0502_fn_remap_channel {
        FN_REMAP_TCH_F,
        FN_REMAP_TCH_H0,
        FN_REMAP_TCH_H1,
        FN_REMAP_FACCH_F,
        FN_REMAP_FACCH_H0,
        FN_REMAP_FACCH_H1,
        FN_REMAP_MAX,
};
 
uint32_t gsm0502_fn_remap(uint32_t fn, enum gsm0502_fn_remap_channel channel);
 
uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t,
                             uint8_t hsn, uint8_t maio,
                             size_t n, const uint16_t *ma);
 
int gsm0502_fn2ccch_block(uint32_t fn);