FACCH9 channel coding

Files
file	facch9.h
	Osmocom GMR-1 FACCH9 channel coding header.
file	facch9.c
	Osmocom GMR-1 FACCH9 channel coding implementation.

Functions
void	gmr1_facch9_encode (ubit_t *bits_e, const uint8_t *l2, const ubit_t *bits_sacch, const ubit_t *bits_status, const ubit_t *ciph)
	Stateless GMR-1 FACCH9 channel coder. More...
int	gmr1_facch9_decode (uint8_t *l2, sbit_t *bits_sacch, sbit_t *bits_status, const sbit_t *bits_e, const ubit_t *ciph, int *conv_rv)
	Stateless GMR-1 FACCH9 channel decoder. More...

Detailed Description

Function Documentation

gmr1_facch9_decode()

int gmr1_facch9_decode	(	uint8_t *	l2,
		sbit_t *	bits_sacch,
		sbit_t *	bits_status,
		const sbit_t *	bits_e,
		const ubit_t *	ciph,
		int *	conv_rv
	)

Stateless GMR-1 FACCH9 channel decoder.

Parameters

[out]	l2	L2 packet data (38 bytes, last nibble unused)
[out]	bits_sacch	10 saach bits demultiplexed
[out]	bits_status	4 status bits demultiplexed
[in]	bits_e	662 encoded bits of one NT9 burst
[in]	ciph	658 bits of cipher stream (can be NULL)
[out]	conv_rv	Return of the convolutional decode (can be NULL)

Returns

0 if CRC check pass, any other value for fail.

References gmr1_deinterleave_intra(), gmr1_scramble_sbit(), and osmo_conv_decode().

gmr1_facch9_encode()

void gmr1_facch9_encode	(	ubit_t *	bits_e,
		const uint8_t *	l2,
		const ubit_t *	bits_sacch,
		const ubit_t *	bits_status,
		const ubit_t *	ciph
	)

Stateless GMR-1 FACCH9 channel coder.

Parameters

[out]	bits_e	662 encoded bits of one NT9 burst
[in]	l2	L2 packet data (38 bytes, last nibble unused)
[in]	bits_sacch	10 saach bits to be multiplexed
[in]	bits_status	4 status bits to be multiplexed
[in]	ciph	658 bits of cipher stream (can be NULL)

References gmr1_crc16, osmo_conv_encode(), osmo_crc16gen_set_bits(), and osmo_pbit2ubit_ext().