Convolutional encoding and decoding routines

Osmocom convolutional encoder and decoder. More...

Files
file	conv.h
	Osmocom convolutional encoder and decoder.
file	conv.c
	Generic convolutional encoding / decoding.

Data Structures
struct	osmo_conv_code
	structure describing a given convolutional code More...
struct	osmo_conv_encoder
	convolutional encoder state More...
struct	osmo_conv_decoder
	convolutional decoder state More...

Macros
#define	MAX_AE   0x00ffffff

Enumerations
enum	osmo_conv_term {   CONV_TERM_FLUSH = 0 ,   CONV_TERM_TRUNCATION ,   CONV_TERM_TAIL_BITING }
	possibe termination types More...

Functions
int	osmo_conv_get_input_length (const struct osmo_conv_code *code, int len)
int	osmo_conv_get_output_length (const struct osmo_conv_code *code, int len)
void	osmo_conv_encode_init (struct osmo_conv_encoder *encoder, const struct osmo_conv_code *code)
	Initialize a convolutional encoder. More...
void	osmo_conv_encode_load_state (struct osmo_conv_encoder *encoder, const ubit_t *input)
int	osmo_conv_encode_raw (struct osmo_conv_encoder *encoder, const ubit_t *input, ubit_t *output, int n)
int	osmo_conv_encode_flush (struct osmo_conv_encoder *encoder, ubit_t *output)
int	osmo_conv_encode (const struct osmo_conv_code *code, const ubit_t *input, ubit_t *output)
	All-in-one convolutional encoding function. More...
void	osmo_conv_decode_init (struct osmo_conv_decoder *decoder, const struct osmo_conv_code *code, int len, int start_state)
void	osmo_conv_decode_reset (struct osmo_conv_decoder *decoder, int start_state)
void	osmo_conv_decode_rewind (struct osmo_conv_decoder *decoder)
void	osmo_conv_decode_deinit (struct osmo_conv_decoder *decoder)
int	osmo_conv_decode_scan (struct osmo_conv_decoder *decoder, const sbit_t *input, int n)
int	osmo_conv_decode_flush (struct osmo_conv_decoder *decoder, const sbit_t *input)
int	osmo_conv_decode_get_best_end_state (struct osmo_conv_decoder *decoder)
int	osmo_conv_decode_get_output (struct osmo_conv_decoder *decoder, ubit_t *output, int has_flush, int end_state)
int	osmo_conv_decode (const struct osmo_conv_code *code, const sbit_t *input, ubit_t *output)
	All-in-one convolutional decoding function. More...
static int	_conv_encode_do_output (struct osmo_conv_encoder *encoder, uint8_t out, ubit_t *output)
int	osmo_conv_decode_acc (const struct osmo_conv_code *code, const sbit_t *input, ubit_t *output)

Detailed Description

Osmocom convolutional encoder and decoder.

Macro Definition Documentation

MAX_AE

#define MAX_AE   0x00ffffff

Enumeration Type Documentation

osmo_conv_term

enum osmo_conv_term

possibe termination types

The termination type will determine which state the encoder/decoder can start/end with. This is mostly taken care of in the high level API call. So if you use the low level API, you must take care of making the proper calls yourself.

Enumerator
CONV_TERM_FLUSH	Flush encoder state.
CONV_TERM_TRUNCATION	Direct truncation.
CONV_TERM_TAIL_BITING	Tail biting.

Function Documentation

_conv_encode_do_output()

static int _conv_encode_do_output ( struct osmo_conv_encoder *  encoder, uint8_t  out, ubit_t *  output  )

inlinestatic

References osmo_conv_encoder::code, osmo_conv_encoder::i_idx, osmo_conv_code::N, osmo_conv_encoder::p_idx, and osmo_conv_code::puncture.

Referenced by osmo_conv_encode_flush(), and osmo_conv_encode_raw().

osmo_conv_decode()

int osmo_conv_decode	(	const struct osmo_conv_code *	code,
		const sbit_t *	input,
		ubit_t *	output
	)

All-in-one convolutional decoding function.

Parameters

[in]	code	description of convolutional code to be used
[in]	input	array of soft bits (coded)
[out]	output	array of unpacked bits (decoded)

This is an all-in-one function, taking care of osmo_conv_decode_init, osmo_conv_decode_scan, osmo_conv_decode_flush, osmo_conv_decode_get_best_end_state, osmo_conv_decode_get_output and osmo_conv_decode_deinit.

References osmo_conv_decoder::code, CONV_TERM_FLUSH, CONV_TERM_TAIL_BITING, osmo_conv_code::K, l, osmo_conv_code::len, osmo_conv_code::N, osmo_conv_decode_acc(), osmo_conv_decode_deinit(), osmo_conv_decode_flush(), osmo_conv_decode_get_output(), osmo_conv_decode_init(), osmo_conv_decode_rewind(), osmo_conv_decode_scan(), and osmo_conv_code::term.

osmo_conv_decode_acc()

int osmo_conv_decode_acc	(	const struct osmo_conv_code *	code,
		const sbit_t *	input,
		ubit_t *	output
	)

References conv_decode(), init_complete, osmo_conv_code::K, osmo_conv_code::len, osmo_conv_code::N, osmo_conv_init(), osmo_conv_code::puncture, osmo_conv_code::term, vdec_deinit(), and vdec_init().

Referenced by osmo_conv_decode().

osmo_conv_decode_deinit()

void osmo_conv_decode_deinit

(

struct osmo_conv_decoder *

decoder

)

References osmo_conv_decoder::ae, osmo_conv_decoder::ae_next, and osmo_conv_decoder::state_history.

Referenced by osmo_conv_decode().

osmo_conv_decode_flush()

int osmo_conv_decode_flush	(	struct osmo_conv_decoder *	decoder,
		const sbit_t *	input
	)

References osmo_conv_decoder::ae, osmo_conv_decoder::ae_next, osmo_conv_decoder::code, osmo_conv_code::K, MAX_AE, osmo_conv_code::N, osmo_conv_decoder::n_states, osmo_conv_code::next_output, osmo_conv_code::next_state, osmo_conv_code::next_term_output, osmo_conv_code::next_term_state, osmo_conv_decoder::o_idx, osmo_conv_decoder::p_idx, osmo_conv_code::puncture, and osmo_conv_decoder::state_history.

Referenced by osmo_conv_decode().

osmo_conv_decode_get_best_end_state()

int osmo_conv_decode_get_best_end_state

(

struct osmo_conv_decoder *

decoder

)

References osmo_conv_decoder::ae, osmo_conv_decoder::code, CONV_TERM_FLUSH, CONV_TERM_TAIL_BITING, MAX_AE, n, osmo_conv_decoder::n_states, osmo_conv_decoder::o_idx, osmo_conv_decoder::state_history, and osmo_conv_code::term.

Referenced by osmo_conv_decode_get_output().

osmo_conv_decode_get_output()

int osmo_conv_decode_get_output	(	struct osmo_conv_decoder *	decoder,
		ubit_t *	output,
		int	has_flush,
		int	end_state
	)

References osmo_conv_decoder::ae, osmo_conv_decoder::code, osmo_conv_code::K, n, osmo_conv_decoder::n_states, osmo_conv_code::next_state, osmo_conv_decoder::o_idx, osmo_conv_decode_get_best_end_state(), and osmo_conv_decoder::state_history.

Referenced by osmo_conv_decode().

osmo_conv_decode_init()

void osmo_conv_decode_init	(	struct osmo_conv_decoder *	decoder,
		const struct osmo_conv_code *	code,
		int	len,
		int	start_state
	)

References osmo_conv_decoder::ae, osmo_conv_decoder::ae_next, osmo_conv_encoder::code, osmo_conv_decoder::code, osmo_conv_code::K, len(), osmo_conv_code::len, osmo_conv_decoder::len, osmo_conv_decoder::n_states, osmo_conv_decode_reset(), and osmo_conv_decoder::state_history.

Referenced by osmo_conv_decode().

osmo_conv_decode_reset()

void osmo_conv_decode_reset	(	struct osmo_conv_decoder *	decoder,
		int	start_state
	)

References osmo_conv_decoder::ae, MAX_AE, osmo_conv_decoder::n_states, osmo_conv_decoder::o_idx, and osmo_conv_decoder::p_idx.

Referenced by osmo_conv_decode_init().

osmo_conv_decode_rewind()

void osmo_conv_decode_rewind

(

struct osmo_conv_decoder *

decoder

)

References osmo_conv_decoder::ae, MAX_AE, osmo_conv_decoder::n_states, osmo_conv_decoder::o_idx, and osmo_conv_decoder::p_idx.

Referenced by osmo_conv_decode().

osmo_conv_decode_scan()

int osmo_conv_decode_scan	(	struct osmo_conv_decoder *	decoder,
		const sbit_t *	input,
		int	n
	)

References osmo_conv_decoder::ae, osmo_conv_decoder::ae_next, osmo_conv_decoder::code, MAX_AE, n, osmo_conv_code::N, osmo_conv_decoder::n_states, osmo_conv_code::next_output, osmo_conv_code::next_state, osmo_conv_decoder::o_idx, osmo_conv_decoder::p_idx, osmo_conv_code::puncture, and osmo_conv_decoder::state_history.

Referenced by osmo_conv_decode().

osmo_conv_encode()

int osmo_conv_encode	(	const struct osmo_conv_code *	code,
		const ubit_t *	input,
		ubit_t *	output
	)

All-in-one convolutional encoding function.

Parameters

[in]	code	description of convolutional code to be used
[in]	input	array of unpacked bits (uncoded)
[out]	output	array of unpacked bits (encoded)

Returns

Number of produced output bits

This is an all-in-one function, taking care of osmo_conv_init, osmo_conv_encode_load_state, osmo_conv_encode_raw and osmo_conv_encode_flush as needed.

References osmo_conv_encoder::code, CONV_TERM_FLUSH, CONV_TERM_TAIL_BITING, osmo_conv_code::K, l, osmo_conv_code::len, osmo_conv_encode_flush(), osmo_conv_encode_init(), osmo_conv_encode_load_state(), osmo_conv_encode_raw(), and osmo_conv_code::term.

osmo_conv_encode_flush()

int osmo_conv_encode_flush	(	struct osmo_conv_encoder *	encoder,
		ubit_t *	output
	)

References _conv_encode_do_output(), osmo_conv_encoder::code, osmo_conv_encoder::i_idx, osmo_conv_code::K, n, osmo_conv_code::next_output, osmo_conv_code::next_state, osmo_conv_code::next_term_output, osmo_conv_code::next_term_state, and osmo_conv_encoder::state.

Referenced by osmo_conv_encode().

osmo_conv_encode_init()

void osmo_conv_encode_init	(	struct osmo_conv_encoder *	encoder,
		const struct osmo_conv_code *	code
	)

Initialize a convolutional encoder.

Parameters

[in,out]	encoder	Encoder state to initialize
[in]	code	Description of convolutional code

References osmo_conv_encoder::code, and OSMO_ASSERT.

Referenced by osmo_conv_encode().

osmo_conv_encode_load_state()

void osmo_conv_encode_load_state	(	struct osmo_conv_encoder *	encoder,
		const ubit_t *	input
	)

References osmo_conv_encoder::code, osmo_conv_code::K, and osmo_conv_encoder::state.

Referenced by osmo_conv_encode().

osmo_conv_encode_raw()

int osmo_conv_encode_raw	(	struct osmo_conv_encoder *	encoder,
		const ubit_t *	input,
		ubit_t *	output,
		int	n
	)

References _conv_encode_do_output(), osmo_conv_encoder::code, osmo_conv_encoder::i_idx, n, osmo_conv_code::next_output, osmo_conv_code::next_state, and osmo_conv_encoder::state.

Referenced by osmo_conv_encode().

osmo_conv_get_input_length()

int osmo_conv_get_input_length	(	const struct osmo_conv_code *	code,
		int	len
	)

References len(), and osmo_conv_code::len.

Referenced by osmo_conv_get_output_length().

osmo_conv_get_output_length()

int osmo_conv_get_output_length	(	const struct osmo_conv_code *	code,
		int	len
	)

References CONV_TERM_FLUSH, osmo_conv_code::K, len(), osmo_conv_code::N, osmo_conv_get_input_length(), osmo_conv_code::puncture, and osmo_conv_code::term.