DKAB bursts

Files
file	dkab.h
	Osmocom GMR-1 DKABs bursts header.
file	dkab.c
	Osmocom GMR-1 DKABs bursts implementation.

Macros
#define	GMR1_DKAB_SYMS   (39*3)
#define	DKAB_PWR_RATIO_THRESHOLD   10.0f
	Ratio between peak power and valley power for DKAB detection.

Functions
int	gmr1_dkab_demod (struct osmo_cxvec *burst_in, int sps, float freq_shift, int p, sbit_t *ebits, float *toa_p)
	All-in-one finding and demodulation of DKAB bursts. More...

Detailed Description

Function Documentation

gmr1_dkab_demod()

int gmr1_dkab_demod	(	struct osmo_cxvec *	burst_in,
		int	sps,
		float	freq_shift,
		int	p,
		sbit_t *	ebits,
		float *	toa_p
	)

All-in-one finding and demodulation of DKAB bursts.

Parameters

[in]	burst_in	Complex signal of the burst
[in]	sps	Oversampling used in the input complex signal
[in]	freq_shift	Frequency shift to pre-apply to burst_in (rad/sym)
[in]	p	DKAB position
[out]	ebits	Encoded soft bits return array
[out]	toa_p	Pointer to TOA return variable

Returns

0 for success, 1 if DKAB not found, -errno for fatal errors

burst_in is expected to be longer than necessary. Any extra length will be used as 'search window' to find proper alignement. Good practice is to have a few samples too much in front and a few samples after the expected TOA.

References M_PIf, and osmo_cxvec_sig_normalize().