test_256qam_demod.cc File Reference

#include <gtest/gtest.h>
#include <random>
#include "gettime.h"
#include "memory_manage.h"
#include "message.h"
#include "modulation.h"

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Macros
#define	NUM_SYMBOLS   1000
#define	NUM_ITERATIONS   50

Functions
static void	ApplyAwgn (complex_float *signal, complex_float *output, int len, float snr)
static void	Run256QamSoftDemod (void(*demod_func)(const float *, int8_t *, int), const char *func_desc)
	TEST (TestDemod256QAM, SoftLoop)
	TEST (TestDemod256QAM, SoftSSE)
	TEST (TestDemod256QAM, SoftAVX2)
	TEST (TestDemod256QAM, VerifyCorrectness)
int	main (int argc, char **argv)

Macro Definition Documentation

NUM_ITERATIONS

#define NUM_ITERATIONS   50

NUM_SYMBOLS

#define NUM_SYMBOLS   1000

Function Documentation

ApplyAwgn()

static void ApplyAwgn ( complex_float *  signal, complex_float *  output, int  len, float  snr  )

static

Adds additive white gaussian noise to the supplied signal

Parameters

signal	input signal
output	output signal
len	length of input and output signal (number of symbols)
snr	desired SNR in dB

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main()

int main	(	int	argc,
		char **	argv
	)

Run256QamSoftDemod()

static void Run256QamSoftDemod ( void(*)(const float *, int8_t *, int)  demod_func, const char *  func_desc  )

static

Runs 256 QAM soft demodulation across several SNR values, using the provided function for demodulation. Provided to simplify testing.

Parameters

demod_func	Function to use for demodulation
func_desc	string describing function

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TEST() [1/4]

TEST	(	TestDemod256QAM	,
		SoftAVX2
	)

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TEST() [2/4]

TEST	(	TestDemod256QAM	,
		SoftLoop
	)

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TEST() [3/4]

TEST	(	TestDemod256QAM	,
		SoftSSE
	)

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TEST() [4/4]

TEST	(	TestDemod256QAM	,
		VerifyCorrectness
	)

Unlike the rest of the testing suite, this test verifies that all AVX implementations of 256 QAM demodulation produce the EXACT same LLR results. It treats the SSE implementation as a ground truth.

Note: the SSE implementation was verified against the loop one during testing. The loop implementation rounds floats differently, resulting in a slightly different LLR. This is why the SSE implementation is used as a ground truth.

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