hamnet70/impl/src/main.c

#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <liquid/liquid.h>

#include "utils.h"
#include "packet_mod.h"
#include "config.h"
#include "preamble.h"

int main(void)
{
	uint8_t msg_org[] = "Hello Liquid! This is the message to transmit. Hopefully it can be decoded correctly...";

	fec q = fec_create(CHANNEL_CODE, NULL);

	modem demod = modem_create(MODULATION);

	channel_cccf channel = channel_cccf_create();

	float snr = 20.0f;
	channel_cccf_add_awgn(channel, -snr, snr);


	unsigned int k = fec_get_enc_msg_length(CHANNEL_CODE, sizeof(msg_org));

	packet_mod_ctx_t pmod;
	packet_mod_init(&pmod);

	packet_mod_set_data(&pmod, msg_org, sizeof(msg_org));
	packet_mod_encode(&pmod);
	packet_mod_modulate(&pmod);
	packet_mod_add_header(&pmod);
	packet_mod_add_preamble(&pmod);

	size_t nsyms;
	packet_mod_get_result_cf(&pmod, NULL, &nsyms); // determine number of symbols for allocation

	float complex msg_mod[nsyms];
	packet_mod_get_result_cf(&pmod, msg_mod, &nsyms); // get the data
	dump_array_cf(msg_mod, nsyms, 1.0f, "/tmp/tx.cpx");

	// channel
	float complex msg_received[nsyms];

	nsyms = nsyms - 63 - 16;

	//memcpy(msg_received, msg_mod, sizeof(msg_received)); // no noise in channel

	channel_cccf_execute_block(channel, msg_mod + 63 + 16, nsyms, msg_received);
	dump_array_cf(msg_received, nsyms, 1.0f, "/tmp/rx.cpx");

	// demodulate
	unsigned int bps = modem_get_bps(demod);

	unsigned char msg_demod_syms[nsyms];
	unsigned char msg_demod[k+1];

	for(size_t i = 0; i < nsyms; i++) {
		unsigned int symbol;

		modem_demodulate(demod, msg_received[i], &symbol);
		msg_demod_syms[i] = symbol;
	}

	unsigned int received_bytes;
	liquid_repack_bytes(msg_demod_syms, bps, nsyms, msg_demod, 8, sizeof(msg_demod), &received_bytes);

	//assert(received_bytes == k);

	// decode
	uint8_t msg_dec[sizeof(msg_org)];
	//memcpy(msg_dec, msg_enc, sizeof(msg_dec));
	fec_decode(q, sizeof(msg_dec), msg_demod, msg_dec);

	// compare original to decoded message
	for(size_t i = 0; i < sizeof(msg_org); i++)
	{
		printf("%02x  =>  %02x", msg_org[i], msg_dec[i]);
		if(msg_org[i] != msg_dec[i]) {
			printf("  <<< !!!\n");
		} else {
			printf("\n");
		}
	}

	unsigned int bit_errors = count_bit_errors_array(msg_org, msg_dec, sizeof(msg_org));
	printf("%u bit errors detected.\n", bit_errors);

	fec_destroy(q);

	modem_destroy(demod);

	channel_cccf_destroy(channel);

	printf("Done.\n");
}