135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#include <liquid/liquid.h>
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#include "utils.h"
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#include "packet_mod.h"
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#include "config.h"
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#include "preamble.h"
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#include "transmission.h"
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int main(void)
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{
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uint8_t msg_org[] = "Hello Liquid! This is the message to transmit. Hopefully it can be decoded correctly...";
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fec q = fec_create(CHANNEL_CODE, NULL);
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modem demod = modem_create(MODULATION);
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channel_cccf channel = channel_cccf_create();
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float snr = 20.0f;
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channel_cccf_add_awgn(channel, -snr, snr);
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channel_cccf_add_carrier_offset(channel, 0.01f, 1.00f);
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packet_mod_ctx_t pmod;
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packet_mod_init(&pmod);
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packet_mod_set_data(&pmod, msg_org, sizeof(msg_org));
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packet_mod_encode(&pmod);
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packet_mod_modulate(&pmod);
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packet_mod_add_header(&pmod);
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packet_mod_add_preamble(&pmod);
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size_t nsyms;
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packet_mod_get_result_cf(&pmod, NULL, &nsyms); // determine number of symbols for allocation
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float complex msg_mod[nsyms];
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packet_mod_get_result_cf(&pmod, msg_mod, &nsyms); // get the data
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size_t burst_len = 0;
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float complex whole_burst[65536];
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size_t len;
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transmission_ctx_t transm;
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transmission_init(&transm);
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len = 65536-burst_len;
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if(transmission_ramp_up(&transm, whole_burst+burst_len, &len) != OK) {
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printf("Ramp-up requires %zd symbols at offset %zd.\n", len, burst_len);
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return 1;
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}
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burst_len += len;
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len = 65536-burst_len;
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if(transmission_filter_packet(&transm, msg_mod, nsyms, whole_burst+burst_len, &len) != OK) {
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printf("Packet requires %zd symbols at offset %zd.\n", len, burst_len);
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return 1;
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}
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burst_len += len;
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len = 65536-burst_len;
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if(transmission_ramp_down(&transm, whole_burst+burst_len, &len) != OK) {
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printf("Ramp-down requires %zd symbols at offset %zd.\n", len, burst_len);
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return 1;
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}
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burst_len += len;
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dump_array_cf(whole_burst, burst_len, 1.0f, "/tmp/tx.cpx");
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// channel
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float complex msg_received[burst_len];
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//memcpy(msg_received, whole_burst, sizeof(whole_burst)); // no noise in channel
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channel_cccf_execute_block(channel, whole_burst, burst_len, msg_received);
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dump_array_cf(msg_received, burst_len, 1.0f, "/tmp/rx.cpx");
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// create symbol synchronizer
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symsync_crcf symsync = symsync_crcf_create_rnyquist(LIQUID_FIRFILT_RRC, RRC_SPS, RRC_DELAY, RRC_BETA, 32);
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float complex symsync_out[burst_len];
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unsigned int symsync_out_len;
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symsync_crcf_execute(symsync, msg_received, burst_len, symsync_out, &symsync_out_len);
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dump_array_cf(symsync_out, symsync_out_len, 1.0f, "/tmp/rx.cpx");
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#if 0
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// demodulate
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unsigned int bps = modem_get_bps(demod);
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unsigned char msg_demod_syms[nsyms];
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unsigned char msg_demod[k+1];
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for(size_t i = 0; i < nsyms; i++) {
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unsigned int symbol;
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modem_demodulate(demod, msg_received[i], &symbol);
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msg_demod_syms[i] = symbol;
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}
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unsigned int received_bytes;
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liquid_repack_bytes(msg_demod_syms, bps, nsyms, msg_demod, 8, sizeof(msg_demod), &received_bytes);
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//assert(received_bytes == k);
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// decode
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uint8_t msg_dec[sizeof(msg_org)];
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//memcpy(msg_dec, msg_enc, sizeof(msg_dec));
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fec_decode(q, sizeof(msg_dec), msg_demod, msg_dec);
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// compare original to decoded message
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for(size_t i = 0; i < sizeof(msg_org); i++)
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{
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printf("%02x => %02x", msg_org[i], msg_dec[i]);
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if(msg_org[i] != msg_dec[i]) {
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printf(" <<< !!!\n");
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} else {
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printf("\n");
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}
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}
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unsigned int bit_errors = count_bit_errors_array(msg_org, msg_dec, sizeof(msg_org));
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printf("%u bit errors detected.\n", bit_errors);
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#endif
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fec_destroy(q);
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modem_destroy(demod);
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channel_cccf_destroy(channel);
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printf("Done.\n");
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}
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