[28] | 1 | // |
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| 2 | // Cognitive radio simulator |
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| 3 | // |
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| 4 | |
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| 5 | #include <stdio.h> |
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| 6 | #include <stdlib.h> |
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| 7 | #include <math.h> |
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| 8 | #include <sigprocc/sigprocc.h> |
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| 9 | #include "cognitive_radio_test.h" |
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| 10 | |
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| 11 | // options |
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| 12 | #define PACKET_SIZE 1024 // packet size (number of bits) |
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| 13 | #define NUM_TRIALS 250 // number of epochs |
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| 14 | #define REPORT_TRIALS 10 // print report every so often |
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| 15 | |
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| 16 | int main() { |
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| 17 | // bookkeeping variables and buffers |
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| 18 | unsigned int num_bits=PACKET_SIZE; |
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| 19 | char msg_in[num_bits], msg_out[num_bits]; |
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| 20 | float I[num_bits], Q[num_bits]; |
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| 21 | unsigned int num_symbols, num_bits_out; |
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| 22 | |
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| 23 | float noise_psd = -100.0f; // noise power spectral density |
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| 24 | float noise_power, noise_std; |
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| 25 | |
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| 26 | // quality of service metrics |
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| 27 | unsigned int num_bit_errors; |
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| 28 | float throughput_bps; |
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| 29 | |
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| 30 | // metadata defaults |
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| 31 | struct metadata_t mdt; |
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| 32 | metadata md = &mdt; |
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| 33 | |
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| 34 | md->mod_scheme = MOD_QAM; // MOD_PSK, MOD_QAM, MOD_PAM, MOD_DPSK |
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| 35 | md->mod_bps = 4; // modulation scheme [bits/s] |
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| 36 | md->tx_power_dBW = -3.0f; // transmit power [dBW] |
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| 37 | md->symbol_rate = 250e3f; // symbol rate [symbols/s] |
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| 38 | |
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| 39 | unsigned int i; |
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| 40 | // generate random message |
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| 41 | for (i=0; i<num_bits; i++) |
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| 42 | msg_in[i] = (char) (rand() % 2); |
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| 43 | |
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| 44 | printf("epoch\tutility\n"); |
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| 45 | printf("-----\t-------\n"); |
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| 46 | for (i=0; i<NUM_TRIALS; i++) { |
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| 47 | // compute internals |
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| 48 | noise_power = noise_psd + 20*log10f(md->symbol_rate); |
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| 49 | noise_std = powf(10.0f, (noise_power - md->tx_power_dBW) / 10.0f) / 2.0f; |
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| 50 | |
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| 51 | // execute transmitter |
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| 52 | execute_tx(md, msg_in, num_bits, I, Q, &num_symbols); |
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| 53 | |
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| 54 | // execute channel |
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| 55 | execute_channel(md, noise_std, I, Q, num_symbols); |
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| 56 | |
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| 57 | // execute receiver |
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| 58 | execute_rx(md, I, Q, num_symbols, msg_out, &num_bits_out); |
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| 59 | |
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| 60 | // |
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| 61 | // *** compute quality of service metrics *** |
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| 62 | // |
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| 63 | |
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| 64 | // count errors, etc. |
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| 65 | num_bit_errors = count_errors(msg_in, msg_out, num_bits); |
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| 66 | throughput_bps = ((float)(md->mod_bps)) * md->symbol_rate; |
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| 67 | |
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| 68 | if ( ((i+1)%REPORT_TRIALS)==0 || (i+1)==NUM_TRIALS) { |
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| 69 | // print results |
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| 70 | printf("%u\t%.2f\terrors:\t%u\t/ %u, power: %.1f dBW, Fs: %.3f kHz\n", |
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| 71 | i+1, 0.0f, num_bit_errors, num_bits, md->tx_power_dBW, md->symbol_rate/1e3 ); |
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| 72 | } |
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| 73 | |
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| 74 | // |
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| 75 | // *** execute cognition here *** |
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| 76 | // |
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| 77 | |
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| 78 | // simple power adaptation |
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| 79 | if (num_bit_errors > 30) { |
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| 80 | md->tx_power_dBW += 0.1f; |
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| 81 | } else { |
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| 82 | md->tx_power_dBW -= 0.1f; |
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| 83 | } |
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| 84 | |
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| 85 | } |
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| 86 | |
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| 87 | printf("done.\n"); |
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| 88 | return 0; |
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| 89 | } |
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