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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