[1671] | 1 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 2 | % Spectrum sensing using WARPLab |
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| 3 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 4 | |
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| 5 | % The specific steps implemented in this script are the following: |
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| 6 | |
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| 7 | % 0. Initialization and definition of parameters |
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| 8 | % 1. Prepare the WARP node for reception (sensing the medium) and send trigger to |
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| 9 | % start reception (trigger is the SYNC packet) |
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| 10 | % 2. Read the received samples from the WARP node |
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| 11 | % 3. Reset and disable the WARP node |
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| 12 | % 4. Compute and plot the fft of the received data |
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| 13 | % 5. Plot the received waveform |
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| 14 | % 6. Compute the Received Signal Strength Indicator (RSSI in dBm) of the received signal |
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| 15 | % 7. Close sockets |
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| 16 | |
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| 17 | % In this lab exercise you will write a matlab script that implements the |
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| 18 | % steps above. Part of the code is provided, some part of the code you |
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| 19 | % will write. Read the code below and fill in with your code wherever you |
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| 20 | % are asked to do so. |
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| 21 | |
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| 22 | % WARPLab documentation can be found online at |
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| 23 | % http://warp.rice.edu/trac/wiki/WARPLab |
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| 24 | |
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| 25 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 26 | |
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| 27 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 28 | % 0. Initializaton and definition of parameters |
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| 29 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 30 | |
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| 31 | %Load some global definitions (packet types, etc.) |
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| 32 | warplab_defines |
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| 33 | |
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| 34 | % Create Socket handles and intialize nodes |
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| 35 | [socketHandles, packetNum] = warplab_initialize(1); |
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| 36 | |
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| 37 | % Separate the socket handles for easier access |
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| 38 | % The first socket handle is always the magic SYNC |
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| 39 | % The rest of the handles are the handles to the WARP nodes |
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| 40 | udp_Sync = socketHandles(1); % SYNC |
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| 41 | udp_node1 = socketHandles(2); % Handle for node 1: Receiver node |
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| 42 | |
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| 43 | % Define WARPLab parameters for this workshop exercise. |
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| 44 | |
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| 45 | %-------------------------------------------------------------------------% |
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| 46 | % USER CODE HERE |
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| 47 | |
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| 48 | % - Create a variable named 'Node1_SensingChannel' and assign a value to |
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| 49 | % this variable . |
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| 50 | % - Variable 'Node1_SensingChannel' can be any integer value in [1:14] range. |
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| 51 | % - The value of Node1_SensingChannel specifies a channel in the 2.4 GHz band |
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| 52 | % and this is the channel at which sensing wll be centered |
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| 53 | |
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| 54 | Node1_SensingChannel = 1; |
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| 55 | %-------------------------------------------------------------------------% |
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| 56 | |
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| 57 | %-------------------------------------------------------------------------% |
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| 58 | % USER CODE HERE |
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| 59 | |
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| 60 | % - Set the sensing channel of node 1 by using the 'warplab_setRadioParameter' |
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| 61 | % function and the 'Node1_SensingChannel' variable just defined |
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| 62 | |
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| 63 | % The 'warplab_setRadioParameter' function has three arguments which are specified below: |
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| 64 | %(The arguments in the 'warplab_setRadioParameter' function do not use the quotes '') |
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| 65 | |
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| 66 | % 1. The first argument of the 'warplab_setRadioParameter' function identifies the |
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| 67 | % node where the radio parameter will be set. The id or handle to node 1 is |
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| 68 | % 'udp_node1'. |
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| 69 | |
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| 70 | % 2. The second argument of the 'warplab_setRadioParameter' function identifies the |
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| 71 | % radio parameter that will be set. The sensing channel is the receiver center |
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| 72 | % frequency or carrier channel. To set the sensing channel, the radio |
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| 73 | % parameter that needs to be set is the parameter identified as |
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| 74 | % 'CARRIER_CHANNEL'. |
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| 75 | |
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| 76 | % 3. The third argument of the 'warplab_setRadioParameter' function is the channel |
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| 77 | % number to be set. Use as third argument the variable 'Node1_SensingChannel' |
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| 78 | % that you have previously defined |
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| 79 | |
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| 80 | warplab_setRadioParameter(udp_node1,CARRIER_CHANNEL,Node1_SensingChannel); |
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| 81 | %-------------------------------------------------------------------------% |
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| 82 | |
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| 83 | %-------------------------------------------------------------------------% |
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| 84 | % USER CODE HERE |
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| 85 | |
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| 86 | % - Create a variable named 'Node1_Radio2_RxGain_BB' and assign a value to |
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| 87 | % this variable . |
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| 88 | % - Node1_Radio2_RxGain_BB can be any integer value in [0:31] range. |
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| 89 | % - Node1_Radio2_RxGain_BB is the baseband gain applied by the receiver. |
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| 90 | % - Each unit step increase in the value of Node1_Radio2_RxGain_BB |
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| 91 | % corresponds to a 2 dB increase of gain applied to the received signal. |
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| 92 | |
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| 93 | Node1_Radio2_RxGain_BB = 13; |
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| 94 | %-------------------------------------------------------------------------% |
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| 95 | |
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| 96 | |
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| 97 | %-------------------------------------------------------------------------% |
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| 98 | % USER CODE HERE |
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| 99 | |
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| 100 | % - Create a variable named 'Node1_Radio2_RxGain_RF' and assign a value to |
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| 101 | % this variable . |
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| 102 | % - Node1_Radio2_RxGain_RF can be any integer value in [1:3] range. |
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| 103 | % - Node1_Radio2_RxGain_RF is the RF gain applied by the receiver. |
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| 104 | % - Each unit step increase in the value of Node1_Radio2_RxGain_RF |
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| 105 | % corresponds to a 15 dB increase of gain applied to the received signal. |
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| 106 | |
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| 107 | Node1_Radio2_RxGain_RF = 3; |
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| 108 | %-------------------------------------------------------------------------% |
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| 109 | |
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| 110 | % Set the baseband and RF receiver gains of the radio by using the 'warplab_setRadioParameter' |
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| 111 | % function and the 'Node1_Radio2_RxGain_BB' and 'Node1_Radio2_RxGain_RF' variables just defined |
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| 112 | warplab_setRadioParameter(udp_node1,RADIO2_RXGAINS,(Node1_Radio2_RxGain_BB + Node1_Radio2_RxGain_RF*2^16)); |
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| 113 | |
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| 114 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 115 | % 1. Prepare the WARP node for reception (sensing the medium) and send trigger to |
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| 116 | % start reception (trigger is the SYNC packet) |
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| 117 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 118 | |
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| 119 | %-------------------------------------------------------------------------% |
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| 120 | % USER CODE HERE |
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| 121 | |
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| 122 | % Enable radio 2 in node 1 as receiver by sending the 'RADIO2_RXEN' command |
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| 123 | % to node 1 using the 'warplab_sendCmd' function. |
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| 124 | |
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| 125 | % The 'warplab_sendCmd' function has three arguments which are specified below: |
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| 126 | %(The arguments in the 'warplab_setRadioParameter' function do not use the quotes '') |
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| 127 | |
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| 128 | % 1. The first argument of the 'warplab_sendCmd' function identifies the |
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| 129 | % node to which the command will be sent to. The id or handle to node 1 is |
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| 130 | % 'udp_node1'. |
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| 131 | |
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| 132 | % 2. The second argument of the 'warplab_sendCmd' function identifies the |
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| 133 | % command that will be sent. |
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| 134 | |
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| 135 | % 3. The third argument of the 'warplab_sendCmd' command is a field that is |
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| 136 | % not used at the moment, it may be used in future versions of WARPLab to |
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| 137 | % keep track of packets. Use 'packetNum' as the third argument of the |
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| 138 | % 'warplab_sendCmd' function. |
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| 139 | |
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| 140 | warplab_sendCmd(udp_node1, RADIO2_RXEN, packetNum); |
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| 141 | %-------------------------------------------------------------------------% |
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| 142 | |
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| 143 | %-------------------------------------------------------------------------% |
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| 144 | % USER CODE HERE |
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| 145 | |
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| 146 | % Enable storage of samples in the receive buffer that is connected to |
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| 147 | % radio 2 in node 1 by sending the RADIO2RXBUFF_RXEN command to |
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| 148 | % node 1 using the 'warplab_sendCmd' function. |
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| 149 | |
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| 150 | % The 'warplab_sendCmd' function has been described above |
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| 151 | |
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| 152 | warplab_sendCmd(udp_node1, RADIO2RXBUFF_RXEN, packetNum); |
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| 153 | %-------------------------------------------------------------------------% |
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| 154 | |
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| 155 | % Prime receiver state machine in node 1. Node 1 will be waiting |
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| 156 | % for the SYNC packet. Capture at node 1 will be triggered when node 1 |
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| 157 | % receives the SYNC packet. |
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| 158 | warplab_sendCmd(udp_node1, RX_START, packetNum); |
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| 159 | |
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| 160 | % Send the SYNC packet |
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| 161 | warplab_sendSync(udp_Sync); |
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| 162 | |
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| 163 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 164 | % 2. Read the received samples from the WARP node |
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| 165 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 166 | BufferSize = 2^14; |
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| 167 | |
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| 168 | %-------------------------------------------------------------------------% |
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| 169 | % USER CODE HERE |
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| 170 | |
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| 171 | % Read the received samples from the WARP node using the |
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| 172 | % 'warplab_readSMRO' function. Store the samples output by the warplab_readSMRO |
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| 173 | % function samples in a variable named 'Node1_Radio2_RawRxData'. |
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| 174 | |
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| 175 | % The arguments of the 'warplab_readSMRO' function are the following: |
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| 176 | %(The arguments in the 'warplab_setRadioParameter' function do not use the quotes '') |
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| 177 | |
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| 178 | % 1. The first argument of the 'warplab_readSMRO' function identifies the |
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| 179 | % node from which samples will be read. In this exercise there is only one |
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| 180 | % node and the id or handle to node 1 is 'udp_node1'. |
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| 181 | |
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| 182 | % 2. The second argument of the 'warplab_readSMRO' function identifies the |
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| 183 | % receive buffer from which samples will be read. For this exercise samples |
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| 184 | % were captured in node 1 radio 2, hence, samples must be read from radio 2 |
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| 185 | % Rx buffer, the id for this buffer is 'RADIO2_RXDATA'. |
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| 186 | |
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| 187 | % 3. The third argument of the 'warplab_readSMRO' function is the number of |
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| 188 | % samples to read; reading of samples always starts from address zero in |
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| 189 | % the receive buffer. For this exercise set the third argument of the 'warplab_readSMRO' |
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| 190 | % function equal to 'BufferSize' which has been defined in the code to be |
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| 191 | % equal to 2^14 which is the maximum number of samples that can be stored |
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| 192 | % in the receive buffer, hence you will read the entire receive buffer |
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| 193 | |
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| 194 | [Node1_Radio2_RawRxData] = warplab_readSMRO(udp_node1, RADIO2_RXDATA, BufferSize); |
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| 195 | %-------------------------------------------------------------------------% |
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| 196 | |
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| 197 | % Process the received samples to obtain meaningful data |
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| 198 | [Node1_Radio2_RxData,Node1_Radio2_RxOTR] = warplab_processRawRxData(Node1_Radio2_RawRxData); |
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| 199 | |
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| 200 | % Read stored RSSI data |
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| 201 | [Node1_Radio2_RawRSSIData] = warplab_readSMRO(udp_node1, RADIO2_RSSIDATA, ceil(BufferSize/8)); |
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| 202 | |
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| 203 | % Process Raw RSSI data to obtain meningful RSSI values |
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| 204 | [Node1_Radio2_RSSIData] = warplab_processRawRSSIData(Node1_Radio2_RawRSSIData); |
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| 205 | |
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| 206 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 207 | % 3. Reset and disable the WARP node |
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| 208 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 209 | %-------------------------------------------------------------------------% |
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| 210 | % USER CODE HERE |
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| 211 | |
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| 212 | % Set radio 2 in node 1 back to Rx disabled mode by sending the |
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| 213 | % 'RADIO2_RXDIS' command to node 1 using the 'warplab_sendCmd' function. |
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| 214 | |
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| 215 | % The 'warplab_sendCmd' function has been described above |
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| 216 | |
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| 217 | warplab_sendCmd(udp_node1, RADIO2_RXDIS, packetNum); |
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| 218 | %-------------------------------------------------------------------------% |
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| 219 | |
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| 220 | %-------------------------------------------------------------------------% |
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| 221 | % USER CODE HERE |
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| 222 | |
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| 223 | % Set storage of samples in the receive buffer that is connected to |
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| 224 | % radio 2 in node 1 back to disabled mode by sending the RADIO2RXBUFF_RXDIS |
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| 225 | % command to node 1 using the 'warplab_sendCmd' function. |
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| 226 | |
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| 227 | warplab_sendCmd(udp_node1, RADIO2RXBUFF_RXDIS, packetNum); |
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| 228 | %-------------------------------------------------------------------------% |
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| 229 | |
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| 230 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 231 | % 4. Compute and plot the fft of the received data |
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| 232 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 233 | % Computation of fft is based on the example in MATLAB's fft |
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| 234 | % documentation, see help fft for more information on MATLAB's fft function |
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| 235 | |
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| 236 | % Compute and plot the fft of the received signal |
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| 237 | % Compute fft |
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| 238 | L=length(Node1_Radio2_RxData); % Get length of transmitted vector |
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| 239 | NFFT = 2^nextpow2(L); % Next power of 2 from length of y |
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| 240 | Y = fftshift(fft(Node1_Radio2_RxData,NFFT)/L); % Compute fft |
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| 241 | Fs=40e6; % Sampling frequency is equal to 40e6 |
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| 242 | f = Fs/2*linspace(0-1,1,NFFT); |
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| 243 | |
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| 244 | % Plot fft |
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| 245 | figure |
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| 246 | plot(f/10^6,abs(Y)) |
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| 247 | title('Spectrum of received signal in current carrier channel') |
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| 248 | xlabel('Frequency (MHz)') |
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| 249 | ylabel('Magnitude') |
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| 250 | xlim([-10 10]) |
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| 251 | |
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| 252 | |
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| 253 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 254 | % Attendees code: |
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| 255 | % 5. Plot the received waveform |
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| 256 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 257 | figure |
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| 258 | subplot(2,2,1); |
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| 259 | plot(real(Node1_Radio2_RxData)); |
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| 260 | title('Rx Node 2 Radio 2 I'); |
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| 261 | xlabel('n (samples)'); ylabel('Amplitude'); |
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| 262 | axis([0 2^14 -1 1]); % Set axis ranges. |
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| 263 | subplot(2,2,2); |
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| 264 | plot(imag(Node1_Radio2_RxData)); |
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| 265 | title('Rx Node 2 Radio 2 Q'); |
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| 266 | xlabel('n (samples)'); ylabel('Amplitude'); |
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| 267 | axis([0 2^14 -1 1]); % Set axis ranges. |
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| 268 | |
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| 269 | % Plot amplitude versus time |
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| 270 | subplot(2,2,3); |
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| 271 | plot([0:1:length(Node1_Radio2_RxData)-1]/40e6,real(Node1_Radio2_RxData)); |
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| 272 | title('Rx Node 2 Radio 2 I'); |
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| 273 | xlabel('time (s)'); ylabel('Amplitude'); |
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| 274 | axis([0 (length(Node1_Radio2_RxData)-1)/40e6 -1 1]); % Set axis ranges. |
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| 275 | subplot(2,2,4); |
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| 276 | plot([0:1:length(Node1_Radio2_RxData)-1]/40e6,imag(Node1_Radio2_RxData)); |
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| 277 | title('Rx Node 2 Radio 2 Q'); |
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| 278 | xlabel('time (s)'); ylabel('Amplitude'); |
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| 279 | axis([0 (length(Node1_Radio2_RxData)-1)/40e6 -1 1]); % Set axis ranges. |
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| 280 | |
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| 281 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 282 | % 6. Compute the Received Signal Strength Indicator (RSSI in dBm) of the received signal |
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| 283 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 284 | % RSSI measurements were stored in 'Node1_Radio2_RSSIData' variable. |
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| 285 | % Average over all measurements of RSSI |
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| 286 | RSSI_Avg = mean(Node1_Radio2_RSSIData); |
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| 287 | |
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| 288 | % Convert RSSIAvg to dBm. |
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| 289 | % The conversion is based on the following radio and RSSI vaue specifications: |
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| 290 | % For high receiver gain (Node1_Radio2_RxGain_RF = 3), RSSI_Avg=0 is -100dBm; RSSI_Avg=1023 is -30dBm. |
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| 291 | % For medium receiver gain (Node1_Radio2_RxGain_RF = 2), RSSI_Avg=0 is -85dBm; RSSI_Avg=1023 is -15dBm. |
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| 292 | % For low receiver gain (Node1_Radio2_RxGain_RF = 1), RSSI_Avg=0 is -70dBm; RSSI_Avg=1023 is 0dBm. |
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| 293 | |
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| 294 | RSSI_dBm = (70/1023)*RSSI_Avg - 70 - (Node1_Radio2_RxGain_RF-1)*15; |
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| 295 | fprintf('\nRSSI dBm = %5.2f\n',RSSI_dBm) |
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| 296 | |
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| 297 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 298 | % 7. Close sockets |
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| 299 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 300 | pnet('closeall'); |
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