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I was going through the workshop examples in the WARP repository.
I want to configure the different radio boards on the WARP receiver to tune into different carrier channels at the same time to implement a spectrum sensing algorithm.
In the Matlab code warplab_siso_example_continuousTx.m , udp node of the receiver board has been set to a specific channel and thus all the radio boards will only tune into that carrier channel simultaneously. How do I make necessary changes to implement a system wherein each radio board tunes into a different channel independently ?
Also, I would like to know how transmitter and receiver can be made to function concurrently using matlab. Right now in the above mentioned code, a packet is being transmitted and the receiver accepts it. I want the tx to transmit indefinitely and rx to receive and process the signal simultaneously in matlab.
Last edited by Rohan Surana (2009-Jun-04 06:50:39)
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WARPLab consists of two major components- the MATLAB code running on your PC, and the design running in the FPGA. The source project for the standard WARPLab FPGA design is available in the repository. The changes you mentioned will require updating the C code running in the FPGA's processor core using Xilinx Platform Studio (part of the Xilinx EDK). The XPS tutorial and workshop exercises 2-6 introduce this tool. None of these address modifying WARPLab specifically, but the design flow is identical.
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I am working on the warplab_example_TxRx_WorkshopExercise_Solution.m file (in Warplab_siso folder).
I have directly connected the transmitter to receiver using a cable and hence minimizing any external noise.
When I set the same carrier channel for Tx and Rx and computed the FFT of TxData and RxData. In some cases like CarrierChannel= 4 or 9 the FFT results are differing (which should not be the case). I dont understand how it is possible.
Also, when I set different carrier channels for Tx and Rx (so that the Rx doesnt receive any data) and again compute FFT on Txdata and RxData ,I get peaks for certain combinations of the carrierchannels. Please help.
I did the following changes in the existing code:
CarrierChannelTx=2;
CarrierChannelRx=8;
optionsVector = [CaptOffset TxLength-1 (RxGainBB + RxGainRF*2^16) (TxGainRF + TxGainBB*2^16) CarrierChannelTx];
optionsVector1 = [CaptOffset TxLength-1 (RxGainBB + RxGainRF*2^16) (TxGainRF + TxGainBB*2^16) CarrierChannelRx];
warplab_setOptions(socketHandles(1:2),optionsVector);
warplab_setOptions(socketHandles(3),optionsVector1);
Last edited by Rohan Surana (2009-Jun-05 08:28:03)
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Rohan Surana wrote:
I have directly connected the transmitter to receiver using a cable and hence minimizing any external noise.
As mentioned elsewhere on these forums, you need to have at least 30dB attenuation between Tx and Rx. If you use a cable in place of antennas, you need at least a 30dB attenuator in series.
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I have also tried the experiment on bit error rate calculation. If I set the Tx channel to 11 , then no matter what my Rx channel is, I am able to receive the data with 0 BER. Also another problem is Tx-channel-5 with Rx-channel-11 works better than Tx-channel-5 with Rx-channel-5. This time I used antennas. I think while I was editing the previous post, you replied to it. Please have a look at it again. I am really confused. Need help.
Last edited by Rohan Surana (2009-Jun-05 08:41:14)
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A few things:
-You should be using the latest version of the WARPLab reference design (currently v04), as described on the WARPLab page. All of the files are in the repository (WARPLab_MIMO2x2_MIMO4x4_R04). The code in warplab_siso is much older.
-The first socket handle shouldn't be used for anything but sending the broadcast SYNC packet (i.e. it shouldn't be the target of options, data, etc.).
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