Changes between Version 4 and Version 5 of WARPLab/Examples/MIMO_OFDM


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Timestamp:
Aug 25, 2015, 4:08:11 PM (9 years ago)
Author:
chunter
Comment:

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  • WARPLab/Examples/MIMO_OFDM

    v4 v5  
    1313From there, the rest of the legacy preamble is identical to that seen in the [wiki:WARPLab/Examples/OFDM SISO OFDM example]. These Long Training Symbols (LTS) are used by the receiver to estimate and correct for Carrier Frequency Offset (CFO) as well as timing alignment via a cross correlator.
    1414
     15Finally, the preamble is concluded with time-orthogonalized transmission of channel training symbols from each of the two transmit antennas. These two symbols are used by the receiver to generate the 2x2 channel matrix for each of the data-bearing subcarriers of the OFDM waveform.
     16
    1517
    1618== Running the Example ==
    … …  
    2426||||||=  [[BR]]  =||
    2527
    26 By default the simulation script applies AWGN with an arbitrary fixed SNR. You can change the simulated propagation characteristics in the m-code. Search for {{{AWGN}}} and apply whatever Tx->Rx degradations you like.
    27 
    28 For example to simulate a perfect (noiseless) link, set the noise power to zero:
    29 {{{
    30 rx_vec_air = tx_vec_air + 0*complex(randn(1,length(tx_vec_air)), randn(1,length(tx_vec_air)));
    31 }}}
    32 
    33 The script also prints statistics about the experiment to the MATLAB command prompt:
    34 {{{
    35 Results:
    36 Num Bytes:  4560
    37 Sym Errors:  0 (of 9120 total symbols)
    38 Bit Errors:  0 (of 36480 total bits)
    39 EVM:        3.779%
    40 LTS CFO Est: -0.07 kHz
    41 }}}
     28By default the simulation script applies a deterministic combination of each spatial stream to each receive interface. This combination is frequency-flat and no noise is added. You can see the effect of this MIMO combining in the above figure with the "Unequalized Rx Symbols" plots.
    4229
    4330=== Hardware in the Loop ===
    4431
    45 '''Requirements: 2 WARP v3 kits, 1 antenna each.'''
     32'''Requirements: 2 WARP v3 kits, 2 antennas each.'''
    4633
    47 To use the example with WARP hardware you will need two WARP nodes each running WARPLab 7.3 (or later) and a WARPLab environment setup on your PC. Refer to the [wiki:../../QuickStart WARPLab Quick Start] if you have not yet setup WARPLab.
     34To use the example with WARP hardware you will need two WARP nodes each running WARPLab 7.5.1 (or later) and a WARPLab environment setup on your PC. Refer to the [wiki:../../QuickStart WARPLab Quick Start] if you have not yet setup WARPLab.
    4835
    4936To target WARP hardware set the top-level param {{{USE_WARPLAB_TXRX = 1;}}}, then run the m-script. When the script finishes 6 plots will show: