Changes between Version 86 and Version 87 of Other/Summer/2015/aSDR2


Ignore:
Timestamp:
Jul 15, 2015, 6:44:29 PM (9 years ago)
Author:
mlcoll
Comment:

—

Legend:

Unmodified
Added
Removed
Modified

  • Other/Summer/2015/aSDR2

    v86 v87  
    110110=== Experiments ===
    111111
     112==== Experiment 1: Signal Transmission and Processing with USRP2 and wiserd [=#Exp1]
     113
     114In this experiment we modify the [[http://www.orbit-lab.org/wiki/Tutorials/k0SDR/Tutorial05#SpectrumsensingwithUSRP2andwiserdOEDLandOML|Spectrum sensing with USRP2 and wiserd (OEDL and OML)]] tutorial.
     115[[BR]][[BR]]
     116The tutorial uses two USRPs: one transmitter and one receiver. The transmitter starts at 798 MHz and increases to 802 MHz over a span of 5 seconds. The receiver has a carrier frequency of 800 MHz and bandwidth of 5 MHz.
     117[[BR]][[BR]]
     118As our first experiment we modified the tutorial. We increase the sampling rate to 10 MHz, so we can accurately receive frequencies up to 5 MHz greater or lesser than the receiver's carrier frequency. We then randomly select frequencies from 796 to 804 MHz to transmit for one second each.
     119[[BR]][[BR]]
     120Using OML, we save the receiver readings to a file for processing in MATLAB/Octave. Using a MATLAB script, we generate a waterfall plot of the data, along with an animated power vs. frequency plot. See //Figure 1.//
     121
    112122{{{#!html
    113123
    114 <table align=right cellpadding=10 width=50%>
     124<table align=center cellpadding=10 width=70%>
    115125  <tr>
    116126    <td><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR2/exp1_1.png" width=100%>
    … …  
    125135}}}
    126136
     137'''Update: Raw IQ Samples and Processing in MATLAB'''
    127138
    128 ==== Experiment 1: Signal Transmission and Processing with USRP2 and wiserd [=#Exp1]
    129 
    130 In this experiment we modify the [[http://www.orbit-lab.org/wiki/Tutorials/k0SDR/Tutorial05#SpectrumsensingwithUSRP2andwiserdOEDLandOML|Spectrum sensing with USRP2 and wiserd (OEDL and OML)]] tutorial.
     139Next, using the same frequencies and sampling rate as the original tutorial, we modified the OEDL script in order to collect raw time domain samples using ORBIT as opposed to samples that had already been converted into the frequency domain.
    131140[[BR]][[BR]]
    132 The tutorial uses two USRPs: one transmitter and one receiver. The transmitter starts at 798 MHz and increases to 802 MHz over a span of 5 seconds. The receiver has a carrier frequency of 800 MHz and bandwidth of 5 MHz.
     141We then wrote a MATLAB script entitled "spectro" which we used to convert the raw data into the frequency domain. From there, we again generate a waterfall plot of the data. See //Figure 2.//
    133142[[BR]][[BR]]
    134 As our first experiment we modified the tutorial. We increase the sampling rate to 10 MHz, so we can accurately receive frequencies up to 5 MHz greater or lesser than the receiver's carrier frequency. We then randomly select frequencies from 796 to 804 MHz to transmit for one second each.
    135 [[BR]][[BR]]
    136 Using OML, we save the receiver readings to a file for processing in MATLAB/Octave. Using a MATLAB script, we generate a waterfall plot of the data, along with an animated power vs. frequency plot.
    137 [[BR]][[BR]]
    138 
     143Using the raw IQ samples instead of preprocessed FFT data allows for more flexibility in our signal processing. We now have access to a much larger collection of data, and we can produce more accurate frequency domain transforms.
    139144
    140145{{{#!html
    141146
    142 <table align=left cellpadding=10 width=20%>
     147<table align=center cellpadding=10 width=40%>
    143148  <tr>
    144149    <td><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR2/exp1_3.png" align=middle width=100%></td>
    … …  
    150155}}}
    151156
     157----------
     158==== Experiment 2: Signal Transmission and Processing with Two Transmitters and One Receiver [=#Exp2]
    152159
    153 '''Update: Raw IQ Samples and Processing in MATLAB'''
     160In this experiment, we write an OEDL script that uses two transmitters and one receiver to collect preprocessed FFT samples. Utilizing three USRP2 radios on the grid, two nodes were used as transmitters, and one as a receiver.
     161[[BR]][[BR]]
     162The first transmitter starts at a frequency of 798 MHz and increases to 802 MHz, while the second transmitter starts at a frequency of 804 Mhz and increases to 808 MHz all over a span of 2.5 seconds. The receiver has a carrier frequency of 803 MHz and a bandwidth of 12 Mhz.
     163[[BR]][[BR]]
     164We then save the FFT data from the receiver to our local device and process in MATLAB, where we generated a waterfall plot of the data. See //Figure 3.//
    154165
    155 Next, using the same frequencies and sampling rate as the original tutorial, we modified the OEDL script in order to collect raw time domain samples using ORBIT as opposed to samples that had already been converted into the frequency domain.
    156 [[BR]][[BR]]
    157 We then wrote a MATLAB script entitled "spectro" which we used to convert the raw data into the frequency domain. From there, we again generate a waterfall plot of the data.
    158 [[BR]][[BR]]
    159 Using the raw IQ samples instead of preprocessed FFT data allows for more flexibility in our signal processing. We now have access to a much larger collection of data, and we can produce more accurate frequency domain transforms.
    160 
    161 
    162 ----------
    163166{{{#!html
    164167
    165 <table align=right cellpadding=10 width=35%>
     168<table align=center cellpadding=10 width=50%>
    166169  <tr>
    167170    <td><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR2/grid_exp1.png" width=100%></td>
    … …  
    175178}}}
    176179
    177 ==== Experiment 2: Signal Transmission and Processing with Two Transmitters and One Receiver [=#Exp2]
    178 
    179 In this experiment, we write an OEDL script that uses two transmitters and one receiver to collect preprocessed FFT samples. Utilizing three USRP2 radios on the grid, two nodes were used as transmitters, and one as a receiver.
    180 [[BR]][[BR]]
    181 The first transmitter starts at a frequency of 798 MHz and increases to 802 MHz, while the second transmitter starts at a frequency of 804 Mhz and increases to 808 MHz all over a span of 2.5 seconds. The receiver has a carrier frequency of 803 MHz and a bandwidth of 12 Mhz.
    182 [[BR]][[BR]]
    183 We then save the FFT data from the receiver to our local device and process in MATLAB, where we generated a waterfall plot of the data.
    184 
    185 
     180Once we have the experiment set up, we can extract IQ samples from the receiver and use them in our MATLAB processing script.
     181[[BR]]
     182The script currently generates a waterfall plot, plots individual FFTs and applies a simple peak-finding algorithm to identify possible transmitted frequencies. See //Figure 4.//