Spectrum sensing with USRP2 and wiserd (OEDL and OML)

Description

We'll use the nodes on sandbox 3 to transmit a predefined waveform and receive the spectrum data into an OML file.

Hardware / Software Resources utilized

1. Grid nodes with a USRP2 connect via Ethernet.
2. baseline-sdr.ndz: disk image loaded onto nodes.
3. ​Wiserd - interface to configure and stream data to/from USRPs.

Transmit predefined tone

To get started load baseline-sdr.ndz onto node1-1 and node1-2. Then turn both nodes on.

Set up node1-1 to configure transmit a predefined sine wave

node1-1> wiserd
> --uhd_tx_freq 700e6 --uhd_tx_rate 5e6 --uhd_tx_gain 20
> --tran_wavetype SINE --tran_wavefreq 1e6 --tran_amplitude 0.5
> --addmodule waveform

At this point the node1-1 should be transmitting a tone at 1MHz from the 700MHz center frequency. From node1-2, use the UHD spectrum utility to verify the waveform

node1-2> cd uhd/host/build/examples/
node1-2> ./rx_ascii_art_dft --freq 700e6 --rate 5e6 --gain 20 --ref-lvl -40

Record spectrum data to an OML file

Now let's use wiserd to record this spectrum data into a local

node1-2> wiserd
> --uhd_rx_freq 700e6 --uhd_rx_rate 5e6 --uhd_rx_gain 20 --recv_running_time 2000
> --recv_numbins 256 --recv_avgwinlen 5 --recv_oml_servername file --recv_oml_output_type vector
> --addmodule fftmovingavgoml --timed

Wiserd should record spectrum data to file for 2000ms and then stop recording.

The recorded file can ve very large so a short snippet is shown below

protocol: 5
domain: spectrum
start-time: 1432751617
sender-id:
app-name: spectrum
schema: 0 _experiment_metadata subject:string key:string value:string
schema: 1 _client_instrumentation measurements_injected:uint32 measurements_dropped:uint32 bytes_allocated:uint64 bytes_freed:uint64 bytes_in_use:uint64 bytes_max:uint64
schema: 2 spectrum_data sampling:int32 cfreq_MHz:double gain_dB:int32 FFTLength:int32 FFTNum:string FFTBins:[double]
content: text

0.805870        2       1       5000000 700000000.000000        20      256     ---     256 0.00642503052949905 0.00640759989619255 0.00715913623571396 0.00693625304847956 0.00609686318784952 0.00611346587538719 0.00733797857537866 0.00742206443101168 0.00644569378346205 0.00748523231595755 0.00655230600386858 0.006748684681952 0.00692673865705729 0.00592925120145082 0.00748975854367018 0.00621710997074842 0.00608090776950121 0.0055550062097609 0.0057487809099257 0.00720828492194414 0.00618668925017118 0.00473179295659065 0.006808090955019 0.00687119970098138 0.005494792945683 0.00755641097202897 0.0063415477052331 0.00596773438155651 0.00671912264078856 0.00726061593741179 0.00553654972463846 0.00698605040088296 0.00529543263837695 0.00783630926162004 0.00672802329063416 0.00635359063744545 0.00666496902704239 0.00626690546050668 0.00589855946600437 0.00733701791614294 0.00885633658617735 0.00691640749573708 0.00642102723941207 0.00926791410893202 0.00719658425077796 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0.0096791498363018 0.00998857151716948 0.0117274457588792 0.0101575655862689 0.0124989086762071 0.01237382367253^@ 0.0133225293830037 0.0146061507984996 0.0208994746208191 0.0468954369425774 0.122245348989964 0.0262875147163868 0.0151699390262365 0.0129134533926845 0.0126580595970154 0.0127546470612288 0.0141236884519458 0.0128746386617422 0.0113462153822184 0.0139725683256984 0.0149048119783401 0.012725941836834 0.0142481597140431 0.014576974324882 0.0165196731686592 0.0166050866246223 0.0181233920156956 0.0182002373039722 0.0205240771174431 0.0182637479156256 0.0225130878388882 0.0199225898832083 0.022662311792373^@ 0.0272368285804987 0.0229660626500845 0.0206097178161144 0.0252554770559072 0.0277251955121756 0.027890432626009 0.03005550801754 0.0291061010211706 0.0328644625842571 0.0377240218222141 0.0371225923299789 0.0430551692843437 0.0448992624878883 0.0500019602477551 0.055297739803791 0.0620570369064808 0.0687699541449547 0.0800459012389183 0.096101202070713 0.119709715247154 0.151971653103828 0.222265601158142 0.395731300115585 1.8209445476532 0.701657652854919 0.293412864208221 0.186001688241959 0.135782465338707 0.107891581952572 0.0872630029916763 0.0756658166646957 0.0643373876810074 0.0577538087964058 0.053208451718092 0.0474477596580982 0.043580025434494 0.0416424460709095 0.0350464805960655 0.034961711615324 0.0329569280147552 0.0307744555175304 0.0304238144308329 0.0277519728988409 0.026080325245857^@ 0.0244618654251099 0.0233206581324339 0.023502279073 0.0213998667895794 0.0197461675852537 0.0213919542729855 0.0210770349949598 0.0178680755198002 0.0188288316130638 0.0168855395168066 0.0173622630536556 0.0162709001451731 0.0161915346980095 0.01674560084939 0.0157821383327246 0.0147516150027514 0.0129792336374521 0.01588449254632 0.0135742779821157 0.0144895184785128 0.0126562193036079 0.0140249133110046 0.0127318147569895 0.0125512164086103 0.0115098562091589 0.0102976094931364 0.0142459943890572 0.0123602850362659 0.0110908718779683 0.0117047075182199 0.0108433095738292 0.0113961454480886 0.00989516265690327 0.0109618585556746 0.00892620161175728 0.0101382881402969 0.00846627354621887 0.0101864114403725 0.00957665219902992 0.00926020089536905 0.00821538269519806 0.00760462647303939 0.010831995867192^@ 0.00874793529510498 0.00983591936528683 0.0086268512532115 0.00901609845459461 0.00873745605349541 0.00801646523177624 0.00832579005509615 0.00826011598110199 0.00759589159861207 0.00800738204270601 0.00827436801046133 0.00850967969745398 0.00803695525974035 0.00859370641410351 0.00757377874106169 0.00678808754310012 0.00810458604246378 0.00828907825052738 0.0073024220764637 0.00828505866229534 0.00829954538494349 0.00789687223732471 0.00625459849834442 0.00735813518986106 0.00677822157740593 0.00603437423706055 0.00656507024541497 0.00717219989746809 0.00768232485279441 0.00599283492192626 0.00739502254873514 0.00717072654515505 0.00757684791460633 0.00703901331871748 0.00658791046589613 0.00659507792443037 0.00577279180288315 0.00665358593687415 0.00633173156529665 0.00557167362421751 0.00851421989500523

0.806104        2       2       5000000 700000000.000000        20      256     ---     256 0.00689565530046821 0.00628861784934998 0.00648185843601823 0.00669795507565141 0.00584999099373817 0.00637592282146215 0.00665496429428458 0.00677516451105475 0.00625768397003412 0.00584975723177195 0.0060897353105247 0.00563886109739542 0.00706819351762533 0.00657628104090691 0.00634182989597321 0.00633346568793058 0.0062954961322248 0.00681345677003264 0.00627884548157454 0.00565372034907341 0.00675516203045845 0.00734227616339922 0.00573072256520391 0.0063943974673748 0.00608528079465032 0.00676710763946176 0.00617225747555494 0.00553606916218996 0.00660644983872771 0.0063962722197175 0.00743097579106688 0.00628956127911806 0.00731373578310013 0.00724115874618292 0.00646150950342417 0.0066513828933239 0.00803750939667225 0.00523182982578874 0.00641514360904694 0.00818850565701723 0.00636473763734102 0.00712296459823847 0.00614004954695702 0.00618369597941637 0.00591028016060591 0.00637322664260864 0.00655190274119377 0.00639662798494101 0.00541317230090499 0.00741449510678649 0.00761738698929548 0.0070836590602994 0.00605544168502092 0.00635870546102524 0.00694706430658698 0.00656211003661156 0.00666100438684225 0.00627775583416224 0.0116550819948316 0.0100514981895685 0.00824615824967623 0.00756618101149797 0.0078535033389926 0.0101745296269655 0.00904152821749449 0.00695109087973833 0.00740401213988662 0.00704846531152725 0.0077576725743711 0.0071131675504148 0.00850622821599245 0.00610636034980416 0.00661058444529772 0.00847268849611282 0.007558090146631 0.00893115531653166 0.00833071861416101 0.00715811923146248 0.00823779869824648 0.0089316014200449 0.00595288490876555 0.00747732911258936 0.00831372570246458 0.00861002039164305 0.00799854192882776 0.00973799638450146 0.00850083213299513 0.00773866334930062 0.00879448000341654 0.00807567313313484 0.0105824302881956 0.00920506287366152 0.00788669660687447 0.00895833969116211 0.0112238116562366 0.0100678941234946 0.0103527856990695 0.0104455724358559 0.012177424505353 0.0112529918551445 0.0102290874347091 0.0135061638429761 0.0147446822375059 0.018596475943923 0.0414362847805023 0.114830479025841 0.025530856102705 0.0190154518932104 0.0155481668189168 0.0143186058849096 0.0138343144208193 0.014024967327714 0.0143188638612628 0.0134244654327631 0.0132367964833975 0.0148129807785153 0.0141275357455015 0.0152805019170046 0.0149390399456024 0.0163573995232582 0.0169974658638239 0.0169846024364233 0.0175251290202141 0.0187166798859835 0.0194499474018812 0.0228170566260815 0.0220983885228634 0.0203606244176626 0.0218033343553543 0.0210654400289059 0.0256397034972906 0.0221499484032393 0.0251883305609226 0.0291288048028946 0.0301742143929005 0.0299053974449635 0.031312745064497 0.0336895957589149 0.0370108000934124 0.0393577739596367 0.0433414280414581 0.0476785935461521 0.0539706349372864 0.0592275373637676 0.0678910464048386 0.0782939940690994 0.0912498533725739 0.113576114177704 0.150473922491074 0.212990492582321 0.384159237146378 1.74912762641907 0.685468077659607 0.285425901412964 0.179363623261452 0.131207302212715 0.104474768042564 0.0858906656503677 0.074637807905674 0.0646835714578629 0.0561635978519917 0.050263948738575 0.0462885685265064 0.0413284674286842 0.0397013314068317 0.0344642288982868 0.0322929508984089 0.0317045971751213 0.0295128636062145 0.0287306308746338 0.0286615248769522 0.023568470031023 0.0228897500783205 0.0226257108151913 0.0222484599798918 0.022429320961237 0.0206066872924566 0.0198463629931211 0.020149877294898 0.017288027331233 0.0161423590034246 0.0164039433002472 0.0163881666958332 0.0164083652198315 0.0157671608030796 0.0150078013539314 0.0146695794537663 0.0149738965556026 0.0142870601266623 0.0128184454515576 0.0130452159792185 0.0135776726529002 0.0117092151194811 0.0125469844788313 0.0118800457566977 0.0131193473935127 0.0124220326542854 0.0114703755825758 0.0109820328652859 0.011516802944243 0.0124680511653423 0.0113629531115294 0.0102917654439807 0.0101364348083735 0.00984693318605423 0.0115289557725191 0.0102153364568949 0.0101874768733978 0.00997439958155155 0.00883135385811329 0.0104001071304083 0.00914312619715929 0.00772677874192595 0.0100395102053881 0.00981313176453114 0.00869345106184483 0.00866962410509586 0.0086707565933466 0.00890628155320883 0.00784013234078884 0.00858987402170897 0.00826080795377493 0.00816309545189142 0.00844899006187916 0.00860675703734159 0.00816098414361477 0.00893862452358007 0.00668511306867003 0.00604773685336113 0.00760708004236221 0.00612658727914095 0.00698500219732523 0.00720309559255838 0.00738290185108781 0.00822578091174364 0.00712159927934408 0.00688611064106226 0.00610087253153324 0.00795015413314104 0.00696648936718702 0.00737108662724495 0.00663621257990599 0.00606435863301158 0.0070930584333837 0.00753137096762657 0.00686082383617759 0.00658690463751554 0.00619596661999822 0.00581462075933814 0.00712865078821778 0.00663717556744814 0.0064032943919301 0.00607451144605875 0.00634610885754228 0.00608755415305495 0.00666977930814028

Performing the experiment using OEDL

OEDL can be used to automatically perform the experiment. The OEDL code for the experiment is shown below.

defProperty('rx_freq', "800e6", "")
defProperty('rx_rate', "5e6", "")
defProperty('rx_gain', "20", "")
defProperty('recv_oml_output_type', "vector", "")
defProperty('recv_oml_servername', "file", "")
defProperty('tx_freq', "798e6", "")
defProperty('tx_rate', "5e6", "")
defProperty('tx_gain', "20", "")
defProperty('tx_module', "foo", "") # using a random name for an unexisting module
defProperty('rx_module', "foo", "") # so that no module is started, but it can be added later by setting this property
defProperty('del_rx_module', "foo", "")

require './wiserd.rb'

defGroup('sender', "node1-1") do |node|
  node.addApplication("test:app:wiserd") do |app|
    app.setProperty('--uhd_tx_freq', property.tx_freq)
    app.setProperty('--uhd_tx_rate', property.tx_rate)
    app.setProperty('--uhd_tx_gain', property.tx_gain)
    app.setProperty('--addmodule', property.tx_module)
  end
end

defGroup('receiver', "node1-2") do |node|
  node.addApplication("test:app:wiserd") do |app|
    app.setProperty('--uhd_rx_freq', property.rx_freq)
    app.setProperty('--uhd_rx_rate', property.rx_rate)
    app.setProperty('--uhd_rx_gain', property.rx_gain)
    app.setProperty('--recv_oml_output_type', property.recv_oml_output_type)
    app.setProperty('--recv_oml_servername', property.recv_oml_servername)
    app.setProperty('--addmodule', property.rx_module)
    app.setProperty('--delmodule', property.del_rx_module)
  end
end

onEvent(:ALL_UP_AND_INSTALLED) do |event|
  wait 10
  info "Starting the Receiver" 
  group("receiver").startApplications
  info "Starting the Sender"
  group("sender").startApplications
  wait 8
  property.tx_module = "waveform"
  property.rx_module = "fftmovingavgoml"
  for i in 798..802
    property.tx_freq = "#{i}e6"
    wait 1
  end
  property.del_rx_module = "fftmovingavgoml"
  group("sender").stopApplications
  group("receiver").stopApplications
  Experiment.done
end

This experiment consists of a receiver centered at 800 MHz, with the bandwidth of 5 MHz, and the transmitter that runs for 5 seconds, transmitting a SINE waveform centered at frequencies of 798, 799, 800, 801 and 802 MHz for 1 second each. The code needs to be saved in a file named experiment.rb. It's assumed that the ​Wiserd application definition for OEDL is available in the file named wiserd.rb. After imaging the nodes and making sure they are turned on, the experiment can be run using the command

omf exec experiment.rb

When the experiment is finished, the receiver will save the results in a file located at the / directory. The file can then be transferred to a local machine for further processing. For example, the results can be plotted using a simple octave script shown below:

w = dlmread('file', ' ', 10, 1);

i = 1;
while (i <= size(w,1))
  if (max(abs(w(i, :))) == 0)
    w(i,:) = [];
  end
  i = i + 1;
end
imagesc(10*log(w/1000.0))

For the described experiment, octave will then produce the image shown below.