ti_mo
82 lines
2.6 KiB
Matlab
82 lines
2.6 KiB
Matlab
function res = perform_access_analysis(satSim, queryTime, carrierFrequency)
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sat = satSim.sat;
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ue = satSim.ue;
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ac = access(sat,ue);
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[status,timeout] = accessStatus(ac);
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statusIdx = find(status,1);
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if isempty(statusIdx)
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disp("Position estimation cannot be performed " + ...
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"as there is no access between satellite and UE.")
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return
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end
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delete(ac)
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[~,el,r] = aer(ue,sat,queryTime);
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res.distanceToSatellite = r;
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res.elevationAngleToSatellite = el;
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if nargin < 3
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carrierFrequency = 2.4e9;
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end
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[fshift,~,dopplerInfo] = dopplershift( ...
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sat,ue,queryTime,Frequency=carrierFrequency);
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res.rangeRate = -1*dopplerInfo.RelativeVelocity;
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[satPos,satVel] = states(sat,queryTime,CoordinateFrame="ecef");
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res.satPos = satPos;
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res.satVel = satVel;
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res.fshift = fshift;
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if ~isfinite(fshift)
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res.satelliteVisible = false;
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return;
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end
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res.satelliteVisible = true;
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rng(0)
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lightspeed = physconst("lightspeed");
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frameDurInSeconds = 10e-3;
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delayInSeconds = r/lightspeed;
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nFrames = ceil(delayInSeconds/frameDurInSeconds) + 1;
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carrier = nrCarrierConfig;
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pdsch = nrPDSCHConfig;
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pdsch.DMRS.DMRSAdditionalPosition = 2;
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[txWaveform,waveformInfo] = ...
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HelperNRNTNThroughput.generatePDSCHWaveform( ...
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carrier,pdsch,struct,eye(pdsch.NumLayers),"double",carrier.SlotsPerFrame*nFrames);
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refGridAllSlots = waveformInfo.ResourceGrid;
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delayInSamples = delayInSeconds.*waveformInfo.SampleRate;
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integDelaySamples = floor(delayInSamples);
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fracDelaySamples = (delayInSamples - integDelaySamples);
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staticDelay = dsp.Delay(Length=integDelaySamples);
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variableFractionalDelay = dsp.VariableFractionalDelay( ...
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InterpolationMethod="Farrow", ...
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FarrowSmallDelayAction="Use off-centered kernel", ...
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MaximumDelay=1);
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delayedTx = staticDelay(txWaveform);
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delayedTx = variableFractionalDelay(delayedTx,fracDelaySamples);
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channel = p681LMSChannel;
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channel.SampleRate = waveformInfo.SampleRate;
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channel.CarrierFrequency = carrierFrequency;
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channel.SatelliteDopplerShift = fshift;
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channel.MobileSpeed = 0;
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channel.ElevationAngle = el;
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channel.RandomStream = "mt19937ar with seed";
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rxWaveform = channel(delayedTx);
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freqSearch = 0.999*fshift:sign(fshift):1.001*fshift;
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[delayEstSamples,fshiftEst] = HelperNRNTNThroughput.jointTimeFreq( ...
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carrier,rxWaveform,refGridAllSlots,freqSearch);
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res.rangeEst = delayEstSamples*lightspeed/waveformInfo.SampleRate;
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res.rangeRateEst = -1*fshiftEst*lightspeed/carrierFrequency;
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end |