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Performance improvement in channel processing #2

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merged 3 commits into from
Jul 20, 2020
Merged

Performance improvement in channel processing #2

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6b5deda
Improve to generate CIR
hassiweb Jul 12, 2020
9c7a39e
Fix the size of CIR
hassiweb Jul 12, 2020
8032776
improve to apply channel
hassiweb Jul 13, 2020
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56 changes: 30 additions & 26 deletions src/Channel/getChannel.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -312,16 +312,10 @@ function getChannel(nbSamples::Int,channelModel::ChannelModel,randSeed=-1)
freq = channelModel.samplingFreq;
# --- Ensuring additional delay for proper interpolation
delay = channelModel.delayProfile .+ fdGap;
cir = zeros(Complex{Float64}, nbSamples, delaySpread + sS);
for indexTime = 1 : 1: nbSamples
for k = 1 : 1 : delaySpread + sS
# --- Each index is superimposition of all timed compondent
for ∂ = 1 : 1 : nbTaps
# --- Shannon interpolation with sinc. on sincSupport
cir[indexTime,k] += powerLin[∂] * raylAmpl[indexTime,∂] * sinc.(pi*(k/freq - delay[∂]) * freq);
end
end
end
# --- Shannon interpolation with sinc. on sincSupport
shannonInterp = sinc.(pi.*(transpose(1:delaySpread+sS)./freq .- delay) .* freq);
# --- Each index is superimposition of all timed compondent
cir = transpose(powerLin) .* raylAmpl[1:nbSamples] * shannonInterp;
return ChannelImpl(1,cir,channelModel,powerLin,randSeed);
else
# ----------------------------------------------------
Expand Down Expand Up @@ -356,7 +350,9 @@ sigChan : applyChannel(sigId,channelImpl)
# ---
# v 1.0 - Robin Gerzaguet.
"""

function applyChannel(sigId,channelImpl)

if !Bool(channelImpl.timeVarying)
# --- Classic convolution
return sigChan = conv(sigId,channelImpl.cir);
Expand All @@ -370,26 +366,34 @@ function applyChannel(sigId,channelImpl)
nbTaps =size(channelImpl.cir,2);
nbOut =length(sigId)+nbTaps
sigChan = zeros(Complex{Float64},nbOut)
# n is time index of output, δ is lag index
for n = 1 : 1 : length(sigId)
# --- At beginning, not possible to have all index
nbMaxTap = min(n,nbTaps);
# --- Classic time domain convolution
for δ = 1 : 1 : nbMaxTap
sigChan[n] += channelImpl.cir[n,δ] * sigId[n-δ+1];
end
end
# At the end we have zero
timeVaryingConv!(sigChan, channelImpl.cir, sigId, nbTaps)

# At the end we have zero
buffEnd = zeros(Complex{Float64},nbTaps *2);
buffEnd[1:nbTaps] = sigChan[1:nbTaps];
for n = 1:nbTaps
# --- Classic time domain convolution
for δ = 1 : 1 : nbTaps
sigChan[length(sigId)+n] += channelImpl.cir[end,δ] * buffEnd[n+nbTaps-δ+1];
end
end
timeVaryingConvTail!(sigChan, channelImpl.cir, buffEnd, length(sigId), nbTaps)

return sigChan;
end
end

function timeVaryingConv!(sigChan, cir, sigId, nbTaps)
# n is time index of output, δ is lag index
for n = 1:length(sigId)
# --- At beginning, not possible to have all index
nbMaxTap = min(n,nbTaps);
# --- Classic time domain convolution
for δ = 1:nbMaxTap
@inbounds sigChan[n] += cir[n,δ] * sigId[n-δ+1];
end
end
end

function timeVaryingConvTail!(sigChan, cir, buffEnd, nbSigSamples, nbTaps)
for n = 1:nbTaps
# --- Classic time domain convolution
for δ = 1 : 1 : nbTaps
@inbounds sigChan[nbSigSamples+n] += cir[end,δ] * buffEnd[n+nbTaps-δ+1];
end
end
end