nrPerfectTimingEstimate

Perfect timing estimation

Description

example

[offset,mag] = nrPerfectTimingEstimate(pathGains,pathFilters) performs perfect timing estimation. To find the peak of the channel impulse response, the function first reconstructs the impulse response from the channel path gains pathGains and the path filter impulse response pathFilters. The channel impulse response is averaged across all channel snapshots and summed across all transmit and receive antennas before timing estimation. The function returns the estimated timing offset offset and the channel impulse response magnitude mag.

Examples

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Define a channel configuration structure using an nrTDLChannel System object. Use delay profile TDL-C from TR 38.901 Section 7.7.2.

tdl = nrTDLChannel;
tdl.DelayProfile = 'TDL-C';

Create a random waveform with a duration of 1 subframe.

tdlInfo = info(tdl);
Nt = tdlInfo.NumTransmitAntennas;
in = complex(zeros(100,Nt),zeros(100,Nt));

Transmit the input waveform through the channel.

[~,pathGains] = tdl(in);

Obtain the path filters used in channel filtering.

pathFilters = getPathFilters(tdl);

Estimate timing offset.

[offset,mag] = nrPerfectTimingEstimate(pathGains,pathFilters);

Plot the magnitude of the channel impulse response and the timing offset estimate.

[Nh,Nr] = size(mag);
plot(0:(Nh-1),mag,'o:');
hold on;
plot([offset offset],[0 max(mag(:))*1.25],'k:','LineWidth',2);
axis([0 Nh-1 0 max(mag(:))*1.25]);
legends = "|h|, antenna " + num2cell(1:Nr);
legend([legends "Timing offset estimate"]);
ylabel('|h|');
xlabel('Channel Impulse Response Samples'); Input Arguments

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Channel path gains of the fading process, specified as an NCS-by-NP-by-NT-by-NR complex matrix, where:

• NCS is the number of channel snapshots.

• NP is the number of paths.

• NT is the number of transmit antennas.

• NR is the number of receive antennas.

Data Types: single | double
Complex Number Support: Yes

Path filter impulse response, specified as an NH-by-NP real matrix, where:

• NH is the number of impulse response samples.

• NP is the number of paths.

Each column of the matrix contains the filter impulse response for each path of the delay profile.

Data Types: double

Output Arguments

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Timing offset in samples, returned as a nonnegative integer. The number of samples is relative to the first sample of the channel impulse response reconstructed from pathGains and pathFilters.

Data Types: double

Channel impulse response magnitude for each receive antenna, returned as an NH-by-NR real matrix.

• NH is the number of impulse response samples.

• NR is the number of receive antennas.

mag inherits its data type from pathGains.

Data Types: single | double