Long term evolution (LTE) uplink canonical channel estimation
View Patent ↗A method and system for canonical channel estimation in the Long Term Evolution uplink where a multi-frequency signal is generated and then converted to frequency spectrum which is then convolved in the frequency domain with a truncated window function to obtain a time domain channel impulse response. The time domain channel impulse response can be then transformed to a frequency domain to produce a down sampled user channel response, which can be then linearly interpolated to provide a channel estimate for a plurality of subcarriers. Such an approach achieves channel estimation within Long Term Evolution at only canonical locations to reduce complexity without loss in channel entropy.
1. A method for canonical channel estimation in a receiver of a wireless network utilizing a digital signal processor, said method comprising:
utilizing the digital signal processor to match a sequence to transmitted pilot symbols to produce a frequency spectrum, Y(ω)=X(ω)*P*(ω), wherein X is the obtained signal in a frequency domain and P is a generated Zadoff-Chu signal matched to pilot symbol;
obtaining a down sampled time-domain channel impulse response (CIR) per user, Y UserDS (ω), by convolving said frequency spectrum, Y(ω), with a truncated windowing function, W User (ω), in the frequency domain utilizing equation Y UserDS (ω)=Y(ω)*W User (ω);
performing phase correction in the frequency domain on said CIR, Y UserDS (ω), utilizing Y′ UserDS (ω)·exp(j(0:N)2πδ∫ User ), wherein δ∫ User is a user dependent phase shift and N is the number of subcarriers;
linearly interpolating said phase corrected CIR, Y UserDS (ω), to produce channel estimates at all subcarrier locations, [Y User (ω 4k-0 ) . . . Y User (ω 4k-3 )].
2. A non-transitory computer-readable medium for canonical channel estimation, said non-transitory computer-readable medium embodying computer program code, said computer program code comprising computer executable instructions configured to:
match a sequence to transmitted pilot symbols to produce a frequency spectrum, Y(ω)=X(ω)*P*(ω), wherein X is the obtained signal in a frequency domain and P is a generated Zadoff-Chu signal matched to pilot symbol;
obtain a down sampled time-domain channel impulse response (CIR) per user, Y UserDS (ω), by convolving said frequency spectrum, Y(ω), with a truncated windowing function, W User (ω), in the frequency domain utilizing equation Y UserDS (ω)=Y(ω)*W User (ω);
perform phase correction in the frequency domain on said CIR, Y UserDS (ω), utilizing Y′ UserDS (ω)·exp(j(0:N)2πδ∫ User ), wherein δ∫ User is a user dependent phase shift and N is the number of subcarriers;
linearly interpolate said phase corrected CIR, Y UserDS (ω), to produce channel estimates at all subcarrier locations, [Y User (ω 4k-0 ) . . . Y User (ω 4k-3 )].
3. The non-transitory computer-readable medium of claim 2 , wherein said truncated windowing function comprises a particular size.
4. The non-transitory computer-readable medium of claim 3 , wherein said particular size is limited to said plurality of user subcarriers.
5. A system for canonical channel estimation, said system comprising:
a data processing device having a central processor; and
a non-transitory computer-readable medium embodying computer code, said non-transitory computer-readable medium being implemented on said data processing device, said computer program code comprising instructions executable by said central processor and configured to:
match a sequence to transmitted pilot symbols to produce a frequency spectrum, Y(ω)=X(ω)*P*(ω), wherein X is the obtained signal in a frequency domain and P is a generated Zadoff-Chu signal matched to pilot symbol;
obtain a down sampled time-domain channel impulse response (CIR) per user, Y UserDS (ω), by convolving said frequency spectrum, Y(ω), with a truncated windowing function, W User (ω), in the frequency domain utilizing equation Y UserDS (ω)=Y(ω)*W User (ω);
perform phase correction in the frequency domain on said CIR, Y UserDS (ω), utilizing Y′ UserDS (ω)·exp(j(0:N)2πδ∫ User ), wherein δ∫ User is a user dependent phase shift and N is the number of subcarriers;
linearly interpolate said phase corrected CIR, Y UserDS (ω), to produce channel estimates at all subcarrier locations, [Y User (ω 4k-0 ) . . . Y User (ω 4k-3 )].