Pilot Sequence Design for Spectral Compactness and Channel Estimation in OFDM

Abstract

The spectrally compact pilot waveform that exhibits small power spectral sidelobes and thus high spectral compactness while achieving accurate channel estimation is desirable for orthogonal frequency division multiplexing systems. However, existing pilot waveforms either suffer large power spectral sidelobes or can achieve high spectral compactness only when the length of the carried pilot sequence is limited to a constrained set of non-prime numbers, particularly those containing a large positive integer power of two as a factor. In this paper, new procedures are proposed for designing more pilot sequences with a broader choice of sequence lengths, so that spectrally compact pilot waveforms can be constructed to achieve optimal channel estimation on quasi-static multipath channels.