On Sparse Channel Estimation in Aeronautical Telemetry

Abstract

This paper examines the application of sparse estimation techniques for the estimation of a discrete-time equivalent multipath channel in the aeronautical telemetry context. The sensing matrix comprises samples of shaped offset QPSK-TG (a continuous phase modulation) based on the pilot bit sequence currently defined in the aeronautical telemetry standard. Representative algorithms from the three broad classes of sparse estimators were examined side by side using computer simulations to estimate the postequalizer bit error rate (BER). Ideal and nonideal frequency offset synchronization were assumed in the simulations. The results show that the performance of the matching pursuit (MP) algorithms seemed to be better suited to this application in the sense that no additional steps were required and the postequalizer BER of the best MP algorithm was slightly better than that of the other sparse estimation techniques. In the case of both ideal and nonideal frequency offset synchronization, the postequalizer BER achieved by the generalized orthogonal MP algorithm was approximately 1.5 dB better than that obtained using the nonsparse-constrained maximum likelihood channel estimate.