On Preambles With Low Out of Band Radiation for Channel Estimation

TL;DR

This paper introduces novel preamble designs for channel estimation that significantly reduce out-of-band radiation while balancing estimation accuracy, applicable to single and multi-carrier systems.

Contribution

It proposes two convex optimization-based techniques for designing low OOB radiation preambles and extends their application to multi-carrier systems with a trade-off analysis.

Findings

Preambles achieve 10-35 dB lower OOB radiation than existing methods.

There is a fundamental trade-off between estimation accuracy and OOB radiation.

The designed preambles improve channel estimation for MIMO GFDM systems.

Abstract

In this paper, we investigate preamble designs for channel estimation, that jointly address the estimation efficiency in terms of MSE of the channel estimates, and the OOB radiation of the transmit preambles. We provide two novel design techniques, based on a convex optimization problem, to obtain optimal preambles for a single carrier and provide a juxtaposition based method to extend their application to multi-carrier systems. The obtained preambles are shown to have 10 dB to 35 dB lower OOB radiation than the existing preamble based estimation techniques. We also show the fundamental trade-off between the estimation efficiency and the OOB radiation and highlight that the improved OOB performance comes at a cost of increased estimation error. Finally, as a case study, the estimated channel values are used in equalization of a MIMO GFDM system that is aimed for transmit diversity.