Channel and carrier frequency offset estimation based on projection onto a bidimensional basis

Abstract

Two of the most counterproductive effects that must be dealt with in communication systems in realisticenvironments are carrier frequency offset (CFO) and time-varying channels. These problems are usually addressed byusing independent approaches for each one. This paper introduces an algorithm that attacks both of these effects in ajoint fashion. It is based on a rough compensation of CFO, and after considering that the remaining CFO uncertaintycan be seen as part of the time-varying channel a channel estimation that includes that composite channel is performed.Particularly, the channel estimation based on projection onto a bidimensional basis is shown to be adequate to performthis process. The approach suggested in this paper is illustrated for a superimposed training-based communicationsystem. Simulation results corroborate the validity of the proposed algorithm, where the performance obtained is similarto that achieved for the time-varying channel estimators based on bidimensional basis projection when no CFO is present.