Channel estimation techniques for 5G cellular networks: FBMC and multiuser asynchronous fragmented spectrum scenario

In order to reduce constant exchange of control signalling, relaxed synchronisation is considered for the fifth generation of wireless cellular networks. This requirement combined with dynamic spectrum access has led to reconsider conventional orthogonal frequency division multiple access. Frequency division multiple access for filter bank multicarrier (FBMC) modulation has emerged as a serious contender for these asynchronous fragmented spectrum access scenarios. In this paper, it is demonstrated that the frequency-spreading FBMC receiver architecture is particularly adapted to deal with these scenarios and is robust to severe channel conditions. Channel estimation has however so far only been partially addressed in this context. The challenges of this essential signal processing block are presented in this paper. Interference approximation methods have been applied to the so-called frequency-spreading FBMC receiver to propose and evaluate preamble structures and channel estimation schemes. A flexible preamble structure is finally described and analysed. Copyright (c) 2014 John Wiley & Sons, Ltd.