Leveraging Coherent Distributed Space-Time Codes for Noncoherent Communication in Relay Networks via Training

TL;DR

This paper proposes a training-based strategy for noncoherent relay network communication that improves performance over differential coding, extending to asynchronous networks with OFDM.

Contribution

It introduces a training, estimation, and detection approach for noncoherent relay networks that enhances existing coherent distributed STBCs and extends to asynchronous scenarios.

Findings

Outperforms distributed differential space-time coding in simulations

Effective in asynchronous relay networks with OFDM

Achieves comparable diversity order with simple training

Abstract

For point to point multiple input multiple output systems, Dayal-Brehler-Varanasi have proved that training codes achieve the same diversity order as that of the underlying coherent space time block code (STBC) if a simple minimum mean squared error estimate of the channel formed using the training part is employed for coherent detection of the underlying STBC. In this letter, a similar strategy involving a combination of training, channel estimation and detection in conjunction with existing coherent distributed STBCs is proposed for noncoherent communication in AF relay networks. Simulation results show that the proposed simple strategy outperforms distributed differential space-time coding for AF relay networks. Finally, the proposed strategy is extended to asynchronous relay networks using orthogonal frequency division multiplexing.