Adaptive Randomized Distributed Space-Time Coding in Cooperative MIMO Relay Systems

TL;DR

This paper introduces an adaptive randomized distributed space-time coding scheme for cooperative MIMO relay systems, employing feedback and MMSE techniques to enhance performance and reduce complexity.

Contribution

It proposes a novel adaptive randomized DSTC scheme with a feedback-based randomized matrix and develops algorithms for parameter optimization.

Findings

Significant performance improvements over existing DSTC schemes.

Effective reduction in computational complexity with the stochastic gradient algorithm.

Derivation of the upper bound of error probability for the proposed scheme.

Abstract

An adaptive randomized distributed space-time coding (DSTC) scheme and algorithms are proposed for two-hop cooperative MIMO networks. Linear minimum mean square error (MMSE) receivers and an amplify-and-forward (AF) cooperation strategy are considered. In the proposed DSTC scheme, a randomized matrix obtained by a feedback channel is employed to transform the space-time coded matrix at the relay node. Linear MMSE expressions are devised to compute the parameters of the adaptive randomized matrix and the linear receive filter. A stochastic gradient algorithm is also developed to compute the parameters of the adaptive randomized matrix with reduced computational complexity. We also derive the upper bound of the error probability of a cooperative MIMO system employing the randomized space-time coding scheme first. The simulation results show that the proposed algorithms obtain significant performance gains as compared to existing DSTC schemes.