Differential Distributed Space-Time Coding with Imperfect Synchronization

TL;DR

This paper introduces a robust differential distributed space-time coding scheme for relay networks that maintains high diversity and symbol-by-symbol decoding performance despite synchronization errors, without needing channel information.

Contribution

It proposes a new differential encoding and decoding method for D-DSTC systems with two relays that is resilient to synchronization errors and does not require channel knowledge.

Findings

Achieves maximum diversity with symbol-by-symbol decoding.

Robust against various synchronization errors.

Performance remains stable despite synchronization imperfections.

Abstract

Differential distributed space-time coding (D-DSTC) has been considered to improve both diversity and data-rate in cooperative communications in the absence of channel information. However, conventionally, it is assumed that relays are perfectly synchronized in the symbol level. In practice, this assumption is easily violated due to the distributed nature of the relay networks. This paper proposes a new differential encoding and decoding process for D-DSTC systems with two relays. The proposed method is robust against synchronization errors and does not require any channel information at the destination. Moreover, the maximum possible diversity and symbol-by-symbol decoding are attained. Simulation results are provided to show the performance of the proposed method for various synchronization errors and the fact that our algorithm is not sensitive to synchronization error.