Distributed Interleave-Division Multiplexing Space-Time Codes for coded relay networks

In this paper the application of the recently proposed interleave-division multiplexing space-time codes (IDM-STC) in coded relay networks is investigated. IDM-STC are a very flexible scheme to exploit space diversity with the benefits of IDM such as robustness against asynchronism and efficient iterative detection. While IDM-STC have been investigated for MIMO systems, relay networks induce additional constraints like imperfect decoding at the relay and limited cooperation. Consequently, not only the choice of the diversity scheme, but also the applied relay functionality significantly influences the overall performance. In this paper different relay schemes in combination with IDM-STC are considered for coded relay networks. Amplify-forward (AF) does not assume any signal processing at the relays and just forwards the received signal. Decode-forward (DF) fully decodes the received signal which can lead to error propagation. Another relaying scheme called estimate-forward (EF), which combines the advantages of AF and DF, was recently extended to coded systems and is called decode-estimate-forward (DEF). A coded IDM-STC relay system with different relay schemes is investigated to show the good performance of IDM-STC combined with DEF in realistic scenarios with small overhead and robustness against asynchronism.