Soft Decode and Forward of MQAM Modulations for Cooperative Relay Channels

A novel approach for extension of soft decode and forward strategy into higher order MQAM modulation is proposed. A new soft mapping function is introduced to map soft bits onto a point in the complex plane. It is shown that the proposed soft decode and forward (SDF) scheme attains the same level of diversity as amplify and forward (AF) scheme while improves the overall system spectrum efficiency through forwarding with higher order modulations. Simulation results show that new scheme outperforms DF for different links conditions.

[1]  Branka Vucetic,et al.  Distributed Turbo Coding With Soft Information Relaying in Multihop Relay Networks , 2006, IEEE Journal on Selected Areas in Communications.

[2]  Luc Vandendorpe,et al.  Soft decode and forward improves cooperative communications , 2007, 1st IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing, 2005..

[3]  Matthew C. Valenti,et al.  Distributed turbo coded diversity for relay channel , 2003 .

[4]  Elza Erkip,et al.  User cooperation diversity. Part I. System description , 2003, IEEE Trans. Commun..

[5]  Aria Nosratinia,et al.  Coded cooperation in wireless communications: space-time transmission and iterative decoding , 2004, IEEE Transactions on Signal Processing.

[6]  Abbas El Gamal,et al.  Capacity theorems for the relay channel , 1979, IEEE Trans. Inf. Theory.

[7]  Elza Erkip,et al.  User cooperation diversity. Part II. Implementation aspects and performance analysis , 2003, IEEE Trans. Commun..

[8]  H. Vincent Poor,et al.  Iterative (turbo) soft interference cancellation and decoding for coded CDMA , 1999, IEEE Trans. Commun..

[9]  Gregory W. Wornell,et al.  Cooperative diversity in wireless networks: Efficient protocols and outage behavior , 2004, IEEE Transactions on Information Theory.

[10]  J. Li,et al.  Decode-amplify-forward (DAF): a new class of forwarding strategy for wireless relay channels , 2005, IEEE 6th Workshop on Signal Processing Advances in Wireless Communications, 2005..

[11]  Xiaodong Li,et al.  Bit-interleaved coded modulation with iterative decoding , 1997, IEEE Communications Letters.