A Hybrid Coding Scheme for Cooperative Networks
- Author(s): Madhavan Vajapeyam;
- Gautam Thatte;
- Urbashi Mitra
- et al.
In this work, communication protocols and encoding schemes are analyzed and designed to achieve diversity and superior probability of decoding error for networks of distributed terminals. In particular, a single source and destination pair are considered with a collection of R cooperating relay nodes in between. Communication protocols and encoding schemes based on methods of amplify-and-forward and decode-and-forward coupled with Alamouti based orthogonal space-time block codes and optimum minimum metric space-time block codes are considered. The achievable diversity of a previously proposed amplify-and-forward/Alamouti method is derived and compared to that of a decode-and-forward scheme. For modest SNRs, the decode-and-forward scheme outperforms the amplify-and-forward based scheme. However, poor source-to-relay link quality can severely impact the decode- and-forward scheme and thus a hybrid scheme is proposed and shown to provide superior performance to the previously two discussed schemes.