Center for Embedded Network Sensing

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.