Spectrally Efficient Cooperative Diversity Protocols Forwireless Networks

We design and analyze spectrally efficient cooperative diversity protocols using multiple relays (say N), which combat the multi-path fading by retransmitting the bit-interleaved coded information transmitted by a source to destination. In the first proposed protocol, called N-relay cyclic protocol, each relay will transmit only a portion of the signal transmitted by the source. In the second protocol, only the relay with the best mutual information will transmit all the source information-thus termed as best-relay protocol. We derive the probability density functions of the mutual information for both of these protocols and using these densities, we analyze the outage probability and outage capacity performances. The results show that the proposed protocols achieve the maximum diversity order N + 1.