A Non-orthogonal Distributed Space-Time Coded Protocol Part II: Code Construction and DM-G Tradeoff

This is the second part of a two-part series of papers. In this paper, for the generalized non-orthogonal amplify and forward (GNAF) protocol presented in Part-I, a construction of a new family of distributed space-time codes based on Co-ordinate Interleaved Orthogonal Designs (CIOD) which result in reduced Maximum Likelihood (ML) decoding complexity at the destination is proposed. Further, it is established that the recently proposed Toeplitz space-time codes as well as space-time block codes (STBCs) from cyclic division algebras can be used in GNAF protocol. Finally, a lower bound on the optimal Diversity-Multiplexing Gain (DM-G) tradeoff for the GNAF protocol is established and it is shown that this bound approaches the transmit diversity bound asymptotically as the number of relays and the number of channels uses increases.