Row-Monomial Distributed Orthogonal Space-Time Block Codes with Channel Phase Information

Very recently, we proposed the row-monomial distributed orthogonal space-time block codes (DOSTBCs) in [1] and showed that the codes achieved approximately twice higher bandwidth efficiency than the repetition-based cooperative strategy. In [1], we assumed that the relays did not have any channel state information (CSI) of the channels from the source to themselves, i.e. the channels of the first hop. However, we notice that this CSI can be readily obtained at the relays without any additional pilot signals or any feedback overhead. Therefore, in this paper, we assume that the relays have partial CSI of the first hop and use this information to construct the codes. We refer to those codes as the row-monomial DOSTBCs with channel phase information (DOSTBCs-CPI) and derive an upper bound of the data-rate of the codes. This upper bound suggests that the row-monomial DOSTBCs-CPI have higher bandwidth efficiency than the row- monomial DOSTBCs in [1], especially in a cooperative network with many relays. Furthermore, we find the actual row-monomial DOSTBCs-CPI achieving the upper bound of the data-rate.