On the construction of high-rate block-orthogonal multisensor block codes

In frequency-selective media, orthogonal space-time block codes (or alternatively their space-frequency counterparts) fail to achieve the maximum possible space-frequency diversity. The paper first proposes block-orthogonal multisensor codes (i.e., either space-time or space-frequency codes) for frequency-selective channels by considering data blocks rather than symbols as transmission units. These codes can be derived from their narrowband versions, namely the orthogonal space-time block codes proposed by S.M. Alamouti (IEEE J. on Selected Areas in Commun., vol.16, p.1451-8, 1998), V. Tarokh et al. (IEEE Trans. on Inf. Theory, vol.45, p.1456-67, 1999), and G. Ganesan and P. Stoica, and maximally exploit the available space-frequency diversity. For 3and 4-transmit sensor configurations, the block orthogonal codes derived from the recently proposed rate-(3/4) symbol orthogonal codes (Ganesan and Stoica, "Signal Processing Advances in Wireless and Mobile Communications", Prentice-Hall, p.59-88, 2000; IEEE Trans. on Inf. Theory, vol.47, p.1650-6, 2001) have structures that are especially convenient for channel response estimation.