A Novel Signaling Scheme for Blind Unique Identification of Alamouti Space-Time Block-Coded Channel

In this paper, we present a simple signaling scheme to blindly and uniquely identify the Alamouti space-time block-coded channel, first under a noise-free environment, and then, under a complex Gaussian noise environment in which $p$th- and $q$th-order statistics ($p$ and $q$ are coprime) of the received signals are available. In both cases, closed-form solutions to determine the channel coefficients are obtained by exploiting specific properties of the Alamouti space-time block code (STBC) and the linear Diophantine equation theory. Under Gaussian noise, when the length of the received data is finite, we propose to use the semidefinite relaxation (SDR) algorithm to approximate maximum-likelihood (ML) detection so that the joint estimation of the channel and symbols can be efficiently implemented. Simulation results show that while other existing blind methods fail, our signaling scheme works well.