The extended-Alamouti space-time block code is full-rate like the celebrated Golden code and it can be used for differential modulation like the Alamouti’s scheme, which is only half-rate. It is thus fit to use for inter-vehicular communications over rapidly varying mobile channels, since its differential version does not require channel state information (CSI) to be known at the receiver. Both transmitter and receiver are each equipped with two antennas. A differential encoding scheme is used across two consecutive 4D symbol intervals. Each entry of the 2x2 transmit matrix simultaneously carries two 2D symbols taken from a phase-shift keying (PSK) signal constellation and they are separated by irrational coefficients in a novel way to be revealed in the body of the paper. No knowledge of the channel state information (CSI) is required. Noncoherent demodulation is applied at the reception. The performance of the differential extended-Alamouti space-time block code is evaluated by way of computer simulations and compared with that of differential Alamouti. Finally, using the new code for inter-vehicular communication is proposed with confidence.

Keywords: Differential extended-Alamouti space-time block coding, Golden code, Inter-vehicular communications, Noncoherent demodulation