Extended Orthogonal Space-time Block Coding Research Articles

MIMO Wiretap Channels Based on Generalized Extended Orthogonal STBCs and Feedback

This paper presents a two-phase process consisting of advantage distillation (AD) and information reconciliation for achieving secret sharing over a wiretap channel. By using the feedback bits from the legitimate receiver to transmitter, we propose a novel AD scheme for multiple-input multiple-output (MIMO) wiretap (MIMO-WT) channels. We first generalize the extended orthogonal space-time block codes (EO-STBCs). Then, based on the generalized EO-STBCs (GEO-STBCs) and channel state information (CSI), the feedback bits transmitted from the legitimate receiver to the transmitter are generated to increase the signal-to-noise ratio (SNR) gap between the legitimate receiver and the eavesdropper. Simulation results show that the feedback performance gain of the proposed AD scheme increases rapidly with the number of transmit antennas and the value of SNR. A bit error rate (BER) performance gain up to 5.5 dB is obtained by the legitimate receiver over the eavesdropper at the BER of $10^{-5}$ . Moreover, it is also shown that the secrecy capacity of two-way MIMO-WT channels with feedback grows rapidly in low SNR regime and grows slowly in high SNR regime.

Closed-loop extended orthogonal space-time block codes for three and four transmit antennas

Complex orthogonal space-time block codes (STBCs) with linear processing for more than two transmit antennas cannot achieve a full rate in multiple-input and multiple-output (MIMO) channels. However, at the expense of losing some degree of diversity advantage, it is possible to achieve a full rate or even rates higher than one for any number of transmit antennas. In this letter, we propose new closed-loop extended orthogonal STBCs (EO-STBCs) for three and four transmit antennas. We show that the schemes can achieve a full transmit diversity with linear processing, and they outperform the previous closed-loop STBCs. In addition, we investigate the closed-loop EO-STBCs with receive antenna selection. It is shown that for four transmit antennas and up to three receive antennas, performance gains of up to 5.8 dB are obtained over the closed-loop EO-STBCs without antenna selection.