Cao Xuehong

Minimum transmit power under/considering relay selection for asymmetric two-way relaying networks

Two-way amplify-and-forward (AF) relaying networks have been widely studied because of their simplicity and high spectral efficiency characteristics. Power allocation (PA) and relay selection (RS) for two-way AF relaying systems are of particular interest. However, most of the previous studies only consider the PA and RS for these systems with symmetric traffic requirements. In this study, the authors’ focus on the minimum transmit power (MTP) under/considering RS for asymmetric two-way relaying networks. The authors’ derive the MTP required for two-way AF relaying transmission with asymmetric traffic requirements, and propose an optimal RS criterion based on the derived MTP. First, the outage probability (OP) of two-way relaying transmission based on statistical channel state information (CSI) is derived. Then, by converting a geometric programming to a convex optimisation problem, the closed-form solution of the PA aiming at minimising total transmit power under the OP constraints is obtained. Lastly, a distributed RS criterion based on MTP is proposed. In addition, the proposed RS scheme only needs local statistical CSI rather than instantaneous CSI, which makes it simple in implementation. Numerical results demonstrate that the proposed scheme can significantly decrease the power consumption under the predefined OP constraints.

A hierarchical block matching algorithm in depth extraction for binocular vision

The stereo matching algorithm for binocular stereo vision is a critical and challenge issue in the field of computer vision, which may has lower matching quality or higher time complexity. To improve that, a hierarchical multi-resolution block matching algorithm for high-resolution image pair is proposed in the paper. Two windows with different size are adopted to improve the matching accuracy in the low texture region. The experimental results show that, the testing image pair at resolution 1240x1110 with the disparity range 30~45, the matching speed is improved by 7~10 times with better results compared to the traditional regional matching algorithm.