The Power Allocation Research In Full-Duplex Relaying

With the continuous development of communication technology, the number of users and the demand for the quality of communication service are continuously increasing. Taking full advantage of the scarce wireless channel resources has always been a problem to be solved, which can expand the channel transmission capacity and improve spectral efficiency and the quality of service. The technology of relay has shown a strong advantage that it can enhance the wireless coverage and the reliability and availability of system.The communication node can work at full-duplex or half-duplex mode. The half-duplex node uses two orthogonal resources to deal with signal simultaneously, which would reduce the spectral efficiency. The full-duplex node can receive and transmit signal at the same time or frequency. The full-duplex can improve the shortcomings of half-duplex, but it will generate self-interference by its own reasons. With the development of self-interference cancellation technology, it is possible to apply the full-duplex technology. Full-duplex combines with relay technology, which can realize the complementary advantages, further improve system performance and meet the needs of communication development.This article describes the application of full-duplex technology on the relay system. It studies the optimal power allocation problem of full-duplex unidirectional and bidirectional relay system. The performance analyses and simulation results of all power allocation schemes are showed here.Firstly, for amplify-and-forward and decode-and-forward relay, power allocation algorithm under different conditions were summarized in a one-way full-duplex wireless relay system with direct link. Also it solves the break-even point of capacity between full-duplex and half-duplex system. Power allocation algorithm contains uniform power allocation, power allocation with individual constraints and power allocation with a sum constraint. Compared with uniform power allocation, power allocation with individual constraints or a sum constraint could gain an optimistic performance.Secondly, it studies the power allocation of full-duplex two-way relay system. The model oftwo-way relaying uses analog network coding, and residual self-interference makes use of a more realistic model. In addition to introduce of convex optimization matlab toolbox gpposy to allocate power at each node, it proposes asymmetric and symmetric power allocation algorithm by virtue of the idea of bisection for the specific two-way relay environment. Compared with toolbox gpposy, those two sub-optimal allocation algorithms pay a premium in the form of performance gain, it has some practical significance with reduced complexity.