Research Of A Fast Search Algorithm For Rf Self-interference Suppression In Full-duplex

Current deployed wireless communication systems employ either a time-division or frequency-division approach to bidirectional communication. This requires dividing the temporal and/or spectral resources into orthogonal resources and results in half-duplex wireless communication systems. The goal of full duplex communication is to consist on the same frequency simultaneously. However, its main obstacle is that the interference from local signals is too stronger than interest signals.In full-duplex mode, there are mainly three ways to cancel self-interference, which are antenna interference, RF interference and digital interference. Based on the demanded indicators, have designed and implemented an RF interference technology which can be applied on full duplex systems. This paper is focused on the theory of gradient search and prediction modules, and their optimization strategies, while C language is used to implement the key technical solutions. The effect of self-cancellation is tested on a full duplex device, and the analysis of results is given.Firstly, the existing cancellation theories and techniques are discussed, especially the detail of RF cancellation algorithms, which provide a reference design idea for this paper. A project’s way to measure gradient search is proposed and quadratic regression module is used to predict two-dimension points under the program’s indicators, and full details of the optimization program is given.Secondly, key modules of RF cancellation quick search algorithm are achieved according the hardware architecture. A detailed design plan with C language is given, including interface informations and processes.Again, soft emulation is carried out on the basis of the detailed design plan. Different scenarios are tested with ZC signals, in which the search path, the gradient region, the prediction step and SNR parameters are tested, and gives a reference to determine parameters.Finally, the performance of the algorithm is verified. With the help of full duplex wireless devices, RF cancellations are tested in different self-interference signal powers. Under a-10 dBm of self-interference signal, 48 dB rejection is achieved, which meets the design requirements.This paper presents a verified technology of RF cancellation using gradient-based prediction. The method can be a theoretical basis to promote a further development of full-duplex communication.