Research And Verification Of The Impact Of Useful Signal On RF Self-interference Suppression Performance

Full-duplex refers to the communication equipment to receive and transmit at the same frequency at the same time,compared to time division duplex and frequency division duplex,theoretically doubling the efficiency of spectrum utilization.However,because the equipment receive and transmit signal at the same time and the same frequency,the local transmission signal caused strong self-interference on the local reception.To make the local receiver demodulate the useful signal correctly,it is necessary to perform self-interference suppression first.Self-interference suppression methods are divided into three categories: antenna self-interference suppression,RF self-interference suppression and digital self-interference suppression.At present,the radio frequency self-interference suppression mainly uses the direct power method,that is,directly use the signal power after RF self-interference suppression as the objective function,adaptive adjustment RF reconstruction channel parameters for self-interference suppression,the method does not take into account the impact of useful signals.In this paper,we mainly study the suppression of RF self-interference,and focus on the influence of useful signal on RF self-interference suppression performance and the design of RF self-interference suppression algorithm in the presence of useful signals.The main contents are:First,the present situation of the existing self-jamming suppression technology is introduced,and the limitations of the direct power method in full-duplex RF suppression are analyzed emphatically.Secondly,when the direct power method is used,the influence of the useful signal on the RF self-interference suppression performance is analyzed.It is found that the fluctuation of the useful signal limits the RF self-interference suppression performance.Then,the correlation energy method is put forward.The theoretical analysis shows that the correlation energy method can effectively reduce the influence of the useful signal.The simulation results show that the RF self-interference suppression performance of the correlation energy method is improved more than 20 dB relative to the direct power method when the useful signal fluctuates.Thirdly,the RF self-interference suppression algorithm is designed by using the correlation energy method,and the algorithm is designed and implemented in detail.On the full-duplex software radio platform,the experimental results show that the RF self-interference cancellation of direct power method is the same as the correlation power energy when there is no useful signal but the RF self-interference cancellation of the correlation energy method is improved more than 15 dB relative to the direct power method when the useful signal fluctuates.the correlation energy method is not sensitive about useful signal.The related energy method proposed in this paper has obvious advantages over the direct power method,which solves the influence of the useful signal on the RF self-interference suppression performance,and provides a novel idea for the further development of full-duplex communication.