At The Same Time, The Research Of The Same-frequency Full-duplex Adaptive Interference Cancellation System

With the rapid development of mobile communications,5G communication standard is also gradually developed.Co-time Co-frequency Full Duplex(CCFD),which is one of the key technologies of 5G communication,has also got widespread concerns at home and abroad.This paper takes deep study with the cancellation system of CCFD under the background with standard communication band of LTE.Compared with the software platforms such as WARP,NI PXIe-8133,USDR,etc.,the research results of this paper can provide the basis for the integration and miniaturization of the practical application.The main contents of this article are as follows:(1)A scheme of CCFD canceling system with 2.4GHz operating frequency is designed.This scheme is based on RF reconstruction analog auto-jamming cancellation technology.Firstly,the transmitted signal,which is reference signal,is directly quadrature-mixed self-interference signal.Then,the phase information of self-interference signal is extracted by FPGA control system.And next using digital vector modulator to reconstruct the transmit reference signal.Finally,it can realize self-interference signal cancellation.The feasibility of the scheme is verified by the simulation of Matlab software,and the effect is better.(2)This paper designs and implements each module in the cancellation system,including self-interference cancellation module,self-interference signal detection module and control module.The key components of quadrature coupler,vector modulator,combiner(quadrature),quadrature mixer,RF amplifier,active low-pass filter,error amplifier and FPGA control circuit are mainly developed.(3)The whole system software composed of AD,DA,amplitude-phase calculation module is implemented based on the FPGA and the feasibility of the CCFD cancellation scheme is also verified.