Anti-jamming Performance Analysis Of The MIMO System Uplink Based On Channel Estimation

In recent years,wireless communication technology has been developed rapidly.The development of wireless communication technology has made people's daily life more convenient.The MIMO system is one of the most important technologies in the next generation of wireless communication.The advantages of fast speed,low delay and large capacity of the MIMO system are favored by people.However,the normal communication and the safety of communication of legitimate users will be greatly affected because of the presence of jamming signal,people still hope a securer communication based on various advantages of the MIMO system.Therefore MIMO anti-jamming technology is valued by many experts and scholars.So far,among the current MIMO anti-jamming technologies,the use of pilot channel estimation technology to resist jamming signal is one of the main anti-jamming methods at present.In this paper,the anti-jamming of pilot channel estimation is introduced firstly and then the optimized method of pilot retransmission to anti-jamming and optimized method of joint channel estimation to anti-jamming are introduced respectively,and the achievable speed is used as a measurement index to analyze the anti-jamming performance of the system.The main research work of this paper is as follows:Firstly,the current development of MIMO technology,channel estimation technology and anti-jamming technology at home and abroad are introduced.The channel estimation algorithm can be divided into three types judged by Whether the pilot sequence is used in the channel estimation: pilot channel estimation method,semi blind channel estimation method and blind channel estimation method.In the pilot channel estimation,the least square(LS)algorithm and the minimum mean square error(MMSE)algorithm are introduced.In blind estimation,the blind estimation based on virtual subcarriers is studied.Semi blind estimation and least mean square half blind estimation algorithm based on subspace are mainly studied in semi blind estimation.Secondly,the MIMO anti-jamming method by channel estimation existed is used to take different pilot retransmission strategies to resist jamming signal when there are random jamming signal and deterministic jamming signal.To measure the algorithm performance of the proposed pilot retransmission optimization strategy,the performance of the three cases of deterministic jamming signal,random jamming signal and no pilot retransmission is analyzed by using the reachable rate of the legitimate users as the measurement index.The simulation results show that,whether in the case of random jamming signal or deterministic jamming signal,the strategies adopted can weaken the adverse effects of intentional jamming signal in the system,improve the achievable rate of legitimate users and enhance the anti-jamming performance of the system.Thirdly,when the power of the interference signal is large,the anti-jamming effect of the pilot estimation is worse.In view of this situation,the optimized method of joint channel estimation of the legitimate user channel and the jamming channel is introduced to fight against the jamming signal.It takes the advantage of the approximate characteristics of MIMO system and gets the large scale approximate expression of effective SINR ?,and analyzes the performance under the optimal RZF receiver and the strong jamming system.The achievable rate of legitimate users is used as the measurement to compare the anti-jamming performance to ZF filter,MMSE filter and joint channel estimation from two aspects of the number of antennas and the power of jamming signal respectively.The experimental results show that when the signal-to-noise ratio is different,with the increase of the number of antennas in the MIMO system,the achievable rate by the optimized joint channel estimation anti-jamming method is greater than the minimum mean square error filter(MMSE),zero forcing filter(ZF)method and joint channel estimation method.In the two cases of disturbance power change,the rate of reaching the optimal anti jamming method by joint channel estimation is far higher than the other three methods.In other words,the proposed joint channel estimation optimization method makes the legitimate users achieve higher reachable rate and better anti-jamming result.