Research On Channel Estimation Algorithm Of MIMO-PLC

Multi-path fading and noise interference in PLC channel are the main factors leading to its reliability decline.Channel estimation can obtain real-tim e channel state information and ensure the correct recovery of transmitted signal s.In order to improve communication reliability,this paper studies the channel estimation algorithm in MIMO-PLC system.Firstly,the channel and noise model of MIMO-PLC system are constructed,and the channel capacity is simulated.Combined with PLC channel characteristics,the advantages of OFDM technology and PLC system are analyzed,and the principle and performance of three kinds of PLC channel estimation methods are described.In order to facilitate engineer ing implementation,this paper chooses the PLC channel estimation method based on pilot frequency as the main research object.Secondly,this paper analyzes theoretically the LS algorithm,DFT algorithm and the performance of the improved DFT algorithm,in view of the traditional channel estimation method requires continuous send guide frequency spectrum resource waste caused by the problem,put forward the DF estimat ion based on linear transform,to the above methods in SISO-PLC system simulation,the results proved that compared with the traditional LS algorit hm,The DF estimation proposed in this paper can track the channel characteristi cs more accurately and improve the communication rate of PLC system.Then,in order to solve the channel interference problem of MIMO-PLC system,a pilot structure based on orthogonal subcarrier position is designed,which converts the channel estimation problem of MIMO-PLC into the common SISO-PLC channel estimation problem,but the pilot structure has the defect of subcarrier resource waste.After the channel parameters at pilot are obtained,the channel parameters at data are obtained through interpolation algorit hm,then the principle and performance of the classical interpolation algorithm are analyzed,and an improved second-order interpolation algorithm is proposed to solve the correlation difference of the traditional second-order interpolat ion algorithm,and the simulation results prove the effectiveness of the method.Finally,aiming at the resource waste defect of pilot based on orthogonal subcarrier position,combined with the complex orthogonal characteristics of Alamouti code,the orthogonal pilot structure based on orthogonal code in STBC-MIMO-PLC system is given,which brings diversity gain to the system and improves the frequency utilization ratio.The simulation structure curve of mean square error of the system shows that,compared with the pilot based on orthogonal position,the pilot structure shows better estimation performance.In order to further simplify MMSE algorithm,PLC channel autocorrelation matrix is decomposed by SVD principle.Simulation results show that SVD algorithm has better estimation performance than LS algorithm.