Research On Key Technologies Of Millimeter Wave LoS-MIMO System

In this paper,the key technologies of single-carrier multi-input multi-output MIMO system in line-of-sight LoS environment are studied.It has potential application prospects in high-speed data transmission in fixed-broadband wireless access FWA and other applications such as land-based point-to-point communication,satellite communication and other applications.Frequency-selective fading,inter-symbol interference and inter-stream interference in broadband and high-speed communication greatly limit the performance of current millimeter-wave communication systems in high-rate transmission.Based on this,this paper will analyze the relevant technologies of LoS-MIMO communication system according to the order of channel,antenna and equalization mode.The main research content is divided into three parts.Firstly,starting from the model of millimeter-wave LoS-MIMO communication system,each module of LoS-MIMO communication system is introduced,and the Rummler channel model is introduced.Based on its channel capacity theory,and then derive the incense its channel capacity theory to LoS-MIMO system capacity analysis,and gives the essay focuses on the study of the single carrier frequency domain equalization method 2× 2 LoS-the system capacity of MIMO transmission system of the example,finally,the channel capacity Rummler channel model under simulated,through theoretical derivation and analysis of the results of simulation frequency selective fading channel influence on channel capacity and system performance.Secondly,a joint antenna array optimization method under frequency selective fading is proposed.Based on the influence of antenna array on the performance of LoS-MIMO system and the design basis of antenna array,it is deduced that the performance of array depends on the number of array elements,the weight vector used and the geometry of array.By observing the theoretical derivation and simulation results,notice the array output is a function of antenna weights and geometric shapes,depending on the current antenna array,the existing research,basic introduction and comparison of antenna array weighted algorithm,simple phase weighted method is the most simple weighted method,minimum mean square error(MMSE weighted algorithm,for the most accurate antenna array can signal suppression and strengthen the specified direction at the same time,multi-input multi-output(MIMO)system to LoS-common optimal antenna array geometry configuration mode to make theoretical derivation,the antenna array weighted algorithm and the geometric design affects the performance of the system are analyzed in the simulation,Verify the LoS-MIMO system relative to the single input single output performance gain of the SISO system,at the same time proved that the optimal design method and antenna array antenna separation product ASP weighted alignment method to LoS-the importance of MIMO,and put forward the frequency selective fading antenna array under the joint optimization method,further enhance the frequency selective fading under the millimeter wave LoS-channel capacity of MIMO communication system.Finally,an equalization scheme is proposed to further optimize the performance of millimeter-wave LoS-MIMO communication system under frequency selective fading.This paper introduces the general situation of equalization technology,secondly introduces the traditional 2 × 2 LoS-MIMO equalization algorithm communication system includes: time domain equalization algorithm and orthogonal frequency division multiplexing OFDM system under frequency domain equalization FDE algorithm,proposed in view of the 2 × 2 LoS-SC MIMO communication system the single carrier frequency domain equalization algorithm: one is based on frequency domain equalization of TS training sequences,another uses a frequency domain equalization algorithm based on reduced training sequence of STS.Finally,under the frequency selective fading channel,the different equilibrium method for 2 × 2 LoS-MIMO communication system has carried on the system simulation,found multi-input multi-output system can be based on SC-FDE LoS-with less overhead and lower calculation cost,effectively reduce intersymbol and flow,the interference between resistance to frequency selective fading,at this point,FDE method seems more promising than the traditional TDE method;And SC-FDE and OFDM has approximate balance of performance,SC-FDE because of its constant envelope advantages relative to OFDM system for rf linear demand is low,low sensitivity to the carrier frequency offset CFO,and SC-FDE has a smaller than OFDM overhead,again due to similarity of system structure,both in some scenarios and OFDM system can form a pair of complementary advantages of flexible choice.