| Beam management is an important technical means in millimeter wave communication.Due to the large propagation loss and attenuation in millimeter-wave systems,stable beam alignment is required to ensure communication quality.The means of auxiliary beam alignment include out-of-band information assistance,radar assistance,position information and angle information assistance,motion trajectory estimation,and the like.This paper focuses on the scheme design and beam design of beam selection and beam tracking.The main research contents include:(1)Beam selection scheme based on LWOMP algorithm is improved.Compared with the OMP sparse recovery algorithm,the LWOMP algorithm introduces a weighting factor to adjust the iterative results.In this paper,the weighting factor is improved,the spatial information of the low-band channel is introduced as the a priori information of the millimeter-wave channel in the weighting factor,and the line-of-sight path energy ratio is proposed as an auxiliary variable to improve the weighting factor auxiliary effect to the weighting factor.The credibility of the adjustment is adjusted.In this paper,the sparse characteristics of the dual-band channel are simulated and theoretically analyzed,and the performances of the two schemes are compared.The improved scheme has higher spectral efficiency results under the same training cost.It can also be obtained from the simulation that the effective reachable rate and success ratio of the LWOMP scheme are significantly improved compared with the OMP scheme.(2)A beam tracking algorithm based on position estimation is proposed.The traditional algorithm reduces overhead by two levels of iteration,and performs fast beam training to achieve beam tracking.The proposed algorithm utilizes the characteristics of the user's slow movement and the characteristics of the rough angle estimation during the scanning process.The scanning range is determined by obtaining the angle estimation deviation,thereby minimizing the second-level iteration overhead,reducing redundancy and improving switching efficiency..In this paper,the model is used to derive the estimated lower deviation of the launch angle,the acceptance angle,the steering angle and the user position,and the Fisher information matrix is introduced as a reflection of the estimation effect.We will compare the performance of the proposed algorithm with the traditional RSRP tracking algorithm.It can be seen that the normalized SNR is significantly improved and the total overhead is reduced.In this chapter,it can also be found that the long-distance and the estimation behind the scatterer are poor,resulting in a significant increase in overhead.Therefore,the algorithm requires more densely distributed small base stations to ensure better performance.(3)Two beam design schemes for V2 I beam switching was compared and analysed.In the link budget model,we analyze the beam overlap scene in the straight road V2 I and obtain the expressions of the interruption time and data rate.The performance comparison and analysis of the schemes with equal beam projection coverage and the equal beamwidth are performed.It can be found that the equal coverage design results in a higher data rate while ensuring the same outage rate.However,compared with the equal beam width design,it is greatly affected by the speed estimation error,so it will be strongly affected when the estimation result becomes worse. |
PDF Full Text Request