Research On Comparison Of Channel Characteristics At Low And High Frequency Band

In order to meet the rapid growth of mobile data transmission require-ments of today's mobile Internet and the future of the Internet of Things,the fifth generation of mobile communication systems(5G)will soon be put into commercial use in 2020.Due to the excellent transmission characteristics of the low frequency band below 6 GHz,a large number of commercial services have allocated more low-band spectrum resources,and low-band resources are scarce.Thus the candidate band has been extended to the high band up to 100 GHz in the 5G channel model.In order to deeply study the relationship be-tween the propagation characteristics of the low frequency band below 6 GHz and the high frequency band above 6 GHz on the Multiple Input Multiple Output(MIMO)channel and the channel characteristics of the indoor shopping mall in the important scenes of the 5G system,this paper is based on the current The multi-band channel measurement platform designs and implements the indoor and low-channel channel comparison indoor scene measurement scheme,and analyzes and compares the channel parameters of the high and low frequency bands in the scene.The specific resear-ch work of this paper includes:Propose a new channel denoising method:In the preprocessing of channel measurement data,the conventional channel denoising method has poor gen-eralization and excessive manual intervention.A new perspective on channel denoising is explored.Finally,a gradient-based denoising method is proposed,which has good universality in denoising processing.Computing optimization of channel parameter estimation algorithm:In the processing of extracting and calculating channel parameters,the calculations of all the parameters of the whole scene with the channel parameter estima-tion algorithm SAGE under the current single machine are too time consuming,this paper optimizes the algorithm into a parallel distributed computing method based on MPI,and deploys it to the distributed cluster,which Significantly im-prove overall task computing efficiency.Comparison on channel characteristics of indoor shopping mall scenes:Based on the latest 5G system candidate bands and existing measurement equip-ment,this paper selects 3.5 GHz and 28 GHz as the representative frequency points of high and low frequency bands.At the same time,the virtual MIMO measurement scheme in the 28 GHz band was designed for the case where the hardware limitation of the measurement equipment in the 28 GHz band could not be measured by MIMO channel.And the indoor shopping mall scene was selected to complete the comparison measurement of single antenna and MIMO in the 3.5 GHz and 28 GHz bands.At the same time,based on the new denois-ing method and the optimized distributed parameter estimation algorithm,the channel parameters are extracted and calculated.Finally,the propagation char-acteristics of the extracted channel parameters,including the delay parameters and the angle parameters,are divided into different propagation characteristics in the high and low frequency bands.In summary,this paper designs and implements channel characteristics comparison measurement in the indoor shopping mall scenario for the candi-date bands of 3.5 GHz and 28 GHz in the 5G system to be commercialized.Then,the channel data is extracted and calculated by exploring a new denois-ing method and optimizing the SAGE parameter estimation algorithm.Finally,based on the extracted parameters,the parameters such as path loss,time delay and angle of the channel at high and low frequencies are analyzed in depth.