The Research Of Cell Users' Classification Algorithm Based On SFR In LTE System

With the continuous improvement of 4G technology,LTE enters into large-scale commercialization stage,although the problem of interference within the cells has been solved by using OFDM technology,LTE's same frequency network scheme also causes a serious inter-cell interference.In order to solve this problem,3GPP has established several kinds of interference suppression schemes,it mainly includes interference randomization,interference cancellation and interference coordination.Interference coordination becomes the mainstream of interference suppression because of its low cost and high practicality.Of course,interference coordination also has shortcomings,especially the user classification algorithms will seriously affect its performance,so the article proposes a new user classification algorithm in order to improve the interference coordination technology and mitigate inter-cell interference.First of all,the paper introduces the LTE's network structure and air interface,then it analyzes the principle of OFDM and MIMO,the two technologies are the core of LTE,they also determines the anti-interference capability of the LTE.The OFDM technology can effectively improve the system's bandwidth utilization,and reduce the multipath effect,the MIMO technology can obviously improve the system's throughput and reliability.This paper also introduces several methods of interference suppression,which including SFR scheme and FFR scheme.The paper will be based on SFR to study improved algorithm,because it is excellent and it has both flexibility and practicability.In order to test the performance of improved algorithm,this paper builds the LTE system level simulation platform based on SFR technology.The platform is built in two steps,first of all,it needs to determine the simulation flow and basic parameters according to the LTE protocol specification;and then,it needs to build simulation from base station,user,noise model,business model,shadow fading and other aspects.The paper also lists the performance evaluation parameters of LTE,it mainly includes SINR and throughput.After simulation platform is completed,the paper examines SFR technology when the number of users changes,and the data obtained here can be compared with later simulation results.The focus of this article is to study user classification algorithm of SFR,therefore,the paper briefly explains several user classification algorithms and analyzes their shortcomings in detail.The original user classification algorithm generally uses a fixed threshold to classify users,this classification is simple,but not accurate enough,in order to solve the shortcoming,this paper proposes a new user classification algorithm which takes into account both distance and SINR.The improved algorithm can accurately find the middle distance users who are seriously affected by interference,and make a more reasonable division of them.In this paper,the new algorithm is verified by simulation experiments,experimental results show that the new algorithm can effectively use bandwidth and increase edge users' throughput.So the paper finally concluded that the improved algorithm is better than the original algorithm.