Research And Implementation Of LTE Downlink Resource Scheduling Algorithm Based On CQI Mapping

With the development of the mobile communication technology and the advent of the mobile Internet era,the mobile communication business has been developed from the simply voice of business to multimedia service types combined with the internet,how to use the bandwidth resource efficiently must be paid more attention for the designers of the wireless communication system and the communication system's efficiency largely depends on the resource scheduling and allocation algorithm.Considering that wireless technology has a rapid growing and the new multimedia services has a severe demand on the communication system,this paper studies and implements the downlink resource scheduling algorithm of LTE system.In terms of sub-band CQI distribution,we usually use the EESM method to map the CQI and the current scheduling algorithm usually distributes RB first and then maps the CQI in serial process.This paper first conducts the research about the CQI mapping,and for the shortcomings of high complexity and the mapped CQI may not match the actual environment for EESM,this paper implements an improved linear method of HM which is based on the original linear HM algorithm,this method will adjust the mapped CQI to match the actual environment according to the characteristics of wireless environment.On this basis,a downlink resource schedule algorithm which combines the RB distribution with the CQI equivalent is proposed.When the base station distributes RB for the user,the loss of the CQI equivalent will be considered at the same time,through the rational allocation of resources,the resource utilization is improved,moreover,this scheduling algorithm considers the fairness of the users as well.Finally,we realize the idea by using heuristic algorithm of ant colony algorithm.Specific research contents and results are as follows:1.Analysis the HM algorithm performance in theory,and in view of the CQI estimation error and the rapid change of the wireless environment,we fine-tune the CQI after it is equivalent based on the ACK from the user,then design and implement the CQI mapping algorithm based on the actual LTE platform of our laboratory,though user equipment access,the effectiveness of the HM algorithm and the performance of the improved HM algorithm are verified;2.The dissertation establishes the mathematical model of user fairness and throughput index in LTE downlink resource allocation,and we build an optimization problem to maximize the throughput and consider the fairness as well by the restrict between formula,then on this basis,we propose the idea of combining allocation with CQI mapping in the process of the downlink resource scheduling;3.Compare the proposed algorithm with the existing algorithm for maximum throughput and round robin algorithm in system throughput,user fairness,and the spectrum utilization index in theory,and finally,we apply the improved HM CQI mapping method to the proposed scheduling algorithm and verified the superiority of the proposed algorithm in fairness and throughput index based on LTE platform in our laboratory.