The Uplink Resource Scheduling Research In TD-LTE-A Carrier Aggregation System

The choice of OFDM-based multi-carrier access techniques for LTE marked a fundamental and farsighted parting from preceding 3GPP networks.With OFDMA in the downlink and SC-FDMA in the uplink,LTE possesses a robust and adaptive multiple access scheme that facilitates many physical layer enhancements.Despite this flexibility,scheduling in LTE is a challenging functionality to design,especially in the uplink.The purpose of this paper is to study carrier aggregation system of uplink resource scheduling.First of all,this paper presents comprehensive analysis of uplink resource scheduling in the carrier aggregation system.It is concluded that the LTE-A with the carrier aggregation technology makes the structure of uplink scheduling system a layer of extra CC level scheduling,which is no longer single the RB level scheduling,At the same time,because of limitation of the user terminal power problem,the existing scheduling algorithms for both CC and RB level do not perfect for the uplink scheduling.Secondly,this paper aims to design the modified CC level scheduling scheme based on the analysis of the existing three basic algorithm of CC level,which is not consider the disadvantages of the user channel.Modified CC level scheduling scheme combines path loss calculation and edge user group strategy to improve throughput edge users and to keep center user throughput constant.Due to the particularity of uplink access technology,the uplink LTE-Advanced system allocates the PUSCH resource in one or two consecutive blocks of resources as far as possible in order to reduce the peak-to-average ratio.On the analysis of scheme of cluster scheduling,this article adopts pre-allocation strategy to optimize the allocation of results in order to make up for discontinuous allocation algorithm in user throughput decrease brought by the power cut down.In this paper,based on pre-allocation of resource scheduling achieves uplink PUSCH discontinuous is the optimal allocation of resources under the premise that meet the needs of user data request.Finally combined with improved CC level scheme and multi-carrier uplink PUSCH allocation algorithm,forms the uplink resource allocation scheme in multiple carrier system.Finally,this paper carries on the simulation analysis and comparison respectively for CC level scheduling algorithm and RB algorithm.Through the simulation analysis of uplink resource allocation scheme,it is concluded that the improved CC scheduling algorithm based on edge-prioritized channel-and traffic-aware and RB scheduling algorithm based on pre-allocated discontinuous schedule scheme achieve the goal of uplink multicarrier optimal utilization of resources and enhance the network overall performance.