Research On Packet Scheduling Algorithms In HSDPA System

Packet scheduling technique is the fundamental technology to wireless packetdata transmission. It controls the allocation of shared resources, and determined theperformance of the packet data transmission, affected the capacity and efficiency ofthe whole system. High speed downlink packet access (HSDPA) system introduceshigh speed shared channel, which needs the packet scheduling technique having betterperformance and greater flexibility to maintain and improve the advantage of HSDPAtechnology. So in this thesis, packet scheduling technique for HSDPA systems isstudied for current packet scheduling algorithms are applied in HSDPA, the mainachievements are outlined as follows:Firstly, the elements of packet scheduling algorithms are analyzed for generalwireless communication systems. Studied and simulated the classic packet schedulingalgorithms of HSDPA systems for different types of business. And their performancesare compared, such as the throughput of system, the called packet time delay and thefairness of users.Secondly, the packet scheduling algorithm which can ensure the quality of service(QoS) of different business for supporting the real-time business and the non-real-timebusiness at the same time is studied. The improved packet scheduling algorithm basedon the proportional fairness (PF) algorithm and the modified largest weighted delayfirst (M-LWDF) algorithm, with the time delay weighted element is introduced toschedule the arrived packet data. And the performance of the improved packetscheduling algorithm from the throughput of system and the fairness of userssimulation is analyzed.Thirdly, the packet scheduling algorithm which could support the streamingservice is studied. The improved packet scheduling algorithm could still support thereal-time business and the non-real-time business at the same time. The improvedpacket scheduling algorithm combines the proportional fairness (PF) algorithm and themodified largest weighted delay first (M-LWDF) algorithm, with the throughput threshold is introduced to schedule the arrived packet data. And the performance of theimproved packet scheduling algorithm is analyzed from the simulation of the systemthroughput and the users’fairness.