The Research On Radio Resource Scheduling Algorithms In TD-LTE System

Current ly, mobile communication has developed to the fourth generation. Inthe first generation mobile communication system, it is entirely voice businessoriented, but in the subsequent development, the effective support of data servicesaccounts for a growing role. This trend begins in the Third Generation PartnershipProject (3GPP) organization, especially as the mobile communication technologydevelops to the third generation. At the same time, in order to confront thechallenges of the mobile communication technology, such as the WiMAX(Worldwide interoperability for Microwave Access) technology, the3GPP LTE(Long Term Evolution) project, through continuous research of manycommunication investigators, LTE has become a widely used standard and theresearch products are industrialization and marketization gradually.Scheduling algorithm, as one of the key technologies of LTE, is widelyconcerned by researchers and engineers. The LTE system on the shared resourcescheduling algorithm is equivalent to the traditional cellular networks on channelallocation algorithm. How to flexibly allocate and dynamically adjust the availablewireless network resources, under the premise of ensuring the network QoS(Quality of Service), maximizing the spectrum utilization and system capacity, agood scheduling algorithm has played a key role in determining systemperformance. The pre-research of the correlated algorithm is an integral part forLTE.This paper first introduces the project background, the significance of theproject. After, the status of LTE system and LTE scheduling algorithms is brieflyintroduced. The introduction of the following chapters mainly aims to TDD (TimeDivision Duplex) mode of LTE system.In the second chapter, the paper introduces the MAC (Media Access Control)layer scheduling principle, analyses the signaling, its role and the transmissionpattern related to the MAC layer scheduling. At last, it states the MAC schedulingprocess, mainly the default mode for TD-LTE systems, dynamic scheduling, whichlays the foundation for later understanding of the TD-LTE scheduling algorithmoverall.In the third chapter, two scheduling modes of LTE system are introduced,dynamic scheduling mode and semi-persistent scheduling mode, and then theusage scenarios of two scheduling modes are analysed. Dynamic scheduling modehas been introduced in detail in the second chapter. This chapter introducessemi-persistent scheduling mode. After, three classic scheduling algorithms are introduced to deepen the understanding of the scheduling algorithm, and as acomparison of LTE scheduling algorithm proposed later in this article.Chapter IV first expounds the proposed dynamic scheduling algorithm, thenanalyses of the flowchart of scheduling algorithm, due to the difference of theuplink and downlink in LTE system, they are discussed respectively. Finally, thealgorithm is simulated and analyzed to prove that the algorithm can satisfy theneeds of the actual system.Chapter V conducts a simulation analysis on semi-persistent schedulingalgorithm. First, semi-persistent scheduling applies, i.e. the VoIP (Voice over IP)service is introduced. After, it gives an introduction of semi-persistent schedulingalgorithms and process, analyzes the key technology of the semi-persistentscheduling, such as speech source coding and adaptive modulation scheme. Thechapter concludes with semi-persistent scheduling algorithm simulations, andanalysis the influences of the several key technologies for VoIP services.Finally, this article summarizes and gives the paper conclusions.