The Research Of Lte Resource Scheduling Algorithms And Implementation Of Scheduling Module In LTE Simulation Platform

With the presence of mobile Internet, user demands for higher throughput and better quality of service (QoS) of mobile communication have increased rapidly and traditional2G/3G mobile cellular network can hardly meet this kind of needs. To face these ever growing demands,3rd Generation Partnership Project (3GPP) introduces the Long Term Evolution (LTE) as the next generation of mobile cellular network standards. LTE introduces the Orthogonal Frequency Division Multiplexing (OFDM) as multi-access transmission mode. It will decrease the interferences dramatically while improving system throughput.In LTE system, channel is divided into many orthogonal carriers. Considering characteristics of Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) in LTE uplink, more limits are introduced and resource scheduling problem becomes more complex. In addition, since packet delay infonnation is not provided by LTE control message, Users’ QoS requirements can hardly be met in recent research.This paper will research uplink resource scheduling on basis of predecessors’work. Consider characteristic of uplink transmission, the object is to guarantee QoS of users and improve overall system throughput. The key work is as following:Fistly, based on the3GPP standards, the multiplexing access technology and resource scheduling scheme are depicted in detail. The characteristics and problems related to resource scheduling are summarized here. At the same time, this paper has surveyed current LTE scheduling algorithms, summarized and classified their designs. The comparison of performance is also included.Since the packet delay information cannot be obtained by scheduler directly, this paper proposes a kind of packet delay estimation algorithm which will make full use of buffer status report (BSR) arrival time information. Then, relay node is included in the system, and a relay node selection tragedy is proposed. Condition of wireless channel will enhance greatly. Based on the thought of cooperation, this paper considers the constraint of SC-FDMA and introduces a creative resource allocation algorithm here. Alternative resource sets are introduced to make resource reallocation possible. Channel condition, buffer size and packet delay are all considered in the scheme. As a result, the system throughput and delay performance can be improved greatly, and then guaranteed users’ QoS requirements.Furthermore, this paper implements the LTE resource scheduling module of network simulator3(NS-3) as the3GPP protocol standards. In simulation platform, the scheduling signaling and configuration signaling are designed and realized, which can simulate the whole procedures of resource scheduling. By use of polymorphism in C++, this paper constructs abstract class of scheduler and provides interfaces to other modules. All functions related to scheduling are declared. The design can improve the system extension while guarantee system reliability. Several classic schedulers are implemented, which will provide great convenience to following research.