Carrier Aggregation based Downlink Packet Scheduling Scheme with Improved Quality of Service

Abstract

To achieve the capacity of present cellular network with fast growing data demand in the International Telecommunication Union has defined the specification of 4G systems.4g systems support high system capacity.They are also called as International Mobile Telecommunications-Advanced (IMT-A) cellular systems Based on the economic and service demands IMT-A systems must provide their support to the data rates.In the 3rd Generation Partnership Project (3GPP), it is agreed that Long Term Evolution-Advanced (LTE-A) systems, the evolution version of LTE systems, should meet the requirement of IMT-A systems.The progress of key technologies in LTE-A and IMT-A systems can be referred in [1][2].LTE-Advanced should support wider bandwidth for high peak data rates and wide coverage.Carrier aggregation (CA),a technique that aggregates multiple adjacent component carriers into an overall wider bandwidth, is preferred for the spectrum compatibility.To Design an ideal packet scheduler in LTE-A system with CA the requirements to be satisfied are: 1) Requires to handle the packet scheduling in multiple CCs environments, 2) the required Quality-of-Service (QoS) needs to be supported for various kinds of traffics, 3) requires to achieve high system throughput, and 4) the fairness among users, traffic classes must be maintained.Many researchers have started to investigate the issues related to design of the scheduler for the LTE-A system with carrier aggregation, like L. Lei and K. Zheng analysed both the delay and the throughput performance in the LTE-A systems with carrier aggregation mechanism.L. Chenet al and K. Takeda et al. had proposed several CCs scheduling algorithms and scheduler structures in [3].To evaluate the performance of independent carriers in LTE-Advanced systems, several scheduling algorithms and scheduler structures are proposed.Performance results are compared with independent carrier(IC) mechanism, where CCs are not aggregated but used independently.The Purpose of this paper is to study the system level performance of CA in LTE-Advanced systems with and without considering service traffic class requirements.