Research On Resource Scheduling Algorithm And Component Carrier Management For Carrier Aggregation Int LTE-advanced System

To meet the the demand of mobile users for broadband services,3GPP carried out the evolutionof3G systems, named LTE (Long Term Evolution).With the rapid development of LTEsystems,3GPP gradually began to research the LTE-Advanced (LTE-A) system, and focuses oncarrier aggregation (CA) to resolve the problem of bandwide expansion and the requirement ofhigher transmission rate, and to ensure backward compatibility.The introduction of CA has brought a series of new problem to resource assignment in LTE-Asystem, such as carrier load balancing. LTE-A system is compatible with LTE,that is two kinds ofusers coexistent in LTE-A system, which may make some influence to the performance of thesystem in resolving the problem of system resource scheduling.In this thesis,we focus on the resource scheduling of Long Term Evolution-Advanced (LTE-A)with Carrier Aggregation (CA). Application of CA meets the demand of bandwidth in LTE-A byaggregating several discrete carriers together. With different fading characters, the aggregatedcarriers have different coverage between each other. Considering the backward compatibility, thereexists both LTE-A and LTE users. In order to improve the performance of LTE users and cell edgeusers, an improved proportional fair (PF) scheduling algorithm suitble to multi-carrier system isproposed. In this algorithm, a variable to limit the number of carriers each user can access is set,and a carrier weight factor which is composed of carrier coverage weight factor and user categoryweight factor is introduced. Simulation results show that the proposed algorithm can effectivelyimprove the performance of cell edge users and LTE users.However, in certain circumstances, aggregating entire available carriers for a UE is notmeaningful due to probably low channel quality or high traffic load in some of the CCs. Therefore,how to make good use of multiple carriers in real deployment scenarios is an important issue.Basedon the analysis of resource allocation across multiple carriers in Layer-2, two CC managementmethods in Layer-3are proposed. The proposed method is shown by simulation results to beeffective in providing comparable user throughput with lower implementation complexity, ascompared to solely ingenious resource allocation.