| Summary: | 碩士 === 國立中山大學 === 資訊工程學系研究所 === 103 === The 3GPP organization continues developing long term evolution (LTE) to support the oncoming 4G cellular communication. In LTE, flow scheduling plays an important role in system performance, and flows are mainly categorized into guaranteed bit rate (GBR) and non-GBR classes depending on their service types. Although various flow scheduling schemes have been proposed, many of them do not differentiate GBR flows from non-GBR ones, which may not support quality of service (QoS) for GBR flows. Therefore, the paper designs a service-differentiated downlink flow scheduling (S-DFS) algorithm, whose objectives are to meet the QoS requirement of GBR flows, while guarantee the transmission of non-GBR flows. S-DFS starts by dealing out resource to user equipments based on their channel conditions, and prioritizes flows according to QoS class identifier (QCI) defined in LTE. Then, S-DFS calculates a dynamic amount of reallocatable resource, and adaptively gives such resource to those flows whose packets are about to be dropped. Experimental results demonstrate that S-DFS can improve the overall transmission efficiency of an LTE network. In addition, it can reduce both the dropping ratio and the average delay of GBR packets, while increases the data throughput of non-GBR flows.
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