| Summary: | 碩士 === 國立中山大學 === 資訊工程學系研究所 === 103 === Due to the population of handheld devices, people are more depending on the wireless network. While wireless network is more important, 3GPP proposed a new wireless communication system ”Long Term Evolution” ,so called “4G-LTE”. LTE downlink data rate could be up to 1Gbps, and uplink data rate could be up to 500Mbps. The LTE has recently been investigating heterogeneous networks (HetNet) to deal with traffic demand.
In this paper, we focus on HetNets which consists of Macrocell and Picocells. Picocells use the Cell Range Expansion (CRE) technique to extend the Picocell coverage, so it can ease Macrocell traffic load. The CRE uses the biased to make user equipments (UE) offload to Picocell. However, there are some problems with CRE. First, if the biased is set a small value, the Picocell cannot cover more UEs to ease Macrocell traffic. Second, if the biased is set a large value, it may cover too more UEs such that Picocell cannot handle too many request. In this article, we present the mechanism that concerns the number of resources of the base stations and user conditions, and the mechanism will decide the UE’s biased.
In simulation results, it shows our mechanism can improve the average user goodput and total goodput、reduce the packet delay time and decrease the packet loss rate. According to the results, our mechanism adjusts the UE’s biased appropriately, and satisfy the QoS requirements of users.
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