| Summary: | 博士 === 中興大學 === 資訊科學與工程學系所 === 99 === The IEEE 802.16 family is a candidate fourth-generation mobile communication standard that provides ubiquity, high transmission rate, quality of service (QoS), and low-cost services. Among the 802.16 family, 802.16e specifies QoS support at the MAC level, while 802.16j spreads out the coverage of Worldwide Interoperability for Microwave Access (WiMAX) networks and strengthens wireless signal transmission using relay technology. Thus, 802.16j is chosen in the metropolitan environment and 802.16e is preferred in sparsely populated territories in order to deploy 802.16 services efficiently. Consequently, 802.16e/802.16j coexistence environment is beginning to take shape. The deployment of WiMAX networks would be flexible, if the base station supports both 802.16e and 802.16j technologies. In this paper, a novel scheduling mechanism is presented for high transmission rate and QoS in 802.16e/16j coexistence networks.
The adoption of OFDMA and relay techniques in 802.16e/802.16j networks, although adding complexity, increases flexibility over the original 802.16 networks. This may permit parallel transmission among multiple devices. However, little current research has addressed the issue of parallel transmission in a scheduling algorithm. And, the interference profile among multiple devices is assumed to be already known before transmission commencement. In this paper, an efficient uplink scheduling mechanism, Parallel Transmission with Low Maximum Latency Violation (PT-MLV), which allows parallel transmission, is proposed. Using PT-MLV, uplink resource utilization can be improved and the requirement of real-time applications can be better satisfied due to the MCS and low maximum latency violation. In addition, we first present an interference detection mechanism for parallel transmission. Our experimental results demonstrate that PT-MLV scheduling outperforms regular relay scheduling in average transmission rate and maximum latency violation.
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