| Summary: | 碩士 === 國立中興大學 === 資訊網路多媒體研究所 === 99 === IEEE 802.16j spreads out the coverage of WiMAX network and strengthens the wireless signal transmission using the relay technology. As the transmission could be taken place between Base Station and Subscriber Station or Relay Station as well as between Relay Station and Subscriber Station, a well-designed bandwidth scheduling mechanism allows synchronal transmissions among multiple devices. Most currently researches adopt the interference detect among devices before transmission to allow interference-free simultaneous transmission for bandwidth utilization improvement. Some of the researches were proposed for OFDM technique. However, the adopted technique of IEEE 802.16j is OFDMA. Besides, the frame structure of IEEE 802.16j is composed of access zone and relay zone, but these researches also didn’t taken it into account when the proposed scheme operates. So there is a compatibility problem in these researches.
By confirming to the standard specification of IEEE 802.16j, we propose an efficient uplink scheduling mechanism with enabling Multi-device Transmission and Maximum Latency Fulfillment(MT-MLF). With MT-MLF, an interference detection mechanism is first carried out, then a resource distribution algorithm and a dynamic frame adjustment method are developed. Using the MT-MLF mechanism, uplink resource utilization can be improved and the requirement of real time applications can be better satisfied. Two simulation experiments were carried out with different levels of interference degree. The results demonstrate that under a fixed QoS type of connections, when the total number of connections goes up to 420 and 360 and the maximum latency violation rate approaches 20%, the uplink average transmission rate of MT-MLF can achieve 7.92Mbps and 6.67Mbps, which apparently outperform on 3.91Mbps and 4Mbps as compared with regular relay scheduling scheme.
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