| Summary: | 碩士 === 淡江大學 === 電機工程學系 === 91 === Recent years have witnessed a tremendous growth of research and development to provide mobile users with reliable and convenient communication through wireless media. This thesis deals with the improvement of the medium access protocol for mobile ad hoc networks. While most wireless MAC (medium access control) protocols have the ability to split oversized LLC (logic link control) data into multiple transmissions, none has the ability to send multiple LLC data frames within one physical layer frame. To add the missing functionality, we propose a mechanism that sends out multiple MAC layer packets within a single physical layer frame - packet flushing transfer mode (PFTM). PFTM is an enhancement of the IEEE 802.11 MAC DCF (distributed coordination function). However, the basic concept of PFTM can also be used by other MAC protocols similar to the 802.11 MAC. The major innovation introduced by PFTM is the compilation process (CP), which compiles multiple MSDU (MAC service data unit) packets into a single cMPDU (compiled MAC protocol data unit) packet. To the physical layer MPDUs and cMPDUs are identical, and a cMPDU is literally a series of coupled together MPDUs. Since PFTM uses extended frame formats and thereby is not compatible with the IEEE 802.11 standard, an "802.11 compatible mode" based on the same basic concept as PFTM (sacrificing performance) is also provided. By using PFTM, we lower the percentage of overhead for the protocol to send data and lessen network contention. Simulation results backed by numerical analysis show promising results for the PFTM.
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