An Efficient MAC Protocol with SINR-based Space Overlap
| Autor: | Chih-Chen Kuo, 郭志成 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 IEEE 802.11 DCF (Distributed Coordination Function) standard is widely used to solve the hidden terminal problem in the wireless environment. The four-way handshake mechanism of DCF is used to occupy the channel grant, to avoid interference with other nodes that may influence on the ongoing communication. The communication pairs that have contended channel grant broadcast control frames (RTS or CTS) to inform their neighboring nodes of what the ongoing communication will create soon. The neighboring nodes set NAV (Network Allocation Vector) state by themselves according to the received control frames. During NAV state, the neighboring nodes could not transmit any signal for interference avoidance. Although DCF mechanism can effectively resolve the hidden terminal problem, but the neighboring nodes under NAV state are not allowed to communicate with the other nodes. As we mentioned, the phenomenon limits the number of communication pairs, which lead the improvement in network throughput to restraint. In addition, control and data frames using different transmission rate have different transmission range and SINR threshold in the multi-rate environment. The transmission range of control frames is larger than data frames’ because the lower transmission rate, which results in that the improvement in the number of communication pairs is limited more seriously. In this paper, we analysis the status of signal interference between the communication pair and neighboring nodes, and discuss the relation to nodes'' location and nodes'' role. According to the previous analytic results, we design an efficient MAC protocol with SINR-based space overlap, which determines whether the neighboring nodes can communicate with another node or not. Our proposed protocol can evaluate the status of signal interference among neighboring nodes by the corresponding received signal strength. Our proposed protocol uses the characteristic of space overlap for allowing the neighboring nodes to communicate with another node simultaneously, and it also avoids signal collision by inhibiting interference. The transmission rate of signal is suitably adjusted to corresponding channel condition in our proposed protocol, which not only increases the number of communication pairs, but also improves the network throughput. In the simulation result, our proposed protocol has more communication pairs simultaneously than ARF protocol. In addition, our proposed protocol also shows better packet delivery ratio, transmission delay, and throughput than ARF protocol. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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