| Summary: | 碩士 === 國立交通大學 === 電信工程研究所 === 104 === In IEEE 802.11, when a device attempts to transmit information on the wireless channel, it first detects the channel condition based on CSMA/CA in order to avoid collisions. RTS/CTS mechanisms have been introduced to solve the collision issues. However, whether the receiver successfully receives a packet depends on SINR requirement at the receiver. By using physical carrier sense, some transmitting attempts around the receiver can be reduced, but corresponding hidden and exposed terminal problems occur. In order to reduce collisions at the receiver, we have to take transmitting rate, the distance between transmission pair and interference into consideration. In RTS/CTS mechanisms, by combining physical carrier sense with virtual carrier sense, it is possible that more severe exposed terminal problem will take place. Therefore, in order to reduce the interference level and collision at receiver, we have to consider the environment at the receiver. In this thesis, we propose a Rate-aware Power Control (RPC) algorithm with busy tone support to reduce interference and collisions in carrier-sensing wireless networks. By utilizing busy tone, the receiver informs the neighboring nodes of its SINR requirement, and then the transmitting nodes determine a suitable transmitting power and rate. In this way, other receiving nodes will be able to tolerate this interference within the SINR requirement. The goal of RPC is to maximize the network throughput and reduce the interference at receiver. We use network simulator ns-2 to evaluate the performance of RPC and compare with related mechanisms. Simulation results demonstrate that our RPC protocol improves the system throughput significantly.
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