Improvement of Throughput and Analysis of the Delay Time for 802.11 Ad-hoc Network

• Main Authors: Tsung-Han Lin, 林宗翰
• Other Authors: Pau-Lo Hsu
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/62958642733146629107

碩士 === 國立交通大學 === 電機與控制工程系所 === 94 === In this thesis, a new method called the channel allocation procedure (CAP) is proposed and its physical protocol of IEEE802.11 ad-hoc network is further modified to sequentially apply the hopping procedure based on the single-channel communication. By combining both the proposed CAP method and the ad-hoc on-demand distance vector routing (AODV), an effective communication interface for the multi-agent traffic control system is thus established. By applying the CAP method, the hidden terminal problem which is the main cause of the degradation of network throughput is solved. By evaluating the CAP method using the NCTUns network simulator, results revealed that the throughput of the proposed CAP method increases by 75% to 2300% compared with the original 802.11 ad-hoc networks. Furthermore, since the value of the delay time caused by the wireless communication is required in the design procedures of the Smith predictor in the network control system (NCS), the average delay time of the ad-hoc network between the two application layers of the server and the client is measured and analyzed to suppress the delay effect. It is found that various transmit rates and payload sizes mainly affect the delay time. Experimental results further indicate that the delay time is independent of the transmission distance and it increases when the payload size increases. Moreover, applying the higher transmit rate leads to the lower time delay in NCS.