4295

4066

كارشناسي ارشد

مخابرات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1386

نه، 136، [II] ص.: مصور، جدول، نمودار

ص.ع. به: فارسي و انگليسي

مهندسي برق و كامپيوتر

ID4066

به فارسي و انگليسي: قابل رؤيت در نسخه ديجيتال

Abstract In this thesis we propose and analyze a new wireless MAC protocol based on anovel approach In this approach two control tones called request pulse and receiverbusy tone are employed to coordinate the use of the wireless medium and to preventpotential collisions Each tone is sent using a dedicated frequency channel other than thechannel used for data transmission The request pulse is a very short pulse sent by atransmitter before it sends data on the data channel in order to alert neighboring nodesabout its forthcoming data transmission The receiver busy tone is sent by the receiverwhile it successfully receives data and is continued for a short while after data receptionhas been completed We demonstrate that the proposed scheme is effective in efficientlycoping with typical LAN problems such as the hidden node and the exposed nodescenarios As a further enhancement to the scheme we have come up with another novelidea we adopt multiple distinguishable pulse shapes to be used as request pulse bydifferent nodes thereby further reducing the probability of collision between data packetsand increasing the achievable LAN throughput Using analysis we study the performanceof our protocol under some typical scenarios and determine the relationship betweencollision probability delay and throughput with network load and propagation time Weshow that the proposed scheme overcomes some of the deficiencies of the current wirelessLAN protocols

جمال الدين گلستاني

علي محمد دوست حسيني