An Opportunistic Cognitive MAC Protocol for Coexistence with WLAN
Date Issued
2007
Date
2007
Author(s)
Hung, Shao-Yi
DOI
en-US
Abstract
In last decades, the demand of wireless spectrum has increased rapidly with the development of mobile communication services. Recent studies recognize that traditional fixed spectrum assignment does not use spectrum efficiently. When licensees are not transmitting, spectrum remains idle. Such a wasting phenomenon could be amended after the present of cognitive radio. Cognitive radio is
a new type of technology that enables secondary usage to unlicensed user. Because its innovative idea overthrows the exclusive spectrum policy, cognitive radio requires a new open spectrum access protocol to transmit intelligently in fluctuant environment. This thesis presents a MAC protocol, namely Opportunistic Cognitive MAC Protocol (OC-MAC), for cognitive radios to access unoccupied resource opportunistically and coexist with wireless local area network (WLAN). By a primary traffic predication model and
transmission etiquette, OC-MAC avoids to producing fatal damage to licensed users. Then We examine and analyze the design of OC-MAC in the aspects bottleneck and fairness. Finally, a ns2 simulation model is developed to evaluate the performance of OC-MAC in scenarios with coexisting WLAN and cognitive network. The results indicate OC-MAC enhances network utilization from 8.74% to 37.49% and only results
in 0.52% collision to legacy users. The efficiency is almost nine times of our former work while with the same level of damage.
Subjects
感知型無線網路
網路媒體存取層協定
公用式網路存取
跨網路各層整合性設計
Cognitive Radio
MAC Protocol
Opportunistic Spectrum Sharing
Open Spectrum Access
Cross-layer design
Type
thesis