Dr. Ri7an

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Create time: 2009-07-27 08:52:34

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cognitive-mac-coexistence.rar - In last decades, the demand of wireless spectrum has increased rapidly with the development of mobile communication services. Recent studies recognize that traditional fi xed spectrum assignment does not use spectrum effi ciently. 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. This paper presents an Opportunistic Cognitive MAC Protocol (OC-MAC) for cognitive radios to access unoccupied resource opportunistically and coex- ist with wireless local area network (WLAN). By a primary traffi c predication model and transmission etiquette, OC-MAC avoids producing fatal damage to licensed users. Then a ns2 simulation model is developed to evaluate its performance in scenarios with coexisting WLAN and cognitive network.
WSN_OPNET.rar - Wireless Sensor Networks (WSNs) have attracted much attention in recent years. The potential applications of WSNs are immense. They are used for collecting, storing and sharing sensed data. WSNs have been used for various applica- tions including habitat monitoring, agriculture, nuclear reactor control, security and tactical surveillance. The WSN system developed in this paper is for use in precision agriculture applications, where real time data of climatologically and other environmental properties are sensed and control decisions are taken based on it to modify them. The architec- ture of a WSN system comprises of a set of sensor nodes and a base station that communicate with each other and gather local information to make global decisions about the physical environment. The sensor network is based on the IEEE 802.15.4 standard and two topologies for this application.
CR-OPNET.rar - In the last few years, there has been enormous improvement in mobile communication services. Due to this rapid growth in the field of communications, the demand for wireless spectrum has increased rapidly. In the early days in order to remove the interference problem, the spectrum was assigned statically. To assign the spectrum statically, the fixed spectrum assignment policy was used. Due to the fixed spectrum assignment policy, the spectrum was not efficiently utilized and remained vacant most of the time. The study by Federal Communications Commission (FCC) shows that the spectrum is available but its usage is not efficient. Such kind of spectrum inefficiency can be overcome by the use of Cognitive Radio.
Cooperative-Communications-and-Networking-2010.ra - cooperative communications
05752426.rar - Optimal Resource Allocation for MIMO Ad Hoc Cognitive Radio Networks
04797533.rar - Optimal Resource Allocation for MIMO Ad Hoc Cognitive Radio Networks

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