70 research outputs found
Cognitive Location based Mobile Adhoc Networks Implementation with an Android Operating Systems
Cognitive radio (CR) technology is envisaged to solve the problems in wireless networks resulting from the limited available spectrum and the inefficiency in the spectrum usage by exploiting the existing wireless spectrum opportunistically. CR networks, equipped with the intrinsic capacities of the cognitive radio, will provide an ultimate spectrumaware communication paradigm in wireless communications. Specifically, in cognitive radio ad hoc networks (CRAHNs), the distributed multihop architecture, the dynamic network topology, and the time and location varying spectrum availability are some of the key distinguishing factors. In this paper, intrinsic properties and current research challenges of the CRAHNs are presented. A particular emphasis is given to distributed coordination between CR users through the establishment of a common control channel. Lastly, a new commission called the park model is explained, where CRAHN users may independently determine their own performance based on pre-decided spectrum. The performance is comparable to MANET routing protocols In this system implementation through real time systems with Specialized ANDROID BASED OPERATING SYSTEMS
An Efficient Cluster-based Routing Protocol in Cognitive Radio Net-work
Cognitive Radio Networks (CRNs) are being studied intensively and gaining
importance as spectrum is the heavily underutilized. CRN has the capability to
exploit smartly the unutilized frequency spectrum. Recently, the research
community started to work in the area of cognitive radio routing. In a flat
topology, all nodes are of the same level and functionality, thus making it
simple and efficient for smaller networks. However, when the network is large
with sparse nodes, the routing information becomes more complex making
cluster-based techniques really relevant to tackle such situations. In a
cluster-based routing, all nodes in the network are dynamically organized into
partitions called groups or clusters. In each cluster, a cluster head is chosen
to help in the data transmission management and to maintain cluster membership
information. This paper proposes a novel routing protocol for cognitive radio
ad hoc networks (CRAHNs) based on clustering model which amends swiftly to the
topological changes and establishes the routing efficiently. Our proposed
approach is thoroughly evaluated through simulation study. The results state
the suitability of the proposed protocol for cognitive radio ad hoc networks
and demonstrate that it has better performance in terms of finding the
source-destination route, reducing the amount of messages that are transmitted
all over the network and minimizing the routing delay.Comment: International Conference on Advanced Communication Systems and Signal
Processing (ICOSIP 2015), Nov 2015, TLEMCEN, Algeria. 201
SMART: A SpectruM-Aware clusteR-based rouTing scheme for distributed cognitive radio networks
Cognitive radio (CR) is the next-generation wireless communication system that allows unlicensed users (or secondary users, SUs) to exploit the underutilized spectrum (or white spaces) in licensed spectrum while minimizing interference to licensed users (or primary users, PUs). This article proposes a SpectruM-Aware clusteR-based rouTing (SMART) scheme that enables SUs to form clusters in a cognitive radio network (CRN) and enables each SU source node to search for a route to its destination node on the clustered network. An intrinsic characteristic of CRNs is the dynamicity of operating environment in which network conditions (i.e., PUsâ activities) change as time goes by. Based on the network conditions, SMART enables SUs to adjust the number of common channels in a cluster through cluster merging and splitting, and searches for a route on the clustered network using an artificial intelligence approach called reinforcement learning. Simulation results show that SMART selects stable routes and significantly reduces interference to PUs, as well as routing overhead in terms of route discovery frequency, without significant degradation of throughput and end-to-end delay
DISTRIBUTED INTELLIGENT SPECTRUM MANAGEMENT IN COGNITIVE RADIO AD HOC NETWORKS
The rapid growth of the number of wireless devices has brought an exponential increase in the demand of the radio spectrum. However, according to the Federal Communications Commission (FCC), almost all the radio spectrum for wireless com- munications has already been allocated. In addition, according to FCC, up to 85% of the allocated spectrum is underutilized due to the current fixed spectrum alloca- tion policy. To alleviate the spectrum scarcity problem, FCC has suggested a new paradigm for dynamically accessing the allocated spectrum. Cognitive radio (CR) technology has emerged as a promising solution to realize dynamic spectrum access (DSA). With the capability of sensing the frequency bands in a time and location- varying spectrum environment and adjusting the operating parameters based on the sensing outcome, CR technology allows an unlicensed user to exploit the licensed channels which are not used by licensed users in an opportunistic manner.
In this dissertation, distributed intelligent spectrum management in CR ad hoc networks is explored. In particular, four spectrum management issues in CR ad hoc networks are investigated: 1) distributed broadcasting in CR ad hoc networks; 2) distributed optimal HELLO message exchange in CR ad hoc networks; 3) distributed protocol to defend a particular network security attack in CR ad hoc networks; and 4) distributed spectrum handoff protocol in CR ad hoc networks. The research in this dissertation has fundamental impact on CR ad hoc network establishment, net- work functionality, network security, and network performance. In addition, many of the unique challenges of distributed intelligent spectrum management in CR ad hoc networks are addressed for the first time in this dissertation. These challenges are extremely difficult to solve due to the dynamic spectrum environment and they have significant effects on network functionality and performance. This dissertation
is essential for establishing a CR ad hoc network and realizing networking protocols for seamless communications in CR ad hoc networks. Furthermore, this dissertation provides critical theoretical insights for future designs in CR ad hoc networks
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