CROR: Coding-Aware Opportunistic Routing in Multi-Channel Cognitive Radio Networks

Cognitive radio (CR) is a promising technology to improve spectrum utilization. However, spectrum availability is uncertain which mainly depends on primary user's (PU's) behaviors. This makes it more difficult for most existing CR routing protocols to achieve high throughput in multi-channel cognitive radio networks (CRNs). Inter-session network coding and opportunistic routing can leverage the broadcast nature of the wireless channel to improve the performance for CRNs. In this paper we present a coding aware opportunistic routing protocol for multi-channel CRNs, cognitive radio opportunistic routing (CROR) protocol, which jointly considers the probability of successful spectrum utilization, packet loss rate, and coding opportunities. We evaluate and compare the proposed scheme against three other opportunistic routing protocols with multichannel. It is shown that the CROR, by integrating opportunistic routing with network coding, can obtain much better results, with respect to throughput, the probability of PU-SU packet collision and spectrum utilization efficiency.Comment: 6 pages, 8 figures, to appear in Proc. of IEEE GlobeCom 201

Review and Comparison of Routing Metrics in Cognitive Radio Networks

In this paper, cognitive radio network is briefly introduced as well as routing parameters in cognitive radio networks. Due to lack of Spectrum, using not efficient methods of allocating static spectrum, in cognitive radio networks dynamic accessing spectrum is functional. Utilizing opportunistic a Spectrum requires recognition of routing parameters and metrics in cognition radio networks, which means considering fulfilling the minimum requirements of quality of service (QOS) secondary users need to use the allowed range of primary (main) users. Since primary users are prior to use the spectrum, when primary and secondary users coexist, they need to monitor the bandwidth of the authorized spectrum. One of the most important stages to excess the dynamic spectrum is to explore it. Detection of the presence of the authorized users by unauthorized users is one of the things done in this stage, which is called spectroscopy. In the next stage, we used the analyzed information I was spectroscopy, to decide on accessing the spectrum. cognition radio is defined as a smart wireless communication system, which is aware of the environment and changes its job variables like power forward, type of modulation, carrier frequency etc. using environment learning. For further explaining routing metrics, we try to compare routing metrics in cognitive radio networks and wireless network and analyze its challenges in one-way routing and in multi-route routing

A link-quality-aware graph model for cognitive radio network routing topology management

Wireless communications is one of the fastest growing fields in the world; however this creates a problem since all wireless signals are fighting for the same limited amount spectrum in any given space. The underutilization of licensed spectrum has created a need for a new way to use it. Cognitive Radio Networks and Dynamic Spectrum Access are a solution to this problem. By opportunistically using spectrum, devices can gain access to more wireless bandwidth while not violating FCC regulations. The concepts of Cognitive Radio Networks and Dynamic Spectrum Access are very new topics and have yet to be fully explored. One of the current goals in this area is adapting existing concepts in networking algorithms to be aware of and to take advantage of a Dynamic Spectrum Access environment. Awareness and using cross-layer design enables opportunistic use of the spectrum and allows devices to take full advantage of the nature of the Dynamic Spectrum Access environment. This thesis explores some existing solutions to the Dynamic Spectrum Access problem, and uses them as inspiration to create a Link-quality-aware Graph Model for Cognitive Radio Network Routing Topology Management

Joint Channel Assignment and Opportunistic Routing for Maximizing Throughput in Cognitive Radio Networks

In this paper, we consider the joint opportunistic routing and channel assignment problem in multi-channel multi-radio (MCMR) cognitive radio networks (CRNs) for improving aggregate throughput of the secondary users. We first present the nonlinear programming optimization model for this joint problem, taking into account the feature of CRNs-channel uncertainty. Then considering the queue state of a node, we propose a new scheme to select proper forwarding candidates for opportunistic routing. Furthermore, a new algorithm for calculating the forwarding probability of any packet at a node is proposed, which is used to calculate how many packets a forwarder should send, so that the duplicate transmission can be reduced compared with MAC-independent opportunistic routing & encoding (MORE) [11]. Our numerical results show that the proposed scheme performs significantly better that traditional routing and opportunistic routing in which channel assignment strategy is employed.Comment: 5 pages, 4 figures, to appear in Proc. of IEEE GlobeCom 201