Results 1 -
7 of
7
Spectrum-Aware Opportunistic Routing in Multi-Hop Cognitive Radio Networks
"... Abstract—In this paper, cognitive routing coupled with spectrum sensing and sharing in a multi-channel multi-hop cognitive radio network (CRN) is investigated. Recognizing the spectrum dynamics in CRN, we propose an opportunistic cognitive routing (OCR) protocol that allows users to exploit the geog ..."
Abstract
-
Cited by 12 (5 self)
- Add to MetaCart
(Show Context)
Abstract—In this paper, cognitive routing coupled with spectrum sensing and sharing in a multi-channel multi-hop cognitive radio network (CRN) is investigated. Recognizing the spectrum dynamics in CRN, we propose an opportunistic cognitive routing (OCR) protocol that allows users to exploit the geographic location information and discover the local spectrum access opportunities to improve the transmission performance over each hop. Specifically, based on location information and channel usage statistics, a secondary user (SU) distributedly selects the next hop relay and adapts its transmission to the dynamic spectrum access opportunities in its neighborhood. In addition, we introduce a novel metric, namely, cognitive transport throughput (CTT), to capture the unique properties of CRN and evaluate the potential relay gain of each relay candidate. A heuristic algorithm is proposed to reduce the searching complexity of the optimal selection of channel and relay. Simulation results are given to demonstrate that our proposed OCR well adapts to the spectrum dynamics and outperforms existing routing protocols in CRN. Index Terms—Cognitive radio, multi-hop transmission, opportunistic routing, dynamic spectrum access. I.
SUM: Spectrum Utilization Maximization in Energy-Constrained Cooperative Cognitive Radio Networks
"... Abstract—Cooperative cognitive radio networks (CCRNs) en-able secondary users (SUs) to access primary resource by cooperation with active primary users (PUs). For the cooperation-generated resource, existing schemes in CCRNs allocate the re-source only to the relay SUs. However, this may lead to ine ..."
Abstract
- Add to MetaCart
Abstract—Cooperative cognitive radio networks (CCRNs) en-able secondary users (SUs) to access primary resource by cooperation with active primary users (PUs). For the cooperation-generated resource, existing schemes in CCRNs allocate the re-source only to the relay SUs. However, this may lead to inefficient spectrum utilization, when the relay SUs have poor channel condition or little traffic load for their own secondary trans-missions. In this paper, considering user diversity in secondary networks, we focus on network-level throughput optimization for secondary networks, by allowing all SUs to optimally share the cooperation-generated period. Besides, considering the energy constraint on SUs, we formulate the resource allocation problem from long-term perspective, to reflect the time-varying change of user diversity in channel condition, traffic load and energy amount. We present an online SUM scheme to solve the long-term optimization problem. Although a mixed-integer and non-convex problem is involved in the SUM scheme, we transform the problem into multiple convex subproblems, and then optimally solve it with low computational complexity. Extensive simulations show that the proposed SUM scheme significantly outperforms the existing schemes. Index Terms—cognitive radio, cooperative communication, resource allocation, energy consumption. I.
Network Coding-Based Multicast in Multi-Hop CRNs under Uncertain Spectrum Availability
"... Abstract—The benefits of network coding on multicast in tradi-tional multi-hop wireless networks have already been demonstrat-ed in previous works. However, most existing approaches cannot be directly applied to multi-hop cognitive radio networks (CRNs), given the unpredictable primary user occupanc ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract—The benefits of network coding on multicast in tradi-tional multi-hop wireless networks have already been demonstrat-ed in previous works. However, most existing approaches cannot be directly applied to multi-hop cognitive radio networks (CRNs), given the unpredictable primary user occupancy on licensed channels. Specifically, due to the unpredictable occupancy, the channel’s bandwidth is uncertain and thus the capacity of the link using this channel is also uncertain, which may result in severe throughput loss. In this paper, we study the problem of network coding-based multicast in multi-hop CRNs considering the uncertain spectrum availability. To capture the uncertainty of spectrum availability, we first formulate our problem as a chance-constrained program. Given the computationally intractability of the above program, we transform the original problem into a tractable convex optimization problem, through appropriate Bernstein approxi-mation together with relaxation on link scheduling. We further leverage Lagrangian relaxation-based optimization techniques to propose an efficient distributed algorithm for the original problem. Extensive simulation results show that, the proposed algorithm achieves higher multicast rates, compared to a state-of-the-art non-network coding algorithm in multi-hop CRNs, and a conservative robust algorithm that treats the link capacity as a constant value in the optimization. I.
Distributed Energy Efficient Cross-layer Optimization for Multihop MIMO Cognitive Radio Networks with Primary User Rate Protection
"... ar ..."
(Show Context)
Multicasting in Cognitive Radio Networks: Algorithms, Techniques and Protocols
"... ar ..."
(Show Context)
Pathway Collection below Resource Constraints in Multihop Cognitive Radio Networks M.Vanitha
"... Abstract- Cognitive Radio (CR) is an emerging technology to solve the spectrum underutilization problems by opens the licensed spectrum bands for opportunistic usage and initiates spectrum trading to improve the spectrum utilization. The path selection problem in multihop cognitive radio networks (C ..."
Abstract
- Add to MetaCart
Abstract- Cognitive Radio (CR) is an emerging technology to solve the spectrum underutilization problems by opens the licensed spectrum bands for opportunistic usage and initiates spectrum trading to improve the spectrum utilization. The path selection problem in multihop cognitive radio networks (CRNs) are investigated below constraints on flow routing, link scheduling and CR source’s budget. Cognitive Radio session-based spectrum trading develops the spectrum trading mechanisms that are very effective based on the cross-layer optimization in multi-hop CRNs. New service provider, called secondary service provider (SSP) helps CR sessions to select the paths for packet delivery. The SSP purchases the licensed spectrum and jointly conducts flow routing and link scheduling under the budget constraints. A 4D conflict graph is used to characterize the conflict relationship among CR links and objective of maximizing the end-to-end throughput. The heuristic algorithm used to solve the NP-hardness of the problem and finding the path with source budget. The heuristic algorithm considers only single path routing which decreases the network performance. In order to increase the network performance the Multipath Routing and Spectrum Access algorithm has been proposed.
