1,301 research outputs found
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
Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges
With the rapid development of marine activities, there has been an increasing
number of maritime mobile terminals, as well as a growing demand for high-speed
and ultra-reliable maritime communications to keep them connected.
Traditionally, the maritime Internet of Things (IoT) is enabled by maritime
satellites. However, satellites are seriously restricted by their high latency
and relatively low data rate. As an alternative, shore & island-based base
stations (BSs) can be built to extend the coverage of terrestrial networks
using fourth-generation (4G), fifth-generation (5G), and beyond 5G services.
Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs.
Despite of all these approaches, there are still open issues for an efficient
maritime communication network (MCN). For example, due to the complicated
electromagnetic propagation environment, the limited geometrically available BS
sites, and rigorous service demands from mission-critical applications,
conventional communication and networking theories and methods should be
tailored for maritime scenarios. Towards this end, we provide a survey on the
demand for maritime communications, the state-of-the-art MCNs, and key
technologies for enhancing transmission efficiency, extending network coverage,
and provisioning maritime-specific services. Future challenges in developing an
environment-aware, service-driven, and integrated satellite-air-ground MCN to
be smart enough to utilize external auxiliary information, e.g., sea state and
atmosphere conditions, are also discussed
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
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