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Utilising multiple channels can increase the wireless ad hoc network capacity. Receiver Directed Transmission protocol (RDT) is designed to provide multichannel access using a single radio interface. RDT introduces a clever approach to support channel assignment and negotiation without relying on a control channel or time synchronisation. Protocols based on the RDT scheme normally use an extra radio...
This paper tackles the discovery issue in device-to-device (D2D) networks. Quick discovery is a fundamental step to realize low latency D2D communications. Assuming a synchronized superframe structure among peer devices, we propose to introduce and use common channel and group channels. Rules and procedures are defined for the purpose of enabling quick discovery. Computer simulations are performed...
Escalation in mobile devices has powered the demand for wireless networks. With the ripening of industry standards and the deployment of wireless networking across a broad commercial section, wireless technology has expanded over the age. Wireless ad-hoc network technologies and standards such as IEEE 802.11s (WANET) are efficient, economic, simple to send, permit the brisk setup of a remote system...
Dedicated short range communication (DSRC) has been allocated (3 EU, 7 US) dedicated channels at 5.9GHz for vehicular communications. Although resource allocations on the Control Channel (CCH) reserved for safety-related applications have been well investigated, efficient usage of the other Service Channels (SCH) has attracted less attention. In this paper, we propose the design of an asynchronous...
Cognitive radio technology solves the problem of spectrum underutilization by allowing the unlicensed users to opportunistically access available spectrum without affecting the activity of licensed user. Channel assignment and routing in cognitive radio networks is especially challenging in networks where nodes are equipped with only a single transceiver (as is the case in commodity wireless networks...
Multi-channel MACs have recently attracted significant attention in wireless networking research because they possess the ability to exploit multiple frequency bands in order to increase the capacity of wireless ad hoc networks. A number of multi-channel MACs have been proposed in the last few years. However, these protocols rely on two rather impractical assumptions: low channel switching latency...
In this paper, we propose a TDMA based multi-channel MAC protocol to improve the channel efficiency and network performance in wireless ad hoc networks. There are two main problems encountered in all related works in designing multi-channel MAC protocols. The first problem is the rendezvous problem and the second is multi-channel hidden node problem. In order to solve these problems, most of previous...
When the crypto-period is expired or the key is compromised, trusted third party (TTP) broadcasts the materials of key update. The method cannot guarantee that all the nodes access to key materials in time if nodes work on different spectrums in cognitive radio networks. This paper presents a new algorithm based on the logistic model (KULCR) which reduces the demand for network synchronization and...
This paper proposes a RSU assisted multi-channel coordination MAC (RAMC) protocol that fully utilizes all DSRC channels to provide simultaneous safety and non-safety communications. Within the radio range of a roadside unit (RSU), vehicles are free to tune to any service channels. The RSU monitors all the safety messages being transmitted in both the control and service channels. Periodically, the...
The upcoming IEEE802.11p/WAVE (wireless access for vehicular environment) standard is intended to deliver both safety and non-safety applications to vehicles on the roads. Despite huge research on safety traffic, only a few works have investigated non-safety comfort and entertainment applications (e.g., multimedia, web browsing, e-maps) when considering the WAVE standard features and capabilities...
Thinking of multiple frequency channels in wireless ad hoc networks can significantly improve the throughput if advanced MAC protocols are employed. The efficiency of multichannel protocols mainly depends on the channel assignment strategy, which has to assure both fairness and low signaling overhead. Taking into account these needs, the present work proposes a new multichannel MAC protocol, based...
A flexible Wireless Sensor Network platform for easier implementation of diverse applications has been developed and deployed at one of the Institute Superior Tecnico - Technical University of Lisbon (IST-TUL) campus. Since its initial deployment in 2007, this test-bed has grown steadily, supporting new nodes, applications and experiments. However, some initial problems, which were solved on an ad...
Extending system lifespan by managing power on mobile nodes is critical and primordial in wireless ad hoc networks. Recent work has shown that, by appropriately powering off nodes, energy may be significantly saved, especially when node density is high. Such approaches rely on the selection of a virtual backbone of the topology to forward ongoing traffic, coupled with functions to reorganize (manually...
Anti-jamming capability and protection against interception are key priorities in wireless mobile ad hoc networks (MANETs) or sensor networks for military applications. These features are supported by spread spectrum (SS) techniques such as frequency hopping (FH). In an FH ad hoc network, the phase of hopping sequence, i.e., FH-code phase is typically derived from the local clock reading of each node...
We propose QUEST (QUality ESTimation), a new method that accurately estimates IEEE 802.11 wireless link quality with no in-band signaling overhead. Existing link quality estimation methods either are based on hello exchanges by fixing or varying transmission rates or rely on the history (e.g., delivery ratio) of previously sent data packets in a per-rate/-neighbor manner. QUEST on the other hand,...
This paper demonstrates how to use multiple channels to improve communication performance in Wireless Sensor Networks (WSNs). We first investigate multi-channel realities in WSNs through intensive empirical experiments with Micaz motes. Our study shows that current multi-channel protocols are not suitable for WSNs, because of the small number of available channels and unavoidable time errors found...
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