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The unit disk graph model is widely used in conjunction with position-based routing. Past research has suggested that this leads to inefficient routing strategies and improved metrics have been proposed that combine packet reception rate and progress. In this paper we revisit the earlier analysis and show that a blacklisting scheme based on packet reception rate is more energy efficient. We also show...
In this paper, we propose a novel energy efficient cooperative duty cycle MAC (EECDC-MAC) protocol in which sensor nodes use fixed wakeup rendezvous scheduling to exchange messages and a cooperative transmission mechanism to avoid overuse of nodes with lower residual energy. Numerical results demonstrate that the EECDC-MAC protocol can prolong the entire network longevity efficiently in comparison...
In this paper we investigate how recent advances in wireless communications can be integrated with agent-base service applications so that the connectivity between different users of the same environment, or remotely connected ones, is improved. We present two agent-based mobile service applications that employ software agents to represent end-users. We show how these applications are providing essential...
High peak to average power ratio (PAPR) of a transmitted signal is one of the major drawbacks of the complex wavelet packet modulation (CWPM) as usual in any multicarrier communication system. Utilizing the advantage of concentrating the energy to certain subspaces of the discrete wavelet transform, many PAPR reduction techniques are proposed to solve this problem like threshold and clipping methods...
Advances in wireless communication technologies are driving the evolution toward ever faster networks in terms of throughput and latency. User Equipments (UEs) have solid processing power, cameras and displays to produce and consume rich media and services. Their multi-standard interfaces allow them to utilize network-dependent services. However, tapping the full potential of these connected services...
In this paper, we analyse the impact of the Contiki Operating System (OS), and its Carrier Sense Multiple Access and Collision Avoidance (CSMA-CA) implementation on an IEEE 802.15.4 node's throughput and wireless channel utilization. The analysis is based on Contiki's Rime networking protocol stack, and its target is to determine an upper bound for the stated metrics. We explain that in Contiki with...
Traceroute program is extensively used in wired networks to track the route packets take on their way to a destination. However, traceroute is often less effective in wireless networks where broken routes are too common. In this paper, the design of wtracert is presented that employs optimal timeouts to provide a faster implementation of the traditional traceroute. Optimal timeout period of timers...
The use of femtocells has been an attractive solution since it achieves better coverage and capacity and low cost for deployment and maintenance. However, their performance can be compromised by the cross-tier interference with existing macrocell infrastructure or between adjacent femtocells, especially in the case of co-channel deployment. One way to address this, is adjusting the transmit power...
In the vision of heterogeneous networks, the Quality of Service provided by classic cellular systems is improved thanks to a jointly adoption of macro and small-range cells (i.e., micro, pico, and femtocells) working in the same area. This rationale has been also assimilated by 3GPP, which now proposes its possible exploitation in the upcoming Long Term Evolution-Advanced architecture. In this context,...
In schedule-based asynchronous duty cycling, nodes alternate between active and inactive time slots in cycles that guarantee the occurrence of overlapping active time, therefore ensuring that neighbors will have opportunities to communicate. Among these schedules, Block Designs provide the minimal duty cycle for a given number of time slots [1]. However, there exists no precise estimation model for...
Recently, testbed deployments using real IEEE 802.11p devices have allowed making performance measurements using this technology. The results obtained in those experiments evidence that lots of factors influence wireless communications: small obstacles like trees, small moving obstacles like cars, or large obstructions like buildings. All of them affect the transmission range, reducing the communication...
In this paper, we propose three variants of WSN routing protocol: i) basic-opportunistic, ii) opportunistic with delay and iii) opportunistic with backtracking. The main idea is that a node transmits its packet to the next awake node as long as this decreases the remaining distance to the sink. The two last variants allow a packet to be discarded or moved further away from the sink if necessary. The...
Wireless sensor networks (WSNs) have received much attention in the last few years especially with regard to routing protocols and transmission power adaptation. The main goal of power adaptation is to improve the performance and the lifetime of WSNs. By selecting the suitable Transmission Power Level (TPL), the battery lifetime of sensor nodes is increased and better overall network performance is...
One of the approaches to conserving energy in WSN is to schedule some of the sensor nodes to sleep and estimate their readings from the ones of active nodes. This prediction relies on the modelling of the relationship between the sensor readings of the active and sleeping nodes. As this relationship can change over time, it is crucial to detect these changes to minimise loss in sensing fidelity. To...
Channel/queue-aware scheduling and resource allocation algorithms in MIMO-OFDMA can be regarded as a multi-objective optimization problem taking into account not only the system throughput but also the transmitted power, the QoS constraints, the priority levels of different traffic classes and the amount of backlogged data in the data link control (DLC) layer queues. Based on tools from information...
The technical evolution of Wi-Fi networks has made it possible to attain very high speeds for delivering content to users. However multicast transmissions never received the same level of attention as unicast transmissions in the IEEE802.11n standard. In this paper, we experimentally assess the viability of employing commercially available IEEE802.11n hardware to multicast real-time multimedia content,...
A wireless communication system works more efficiently if link-layer parameters are (adaptively) optimised. We now analytically find a complete link parameter vector for each of many sub-channels which satisfies the Karush-Kuhn-Tucker necessary conditions for throughput maximisation. The tangent line common to 2 (scaled) packet-success rate functions defines the switching point between the corresponding...
Vehicular Ad-Hoc Networks (VANETs) offer opportunities for improvements in driving security and comfort. Vehicles can take advantage of collaboration schemes to disseminate important information. In this article we present a a driving safety application based on warnings dissemination for smart-phones based on our eMDR protocol. The use of smartphones allows a quick development and deployment, avoiding...
ZigBee is a standard for low-power, low-rate wireless communication. It is modeled on the physical layer and medium access control defined in IEEE 802.15.4. In this paper, we study an attack on modern radios called the “Packet in Packet” (PIP) attack. We replicate the attack in ZigBee devices and discuss possible defenses against the attack. We implement a solution to thwart the PIP attack in TinyOS...
In this paper, we evaluate the impact of cognitive radio transmissions on primary radio communications. Our objective is to characterize precisely, based on the position of secondary users, the vulnerability areas where interference to primary radios can be generated. To do so, we detail all the cases where overlap regions between primary and secondary transmitters exist and derive the vulnerability...
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