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Cooperation enforcement in Mobile Ad Hoc Networks (MANET) and Wireless Sensor Networks (WSN) typically relies on separate detection and punishment schemes that isolate selfish nodes from routing and receiving network services. However, cooperative nodes then have to carry all the traffic. We propose a system that enforces cooperation smoothly and assures a fair distribution of bandwidth, as well as...
Spread spectrum multiple-access packetized wireless communications systems are considered. Although very efficient in low traffic (or low-rate) and low signal-to-noise ratio scenarios, the traditional and well-known spread ALOHA multiple access (SAMA) quickly collapses when both traffic and signal power increase. In certain situations, such as wireless sensor network traffic towards a sink, this severely...
The propagation speed of an acoustic signal is much slower than the speed of a terrestrial radio signal due to the physical characteristics of an underwater acoustic channel. This large delay can impact the throughput of the channel. There is a very high delay variance which presents unique challenges to the designs of efficient protocols. The inconsistent delay renders many traditional communication...
Wireless sensor networks (WSNs) are appealing to researchers due to their wide range of application potential in areas such as target detection and tracking, environmental monitoring, industrial process monitoring, and tactical systems. As medium access control (MAC) has a significant effect on the energy consumption, energy efficiency is one of the fundamental research themes in the design of MAC...
In order to reduce power consumption, many previously proposed MAC protocols for wireless sensor networks (WSNs) use a periodical active/sleep scheme. However, this scheme may not adapt to varying traffic conditions. A new throughput-adaptive MAC protocol (TA-MAC) is proposed in this paper, where overhearing nodes try to notify nodes a few hops away about the current transmission, therefore the latter...
It is difficult to provide QoS guarantees for streams in wireless network based on IEEE802.11 DCF because of limited bandwidth. Taking CBR traffic as example, we studied the traffic performance with different parameters in this paper. The results show that for an overloaded network, the traffic with longer packet size has greater throughput. Since the MAC layer performs the same competitive algorithm,...
We investigate the performance of IEEE 802.15.4 MAC (Medium Access Control) sublayer in beacon-enabled tree-topology Wireless Sensor Networks (WSNs). To our knowledge, current literature has mostly focused on relatively simpler star topology or non-beacon-enabled peer-to-peer networks. In our work, we first respectively evaluate the impact of different traffic loads from the source nodes in each depth...
A wireless sensor network is a network of compact micro-sensors equipped with wireless communication capability. In a wireless sensor network deployed to collect and update data, sensor nodes are usually battery-powered. Moreover, they are hardly able to support complex computation. Such unique features give rise to a critical issue; how to devise a simple energy-aware MAC scheme. Intending to resolve...
Underwater acoustic sensor networks (UWASNs) is an emerging technology, comprising of sensor nodes and unattended automated vehicles (AUVs), all working in a collaboration to sense various phenomenon, process digital information, store processed data and communicate among each other and base stations. Acoustic propagation in water is characterized by high and variable delays, fading effect, Doppler...
SMAC is a popular duty-cycled MAC protocol, designed for wireless sensor networks to save energy and prolong the network lifetime. However, existing work evaluates the performance of SMAC solely through simulations or field measurements. To the best of our knowledge, there are no analytical models for evaluating the performance of SMAC. In this paper, we propose a Markov model to describe the behavior...
Several medium access control (MAC) protocols have been proposed for wireless sensor networks with the objective of minimizing energy consumption. For example, sensor-MAC (S-MAC) was proposed to reduce energy consumption by introducing a duty cycle. Under variable traffic load, the fixed duty cycle of S-MAC results in energy loss due to idle listening along with higher latency and lower throughput...
Modified optimized link state routing (M-OLSR) has been developed for adaptability in wireless mesh networking (WMNs) scenarios and exhibits a much better scalability of traffic load and mobility in sparse and dense network. The protocol uses some refresh timers for periodic updates of link information and for subsequent topology maintenance. In this paper, we investigate the impact of configuring...
In timing analysis attackers study the transmission pattern of different nodes in a network with the goal of extracting information about users, applications, or the structure of the network, even when the traffic is encrypted. Defeating timing analysis attacks requires expensive traffic mixing measures that equalize the transmission pattern at all nodes; such measures are especially expensive for...
Tremendous efforts have been conferred towards the congestion control concern in mobile wireless networks while dealing with maximizing both throughput and fair bandwidth allocation. Unfortunately, this is made limited by the variable and unpredictable behaviour of such networks. In this paper we propose a new congestion control mechanism for multimedia traffic in mobile wireless networks. Our proposed...
Modern cellular networks commonly deploy rapid channel rate adaptation to vary the wireless capacity in response to channel conditions while maintaining a fixed target error rate (typically 1%). Although desirable in terms of throughput for inelastic applications that do not adapt to network conditions, a low fixed target error rate incurs the expense of significant power consumption, especially at...
This paper aims at improving the throughput of the wireless sensor networks (WSNs), particularly to overcome the so-called funneling effect for WSNs with converge-cast patterns. Due to the disproportionate larger number of packets accumulated in the sensors that are closer to the sink, there is a need to decrease the collisions and increase the throughput around the sink area as well as the nodes...
The foray of wireless sensor networks into time-sensitive applications demands support for emergency services with guaranteed quality of service (QoS) bounds. We introduced CP-EDCA, a channel preemptive enhancement to the IEEE 802.11e EDCA standard, for guaranteed emergency medium access in distributed wireless environments. The performance results for emergency traffic depicted 50% uniform decrease...
We consider the problem of clandestine communications, i.e., communications that are meant to be invisible to third-party eavesdroppers, in the context of wireless sensor networks. Although encryption and anonymous routing protocols can hide the content and the routing information, the transmission activities of sensors on the same route can still reveal the information flow. In this work, a perfectly...
The QoS requests of data traffic with lower priority in hotspot areas are not always satisfied in a traditional cellular wireless communication system. But on the other hand, about 60% of the channel slots allocated to a voice user is wasted due to the spurt of speech packets. In this paper, a cooperative strategy for transmitting data packets and speech spurt packets over the shared channel of voice...
A method for file transfer utilizing forward error correction (FEC) to pass traffic over deployed wireless sensor networks is studied. The entire wireless sensor network is modeled as an error-prone virtual physical link. Previous work in the area of terminal communication across the sensor network is expanded upon to include file transfer in order to provide a more capable channel and a basis for...
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