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Wireless sensor networks pose strict bandwidth and power constraints. In multimedia Sensor Networks classical rate distortion function may not be directly applied since timely delivery of multimedia content in sensor network may necessitate consideration of energy consumption and transmission rate in the process. Both these factors should be incorporated in classical R-D function to achieve best operational...
Various application services including multimedia applications need efficient multicast technologies, but the IEEE 802.11 protocol, which is currently the most widely used, does not specify the standard on multicast, which is, instead, substituted by broadcast or a combination of unicast. Using broadcast is, however, difficult to judge on the transmission success or fail, because it does not receive...
Being reliable and real-time, are the two most challenging requirements of wireless sensor and actuator networks (WSAN) due to the shared, error-prone and nondeterministic behaviour of wireless communication medium. In this paper, an adaptive data-rate and space-time coding (STC) scheme has been proposed for the IEEE 802.11-based Soft-Real-Time WSAN's utilizing Enhanced Distributed Channel Access...
Reliable event delivery at MAC, routing and transport level has been explored to great extent to provide improved throughput and route resilience in wireless sensor networks. The evolution of wireless sensor and actor networks (WSAN) have posed an extra constraint in terms of reliable event response. The reliable response is defined as the the in time event delivery from sensor nodes to actors and...
In multi-interface multi-channel (MIMC) based tactical ad hoc networks, QoS support is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop...
RFID technology has been broadly applied in the transportation field. It can achieve wireless communication, thus, it can be used to the vehicle identification. But special case exists, such us it faces to more than one vehicle with different speed on the urban roads. If multiple labels respond at the same time, collision will happen. In this paper, according to the different distances between reader...
There are real challenges in both the IEEE 802.11 wireless local area network (WLAN) protocol and the medium access control (MAC)-functions providing the required quality-of-service, high throughput and minimum latencies. The IEEE 802.11 layer supports both the distributed coordination function (DCF) and the enhanced DCF (EDCF). The different access categories (AC) within the EDCF can enhance the...
Distributed medium access control protocols can be classified into contention-based and contention-free protocols. In this paper, we analyse a contention-free distributed protocol where nodes make reservations on a first-come first-served basis. We evaluate the impact of this first-come first-served approach on the fairness regarding throughput and delay, by means of the ECMA-368. This standard establishes...
The acoustic propagation speed under water poses significant challenges to the design of underwater sensor networks and their medium access control protocols. Similar to the air, scheduling transmissions under water have significant impacts on throughput, energy consumption, and reliability. Although the conflict scenarios and required scheduling constraints for deriving a collision-free schedule...
Scheduling is a fundamental component in resource (bandwidth and power) management in NG wireless networks and plays the main role in providing QoS requirements such as delay, throughput and packet loss for different classes of service in 802.16d networks. In this paper we propose a novel scheduling algorithm Strict Priority Based Adaptive modulation and Coding (SP_AMC_Based) that can grantee QoS...
Supporting secondary users through a collateral network dedicated to spectrum sensing has been recently proposed as a mean to overcome spectrum sensing limitations of secondary devices. Building on this idea, we propose a protocol for a Wireless Sensor Network (WSN) to support secondary devices of an Opportunistic Spectrum Access (OSA) network. We examine the fundamental tradeoff between the statistics...
Most of the current wireless sensor networks operate on crowded unlicensed frequency bands. Especially in industrial wireless sensor applications this causes problems because of the received interference from other systems and coexistence problems with other wireless sensor networks. Multi-channel communications can be utilized to improve the performance under interference and enable coexistence of...
A 2D Markov-Chain analysis is used to model channel occupancy within a high mobility picocell based network including handover and outage events. Single-cell performance is evaluated by the Grade of Service and by the call dropping probability. The relations between different picocellular network parameters are analyzed and guidelines for proper MAC protocol design are given.
The medium access control being the main source of energy wastage in wireless sensor networks, energy-efficiency is always kept in mind while designing the communication stack. Especially, versatile preamble-sampling MAC protocols emerged to offer a suitable solution over multiple deployment characteristics. For instance, some works have targeted burst transmissions while others have focused on long-term...
BitTorrent is a peer-to-peer (P2P) file sharing protocol, which overcomes the bottleneck of server bandwidth by allowing peers to share the downloaded data directly. However, the greedy and non-cooperative behavior (such as leeching) of individual peer can degrade the performance of P2P significantly. In this paper, we optimize the non-cooperative P2P network from the game theory point of view. Specifically,...
With the popularity of navigation applications and the integration of GPS in user devices, location-awareness is becoming an essential feature demanded by users. Nevertheless, location-awareness in indoor environments is still limited by the inability of GPS to operate indoors. With a centimeter-level ranging resolution, Ultra-Wideband (UWB) is one of the most promising technologies to provide indoor...
In this paper, we discuss the challenges associated with integrating multiuser OFDMA in a single cell IEEE 802.11 based wireless ad hoc network and propose a new, dynamic and robust approach to improve it. Our new MAC, using OFDMA in the physical layer, can incorporate multiple concurrent transmissions or receptions in a dynamic manner and can adjust the collision probability based on the traffic...
In this paper, we propose a novel scheme for efficient video broadcasting on WLAN using IEEE 802.11e HCCA MAC protocol and H.264/SVC video compression technology. We rearrange an outgoing sequence of H.264/SVC NAL units according to the prioritization of their dimension, temporal, and quality scalability. In addition, our proposed scheme broadcasts the prioritized NAL units as various data-rates of...
Plant automation and control are mission-critical applications and require timely and reliable data delivery, which is difficult to provide using a wireless technology. This is especially more difficult in industrial environments with harsh radio conditions. In this paper we present a dynamic and distributed topology control algorithm for Wireless Sensor Networks for use in performance critical environments...
As a major result of the rapid population growth around the world, the number of road users, vehicles, drivers, passengers and pedestrians has increased dramatically, resulting in the need for a rapid development in transport systems to deal with everyday challenges to provide a safe, reliable, comfortable and efficient environment. In this paper, we explore the background of V2I, I2V communications...
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