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Video sensor networks (VSNs) offer an alternative to several existing surveillance technologies. However, unlike in conventional sensor network, video processing and transmission requires large amount of resources both in signal processing, i.e., encoding, and transmission of the encoded data. For such networks, an optimal encoding power and rate allocation method based on a power-rate-distortion...
Femtocell network is an efficient configuration to improve coverage and quality of service (QoS) in cellular networks. However, due to dense deployment, users in a femtocell may be interfered by the base stations nearby, resulting in a deteriorated throughput of the femtocell. In this paper, we investigate the resource allocation problem targeting at max-min throughput of the femtocells. Under the...
Building upon recent advances in radio over fiber (RoF) technology, in this paper we propose a novel architecture comprised of a distributed antenna system (DAS) and a central processing unit which are connected through an optical fiber backbone. The flexibility of the fiber-connected DAS architecture facilitates deployment of various broadband wireless access networks in an efficient manner. In particular...
Wireless mesh network (WMN) is an emerging technology for last-mile broadband Internet access. Despite extensive research on and even commercial implementations of WMNs, there are still some serious performance issues in the transport layer, where the performance of Transmission Control Protocol (TCP) degrades dramatically as the number of hops increases. Improving TCP performance over WMNs is a research...
We present a new approach to identifying and verifying the location of wearable wireless sensor nodes (W2SNs) placed on a body by inferring differences in altitudes using atmospheric air pressure sensors. This technique is aimed at long-term, in-home monitoring applications of the elderly and patients with chronic conditions, where the user has the freedom to install and remove the W2SNs as required...
Spectrum sensing is one of the key technologies to realize spectrum reuse and increase the spectrum efficiency in cognitive radio networks (CRNs). In this paper, we study energy-efficient cooperative multi-channel spectrum sensing in CRNs. We first propose a cooperative spectrum sensing and accessing (CSSA) scheme for all the secondary users (SUs). The SUs cooperatively sense the licensed channels...
In this paper, we study cooperative transmissions over CR relay networks with imperfect spectrum sensing. More specifically, we formulate the CR relay selection problem as a partially observable Markov decision process. By integrating the spectrum sensing at physical layer, the spectrum access protocols at medium access control layer, as well as the concept of effective capacity at data-link layer,...
In this paper, we propose a novel routing protocol, WLAN-WiMAX Double-Technology Routing (WWDTR), for routing packets in the heterogeneous vehicular network. Any given route in the protocol can be generally formed of a combination of WLAN and WiMAX hops. WWDTR uses the position-based routing approach over the parts of the route in which packets are forwarded via WLAN radios, in order to handle relatively...
In conventional WLANs, stations (STAs) select access points (APs) using the existing scheme based on the current quality of links. However, some novel improved architecture of WLANs is proposed with cognitive radio (CR) to negotiate spectrum usage, where the existing AP selection scheme might not be suitable for it. Thus in this paper, a new optimal AP Selection based on Restless Bandits (APSRB) scheme...
In cognitive radio (CR) networks, cooperative relaying is emerging as a key technology to improve the performance of secondary users (SUs), while ensuring the quality of service of primary transmissions. Most previous work considers maximizing physical layer throughput as a design criterion. However, the end-to-end Transmission Control Protocol (TCP) performance perceived by SUs is largely ignored...
Security is an important issue in mobile ad hoc networks (MANETs). However, security schemes have significant impacts on throughput. That is because 1) they need some overhead and consume some network resources, thus decrease throughput consequently, 2) most previous works consider security and throughput separately in designing a MANET, which can not achieve an overall optimization of network performance...
Cognitive Radio (CR) is an essential technique for the future generation green communication paradigm owing to its inherent advantages of adaptability and cognition. The compulsory spectrum sensing is a critical component to facilitate systems co-existence. In this paper, we propose a new Time-Division Energy Efficient (TDEE) sensing scheme in which the sensing period is divided into an optimal number...
Effective context-aware broadcasting of information to the areas of interest (AoI) is a challenging problem in vehicular ad-hoc networks. It is usually assumed that the information about these AoI is known a priori, either by a centralized source of information or by the entire set of vehicles. In this paper, we propose a self-adaptive broadcasting scheme based on distributed reinforcement learning,...
Viewed as an integral part of the smart grid, the Smart Home provides users the convenience, comfort and energy efficiency through centralized control of lighting, HVAC, appliances, and other home systems. Zigbee's low power consumption, build-in security method and operating on ISM bands make it one of the winner solutions for Smart Homes. Nevertheless challenges are raised to connect home devices...
The smart grid is a new advanced electrical network promoted by the government to address environmental sustainability, energy generation, distribution and consumption efficiency issues. As one of the enabling technologies, Advanced Metering Infrastructure refers to systems which measure, collect and analyze energy usage, and interact with advanced devices such as smart meters through various communication...
For transmission control protocol (TCP), CUBIC is a TCP-friendly high-speed variant, in which the window size is a cubic function of time since the last loss event. TCP CUBIC is implemented in Linux operating systems and performs well in wired networks with large bandwidth-delay product. Most of the evaluations of TCP CUBIC are conducted via simulations or experiments. Analytical models for TCP CUBIC...
The process of admitting secondary spectrum users via spectrum auctions provides a convenient framework for the primary license holder to control utilization of its idle resources. While most existing solutions in the literature are static, offline auction mechanisms, the dynamics of arrival and departure of secondary bidders, as well as the uncertainty of availability of a given sub-channel for leasing...
We consider the issue of fairness in scheduler design for distributed cognitive radio networks (CRN). We first distinguish between intra- and inter-class fairness as a result of hierarchical resource access right in a secondary spectrum allocation regime. Further, we develop a timer mechanism to achieve round-robin, max-min and proportional fairness for intra-class scheduling in a CRN. The case of...
A wireless body area sensor network (WBASN) is a wireless networking technology that interconnects tiny nodes with sensing capabilities in, on or around a human body. The vital-sign information collected by these sensors can then be used by care-givers to assess the health of a patient. Therefore, it is necessary to provide reliable communication services to prioritized WBASN data streams with quality...
Mobile Nodes (MNs) in the Mobile Ad hoc Network (MANET) employ multi-hop relaying techniques to exchange messages. These MNs are not globally reachable by nodes in the Internet. Adding Mobile IP protocol capabilities to MANETs grants the MNs the required Internet reachability. Several security and performance issues are introduced as a result of incorporating MANETs with Mobile IP. In this paper,...
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