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In this paper, we investigate cooperative architectures and cloud formation mechanisms within the concept of mobile clouds, where multi-standard multi-radio devices in close proximity communicate to each other over short-range radio links while preserving connectivity to the overlay cellular network. Four architecture approaches are considered, namely a central cellular controlled, a cloud leader...
Retrieval process of original symbols of a spread spectrum based communication system is tried to be improved by Gradient Algorithm (GA) and Blind Source Separation (BSS) principles. Two simple schemes, based on two energy functions are presented. Time correlation properties of the channel are used as advantages in developing the filter coefficients for the receiver. Direct Sequence - Code Division...
Cognitive radio is a smart wireless communication concept that is able to promote the efficiency of the spectrum usage by exploiting its free frequency bands, namely spectrum holes. Detection of spectrum holes is one of the first steps of implementing a cognitive radio system. Another step towards the feasibility and a real implementation of a cognitive radio network is the problem of location awareness...
Traditional transport layer protocols have been designed to perform end-to-end error control transparently to the intermediate nodes (e.g., TCP). However, the resource constraints featured by Wireless Sensor Network (WSN) require a different paradigm where intermediate nodes are able to cache packets and if possible retransmit them on-demand to avoid incurring costly end-to-end retransmissions. Lately,...
In this paper we present an approach to provide efficient low-complexity video encoding for wireless sensor networks. We present a method based on removing the most time-consuming task, that is motion estimation, from the encoder. Instead the decoder will perform motion prediction based on the available decoded frame and send the predicted motion vectors to the encoder. We present results based on...
Wireless Visual Sensor Network (WVSN) is formed by deploying many Visual Sensor Nodes (VSNs) in the field. The VSNs acquire images of the area of interest in the field, perform some local processing on these images and transmit the results using an embedded wireless transceiver. The energy consumption on transmitting the results wirelessly is correlated with the information amount that is being transmitted...
Disruptions, high dynamism and no end-to-end communication are some of the Vehicular Delay-Tolerant Networks (VDTNs) main characteristics. This paper describes the implementation of a new VDTN multicast routing protocol which makes use of knowledge about previous encounters to estimate congestion and density and better spread data bundles and limit the number of copies to reduce overhead. After a...
In ad hoc networks, the mean degree represents the average number of neighbors per station. The larger this value, the better the connectivity of the network. A direct consequence for the stations is that, when the mean degree increases, exchanging information becomes easier. In this work we study the sensitivity of the mean degree according to the variation of several characteristics related to the...
In this paper, we consider the problem of resource allocation in two-tier networks taking into consideration nondense femtocell deployments. The following limitations can be remarked from the prior work in the field of resource allocation: (1) resources are underutilized due to the equal power distribution in macrocell, (2) access to public users in femtocells is restricted to avoid depriving own...
Maximum likelihood detection (MLD) has been shown to offer large performance gains within the context of linearly precoded MIMO-OFDM systems with multiple-stream transmission when compared to an all-linear setup (i.e., linear transmitter/receiver), although at the cost of a higher computational complexity. To overcome this handicap, this paper proposes a method to selectively choose the detection...
Rank-based policies represent a promising approach for designing message forwarding algorithms that meet the needs of opportunistic networks. In fact, they combine low computation and communication costs with good performance in terms of both latency and delivery rates. Nonetheless, they highly depend on the mobility scenario relevant to the user, and a forwarding policy with good performances in...
A variety of personal backup services now allow users to synchronise their files across multiple devices such as laptops and smartphones. These applications typically operate by synchronising each device with a centralised storage service across the Internet. However, access to the Internet may occasionally not be available, leaving any unsynchronised content in a vulnerable state. To address this,...
Nowadays, research on Vehicular Technology aims at automating every single mechanical element of vehicles, in order to increase passengers' safety, reduce human driving intervention and provide entertainment services on board. Automatic trajectory tracing for vehicles under specially risky circumstances is a field of research which is currently gaining a lot of attention. In this paper we show some...
Transporting raw data which is usually correlated over multi-hop wireless links can be costly both in terms of time as well as resources. This is likely to be a pressing problem particularly in the emerging Machine-to-Machine (M2M) communication paradigm wherein the amount of data is expected to proliferate. With in-network processing and data aggregation, the total amount of forwarding traffic on...
In wireless sensors networks (WSNs) the efficient use of the sensors' energy is a key point to extend the network lifetime and has been the center of attention by many researchers. There are several different techniques to reduce the sensor's energy consumption. Sensor node clustering is one of these techniques. However, finding an optimal clustering in WSNs is a NP-Hard problem, thus efficient heuristics...
The extended Kalman filter (EKF) is an important tool in wireless sensor networks for localization and tracking of a dynamic target. The performance of the EKF is heavily dependent on the mathematical model used for target dynamics. Significant research has been done for finding an optimum state estimation model for target motion. In this paper we propose a new mobility model for target movement simulations...
Wireless mesh networks (WMNs) are next generation networks that have emerged as a promising technology capable of providing broadband connectivity at low cost, and offers advantages in scenarios where cabling is too expensive or prohibitive. Rural communities are a good example of these kind of scenarios. Deployment of WMNs in rural communities can be done with a low budget, and expansion of the network...
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