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Long Term Evolution (LTE), the next-generation network beyond 3G, is designed to support the explosion in demand for bandwidth-hungry multimedia services that are already experienced in wired networks. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers functionality to transmit MBMS over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted...
A new Deferred Routing approach for future wireless networks, focused on large scale mobile and dynamic networks, is described. A hierarchy is defined in order to maintain different routing granularity levels to each network cluster. This allows an efficient management and dissemination of the necessary routing information, as well as resilience in mobility scenarios, for the usage of Deferred Routing...
In this paper we study the performance and complexity tradeoff of filtered multitone modulation (FMT) in statistically representative indoor radio channels. We consider two design approaches. The first one is based on the use of long prototype pulses with high sub-channel frequency confinement. The second one follows an orthogonal design with minimal length pulses (down to the length of one transmitted...
Shannon's paper in 1948 has enticed researchers to explore the capacity of networks. Roughly two decades later, van der Meulen introduced relay channels and Cover introduced the idea of broadcasting and taking advantage of spatial diversity. Since then, numerous researchers have placed their focuses on different aspects of peer-to-peer networks. This paper covers three different bounds that deal with...
We discuss the accuracy of a mechanism, called Oracle, to assess position and transmission ranges in VANET. We prove that, in the best case, the assessments of the oracle are exact. Moreover, we prove that the average case of the Oracle coincides with its best case. Therefore the Oracle is optimal. The errors that afflict the assessments of both the positions and the transmission ranges depend on...
Recently, a cooperative paradigm in cognitive radio networks, where licensed user can leverage its own bandwidth to unlicensed user in exchange for relaying its traffic, has been advocated to further improve all participates' performance. However, it entails that all participates interrupt their communication in each time slot. We propose BBC, a novel bargaining-based cooperation mechanism. It allows...
Recent development in the field of Wireless communications and electronics has enabled the deployment of Wireless sensor Networks (WSNs) in an expanding variety of applications. Significantly, wireless communications have demonstrated profound significance in a variety of applications ranging from military to health applications and from home to industry. In WSNs, a major goal is conserving the sensor...
It has long been known that adaptive beamforming has the potential to enhance the performance of wireless ad hoc networks significantly. However, due to the decentralized nature of such infrastructure-less networks, it is not straight forward to fully realize the potential performance gains of beamforming in a realistic manner. To this end we devise a fully distributed cross-layer concept, comprising...
This paper considers the use of precoding in MIMO-OFDM systems based on deterministic channel state information at the transmitter (CSIT). The proposed technique combats subcarrier fading using a linear spreading of the source information in the spatial and frequency domains. Unlike previous works, it is assumed that the receiver does not necessarily has to rely on linear processing, allowing in this...
To understand the complex behavior of a mobile ad hoc network, it is often necessary to proceed through the instantiation of a convenient theoretical model which can explain this behavior. The modeling tool we use in this paper is Erdös-Rényi approach. It emanate from random graph theory. Furthermore, since mobile wireless ad hoc and sensor networks are typically limited in memory resources and...
This paper describes a scheme for providing mobile multimedia applications, distributed in a Wireless Local Area Network (WLAN), with seamless communications. Specifically, when multiple WLAN access points are available, the scheme enables a mobile node to select dynamically the access point to connect with, based on a combination of measured parameters such as signal strength, transmission rate,...
The scope of this paper is the interdisciplinary measurement and modeling methodology of Quality of Experience (QoE) when playing a mobile location-based massively multiplayer online role-playing game (MMORPG) that places the virtual world on top of the real world using the user's location. The paper introduces the implementation of a re-usable mobile QoE measurement framework on the Android platform...
In order to construct a radio environmental map that can help navigating secondary communication in TV bands, we present a new method of interference source localization for cognitive radio networks. Our low-cost, high-precision localization method, operates without any prior knowledge of the interference source other than transmitter power. It can be divided into two steps: an estimation step at...
In the study of the wireless mobile network, Random waypoint mobility model (RWP) and its generalization, nonuniform RWP (NU-RWP) are two of the most widely used mobility models. A useful property in NU-RWP, namely the inter-arrival time (IAT) is studied in this paper. We analytically derive the relationship between waypoint distribution and IAT, and propose two estimation schemes for the evaluation...
In this paper we present a design methodology and system prototyping for the baseband level of the Software Defined Radio (SDR)-based portable multi-standard terminal. The SDR-based architecture consists of three main layers denoted as: i) Upper Layer to provide communication with an end user and a network; ii) Middle Layer to establish the required protocol configuration; and iii) Bottom Layer to...
We consider content discovery and provision in wireless networks with infrastructure, where mobile nodes store, advertise and consume contents while Broker entities running on infrastructure devices let demand and offer meet. We refer to this paradigm as match-making, and study its performance in terms of query success probability, i.e., the probability that a content query is successful. To ensure...
Recent studies demonstrate that Cognitive Radio (CR) technology can increase the spectrum efficiency of wireless systems, provided that the activity of primary users (PUs) must be carefully protected. For this reason, several sensing schemes leverage the cooperation among nodes to increase the accuracy of PU detection. In this paper, we propose to employ the CR principles in the vehicular environment...
OFDMA based cellular radio networks aim to operate as close as possible to frequency reuse distance of one, where the whole spectrum would be available in every cell. Modern systems are able to adjust parameters such as transmission power, modulation, and coding separately for each frequency sub-channel on a very short time scale. This way Fractional Frequency Reuse (FFR) can be applied, allowing...
Packet-combining schemes are an attractive improvement to ARQ schemes, since they allow receivers to keep the good parts of an otherwise erroneous packet and use these with good parts from subsequent packets to allow for quicker decoding. In the previous paper a memory-efficient hard-decision packet combining scheme has been described and analysed, which relies on intermediate checksums spread into...
We propose a simple but effective algorithm to formulate growable communication graphs that exhibit (i) fast information dissemination, (ii) high scalability with negligible performance degradation, and (iii) very small diameter and short average path length. In particular, we use Borel Cayley Graphs (BCGs) as base network topologies. Previously, we reported that BCGs are one of the fastest information...
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