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The resource allocation problem for the downlink of orthogonal frequency division multiple access (OFDMA) wireless multicast systems is investigated. It is assumed that both the base station (BS) and a user are equipped with a single antenna, and the allocation unit is not the subcarrier, as in conventional OFDMA systems, but a set of contiguous subcarriers referred to as a "chunk". The...
This article solves the resource allocation problem for the downlink of a multi-cell, multiservice Wireless Mobile Communications System (WMCS) with heterogeneous architecture deployed into an urban environment using Orthogonal Frequency Division Multiple Access (OFDMA) in its physical level. The optimization model aims to equitably satisfy services to users by making an efficient use of the available...
Interference Alignment (IA) is a technique for mitigating the interference in wireless networks. While previous studies have mainly focused on theoretical gains and algorithms, this paper goes a step further, by assessing IA incorporated to a Coordinated Multi-Point (CoMP)-like network. IA algorithms have been well studied in terms of transmissions performance and signaling cost, albeit for fixed...
Multi-stage switching is very suitable for implementing interconnection systems operating at different physical scale (from rack-to-rack to on-chip) and with several technologies (either photonics or electronics). Several multistage architectures have been proposed to design these systems in a highly modular and efficient way. Since these proposals are general and applicable to a vast range of technologies,...
Falls are the number one cause of fractures, trauma, loss of independence and death among older adults. Each year more than 1.6 million older U.S. adults go to emergency departments due to falls [1]. It is necessary to provide mechanisms to detect people's falls in order to improve their lives. This paper proposes a fall detection system that utilizes a 2D camera. It employs an open source library...
This paper shows the vulnerabilities of the 802. Hi Wireless Networks. We propose two lab scenarios capturing the management and control frames for analysis in Wireshark followed by a comparison of the advantages and disadvantages of each scenario in order to implement the best option in a real world setting. The first test scenario involves an access point with the capacity to have a Sniffer installed...
Video streaming services have been developed using different approaches. Peer-to-peer (P2P) streaming is a competitive technique in the distribution of video contents, thanks to its collaborative and sharing features. Nowadays, several applications distribute television contents over a P2P platform, broadcasting plenty of channels to an increasing audience. The performance of such applications over...
Machine-type Communication (MTC) enables devices to exchange information in an autonomous way without human intervention. Hence, new applications can be developed benefiting from a richer awareness of the surrounding environment. However, the deployment of MTC over cellular networks creates new challenges to the contention-based Random Access (RA) procedure as well as to resource allocation for MTC...
Today's growth in the demand for access bandwidth is driven by the success of the Video-on-Demand (VoD) bandwidth-consuming service. At the current pace at which network operators increase the end users' access bandwidth, and with the current network infrastructure, a large amount of video traffic is expected to flood the core/metro segments of the network in the near future, with the consequent risk...
We propose a novel algorithm to solve the Routing and Spectrum Allocation (RSA) problem in dynamic flexible grid optical networks. Unlike most previous proposals, the algorithm solves the R and SA problems jointly by exhaustively searching the solution space and taking the network state into account. As a result, the shortest possible path with enough spectrum availability is allocated to establish...
Reducing the energy consumption of wireless networks is one of the fundamental objectives of green networks. While the use of dynamic frequency scaling has been proposed for reducing the energy consumption, they increase the packet delays and loss rates in the network. This paper addresses the problem of optimally selecting the clock frequency for wireless network interface cards with dynamic frequency...
Reed-Solomon codes are widely used to provide reliable communication, as they are well known for their high data correction rates. However, techniques that best optimize hardware area as well as signal propagation delays are needed in today's applications. In this work, two techniques are investigated and implemented using a hardware description language, synthesized to a XUPV5-LX110t development...
Millimeter-wave (MMW) is a probable technology for the future cellular systems. Its main challenge is achieving sufficient operating link margin, and directional beamforming with large antenna arrays may be a viable approach. With bandwidths on the order of gigahertz, high-resolution analog-to-digital converters are a power consumption bottleneck. One solution is to employ an hybrid implementation,...
Multimode terminals designed for heterogeneous wireless networks (HWNs) have the capability to support two or more classes of calls simultaneously. When a multimode terminal having an ongoing call initiates a new class of call, the current radio access technology (RAT) may not support the new class of call thereby necessitating a vertical handoff to a RAT that can support both the current and the...
A volcano monitoring system plays a key role for launching emergency early warning, and the use of alternative technologies have proven their effectiveness in this setting, which is the case of wireless sensor networks. For surveillance systems, the real-time requirement is mandatory due to the need for immediate access to the signals derived from a natural disaster where the goal is safeguarding...
Experimental studies in wireless sensor networks reveal a region with random packet loss and highly unreliable links. Some studies refer to the region as the Grey Area. This area may affect upper layer protocol performance. Unlike previous studies, our paper presents an experimental study of link performance using three different hardware platforms: one for Radio Frequency Identification (RFTD) and...
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