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In delay- and disruption-tolerant wireless communication networks, capacity is commonly traded off for delay. That is the case of spatial intermittent connectivity (SIC) networks. SIC networks are designed to provide high data rates to mobile nodes in small disjoint geographical areas. However, because of userspsila mobility, these high data rates come at the expense of significant connectivity delay...
PESQ is the international standard for objective speech quality measurement and has been widely used in industry for voice quality assessment for VoIP products and systems. However, current research efforts involving PESQ are mainly focused on simulated IP networks. The need remains to establish how accurate PESQ is when used in real wireless systems, especially in new wireless VoIP environment. The...
As a radio access technology for next generation cellular networks, 3GPP and 3GPP2 are standardizing long term evolution (LTE) and ultra mobile broadband (UMB), respectively. In this paper, we compare the handover schemes of both technologies in three aspects, i.e., interruption time of a user plane, required wireless resources and the overhead for avoiding packet reordering. The comparison results...
This paper introduces interference cartography, a simple and effective concept that helps detect, identify and use spectrum opportunities in a secondary spectrum usage context. Interference cartography combines measurements performed by different network entities (mobile terminals, base stations, access points) with the geo-location information and applies simple and effective spatial interpolation...
The use of licensed spectrum for wireless communication is driven by the need to control interference between different operators. However, with this mode of regulation, spectrum utilization is far from efficient and the growth of wireless networks is hindered by the shortage of free frequency bands and the vast investments for the acquisition of a license. In view of this situation, we present an...
In this paper, a concept of a network-driven adaptive video streaming is proposed and investigated in a state-of-the art UMTS/HSDPA network in order to alleviate the impact of strongly time-varying quality of wireless links on video quality. We propose making adaptation decisions in a radio access network based on channel-quality information available there. This is done by a so-called Multimedia...
This paper addresses the problem of identifying NLOS propagation by applying the statistical decision theory. A time-of-arrival (TOA) based method is developed under idealized conditions to provide a performance reference. In the presence of both TOA and received signal strength (RSS) measurements, a joint identification method is derived to efficiently exploit both the TOA and RSS measurements. Analytical...
The paper compares the findings coming from three case studies for the case of mobile data services and highlights factors that could explain the low usage rates among the users. The movement of applications from desktop platforms to wireless and mobile configurations may have a significant impact on future daily activities. Mobile computing supported by broadband wireless networks allows users to...
The development of mobile ad hoc systems have considerably emphasized the need for a better understanding of the factors that influence the systemspsila performance, i.e., mobility patterns, radio propagation, traffic characteristics and their interrelations. Depending on the context where the system is being used-whether at work, at home, or in some means of transportation-there will be various applications...
In receivers, IQ imbalances have significant effects on the performance of data transmission. Comparison of the performance of different types of orthogonal space-time block codes (OSTBC) in the presence of IQ imbalances show that different codes donpsilat have a same behavior. Although most codes have an acceptable performance in low imbalances, they canpsilat work properly in the presence of intensive...
Since ubiquitous mobile communication is already true in many countries in the future the provisioning of broadband access for mobile users is the key functionality. For mobile users the performance of the radio network vitally depends on the length and the characteristic of the transmission path between user terminal and access point. Due to the continuously changing conditions the link quality will...
Seamless vertical handover is one of the major challenges toward seamless inter-networking between heterogeneous access networks. To perform seamless vertical handover even under bad radio conditions in network mobility (NEMO) environments, NEMO-SHO has been proposed as an IPv6 soft handover extension that allows packet bicasting via two different wireless links simultaneously. However, the performance...
The development of reconfigurable and multimode terminals enable service providers to use the excess bandwidth to support services from other networks, at the expense of terminals performing vertical handover when a call is served by another network. The improvement in the performance of such an overlay heterogeneous network is expressed in terms of the increase in capacity while fulfilling each networkspsila...
In this paper applications and requirements of mobile broadband multimedia healthcare services are presented, with the focus on specific research challenges. Such pervasive multimedia healthcare applications include hospital tele-consultation, health monitoring, intelligent emergency management systems, pervasive healthcare data access, and ubiquitous mobile telemedicine. After a survey of the past...
Mobile devices that are equipped with multiple interfaces should choose the best path for each application. In this paper, we propose a new algorithm for path selection on multihomed end-hosts. The algorithm operates in two steps. The first step consists of using a MADM algorithm to allocate score to paths. These scores are then used by a bi-objective tasks assignment function which proposes a global...
Multimedia applications for mobile devices are increasing and growing more sophisticated. Many of these applications require computationally intensive processing, such as image processing, source coding, feature extraction and feature matching. If all of this processing were performed on the mobile device, its limited battery supply would quickly deplete. However, if the request must be transmitted...
Ubiquitous personal content transfer in a heterogeneous environment includes both global infrastructure based communications and local infrastructureless transfer, which leads to a hybrid networking environment. The MIP/NEMO standard can support ubiquitous content transfer, but is inefficient for local content transfer. Infrastructureless communication using ad hoc mode is often utilized by individual...
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