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This paper develops a generalized channel-aware power control scheme to enhance the multi-packet reception (MPR) capability for random access. In the proposed scheme, each user randomly selects its transmit power with a probability in accordance with a distribution function based on its own channel state. For two-user systems, we show that the optimal power distribution function has a simple discrete...
In cellular mobile communication systems, the co- channel inter-cell interference (ICI) remains as a critical barrier to achieving further improvement in spectrum efficiency. As an approach to controlling downlink ICI, multi-cell coordinated MU-MIMO has been actively discussed in many papers. In multi-cell coordinated MU-MIMO, the simultaneous transmission for multiple mobile stations is made possible...
Device-to-Device (D2D) communication has drawn great interest in academia and industries due to the extended network coverage and reduction of the restrictions of traditional cellular systems. On the other hand, a new paradigm called content-centric networking (CCN) has been proposed for scalable, flexible, and secure services in the future networks. With CCN, it is possible to increase the throughput...
This paper is devoted to analysis of QoS parameters of WebRTC traffic presented for centralized videoconferencing system used for collaborative work. This system consists of a videoconference application, built according to the WebRTC architecture, and a telemetric system, built as the IoT environment. Tests were carried out for three locations of the conference bridge: in private cloud (the OpenStack...
The increasing number of mobile devices with high processing power and high-resolution screens had led to an enormous growth of mobile video traffic. Mobile network operators face the requirement to efficiently support large numbers of concurrent unicast streaming sessions. In the present work, the long-term quality of experience perceived by the user, the fairness, and the overall system efficiency...
The objective of this paper is to compare uplink (UL) performance with different antenna technologies when receiving Non-Line of Sight (NLOS) signal in field tests. The antenna configurations in use were a passive antenna system and an active antenna system (AAS). The radiation pattern can be controlled horizontally by changing its azimuth angle and vertically by changing the tilt angle of the antenna...
Mobile web traffic and application data demands are growing at a rapid rate and are at odds with resource-constrained, data-capped, wireless mobile devices. Data compression can be used to reduce web traffic, save energy, and make network transfers faster. Compression can, however, hurt performance if not used judiciously. We propose Locomotive, a library that improves the performance of network transfers...
Upload and download traffic often coexist in mobile networks. However, TCP download throughput could be substantially degraded by upload traffic even if the downlink is not the bottleneck. Previous works such as RSFC and TCP-RRE can substantially improve TCP download throughput in the presence of concurrent TCP upload flows, albeit at the expense of significantly degraded upload throughput performance...
We consider the practical problem of video surveillance in public transport systems, where security videos are stored onboard, and a central operator occasionally needs to access portions of the recordings. When this happens, the selected video must be uploaded within a deadline, possibly using multiple parallel wireless interfaces. Interfaces have different associated costs, related to tariffs charged...
Growing mobile data usage has led to end users paying substantial data costs, while Internet service providers (ISPs) struggle to upgrade their networks to keep up with demand and maintain high quality-of-service (QoS). This problem is particularly severe for smaller ISPs with less capital. Instead of simply upgrading their network infrastructure, ISPs can pool their networks to provide a good QoS...
In order to cope with the exponential growth of mobile traffic, mobile operators need to access more spectrum resources. LTE in unlicensed spectrum (LTE-U) has been proposed to extend the usual operation of LTE in licensed spectrum to cover also unlicensed spectrum. However, this extension poses significant challenges especially regarding the coexistence between LTE-U and legacy systems like Wi-Fi...
HTTP adaptive streaming (HAS) is the dominating type of video traffic in fixed and mobile networks. Although more and more mobile users stream videos over their cellular data connections, buffering is still a common problem due to fluctuating radio signal strength. We will demonstrate a new generation of context-aware HAS algorithms, which adapt video bit-rate based on location and radio information...
In mobile networks, users may lose coverage when entering a building due to the high signal attenuation at windows and walls. Under such conditions, services with minimum bit-rate requirements, such as video streaming, often show poor Quality-of-Experience (QoE). We will approach this problem in two steps. First, we present a Bayesian detector that combines measurements from two Smartphone sensors...
To cope with increasing mobile data traffic, researchers are currently working on traffic offloading techniques for delivering data over unlicensed cellular bands. Current offloading schemes based on offloading data to Wi-Fi regardless Wi-Fi has sufficient throughput or not. Though, we propose a novel offloading technique based on the Remaining Throughput Scheme (RTS) for Wi-Fi selection. In our proposed...
Users located on the cell edge suffer from low data rates due to interference and poor reception. The Coordinated Multipoint technology targets this problem but it imposes overhead on the network, which can result in degradation of the Quality of Service. The Direct CSI feedback to Elected Coordination station architecture minimizes such overhead, resulting in improved data rates. Here, we analyze...
Millimeter-wave (mm-wave) communication is a promising technology for supporting extremely high data rates in the next generation wireless networks. Mm-wave signals experience high path loss and directional transmission is required to compensate the severe channel attenuation. The special characteristics of the mm-wave propagation arise opportunities as well as challenges for the network resource...
As video accounts for larger wireless traffic, improving users' quality of experience becomes important for network service providers. In this paper, we apply supervised machine learning technique to predict one objective QoE metric, video starvation, with the users' features, recorded at the beginning of each video session. We show that static users and adaptive streaming users have less starvation...
The measurement of quality and efficiency of a wireless Wi-Fi network is particularly difficult, as there is not a single tool that can record measurements from all sides of the system, i.e. from both the access point and the end-user. Existing tools are able to monitor the overall quality of the wireless network; although they cannot determine how end-users experience the quality of Wi-Fi in a particular...
Recent development of wireless communication systems and standards is characterized by constant increase of allocated spectrum resources. Since lower frequency ranges cannot provide sufficient amount of bandwidth, new bands are allocated at higher frequencies, for which operators might resort to deploy more base stations to ensure the same coverage. Connecting increased number of base stations to...
The effort to extend cellular technologies to unlicensed spectrum has been gaining high momentum. Listen-before-talk (LBT) is enforced in the regions such as European Union and Japan to harmonize coexistence of cellular and incumbent systems in unlicensed spectrum. In this paper, we study throughput optimal LBT transmission strategy for load based equipment (LBE). We find that the optimal rule is...
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