Gabriel-Miro Muntean

Utility-based Intelligent Network Selection in Beyond 3G Systems

Development in wireless access technologies and multihomed personal user devices is driving the way towards a heterogeneous wireless access network environment. Success in this arena will be reliant on the ability to offer an enhanced user experience. Users will plan to take advantage of the competition and always connect to the network which can best service their preferences for the current application. They will rely on intelligent network selection decision strategies to aid them in their choice. The contribution of this paper is to propose an intelligent utility-based strategy for network selection in this multi-access network scenario. A number of utility functions are examined which explore different user attitudes to risk for money and delay preferences related to their current application. For example we show that risk takers who are willing to pay more money get a better service.

CMT-QA: Quality-Aware Adaptive Concurrent Multipath Data Transfer in Heterogeneous Wireless Networks

Mobile devices equipped with multiple network interfaces can increase their throughput by making use of parallel transmissions over multiple paths and bandwidth aggregation, enabled by the stream control transport protocol (SCTP). However, the different bandwidth and delay of the multiple paths will determine data to be received out of order and in the absence of related mechanisms to correct this, serious application-level performance degradations will occur. This paper proposes a novel quality-aware adaptive concurrent multipath transfer solution (CMT-QA) that utilizes SCTP for FTP-like data transmission and real-time video delivery in wireless heterogeneous networks. CMT-QA monitors and analyses regularly each paths data handling capability and makes data delivery adaptation decisions to select the qualified paths for concurrent data transfer. CMT-QA includes a series of mechanisms to distribute data chunks over multiple paths intelligently and control the data traffic rate of each path independently. CMT-QAs goal is to mitigate the out-of-order data reception by reducing the reordering delay and unnecessary fast retransmissions. CMT-QA can effectively differentiate between different types of packet loss to avoid unreasonable congestion window adjustments for retransmissions. Simulations show how CMT-QA outperforms existing solutions in terms of performance and quality of service.

Game Theory-Based Network Selection: Solutions and Challenges

In order to cater for the overwhelming growth in bandwidth demand from mobile Internet users operators have started to deploy different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to enable network selection mechanisms in order to keep the mobile users Always Best Connected (ABC) anywhere and anytime. Game theory techniques have been receiving growing attention in recent years as they can be adopted in order to model and understand competitive and cooperative scenarios between rational decision makers. This paper presents an overview of the network selection decision problem and challenges, a comprehensive classification of related game theoretic approaches and a discussion on the application of game theory to the network selection problem faced by the next generation of 4G wireless networks.

Energy consumption analysis of video streaming to Android mobile devices

Energy conservation has become a critical issue around the world. In smart phones, battery power capabilities are not keeping up with the advances in other technologies (e.g., processing and memory) and are rapidly becoming a concern, especially in view of the growth in usage of energy-hungry mobile multimedia streaming. The deficiency in battery power and the need for reduced energy consumption provides motivation for researchers to develop energy efficient techniques in order to manage the power consumption in next-generation wireless networks. As there is little analysis in the literature on the relationship between the wireless environment and the mobile device energy consumption, this paper investigates the impact of network-related factors (e.g., network load and signal quality level) on the power consumption of the mobile device in the context of video delivery. This paper analyzes the energy consumption of an Android device and the efficiency of the system in several scenarios while performing video delivery (over UDP or TCP) on an IEEE 802.11g network. The results show that the network load and the signal quality level have a combined significant impact on the energy consumption. This analysis can be further used when proposing energy efficient adaptive multimedia and handover mechanisms.

A new adaptive multimedia streaming system for all-IP multi-service networks

A significant challenge in all-IP multi-service networks is to balance the goal of providing high-quality services to the end-users with the desire to maximize the number of end-users that can be simultaneously served. This paper presents a solution to this challenge by using the Quality-Oriented Adaptation Scheme (QOAS) for delivering multimedia streams. This adaptive mechanism uses feedback from clients regarding the quality of delivery to assist the server in making dynamic adjustments to the transmitted streams. Experimental objective and subjective test results illustrate the significant performance improvements achieved by QOAS, both in terms of number of simultaneous viewers served and of end-user perceived quality.

Adaptive Energy Optimization in Multimedia-Centric Wireless Devices: A Survey

Over the last couple of years, there has been an exponential increase in the number of applications accessible from various mobile handsets, including Facebook, Twitter, YouTube, etc. In particular, rich media service distribution among smart-phones and other handheld devices is becoming increasingly popular among users. In fact, the next generation wireless technologies have put significant emphasis on supporting distribution of rich media content and video-on-demand services. However, energy consumption in the handheld wireless devices is a major bottleneck that hinders the growth of mobile device based rich media services. The biggest problem today in the mobile world is that the mobile devices are battery driven and the battery technologies are not matching the required energy demand. This paper outlines the major energy-consuming components in handheld devices like smart-phones, PDAs and other multimedia-centric wireless devices. Further, this paper surveys different research works on how the energy consumption could be optimized and provides detailed discussions on the latest energy saving techniques in the major components of the mobile devices. In addition, the paper surveys other systemic energy optimization techniques so that the overall battery life of the device is increased. Major global research projects and their research focus are then surveyed. Finally, a brief summary is provided along with some open research problems and different possible future research directions.

Performance-Aware Replication of Distributed Pre-Recorded IPTV Content

Video recording in IPTV systems is a promising service that provides time-shifted services in relation to storing TV content closer to user devices such as set-top boxes. Existing approaches do not support collaboration between nodes which have correlated contents, a fact that can affect the performance of the overall system. To make this service more interactive and proactive, this paper presents the architecture using the smart personal information network (Smart PIN) as a novel performance-based content sharing network for IPTV content which uses a user-centric utility-based multimedia data replication scheme (MDRS). This allows the exchange of data based on both network performance and user interest in exchanged multimedia content in order to achieve efficient content sharing. The proposed solution is evaluated through extensive simulations and results show much improved behavior in comparison with two other existing general purpose data replication schemes.

A vehicle route management solution enabled by Wireless Vehicular Networks

Traffic congestion is a very serious problem which is growing worse as the number of cars on the road continues to increase, out-pacing the provision of road capacity. This paper presents a novel vehicle routing algorithm for TraffCon - an innovative traffic management system for wireless vehicular networks. The algorithm tackles the traffic congestion problem by seeking to optimize the usage of the existing road capacity, reduce vehicle trip times and decrease fuel consumption and the consequent gas emissions. Results demonstrate that the algorithm significantly reduces congestion, journey times and fuel consumption and emissions in comparison with an existing approach.

Performance Evaluation of Multimedia Content Distribution Over Multi-Homed Wireless Networks

The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabilities of mobile devices is creating opportunities for multimedia distribution. Through its multi-homing feature, the ability to support multiple network connections in a single end to end association, the transport layer Stream Control Transmission Protocol (SCTP) can enable seamless and transparent communication sessions over multiple heterogeneous networks. This paper analyzes the performance of multimedia distribution when making use of two multi-homing SCTP-based approaches: Single Path Transfer and Concurrent Multi-path Transfer, in which a single or all paths within an association are used simultaneously for data transmission. In this investigation various retransmission policies and different parameter sets are used in turn and recommendations are made for achieving best results during video delivery. In order to perform this study a novel realistic evaluation tool-set was proposed and is described, which can simulate video delivery over SCTP. Our simulation results and analysis show how to optimize the transmission of multimedia content over SCTP associations in both single and multipath scenarios.

Subjective Assessment of Region of Interest-Aware Adaptive Multimedia Streaming Quality

Adaptive multimedia streaming relies on adjusting the video contents bit-rate meet network conditions in the quest to reduce packet loss and resulting video quality degradations. Current multimedia adaptation schemes uniformly adjust the compression over the entire image area. However, research has shown that user attention is focused mostly on certain image areas, denoted areas of maximum user interest (AMUI), and their interest decreases with the increase in distance to the AMUI. The region of interest-based adaptive multimedia streaming scheme (ROIAS) is introduced to perform bit-rate adaptation to network conditions by adjusting video quality relative to the AMUI location. This paper also extends ROIAS to support multiple areas of maximum user interest within the same video frame. This paper presents the performance analysis of ROIAS in terms of the impact on user perceived video quality measured using subjective video quality assessment techniques based on human subjects. The tests use a wide range of video clips, which differ in terms of spatial and temporal complexity and region of interest location and variation. A comparative evaluation of both subjective and objective video quality test results is performed and demonstrate the benefit of using ROIAS for adaptive video quality delivery.