Nguyen Tai Hung

mSCTP-based proxy in support of multimedia session continutity and QoS for IMS-based networks

This paper presents a new approach that supports session continuity for multimedia services in IMS-based heterogeneous environment. We propose a new component in the IMS domain, namely an proxy based on mSCTP (mobile stream control transmission protocol) that acts as an anchor point for soft vertical handover of mobile nodes, which have multiple physical interfaces (e.g., WLAN/UMTS). The mSCTP-based proxy also supports QoS provisioning and adaptation for the mobile nodes when moving in a heterogeneous wireless environment. Results show that the signaling cost for handover in our approach can be up to 23 times smaller than that in the conventional approach.

Enabling experiments for energy-efficient data center networks on OpenFlow-based platform

Energy efficiency is becoming increasingly important in todays networking infrastructure, especially in data center networks. Recent surveys have shown that the energy utilized by computing and networking components in a data center considerably contributes to its operation costs. Therefore performance and energy issues are important for the design of large multi-tier data centers that can support multiple services. However, the design, analysis, and experiments of such a large and complex system often suffer from the lack of appropriate experimental environments. With this motivation, we present a platform for in-depth analysis of energy-aware data center networks. The platform is a combination of hardware testbed and emulation. Based on real traffic patterns measured in a data center and with the energy model obtained from realistic measurements on NetFPGA-based OpenFlow switches, the experimental platform is designed to capture details of energy consumed by all network components such as links, ports, and switches under different scenarios.

QoE-aware resource provisioning and adaptation in IMS-based IPTV using OpenFlow

This article presents the architecture design and experimental evaluation of a QoE-aware flexible-QoS-control next-generation IPTV network. The architecture extends the IMS service control functionality by providing an efficient application-specific service control approach based on user satisfaction on the connectivity. The validation NGN testbed uses OpenFlow network virtualization between individual components.

Intelligent features for IMS-based IPTV

IMS has been widely recognized as the control and signaling framework for delivering of the rich communication and multimedia services to the broadband users. Amongst others, it is deployable as the service (middleware) platform for the interactive and personalized IPTV services. The goal of this paper is to provide an investigation of the advanced use cases in practical perspective. The work has been done at Hanoi University of Technology (HUT) in the scope of its initiatives for NGN research program. Major use-cases, or we called intelligent features, are the advanced electronic service guide, video on demand (VoD), (IPTV) session continuity, and parental control. Development prototypes for each of the use cases are depicted.

Toward a full implementation of SCIM functional block in IMS framework

IMS has been widely recognized as the control and brokering framework for delivering of the blended communication and multimedia services to the fix and mobile IP users. However, until recently, most of IMS services have been developed and deployed in a manner that does not carefully consider how these services can be combined and interact with each other in a beneficial way. Services can often overlap in terms of the logic that they execute, causing of redundant code across several application servers. Nowadays researching and industrial communities are approaching an IN-styled strategy of breaking down services into the basic building blocks needed to construct them known as Service Capabilities (SC). This breakdown is only possible if a full-functioning SCIM block is to be implemented. The SCIM will grant and schedule the user application to access those SCs properly, as well as resolve any rising conflict during that Service Capabilities access process. However at the moment there are no detailed specifications of this SCIM block from standardization bodies but only suggestions from research community to either put SCIM functions on Application platform or integrate it into the Service Invocation mechanisms of S-CSCF. But both of these approaches expose many disadvantages, either overloading S-CSCF or preventing the combination of services from different (Application) Platforms. In this paper, we propose a possible design that positioning the SCIM as an independent block between S-CSCF and Application Platforms. Finally a reference implementation at our Test-bed, which extended and re-used the existing IMS protocols and standard interfaces, is presented and early results are discussed.

Link Estimation and Rate Control for Optimized Video Streaming on Overlay Networks

A set of applications such as IP-TV, Internet video broadcasting, corporate telecast or E-learning require simultaneous transmission of video streaming over the Internet. However, conventional solutions for Internet streaming services have exhibited several disadvantages such as server overload and congestion in the immediate network nodes, especially in case of large number of clients. These solutions are also failed to provide QoS-guarantees for streaming services across a heterogeneous Internet. In this article, we propose a novel overlay architecture that is designed for multimedia streaming transmission on the Internet. Basic facility for overlay multicast has been introduced, which can relay a single content to multiple users with consideration of bandwidth available on the overlay links. Also, we deploy a link estimation algorithm to analyze the overlay link condition, which is exposed to congestion and interference. Based on the link estimation algorithm, we developed a rate adaptation algorithm to adapt the transmission rate to the downstream available bandwidth. Our real implementation shows that the new proposed algorithms greatly improve the perceived quality of service at the client, while better utilize network resources.

Joint Vertical Handoff and Resource Allocation in OFDMA/TDD Systems based on Software-Defined Wireless Network

One considerable challenge in future heterogeneous wireless networks (HetNet) is vertical handover. Current vertical handover approaches almost focus on resolving two questions: (1) when a Mobile Station (MS) needs to carry out a vertical handover (VHO) procedure; and (2) how a proper handover decision can be made in a HetNet environment. Actually, some approaches do not guarantee that MS can avoid handover flapping due to continuous changes in AP/BTS association. In addition, after MS joins in a new environment, many solutions do not care if VHO candidates meet requirements on QoS, such as fairness and throughput due to channel dynamicity. In this paper, we propose two algorithms: the VHO decision-making algorithm and proportional fair over HetNets (PFoHN) algorithm. VHO decision-making algorithm determines the network selection based on the availability of the target network. After VHO process is finished, resource allocation is performed by the PFoHN algorithm. In our study, the proposed approaches are developed with the support of Software-Defined Wireless Network technologies. Performance results show that PFoHN outperforms the Proportional Fair (PF) in terms of bandwidth and resource fairness, it also remarkably improves the overall system spectral efficiency.

Optimal energy allocation policy for wireless networks in the sky

Googles Project Loon [1] was launched in 2013 with the aim of providing Internet access to rural and remote areas. In the Loon network, balloons travel around the Earth and bring access points to the users who cannot connect directly to the global wired Internet. The signals from the users will be transmitted through the balloon network to the base stations connected to the Internet service provider (ISP) on Earth. The process of transmitting and receiving data consume a certain amount of energy from the balloon, while the energy on balloons cannot be supplied by stable power source or by replacing batteries frequently. Instead, the balloons can harvest energy from natural energy sources, e.g., solar energy, or from radio frequency energy by equipping with appropriate circuits. However, such kinds of energy sources are often dynamic and thus how to use this energy efficiently is the main goal of this paper. In this paper, we study the optimal energy allocation problem for the balloons such that network performance is optimized and the revenue for service providers is maximized. We first formulate the stochastic optimization problem as a Markov decision process and then apply a learning algorithm based on simulation-based method to obtain optimal policies for the balloons. Numerical results obtained by extensive simulations clearly show the efficiency and convergence of the proposed learning algorithm.

Pragmatic Correlations of Quality-of-Experience and Quality-of-Service in IMS-Based IPTV Network

To let the service system react quickly on customers’ perception or user experience while using the service, mapping functions between Quality of Experience (QoE) and Quality of Service (QoS) are strongly required in purpose of building up an intelligent QoE control system upon adjusting QoS parameters. This article studies the changing behavior of QoE with respect to changes of QoS parameters in the context of video streaming service in an IP Multimedia Subsystem-based IP Television network (IMS-based IPTV network). The article is, in fact, an extended version of the paper published by the same authors (Thu-Huong Truong, 2012). In (Thu-Huong Truong, 2012), the authors studied QoE in both terms of Mean Opinion Scores and VQM as functions of each single QoS parameter such as: loss, jitter, and delay. In this extended content, the correlation between QoE and multiple QoS parameters will be introduced. The QoE-QoS correlation could be a significant first step to build a smart QoE monitoring and control mechanism as an added value to promote the IMS-based IPTV network.

Service provisioning with Quality-of-Experience support in IMS-based IPTV

IMS-based IPTV is the next generation IPTV architecture that makes use of the advanced NGN functionalities to provide novel, interactive and blending IPTV services. It can also facilitate QoS guarantee based on the existing IMS service control capabilities. In the article, we propose a new architecture and the corresponding mechanisms to extend the service control functionalities in IMS to accommodate service guarantees based on Quality-of-Experience (QoE), that gears toward a more user-centric service satisfaction. Our architecture is deployed in a real IMS-based testbed, which allows to develop and investigate IPTV services under realistic user and network scenarios.