Jun-Zhao Sun

Features in future: 4G visions from a technical perspective

Mobile communication is continuing to be one of the hottest areas developing at a booming speed, with advanced techniques emerging in all the fields of mobile and wireless communications. Currently, 3G mobile communication systems are just beginning to be deployed, while research on the next generation of mobile communications, 4G wireless and mobile networks, begin to pave the way for the future. This paper studies the visions of 4G from a technical perspective. After a brief review on the development history and status of mobile communications and related 4G perspectives, we present an overall 4G feature framework based on the kernel concept of integration, in which two key features (diversity and adaptability) of the three targets (terminals, networks and applications) are described in detail. The concepts of both external and internal diversity of each target are defined to illustrate the causes and solutions of the adaptability feature. Then, along the entire 4G domain, each feature in the framework is deeply discussed from a technical standpoint, in which promising techniques and possible research issues for sufficient support of adaptability are also proposed. Finally, a short summary on 4G visions is presented as a continuum of features in the development of the mobile communications world.

Mobility and mobility management: a conceptual framework

The tremendous demands from the social market are pushing the development of mobile communications faster than ever before, leading to the emergence of many new techniques. Within those techniques, mobility management has widely been recognized as one of the most important problems for seamless access to wireless networks and services. This paper proposes a conceptual framework for mobility and mobility management, with the emphasis on the key research issues involved in the effort to design graceful mobility management schemes. The effects of mobility on both the architectures and protocols of networks and communications are presented. Diversity of the future mobile communication systems introduces new challenges, which lead to the definitions of mobility on various levels according to different granularities. Mobility management is defined as two complementary operations, i.e. location management and handoff management. The paper also describes mobility management issues at the network layer. The processing stages of the two operations are introduced, together with the analyses of key research issues and possible solutions. Finally, we discuss issues concerning the performance evaluation of mobility management schemes.

Context-aware pervasive service composition and its implementation

Incorporating service composition and pervasive computing into managing users’ complex everyday activities calls for the Pervasive Service Composition paradigm for everyday life. In this paper, we propose the concept of Context-Aware Pervasive Service Composition (CAPSC), which aims at enabling a pervasive system to provide user service compositions that are relevant to the situation at hand. We investigate CAPSC requirements and design a CAPSC architecture by taking into account context-aware peer coordination, context-aware process service adaptation, and context-aware utility service adaptation. We present a proof of concept application prototype as well.

Towards connectivity management adaptability: context awareness in policy representation and end-to-end evaluation algorithm

An infrastructure based on multiple heterogeneous access networks is one of the leading enablers for the emerging pervasive and ubiquitous computing paradigm, in which the optimal management of diverse networking resources is a challenging problem. This paper presents a context-aware policy mechanism and related end-to-end evaluation algorithm for adaptive connectivity management of multi-access wireless networks. A policy is used to express the criteria for adaptive selection of the best local and remote network interfaces. The best connection can then be used for the establishment of a channel as well as the maintenance of on-going data transmission. Rich context information is considered in the policy representation with respect to user profile and preference, application characteristics, device capability, and network QoS condition. The decision of the best access networks to be used is made on the basis of an end-to-end evaluation process. The decision can be made in both Master-Slave and Peer-to-Peer modes. The paper focuses on the methods for policy representation and connection evaluation algorithm. A case study is presented to show the usability of the proposed policy mechanism and decision-making algorithm in the adaptive management of heterogeneous networking resources.

Towards a conceptual model for context-aware adaptive services

Recent advances in both portable devices and wireless networks make mobile computing a reality. Embedded and invisible computing resources are paving the way to a new paradigm known as pervasive computing. More attention needs to be paid to the development of intelligent services in such a highly dynamic environment. We aim to present a conceptual model for context awareness based service adaptation methodology. We describe context in context space and represent it with 4-tuple. We then discuss context awareness in terms of both context organization and utilization. Finally, we introduce the notion of adaptation and present the framework for context-aware adaptive services.

CME: a middleware architecture for network-aware adaptive applications

Network QoS parameters experience great fluctuations during the execution of network applications. Especially in mobile and pervasive computing environments the variation becomes more serious. Applications need to adapt their functions to the changing network status. Moreover, an enhanced software platform is necessary to provide adaptive network management services to upper software components. This paper proposes CME, a middleware architecture for service adaptation based on network awareness. CME is structured as the software platform both to provide network awareness to applications and to manage network resources in an adaptive fashion. The overall architecture of CME framework is descried. Core components include connection monitor, policy manager and connection controller. Adaptation mechanisms are introduced in detail.

Adaptive connectivity management middleware for heterogeneous wireless networks

The trends of network convergence and mobile accessibility in the Internet are bringing new challenges to the connectivity management of end hosts. Concerning network convergence, the configuration of heterogeneous access networks should be taken into consideration. As for mobile accessibility, seamless handoff between diverse access points is a challenging issue. This article presents the design and implementation of connectivity management middleware (CMM), a channel-based architecture for context-aware connectivity management. This architecture can both provide network awareness to applications and manage network resources in an adaptive fashion. In the case of network awareness, the platform provides interfaces for applications to query network QoS and availability status, as well as subscribe connection events. As for adaptive resource management, channel-based transport services for seamless access switching and disconnection treatment are provided based on a policy mechanism. A prototype is implemented with which experiments were performed in a GPRS-WLAN integrated environment in order to demonstrate the operational correctness of the architecture. Performance metrics are measured and analyzed.

Pervasive Social Computing: augmenting five facets of human intelligence

Pervasive Social Computing is a novel collective paradigm, derived from pervasive computing, social media, social networking, social signal processing, etc. This paper reviews Pervasive Social Computing as an integrated computing environment, which promises to augment five facets of human intelligence: physical environment awareness, behavior awareness, community awareness, interaction awareness, and content awareness. Reviews of related studies are given, and their generic architectures are designed. The resulting architecture for Pervasive Social Computing is presented. A prototype is developed and examined, in order to investigate the characteristics exhibited by Pervasive Social Computing.

Application of connectivity information for context interpretation and derivation

Ubiquitous computing is the emerging new computing paradigm, of which context awareness is a key feature. In this paradigm connectivity is more than transport resource, but an important context source that can be utilized in many ways. This paper studies connectivity from the viewpoint of context awareness. Architecture for connectivity context management is proposed. Raw connectivity context including device, network, and end-end context is thoroughly defined. Methods for the derivation of high-level connectivity context are presented. The derivation is through the intelligent interpretation of raw connectivity context with the combination of other contextual information, in which knowledge-based rules are adopted. Connectivity context can also be used in the generation of other context information, in which connectivity context is employed in forms of one input factor. This paper studies three typical cases of connectivity based context derivation: location, application, and user related context.

On fundamental concept of mobility for mobile communications

The tremendous demands from the social market are pushing the booming development of mobile communications faster than ever before, leading to the emergence of many new advanced techniques. Mobile communications are changing life styles in many ways. Behind the scenario, the outstanding characteristic that makes this reality is mobility. The paper studies the basic concepts of mobility for mobile communications, with an attempt to answer the fundamental questions on mobility. A conceptual discussion is made on mobility in the contexts of both computation and communication leading to the illustration of mobile computing. The effects of mobility on both architectures and protocols of networks and communications are analysed. The concept and operations of mobility management for mobile communications are also introduced. New challenges arise in future mobile communications systems with diversity as the key feature, which lead to the classification of mobility according to different granularities.