A Novel Dynamic Fuzzy Analysis Hierarchy Model Enabling Context-Aware Service Selection in IMS for Future Next-Generation Networks

3GPP has standardized IP multimedia subsystem (IMS) as the solution for multimedia service delivery based on Internet for future next-generation networks (NGNs) and it aims to merge Internet and wireless cellular networks together in order to enable rich multimedia services. The home subscriber server (HSS) is a crucial entity in IMS, which provides the functions such as access authentication and authorization as well as service data management in GPRS and CS domain. However, it still cannot provide the automatic service selection to help the users access application servers according to their demands and contexts. This paper proposes a novel context-aware service selection approach which helps perform service selection according to individual user's contexts such as the preferences and habits. This approach includes two main components which are set in HSS. One is context management and the other is selection engine, which employs the dynamic fuzzy analysis hierarchy model (DFAHM) to conduct service selection according to the contexts. Based on the quantified dynamic and fuzzy evaluation, the DFAHM helps select the most suitable services for the users. And, the model evaluation is presented to verify the feasibility of DFAHM. The results show that the DFAHM helps achieve service selection according to the users' contexts.

I. Introduction

3GPP has standardized IP Multimedia Subsystem (IMS) architecture as a solution for multimedia service delivery based on Internet [1] for future next-generation networks (NGNs) [2], [3], [8]. Its aim is to merge Internet and cellular worlds together in order to enable rich multimedia services. The Home Subscriber Server (HSS) is a crucial entity that connects the Application Server (AS) with the Serving-Call Session Control Function (S-CSCF) in IMS. 3GPP HSS contains the functions known as access authentication and authorization and overall subscription handling as well as service data management [1]. However, due to the rapid popularity of wireless networks and the prevalence of Web 2.0, HSS is challenged by a problem that how to help S-CSCF access the user's most demanded web services from the numerous ones. And, the service selection acts an important role to select the most suitable services for the users. Therefore, the Service Authorization Support (SAS), which not only provides basic authorization for MT call/session establishment and service invocation, but also updates the appropriate serving entities with the relevant information related to the services provided to the user, should make more efforts to support service selection. Unfortunately, few works were conducted on this problem. Any information used to characterize the situation of an entity or anything having impacts on the behavior of an entity is considered as the context [4]. So, it is feasible and reasonable to utilize the context-awareness to implement service selection in HSS to facilitate the service filter.