Research On The Key Technologies Of Semantics Based NGN Adaptative Service Provisioning

Next Generation Network (NGN) is a type of network driven by services. Its evolution is directed by its capability of providing users with varieties of services according to their requirements rapidly and efficiently. Diverse user terminals and preferences, distinctive network environment and different available services on the site altogether will have impacts on the service provisioning. How to adapt the network environment, user environment and service environment to provide the user with personalized services is an important research topic in communication industry. It is of vital guiding significance and practical value in NGN development and deployment.The thesis focuses on the research on key technologies of semantics based adaptapive service provisioning, including adaptative service provisioning architecture, adaptative service discovery, adaptative service composition and adaptative service context awreness.Following the performance analysis and comparison of existing NGN architectures, an adaptive service provisioning architecture integrating SOA with semantic technique is proposed together with its typical procedures and implementation approaches. Then, considering the shortcomings of existing service discovery techniques, two improved methods are proposed. One is an adaptive service matching technique based on extended service profile to tackle the problem of lacking of adaptability to the user terminal capability. The other is a hybrid semantic matching algorithm integrating semantic matching with lexical similarity matching. It tackles the problem that the existing algorithms are unable to distinguish those services with identical I/O parameters but with different functionalities. Furthermore, considering the fact that the existing service composition algorithms cannot support the automatic composition of telecom services and web services due to the absence of semantic description in WSDL, an automatic service composition and validation method is proposed. It extends CSTA service profile with OWL-S and can be used to realize the automatic composition and validation of NGN converged services. Finally, a mechanism is proposed to acquire network real-time environment parameters by reusing SIP, the NGN dominant control protocol. A semantics based context-aware SIP proxy server is developed and two adaptive services are designed to validate its capability adaptable to the change of network and service environment.Detailed simulation is conducted to verify the proposed architectural models and algorithms. The simulation results have shown that their performance is superior to existing ones and can meet the requirements of provisioning personalized services adaptable to user, network and service environments. They are of good reference value to the realization and evolution of NGN service provisioning technologies.