Service Architectures, Alternative Architectures, and Looking Ahead

Abstract

In this chapter we first examine services (Section 13.1) and service architectures (Section 13.2) in mobile wireless networks. Then in Sections 13.3 and 13.4 we consider a number of alternative network architectures, such as mobile ad hoc networks, mesh networks, sensor networks, and vehicular networks. In many application scenarios, these might be connected to, or eventually connected to, a wired network infrastructure; however, communications between nodes in these networks may traverse multiple wireless links in getting from source to destination. Moreover, significant communications between a pair of nodes in such networks may occur without any wired links in the path between the two nodes. In a traditional wireless system, on the other hand, typically only the last hop or last link is wireless, and the wired infrastructure is an essential part of the network architecture that is usually in the path of communications between any two nodes. SERVICESIn the early days of second-generation cellular systems, services and service architecture were relatively simple. The main service was voice communications. Other services included fax and text messaging. Even then there was the concept of bearer services as a distinct concept from teleservices. For example, in GSM, a teleservice is an end-to-end service, which includes the application at the endpoints, including the format and presentation of the information to the users. A bearer service, on the other hand, would be a service internal to GSM, just to bear, or transport, data from one point to another. Here we have used the words information and data in Fundamentals of Wireless Communication Engineering Technologies, First Edition. K. Daniel Wong.