Broadcast Data Delivery in Mobile Computing

摘要

In traditional client/server systems, data are delivered on demand. A client explicitly requests data items from the server. This form of data delivery is called pull-based. In an increasingly important class of networked environments such as in wireless networks with mobile clients, cable and direct satellite broadcast networks, communication is asymmetric. This facility provides the infrastructure for a new form of data delivery called push-based delivery by means of broadcasting. This form of data delivery is important in the wireless networks, as it scales well to an arbitrary number of users. In push-based data delivery, the server repetitively broadcasts data to a client population without a specific request. Clients monitor the broadcast and retrieve the data items they need as they arrive on the broadcast channel. Push-based delivery is important for a wide range of applications that involve dissemination of information to a large number of clients. Issues that arise in broadcast data delivery model and ways to deal with them are different from traditional client/server model. In this paper, we discuss issues that arise in broadcast data delivery model and overview some strategies to tackle them. Wireless broadcast is an important technique for disseminating data to mobile users, because it scales to an arbitrary number of users.