Weak Interactive Systems Design in Wireless Broadcast Channels

Abstract

Massive informations transmission in wireless broadcast channels has many well-known problems. This is an asymmetric environment where broadcasting the information is an effective and good way to make the information available simultaneously to a large number of users, however the optimization of the bandwidth allocation implies more attention. Moreover we have to make point of the limited battery capacity of mobile devices. In this paper we will present some solutions making use of weak interactivity, that is useful in case of possible low bandwidth and permits a minimization in communication channel utilization. Informations selections are done on the device itself. In a second phase we will deal with informations and their organization in indexed structures: this is important when using devices with limited memory and a low processing capability. During last years we attended at a rapid development and at a following diffusion of wireless-communication technology, that is causing a convergence between high- speed wireless networks and personal mobile devices. Mobile computing is the result and in near future a massive number of mobile users will access a great variety of informations at any time from everywhere, with their portable devices that are frequently low power-battery. In mobile environments data are disseminated by a base station or a satellite to mobile clients through wireless channels and data broadcast is an actractive solution in this context. In fact the bandwidth resource is limited and broadcast allows these massive accesses from clients to the data and is preferable to point-to-point delivery. In addition most wireless systems are asymmetric: the downlink, from the base station to the client, has a much higher communication capacity than the uplink in the opposite direction. In push-based broadcast data are disseminated proactively and repeatedly while clients passively listen to the channel, filter data and pick only the ones they need, so the load on the uplink channel decreases.