This paper introduces a cooperation-based database caching system for Mobile Ad Hoc Networks (MANETs). The heart of the system is the nodes that cache submitted queries. The queries are used as indices to data cached in nodes that previously requested them. We discuss how the system is formed and how requested data is found if cached, or retrieved from the external database and then cached. Analysis is performed and expressions are derived for the different parameters, including upper and lower bounds for the number of query caching nodes as well as the average load they experience, generated network traffic, node bandwidth consumption, and other performance-related measures. Simulations with the ns-2 software were used to study the performance of the system in terms of average delay and hit ratio, and to compare it with the performance of two other caching schemes for MANETs, namely CachePath and CacheData. The results demonstrate the effectiveness of the proposed system in terms of achieved hit ratio and low delay.

In this paper, we present the design and implementation of a telecommunication system architecture that is capable of providing a new class of services for personal mobile devices such as cellular mobile phones and PDAs. The idea is to facilitate pervasive communication and information acquisition for mobile devices by taking advantage of their location and inherent Bluetooth capabilities. This includes providing free-of-charge voice and data services to the subscribers of the system. The offered services can be customized to different environments such as universities, hospitals, and companies. An example prototype implementation with specific services will be presented for the campus of the American University of Beirut.