In a wireless communication environment, data broadcasting allows simultaneous access of data by an arbitrary number of clients while on-demand data delivery service provides instant access to data items. Therefore, complementing the use of broadcast and on-demand data delivery services can be an economic way to build a highly scalable wireless information system with limited bandwidth. The use of data broadcasting should be adaptive, such that system response time can always be minimised. A traditional approach requires the development of a system response time equation, based on which, the optimal solution can be found. However, obtaining such an equation is not always possible. We have observed that by maintaining a certain level of on-demand channel utilization, a close approximatio...[ Read more ]

In a wireless communication environment, data broadcasting allows simultaneous access of data by an arbitrary number of clients while on-demand data delivery service provides instant access to data items. Therefore, complementing the use of broadcast and on-demand data delivery services can be an economic way to build a highly scalable wireless information system with limited bandwidth. The use of data broadcasting should be adaptive, such that system response time can always be minimised. A traditional approach requires the development of a system response time equation, based on which, the optimal solution can be found. However, obtaining such an equation is not always possible. We have observed that by maintaining a certain level of on-demand channel utilization, a close approximation to the optimal solution can be obtained. Using this approach, a real-time adaptive data delivery algorithm is developed. Our algorithm does not require the access information of the data items to be known exactly, which is needed normally for this kind of optimization problems. A simple and low overhead bit vector mechanism is able to capture the relative popularities of the data items. With this information, our algorithm can give a performance comparable to the ideal case in which the access information for each data item is known exactly.