Scheduling Real-Time Data Items In Multiple Channels And Multiple Receivers Environments

Previous researches on broadcast scheduling assume that once a client generates a request, this request will not be discarded until it is satisfied. However, if a client needs the traffic information to decide which road to drive, he must receive the response before he reaches the crossroad. Some recent works begin to address the transmission of the real-time database. The pinwheel scheduling problem trying to schedule the real-time database was first introduced in [3]. This problem is generalized in [2] which can be applied to generate the fault-tolerant broadcast disks. Moreover, an adaptive hybrid transmission technique based on the PinOpt [2] algorithm is presented in [1] and [5]. In this paper, the problem of transmitting data items with timing constraint in the multiple broadcast channels where the clients equip with multiple receivers is studied. In our approach, the data items are divided into two sets, the broadcast data set and the on-demand data set. The data items in the broadcast data set is periodically broadcast on the broadcast channels while the data items in the on-demand data set are transmitted when they are requested. The server offline allocates the data items in the broadcast data set on the multiple broadcast channels. The clients retrieved data items from the broadcast channels are guaranteed to receive them within the timing constraint. Once the desired data item is not included in the broadcast channels, clients make requests associated with deadlines to the server. By using the bandwidth remaining for the on-demand mode, the server broadcasts the requested data items in an online fashion. The intention of our work is to serve as many requests as possible.