Fair Broadcasting Schedules on Dependent Data in Wireless Environments

In wireless mobile services, data broadcasting provides an effective method to disseminate information to mobile clients. In some applications, the access pattern of all data items can be represented by a weighted DAG. In this paper, we explore how to generate the data broadcast schedule for dependent data, which can be modeled as a weighted DAG, to serve all the mobile clients effectively and fairly. The resulting data broadcast schedules must keep the original dependency and minimizes the variance of latency. We prove that it is NP-complete to find such an optimal solution. Due to the NP-completeness, we provide two heuristics to solve the problem. In additions, we discuss the upper and lower bounds on the variance of latency for the problem.