A heuristic algorithm for optimum transmission schedule in broadcast packet radio networks

Packet Radio networks are to provide data communications among a set of nodes distributed over a wide region. Transmission from nodes is broadcast in nature. Where direct communication between two nodes is not possible, connection is established in multiple hops. A time division multiple access (TDMA) protocol is adopted for conflict free communication among different nodes. The goal is to find a conflict free transmission schedule for different nodes at different time-slots of a fixed length time frame, called TDMA cycle. The optimization criterion is primarily to (1) minimize the TDMA cycle length, and then to (2) maximize the number of transmissions. The problem is proved to be NP-complete. A randomized algorithm is proposed, which is very efficient to achieve the first optimization criterion. The results are shown to be superior compared to other recently reported competitive algorithms.