traffic scheduling for frame length minimization in ofdma based systems
In this paper, we investigate a scheduling problem in systems adopting OFDMA transmission technique at the physical layer, like WiMAX (IEEE 802.16) systems. In such systems, carriers with different rates must be assigned to users, each carrier being assigned to one user at most, each user can be scheduled on multiple carriers. The objective of our problem is to produce a legal schedule (i.e. one meeting all the system constraints) with minimum length. We first show that the above problem is NP-complete, and thus computationally intractable, even in an extremely simple case. Then, we propose several very simple and fast suboptimal heuristics, and evaluate their average performance by means of simulation experiments. Some of the proposed heuristics perform very well, being in most cases within 10\% of the optimal (minimal) schedule length.
traffic scheduling wimax heuristic algorithms ofdma wireless systems complexity