Evaluating frame structure design in WiMAX relay networks

This paper evaluates the effect of the choice of frame structure type in WiMAX networks employing non-transparent relay stations (ntRS). The IEEE 802.16j-2009 amendment allows two frame structure types, single frame and multiframe. Thus far, a comparison of the two choices, in terms of network performance, has not been made. To facilitate this evaluation, we expanded on light WiMAX ns2 add-on to support ntRS, the two-frame structure types, in addition to the relevant operational requirements (e.g. QoS support). We observed that whereas the multi-frame structure allows for higher throughput and voice capacities, the single frame shows some general advantage in terms of delay. A serious need exists, however, for schedulers that exploit the advantages of a dynamic multi-frame structure in order to realize its full potential.