Evaluating frame structure design in WiMAX relay networks

SUMMARY 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.