Towards a QoS-Aware IEEE 802.16 downlink sub-frame mapping scheme

Abstract

IEEE 802.16 (WiMAX) is considered as one of the most promising wireless access technologies supporting high-capacity and long-distance communications as well as user mobility. A problem that should be addressed in the context of multi-access communications is the efficient accommodation of traffic requests to the downlink subframe. The allocation operation in downlink sub-frame is not standardized, while only restrictions on the usage of downlink sub-frame's bandwidth are defined. The most noticeable restriction is the rectangular restriction, requiring all downlink allocations to be mapped in a two-dimensions rectangular shaping. This study is a first step towards defining a QoS-aware mapping scheme, prioritizing traffic requests in accordance with the strict delay requirements they pose. The mapping scheme applies horizon scheduling, permitting bursts to be scheduled efficiently and in a simple way, following the horizons as pilots. The QoS-aware mapping scheme is evaluated by means of simulation experiments, which indicate that the proposed scheme operates effectively and efficiently, by reducing the number of unserviced users and traffic requests, and the portion of the dropped real-time traffic.