Cross-Layer Design for Data Burst Construction in the Downlink of IEEE 802.16 Systems

In this paper we consider the problem of allocating resources to users in the downlink of a 802.16 network. This network uses orthogonal frequency-division multiple access (OFDMA) as the downlink transmission technology. The transmission resources available in the downlink include bandwidth (subcarriers), time (OFDMA symbols) and transmission power all of which are limited. The frequency-time resource allocations for each user must satisfy certain constraints (e.g., must form logical rectangular bursts). The focus of this paper is on the determination of the size and locations of these bursts within the frame for the given scheduler decisions. Prior work has addressed this problem independently of other protocol layers. In our approach we simplify the burst construction problem, without significant performance degradation, by taking into account higher layer information such as the tolerable delay of the underlying application.