Performance analysis of greedy subcarrier allocation schemes for OFDMA systems with adaptive modulation

In this paper, we propose a greedy subcarrier allocation algorithms for downlink OFDMA systems. The objective is to satisfy the rate requirement of scheduled users with the minimum system resource in term of subcarriers and feedback overhead. To reduce feedback load, we apply ordered subcarrier selection with adaptive modulation on each selected subcarriers. We consider two different options depending on whether the same modulation scheme is used on selected subcarriers or not. For the resulting scheme, we carried out through mathematical analysis and evaluated the tradeoff of performance versus complexity involved.