The Influence of Subchannel Diversity on the Performance of OFDMA Systems Based on IEEE 802.16

The performance of a mobile radio system based on OFDMA is determined by the type of mapping of logical subchannels, which are allocated for data transmissions, onto the frequency channel. The mapping scheme affects the diversity both within and between the OFDMA subchannels. This paper provides a performance comparison of different subchannel mappings from MAC point of view by means of stochastic event- driven simulations. The tradeoff between the effects of mapping subchannels onto distributed and adjacent subcarrier sets are investigated in detail. The effects are robust SNR estimation and possible throughput gains due to frequency adaptive scheduling, respectively.