Multiuser MIMO-OFDMA with Different QoS Using a Prioritized Channel Adaptive Technique

In this paper, an orthogonal multiple access scheme is considered for different users with different quality of ser- vice (QoS) requirements. Therefore, the users are multiplexed using orthogonal frequency division multiple access (OFDMA) transmission. A multiple-input multiple-output (MIMO) antenna system is considered between the base-station (BS) and the existing mobile sets (MSs). In order to realize different QoS, the transmission bit-rates and powers are adapted to the various channel conditions with different margin separations. In here, we proposed two different subcarrier sorting schemes in order to exploit the multiuser diversity and to enhance the performance in case of channel uncertainties. Accordingly, our simulations examine the performance of the downlink (broadcast) channel adaptation for different channel conditions assuming a single cell scenario. Index Terms—MIMO, OFDMA, adaptive modulation, power allocation, limited feedback, QoS, multiuser diversity