Hybrid smart antennas for OFDM systems-a cross-layer approach

In order to increase the bandwidth efficiency and further improve the performance of orthogonal frequency division multiplex (OFDM) systems, adaptive resource allocation and smart antennas techniques are widely applied. However, the employment of fully adaptive beamforming in physical layer for OFDM systems significantly raises the issues in medium access control (MAC) layer, hence affects the implementation of adaptive resource allocation. From a cross-layer approach, we propose a new adaptive resource allocation strategy with hybrid smart antennas for OFDM systems. By applying different smart antennas schemes according to the different quality of service (QoS) requirement of different users, the new strategy reaches a good trade-off between the complexity and the performance of OFDM systems