Link-adaptation-enhanced dynamic channel allocation for MIMO-OFDM wireless networks

We propose a link-adaptation (LA)-based system infrastructure and develop the corresponding dynamic channel allocation (DCA) algorithm for downlink data transmissions over MIMO-OFDM wireless networks. By integrating a set of LA techniques, our system can dynamically select transmit antennas, modulation levels, and transmission power for different mobile users. Jointing with the proposed system infrastructure, we develop the DCA algorithm to maximize the total system throughput. In designing the DCA algorithm, we first focus on CDMA-based MIMO-OFDM systems with any given spreading gain G. Deriving the optimal G to achieve the maximum throughput, we prove that the optimal spreading gain is G = 1. This implies that the system without using spread spectrum (SS) is optimal in terms of maximizing the throughput. Extensive simulations show that the system throughput increases significantly with the numbers of transmit antennas, receive antennas, and mobile users. Moreover, our DCA algorithm can significantly improve the system throughput performance as compared with the conventional fixed channel allocations (FCA).