Low-Complexity Beamforming Techniques for IEEE 802.11n WLANs

The impetus of the present study is to describe a downlink beamforming method that increase spectrum efficiency and significantly reduces implementation complexity and power consumption compare to beamforming technique at each sub-carrier, proposed in the ongoing IEEE 802.11n standardization. In our scheme, common transmission weight vectors are used at a set of users in all sub-carriers. Our strategy consists of simultaneously designing downlink beamformers to multiple co-channel sets of users under the constraint on providing at least a prescribed received Signal-to-Interference - plus - Noise Ratio (SINR) to each intended receiver. We assume that the instantaneous channel gains are known at the Access Point (AP) for all users. Simulation results show substantial gain for our proposed algorithms in IEEE 802.11n wireless access networks.