EIRP-restricted downlink beamforming in WLAN OFDM systems
01 January 2006
Downlink beamforming for a wireless local area network (WLAN) employing orthogonal frequency-division multiplexing (OFDM) system is addressed, where an access point (AP) is equipped with multiple antennas and a terminal uses a single antenna.
A joint optimization problem for the beamforming weights over all the sub-carriers subject to the equivalent isotropic radiated power (EIRP) constraint is formulated and two sub-optimal solutions are compared in terms of their performance and complexity in a typical IEEE 802.11 environment.
It is shown that the proposed beamformer based on non-adjacent sub-carrier grouping demonstrates much better trade off between performance and complexity compared to the conventional simplification approach based on highly correlated sub-carrier grouping.