Beam selection algorithm based on PTR metric and its synchronization performance

A switched-beam beamformer is combined with a multi-receiver architecture to improve the signal-to-interference-and-noise-ratio (SINR) for indoor wireless LANs. The multiple selected beams can be used for diversity combining and for multiple-input multiple-output (MIMO) links. The beam selection controller uses two metrics, the received signal strength indication (RSSI) and the peak-to-trough ratio (PTR), to interactively select beams with good SINR. The second metric prevents beam falsing. This paper will describe the receiver system and the associated beam selection algorithm, and present the relationship between the PTR and SINR. The paper also shows that the beam selection algorithm based on the PTR is robust to synchronization offsets for 802.11a and 802.16 waveforms.