Joint beamforming and channel selection for multicast IEEE 802.11n WLANs

Multicast transmission over WLANs is becoming a popular application. IEEE 802.11n technology is developed due to the ever increasing demand for higher data rate and quality of service (QoS). However, there is an unmanaged and rapid growth of wireless devices in unlicensed frequency bands. WLANs experience significant interference from near-by environment which lead to significant performance degradation. The impetus of the present study is to describe a novel distributed algorithm that will allow interfering access points (APs) to select appropriately the channel band that will experience minimal interference. Therefore, a fair share of available spectrum is achieved. We investigate the IEEE 802.11n WLAN where a large number of clients attempt the same high bit rate from the single AP. We formulate the problem of transmit beamforming to a multicast group and minimize total emitted power adopting a QoS criterion.