er interference or increase range. several spatial channels. Antenna 2 or more antenna elements at Typically 2 X 2 or 4 X 4 configuration Tx and/or Rx. Tx and Rx (Tx X Rx). Tx and Rx are configurations are independent. linked by the digital signal processing algorithm. Spatial Single spatial channel focussed Multiple spatial channels, diversity between transmitter and receiver. exploiting multi-path propagation. Single bit stream encoded to all Data stream multiplexed over multiplexing transmit antennas. spatial channels. Signal Simple phase and gain modification Complex processing algorithm processing for each antenna. to decode signals over multiple spatial channels. Application 3rd generation WLAN access PHY layer for the 802.11n example points - Section "Wireless LAN standard - Section "MIMO Arrays, p. 52". and data rates to 600 Mbps (802.11n), p. 165". Also under development is a new type of switched beam wireless LAN antenna called a plasma antenna, which uses a solid-state plasma (an ionised region in a silicon layer) as a reflector to focus and direct the emitted RF beam. A plasma antenna will be able to switch a medium gain (10-15 dBi) beam with approximately 10° beamwidth to 1 of 36 directions within a full 360° coverage, with a switching time that is less than the gap between transmitted frames. Chapter Three Wireless PAN Devices Wireless PAN Hardware Devices Bluetooth Devices In Part IV the wide range of PAN technologies will be described, from Bluetooth, which is most commonly identified with personal area networking, to ZigBee, an emerging technology primarily aimed at networking home and industrial control devices. In fact with high powered (Class 1) Bluetooth radios, which can equal the range of Wi-Fi devices, the boundary between personal and local area networking is blurred and, within the limitations of achievable data rates, most of the WLAN devices described in the Section "Wireless LAN Devices p. 45" could equally well be built using Bluetooth technology. The most common types of Bluetooth d