Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Wednesday, December 3, 2003Slide 1 Tuesday, March 01, 2016 Smart Antennas Breed Better WLANs Jack H. Winters Chief Scientist Motia, Inc. December 3,

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Wednesday, December 3, 2003Slide 2 2 Smart Antennas Smart antenna is a multibeam or adaptive antenna array that tracks the wireless environment to significantly improve the performance of wireless systems Adaptive arrays in any environment provide: Antenna gain of M Suppression of M-1 interferers In a multipath environment, they also provide: M-fold multipath diversity gain With M Tx antennas (MIMO), M-fold data rate increase in same channel with same total transmit power SIGNAL OUTPUT SIGNAL INTERFERENCE BEAMFORMER WEIGHTS SIGNAL OUTPUT BEAM SELECT SIGNAL BEAMFORMER Adaptive Antenna Array Switched Multibeam Antenna

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Wednesday, December 3, 2003Slide 3 3 Smart Antennas for WLANs TDD operation (only need smart antenna at access point or terminal for performance improvement in both directions) Higher antenna gain  Extend range/ Increase data rate/ Extend battery life Multipath diversity gain  Improve reliability Interference suppression  Improve system capacity and throughput –Supports aggressive frequency re-use for higher spectrum efficiency, robustness in the ISM band (microwave ovens, outdoor lights) –Data rate increase  M-fold increase in data rate with M Tx and M Rx antennas (MIMO n) Smart Antennas can significantly improve the performance of WLANs AP Smart Antenna Interference AP Smart Antenna Smart Antenna

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Wednesday, December 3, 2003Slide 4 4 Smart Antennas for WLANs Smart Antennas can (and to be successful should): Be standards compliant Work with any antennas: Two antennas on APs and clients today Four antennas in same space (e.g., PCMCIA card) with dual polarization Can be added to existing systems for slight cost increase Can be added to AP or client: On AP: All AP users have greater range Higher system capacity On client: Greater range Interference immunity On both: Gains are additive Evolution to MIMO with standards (802.11n)

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Wednesday, December 3, 2003Slide 5 5 Adaptive Array Appliqué Existing Transceiver Javelin Chip Four-antenna RF IC with analog weight calculation (plug-and-play/blind MRC Tx and Rx) provides: dB gain (vs. one antenna) in Rayleigh fading with b/g 7-10 dB gain with ns delay spread Increases throughput by 50% (typical) Reduces power drain by up to 90%