06-12-2012, 02:49 PM
Beamforming Antennas for Wireless Communications
beamforming antennas.ppt (Size: 1.53 MB / Downloads: 140)
Vector antennas vs. spatial array antennas
Vector antennas measure: and power simultaneously, no phase shift device, or synchronization is needed.
Phased array antennas with omnidirectional element measure: ,, and power
Beamforming antennas in ad hoc networks
Medium Access Control Protocol(CSMA/CA)
CSMA/CA:carrier sense multiple access/collision avoidance
( for omnidirectional antennas)
No obvious improvement for throughput using beamforming antennas
Neighbor discovery become more complex using beamforming antennas.
Ad hoc networks may achieve better performance in some cases using beamforming antennas.
Beamforming antennas can significantly increasing node and network lifetime in ad hoc networks.
Conclusion
Beamforming antenna systems improve wireless network performance
-increase system capacity
-improve signal quality
-suppress interference and noise
-save power
Beamforming antennas improve infrastructure networks performance. They may improve ad hoc networks performance. New MAC protocol standards are needed.
Vector antennas may replace spatial arrays to further improve beamforming performance