posted by: Paul DeBeasi
This post continues my discussion of beamforming and in this post we discuss dynamic beamforming.
Dynamic beamforming focuses RF energy in a particular direction and with a particular shape in order to increase the SNR. In a sense, it is like static beamforming in that it focuses RF energy, but it is different because the antenna array’s radiation pattern can change from frame to frame (see Figure).
Figure 1: Dynamic beamforming
Dynamic beamforming is also different from TxBF in several ways because it can:
* Dynamically change the propagation pattern on a frame-by-frame basis in order to optimize the pattern for every STA over time
* Provide SNR gain for both legacy and 802.11n STAs without requiring any changes in the STA
* Be used in conjunction with other 802.11n performance-enhancing techniques such as spatial multiplexing
* Improve both downlink and uplink performance
* Provide interference rejection
Dynamic beamforming has the potential to offer the highest SNR gain of the three beamforming technologies. Note that broadcast traffic, such as Beacon frames, will usually be transmitted using an omnidirectional pattern in order to communicate with nearby STAs in all directions. The only vendor currently offering an enterprise class dynamic beamforming technology is Ruckus Wireless.
Next time we will compare all three beamforming methods.
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