If I have an AP which can do implicit Tx beamforming, can I make the AP do tx beamforming with any of the station chipsets that are generally available in the current generation laptops ((Intels 5300/6300 or Broadcom 434x)? From what I understand about implicit beamforming (thanks to a CWNP article), the beamformee (station) should respond with a "sounding" Null data frame and I dont know if that is supported by all 11n capable hardware, or something that is available only in some newer generation chipsets.
TxBF is part of the 802.11n standard. As far as I know, it is not an optional feature. It only depends on how many Rx radios the receiver has. If your products are Wi-Fi certified, you have no reason to worry.
Here's a clearer explanation:
[quote]An advantage of 802.11n TxBF is that it?s standards-based, meaning that TxBF capable equipment will work with any other interoperability-certified (read: Wi-Fi Alliance) TxBF capable equipment. Another advantage is that it allows the transmitters to continue using an omni-directional RF pattern, which prevents hidden node problems. The disadvantage is that there won?t be an 802.11n TxBF-capable, Wi-Fi Alliance certified piece of equipment on the market for quite some time to come. Several chipset vendors will soon release chipsets that support 802.11n TxBF, but even after these chipsets are released into the market, it will still be a significant amount of time before that translates into interoperability-certified devices available for sale.[/quote]
You might also find this article useful: https://www.cwnp.com/index/cwnp_wifi_blog/transmit-beamforming-with-implicit-feedback
To ram's question, the answer is neither. Beamforming is optional in 802.11n, and very few chipsets made today support it. The newest client chipsets today still don't support beamforming, so even though the latest enterprise APs are beginning to support it, we will still be waiting a while before it is used. Even then, the calibration process for TxBF is not perfect, so we're unlikely to see any performance gains that match the theoretical gains. In addition to that, by using TxBF, you have to sacrifice features like spatial multiplexing. In a lot of ways, standardized beamforming is not all that exciting.