Beam forming at Wi-Fi frequencies couldn’t happen without the 4x4 antenna scheme , says Goldsmith. This is because antennas don’t just send and receive data: they can also adapt to the channel characteristics and avoid interference. In fact, if there are two data streams, in a 4x4 antenna, then there will be extra antennas to optimize the beam’s path and to correct for disruption. “Having four antennas allows you to mitigate the impact of interference and point the beam in the optimal directions,” Goldsmith says.
Beam forming is not new, but Goldsmith and her engineers faced new challenges in ensuring that the technology would comply with the Wi-Fi standard. For one thing, they had to make sure that the chip would adjust its power levels at the antennas receiving the data quickly enough–within four microseconds, as dictated by the standard–when it went from standard Wi-Fi mode to beam-forming mode. Without giving details, Goldsmith says that her team developed algorithms that were able to handle the power adjustment more rapidly.
Other tricks include developing beam-forming algorithms to manage all the environmental information, and making sure that the connection can be corrected quickly enough when interference is detected, so that there’s no lag in wireless speed.”Beam forming is indeed a good way of improving capacity,” says Jan Rabaey, a professor of electrical engineering and computer sciences at the University of California, Berkeley. “It’s definitely something that will happen.”
Rabaey notes, however, that antennas operating at Wi-Fi frequencies must be separated by centimeters, due to the properties of the frequencies used, which imposes a lower limit on the size of the antenna arrays that can be used. Still, he suspects that this sort of chip could eventually find its way into laptops and even PDAs, if the chips can be engineered to fit.
To start with, Quantenna plans to focus on getting its chips in base stations and flat-screen televisions, considered the next big frontier in wireless. The company is working with traditional home-networking vendors, says Goldsmith, and its products will be available in Asian markets in the coming months.