You can think of most wireless networks like superhighways: inbound and outbound data signals travel in their own dedicated frequencies just as inbound and outbound traffic on a highway is separated by a median. But as with highways, traffic isn’t always evenly divided between those wireless lanes — during rush hour, there are far more cars leaving downtown then heading into it.
What if you could create a network where you could use all of its spectrum for both uploading and downloading at the same time? A prototype circuit and algorithm out of a Stanford startup called Kumu demonstrates a way to transfer data both ways at the same frequency, potentially doubling bandwidth.
“This was considered impossible to do for the past 100 years,” Sachin Katti, co-founder of the startup, told MIT Technology Review.
Radios generally use two frequencies or switch quickly between sending and receiving data on one frequency to avoid picking up their own outgoing signal, which drowns out incoming signals. The Kumu radio generates an additional signal that cancels out any interference, allowing incoming data to arrive without being interrupted. While interference-canceling technology is already in existence, it’s normally used at the edges of mobile cells to sort out clashing signals from neighboring towers.
While the initial research focuses on Wi-Fi, it could be very useful to mobile networking as well. Kumu said that because the circuit generates a new canceling signal each time a new packet is sent, it could cope with constantly changing environments, like those in a mobile network where towers are transmitting at much higher power and signals are constantly bouncing off buildings. This would be a big benefit to mobile companies like Sprint, Softbank and China Mobile, which are among the companies that
building LTE networks that send and receive at the same frequency.
Virginia Tech wireless research center director Jeff Reed told Technology Review that it takes very precise timing to build this type of radio. As a result, he is waiting to see the prototype actually demonstrated before labeling it a big advancement.
Technology Review reported that Kumu will test the radio with major wireless carriers early in 2014.