Stanford Wireless Breakthrough
drdobbs.com
drdobbs.com
That's going up on the wall above my monitor.
http://sing.stanford.edu/fullduplex/
The problem with full duplex wireless comm. on the same frequency is that the transmitted signal is much stronger than the received signal. Therefore, echo cancelling is usually impractical.
Not sure how these guys overcame the difficulties with transmitter nonlinearities and other unknown impairments.
EDIT: they claim to do partial cancellation by placing the receiver antenna at the null of the two transmitting antennas (getting 50 dB reduction in echo power). Whether this is practical in a commercial low cost radio remains to be seen.
This is easy and practical because they're in a location which is fixed by the PCB/housing. There's no phased array required.
This scheme also works only if all nodes have full-duplex setups, which is impractical for small devices.
It may raise the amount that can be sent over the network in toto, assuming that data demand is the same in all directions. Which it almost never is.
So what they've done is, they allow the data uplink to occur simultaneously with the downlink.
A valid claim is, the latency of data is improved - you don't have to wait/schedule your sends around the receive traffic. Which can matter quite a bit in the bulk of cases e.g. downloading http while jabbing buttons/sending commands up to the server.
Rather than think about bursty, asymmetric Ethernet bits, consider passing something like a fully allocated T1 over it. Symmetric TDM links aren't totally dead, there are a lot of T1 radios out there. What used to take X Hz of bandwidth, theoretically can be done in X/2...without changing the modulation.
I don't think it will actually be used that way, but it is a breakthrough of sorts to be able to do so.
I believe that is the entire point of the article. To allow double the capacity between two devices. The original capacity would be the amount of data that could be sent by a single device. However if both devices can send at the same time that is double capacity.
To be fair, the article improved after that.
i don't think any textbooks makes that claim. from the article: ...a researcher even told the students their idea was "so simple and effective, it won't work," because something that obvious must have already been tried unsuccessfully.
> "Textbooks say you can't do it," said Philip Levis, assistant professor of computer science and of electrical engineering.
200 years ago, people might have believed you. Then Fourier showed that your statements contradict each other. He said a lot of other interesting things - Bracewell's book is a good introduction.