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New Full Duplex Radio Chip Transmits and Receives Wireless Signals At Once (ieee.org)
Wave723 writes: A new chip by Columbia University researchers uses a circulator made of silicon transistors to reroute signals and avoid interference from a transmitter and receiver that share the same antenna. This technology instantly doubles data capacity and could eventually be built into smartphones and tablets. The chip enables them to work around the principle of Lorentz Reciprocity, in which electromagnetic waves are thought to always travel along the same path both forward and backward. Traditionally, electronic devices required two antennas -- a transmitter and receiver -- that took turns or operated on different frequencies in order to exchange signals.
so department of redundancy department strikes again!
Circulators are used all of the place (radar, satcom), so nothing new. But one small and efficient enough to potentially work in a cellphone? Neat stuff. They come with their own set of tradeoffs, so it might not be worth it in the end for smartphone use, but will find use somewhere.
Instantly doubles data capacity? I DID notice my phone seemed faster this morning! Good job Columbia!
This is just two radios with one antenna, which is not a new concept. The radios are still half-duplex, but two of them working together provides a full duplex connection.
Pretty cool. Not the first active circulator, but nonetheless pretty cool. I wonder how much isolation they are getting? http://www.wenzel.com/wp-conte...
That is the news here. Normally circulators are made of ferrite... amirite?
It doesn't sound right using "at once", but then, you are an AMERICAN, aren't you...
Listening while talking is a major issue for all shared communications links including wireless. Cable TV Internet and *PON based systems all have the problem that they can blind the receiver while transmitting resulting in talking over another speaker resulting in resending packets.
Personally, I find "simultaneously" to be a better term here than either "at once" or "at the same time." Alas, it's totally not a topic worth nitpicking about.
"at once" - I take to mean "immediately".
"all at once" - I take to mean "simultaneously".
Like a lot of Slashdot-edited articles - close, but no cigar.
The gist of what is clever here is the canceller which removes the transmitted signal from the receiver. Circulators have been around for donkey's years (not just in military systems) but they are bulky (especially at lower frequencies such as those for mobile comms). The are often used to allow a single antenna to operate at both transmit and receive either alternately (e.g. radar) or on different frequencies (e.g. satcom). Making a solid state one is clever, but this isn't the first one.
However, some of your transmit signal will always end up in the receiver for three reasons; (a) the circulator isn't perfect, (b) the antenna doesn't have a perfect match so some of the transmit energy sent to it bounces back again and (c) energy can reflect back from the immediate environment. Cancelling schemes exist, and invariably consist of some mechanism for sampling the transmitted signal and feeding just the right amount back into the receiver exactly out of phase. In theory this works, but in most practical circumstances the extremely high level of cancellation needed requires a completely unachievable precision.
For added pain, the solution tends to be very narrow band and the cancellor's settings have to be continually updated as the transmit interference changes (particularly in a mobile environment due to (c)).
If they have managed to make this work in a practical and useful way then it will be very impressive, but I would need to see some real world experiments to be convinced of its practicality.
Geeze, what happened to those 0.1" jumpers? Looks like they melted. Did someone accidentally the soldering iron on them?
"You saved 1968." - Ms. Valerie Pringle to the crew of Apollo 8
Personally, I find "simultaneously" to be a better term here than either "at once" or "at the same time." Alas, it's totally not a topic worth nitpicking about.
However, I commend your successful attempt to comment and nitpick on it at the same time - wait, I mean ... damn.
It must have been something you assimilated. . . .
"at once" - I take to mean "immediately".
"all at once" - I take to mean "simultaneously".
Like a lot of Slashdot-edited articles - close, but no cigar.
If we're really going to nitpick phrasing that bugs us, I'd like to nominate the use of "all new" to describe *one* TV show episode. Grrrr....
It must have been something you assimilated. . . .
Technically, if they say it's "all-new", is it able to legally contain flashback or be a "best-of" revisited episode in any part?
I'd love to be a millionaire just to spent time suing things into oblivion when they are inaccurate like this. Shampoo adverts I'd target first, followed by any commercial use of the phrase "Unlimited".
Someone should use this to build a network of free internet by using the extra data and wifi signals all around.
What do you take "all offer sodden" to mean?