3 ms·

Not if the antennas are all carrying the same signal. In the described system, the antennas get phase adjustments, but they do not get different signals, and th

by lutusp 13y ago

Not if the antennas are all carrying the same signal. In the described system, the antennas get phase adjustments, but they do not get different signals, and this idea doesn't rely on multiple, independent data channels. So the Nyquist-Shannon sampling theorem still applies.

cma 13y ago
I imagine it is something like a XOR-swap: http://en.wikipedia.org/wiki/XOR_swap_algorithm http://en.wikipedia.org/wiki/XOR_swap_algorithm I imagine two phones X and Y and one antenna sends X XOR Y while the other sends X XOR Y XOR Y. A phone getting both signals could determine X and Y, but it would take twice as much bandwidth. If you can XOR the signals in the air through superposition somehow, X might be received in one location, and Y in another. So 2 antennas cant service more than 2 phones at full speed, but they can service those two phones at full bandwidth. This might not seem like an advantage over directional antennas, but it relaxes the physical constraint of making sure the phones are in two separate enough places to be serviceable by the two antennas. Like maybe your phone would have two antennas and get twice the data--not very feasible if your phone were somehow serviced by two directional antennas. I haven't worked out how superposition could do something exactly like XOR, or if it maybe has a minimum of 3 antennas to start being possible, etc., but it seems plausible. Anyway, the idea would be sending signal X and Y. You want X interfering with Y at some time offset to yield desired phone signal A, and X interfering with Y at some other time offset to yield phone signal B. The phones never receive X or Y, but some superposition of the two, The phones couldn't cheat and just record the two waves and timeshift internally to yield twice the bandwidth, because they don't receive the two waves separately, they only get the superposition of the two.
- bsder 13y ago
  It's called CDMA: https://en.wikipedia.org/wiki/Code_division_multiple_access https://en.wikipedia.org/wiki/Code_division_multiple_access XOR is just a primitive way of making an orthogonal code.

by lutusp 13y ago

cma 13y ago

I imagine it is something like a XOR-swap: http://en.wikipedia.org/wiki/XOR_swap_algorithm http://en.wikipedia.org/wiki/XOR_swap_algorithm I imagine two phones X and Y and one antenna sends X XOR Y while the other sends X XOR Y XOR Y. A phone getting both signals could determine X and Y, but it would take twice as much bandwidth. If you can XOR the signals in the air through superposition somehow, X might be received in one location, and Y in another. So 2 antennas cant service more than 2 phones at full speed, but they can service those two phones at full bandwidth. This might not seem like an advantage over directional antennas, but it relaxes the physical constraint of making sure the phones are in two separate enough places to be serviceable by the two antennas. Like maybe your phone would have two antennas and get twice the data--not very feasible if your phone were somehow serviced by two directional antennas. I haven't worked out how superposition could do something exactly like XOR, or if it maybe has a minimum of 3 antennas to start being possible, etc., but it seems plausible. Anyway, the idea would be sending signal X and Y. You want X interfering with Y at some time offset to yield desired phone signal A, and X interfering with Y at some other time offset to yield phone signal B. The phones never receive X or Y, but some superposition of the two, The phones couldn't cheat and just record the two waves and timeshift internally to yield twice the bandwidth, because they don't receive the two waves separately, they only get the superposition of the two.

bsder 13y ago
It's called CDMA: https://en.wikipedia.org/wiki/Code_division_multiple_access https://en.wikipedia.org/wiki/Code_division_multiple_access XOR is just a primitive way of making an orthogonal code.