4 ms·

I don't know anything about LiFi, but for EM radiation in general, the higher the frequency, the higher the theoretical maximum bandwidth. https://en.wikipedia

I don't know anything about LiFi, but for EM radiation in general, the higher the frequency, the higher the theoretical maximum bandwidth. https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore... Wifi is 2.6 Ghz or 5Ghz, visible red light is 430 terahertz. Or it sounds like LiFi is just pulsing the lights on an off, in which case the Nyquist Rate that was invented for telegrams is a better analogy https://en.wikipedia.org/wiki/Nyquist_rate https://en.wikipedia.org/wiki/Nyquist_rate

rbanffy 3y ago
Just imagine what we'll be able to do with Gamma data transmissions ;-) I like to explain to my kids that it's all colors - we are transparent to some (such as X-rays) the same way some fish are mostly transparent to the light we can see and walls are transparent to the radios we use in Wi-Fi, and also that both snakes and bees can see light in colors we can't (snakes see IR, bees see UV).
- noobface 3y ago
  Face melting speed.
sinak 3y ago
I think you're misreading Shannon's Law. It's not that the higher the frequency the greater the max bandwidth. It's the higher the bandwidth the more data you can put through.
- OnACoffeeBreak 3y ago
  I am agreeing with you and providing more info: https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore... Maximum channel capacity depends on signal bandwidth and SNR.
makeworld 3y ago
> the higher the frequency, the higher the theoretical maximum bandwidth. This is not true and is unrelated to Shannon's theorem. Shannon's theorem shows us that wider bandwidths allow for larger bit rates. At higher frequencies our bandwidths can be bigger. For example a band from 1 to 2 terahertz is 1 terahertz wide, which is 1000 times larger than a band from 1 to 2 gigahertz (1 gigahertz wide). The total bandwidth available (including multiple channels) for 2.4 GHz Wi-Fi is about 100 MHz. The total space available for this new standard is 800 to 1000 nm [0], which is 450 THz. That's 4.5 million times wider than Wi-Fi. That is why you get higher bit rates with this new standard, AKA more throughput, or more "bandwidth", when the term is used to mean data rate. [0]: https://standards.ieee.org/ieee/802.11bb/10823/ https://standards.ieee.org/ieee/802.11bb/10823/
- metacritic12 3y ago
  I mean it sort of is true. If you're at 100THz, you can get a bandwidth of 1THz. If you're at 100KHz, you are not going to get a bandwidth of 1THz.
  - Isamu 3y ago
    True, The “band” is a range of frequencies, from lower bound to upper bound. You can have a single frequency carrier that you modulate, in which case your bandwidth has more to do with your modulation scheme, and the rates implied by that
- deely3 3y ago
  Can I ask a noob question? Suppose we have 1Hz signal, what stopping us from sending/receiving 10 or 100 bits of info every second by modulationg amplitude of signal?
  - p_j_w 3y ago
    When you modulate that 1 Hz signal you're generating power at frequencies other than your 1 Hz carrier. See https://en.wikipedia.org/wiki/Amplitude_modulation#Spectrum https://en.wikipedia.org/wiki/Amplitude_modulation#Spectrum

rbanffy 3y ago

Just imagine what we'll be able to do with Gamma data transmissions ;-) I like to explain to my kids that it's all colors - we are transparent to some (such as X-rays) the same way some fish are mostly transparent to the light we can see and walls are transparent to the radios we use in Wi-Fi, and also that both snakes and bees can see light in colors we can't (snakes see IR, bees see UV).

noobface 3y ago
Face melting speed.

sinak 3y ago

I think you're misreading Shannon's Law. It's not that the higher the frequency the greater the max bandwidth. It's the higher the bandwidth the more data you can put through.

OnACoffeeBreak 3y ago
I am agreeing with you and providing more info: https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore... Maximum channel capacity depends on signal bandwidth and SNR.

makeworld 3y ago

> the higher the frequency, the higher the theoretical maximum bandwidth. This is not true and is unrelated to Shannon's theorem. Shannon's theorem shows us that wider bandwidths allow for larger bit rates. At higher frequencies our bandwidths can be bigger. For example a band from 1 to 2 terahertz is 1 terahertz wide, which is 1000 times larger than a band from 1 to 2 gigahertz (1 gigahertz wide). The total bandwidth available (including multiple channels) for 2.4 GHz Wi-Fi is about 100 MHz. The total space available for this new standard is 800 to 1000 nm [0], which is 450 THz. That's 4.5 million times wider than Wi-Fi. That is why you get higher bit rates with this new standard, AKA more throughput, or more "bandwidth", when the term is used to mean data rate. [0]: https://standards.ieee.org/ieee/802.11bb/10823/ https://standards.ieee.org/ieee/802.11bb/10823/

metacritic12 3y ago
I mean it sort of is true. If you're at 100THz, you can get a bandwidth of 1THz. If you're at 100KHz, you are not going to get a bandwidth of 1THz.
- Isamu 3y ago
  True, The “band” is a range of frequencies, from lower bound to upper bound. You can have a single frequency carrier that you modulate, in which case your bandwidth has more to do with your modulation scheme, and the rates implied by that
deely3 3y ago
Can I ask a noob question? Suppose we have 1Hz signal, what stopping us from sending/receiving 10 or 100 bits of info every second by modulationg amplitude of signal?
- p_j_w 3y ago
  When you modulate that 1 Hz signal you're generating power at frequencies other than your 1 Hz carrier. See https://en.wikipedia.org/wiki/Amplitude_modulation#Spectrum https://en.wikipedia.org/wiki/Amplitude_modulation#Spectrum