Can someone ELI5 the advantage of terahertz (or sub-) communications over the plethora of currently available alternatives? Is there any edge to switching a signal to that high of a carrier frequency?
People focus too much on bandwidth, but latency is more important. Bandwidth has increased exponentially, but the speed of light has stayed the same for more than 10 years now.
> but the speed of light has stayed the same for more than 10 years now.
Don't worry, i bet that in the next time we will read on HN about revolutionary methods to increase the speed of light, just like those articles about fusion, charging or batteries. /s
It's usually stated in meters per second, a somewhat dry, cognitively inaccessible number. Try flipping it around though ..
3.336 microseconds per kilometer
People, software engineering types anyway, have a feel for what a microsecond is; a CPU can get a quite noticeable amount of work done in a microsecond - and it takes three and a third of those just to reach the coffee shop on the corner! Jump across a continent, and now you're talking latencies on par with early 1980s disk systems.
That being said, there's not too much you can do about the latency, 3E8 is the law, so we may as well fiddle with bandwidth.
I was wondering why they used the term "sub-terahertz" (isn't basically the entire RF spectrum "sub-terahertz"?), and it seems to refer to the ~75-300ghz range [0][1], including the W and D bands.
While looking into this, I learned that terahertz frequencies are called THF or "tremendously high frequency"[2], which I thought was pretty funny. Pretty used to HF, VHF, UHF etc. but never heard of "THF" until now!
Starting from VHF, the ITU names the bands in this order: very, ultra, super, extremely, and tremendously high. I once asked several of my friends who don’t know anything about radio to try to name the bands in ascending order after I scrambled them, and they all gave me different, incorrect answers.
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[ 2.9 ms ] story [ 34.1 ms ] threadDon't worry, i bet that in the next time we will read on HN about revolutionary methods to increase the speed of light, just like those articles about fusion, charging or batteries. /s
Little practical communication is constrained by the speed of light.
3.336 microseconds per kilometer
People, software engineering types anyway, have a feel for what a microsecond is; a CPU can get a quite noticeable amount of work done in a microsecond - and it takes three and a third of those just to reach the coffee shop on the corner! Jump across a continent, and now you're talking latencies on par with early 1980s disk systems.
That being said, there's not too much you can do about the latency, 3E8 is the law, so we may as well fiddle with bandwidth.
"We can't send email more than 500 miles"
https://web.mit.edu/jemorris/humor/500-miles
While looking into this, I learned that terahertz frequencies are called THF or "tremendously high frequency"[2], which I thought was pretty funny. Pretty used to HF, VHF, UHF etc. but never heard of "THF" until now!
[0] https://www.rfwireless-world.com/Terminology/Sub-THz-Bands-a...
[1] http://www.brave-beyond5g.com/index.php/sub-thz/
[2] https://books.google.ca/books?id=K9N1TVhf82YC&pg=PA7&redir_e...