Re: [6gip] 6G

[Alexandre Petrescu <[e-mail]>]

Le 14/01/2021 à 13:45, Lars Eggert a écrit :
> On 2021-1-14, at 14:41, Alexandre Petrescu 
> <[e-mail]> wrote:
>> In year 2030, when 6G does 1us (micro-second) latency, maybe LAN 
>> does 1ns (nano-second) latency.
>> 
>> Of course, for LAN to do 1ns there is a need for short cables and 
>> multiple flows of light carrying data.
> 
> Yes, short cables of at most 30cm, due to speed-of-light.

Right, probably.

It might be that cables and fibers already (and always have) transmit
each bit at almost the speed of light, even though the bandwidths we
experienced across generations has always increased.

In that sense, maybe it is the electronics who are the culprit
preventing one from experiencing 500Gbit/s on 6G.  Maybe improving the
electronics will lead to higher bandwidths, and consequently lower
latencies.

I suspect that, as in computing, adding parallelization will set the sky
as the only limit to reducing the latency.

Of course, a zero latency couldnt be reached, but micro-seconds is still
far from 0.  A particular mantra in future networking talks about 'zero
latency' as well, but that might have to do with quantum Internet, in
the QIRG of IRTF.  Maybe another suggestion suggests data to be there
before it was even sent, which might question causality overall; but
micro-seconds latency is not questioning causality, because it is a
positive number.

> Multiple flows do not decrease latency, they (only) increase 
> throughput.

Hmm, but there has always been a tight relationship between bandwidth
(throughput?) and latency on the same medium.  On Ethernet, higher
bandwidth meant lower latency.  On 3G, 4G, 4G too.  On WiFi too.

Also, one parameter of throughput is the size of the data to be sent.
Distributing that data on two channels halves that size, so throughput
is increased.

With these two things I think I can reasoably assume that ping on 6G
might display micro-second latencies (RTT, round trip time)?

Or maybe hundreds of micro-seconds latency on 6G?

Or maybe milli-seconds latency on 6G?

Alex