Subject: Re: [6gip] continueing the discussion on B5G

From: Alexandre Petrescu <[email-masked]>
Date: Thu, 7 Jan 2021 19:02:44 +0100

I recently read an article in the New York Times where the writer tested 
a few 5G smartphones on some cellular networks and some places in USA.

He said that 5G bandwidth looked higher than 4G+ to him in some places 
but he felt that better in open areas rather than indoors.  It was not 
significantly higher, just a little bit higher.

I think what 5G needs is these intelligent reflecting surfaces which 
might help increase coverage in a more energy-efficient manner, maybe 
less risky for health, and avoid somehow in some cases societal opposition.

We cant dream about hundred Gbit/s bandwidths for IP on 6G if the 
increase from 4G to 5G bandwidths is not at leastten times more.

If 4G is 50Mbit/s and 5G is 100Mbit/s then we cant expect 6G to be 
100GBit/s.

Le 03/12/2020 à 12:32, Alexandre Petrescu a écrit :
> 3. use of meta surfaces (aka Intelligent Reflecting Surfaces).  This is
> a feature newly proposed in 6G that was never mentioned in earlier
> generations, but it is a natural tool in the bag of the radio inclined
> designer.  If range is not enough then put a reflecing surface there to
> extend the range.  New in 6G is that these surfaces seem to be more
> intelligent at PHY layer - it's not just a piece of concrete (like a
> mirror) but some nano electronics are put on it to reflect in a more
> intelligent way.

---

From: Frank Fitzek <[email-masked]>
Date: Thu, 7 Jan 2021 20:05:44 +0100

Happy New Year !

Are there already 5G SA networks? Or better on which networks did the 
author test the data rate? SA and NSA makes a huge difference.
FF

On 07/01/2021 19:02, Alexandre Petrescu wrote:
>
> I recently read an article in the New York Times where the writer 
> tested a few 5G smartphones on some cellular networks and some places 
> in USA.
>

-- 

Frank H.P. Fitzek
Professor
Deutsche Telekom Chair of Communication Networks
Institute of Communication Technology
Technische Universität Dresden

mobile: +49 151 160 00003
phone:  +49 351 463 33945
fax:    +49 351 463 37163

web:	cn.ifn.et.tu-dresden.de

5G Lab Germany - Coordinator - 5Glab.de
CeTI - Speaker - ceti.tu-dresden.de
Smart System Hub - Speaker - smart-systems-hub.de

---

From: Alexandre Petrescu <[email-masked]>
Date: Thu, 7 Jan 2021 20:09:13 +0100

> author test the data rate? SA and NSA makes a huge difference.

SA?  Security Association?
NSA?  National Security Agency?

I will gladly consider the SA/NSA distinction with the SFR and Free 
deployments I know here where I live.

But I dont know what it means.

Alex

---

From: Frank Fitzek <[email-masked]>
Date: Thu, 7 Jan 2021 20:14:40 +0100

Sorry

SA = Stand Alone (Real 5G networks)
NSA = Non Stand Alone 5G air interface with 4G networks

Most operators used NSA solution to get 5G to the mobile. So if the 
limitation is the EPC (or the connection to the EPC) , then it has 
nothing to do with 5G access.

FF.

On 07/01/2021 20:09, Alexandre Petrescu wrote:
>>> tested a few 5G smartphones on some cellular networks and some 
>>> places in USA.
>>>
>>> He said that 5G bandwidth looked higher than 4G+ to him in some 
>>> places but he felt that better in open areas rather than indoors.  
>>> It was not significantly higher, just a little bit higher.
>>>
>>> might help increase coverage in a more energy-efficient manner, 
>>> maybe less risky for health, and avoid somehow in some cases 
>>> societal opposition.
>>>

-- 

Frank H.P. Fitzek
Professor

---

From: David Lake <[email-masked]>
Date: Thu, 7 Jan 2021 19:42:24 +0000

This falls into the realm of the "bandwidth testers" on Broadband...

What was the contention on the gNB<->Aggregation link?  Where is the server they were testing with?  What was the connectivity to that?

Also, what was the profile in use on the air-interface - you can set different traffic profiles per UE.

If you look at the tight coupling of numerology and IP QoS as used in VoLTE (or Vo5GNR) then it is possible to define a proper traffic performance.

If only we had that ability on the Internet...  Once you exit N6, all bets are off.

David

From: 6gip <[email-masked]> On Behalf Of Alexandre Petrescu
Sent: 07 January 2021 18:03
To: [email-masked]
Subject: Re: [6gip] continueing the discussion on B5G

I recently read an article in the New York Times where the writer tested a few 5G smartphones on some cellular networks and some places in USA.

He said that 5G bandwidth looked higher than 4G+ to him in some places but he felt that better in open areas rather than indoors.  It was not significantly higher, just a little bit higher.

I think what 5G needs is these intelligent reflecting surfaces which might help increase coverage in a more energy-efficient manner, maybe less risky for health, and avoid somehow in some cases societal opposition.

We cant dream about hundred Gbit/s bandwidths for IP on 6G if the increase from 4G to 5G bandwidths is not at leastten times more.

If 4G is 50Mbit/s and 5G is 100Mbit/s then we cant expect 6G to be 100GBit/s.

---

From: Alexandre Petrescu <[email-masked]>
Date: Thu, 7 Jan 2021 23:22:02 +0100

Le 07/01/2021 à 20:14, Frank Fitzek a écrit :
> Sorry
> 
> SA = Stand Alone (Real 5G networks) NSA = Non Stand Alone 5G air
> interface with 4G networks
> 
> 

Thanks for the explanation.

I would expect, by feeling, that latencies in the core network based on
Ethernet are hugely lower than latencies in the air.  In that sense, the
difference NSA vs SA might not impact the feeling of the end user
comparing 5G to 4G or 4G+.

Basically, it is sufficient to download some large file from youtube and
highest definition (4K?) and try it first with a 4G text above the 5
bars showing signal quality and then with the 5G text instead.  In
theory one should be impressed by the download speed on 5G.

If the person is not impressed, I'd put the fault on the air interface,
not on the core network, be it NSA or SA.

But these are just intuitions, I dont know for sure.

MAybe we should wait for more reports.

I do not know what the New York Times reporter used for testing.  I
remember vaguely he said something about youtube but not sure.  Even if
he googled 'speed test' the results would still be relevant, because I
still think the dominant slowing factor is the air interface.

If one looks at the Internet from the smartphone perspective of latency
then the air interface is a huge bubble and the whole wired Internet is
a small dot.  If one looks at the same Internet from a router
manufacturer's perspective of bandwidth then the Internet is a huge
cloud covering the entire slide and the smartphone is a tiny mobile dot
at the edge of the cloud.

Alex

>>> Are there already 5G SA networks? Or better on which networks did
>>> the author test the data rate? SA and NSA makes a huge
>>> difference.
>> 
>> SA?  Security Association? NSA?  National Security Agency?
>> 
>>>> I recently read an article in the New York Times where the
>>>> writer tested a few 5G smartphones on some cellular networks
>>>> and some places in USA.
>>>> 
>>>>  places but he felt that better in open areas rather than
>>>> indoors. It was not significantly higher, just a little bit
>>>> higher.
>>>> 
>>>> I think what 5G needs is these intelligent reflecting surfaces
>>>> which might help increase coverage in a more energy-efficient
>>>> manner, maybe less risky for health, and avoid somehow in some
>>>> cases societal opposition.
>>>> 
>>>> We cant dream about hundred Gbit/s bandwidths for IP on 6G if
>>>> the increase from 4G to 5G bandwidths is not at leastten times
>>>> more.
>>>> 
>>>>> 3. use of meta surfaces (aka Intelligent Reflecting
>>>>> Surfaces). This is a feature newly proposed in 6G that was
>>>>> never mentioned in earlier generations, but it is a natural
>>>>> tool in the bag of the radio inclined designer.  If range is
>>>>> not enough then put a reflecing surface there to extend the
>>>>> range.  New in 6G is that these surfaces seem to be more 
>>>>> intelligent at PHY layer - it's not just a piece of concrete
>>>>> (like a mirror) but some nano electronics are put on it to
>>>>> reflect in a more intelligent way.
>>>> 
>>> 
>>> --
>>> 
>>> Frank H.P. Fitzek Professor Deutsche Telekom Chair of
>>> Communication Networks Institute of Communication Technology 
>>> mobile: +49 151 160 00003 phone:  +49 351 463 33945 fax:    +49
>>> 351 463 37163
>>> 
>>> 5G Lab Germany - Coordinator - 5Glab.de CeTI - Speaker -
>>> ceti.tu-dresden.de Smart System Hub - Speaker -
>>> smart-systems-hub.de
>>> 
>>> 
>> 
> 
> --
> 
> Frank H.P. Fitzek Professor Deutsche Telekom Chair of Communication
> Networks Institute of Communication Technology Technische Universität
> Dresden
> 
> mobile: +49 151 160 00003 phone:  +49 351 463 33945 fax:    +49 351
> 463 37163
> 
> 5G Lab Germany - Coordinator - 5Glab.de CeTI - Speaker -
> ceti.tu-dresden.de Smart System Hub - Speaker - smart-systems-hub.de
> 
>

---

From: John Grant <[email-masked]>
Date: Fri, 8 Jan 2021 15:52:04 +0000

> theory one should be impressed by the download speed on 5G. 
Are we talking latency or throughput here? And if latency is it round 
trip latency, where milliseconds can be important in some applications, 
or just the delay between requesting something and the content appearing?

-- 
John Grant
Nine Tiles, Cambridge, England
+44 1223 862599 and +44 1223 511455
http://www.ninetiles.com

-- 
This email has been checked for viruses by AVG.
https://www.avg.com

---

From: Alexandre Petrescu <[email-masked]>
Date: Fri, 8 Jan 2021 19:18:07 +0100

Le 08/01/2021 à 16:52, John Grant a écrit :
>> I would expect, by feeling, that latencies in the core network
>> based on Ethernet are hugely lower than latencies in the air.  In
>> that sense, the difference NSA vs SA might not impact the feeling
>> of the end user comparing 5G to 4G or 4G+.
>> 
>> Basically, it is sufficient to download some large file from
>> youtube and highest definition (4K?) and try it first with a 4G
>> text above the 5 bars showing signal quality and then with the 5G
>> text instead.  In theory one should be impressed by the download
>> speed on 5G.
> 
>  trip latency, where milliseconds can be important in some
> applications, or just the delay between requesting something and the
> content appearing?

It is a good question.  Smaller round or single trip latency and larger
throughput parameters have distinct influence on different apps.  A
youtube watch might not be influenced by the latter but a skype call
might be influenced by the former.

What do you think could be another smartphone easy test to demonstrate
the superiority of 5G over 4G?

Because I think at this time what can be evaluated is a feeling.

The feeling of whether 5G feels faster than 4G to the end user.

It is very easy for some users who have access to 5G smartphones and 5G
deployments to tell whether 5G feels faster than 4G.  In France, these
users are located in a few cities such as Marsilia or Nice and with
operator SFR, but need a 'business' kind of subscription.  In other
countries it might be other operators.

These deployments started in December.

So I wonder how do the 5G users feel about it being faster than 4G?  Is
it _much_ faster than 4G?  Can one download a 4Gb DVD in a few minutes
time?  What does 'google speed test' reply?

What do you think could be another smartphone easy test to demonstrate
the superiority of 5G over 4G?

Alex

---

From: Rex Buddenberg <[email-masked]>
Date: Fri, 08 Jan 2021 12:42:18 -0800

alex,

qos and QoS tends to be a murky subject.

First, in system design, QoS should be discussed _after_ 
  - availability and survivability issues.
  - security issues.
The Ao considerations often result in infrastructure density that
renders QoS discussions moot. This happens regularly in terrestrial
(wired) parts of the internet. In radio segments, things get more
complex. But remember: radio is hard and it will always be hard. So
good strategy means shrinking the radio space before tackling it
directly. That has the side effect of making the qos issues more
amenable.

Second, there are parts of qos that are in tension -- trading off to
optimize one component will cost you something elsewhere. The comment:
> Are we talking latency or throughput here? 
Starts to get to the issue. This is the list I used in the classroom:
  - bandwidth efficiency
  - throughput (closely related to b/w efficiency)
  - latency (one way) subdivided into macro and micro
  - latency (round trip)
  - synchronicity
The tradeoffs are significantly affected by MAC design. Contention
access (CSMA) which is present in all forms of ethernet (including
WiFi) yields low latency in lightly loaded network segments due low
numbers of collisions. Ethernet MACs simply listen for vacancy and
squirt packets out -- no setup foreplay. But a lightly loaded segment
is not using the bandwidth available very much. Heavily load the
network segment and you stall it from congestion. With no good way out
from an operational point of view - add more cells but that's an
infrastructure issue, not an operational one of making what you have
work.
  By contrast, scheduling MACs may cost you something in original
access (a couple of setup handshakes) but you then can get controlled
throughput, or near-synchronous behavior because the base station can
guarantee you a certain amount of capacity each frame. Something WiFi
cannot do but LTE does.
  I can't comment of 5G or 6G specifically because they have MAC
behavior that I don't (yet) understand.

One of the practical lessons in the whole QoS discussion is that the
cure is often (hell, almost always) worse than the qos disease. The
internet is littered with the debris of failed QoS regimes most of
which require a trade of stateless behavior of routers for reserved
capacity (RSVP is an example). Diff-serve doesn't compromise the
statelessness of routers but we quickly found that the CPU processing
cost outweighed the qos effects (there are several shaggy stories
herein, some bordering on farce. Helps if you have worked with US
DoD). 

Help?