I invoke the name of Aaron Schneider and he appears!
I am the dungeon master of AFMUG!
I see your point. In a nutshell the problem is that we are marketing
bits per second, but what we actually have to hand out is air time. We
can try to deliver the bps that everybody wants, but then we might not
be distributing air time in an efficient way. We can distribute air
time in an efficient way, but then some people won't get the bps they want.
IMO, it is OK to to simply switch on equal time scheduling for whole
AP. Consider Eric Muehleisen's thread from last week. Subject: "450
frame utilization and performance issues". He's got a whole AP that
doesn't go above 23mbps. Trying to deliver full speed to every customer
no matter how bad their signal is might mean that everybody suffers. He
also has an external system capping speed (as do a lot of other
people). I have a suspicion that distributing equal airtime rather than
equal bits per second would interact more favorably with an external
system like that. Though you're probably in a better position than me
to comment on that.
On 11/13/2015 11:04 AM, Aaron Schneider wrote:
The Canopy scheduler operates with a combined priority based scheme and a round
robin based scheme. As has been covered here in the past, the scheduling
priority is as follows: 1) High Priority CIR 2) Low Priority CIR 3)
Bcast/Mcast CIR 4) High Priority 5) Low Priority 6) Bcast/Mcast.
If you don't oversubscribe your CIR, then things are fine. But, that is very
tricky when you assume CIR based on one data rate (say 8x), and the actual link
requiring that CIR is different (say 4x). Now, that SM is requiring twice as
much frame time to meet that CIR as you may have planned. This goes to the
concept of allocating capacity based on throughput, and it is generally how
Canopy works. The round robin comes in so that one SM can't take everything on
its own, it will try to be fairer, but, it will still do everything it can to
honor the CIRs of each SM in every frame.
We do have a feature in the works where we flip that a bit where the CIR
becomes airtime based so generally speaking, you are guaranteeing air time and
not throughput. The idea is that you will assign a CIR based on a given rate,
say 8x, and if the SM drops (or can only ever achieve) 4x, then they will get
half the data rate because they are only allowed the same amount of time as if
they were 8x. The underlying concept is easy, it is the external interface and
making it easily understood and helping you stay out of trouble with
configurations that is difficult. If it is OK to just say turn on the
option, but then not be able to predict the throughput, that's one thing, but
if you have a customer that needs a given throughput no matter what his data
rate becomes, and other customers that are OK with just having limited airtime
access, then the overall planning of CIR becomes tricky to not over-commit.
So what would you all prefer? An option per sector to enforce CIR in a given
way for all SMs? Or enforce CIR in a selectable way (throughput vs. air time)
per individual SMs on a given sector?
Regards,
-Aaron
-----Original Message-----
From: Af [mailto:[email protected]] On Behalf Of Adam Moffett
Sent: Friday, November 13, 2015 8:28 AM
To: [email protected]
Subject: Re: [AFMUG] LTE Speeds
Maybe it already does? They say capacity is allocated proportional to sustained rate when there's
contention....do they mean "capacity" in bps or "capacity" in time slots. I'm
thinking it's the latter because I have observed that if you improve the data rate of an individual
SM he'll get more, which makes sense if the SM's capacity allotment is measured in timeslots rather
than bits.
Where's Aaron Schneider when you need him?
On 11/13/2015 9:14 AM, Craig Schmaderer wrote:
Cambium if it is at all possible please please add this to the 450!!!!!
On Nov 12, 2015, at 4:51 PM, Dan Petermann <[email protected]> wrote:
LTE can be set for equal time or equal rate. Equal rate will drag down the
thruput of all users.
Equal time will only impact the user with a poor signal. If everyones signal is
great and one users radio signal is bad, that user only gets the thruput that
can be crammed into his timeslot because his modulation is low. Everyone else
continues as normal.
At least that is my understanding.
On Nov 12, 2015, at 3:01 PM, Adam Moffett <[email protected]> wrote:
....any system with 20mhz channels + two chains + 256QAM can claim 100mbps.
Getting past that is going to be carrier aggregation (bigger channels) and
MU-MIMO.
5x20mhz channels aggregated = 500mbps.
MU-MIMO can theoretically double capacity. So there's your 1gig.
I'm not clear on how far you can count on MU-MIMO. In theory it sounds
promising.
....and yes, one person at MIMO-A QPSK is going eat up many times the capacity
of a person at 256QAM MIMO-B no matter what wireless system you're using. The
best defense against that will be don't install bad connections. Nothing new
there.
If you're going to use 100mhz, you could of course install 5 AP's of your
choice and claim you have a 500mbps system.
On 11/12/2015 4:47 PM, Matt wrote:
Hear talk of these 50 - 100+ mbps speeds per user and eventually 1
gbps. How can LTE do that in 10 to 20 mhz of spectrum? I assume
if you are offering 50 mbps package in a sector its safe to assume
at prime time there are going to be at the very least 10 people
using it in that sector at the same time? Also assume some have
less then perfect connections to the tower using more air time.
