Re: [STDS-802-16] Broadcast
The issue of data broadcast needs to be understood in the context of what
CS service you are providing.
Broadcast data (as opposed to broadcast management) is a feature of the
CS service. So for example 802.1 defines broadcast behaviour within the
context of 802. This is not completely trivial, the behaviour of 802
broadcast data on an 802 network is subject to a number of rules. The
behavior at the 802.16 MAC CPS layer is the multicast service.
At present it is the job of the CS to map between the CS broadcast
service and the MAC CPS multicast service. I submitted a few comments
about the need to clarify the CS broadcast behavior in order to make both
ends of the link behave the same.
So if a CS is presenting and 802 broadcast service, it needs to know who
is in the 802 broadcast group and set up a multicast group to all these
SSs. You may be doing something different to the default. There may be
VLANs or provider bridging or distinct, isolated 802 networks being
served to users.
So in 802.16, broadcast data is not broadcast data. It is a specially
managed aspect of the MAC CPS multicast service to provide an equivalent
to a CS layer broadcast service.
If we want to go down a route of defining broadcast data in the MAC CPS,
then we need to have a reason.
E.G.
A MAC CPS layer broadcast service will enable CS layer broadcast
service with lower on air management messaging
or
A MAC CPS layer broadcast service will prevent redundant
specification of broadcast behaviour in multiple CS specs.
I don't see that either of these is true. Therefore I don't see a need
for a broadcast CID on the downlink.
On the uplink, there is no broadcast. Data goes only to the BS, since
that is what the PHY layer supports. The CS is free to create a multicast
CID to provide that function.
So I see no need to a broadcast CID in the MAC CPS.
DJ
-----Original Message-----
From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On Behalf Of Ken
Stanwood
Sent: Wednesday, April 21, 2004 8:48 AM
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Broadcast
The basic situation is this:
1. The "Broadcast" connection that currently exists was
intended for MAC usage. There is now way to indicate a user
service over it.
2. Multicast polling groups are just that, polling groups,
not connections. The "CID" is a replacement for the SS's
Basic CID which is actually used in maps a a shortened SS ID
rather than really a connection ID.
3. Terminals are unaware whether a connection is multicast
or unicast, with the exception of it having a different
security association.
4. A broadcast DL connection would be established today by
setting up a connection with the same parameters to all
SS's. It's data would need to be transmitted in a region
that all SS's could listen to, or be re-broadcast to sets of
SS's if no such region existed as could possibly happen with
AAS or DL OFDMA.
We should consider whether a true broadcast well-known
connection would be useful. If so, I recommend putting it in
16e since it's an extra feature.
Ken
________________________________________________________________________________
From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On Behalf Of
Pedro Neves
Sent: Wednesday, April 21, 2004 4:42 AM
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Broadcast
The draft does not specify one broadcast and one multicast
connection for sending data from the BS to the SSās?
As Vladimir said, multicast polling groups are used, but what
about data transfer from the BS to the SSās? I thought CIDs
were allocated for this type of transmissions.
Regards,
Pedro Neves
--------------------------------------------------------------------
Pedro Miguel Naia Neves
Instituto Telecomunica^Ķ^Ūes - http://www.av.it.pt
Aveiro - Portugal
Phone: +351 234 377 900
Mobile: +351 96 618 75 82
Homepage: http://daidalos.av.it.pt/~pneves
MSN contact: etneves@hotmail.com
________________________________________________________________________________
From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On Behalf Of
Vladimir Yanover
Sent: quarta-feira, 21 de Abril de 2004 12:06
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Broadcast
Eyal,
Seems that the standard does not preclude from sending data
over broadcast connection. Another question is whether
we may establish a service flow associated with broadcast
connection. I think, we cannot, then there is no way
for data entering CS SAP to be routed to broadcast
connection.
By the way, multicast connections are not related to
multicast [polling] groups.
Vladimir
-----Original Message-----
From: Eyal Verbin [mailto:everbin@AIRSPAN.COM]
Sent: Wednesday, April 21, 2004 1:39 PM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: [STDS-802-16] Broadcast
Section 6.1 of the standard states that " In
addition to individually addressed messages,
messages may also be sent on multicast
connections (control messages and video
distribution are examples of multicast
applications) as well as broadcast to all
stations."
Correct me if I'm wrong, but broadcast
transmission is limited to MAC management
messages (MAPs, DCD,...) and can't be used to
transfer data. Therefore, the only way to
broadcast data is to form a multicast group
containing all SS's
Eyal
-----Original Message-----
From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org]On
Behalf Of Don Leimer
Sent: Monday, April 19, 2004 8:26 PM
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Clarification
regarding SS power level control
Only one more comment. The final 4dB of error
will also be reduced by subsequent BS commands,
and relative error diminishes to +/- 0.5dB for
the final error (relative to the BS's capability
to measure power)
-----Original Message-----
From: Raja Banerjea
[mailto:RBanerjea@PROXIM.COM]
Sent: Monday, April 19, 2004 9:14 AM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16]
Clarification regarding SS power
level control
The power control method is a closed
loop method where the Base station
asks for further power control
corrections if required. If the base
station requests the subscriber
station in the RNG-RESP to increase
the power level by 30dB the SS should
increase it by 30dB with a relative
accuracy of 4dB.
If the Base station is going to
increase the power of the SS
in 5 steps and the BS requests the SS
to increase the power by 8dB the SS
will increase it by 8dB with a
relative accuracy of 4dB. In the
subsequent RNG-RESP message the BS
instead of requesting a power
increase of 8dB will request for
8dB+(relative accuracy).
Therefore after each increase
requested from the BS the relative
accuracy should be 4dB.
This assumes that the BS can make an
accurate measurement of the SS's
power increase.
Any comments ?
Regards,
-Raja
-----Original
Message-----
From: Crozier, Eugene
[mailto:Eugene_Crozier@SRTELECOM.COM]
Sent: Monday, April 19,
2004 6:26 AM
To:
STDS-802-16@listserv.ieee.org
Subject: Re:
[STDS-802-16]
Clarification regarding
SS power level control
My understanding of this
is that the step size
should be greater than 1
dB but less than 8 dB
(I'd assumed for the
relative accuracy that
the 50% of the step size
can be no more than 4
dB), but the number of
steps is based on the
step size and the
relative accuracy to
achieve the minimum
control range, so for 1
dB steps, the number of
steps can be between 60
and 20 (30/0.5 and
30/1.5) for a 30 dB
range, and for 8 dB step
size the number of steps
between 8 and 3 for the
30 dB range.
Regards
Eugene Crozier
-----Original
Message-----
From: Eyal
Verbin
[mailto:everbin@AIRSPAN.COM]
Sent: Monday,
April 19,
2004 8:22 AM
To:
STDS-802-16@listserv.ieee.org
Subject:
[STDS-802-16]
Clarification
regarding SS
power level
control
Power level
control for
the OFDM PHY
is defined in
section
8.3.9.1:
" For an SS
not
supporting
subchannelization,
the
transmitter
shall support
a monotonic
power level
control of 30
dB minimum.
For an SS
supporting
subchannelization,
the
transmitter
shall support
a monotonic
power level
control of 50
dB minimum.
The minimum
step size
shall be no
more than 1
dB. The
relative
accuracy of
the power
control
mechanism is
+/-50% of the
step size in
dB, but no
more than 4
dB. As an
example, for
a step size
of 5 dB the
relative
accuracy is
2.5 dB. For a
BS, the
transmitter
shall support
a monotonic
power level
control of 10
dB minimum."
Looking at
the SS
(subchannelization)
for example,
it is
possible to
go from Min
power to Max
power either
in 5 steps of
8 dB or in a
single step
of 50dB. In
the first
option the
accumulated
offset can
reach 5*4dB
(20dB) wheras
in the second
option the
tolerance is
limited to
4dB.
Does anyone
have a more
clear
interpretation
of this text?
Eyal Verbin
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