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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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