Hi David,
From the replies got, I
have two kinds of understandings; I will give it below
For
instance let’s assume the number DL-burst in DL-sub frame does not exceed ‘4’
then,
- DL-Map message won’t be framed in the
MAC layer and the FCH is filled by the Phy layer according to the MAC Pdu
sent by the MAC layer and the DL-Map message will only be generated in the
MAC layer when lost DL-Map interval is exhausted, and at this particular
point both the FCH & DL-Map will contain burst profile encoding of the
all the 4 DL-Burst.
Or it will work in other way as
given below
- FCH will fill the
burst profile encoding of the first 4 DL-burst’s from the information got
from DL-Map message generated in the Mac layer (but I don’t know really
after getting burst profile information from Dl-Map whether the Phy layer
will reject the DL-Map i.e. not transmitted, b’coz as u said DL-Map messages
wont be transmitted in every DL-subframe)
Plz clear my doubt as my
confused…
Thanks
Vasanth
----- Original Message -----
Sent: Thursday, September 14, 2006 6:39
PM
Subject: Re: [STDS-802-16] UL parameter
acquisition
And this does not specify that it is transmitted
when it alters, rather when it is needed. The DLFP can contain the
descriptions of up to 4 bursts, so there is no need to use a DL-MAP if the
frame contains fewer bursts. Therefore the downlink transmissions will
frequently NOT contain a DL-MAP (at least in lightly loaded systems, or ones
with only a few burst profiles defined), though will, with probability close
to 1, contain a UL-MAP.
David:
802.16-2004:
"A DL-MAP
message, if transmitted in the current frame, shall be the
first MAC PDU in the burst following the FCH. An UL-MAP message shall
immediately follow either the DL-MAP (if one is transmitted)
or the DLFP."
On 9/13/2006 4:53 AM, David Castelow wrote:
Peretz, Vasanth,
I think you may both be confused: Peretz, it
would be useful if you could quote the section from where you derive the
idea that the maps are only sent when they alter. This is not the
case (IMHO). The DL-MAP
may or may not be sent in every frame per the standard above. I do
agree with you that practically speaking (IMHO as well) DL-MAP and of course
UL-MAP should be sent in each and every frame.
In the OFDM PHY (section 8.3) the UL-MAP is
sent in every frame, even if it were empty: note the wording in
8.3.5.1: it "shall immediately follow". (not that I expect it would
be empty very often, as in a quiet network you will still require IR
opportunities). The DL-MAP is not necessarily sent every frame,
because the DLFP can contain the descriptions of up to the first
4 bursts in the frame, but the DL-MAP also provides additional
information that is needed for synchronisation, so must be sent
occasionally (more often than the Lost DL-MAP interval, otherwise the SS
will sign off: again see 8.3.5.1). This is the reason that the
DL-MAP is not always sent.
There are no sign-in problems for 802.16 equipment: interoperable
systems are already working.
Regards
David
Dr David
Castelow
Airspan Communications
Ltd
Principal Systems
Engineer Cambridge House, Oxford Road
DSP & Systems Design
Uxbridge UB8 1UN, UK
http://www.airspan.com
+44 1895 467281
Hi Feder,
Thanks for your reply......
According to my understanding
for e.g. if I select a MAC frame
duration of 10ms, the BS station will send DL-MAP & UL MAP in
every DL subframe (provided the if the MAP messages changes)if I
went wrong plz note me...
UL_MAP:
But,when the BS is initialized and if there
are no SS to receive the MAP messages, in DL subframe period(i.e
for every 10 ms completes) the BS has to transmit UL map b'coz the BS
has to provide initial ranging period in UL MAP message so that If any
SS receives the MAP messages will contend & send the RNG-REQ frame
& also the BS will not know when new SS will enter the
NW.
DL-MAP:
And let's assume the DL MAP messages are
never changed so the BS will never send the DL-MAP and if any new SS
station wants to enter the NW then it cant be synchronized with the DL
channel unless it receives DLMAP msg???
Sorry for a long mail....If I
went wrong plz correct me
Vasanth
-----
Original Message -----
Sent:
Wednesday, September 13, 2006 1:10 AM
Subject:
Re: [STDS-802-16] UL parameter acquisition
Actually DL-MAP, UL-MAP shall
be sent whenever the maps are changed.(See
8.3.5.1)
On 9/12/2006 1:43 PM, Peretz Feder wrote:
On 9/12/2006 2:50 AM, Vasanth.Rajan wrote:
Hi all,
I have some doubt in Scanning & UL parameter
acquisition
When the BS is initialized it will send first
DL-MAP frame; my question is following the DL-MAP should the BS send UL-MAP frame before transmitting DCD
& UCD frames???? DL/UL-MAP
goes in every frame to inform and schedule SS(s).
DCD & UCD
are sent every (configurable) amount of frames.
In STD 802.16-2004,6.3.9.4 Table 114,Message flow
during scanning & UL parameter acquisition process,
Its given that once the SS achives DL
syncronization & obtains the UL channel information and then
the BS transmits UL-MAP message...How come the
BS know that a particular SS has Syncronized with DL & obtained UL channel parameters????so that it
could transmit UL-MAP
frame. REG-REQ MAC message
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