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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.RegardsDavidDr 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
From: Vasanth.Rajan [mailto:vasantha.rajan@CRANESSOFTWARE.COM]
Sent: 13 September 2006 06:12
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] UL parameter acquisition
Hi Feder,Thanks for your reply......According to my understandingfor 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 meVasanth----- Original Message -----From: Peretz FederTo: Peretz FederSent: Wednesday, September 13, 2006 1:10 AMSubject: Re: [STDS-802-16] UL parameter acquisitionActually 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:
DL/UL-MAP goes in every frame to inform and schedule SS(s).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????
DCD & UCD are sent every (configurable) amount of frames.
REG-REQ MAC messageIn 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.
Thanks & reg
Vasanth