Re: [STDS-802-16] DLFP and HFDD
Baraa,
The SS will not be able to decode the burst from the time it decoded
the UL to the end of the DL burst. For e.g.
DL burst started at time = t0
DL burst ends at time = t1 (t0 < t1)
UL burst from SS starts at time = t2 (t0 < t2 < t1)
UL burst from SS ends at time = t3 (t0 < t2 < t3 < t1)
The HFDD SS can decode DL burst from t0 to t2.
It can transmit UL from t2 to t3.
It can't decode DL from t3 to t1 primarily because
1. There is no preamble for the SS to resync to the DL.
2. The scrambler seed is initialized only at the begining of the burst.
I am also not sure if the DL from (t0,t2) can be partially decoded as the
Convolution Coder is terminated at the end of the DL burst. Maybe the PHY
can rely on only the RS ?
Regards,
-Raja
-----Original Message-----
From: Itzik Kitroser [mailto:itzikk@RUNCOM.CO.IL]
Sent: Friday, May 14, 2004 8:53 AM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16] DLFP and HFDD
Baraa,
If I remember correctly (and now all the details of standard are a big
mess in my head), then we had a comment that clarified this issue.
Anyway, the BS should avoid giving UL allocations to a specific SS,
which overlaps with DL PDUs to same SS.
Therefore, an SS receiving an UL allocation may assume that there is no
awaiting DL PDU during the same time period.
Regards,
Itzik.
-----Original Message-----
From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On Behalf Of Al Dabagh,
Baraa
Sent: Friday, May 14, 2004 4:39 PM
To: STDS-802-16@listserv.ieee.org
Subject: [STDS-802-16] DLFP and HFDD
Folks,
I have a question regarding the DLFP and DL/UL allocations (OFDM 256)
in an HFDD based system:
It seems to be possible that an UL allocation can be in conflict with
one of the DL allocation specified in the FCH (or the DLFP0 for a
particular SS. In the case were there is a conflict, should the SS
assume that there is no allocation for it in the DL burst specified by
the FCH (or the DLFP) and attempt not to decode it, or should the MAC on
the BS be smart enough to allocate on a per PDU level (rather than a
burst level)?
If the answer is the second option, then this assumes the SS will decode
a DL burst, extract the PDUs that belong to it from the burst, and if
there is an allocation on the UL overlapping then it should terminate
the DL burst decoding, and start transmitting data!! The same thing
applies for a broadcast or multicast CID specified in the DL MAP that
overlaps with an UL allocation.
Thanks
Baraa Al-Dabagh
BWD
Intel Corporation
baraa.al.dabagh@intel.com
Phone: 408-545-6078