[STDS-802-16] FW: [STDS-802-16] Question: Downlink subchannels subcarrier allocation in PUSC
Bala,
Yes, I do understand how to use Eq. 111. What I can't figure out is the
relationship between clusters and subchannels and the role of renumbering in
step 2 of subcarrier allocation in DL PUSC. For instance, what is subchannel
0 made of? Clusters 0 & 1? Then what happens after renumbering? Will it be
clusters 6 & 108 (according to renumbering sequence). In that case, how is
Eq. 111 used to reflect the renumbering of clusters, i.e. how are the 24
subcarriers in a given subchannel spread over the entire band to reflect
that renumbering?
Regards,
Vafa
-----Original Message-----
From: balchand [mailto:balchand@tenet.res.in]
Sent: Thursday, May 12, 2005 1:07 AM
To: vafa@ieee.org; STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Question: Downlink subchannels subcarrier
allocation in PUSC
Hi,
Firstly, a number of clusters that are spread accross the entire physical
band are grouped into a group. For eg, group-0 contains logical clusters
0-23 which are phsically spread all over the band. now, permutaions have to
performed within this group using formula 111. Now 0-23 clusters would have
288 data subcarriers(336 including pilots). Each subchannel should have 24
data subcarriers in each symbol resulting in 288/24=12. so, in formula 111,
substitute Nsubchannels=12, k ranges from 0-23 and s ranges from 0-11. thus
clustering helps to spread the subcarriers in a group to spread over the
entire band.
hth
bala
-----Original Message-----
From: vafa@ieee.org
Date: Tue, 10 May 2005 11:05:05 -0700
To: STDS-802-16@listserv.ieee.org
CC:
Subject: [STDS-802-16] Question: Downlink subchannels subcarrier allocation
in PUSC
Hi,
I have a question regarding "Downlink subchannels
subcarrier allocation in PUSC", section 8.4.6.1.2.1.1 of the 802.16
standard (i.e. document 802.16-2004 and the corrections in P80216_Cor1_D2).
While steps 1-3 consistently refer to clusters, which are made up of 2 pilot
and 12 data subcarriers, steps 4 & 5 suddenly switch to subchannels, which
are made up of 2 clusters. In step 4, it is stated that the same procedure
in
section 8.4.6.1.2.2.2 (i.e. Eq. 111) is to be used for allocation of
subcarriers to subchannels, using either PermutationBase 12 or 8. These
permutations can only be used, if subchannels are considered, which are made
up
of two clusters.
My question is:
How are clusters mapped to subchannels? Specially after
renumbering, two adjacent clusters can be mapped to clusters that are apart.
How is the Eq. 111 then used to map subcarriers to subchannels? I have
difficulty understanding the relationship between subchannels and clusters,
especially after renumbering the clusters.
Thank you in advance.
Vafa
Vafa
Ghazi,
Ph.D.
Principal
Software
Engineer
SPW
Business
Unit
CoWare
Inc.
Email:
vafa@coware.com