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