wimax ul pusc subchannelization
OFDMA subchannelization UL PUSC
In IEEE Stds. 802.16-2004 and 802.16e-2005, I have been studying the
subchannelization used for the uplink (UL) Partially Used SubCarriers
(PUSC) zone but it does not yet make complete sense to me.
For example in 2048FFT, the following parameters are defined (according to
table 313):
N_used = 1681;
N_subcarriers = 48;
N_subchannels = 70;
N_tiles = 420;
N_subcarriersPerSym = 24;
Figure 236 describes an uplink tile:
X O O X Symbol 0 X = pilot carrier
O O O O Symbol 1 O = data carrier
X O O X Symbol 2
Equation 113 defines the tile matrix which can be encoded as:
% The tile index
n = 0:5;
% Tile permutation
Pt = TilePermutation;
for s = 1:N_subchannels
tile(s,
= N_subchannels .* n + ...
mod(Pt(1+mod(s+n, N_subchannels)) + UL_PermBase, N_subchannels);
end
Equation 114 defines the subcarrier mapping matrix which can be encoded
as:
% n is a running index
n = 0:47;
for s = 1:N_subchannels
subcarrier(s,
= mod( (n+13*s), N_subcarriers);
end
subcarrier = subcarrier.';
But what should one do with this...
How are the pilots assigned?
What is the tile matrix used for?
How is the subcarrier mapping matrix used?
The FFT has 1681 useable taps. What goes into each tap?
Section 8.4.9.4.4 gives an example of OFDMA uplink CC coding and shows the
"mapping onto subcarriers and multiplying by PN..." The Symbol Number and
Subcarrier Index together with the IQ-pair are given. How are the Symbol
Number and Subcarrier Index calculated?
Please try to help me understand this. I am not asking for MATLAB code
(but if you have it it would be appreciated), perhaps a link to a paper or
presentation.
Thanks in advance.