OFDMA sub channelization

[reach2rsa]

ofdma uplink matlab code

HI,
I was going through the WiMAX document available at Wimax Forum.
What is "OFDMA sub channelization".
Anybody can explain in detail or upload the document for detail understanding.
Thanks in advance.

 

[scoppulal]

wimax pusc subchannelization matlab code

In the easiest way I can:

Sub- channelisation could be used to allow a tx with low power
to have a good performance too.

Is a way of grouping a sub-set of the OFDM available carriers,
this way the entire power could be used only for that sub-set.

In other word, you won't waste power where is not needed.

Hope it helps.

 

[changfa]

wimax ul pusc subcarrier mapping

If I remember correctly, subchannelization in WiMAX is to group a number of subcarriers. When MAC layer allocates resources, it can only access to subchannel, but not physical subcarriers.

Note that subchannelization is dependent on permutation scheme and Uplink/Downlink.

 

[pshl]

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.

 

[tarakapraveen]

ofdma subchannelization

Tiles are also like our time slots but they do have restrictions in subcarriers direction..i.e our Tiles are SymbolsXSubcarriers Matrix.Mostly per each tile we are assigning 48 subcarriers.These tiles only we are using for scheduling.

In Single carrier case we don't have have diamension of subcarriers only Symbols/slots avaialbe .
In Multicarrier case we have two diamensions.If we want to schedule we have to do based on subchannel SNR for that terminal..

Regards,
Tarak