Permute symbols using shift registers
intrlved = convintrlv(data,nrows,slope)
[intrlved,state] = convintrlv(data,nrows,slope)
[intrlved,state] = convintrlv(data,nrows,slope,init_state)
intrlved = convintrlv(data,nrows,slope) permutes
the elements in data by using a set of nrows internal
shift registers. The delay value of the kth shift register is (k-1)*slope,
where k = 1, 2, 3,... nrows. Before the function
begins to process data, it initializes all shift registers with zeros.
If data is a matrix with multiple rows and columns,
the function processes the columns independently.
[intrlved,state] = convintrlv(data,nrows,slope) returns
a structure that holds the final state of the shift registers. state.value stores
any unshifted symbols. state.index is the index
of the next register to be shifted.
[intrlved,state] = convintrlv(data,nrows,slope,init_state) initializes
the shift registers with the symbols contained in init_state.value and
directs the first input symbol to the shift register referenced by init_state.index.
The structure init_state is typically the state output
from a previous call to this same function, and is unrelated to the
corresponding deinterleaver.
The example below shows that convintrlv is
a special case of the more general function muxintrlv.
Both functions yield the same numerical results.
x = randi([0 1],100,1); % Original data nrows = 5; % Use 5 shift registers slope = 3; % Delays are 0, 3, 6, 9, and 12. y = convintrlv(x,nrows,slope); % Interleaving using convintrlv. delay = [0:3:12]; % Another way to express set of delays y1 = muxintrlv(x,delay); % Interleave using muxintrlv. isequal(y,y1)
The output below shows that y, obtained using convintrlv,
and y1, obtained using muxintrlv,
are the same.
ans =
1
Another example using this function is in Effect of Delays on Recovery of Convolutionally Interleaved Data Using MATLAB.
The example on the muxdeintrlv reference
page illustrates how to use the state output and init_state input
with that function; the process is analogous for this function.
[1] Heegard, Chris, and Stephen B. Wicker, Turbo Coding, Boston, Kluwer Academic Publishers, 1999.