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muxdeintrlv

Restore ordering of symbols using specified shift registers

Syntax

deintrlved = muxdeintrlv(data,delay)
[deintrlved,state] = muxdeintrlv(data,delay)
[deintrlved,state] = muxdeintrlv(data,delay,init_state)

Description

deintrlved = muxdeintrlv(data,delay) restores the ordering of elements in data by using a set of internal shift registers, each with its own delay value. delay is a vector whose entries indicate how many symbols each shift register can hold. The length of delay is the number of shift registers. 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.

[deintrlved,state] = muxdeintrlv(data,delay) 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.

[deintrlved,state] = muxdeintrlv(data,delay,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 interleaver.

Using an Interleaver-Deinterleaver Pair

To use this function as an inverse of the muxintrlv function, use the same delay input in both functions. In that case, the two functions are inverses in the sense that applying muxintrlv followed by muxdeintrlv leaves data unchanged, after you take their combined delay of length(delay)*max(delay) into account. To learn more about delays of convolutional interleavers, see Delays of Convolutional Interleavers.

Examples

The example below illustrates how to use the state input and output when invoking muxdeintrlv repeatedly. Notice that [deintrlved1; deintrlved2] is the same as deintrlved.

delay = [0 4 8 12]; % Delays in shift registers
symbols = 100; % Number of symbols to process
% Interleave random data.
intrlved = muxintrlv(randi([0 1],symbols,1),delay);

% Deinterleave some of the data, recording state for later use.
[deintrlved1,state] = muxdeintrlv(intrlved(1:symbols/2),delay);
% Deinterleave the rest of the data, using state as an input argument.
deintrlved2 = muxdeintrlv(intrlved(symbols/2+1:symbols),delay,state);

% Deinterleave all data in one step.
deintrlved = muxdeintrlv(intrlved,delay);

isequal(deintrlved,[deintrlved1; deintrlved2])

The output is below.

ans =

     1

Another example using this function is in Convolutional Interleaving and Deinterleaving Using a Sequence of Consecutive Integers in MATLAB.

More About

References

[1] Heegard, Chris, and Stephen B. Wicker, Turbo Coding, Boston, Kluwer Academic Publishers, 1999.

See Also

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