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comm.MultiplexedDeinterleaver

Deinterleave symbols using set of shift registers with specified delays

Description

The comm.MultiplexedDeinterleaver System object™ deinterleaves the symbols in the input sequence by using a set of shift registers, each with its own specified delay. The deinterleaver uses N shift registers, where N is the number of elements in the vector specified by the Delay property. When a new input symbol enters the deinterleaver, the System object switches the commutator to a new register and shifts in the new symbol while shifting out the oldest symbol in that register. When the commutator reaches the Nth register, upon the next new input, the System object returns to the first register. The multiplexed deinterleaver that is associated with the comm.MultiplexedInterleaver System object has the same number of registers as the interleaver. The delay in a particular deinterleaver register depends on the difference between the largest interleaver delay and the interleaver delay for the given register. For more information, see Interleaving.

To deinterleave the symbols in the input sequence:

  1. Create the comm.MultiplexedDeinterleaver object and set its properties.

  2. Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects?

Creation

Description

muxdeinterleaver = comm.MultiplexedDeinterleaver creates a default multiplexed deinterleaver System object.

example

muxdeinterleaver = comm.MultiplexedDeinterleaver(Name,Value)sets the Properties by using one or more name-value arguments. For example, 'InitialConditions',1 sets the initial conditions of shift registers to 1.

Properties

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Unless otherwise indicated, properties are nontunable, which means you cannot change their values after calling the object. Objects lock when you call them, and the release function unlocks them.

If a property is tunable, you can change its value at any time.

For more information on changing property values, see System Design in MATLAB Using System Objects.

Interleaver delay, specified as a column vector of integers. The values in this vector specify the lengths of the shift registers.

Data Types: double

Initial conditions of the shift registers, specified as one of these options.

  • Numeric scalar — The default value is 0. The specified scalar applies to all shift registers.

  • Column vector — The length of this vector must be equal to the length of the Delay property value. The ith initial condition applies to the ith shift register.

Data Types: double

Usage

Description

deintrlvseq = muxdeinterleaver(intrlvseq) deinterleaves the input sequence of symbols, deintrlvseq, by using a set of shift registers with delays specified by the Delay property. The System object returns the deinterleaved sequence, deintrlvseq.

Input Arguments

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Interleaved sequence of symbols, specified as a column vector. This sequence must be one that was interleaved using the comm.MultiplexedInterleaver System object.

Data Types: double | logical | fi

Output Arguments

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Deinterleaved sequence of symbols, returned as a column vector with the same data type and size as the intrlvseq argument.

Data Types: double | logical | fi

Object Functions

To use an object function, specify the System object as the first input argument. For example, to release system resources of a System object named obj, use this syntax:

release(obj)

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stepRun System object algorithm
releaseRelease resources and allow changes to System object property values and input characteristics
resetReset internal states of System object

Examples

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Create a multiplexed interleaver System object, specifying the interleaver delay.

interleaver = comm.MultiplexedInterleaver('Delay',[1; 0; 2; 1]);

Create a multiplexed deinterleaver System object, specifying the interleaver delay.

deinterleaver = comm.MultiplexedDeinterleaver('Delay',[1; 0; 2; 1]);

Generate a random data sequence. Pass the data sequence through the interleaver and then the deinterleaver.

[dataIn,dataOut] = deal([]); % Initialize data arrays

for index = 1:50
    data = randi([0 7],20,1);
    intrlvSequence = interleaver(data);
    deintrlvSequence = deinterleaver(intrlvSequence);
    % Save original data and deinterleaved data
    dataIn = cat(1,dataIn,data);
    dataOut = cat(1,dataOut,deintrlvSequence);
end

Determine the delay through the interleaver and deinterleaver.

delay = finddelay(dataIn,dataOut)
delay = 8

After accounting for the delay, confirm that the original and deinterleaved sequences are identical.

isequal(dataIn(1:end-delay),dataOut(delay+1:end))
ans = logical
   1

Copyright 2012 The MathWorks, Inc.

References

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

Extended Capabilities

Introduced in R2012a