convintrlv

R2026b

Permute symbols using shift registers

Syntax

intrlvd = convintrlv(data,nrows,slope)

[intrlvd,state] = convintrlv(data,nrows,slope)

[intrlvd,state] = convintrlv(data,nrows,slope,init_state)

Description

intrlvd = convintrlv(data,nrows,slope) permutes the elements in data by using a set of nrows internal shift registers. Before the function begins to process data, it initializes all shift registers with zeros. For information about delays, see Delays of Convolutional Interleaving and Deinterleaving.

[intrlvd,state] = convintrlv(data,nrows,slope) returns a structure that holds the final state of the shift registers.

[intrlvd,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.

Examples

Apply Convolutional Interleaving to Reorder Input Data

Use the convintrlv function to reorder the input based on the shift register configuration.

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

Input Arguments

data — Input signal

vector | matrix

Input signal to be interleaved, specified as a vector or matrix. If data is a matrix with multiple rows and columns, the function processes the columns independently.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32
Complex Number Support: Yes

nrows — Number of internal shift registers

positive integer

Number of internal shift registers, specified as a positive integer. For more information, see Delays of Convolutional Interleaving and Deinterleaving.

slope — Register length step

positive integer

Register length step, specified as a positive integer. For more information, see Delays of Convolutional Interleaving and Deinterleaving.

init_state — Initial state of registers

structure

Initial state of registers, typically specified by using the state output from a previous call to this same function. The initial state of registers is unrelated to the corresponding deinterleaver.

Output Arguments

intrlvd — Interleaved data

vector | matrix

Interleaved data, returned with the same dimensions and data type as the input data.

state — Final state of shift registers

structure

Final state of the shift registers after the previous call to this function, returned as a structure with these fields:

value — Unshifted symbols

vector

Unshifted symbols, returned as a vector.

index — Index of next register to be shifted

positive integer

Index of the next register to be shifted, returned as a positive integer.

More About

Delays of Convolutional Interleaving and Deinterleaving

The total delay due to a convolutional interleaver and deinterleaver pair is N × slope × (N – 1).

• N is the number of registers and equals the value of the nrows argument

• slope is the register length step and equals the value of the slope argument

The structure of a general convolutional interleaver comprises a set of shift registers, each having a specified delay D(1), D(2),..., D(N), and a commutator to switch input and output symbols through registers. The kth shift register holds D(k) symbols, where k = 1, 2, 3, … N. The kth shift register has a delay value of ((k–1) × slope). With each new input symbol, the commutator switches 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 commutator returns to the first register.

References

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

Version History

Introduced before R2006a