bluetoothWhiten

Whiten or dewhiten input data bits

Since R2022b

Description

The bluetoothWhiten System object™ whitens or dewhitens input data bits by using a linear feedback shift register (LFSR). The Bluetooth^® Core Specification v5.3 [2] specifies the generator polynomial $${}^{x^7+x^4+1}$$ and initial values of LFSR.

To whiten or dewhiten input data bits:

1. Create the bluetoothWhiten 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?

Note

For more information about Bluetooth data whitening and dewhitening, see Volume 2, Part B, Section 7.2 and Volume 6, Part B, Section 3.2 of the Bluetooth Core Specification v5.3 [2].

Creation

Syntax

whiten = bluetoothWhiten

whiten = bluetoothWhiten(Name=Value)

Description

whiten = bluetoothWhiten creates a default Bluetooth whitening or dewhitening System object.

whiten = bluetoothWhiten(Name=Value) sets properties by using one or more optional name-value arguments. For example, InitialConditionsSource="Input port" sets the input port as the source of the initial conditions vector.

Properties

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.

InitialConditionsSource — Source of initial conditions vector

"Property" (default) | "Input port"

Source of the initial conditions vector, specified as "Property" or "Input port".

Data Types: char | string

InitialConditions — Initial conditions of LFSR

[1;1;1;1;1;1;1] (default) | seven-element column vector of binary values

Initial conditions of the LFSR, specified as a seven-element column vector of binary values. For the System object to generate an output different from the input data, at least one element of this property must be nonzero.

Data Types: double

Usage

Syntax

y = whiten(x)

y = whiten(x,initCondition)

Description

y = whiten(x) whitens or dewhitens the input data bits, x, at the transmitter or receiver, respectively, and returns the result, y.

y = whiten(x,initCondition) whitens or dewhitens the input data by using the specified initial values of the LFSR, initCondition.

Input Arguments

x — Input data bits

column vector of binary values

Input data, specified as a column vector of binary values.

Data Types: double | logical

initCondition — Initial conditions of LFSR

seven-element column vector of binary values

Initial conditions of LFSR, specified as a seven-element column vector of binary values. To specify this input,you must set the InitialConditionsSource property of whiten to "Input port". For the System object to generate an output different from the input data, at least one element of this input must be nonzero.

Data Types: double

Output Arguments

y — Whitened or dewhitened output data bits

column vector of binary values

Whitened or dewhitened output data bits, returned as a column vector of binary values with the same length and data type as x.

Data Types: double | logical

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)

Common to All System Objects

step	Run System object algorithm
release	Release resources and allow changes to System object property values and input characteristics
clone	Create duplicate System object
isLocked	Determine if System object is in use
reset	Reset internal states of System object

Examples

Whiten Random Data Based on Channel Index

Specify a channel index.

channelIndex = 4;

Generate initial conditions from the channel index.

initCond = [1; int2bit(channelIndex,6)];

Create a Bluetooth whiten System object, specifying the input port as the source of the initial conditions vector.

whiten = bluetoothWhiten(InitialConditionsSource="Input port");

Generate random input data.

data = randi([0 1],1024,1)

data = 1024×1

     1
     1
     0
     1
     1
     0
     0
     1
     1
     1
      ⋮

Whiten the input data.

whitenedData = whiten(data,initCond)

whitenedData = 1024×1

     1
     1
     1
     1
     1
     1
     1
     1
     0
     1
      ⋮

Whiten and Dewhiten Random Data

Specify the initial conditions of a shift register.

initCond = [1 0 1 1 0 0 0]';

Create two System objects, one for whitening the input data, and the other for dewhitening the whitened data.

whiten = bluetoothWhiten(InitialConditions=initCond);
dewhiten = bluetoothWhiten(InitialConditions=initCond);

Generate random input data.

data = randi([0 1],800,1);

Whiten the input data.

whitenedData = whiten(data);

Perform dewhitening on the whitened data and, verify that the dewhitened output is same as the original, generated data.

deWhitenedData = dewhiten(whitenedData);
isequal(data,deWhitenedData)

ans = logical
   1

References

[1] Bluetooth Technology Website. “Bluetooth Technology Website | The Official Website of Bluetooth Technology.” Accessed March 22, 2022. https://www.bluetooth.com/.

[2] Bluetooth Special Interest Group (SIG). "Bluetooth Core Specification." Version 5.3. https://www.bluetooth.com/.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2022b