Decode Bluetooth LE PHY waveform

Since R2019b

## Syntax

``[bits,accessAddr] = bleIdealReceiver(waveform)``
``[bits,accessAddr] = bleIdealReceiver(waveform,Name,Value)``
``[___,IQsamples] = bleIdealReceiver(___)``

## Description

example

````[bits,accessAddr] = bleIdealReceiver(waveform)` decodes the Bluetooth® low energy (LE) physical layer (PHY) waveform, `waveform`, generated by the `bleWaveformGenerator` function. The function returns the received bits, `bits`, and the access address information, `accesAddr`.```

example

````[bits,accessAddr] = bleIdealReceiver(waveform,Name,Value)` also specifies options using one or more name-value pair arguments. For example, `'Mode','LE2M'` sets the PHY transmission mode of the desired Bluetooth LE waveform to `'LE2M'`.```

example

````[___,IQsamples] = bleIdealReceiver(___)` additionally returns the in-phase and quadrature (IQ) samples, `IQsamples`, corresponding to constant tone extension (CTE).```

## Examples

collapse all

Create an input message column vector of length 1000 containing random binary-valued transmission bits.

`txBits = randi([0 1],1000,1);`

Generate a Bluetooth LE transmit waveform from the transmission bits by using the `bleWaveformGenerator` function.

`txWaveform = bleWaveformGenerator(txBits);`

Pass the transmit waveform through a noisy channel and obtain the received waveform.

```snr = 30; % In dB rxWaveform = awgn(txWaveform,snr);```

Recover data bits from the received Bluetooth LE waveform. Check for the number of bit errors in the recovered bits. The returned value indicates that the function successfully decodes the Bluetooth LE waveform.

```[rxBits,accessAddr] = bleIdealReceiver(rxWaveform); numErr = biterr(txBits,rxBits)```
```numErr = 0 ```

Specify the values of PHY transmission mode, channel index and samples per symbol (sps).

```phyMode = 'LE125K'; chanIndex = 2; sps = 4;```

Generate transmission bits containing random binary values.

`txBits = randi([0 1],100,1);`

Obtain the Bluetooth LE transmit waveform from the transmission bits and the specified name-value pairs using the `bleWaveformGenerator` function.

```txWaveform = bleWaveformGenerator(txBits,'Mode',phyMode,... 'SamplesPerSymbol',sps,'ChannelIndex',chanIndex);```

Recover the data bits, and then compare them with the transmission bits. The recovered data bits match the transmission bits, indicating there are no errors in the decoded Bluetooth LE waveform.

```rxBits = bleIdealReceiver(txWaveform,'Mode',phyMode,... 'SamplesPerSymbol',sps,'ChannelIndex',chanIndex); isequal(txBits,rxBits)```
```ans = logical 1 ```

Specify a connectionless advertising channel protocol data unit (PDU) for angle of arrival (AoA) CTE.

```pduHex = '02049B0327'; pdu = int2bit(hex2dec(pduHex),40,false);```

Generate and append cyclic redundancy check (CRC) to the PDU.

```crcGen = comm.CRCGenerator('z^24+z^10+z^9+z^6+z^4+z^3+z+1', ... 'InitialConditions',int2bit(hex2dec('555551'),24), ... 'DirectMethod',true); pduCRC = crcGen(pdu);```

Generate the Bluetooth LE transmit waveform.

```txWaveform = bleWaveformGenerator(pduCRC,'ChannelIndex',36, ... 'DFPacketType','ConnectionlessCTE');```

Recover the data bits by demodulating, dewhitening, and IQ sampling for a slot duration of 2 $\mu \mathit{s}$.

```[bits,accAddr,iqSamples] = bleIdealReceiver(txWaveform, ... 'ChannelIndex',36,'DFPacketType','ConnectionlessCTE');```

## Input Arguments

collapse all

Received time-domain signal, specified as a complex-valued signal with size Ns-by-1, where Ns represents the number of received samples. The values of Ns depend on the `'Mode'` and `'SamplesPerSymbol'` input arguments, according to the constraints specified in this table.

Value of `'Mode'` Value of NsMultiple of
`'LE1M'`

`40`×sps

sps
`'LE2M'`

`48`×sps

sps
`'LE500K'`

`376`×sps

`2`×sps
`'LE125K'`

`376`×sps

`8`×sps

Data Types: `double` | `single`

### Name-Value Arguments

Specify optional pairs of arguments as `Name1=Value1,...,NameN=ValueN`, where `Name` is the argument name and `Value` is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose `Name` in quotes.

Example: `bleIdealReceiver(waveform,'Mode','LE2M','ChannelIndex',36)`

PHY transmission mode, specified as the comma-separated pair consisting of `'Mode'` and `'LE1M'`, `'LE2M'`, `'LE500K'`, or `'LE125K'`. This value indicates the type of PHY that the function uses to decode the received Bluetooth LE waveform.

Data Types: `char` | `string`

Channel index, specified as the comma-separated pair consisting of `'ChannelIndex'` and an integer in the range [0, 39]. For data channels, specify this value in the range [0, 36]. This value is used by the data-dewhitening block.

Data Types: `double`

Samples per symbol, specified as the comma-separated pair consisting of `'SamplesPerSymbol'` and a positive integer. The object uses this value for Gaussian frequency shift keying (GFSK) modulation.

Data Types: `double`

Type of direction finding packet, specified as the comma-separated pair consisting of `'DFPacketType'` and `'ConnectionlessCTE'`, `'ConnectionCTE'`, or `'Disabled'`.

Data Types: `char` | `string`

Switch and sample slot duration, specified as the comma-separated pair consisting of `'SlotDuration'` and `1` or `2`. Specify this value in microseconds.

Data Types: `double`

Data whiten status, specified as `'On'` or `'Off'`. Set this value to `'On'` for the function to perform dewhitening on the demodulated bits (for `'LE1M'` and `'LE2M'` PHY) and the decoded bits (for `'LE500K'` and `'LE125K'` PHY).

Data Types: `char` | `string`

## Output Arguments

collapse all

Payload bits, returned as a column vector of maximum length 260 bytes. This output represents the recovered information bits.

Data Types: `int8`

Access address information, returned as a 32-bit column vector. The higher layers use this output to validate a packet.

Data Types: `int8`

IQ samples, specified as a complex-valued column vector. This argument corresponds to the 8 μs value of the reference period and slot duration. If you set the value of DFPacketType argument to `'ConnectionlessCTE'` or `'ConnectionCTE'`, then the function returns this output.

Data Types: `double`

## References

[1] Bluetooth Technology Website. “Bluetooth Technology Website | The Official Website of Bluetooth Technology.” Accessed November 22, 2021. https://www.bluetooth.com/.

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

## Version History

Introduced in R2019b