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lrwpanWaveformGenerator

Generate low-rate wireless personal area waveform

Since R2023a

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Syntax

wave = lrwpanWaveformGenerator(data,cfg)
wave = lrwpanWaveformGenerator(data,cfg,Name=Value)
[wave,symbols] = lrwpanWaveformGenerator(___)

Description

wave = lrwpanWaveformGenerator(data,cfg) generates a waveform for the specified input, data, and physical layer (PHY) format configuration, cfg. For more information, see IEEE 802.15.4 PPDU Format.

example

wave = lrwpanWaveformGenerator(data,cfg,Name=Value) specifies additional options using one or more name-value pair arguments. For example, lrwpanWaveformGenerator(data,cfg,NumPackets=30) specifies a waveform containing 30 PPDU packets.

example

[wave,symbols] = lrwpanWaveformGenerator(___) also returns symbols, the HRP signal before pulse shaping. The symbols output contains the modulated signal after the preamble insertion. This syntax applies only when cfg is an lrwpanHRPConfig configuration object.

Examples

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Open Live Script

Generate random data for a PHY Service Data Unit (PSDU) payload. Create an OQPSK IEEE 802.15.4 lrwpanOQPSKConfig object. Create an OQPSK IEEE 802.15.4 waveform.

       psdu = randi([0,1],127*8,1);
       spc = 8;
       cfgOQPSK = lrwpanOQPSKConfig( ...
           SamplesPerChip=spc, ...
           PSDULength=length(psdu)/8); % PSDU length in bytes

Generate an OQPSK IEEE 802.15.4 waveform by using the lrwpanWaveformGenerator function and cfgOQPSK configuration object. The waveform generator loops PSDU length as needed to use all input PSDU payload bits. Display the waveform by using the eyediagram function.

       waveOQPSK = lrwpanWaveformGenerator(psdu,cfgOQPSK);
       eyediagram(waveOQPSK(1+spc:end-spc), 2*spc);

Figure Eye Diagram contains 2 axes objects. Axes object 1 with title Eye Diagram for In-Phase Signal, xlabel Time, ylabel Amplitude contains an object of type line. This object represents In-phase. Axes object 2 with title Eye Diagram for Quadrature Signal, xlabel Time, ylabel Amplitude contains an object of type line. This object represents Quadrature.

Open Live Script

Generate random data for a PHY Service Data Unit (PSDU) payload. Create an HPRF IEEE 802.15.4z lrwpanHRPConfig object.

psdu = randi([0,1],8*200,1);
cfgHPRF = lrwpanHRPConfig(Mode='HPRF', ...
    Channel=3, ...                % Mandatory low-band channel
    MeanPRF=124.8, ...            % 16 chips per payload symbol
    STSPacketConfiguration=1, ... % Enable STS before payload
    NumSTSSegments=2, ...         % 2 STS segments
    CodeIndex=27, ...             % One 91-symbols long SYNC code
    PreambleDuration=32, ...      % Repetitions for spread SYNC code
    SFDNumber=1, ...              % Choose a 4-symbol long SFD
    ConstraintLength=7, ...       % Convolutional encoder, no RS coding
    PSDULength=100);              % PSDU length in bytes

Generate an HPRF IEEE 802.15.4z waveform by using the lrwpanWaveformGenerator function and cfgHPRF configuration object. The waveform generator loops PSDU length as needed to use all input PSDU payload bits. Display the waveform by using a spectrumAnalyzer object.

waveHPRF = lrwpanWaveformGenerator(psdu,cfgHPRF);
sa = spectrumAnalyzer(SampleRate=cfgHPRF.SampleRate);
sa(waveHPRF);

Open Live Script

Generate random data for a PHY Service Data Unit (PSDU) payload. Create a BPRF IEEE 802.15.4z lrwpanHRPConfig object. BPRF payload data rate is always at 6.81 Mbps.

psdu = randi([0,1],8*100,1);
cfgBPRF = lrwpanHRPConfig(Mode='BPRF', ...
    STSPacketConfiguration=0, ... % Turn off STS
    PHRDataRate=6.81, ...         % PSDU header data rate in Mbps
    CodeIndex=9, ...              % A 127-symbols long SYNC code
    PSDULength=length(psdu)/8);   % PSDU length in bytes

Generate an BPRF IEEE 802.15.4z waveform by using the lrwpanWaveformGenerator function and cfgBPRF configuration object. The waveform generator loops PSDU length as needed to use all input PSDU payload bits. Display the waveform by using a spectrumAnalyzer object.

waveBPRF = lrwpanWaveformGenerator(psdu,cfgBPRF);
sa = spectrumAnalyzer(SampleRate=cfgBPRF.SampleRate);
sa(waveBPRF);

Open Live Script

Generate random data for a PHY Service Data Unit (PSDU) payload. Create an IEEE 802.15.4a lrwpanHRPConfig object.

psdu = randi([0,1],50,1);
cfg4a = lrwpanHRPConfig(Mode='802.15.4a', ...
    Channel=9, ...            % High-band mandatory chan for code index 3
    MeanPRF=15.6, ...         % 8 candidate bursts
    DataRate=27.24, ...       % 1 chip per burst (PHR at 850 kbps max)
    CodeIndex=3, ...          % 3rd code with length 31 
    PreambleMeanPRF=4.03, ... % PreambleSpreadingFactor = 64
    PSDULength=100);          % PSDU length in bytes

Generate an 4a IEEE 802.15.4z waveform by using the lrwpanWaveformGenerator function and cfg4a configuration object. The waveform generator loops input PSDU payload bits as needed to fill PSDU length. Display the waveform by using a spectrumAnalyzer object.

wave4a = lrwpanWaveformGenerator(psdu,cfg4a);
sa = spectrumAnalyzer(SampleRate=cfg4a.SampleRate);
sa(wave4a);

Open Live Script

Generate random data for a PHY Service Data Unit (PSDU) payload. Create a BPRF IEEE 802.15.4z lrwpanHRPConfig object. BPRF payload data rate is always at 6.81 Mbps.

psdu = randi([0,1],8*100,1);
cfgBPRF = lrwpanHRPConfig(Mode='BPRF', ...
    STSPacketConfiguration=0, ... % Turn off STS
    PHRDataRate=6.81, ...         % PSDU header data rate in Mbps
    CodeIndex=9, ...              % A 127-symbols long SYNC code
    PSDULength=length(psdu)/8);   % PSDU length in bytes

Generate a multiframe BPRF IEEE 802.15.4z waveform by using the lrwpanWaveformGenerator function and cfgBPRF configuration object. The waveform generator loops PSDU length as needed to use all input PSDU payload bits. Display the waveform by using a timescope object.

waveBPRF = lrwpanWaveformGenerator(psdu,cfgBPRF, ...
    NumPackets=3, ...
    IdleTime=1e-4);
ts = timescope(SampleRate=cfgBPRF.SampleRate, ...
    TimeSpanSource="property", ...
    TimeSpan=length(waveBPRF)/cfgBPRF.SampleRate, ...
    YLimits=1.1*[min(waveBPRF), max(waveBPRF)]);
ts(waveBPRF);

Input Arguments

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Information bits, specified as a binary-valued column vector. Each transmission packet uses (cfg.PSDULength×8) bits from data. The function loops on data as needed to generate the requested number of packets, NumPackets. If the number of bits required for all generated packets exceeds the length of data, the data vector is looped as needed to generate the requested waveform. Looping on the bits allows you to define a short pattern, such as [1; 0; 0; 1], that repeats as the input to the PSDU coding across packets.

Data Types: double | int8
Complex Number Support: Yes

Packet format configuration, specified as an lrwpanHRPConfig or lrwpanOQPSKConfig object. The type of object you specify determines the IEEE® 802.15.4™ format of the output waveform, wave. The properties of the packet format configuration object determine the data rate and PSDU length of generated PPDUs.

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: NumPackets=21,IdleTime=15e-6

Number of packets to generate in a single function call, specified as a positive integer.

Idle time added after each packet in seconds, specified as a nonnegative scalar.

Output Arguments

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Packetized waveform, returned as a column vector. wave contains one or more packets of the same PPDU format. Each packet can contain different information bits. For more information, see IEEE 802.15.4 PPDU Format.

Data Types: double
Complex Number Support: Yes

HRP signal before pulse shaping, returned as a column vector of ternary values, specifically [-1, 0, 1]. symbols contains the modulated (symbol mapped) signal after preamble insertion.

Dependencies

This output applies when the input configuration object, cfg, is an lrwpanHRPConfig object.

Data Types: double
Complex Number Support: Yes

More About

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IEEE 802.15.4 PPDU Format

The IEEE standards for low-rate wireless networks, [1] and [2], specify IEEE 802.15.4 PHY protocol data unit (PPDU) formats for transmission of O-QPSK PHY and HRP UWB PHY waveforms. For all formats, the PPDU field structure includes preamble and payload portions. This figure shows the PPDU headers and payloads as defined in Figure 5-7 of [1].

PPDU format showing SHR, PHR, and PSDU

  • The lrwpanHRPConfig object specifies configuration for the HRP UWB PPDU format — The output waveform is a high-rate pulse repetition frequency (HRP) ultra-wide band (UWB) IEEE 802.15.4 a/z waveform. If the Mode property of the object is:

    • 'HPRF' — The output is a higher pulse repetition frequency (HPRF) waveform.

    • 'BPRF' — The output is a base pulse repetition frequency (BPRF) waveform.

    • '802.15.4a' — The output is an IEEE 802.15.4a™ waveform.

  • The lrwpanOQPSKConfig object specifies configuration for the O-QPSK PPDU format — The output waveform is a ZigBee® O-QPSK IEEE 802.15.4 waveform.

Waveform Looping

To produce a continuous input stream, you can have your code loop on a waveform from the last packet back to the first packet.

Looping from last signal packet to first signal packet to create a continuous input stream.

When looping a waveform, the last symbol of packet_N is followed by the first symbol of packet_1. If the waveform has only one packet, the waveform loops from the last symbol of the packet to the first symbol of the same packet.

Specify the idle time by using the IdleTime input to the lrwpanWaveformGenerator function.

References

[1] IEEE STD 802.15.4-2020. "IEEE Standard for Low-Rate Wireless Networks." May 2020.

[2] IEEE STD 802.15.4z-2020. "IEEE Standard for Low-Rate Wireless Networks." Amendment 1: Enhanced Ultra Wideband (UWB) Physical Layers (PHYs) and Associated Ranging Techniques. June 2020.

Extended Capabilities

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

Version History

Introduced in R2023a

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See Also

Apps

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