dvbrcs2RecoveryConfig

Receiver configuration parameters for DVB-RCS2

Since R2021b

Description

The dvbrcs2RecoveryConfig object creates a Digital Video Broadcasting Second Generation Return Channel over Satellite (DVB-RCS2) recovery configuration object. Recover the frame protocol data unit (PDU) from the received DVB-RCS2 waveform by using object properties.

Creation

Syntax

cfgrcs2 = dvbrcs2RecoveryConfig

cfgrcs2 = dvbrcs2RecoveryConfig(Name,Value)

Description

cfgrcs2 = dvbrcs2RecoveryConfig creates a default DVB-RCS2 recovery configuration object.

cfgrcs2 = dvbrcs2RecoveryConfig(Name,Value) sets Properties using one or more name-value pairs. Enclose each property name in quotes. For example, dvbrcs2RecoveryConfig('IsCustomWaveform',true) recovers a custom DVB-RCS2 waveform with the specified property values.

Properties

TransmissionFormat — Transmission format

"TC-LM" (default) | "SS-TC-LM"

Transmission format, specified as one of these values.

• "TC-LM" — Turbo codes with linear modulation (TC-LM)

• "SS-TC-LM" — Spread spectrum turbo codes with linear modulation (SS-TC-LM)

Data Types: char | string

ContentType — Frame PDU burst content type

"traffic" (default) | "logon" | "control"

Frame protocol data unit (PDU) burst content type, specified as "traffic", "logon", or "control".

Data Types: char | string

IsCustomWaveform — Custom waveform indicator

0 or false (default) | 1 or true

Custom waveform indicator, specified as one of these values.

• 0 (false) — Use this option to demodulate the complex in-phase quadrature (IQ) samples from a standard-defined reference waveform.

• 1 (true) — Use this option to demodulate the complex IQ samples from a custom waveform.

Data Types: logical

WaveformID — Reference waveform ID

1 (default) | positive integer

Reference waveform ID, specified as one of these options.

• Integer in the range [1, 22] or [32, 49] — Use this option when you set the TransmissionFormat property to "TC-LM".

• Integer in the range [1, 19] — Use this option when you set the TransmissionFormat property to "SS-TC-LM".

Based on the values set for TransmissionFormat and WaveformID properties, this object considers the receiver parameters according to ETSI EN 301 545-2 Annex A Table A-1 and A-2 [1].

Dependencies

To enable this property, set the IsCustomWaveform property to false.

Data Types: double | unit8

SpreadingFactor — Spreading factor

2 (default) | integer in the range [2, 16]

Spreading factor, specified as an integer in the range [2, 16].

Dependencies

To enable this property, set the TransmissionFormat property to "SS-TC-LM" and the IsCustomWaveform property to true.

Data Types: double

BurstLength — Burst length

256 (default) | integer in the range [7, 25,233,405]

Burst length, specified as an integer in the range [7, 25,233,405]. This length includes the preamble, postamble, and pilot sum, in addition to the payload symbols.

When you set the TransmissionFormat property to "TC-LM", the unit of burst length is symbols. When you set the TransmissionFormat property to "SS-TC-LM", the unit of burst length is chips.

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: double

MappingScheme — Mapping scheme

"pi/2-BPSK" (default) | "QPSK" | "8PSK" | "16QAM"

Mapping scheme, specified as one of these values.

• "pi/2-BPSK"

• "QPSK"

• "8PSK"

• "16QAM"

Dependencies

To enable this property, set the TransmissionFormat property to "TC-LM" and the IsCustomWaveform property to true.

Note

When you set the TransmissionFormat property to "SS-TC-LM", the only valid value of MappingScheme is "pi/2-BPSK".

Data Types: char | string

CodeRate — Code rate

"1/3" (default) | "1/2" | "2/3" | "3/4" | "4/5" | "5/6" | "6/7" | "7/8"

Code rate, specified as one of these values.

• "2/3", "3/4", "4/5", "5/6", "6/7", or "7/8" — Use one of these values when you set the MappingScheme property to "8PSK".

• "3/4", "4/5", "5/6", "6/7", or "7/8" — Use one of these values when you set the MappingScheme property to "16QAM".

All code rates are applicable if MappingScheme property is set to "pi/2-BPSK" or "QPSK".

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: char | string

PermutationParameters — Permutation control parameters

[9 0 0 0 0] (default) | vector

Permutation control parameters that the dvbrcs2RecoveryConfig uses to generate turbo encoder interleaver indices, specified as a five-element vector in order: P, Q₀, Q₁, Q₂, and Q₃. P must be in the range [9, 255], and Q₀, Q₁, Q₂, and Q₃ must be in the range [0, 15].

To generate unique interleaver indices, the value of P must be co-prime to PayloadLengthInBytes*4.

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: double

PreambleLength — Preamble length

8 (default) | integer in the range [0, 255]

Preamble length, specified as an integer in the range [0, 255].

When you set the TransmissionFormat property to "TC-LM", the unit of preamble length is symbols. When you set the TransmissionFormat property to "SS-TC-LM", the unit of preamble length is chips.

A preamble of this specified length is prefixed to the payload symbols.

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: double

PostambleLength — Postamble length

8 (default) | integer in the range [0, 255]

Postamble length, specified as an integer in the range [0, 255].

When you set the TransmissionFormat property to "TC-LM", the unit of postamble length is symbols. When you set the TransmissionFormat property to "SS-TC-LM", the unit of postamble length is chips.

A postamble of this specified length is suffixed to the payload symbols in the burst sequence.

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: double

PilotPeriod — Pilot period

0 (default) | integer in the range [0, 4095]

Pilot period, specified as an integer in the range [0, 4095]. A value of 0 indicates no pilots are inserted.

When you set the TransmissionFormat property to "TC-LM", the unit of pilot period is symbols. When you set the TransmissionFormat property to "SS-TC-LM", the unit of pilot period is chips.

The pilot period represents the length of the sequence from first symbol of a pilot block to the first symbol of the next pilot block in symbols or chips.

Dependencies

To enable this property, set the IsCustomWaveform property to true.

Data Types: double

PilotBlockLength — Pilot block length

1 (default) | integer in the range [1, 255]

Pilot block length, specified as an integer in the range [1, 255].

After every PilotPeriod symbols or chips, a pilot block of this specified length is detected, which must be removed to recover the payload symbols.

Dependencies

To enable this property, set the IsCustomWaveform property to true and PilotPeriod property to a positive integer.

Data Types: double

PilotSum — Total pilot symbols or chips in received waveform

0 (default) | nonnegative integer

Total pilot symbols or chips in the received waveform, specified as one of these options.

• Integer in the range [0, 255] — Use this option when you set the TransmissionFormat property to "TC-LM".

• Integer in the range [0, 65,535] — Use this option when you set the TransmissionFormat property to "SS-TC-LM".

When you set the TransmissionFormat property to "TC-LM", the unit of pilot sum is symbols. When you set the TransmissionFormat property to "SS-TC-LM", the unit of pilot sum is chips.

Dependencies

To enable this property, set the IsCustomWaveform property to true and PilotPeriod property to a positive integer.

Data Types: double

ScramblingPolynomial — Scrambling polynomial

16-bit zero vector (default) | 16-bit vector of binary values | numeric vector

Scrambling polynomial, specified as one of these options.

• 16-bit vector of binary values from the most significant bit (MSB), z¹⁶, to least significant bit (LSB), z¹. Each element of this vector corresponds to the coefficient of z and its exponent, specified from MSB to LSB. For details on the binary representation, see ETSI EN 301 545-2 Section 7.3.7.1.5.

• Numeric vector containing the exponents of z for nonzero terms of the polynomial in descending order.

The scrambling polynomial determines the shift register feedback connection to generate the spreading sequence.

The coefficient of z⁰ is always 1.

The default value of this scrambling polynomial indicates the default scrambling sequence provided in the standard. When you set the TransmissionFormat property to "SS-TC-LM" and the IsCustomWaveform property to false, the default scrambling sequence is used to descramble the received reference waveform.

Dependencies

To enable this property, set the TransmissionFormat property to "SS-TC-LM" and the IsCustomWaveform property to true.

Data Types: double | logical

ScramblingInitialConditions — Scrambling initial conditions

[1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] (default) | 1 | 16-bit vector of binary values

Scrambling initial conditions of the shift register, specified as one of these options.

• 1 — Use this option to set the initial condition of each cell of the shift register to this value.

• 16-bit vector of binary values from the MSB (z¹⁶) to LSB (z¹) — Use this option to set the initial condition of each cell of the shift register to the corresponding element in this vector.

Dependencies

To enable this property, set the TransmissionFormat property to "SS-TC-LM" and the ScramblingPolynomial property to a value other than the default value.

Data Types: double | logical

NumDecodingIterations — Number of decoding iterations

8 (default) | positive integer

Number of decoding iterations of the DVB-RCS2 turbo decoder, specified as a positive integer.

Data Types: double

PayloadLengthInBytes — Payload length in bytes

10 (default) | positive integer

This property is read-only.

Payload length in bytes, returned as a positive integer. This length represents the DVB-RCS2 turbo decoder output length.

Use this property output to choose a valid value for the first element of PermutationParameters property (that is, P).

PayloadLengthInBytes*4 and P must be co-primes.

Data Types: double

Object Functions

Specific to This Object

dvbrcs2BitRecover

Recover bits for DVB-RCS2 waveform

Examples

Create DVB-RCS2 Receiver Object

Create a DVB-RCS2 recovery configuration object.

Create and then set the properties of the object.

cfgrcs2 = dvbrcs2RecoveryConfig;
cfgrcs2.TransmissionFormat = "SS-TC-LM";
cfgrcs2.ContentType = "control";
cfgrcs2.WaveformID = 20;
cfgrcs2.NumDecodingIterations = 6;

Display the properties of the DVB-RCS2 object.

disp(cfgrcs2)

  dvbrcs2RecoveryConfig with properties:

       TransmissionFormat: "SS-TC-LM"
              ContentType: "control"
         IsCustomWaveform: 0
               WaveformID: 20

   Coding and Modulation:
    NumDecodingIterations: 6

Recover PDU from DVB-RCS2 Reference Waveform

Recover the frame PDU for a DVB-RCS2 reference waveform.

Set the properties of a DVB-RCS2 waveform generator System object™.

wg = dvbrcs2WaveformGenerator;
wg.TransmissionFormat = "SS-TC-LM";
wg.WaveformID = 7;
wg.SamplesPerSymbol = 2;

Generate a frame PDU.

framePDU = randi([0 1],wg.FramePDULength,1);

Generate the DVB-RCS2-based burst symbols.

txWaveform = wg(framePDU);

Add additive white Gaussian noise (AWGN) to the generated waveform.

sps = wg.SamplesPerSymbol; 
EsNodB = 1;
snrdB = EsNodB - 10*log10(sps);
rxIn = awgn(txWaveform,snrdB,"measured");

Create and then configure the DVB-RCS2 recovery configuration object.

cfg = dvbrcs2RecoveryConfig;
cfg.TransmissionFormat = wg.TransmissionFormat;
cfg.WaveformID = wg.WaveformID;

Create a raised cosine receiver filter.

rxFilter = comm.RaisedCosineReceiveFilter( ...
                 'RolloffFactor',0.2, ...
                 'InputSamplesPerSymbol',sps, ...
                 'DecimationFactor',sps);
span = rxFilter.FilterSpanInSymbols;

Apply matched filtering and remove the filter delay.

filtOut = rxFilter([rxIn; ...
               complex(zeros(span/2*sps,1))]);
rxSymb = filtOut(span+1:end);

Recover user packets. Display the frame PDU cyclic redundancy check (CRC) status and the numbers of bit errors.

[rxOut,pduErr] = dvbrcs2BitRecover(rxSymb,cfg,10^(-EsNodB/10));
fprintf("Erroneous frame PDU = %d\n", pduErr)

Erroneous frame PDU = 0

fprintf("Number of bit errors = %d\n", sum(framePDU~=rxOut))

Number of bit errors = 0

References

[1] ETSI Standard EN 301 545-2 V1.2.1(2014-11). Digital Video Broadcasting (DVB); Second Generation Interactive Satellite Systems (DVB-RCS2); Part 2: Lower Layers for Satellite Standard.

Extended Capabilities

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

Version History

Introduced in R2021b