wlanClosestReferenceSymbol

Find closest constellation points

Syntax

refSym = wlanClosestReferenceSymbol(sym,mod)

refSym = wlanClosestReferenceSymbol(sym,mod,phase)

refSym = wlanClosestReferenceSymbol(sym,cfg)

refSym = wlanClosestReferenceSymbol(sym,cfg,userNumber)

Description

refSym = wlanClosestReferenceSymbol(sym,mod) returns the constellation points closest to equalized symbols sym for modulation scheme mod.

refSym = wlanClosestReferenceSymbol(sym,mod,phase) returns the constellation points closest to the equalized symbols with counterclockwise rotation phase.

refSym = wlanClosestReferenceSymbol(sym,cfg) returns the constellation points closest to the equalized symbols for cfg, a configuration object that parameterizes a single-user (SU) transmission or a recovered high-efficiency (HE) transmission.

refSym = wlanClosestReferenceSymbol(sym,cfg,userNumber) returns the constellation points closest to the equalized symbols for the user specified by userNumber in a multiuser (MU) transmission and MU-format configuration object cfg.

Examples

Find Closest Reference Symbols for 64-QAM

Find the closest reference symbols to a received set of noisy symbols for 64-QAM.

Create a high-efficiency single-user-format (HE-SU-format) configuration object, specifying a modulation and coding scheme (MCS) with 64-QAM.

cfg = wlanHESUConfig('MCS',6);

Obtain the PSDU length.

psduLength = getPSDULength(cfg); 

Generate a waveform for a payload of randomly generated bits and the specified configuration.

bits = randi([0 1],8*psduLength,1,'int8');
waveform = wlanWaveformGenerator(bits,cfg);

Generate noise to be added to the signal, specifying the signal-to-noise ratio (SNR).

SNR = 10;
rxWaveform = awgn(waveform,SNR);

Get the field indices and extract the HE-Data field.

ind =  wlanFieldIndices(cfg);
sym = rxWaveform(ind.HEData(1):ind.HEData(2));

Find the closest reference symbols for the specified modulation scheme.

mod = '64QAM';
refSym = wlanClosestReferenceSymbol(sym,mod);

Find Nearest Reference Symbols for DMG-Format Configuration

Find the closest reference symbols to a received set of noisy symbols in a DMG-format configuration.

Create a DMG-format configuration object, specifying the MCS.

cfg = wlanDMGConfig('MCS',10);

Generate a waveform for a payload of randomly generated bits and the specified configuration.

bits = randi([0 1],8*cfg.PSDULength,1,'int8');
waveform = wlanWaveformGenerator(bits,cfg);

Generate noise to be added to the signal, specifying the SNR.

SNR = 10;
rxWaveform = awgn(waveform,SNR);

Get the field indices and extract the DMG-Data field.

ind =  wlanFieldIndices(cfg);
sym = rxWaveform(ind.DMGData(1):ind.DMGData(2));

Find the closest reference symbols for the specified configuration.

refSym = wlanClosestReferenceSymbol(sym,cfg);

Input Arguments

sym — Equalized symbols

complex-valued array

Equalized symbols, specified as a complex-valued array.

Data Types: double
Complex Number Support: Yes

mod — Modulation scheme

'BPSK' | 'pi/2-BPSK' | 'QPSK' | 'pi/2-QPSK' | '16QAM' | 'pi/2-16QAM' | '64QAM' | 'pi/2-64QAM' | '256QAM' | '1024QAM' | '4096QAM'

Modulation scheme, specified as one of these values:

• 'BPSK' — Binary phase-shift keying (BPSK)

• 'pi/2-BPSK' — π/2-BPSK

• 'QPSK' — Quadrature phase-shift keying (QPSK)

• 'pi/2-QPSK' — π/2-QPSK

• '16QAM' — 16-point quadrature amplitude modulation (16-QAM)

• 'pi/2-16QAM' — π/2-16-QAM

• '64QAM' — 64-QAM

• 'pi/2-64QAM' — π/2-64-QAM

• '256QAM' — 256-QAM

• '1024QAM' — 1024-QAM

• '4096QAM' — 4096-QAM

Data Types: char | string

phase — Counterclockwise rotation

real-valued scalar (default) | real-valued row vector

Counterclockwise rotation, in radians, specified as a real-valued scalar or real-valued row vector. To return reference symbols for different phases, specify phase as a row vector in which each element represents a chosen phase.

Note

The rotations you specify in phase apply only to the constellation points returned in refSym, and not to the equalized symbols specified in sym.

Data Types: double

cfg — PHY format configuration

wlanHESUConfig object | wlanHEMUConfig object | wlanHERecoveryConfig object | wlanHETBConfig object | wlanVHTConfig object | wlanHTConfig object | wlanNonHTConfig object | wlanDMGConfig object | wlanS1GConfig object

Physical layer (PHY) format configuration, specified as one of these objects: wlanHESUConfig, wlanHEMUConfig, wlanHERecoveryConfig, wlanHETBConfig, wlanVHTConfig, wlanHTConfig, wlanNonHTConfig, wlanDMGConfig, or wlanS1GConfig.

userNumber — Number assigned to user of interest

positive integer

Number assigned to user of interest, specified as a positive integer in the interval [1, N_u], where N_u is the number users in the transmission.

This argument is required when you specify the cfg input as an object of type wlanHEMUConfig, wlanS1GConfig, or wlanVHTConfig.

If cfg is a wlanHEMUConfig object, N_u is equal to the number of elements in the value of its User property. If cfg is a wlanS1GConfig or wlanVHTConfig object, N_u is equal to the value of its NumUsers.

Dependencies

This argument applies only when the cfg input is an object of type wlanHEMUConfig, wlanS1GConfig, or wlanVHTConfig.

Data Types: double

Output Arguments

refSym — Constellation points closest to input symbols

complex-valued column vector

Constellation points closest to input symbols, returned as a complex-valued column vector. Each entry of refSym is the constellation point closest to the corresponding entry of the sym input; refSym is the same size as sym.

Data Types: double
Complex Number Support: Yes

Extended Capabilities

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

Version History

Introduced in R2019a