info

Provide dimensioning information for OFDM modulator

Syntax

S = info(obj)

Description

S = info(obj) returns a structure with fields that identify the input and output signal dimensions for the comm.OFDMModulator System object™, obj.

Examples

Determine OFDM Modulator Data Dimensions

Get the OFDM modulator data dimensions by using the info object function.

Create an OFDM modulator object with pilot indices, a DC null, and two transmit antennas.

ofdmMod = comm.OFDMModulator( ...
    NumGuardBandCarriers=[4; 3], ...
    PilotInputPort=true, ...
    PilotCarrierIndices=cat(3,[12; 26; 40; 54],[11; 25; 39; 53]), ...
    InsertDCNull=true, ...
    NumTransmitAntennas=2);

Use the info object function to get the modulator input data, pilot input data, and output data sizes.

info(ofdmMod)

ans = struct with fields:
     DataInputSize: [48 1 2]
    PilotInputSize: [4 1 2]
        OutputSize: [80 2]

Input Arguments

obj — System object to return dimensional information for

comm.OFDMModulator

System object to return dimensional information for, specified as a comm.OFDMModulator System object.

Output Arguments

S — Dimensions for OFDM modulator signals

structure

Dimensions for OFDM modulator signals, returned as a structure with fields that identify the input and output signal dimensions for the comm.OFDMModulator System object, obj.

DataInputSize — Dimensions of input data signal

column vector

Dimensions of input data signal, returned as a column vector. The element values are computed as [N_DataSC,N_Sym,N_Streams], based on the configuration of the input obj.

For variable definitions, see List of Variables.

Data Types: double

PilotInputSize — Dimensions of pilot input signal

column vector

Dimensions of the pilot input signal, returned as a column vector. The element values are computed as [N_Pilot,N_Sym,N_Streams], based on the configuration of the input obj.

For variable definitions, see List of Variables.

Data Types: double

OutputSize — Modulator output dimensions

column vector

Modulator output signal matrix dimensions, returned as a column vector. The element values are computed as [N_Out,N_Streams], based on the configuration of the input obj.

For variable definitions, see List of Variables.

Data Types: double

Data Types: struct

More About

List of Variables

These variables describe the dimensions of the input and output signals for the comm.OFDMModulator System object.

Variable	Description
NDataSC	Number of data subcarriers, such that NDataSC = NFFT − NleftG − NrightG − NDCNull − NPilot − NCustNull.
NFFT	Number of subcarriers, obj.FFTLength.
NleftG and NrightG	Left and right guard bands specified by obj.NumGuardBandCarriers.
NDCNull	Number of DC null subcarriers specified as either 0 or 1, obj.InsertDCNull.
NPilot	Number of pilot subcarriers. When you set obj.PilotOutputPort to 1, NPilot = size(obj.PilotCarrierIndices,1). When you set obj.PilotOutputPort to 0, NPilot = 0 for the calculation of NDataSC. .
NCustNull	Number of subcarriers used for custom nulls. This variable applies only when the obj.PilotCarrierIndices is a 3D array.
NSym	Number of symbols, obj.NumSymbols.
NStreams	Number of transmit streams, obj.NumTransmitAntennnas.
NCP	Cyclic prefix length for each symbol. When obj.CyclicPrefixLength is a scalar, NCP = obj.CyclicPrefixLength.
NCPTotal	Total cyclic prefix length over all the symbols. When obj.CyclicPrefixLength is a row vector, NCPTotal = sum(obj.CyclicPrefixLength).
NOut	When obj.CyclicPrefixLength is a scalar, NOut = NSym × (NFFT + NCP). When obj.CyclicPrefixLength is a row vector, NOut = (NSym × NFFT) + NCPTotal.

Version History

Introduced in R2014a