evdoForwardWaveformGenerator

Generate 1xEV-DO forward link waveform

Syntax

waveform = evdoForwardWaveformGenerator(cfg)

Description

waveform = evdoForwardWaveformGenerator(cfg) returns the 1xEV-DO forward link waveform as defined by the parameter configuration structure, cfg.

The top-level parameters and lower-level substructures of cfg specify the waveform and channel properties the function uses to generate a 1xEV-DO waveform. You can generate cfg by using the evdoForwardReferenceChannels function.

Note

The tables herein list the allowable values for the top-level parameters and substructure fields. However, not all parameter combinations are supported. To ensure that the input argument is valid, use the evdoForwardReferenceChannels function. If you input the structure fields manually, consult [1] to ensure that the input parameter combinations are permitted.

Examples

Generate 1xEV-DO Revision A Forward Link Waveform

Create a structure to transmit a Revision A 1xEV-DO channel consisting of three 1024-bit packets transmitted over 2 slots with a 64-bit preamble length.

config = evdoForwardReferenceChannels('RevA-1024-2-64',3);

Verify that the function created a 1-by-3 structure array. Each element in the structure array corresponds to a data packet.

config.PacketSequence

ans=1×3 struct array with fields:
    MACIndex
    PacketSize
    NumSlots
    PreambleLength

Examine the first structure element to verify the packet size, number of slots, and preamble length match what you specified in the function call.

config.PacketSequence(1)

ans = struct with fields:
          MACIndex: 0
        PacketSize: 1024
          NumSlots: 2
    PreambleLength: 64

Generate the waveform.

wv = evdoForwardWaveformGenerator(config);

Generate 1xEV-DO Forward Link Waveform with Custom Filter

Create a structure to generate two packets of a 1.8 Mbps Release 0 channel.

config = evdoForwardReferenceChannels("Rel0-1843200-1",2);

Calculate the sample rate of the waveform.

fs = 1.2288e6 * config.OversamplingRatio;

Disable the internal filter of the evdoForwardWaveformGenerator function. Generate the 1xEV-DO waveform.

config.FilterType = "off";
wv = evdoForwardWaveformGenerator(config);

sa = spectrumAnalyzer( ...
    SampleRate=fs, ...
    ChannelNames=["1xEv-DO","1xEV-DO filtered"]);

Create a lowpass FIR filter with a 500 kHz passband, a 750 kHz stopband, and a stopband attenuation of 60 dB.

d = designfilt("lowpassfir", ...
    PassbandFrequency=500e3, ...
    StopbandFrequency=750e3, ...
    StopbandAttenuation=60, ...
    SampleRate=fs);

Change the filter type to "Custom" and specify the coefficients from the digital filter, d.

config.FilterType = "Custom";
config.CustomFilterCoefficients = d.Coefficients;

Generate the waveform using the custom filter coefficients.

wvfiltered = evdoForwardWaveformGenerator(config);

Plot the spectrum of the unfiltered and filtered 1xEV-DO waveform. The filter attenuates the waveform by 60 dB for frequencies outside of $$\pm$$ 750 kHz.

sa(wv,wvfiltered)

Input Arguments

cfg — Configuration of the parameters and channels used by the waveform generator

structure

Configuration of the parameters and channels used by the waveform generator. The configuration structure is defined in these tables.

Top-Level Parameters and Substructures

Parameter Field	Values	Description
Release	'Release0' | 'RevisionA'	1xEV-DO
PNOffset	Nonnegative scalar integer [0, 511]	PN offset of the base station
IdleSlotsWithControl	'Off' | 'On'	Include idle slots with control channels
EnableControl	'Off' | 'On'	Enable control signaling
NumChips	Positive scalar integer	Number of chips in the waveform
OversamplingRatio	Positive scalar integer [1, 8]	Oversampling ratio at output
FilterType	'cdma2000Long' | 'cdma2000short' | 'Custom' | 'Off'	Select filter type or disable filtering
CustomFilterCoefficients	Real vector	Custom filter coefficients (applies when the FilterType field is set to 'Custom')
InvertQ	'Off' | 'On'	Negate the quadrature output
EnableModulation	'Off' | 'On'	Enable carrier modulation
ModulationFrequency	Nonnegative scalar integer	Carrier modulation frequency (applies when EnableModulation is 'On')
PacketSequence	Structure	See PacketSequence substructure.
PacketDataSources	Structure	See PacketDataSources substructure.

PacketSequence Substructure

Include the PacketSequence substructure in the cfg structure to define a sequence of data packets for consecutive transmission. The PacketSequence substructure contains these fields.

Parameter Field	Values	Description
MACIndex	Positive scalar integer	MAC index associated with the packet
Release 0
DataRate	38400 | 76800 | 153600 | 307200 | 614400 | 921600 | 1228800 | 1843200 | 2457600	Data rate (bps)
NumSlots	Positive scalar integer	Number of slots
Revision A
PacketSize	128 | 256 | 512 | 1024 | 2048 | 3072 | 4096 | 5120	Packet size (bits)
NumSlots	1 | 2 | 4 | 8 | 16	Number of slots
PreambleLength	64 | 128 | 256 | 512 | 1024	Preamble length (chips)

PacketDataSources Substructure

Include a PacketDataSources substructure in the cfg structure to define a set of matching data sources for each MAC index. The PacketDataSources substructure contains these fields.

Parameter Field	Values	Description
MACIndex	Positive scalar integer	MAC index associated with the packet
DataSource	Cell array, {'PN Type', RN Seed} or binary vector. Standard PN sequence options are 'PN9', 'PN15', 'PN23', 'PN9-ITU', and 'PN11'.	Data source. Specify a standard PN sequence with a random number seed or a custom vector.
EnableCoding	'Off' | 'On'	Enable error correction coding

Output Arguments

waveform — Modulated baseband waveform comprising the primary physical channels

complex vector array

Modulated baseband waveform comprising the primary cdma2000™ physical channels, returned as a complex vector array.

References

[1] 3GPP2 C.S0024–A v3.0. “cdma2000 High Rate Packet Data Air Interface Specification.” 3rd Generation Partnership Project 2.

Version History

Introduced in R2015b