basebandTransceiver

Configure SDR as baseband transceiver

Since R2022a

Add-On Required: This feature requires the Wireless Testbench™ Support Package for NI™ USRP™ Radios add-on.

Description

Use the basebandTransceiver object to configure the specified software-defined radio (SDR) as a baseband transceiver to simultaneously transmit and capture IQ waveforms over the air.

This diagram shows a conceptual overview of capturing and transmitting radio signals in Wireless Testbench™ using a radio that you configure with this object. The onboard data buffering ensures contiguous data capture and transmit. The transmission controller enables you to specify continuous or single-shot transmissions.

Creation

Syntax

bbtrx = basebandTransceiver(radio)

bbtrx = basebandTransceiver(radio,Name=Value)

Description

bbtrx = basebandTransceiver(radio) creates a baseband transceiver object for the specified radio radio.

Note

The object requires exclusive access to radio hardware resources. Before creating this object, clear any existing Wireless Testbench object associated with the specified radio from the workspace.

bbtrx = basebandTransceiver(radio,Name=Value) sets properties using one or more name-value arguments. For example, CaptureDataType="double" sets the data type of the returned captured data to double.

Input Arguments

radio — Radio setup configuration

string scalar

Radio setup configuration, specified as a string scalar. To create a radio setup configuration, set up your radio and save your radio setup configuration using the Radio Setup wizard. To list all saved radio setup configurations, call the radioConfigurations function.

For a list of supported radios, see Supported Radio Devices.

Example: "MyRadio" indicates that you saved a radio setup configuration under the name MyRadio in the Radio Setup wizard.

Properties

TransmitCenterFrequency — Transmit center frequency in Hz

2.4e9 (default) | positive numeric scalar | numeric array

Transmit center frequency in Hz, specified as a one of these options.

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna in the TransmitAntennas property.

• Numeric array — The object applies the ith array element value to the ith antenna in the TransmitAntennas property.

The valid center frequency range depends on the radio device.

Radio Device	Center Frequency
USRP™ N300	1 MHz to 6 GHz
USRP N310	1 MHz to 6 GHz
USRP N320	1 MHz to 6 GHz
USRP N321	1 MHz to 6 GHz
USRP X300	10 MHz to 6 GHz
USRP X310	10 MHz to 6 GHz
USRP X410	1 MHz to 8 GHz

Note

When setting this property for multiple antennas on a USRP N300 or USRP N310 radio, consider these hardware characteristics.

• The antenna ports on the RF0 and RF1 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF0:TX/RX" and "RF1:TX/RX".

• The antenna ports on the RF2 and RF3 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF2:TX/RX" and "RF3:TX/RX". These antennas are available only on a USRP N310 radio.

TransmitAntennas — Transmit radio antenna

string scalar | string array

Transmit radio antenna, specified as one of these options.

• String constant — Specifies single antenna use.

• String array — Specifies multiple antenna use. (since R2024b)

Use this table to identify the supported radio antenna ports on your radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP N300	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP N310	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
	RF2 channel: TX/RX port	"RF2:TX/RX"
	RF3 channel: TX/RX port	"RF3:TX/RX"
USRP N320	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP N321	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP X300	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP X310	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP X410	DB0 RF0 channel: TX/RX 0 port	"DB0:RF0:TX/RX0" (default)
	DB0 RF1 channel: TX/RX 0 port	"DB0:RF1:TX/RX0"
	DB1 RF0 channel: TX/RX 0 port	"DB1:RF0:TX/RX0"
	DB1 RF1 channel: TX/RX 0 port	"DB1:RF1:TX/RX0"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the TransmitAntennas and CaptureAntennas properties.

Radio Device	Maximum Number of Antennas
USRP N300	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X300	2
USRP X310	2
USRP X410	4

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Example: TransmitAntennas=["RF0:TX/RX","RF1:TX/RX"] specifies two transmit antennas.

Data Types: string

TransmitRadioGain — Transmit radio gain in dB

10 (default) | positive numeric scalar | numeric array

Transmit radio gain in dB, specified as one of these options.

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna that you specify in the TransmitAntennas property.

• Numeric array — The object applies the ith array element value to the ith antenna in the TransmitAntennas property.

The valid gain range depends on the radio device.

Radio Device	Transmit Radio Gain
USRP N300	0 dB to 65 dB
USRP N310	0 dB to 65 dB
USRP N320	0 dB to 60 dB
USRP N321	0 dB to 60 dB
USRP X300	0 dB to 31.5 dB
USRP X310	0 dB to 31.5 dB
USRP X410	0 dB to 60 dB

Data Types: double

CaptureCenterFrequency — Capture center frequency in Hz

2.4e9 (default) | positive numeric scalar | numeric array

Capture center frequency in Hz, specified as one of these options.

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna in the CaptureAntennas property.

• Numeric array — The object applies the ith array element value to the ith antenna in the CaptureAntennas property.

The valid center frequency range depends on the radio device.

Radio Device	Center Frequency
USRP N300	1 MHz to 6 GHz
USRP N310	1 MHz to 6 GHz
USRP N320	1 MHz to 6 GHz
USRP N321	1 MHz to 6 GHz
USRP X300	10 MHz to 6 GHz
USRP X310	10 MHz to 6 GHz
USRP X410	1 MHz to 8 GHz

Note

When setting this property for multiple antennas on a USRP N300 or USRP N310 radio, consider these hardware characteristics.

• The antenna ports on the RF0 and RF1 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF0:RX2" and "RF1:RX2".

• The antenna ports on the RF2 and RF3 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF2:RX2" and "RF3:RX2". These antennas are available only on a USRP N310 radio.

Data Types: double

CaptureAntennas — Capture radio antenna

string scalar | string array

Capture radio antenna, specified as one of these options.

• String constant — Specifies single antenna use.

• String array — Specifies multiple antenna use. (since R2024b)

Use this table to identify the supported radio antenna ports on the radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP N300	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
USRP N310	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
	RF2 channel: RX2 port	"RF2:RX2"
	RF3 channel: RX2 port	"RF3:RX2"
USRP N320	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
USRP N321	RF0 channel: RX2 port	RF0 channel: RX2 port
	RF0 channel: RX2 port	RF0 channel: RX2 port
USRP X300	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP X310	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP X410	DB0 RF0 channel: RX 1 port	"DB0:RF0:RX1" (default)
	DB0 RF1 channel: RX 1 port	"DB0:RF1:RX1"
	DB1 RF0 channel: RX 1 port	"DB1:RF0:RX1"
	DB1 RF1 channel: RX 1 port	"DB1:RF1:RX1"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the CaptureAntennas and TransmitAntennas properties.

Radio Device	Maximum Number of Antennas
USRP N300	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X300	2
USRP X310	2
USRP X410	4

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Example: CaptureAntennas=["RF0:RX2","RF1:RX2"] specifies two capture antennas.

Data Types: string

CaptureRadioGain — Capture radio gain in dB

10 (default) | positive numeric scalar | numeric array

Capture radio gain in dB, specified as one of these options.

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna in the CaptureAntennas property.

• Numeric array — The object applies the ith array element value to the ith antenna in the CaptureAntennas property.

The valid gain range depends on the radio device.

Radio Device	Capture Radio Gain
USRP N300	0 dB to 75 dB
USRP N310	0 dB to 75 dB
USRP N320	0 dB to 60 dB
USRP N321	0 dB to 60 dB
USRP X300	0 dB to 31.5 dB
USRP X310	0 dB to 31.5 dB
USRP X410	0 dB to 60 dB

Data Types: double

CaptureDataType — Data type of captured data

"int16" (default) | "double" | "single"

Data type of the captured data, specified as "int16", "double", or "single". Use this property to set the data type of the captured data that the capture object function returns.

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: string

SampleRate — Baseband sample rate in Hz

highest device sample rate (default) | positive numeric scalar

Baseband sample rate in Hz, specified as a positive numeric scalar. For more information on how the radio achieves the specified sample rate, see Baseband Sample Rate in NI USRP Radios.

The sample rate depends on the radio device.

Radio Device	Sample Rate
USRP N300	120,945 Hz to 76.8 MHz 122.88 MHz 125.00 MHz 153.60 MHz (default)
USRP N310
USRP N320	196,851 Hz to 125 MHz 200.00 MHz 245.76 MHz 250.00 MHz (default)
USRP N321
USRP X300	181,418 Hz to 100 MHz 184.32 MHz 200.00 MHz (default)
USRP X310
USRP X410	241,890 Hz to 125 MHz 245.76 MHz 250.00 MHz (default)

Note

To update this property, you must stop any ongoing transmission by calling the stopTransmission function on the object. When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: double

DroppedSamplesAction — Behavior upon dropped samples

"error" (default) | "warning" | "none"

Behavior of the capture object function upon dropped samples, specified as one of these values.

• "error" — The object function stops with an error message.

• "warning" — The object function displays a warning message.

• "none" — The object function ignores dropped samples.

Data Types: string

Object Functions

capture	Capture IQ data using baseband receiver or transceiver
transmit	Transmit waveform using baseband transmitter or transceiver
stopTransmission	Stop transmission from baseband transmitter or transceiver

Examples

Configure Baseband Transceiver to Transmit and Capture Data

Create a baseband transceiver object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

bbtrx = basebandTransceiver("MyRadio")

bbtrx = 
  basebandTransceiver with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           TransmitAntennas: "RF0:TX/RX"
           CaptureRadioGain: 10
     CaptureCenterFrequency: 2.4000e+09
            CaptureAntennas: "RF0:RX2"
            CaptureDataType: "int16"
       DroppedSamplesAction: "error"
                 SampleRate: 250000000

Set the baseband sample rate.

bbtrx.SampleRate = 122.88e6;

Set the transmit and capture center frequencies.

bbtrx.TransmitCenterFrequency = 2.2e9;
bbtrx.CaptureCenterFrequency = 2.2e9;

Generate random transmit waveform.

txWaveform = complex(randn(1000,1),randn(1000,1));

Transmit the generated waveform continuously with the radio associated with the baseband transceiver object using the default transmit antenna.

transmit(bbtrx,txWaveform,"continuous");

Capture IQ data with the radio associated with the baseband transceiver object using the default capture antenna.

[data,~] = capture(bbtrx,milliseconds(3));

Stop the continuous transmission after data capture is complete.

stopTransmission(bbtrx);

Transmit and Capture Data on Multiple Antennas with Baseband Transceiver

Create a baseband transceiver object, specifying a radio setup configuration previously saved in the Radio Setup wizard. Specify two transmit antennas and two capture antennas, each with a different center frequency.

bbtrx = basebandTransceiver("MyRadio", ...
    TransmitAntennas=["RF0:TX/RX","RF1:TX/RX"], ...
    TransmitCenterFrequency=[2.2e9,2.4e9], ...
    CaptureAntennas=["RF0:RX2","RF1:RX2"], ...
    CaptureCenterFrequency=[2.2e9,2.4e9])

bbtrx = 
  basebandTransceiver with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: [2.2000e+09 2.4000e+09]
           TransmitAntennas: ["RF0:TX/RX"    "RF1:TX/RX"]
           CaptureRadioGain: 10
     CaptureCenterFrequency: [2.2000e+09 2.4000e+09]
            CaptureAntennas: ["RF0:RX2"    "RF1:RX2"]
            CaptureDataType: "int16"
       DroppedSamplesAction: "error"
                 SampleRate: 153600000

Generate two random complex transmit waveforms with a length of 1000 samples.

length = 1000;
txWaveform = [complex(randn(length,1),randn(length,1)),...
    complex(randn(length,1),randn(length,1))];

Transmit the generated waveform continuously with the radio associated with the baseband transceiver object.

transmit(bbtrx,txWaveform,"continuous");

Capture IQ data with the radio associated with the baseband transceiver object.

[data,~] = capture(bbtrx,length);

The output data is a 1000 x 2 array. Each column contains the data captured on one antenna, in the order that they are specified.

Stop the continuous transmission when the capture is complete.

stopTransmission(bbtrx);

Tips

You cannot use save and load to store and reload Wireless Testbench objects. Instead, you can re-create the object with these steps:

1. Write code to create a basebandTransceiver object with a saved radio setup configuration radio and set the properties.

2. Save the code to a script.

3. Run the script in a new MATLAB^® session with the same saved radio setup configuration.

Version History

Introduced in R2022a

R2024b: Specify multiple transmit and capture antennas

You can now specify multiple antennas using the TransmitAntennas and CaptureAntennas properties. This enables you to transmit and capture IQ data on multiple antennas using the transmit and capture functions.