How to implement X410 four-channel full-bandwidth streaming application based on LabVIEW environment?

When using the USRP X410, many users hope to achieve four channels full-bandwidth IQ streaming and processing in applications. However, due to the data rate limitations of the PXIe Gen3 interface, this is currently difficult to achieve. Another method is to use the QSPF28 digital interface to transmit the IQ sample stream to the PXIe-7903 for FPGA co-processing. However, this brings the technical challenge of high-speed Aurora data flow control. How can this challenge be solved and a demonstration example that can be run immediately be provided? The following will introduce you to how to use the LabVIEW environment to make the USRP X410 and PXIe-7903 work together and achieve a four-channels full-bandwidth streaming example for your reference;

1. Hardware List

1 pcs * PXIe-8881

1 pcs * PXIe-1095

2pcs * PXIe-5841 (Optional, VST is only used for verification convenience and is not required for data volume)

1 pcs * X410 (P/N:787272-01)

1pcs * PXIe-7903 (P/N:788917-01)

1pcs * zHD to QSFP28 cable (P/N 788928)

RF Cable SMA to SMA Several

2. Software Driver

LabVIEW 2022 Q3+

LabVIEW FPGA 2022 Q3+

· NI-RFSA 23Q4, NI-RFSG 23Q4, NI-RFSG Playback Library 23Q4

NI-RFmx NR/SpecAn 23Q4

NI-USRP 2023 Q3

· NI-RFSA/NI-RFSG Instrument Driver for MGT Streaming 2023Q4

· FlexRIO with Integrated I/O 2024 Q2

· FlexRIO with Modular I/O 2024 Q2

· LabVIEW Instrument Design Libraries for High-Speed Serial Instruments

3. Hardware Setup

The connection diagram is as follows:

3.1 Connect the 10MHz reference clock output on the PXI chassis backplane to the reference clock input on the X410. Alternatively, use the 10MHz reference clock from Octo-Clock (CDA-2990).

3.2 Connect 7903 Port 2 to X410 QSFP28 Port 0.

3.3 As shown in the figure above, connect the RF OUT/RF IN of the two VST PXIe-5841s to RX2/TX1 of Channel 0/2 of the X410; and connect TX1 and RX2 of Channel 1/3 of the X410 with a cable.

4. Open the LabVIEW example and set the corresponding parameters;

4.1 Select the appropriate CLIP file

X410 QSFP28 includes the following two CLIP files:

a. 50G/80G port speed: streaming mode, flow control, big endian mode

b. 50G/100G port speed: Stream mode (no flow control), Big Endian mode. (Note that these two are native CLIPs included with the USRP driver.)

The PXIe-7903 12-port module also provides two CLIP files:

a. 50G/80G port speed: Stream mode, native flow control, big endian mode

b. 100G port speed: Stream mode (no flow control), Big Endian mode

The example introduced here is based on the verification of the 80G version of the CLIP file;

4.2 Set the necessary parameters:

As shown in the figure below, set the basic parameters related to X410 and PXIe-7903, such as Device Name, center frequency, antenna port, etc.

4.3 To better verify the streaming results, you could add the VST PXIe-5841 as a Signal Generator and Signal Analyzer to send NR signals to the X410 and analyze the streaming data received by the X410. Therefore, you need to set the relevant PXIe-5841 parameters in Instrument Studio, such as center frequency, power level, reference level, etc.

4.4 The basic data flow diagram of the Demo design is as follows

Click the RF OUT button (Instrument Studio panel) to send the signal, run the X410 and PXIe-7903 examples, and finally view the measurement results on the RFSA side in Instrument Studio.

Example 1. Demo 7903 Loopback and MRA_4Ch_80G (Host).vi, as shown below:

From the example results above, you can see that the throughput reaches 62.91456 Gbps, reaching the theoretical peak rate (i.e. 4 ports 491.32 32 bits = 62.91456 Gbps).

In this example, the X410 acts as a pure RF front-end, determining and controlling the data throughput of the Aurora transmission.
• QSFP28 0 port implements 80Gbps throughput interface with flow control
•Simultaneous acquisition of 4 channels at a sampling rate of 491.52MS/s and forwarding to the Aurora Tx channel
• Get signal data from the Aurora Rx channel and generate 4 channels of transmit signals, each channel has a rate of 491.52MS/s
• Real-time monitoring and reporting of Aurora port and RF port status

PXIe-7903 acts as a coprocessor
• 80Gbps throughput Aurora interface with flow control implemented on port 2
• Take the signal on the Aurora Rx channel and loop it directly back to the Aurora Tx channel
• Includes an MRA (Multiple Record Acquisition) engine that acquires 4 channels per request and performs analysis on the host
• Monitor and report the status of Aurora ports

Example 2: Demo 7903 WfmGen and MRA_4Ch_80G (Host).vi, as shown below:

The above example shows that data is generated from the 7903 and sent to the X410. The X410 uses Aurora's flow control capabilities to reversely control the data generation speed of the 7903.

Among them, X410 acts as a pure RF front end
• QSFP28 0 port implements 80Gbps throughput interface with flow control
• Collect 4Ch signals at 491.52MS/s and forward them to Aurora Tx channel
• Get signal data from Aurora Rx channel and generate 4Ch signal at 491.52MS/s
• Monitor and report the status of Aurora ports and RF ports

The PXIe-7903 acts as a waveform generator and coprocessor
• 80Gbps throughput Aurora interface with flow control implemented on port 2
• WaveGen on the 7903 can generate four channels of signals and send them over the Aurora link
• Acquire signals on Aurora Rx channels and MRA 4 channels per request and analyze them on the host
• Monitor and report the status of Aurora ports

Note: The above examples are all based on a four-channel streaming application on an X410. The current LabVIEW examples can also support related applications on multiple X410s. If necessary, please consult the relevant NI technical department for active support.