The mmWave Transceiver System is an SDR platform for building mmWave applications including system prototyping. It gives users access to a flexible hardware platform and application software that enables real-time over the air mmWave communications research. The software is open to the user and can be modified as research needs change so designed can be iterated and optimized to meet specific goals or objectives.
The NI mmWave transceiver system is comprised of PXIe chassis, controllers, a clock distribution module, FlexRIO FPGA modules, high speed DACs, high speed ADCs, LO and IF modules, and mmWave radio heads. The modules can be assembled in various configurations to address a large number of mmWave applications ranging from channel sounding to MIMO communications link prototyping. This document provides a detailed overview of the hardware that is used in the mmWave transceiver system and how modules interact with each other. Detailed performance specifications for the system can be found in the mmWave transceiver system specifications sheet and model page.
PXI Express Chassis
The mmWave prototyping system is based on the PXIe-1085 chassis. The chassis houses the different processing modules and provides power supply, interconnectivity and timing and synchronization infrastructure. This 18 slot chassis features PCI Express (PCIe) Generation 3 technologies in every slot for high-throughput, low-latency applications. The chassis is capable of 4 GB/s of per-slot bandwidth and 24 GB/s of system bandwidth. The PXIe-1085 uses a dual-switch backplane architecture, shown in the system diagram of Figure 3. Because of the flexible design of PXI, multiple chassis can be daisy-chained together or put in a star configuration when building higher channel-count systems.

Figure 3: 180Slot PXIe-1085 Chassis (a) and System Diagram (b)
High-Performance Reconfigurable FPGA Processing Module
Central to all SDRs is the software and computational elements that compose the physical layer. The mmWave prototyping system uses single slot FPGA modules to add flexible, high-performance processing modules, programmable with LabVIEW, within the PXIe form factor. The PXIe-7976R FlexRIO FPGA module can be used standalone, providing a large and customizable Xilinx Kintex-7 410T with PCI Express Generation 2x8 connectivity to the PXI Express backplane. The mmWave transceiver system maps the different processing tasks to multiple FPGAs, depending on the particular configuration in a software configurable manner.

Figure 4: PXIe-7976R FlexRIO Module (a) and System Diagram (b)
High performance FPGA for high data throughput applications
The NI PXIe-7902 FPGA module is powerful processing module built with a Xilinx Virtex 7 485T. The large FPGA makes it ideal for processing heavy applications such as the mmWave physical layer. This module can transfer data across the backplane of a PXIe chassis with PCIe gen 2x8 speeds. For applications needing to support faster data rates, the PXIe-7902 also features 6 miniSAS HD front panel connectors composed of 24 Multi Gigabit Transceivers (MGTs). The MGTs can be connected to other PXIe-7902 modules or to other modules such as a DAC or ADC to enable up to 2 GHz of real-time bandwidth on multi-channel baseband signals.

Figure 5: PXIe-7902R FPGA module (a) and System Diagram (b)
Ultra wideband DAC and ADC
The PXIe-3610 DAC is shown below in Figure 6, and the PXIe-3630 ADC is shown in Figure 7. They provide access to analog baseband differential I/Q pairs through 4 MCX front panel connectors. These modules can be connected together to create a baseband loopback test system, connected to the PXIe-3620 IF module, or to 3rd party baseband hardware. Basic performance information is shown below in Table 1. Detailed performance information can be found in the mmWave transceiver system data sheet.

Table 1: Basic performance specifications of the PXIe-3610 and PXIe-3630

Figure 6: DAC module and block diagram

Figure 7: ADC module and block diagram
IF module
The PXIe-3620 LO/IF module is capable of processing one transmit and one receive chain for up to 2 GHz of bandwidth each. The NI PXIe-3620 mixes the input signals with the integrated LO to upconvert the baseband signal to a software programmable IF between 8.5 – 13 GHz. For receive, the NI PXIe-3620 takes an 8.5 to 13 GHz input IF and converts to baseband. This module contains internal gain control and is capable of transmitting up to 7 dBm and receiving a 20 dBm signal. The PXIe-3620 also provides the LO reference signal for the NI mmWave radio heads (mmRH modules). The LO/IF module can optionally accept an external LO signal or can drive the LO signal for other IF modules to synchronize multiple transmit/receiver streams in a MIMO topology. The differential I/Q pairs are accessible through MXC connections on the device front panel.

Figure 8: PXIe-3620 IF module
mmWave heads
The modular mmWave radio heads provide a high quality RF signal for the mmWave Transceiver System and support the following frequency bands.
- 24.25 - 33.4 GHz
- 37 - 43.5 GHz
- 71 - 76 GHz
All of the radio heads support 2 GHz of bandwidth. There is an option of purchasing a transmitter, receiver, or transceiver. For details on the products, please refer to Table 2 below.The mmWave heads contain attenuators and amplifiers for maximum gain control and noise figure. A detailed RF characteristics are listed in Table 3. The radio heads can be connected to a user provided antenna, such as a horn antenna or a phased array antenna.
37 - 43.5 GHz
| 24.25 - 33.4 GHz
| 37 - 43.5 GHz
| 71 - 76 GHz
|
---|
Transmit only mmRH | mmRH 3642
| mmRH 3643
| mmRH 3647
|
Receive only mmRH | mmRH 3652
| mmRH 3653
| mmRH 3657
|
Transceiver mmRH | mmRH 3602
| mmRH 3603
| |
Interface to antenna | 2.92 mm | 2.40 mm | WR-12 waveguide |
Digital Cable Required | Part Number: 785811-01
| Part Number: 785811-01
| Part Number: 784577-01 (Single radio head)
Part Number: 784579-01 (Dual radio heads)
|
Table 2: Product names of the mmWave radio heads and part numbers for required digital cables for each model
| 24.25 - 33.4 GHz | 37 - 43.5 GHz | 71 - 76 GHz |
---|
Receiver | | | |
Instantaneous Bandwidth | 2 GHz | 2 GHz | 2 GHz |
Analog Gain Range | 50 dB | 50 dB | 55 dB |
1 dB Gain Compression1 | -13 dBm | -13 dBm | -12 dBm |
Noise Figure2 | 6 dB | 6 dB | 6 dB |
Transmitter | | | |
Instantaneous Bandwidth | 2 GHz | 2 GHz | 2 GHz |
Analog Gain Range | 55 dB | 55 dB | 55 dB |
Output IP32 | 28 dBm | 28 dBm | 30 dBm |
Table 3: Characteristics of each radio head
1. Near minimum gain, For lower gain settings, 1 dB compression is higher than full scale.
2. At maximum gain
Figure 9: Left: 24.25-33.4 GHz and 37-43.5 GHz radio head
Right:71-76 GHz mmWave radio head