Overview of the LabVIEW Communications Application Frameworks

Publish Date: Mar 19, 2018 | 4 Ratings | 5.00 out of 5 | Print


The insatiable demand for reliable and ubiquitous yet affordable wireless data connections for both people and machines is putting tremendous pressure on the wireless industry. Industry consensus says that the next generation of wireless networks (5G) needs to improve capacity a thousand fold by 2020 without a commensurate increase in cost. To respond to this technological challenge, wireless researchers need to think outside the box and beyond the desktop simulation environment. They need to progress to the real-time prototyping of wireless systems to fully explore the innovations needed.

However, real-time wireless prototyping is an expensive, time-consuming task. Many factors need to be considered including the disparate skill sets required and the lack of a common hardware platform. But the most important challenge is a lack of viable starting points for the existing prevalent wireless standards such as LTE and 802.11 as well as new technologies such as massive multiple input, multiple output (MIMO).

The LTE, 802.11, and MIMO application frameworks provide ready-to-run, easily modifiable real-time physical layer (PHY) and medium access control (MAC) layer reference designs. They are composed of modular baseband PHY and MAC blocks implemented using the LabVIEW Communications System Design Suite (LabVIEW Communications). The frameworks are designed to run on an FPGA and a general-purpose processor, which are tightly integrated with the RF and analog front ends of NI software defined radio (SDR) hardware.

LabVIEW Communications Application Frameworks

Table of Contents

  1. LabVIEW Communications LTE Application Framework
  2. LabVIEW Communications 802.11 Application Framework
  3. LabVIEW Communications MIMO Application Framework
  4. Additional Resources

These application frameworks provide a substantial starting point for researchers to find ways to improve and build prototyping systems. Some example research includes exploring brand-new algorithms and architectures that can support the tremendous increase of the number of terminals, inventing new waveforms by which to modulate and demodulate the signals, or finding new multi-antenna architectures that fully exploit the degrees of freedom in the wireless medium.

The frameworks are designed from the ground up for easy modifiability. This allows wireless researchers to quickly get their real-time prototype up and running based on the LTE and 802.11 standards as well as MIMO technology. They can then primarily focus on the selected aspects of the protocol that they wish to improve, easily modify the designs, and compare their innovations with existing standards.

The PHY and MAC blocks are documented in the product and presented in a graphical block diagram form using LabVIEW Communications. They have clearly defined interfaces, documented system performance benchmarks, and computational resource usage. Additionally, LabVIEW Communications is shipped with a video-streaming application that shows the transfer of real-time data over the air using these standards-compliant wireless links. 

Relevant parameters for the wireless links are easily adjustable from the software front panel generated with LabVIEW Communications. Furthermore, relevant link metrics, including received power spectrum, received constellation, throughput, and block error rates, are also displayed for easy assessment of the link quality. They allow researchers to understand the effects of various parameters on communications performance.

These application frameworks, combined with the ease of development LabVIEW Communications provides and the seamless integration with NI SDR hardware, enable wireless researchers to innovate faster and reduce time to market for their next breakthrough innovations.

1. LabVIEW Communications LTE Application Framework

The latest version of the LabVIEW Communications LTE Application Framework includes:

  • Subset of a 3GPP-LTE release 10 compliant physical layer
    • SISO configuration
    • Closed-loop over-the-air operation with channel state and ACK/ NACK feedback
    • 20 MHz bandwidth
    • Physical Downlink Shared Channel (PDSCH) and Control Channel (PDCCH)
    • Up to 75 Mbps data throughput
    • Normal cyclic prefix mode
    • FDD and TDD configuration 5-frame structure
    • QPSK, 16-QAM, and 64-QAM modulation
    • Variable physical resource block (PRB) allocations
    • LTE-compliant data-channel coding
    • Cell-specific and UE-specific reference signals
    • Primary synchronization signal
    • Sounding reference signal (SRS)
  • Receiver algorithms
    • Automatic gain control
    • Synchronization based on PSS including time and frequency tracking
    • Channel estimation and zero-forcing channel equalization
  • Basic MAC to enable packet-based data transmission and MAC adaptation framework for rate adaptation
  • Hardware support for USRP RIO, NI Linux Real-Time, PXIe-7975/7976 PXI FPGA Modules for FlexRIO, and NI-5791 RF Adapter Module for FlexRIO
  • Multicell and multi-UE support


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2. LabVIEW Communications 802.11 Application Framework

The latest version of the LabVIEW Communications 802.11 Application Framework includes:

  • Subset of an 802.11a/g/ac PHY layer
    • SISO transmission
    • 20 MHz bandwidth legacy (802.11a)
    • 20MHz/ 40MHz VHT modes up to MCS 9 (802.11ac)
    • 80 MHz VHT mode up to MCS 4 (802.11ac)
    • BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM modulation support
    • Convolutional encoding and Viterbi decoding
  • Receiver algorithms
    • Training field-based packet detection
    • Time and frequency synchronization, channel estimation and zero-forcing channel equalization
    • Signal field-based demodulation and decoding
    • Phase compensation
  • Lower MAC layer
    • MAC and PHY interface: PHY-SAP according to 802.11 standard
    • MPDU generation and recognition
    • Multinode addressing, CRC and frame type check, SIFS timing compliant (16µs) ACK generation
    • Clear channel assessment (CCA) information from PHY, processed by MAC
    • CSMA/CA procedure
    • Retransmission
    • RTS, CTS, and NAV support
  • L1/L2 API to interface with upper MAC
  • Hardware support for USRP RIO, NI Linux Real-Time, PXIe-7975/7976 PXI FPGA Modules for FlexRIO, and NI-5791 RF Adapter Module for FlexRIO


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3. LabVIEW Communications MIMO Application Framework

The latest version of the LabVIEW Communications MIMO Application Framework includes:

    • SU-MIMO, MU-MIMO, and Massive MIMO support
    • 50 MHz - 6GHz frequency coverage
    • 20 MHz bandwidth TDD UL and DL
    • Scalable number of base station antennas from 2 up to 128
    • Scalable number of mobile station antennas up to 12 antennas
    • Support for up to 12 spatial streams
    • Fully reconfigurable frame structure based on LTE
    • 128x12 MMSE, ZF, MRC MIMO precoder/equalizer FPGA IP
    • 4-QAM, 16-QAM, 64-QAM, and 256-QAM modulation support
    • Channel reciprocity calibration enabling reciprocity-based precoding 
    • AGC and open-loop power control
    • Over-the-air synchronization
    • Basic MAC functionality supports packet-based user data transmission in DL and UL to enable data-streaming applications such as video transmission

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