LabVIEW Communications Application Frameworks

Publish Date: May 22, 2017 | 2 Ratings | 5.00 out of 5 | Print

Overview

The insatiable demand for reliable, ubiquitous, yet affordable wireless data connections for both people and machines is putting tremendous pressure on the wireless industry. There is industry consensus that the next-generation of wireless networks need to improve capacity 1000-fold by 2020, without a commensurate increase in cost. To respond to this technological challenge, wireless researchers need to think outside the box, and extend beyond the desktop simulation environment and onto real-time prototyping of wireless systems in order to fully explore the necessary innovations needed.

However, real-time wireless prototyping is an expensive, time-consuming task. There are many factors including the disparate skill sets required, lack of a common hardware platform, and most importantly, because there is a lack of viable starting points so that researchers can build upon the existing prevalent wireless standards (LTE and 802.11).

The LTE and 802.11 Application Frameworks, included with the LabVIEW Communications System Design Suite (Communications), provide ready to run, easily modifiable real-time physical layer (PHY) reference designs based on the LTE and 802.11 wireless standards.  

Table of Contents

  1. LTE Application Framework
  2. 802.11 Application Framework
  3. Additional Resources

These application frameworks provide a substantial starting point for researchers to find ways to improve the LTE and 802.11 standards. Some example research include 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 LTE and 802.11 application frameworks are comprised of modular baseband physical layer blocks implemented using 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 the NI Software Defined Radio (SDR) hardware. 

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

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

Relevant parameters for the wireless link 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 and allow the researcher to comprehend the effects of various parameters on the communications performance.

These application frameworks, combined with the ease-of-development on LabVIEW Communications, and the seamless integration with the NI SDR hardware family, enables wireless researchers to innovate faster and lessen time to market for their next breakthrough innovation.

1. LTE Application Framework

The LTE Application Feature Set version 1.1 includes:

  • Subset of a 3GPP-LTE release 10 compliant physical layer
    • SISO downlink and uplink transmission for closed-loop over-the-air operation with channel state and ACK/ NACK feedback
    • 20 MHz Bandwidth
    • Normal cyclic prefix mode
    • FDD and TDD Config 5 frame structure
    • QPSK, 16-QAM, and 64-QAM modulation
    • Variable physical resource block (PRB) allocations
    • LTE compliant data channel coding
    • Physical Downlink Shared Channel (PDSCH) with up to 75Mbps throughput
    • Cell-specific and UE-specific reference signals
    • Primary synchronization signal
    • Sounding reference signal (SRS)
    • PDCCH for controlling the PDSCH parameters
  • 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
  • HW Support for FlexRIO PXIe-7975/7976R + FAM 5791 and USRP RIO 29X0R /29X2R /29X3R (40 MHz & 120 MHz BW)

 

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2. 802.11 Application Framework

The 802.11 Application Framework Feature Set version 1.1 includes:

  • Subset of an 802.11a/g/ac physical layer
    • SISO transmission
    • 20 MHz bandwidth legacy and 20MHz/ 40MHz VHT modes
    • BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM Modulation
    • 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
    • Multi-node addressing, CRC and frame type check, SIFS timing compliant (16µs) ACK generation
    • Clear channel assessment (CCA) information from PHY, processed by MAC
  • HW Support for FlexRIO PXIe-7975/7976R + FAM 5791 and USRP RIO 29X0R /29X2R /29X3R (40 MHz & 120 MHz BW)

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