5G development efforts accelerate

Initial experiments took place in BT’s large exhibition hall and used 12 streams in a single 20-MHz channel to show the real-time transmission and simultaneous reception of 10 unique video streams, plus two other spatial channels demonstrating the full richness of spatial multiplexing supported by the system.

In addition to the indoor trials, the researchers conducted a series of outdoor experiments with the array at a height of around 20 meters, enabling far-field array characterization and multi-element handset performance measurements; they also carried out experiments to improve the understanding of the massive MIMO radio channel under mobile conditions.
NI reports that to achieve accurate, real-time performance, the researchers took advantage of FPGAs using LabVIEW Communications and the recently announced NI MIMO Application Framework (Figure 2). As lead users, both the Universities of Bristol and Lund worked closely with NI to implement, test, and debug this framework prior to its product release.
The Bristol, Lund, and BT researchers said they now are processing the data sets and aim to publish their findings in leading journals in the near future as well as adding enhancements to the system in preparation for further trials.

Mark Beach, professor of radio systems engineering in Bristol’s Department of Electrical and Electronic Engineering, explained in a press release, “We are delighted to be collaborating  with BT. Massive MIMO is a key technology for 5G, and the research team’s achievements last year with massive MIMO arrays, which are cellular base stations with more than 100 antennas, demonstrate that this technology could deliver ultrafast data rates to high densities of smartphones and tablets.”²

Professor Tim Whitley, managing director, research and innovation at BT, added, “The BT Labs have a long history of pioneering wireless research, and with the acquisition of [British mobile network operator] EE, we’re excited to once again be at the forefront of mobile technology development. Massive MIMO has the potential to significantly boost available data rates in future 5G mobile networks, and we’re pleased to be able to explore that potential with leading academics in the field at the University of Bristol.”

Kimery said NI also collaborated with European researchers on new potential 5G waveforms in the European Union funded project, 5GNOW, including GFDM and UFMC. “In fact, researchers at TU Dresden demonstrated several GFDM prototypes using LabVIEW Communications and the NI USRP running in real time including a 2×2 MIMO system—the first ever MIMO system using these new waveforms to demonstrate a complete communications link,” he said.

In addition, in March NI presented what it called the world’s first public demonstration at 28 GHz of a real-time, over-the-air prototype aligned with the Verizon 5G specification at the IEEE Wireless Communications and Networking Conference in San Francisco. The system uses OFDM with eight component carriers in a 2×2 downlink MU-MIMO configuration with hybrid beamforming and a self-contained subframe, yielding a 5-Gb/s peak throughput, and it is scalable to over 20 Gb/s with eight MIMO streams.

Verizon announced the availability of its 5G Technology Forum specification in 2015. Although the industry is developing products and technologies to conform to the standard, no public over-the-air demonstrations have occurred at 28 GHz until now, NI reports.

“This prototype demonstrates the power of the NI platform,” said Kimery. “Researchers can take advantage of the combination of hardware and software to rapidly prototype new wireless standards and iterate quickly to reduce time to results. They now can prototype and test the Verizon 5G specification and move immediately to 5G New Radio once the standard stabilizes.”

5G trials in China

Keysight recently announced two initiatives with regard to 5G development in China. The company said it has begun working with Huawei on phase II of the China 5G technology trials. Using its UXA N9040B signal analyzer and 89601B VSA signal analysis software, Keysight has conducted the first integration tests with Huawei’s 5G prototype base station. The tests cover numerology, frame structure, and 5G New Radio.

Led by the IMT-2020 (5G) Promotion Group, and fully initiated in January 2016, the China 5G technology R&D trial involves the operators, system equipment manufacturers, chip manufacturers, and testing service providers. The tests are divided into three phases—key technology verification, technical program validation, and system program validation. Phase I tests were successfully completed in 2016.

Phase II started in the second half of 2016 and is focused on the verification and validation of wireless air interface and networking technologies used in the four major 5G scenarios:

• continuous broad coverage,
• hot spot high capacity,
• URLLC, and
• massive connections.

The tests have already started and are scheduled to be completed by the end of 2017.

Keysight also said it is collaborating with ZTE to assist in the test and measurement of critical 5G key technologies, including millimeter wave (mmWave) communications, massive MIMO, and base transceiver station (BTS) beamforming prototypes. Keysight will help ZTE accelerate 5G time to market by providing products including UXA mmWave signal analyzers, AXIe modular ultrabroad bandwidth signal generation and analysis systems, and system-level prototype solutions.

ZTE is a comprehensive telecommunication solution provider that is a participant and contributor of 5G communications. ZTE is one of the first group of companies that completed the China 5G trials phase I. ZTE’s mmWave 5G BTS prototype now is under test in phase II.

In yet another collaborative effort, Keysight has joined the 5G Automotive Association (5GAA). Citing its expertise in 5G design and test, as well as its collaborations with leading 5G research companies and academics, Keysight said it looks forward to contributing in connecting together the next-generation 5G wireless communication and the automotive technologies to innovate connected mobility and road safety.

As an active member in a number of automotive industry associations, wireless standard organizations (including 3GPP), and leading 5G consortia, Keysight said it is playing a strategic role in providing the broadest design and test tools—from legacy 2G, 3G, and 4G to emerging 5G wireless technologies. Keysight currently provides the automotive industry with a comprehensive array of design, simulation, and test solutions for 5G research, including a 5G exploration library of simulation software.

The 5GAA was formed on Sept. 27, 2016, and comprises automakers and network providers that are collaborating to solve issues related to connected mobility and road safety needs through 5G mobile networks. Applications that 5GAA is working on include connected-car autonomous driving, ubiquitous access to services and integration into smart cities, and intelligent transportation.

And finally, in March Leti presented a paper titled “A Comparison of Indoor Channel Properties in V and E Bands” at the 11th European Conference on Antennas and Propagation in Paris. The paper describes wideband channel measurements in the 59- to 65-GHz and 80.5- to 86.5-GHz frequency bands. Measurements were performed by means of mechanical steering of directive antennas at both transmitter and receiver sides, allowing double-directional angular characterization. For each band, researchers compared propagation characteristics such as the path loss and multipath clusters’ properties in the delay and angular domains.

“These results highlight the differences and similarities between the two bands, defining a mmWave channel model, which is crucial for the deployment of future 5G networks,” said Raffaele D’Errico, an author of the paper, in a press release. “These mmWave bands can be used to carry a significant share of the data load in those networks.”

New 5G-related products

In addition to assisting with 5G trials in China, Keysight has recently introduced products related to 5G development, as have Tektronix and MathWorks. The latter, for example, in March announced its Release 2017a. Ken Karnofsky, senior strategist, signal processing applications, MathWorks, said the new release offers several new capabilities that are applicable to 5G:

• a 5G library for channel modeling, link simulation, and development of candidate 5G waveform algorithms;
• hybrid beamforming simulation, including antenna array design and RF/digital partitioning;
• a WINNER II channel model for simulation of MU-MIMO LTE and 5G systems;
• rapid design of low-cost (integrated) printed antennas used in IoT/M2M applications; and
• RF budget analysis, simulation, and verification of homodyne and superheterodyne RF transmitters and receivers.

Karnofsky said that the new release builds on the capabilities of the company’s MATLAB and Simulink that engineers were already using in the design of various 5G technologies, including the following algorithms and architectures:

• digital predistortion and crest-factor reduction algorithms, which require fast simulation of accurate RF models together with compensating DSP algorithms;
• hybrid beamforming architectures for massive MIMO systems, where the number of digital receiver paths can be limited by partitioning beamforming across analog and digital parts of the system; and
• future antenna architectures where the tightly coupled nature of the system requires antenna, RF, and digital ICs to be considered as an integrated system.

A key is Simulink’s support for multidomain simulation—permitting full-system verification of digital, RF, and antenna design in conjunction with MATLAB. 5G technologies can drive up the cost of development and create a strong incentive to get the implementation right the first time, Karnofsky said, adding, “As a result, 5G engineers look to multidomain simulation as an effective method to verify designs and eliminate errors as early as possible.”

PXIe instruments

For its part, Keysight announced 10 new PXIe instruments that enable research in 5G, aerospace and defense, and quantum technologies, according to Sheri DeTomasi, modular program lead.

The instruments include an arbitrary waveform generator (AWG) as well as what DeTomasi called the industry’s first full-featured PXI oscilloscope. The AWG, which incorporates three highly synchronized channels for precise tuning of I/Q waveforms and envelope tracking, and the oscilloscopes provide up to 1 GHz bandwidth to support complex baseband I/Q signal generation and analysis for evaluating emerging 5G and aerospace and defense wideband technologies.

The new PXI offering includes digitizers and AWG and digitizer combinations that allow engineers to build onto the instrument’s core capabilities or insert custom algorithms into the onboard FPGAs. A graphical design environment makes it easy to add the customization required for emerging technologies while providing access to the full performance and speed of the FPGA. The M3xxxA AWGs and digitizers use the FPGA and PXI reference clock to provide real-time sequencing and multichannel/multimodule synchronization to support advanced multichannel applications like multi-user beamforming technologies and quantum computing.

DeTomasi said engineers are facing challenges in applications extending from the IoT, 5G, and the connected car to electronic warfare, radar, and military radios as they contend with higher frequencies, wider bandwidths, multiple channels, and new, denser modulation schemes. With the new PXIe family, she said, Keysight is leveraging its software and measurement IP across platforms to shorten time to market.

For 5G applications, Tektronix supports PHY layer testing of mmWave and wideband wireless links and radios as well as validation of the performance of high-throughput optical backhaul links, according to Chris Loberg, the company’s senior manager for performance instruments marketing. The company’s most recent innovation in those areas is on the optical front, in the form of new optical modules for its DSA8300 sampling oscilloscope (Figure 3).

“For the optical backhaul networks, the need to improve throughput and ensure error-free communications is important for component and system manufacturers supplying faster interconnect technologies,” he said. “For NRZ and PAM4-based optical formats, the DSA8300 sampling scope mainframe with the new 80C17/18 (multimode and single-mode) optical sampling modules provides high-sensitivity, low-noise optical measurement capability suitable for 28-Gbaud ORR-compliant measurement evaluation.”

When installed in DSA8300 sampling oscilloscopes, the new 80C17 and 80C18 optical modules provide mask test sensitivity of -14 dBm that exceeds requirements for 28-Gbaud PAM4 standards while offering what Loberg called the industry’s best noise performance at 3.9 µW with broad wavelength support. The two-channel 80C18 enables optical manufacturing test engineers to double throughput and capacity. If a device fails, Tektronix offers analysis tools to decompose the signal content for both noise and jitter to help engineers understand the underlying problem.

5G at IMS

Looking ahead, 5G is likely to be a hot topic at the International Microwave Symposium, June 5-9 in Honolulu. In March, the IEEE Microwave Theory and Techniques Society (MTT-S) in partnership with the IEEE Communications Society announced their collaboration on a special 5G Summit to be held June 5-6 in conjunction with IMS. The summit will feature industry experts representing both the hardware/systems and networking/services aspects for the upcoming 5G standard.

Flavio Bonomi, founder and CEO of Nebbiolo Technologies, and Professor (Emeritus) Arogyaswami Paulraj of Stanford University will make a keynote presentation. Bonomi will provide an overview of 5G and show the relationship between fog computing and networking as a key enabler of the technology; Arogyaswami will focus on the latest research in massive MIMO.

For an insider’s view of 5G, the Summit includes the 5G Executive Forum, a two-hour session with executive leaders in the field that will be open to all conference attendees—concluding with a networking reception. Speakers include the following:

• Dr. Sanyogita Shamsunder, executive director, 5G Strategy/EcoSystem, Verizon;
• Dr. Vida Ilderem, vice president of Intel Labs and director of wireless communication research;
• Dr. Bami Bastani, senior vice president for the RF business unit at GLOBALFOUNDRIES;
• Dr. Michael Stewart, CEO and a co-founder of Escape Communications;
• Dr. Khurram P. Sheikh, CEO of Kwikbit; and
• Dr. Mark Pierpoint, vice president and general manager of the Internet Infrastructure Solutions Group at Keysight Technologies.

“5G is a leading topic in the industry right now and co-locating a summit with the world’s largest RF and microwave event is a great opportunity. IMS brings thought leaders from industry, academia, and government together, representing all aspects of the 5G spectrum from MTT-S’s focus on hardware and systems to ComSoc’s networking and services focus,” said Doug Zuckerman, consultant at Vencore Labs and member of IMS2017 5G Summit Committee, in a press release.

“IMS is the place to learn and discuss the future of key technologies so it was a natural fit for an event like the 5G Summit,” added Debabani Choudhury of Intel Labs and IMS2017 5G Summit Committee Chair. “Our 5G Summit speaker list is a testament to IMS being the place where thought leadership happens.”

References

1. Nelson, R., “Pivotal year sees standardization proceed,” EE-Evaluation Engineering, April 2017, p. 6.
2. Nelson, R., “NI supports Bristol, Lund 5G field trials at BT nearing 100-b/s/Hz spectrum efficiency,” Rick’s Blog, EE-Evaluation Engineering, March 4, 2017.