5G millimeter wave is just the right time, and the millimeter wave communication technology innovation seminar was successfully held

On July 17, 2019, the "2019 IMT-2020(5G) Summit" was held in Beijing under the guidance of the Ministry of Industry and Information Technology and hosted by the IMT-2020(5G) Promotion Group and the China Communications Standards Association. The IMT-2020(5G) Promotion Group introduced in detail the latest work progress of the IMT-2020(5G) Promotion Group, which mentioned that the 5G millimeter wave technology research and development test should be promoted in stages.

At present, the definition of 3GPP R15 millimeter wave frequency band has been completed. As my country's 5G industry enters a new milestone, millimeter wave technology is bound to usher in a wave of enthusiasm. On July 23, 2019, the TD Industry Alliance and Keysight Technologies jointly held the "5G Millimeter Wave Communication Technology Innovation Seminar" at the Beijing Taifu Hotel. The theme of the seminar was "Exploring the Limits of Millimeter Wave Technology and Promoting Hot Technology Innovation". Nearly 300 senior experts and scholars, communication operator experts, and representatives of major equipment providers conducted in-depth discussions on topics such as "millimeter wave base stations and networking strategies", "millimeter wave antenna design, process and testing", and "millimeter wave devices, modules, terminals and their testing".

Minutes of seminar speeches

Yang Hua, Secretary General of the TD Industry Alliance, said that the current low-frequency band channels are already very crowded, and the maximum bandwidth of each operator is currently limited to the 100-200M spectrum range, which is not conducive to the performance of 5G. Only by upgrading to the high-frequency millimeter wave stage can user bandwidth be increased by more than ten times. At this time, millimeter waves will naturally come to the fore.

Yang Hua pointed out that the current domestic industrial status quo is that the industrial chain in the medium and low frequency bands is relatively mature, but the industrial chain in the high-frequency millimeter wave band is not perfect, especially the field of millimeter wave devices is weak, which requires 5G network planning to consider both industrial reality and network layout rules.

At present, millimeter wave technology still has the characteristics of large loss, diffraction difficulty, poor penetration, complex coverage scheme, and power consumption and power amplifier efficiency ratio still have room for improvement. At the same time, Yang Hua also said that the current millimeter wave test system needs to be strengthened, including test index design and parameter consistency, which require the industry's efforts.

"5G is recognized worldwide as the beginning of the fourth industrial revolution. Faced with exhausted spectrum resources, millimeter wave is an inevitable choice to enter the historical stage, and it will shoulder increasingly important responsibilities in the future 5G and 6G markets. Although countries have different routes and differences in millimeter wave technology, millimeter wave is ultimately the main battlefield of the future communications market, and making up for the shortcomings of the millimeter wave industry is also the only way for my country." Yang Hua said.

To this end, Yang Hua put forward three suggestions: the government should clarify the 5G millimeter wave spectrum planning as soon as possible; increase industrial chain cooperation, through the system with the whole machine, the whole machine with components, and the special with the general; third, further strengthen international cooperation and strengthen research and development in the testing field.

Zheng Jifeng, General Manager of Keysight Technologies Greater China, delivered a speech and made a report on 5G commercial millimeter wave communication test and measurement technology. The report explains the requirements and challenges of 5G millimeter wave communication test and measurement: channel measurement and modeling, generation and analysis of high-quality broadband millimeter wave modulation signals, MIMO and beamforming, OTA and consistency testing. At present, Keysight's test solutions can fully cover the Sub-6GHz to millimeter wave frequency bands, and can support solutions for different demand parties of network equipment, chips and terminals.

Associate Professor Yu Chao from Southeast University introduced the current progress of the Southeast University Millimeter Wave State Key Laboratory in 5G millimeter wave communication RF technology. Yu Chao said that millimeter wave massive MIMO technology is one of the key enabling technologies for 5G and future 6G. The current beamforming system architecture includes different solutions such as passive multi-beam arrays, all-digital multi-beam arrays, and hybrid multi-beam arrays. The specific solution needs to comprehensively consider the baseband processing performance, overall system power consumption, design complexity and cost, etc. At the same time, Yu Chao said that the current millimeter wave system needs to be strengthened in terms of RF algorithms and fully integrated with the RF system. In order to support higher rates and utilize higher spectrum resources, the RF linearization algorithm can improve the linearity of the system to support higher-order modulation methods; at the same time, the RF algorithm can also be used to improve the efficiency of the power amplifier and reduce the overall power consumption of the system.

Zhang Xiang, chief engineer of the Wireless and Mobile Research Department of the Institute of Technology and Standards of the China Academy of Information and Communications Technology, said that in the current millimeter wave testing, RF and performance index testing is very difficult. At present, there are four test methods for base station RF OTA testing, including far field, compact field, near field and dynamic shaping compact field, and there is no mature solution for performance testing of base stations and terminals under fading channels. The path loss in the millimeter wave band is large, and technologies such as hybrid beamforming and beam tracking are complex. Therefore, it is urgent to develop performance test solutions suitable for millimeter wave base stations and terminals, while reducing testing costs and improving testing efficiency. At present, the China Academy of Information and Communications Technology already has the RF testing capabilities of millimeter wave base stations and terminals, providing a high-performance compact field with a quiet zone of 50cm and a frequency band covering 4GHz-110GHz. It has high capabilities, high dynamic range, high precision and high efficiency, and can test and verify the in-band and out-of-band indicators of millimeter wave base stations, terminals and chips. For millimeter wave base station and terminal performance testing, due to factors such as the limited uplink demodulation capability of the integrated tester, the lack of hybrid beamforming capability, and high power amplifier gain requirements, the China Academy of Information and Communications Technology is actively working with industry partners to research and explore and build an end-to-end performance testing system.

Regarding the millimeter wave base station system, Datang Mobile's Duan Tao said that both all-digital and all-analog beamforming have various shortcomings, so it is necessary to combine digital domain and analog domain waveform shaping technology to make hybrid domain products, reduce the number of RF links, and reduce the complexity of hardware implementation. 5G millimeter wave base stations have brought new demands for high-frequency band RF devices. The current mainstream millimeter wave base station chip solutions include millimeter wave front end + millimeter wave up and down conversion + millimeter wave local oscillator. The millimeter wave front end chip integrates PA, LNA, switch amplitude modulator, etc., and is divided into CMOS/SiGe and GaAS/GaN solutions according to different power. Duan Tao introduced that Datang Mobile is currently taking the lead in organizing the 5G medium and high frequency device innovation center, through the development of the entire communication industry chain, driving the development of key devices and chips with market demand and system design; strengthening the cooperation of upstream and downstream industry chains, jointly meeting the needs of the rapid development of the information and communication industry, and forming a sustainable innovation technology achievement system; at the same time, it advances the technology, standards and industry layout for the evolution of 5G and next-generation communication technologies.

Wang Jianli, 5G high-frequency product manager and chief architect of ZTE, introduced ZTE's roadmap for 5G millimeter wave technology. The current challenges of millimeter wave applications include large propagation loss, requiring high-power TX; poor diffraction and diffraction capabilities, which easily form coverage holes; large millimeter wave bandwidth but limited system processing capabilities, etc. In order to deal with these problems, it is necessary to introduce antenna management arrays, high-frequency beam management, a new wireless frame structure, and high-frequency networking technologies. ZTE started early on the 5G millimeter wave road, and began preliminary research and development work in 2015. At MWC in 2017, it released a number of high and low frequency products covering 3.5G/4.5G/28G/60G, and demonstrated the rate of high-frequency products on site, with a peak rate of 50Gbps. For high-frequency OTA testing, ZTE proposed the ROSE solution, Rayleigh resolution sampling and normalized wave vector space sampling, which were included in the 3GPP standard.

Yang Bo, director of Comba Group Research Institute, said that millimeter wave had been used in consumer electronics and communications before 5G, but it was not that complicated because it was not networked. In the future, 5G millimeter wave construction will face coverage problems and will require the assistance of coverage enhancement equipment, which includes three types: Relay, Passive Repeater and Active Repeater. Comba Group will also continue to innovate in microwave/millimeter wave products and equipment to help 5G millimeter wave construction.

Kong Hongwei, China manager of Keysight Technologies Lab, introduced the reference cases of compact field testing currently conducted by Keysight Technologies, Tsinghua University and CAICT. Among the various types of test methods that have been agreed upon by the industry, such as direct far field method, indirect far field method, near field method, etc., Keysight Technologies has launched a variety of OTA test solutions that meet 3GPP standards, and Chinese researchers at Keysight Technologies Lab have also launched innovative test methods in the mid-field and other directions, achieving good consistency results.

Fan Yonghui, director of the Guangdong 5G Medium and High Frequency Device Innovation Center, introduced the basic situation of the current innovation center. Fan Yonghui said that at present, more than 90% of the power amplifiers and filters in the domestic RF front-end market are occupied by international companies, which has formed a bottleneck restricting the development of my country's 5G industry. The innovation center mainly focuses on three major research and development directions, including: new semiconductor materials and common key technologies and industrialization of processes; key technologies for the industrialization of core devices such as medium and high-end power amplifiers, filters, and array antennas for base stations; and key technologies for RF front-end and silicon-based millimeter-wave integrated chip design. At present, the center's evolution route is divided into three steps, and it will eventually achieve internationally leading various communication RF front-end devices. Fan Yonghui said that the innovation center is currently building an integrated public service platform from material/device research and development-testing-packaging-pilot, and has carried out a number of research and development work around high-frequency millimeter-wave devices, including RF front-end power amplifiers and filters.

Keysight Technologies microwave technical support expert Yang Haichuan introduced Keysight Technologies' millimeter-wave MIMO signal generation and analysis measurement technology solutions. Starting from the basic principle of broadband millimeter-wave signal generation, Dr. Yang systematically introduced Keysight Technologies' latest dual-channel coherent millimeter-wave broadband vector modulation signal sources M9384B and M9383B that support 2GHz bandwidth, as well as millimeter-wave signal generation and analysis solutions that support the generation and analysis of 2GHz bandwidth per channel and up to four channels of phase coherence. Dr. Yang also shared the test results of the 5G NR real demonstration of multi-channel broadband coherent signal generation and analysis. The demonstration works at 29GHz FR2, 400MHz bandwidth per channel, 4*4 MIMO, and EVM is less than 2%. In addition, in the component-level solution, for millimeter-wave applications, Keysight Technologies also provides a network analyzer that supports 110GHz.

Summarize:

Compared with previous generations of mobile communication systems, 5G needs to meet more diverse scenarios and extreme performance challenges. The extreme scarcity of spectrum resources has put forward an urgent need for the coordinated development of high and low frequency bands in the 5G era. The millimeter wave band (above 6 GHz) is an important supplementary band. It provides "endless" frequency resources for mobile users and mobile operators.

Millimeter waves bring large bandwidth and high-speed characteristics, so they have the characteristics of high bandwidth, high speed, high precision, and high resolution in the fields of communication, radar, imaging, and detection. They have broad application prospects in high-speed wireless communications, self-driving cars, non-destructive detection, robot vision, aerospace, etc.