The 5G test system must closely integrate pre-research results with practice at all stages, providing researchers and developers with flexible, efficient and reliable test platforms and test data to accelerate the commercialization of 5G products. In this article, we introduce the testing requirements and challenges running through different processes in the 5G industry. Combined with various test scenarios, the test industry’s current R&D status is summarized, technical challenges faced by instrument researchers and developers are highlighted and the potential development of 5G test is forecast.
The information and communications industry is facing great change due to the rapid development of applications, leading to an explosive growth in data traffic. Traditional transmission technologies and architectures for wireless communications are challenged by a variety of smart devices and different connectivity requirements.1-2 The fifth generation mobile communications system (5G) imposes diverse scenarios and extreme performance requirements. Its main operational scenarios include seamless wide area coverage, high capacity hotspots, low power massive connections and low latency with high-reliability.3-4
The 5G technology roadmap contains two parts: a new air interface and a 4G evolution air interface.5 In the 5G air interface technical framework, the key technology areas include massive MIMO, ultra-dense network (UDN), new multiple access and full spectrum access. As one of the most important enabling technologies for seamless wide area coverage, massive MIMO efficiently utilizes spatial dimension resources to dramatically increase system spectral efficiency and enhance the user experience. UDN significantly reduces cell interference through inter-microcell collaboration and expands network capacity in local hot spots. Novel multiple access technologies increase equipment connectivity and reduce signaling overhead, as well as user equipment (UE) power consumption through grant-free mechanisms. Full spectrum access, which supports a hybrid network integrating low and high frequency bands, can simultaneously meet the requirements of high data rates and large capacity.
Since 2013, the U.S., European Union, Japan, South Korea and other countries or regions have launched 5G R&D programs. Since 2014, the Chinese government has supported domestic 5G technology research via the National 863 plan, as well as major science and technology projects. These national or regional initiatives strive to establish favorable positions in future 5G technology and business competitions.6 To establish standards, 3GPP launched 5G research projects in early 2016 and plans to complete the first version of the 5G standard (3GPP Release 15) in 2018. The IMT-2020 group, which consolidates the efforts of industry-university research, was established to promote 5G research and international cooperation. It has released a series of white papers, including 5G Vision and Requirements,3 5G Concept,4 5G Wireless Technology Architecture5 and 5G Network Technology Architecture.7 In January 2016, the IMT-2020 Promotion Group launched 5G R&D experiments to evaluate key technology candidates and facilitate the formulation of technical standards. It plans to complete R&D trials of technologies and products in 2018 and 2020, respectively.
Test technology development has accompanied the development of enabling technologies for each generation of mobile communications, leading to collaborative development. All kinds of test instruments and systems support the multiple needs of the wireless communications industry, from research to verification and production. 5G test and measurement technologies are expected to appear before network and UE products, guiding product design and standard formulation. At present, the first and second phases of developing 5G wireless test specifications have been completed under the organization of the IMT-2020 Promotion Group.