Development of Pattern/Polarization Beam-Division Multiple Access Method for 5G Mobile Communications Technology
Development of Pattern-Polarization Beam-Division Multiple Access Technology that Can Achieve Beam Gain and MIMO Gain Simultaneously
Previously, much of the research on mobile communication technology was based on the MIMO technology, which uses several antennas at the transmitting and receiving systems to increase capacity. If the distance between antennas is large enough in a non-line-of-sight environment, this technology can be used to create independent paths between transmitting and receiving antennas, increasing capacity by simultaneously transmitting various data. However, the MIMO technology has some limitations. Most notably, the size of the antenna becomes too large if it is used together with the beam forming technique, and creating an independent path in a line-of-sight environment becomes challenging, making it difficult to enhance capacity. In recognition of this, the research team led by professor Cho Dong-Ho embarked on studies to develop a pattern-polarization beamdivision multiple access technology that places multiple antennas with sufficiently different radiation patterns in a narrow space. This configuration achieves beam gain by using multiple beams, and MIMO gain within each beam, at the same time. First, the research team developed pattern-polarization antennas capable of achieving large multipath gains in a line-of-sight environment based on different phases, and then successfully developed a technique of integrating pattern-polarization antennas in a narrow half-wavelength space, ensuring low interference.
A number of pattern-polarization antennas were arrayed at half-wavelength intervals to develop a pattern-polarization array antenna with low interference. Then, multiple beams were formed where each beam had multiple pattern-polarization antenna radiation patterns integrated in it. Using several pattern-polarization antennas in each beam, multi stream MIMO signals were transmitted. In this way, the research team developed a pattern-polarization beam-division multiple access technology that is capable of achieving beam gain and MIMO gain based on pattern-polarization antennas at the same time in a line-of-sight environment, which was obtained by dividing the space into multiple beam areas and using multiple pattern-polarization antennas for each individual beam.
The findings of the study show that with an optimal design, the beam gain and MIMO gain can be maximized simultaneously, because the beam gain and the pattern-polarization gain are not completely independent of each other. To validate the pattern-polarization beam-division multiple access technology, a base station was built by using a commercial EPC, commercial LTE modem, digital beam former, and pattern-polarization array antennas. Then a test bed was implemented by using developed base stations and commercial terminals. As a result, it was found that the 2×2 MIMO gain was achieved in each of the 12 beams. The research team is currently working on improving the completeness of the pattern-polarization beam-division multiple access technology through subsequent optimization studies, such as optimum multi-beam generation, beam compensation in consideration of antenna coupling and RF element degradation, etc. In addition, the research team plans to demonstrate the technology’s innovative improvement in wireless communication capacity by operating a millimeter wave adaptive pattern-polarization beam-division beam-forming system during a technology demonstration at the Pyeong Chang Olympic Winter Games.
The development of this technology is of great significance at the national level as well. This is because this study has laid the foundation to secure a technological lead in the 5G mobile communications age by applying the original and core technologies of the pattern-polarization beam-division multiple access system to the standards for the 5G mobile communications. The selection of this technology as one of the top 100 R&D projects in 2016 by the Ministry of Science, Information and Communications Technology (ICT) and Future Planning reflects the importance of the technology. Going forward, as companies develop commercial systems and provide ultra-high-capacity communication services for the original and core technologies of the pattern-polarization beam-division multiple access system developed in this study, the technology is expected to greatly contribute to the promotion of future mobile communication, manufacturing, and service industries.
Prof. Cho, Dong Ho
2016 Annual Report