The foundation for indoor millimeter-wave 5G mobile communication services has been laid.
Published2020.12.10 15:5028GHz 5G signal transmitted to indoor distributed antennas
20Gbps service in indoor environments such as airports and train stations
Network technology that provides seamless 5G service even indoors has been developed by domestic researchers.
The Electronics and Telecommunications Research Institute (ETRI) announced on the 10th that it has developed the world's first optical repeater technology capable of receiving millimeter wave (mmWave; 28GHz) based broadband 5G signals from a base station and sending them into a building.
Approximately 80% of the mobile data used in daily life is consumed indoors. By utilizing this technology, it is possible to use services at 20Gbps, the maximum transmission speed of 5G, in indoor environments such as airports, train stations, and large shopping malls. Compared to existing methods, transmission capacity, equipment size, and construction costs have been improved, so it is expected to be widely utilized.
The technologies developed by the research team include 'RoF (Radio over Fiber) optical transmission technology,' which converts 5G wireless signals into optical signals and transmits them without signal distortion over a range of up to 5km, and '5G base station interface technology,' which connects outdoor 5G base stations and indoor distributed antenna systems via OTA (Over The Air).
This is a method in which a 5G base station interface installed on the rooftop of an apartment receives a 5G signal from a nearby base station, converts it into an optical signal at an apartment terminal box equipped with RoF technology, and then transmits it to antennas distributed throughout the indoor areas on each floor.
This technology has a high transmission capacity because it can transmit signals by multiplexing 5G signals into 32 bands. Since it does not require the implementation of complex functions like a base station and only requires the implementation of relatively simple functions, the construction cost is one-fifth of that of installing a separate base station.
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The research team announced that they developed a diary-sized RoF (Road of Flight) receiver and implemented RoF technology by embedding it into the host and antenna units that make up an indoor distributed antenna system. They also developed 5G base station interface technology in the form of a laptop-sized independent module to easily interoperate with the host unit.
The research team plans to develop next-generation communication infrastructure construction technology to provide 6G services beyond 5G in indoor environments in the future.
Meanwhile, this achievement was made possible as part of the Ministry of Science and ICT's 'Development of Indoor Distributed Antenna System (DAS) Technology Based on Analog Intermediate Frequency over Fiber (IFoF) for 5G Mobile Communication.' Currently, the research team has completed a total of five technology transfers to optical module and system companies, including HFR, Lightron, Rontec, and JT.
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