Standards for 5G test service technologies are unveiled. Developed by South Korean businesses, such as Samsung Electronics, the big 3 operators, etc., in cooperation with global vendors, the new technologies will allow for application of Time Division Duplex (TDD) method in 28GHz super-high frequency band, and provision of wideband service through interaction with LTE technologies.

The Ministry of Science, ICP and Future Planning (MSIP) held the ‘4th 5G Strategy Committee’ under the presidency of Vice-Minister Choi Jae-yoo for following up the status of 5G development and preparation of 5G test services for Pyeongchang Winter Olympics. 18 experts from the industry, universities, research institutes, and governmental agencies such as mobile operators, equipment vendors, small & medium-size businesses, CEO of 5G forum and others were present.

<Key parameters for 5G mobile communication (source: ITU)>

Standards for 5G test service technologies were introduced for the first time at the committee. For the service, 28GHz, one of the high frequency bands proposed as global standards by Korea, was chosen to be used. More than hundreds of ultra-wide bandwidths are required to be able to support 20Gbps, one of the visions for 5G performance. Because such ultra-wide bandwidths are not just available in low frequency band below 6GHz, Korea previously proposed 6 high frequency bands including 28GHz to be used as standard bands for 5G. And this is why 28GHz became a candidate band for the 5G test service.

High frequency bands have shorter wavelength than low bands. To be able to compensate the poor radio signal performance of high frequency bands, extra supports in terms of software and technologies are required. Korean and global businesses, such as Samsung Electronics, the big 3 operators, Nokia and others, have already teamed up to develop chips and equipment that support high frequency bandwidth. Also Samsung Electronics is known to be developing its own chips for 5G test service

TDD method will also be employed to boost frequency efficiency. TDD is a technology that uses a single band for both sending and receiving data by assigning alternating time slots for sending and receiving operations. It gives excellent efficiency - two times better than Frequency Division Duplex (FDD) method that requires dedicated bands for receiving and sending operations. It also offers great flexibility as the ratio of traffic to be transmitted in UL or DL can be dynamically assigned.

However, the main drawback to LTE-TDD method, which is used for 4th generation LTE, is that it gives poor coverage compared to FDD. This is because, with LTE-TDD, UL signal strength is not as strong as DL signal strength. Its low diffraction ratio makes substantial path loss inevitable when signals pass through obstacles like buildings. For this reason, this drawback has become one of the major focuses in 5G innovation.

With standards for 5G test service finalized, discussions about establishing global standards for 5G are expected to take place soon. Relevant parties in the industry in Korea, like enterprises and research institutes, will be aggressively seeking ways to work with global players to secure standardized patents first. To preoccupy the market through successful test services in 2018 and commercialization in 2020, 5G Strategy Committee will work together in efforts to push forward global standards based on performance of 5G test services, approve experimental stations for 5G test services and establish open-type testbeds where the industry, academy and research institutes can co-work.

“Preparations for 5G test service, such as selection of standards, allocation of frequencies, development of chip sets and devices, and more, are taking place without any setbacks.” said the Vice-Minister Choi Jae-yoo. “To occupy global markets in advance, close cooperation between private and public sectors is essential.”