Korea Demonstrates 8K Transmission Over-The-Air for ATSC3.0 at NAB 22
MIMO, as an acronym, stands simply for Multiple Input and Multiple outputs. It is a digital antenna technology that leverages multiple antennas to transmit and receive several data signals simultaneously between the same two points. It is used in many areas of wireless communication, including, for example, in Wi-Fi since Wi-Fi 4 (AKA IEEE 803.11n).
The Korean research institute ETRI and the Korean company CLEVERLOGIC focused on 4G/5G and IoT, set up this ATSC3.0 digital terrestrial transmission demo for NAB 2022, as shown in the diagram below.
|Physical Layer Configurations||Presentation & Transport Layer Configurations|
|Waveform Parameters||FFT Size: 32K Guard Interval: 111.11 us (768 samples) Pilot Pattern: SP16_2||MIMO Encoding||Stream Combining: On|
IQ Polarization Interleaving: On Phase Hopping: On
|Framing & Interleaving||Frame Length: ~250 ms Time Interleave: CTI depth 1024 Freq. Interleaving: On||Video||Codec: SHVC Res: 7680 x 4320 (60 fps)|
|PLP Parameters||Modulation: 4096-NUC|
Code Rate: 13/15 LDPC (64800) Data Rate: 110 Mbps
|Audio||Audio Codec: MPEG-H Sampling Rate: 48,000 Hz|
The demo was explained to me in the following eight blocks.
- Korean broadcaster KBS provided the 8K source material.
- A KaiMedia encoder is used for the encoding.
- CLEVERLOGIC provided the transmitter.
- AGOS contributed the transmission antenna, which is cross-polarized (can just identify a cross shape under the plastic covering).
- The receiving antenna comes from AGOS, and in the photo below, you can see the cross shape in the design of the rake
- CLEVERLOGIC provides the receiver.
- KaiMedia contributed the decoder
- The display TV is from Samsung
The MIMO demo we saw has a physical pipe maximum throughput of 111,22 Mbps at a 6MHz bandwidth. Today that’s more than enough for an 8K signal, as demonstrated in several NAB booths at around 80 Mbps. We noted that when we can move to a nextgen codec like VVC or AV1, which use half the bandwidth, such a physical link could easily carry two 8K signals.
Sung-Ik Park, a Principal Researcher from ETRI, who gave me the demo, explained that two vertical and horizontal streams were used together. He noted that this had been tried before by NHK and a few others. This demonstration showed the first-ever ATSC3.0 product, yet to be named. Park told me that 8K Field trials have been running in Korea since 2020 with KBS. There are no official dates yet for any commercial broadcasting using this technology that brings 8K to today’s DTT. We’d need a specific broadcast frequency and new receivers to get there. However, R&D is underway to deliver a solution compatible with existing receivers, which would still only be able to receive up to HD (possibly 4K). In contrast, new receivers would be able to get 8K.
Note that the Korea Pavilion also hosted a scalable HEVC demo which we’ll describe in more detail in a dedicated article. The demo showed 8K content that was split into two parts. A 4K OTA signal at 20 Mbps gets recombined with metadata from an OTT stream at 60 Mbps. In the NAB demo, this distribution method only added latency of 2s, although this might be greater in commercial deployment.