Wireless Transmission of 8K Uncompressed Video Achieved Over >1km
These days, much of our connectivity in the world of technology is wireless – whether it’s 4G or 5G, Wi-fi in its many forms or Bluetooth. There are some fundamental trade-offs in wireless that tend to be made especially as you increase the data rate of any information that you want to transmit. 8K video, particularly when uncompressed, produces high levels of data, so is often subject to those trade offs.Â
The more data you need to transmit, the higher the frequency of the radio signal that you need to generate to carry that data. So, for example, Wi-fi has developed from its initial 2.4GHz frequency to 5 and then 6GHz. Further up the scale, there is a technology previously known as WiGig but also 60GHz Wi-Fi that can be used for higher data rates, up to 7 Gbps.
However, the downside of higher frequencies is that the range of the signal tends to be much lower and is easily blocked by objects such as walls. Some years ago, when the 60Gbps technology was being developed, TV makers tested the option of using the technology between a controller box and a display to allow wireless (in terms of signal if not power) TV sets. Early experiments were stopped when even viewers walking between the transmitters and receivers were enough to block the picture. These days, reliablity has improved and LG, for example, offers its Zero Connect box, although it supports only up to 4K and with a range of 10 meters.
So, we were slightly surprised to see an article in ‘nature communications’ that described a wireless system using 0.22THz (220GHz) communication to transmit at up to 84Gbps over distances up to 1.26 km. 84Gbps is enough bitrate to transmit uncompressed 8K 60P 10 or 12 bit content in 4:4:4 full quality . The research work was done in Chengdu and Shanghai, China. The full paper can be read here.
The scientists published a full table of comparison with other research of this kind here and we have reproduced an extract below.
| Frequency Band | Architecture | Distance (meter) | Bit Rate (Gbps) |
|---|---|---|---|
| 400 GHz | Photonics-based | 35 | 1 |
| 300 GHz | Photonics-based | 100 | 50 |
| 300 GHz | Photonics-based | 0.02– 0.03 | 48 |
| 220 GHz | Electronics-based | 1030 | 20.8 |
| 340 GHz | Electronics-based | 50 | 3 |
| 140 GHz | Electronics-based | 1500 | 2 |
| 300 GHz | Electronics-based | 10 | 1.68 |
| This work | Electronics-based | 1260 | 84 |
The technology was used practically to support the real-time transmission of the uncompressed 8K UHD video in the 31st International University Sports Federation (FISU) in Chengdu, China.
The 8K video signal for this event was separated into four 4K UltraHD video streams left top (LT), right top (RT), left bottom (LB), and right bottom (RB). The signals were then combined again at the output stage. In the practical test three transmitters were used to send signlas from different parts of the stadium to a receiving station that sent signals to the control room and from there to an Outside Broadcast van. Transmission distances at the event were up to 180m,
The graphic is part of the full image (here) https://www.nature.com/articles/s41467-024-52370-x/figures/4 which includes constellation diagrams and spectrums for the four channels.
The researchers highlighted that splitting the signal into four meant that there was a strong need for strict frame synchronization and ultra-low bit error rate to support the uncompressed 8K video transmission. They reported that the signal delay in the system was under 50 microseconds, ensuring real time operation.
Attention was paid to minimizing the size of the antennas used and the group also paid attention to the need to be able to support operation in rainy or high ambient temperature conditions.
