5G? I imagine most of our readers still dream of a decent 4G, but in some parts of the world, the trials of 5G networks are in a very advanced stage. Basically, we have to travel to Japan, where the main mobile operator NTT DoCoMo and the folks at Samsung managed to establish two new speed records. The first was maintaining a stable link of 2.5 gigabits per second on a mobile device, and the second was doing it in a car traveling at 150 kilometers per hour, confirming the feasibility of 5G connections on platforms like the Shinkansen train network.
Previous Tests
In October 2015, we talked about a series of evaluations that NTT DoCoMo carried out with Huawei regarding 5G networks. At that time, the peak speed was 3.6 gigabits per second, while the average settled at 1.34 gigabits per second, a number any of us would accept already. We aren't making any discovery by saying that all Western mobile operators leave much to be desired. They are expensive, slow, and restrictive in every sense. Whether due to political issues or a delay in investments, some countries are still deploying 4G networks, and their penetration levels pale in comparison to the top three of South Korea, Japan, and Hong Kong. Now, NTT DoCoMo is back, this time with the help of Samsung.
The Two New Records
The official statement explains that the latest test achieved two new marks. The first is a stable connection at 2.5 gigabits per second, almost doubling the results that DoCoMo obtained last year. The second is that the connection remained operational on a vehicle moving at 150 kilometers per hour. The chosen venue was the Fuji Speedway circuit, and transmissions were carried out using the 28 GHz band, one of the "candidate frequencies" for commercial 5G networks in Japan.
Technical Challenges
While we understand the value of a faster link, the fact that it was on a high-speed vehicle requires additional technical details. Attenuation issues are already difficult to resolve at such high frequencies, and a moving vehicle doesn't help much. DoCoMo and Samsung managed to compensate for this with very advanced variants of MIMO technology that include beamforming and beamtracking. If we think for a moment about Japan's high-speed trains, such efforts make a lot of sense.
