The battle for 5G technology routes is essentially a battle for frequency bands. At present, the world uses two different frequency bands to deploy 5G networks, the frequency band between 30-300GHz is called millimeter wave; the other is called Sub-6, which is concentrated in the 3GHz-4GHz frequency band.
Subject to the physical characteristics of radio waves, the short wavelength and narrow beam characteristics of millimeter waves enable signal resolution, transmission security, and transmission speed to be enhanced, but the transmission distance is greatly reduced.
According to Google’s 5G coverage test for the same range and the same number of base stations, the 5G network deployed with millimeter waves can cover 11.6% of the population at a rate of 100Mbps, and 3.9% at a rate of 1Gbps. 6-band 5G network, 100Mbps rate network can cover 57.4% of the population, and 1Gbps rate can cover 21.2% of the population.
It can be seen that the coverage of 5G networks operating under Sub-6 is more than 5 times that of millimeter waves. In addition, the construction of millimeter wave base stations requires about 13 million installations on utility poles, which will cost $400 billion, so as to ensure 72% coverage at 100 Mbps per second in the 28GHz band and about 55 per second at 1Gbps. % coverage. The Sub-6 only needs to install a 5G base station on the original 4G base station, which greatly saves the deployment cost.
From coverage to cost in commercial use, Sub-6 is superior to mmWave in the short term.
But the reason is that the spectrum resources are abundant, the carrier bandwidth can reach 400MHz/800MHz, and the wireless transmission rate can reach more than 10Gbps; the second is the narrow millimeter-wave beam, the good directionality, and the extremely high spatial resolution; the third is the millimeter-wave components Compared with Sub-6GHz equipment, it is easier to miniaturize. Fourth, the subcarrier interval is large, and the single SLOT period (120KHz) is 1/4 of the low frequency Sub-6GHz (30KHz), and the air interface delay is reduced. In private network applications, the advantage of millimeter wave is almost crushing Sub-6.
At present, the vehicle-ground communication private network implemented by millimeter-wave communication in the rail transit industry can achieve a transmission rate of 2.5Gbps under high-speed dynamic, and the transmission delay can reach 0.2ms, which has a very high value of private network promotion.
For private networks, scenarios such as rail transit and public security monitoring can give full play to the technical advantages of millimeter waves to achieve true 5G speed.
Post time: Oct-27-2022