The competition among 5G technology paths is fundamentally a competition for frequency spectrum. Currently, two main frequency ranges are used worldwide for 5G network deployment:
Millimeter wave (mmWave), operating in the 30–300 GHz range
Sub-6 GHz, mainly concentrated in the 3–4 GHz frequency band
Due to the physical properties of radio waves, millimeter waves feature short wavelengths and narrow beams, which significantly enhance data resolution, transmission speed, and communication security. However, these same characteristics also result in much shorter transmission distances, limiting large-scale coverage.
According to Google’s 5G coverage testing, under the same geographic area and with the same number of base stations, mmWave-based 5G networks can cover 11.6% of the population at 100 Mbps and 3.9% at 1 Gbps. In contrast, Sub-6 GHz 5G networks can achieve 57.4% population coverage at 100 Mbps and 21.2% at 1 Gbps.
These results show that Sub-6 GHz 5G coverage is more than five times greater than that of mmWave under comparable conditions. In addition, deploying mmWave networks requires the installation of approximately 13 million base stations on utility poles, with estimated costs reaching USD 400 billion, to achieve around 72% population coverage at 100 Mbps and approximately 55% at 1 Gbps in the 28 GHz band.
By comparison, Sub-6 GHz 5G deployment can often reuse existing 4G base station infrastructure, significantly reducing deployment complexity and cost.
From the perspective of commercial deployment, coverage efficiency, and cost control, Sub-6 GHz currently has clear advantages over mmWave in the short term.
However, mmWave technology offers unique technical strengths that are difficult for Sub-6 GHz to match. First, mmWave spectrum resources are abundant, enabling carrier bandwidths of 400 MHz to 800 MHz and wireless data rates exceeding 10 Gbps. Second, mmWave’s narrow beamwidth and strong directionality provide extremely high spatial resolution. Third, mmWave components are easier to miniaturize compared to Sub-6 GHz equipment. Fourth, mmWave uses a larger subcarrier spacing, where a 120 kHz slot duration is only one-quarter of that used in Sub-6 GHz (30 kHz), significantly reducing air interface latency.
In private network applications, these advantages make mmWave performance significantly superior to Sub-6 GHz. For example, millimeter-wave-based vehicle-to-ground private communication networks deployed in the rail transit industry have demonstrated data rates up to 2.5 Gbps under high-speed mobility, with latency as low as 0.2 ms, highlighting strong potential for private network deployment.
For private network scenarios such as rail transportation and public security surveillance, mmWave technology can fully leverage its high-speed and low-latency characteristics to deliver true 5G performance.
