An IDTechEx report cites thermal management as a key challenge facing 5G in meeting its expected goals of delivering low latency and high download rates, while maximising coverage. To illustrate the issue, a recently published report by PCMag comparing 4G and 5G download speeds across various regions in the US (PCMag report) concluded that 5G is not quite ready yet. Verizon showed the fastest download rate at around 2 Gbps but found only 4 % of the network has 5G coverage.
5G utilizes either mmWave spectrum or sub-6GHz with mmWave achieving the fastest download rates but also having the shortest range. Whilst sub-6GHz has a longer range, the tests found in many cases it was actually slower than 4G in the same region. Whilst overall download speeds were improved from 2019, a lot of this is down to improvements in 4G infrastructure. The issue is that mmWave is the more technically challenging technology and as the 5G networks evolve we expect to see a large increase in mmWave installations and hence many opportunities for new materials and technologies. The above tests, however, highlight that whilst there has been a lot of hype relating to 5G, there are still many challenges and a long way to go until reality catches up.
According to the IDTechEx report, one of the main challenges with 5G infrastructure is thermal management. The higher frequencies utilized by 5G antenna, require increased gain to achieve an acceptable range. Additionally, mmWave spectrum has very poor propagation through surfaces such as walls or windows, hence many more individual antenna units are required to give sufficient coverage. The higher frequencies also reduce the spacing between antenna elements, leading to much more densely packed arrays of electronic components, which all have to dissipate heat. With a greater number and density of antenna installations within the network, active thermal management cooling methods such as fans or liquid cooling may not be as viable as they were for the previous infrastructure.