5G is recognized as an important infrastructure for both developed and developing countries. By the end of 2021, 79 nations have either commercialized 5G or are conducting 5G trials. Digging further into what frequency is most used - based on IDTechEx's study - it is sub-6 GHz. This frequency band is used in over half of 5G commercial deployments and trails, with just a tiny percentage using mmWave. So far, only 9 countries have commercialized 5G mmWave.

However, this is not surprising given that, the main restriction of mmWave transmissions is their low propagation range. Telecom companies would not employ the mmWave frequency band for national coverage. Looking at telecom operators' deployment strategies, it can be seen that low-frequency bands (for example, 700 MHz) are used for national coverage, whereas sub-6 GHz bands are utilized for city coverage, and mmWave is used for megacity hotspots.

Spectrum outlook from 2G to 5G.

In the latest 5G research market report, "5G Technology, Market and Forecasts 2022-2032", IDTechEx specifically look into the deployment strategy of 5 key regions: the US, China, Europe, Japan, and South Korea. For each region, IDTechEx focuses on two aspects: government strategy and telecom operator strategy for 5G rollout.

• The US
  Government side: In comparison to other nations, the Federal Communications Commission (FCC) has released mmWave spectrum significantly early. It was not until earlier this year that the FCC has finally released sub-6 GHz frequency band. Ripping and replacing Huawei equipment is still a top priority, with the government funding small-scale operators to do so. Given the lack of dominant US-based 5G telecom equipment suppliers, the FCC has also been supporting Open RAN development.
  
  Telecom Operator side: Each operator holds a different portion of the 5G spectrum. As a result, each strategy to 5G deployment differs. Following the C-band (frequency in the sub-6 GHz range) auction earlier this year, AT&T and Verizon both announced plans to roll out mid-band service this year, with the goal of covering 100 million people by 2022.

• China
  Government side: The Chinese government is pushing hard for 5G national development. The Ministry of Industry and Information Technology of the People's Republic of China (MIIT) issued a 5G application "sailing" action plan (2021-2023) in April 2021, laying out a path for the promotion of 5G applications. Three key performance indicators (KPIs) have been identified: Increase 5G user penetration to more than 40%, raise 5G network access traffic to more than 50%, and push 5G penetration in big enterprises to more than 35%. The MIIT has not yet released the mmWave spectrum, although it is expected to do so soon as the Chinese are preparing to use 2022 Winter Olympics as a test bed for mmWave rollout.
  
  Telecom Operator side: One trend seen in China is that operators are working together to construct shared network infrastructure. By May 2021, China Telecom and China Unicom will build 460,000 5G base stations together.

Important technical development/trend in 5G

Though 5G is commercialized, there are still a lot of technical developments going on. 

• The race for lighter Massive MIMO sub-6 GHz radio
  One crucial part of deploying a large-scale 5G network employing massive MIMO gear is that the radio must be lightweight and have a compact footprint, as these characteristics will help operators save significant money on overall deployment. This is where silicon comes in.

• Small cell deployment
  Small cells are proposed to address the challenge of short signal propagation range caused by high frequency. Creating an ultra-dense network by deploying more small cells plays a key role in 5G as it allows to complement the macro network and therefore boosts data capacity. Furthermore, the deployment of small cells brings 5G to a variety of businesses, facilitating digital transformation. Small cells can be categorized into three types: femtocells, picocells, and microcells, depending on their output power.

5G small cells deployment scenarios and use cases. 

• Open RAN development
  Open RAN is a network alternative to traditional legacy RAN that enables interoperable components (including hardware and software) from different providers to work together seamlessly. It is proposed to eliminate the proprietary nature of the radio access network (RAN) system, diversify the vendor supply chain in the telecom industry, foster more innovation, and reduce the upfront and operational cost of RAN deployment.

• mmWave development
  IDTechEx believes that there are still some years to go before seeing mmWave market take off (see this recent IDTechEx article for a more in-depth discussion). There are still other obstacles to overcome, such as cost, power, packaging, and thermal management concerns. 

Outlook for 2022 and beyond

5G market is just about to take off. By the end of 2032, consumer mobile services are anticipated to generate US$800 billion in revenue, and 5G macro infrastructure markets will expand seven times larger than in 2020, according to IDTechEx. Other key points include:

• For many years to come, sub-6 GHz will be the main frequency for deployment, whereas mmWave will require further technological advancement as well as a killer app to gain market, which will take years 

• The US-China relationship, as well as the development of Open RAN, will have an impact on the 5G system's player dynamics 

• Si is critical to the advancement of 5G since its performance has a substantial impact on connection speed, capacity, power consumption, product size, and weight, and, ultimately, the cost of a 5G system 

• Small cells will play a major role in enabling 5G to replace cable connectivity in the industrial setting 

• The mmWave research and development trend focuses on low-loss materials, power and thermal management, and advanced packaging.