5G’s ‘Golden Band’: Exploring the use of 700 MHz spectrum

In the past few years, we have seen 5G deployed around the world in many different forms, using many different bands of spectrum. Each of these bands has specific characteristics, from variable signal propagation to disparate data speeds, making them more or less suitable for certain types of deployment. As a result, based on the spectrum available to them, operators have adopted different strategies to achieve coverage for their customers. 

 

Take the world’s three leading countries in 5G, for example: China, South Korea, and the US. Chinese and South Korean operators have typically focussed their 5G rollouts on mid-band spectrum (primarily 2.6 GHz and 3.5 GHz), which offers a happy medium between speed and propagation. 

 

In contrast, for the US, current rollouts have been focussed on mmWave spectrum (>24 GHz), which offers incredible speeds but limited propagation, and low-band spectrum (600–700 MHz spectrum), which offers lower speeds but much greater coverage. This will soon change, however, following the conclusion of the US’s record C-band (i.e., mid-band, 3.7–4.2 GHz) spectrum auction that raised $81.17 billion.

 

But while the mid-band clearly remains the most popular for 5G, deployments of both mmWave and 700 MHz spectrum are becoming increasingly common.

 

“If we count the number of networks deployed in each band, we can see the C-band is number one, mmWave is number two, and 700 MHz is number three,” explained Guang Yang, providing an overview of the current 5G landscape.

 

However, this balance is gradually shifting. While mid-band spectrum can provide an excellent data experience for customers, its relatively limited range means that a new focus could be needed if 5G services are going to be delivered on a nationwide scale in a cost-effective manner.

 

This is especially true for a country the size of China. Since 2019, China has deployed thousands of base stations around the country – reaching around 960,000 by end of June 2021, according to Guang – but almost all of these are for mid-band spectrum. As a result, despite the scale of China’s rollout, 5G connectivity primarily remain available only in the nation’s major cities.

 

But the 700 MHz spectrum could present a solution. While the speeds offered by this band cannot match that of mid-band 5G, it still offers a large improvement over LTE and its improved signal propagation makes it far more versatile.

 

“We often call this 700 MHz band the ‘Golden Band’ for mobile communications services,” explained Guang. “This band has much better signal propagation and building penetration than higher frequency bands. With this band, operators can provide nationwide coverage in a very cost-effective way.”

 

5G delivered using 700 MHz spectrum will particularly shine in terms of indoor connectivity, a factor which is becoming increasingly vital to 5G success.

 

“For the 5G networks in the C-band, you can only get the connection to 5G when you’re very close to the window,” said Guang. “But for 700 MHz, indoor coverage will be much better. More than 70% of traffic today takes place in an indoor environment, so good indoor coverage is really important to improve user experience.”

 

Operators are quickly coming to realise the value of this spectrum and we are seeing major deployments in many markets around the world. In China, for example, China Mobile and new player China Broadcasting Network have recently issued a joint tender to purchase more than 480,000 700 MHz 5G base stations. Guang suggests that these deployments will be completed by Q1 or Q2 next year. 

 

“This will be the largest 700 MHz 5G network deployment worldwide and it will improve the 5G coverage in China significantly,” said Guang.

 

We should remind ourselves here that 5G is a global ecosystem, where decisions in one major market have knock-on effects in another. In this case, as a result of their new deployment, China Mobile will require smartphone vendors to support 700 MHz band on their devices from October this year, potentially giving the global 5G ecosystem a boost towards wider adoption of this frequency. 

 

Nonetheless, the initial impact will surely be felt most heavily by China Mobile’s rivals in its domestic market.

 

“I think this move gives China Telecom and China Unicom some pressure,” said Guang. “We’re already seeing a reaction. Some weeks ago, these two operators launched a joint tender for 5G base stations in the 2.1 GHz band – they will purchase around 230,000 base stations to improve their coverage.” 

 

This local competition is great news for the likes of Huawei, who were recently announced as the largest winner for the latest China Mobile–China Broadcasting Network tender process, with around 60% market share.

 

“Last year, we saw Huawei dominate the Chinese 5G market with more than 50% share, but for this large project they will have an even higher market share,” explained Guang.

 

Guang notes that this appreciation for low-band 5G spectrum is increasing worldwide, suggesting we will see far more low-band deployments in the coming years as operators battle to become the first to achieve nationwide coverage.

 

“Currently we have over 30 countries that have auctioned or allocated the 600 MHz or 700 MHz bands for 5G. I think in the next one or two years, there will be more than 30 new countries auctioning or allocating the spectrum,” he concluded.