Spectrum for 5G networks continue to be a hot topic all over the world. However, for 5G to flourish, additional and affordable spectrum is needed across access and terrestrial wireless backhaul.
The latter doesn’t get as much attention. But the fact is that terrestrial wireless backhaul – using new and refarmed spectrum bands – is key to the future of 5G as well as 4G. Fibre may be the optimum solution, but it won’t be affordable or even available in all the places where mobile operators want to offer mobile broadband. The new ‘Wireless Backhaul Evolution’ report from ABI Research takes closer look at this topic from all angles.
5G will have significant impact on backhaul networks. For the top 30 markets, traffic is estimated to increase to 6,268 exabytes (1 EB equals 1 billion GB) annually by 2027, with 5G accounting for 83% of total traffic by the end of the period. The growth means that most networks in urban areas will be congested within 3 years without access to new wireless backhaul bands (with channel sizes of up to 2 GHz) such as:
- E-band (70/80 GHz): needed as soon as possible
- W-band (92 GHz to 114 GHz): needed by 2024/2025
- D-band (130 GHz to 175 GHz): also needed by 2024/2025
The cost of wireless backhaul
But making the spectrum available is only the first step, getting the licensing process right is equally important. The highest spectrum prices in some markets were found to be 22X higher than the global median and 59X higher than the lowest priced markets. This places a significant burden on operators in some markets, making it more difficult to quickly roll out faster broadband services with better coverage.
An important part of this equation is fees. High backhaul spectrum fees have a significant impact on the total cost of networks in the 5G era. The report describes what the impact of applying high representative maximum spectrum fees across all the microwave and millimetre wave bands for a network in a developed market is. The result a yearly aggregate network TCO of US$1.68 billion, which is 266 per cent higher than the minimum spectrum fee scenario.
Another unfortunate habit is placing fees on operators that adopt innovative backhaul technologies that increase spectrum efficiency. For example, some countries charged operators double the price of a single radio channel link when the operator employed secondary polarisation technology, which doubles spectrum efficiency.
As part of a success terrestrial wireless backhaul strategy, governments and regulators also need to adapt and in some cases protect existing backhaul bands. Existing bands between 6-42 GHz are still important. They depend on some flexibility to accommodate wider channels.
6 GHz is a key band
One of the hottest bands at the moment is 6 GHz. This is an important band for mobile fixed links – the lowest frequency that is widely used for backhaul and thus one of the most affordable. Where there is less fibre, mobile base stations need more backhaul spectrum and the relationship between existing fixed links and the new access connectivity will need to be managed.
So what should happen next? What should governments and regulators do to ensure that 4G and 5G networks can connect more people and things, offer faster speeds, and better coverage without congestion. To help navigate this topic, the GSMA’s spectrum team has developed five recommendations. They are:
1. New backhaul bands are needed to support evolving network requirements and growing traffic;
2. Current backhaul bands will still play an important role but need support to maintain relevance in the 5G era – especially through wider channel sizes;
3. Regulators need to carefully consider the most effective backhaul licensing terms approaches, terms and conditions;
4. High backhaul spectrum prices present a barrier to mobile network evolution, improved coverage and more spectrum efficient backhaul technologies; and
5. Regulators should, in consultation with the industry, ensure the timely availability of a sufficient amount of affordable backhaul spectrum under reasonable licensing approaches, terms and conditions.