Diverse demands require a forward-looking spectrum allocation.
The 8th Asia-Pacific Spectrum Management Conference was held on April 26th – 27th. The 6 GHz allocation plan is again a hot topic at the conference. In the session “Mapping the potential evolution of the 6GHz band in the APAC region”, a data point given by Mr. Chenda Thong, the Chairman of Telecommunications Regulator of Cambodia (TRC), surprised me. Mr. Thong mentioned that “current data consuming in Cambodia is around 33 GB per user per month.” The data consumption is among the highest in the Asia Pacific region. According to a study report of UN-OHRLLS, Cambodia ranks 12th among LDCs (the Least Developed Countries) in fixed Internet penetration. The fixed broadband subscriptions are just over 1% of total Internet subscriptions in the country, while more than 50% of web traffic was generated by mobile phones. Therefore, mobile broadband networks are the foundation for Cambodian people to be connected to the world.
The case of Cambodia indicates a typical situation in developing countries. Mobile broadband networks play a critical role in overcoming the digital divide. Most of the data traffic is carried by cellular networks rather than fixed broadband. Thus, a sufficient supply of licensed spectrum bands is crucial for developing countries' long-term economic and social developments.
In developed countries, mobile operators are exploring new business models. Strategy Analytics’ OECD Mobile Voice and Data Price Benchmarking service have seen that operators are increasingly differentiating these services both at the 5G level and from 3G/4G/4.5G services and encourage higher spending through headline speeds. Offering speed-based price tiers within unlimited data portfolios and encouraging users to upgrade for the full 5G experience has been a common trend in Finland and used by Vodafone and Telefonica O2 in their unlimited plans in many markets in Europe. As a result, consumers’ demand for an excellent network experience is growing. According to Finland’s regulator Traficom, the proportion of SIMs with a data plan offering (peak) speeds over 300Mbps increased from 2% in H1 2018 to 17% in H2 2021.
Mobile operators could also leverage 5G’s ultra-reliable and low latency (URLLC) capability to develop services with a guaranteed Service Level Agreement (SLA). These services with an excellent experience or a guaranteed SLA will require more spectrum resources than the traditional best-effort services, even if they generate equivalent data traffic.
Therefore, regulators, either in developing countries or in developed countries, should take a forward-looking approach to make sure sufficient spectrum is allocated to cellular networks when they make spectrum allocation plans. The best balance of capacity and coverage for mobile broadband systems can be achieved in the mid-band, such as 3.5 GHz or 4.9 GHz. The 6 GHz band is expected to be the new ‘Golden Band’ (see my previous blog), particularly for 5G-Advanced or 6G in the future.
6 GHz spectrum allocation key for the sustainable development of the global wireless industry
The allocation for the upper 6 GHz band, 6425 – 7125 MHz for the IMT system, will be determined in the coming World Radiocommunication Conference 2023 (WRC-23). As the lower part of this band, i.e., 5925 – 6425 MHz, has been adopted as an unlicensed band in many countries, allocating the upper 6 GHz band for licensed uses will be a forward-looking and balanced approach.
The licensed upper 6 GHz will enable telecom operators to meet the growing data demands, improve user experience and extend network coverage. Mobile broadband networks can connect the unconnected homes or SMBs in developing countries, which will, in turn, stimulate the use of Wi-Fi in homes and offices.
Combining 5G NR, edge computing, and network slicing can also effectively meet the industrial requirements for reliability, latency, and operational flexibility to accelerate the industrial digital transformation. The accelerated transformation will generate more demand for all wireless technologies, either licensed or unlicensed. Thus, allocating the upper 6 GHz band to IMT service will eventually benefit both cellular and non-cellular communities.
Advanced technologies solving coexistence issues
The coexistence with the incumbent services, mainly the fixed service (FS) and the fixed-satellite service (FSS), is an essential issue for the 5G service in the upper 6 GHz band. Long-distance point-to-point/backbone links are typical FS applications on the 6GHz band mainly deployed in rural/remote areas. Considering IMT on the upper 6GHz band is mainly deployed in densely populated areas, nothing is needed to do for most of these FS links, while for the rest very few cases, case-by-case network planning could effectively mitigate the interference suffered from IMT.
For the coexistence with FSS, the main issue is the potential interference from 5G base stations to the FSS uplink. Massive MIMO can play a crucial role in mitigating the interference signals. As the wavelength of the electromagnetic wave at the upper 6 GHz band is just about half of that at 3.5 GHz, the Active Antenna Unit (AAU) for the upper 6 GHz band can integrate four times antenna elements as the AAU for the 3.5 GHz band, while keeping an almost same physical size. The more significant number of antenna elements, the narrower beam can facilitate an advanced upper-sidelobe suppression technique to mitigate the upper side-lobe emissions toward the FSS uplink.
In summary, allocating the upper 6 GHz band to IMT service is a forward-looking and balanced approach to ensure the sustainable growth of the global wireless industry. Advanced technologies and professional network planning can solve the coexistence issues with incumbent services.