The deployment of 5G should be viewed as an evolution that builds on all spectrum assets. Communication service providers need to be able to make best use of the performance characteristics of each band to support their business strategy while maintaining coexistence between all the technologies deployed in the network.
The need for new additional spectrum for the advancing generations of cellular technologies and mobile networks has grown over the years based on growth in mobile data traffic and emergence of new use-cases. And, as communication service providers consider their deployment options for 5G networks, they will need access to significant amounts of spectrum resources to achieve the full performance benefits of the 5G new radio (NR) technology.
However, managing the current and new additional 5G spectrum while also maintaining operations of existing technologies, is a challenge that is increasing with the complexity of combination of spectrum bands (see figure 1). To enable the evolution to a full 5G experience, a complete and comprehensive spectrum strategy is essential – including a plan to handle the migration of technologies. With such a strategy, communication service providers will significantly increase the value of their total spectrum assets by balancing and combining the use of mid-band, high-band and low-band spectrum for optimal coverage, capacity and quality performance.
Spectrum properties and opportunities
Each spectrum band represents unique properties, meaning there are diverse opportunities for a service provider to balance between throughput, coverage, quality and latency, as well as reliability and spectral efficiency. Availability of spectrum will vary globally between countries and regions, both in terms of bands, amounts and timing.
Low-band spectrum is currently being used for 2G, 3G and 4G services for voice, MBB services and Internet of Things (IoT). Newly allocated spectrum for mobile networks include the 600 MHz and 700 MHz bands. These bands are ideal for wide-area and outside-in coverage as well as for deep indoor coverage, typically required for eMBB and voice services.
Mid-band spectrum is currently used for 2G, 3G and 4G services. New spectrum has been widely allocated in the 3.5 GHz band, with more spectrum planned to be made available in the 1.5 GHz (L-band) and 5 GHz (unlicensed) bands. Bandwidths of 50 megahertz to 100 megahertz per network will enable high-capacity and low-latency networks ideal for 5G use cases such as enhanced MBB (eMBB) and Ultra Reliable Low Latency Communications (URLLC), for critical IoT applications. With better wide- area and indoor coverage than high-band spectrum, the mid-band spectrum is an optimal compromise between coverage, quality, throughput, capacity and latency. Combining the mid-band spectrum with low-band spectrum leads to exceptional network improvements in terms of capacity and efficiency.
High-band spectrum clearly provides the anticipated leap in data speed, capacity, quality and low latency promised by 5G. New spectrum bands are typically in the range 24 GHz to 50 GHz, with contiguous bandwidths of more than 100 megahertz per network. The high-band provides a significant opportunity for very high throughput services for eMBB, localized deployments and low latency use cases, e.g. industrial IoT, venues, etc, both for indoor and outdoor deployments. Fixed wireless access (FWA) will also benefit from these higher bands in terms of capacity. For wider-area coverage, combinations with low-band and mid-band are essential.
Planning for what’s ahead
It is important to view the deployment of 5G as an evolution that builds on all spectrum assets. Communication service providers need to be able to make best use of the performance characteristics of each band while maintaining coexistence between all the technologies deployed in the network, to match their business strategy and use-case focus.
Spectrum currently used for 4G can be migrated smoothly to 5G over time, with functions that enable combinations of both bands and technologies. Such functions will be crucial for the successful introduction of 5G (see figure 2).
To allow for a smooth introduction, Ericsson has developed solutions that enable a stepwise introduction of 5G in current network designs that utilize and combine current technologies and spectrum assets. These include dual connectivity between 4G and 5G, spectrum sharing (4G/5G carriers sharing same spectrum) and inter-band carrier aggregation. As an example, Ericsson Spectrum Sharing enables full control to smoothly introduce 5G in an existing 4G network, as well as the possibility to turn on nationwide 5G services within existing bands from day one.
When it comes to mobile spectrum and technology generations, the whole can be greater than the sum of the its parts.