Blog
Spectrum: Where We've Been, Where We're Going?
Sep 23. 2021-
Mohammed Mohiuddin
Director of Strategy, Networks Business, Samsung Electronics America
With each new wireless technology, users and businesses are consuming more and more data. Mobile traffic in 2020 is estimated at 35 exabytes1 (EB) per month and capacity forecast to grow to 171 EB by 2027, a CAGR of 25 percent. The evolution of smartphones which led to increased music downloads and video streaming contributed to this growth, while smart cities, smart factories and autonomous cars will further add to the load in future mobile networks in the coming years. As a result, mobile operators are constantly looking for ways to stay ahead of the trend by using various wireless technologies, including massive MIMO and beamforming, or by tapping new ways to maximize spectrum efficiency.
The communications spectrum has traditionally been controlled primarily by governments, which then allow mobile network operators (MNO) to acquire exclusive rights to a specified band in a particular area. For example, in the United States, suppose the 700MHz band is operated by a telecom company in a specific city, then no one else is allowed to broadcast on that band in that particular area. As we can learn from this example, spectrum is a limited asset, hence costly to acquire or use.
To make the best out of this scarce resource, spectrum sharing has joined the toolbox for many mobile operators looking to expand network capacity. It can be defined as a way to improve spectrum use, allowing multiple mobile operators to share the same band in a specific area. Taking various forms, spectrum sharing is technologically feasible and commercially attractive. Through this blog I would like to go over some of the main forms of spectrum sharing and the future it holds.
Coordinated & Uncoordinated Spectrum Sharing
One example of coordinated spectrum sharing is the Citizens Broadband Radio Service, or CBRS, in the United States. CBRS operates at the 3.5GHz band and is an example of priority sharing. There are three tiers of users for CBRS: incumbents, licensed (referred to as Personal Access Licenses, or PALs) and unlicensed. When using sensor networks (Environmental Sensing Capability, or ESC) and access databases (Spectrum Access System, or SAS), unlicensed users are allowed access if no incumbent or PAL holder is using them, and PALs can use them if no incumbents are using them. These incumbents are primarily the US Navy in coastal areas and Wireless Internet Service Providers (WISPs) in known locations.
For CBRS, Samsung offers an extensive lineup of solutions, including outdoor small cell, 4T4R radio and 64T64R Massive MIMO radio. Samsung’s 4T4R radio is a compact radio solution that supports split-mode to operate both 4G and 5G simultaneously. 64T64R Massive MIMO radio also supports both 4G and 5G, while leveraging advanced beamforming technology.
Currently, Samsung’s CBRS solutions--awarded the OnGo® Certification from the OnGo Alliance--are commercially available, and have been supporting various local service providers with their mobile services in the U.S.
Uncoordinated spectrum sharing means anyone can use it at any time. Wi-Fi is the best example, with the 2.4 and 5GHz bands open to any device that can access it. Some bands that are used for uncoordinated spectrum sharing must co-exist with other devices. For example, Bluetooth devices run in the same 2.4GHz band as Wi-Fi, as do some baby monitors.
In addition to these spectrum sharing forms, there is a new, efficient spectrum technology that enables two different technologies to share the same spectrum simultaneously.
Dynamic Spectrum Sharing for 4G & 5G
The year 2020 saw the emergence of Dynamic Spectrum Sharing (DSS) for 5G. This has allowed both 4G and 5G to dynamically share the same spectrum, reusing existing 4G radios (e.g., antennas). With DSS, mobile operators can swiftly expand 5G coverage while eliminating the need for new spectrum allocation for 5G.
DSS dynamically assigns time-frequency resources between 4G and 5G according to their respective traffic demands to accommodate both users, while optimizing resource utilization. In the current early stages of 5G, DSS is advantageous in that it only allocates the required amount of resources for 5G users, and retains the remaining resources for 4G users. As the demand for 5G grows over time, DSS can allocate more resources to 5G services.
DSS also enables both 4G and 5G to be simultaneously deployed and co-exist in a single carrier. By accommodating both 4G and 5G users on the same spectrum with dynamic resource allocation, DSS solution can effectively maximize operational efficiency and offer a smooth transition from 4G to 5G for operators.
Samsung’s DSS solution can be used on both traditional hardware-bound and virtualized radio networks, enabling the maximum flexibility for customers. This DSS technology has been commercially deployed in the U.S.
The Future of Spectrum Sharing
Spectrum sharing makes for more efficient use of a scarce resource, and the likelihood is that we will see more of it as the world's demand for wireless services continues to grow. One estimate indicates that global investments in shared and unlicensed spectrum will grow from $1.3 billion in 2021 to nearly $4 billion in 2024, a CAGR of 44 percent2.
In the U.S., additional sharing spectrum is being considered for the 6GHz band, and the expansion of CBRS is under research. Other countries have or are setting up systems for spectrum sharing, such as France’s licenses for industrial 4G and 5G networks and Germany’s mid-band licenses for private 5G networks.