Everything you need to know about Spectrum Refarming

The deployment of 5G promises to help Communication Service Providers (CSPs) with new revenue streams by enabling them to bring new use cases to the end-users. However, they need to go for spectrum refarming to bring down their cost and ensure optimum utilization of the spectrum resources.

What is Spectrum Refarming?

In simple terms, spectrum refarming refers to the repurposing of spectrum bands to more efficient technologies and/or new services. For instance, a service provider may be using 900Mhz to provide 2G services. However, with the ever-growing demand for data services, it might want to free some of this 900MHz spectrum for LTE services. The process by which this is done is known as spectrum refarming.

GSMA defines spectrum refarming as a process governing the repurposing of frequency bands that have historically been allocated for 2G mobile services (using GSM technology) for new generation of mobile technologies, including both third-generation (using UMTS technology) and fourth-generation (using LTE technology).

Why is Spectrum Refarming important?

Spectrum is a scarce and expensive resource, and there is a growing need to ensure its optimum utilization.

Mobile radio communications have evolved over the last three decades. From initially carrying only voice, now the networks use UMTS, HSDPA, and LTE to provide mobile broadband services. Typically, 800-900MHz is allocated to GSM bands while UMTS uses 1900/2100 MHz spectrum, and 700MHz, 1900MHz, 2100MHz, and 2400MHz frequency bands are used for LTE services.

Requirement for additional spectrum for LTE and 5G has led to increased spectrum cost, thus driving the need for spectrum refarming. As of 2016, 49% of 4G deployments globally used reframed 2G/3G spectrum, according to GSMA.

At the same time, the number of 2G users is declining in all geographies, opening up an opportunity to use this spectrum for 4G and 5G. In addition, some service providers have already shut down 2G networks as the subscribers have moved to advanced technologies.

Technology neutrality is crucial to allow Communications Service Providers (CSPs) to use the spectrum as per the evolving technologies and markets. The CSPs in different geographies have different technology roadmaps to meet the changing consumer demand. Technology neutrality empowers the CSPs to upgrade from legacy to 4G or 5G deployments and the services delivered as markets develop.

Why is spectrum refarming critical for CSPs in 5G?

The deployment of 5G is crucial for service providers to address the growing data demand and to leverage the ever-increasing pervasiveness of the digital ecosystem. Combination of ultra-high-speed and low latency of less than one millisecond, 5G will enable several innovative use cases in three key categories of enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra-Reliable Low Latency Communication (uRLLC).

Further, 5G is a more spectrum-efficient technology and allows telcos to connect a greater number of people using the same spectrum. Unlike previous communications standards, 5G requires a combination of spectrum in low, mid, and high-frequency bands to deliver on the promise and vision of 5G use cases. A large amount of mid-band spectrum is required to support the effective operation of 5G mobile networks. Most of this spectrum is currently being used for 2G and 3G, thus driving telcos to explore refarming to free up spectrum for 4G and 5G services.

Most of the frequency bands allocated to 5G are mid and high bands. However, to enable wide-area 5G coverage with required cost economics is a challenge. This demands the use of 5G in lower frequency bands as well. The use of spectrum in low-frequency bands is not always possible since most telcos use it for 4G or LTE services. Spectrum refarming is then crucial to realizing the vision of 5G.

Spectrum refarming is a massive opportunity for the CSPs as it helps them bring down the CAPEX by 15-20% in the medium-term while enabling them to maximize the utilization of the available spectrum resources.

What are the challenges associated with spectrum refarming?

There are several challenges associated with spectrum refarming. To begin with, the CSP needs to ensure that there is no service interruption or service degradation as a result of the spectrum refarming initiative. In addition, some devices don’t work over multiple frequency bands and will need to continue on the legacy network.

Before initiating spectrum refarming, the CSPs need to thoroughly analyze the type of devices on the network and the end-user behavior to decide how much spectrum needs to be allocated for different technologies without impacting the quality of services. The service provider will also need to ensure there is no channel interference. Further, a sufficient contiguous spectrum is required to support the simultaneous operations of two or more technologies in a frequency band.

What is the role of AI in spectrum refarming? 

There are essentially two methods for spectrum refarming: static refarming and dynamic refarming, also known as Dynamic Spectrum Sharing. Static refarming involves dividing the existing spectrum band into two halves to deploy 4G and 5G with depleted bandwidth. Unfortunately, this is not conducive to providing an enriched user experience since the bandwidth is reduced.

Over the last few years, Dynamic Spectrum Sharing (DSS) has been growing in popularity as it allows service providers to use the same spectrum band to provide both 4G and 5G at the same time. A crucial advantage of this is that the service providers don’t need to partition a spectrum band. It allows service providers to use the mix of both the legacy and the new technologies without compromising on the network experience of the users.

Further, with DSS, the telcos can continuously increase the proportion allocated to the new technology (5G) as the demand increases. Another crucial advantage is that it is cost-effective since DSS doesn’t require any new hardware and can be deployed as a software upgrade. This way, this approach helps the telcos accelerate the 5G coverage. DSS also allows service operators to upgrade from 5G non-standalone to standalone deployments easily.

Over the last few years, service providers and regulators have started using Artificial Intelligence (AI) for more efficient spectrum management. From spectrum allocation, planning, sharing, and monitoring for traffic load analysis, AI plays a crucial role in overall spectrum management.

Subex Approach

Subex’s solution uses AI/ML-trained models to perform network analytics and capacity management to identify resource usage. The solution analyses network usage on several parameters, including the types of devices on the network, the user behavior, load levels, and data requirements, among others. It is also able to forecast capacity crunch points along the way.

Unlike the traditional solutions, Subex solutions consider various network dimensions like capability and limitations of devices, spectrum efficiency, and network utilization. It analyses the available spectrum bands in the network and suggests what chunks need to be carved out, along with forecast usage and revenue post-spectrum refarming.

Subex’s AI/ML-based service solution helps CSPs improve spectrum management and ensures fast investment returns.

Learn how Subex’s Capacity Management solution can help CSPs optimize their investments and enhance customer experience 

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