As the demand for connectivity grows, telecommunications providers face significant challenges managing rapid growth and cost of their network infrastructure. Shared spectrum solutions offer a promising answer, using innovative technology to maximise spectrum availability, efficiency, and affordability.
This article explores shared spectrum solutions and how they are revolutionising telecommunications services by improving the immediacy and availability of bandwidth on high growth routes.
UNDERSTANDING SHARED SPECTRUM SOLUTIONS
Shared spectrum solutions are based on technologies designed to enable the secure use and sharing of fibre pairs within the same subsea cable by multiple telecommunications providers.
Unlike traditional fixed capacity models, often dependent upon, and limited by, supplier forecasting and capital investment cycles, spectrum sharing makes spectrum resources immediately available on a fibre pair, thus allowing multiple telecommunications providers to simultaneously utilise the submarine cable infrastructure, independently managing their own capacity growth and investment.
This approach can be segmented into:
Spectrum Sharing Models: Includes co-ownership, Indefeasible Right of Use (IRU) agreements, or consortiums that share spectrum or a fibre pair.
Technology Implementation: Optical spectrum allocation allows the telecommunications provider to choose their own Submarine Line Terminal Equipment (SLTE), decide their own capacity ramp up, and reserve spectrum for growth on key routes.
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This approach can be segmented into:
Spectrum Sharing Models: Includes co-ownership, Indefeasible Right of Use (IRU) agreements, or consortiums that share spectrum or a fibre pair.
Technology Implementation: Optical spectrum allocation allows the telecommunications provider to choose their own Submarine Line Terminal Equipment (SLTE), decide their own capacity ramp up, and reserve spectrum for growth on key routes.
CHALLENGES OF SPECTRUM SHARING SOLUTIONS
While shared spectrum solutions bring significant benefits, they are not without challenges. The complexity of shared infrastructure introduces various technical, operational, and strategic difficulties:
1) Technical Complexity
Managing spectrum sharing involves sophisticated technology that can handle different operators with distinct needs and specifications. Ensuring that shared optical spectrum remains interference-free while maintaining service quality demands.
2) Interoperability Issues
Operators often have proprietary systems that may not seamlessly integrate with ITU Standards based shared spectrum infrastructure. The coordination between different technologies and systems can create unintended bottlenecks, optical power level variances and limit the full potential of shared spectrum solutions.
The current move towards higher baud rate WDM channels, with spectral widths of 150-200 GHz, also needs to be considered.
3) Security Concerns
Sharing infrastructure raises concerns about data privacy, security, network integrity and performance. Unauthorised access, changes or data breaches can potentially affect multiple stakeholders, making cybersecurity protocols, spectrum management and allocation controls essential yet challenging to coordinate across different parties.
TAM-1 ADVANTAGE, ENHANCING BANDWIDTH UTILISATION
The demand for high-speed, reliable, and scalable data transmission across the Americas has never been more critical.
Trans Americas Fiber System (TAFS) is revolutionising connectivity with its TAM-1 subsea cable system, state-of-the-art infrastructure designed to address the exponential growth in data traffic.
In this section I review the specific elements of the TAM-1 design that enables spectrum sharing solutions for our customers.
CREATING ADVANCED SPECTRUM CONNECTIVITY SOLUTIONS
The TAM-1 system spans over 7,200km subsea, connecting Florida with Central America and the Caribbean. The network is designed to provide low-latency, high-reliability connectivity, which is essential for modern digital ecosystems. It consists of a north and a south system, consisting of 12 fibre pairs on the north system and 24 fibre pairs on the south system, creating a design capacity of 648Tbps, representing a massive step change compared to the legacy systems currently operating in the region.
The primary spectrum related feature of TAM-1 is the Spectrum Sharing Gateway (SSG), which is one variant of Xtera’s Open Cable Interface (OCI) equipment and is housed in the cable landing stations. The SSG allows a number of WDM terminals or SLTEs to connect to a single fibre pair, facilitating multiple customers to operate spectrum simultaneously on the same fibre pair.
Each terminal is assigned a unique part of the available bandwidth, with the SSG ensuring that the terminals are isolated from each other in a way that safeguards against issues on one terminal affecting another.
This security is ensured by wavelength filtering to control access to the shared spectrum and monitoring the input signals so that dummy loading can be inserted in the event of missing signals; this might occur due to the failure or disconnection of a terminal. Up to eight terminals can be supported and the assignment of spectrum is flexible down to 6.25 GHz. This fine granularity, and transparency to any data format, means that the system offers a high degree of flexibility with regards to both current and future traffic types.
OADM BU capability is the second feature of TAM-1 which facilitates flexibility of spectrum allocation on a fibre pair. Xtera’s Switched Band OADM (SB-OADM) unit is a subsea module that can be installed in a branch cable, sufficiently far from the Branching Unit such that it can be installed or repaired without disturbing the Branching Unit.
It performs a similar function to a subsea ROADM based on Wavelength-Selective Switches (WSSs) but is of simpler construction, requires less maintenance at a lower cost. It achieves this by switching bands of wavelengths rather than access down to individual wavelengths. The bands are chosen prior to manufacture and are fixed, but the OADM unit can be reconfigured to vary which bands are accessed at a branch at any time – giving our customers increased flexibility of spectrum availability on their traffic paths.
The switches latch, thus preserving the Add/Drop reconfiguration even if the system is depowered. Due to the relative simplicity of the module, it requires only a very simple control system and is easy for the TAM-1 Network Operations Center (NOC) to manage.
By enabling these two discrete types of spectrum management, TAM-1 will be able to offer flexibility and efficiency to operators, allowing them to scale their networks in response to fluctuating demand over time.
BENEFITS ON TAM-1, DYNAMIC SPECTRUM NETWORK SOLUTIONS
Implementing shared spectrum solutions in submarine cable systems provides several advantages that can significantly improve connectivity, and our Dynamic Spectrum Network Solution delivers various benefits:
1) Enhanced Capacity Utilisation
One of the primary advantages of spectrum sharing is its ability to enhance bandwidth utilisation. By allowing multiple operators to use the same subsea cable infrastructure, bandwidth allocation can be tailored to meet operators’ needs without idle resources.
2) Cost Efficiency
Sharing spectrum solutions reduces the investment costs of individual operators. Instead of constructing separate, dedicated cable systems, or acquiring independent fibre pairs, operators can share the cost of infrastructure, making business models more flexible and reliable, reacting swiftly to bandwidth projections over time.
3) Rapid Deployment
By utilising existing submarine cable systems with spectrum-sharing capabilities, network expansions and service rollouts can be achieved faster than deploying entirely new cables. This will accelerate connectivity in underserved regions.
CLOSING THOUGHTS
As the demand for global data transfer continues to surge, the TAM-1 cable system, with its advanced Dynamic Spectrum Network Solution capabilities, is poised to meet the growing connectivity demands across the Americas in a way that offers customers a new type of flexibility for the region.
With continued advancements in technology and cooperative frameworks, these solutions can play a pivotal role in meeting the growing connectivity needs of telecommunication providers, ISPs, hyperscalers, content providers, making global communication more efficient and resilient.
Shared spectrum solutions represent a transformative approach to maximising the efficiency and reach of submarine cable systems. By enabling flexible, multi-operator use of existing infrastructure, allows significant advantages in terms of cost savings, improved capacity, and resource management.
ABOUT THE AUTHOR
With more than 30 years of experience in the information technology (IT) and telecommunications market, Jaime Goldenberg is a co-founder of the private investment group RSL Telecom.
In 2001, the group established itself as a member of the Maya-1 Consortium and as an international provider of submarine cable connectivity services.
Jaime has a successful career as a business developer and as a sales, marketing, and operations manager. In recent years, he was responsible for product development and commercial strategy. He was also in charge of leading the commercial strategy for the Channel Program in LATAM for Ufinet.
Jaime led the Maya-1 Consortium as chairman of the Upgrade and Finance and Administration Committees, managing negotiations and overseeing system expansion implementations.
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