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Network Slicing to Enable Scalability and Flexibility in 5G Mobile Networks
P. Rost, C. Mannweiler, D. S. Michalopoulos, C. Sartori, V. Sciancalepore, N. Sastry, O. Holland, S. Tayade, B. Han, D. Bega, D. Aziz, H. Bakker
TL;DR
5G networks need to support diverse technical and service requirements without sacrificing flexibility or scalability. The paper analyzes network slicing architectures, their RAN and core-network realization, and associated design challenges, while also examining applications and revenue potential. It concludes that slicing has strong potential for addressing diverse future-5G requirements, although the technology remains at an early development stage.
Problem
Future 5G services impose diverse throughput, latency, reliability, availability, energy-efficiency, and cost-efficiency requirements that challenge uniform network designs.
Method
The paper analyzes dedicated and shared slice architectures, RAN and core-network realization options, flexible RAN technologies, and operator-oriented applications and revenue potential.
Results
Network slicing shows strong potential to address diverse future-5G requirements through flexible resource mapping, multi-connectivity, and coexistence of dedicated and shared slices.
Takeaways & Limitations
Network slicing can support latency, reliability, security, resource flexibility, and localized operation for applications such as smart factories and the Tactile Internet.
Abstract
from arXiv · showhide
We argue for network slicing as an efficient solution that addresses the diverse requirements of 5G mobile networks, thus providing the necessary flexibility and scalability associated with future network implementations. We elaborate on the challenges that emerge when we design 5G networks based on network slicing. We focus on the architectural aspects associated with the coexistence of dedicated as well as shared slices in the network. In particular, we analyze the realization options of a flexible radio access network with focus on network slicing and their impact on the design of 5G mobile networks. In addition to the technical study, this paper provides an investigation of the revenue potential of network slicing, where the applications that originate from such concept and the profit capabilities from the network operator's perspective are put forward.
I. INTRODUCTION
5G networks must accommodate diverse technical, service, and operational requirements without deploying separate solutions for every use case. Network slicing offers flexible, scalable logical networks, but introduces challenges in resource sharing, security, mobility, and slice admission.
- Motivation: Future mobile networks must support varied throughput, latency, reliability, availability, energy-efficiency, and cost-efficiency requirements.These requirements arise from diverse services and applications such as Industry 4.0, vehicular communication, and smart grids.
- Network Slicing: Network slicing runs multiple logical end-to-end networks as independent business operations over shared physical infrastructure.Each slice is instantiated from a predefined network slice blueprint.
- Design Challenges: RAN slicing faces spectrum limits, especially when dedicated carriers prevent multiplexing gains.Unlike fixed slices, radio slices cannot scale freely by simply adding hardware resources.
- Design Challenges: Heterogeneous RATs and spatially constrained resources may prevent every application from receiving its preferred technology or location.Examples include low-latency Tactile Internet resources and location-specific industrial computation for security.
- Design Challenges: Sharing more RAN elements can improve slice efficiency but increases information-exposure risks and may conflict with tenant security requirements.Emergency services, remote surgery, and vehicular control may constrain partitioning or prevent hardware sharing.
- Design Challenges: Because spectrum cannot be overprovisioned, infrastructure providers need admission and allocation algorithms rather than an “always accept” policy.The stated objective is maximizing overall utility across tenant slice requests.
C. Network Slicing Applications and Profitability
Network slicing is presented for mission-critical smart-factory and Tactile Internet applications, while virtualization and sharing support practical deployment and potential operator revenue. The section connects localized, isolated slices with resource utilization and inter-operator sharing.
- Slicing Applications: Smart-factory communications and the Tactile Internet use wireless links to convey force or touch information for remote manipulation.Both applications involve remote real or virtual objects and have mission-critical reliability and security requirements.
- Slicing Applications: Virtualized network elements can be instantiated near the communication path, reducing propagation delay and latency.The remote-surgery example illustrates how virtualized elements support a more direct path than fixed network elements.
- Slicing Applications: Slicing supports reliability through reserved resources and security through tenant isolation and sandboxing.Slices can also operate locally within a factory to support data privacy while coordinating with public MNO slices.
- Profitability: Network slicing is assessed as a way to address operator underutilization alongside high CAPEX and OPEX.The motivation is to improve the economic profit potential of network deployment.
- Profitability: Cooperative slicing and inter-operator sharing can use unutilized resources for another operator’s slice while supporting scalability.The example contrasts operator A’s spare resources with operator B’s broader-coverage, lower-resource requirement.
D. Related Work
Earlier work studied isolated slices that reserve dedicated RAN elements for particular services. 5G network slicing extends this idea toward flexible sharing that seeks multiplexing gains while retaining isolation.
- Related Work: Earlier network-slicing studies focused on isolated slices with dedicated RAN elements fully reserved for particular services.Advanced virtualization motivates more flexible sharing models.
- Related Work: Flexible sharing aims to achieve multiplexing gains while preserving isolation and separation.The Network Virtualization Substrate is introduced in this context.
E. Our Contribution
The paper develops architectural principles for network slicing across 5G RAN and core networks. It emphasizes coexistence between dedicated and shared slices and the role of Software Defined Mobile network Control.
- Our Contribution: The work studies network slicing using the 5G NORMA mobile-network architecture framework.It focuses on principles for accommodating slicing in the 5G ecosystem.
- Our Contribution: The paper addresses coexistence of dedicated and shared slices within a common network architecture.It also examines implementation in the RAN and core network, emphasizing Software Defined Mobile network Control.
II. MOBILE NETWORK SLICING ARCHITECTURE
The architecture combines dedicated and shared network functions across end-to-end slices. Dedicated functions form dedicated sub-slices, while shared functions are coordinated in common sub-slices.
- Network slices use partially shared infrastructure containing generic NFVI resources and dedicated RAN hardware.
- Common network-function candidates include distributed eNBs and RAN schedulers, plus HSS or mobility management in the core network.
- Dedicated functions form sub-slices controlled by SDM-C, while shared functions form common sub-slices controlled by SDM-X.
- Dedicated and shared sub-slices are combined to form end-to-end mobile network instances.
B. End-to-end network slicing: Common and dedicated network functions
SDM-X coordinates shared functions and resources while preserving slice-specific policies and service guarantees. RAN slicing maps traffic and radio configurations to slice requirements without changing fundamental RAN paradigms.
- SDM-X manages shared network functions and resources to improve efficiency while guaranteeing individual SLAs.
- SDM-X dynamically assigns resource masks from a shared resource-block pool, enabling tenant scheduling while preserving slice isolation.
- The NS-SF selects a slice per user and configures the RAN–CN interface to route control and user traffic accordingly.
- A multi-connectivity anchor distributes traffic according to slice policy and applies slice-specific security keys.
- Radio resource management configures protocol stacks and QoS according to slice requirements, including multi-connectivity for high-throughput slices.
- Slice A uses two radio connections while slice B uses one, showing policy-based mapping without changing fundamental RAN paradigms.
B. Multiplexing network slices in RAN
RAN slicing multiplexes multiple slices over shared spectrum while tailoring protocol stacks and radio resources to service requirements. The proposed 5G radio uses time-frequency tiling to allocate resources to slices.
- A common RAN can share spectrum among three slices, each retaining its own RAN and core-network part.
- Slice-specific RRC can tailor the user-plane stack, such as omitting IP and header compression for low-delay services.
- Different slice flows can receive distinct treatment through flexible numerologies and semi-persistently reserved resources for deterministic traffic.
- Lower-layer radio interfaces are harder to configure slice-specifically because 5G must inherently coexist with diverse services.
- 5G radio tiling divides time-frequency resources into units that can be allocated according to slice requirements.
C. Exemplary architecture with shared RAN slices
The shared-RAN architecture offers three levels of slicing customization, ranging from separate protocol stacks with limited PHY sharing to a common RAN managed through SDM-X.
- The architecture integrates shared RAN slicing through three implementation options.
- Option 1: Option 1 gives each slice an individual RAN protocol stack through the upper PHY, sharing only the lower PHY and coordinating access via SDM-X.
- Option 2: Option 2 provides slice-specific PDCP, RLC, and RRC, while SDM-X controls MAC access subject to fairness and SLA-based QoS guarantees.
- Option 3: Option 3 lets two operators use the same RAN as a shared resource through the SDM-X CN–RAN interface, without further radio-resource-management customization.
D. Flexible RAN Technologies as Enablers for Shared RAN
Flexible RAN technologies support shared network slicing by combining multiple connectivity options, shared context, and edge-based service processing. These approaches improve performance or enable diverse service configurations, while creating coordination and architectural challenges.
- Multi-connectivity: Multi-connectivity connects a UE through multiple cells or PHY interfaces to aggregate throughput or increase reliability.The central challenge is enforcing differentiated QoS, prioritization, and service requirements through a single scheduler.
- Multi-connectivity: Common PDCP and common MAC are two multi-connectivity options within the exemplary flexible RAN architecture.In the common PDCP approach, PDCP is shared across radio legs while lower protocol layers remain separate logical entities.
- Multi-RAT and mmW technology: Multi-RAT and mmW deployments use multi-connectivity to support mobile broadband and machine-type applications across diverse architectural conditions.Relevant conditions include transport capabilities, low-band integration, and propagation impairments.
- User-centric signaling: User-centric signaling organizes radio nodes into a User Centric Connection Area with one anchor node sharing user context across the area.Core-network bearers terminate at the anchor node, supporting services with short, sporadic, and delay-tolerant packets.
- Mobile edge computing and edge cloud processing: Mobile edge computing places services closer to users, motivating dynamic service chaining with edge locations and VNFs within network slices.Edge infrastructure can also support storage, computation, and dynamic service creation for verticals and over-the-top providers.
IV. CONCLUSIONS AND FURTHER CHALLENGES
The paper reviews network-slicing implementation features, dedicated and shared slice mapping, and RAN and core-network integration. It finds strong potential for addressing diverse 5G requirements, while emphasizing that the technology remains immature and requires further development before standard adoption.
- Conclusion: Network slicing offers strong potential for addressing the diverse requirements of future 5G systems.The analysis connects this potential to implementation features and the coexistence of dedicated and shared slices across RAN and CN.
- Conclusion: The paper analyzes dedicated and shared slice mapping and implementation-specific network-slicing aspects across the RAN and CN.It gives special focus to the connection between network slicing and RAN concepts.
- Further challenges: Network slicing remains at an early development stage, so maturity and adoption in network standards are still expected to require substantial further work.The conclusion cautions that a long path remains before the technology becomes mature and is adopted by standards.
VII. BIOGRAPHIES
This section provides biographical information about the paper’s authors, including their professional affiliations, research roles, and technical backgrounds.
- Cinzia Sartori: Cinzia Sartori is a principal expert in end-to-end mobile network architecture focused on 5G at Nokia in Munich.She previously led Nokia Siemens Networks’ Self-Organizing Network Research and Standardization project until mid-2013.
- Cinzia Sartori: Sartori co-authored the book ‘LTE Self-Organizing Network’ and previously worked across network telecom, operations, radio-resource management, and SS7.Her earlier affiliations included Nokia Siemens Networks, Siemens, and GTE.
- Vincenzo Sciancalepore: Vincenzo Sciancalepore holds M.Sc. degrees in telecommunications engineering and telematics engineering and double Ph.D. degrees.He received the M.Sc. degrees in 2011 and 2012 and the Ph.D. degrees in 2015.
- Vincenzo Sciancalepore: Sciancalepore worked on intercell coordinated scheduling and device-to-device communication before becoming a research scientist at NEC Europe.His current research involves network virtualization and network slicing challenges.