Source-linked AI summary
Software-Defined and Virtualized Future Mobile and Wireless Networks: A Survey
Mao Yang, Yong Li, Depeng Jin, Lieguang Zeng, Xin Wu, Athanasios V. Vasilakos
TL;DR
Current mobile and wireless networks struggle with proliferating demand and diverse services because of architectural limitations. The paper surveys SDWN and WNV, their technologies and open issues, and their joint design, concluding that they can address these challenges while supporting gradual evolution.
Problem
Current mobile and wireless networks face challenges rooted in inherent design, including heterogeneous-network convergence, resource utilization, innovation, and diverse-service support.
Method
The paper surveys SDWN and WNV, analyzes their opportunities and technologies, examines open issues, and investigates their effective combination.
Results
SDWN and WNV are reported to benefit heterogeneous-network convergence, resource utilization, innovation, customized services, QoS and QoE, revenues, and smooth evolution with current networks.
Takeaways & Limitations
The paper concludes that combining SDWN and WNV is a promising direction for future mobile and wireless networks, though implementation still has open issues.
Abstract
from arXiv · showhide
With the proliferation of mobile demands and increasingly multifarious services and applications, mobile Internet has been an irreversible trend. Unfortunately, the current mobile and wireless network (MWN) faces a series of pressing challenges caused by the inherent design. In this paper, we extend two latest and promising innovations of Internet, software-defined networking and network virtualization, to mobile and wireless scenarios. We first describe the challenges and expectations of MWN, and analyze the opportunities provided by the software-defined wireless network (SDWN) and wireless network virtualization (WNV). Then, this paper focuses on SDWN and WNV by presenting the main ideas, advantages, ongoing researches and key technologies, and open issues respectively. Moreover, we interpret that these two technologies highly complement each other, and further investigate efficient joint design between them. This paper confirms that SDWN and WNV may efficiently address the crucial challenges of MWN and significantly benefit the future mobile and wireless network.
1 Introduction
Current mobile and wireless networks face growing pressure from proliferating mobile demand, heterogeneous systems, diverse services, and economic constraints. The paper argues that these problems stem from inherent architectural design and surveys SDWN and WNV as complementary opportunities for future networks.
- Proliferating mobile data demand and smartphones intensify pressure on traditional mobile and wireless networks.
- Heterogeneous networks suffer poor interworking, scarce-spectrum pressure, low resource utilization, hardware coupling, and inflexible control interfaces.
- Supporting multifarious services with the same network characteristics deteriorates users’ QoS and QoE.
- These challenges are rooted in vertical construction, distributed operation, hardware–protocol coupling, and IP addressing oriented toward fixed networks.
- The paper surveys SDWN and WNV, their challenges and technologies, and their possible combination for future mobile and wireless networks.
2 Challenges and opportunities for future mobile and wireless network
The section maps major mobile-network challenges to opportunities from SDWN and WNV. Together, the technologies support heterogeneous-network interconnection, resource sharing and optimization, programmability, customized services, and cost reduction.
- Challenge 1: Diverse heterogeneous networks: Vertical construction prevents heterogeneous networks such as LTE, WiMax, UMTS, and WLAN from interconnecting and being globally optimized.
- Challenge 1: Diverse heterogeneous networks: SDWN’s global network view enables dynamic forwarding, resource allocation, offloading, and cooperative strategies across heterogeneous networks.
- Challenge 2: Capability crisis: WNV improves resource and device utilization through shared substrate networks, while SDWN dynamically adjusts resources using requirements and real-time status.
- Challenge 3: Innovation expectations: SDWN makes networks programmable through open APIs, while WNV supports independent virtual networks for innovation without interfering with in-service networks.
- Challenge 4: Diverse service requirements: WNV enables customized services through virtual networks with appropriate characteristics, while SDWN adjusts configurations according to real-time QoS and QoE.
- Challenge 5: Traffic growth and cost: SDWN and WNV reduce costs through global optimization and resource sharing while introducing InPs, SPs, and open interfaces.
- The paper concludes that SDWN and WNV are promising ways to address crucial future mobile and wireless network challenges.
3.1 Software-defined network
Software-defined networking separates network control from packet forwarding and exposes control through programmable interfaces. Its paradigm supports simplified, flexible network devices and has been extended across multiple networking scenarios.
- SDN decouples the control and data planes, placing abstracted control functions in a logically centralized control plane.
- Network devices become simpler packet-forwarding and processing devices programmable through open interfaces such as OpenFlow.
- OpenFlow is the most recognized SDN realization, with standards maintained by ONF and implementations from vendors and controller projects.
- SDN is presented as a paradigm rather than an ossified architecture, enabling adoption across data centers, security, optical networks, and mobile wireless networks.
3.2 Software-defined wireless network (SDWN)
SDWN extends SDN’s separation and programmability to mobile and wireless networks. By combining centralized global information with programmable wireless devices and open APIs, it supports network control, customization, QoS, and heterogeneous access.
- SDWN applies SDN principles to mobile and wireless networks, targeting architectures and technologies suited to their characteristics.
- SDWN separates control and data planes, with a centralized controller allocating resources, scheduling devices, and configuring wireless parameters from global information.
- Network operators: For operators, SDWN provides global information that supports scheduling and adjustment of resource allocation, forwarding strategies, and wireless configurations.
- SDWN abstracts network functions through open APIs, enabling service providers to offer multifarious customized services while programming can guarantee QoS.
- End users: For end users, SDWN selects appropriate paths and access networks based on user, application, and network conditions, including simultaneous service by multiple networks.
- The paper attributes SDWN’s broader benefits to heterogeneous-network convergence, resource optimization, lower costs, innovation deployment, and benefits for network entities.
3.3 Ongoing research on SDWN
Ongoing SDWN research spans programmable wireless infrastructure, virtualization, lower-layer control, radio access networks, and software-defined mobile cores. Representative studies explore programmability, mobility, cross-layer optimization, centralized coordination, and cloud-based architectures.
- SDWN research remains in its infancy, with most work focusing on network architecture.
- Wireless infrastructure: OpenRoad separates network services from physical infrastructure using OpenFlow, NOX control, and FlowVisor virtualization, and evaluates WiFi–WiMax handovers.Its design primarily targets WiFi and lacks special cellular support.
- Wireless infrastructure: Odin provides programmable enterprise WLANs through a lightweight virtual access-point abstraction that separates association state from physical access points.The framework supports seamless mobility, load balancing, and hidden-terminal mitigation.
- Lower-layer control: OpenRadio and OpenRF investigate programmable wireless data planes and cross-layer MIMO control for evolving wireless networks.OpenRF maps high-level QoS requirements to physical-layer techniques, including interference nulling, coherent beamforming, and interference alignment.
- Radio access networks: SoftRAN and OpenRAN apply SDN concepts to radio access networks through virtual big-base stations, cooperative control, spectrum pools, and cloud processing.SoftRAN divides decisions between a central controller and radio elements, while OpenRAN establishes virtual base stations and virtual baseband units according to dynamic requirements.
- Mobile core networks: CellSDN, SoftCell, and MobileFlow address software-defined LTE core and carrier networks through network operating systems, local agents, traffic aggregation, and flow-based forwarding.
- Industry architectures: Huawei’s SoftCOM represents vendor interest in cloud-based future-network architectures that leverage SDN for network, operations, and business transformation.
3.4 Challenges and open issues
SDWN must support diverse wireless standards and cross-layer programmability while coping with fast-changing requirements, mobility, latency demands, and control-plane scalability. These conditions make flexible control and architecture-level scaling central open issues.
- SDWN must support diverse wireless standards while preserving their characteristics, enabling fast deployment, and allowing smooth evolution.
- Cross-layer software definition must decompose and abstract control functions from the network layer through the physical layer while preserving effective programmability.
- Application diversity and fast mobility produce rapidly changing network requirements and statuses, complicating flexible SDWN control strategies.
- SDWN must analyze service characteristics and network capabilities to expose appropriate, concise, and flexible open interfaces for service providers.
- Low-latency requirements, vulnerable wireless conditions, and mobility challenge QoS/QoE under logically centralized SDWN control.
- A sole centralized controller may become unable to handle incoming requests as wireless networks grow, so scalability requires architectural redesign rather than only faster hardware.
- Frequent handovers and complex mobile environments make tracking virtual-machine movement and reprogramming forwarding entries especially difficult.
4 Wireless network virtualization (WNV)
WNV extends network virtualization to mobile and wireless settings by running isolated virtual networks over shared wireless infrastructure. It separates infrastructure and service roles while addressing heterogeneous protocols, changing conditions, and diverse services.
- Network virtualization enables multiple isolated virtual networks to coexist on shared physical infrastructure and separates infrastructure providers from service providers.
- WNV applies this model to wireless substrates, with InPs operating physical mobile infrastructure and SPs leasing resources to create virtual networks for mobile services.
- Unlike wired virtualization, WNV must simultaneously support heterogeneous wireless protocols with substantially different technologies and performance parameters.
- Fast-changing wireless conditions and increasingly diverse services make timely virtual-network creation and management difficult.
- Advantages: WNV can improve heterogeneous-network resource utilization and energy efficiency by isolating multiple networks and letting service providers lease infrastructure resources.
- Advantages: Separate virtual networks can carry services with distinct requirements, such as low-latency voice or high-rate video, supporting customized QoS/QoE.
- Advantages: WNV supports network innovation testbeds and introduces an InP–SP economic model intended to reduce costs and increase revenues for both entities.
4.3 Ongoing research on WNV
WNV research covers wireless virtualization substrates, cellular and heterogeneous-network architectures, testbeds, resource allocation, and operational challenges. Open issues concern compatibility, dynamic mapping, allocation, fairness, and economic coordination.
- Early wireless virtualization: Early WNV studies mainly virtualized 802.11, including shared testbeds, time-division multiplexing, virtual wireless functions, software radio, and mesh virtualization.
- Cellular virtualization: Cellular WNV research includes WiMax resource reservations, virtual base stations, LTE air-interface virtualization, and general architectures with virtualized resources and controllers.
- Resource management: WNV research also addresses resource allocation and fairness, including stochastic-game models of InP–SP allocation and reservation frameworks.
- Testbeds and deployment: GENI, ORBIT, and mobile virtual network operators contribute to the development and deployment of WNV.
- Open issues: WNV needs flexible architectures and node virtualization that support multiple heterogeneous networks while guaranteeing isolation.
- Open issues: Dynamic mapping of services to virtual networks must account for rapidly changing service requirements and network status.
- Open issues: Virtual resource allocation remains difficult because it must balance efficiency, fairness, selfish behavior, and time-varying conditions.
- Open issues: WNV’s InP–SP economic model requires operating strategies that address complex network conditions and competing revenue and cost objectives.
5 Cooperation between SDWN and WNV
SDWN and WNV are presented as mutually complementary technologies whose joint design combines centralized software-defined control with network virtualization. The survey discusses architectures, FlowVisor-based slicing, virtualization approaches, and unresolved implementation challenges.
- 5. Cooperation between SDWN and WNV: SDWN centralizes control and separates control and data planes, while WNV adds scalability, flexibility, and improved resource utilization.The combination also supports optimal control, programmability, and customization.
- 5. Cooperation between SDWN and WNV: A feasible joint architecture introduces multiple SDWN controllers, each managing one virtual network and its corresponding flow rules.A physical network device may maintain multiple flow tables for different virtual networks.
- 5. Cooperation between SDWN and WNV: FlowVisor virtualizes a network into isolated slices by partitioning switch flow space and hosting one guest controller per slice.It provides both data-plane and control-plane isolation.
- 5. Cooperation between SDWN and WNV: WNV spans spectrum, access-device, and forwarding-device resources, making unified software-defined virtualization control difficult.Different virtualization dimensions require different implementation approaches.
- 5. Cooperation between SDWN and WNV: Joint SDWN-WNV deployment remains challenging because mobile and wireless conditions vary continuously and fine-grained designs increase implementation difficulty.The survey identifies a trade-off between finer-grained control and practical deployment complexity.
6 Conclusion
Mobile and wireless networks face fundamental challenges that simple modifications cannot resolve, motivating a survey of SDWN and WNV as promising technologies. The paper identifies benefits including heterogeneous-network convergence, improved resource utilization, service customization, QoS and QoE support, and increased revenue.
- Mobile Internet and multimedia-oriented services expose fundamental challenges rooted in the inherent design of current mobile and wireless networks.The passage states that simple modifications are unlikely to resolve these intractable issues.
- The paper surveys software-defined wireless networks and wireless network virtualization as two promising technologies for addressing mobile and wireless network challenges.
- SDWN and WNV support the convergence of heterogeneous wireless networks and improve resource utilization.
- SDWN and WNV facilitate network innovation from the network layer down to the physical layer while enabling customized services and QoS and QoE guarantees.
- SDWN and WNV can increase the revenue of all network entities.