Software defined and virtualized wireless access open issues and perspectives

Software defined and virtualized wireless accessopen issues and perspectivesFabrizio Granelli (granelli@disi.unitn.it)

FP7 PACE Project Workshop on "Path Computation Element and beyond: innovating control and management functions towards fully reconfigurable software-centric networks"Table of ContentsIntroductionSDNWirelessExtending SDN over wirelessVirtualizing wireless accessNFVTest case: SDN for interference controlE2E SDNStandardizationConclusionsIntroductionComputer networks play a very important role in our day to day lifeAs the number of users increases so does the number of network devicesChallenges:Configuration and managementbecomes costlySystem updates are verydemandingLowers the pace of innovation

Introduction (contd)Why?The control logic (intelligence) is embedded to every deviceHow it could be solved?Software-Defined Networking (SDN)

What is SDN?Newly emerging network architecture paradigmPromises innovation in terms of:Network programmabilityHigh-level of abstraction

Introduction (contd)How is it achieved?By separating the control-plane and data-plane with a well-defined programmable interface to provide:Centralized global view of the networkEasy configurability and manageabilityFlexibility, scalability and capability of reconfiguration of different network segments

Introduction (contd)

Why wireless?Mobile data traffic is also booming due to:

Why wireless?

Why wireless? (contd)Device bandwidth consumption profile*Growth in the number of devices growth in mobile data trafficDeviceTrafficM2M6 * Wearable Devices7 * Smartphones49 * Tablets127 * Laptops227 *

To account these issues, programmability of mobile networks is needed:Allocating non-overlapping frequency bandsMonitoring interferenceCoordinating handoversConfiguration and management*Cisco and/or its affiliates, Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 20132018, White Paper, February 5, 2014 Extending SDN to wireless

Extension of the NaaS concept to include wirelessGoogle Project Fi

Wireless access virtualization perspectivesFlow Oriented PerspectiveAlso, mobile network virtualizationManagement and scheduling of different flows on different slicesImplemented as overlay (OpenRoads, vBTS) or via internal scheduler (NVS, vLTE)Protocol Oriented PerspectiveCustomize and manage multiple wireless protocol instances on the same radio HW (OpenRadio, SORA)Spectrum Oriented PerspectiveRF bands and raw spectrum are slicedWireless virtualizationExtension of Service Awareness and Functions Modularity to the wireless domainDecoupling of management and data planes (CAPWAP)Virtualization using SDRsBaseband processing divided into programmable processing and decision planesWLAN VirtualizationConnecting NICs to different networksCloudMACCellular Base Station VirtualizationDifferent schedulers for different slicesWireless Spectrum VirtualizationSpectrum reshaping (Spectrum Virtualization Layer)

Enabling SDN over wirelessThe idea is to augment the capabilities of WiFi (Virtual WiFi)14Enabling SDN over wireless (contd)

Efficient management and allocation of network resources (NetShare)Enabling SDN over wireless (contd)

- Additional flexibility and efficiency in resource allocation16Enabling SDN over wireless (contd)

CROWD architecture (www.ict-crowd.eu)Extremely dense and heterogeneous scenarioMitigation of intra-system interference, opportunistic channel usage, energy efficiencyControl through CROWD Regional Controller and CROWD Local Controller17Enabling SDN over wireless (contd)

Enhancing IP multicast over 802.11 networksMultiflow converts multicast tx into unicast, to optimize channel availability18Test case: SDN for Interference controlEven though the problem of interference was studied for decades at both PHY and MAC layers, so far no satisfactory solution emerged.

Objective:To come up with a framework for interference control (i.e., manage and avoid) to mobile networks by adopting the SDN paradigm

(*) Anteneh A. Gebremariam; Leonardo Goratti; Roberto Riggioy; Tinku Tasheed; Fabrizio Granelli, A Framework for Interference Control in Software-Defined Mobile Radio Networks, IEEE CCNC 2015. How?By exposing/abstracting the lower layers of the protocol stack (i.e., PHY and MAC) in order to make system parameters available to the controller or applicationsProviding an efficient resource scheduling scheme to control interference

System Architecture

Interference control frameworkSDN for Interference control (contd)The Goal is the design and implementation of the interference control framework20

The selection of H is doneby the central controller based on the channel feedbackinformation of the UEsY can be represented by atuple of parameters, , representing an abstraction of the resources assigned to a data stream X

PORTIG represented by a pair (V, E)IG construction:Based on the historyMicro-probing

Interference Graph (IG)SDN for Interference control (contd)The details of each block in the interference control frameworkPORT :- motivated by the switch port concept, where the switch input ports are mapped in to an output port based on the forwarding table.In a similar manner we can use the same concept in the wireless domain to provide the flexibility of selecting the mapping H from the centralized controller.

Interference Graph (IG) :- models the interference among communication links. Its represented by two tuples (V, E); where V represents the UEs and E represents the edge connecting the interfering transmitter to the receiver (i.e., UE). From the figure above, the purple lines represent the IG and the black solid lines represent the connectivity graph.IG construction:I, By collecting information for a certain period from all communication linksii, Micro-probing: by injecting traffic to the network (accurate and very demanding)

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Conflict Graph constructionWhat are weights assigned for each edge?

The maximum allowed interference level at the receiver (using Physical Interference Model) is:The maximum allowable interference contributionof the kth interfering link on terminal XR(i):Conflict Graph (CG)Sm represents a set of communication links that could be active at the same time, considering the following expression is satisfied:

SDN for Interference control (contd)Where is the threshold SINR, 2 is the additive noise, Xi and XR(i) represents the transmitter and receiver location 22The optimizer:Goal: to reduce the weights in a certain transmission link in the CGHow? Efficient resource scheduling: Integer Linear Problem (ILP)Objective function minimization of the weights (i.e., minimizing the aggregate interference)

Constraints :

decision binary variable, which is 1 if link li uses MCS (modulation and coding scheme) m in RB (resource block) r or 0 otherwiseSDN for Interference control (contd)Where: L- represents the transmission links (UE, eNB) pairs R- represents the resource blocks (RBs) (frequency, time, space) M-the Modulation Coding Scheme

i,k,r,m :- is a decision binary variable, which is 1 if link li uses MCS m in RB r or 0 otherwisethe power constraint sets the interval for the transmission power levelTP constraint makes sure that each link achieves its throughput demands23End-to-End SDNTo enable combined management of wireless and wired segments of the networkAdvantages:Unified management of the networkUnified policy enforcementEnabler for NaaSPerformance improvementVendor interoperabilityCustomized applications through SDN (northbound) APIsCurrent Standardization Efforts on SDNIETF Forwarding and Control Element Separation (ForCES) WGOpen Network FoundationPushing OpenFlowInterfaces between (1) applications and controller and (2) controller and switching infrastructureITU-T SG13 (Future Networks) and SG11 (SDN signaling)IRTF Software Defined Networking Research GroupETSI SDN/NFV

Standardization of wireless NVFsSeveral interesting scenarios of wireless in the future5G calls for heterogeneous wireless networkingSDN could come in the picture to enable efficient management of 5G infrastructuresStandardization could be two-fold:Standardizing WHAT is virtualizedStandardizing the WAY we compose virtualized entitiesConclusionsSDN is expected to be hot both in wireless as well as in wireless-cum-wired scenarios5G could represent a suitable scenario, including hetnets and softwarizationDifferent opportunities for standardization

For more info: F. Granelli, et al. Software Defined and Virtualized Wireless Access in Future Wireless Networks: Scenarios and Standards, IEEE Communications Magazine, in press

Software defined and virtualized wireless accessopen issues and perspectivesFabrizio Granelligranelli@disi.unitn.it Any questions?