Business drivers and trade-offs between Small Cells and ... · PDF fileEricsson RBS 6201 © 2015 ThinkSmallCell Ltd. Current Industry Terminology: ... Refarming to LTE may require

© 2015 ThinkSmallCell Ltd.

Title

Business drivers and trade-offs between Small Cells and RAN Virtualisation

David Chambers Senior Analyst, [email protected]

Cambridge Wireless Small Cell SIG – 24 Sep 2015


Agenda

• RAN Virtualisation

• RAN Splitting

• Mobile Edge Computing

• Trade-Offs

• Conclusion


Custom to Commodity


Computer VirtualisationBefore After

Different hardware platforms Racks of common hardware

Different Operating Systems Can be configured for same/different

Different Database Versions Can be configured same/different

Fault tolerance vs Standalone High availability through SW and HW

Proprietary Hardware Standardised/Commodity

Separate sets of spare parts Common

Diverse set of maintenance procedures(hardware and software)

Common

Inflexible, expensive Flexible, scalable, cost efficient


Computer VirtualisationBefore After

Different hardware platforms Racks of common hardware

Different Operating Systems Can be configured for same/different

Different Database Versions Can be configured same/different

Fault tolerance vs Standalone High availability through SW and HW

Proprietary Hardware Standardised/Commodity

Separate sets of spare parts Common

Diverse set of maintenance procedures(hardware and software)

Common

Inflexible, expensive Flexible, scalable, cost efficient


Before After

“Telecom Appliance” Software Defined Network

High Availability High Availability

Integrated call control and media flow Separate control/media paths

Lack of scalability Highly scalable on demand

Costly to buy and maintain Cost effective to buy/maintain

Applied to Telecom Core Networks

Siemens MSC 2009: Hilman Asmarahadi EPC 2015: Cisco


Before After

“Telecom Appliance” Software Defined Network

High Availability High Availability

Integrated call control and media flow Separate control/media paths

Lack of scalability Highly scalable on demand

Costly to buy and maintain Cost effective to buy/maintain

Applied to Telecom Core Networks

Siemens MSC 2009: HilmanAsmarahadi

EPC 2015: Cisco


Our view: RAN Virtualisation = SDRSoftware Downloadable Radio

• Multi radio technology (Multi-RAT)

• Same hardware for 2G, 3G, LTE

• RAN virtualisation in the sense that same hardware for any RAT

• Some small cells also allow 3G/LTE configuration but most are cost engineered for specific markets

Ericsson RBS 6201


Current Industry Terminology:RAN Virtualisation = RAN Splitting

Goal is to centralise more of the RAN functionality• But many functions are closely tied into hardware and

location• RF heads must be distributed on site• Enormous bandwidth for fronthaul of raw RF• Timing/latency issuesKey Benefits• System spectral efficiency• Lower field support costs


Possible RAN Splits

Source: Small Cell Forum

FronthaulBackhaul

10Gbps

0.1Gbps


RAN split vs Fronthaul

Source: Small Cell Forum Doc 159

Small Cell Forum defines an nFAPI interface using PDCP-RLCBandwidth/Latency above required per LTE Carrier

By comparison, CPRI used for Remote Radio Heads requires 2.5Gbps up to 10Gps (with compression, about 1Gbps)


Macrocell Evolution Scenario

• Build out adequate fronthaul capacity

– Ideally dark fibre: 1 fibre = 7 CPRI links

– Other options exist

• Relocate BBUs to central facility

• Optimise BBU interworking


Products for new installations

Outdoor• Nokia Flexi-Zone• Airspan Symphony

Indoor• Airvana OneCell• Huawei Lampsite• Ericsson RadioDot


C-RAN Trade-offs

Benefits Disadvantages

Less space at macrocell sites, makes little or no difference for small cells

Much higher bandwidth for fronthaul, typically Gbpsand typically needs fibre

Higher spectral efficiency = fewer radio heads Same software and operational

Simpler equipment at radio head, fewer site visits, lower OPEX

Still requires similar hardware at RF node

Possible energy savings due less A/C Tight timing/sync alignment crucial


Mobile Edge Computing

• Mobile Edge Computing places some core functions close to the user– Reduced latency– Local intelligence– Caching to reduce backhaul

requirements

• RAN splitting restricts how close the core functionality can be to the user

Core

eNodeB

RRH

C-RAN

Core


Capacity Growth OptionsOption Action Issues Potential

Capacity

More Spectrum Buy/Release new spectrum

Use unlicensed bands

Spectrum very expensive and scarce.Strong pushback from Wi-Fi communityNewer smartphones, antennas/RAN kit

3x

Spectrum Efficiency Refarm to 3G, LTEHigher co-ordination between cells (CoMP, eICIC)

Refarming to LTE may require VoLTE and/or newer phonesC-RAN needs high fronthaulbandwidth

3x

Spatial Reuse Deploy Small Cells Perceived to be costly/difficultIntroduce new vendors/back office processes

100x

Augment with Wi-Fi Integrate trusted and untrusted Wi-Fi

Complex operational integrationQuality can be difficult to manage

3x – 100x

HetNet Orchestration Configuration preferences, SON,traffic shaping/steering

Take into account device capabilitiesC-SON/D-SON/Wi-Fi may conflict

2x


Conclusions

• The name is wrong: RAN virtualisation is mostly about RAN splitting or partitioning

• Most relevant for a few, very high capacity environments (stadiums, transport hubs, urban hotspots) or within Enterprise buildings

• Trade-off is needed between high capacity fronthaul (fibre), lock-in to single vendor vs fewer radio heads/small cells

Documents

Business drivers and trade-offs between Small Cells and ... · PDF fileEricsson RBS 6201 © 2015 ThinkSmallCell Ltd. Current Industry Terminology: ... Refarming to LTE may require