Julius Robson, Lead NGMN Small Cell Backhaul

Cambridge Broadband Networks Ltd

ICT KTN & Cambridge Wireless Radio Technology SIG

3 October 2012

1

NGMN Requirements for

Small Cell Backhaul

Next Generation Mobile Networks

jrobson@cbnl.com

The NGMN Alliance

The NGMN Alliance is developing, consolidating and communicating

operator requirements to ensure that customer needs and expectations

on mobile broadband are fulfilled.

The Alliance actively drives global alignment, harmonisation and

convergence of technology standards and industry initiatives with the

objective to avoid fragmentation and to guarantee industry scale.

A global presence has been established that comprises a leadership

network of more than 60 partners: Operators, Vendors, and Universities.

Several Cooperation Partners support the NGMN Alliance in projects,

conferences, and through liaison statements

The joint work programme covers key topics on Networks, Devices, and

Application Enablers as well as Spectrum Demand, SDO Alignment and

Technology Evolution.

2

…driving industry alignment

The Alliance is supported by the key

industry players

More than

50% of world

wide

subscribers

More than

90% of

worldwide

equipment

…closely cooperates with key industry

organisations and research initiatives

4

NGMN

Requirements

Testing &

Trials

NGMN cooperation partners and organisations included in NGMN liaisons

Work focus on deployment, operations and

future technology enhancements

5

Share experiences from

deployment and

operations to improve

performance

Provide requirements to

drive future technology

enhancements

Ensure global alignment

to avoid fragmentation

of standards and

solutions

Overview of NGMN Work Areas

Standards

Alignment

LTE-FDD/TDD Convergence

Antenna design and Performance Measurement

Backhaul Solutions

Centralised RAN

Heterogeneous Networks Evolution and Operations

QoS, QoE Definition and Measurement

Smart Networks

Global Spectrum Harmonisation

Bandwidth aggregation

Standards evolution

Technology evaluation

Voice over LTE

Multi-mode, multi-band devices

Certification

SON use cases

OSS interfaces

OSS for Converged Networks

Operational

Efficiency

Devices

Network

Architecture

Application

Enablers

Spectrum

Deployment

Aspects

Innovation

Dialogue

Cognitive

Radio

Integrated

QoS

Management

coming

Security

In LTE

Backhauling

Feb

2012

NGMN Backhaul Evolution Project

6

Optimised

Backhaul

Requirements

2008

Small Cell

Backhaul

Requirements

Jun

2012

http://www.ngmn.org/nc/downloads/techdownloads.html

Original

macrocell

focus

Small cell

specific Detailed

Refinement

aspects

Guidelines for

LTE Backhaul

Traffic

Estimation

Jul

2011

Motivation for Small Cell Backhaul Project:

Operators are currently considering deploying small cells as a

complement – or possibly alternative to their macro cell networks

Small cells will have different backhaul needs to macros

and many new solutions are being proposed to meet them

yet it is still uncertain which ones will work best

The purpose of this study was to help move the industry forward

by clarifying consensus around operators’ requirements for small

cell backhaul

These will inform the industry as to what operators need,

and aid in the selection and comparison of solutions

7

Where do backhaul requirements come from?

8

• Small cells can be deployed in a number of ways depending on the

network issue they are aiming to solve

• The purpose of backhaul is to connect the small cells to the core with

the required Quality of Service

• Backhaul requirements depends on the use case for the small cell

Core Services

Small Cell

RAN

Small Cell

Backhaul

Transport Network

Overview

9

Compare

Solutions

for small cell

backhaul

Define

Small Cells &

Use cases

within scope of

this study

Define

Requirements

for small cell

backhaul

Operator deployed

-Capacity hot spot

-Coverage not spot

HSPA+, LTE, WiFi

:

:

Capacity

Coverage

Availability

Physical design

:

:

Fibre

NLoS <6GHz

Microwave PMP/PTP

60/80GHz

TVWS

:

Overview

10

Compare

Solutions

for small cell

backhaul

Define

Small Cells &

Use cases

within scope of

this study

Define

Requirements

for small cell

backhaul

Operator deployed

-Capacity hot spot

-Coverage not spot

HSPA+, LTE, WiFi

:

:

Capacity

Coverage

Availability

Physical design

:

:

Fibre

NLoS <6GHz

Microwave PMP/PTP

60/80GHz

TVWS

:

Small Cell Use Cases

11

Operator

(Public Access)

Femtocells

Home / Enterprise

Coverage

Targeted

Hot Spot

Non-targeted

‘Peppered’

Outdoor

Not-spot

Indoor

Not-spot

Small cells

Deployed by

Capacity

Consumer and

Enterprise deployed

Coverage &

QoE enhancement Primary

Motivation

Use Case

Small Cell Use Cases

Source: “Small Cell Deployment Strategies”, CBNL June 2011, http://goo.gl/xLtcR

Focus of NGMN requirements

Coverage or Capacity

A Definition:

12

macro

…depends on presence of existing macro coverage:

Not spot Hot spot

No existing macro coverage

Small cell introduces service Macro coverage provides service

But QoE is poor during busy times

More CAPACITY needed Basic COVERAGE needed

Capacity: Targeted or Peppered?

13

1) Un-served demand Hot spot ( existing macro cov)

Not spot (no existing macro cov)

3) Backhaul Connectivity Wired connection

LoS from Hub

NLoS with sufficient Tput 2) Suitable site Power, access, etc

coverage

How well can we match small cell coverage to demand in practice?

A blanket approach might be more cost effective in some cases

demand

Overview

14

Compare

Solutions

for small cell

backhaul

Define

Small Cells &

Use cases

within scope of

this study

Define

Requirements

for small cell

backhaul

Backhaul Requirement Categories

15

The usual suspects In small cell flavours

Small Cell Specific

Capacity

provisioning

Coverage &

Connectivity

QoS

Support

Physical

Design

Sync

Security

Network

Architectures

OAM

Ease of

Installation

Cost

Availability

NGMN’s existing macro backhaul requirements have

been updated and new small cell specific items added

Coverage and Connectivity

16

Macro

Typical Small

Cell locations

Small cells typically below

rooftop 3-6m above street

level

In a Het-Net scenario,

macrosites may double up as

aggregation sites for small

cells

‘Last mile’ backhaul therefore

provides connectivity

between macro sites and

small cell sites

Connection must meet QoS

requirements…

Coverage means providing connectivity between small cell sites

and local aggregation points which meets QoS requirements

Quality of Service Requirements

Consumers must have same QoE (Experience) over

small cells as over macrocells

17

macro Hot spot

Not spot

Backhaul availability can be relaxed

Capacity must not be limited by backhaul

Availability cannot be relaxed

Capacity can be relaxed

Backhaul QoS requirements depend on deployment scenario

Calculating Backhaul Traffic

Consider user plane traffic + overheads

18

S1 User plane traffic

(for 1 cell)

+Control Plane

+X2 U and C-plane

+OA&M, Sync, etc

+Transport protocol overhead

+IPsec overhead (optional)

Core network

RAN

Small Cell Backhaul Provisioning

Recommended provisioning based on small cell throughput

plus overheads for X2, IPsec transport etc.

Provisioning for N small cells = Max(peak, N x mean)

Capacity should not be limited by the backhaul at Hot-Spots

…but may be relaxed at coverage Not-spots

19

Key Assumptions: evaluation methodology based on "Guidelines for LTE Backhaul Traffic Estimation", NGMN Alliance, July 2011

U-plane Cell Tput based on NGMN simulations for macro cells scaled to represent the small cell environment

Overheads added for transport protocol, IPsec security and X2 where appropriate

Overview

20

Compare

Solutions

for small cell

backhaul

Define

Small Cells &

Use cases

within scope of

this study

Define

Requirements

for small cell

backhaul

Last Mile Backhaul Options

LOS/nLOS PTP

Macro BTS site

with fibre or MWR backhaul Line of Sight

microwave

cable/fibre

LOS/nLOS/

NLOS LOS/nLOS/

NLOS

small cell site

Small cells may connect via macro sites

A mix of wired and wireless and backhaul technologies (e.g. PTP, PMP, LOS,

n(ear) LOS, N(on)LOS, FTTx) will be needed to reach Small Cell BTS sites

Small Cells may be connected in chain, tree or mesh topologies

NLOS (PMP) nLOS

The main differences between small and

macro cell backhaul are in the last mile

Small Cell Backhaul Solution Types

22

Small Cell

Backhaul

Solutions

Wired

Wireless

DSL

Fibre

Satellite

TV White Space <800MHz

Non LoS <6GHz

Microwave 6-57 GHz

E-Band 64-85 GHz

60GHz 57-64 GHz

Spectrum Licensing

Dynamic + light

Area licensed

Unlicensed

Link licensed (PTP)

Area licenced (PMP)

Unlicensed

Light Licensed

Managed Service

Carrier Frequency

Small cell definition and scope of use cases

Backhaul Requirements

– Small cell network architectures

– Physical design

– Coverage and connectivity

– Capacity Provisioning (dimensioning)

– QoS support

– Synchronisation

– Availability and resiliency

– Security

– Operational, Management, Traffic Engineering

Backhaul Solutions

– Wired/Wireless LOS/NLOS etc

Requirement Statements

Small Cell Backhaul White Paper Download from: www.ngmn.org

23

Main contributors:

Summary and Key Messages

Backhaul is a key enabler for small cells, but there is uncertainty around which

solutions are suitable. The NGMN will help move the industry forward by clarifying

consensus around requirements

We focus on operator deployed, open access small cells and ‘last mile’ backhaul

Key messages:

– Cost per small cell backhaul connection will need to be much lower than for

macrocells, but consumer Quality of Experience cannot be sacrificed

– There is however scope to relax some aspects of backhaul offered QoS:

Availability may be relaxed for capacity sites at hot-spots

Capacity provisioning may be relaxed for coverage sites at not-spots

– Small cells dictate the following new requirements for backhaul:

Coverage down to street level sites with sufficient QoS

Secure and compact physical design for rapid low cost installation

– A toolbox of solutions may be needed to address diverse deployment scenarios

Our white paper captures these issues and defines a set of requirement statements

This can be a basis for further work by groups such as the Small Cell Forum and MEF

24

25

Thank you