case study: 4g lte son field trial in suffolk, east...

Case Study: 4G LTE SON Field Trial in Suffolk, East Anglia

Afolabi Agbede, BT

Wireless & Mobility Consultant

19th Oct. 2016

© British Telecommunications plc

Introduction

FMC

femtocell

BT (represented by Niche) secured a licence for 2x15MHz of FDD & 25MHz of TDD 2.6GHz spectrum


Development Components

Mobility

Voice

Management

Access

Control

QoS

Software

Security

Synchronisation

SON

Hardware

Ethernet

Interoperability

Capacity &

Performance

Radio


Trial Objectives

1

2

3

4

Validation of fundamental SON features - TPM, PCI Selection, REM Scan & ANR

Evaluation of Plug & Play self-configuration of HeNBs and Remote Management via TR069

Evaluation of SCEP Certificate enrolment and Network Listen synchronisation

Evaluation of device technology interoperability and User experience

To validate key SON self-configuration features & parameters work as expected in a

field deployment.


4G LTE SON Trial

• Field Trial Location: Ipswich Town Centre

• Built up Area, MDU; Trialists typically within block of Residential Flats

• Trialists were within proximity of each other (< 100m)

• HeNB with Qualcomm Ultra-SON feature set

• All HeNBs managed and interrogated remotely via TR-069

• All HeNBs are co-channel (No Macrocell Mobility; LTE Band 7 Only)


Intra-Freq REM

Intra-Freq REM Scans successful observed (Boot Up & Periodic)

Boot up REM Scan configurable

Periodic REM Scan configurable

HeNB logged timestamp of each successful REM Scan


TPM

Dynamic adjustment of HeNB downlink transmit power

(via REM and averaged UE measurements)

Transmit power chosen after downlink transmit power selection stored as

a read only TR-069 parameter

During REM Boot scan & Periodic REM, co-channel Neighbour RSRP is

measured to select its own operating transmit power


PCI Selection

The HeNB must support Auto PCI & Auto Root Sequence Index (RSI)

selection

The HeNB has the ability to auto-select a PCI from a PCI pool specified

via OAM.

Non-conflicting PCIs are selected from a PCI pool with a uniform

distribution

HeNB successfully completed PCI conflict resolution (When a PCI Conflict

was forced)

UE based PCI confusion detection & resolution successfully observed

(When a PCI Confusion was forced)

UE Based PCI collision detection & resolution observed successfully

(When a PCI Confusion was forced)


Intra-Freq ANR

UE Assisted ANR fully supported

Intra Freq ANR supported.

HeNB is capable of recording co-channel LTE Neighbours

The NRT entry timeout value is remotely configurable


Network Listen synchronisation

Primary Sync Source: NL

Fallback Sync Source: NTP

HeNB frequency synchronised from the air interface using NL (3G/4G)

Implemented Priority: LTE(4G) > UMTS(3G)


SCEP Certificate Enrolment

Auto-enrolment process with the CA platform: HeNB obtains its unique

certificate from BT Trustwise using SCEP

HeNB Uses Simple SCEP to manage its own IPSEC certificates

(Certificate status check, Certificate enrolment, Certificate renewal,

Certificate rollover, CRL check)

PKI Managed by BT’s Trustwise Certificate Authority (CA)

X.509 digital certificate: Primary authentication mechanism used by the

HeNB to the SeGW

SCEP parameters configurable via ACS


Summary and Key Message

Plug & Play Auto-configuration Trial

• SON is key

• Automation and “zero-touch” configuration equally important (ACS, Remote Mgt, etc)

Confidence to support volume rollout

• Reduced OPEX and CAPEX

Self-Install and ease of deployment benefit

• Positive user experience


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