UMTS_RF_Optimization_Workshop_Oct2004_v2.pdf

7/27/2019 UMTS_RF_Optimization_Workshop_Oct2004_v2.pdf

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OCTOBER 2004

WFI/o2 Workshop


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Isaac OMOTAYOProject Manager (WFI)

Jeremy RONNEVIGSenior Tools Support Officer (WFI)

Sandy LIENSenior UMTS Optimisation Engr (WFI)


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OBJECTIVE OF WORKSHOP Audience:

Delegates should be RF Engrs/Managers with good knowledge of UMTS Technology.

At the end of the course delegates will be able to: Understand basic UMTS network interfaces/protocols and UTRAN elements.

Understand the factors that can limit/hinder effective optimisation activity.

Understand UMTS optimisation process

Understand why RF Build Audit is essential

Understand Cell Shakedown/Site Verification

Define Cluster

Define and Understand difference between Optimisation and Acceptance route

Understand Cluster and inter-cluster optimisation

Understand why good neighbour definition is important

Analyse/Post process data using TEMS

Understand basic layer 3 messages

Identify and Plot Areas of Concern

High Active Set

Low Ec/Io

Low RSCP

Recommend Changes

Analyse and diagnose problem calls

Drop Calls

Failures


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Network Architecture


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UMTS Initial Deployment

BSS

PSTN

A IuCS

GMSC

VLRB

MSC

VLRB

MSC

PSTN PSTN

Gs

G

E

MS

CNGb

Uu

Um

Iur

IuPS IuPSIuCS

RNC

Node BNode B

RNS

lubis

GGSN

SGSN

BSS

BTSBTS

BSC

Abis

Node B

RNC

Node B

RNS

lubis

MEME

USIMUSIM

Cu

Um

BTSBTS

BSC

Abis


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UTRAN network elements and interfaces

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub

All shown interfaces (Iu, Iub and Iur) are standardised

in order to allow multi vendor networks


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UMTS Glossary

UTRA: UMTS Terrestrial Radio Access

Refers to the UMTS radio interface only.

AN: Access Network

The network that consists of all the BSS

RNS: Radio Network System

Equivalent to BSS

RNC: Radio Network Controller Equivalent to BSC

UTRAN: UMTS Terrestrial Radio Access

Refers to the UMTS BSS


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UMTS Glossary

Core Network NSS, with both the CS domain (inherited from MSc side), and the IP domain

(inherited by the GPRS side)

UE: User Equipment

MS Iu interface or reference point

Interface between the AN and CN: It has two real interfaces based on similarprinciples: the Iucs, for circuit switched, connects top the MSC, and the Iups,

for packet switched, connects to the SGSN Serving RNC

The RNC that has the RRC connection towards the terminal, and also the Iuconnection

Drift RNC

RNC that supports the serving RNC with radio resources when theconnection between the WCDMA RAN and the UE needs to use a cell orcells controlled by this RNC. This is a role that an RNC can take with respectto a specific connection. A drift RNC is connected to a serving RNC through

the Iur interface.


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UMTS Glossary

Uu

Interface between the UE and Node B

Iub

Interface between a RNC and its Node Bs. Equivalent to Abis

Iur New interface connecting two RNCs

Iu

Interface between RNC and CN.


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UMTS Glossary

Uu

Interface between the UE and Node B

Iub

Interface between a RNC and its Node Bs. Equivalent to Abis

Iur New interface connecting two RNCs

Iu

Interface between RNC and CN.


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UTRAN services to the Core Network

UTRAN is responsible for RRM

UTRAN is responsible for the radio connection mobility

UTRAN is responsible for providing Radio AccessBearers on the UTRAN to Core Network Interface, the Iu

interface

UTRAN is also responsible for the following functions: User Equipment (UE) location positioning (used in e.g. LCS)

Security functions


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Channel and Protocol Description


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Radio Interface Protocol Architecture

Radio

Interface

ProtocolArchitecture

Transport Channel (SAP)

Physical Channels

Logical Channel

L3

c

ontrol

c

ontrol

c

ontrol

c

ontrol

Logical

Channels

Transport

Channels

C-plane signalling U-plane information

PHY

L2/MAC

L1

RLC

DCNtGC

L2/RLC

MAC

RLC

RLCRLC

RLC

RLCRLC

RLC

Duplication avoidance

UuS boundary

BMC L2/BMC

RRC

control

PDCPPDCP L2/PDCP

DCNtGC

Packet Data Convergence Protocol:

Is only for PS domain services.


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Radio Interface protocol architecture

L2/MAC

L2/RLC

L1

RLC

MAC

L3RRC

PHY

TransportChannels

LogicalChannels

C-plane signallingU-plane information

GC Nt DC

RLCRLC

RLC

GCNTDCRRCRLC

MAC

General ControlNotificationDedicated ControlRadio Resource ControlRadio Link Control

Medium Access Control

UTRA Protocol Architecture


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Main MAC (Medium Access Control) functions Mapping between logical channels and transport channels.

Selection of appropriate transport format for each transport channel

depending on instantaneous source rate.

Priority handling between data flows of one UE.

Achieved by selecting high bit rate and low bit rate Transport formats for different for

different data flow.

Scheduling of broadcast, paging and notification messages.

Identification of UEs in common transport channels.

Multiplexing/demultiplexing of higher layer PDUs into/from transport

blocks delivered to/from the physical layers on common transport

channels.



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Main RLC (Radio Link Control) functions

Performing establishment, release, and maintenance of a RLC

connection.

Segmentation and reassembly of variable-length higher layer PDUs

into/from smaller RLC PDUs.

Protocol error detection and recovery

In-Sequence delivery of higher layer PDUs (Protocol Data Unit).

Flow control.

Ciphering.



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Main RRC (Radio Resource Control) functions

Broadcast of system information.

Establishment, release and maintenance of an RRC connection

between the UE and UTRAN.

Establishment, reconfiguration and release of radio access

bearers in the user plane.

Assignment, reconfiguration and release of radio resources for theRRC connection.

Control of requested QoS.


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Channel Definitions

Transport Channel:

the services offered by Layer 1 to higher layers

Transport channel defines the method and the characteristicsby which data are transferred over the air-interface

Physical Channel:

Physical channel, usually consisting of radio Frames andtimeslots, is the mechanism with which the data are

transferred over the physical resources such as code,frequency,phaseand time.

Logical Channel:

MAC layer provides data transfer services on Logicalchannels


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Logical Channel Structure

Synchronisation Control Channel (SCCH)

Broadcast Control Channel (BCCH)

Paging Control Channel (PCCH)

Dedicated Control Channel (DCCH)

Common Control Channel (CCCH)

Control Channel (CCH)

Dedicated Traffic Channel (DTCH)Traffic Channel (TCH)

ODMA Dedicated Control Channel (ODCCH)

ODMA Common Control Channel (OCCCH)

ODMA Dedicated Traffic Channel (ODTCH)

Common Traffic Channel (CTCH)

Shared Channel Control Channel (SHCCH)

(TDD)

(ODMA)

(ODMA)

(TDD)


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Transport Channels

Common Transport Channel

Common Transport Channels require inband identification of

the UEs when addressing particular UEs.

Dedicated Transport Channels:

Dedicated Transport Channels require the UEs to beidentified by the physical channel , i.e. code and frequencyfor FDD (code, frequency and timeslot for TDD).


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Transport Channels

Broadcast

Channel (BCH)(Downlink)

Transport Channels

Common ChannelsDedicated Channels

Downlink Shared

Channel(DSCH)

(Downlink)

Common Packet

Channel (CPCH)(Uplink)

Forward-Access

Channel (FACH)

(Downlink)

Paging

Channel (PCH)(Downlink)

Random-Access

Channel (RACH)

(Uplink)

Dedicated Channel (DCH)

(Down & uplink)

Fast uplink Signaling

Channel (FAUSCH)

(Uplink)


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Transport Channels

Common Transport Channels

BCH: The Broadcast Channel (BCH) is a downlink transport channel that is used tobroadcast system- and cell-specific information. The BCH is always transmitted over the

entire cell with a low fixed bit rate.

FACH: The Forward Access Channel (FACH) is a downlink transport channel. TheFACH is transmitted over the entire cell or over only a part of the cell using beam-

forming antennas. The FACH uses slow power control.

PCH: The Paging Channel (PCH) is a downlink transport channel. The PCH is alwaystransmitted over the entire cell. The transmission of the PCH is associated with the

transmission of a physical layer signal, the Paging Indicator, to support efficient sleep-

mode procedures.

RACH: The Random Access Channel (RACH) is an uplink transport channel. TheRACH is always received from the entire cell. The RACH is characterised by a limited

size data field, a collision risk and by the use of open loop power control.


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Channels

Logical Channels:

Broadcast Control Channel (BCCH), Downlink (DL)Paging Control Channel (PCCH), DL

Dedicated Control Channel (DCCH), UL/DL

Common Control Channel (CCCH), UL/DL

Dedicated Traffic Channel (DTCH), UL/DL

Common Traffic Channel (CTCH), Unidirectional (one to many)


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Channels

Transport Channels:

Dedicated Transport Channel (DCH), UL/DL, mapped to DCCH and DTCH

Broadcast Channel (BCH), DL, mapped to BCCH

Forward Access Channel (FACH), DL, mapped to BCCH, CCCH, CTCH,

DCCH and DTCH

Paging Channel (PCH), DL, mapped to PCCH

Random Access Channel (RACH), UL, mapped to CCCH, DCCH and DTCH

Uplink Common Packet Channel (CPCH), UL, mapped to DCCH and DTCH

Downlink Shared Channel (DSCH), DL, mapped to DCCH and DTCH


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Channels

Physical Channels:

Primary Common Control Physical Channel (PCCPCH), mapped to BCH

Secondary Common Control Physical Channel (SCCPCH), mapped to FACH, PCH

Physical Random Access Channel (PRACH), mapped to RACHDedicated Physical Data Channel (DPDCH), mapped to DCH

Dedicated Physical Control Channel (DPCCH), mapped to DCH

Physical Downlink Shared Channel (PDSCH), mapped to DSCH

Physical Common Packet Channel (PCPCH), mapped to CPCH

Synchronisation Channel (SCH)

Common Pilot Channel (CPICH)

Acquisition Indicator Channel (AICH)

Paging Indication Channel (PICH)

CPCH Status Indication Channel (CSICH)Collision Detection/Channel Assignment Indication Channel (CD/CA-ICH)


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PROTOCOLS

Network Protocols carried over Iu, Iur and Iub interfaces:

RANAP, RNSAP and NBAP

Radio Interface Protocols - radio protocol stack between the UE

and RNC through Node B

RRC, RLC, MAC and PDCP


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NETWORK PROTOCOLS

NBAP (Node B Application Protocol) Is carried over the Iubinterface (b/w RNC and Node B). Cell Config mgt

System info mgt

Resource Event mgt

Commom Transport channel mgt

Radio Link mgt and supervision

Measurement on common resources

Measurement on dedicated resources

RANAP (Radio Access Network Application Protocol) Is carried overthe Iu interface (b/w RNC and Core Network)

Relocation functions

RAB mgt Transport of non access stratum signalling messages (DTAP).

Paging functions

Security functions (Authentication, Ciphering and Integrity chaeck)

CN info broadcast


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NETWORK PROTOCOLS

RNSAP Radio Network Subsystem Application Protocol) Is

carried by Iur interface

Radio link mgt

Measurement reporting function

Transfer of Uplink and Downlink functions

Power control

Load mgt

Paging functions

Relocation functions.

S d fi iti


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Some definitions

Radio Bearer A service provided on top of the RLC layer

Radio Bearers have characteristics which depend essentially on the type of

RLC which is used and the underlying physical channel

Logical channels

A service provided by MAC to RLC

The underlying physical/transport channel may change in time

Transport Channels A service provided to the MAC layer by Layer 1.

is almost equivalent to Logical channels in GSM!

Coded Composite Transport Channels

A multiplex of transport channels in the physical layer


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RRM : Downlink Power Control

Inner loop : TPC command bits sent by UE SIR est > SIR target => TPC command 0

SIR est < SIR target => TPC command 1

Downlink outer loop function in UE or RNC : sets and updates the SIR

target, based on quality measurements.

RNC

Node B

UE

TPC

SIR

target Inner loop

ualit Measurements


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RRM : Uplink Power Control

Inner loop : TPC command bits sent by NodeB SIR est > SIR target => TPC command 0

SIR est < SIR target => TPC command 1

Uplink outer loop function in RNC : sets and updates the SIR target, based

on quality measurements received from the NodeB(s)

RNC

Node B

UE

TPC

SIR

target

Inner loop

Qualit Measurements


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UTRAN Network Elements

NN Node B


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Functions:Network Interface

Call Processing

Signal processing

Frequency up/down

conversion

Functions:

Tx amplification

Coupling


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NODE B

NN has two types of Node B OTSR (Omni Tx sector Rx)

Low Cost and limited capacity

STSR (sector Tx sector Rx)

High capacity

The functions ofNode B are:

Air interface Transmission / Reception Modulation / Demodulation

CDMA Physical Channel coding

Micro Diversity

Error Handing

Closed loop power control

OTSR - Omni Transmit Sector Receive


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Transmit path :

1 cell, 3 antennas Receive path :continuous

softer handover

1Watt

1Watt1Watt

TRM

DDM

Tx Splitter

PA

DDM DDM

DDM Dual Duplexer module (for Main and Diversity)Tx and Rx out of band filtering

Isolation b/w Tx and Rx frequency bands

VSWR alarm monitoring capability

TMA DC supplying

STSR - Sectorial Transmit Sector Receive


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Transmit path :3 cells, 3 antennas

Evolution from OTSR to STSR : no coverage re-engineeringEvolution from OTSR to STSR : no coverage re-engineering

TRM

DDM

PA

DDM DDM

PAPA

NN RNC


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NN RNC

- RANAP - Iu FP

- RNSAP - Iur FP

- NBAP

- Qaal2.CS1

Control Plane User Plane

Network Interface Protocol termination

Radio Resource ManagementRRC terminationRRM strategy

QoS management

UTRAN OA&M

RNC OA&M

Network Interface Protocol termination

- Iub FPs Combining / Splitting

Compression

Ciphering

Radio ProtocolsRLC

MAC

ATM QoS mgt

Functions:Physical connectivity

with other UMTS nodes

Radi protocol termination

UTRAN PS functions

Functions:Control plane Protocol

termination

RRM

iRNC OA&M

Node B logical OA&M

Call Processing

RNC Applicative Functions

RNC


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RNC

RRC

Management of radio resources (establishment, release and termination)

Management of RRC connection of RRC connection between the UE and

network (establishment, release)

RRM

The RRM is the most critical resource in wireless systems.

It is in charge of allocating and managing radio resources in the most

effective way.

QoS

High QoS (ensuring subscribers satisfaction)

High spectrum efficiency (maximum operator revenue)

Easy (re)configuration (lowering operational costs)


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Link Budget Overview

Link Budget


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Link Budget

The object of the link budget design is to calculate maximum cell size under

given criteria:

Type of service (data type and speed) Type of environment (terrain, building penetration)

Behavior and type of mobile (speed, max power level)

System configuration (Node B antennas, Node B power, cable losses,

handover gain) Required coverage probability

Financial and economical factors (use of more expensive and better

quality equipment or not the cheapest installation method) and to match

all of those to the required system coverage, capacity and quality needswith each area and service.

Link Budget


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g

Eb/NoProcessing Gain

PA Power

diversity (Tx, Rx)

...

BTSNode B

Eb/NoProcessing Gain

PA Power

diversity (Tx, Rx)

...

MSMS

ServiceService

Cable losses

antennas

site configuration(bi, tri-sectorial)

...

SiteSite

margins

propagationmargins

propagation

Cell Range Traffic offered per cellCell Range Traffic offered per cell


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LB @ X% loadDesign assumptions

Comparison

Decision

Final number of sites

Cell size Cell capacity

# sites for coverage # sites for traffic

adjustload


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All of the design assumptions are correlated

Services

Coverage types

Service areas of coverage

Capacities

Quality of coverage

Radio network design results are highly dependant of the designassumptions :

Any change of one of the assumptions implies to redo the design work !

O2 Link Budget (2000)


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Maximum path loss for UMTS planning On-Street In-Car In-Build (Dense urban) In-Build (suburban) In-Build (rural) In-train (open line) In-train (cutting)

Units Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze

Soft Handoff Gain dB 4 4 4 3 3 3 4 4 4 4 4 4 3 3 3 3 3 3 3 3 3

Penetration Loss dB 0 0 0 2.3 2.3 2.3 18 18 18 5 5 5 5 5 5 0 0 0 0 0 0

Overall standard dev for measurements dB 5.68 5.68 5.68 7.84 7.84 7.84 5.68 5.68 5.68 8.26 8.26 8.26 8.26 8.26 8.26 10.81 10.81 10.81 11.50 11.50 11.50

Fade Margin dB 9.38 7.27 5.91 12.93 10.03 8.15 9.38 7.27 5.91 13.64 10.58 8.59 13.64 10.58 8.59 17.84 13.84 11.25 18.98 14.72 11.96

Maximum path loss dB 145 148 149 139 142 143 127 130 131 136 139 141 135 138 140 136 140 143 135 139 142

Link Budget Units Uplink

Service 64LCD

Environment Vehic. A

Service Rate (Average throughput for packet) 64000BS antenna height (m) 25

MS antenna height (m) 1.5

Frequency (MHz) 2000

Power limit in the DL (if 0, there is no limit) NA

Transmitter

UL/DL load factor (from pole capacity) 60%

% Power of the BS used for common ch NA

% Power used for soft handoff NA

Maximum Total Tx power dBm 21Maximum Tx power per traffic channel dBm 21

Power used in the Cell (DL) NA

Body Loss / Cable Loss dB 1

Tx antenna gain dBi 0

EIRP dBm 20.00

Receiver

Rx antenna gain dBi 16

Body Loss / Cable Loss dB 3Receiver Noise Figure dB 3.3

Thermal Noise Density dBm/Hz -174

Noise rise due to Interference dB 3.98

No+Ior+Ioc dBm/Hz -166.72

Information Rate dBHz 48.06

Target Eb/(No+Io) dB 3.8

MHA Gain dB 3

Receiver Sensivity dBm -117.86

Cell size On-Street In-Car In-Build (urban) In-Build (suburban) In-Build (rural) In-train (open line) In-train (cutting)

Units Gold Si lver Bronze Gold Silver Bronze Gold Si lver Bronze Gold Silver Bronze Gold Silver Bronze Gold Silver Bronze Gold Si lver Bronze

Cell radius Km 2.24 2.59 2.85 2.89 3.54 4.04 0.42 0.48 0.53 1.17 1.45 1.66 1.44 1.79 2.05 2.40 3.18 3.82 2.22 2.99 3.63

Cell area Km2 9.76 13.10 15.86 16.25 24.40 31.76 0.34 0.45 0.55 2 .67 4.09 5.40 4.06 6.23 8.23 11.28 19.76 28.42 9.62 17.46 25.71


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Coverage vs Interference Control

Link Budget


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Cell range & cell capacity are limited by the same parameters:

Interference in uplink

Power in downlink

Cell breathing phenomenon

Coverage Vs Interference


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Co e age s e e e ce

WHAT IS THE PILOT POLLUTION ?

Area where the SIR (Signal interference ratio) is too low and below the expected

value (Ec/Io >= -12 dB), there is too much interference => the mobile cannot

understand the pilot channel

HOW TO REDUCE THE PILOT POLLUTION PROBLEM ?

Maximise the signal inside the best server

Minimise the energy overshoot to the neighbor cells with some RF consideration

(tilt, azimuth,)

Good Design Bad Design

333 1

11222

111

222

3334 5

6

Coverage vs interference


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RF design optimisation for capacity

Multi-Carriers solution

Adding new sites

RF design optimisation for coverage

When the sites are placed, it is necessary to verify that the both UL&DL

quality of coverage are reached for each service.

The coverage optimisation is performed on

Site position

Antenna tilt and azimuth

Adding new sites if necessary

Continuous process

Coverage vs Interference


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Coverage vs Interference

UMTS network radio design is highly dependant of the designsassumptions

Optimum network radio design requires accurate design assumptions in

terms of services, coverage, capacity, and quality of service

UMTS network radio dimensioning is a very complex task, the multi-

service capacity and coverage should be treated together, since they

share the single and the same radio resource.


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BREAK


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Cell Selection and Reselection

Call Setup Process

and

Call Establishment Steps


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UE Node B RNC


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UE Node B RNC

CCCH / RACH RRC Connection Request

Radio Link Setup Request

Radio Link Setup Response

DL Synchronisation

UL Synchronisation

CCCH / FACH RRC Connection Setup

DCCH RRC Connection Setup Complete

RRC Connection Establishment

Cell selection and Reselection


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Network Selection Mobile in idle mode acquires the best received UMTS cell and identifies its

scrambling code

Mobile in idle mode selects the PLMN

Cell Selection Mobile in idle mode selects the cell to camp on according basic criteria

Cell Reselection

Mobile in idle mode selects a cell according to parameters broadcasted on the

current cell

Location Registration

The mobile in idle mode informs the network about a change of location area

Handover

Mobile in active mode in one cell is handed over to another cell

Initial Cell Search


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Initial Cell Search

The initial Cell Search is carried out in three steps:

Step 1: Slot synchronisation - using the primarysynchronisation channel.

Step 2: Frame synchronisation and code-group identification-

using the secondary synchronisation channel.

Step 3: Scrambling-code identification-identified through symbol-

by-symbol correlation over the primary CCPCH with all

the scrambling codes within the code group.

Mobile Behaviour


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Mobile is switched ON

Does the UE have in memory

the frequency used previously ?

Mobile is searching for P-SCH on this frequency

YesNo

Mobile is scanning the band fromthe lower UMTS Frequency

P-SCH Found No P-SCH

Scanning next

frequency

P-SCH Found

No P-SCH

Cell Selection Cell Selection

P-SCH1 P-SCH2


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Slot Synchronization

P-SCH3

P-SCH1S-SCH1 P-CCPCH P-CCPCH

P-SCH2S-SCH2 P-CCPCH P-CCPCH

P-SCH3S-SCH3 P-CCPCH P-CCPCHP-CCPCH

1 Slot = 667s

UE synchronizes on the strongest correlation peak

Frame Synchronization P-SCH


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..

2560 chips

acp

Slot # ?

P-SCH acp

Slot #?

16 11S-SCH

acp

Slot #?

2Group 4

Slot 12,13,14

s lo t n u m b e r S c r a m b l i n g

C o d e G r o u p # 0 # 1 # 2 # 3 # 4 # 5 # 6 # 7 # 8 # 9 # 1 0 # 1 1 # 1 2 # 1 3 # 1 4

G r o u p 0 1 1 2 8 9 1 0 1 5 8 1 0 1 6 2 7 1 5 7 1 6

G r o u p 1 1 1 5 1 6 7 3 1 4 1 6 3 1 0 5 1 2 1 4 1 2 1 0

G r o u p 2 1 2 1 1 5 5 5 1 2 1 6 6 1 1 2 1 6 1 1 1 5 1 2

G r o u p 3 1 2 3 1 8 6 5 2 5 8 4 4 6 3 7

G r o u p 4 1 2 1 6 6 6 1 1 1 5 5 1 2 1 1 5 1 2 1 6 1 1 2

G r o u p 6 1 9 1 0 1 3 1 0 1 1 1 5 1 5 9 1 6 1 2 1 4 1 3 1 6 1 4 1 1

G r o u p 6 2 9 1 1 1 2 1 5 1 2 9 1 3 1 3 1 1 1 4 1 0 1 6 1 5 1 4 1 6

G r o u p 6 3 9 1 2 1 0 1 5 1 3 1 4 9 1 4 1 5 1 1 1 1 1 3 1 2 1 6 1 0

256 chips

S-SCH

512 Primary Scrambling Codes divided into 64 groups512 Primary Scrambling Codes divided into 64 groups

Scrambling Code Identification


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P-SCH

S-SCH

P-CPICH

P-CPICH: Predefined sequence (20 bits) spread with Cch,256,0 scrambled with the primary SC

x OVSF

Cch,256,0x SC #i

Symbol by Symbol

Correlation ?

Primary DL Scrambling CodeKnown (best correlation peak)

For i = 1 to 8

YesNo

Mapping between group and Scramblingcodes defined in TS 25.331


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Cell InformationP-SCH: Coverage indication, Slot Synchronization

S-SCH: Frame Synchronization, Group identificationP-CPICH: Scrambling Code Identification

P-CCPCH: System Information Broadcast

Logical Channel

BCCH

Transport Channel

BCH

Physical Channel

P-CCPCH

OVSF Cch,256,1Primary Scrambling Code

Transmitted during 9/10th slot

Bit Rate: 12.3 kbps RLC Mode: transparent

Mac-B: transparent

Cell Selection Procedure


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Definitions:

Acceptable Cell:

Cell on which UE can obtain limited services (emergency calls)

Suitable Cell:

Cell on which the UE can obtain a normal service

UE States for cell Selection / Reselection: Camped on any cell:

UE monitors System Information but has chosen a cell irrespective of PLMN identity

Camped on a cell:

UE monitors System Information and paging information

Cell Selection Parameters


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C3

C2

C2

Class

3333Int [-50..33]

(dBm)

UlUsPowerConfmaxAllowedUlTxPower

-115-45Int [-115..-25]

Step = 2 (dBm)

CellSelectionInfoqRxLevMin

-16-10Int [-24..0]

(dB)

CellSelectionInfoqQualMin

Recommended ValueDefault ValueRangeObjectParameter

214

243

272

331

Maximum Output Power (dBm)Power Class

P_Max = maximum UE output power (dBm) according to its class

Cell Reselection Procedure


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?2G

3GFreq. 2

3GFreq. 1

General Description:

On a cell, the UE listens to system information andperforms radio measurements

The network controls what the UE shall measure andsends the system information data concerning theneighboring cell

The UE then uses an algorithm to select a better cell

The Inter-Frequency algorithm uses a set of broadcast

parameters : a criteria for searching Inter-frequency cells and

performing measurements

a criteria S to assess whether the cells are eligible

a criteria R for ranking eligible cells and determiningthe best one

3G can be favoured compared to 2G by playing on engineering parameters

Cell Reselection Procedure


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Squal

SintraSearch

SinterSearch

SinterRATMeasurement onsame frequency Measurement on

other frequencies Measurement on

other RAT

If Squal = CPICH_Ec/No qQualMin < ThresholdAssociated measurements are performed

Thresholds are broadcasted in SIB 11

In UMTS02, 2 types of measurements are done: Intra frequency and inter RAT

Thr

eseholdsgivenasexample


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Cell Reselection Parameters

C2

Static

C0

C0

C2

C2

Class

631Int [0..31] (s)CellSelectionInfoReselection

TBD0Int [-50..50] (dB)UMTSFDDNeighbouringOffset2snN.A.CPICH_EcNoCPICH_EcNo or

CPICH_RSCP

qualMeas

TBD0Int [-50..50] (dB)GSMCellOffset1sn

64Int [0..40] (dB)

Step = 2

CellSelectionInfoHyst2

410Int [0..40] (dBm)Step = 2

CellSelectionInfoHyst1

Recommended ValueDefault ValueRangeObjectParameter

Mobility in Idle Mode Strategy


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Target: Staying in UMTS as much as possibleUMTS cells

GSM cells

Squal

No Intra frequency measurements

Intra frequency measurements performed

No Inter frequency measurements

Inter frequency measurements performed

No Inter System measurements

Inter system measurements performed

Sintrasearch

Sintersearch

SsearchRAT

Measurement Trigger:

Sintrasearch > SsearchRAT

For the serving cell

Rs = Qmeas,s + qHystFor the neighboring cells

Rn = Qmeas,n - qOffset

Cell Ranking Criteria

Qoffset (3G cell) < Qoffset (2G cells)Qhyst set to a high value

qRxLevMin setting not too low to avoid too many 2G eligible cells

Cell Access Restrictions


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C0notReservednotReservedReserved

notReserved

FDDCellellRservationExtension

C0TBDBarredS160barredS10, barredS20, barredS40,barredS80, barredS160, barredS320,

barredS640, barredS1280

FDDCellBarred

C0AllowedAllowedAllowed

notAllowed

FDDCellntraFreqCellReselectInd

ClassRecommended ValueDefault ValueRangeObjectParameter

C0

C0

C0

notReservednotReservedReserved

notReserved

FDDCellellReservedForOperatorUse

notBarrednotBarredBarred

notBarred

FDDCellarredOrNot

N.A.N.A.List 0..15

Barred/notbarred

FDDCellccessClassBared

The following parameters allow to restrict access to some cells. They prevent to send the

initial access message, but there is no impact on cell selection/reselection


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Measurements

Measurements

Th diff t t f i i t f t


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The different types of air interface measurements are:

Intra-frequency measurements: measurements on downlink physical channels at the

same frequency as the active set. A measurement object corresponds to one cell.

Inter-frequency measurements: measurements on downlink physical channels at

frequencies that differ from the frequency of the active set. A measurement object

corresponds to one cell.

Inter-RAT measurements: measurements on downlink physical channels belonging to

anotherradio access technology than UTRAN, e.g. GSM. A measurement object

corresponds to one cell.

Measurements


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Traffic volume measurements: measurements on uplink traffic volume. A

measurement object corresponds to one cell.

Quality measurements: Measurements of downlink quality parameters, e.g.

downlink transport block error rate. A measurement object corresponds to one

transport channel in case of BLER. A measurement object corresponds to one

timeslot in case of SIR (TDD only).

UE-internal measurements: Measurements of UE transmission power and UE

received signal level.

UE positioning measurements: Measurements of UE position.

The UE supports a number of measurements running in parallel. The UE also

supports that each measurement is controlled and reported independently of

every other measurement.

Handover (Handoff)

There are following categories of handover (also referred to as handoff):


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Hard handovermeans that all the old radio links in the UE are removed beforethe new radio links are established. Hard handover can be seamless or non-

seamless. Seamless hard handover means that the handover is not perceptible to

the user. In practice a handover that requires a change of the carrier frequency(inter-frequency handover) is always performed as hard handover.

Soft handovermeans that the radio links are added and removed in a way that

the UE always keeps at least one radio link to the UTRAN. Soft handover isperformed by means of macro diversity, which refers to the condition that several

radio links are active at the same time.

Softer handoveris a special case of soft handover where the radio links that areadded and removed belong to the same Node B (i.e. the site of co-located base

stations from which several sector-cells are served.

Handover (Handoff)

The most obvious cause for performing a handover is that due to its


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The most obvious cause for performing a handover is that due to its

movement a user can be served in another cell more efficiently (like lesspower emission, less interference). It may however also be performed for

other reasons such as system load control.

Active Set is defined as the set of Node-Bs the UE is simultaneouslyconnected to (i.e., the UTRA cells currently assigning a downlink DPCH to

the UE constitute the active set).

Cells, which are not included in the active set, but are included in the

CELL_INFO_LIST belong to the Monitored Set.

Cells detected by the UE, which are neither in the CELL_INFO_LIST nor inthe active set belong to the Detected Set. Reporting of measurements of the

detected set is only applicable to intra-frequency measurements made by

UEs in CELL_DCH state.

SOFT HO


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It applies to dedicated physical channeland is only applicable when a DTCH isallocated. It is a case when more than onebase station (Node B) has a

communication link established with theUE. The UE is connected to a set of cellsknown as the active set.

The maximum active set size at the RNC is determined by theparameterMaxAciveSetSize

Intra Node B

Inter Node B

Intra RNC

Inter RNC

Soft HO diagram

SOFTER HO


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It is a case where the cells

communicating with the UE are part of

the same base station (Node B).

Softer HO diagram

SOFT HO (Intra RNC)


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Intra RNC soft HO

The cells involved in the process

belong to different Node Bs that areconnected to the same Serving RNC

(SRNC).

Soft HO (Intra RNC)


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Intra RNC soft HO message flow

Soft HO (Inter RNC)

This is when the Drift and Serving RNC


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comes into play.

The Serving RNC is in charge of the

RNC connection to the mobile (UE)

The drift RNC controls the Node B that

does not belong to the Serving RNC

and for which a radio link needs to be

established with the mobile.

An Iur, link between the SRNC and

DRNC is required to perform the inter

RNC soft HO. If this link is not present,

a HO will take place.

From the SRNC to the UTRAN

transport perspective the, the DRNC

acts as a router.

Inter RNC soft HO

SOFT HO (Inter RNC)


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Inter RNC soft HO message flow

SOFT/SOFTER HO ALGORITHM


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The purpose of the Soft HO algorithm (also referred to

as active set update algorithm) is to ensure that the

strongest cells in the UE environment will be part of itsactive set i.e supporting the call and carrying the user

information.

PRIMARY CELL ELECTION ALGORITHM(MONITORED SET UPDATE)

The primary cell election algorithm


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The primary cell election algorithmapplies to soft HO. It is used formonitored set determination and a pointerto mobility parameter.

The Monitored Set should be updatedeach time the primary cell of active setchanges. A measurement controlmessage is sent (with measurementcommend set to modify) is sent to the UEin order to update the monitored set. The

message contains the cell to add/removefrom the monitored and should follow theACIVE SET UPDATE message.

The primary cell algorithm is called from

SHO algorithm; therefore it is performedeach time a MEASUREMENT REPORT isreceived by the SRNC.

Measurement control used for monitored set update

CS - UE Originating - Call setup


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CS UE Terminating - Call setup


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CS UE Originating - Call release


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CS Network Originating - Call release


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PS UE Originating PDP Context Activation


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PS UE Originating PDP Context DeActivation


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Inter-System Handover


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The RANAP signalling used on the UMTS side is the relocation signalling. It is used forCS scenarios but also for PS scenarios where the relocation can be initiated by thenetwork. The signalling on the GSM side is the BSSMAP handover signalling. Thesignalling on the GPRS side is the GMM routing area update signalling.

Conversions

The 3G MSC needs to convert RANAP to BSSMAP so that it can support

handovers from UMTS to GSM. For GSM to UMTS handovers it also has toconvert BSSMAP messages to RANAP messages.

The UE-CN signalling is very similar in 2G or 3G. No conversion is needed to

accommodate the differencies.

Handovers for CS-domain: key interfaces

UMTS Call

Server

UMTS Call

Server


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UE

GSM

BSS

RANAP,

BSSMAP

Signalling

MEGACO

UTRAN

PSTN

G/W

Wireless

Gateway

I

u

ISUP2G-MSC

UE

3G to 2G handover (CS domain)

UE

GSM

BSS

2G-MSC

UE

UTRAN

PSTN

G/W

Wireless

Gateway

I

u

ISU

P

ISUP

MEGACO

RANAP,

BSSMAP

Signalling

MEGACO

2G to 3G handover (CS domain)

ISUP

MEGACO

Call is

anchored

at Wireless

Gateway

Present inUMTS 2d

release only

3G to 2G Handover (UE connected to CS domain moves to GSM)

RN: Relocation Required

Classmark 2 Classmark 3 BM: Handover request (CM2

UE UTRA

N

2G-MSC BSS

MAP: Prepare Handover

Request (CM2 CM3 old

UMTS

Call Server

Wireless

Gateway/SGS

N

PSTN

Gateway

Hard handover from UMTS

to GSM

Anchor retained in UMTS

t k UMTS ll

BSSMAP

message

encapsulatedOnly included

when target is

GSM

RANAP to BSSMAP

Conversion


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RN: Relocation command

RN: Iu release command

Classmark 2, Classmark 3Source RNC to target

RNC transparent container

BM: Handover request (CM2,CM3, old BSS to new BSS)

PS Domain Routing Area Update if required

Key to protocol name abbreviations:

RRC - Radio Resource Control

RN - RANAP

BM - BSSMAP

Request (CM2, CM3, oldBSS to new BSS info)


Response

BM: Handover request Ack

RN: Iu release complete

RRC: Handover command

BM: Handover detect

BM: Handover complete

RRC: Handover Complete

MAP: Send End Signal

Request

The UMTS Call Server converts

RANAP to BSSMAP and sends

BSSAP messages to the 2G-MSC,

with BSSMAP messagesencapsulated.

This conversion includes conversion

from transparent container used in

UMTS to the old BSS to new BSS IE

in BSSMAP.

The UMTS Call Server uses 2G

ciphering keys for relocation to 2Gand sends the ciphering information

via MAP.

Q2630.1 REL

Q2630.1 RLC

ISUP: IAM

ISUP: ACM

ISUP: ANM

network - UMTS call

control and services

throughout call

Backwards compatible with

GSM network elements

Also possible when GSMcells are connected to the

UMTS core networkGateway and

Backbone control

signalling

Q.AAL2

signalling

Contains GSM

information for

BSS (08.08)

GSM

This is MEGACO

signalling in UMTS

release 2 with the

PSTN GatewayThis is BSSMAP

signalling in UMTS

release 1; no

PSTN Gateway

2G to 3G Handover (UE connected to GSM moves to UMTS)

BM: Handover

Required

Old BSS to new

RN: Relocation request (Source RNC to target RNC transparent container)

UE BSS 2G-MSCWireless

Gateway/SGS

N

UMTS

Call ServerUTRAN


Request (BSS-APDU)

PSTN

Gateway

Contains UE

capability info

Contains

all theBSSMAP

message

BSSMAP to

RANAP conversion

Additions to


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BM: Handover

command

BM: Clearcommand

Old BSS to newBSS info

Source RNC to

target RNC

container

PS Domain Routing Area Update

Request (BSS-APDU)


Response

RN: Relocation request Ack

BM: Clear complete

RRC:

Handover

command

RN: Relocation detect

RN: Relocation complete

RRC: Handover Complete

MAP: Send End Signal

Request

The UMTS Call Server

converts BSSMAP messages

encapsulated in BSSAP to

equivalent RANAP messages

for the Iu interface.

The ciphering keys received

from the 2G-MSC are

converted into 3G ciphering

keys by the UMTS call server.

The keys are then applied to

the UTRAN.

Q.2630.1 ERQ

Q.2630.1 ECFISUP: IAM

ISUP:

ACM

ISUP:

ANM

Anchor retained in GSM

network - GSM call control

and services throughout

call


GSM network elements

Also possible when GSM

cells are connected to the

UMTS core network

Q.AAL2

signalling

Gateway

and

Backbone

control

signalling

ISUP:

ACM

Additions to

BSSMAP

messages for

handover to

UTRAN is

under way

Handovers for PS-domain: key interfaces


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UE

GSM

BSSUTRAN

3G-

SGSNGGSN

Iu 2G-SGSN

UE

3G to 2G handover (PS domain)

UE

GSM

BSS

2G-SGSN

UE

UTRAN

GGSN

3G-SGSN

I

u

GTP

2G to 3G handover (PS domain)

GT

P

G

n

G

n

GT

P GT

P

3G to 2G Handover (UE connected to PS domain moves to GPRS)UE UTRAN

The trigger for the handover can be

the UE. Or, the serving RNC can

trigger the handover to GPRS based

on UE measurements. In any case the

UE stops sending UL to 2G

2G-SGSN BSS

GTP: SGSN Context Request

3G-SGSN

GMM: Routing Area Update Request (MS radio access capabilities)

GGS

N

3G-SGSN

HLR

RRC: Handover command

UTRAN adds

CGI (RAC,


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U s ops se d g U o G

Key to protocol name abbreviations:

GMM - GPRS Mobility Management

GTP - GPRS Tunnelling protocol

RN - RANAP

GTP: SGSN Context Request

GTP: SGSN Context Response

(MS network capabilities)

RN: Iu release complete

RN: SRNS Context Request

RN: SRNS Context Response

GTP: SGSN Context Ack

N-PDU Data Transfer

N-PDU Data Transfer

GTP: Update PDP Context Request

GTP: Update PDP Context Response

GMM: Routing Area Update Accept

GMM: Routing Area Update Complete

handover from UMTS to

GPRS


GPRS network elements Also possible when GSM

cells are connected to the

UMTS core network

The 3G-SGSN does the

QoS mapping. By moving

to 2G, the UMTS QoSservices are lost

Data forwarding

The source RNC instructs the CN about

DL/UL GTP/PDCP PDU sequence

numbers for lossless relocation

Contains MS

GPRS/UMTS

cipheringcapabilities

RN: SRNS data forward command

3G SGSNstarts a timer

Timer expiry

MAP: Update GPRS location

RN: Iu release command

MAP: Cancel location

MAP: Cancel location ackMAP: Insert subscriber data

MAP: Insert subscriber data ack

CGI (RAC,LAC)

TLLI and P-TMSI usage in GMM/GTP messages to be checked

UTRAN stops

sending DL to

UE

Security functions

The 3G-SGSN converts the 3G

ciphering keys into 2G keys (see

33.102). These keys are sent in the

GTP:SGSN context response

message.

When does

the packet

forwarding

stop?

Compressed Mode

During inter-frequency handover the UEs must be given time to make the


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During inter-frequency handover the UE s must be given time to make thenecessary measurements on the different WCDMA carrier frequency. 1 to 7

slots per frame can be allocated for the UE to perform this intra frequency

(hard handover).

Why is compressed mode needed?

In UTRAN FDD, transmission/reception by the mobile is continuous : no idle periods are

available for monitoring other frequencies if the UE has only a single receiver

How is it done? Transmission gaps are created in the radio frame in DL and/or UL to allow the UE to

switch to another frequency, perform measurements on another carrier (FDD, TDD or

GSM) and switch back

Transmission gaps are positioned in one radio frame or at the boundary of 2 radio framesin regular intervals referred to as a transmission gap pattern sequencetransmission gap pattern sequence

no more than 7 slots are used in any one radio frame to create the transmission gap.

Compressed Mode

How is it done?

Two approaches can be taken in creating the transmission gaps of the


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Two approaches can be taken in creating the transmission gaps of the

transmission gap pattern sequence

Modifiy the physical layer parameters (by puncturing or spreading factor reduction) to allow all

information bits to be transmitted.

Restrict the bit rate (by higher layer scheduling) to match the fewer available transmission slots in acompressed radio frame.

In both approaches, the goal is to not loose transmission frames

Compressed Mode

Who controls it?


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Who controls it?

Compressed mode is under the control of the UTRAN

Compressed mode is configured by the RNC per UE in the form of

transmission gap pattern sequencestransmission gap pattern sequences

given to the UE via RRC signalling

given to the node B via NBAP signalling

a transmission gap pattern sequence is associated with a specific measurement purpose:

FDD measurements,

TDD measurements,

GSM initial BSIC identification, GSM BSIC reconfirmation,

GSM RSSI measurement


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OPTIMISATION

Optimisation - Optimisation Process

Route definition

Data Collection


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ServerData AnalysisSignal PropagationAnalysis

FTP

Drive Team ADrive Team B

Drive Team C

FTP

Aspirational Goals for Optimisation

Three type of RF Optimisation Targets


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CPICH_RSCP:

Optimisation will aim to provide Dense Urban or Suburban CPICH signal

levels according to the criterion presented in next slide.

CPICH_Ec/Io:

Optimisation will aim to provide a CPICH_Ec/Io >= -11 dB in 100% of the

bins where the CPICH_RSCP target is met.

Optimisation will aim to provide a CPICH_Ec/Io >= -9 dB in 95% of the bins

where the CPICH_RSCP target is met.

For the areas where the target CPICH_RSCP can not be met, optimisation

will aim to maximise the number of bins where CPICH_Ec/Io >= -9 dB.

Number of Cells within a 7 dB window from the best server: Optimisation will aim to obtain at maximum 4 cells (including best server)within the window for 95% of the bins where the CPICH_RSCP target is met.

Optimisation will aim to maximise the number of bins where the number of

cells within the window is at maximum 4 (including best server) for areas

where the CPICH_RSCP target is not met.

RF Build Audit


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Why do you need to carry out RF Build Audit ?

To ensure accurate and correct planning tool database

To verify site installation/build is consistent with design

To ensure that as-built drawing is correct and up-to-date

To limit unnecessary time wasting during optimisation

To ensure that optimisation changes recommendation are effective.

Cluster Definition

Cluster Size

Cluster is a group of sites.

It could be defined subject to availability of sites (small cluster e.g 5 sites)


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It could be defined subject to time constraints (large cluster)

Cluster size should be limited to 20-30 sites to allow faster optimisation.

Cluster drive test survey should not exceed 1.5 to 2 days.

Cluster Definition rules

A site can only belong to one cluster

The cluster boundary should be a polygon that minimises the boundaries with neighbouring

clusters. If possible, cluster borders shall be defined along natural barriers for the RF propagation

The urban centres shall be kept as close as possible the centre of a cluster.

Key roads and rail routes should be avoided as cluster boundaries.

Identified boomer sites, high sites or sites with poor RF quality shall, whenever possible, be

located close to the centre of the cluster.

Open areas such as stretches of water or sides of valleys where propagation would be

enhanced cannot be considered in isolation and a cluster shall include the whole open area.

Optimisation Route Definition Optimisation Route definition rules

Drive test to be done in 1 day (small cluster) and 2 days max. (large cluster).

All t i it i th l t h ld b d b th d i t


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All sectors in every site in the cluster should be covered by the drive route.

Drive routes shall be defined to cross the edges of 3G coverage (i.e. when the mobile hands

over to 2G), to ensure that the 3G edge of coverage is crossed whilst drive testing.

Routes should be defined around key business centres, shopping centres, tourist attractions

and railway stations.

Route must include major roads: Motorways, A roads, B roads and other important road.

The routes should be laid out to gain a clear footprint of each cell (that can be achieved within

1 day), such that close-in problems such as low transmit power as well as far-off problems

such as spill-over can be observed.

Acceptance Route Definition Acceptance Route Definition Rules

The Drive Test Routes for Cluster Acceptance shall be a sub-set of the optimisation route.

Drive test to be done in 1 day (small cluster) and 2 days max. (large cluster).


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All sectors in every site in the cluster should be covered by the drive route.

Drive routes shall be defined to cross the edges of 3G coverage (i.e. when the mobile hands

over to 2G), to ensure that the 3G edge of coverage is crossed whilst drive testing.

Routes should be defined around key business centres, shopping centres, tourist attractions and

railway stations.

Route must include major roads: Motorways, A roads, B roads and other important road.

The routes should be laid out to gain a clear footprint of each cell (that can be achieved within 1

or 2 days), such that close-in problems such as low transmit power as well as far-off problems

such as spill-over can be observed.

Inter Cluster Optimisation Definition

Objective:

The objective of network optimisation is to

optimise all clusters covering an entire


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region.

Process:

refer to Cluster Optimisation guidelines.

Focused on the areas affected by cells with

cross-cluster effects

Optimisation Drive Test Routes will cover all

cells belonging to cluster B and buffer areasin clusters A and C.

The optimisation of 1st and 2nd tier sectors

of clusters A and C pointing to cluster B will

be done at this stage.

Cell Shakedown/Site verification

Objective

The objective of the cell shakedown is to ensure that sites are operating properly.

Cell Shakedown is the last check after integration and prior to optimisation to detect any residual


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issues affecting effective site operation.

Sector

Carrier

Code

Power

Sector

Carrier

Code

Power

Sector

Carrier

Code

Power

(Pre-requisites)Antenna sweep tests must be

successfully completed

Integration tests must be passedand accepted

RNS, NSS and WG datafill

parameters must be verified in

details.

Cleared spectrum

Cell Shakedown

Purpose


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Purpose

To test Call Setup (Voice and FTP) in each cell

To test Handoffs (Soft and Softer) between Cells

Verify antenna orientation

Primary Pilot Ec/Io

Scrambling Code for each cell

UE transmit power

Path Balance

Method

By driving clockwise and anticlockwise within a designated route around the

the base station (about 30% of the site coverage area).

Optimisation - Atoll Neighbour List generation

Effective neighbor list

planning, save unnecessarydrive test


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AtollMapper

Neighbour List Generated

Neighbour List Generation

is base on :-

Atoll coverageprediction to generate a

baseline neighbor list

automatically

Mapper neighbor

verification wereconducted base on local

knowledge and terrain

profile analysis

NOTE: This is an example as o2 is using Odyssey planning tool.

Neighbouring Plan Optimisation (2G Neighbours)

Thresholds for analysis of outdoor measurements


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Thresholds for analysis of outdoor measurements

1. Outdoor areas where the 3G coverage is insufficient

CPICH_RSCP


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p p gg p

regions the 2G measurements done in active mode will be analyzed. The top 2G cell will be

considered as a neighbour as long it provides enough signal strength and dominance.

2. Areas where the Ec/Io is lower than the target for 3G/2G handover

These regions will be identified using the 3G EcIo measurements considering the

cpichEcNoThresholdused to trigger the compress mode and the hard handover to 2G. Within these

regions the 2G measurements done in active mode will be analyzed. The top 2G cell will be

considered as a neighbour as long it provides enough signal strength and dominance.

3. Indoor

These regions will be identified using the 3G RSCP outdoor measurements considering the

cpichRscpThresholdused to trigger the compress mode and the hard handover to 2G corrected with

the deep indoor penetration margin. Within these regions the 2G measurements done in active mode

will be analyzed. The top 2G cells will be considered as a neighbour as long they provide enough

signal strength and dominance

Note: Due to current software limitations only 16 2G neighbours can be define per 3G cell. Whenever this number

proves to be insufficient, the cluster exit reports will include a list of the necessary but undefined 2G neighbours


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Optimisation

Scanner data vs UE data analysis

Antenna Configuration Change

Identifying area of concern due to poorEc/Io, Active set, RSCP

Recommending optimisation changes

Neighbour list definition

Analysing Problem Calls (Voice, Data and

Video).

Difference between Scanner data & UE

Data CollectionDifference in data collection


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Scanner

Primary Common Pilot Channel (P-CPICH)

scrambling code measurements

Continuous Wave (CW) measurements

Spectrum analysis

Synchronization Channel (SCH) code word

measurements

UE Data/Voice/Video Calls

Layer 3 messages logging

Layer 2 messages logging (Transportchannel)

RRC State logging

UE Transmit Power SIR

Serving Cell / Active Set / Monitored Set

Events

GSM neighbor measurements

Antenna

Cable

Sampling

Solution: Perform a calibration drive.

Scanner and UE Data Post-Processing-

Export Logfile Export LogfileL fil t l fil


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Log file => export logfile

Scanner and UE Data Post-Processing-Report

GeneratorR t G t


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Report Generator

Log file => Report Generator


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Why use it widely for WCDMA?


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A cell broadcasts channels with

different frequencies and or

slots.

1. The neighbouring cells utilisedifferent group of frequencies,

which helps mitigate inter-cell

interference. This is achieved by

the frequency planning process.

Both of the options are not

available in WCDMA.

Solution:Techniques such as down-tilt and

azimuth changes, which direct RF

energy from undesired areas to

desired areas, are likely to becrucial in controlling pilot pollution

and maximising capacity.

GSM WCDMA

Antenna Configuration Change (example)


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View from Site 869 along approximate sector 2 azimuth


(example), Cont.


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RSCP plot for sector 2 of site 869 (SC 104) with 6EDT

neighbor relations


(example), Cont.


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RSCP plot for cell sector 2 of site 869 (SC 104) with 6EDT

and 4MDT

TEMS Scanner WCDMA and UE (applications)

Neighbor list optimization

B di S i C ll / A i S / M i d S


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Best servers according to Serving Cell / Active Set / Monitored Set

Increase scanning capability, e.g. scan on different frequencies

Missing neighbor detection (application)

Optimization of neighbor relations

Turn interferer into useful link, (Include interfering cell in neighbor list

Interferer will turn into a wanted signal in SHO)

Distance between cells suitable for neighbours should be considered

Increased numbers of soft handovers can cause capacity problems

TEMS Scanner WCDMA and UE (applications)

Scanner UE


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An overview of cluster performance

based on scanner Best Serving

CPICH RSCP and Ec/Io measureddata.

An overview of cluster performance

based on UEs perceived Best Serving

CPICH RSCP and Ec/Io measured data. Data are used to assist detailed

voice/video/data call analysis.

Events

Handover

Blocked call

Drop call

Poor Coverage

Missing Neighbours

Pilot Pollution (overshooting or poorcoverage)


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Optimisation Example 1 Scannerv.s. UE data

Scanner Best Serving CPICH RSCP Plot


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Measured Scanner Best Server CPICH RSCP Plot.

UE Best Serving CPICH RSCP Plot


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Measured UE Active Set Best Server CPICH RSCP Plot

Scanner Best Serving CPICH Ec/Io Plot


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Measured Scanner Best Server CPICH Ec/Io Plot

UE Best Serving CPICH Ec/Io PlotNote: The Ec/Io of UE is

worse than Scanner dueto missing neighbours

( d b


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Measured UE Active Set Best Server CPICH Ec/Io Plot

(some are caused by

overshooting cells)

UE Best Serving CPICH Ec/Io Plot


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Measured UE Active Set Best Server CPICH Ec/Io Plot

Identify problem areas


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Optimisation Example 1 Cont.Poor Ec/Io

Identifying area of concern Poor Ec/Io e.g due toOvershooting


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Both SC27 & SC43

from site 53 are

overshooting the area

Identifying area of concern Poor Ec/Io Poor e.g.due to Overshooting-Cont.(TEMS Map)


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128Geographical Location for drop call near site 32472

Poor Ec/Io Poor Ec/Io due to Overshooting-Cont.


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Individual SC RSCP Plot for SC27 Individual SC RSCP Plot for SC43

Site 53 has 2 cells, 30 meters high and with no tilt.

Overshooting, Cont. (another area)


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Geographical Location for drop call near site 3855

Caused by Overshooting site 53 (SC27)

Overshooting, cont.(SC27 P-CPICH RSCP plot)


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Individual SC RSCP Plot for overshooting cell

(SC27)

Recommending Optimisation changes

Apply 4 degrees down tilt to Both Sector 1& 3 of site 53


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Optimisation Example 1 cont.Active Set

Optimisation Example Cont..-Pilot Pollution(Active Set related)


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Lack of Dominant Cell

but margin o.k. Ec/Io

for SC171, SC155,

SC99 in AS.

SC43 has strong RSCP & Ec/Io

and is overshooting the area.


Once again, apply 4 degrees down tilt to SC43 (sector 3 of site 53) Then re-drive the area and check dominate serving P-CPICH and Ec/Io of the area.


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9Tips: The report generator can also show an event call more than 3 strong SCswhich indicates there can be pilot pollution issue.

Optimisation Example 1 cont.Poor Coverage

Poor RSCP and Ec/Io for

Serving Cell (SC150) and

M it i C ll (SC53 &


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136

Monitoring Cells (SC53 &

SC94).

Recommending Optimisation changesfor Example on Poor Coverage

Solution:


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137

Location of Poor Coverage Area near

planned sites 31061 & 34800

Solution:

Need planned sites 34800

to be on air

planned sites

Neighbour Planning

3G->3G


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Use planning tool (e.g. Atoll) to assist on initial neighbour planning.

Select cells with overlapping coverage to serving cell (e.g. other cells inthe serving cell site & the first tier cells around the serving cell).

Special cases: motorway (high speed drive).

Add neighbour relations mutually.

Priorities neighbour list. Avoid long list of neighbours.

Avoid 2nd order SC clashes.

Drive test and perform drop call analysis after initial neighbour lists are on

the network. Add missing neighbours and re-drive test the area.

Neighbour Planning -Avoid long list ofneighbours

When Soft/Softer Handover is executed, a new Active Set is created.


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According to the new Active Set, the new list of neighbours (modification)

is sent to the UE in a new MEASUREMENT CONTROL message. If the new list of neighbour is greater than max allowable numbers of

neighbours for one cell (e.g. 32 neighbours), the excessive numbers of

neighbours will be truncated.

To avoid this, prioritise the neighbour list. Also, keep neighbour list short. (e.g. 16 neighbours per cell).

Neighbour Planning-Motorway example

Car speed drive

ld l


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would pass several

cells quickly, thusmay need more more

neighbours along the

motorway.

Neighbour Planning-Avoid 2nd order SCclashes

Cell B and D have the same SC

If the UE is in softhandover between cells A

d C d ll B d D


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Cell B and D have the same SC

UE in soft handover between Cell A

and C

and C, and cells B and D

have the same PSC thenthe UE will be sent thisPSC twice.

This will prevent the UEfrom being able to

accurately report on thesePSCs and make handoverdecisions.

Solution: Avoid use sameSC in nearby cells.

Neighbour Planning

3G->2G


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Since the 2G network is more mature than the 3G network, most likely, a

3G site would have a 2G equivalent site. If so, use same 2G neighbour list for 3G (including the 2G equivalent cell).

If not, apply same principle for 3G neighbour planning to 2G.

Each 3G cell and specify that a mutual 3G relation is to be added on the

2G cell.

Neighbour Planning (TEMS Map), Cont.


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Click on the

serving cell to

show its defined

3G neighbours.


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Lunch!


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Analysing problem calls

Common Problem Summary

Description Category

9O


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9Overshooting Parameter

9No coverage RF

Missing neighbouring relationship Parameter

Call dropped after active set update UE

PDP Context Activation Failure Core Network problem

Missing neighboring relationship

Symptom:


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Before connection drop, the CPICH_Ec/No of the serving cell gets worse and

detected neighbour has better Ec/No. After connection drop, when a new call is

established, the UE will connect to another cell with better CPICH_Ec/No, which is

not in the previous monitored set.

Possible solution:

Add the missing neighbour relationship to the neighbouring list.

Remove that cell coverage if it is an overshooting cell.

Missing neighboring relationship, cont.


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Before dropped call:Detected Neighbour has good

RSCP level.



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UE keeps sending

Measuerment Reportsreporting (event 1a forSC83) but no responsefrom UTRAN.



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After dropped call:

UE is connected to the missing neighbour cell (SC 83)



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dark blue = footprint W00528021

light blue = footprint W10646031

Planned site


Add SC83 SC19as neighbours

Note: site 3978 is a

planned site.


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Use .cel file to help tosee existing

neighbour relations

Planned site

No coverage

Symptom:

All di f b d f


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All radio performance are very bad performance

Best serving CPICH_RSCP is low, e.g. < -105dBm

Best serving CPICH_Ec/No is low, e.g. < -16dB

UE_Tx_PWR is high. Normally, the UE releases the connection by itself.

After connection drop, the UE cant find any suitable cell for a while.

Possible solution:

The unique solution is to add new site.

No coverage,cont.

Poor RSCP Level and

Ec/No Level


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Drop after active set update

Symptom:

Normally, the observed sequent messages in the UE side are:


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UTRAN -> UE: Active set update (to request the UE to remove a cell, e.g.SC281)

UE -> UTRAN: Active set update complete

UTRAN -> UE: Measurement Control (update neighbour list)

UE -> UTRAN: Measurement report (to propose to add7)

UTRAN -> UE: Active set update (to request the UE to add SC 137)

DROP.......(since no Active set update completion was sen after 12 secs ) The radio performances no matter DL and UL are very good.

Possible solution: No solution, check this problem with UE vendor.

Soft/Softer HandoverRadio Link Addition

and Radio LinkRemoval.


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BLER is getting worse

RF condition

is o.k.

Drop after active set update, Cont.


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No Active Set

Completion was sent

after Active Set

Update.

PDP Context Activation Failure

Symptom:

All radio performance are good


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However, PDP Context Reject by

UTRAN.

Possible solution: No solution, check

this problem with Network equipmentvendor.

Good RF

condition


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BACKUP

RRC States

CELL_DCH: In this state the UE has a dedicated connection to the Radio AccessNetwork. It is used:

For services requiring Conversational QoS, like voice and video call, because thestrict time delay constraints can only be achieved through a dedicated connection.

For High bit rate PS services because these can only be achieved through a


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g y g

dedicated connectionIn this state the UE is in constant contact with the network which knows itsposition on cell level, because it communicates (via cell update) every time itchanges cell

CELL_FACH:In this state the UE does not have a dedicated connection to thenetwork relying instead on common channels (RACH./FACH) which it shares withother users It is used

For PS services that require the transfer of low amounts of data. If more capacity isrequired the UE is promoted to CELL_DCH

For signalling with the networkIn this state the UEs position is known by the network on cell level

RRC States

CELL_DCH: In this state the UE has a dedicated connection to the Radio Access

Network. It is used: For services requiring Conversational QoS, like voice and video call, because the

strict time delay constraints can only be achieved through a dedicated connection.

For High bit rate PS services because these can only be achieved through adedicated connection


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In this state the UE is in constant contact with the network which knows itsposition on cell level, because it communicates (via cell update) every time itchanges cell

CELL_FACH:In this state the UE does not have a dedicated connection to the

network relying instead on common channels (RACH./FACH) which it shares withother users It is used

For PS services that require the transfer of low amounts of data. If more capacity isrequired the UE is promoted to CELL_DCH

For signalling with the network

In this state the UEs position is known by the network on cell level

RRC States




In this state the UE is in constant contact with the network which knows its


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position on cell level, because it communicates (via cell update) every time itchanges cell

CELL_FACH:In this state the UE does not have a dedicated connection to thenetwork relying instead on common channels (RACH./FACH) which it shares with

other users It is used For PS services that require the transfer of low amounts of data. If more capacity is

required the UE is promoted to CELL_DCH


RRC States




In this state the UE is in constant contact with the network which knows its


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position on cell level, because it communicates (via cell update) every time itchanges cell

CELL_FACH:In this state the UE does not have a dedicated connection to thenetwork relying instead on common channels (RACH./FACH) which it shares with

other users It is used For PS services that require the transfer of low amounts of data. If more capacity is

required the UE is promoted to CELL_DCH


Physical layer AspectsCompressed Mode Methods

Three methods are available to create transmission gaps PuncturingPuncturing: additional puncturing/fewer repetitions are performed compared

to normal mode to be used only in DL

to be used only in the case of mapping to fixed positions


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y pp g p

scrambling and channelisation code remain unchanged

Spreading Factor ReductionSpreading Factor Reduction: SF is divided by 2 can be used in UL and DL

can be used with mapping to flexible positions

to be used only when SF>4

only 2nd DTX insertion and physical channel mapping is modified

may lead to channelisation code shortage and the need to use a secondary scrambling code

Physical Layer AspectsCompressed Mode Methods

Higher Layer SchedulingHigher Layer Scheduling: only a subset of the TFCS is used during a compressed radioframe to create the gaps

can be used in UL and DL

can be used with fixed and flexible mapping

to be used only for radio bearers that allow some buffering, e.g interactive and background classes


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rate matching remains as in normal mode

Use of Multiple Methods in ParallelUse of Multiple Methods in Parallel

There are generally no restrictions within the standard on the use of different methods when multiple pattern

sequences are used in parallel, however, some precautions must be taken.

E.g., Compressed mode by puncturing affects the rate matching across the longest TTI in the CCtrCH while compressed mode by

higher layer scheduling works on a radio frame basis. For these two methods to co-exist

Documents

UMTS_RF_Optimization_Workshop_Oct2004_v2.pdf