88778702 informacion 3g by Emerson Rodrigues Setim

Telefónica Perú Capacity Management 3G Network

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Outline • •

Introduction Capacity Areas in UTRAN 1. 2. 3. 4.

•

Air Interface WBTS HW Resourses RNC Transport IuB

Iu Monitoring • • •

Iu-CS Iu-PS Iu-R

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Introduction

WCDMA network interfaces and internal resources should be monitored For internal use 3 ÂŠ Nokia Siemens Networks

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Introduction â&#x20AC;˘

The various measurement were used to identify the capacity issues and their negative impact on accessibility (CSSR) of the various RABs:

1. CS speech (AMR) 2. PS data (R99) 3. HSPA data

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Capacity Areas in UTRAN • Essential to monitor the available resources in UTRAN – Capacity from initial dimensioning phase may no be sufficient in some cases – Marketing campaigns lead to higher resource utilization

• Capacity bottlenecks impact the call setup success rates (CSSR) – Mobile user perceives poor setup success rates directly

• With these measurements, network capacity can be monitored in a proactive mode – Capacity upgrades can be triggered taking into account existing lead times HW units, internal procedures like planning or implementation

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Capacity Areas in UTRAN During call set-up [RRC, RAB] several resource areas are checked and physical / logical resources allocated. Air Interface

WBTS HW Resources

Transport

1 – Radio resources UL interference

3 – DMCU

DL transmisson power

allocation

DL Codes 1a – Code resources

DSP processing

RLC/MAC

IuB FSP/ WSP capacity 2 – WBTS resources For internal use (Channel Elements) 6 © Nokia Siemens Networks Presentation / Author / Date

(N*) E1 capacity / AAL2 4 – Iub resources (transmission)

RNC

Call Setup Success Rate - CSSR CSSR for a specific service is calculated the following way: CSSR any service = RRC connection setup & access X RAB setup & access any service

RRC part

RAB part

For RAB setup & access phase we can distinguish various failure causes: SETUP PHASE:

ACCESS PHASE:

• due to AC

• due to UE

• due to BTS

• due to RNC

• due to Transport • due to RNC

Failures due to UE

• due to Frozen BTS

• are not related to capacity issues in the network

• due to AAL2 iuB, License, AAL2 IuCS, anchoring, UE For internal use capabilities, not supp. params 7

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• related to UE problems

Decision criteria • AMR accessibility • PS R99 accessibility No

• HSPA accessibility

Accesibility < 99% Yes

Radio resources Failures due to AC >1%

Cell OK

Channel elements Failures due to BTS >1%

Transport resources Failures due to TRANS >1%

RNC internal resources Failures due to RNC >1%

Additional KPI check & optimization (if necessary) Lack of Radio Resoures

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Lack of Channel Elements

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Lack of Iub resources

Lack of RNC resources

RAB setup failures 1. Admission Control (AC) failures – RADIO •

Indicates lack of radio resources: – DL power ▪

Measurement of PtxTotal, transmission power of NonHSDPA, HSDPA etc.

– UL interference ▪ ▪

Measurement of RSSI Measurement of PrxTotal and PrxNoise

– DL channelization codes: ▪ ▪ ▪ ▪

Channelization code occupancy (min, max, avg) Channelization code blocking rate HSDPA code usage HSDPA code downgrades

– Rejection rate in downlink and uplink (SRB, AMR, CS data, PS data) due to congestion – Common channel load (RACH, FACH, PCH) – typically not a problem

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RAB setup failures 1. Admission Control (AC) failures – RADIO ‘

• AMR accessibility

Failures due to AC >1% High nonHSPA load

DL power

Marginal Load Time Share DL > 50% Overload Time Share DL> 2%

UL interference Noise floor of the System >-90dBm

• PS R99 accessibility

Channelization codes Spread. Code Blocking Rate in DL >5%; SFxx Blocking Rate high

Average DL R99 Load > PtxTarget

High nonHSPA load R99 power >> HSDPA power

Marginal Load Time Share UL > 50%

Max_Code Occupancy >95%; Avg_Code Occupancy >80%

Overload Time Share UL> 2% Average UL R99 Load > PrxTarget

High DL load

Yes

Posible to reduce R99 usage?

High UL interference/load

Posible to reduce the code usage?

Posible to optimize throughput?

Upgrade BTS power

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High chan. Code utilization

Yes

No Yes

External Interference

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Upgrade to 2nd carrier

RAB setup failures 1a. HSDPA accessibility • Indicates problems for access of HS-DSCH (HSDPA access failure rate): 1. Due to UL DCH • Problems of return UL return channel • Related to R99 radio resources 2. Due to TOO MANY HSDPA USERS • Licence limit – 48 users  HSDPA license upgrade to 64 users • R99 is selected, which can cause capacity problem in use of radio resources  Check radio resources for R99 • If licence upgrade is not sufficient, the Dedicated HSDPA scheduler is an option 3. Due to BTS (channel elements) 4. Due to Iub (transmission) 5. Due to RNC

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RAB setup failures 1a. HSDPA accesibility Radio related issues

HSDPA accessibilit y < 99%

HSDPA Access FR due to UL DCH

Others DCH Selected due to too many HSDPA users

Go to HSDPA Access FR due to Iub

> 0.5%

HSDPA Access FR due to BTS

Problem in R99 ? 1. HSDPA 64 users

License upgrade OR LATER

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2. HSDPA Dedicated Scheduler upgrade

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HSDPA Access FR due to RNC

TRANSPORT failures Go to BTS failures Go to RNC failures

RAB setup failures 2. BTS failures •

Indicates lack of WBTS baseband resources = channel elements (CE): – Measurement of available CEs (min, max, avg) Measurement of usage of CEs:

– ▪ ▪

Fast

Failures due to BTS >1% CE utilization AVG_CE_USAGE > 80% MAX_CE_USAGE >95%

High CE utilization

In UL, DL (min, max, avg) Per service CE usage can be reduced?

WBTS HW upgrade (system module)

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Yes

RAB setup failures 3. RNC failures

Fast

Failures due to RNC >1%

•

Indicates lack of RNC internal resources – DSP Service Statistics

– – – –

Measurement DSP Resource Utilisation Measurements DSP State Change Measurements DSP Load Measurements Iub, IuCS, IuPS throughput measurement at RNC

DSP load RNC_Unit Load: AVG_Load >80% MAX_Load >95%

High DSP load

RNC HW upgrade Traffic load RNC_Traffic Load: Iub Traffic Load IuCS Traffic Load IuPS Traffic Load

High Iu Traffic

RNC Interface capacity upgrade For internal use 14 © Nokia Siemens Networks

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RAB setup failures 4. Transport failures

Fast

Failures due to TRANS/AAL2 Iub >1% Iub Reservations

•

Indicates lack of transport resources –

Traffic load measurements ▪ ▪

–

Peak_UP_CAC Reservation >90%

High Iub load

CAC reservations ▪ ▪ ▪

–

Allocated Average Capacity of CBR VCC Allocated Capacity per ATM VCC (cps) AAL2 connection reservation success rate

Number of AAL2 Connections ▪ ▪ ▪

–

Average VCC Ingress/Egress utilisation Average VPC Ingress/Egress utilisation

AVG_UP_CAC Reservation > 80%

Average AAL2 connection utilisation Max_AAL2_connections (248 max) Max_AAL2_connections_HSPDA

Shared HSDPA AAL2 allocation utilisation

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Yes

Posible to reduce Iub utilization?

Iub upgrade

Yes

Additional tasks • Even if all the capacity issues would be resolved, the 100% accessibility can not be expected • RF optimization (e.g. overshooting cells) – Propagation delay measurements – CQI measurements – RSCP, Ec/Io measurements

• Mobility optimization – Soft handover – Inter-system handover

• Failures due to UEs can not be avoid

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Iu Monitoring • The scope of this presentation is RNC interfaces monitoring using measurements in the RNC and in the BTS

MGW

Iu-CS

Iub

RNC SGSN

BTS

Iu-PS Iur RNC

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Content 1. ATM load measurements 2. AAL2 CAC measurements

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ATM Load Measurements - Overview ATM Load Measurements in RNC

• Virtual Path Connection (VPC) • Virtual Circuit Connection (VCC) • ATM interface ATM interface

Virtual channel

Virtual path

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AAL2 connection

ATM VPC and VCC Measurements • ATM VPC/VCC measurements count cells per VPC/VCC during measurement period • Up to 1024 VPCs and all VCCs (RU10 onwards) can be measured per RNC at the same time • Enables calculating average throughput over the measurement period

Cells/period Configured capacity

Actual traffic

Measurement period

Measured average traffic

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ATM VPC and VCC Measurements • Iu-CS, Iu-PS and Iur can be measured as well • Use of ingress and egress counters – Iub in downlink direction is measured using egress counters – Iu-PS in downlink direction is measured using ingress counters Egress

Ingress

direction

direction MGW

Iu-CS

Iub

RNC SGSN

BTS

Iu-PS Iur RNC

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ATM Interface Measurement • ATM interface utilization and traffic per service category CBR, UBR and UBR+

• The ATM interface level measurement is relevant if you have unshaped VPCs with UBR+ VCCs inside and the sum of VCC PCRs exceeds the interface capacity – Otherwise the ATM CAC and/or VCC/VPC configuration will prevent overload possibility

• Potentially useful for Iu if IuPS and IuCS are on their own NIS cards.

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ATM interface

Virtual channel

Virtual path

AAL2 connection

Content 1. ATM load measurements 2. AAL2 CAC measurements

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RNC AAL2 Connection Admission Control • Bandwidth requirement is affected by – ALC parameters, ALC set (for DCCH), Activity factors – Delay requirement, loss tolerance

ATM VCC PCR

New connection up to this capacity would fit in AAL2 reservation for existing connections

New connection requiring this much capacity would be blocked

– Done for common channels, SRB, RT DCH, NRT DCH, Streaming HSDPA and SharedHSDPAAllocation – VCC bundle is a special case For internal use 24 © Nokia Siemens Networks

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Summary RAN capacity monitoring processes are focused on the following interfaces and network elements: • Radio Interface capacity – WBTS power, code tree • Iub capacity – Transmission capacity • Node B capacity –WBTS Base band processing capacity • RNC processing capacity • Iu-CS, Iu-PS and Iur traffic Monitoring / Interface

Proactive Monitoring

Air Interface

Iub Interface

HW Channel Element

RNC Capacity

-BTS power DL/UL -Channelisation code utilisation -S-CCPCH & PRACH load

-Iub traffic load -Resource reservation

-CE utilisation

-RNC traffic load -Unit load

-Setup failure due to AC -Service rejection ratio -Code blocking -RB downgrade/release

-Setup failure due to transmission -Resource reservation success rate

-Setup failure due to BTS

-Setup failure due to RNC

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Thank You!

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