2G vs3G Comparison EssentialsMultiwireless Sdn BhdPrepared by: HuzainiBasic FundamentalCourse

BASIC CONCEPTMultiwireless Sdn Bhd 22 May 2010*2G - GSM3G - WCDMAFrequency

FDDCode

CDMATime

TDDMaxis WCDMA frequencies*:f1 10686 (DL) / 9712 (UL) - primaryf2 10637 (DL) / 9687 (UL)f3 10662 (DL) / 9736 (UL)frequency* Note: Different operator have different frequencies and different strategy advice by Vendor (Huawei/Ericsson/NSN)For CSFor PSBandwidth = 5MHzbandwidthChip rate = 3.84 Mchip/schip rateFrame length = 10 msframeMaxis GSM frequencies:900MHz, 1800MHzfrequencyBandwidth = 200kHzbandwidth

SCRAMBLING CODES (SC)*SC: 1SC: 17Scrambling Code:Using pseudo noise (PN) codesUsed to differentiate cells in the downlink (DL)Range is 0 - 512SCSC: 9, Service: CS CallDL Channelization code: C128,5Spreading factor: 128User bit rate: 12.2 kbpsSC: 9, Service: PS DownloadDL Channelization code: C8,2Spreading Factor: 8User bit rate: 384 kbpsChannelization Code:Using Orthogonal Variable Spreading Factor (OVSF) codesFully orthogonal, i.e. do not interfere with each otherUsed to separate different users/cellLimited codes per cellOnce a code is chosen, any codes on the same branch above or below the used code cannot be used (refer diagram below)SFSC: 418SC: 9Multiwireless Sdn Bhd 22 May 2010

Spreading FactorUser DL Bit Rate (kbps)User UL Bit Rate (kbps)83841281612864326432643216128168

HANDOVER (1)Multiwireless Sdn Bhd 22 May 2010*2GCell13GCell1f1IRATDedicated or idle (reselection)Idle (reselection)3GCell2f1SOFT HANDOVERActive Set:Up to 3 cells in soft handover (sHO), i.e. 3 AS. This means a UE can be served by up to 3 cells at the same time. Note that 3 AS equals to using 3 cells resources at the same time.ASThings to defineMotorola: inter_rat_enabled, 2g>3g neighbours1Ericsson: qsi, 2g>3g neighboursParameter2G vs 3GRxLev = Signal strength = RSCP RxQual = Signal Quality = Ec/IoBCCH/ARFCN = Frequency Channel / Code = Scrambling Code (SC)Monitored Neigbour / Detected NeighbourMonitored Neighbour (MN): Neighbour already defined2, can be added as an AS if criterion is metDetected Neighbour (DN): Neighbour not defined in the neighbour list, need to be added TWO-WAY if it is a valid missing neighbour. A DN whose RSCP is too close to the strongest server and not added as a neighbour will become an interferer.MN/DNSOFT HANDOVERIRATDedicatedTEMS Snapshot3GCell3f2HARD HANDOVERDedicatedInter-frequency HOIntra-frequency HOHARD HANDOVER

HANDOVER(2)*Event 1a - A Primary CPICH enters the Reporting Range e1aEvent 1b -A Primary CPICH leaves the Reporting Range e1bEvent 1c - A non-active primary CPICH becomes better than an Active Primary CPICH e1cEvent 1d - Change of Best Cell e1dEvent 2d - The estimated quality of the currently used frequency is below a certain Threshold e2dEvent 2f - The estimated quality of the currently used frequency is above a certain threshold e2fEvent 3a - The Estimated Quality of the Currently Used UTRAN Frequency is below a Certain Threshold and the Estimated Quality of the Other System is above a Certain Threshold e3aMaxis default valuesMultiwireless Sdn Bhd 22 May 2010

ParameterMeas. QEricNSNe1aEc/No33e1bEc/No56e1cEc/No12e1dEc/No7.54e2drscp-104-102e2frscp-101-97e3arscp-95-100

OPTIMIZATIONMultiwireless Sdn Bhd 22 May 2010*TEMS SnapshotRSCP = COVERAGEIt is equivalent to RxLev in GSMCoverageEc/No = QUALITYIt is equivalent to RxQual in GSM. Very important to optimize network to have good quality (>-12dB)QualityOPTIMIZATION CONCEPTTo have best Ec/No (not necessarily RSCP) by minimizing other cells interference. This means optimizing a cells coverage with balancing between RSCP and Ec/No. Ideally, at one point in time, you should have only 1AS only. But for practicality, it should be less than 3 cells (including best server) within 6dB of the best servers RSCP (above example would have 4 cells)3G OptiMETHODS OF OPTIMIZATIONTilting of overshooting sitePower down of overshooting site with max tiltsNeighbour addition of DNsReengineering, e.g. antenna swingMethodsCommon Pilot ChannelUse for channel estimation reference at the terminal; scrambled with cell specific primary SC; DL channel with a fixed rate of 30 kbps or SF256CPICH

RESOURCES & CAPACITYMultiwireless Sdn Bhd 22 May 2010*E1 CAPACITYType: Site-levelNote: This resource is for signaling and traffic between Node B and RNC (highest priority among all resources mentioned here).Congestion Resolution: E1 upgradeIUBCHANNEL ELEMENTType: Site-level Note: This resource shared between sectors within one NodeB. It is used to process different type of services, e.g. CS, PS, HSDPA, 1 CE = 1 Voice CallCongestion Resolution: Channel card activation or additionCE/CHCPOWERType: Cell-levelNote: Output power on the downlink is shared between UEs.for their respective trafficCongestion Resolution: Power upgrade or 2nd CarrierPOWERCODEType: Cell-levelNote: This is referring to the channelization/OVSF code resource which is one per service (more codes for HSDPA)Congestion Resolution: 2nd CarrierCODERNC

RF ToolsMultiwireless Sdn Bhd 22 May 2010*TEMS InvestigationNEMO GenexCoueiROMES Rodge & SchwarzSwissQual

*Basic Tems Investigation 7.1.3 Overview

What to focus on 3G tems? Line Chart WCDMA/GSMRadio Parameters WCDMAServing/ Active Set- Neighbours WCDMAMapLayer 3Layer 2 Radio Parameters GSMCurrent Channel GSM Serving Neighbors By Band GSM

*Line Chart WCDMA/GSM

*Radio Parameters WCDMATx Power- UE transmit power in dBm. Valid only in connected mode. This window presents a collection of information elements describing the status of the radio link and some more general radio conditions. UTRA Carrier RSSI- Total energy measured by the UE in the 5 MHz frequency band. SIR-Signal-to-interference ratio measured by a UE on the DPCH. SQI- Speech Quality Index for WCDMA. The range is different depending on the AMR speech codec mode. The maximum SQI values are as follows: 12.2 kbit/s: 30 dBQ 10.2 kbit/s: 28 dBQ 7.95 kbit/s: 28 dBQ 7.40 kbit/s: 27 dBQ 6.70 kbit/s: 27 dBQ 5.90 kbit/s: 24 dBQ 5.15 kbit/s: 21 dBQ 4.75 kbit/s: 19 dBQ !!Target SIR should lower than SIR- UE will power down

*Serving/ Active Set- Neighbours WCDMA

Active SetMonitored NeighboursDetected Neighbours

*Layer 3/ Layer 2Layer 2 messagesIndicate the basic call event.Example: Call setup, Handover, Dropped Call, Cell Reselection etc.Layer 3 messagesIndicates the system information & check the health of the call.

*Case StudiesVoice Call

IRATCoverage (Low RF)Missing Neighbour (Detected Neighbour)/ Overshooting Cell2G-3G Idle Mode Reselection3G-2G Idle mode Reselection

Video CallWhat different between Voice call and Video call?What is MOC and MTC?

3.Packet Service (PS)What is PS?PS vs Car speed during drive test?

*IRATThe IRAT threshold: Base on Ec/No= -12 ORBase on RSCP= -104 dBm

*Coverage (Low RF)Low RF in 3G?

AS/ MN with average RSCP < -100 dBm for outdoor & with average Ec/No

*Missing Neighbour (DN)/ Overshooting CellDN/ Overshooting Cell?

It will be captured as DN with good RSCP & Ec/No. Based on local knowledge, the RF is needed or it is an overshooting cell.

*3G-2G Idle Mode ReselectionHow?

Based on Ec/No threshold.

*2G-3G Idle Mode ReselectionHow?

Inter_rat parameter has to be enabled in 2G cell.A few parameters to be changed in 2G system in order for reselection.

*Video CallHow to differentiate between Voice Call/ Video Call?

DL Spreading Factor= 32 [ DL 64 kbps]On video call, no IRAT. Why? It is utilizing the CS64 RAB bearer.

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