Slide 1

UMTS Optimization Course

WCDMA Introduction Idle Mode Behavior (Air interface review)Cell Selection and Reselection Power control Strategy Handover in 3G network Capacity management Channel switching HSDPA 3G Protocols KPIs

Course ContentNetwork ArchitectureRadio team is the responsible of handling the Air Interface network in terms Coverage Capacity Quality

BTSGSM BSSRNCWCDMA Systems RANMSC / VLRGMSCOther PLMNFixed NetworkMGWSGSNGGSNIP NetworkAbisGbIubIuIu-PsIu-CSPCUBSCNode-b

Network ArchitectureAntenna theory

Radiating Element (Antenna)Antenna Device responsible of converting the electric signal to a radiating waves.Antenna is a passive element not active elementAntenna as Isotropic SourceCompletely non-directional that radiates equally in all directions. The isotropic antenna exists only as a mathematical concept Isotropic Source (Contd)How could we reform the antenna pattern?Current amplitude. current phase.Geographical shapeMain BeamSide LopsBack lopsOmni-Directional Antennas

Omni-directional antennas have a uniform radiation pattern with respect to horizontal directions. Used in the indoor solutions

Uni-Directional Antennas

A uni-directional antenna has a non-uniform horizontal and vertical radiation patternUsed in sectored cells. The radiated power is concentrated in one direction.

Antenna typesMain Antenna ParametersHorizontal Beam-width

Vertical Beam-width

3dB down3dB down3dB down

3dB downHorizontal Pattern Vertical Pattern GSM site equipment (contd)Main Antenna Parameters (Contd)Tilting

Electrical TiltMechanical tiltMultiple Access TechnologiesIs the Way at which You take Resources FDMA/TDMA Frequency TimeTimeFrequencyCDMA CodeFrequencyTimeCodeTimeFrequencyFDMA FrequencyMultiple Access Technologies2G System use FDMA/TDMA FDMA/TDMA Frequency TimeTimeFrequency

Freq 1013 Kbps7

07

7Time SlotFrequency7

Time Slot HR6.5 Kbps6.5 Kbps0.577 ms2G Sites (Contd)142G Sites

UE Different between 2G Sites by Frequencies

Freq 1Freq 2Freq 3Freq 4Freq 5Freq 6Freq 7Freq 8Freq 9Freq 10In 2G we have to make frequency plan to ensure that the customer has good voice qualityReuse ConceptF3F7F5F4F7F1F6F2F3F7F1F2F3F4F5F6F3F72G (reuse > 1)The Frequency reuse should ensure minimum interference in the field16Interference Internal InterferenceExternal interferenceReuse Concept (Contd)Adjacent Channel interferenceCo-channel Interference

Co-channel Interference Very bad Voice quality Most Probably cause dropped calls Bad Quality AreaAdjacent Channel interference Very bad Voice quality Reuse Concept (Contd)FrequencyF1F2F3F4F5F6F7F8F9

Bad Quality AreaReuse Concept (Contd)External interference Jammer SourceVIP Visits Mosques

Telecom Egypt Reuse Concept (Contd)

Reuse Concept (Contd)The interference increase when there is ducting phenomena

3G System use WCDMACDMA CodeFrequencyTimeCode3G Sites

UE Different between 3G Sites by Scrambling Code

SC 1SC 2Sc 3SC 4SC 5SC 6SC 7SC 8SC 9SC 10Freq 1Freq 1Freq 1Freq 1Freq 1Freq 1Freq 1Freq 1Freq 1Freq 1 In WCDMA, all cells use the same carrier frequency but different scrambling codes. This means no frequency planning, but scrambling code instead!Reuse ConceptF1F1F1F1F1F1F1F1F1F1F1F1F1F1F1F1F1F1SC 3SC7SC5SC 4SC 7SC1SC6SC 2SC3SC 7SC 6SC2SC3SC4SC5SC 6SC 3SC73G (Frequency reuse = 1)24CDMA PartyThe CDMA Party

26RussianJapaneseSpanishItalianWhat do YOU hear...If you only speak Japanese?If you only speak English?If you only speak Italian?If you only speak Japanese, but the Japanese-speaking person is very near to you?If you only speak Japanese, but the Japanese-speaking person is very far from you?If you only speak Japanese, but the Spanish-speaking person is talking very loudly?The CDMA Party

27Both signals combinedin the air interfaceSC Code 1FrequencyAmplitudeSignal 1SC Code 2FrequencyAmplitudeSignal 2Spread SpectrumProcessing Gain SC Code 1Signal 1 is reconstructedSignal 2 looks like noiseBoth signals arereceived togetherAT THE RECEIVER...Two Transmitters at the same frequencySpread Spectrum Multiple AccessFrequencyFrequencyFrequency28PG: How much is the data spreaded?Since all users have the same modulation bandwidth, the processing gain becomes larger for connections using lower data rates. This enables the system to transmit with lower power, and thus lower interference is created to the rest of the system.No

PowerFreqDigital SNR: Eb/No

Energy per bit (Eb) equals the average signal power (S) divided by the data bit rate (Rb)

Noise power density (N0)The total noise power in the signal bandwidth, divided by the signal bandwidthSpread Spectrum Multiple Access (Contd)

Energy per bit (Eb) - to - Noise RatioThe Signal-to-Noise Ratio (SNR) times the SSMA Processing Gain

If you need to decode the service you should have Certain Eb/No

To achieve the required Eb/No for each service their must be certain Probability of error Example WCDMA is based on QPSK modulation technique 0246810121410-1210-1010-810-610-410-2100Eb/No (dB)Pe (Probability of bit error)

Voice ServiceSpread Spectrum Multiple Access

If the BLER requires an Eb/No of 5dB for a certain service and the processing gain(Gp) is 25dB for the service, it means a C/I down to 20 dB is still acceptable

Rc : Chiprate 3.84 McRi : Service bitrate GpPower+GpSignal (Eb)Interference& Noise (No)1 Carrier (5MHz)20 dB+5 dB1 Carrier (5MHz)PowerSignal (Eb/No)Interference (No)Eb/No = 95dBm Other PLMNs that dont fulfill high quality criteriaAutomatic PLMN selectionIDLE MODE (Contd)

Initial Cell Selection Automatic ModeManual PLMN Selection UE displays all the available PLMNS after carriers scanning All the available PLMNs will appear End User will chose one PLMN

2-RoamingUE will be able to obtain services from another PLMN Same country (national roaming) Another country (international roaming) Every 30 minutes the UE try to reselect its home PLMNIDLE MODE (Contd)3-Cell selectionCell selection procedure Squal = Qqualmeas qQualMin

Qqualmeas is CPICH Ec/No qQualMin is minimum required Ec/No Qqualmeas > qQualMin

Srxlev = Qrxlevmeas qRxlevMin

Qrxlevmeas is CPICH RSCP qRxlevMin is minimum required RSCP Qrxlevmeas > qRxlevMin The cell consider as accepted if

Squal > 0 and Srxlev > 0IDLE MODE (Contd)4-Cell Re-selectionCell reselection procedure When it occurs When cell on which it is camping is no longer suitable When there is any neighbor with better quality than the selected one3G F13G F2GSM3G F11- Intra frequency measurements starts when

Squal