3G WCDMA and 4G Practical OverviewPart 1

Noise and InterferenceN NoiseI Interference

TB Thermal (Johnson) Noise where (Kappa) Boltzmann constant

No Noise Power Spectral Density (PSD)It I0 + No = Total Noise plus Interference PSD

Noise Rise (NR) or Rise over Thermal (RoT) occurs in CDMA (based technologies) due to loading or traffic increase CELL BREATHING

Prior to deployment , check the Spectrum Cleanliness(Power Spectral Density of existing Noise and Interference )

Interference Jammer

Interference = Own Cell + Other Cell Interference

Spread Spectrum (SS)Shannons equation

C = B log2 (1 + S/N )

Principle of SS : If S/N (SNR) cannot be increased beyond a limit , increase B

Averages out the impact of interference

Types DS-SS and FH-SS FFH-SS and SFH-SS

Receiver Sensitivity = NF + TB + Eb/No PG

PG PROCESSING GAIN ; also known as Spreading Factor (SF)

WCDMA uses DS-SS spreading rate = 3.84 Mcps (= W)

This results in a Processing Gain , PG = W/R 26 dB

Achieve Frequency Diversity

Multiple Access (MA) TechniquesFDMASpectrum availability highly restricted per user ; time availability unrestricted.

TDMATime availability restricted per user ; spectrum availability unrestricted.

CDMABoth spectrum and time availability (relatively) unrestricted per user for communication

Orthogonal CodesMathematical property prevents mutual interference

Zero cross-correlation

Orthogonality Factor is generally considered in planning tools or other analysis

Orthogonality property tends to reduce due to real world propagation mainly reflections (highmultipath environment)

Maximal Length (ML) SequencesCan simply be generated by a shift register with feedback

Property of PN sequences in CDMA / Scrambling sequences in WCDMA

Codes are used for Scrambling

Good for multipath environment

Synchronization performance is good

Spreading vs ScramblingSpreading is used to achieve the bandwidth spreading (Spread Spectrum Direct Spread)

Walsh Code is used for Spreading

Scrambling is used to further spread and also to make further unintelligible the RF signal anddifferentiate sectors

PN sequence is used for Scrambling

Different sectors PN sequence is distinguished by RAKE receiver using their time offsetsPN_OFFSET

Correlator and RAKE receiverThe simplest example of a correlator is an EX-OR gate

Y = A B + A B = A B

Compares internally generated clock (PN sequence) with an offset PN signal

Basic building block of RAKE receiver

A RAKE receiver counters the effect of multipath fading.

LatencyLatencyLatency is the time it takes for a data packet to be sent and then an acknowledgement to be received from the other end

Few milliseconds is best value

CDMA OneIS-95A/ B Standard1.25 MHz Channel Bandwidth

Fully circuit switched connections uses IWF for data connections

Peak data throughput 14.4 kbps

QCELP or EVRC Codec (No independent TRAU as in GSM) Integrated in BSC

Codec rates:-Rate Set (RS) 1Rate Set (RS) 2

MSC can be eliminated if V5.2 interface is used ANLE Configuratione.g. BSC as Access Node (AN) and operator exchange as Local Exchange (LE)Sector AntennasBTS

CDMA 1x RTTIS-2000 standard1.25 MHz Channel Bandwidth

1x Spreading Rate of 1.2288 Mcps3x Spreading Rate of 3 1.2288 Mcps (MC-CDMA)RTT Radio Transmission Technology

Incorporates Packet Switched connectionsNew Packet Core Network component PDSN (similar to the GGSN in GPRS) PDSN manages PPP sessions between the mobile providers core IP network and the mobile station

Peak data throughput 156.3 kbps

Introduces QPCH (Quick Paging) ChannelAlso variable length Walsh Codes

Radio ConfigurationsRC1 RS1RC2 RS2RC3RC4

CDMA 1x ChannelsBasic CDMA One Channels

Pilot Channel Beacon channel ; carries no information. Strength indicated by Ec/IoPaging Channel Paging or broadcast of SMS , Neighbour List , System Parameters

Access Channel Used by MS to originate calls or respond to pagesTraffic Channel Bearer informationSync Channel System Time , Parameters , etc.

CDMA 1x Channels and Naming Convention

F-PICHF-PCH

F-TCH

R-TCH

CDMA 1x Data Users

CDMA Handoff

Ec/Io ThresholdsT_ADDT_DROPT_COMPT_TCOMP

Pilot SetsACTIVE SETCANDIDATE SETNEIGHBOUR SETREMAINING SETSupports make before break handoff mechanisms Soft and Softer handoff

Break before make only for inter-frequency HO

Soft HO tradeoff required with subscriber capacity

CDMA 1x Lucent SystemFlexent Modcell 3.0 BTSChannel card CCU64

Lucent 5ESS Flexent Autoplex

BSC functionality (ECP block) and VLR integrated in MSC

HLR

PDSN(Mumbai)ECPCBTSMSCHLR(Faridabad )VLRSMSC(Loaded with Cell Generic)

CDMA 1x EVDOEVDO Evolution Data Optimized

Quickest 3G evolution for CDMA 1x operators

e.g. , Lucent Flexent Modcell 4.0 BTS

Peak data throughput 2.4 Mbps (DL)

Achieves higher throughputs by using Quadrature Amplitude Modulation (QAM) and intelligently dedicating entire bandwidth for time slot dedicated to users on priority basis

CDMA One/ 1x Walsh Codes and Power SettingsWalsh Code Space Assigned by Indian Operators:-

64 Walsh Codes available from 0 to 63

Pilot Channel W0Paging Channel W1Sync Channel W32Traffic Channel W2 ~W31 , W33 ~W63

Lucent 3 W uniform Pilot powerMotorola 1.8 W 2.4 W 3 W variable setting >> flexibly control interference

DGU Digital Gain Unit108 For 3W Pilot Power

Linear Power Amplifier (LPA) Loading 4W (unloaded/ calibrated) or 36 dBm upwards to 20W

CDMA Planning ToolsAirPRO (Lucent)

Wizard

NETPLAN (Motorola) Monte Carlo Simulation , i.e. , predicts Noise Rise etc. for proposed trafficplanning for any given market

Planet EV (Marconi) MapInfo platform + RTT design support

Fault ManagementCDMA system (e.g. Lucent) :-Power Supply CardControl Card Channel Card Power Amplifier (Tx PA)Power Control (Cell Breathing management) Card

Hardware is organized as independent modules per carrier

Groups of hardware may be combined as one module based on vendor

GPS antenna system/ receiver hardware

VSWR of feeder cableSensitive to VSWR

Infrastructure faults

CDMA Test and MeasurementDrive TestQualcomm CAITGrayson Invex 3GAgilent E6474

Power CalibrationAgilent Power Meterwith ~30 dBm Attenuator

Spectrum MeasurementAgilentRohde Schwarz

IMT 2000Radio Transmission Technology (RTT)W-CDMAOperation Band (in India)2100 MHzDuplex Mode FDDChannel Bandwidth5 MHzSpread Spectrum TechniqueDS-SSSpreading Rate3.84 McpsPeak DL throughput384 kbps (Moving sub.)2 Mbps (Stationary/ walking sub.)CodecAMR-WBFrame length10 msFrequency Reuse Scheme1:1Power ControlAdaptive (SIR based) @ 1500 HzHandoffs Soft/ Softer/ Hard (IRAT)

Network ComponentsRadio technology is often called 3GSM as it is an enhancement overlay on exiting GSM networks

UTRANRNS (Radio Network Subsystem)Node-BRNC three roles SRNC, DRNC, CRNC UE

MGW

MSC Server

3G SGSN

GGSN

New Services PossibleMobile TV

Video on demand

Video conferencing

3GP is a multimedia container format defined by the 3GPP for 3G UMTS multimedia services

Tele-medicine

Location-based services

Radio Planning OverviewBetter link quality due to enhanced Processing GainLink budget at 50% loading assumption

Composite CPICH Power, RSCP, Ec/Io plot

Room for increased load

Coverage prediction Not Constant due to Cell Breathing

512 codes available Plan freely

Basic Cell Design DataCell Design Basic Data :

RNC id , Cell Id , MCC , MNC

Cell Name Parameter CELL in Ericsson

UARFCN = 5 frequency in MHz(10562 ~ 10838)

Band I(2100 MHz)

Scrambling Code : 0511

CPICH Power = 5% ~ 15% of total Node-B Tx power (commonly 10%)

Neighbour list

URA &/or LAC

Ericsson GSM UMTS Ngbr. Cell Design DataEricsson GSM to UTRAN Neighbour Def. CDD Examples (ALEX)

COEXUMTS (AXE : SUPCOEXUMTS) Support for coexistence of GSM and UMTSCOEXUMTSINT Time interval between traffic load checkingCOEXUMTSLSHEnables/ disables smooth GSM to WCDMA unloadingCELLCell name of external UTRAN cellCELLRIdentity of the neighbouring UTRANUMFIUMTS Meas. Freq. Information (GSM idle/ GPRS Ready, Standby)FDDQMINMinimum Ec/No for cell reselection to UTRANFDDQOFFSPRIOQSIFDDQMINOFFFDDRSCPMINMinimum RSCP for cell reselection to UTRANFDDARFCNARFCN of the external UTRAN cellSCRCODE Scrambling code of the external UTRAN cellUTRANIDIdentity of the external UTRAN cell (RNCID-CI-MCC-MNC-LAC)MRSLMinimum Ec/No for cell reselection to UTRANFDDMRRQSCQSCI(BSC Dump SUPCOEXUMTS = 1 , COEXUMTS = 0)

Diversity and RAKE Receiver

RAKE receiver has multiple fingers Searcher fingers and Correlators

Time Diversity

Equipped on Qualcomm MSM chip or variation on Qualcomm CSM chip

MSM Mobile Station Modem HandsetCSM Cell Site Modem CE (Channel Element)

Antenna Systems : New TechnologiesAvailable from key antenna suppliers:KathreinAndrewPowerwave

Typically antenna models support both UMTS 2100 and GSM 1800 bands

Advancements:Quintel Upto 10- to 12-port (Pentaband) antennas

Smart antennas

MIMO Technology

WCDMA HandoffSupports make before break handoff mechanisms Soft and Softer handoff

Break before make only for inter-frequency HO

Soft HO tradeoff required with subscriber capacity

The Need for ATMFundamental Switching types Circuit Switched and Packed Switched

Voice is REAL TIMEDelays not tolerated

Data is Bursty, Asynchronous, Delicate, Irregular, Real time switching not appropriate

SMS S&F (Store and Forward) Switching

CELL SWITCHING ASYNCHRONOUS TRANSPORT MODEor ATM

UMTS supports a wide variety of applications/ services Voice , Data , Video , .

WCDMA GSM Meas. Timing RelationFor smooth interoperation between the systems

WCDMA base station to notify the terminal of the existing GSM frequencies in the area

Handover when lower data rates in GSM when compared to the UMTSmaximum data rates reaching all the way to 2 Mbps

GSM system to indicate the WCDMA spreading codes in the area

Traffic Control AlgorithmsCall Admission Control (CAC)

Prevents air interface overloading

Algorithm placed in RNC. Its task is to admit or deny new subscriber access into the network. Permit is based on current state of air interface and type of service requested by user

It is a single event process

Works on both UL and DL

Load Control

Same criteria as CAC but it is a continuous process through monitoring of the interference

Radio Optimization OverviewCell breathing (Ec/ Io suffers due to noise rise = ROT )

Drive test in busy hour and non-busy hour Comparative coverage

RF Audit Power meter tests

Neighbour List

Scanner drive : Scans 512 scrambling codes (0-511) very fast

OCNS (Orthogonal Channel Noise Simulator)software loads DL

Attenuators can be used toemulate UL loading (Noise Rise)

Iu-b InterfaceAnalogous to GSM Abis interface

NBAP is carried over Iu-bALCAP is carried over Iu-b and Iu-CS interfaces

Bharti planning upto 7 E1 bandwidth per site

Raw Estimation (Radio Capacity) : Transmission bandwidth to radio reverse calculation :

7 2 Mbps = 14 Mbps

14 Mbps 3 sectors 4.5 Mbps

4.5 Mbps/ 100 kbps = 45 simultaneous users

RNC CapacityNortel RNC (Yr. 2003 Brochure)

200 Node B1200 Single carrier WCDMA Cells ( 1 Carrier 1 Sector )3900 Voice Erl. with 12.2 kbps AMR subscribers

Max. number of STM1 (Iub/Iur/Iu) 15 STM16 Sector sites may be considered here

HSPA Family (HSxPA)HSPA evolution is supported by Software Upgrade (e.g. Alcatel-Lucent Node B)

HSDPAAlso dubbed 3.5G , 3G+ or turbo 3GEvolved from and backward compatible with Release 99 WCDMA Systems.Widely deployed -> all new 3G supporting handsets come with HSxPA spec.Down-link speeds of 1.8, 3.6, 7.2 and 14.0 Mbit/s QPSK and 16-QAM (in good radio conditions)

HSUPAThe name HSUPA was created by NokiaUp-link speeds upto 5.76 Mbit/s

HSPA+Upto 42 Mbit/s down-link ------> 84 Mbit/s

3G 3.5G (HSDPA HSUPA) 3.9G (LTE) 4G (LTE Advanced)

LTEE-UTRA (Enhanced UTRA) Node-B eNodeB

Actually 3.9G technology because did not comply fully with IMT Advanced 4G requirements

LTE Advanced is the actual 4G technology

MIMO Antenna technology 22 and 44

Uses OFDM for the downlink

QPSK , 16-QAM and 64-QAM

WCDMA Test and MeasurementDrive TestTEMS Investigation WCDMAAgilent E6474

Test Handsets (UEs)Test UE models usable with Agilent E6474 :Nokia 6720Nokia N85Nokia N97

TEMS use:-Sony Ericsson W760Sony Ericsson C702

Apple iPhone 3G

Field Test

SecurityAuthentication of users through USIM cards

Security includes two procedures : Integrity and Ciphering

Handset (UE) IdentificationMost UMTS handset/ terminal identity types are taken directly from GSM specifications. Mainly below:-

IMEI

IMSI (stored in the USIM)

MSISDN (stored in the USIM)

WCDMA ChipsetsUE Chipset example :-Apple iPhone 3G Infineon SGOLD3 3.5G processor

Node-B Chipset suppliers :-QualcommTexas InstrumentsSamsungAlteraMaxim

Multiuser Detection (MUD)To mitigate Multiple Access Interference (MAI)

Simplest design is based on single user Matched Filter

Wireless Data Network Topologies

P2P

PMP

Mesh

Wireless Area Networks

WAN (Wide Area Network)WWAN e.g. WiMAX

PAN (Personal Area Network)WPAN e.g. BLUETOOTH

LAN (Local Area Network)WLAN e.g. Wi-Fi

CAN (Campus Area Network)WCAN e.g. Wi-Fi

MAN (Metropolitan Area Network)WMAN e.g. Wi-Fi (small) or WiMAX (large)

IP ConceptsTCP ( Transmission Control Protocol)Core protocol of IP Suite. Reliable, ordered delivery of a stream of bytes

UDP ( User Datagram Protocol)Also core protocol of IP Suite. No implicit hand-shaking for reliability, ordering or data integrity Provides an unreliable service Suitable for time-sensitive applications that cannot wait for delayed packets

PPP ( Point-to-Point Protocol)Data link protocol commonly used to establish a direct connection betweentwo networking nodes. Authentication, Encryption privacy and Compression

SNMP ( Simple Network Management Protocol)Used mostly in NMSs to monitor network-attached devices for conditions that warrant administrative attention

DHCP ( Dynamic Host Configuration Protocol)Autoconfiguration protocol eliminates the need for intervention by a network administrator

Mobile IPMobile IP (or IP mobility) is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile device users to move from one network to another while maintaining a permanent IP address.

Care-of-Address

Home Agent

Tunnel

Mobile IP provides an efficient , scalable mechanism for roaming within the Internet.

VoIP over RTTCan work on most packet switched IP based technologies such as EVDO or WiMAX

One reason why Qualcomm stopped EVDV research and development

4G TechnologiesWiMAX

Standard : IEEE 802.16d / IEEE 802.16eMultiple Access : OFDM Modulation : BPSK/ QPSK/ 16-QAM/ 64-QAM (based on link adaptation)Channel bandwidth : 1.75 MHz/ 3 MHz/ 7MHz/ ..14MHz/ 20 MHzDuplexing : TDD (Indian operators)

Base Station (BS) = IDU + ODU Each sector uses BSID & FrequencySubscriber Station (SS) = single unit uses MAC Id and IP Address

4 sector sites generally used to maximize C/I or CINR

WiBRO

is a South Korean variation/ version of WiMAX

LTE Advanced

Standard : IMT AdvancedHuaweiNokia Siemens NetworksAviat NetworksApertoAlvarionProximAirspanMotorolaIDU(blade)BS

WiMAX Radio Link ParametersMeasurements done with reference to BS (UL) or SS (DL)

Channel (center frequency)

Bandwidth

BSID

ulRSSI

dlRSSI

ulCINRLink Adaptation is based on CINR Average

dlCINR

FEC Coding rate

Modulation

TSAT tool developed by Telsima Communications used to log the parameters at SS end.

WiMAX Service Classes

UGSUnsolicited Grant Service

rtPSReal-Time Polling Service

nrtPSNon-Real-Time Polling Service

BEBest Effort

ERT-VRExtended Real-Time Variable Rate

WiMAX Mobility

NomadicThe user is allowed to take a fixed subscriber station and reconnect from a different point of attachment

PortableNomadic access is provided to a portable device , such as a PC card with expectation of a best-effort handover

Simple MobilityThe subscriber may move at speeds upto 50 kmph with brief interruptions (less than 1 sec) during handoff

Full MobilityUpto 120 kmph mobility and seamless handoff (less than 50 ms latency < 1 % packet loss) is supported

Spectrum Flexibility

The channel bandwidth in both WiMAX and LTE is adjustable allowing flexibility in following:-

(1) Allotment of available spectrum by regulatory bodies to multiple competing (new) operators(2) Adjacent channel interference (ACI) mitigation at marginal bandwidth loss(3) Spectrum planning by operator(s) based on bandwidth/ capacity demand

4G Chipsets

Major Chipset types RF Transceiver Baseband Processing

Chipset major vendors

Sequans Communications SQN Series ICs , e.g. , SQNx010 for 16d BS and SS

Intel Link 5350 Chipset

Beceem

Sierra Monolithics (Semtech)

Analog Devices

Maxim Integrated Products

RTT/ RAT InterworkingGSM -3G Interworking already existing

WLAN -3G Interworking Proposals Interworking with Wi-FiApple iphone 3G supports both HSDPA and Wi-Fi

EVDO WiMAX Interworking Proposals in US