302 - CDMA Performance Optimization Using Grayson’s Surveyor

5/20/2018 302 - CDMA Performance Optimization Using Graysons Surveyor

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Course 302 -- CDMA Drive Test & System Optimization Issue 2.0 (March, 2001) Page 1

Course 302

CDMA Performance Optimization

with Grayson CDMA Inspector32

CDMA Performance Optimization

with Grayson CDMA Inspector32


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Outline: Using Surveyor for Optimization

Introduction: Review of CDMA Principles (optional based onportions needed)

CDMA Air Interface Review

CDMA Spread Spectrum Basics

CDMA Signal RF Characteristics

CDMA Spreading Sequences and Code Channels

Forward LinkReverse Link

Call Processing from perspective of Subscriber Handset

Anatomy of a HandsetRF section, digital section, correlators

Operation of the Pilot Searcher

Subscriber Handset Operation, wakeup thru end of call

Messaging Overview


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CDMA Handoff

Pilot Sets: Relationships, number of members, promotion& demotion

Handoff Parameters Handoff Messaging

RF Implications of Handoff Situations

CDMA System Network Architecture and Hardware BasicElements

CDMA Datagathering Introduction

System-side resources, principles, tools: (overview)

Subscriber-side resources, principles, and techniques Handset maintenance mode

Surveyor32 Real-Time and Replay

Analyzer - its role and purpose


4/146Course 302 -- CDMA Drive Test & System Optimization Issue 2.0 (March, 2001) Page 4


Interpreting Real-Time Drive-Tool Displays from Surveyor32

Parameters and values

RF significance of observed values (Ec/Io, TX Gain, TX PO,

RX Level) Seeing the situation through the eyes of the handset

Real-World CDMA Problems and Solutions

Live Examples using Datafiles collected by the class



Course 302

Whats Different about CDMA?

Basic Principles Review

Whats Different about CDMA?

Basic Principles Review



Other Technologies:Recovering the Signal / Avoiding Interference

In conventional radio technologies, thedesired signal must be strong enough tooverride any interference

AMPS, TDMA and GSM depend onphysical distance separation to keepinterference at low levels

Co-channel users are kept at a safedistance by careful frequency planning

Nearby users and cells must use different

frequencies to avoid interference

2

3

4

5 6

7

4

6

4

7 2

7

2

5

3

5

3

6

1

1

1

1

1

1

1

AMPS-TDMA-GSM

Figure of Merit: C/I(carrier/interference ratio)AMPS: +17 dB

TDMA: +14 to 17 dBGSM: +7 to 9 dB.



CDMA: Using A New Dimension

All CDMA users occupy the same frequencyat the same time! Frequency and time arenot used as discriminators, the signals are

hopelessly entangled both in time andfrequency

CDMA operates by using CODING todiscriminate between users

In CDMA systems, the interference comesmainly from other nearby CDMA users

Each users signal is like a small voice in aroaring crowd -- but built using a unique

code that allows the signal to be uniquelydecoded and recovered by the recipient

CDMA

Figure of Merit: C/I(carrier/interference ratio)

AMPS: +17 dBTDMA: +14 to +17 dB

GSM: +7 to 9 dB.CDMA: -10 to -17 dB.CDMA: Eb/No ~+6 dB.



CDMA Uses Code Channels

A CDMA signal uses many chips to convey justone bit of information

Each user has a unique chip pattern, in effect acode channel

To recover a bit, integrate a large number of chipsinterpreted by the users known code pattern

Other users code patterns appear random andadd up to zero in a random self-canceling fashion,thus they dont disturb the bit decoding decisionbeing made with the proper code pattern

The process of going from Symbols into Chips iscalled spreading, since the slow, narrow-bandwidth information is spread so that itoccupies a much larger bandwidth

Building aBuilding aCDMA SignalCDMA Signal

Bitsfrom Users Vocoder

Symbols

Chips

Forward ErrorCorrection

Coding and

Spreading



Spreading, from a Time-Domain point of view

At Originating Site:

Input A: Users Data @19,200 bits/second

Input B: Walsh Code #23@ 1.2288 Mcps

Output: Spreadspectrum signal

At Destination Site:

Input A: Receivedspread spectrum signal

Input B: Walsh Code #23@ 1.2288 Mcps

Output: Users Data @

19,200 bits/second justas originally sent Drawn to actual scale and time alignment

via air interface

XORExclusive-OR

Gate

1

1

Input A: Received Signal

Input B: Spreading Code

Output: Users Original Data

Input A: Users Data

Input B: Spreading Code

Spread Spectrum Signal

XORExclusive-OR

Gate

Originating Site

Destination Site



Spreading: a Frequency-Domain Point of View

Traditional wireless technologies try tosqueeze one signal into a minimumamount of bandwidth, so there can bemany one-user channels

the data rate of the information

dictates how wide a bandwidth thesignal requires; its narrow

CDMA mixes slow information with a fastspreading sequence

this makes a CDMA signal with much

wider bandwidth than the informationalone would require

the extra bandwidth gives a paybackof processing gain which extendscoverage range and improves theradio link performance for users

Multiple users can occupy one CDMAsignal, if each users information is mixedwith a unique, distinct personal spreadingsequence, and then all added together.

Decode the combined signal using

one users spreading sequence, andthat one users signal is recovered

Spread Spectrum Payoff:Processing Gain

Multiple users with diferent codes

Spread SpectrumTRADITIONAL COMMUNICATIONS SYSTEM

SlowInformation

Sent

TX

SlowInformationRecovered

RX

NarrowbandSignal

SPREAD-SPECTRUM SYSTEM

Fast

SpreadingSequence

SlowInformation

Sent

TX

SlowInformationRecovered

RX

Fast

SpreadingSequence

Wideband

Signal



CDMA: is it really magic, or just a card trick?

if 1 =if 0 =

1

Analog

SummingUsers

QPSK RF

DemodulatedReceived

CDMA Signal

Despreading Sequence(Locally Generated, =0)

matches

opposite

Decision:

Matches!( = 0 )

TimeIntegration

1

Opposite( =1)

+10

-26

Received energy: Correlation

-16

BTS

This figure illustrates the basic technique of

CDMA signal generation and recovery.The actual coding process used in IS-95 CDMA includesa few additional layers, as well see in following slides.



The Concept of Orthogonality

Each users signal must bebuilt using a unique

spreading sequence, if we areto recover it individually

if users spreadingsequences arent unique,

all users signals will behopelessly jumbledtogether andunrecoverable

This uniqueness is calledOrthogonality

The spreading sequences weuse in CDMA are orthogonal

Comparing Signals:Are they Orthogonal?

Two signals are orthogonal if theircorresponding bits match in half thepositions, and dont match in half thepositionsOne way to check for orthogonality is

to add the two signals in binary form(modulo 2).If the signals are orthogonal, the sumwill contain exactly as many ones aszeroes..

0 1 1 0 1 1 1 0

0 0 1 0 1 1 0 0

0 1 0 0 0 0 1 0=

+

Signal A

Signal B

Binary Sum

Not these two signals!



Spreading: Whatever we encode, we can decode

Sender combines data with a fast spreading sequence, transmits

spread data stream Receiver intercepts the stream, uses same spreading sequence

to extract original data

If this basic idea makes sense, youre ready to understand the fullprocess used in commercial CDMA

ORIGINATING SITE DESTINATION

SpreadingSequence

SpreadingSequence

InputData RecoveredData

Spread Data Stream



Shipping and Receiving via CDMA

Whether in package shipping and receiving, or in CDMA signals,

packaging methods are extremely important! Cargo is placed inside nested containers. Each container has

some special purpose -- for example, the disk is readable by aPC, the mailer keeps the disk from getting bent or damaged, and

the shipping envelope can be addressed to the final destination The shipper packs in a certain order, and the recipient unpacks

in the reverse order

For CDMA signals, the containers for our shipment are three

different kinds of spreading codes, and each one is used for aspecific purpose

Fed

Ex

Data Mailer

Fed

Ex

DataMailer

Shipping Receiving


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CDMAs Three Nested Spreading Sequences

CDMA signals are built up using three different types of spreadingsequences -- this makes each signal unique and very rugged/robust

These sequences are easy to generate, in a base station and in a handset

Using these sequences, Whatever we encode, we can decode

Next step is to meet these sequences, see their special properties

what are their functions on the forward link (base station to mobile) ?

what are their functions on the reverse link (mobile to base station) ?

Dont worry about each sequence exact purpose yet; these are different onthe forward and reverse links; well see their jobs after the introductions

Spreading

SequenceA

Spreading

SequenceB

Spreading

SequenceC

Spreading

SequenceC

Spreading

SequenceB

Spreading

SequenceA

InputData

X

RecoveredData

X

X+A X+A+B X+A+B+C X+A+B X+A

Spread-Spectrum Chip StreamsORIGINATING SITE DESTINATION


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Sneak Preview of the other CDMA Sequences

The other two CDMA sequencesare generated in shift registers

An ordinary shift register is no fun,

sequence length = register length

A Tapped shift register generatesa wild, self-mutating sequence2N-1 chips long (N=register length)

Such sequences match ifcompared in step (no-brainer,any sequence matches itself)

Such sequences appearapproximately orthogonal ifcompared with themselves notexactly matched in time

false correlation typically ~1%

A Tapped, Summing Shift Register

Sequence repeats every 2N

-1 chips,where N is number of cells in register

An Ordinary Shift Register

Sequence repeats every Nchips,where N is number of cells in register

A Special Characteristic of SequencesGenerated in Tapped Shift Registers

Compared In-Step: Matches Itself

Complete Correlation: All 0sSum:

Self, in sync:

Sequence:

Compared Shifted: Little Correlation

Practically Orthogonal: Half 1s, Half 0sSum:

Self, Shifted:

Sequence:

M t th CDMA S di S


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Meet another CDMA Spreading Sequence:The PN Short Code

The PN Short Code consists of twoPN Sequences, I (in-phase) and Q(quadrature), each 32,768 chips long

Theyre generated in similar butdifferently-tapped 15-bit-long shiftregisters

I&Q always used simultaneously,modulating the two phase axesof a QPSK RF modulator

The PN Short Code

IQ

32,768 chips long

26-2/3 ms.(75 repetitions in 2 sec.)

CDMA QPSK Phase ModulatorUsing I and Q PN Sequences

I-sequence

Q-sequence

cos t

sin t

chip

input

QPSK-modulatedRF

Output

*

* In BTS, I and Q are used in-phase.In handset, Q is delayed 1/2 chip toavoid zero-amplitude crossings which

would require a linear power amplifier

Acronym: PN = Pseudorandom Noise

Meet another CDMA Spreading Sequence:


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Meet another CDMA Spreading Sequence:The PN Long Code

Generated in a 42-bit register, the PN Long code is more than 40 dayslong (~4x1013 chips) -- too big to store in ROM in a handset, so itsgenerated chip-by-chip using the scheme shown above

Each handset codes its signal with the PN Long Code, but at a uniqueoffset computed using its ESN (32 bits) and 10 bits set by the system

this is called the Public Long Code Mask; produces unique shift

private long code masks are available for enhanced privacy

Integrated over a period even as short as 64 chips, phones with differentPN long code offsets will appear practically orthogonal

Long CodeState Register(@ 1.2288 MCPS)

PublicLong Code Mask

(STATIC)

User Long CodeSequence

(@1.2288 MCPS)

1 1 0 0 0 1 1 0 0 0 Ph o n e s ESN , Pe rmu t e d+

=SUMModulo-2 Addition


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Putting it All Together: the CDMA Channels

All three spreading codes are used on both the forward and reverse links Forward Channel: Each Sector has a unique PN Short Code offset, each userin that sector has a personal Walsh Code

long code is used incidentally for scrambling Reverse Channel: Each phone has a unique PN Long Code offset, different

from every other phone in the world Incidentally, Walsh Codes used as symbols, short code for modulation

BTSPN LONG CODEat users offset

FORWARD CHANNEL

REVERSE CHANNEL

All WALSH CODES

used as tokensfor user bits,makes signalvery robust

scrambled + WALSH CODE




PN SHORT CODE

at unique PN offset

of BTS sector

SHORT PN:

used at offset 0,gives OQPSKmodulation

by Long Code


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How a BTS Builds the Forward Code Channels

BSC orAccessManager

BTS (1 sector)

FECWalsh #1

Sync FECWalsh #32

FECWalsh #0

FECWalsh #12

FECWalsh #27

FECWalsh #44

Pilot

Paging

Vocoder

Vocoder

Vocoder

Vocoder

more more

Short PN CodePN Offset 246

Trans-mitter,

Sector X

Switch

more

a Channel Element

A Forward Channelis identified by:

its CDMA RFcarrier Frequency

the unique Short

Code PN Offset ofthe sector

the unique WalshCode of the user

FECWalsh #23

Q

I

x

x

+

cos t

sin t

I Q


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Functions of the CDMA Forward Channels

PILOT: WALSH CODE 0 The Pilot is a structural beacon which

does not contain a character stream. It is atiming source used in system acquisitionand as a measurement device during

handoffs SYNC: WALSH CODE 32

This carries a data stream of systemidentification and parameter informationused by mobiles during system acquisition

PAGING: WALSH CODES 1 up to 7 There can be from one to seven paging

channels as determined by capacity needs.They carry pages, system parametersinformation, and call setup orders

TRAFFIC: any remaining WALSH codes The traffic channels are assigned to

individual users to carry call traffic. Allremaining Walsh codes are available,subject to overall capacity limited by noise

Pilot Walsh 0

Walsh 19

Paging Walsh 1

Walsh 6

Walsh 11

Walsh 20

Sync Walsh 32

Walsh 42

Walsh 37

Walsh 41

Walsh 56

Walsh 60

Walsh 55


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Code Channels in the Reverse Direction

BSC(Access

Manager)

Switch BTS (1 sector)

Channel Element

Access Channels

Vocoder

Vocoder

Vocoder

Vocoder

more more

Receiver,

Sector X

A Reverse Channel is identified by:

its CDMA RF carrier Frequency

the unique Long Code PN Offsetof the individual handset

Channel Element

Channel Element

Channel Element

Channel Element

Long Code Gen

Long Code Gen

Long Code Gen

Long Code Gen

Long Code Gen

more

Long

Codeoffset LongCodeoffset Long

Codeoffset

Long

Codeoffset

LongCode

offset

LongCodeoffset

F ti f th CDMA R Ch l


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Functions of the CDMA Reverse Channels

There are two types of CDMA Reverse Channels:

TRAFFIC CHANNELS are used by individual usersduring their actual calls to transmit traffic to the BTS

a reverse traffic channel is defined by a user-specific public or private Long Code mask

there are as many reverse Traffic Channels asthere are CDMA phones in the world

ACCESS CHANNELS are used by mobiles not yet in acall to transmit registration requests, call setuprequests, page responses, order responses, and othersignaling information

an access channel is defined by a public longcode mask specific to the BTS sector

Access channels are paired with PagingChannels. There can be up to 32 accesschannels per paging channel

REG

1-800

242

4444

BTS


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Basic CDMA Network Architecture

Access Manageror (C)BSC

Switch BTS

Ch. Card

Vocoders

Selectors

CDSU

CDSU

DTCs

TxcvrB

RFFEB

GPS

PSTN

DISCO 1

DS0 in T1Packets Chips

RFChannelElementVocoder


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Variable Rate Vocoding & Multiplexing

Vocoders compress speech, reduce bitrate

CDMA uses a superior Variable Rate

Vocoder full rate during speech

low rates in speech pauses

increased capacity more natural sound

Voice, signaling, and user secondarydata may be mixed in CDMA frames

The protocols governing the mixture arethe Multiplex Options; 1 = 8K, 2 = 13K

The content of the primary traffic bits aredetermined by Service Options which themobile and system negotiate

DSP QCELP VOCODER

Codebook

PitchFilter

FormantFilter

Coded Result Feed-back

20ms Sample

Frame Sizesbits

Full Rate Frame

1/2 Rate Frame

1/4 Rt.

1/836

72

144

288

Frame Contents: can be a mixture of

Voice Signaling Secondary


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Forward Power Control

The BTS continually reduces the strength of each users forwardbaseband chip stream

When a particular handset sees errors on the forward link, itrequests more energy

The complainers chip stream gets a quick boost; afterward,continues to diminish

ForwardRF

BSC BTS (1 sector)

Sync

Pilot

Paging

more

Short PN

Trans-mitter,

Sector X

I QUser 1User 2

User 3Vocoder/Selector

Help!

R P C l


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Reverse Power Control

Three methods work in tandem to equalize all handset signal levelsat the BTS

Reverse Open Loop: handset adjusts power up or down basedon received BTS signal (AGC)

Reverse ClosedLoop: Is handset too strong? BTS tells up ordown 1 dB 800 times/second

Reverse OuterLoop: BSC has FER trouble hearing handset?BSC adjusts BTS setpoint

RX RF

TX RF Digital

BTSBSC

SetpointBad FER?Raise Setpoint

Stronger thansetpoint?

ReverseRF

800 bits per second

Occasionally,as needed

Handset

OpenLoop

Closed

Loop

Digital

Wh t I H d t?


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Whats In a Handset?

ReceiverRF SectionIF, Detector

TransmitterRF Section

Vocoder

DigitalRake Receiver

Traffic Correlator

PN xxx Walsh xx

Traffic CorrelatorPN xxx Walsh xxTraffic Correlator

PN xxx Walsh xx

Pilot Searcher

PN xxx Walsh 0

ViterbiDecoder

CPUDuplexer

TransmitterDigital Section

Long Code Gen.

Open

L

oop

Transmit Gain Adjust

Messages

Messages

Audio

Audio

Packets

Symbols

SymbolsChips

RF

RF

AGC

Th R k R i


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The Rake Receiver

Every frame, handset uses combined outputs of the three trafficcorrelators (rake fingers)

Each finger can independently recover a particular PN offset andWalsh code

Fingers can be targeted on delayed multipath reflections, or even ondifferent BTSs

Searcher continuously checks pilots

Handset Rake Receiver

RF

PN Walsh

PN Walsh

PN Walsh

SearcherPN W=0

Voice,Data,

Messages

Pilot Ec/Io

BTS

BTS

CDMA S ft H d ff M h i


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CDMA Soft Handoff Mechanics

CDMA soft handoff is driven by the handset

Handset continuously checks available pilots

Handset tells system pilots it currently sees System assigns sectors (up to 6 max.), tells handset

Handset assigns its fingers accordingly

All messages sent by dim-and-burst, no muting! Each end of the link chooses what works best, on a frame-by-frame

basis!

Users are totally unaware of handoff


RF

PN Walsh

PN Walsh

PN Walsh

Searcher

PN W=0

Voice,Data,

Messages

Pilot Ec

/Io

BTS

BSCSwitch

BTS

Sel.

Softer Handoff


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Softer Handoff

Each BTS sector has unique PN offset & pilot

Handset will ask for whatever pilots it wants

If multiple sectors of one BTS simultaneously serve a handset, this iscalled Softer Handoff

Handset is unaware, but softer handoff occurs in BTS in a singlechannel element

Handset can even use combination soft-softer handoff on multipleBTS & sectors


RF

PN Walsh

PN Walsh

PN Walsh

Searcher

PN W=0

Voice,Data,

Messages

Pilot Ec

/Io

BTS

BSCSwitch

Sel.


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Course 302

CDMA Messaging and Call FlowCDMA Messaging and Call Flow

Messaging as an Investigative Resource:


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Messaging as an Investigative Resource:Why did a Flight Crash? Why did a Call Drop?

Layer-3 Messaging between systemand phone during a call is much likein-flight voice messaging betweenair traffic controllers and pilots.

When a call drops or a flight goes

down, intense investigation of themessaging will often identify thecause of the problem.

The Cockpit Voice Recorder givesextremely valuable information. The

CDMA equivalent is a log file fromdrive-test equipment. It can answer:

What was the call state at thetime of the crash? (handoffs,primary PN, mobile parameters)

Was messaging reliable? Were there any pending

messages not acknowledged orrequests not yet implementedon either side?

Was either link under stress?

CDMA Messaging is much likeAir Traffic Control messaging

BTS

Sources of CDMA Data and Tools for Processing


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g

CDMA optimization data flows from three places: Switch, CDMA peripherals and base stations, and the Handset

Various software and hardware tools are available for collectionand analysis of each of these streams of data

Data contains messages and various indicators of RF performance

Access Mgr./BSC-BSMSwitch BTS

CDSU DISCO

Ch. Card ACC

TFU1

GPSR

CDSU

CDSU

DISCO 1

DISCO 2

SBSVocoders

Selectors

CDSU

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

Txcvr A

Txcvr B

Txcvr C

RFFE A

RFFE B

RFFE C

TFU1

GPSR

IOC

BSM

Data AnalysisPost-Processing

Tools

IS-95/J Std 8 Messages

IS-95/J Std 8Messages

NOIS Messages

QC-Specific Messages

Switch OMs,

pegs, logs

Mobile DataPost-Processing

Tools

Mobile DataCapture ToolsSelector

Logs

NMIS Messages

HandsetMessages

ExternalAnalysis

Tools

PC-based

PC-based

Unix-based,PC-basedVarious

CDMA NETWORK EQUIPMENT HANDSET

Structure of CDMA Messages


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Structure of CDMA Messages

CDMA messages on both forwardand reverse links are normally sentvia dim-and-burst

Messages include many fields of

binary data The first byte of each message

identifies message type to allow therecipient to parse the contents

To ensure no messages aremissed, all CDMA messages bearserial numbers and importantmessages contain a bit requestingacknowledgment

Messages not promptlyacknowledged are retransmittedseveral times, after which thesender may release the call

Surveyor parses all messages forreview and analysis

MSG_TYPE (00000110)

ACK_SEQ

MSG_SEQ

ACK_REQ

ENCRYPTION

ERRORS_DETECTED

POWER_MEAS_FRAMES

LAST_HDM_SEQ

NUM_PILOTS

PILOT_STRENGTH

RESERVED (0s)

8

3

3

1

2

5

10

2

4

6

0-7

NUM_PILOTS occurrences of this field:

Field Length

(in bits)

EXAMPLE:

A POWER MEASUREMENT

REPORT MESSAGE

Messages In Acquisition and Idle States


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g q

Sync Channel

Sync Channel Msg

Pilot Channel

No Messages

Paging Channel

Access Parameters Msg

System Parameters Msg

CDMA Channel List Msg

Extended SystemParameters Msg

Extended NeighborList Msg

Global ServiceRedirection Msg

Order MsgBase Station Acknowledgment

Lock until Power-Cycled Maintenance required

many others..

AuthenticationChallenge Msg

Status Request Msg

Feature Notification Msg

TMSI Assignment Msg

Channel AssignmentMsg

SSD Update Msg

Service Redirection Msg

General Page Msg

Null Msg Data Burst Msg

Access Channel

Registration Msg

Order Msg Mobile Station Acknowldgment

Long Code Transition Request SSD Update Confirmation

many others..

Origination Msg

Page Response Msg

Authentication ChallengeResponse Msg

Status Response Msg

TMSI AssignmentCompletion Message

Data Burst Msg

BTS

Messages During a Call: Conversation State


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Messages During a Call: Conversation State

Reverse Traffic Channel

Order Message

Mobile Sta. Acknowledgment

Long Code TransitionRequest

SSD Update Confirmation

Connect

Authentication ChallengeResponse Msg

Flash WithInformation Msg

Data Burst Message

Pilot StrengthMeasurement Msg

Power MeasurementReport Msg

Send Burst DTMF Msg

OriginationContinuation Msg

Handoff Completion Msg

Parameters ResponseMessage

Service Request Msg

Service Response Msg

Service ConnectCompletion Message

Service Option ControlMessage

Status Response Msg

TMSI AssignmentCompletion Message

Forward Traffic Channel

Order Msg Base Station Acknowledgment

Base Station ChallengeConfirmation

Message Encryption Mode

AuthenticationChallenge Msg

Alert WithInformation Msg

Data Burst Msg

Analog HandoffDirection Msg

In-Traffic SystemParameters Msg

Neighbor ListUpdate Msg

Send Burst DTMF Msg

Power ControlParameters Msg.

Retrieve Parameters Msg

Set Parameters Msg

SSD Update Msg

Flash WithInformation Msg

Mobile StationRegistered Msg

Status Request Msg

Extended HandoffDirection Msg

Service Request Msg

Service Response Msg

Service Connect Msg

Service OptionControl Msg

TMSI Assignment Msg


39/146


Adventures in Call Processing5 Minutes in the Life of a CDMA HandsetAdventures in Call Processing

5 Minutes in the Life of a CDMA Handset

30Seconds

(thatsall

wevego

ttimeto

doinone

day!)

Our Call Processing Adventures


40/146


Our Call Processing Adventures

Lets Acquire the System!

Lets do an Idle Mode Handoff!

Lets Register!

Lets Receive an Incoming Call!

Lets Make an Outgoing Call!

Lets End a Call!

Lets Receive Notification of a Voice Message! Lets Do a Handoff!


41/146


Lets Acquire the System!Lets Acquire the System!

CDMA Call Processing

Find a Frequency with a CDMA RF Signal


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Find a Frequency with a CDMA RF Signal

Mobile scans forward link frequencies:

(Cellular or PCS, depending on model)

History ListPreferred Roaming List

until a CDMA signal is found.NO CDMA?! Go to AMPS,

or to a power-saving standby mode

HISTORY

LIST

Last-used:

Freq/SID x

Freq/SID y

Freq/SID z

Freq/SID t

Freq/SID u

etc.

FREQUENCY LISTS:

PREFERRED

ROAMING

LIST

Freq/SID 1

Freq/SID 2

Freq/SID 3

Freq/SID 4

Freq/SID 5etc.

Forward Link Frequencies(Base Station Transmit)

A D B E F Cunlic.

data

unlic.

voiceA D B E F C

1850MHz. 1910MHz. 1990 MHz.1930MHz.

1900 MHz. PCS Spectrum

824 MHz. 835 845 870 880 894

869

849

846.5825

890

891.5

Paging, ESMR, etc.

A B A B

800 MHz. Cellular Spectrum

Reverse Link Frequencies(Mobile Transmit)

Find Strongest Pilot, Read Sync Channel


43/146


g , y

Rake Fingers

Reference PN

Active Pilot

Ec/Io

0

032K

512Chips

PN

1. Pilot SearcherScans the Entire Range of PNs

All PN Offsets

0

-20

98/05/24 23:14:09.817 [SCH]

Sync Channel Message

MSG_LENGTH = 208 bitsMSG_TYPE = Sync Channel Message

P_REV = 3

MIN_P_REV = 2

SID = 179

NID = 0

PILOT_PN = 168 Offset Index

LC_STATE = 0x0348D60E013

SYS_TIME = 98/05/24 23:14:10.160

LP_SEC = 12

LTM_OFF = -300 minutes

DAYLT = 0

PRAT = 9600 bps

RESERVED = 1

2. Put Rake finger(s) on strongest

available PN, decode Walsh 32,

and read Sync Channel Message

SYNC CHANNEL MESSAGE


RF x

LOSrch PN??? W0

F1 PN168 W32

F2 PN168 W32

F3 PN168 W32

The Configuration Messages


44/146


g g

After reading the Sync Channel, the mobile is now capable ofreading the Paging Channel, which now monitors constantly

Before it is allowed to transmit or operate on this system, themobile must collect a complete set of configuration messages

Collection is a short process -- all configuration messages arerepeated on the paging channel every 1.28 seconds

The configuration messages contain sequence numbers so themobile can recognize if any of the messages have been freshlyupdated as it continues to monitor the paging channel

Access parameters message sequence number

Configuration message sequence number

If a mobile notices a changed sequence number, or if 600seconds passes since the last time these messages were read,

the mobile reads all of them again

Go to Paging Channel, Get Configured


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g g , g

Rake Fingers

Reference PN

Active Pilot

Ec/Io

0

032K

512Chips

PN

All PN Offsets0

-20

Keep Rake finger(s) on strongest

available PN, decode Walsh 1,

and monitor the Paging Channel

Read theConfiguration Messages

Access Parameters Msg

System Parameters Msg

CDMA Channel List Msg

Extended SystemParameters Msg (*opt.)

(Extended*) NeighborList Msg

Global ServiceRedirection Msg (*opt.)

Now were ready to operate!!


RF x

LOSrch PN??? W0

F1 PN168 W01

F2 PN168 W01

F3 PN168 W01

Two Very Important Configuration Messages


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y p g g

98/05/24 23:14:10.427 [PCH]MSG_LENGTH = 184 bitsMSG_TYPE = Access Parameters MessagePILOT_PN = 168 Offset Index

ACC_MSG_SEQ = 27ACC_CHAN = 1 channelNOM_PWR = 0 dBINIT_PWR = 0 dBPWR_STEP = 4 DbNUM_STEP = 5 Access Probes MaximumMAX_CAP_SZ = 4 Access Channel Frames MaximumPAM_SZ = 3 Access Channel FramesPersist Val for Acc Overload Classes 0-9 = 0Persist Val for Acc Overload Class 10 = 0

Persist Val for Acc Overload Class 11 = 0Persist Val for Acc Overload Class 12 = 0Persist Val for Acc Overload Class 13 = 0Persist Val for Acc Overload Class 14 = 0Persist Val for Acc Overload Class 15 = 0Persistance Modifier for Msg Tx = 1Persistance Modifier for Reg = 1Probe Randomization = 15 PN chips

Acknowledgement Timeout = 320 msProbe Backoff Range = 4 Slots MaximumProbe Sequence Backoff Range = 4 Slots Max.Max # Probe Seq for Requests = 2 SequencesMax # Probe Seq for Responses = 2 SequencesAuthentication Mode = 1Random Challenge Value = Field OmittedReserved Bits = 99

ACCESS PARAMETERS MESSAGE 98/05/24 23:14:11.126 [PCH] System Parameter MessageMSG_LENGTH = 264 bitsMSG_TYPE = System Parameters MessagePILOT_PN = 168 Offset IndexCONFIG_MSG_SEQ = 0SID = 179 NID = 0REG_ZONE = 0 TOTAL_ZONES = 0 ZONE_TIMER = 60 minMULT_SIDS = 0 MULT_NID = 0 BASE_ID = 8710BASE_CLASS = Public MacrocellularPAGE_CHAN = 1 channelMAX_SLOT_CYCLE_INDEX = 0HOME_REG = 0 FOR_SID_REG = 0 FOR_NID_REG = 1POWER_UP_REG = 0 POWER_DOWN_REG = 0PARAMETER_REG = 1 REG_PRD = 0.08 secBASE_LAT = 00D00'00.00N BASE_LONG = 000D00'00.00EREG_DIST = 0SRCH_WIN_A = 40 PN chipsSRCH_WIN_N = 80 PN chipsSRCH_WIN_R = 4 PN chipsNGHBR_MAX_AGE = 0PWR_REP_THRESH = 2 frames

PWR_REP_FRAMES = 56 framesPWR_THRESH_ENABLE = 1PWR_PERIOD_ENABLE = 0PWR_REP_DELAY = 20 framesRESCAN = 0T_ADD = -13.0 dB T_DROP = -15.0 dB T_COMP = 2.5 dBT_TDROP = 4 secEXT_SYS_PARAMETER = 1

RESERVED = 0GLOBAL_REDIRECT = 0

SYSTEM PARAMETERS MESSAGE

Four Additional Configuration Messages


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98/05/24 23:14:10.946 [PCH]Extended System Parameters MessageMSG_LENGTH = 104 bits

MSG_TYPE = Extended System Parameters MessagePILOT_PN = 168 Offset IndexCONFIG_MSG_SEQ = 0 RESERVED = 0PREF_MSID_TYPE = IMSI and ESNMCC = 000 IMSI_11_12 = 00RESERVED_LEN = 8 bitsRESERVED_OCTETS = 0x00BCAST_INDEX = 0

RESERVED = 0

EXTENDED SYSTEM PARAMETERS

98/05/17 24:21.566 Paging Channel: Global Service RedirectionPILOT_PN: 168, MSG_TYPE: 96, CONFIG_MSG_SEQ: 0Redirected access overload classes: { 0, 1 },RETURN_IF_FAIL: 0,DELETE_TMSI: 0,Redirection to an analog system:EXPECTED_SID = 0Do not ignore CDMA Available indicator on the redirected analogsystem

Attempt service on either System A or B with the custom systemselection process

GLOBAL SERVICE REDIRECTION

98/05/24 23:14:11.486 [PCH] Neighbor List Message

MSG_LENGTH = 216 bitsMSG_TYPE = Neighbor List MessagePILOT_PN = 168 Offset IndexCONFIG_MSG_SEQ = 0PILOT_INC = 4 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 220 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 52 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 500 Offset Index

NGHBR_CONFIG = 0 NGHBR_PN = 8 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 176 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 304 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 136 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 384 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 216 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 68 Offset IndexNGHBR_CONFIG = 0 NGHBR_PN = 328 Offset Index

NGHBR_CONFIG = 0 NGHBR_PN = 112 Offset IndexRESERVED = 0

NEIGHBOR LIST

98/05/24 23:14:10.786 [PCH] CDMA Channel List MessageMSG_LENGTH = 72 bitsMSG_TYPE = CDMA Channel List Message

PILOT_PN = 168 Offset IndexCONFIG_MSG_SEQ = 0CDMA_FREQ = 283RESERVED = Field Omitted

CDMA CHANNEL LIST MESSAGE


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Lets do anIdle Mode Handoff!

Lets do an

Idle Mode Handoff!


Idle Mode Handoff


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An idle mobile always demodulates the best available signal

In idle mode, it isnt possible to do soft handoff and listen tomultiple sectors or base stations at the same time -- the pagingchannel information stream is different on each sector, not

synchronous -- just as the TV news programs on differentnetworks are not in sync word-by-word if viewed together

Since a mobile cant combine signals, the mobile must switchquickly, always enjoying the best available signal

The mobiles pilot searcher is constantly checking neighbor pilots

If the searcher notices a better signal, the mobile continues on thecurrent paging channel until the end of the current superframe,then instantly switches to the paging channel of the new signal

The system doesnt know the mobile did this! (Does NBCsTom Brokaw know you just switched your TV to CNN?)

On the new paging channel, if the mobile learns that registration is

required, it re-registers on the new sector

Idle Mode on the Paging Channel:Meet the Neighbors, track the Strongest Pilot


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Meet the Neighbors, track the Strongest Pilot

Ec/Io

All PN Offsets

0

032K

512Chips

PN

0

-20

Neighbor Set

The phones pilot searcher constantly checksthe pilots listed in the Neighbor List Message

If the searcher ever notices a neighbor pilot substantially stronger than

the current reference pilot, it becomes the new reference pilot

and the phone switches over to its paging channel on the next superframe.

This is called an idle mode handoff.

Rake Fingers

Reference PN

Active Pilot

SRCH_WIN_A

SRCH_WIN_N

Mobile Rake RX

Srch PN??? W0

F1 PN168 W01

F2 PN168 W01

F3 PN168 W01

Phone Operation on the Access Channel


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A sectors Paging Channel announces 1(typ) to 32 (max) Access Channels: PNLong Code offsets for mobiles to use ifaccessing the system.

For mobiles sending Registration,Origination, Page Responses

Base Station always listening! On the access channel, phones are not

yet under BTS closed-loop power control! Phones access the BTS by probing at

power levels determined by receive power

and an open loop formula If probe not acknowledged by BTS

within ACC_TMO (~400 mS.), phonewill wait a random time (~200 mS)then probe again, stronger by PI db.

There can be 15 max. (typ. 5) probesin a sequence and 15 max. (typ. 2)sequences in an access attempt

most attempts succeed on first probe! The Access Parameters message on the

paging channel announces values of all

related parameters

ACCESS

RV TFC

BTS

Channel Assnmt. Msg.

Origination Msg

Base Sta. Acknlgmt. Order

TFC frames of 000s

TFC preamble of 000s


Mobile Sta. Ackngmt. Order

Service Connect Msg.

Svc. Connect Complete Msg


Call is Established!

MSProbing

PAGING

FW TFC

PAGING

RV TFC

FW TFC

RV TFC

FW TFC

FW TFC

A Successful Access Attempt

a Probe Sequencean Access Attempt

Success!

an Access Probe


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Lets Register!Lets Register!


Registration


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Registration is the process by which an idle mobile lets the systemknow its awake and available for incoming calls

this allows the system to inform the mobiles home switch of

the mobiles current location, so that incoming calls can bedelivered

registration also allows the system to intelligently page themobile only in the area where the mobile is currently located,

thereby eliminating useless congestion on the paging channelsin other areas of the system

There are many different conditions that could trigger an obligationfor the mobile to register

there are flags in the System Parameters Message which tellthe mobile when it must register on the current system

An Actual Registration


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16:18:27.144 Access Channel: RegistrationACK_SEQ: 7 MSG_SEQ: 1 ACK_REQ: 1 VALID_ACK: 0ACK_TYPE: 0MSID_TYPE: 3, ESN: [0x 01 99 0d fc]

MFR 1, Reserved 38, Serial Number 69116,IMSI: (Class: 0, Class_0_type: 1) [0x 01 8d 31 74 29 36]00-416-575-0421

AUTH_MODE: 0REG_TYPE: Timer-basedSLOT_CYCLE_INDEX: 2MOB_P_REV: 1EXT_SCM: 1

SLOTTED_MODE: 1MOB_TERM: 1

REGISTRATION MESSAGE

18:26.826 [PCH] System Parameters MessagePilot_PN: 32CONFIG_MSG_SEQ: 14 SID: 16420 NID: 0,REG_ZONE: 0 TOTAL_ZONES: 0 Zone timer length (min): 1MULT_SIDS: 0 MULT_NIDS: 0BASE_ID: 1618 BASE_CLASS: ReservedPAG_CHAN: 1 MAX_SLOT_CYCLE_INDEX: 2HOME_REG: 1 FOR_SID_REG: 1 FOR_NID_REG: 1,

POWER_UP_REG: 1 POWER_DOWN_REG: 1

PARAMETER_REG: 1 Registration period (sec): 54

Base station 00000.00 Lon., 00000.00 Lat. REG_DIST: 0SRCH_WIN_A (PN chips): 28 SRCH_WIN_N (PN chips): 100,SRCH_WIN_R (PN chips): 130 NGHBR_MAX_AGE: 2PWR_REP_THRESH: 2 PWR_REP_FRAMES (frames): 15PWR_THRESH_ENABLE: 1 PWR_PERIOD_ENABLE: 0,PWR_REP_DELAY: 1 (4 frames) RESCAN: 0,T_ADD: -14.0dB T_DROP: -16.0dB T_COMP: 2.5dB,T_TDROP: 4sEXT_SYS_PARAMETER: 1EXT_NGHBR_LIST: 1GLOBAL_REDIRECT: 0

SYSTEM PARAMETERS MESSAGE

16:18:27.506 Paging Channel: OrderACK_SEQ: 1 MSG_SEQ: 0 ACK_REQ: 0 VALID_ACK: 1MSID_TYPE: 2 IMSI: (Class: 0, Class_0_type: 3)[0x 02 47 8d 31 74 29 36] (302) 00-416-575-0421Order type: Base Station Acknowledgement Order

BASE STATION ACKNOWLEDGMENT

The System Parameters Message tellsall mobiles when they should register.

This mobile notices that it is obligated toregister, so it transmits a Registration

Message.

The base station confirms that themobiles registration message was

received. Were officially registered!


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Lets Receivean incoming Call!

Lets Receive

an incoming Call!


Receiving an Incoming Call


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All idle mobiles monitor the paging channel to receive incomingcalls.

When an incoming call appears, the paging channel notifies themobile in a General Page Message.

A mobile which has been paged sends a Page ResponseMessage on the access channel.

The system sets up a traffic channel for the call, then notifies themobile to use it with a Channel Assignment Message.

The mobile and the base station notice each others traffic channelsignals and confirm their presence by exchangingacknowledgment messages.

The base station and the mobile negotiate what type of call this willbe -- I.e., 13k voice, etc.

The mobile is told to ring and given a calling line ID to display.

When the human user presses the send button, the audio path is

completed and the call proceeds.

An Actual Page and Page Response


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98/05/24 23:14:46.425 [ACH] Page Response MessageMSG_LENGTH = 216 bitsMSG_TYPE = Page Response MessageACK_SEQ = 1 MSG_SEQ = 2 ACK_REQ = 1VALID_ACK = 1 ACK_TYPE = 2MSID_TYPE = IMSI and ESN MSID_LEN = 9 octetsESN = 0xD30E415C IMSI_CLASS = 0IMSI_CLASS_0_TYPE = 0 RESERVED = 0

IMSI_S = 6153300644AUTH_MODE = 1AUTHR = 0x307B5 RANDC = 0xC6 COUNT = 0MOB_TERM = 1 SLOT_CYCLE_INDEX = 0MOB_P_REV = 3 SCM = 106REQUEST_MODE = Either Wide Analog or CDMA OnlySERVICE_OPTION = 32768 PM = 0NAR_AN_CAP = 0 RESERVED = 0

PAGE RESPONSE MESSAGE

98/05/24 23:14:46.127 [PCH] General Page MessageMSG_LENGTH = 128 bitsMSG_TYPE = General Page MessageCONFIG_MSG_SEQ = 1 ACC_MSG_SEQ = 20CLASS_0_DONE = 1CLASS_1_DONE = 1 RESERVED = 0BROADCAST_DONE = 1 RESERVED = 0ADD_LENGTH = 0 bits ADD_PFIELD = Field OmittedPAGE_CLASS = 0 PAGE_SUBCLASS = 0MSG_SEQ = 1

IMSI_S = 6153300644

SPECIAL_SERVICE = 1SERVICE_OPTION = 32768RESERVED = Field Omitted

GENERAL PAGE MESSAGE

98/05/24 23:14:46.768 [PCH] Order Message

MSG_LENGTH = 112 bitsMSG_TYPE = Order MessageACK_SEQ = 2 MSG_SEQ = 0 ACK_REQ = 0VALID_ACK = 1ADDR_TYPE = IMSI ADDR_LEN = 40 bitsIMSI_CLASS = 0 IMSI_CLASS_0_TYPE = 0 RESERVED = 0IMSI_S = 6153300644ORDER = Base Station Acknowledgement Order

ADD_RECORD_LEN = 0 bitsOrder-Specific Fields = Field Omitted RESERVED = 0


The system pages the mobile,615-330-0644.

The base station confirms that the mobilespage response was received. Now the

mobile is waiting for channel assignment,expecting a response within 12 seconds.

The mobile responds to the page.

Channel Assignment andTraffic Channel Confirmation


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18:14:47.598 Reverse Traffic Channel: OrderACK_SEQ: 0 MSG_SEQ: 0 ACK_REQ: 0ENCRYPTION: 0Mobile Station Acknowledgement Order

MOBILE STATION ACKNOWLEDGMENT

18:14:47.027 Paging Channel: Channel AssignmentACK_SEQ: 2 MSG_SEQ: 1 ACK_REQ: 0 VALID_ACK: 1MSID_TYPE: 2 IMSI: (Class: 0, Class_0_type: 0)[0x 01 f8 39 6a 15] 615-330-0644ASSIGN_MODE: Traffic Channel AssignmentADD_RECORD_LEN: 5 FREQ_INCL: 1 GRANTED_MODE: 2

CODE_CHAN: 43 FRAME_OFFSET: 2ENCRYPT_MODE: Encryption disabledBAND_CLASS: 800 MHz cellular bandCDMA_FREQ: 283

CHANNEL ASSIGNMENT MESSAGE

18:14:47.581 Forward Traffic Channel: OrderACK_SEQ: 7 MSG_SEQ: 0 ACK_REQ: 1ENCRYPTION: 0 USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order


Only about 400 ms. after the base stationacknowledgment order, the mobile receives

the channel assignment message.

The base station is alreadysending blank frames onthe forward channel,usingthe assigned Walsh code.

The mobile sees at least twogood blank frames in a row on

the forward channel, and

concludes this is the right trafficchannel. It sends a preambleof two blank frames of its ownon the reverse traffic channel.

The base station acknowledges

receiving the mobiles preamble.

The mobile station acknowledges the

base stations acknowledgment.Everybody is ready!

Service Negotiation and Mobile Alert


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18:14:47.835 Reverse Traffic Channel:Service Connect CompletionACK_SEQ: 1 MSG_SEQ: 3 ACK_REQ: 1ENCRYPTION: 0 SERV_CON_SEQ: 0

SERVICE CONNECT COMPLETE MSG.

18:14:47.760 Forward Traffic Channel: Service ConnectACK_SEQ: 0 MSG_SEQ: 1 ACK_REQ: 0 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0 SERV_CON_SEQ: 0Service Configuration: supported Transmission:Forward Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800 bpsReverse Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800 bpsService option: (6) Voice (13k) (0x8000)Forward Traffic Channel: Primary Traffic

Reverse Traffic Channel: Primary Traffic

SERVICE CONNECT MESSAGE

Now that both sides have arrived on thetraffic channel, the base stationproposes that the requested call

actually begin.

The mobile agrees andsays its ready to play.18:14:47.961 Forward Traffic Channel:Alert With Information

ACK_SEQ: 3 MSG_SEQ: 1 ACK_REQ: 1 ENCRYPTION: 0SIGNAL_TYPE = IS-54B AlertingALERT_PITCH = Medium Pitch (Standard Alert)SIGNAL = Long RESERVED = 0RECORD_TYPE = Calling Party NumberRECORD_LEN = 96 bits

NUMBER_TYPE = National NumberNUMBER_PLAN = ISDN/Telephony Numbering PlanPI = Presentation Allowed SI = Network ProvidedCHARi = 6153000124 RESERVED = 0 RESERVED = 0

ALERT WITH INFORMATION MESSAGE

The base station orders the mobile to ring, and

gives it the calling partys number to display.


The mobile says its ringing.

SERVICE CONNECT COMPLETE is a

major milestone in call processing. Up

until now, this was an access attempt.

Now it is officially a call.

The Human Answers! Connect Order


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The mobile has been ringing for severalseconds. The human user finallycomes over and presses the send

button to answer the call.

Now the switch completes the audio circuit andthe two callers can talk!

18:14:54.920 Forward Traffic Channel: OrderACK_SEQ: 0 MSG_SEQ: 1 ACK_REQ: 0ENCRYPTION: 0 USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order


18:14:54.758 Reverse Traffic Channel: OrderACK_SEQ: 6 MSG_SEQ: 0 ACK_REQ: 1ENCRYPTION: 0Connect Order

CONNECT ORDER


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Lets make an Outgoing Call!Lets make an Outgoing Call!


Placing an Outgoing Call


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The mobile user dials the desired digits, and presses SEND. Mobile transmits an Origination Message on the access channel.

The system acknowledges receiving the origination by sending abase station acknowledgement on the paging channel.

The system arranges the resources for the call and startstransmitting on the traffic channel.

The system notifies the mobile in a Channel Assignment Message

on the paging channel. The mobile arrives on the traffic channel.

The mobile and the base station notice each others traffic channelsignals and confirm their presence by exchanging

acknowledgment messages. The base station and the mobile negotiate what type of call this will

be -- I.e., 13k voice, etc.

The audio circuit is completed and the mobile caller hears ringing.

OriginationORIGINATION MESSAGE


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17:48:53.144 Access Channel: Origination

ACK_SEQ: 7 MSG_SEQ: 6 ACK_REQ: 1VALID_ACK: 0 ACK_TYPE: 0 MSID_TYPE: 3ESN: [0x 00 06 98 24] MFR 0 Reserved 1Serial Number 170020IMSI: (Class: 0, Class_0_type: 0)[0x 03 5d b8 97 c2] 972-849-5073AUTH_MODE: 0 MOB_TERM: 1SLOT_CYCLE_INDEX: 2 MOB_P_REV: 1 EXT_SCM: 1

DualMode: 0 SLOTTED_MODE: 1 PowerClass: 0REQUEST_MODE: CDMA only SPECIAL_SERVICE: 1Service option: (6) Voice (13k) (0x8000) PM: 0DIGIT_MODE: 0 MORE_FIELDS: 0 NUM_FIELDS: 11Chari: 18008900829NAR_AN_CAP: 0

ORIGINATION MESSAGE

17:48:53.487 Paging Channel: OrderACK_SEQ: 6 MSG_SEQ: 0 ACK_REQ: 0 VALID_ACK: 1MSID_TYPE: 2IMSI: (Class: 0, Class_0_type: 0)[0x 03 5d b8 97 c2] 972-849-5073

Base Station Acknowledgement Order


The mobile sends an

origination messageon the access

channel.

The base station confirmsthat the origination message

was received.17:48:54.367 Paging Channel: Channel AssignmentACK_SEQ: 6 MSG_SEQ: 1 ACK_REQ: 0 VALID_ACK: 1

MSID_TYPE: 2IMSI: (Class: 0, Class_0_type: 0)[0x 03 5d b8 97 c2] 972-849-5073ASSIGN_MODE: Traffic Channel Assignment,ADD_RECORD_LEN: 5 FREQ_INCL: 1 GRANTED_MODE: 2CODE_CHAN: 12 FRAME_OFFSET: 0ENCRYPT_MODE: Encryption disabledBAND_CLASS: 1.8 to 2.0 GHz PCS band

CDMA_FREQ: 425

CHANNEL ASSIGNMENT MESSAGE

The base station sends aChannel Assignment

Message and the mobile

goes to the traffic channel.

Traffic Channel Confirmation


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MOBILE STATION ACKNOWLEDGMENT17:48:54.757 Forward Traffic Channel: Order

ACK_SEQ: 7 MSG_SEQ: 0 ACK_REQ: 1 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order


The base station is alreadysending blank frames on

the forward channel,usingthe assigned Walsh code.

The mobile sees at least twogood blank frames in a row on

the forward channel, andconcludes this is the right traffic

channel. It sends a preambleof two blank frames of its ownon the reverse traffic channel.

The base station acknowledgesreceiving the mobiles preamble.

The mobile station acknowledges thebase stations acknowledgment.

Everybody is ready!

Service Negotiation and Connect Complete


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17:48:55.137 Reverse Traffic Channel: Service ConnectCompletion ACK_SEQ: 1, MSG_SEQ: 0, ACK_REQ: 1,ENCRYPTION: 0, SERV_CON_SEQ: 0

SERVICE CONNECT COMPLETE MSG.

17:48:55.098 Forward Traffic Channel: Service ConnectACK_SEQ: 7 MSG_SEQ: 1 ACK_REQ: 1 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0 SERV_CON_SEQ: 0Service Configuration Supported Transmission:Forward Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800 bpsReverse Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800 bps

Service option: (6) Voice (13k) (0x8000)Forward Traffic Channel: Primary TrafficReverse Traffic Channel: Primary Traffic

SERVICE CONNECT MESSAGENow that the traffic channel is working

in both directions, the base stationproposes that the requested call

actually begin.

The mobile agrees andsays its ready to play.

17:48:55.779 Forward Traffic Channel: OrderACK_SEQ: 0 MSG_SEQ: 0 ACK_REQ: 0 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order


The base station agrees. SERVICE CONNECT COMPLETE is amajor milestone in call processing. Up

until now, this was an access attempt.

Now it is officially a call.

Now the switch completes the audio circuit and

the two callers can talk!


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Lets End a Call!Lets End a Call!


Ending A Call


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A normal call continues until one of the parties hangs up. Thataction sends a Release Order, normal release.

The other side of the call sends a Release Order, no reason given.

If a normal release is seen, the call ended normally.

At the conclusion of the call, the mobile reacquires the system.

Searches for the best pilot on the present CDMA frequency

Reads the Sync Channel Message

Monitors the Paging Channel steadily Several different conditions can cause a call to end abnormally:

the forward link is lost at the mobile, and a fade timer acts

the reverse link is lost at the base station, and a fade timer acts

a number of forward link messages arent acknowledged, and thebase station acts to tear down the link

a number of reverse link messages arent acknowledged, and themobile station acts to tear down the link

A Beautiful End to a Normal Call


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17:49:21.715 Reverse Traffic Channel: OrderACK_SEQ: 1 MSG_SEQ: 1 ACK_REQ: 1ENCRYPTION: 0Release Order (normal release)

MOBILE RELEASE ORDER


17:49:21.936 Forward Traffic Channel: OrderACK_SEQ: 1 MSG_SEQ: 2 ACK_REQ: 0 ENCRYPTION: 0,USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order

At the end of a normal call, this

mobile user pressed end.

The mobile left the traffic channel,

scanned to find the best pilot, and readthe Sync Channel Message.

BASE STATION RELEASE ORDER

17:49:21.997 Forward Traffic Channel: OrderACK_SEQ: 1 MSG_SEQ: 3 ACK_REQ: 0 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0Release Order (no reason given)

17:49:22.517 Sync ChannelMSG_TYPE: 1 Sync Channel MessageP_REV: 1 MIN_P_REV: 1SID: 4112 NID: 2 Pilot_PN: 183LC_STATE: 0x318fe5d84a5SYS_TIME: 0x1ae9683dcLP_SEC: 9 LTM_OFF: -10 DAYLT: 1Paging Channel Data Rate: 9600

CDMA_FREQ: 425

SYNC CHANNEL MESSAGE

The base station acknowledgedreceiving the message, then sent

a release message of its own.


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Lets receive Notification

of a Voice Message!

Lets receive Notification

of a Voice Message!


Feature Notification

FEATURE NOTIFICATION MESSAGE


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98/06/30 21:16:44.368 [PCH] Feature Notification MessageMSG_LENGTH = 144 bitsMSG_TYPE = Feature Notification MessageACK_SEQ = 0MSG_SEQ = 0ACK_REQ = 1VALID_ACK = 0ADDR_TYPE = IMSI

ADDR_LEN = 56 bitsIMSI_CLASS = 0IMSI_CLASS_0_TYPE = 3RESERVED = 0MCC = 302IMSI_11_12 = 00IMSI_S = 9055170325RELEASE = 0

RECORD_TYPE = Message WaitingRECORD_LEN = 8 bitsMSG_COUNT = 1RESERVED = 0

FEATURE NOTIFICATION MESSAGE

The Feature Notification Message onthe Paging Channel tells a specificmobile it has voice messages waiting.

There are other record types to notifythe mobile of other features.

The mobile confirms it has received thenotification by sending a Mobile StationAcknowledgment Order on the access

channel.



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Lets do a Handoff!Lets do a Handoff!


The Detailed Rules of Soft Handoff


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Handset views pilots in sets Active: pilots of sectors actually in use

Candidates: pilots mobile requested, butnot yet set up & transmitting by system

Neighbors: pilots told to mobile by system,as nearby sectors to check

Remaining: any pilots used by system butnot already in the other sets (div. by PILOT_INC)

Handset sends Pilot Strength Measurement

Message to the system whenever triggered by: It notices a pilot in neighbor or remaining set

exceeds T_ADD

An active set pilot drops below T_DROP forT_TDROP time

A candidate pilot exceeds an active byT_COMP

The System may set up all requested handoffs,or it may apply special manufacturer-specificscreening criteria and authorize only some

6

5

Remaining

Active

Candidate

Neighbor 20

PILOT SETSMax.Members

Reqd.

ByStd.

T_COMP

T_ADD T_DROP

T_TDROP

HANDOFFPARAMETERS

Exercise: How does a pilotin one set migrate intoanother set, for all cases?Identify the trigger, and themessages involved.

The Call is Already Established. What Next?

All PN Offsets0


73/146


Ec/Io

0

0

32K

512

Chips

PN

0

-20

Neighbor Set

The call is already in progress.

PN 168 is the only active signal,

and also is our timing reference.

Continue checking the neighbors.

If we ever notice a neighbor with Ec/Io above T_ADD,

ask to use it! Send a Pilot Strength Measurement Message!

T_ADD

Rake Fingers

Reference PN

Active Pilot

10752

168

32000

500

14080

220

! !

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61

F2 PN168 W61

F3 PN168 W61

Mobile Requests the Handoff!


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98/05/24 23:14:02.205 [RTC]Pilot Strength Measurement MessageMSG_LENGTH = 128 bitsMSG_TYPE = Pilot Strength Measurement MessageACK_SEQ = 5 MSG_SEQ = 0 ACK_REQ = 1ENCRYPTION = Encryption Mode Disabled

REF_PN = 168 Offset Index (the Reference PN)PILOT_STRENGTH = -6.0 dBKEEP = 1PILOT_PN_PHASE = 14080 chips (PN220+0chips)PILOT_STRENGTH = -12.5 dBKEEP = 1PILOT_PN_PHASE = 32002 chips (PN500 + 2 chips)PILOT_STRENGTH = -11.0 dB

KEEP = 1RESERVED = 0

PILOT STRENGTH MEASUREMENT MESSAGE

98/05/24 23:14:02.386 [FTC] Order MessageMSG_LENGTH = 64 bitsMSG_TYPE = Order Message

ACK_SEQ = 0 MSG_SEQ = 0 ACK_REQ = 0ENCRYPTION = Encryption Mode DisabledUSE_TIME = 0 ACTION_TIME = 0ORDER = Base Station Acknowledgement OrderADD_RECORD_LEN = 0 bitsOrder-Specific Fields = Field OmittedRESERVED = 0


Just prior to this message, this particularmobile already was in handoff with PN 168

and 220.This pilot strength measurement messagereports PN 500 has increased aboveT_Add, and the mobile wants to use it too.

The base station acknowledges receiving

the Pilot Strength Measurement Message.

System Authorizes the Handoff!

HANDOFF DIRECTION MESSAGE


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98/05/24 23:14:02.926 [FTC] Extended Handoff Direction MessageMSG_LENGTH = 136 bitsMSG_TYPE = Extended Handoff Direction MessageACK_SEQ = 0 MSG_SEQ = 6 ACK_REQ = 1ENCRYPTION = Encryption Mode DisabledUSE_TIME = 0 ACTION_TIME = 0 HDM_SEQ = 0SEARCH_INCLUDED = 1SRCH_WIN_A = 40 PN chips

T_ADD = -13.0 dB T_DROP = -15.0 dB T_COMP = 2.5 dBT_TDROP = 4 secHARD_INCLUDED = 0FRAME_OFFSET = Field OmittedPRIVATE_LCM = Field Omitted RESET_L2 = Field OmittedRESET_FPC = Field Omitted RESERVED = Field OmittedENCRYPT_MODE = Field Omitted RESERVED = Field OmittedNOM_PWR = Field Omitted NUM_PREAMBLE = Field OmittedBAND_CLASS = Field Omitted CDMA_FREQ = Field Omitted

ADD_LENGTH = 0PILOT_PN = 168 PWR_COMB_IND = 0 CODE_CHAN = 61PILOT_PN = 220 PWR_COMB_IND = 1 CODE_CHAN = 20PILOT_PN = 500 PWR_COMB_IND = 0 CODE_CHAN = 50RESERVED = 0

The base station sends a HandofDirection Message authorizing themobile to begin soft handoff with allthree requested PNs. The pre-existinglink on PN 168 will continue to use

Walsh code 61, the new link on PN220will use Walsh Code 20, and the newlink on PN500 will use Walsh code 50.

The mobile acknowledges it has receivedthe Handoff Direction Message.

98/05/24 23:14:02.945 [RTC] Order Message

MSG_LENGTH = 56 bits MSG_TYPE = Order MessageACK_SEQ = 6 MSG_SEQ = 6 ACK_REQ = 0ENCRYPTION = Encryption Mode DisabledORDER = Mobile Station Acknowledgement OrderADD_RECORD_LEN = 0 bitsOrder-Specific Fields = Field Omitted RESERVED = 0


Mobile Implements the Handoff!


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The mobile searcher quickly re-checksall three PNs. It still hears their pilots!

The mobile sends a Handoff CompletionMessage, confirming it still wants to go

ahead with the handoff.

98/05/24 23:14:03.085 [FTC] Forward Traffic Channel: OrderACK_SEQ: 0 MSG_SEQ: 1 ACK_REQ: 0 ENCRYPTION: 0USE_TIME: 0 ACTION_TIME: 0Base Station Acknowledgement Order


98/05/24 23:14:02.985 [RTC] Handoff Completion MessageMSG_LENGTH = 72 bitsMSG_TYPE = Handoff Completion MessageACK_SEQ = 6 MSG_SEQ = 1 ACK_REQ = 1ENCRYPTION = Encryption Mode DisabledLAST_HDM_SEQ = 0PILOT_PN = 168 Offset Index

PILOT_PN = 220 Offset IndexPILOT_PN = 500 Offset IndexRESERVED = 0

HANDOFF COMPLETION MESSAGE

The base station confirms it hasreceived the mobiles HandoffCompletion message, and willcontinue with all of the linksactive.

Neighbor List Updated, Handoff is Complete!

NEIGHBOR LIST UPDATE MESSAGE


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98/05/24 23:14:03.245 [RTC] Order MessageMSG_LENGTH = 56 bits MSG_TYPE = Order MessageACK_SEQ = 7 MSG_SEQ = 7 ACK_REQ = 0ENCRYPTION = Encryption Mode DisabledORDER = Mobile Station Acknowledgement OrderADD_RECORD_LEN = 0 bitsOrder-Specific Fields = Field OmittedRESERVED = 0


98/05/24 23:14:03.166 [FTC] Neighbor List Update MessageMSG_LENGTH = 192 bitsMSG_TYPE = Neighbor List Update MessageACK_SEQ = 1 MSG_SEQ = 7 ACK_REQ = 1ENCRYPTION = Encryption Mode DisabledPILOT_INC = 4 Offset IndexNGHBR_PN = 164 Offset IndexNGHBR_PN = 68 Offset Index

NGHBR_PN = 52 Offset IndexNGHBR_PN = 176 Offset IndexNGHBR_PN = 304 Offset IndexNGHBR_PN = 136 Offset IndexNGHBR_PN = 112 Offset IndexNGHBR_PN = 372 Offset IndexNGHBR_PN = 36 Offset IndexNGHBR_PN = 8 Offset Index

NGHBR_PN = 384 Offset IndexNGHBR_PN = 216 Offset IndexNGHBR_PN = 328 Offset IndexNGHBR_PN = 332 Offset IndexNGHBR_PN = 400 Offset IndexNGHBR_PN = 96 Offset IndexRESERVED = 0

In response to the mobiles HandoffCompletion Message, the base stationassembles a new composite neighbor

list including all the neighbors of each ofthe three active pilots.This is necessary since the mobilecould be traveling toward any one ofthese pilots and may need to request

soft handoff with any of them soon.

The mobile confirms receiving theNeighbor List Update Message. It is

already checking the neighbor list andwill do so continuously from now on.

The handoff is fully established.

Handoff Now In Effect, keep checking Pilots!

All PN Offsets0


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Ec/Io

0

0

32K

512

Chips

PN

-20

Neighbor Set

Continue checking each ACTIVE pilot. If any are less than T_DROP and remain

so for T_TDROP time, send Pilot Strength Measurement Message, DROP IT!!

Continue checking each NEIGHBOR pilot. If any ever rises above T_ADD, send

PSMM, ADD IT! Keep watching CANDIDATES vs ACTIVES using T_COMP, too.

T_ADD

Rake Fingers

Reference PN

Active Set

10752

168

32000

500

14080

220

T_DROP

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61

F2 PN500 W50

F3 PN220 W20

The Complete Picture of Handoff & Pilot Sets

o

All PN Offsets0


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T_ADD

Ec/Io

0

0

32K

512

Chips

PN

-20

Neighbor Set

SRCH_WIN_N

Active Set

Candidate SetT_DROP

SRCH_WIN_A

Remaining Set

T_ADDSRCH_WIN_R

SRCH_WIN_A

T_DROP

Rake Fingers

Reference PN

Pilots of sectorsnow used forcommunication

Pilots requestedby mobile but notset up by system

Pilots suggestedby system for

more checking

All other pilots divisible by PILOT_INC but notpresently in Active, Candidate, or Neighbor sets

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61

F2 PN500 W50

F3 PN220 W20

Timing of Pilot Searchers Measurement Process

CURRENT PILOT SET CONTENTS

R


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The searcher checks pilots in nestedloops, much like meshed gears.Actives and candidates

occupy the fastest-spinning wheel.

Neighbors arenext, advancingone pilot for eachAct+Cand. revolution.Remaining is slowest,

advancing one pilot eachtime the Neighbors revolve.

A A A

C

N N N N N N N N N N N N

R R R R R R R R R R R R


R R R R R R R R R R R RR R R R R R R R R R R R






R R R R

31

12112

PILOT SEARCHER VIEWED IN SEQUENCE: Typical Elapsed Time = 4 seconds

A A A C N

R

A A A C A A A C A A A C A A A C A A A C A A A CN N N N N N

A A A C N A A A C A A A C A A A C A A A C A A A C A A A CN N N N N

A A A CN A A A C A A A C A A A C A A A C A A A C A A A CN N N N N N

N A A A C A A A C A A A CN N N R A A A C N A A A C A A A C A A AN N

C A A A C A A A CN N N

R

A A A C N A A A C A A A C A A AN N C A A AN

C A A A CN N Only 3 of 112 remaining set pilots have been checked thus far!

A

N

R

R

R

R

R

R

NN

N

N

N

N

NN

AA

Overall Handoff Perspective


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Soft & Softer Handoffs are preferred, but not always possible

a handset can receive BTS/sectors simultaneously only on onefrequency

all involved BTS/sectors must connect to a networked BSCs.Some manufacturers do not presently support this, and so areunable to do soft-handoff at boundaries between BSCs.

frame timingmust be same on all BTS/sectors

If any of the above are not possible, handoff still can occur but canonly be hard break-make protocol like AMPS/TDMA/GSM

intersystem handoff: hard

change-of-frequency handoff: hard CDMA-to-AMPS handoff: hard, no handback

auxiliary trigger mechanisms available (RTD), Ec/Io

Global Service Redirection Messages on outlooking sectors.

Troubleshooting Call Events:Watch Messaging, Mobile State


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Your current capabilities Earlier in this course we reviewed handset call processing

states

You have just seen the entire vocabulary of messages

ordinarily used in call processing Now youre equipped to do serious troubleshooting of CDMA

calls!

Auditing Call Processing Problems using messages

Watch the messages from birth (origination) to death (release)

is the order proper? are there inappropriate responses?

are any messages repeated? why? which link is bad?

are any messages missed or not acknowledged?

are contents and included parameter values reasonable?

is the timing appropriate -- delays not too long?

track the state in which the mobile and system should be


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Course 302

CDMA Performance Indicators

and Problem Signatures

CDMA Performance Indicators

and Problem Signatures

Introducing CDMA RF Performance Indicators

Earlier we compared a Cockpit Voice Recorder in aviation to the message


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files captured by CDMA drive-test equipment. Continuing this analogy, a Flight Data Recorder logs aircraft operational

settings. Its CDMA equivalent is a file of RF performance indicatorscaptured by drive-test equipment.

Key CDMA parameters and measurements show the condition of the RFenvironment. They are the primary gauges used to guide CDMAoptimization and troubleshooting

some indicate uplink conditions, some downlink, and some, both.

these parameters are collected primarily at the subscriber end of the

link, and thus are easy to capture using readily available commercialequipment without requiring assistance at the BSC

Understanding these parameters and their important implications requiresbasic knowledge in several subject areas:

General: RF units, transmitter and receiver basics

CDMA and spread-spectrum signal characteristics channel definitions

power control systems

basic CDMA call processing flow

signal behavior characteristics in noise and interference

Key CDMA RF Performance Indicators


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FER Frame Erasure Rate on forward channel

(realized at Handset)

on reverse channel

(realized at base station) FER is an excellent call

quality summary statistic

Mobile Receive Power

usually expressed in dBm

measured derived fromhandset IF AGC

broadband, unintelligentmeasurement: includes allRF in the carrier bandwidthregardless of source, not

just RF from serving BTS

-40

-90

-105

>RX Level

FER

%

0 2 5 100

Forward

Reverse

x

LO

RX Level(from AGC)

IFLNA

BW~30

MHz.

BW1.25MHz.

Handset Receiver

R

R

R

S

Rake

More Key CDMA RF Performance Indicators


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Ec/Io cleanness of the pilot

foretells the readability ofthe associated traffic

channels guides soft handoff decisions digitally derived: ratio of good

to bad energy seen by the

search correlator at thedesired PN offset Never appears higher than

Pilots percentage of servingcells transmitted energy

Can be degraded by strongRF from other cells, sectors

Imperfect orthogonality,other PNs are ~-20 dB.

Can be degraded by noise

Ec/Io dB

-25 -15 -10 0

Ec

Io

Energy of

desired pilot alone

Total energy received

Li ht T ffi L di

How Ec/Io Varies with Traffic Loading


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Light Traffic Loading

Heavily Loaded

Each sector transmits a certainamount of power, the sum of:

pilot, sync, and paging

any traffic channels in useat that moment

Ec/Io is the ratio of pilot powerto total power

On a sector with nobodytalking, Ec/Io is typicallyabout 50%, which is -3 db

On a sector with maximum

traffic, Ec/Io is typicallyabout 20%, which is -7 db.

Ec/Io = (2/4)= 50%

= -3 db.

Ec/Io = (2/10)

= 20%= -7 db.

2w

1.5w

Pilot

Paging

Sync

I0

EC

TrafficChannels

6w

0.5w

2w

1.5w

Pilot

Paging

Sync I0EC

0.5w

O S t D i t

How Ec/Io varies with RF Environment

I l it ti


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Many Sectors, Nobody Dominant

One Sector Dominant In a clean situation, onesector is dominant and themobile enjoys an Ec/Io justas good as it was when

transmitted In pilot pollution, too many

sectors overlap and themobile hears a soup madeup of all their signals

Io is the power sum of allthe signals reaching themobile

Ec is the energy of a

single sectors pilot The large Io overrides the

weak Ec; Ec/Io is low!

Io = -90 dbmEc = -96 dbmEc/Io = -6 db

Io = 10 signalseach -90 dbm

= -80 dbmEc of any onesector = -96

Ec/Io = -16 db

2w

1.5w

Pilot

Paging

Sync

I0

EC

Traffic

Channels

4w

0.5w

BTS1

I0

EC

BTS2

BTS3

BTS4

BTS5

BTS6

BTS7

BTS8

BTS9

BTS10

PilotSync & Paging

Traffic

PilotSync & Paging

Traffic

PilotSync & Paging

Traffic

Pil

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302 - CDMA Performance Optimization Using Grayson’s Surveyor

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