CDMA Networks Intro

7/30/2019 CDMA Networks Intro

1/137

Page 1Course 134v1.7 (c) 2011 AA

Current CDMA NetworksArchitectures, Algorithms, & Performance


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Section A

CDMA Principles Review


3/137


CDMA: Using A New Dimension

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

CDMA operates by using CODING todiscriminate between users

CDMA interference comes mainly fromnearby users

Each user is a small voice in a roaringcrowd -- but with a uniquely recoverablecode

CDMA

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

AMPS: +17 dB

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

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


4/137


DSSS Spreading: Time-Domain View

At Originating Site: Input A: Users Data @

19,200 bits/second

Input B: Walsh Code #23@ 1.2288 Mcps

Output: Spread

spectrum signal

At Destination Site: Input A: Received

spread 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


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Spreading from a Frequency-Domain View

Traditional technologies tryto squeeze signal intominimum requiredbandwidth

CDMA uses largerbandwidth but usesresulting processing gain toincrease capacity

Spread Spectrum Payoff:Processing Gain

Spread Spectrum

TRADITIONAL COMMUNICATIONS SYSTEM

SlowInformation

Sent

TX

SlowInformationRecovered

RX

NarrowbandSignal

SPREAD-SPECTRUM SYSTEM

Fast

SpreadingSequence

SlowInformation

Sent

TX

SlowInformationRecovered

RX

Fast

SpreadingSequence

WidebandSignal


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CDMA Uses Code Channels

The purpose of a CDMA system is to transmit bitsfrom one user to another

Vocoder bits are the payload in voice calls

Fax or Web TCP/IP data bits are also possible

A CDMA signal uses many chips to convey just

one bit of information

Each user has a unique chip pattern, in effect achannel made from codes

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

Other users code patterns appear random andadd up in a random self-canceling fashion; theydont disturb the bit decoding decision beingmade regarding information transmitted on theproper code pattern

Building aCDMA Signal

Bitsfrom Users Vocoder

Symbols

Chips

Forward ErrorCorrection

Coding and

Spreading


7/137Page 7Course 134v1.7 (c) 2011 AA

Sneak Preview: How One Traffic ChannelIs Transmitted by One Sector to a Mobile

S

if 1 =if 0 =

1

AnalogSummingUsers

QPSK RF

S

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 ofCDMA signalgeneration at the sector and recovery at the mobile.The complete coding process uses two additional codes,

as described in following slides.


8/137Page 8Course 134v1.7 (c) 2011 AA

Spreading: What we do, we can undo

Sender combines data with a fast spreading sequence, transmits

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

to extract original data

ORIGINATING SITE DESTINATION

SpreadingSequence

SpreadingSequence

InputData

RecoveredData

Spread Data Stream


9/137Page 9Course 134v1.7 (c) 2011 AA

Shipping and Receiving via CDMA

Whether in shipping and receiving, or in CDMA, packaging isextremely important!

Cargo is placed inside nested containers for protection and toallow addressing

The shipper packs in a certain order, and the receiver unpacks in

the reverse order CDMA containers are spreading codes

FedEx

Data Mailer

FedEx

DataMailer

Shipping Receiving


10/137Page 10Course 134v1.7 (c) 2011 AA

CDMAs Nested Spreading Sequences

CDMA combines three different spreading sequences to create unique,

robust channels The sequences are easy to generate on both sending and receiving ends of

each link

What we do, we can undo

SpreadingSequence

A

SpreadingSequence

B

SpreadingSequence

C

SpreadingSequence

C

SpreadingSequence

B

SpreadingSequence

A

InputData

X

RecoveredData

X

X+A X+A+B X+A+B+C X+A+B X+ASpread-Spectrum Chip Streams

ORIGINATING SITE DESTINATION


11/137Page 11Course 134v1.7 (c) 2011 AA

One of the CDMA Spreading Sequences:Walsh Codes

64 Magic Sequences, each 64 chips long Each Walsh Code is precisely Orthogonal with

respect to all other Walsh Codes

its simple to generate the codes, or

theyre small enough to use from ROM

WALSH CODES# ------------------- --------------- 64-Chip Sequence ----------------------------------------- -0 00000000000000000000000000000000000000000000000000000000000000001 01010101010101010101010101010101010101010101010101010101010101012 0011001100110011001100110011001100110011001100110011001100110011

3 01100110011001100110011001100110011001100110011001100110011001104 00001111000011110000111100001111000011110000111100001111000011115 01011010010110100101101001011010010110100101101001011010010110106 00111100001111000011110000111100001111000011110000111100001111007 01101001011010010110100101101001011010010110100101101001011010018 00000000111111110000000011111111000000001111111100000000111111119 0101010110101010010101011010101001010101101010100101010110101010

10 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 0110100101101001100101101001011001101001011010011001011010010110

24 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

EXAMPLE:

Correlation of Walsh Code #23 with Walsh Code #59

#23 0110100101101001100101101001011001101001011010011001011010010110

#59 0110011010011001100110010110011010011001011001100110011010011001

Sum 0000111111110000000011111111000011110000000011111111000000001111

Correlation Results: 32 1s, 32 0s: Orthogonal!!

Unique Propert ies:

Mutual Orthogonality


12/137Page 12Course 134v1.7 (c) 2011 AA

Other Sequences: Generation & Properties

Other CDMA sequences aregenerated in shift registers

Plain shift register: no fun,sequence = length of register

Tapped shift register generates a

wild, self-mutating sequence 2N

-1chips 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


13/137Page 13Course 134v1.7 (c) 2011 AA

Another CDMA Spreading Sequence:The Short PN Code

The short PN code consists of twoPN Sequences, I and Q, each32,768 chips long

Generated in similar butdifferently-tapped 15-bit shift

registers Theyre always used together,

modulating the two phase axesof a QPSK modulator

IQ

32,768 chips long26-2/3 ms.

(75 repetitions in 2 sec.)CDMA QPSK Phase ModulatorUsing I and Q PN Sequences

I-sequence

Q-sequence

S

cos wt

sin wt

chip

input

QPSK-modulated

RFOutput

*

* In BTS, I and Q are used in-phase.In handset, Q is delayed 1/2 chip toavoid zero-amplitude crossings whichwould require a linear power amplifier


14/137Page 14Course 134v1.7 (c) 2011 AA

Third CDMA Spreading Sequence: Long CodeGeneration & Masking to establish Offset

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

Each handset codes its signal with the PN Long Code, but at a unique offset

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 different PNlong code offsets will appear practically orthogonal

Long Code Register(@ 1.2288 MCPS)

Public Long Code Mask(STATIC)

User Long CodeSequence(@1.2288 MCPS)

1 1 0 0 0 1 1 0 0 0 P E RMU T E D E S NAND

=S UM

Modulo-2 Addition


15/137Page 15Course 134v1.7 (c) 2011 AA

Putting it All Together: CDMA Channels

The three spreading codes are used in different ways to create theforward and reverse links

A forward channel exists by having a specific Walsh Code assigned to theuser, and a specific PN offset for the sector

A reverse channel exists because the mobile uses a specific offset of theLong PN sequence

BTS

WALSH CODE: Individual UserSHORT PN OFFSET: Sector

LONG CODE OFFSET:

individual handset

FORWARD CHANNELS

REVERSE CHANNELS

LONG CODE:DataScrambling

WALSH CODES:

used as symbolsfor robustness

SHORT PN:used at 0 offset

for tracking

OneSector


16/137Page 16Course 134v1.7 (c) 2011 AA

Section B

IS-95 CDMA Forward andReverse Channels


17/137Page 17Course 134v1.7 (c) 2011 AA

How a BTS Builds the Forward Code Channels

BSCor

AccessManager

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 Code

PN Offset 246

Trans-mitter,

Sector X

Switch

more

a Channel Element

A Forward Channelis identified by:

its CDMA RFcarrierFrequency

the unique Short

Code PN Offset ofthe sector

the unique WalshCode of the user

FECWalsh #23

SQ

SI

x

x

+

coswt

s inwt

I Q


18/137Page 18Course 134v1.7 (c) 2011 AA

Functions of the CDMA Forward Channels

PILOT: WALSH CODE 0

The Pilot is a structural beacon whichdoes not contain a character stream. It is atiming source used in system acquisitionand as a measurement device duringhandoffs

SYNC: WALSH CODE 32 This carries a data stream of system

identification 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 20Sync Walsh 32

Walsh 42

Walsh 37

Walsh 41

Walsh 56

Walsh 60

Walsh 55


19/137Page 19Course 134v1.7 (c) 2011 AA

Code Channels in the Reverse Direction

BSC,CBSC,

AccessManager

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 carrierFrequency

the unique Long Code PN Offsetof the individual handset

Channel Element

Channel Element

Channel Element

Long Code Gen

Long Code Gen

Long Code Gen

Long Code Gen

more

a Channel Element

Long

Codeoffset LongCodeoffset Long

Codeoffset

LongCodeoffset

Long

Codeoffset

LongCodeoffset

Channel Element

Long Code Gen


20/137Page 20Course 134v1.7 (c) 2011 AA

REG

1-800

242

4444

BTS

Although a sector can have up to seven paging channels, and each paging channelcan have up to 32 access channels, nearly all systems today use only one paging

channel per sector and only one access channel per paging channel.

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 really just 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 yetin a call to transmit registration requests, call setuprequests, page responses, order responses, andother signaling information

an access channel is really just a public longcode offset unique to the BTS sector

Access channels are paired to Paging Channels.Each paging channel can have up to 32 accesschannels.


21/137Page 21Course 134v1.7 (c) 2011 AA

Basic CDMA Network Architecture

Access Manageror (C)BSCSwitch BTS

Ch. Card ACC

Sa

Sb

Sc

TFU1

GPSRBSM

CDSU

CDSU

SBSVocodersSelectors

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS GPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2

DS0 in T1

PacketsChips

RFChannelElementVocoder


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Forward Traffic Channel:Generation Details from IS-95

Walsh

function

PowerControl

Bit

I PN

9600bps4800 bps

2400 bps

1200 bps

or

14400 bps7200 bps

3600 bps

1800 bps

(From Vocoder)

Convolutional

Encodingand

Repetition SymbolPuncturing

(13 kb only)

1.2288

McpsLong PN Code

Generation

19.2ksps

800Hz

R=1/2

QPN

Decimator DecimatorUserAddress

Mask

(ESN-based)

19.2ksps

1.2288

McpsScrambling

bi ts symbols ch ips

19.2ksps

28.8ksps

CHANNEL ELEMENT

M

U

X

Block

Interleaving


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Reverse Traffic Channel:Generation Details from IS-95

9600 bps4800 bps2400 bps1200 bps

or

14400 bps

7200 bps3600 bps1800 bps

28.8ksps

R = 1/3

1.2288McpsUser Address

Mask

LongPN Code

Generator

28.8ksps

Orthogonal

Modulation

Data BurstRandomizer

307.2kcps

1.2288Mcps

QPN(no offset)

IPN(no offset)

D

1/2 PNChipDelay

DirectSequenceSpreading

R = 1/2

Convolutional

Encoder &

Repetition

Block

Interleaver


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Section C

IS-95 Operational DetailsVocoding, Multiplexing, Power Control


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Variable Rate Vocoding & Multiplexing

Vocoders compress speech, reduce bitrate, greatly increasing capacity

CDMA uses a superior Variable RateVocoder

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

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

Each network manufacturer uses FER-based triggers and initial,minimum, and maximum traffic channel DGU values

ForwardRF

BSC BTS (1 sector)

Sync

Pilot

Paging

more

Short PN

Trans-mitter,

Sector XS I QUser 1User 2

User 3Vocoder/Selector

Help!


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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


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Details of Reverse Link Power Control

TXPO Handset Transmit Power

Actual RF power output of thehandset transmitter, includingcombined effects ofopen looppower control from receiverAGC andclosed loop powercontrol by BTS

cant exceed handsets maximum

(typ. +23 dBm)

TXGA Transmit Gain Adjust

Sum of all closed-loop power

control commands from the BTSsince the beginning of this call

TXPO

DUP x IFLNA

Subscriber Handset

R

R

R

S

Rake

S ViterbiDecoder

Vocoder

~

FECOrthMod

Long PN

x

x

x

IF Mod

I

Q

x ~LO

Open Loop

LO

Closed Loop Pwr Ctrl

IF

Receiver>>


29/137


Course 134

CDMA Air Interface Capacity


30/137


The Basic CDMA Capacity Equation

As this spreadsheet shows, actual traffic capacity is influencedstrongly by the degree of soft handoff actually in progress

Basic Capacity of a CDMA Cell

Case A Case B

Vocoder or Data Rate, kb/s 9.6 14.4 (9.6 for Rate Set 1, 14.4 for Rate Set 2)

Bandwidth, MHz. 1.25 1.25 (IS-95/J-Std 008 is 1.25 MHz.)

Eb/No in dB 7 7 5.01 Eb/No as ratio

Voice Duty fac tor 0.40 0.40 100% when talk ing, 12.5% when lis tening

Freq Reuse Efficiency 0.60 0.60 fraction of energy coming from within same cell

Sectorizat ion Gain 2.55 2.55 (2.55 observed for 3-sector cells in tests)

Gross Number of Users/Cell 99.4 66.2

Percentage of Users in Soft Handoff 50% 50%

Net Unique Users Per Cell 66.2 44.2


31/137


Capacity Issues with Current CDMA Networks

Today, CDMA networks for the most part are still single-carrier this severely limits the capacity of one BTS to approximately 20

erlangs

implementing additional carriers brings logistical problemsinvolving handoffs and system acquisition by mobiles

Multiple-carrier operation is essential to achieve reasonablecapacities

Within networks, there are strategies for squeezing the most out ofoverloaded single-carrier BTSs. Some of the main points are:

reduce Pilot, Sync, and Paging levels as low as possible,

thereby gaining precious additional energy for traffic channels reduce BTS traffic channel DGU settings as low as possible

without provoking forward link FER.


32/137


Wireless System Capacity Comparisons

Each wireless technology (AMPS,NAMPS, D-AMPS, GSM, CDMA)uses a specific modulation typewith its own unique signalcharacteristics

Signal Bandwidth determineshow many RF signals will fit inthe operators licensed spectrum

Robustness of RF signaldetermines tolerable level ofinterference and necessaryphysical separation of cochannelcells

Number of users per RF signaldirectly affects capacity

In the following page, we willdevelop the number of users andtraffic in erlangs per site for eachof the popular wirelesstechnologies

AMPS, D-AMPS, N-AMPS

CDMA

30 30 10 kHz Bandwidth

200 kHz

1250 kHz

1 3 1 Users

8 Users

22 Users1

1

11

1

11

11

1

1 1 1

1

12

34

4

32

56

17

Typical Frequency Reuse N=7



Vulnerability:

C/I @ 17 dB

Vulnerability:

C/I @ 6.5-9 dB

Vulnerability:EbNo@ 6 dB


33/137


Comparison of Wireless System Capacities

Fwd/Rev Spectrum kHz. 12,500 12,500 12,500 15,000 15,000 15,000 5,000 5,000 5,000

Technology AMPS TDMA CDMA TDMA GSM CDMA TDMA GSM CDMA

Req'd C/I or Eb/No, db 17 17 6 17 12 6 17 12 6

Freq Reuse Factor, N 7 7 1 7 4 1 7 4 1

RF Signal BW, kHz 30 30 1250 30 200 1250 30 200 1250

Total # RF Carriers 416 416 9 500 75 11 166 25 3

RF Sigs. per cell @N 59 59 9 71 18 11 23 6 3

# Sectors per cell 3 3 3 3 3 3 3 3 3#CCH per sector 1 1 0 1 0 0 1 0 0

RF Signals per sector 18 18 9 22 6 11 6 2 3

Voicepaths/RF signal 1 3 22 3 8 22 3 8 22

SH average links used 1.66 1.66 1.66

Unique Voicepaths/carrier 13.253 13.253 13.253

Voicepaths/Sector 18 54 198 66 48 242 18 16 66

Unique Voicepaths/Sector 18 54 119 66 48 145 18 16 39

P.02 Erlangs per sector 11.5 44 105.5 55.3 38.4 130.9 11.5 9.83 30.1

P.02 Erlangs per site 34.5 132 316.5 165.9 115.2 392.7 34.5 29.49 90.3

Capacity vs. AMPS800 1 3.8 9.2 4.8 3.3 11.4 1.0 0.9 2.6

800 Cellular (A,B) 1900 PCS (A, B, C) 1900 PCS (D, E, F)

824 835 845 870 880

8

9

4

869

849

846.5825

8

9

0

891.5

Paging, ESMR, etc.A B A B

A D B E F C unlic.dataunlic.voice A D B E F C

1850MHz.

1910MHz.

1990MHz.

1930MHz.

15 15 155 5 5 15 15 155 5 5


34/137


Multicarrier CDMA Capacity Implications

Fwd/Rev Spectrum kHz. 12,500 1,800 3,050 4,300 5,550 6,800 8,050 9,300 10,550 11,800 13,050 14,300

Technology AMPS CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA

Req'd C/I or Eb/No, db 17 6 6 6 6 6 6 6 6 6 6 6

Freq Reuse Factor, N 7 1 1 1 1 1 1 1 1 1 1 1

RF Signal BW, kHz 30 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250

Total # RF Carriers 416 1 2 3 4 5 6 7 8 9 10 11

RF Sigs. per cell @N 59 1 2 3 4 5 6 7 8 9 10 11

# Sectors per cell 3 3 3 3 3 3 3 3 3 3 3 3

#CCH per sector 1 0 0 0 0 0 0 0 0 0 0 0

RF Signals per sector 18 1 2 3 4 5 6 7 8 9 10 11

Voicepaths/RF signal 1 22 22 22 22 22 22 22 22 22 22 22

SH average links used 1 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66Unique Voicepaths/carrier 1 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3

Voicepaths/Sector 18 22 44 66 88 110 132 154 176 198 220 242

Unique Voicepaths/Sector 18 13 26 39 53 66 79 92 106 119 132 145

P.02 Erlangs per sector 11.5 7.4 18.4 30.1 43.1 55.3 67.7 80.2 93.8 105.5 119.1 130.9

P.02 Erlangs per site 34.5 22.2 55.2 90.3 129.3 165.9 203.1 240.6 281.4 316.5 357.3 392.7

Capacity vs. AMPS800 1 0.64 1.60 2.6 3.7 4.8 5.9 7.0 8.2 9.2 10.4 11.4

f

1 2 3 4 5 6 7 8 9 10 11

CDMA Carrier Frequencies


35/137


Course 134

Nortel CDMA NetworkArchitecture

www.nortel.com


36/137


BASE STATION

CONTROLLER

SUPPORT

FUNCTIONS

BASE STATIONS

Mobile TelephoneSwitching Office

PSTN

Local Carriers

Long Distance

CarriersATM Link

to other CDMA

Networks

(Future)

Structure of a Typical Wireless System

Voice Mail System SWITCH

HLR Home Location Register

(subscriber database)


37/137


Signal Flow: Two-Stage Metamorphosis

BSC-BSMMTX BTS

Ch. Card ACC

Sa

Sb

Sc

TFU1

GPSRBSM

CDSU

CDSU

SBS

VocodersSelectors

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS GPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2

DS0 in T1

PacketsChips

RFChannelElementVocoder


38/137


NORTEL CDMA System Architecture

BSC-BSMMTX BTS

CDSU DISCO

Ch. Card ACC

SaSbSc

TFU1

GPSRBSM

CDSU

CDSU

DISCO 1

DISCO 2

SBSVocoders

Selectors

CDSU

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

PSTN &Other MTXs

GPS GPS

IOC

Billing Current Product Capabilities:Each BSC can have up to 4 DISCO shelves

About 240 sites, roughly 6000 erlangs capacityEach MTX can have up to 2 BSCs


39/137


Switch: The Nortel MTX

Primary functions

Call Processing Mobility Management

HLR-VLR access

Intersystem call delivery (IS-41C)

Inter-MTX handover (IS-41C)

Billing Data Capture

Calling Features & Services

Collecting System OMs, Pegs

High reliability, redundancy

MTX

CMSLM

LPP ENET

DTCs

DMS-BUS

PSTN &Other MTXs

CDMABSCUnch. T1

IOC

CDMASBS

MAP,VDUs

Billing

LPP

CCS7

Ch.T1

ChT1


40/137


The Nortel BSC

Primary functions

vocoding

soft handoff management

FER-based power control

routing of all traffic and controlpackets

Scaleable architecture

expand SBS to keep pace withtraffic growth

expandable DISCO

BSC

TFU1

GPSRBSM

CDSU

CDSU

DISCO 1

DISCO 2

SBSVocoders

Selectors

CDSU

CDSU

CDSU

CDSU

CDSU

CDSU

GPS

MTX(voice

trunks)

MTXLPP

BTSs

T1 channelized (24 DS0)

T1 unchannelized

BCN link (HDLC)


41/137


The Nortel BTS

Base Transceiver Station

Primary function: Air link generate, radiate, receive CDMA RF

signal IS-95/J.Std. 8

high-efficiency T1 backhaul

test capabilities

Configurations

1, 2, or 3 sectors

800 MHz.: indoor

1900 MHz.: self-contained outdoor,

remotable RFFEs new indoor, 800 MHz. & 1900 MHz.

multi-carrier options

Metrocell

BTS

CDSU DISCO

Ch. Card ACC

SaSbSc

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS

BSC


42/137


The Nortel BSM

Base Station Manager

Primary functions: OA&M for CDMAcomponents

Configuration management

BSC, BTS configuration andparameters

Fault managementAlarm Reporting

Performance management

interface for CDMA statisticsand peg counts collection

Security management

Unix-based

BSC BTS

CDSU DISCO

Ch. Card ACC

SaSbSc

TFU1

GPSR

CDSU

CDSU

DISCO 1

DISCO 2

SBSVocoders

Selectors

CDSU

CDSU

CDSU

CDSU

CDSU

CDSU

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS GPS

BSM

X-Windows terminals

Ethernet LAN

BSM Workstation

GNP TELCO

WORKSERVER

SHELF---------

HIGHAVAILABILITY

NORTEL CDMABSM

BCN Links


43/137


Nortel Operational Capacity Considerations

BSC-BSMMTX BTS

Ch. Card ACC

Sa

Sb

Sc

TFU1

GPSRBSM

CDSU

CDSU

SBSVocoders

Selectors

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS

GPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2

Sufficient vocoders/selectorsrequired in BSC SBS, one persimultaneous call on the system.

8 Vocoders per SBS card, 12cards per shelf, 4 shelves per

SBS cabinet.

One T-1 can carry alltraffic originated by a

one-carrier BTS; specialconsideration required if

daisy-chaining

Forward RF Capacity:links use available

BTS TX power

Sufficient channelelements required fortraffic of all sectors:one CE per link; 20

CE per Channel Card

64 Walsh Codes/sector



DISCO has192 ports

max. Each

BTS uses 1,SBS shelf 1,LPP CIU 1,

Link 2, Ctrl. 2,BSM 4.

Typical CM processorcapacity considerations

PSTN trunk groups mustbe dimensioned to

support erlang load.

DTC & ENET:One port perVocoder plusone port per

outgoing trunk.

CDMA LPP:One pairCIUs andOne pairCAUs per

approx. 600erlangs

Reverse RF Capacity:links cause noise floorrise, use mobile power

1-2001 Current Product Capabilities:Each BSC can have up to 4 DISCO shelves

About 240 sites, roughly 6000 erlangs capacityEach MTX can have up to 2 BSCs


44/137


Course 134

CDMA Handset Architecture


45/137


Functional Anatomy of a CDMA Handset

Duplexer &Bandpass

Filters

IFBPF

MixerLNA

LocalOscillator

(Synthesized)

ViterbiDecoder

Vocoder

Search Correlator (Pilots)

PN Generator Walsh=0

IF

CPU &Control

Algorithms

VocoderConv. Encoder& Symbol Rep.

BlockInterleaver

OrthogonalModulator

Data BurstRandomizer

Direct Seq.Spreading

QuadratureSpreading

BasebandFiltering

IFModulator

PowerAmplifier

IF

Antenna

Receiver

Transmitter

bi ts

bi tsaudio

audio

symbolsch ips

Mixer

ch ips symbols symbols

RF IF

RF

RF

LO

LO

IF

Open Loop Pwr Control

messages

messagesLONG CODE Generator

IF

IF Transm it Gain Adjust : Closed Loop Pwr Control

Traffic Correlator

PN Generator Walsh Generator

Traffic Correlator


Traffic Correlator



46/137


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

RFPN WalshPN Walsh

PN Walsh

SearcherPN W=0

SVoice,Data,

Messages

Pilot Ec/Io

BTS

BTS


47/137


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

SearcherPN W=0

S Voice,Data,Messages

Pilot Ec/Io

BTS

BSCSwitch

BTS

Sel.


48/137


Adventures in Call Processing5 Minutes in the Life of a CDMA Handset


49/137


Our Call Processing Adventures

Layer-3 Messaging Review 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!


50/137


Layer-3 Messaging Review

CDMA Call Processing


51/137


How CDMA Messages are Sent

CDMA messages on both forwardand reverse traffic channels arenormally sent via dim-and-burst

Messages include many fields ofbinary data

The first byte of each messageidentifies message type: this allows

the recipient to parse the contents To ensure no messages are

missed, all CDMA messages bearserial numbers and importantmessages contain a bit requestingacknowledgment

Messages not promptlyacknowledged are retransmittedseveral times. If not acknowledged,the sender may release the call

Field data processing tools captureand display the messages for study

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

t

Message Vocabulary: Acquisition & Idle States


52/137


Message Vocabulary: Acquisition & Idle States

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 2011Msg

Service Redirection Msg

General Page Msg

Null Msg Data Burst Msg

Access Channel

Registration Msg

Order MsgMobile Station Acknowldgment

Long Code Transition RequestSSD UpDate 2011Confirmation

many others..

Origination Msg

Page Response Msg

Authentication ChallengeResponse Msg

Status Response Msg

TMSI AssignmentCompletion Message

Data Burst Msg

BTS

M V b l C ti St t


53/137


Message Vocabulary: Conversation State

Reverse Traffic Channel

Order Message

Mobile Sta. Acknowledgment

Long Code TransitionRequest

SSD UpDate 2011Confirmation

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 AcknowledgmentBase Station ChallengeConfirmation

Message Encryption Mode

AuthenticationChallenge Msg

Alert WithInformation Msg

Data Burst Msg

Analog HandoffDirection Msg

In-Traffic SystemParameters Msg

Neighbor ListUpDate 2011Msg

Send Burst DTMF Msg

Power ControlParameters Msg.

Retrieve Parameters Msg

Set Parameters Msg

SSD UpDate 2011Msg

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


54/137


Lets Acquire the System!


Fi d F ith CDMA RF Si l


55/137


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 5

etc.

Forward Link Frequencies(Base Station Transmit)

A D B E F C unlic.data unlic.voice A 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)

Fi d St t Pil t R d S Ch l


56/137


Find Strongest Pilot, Read Sync Channel

Rake FingersReference PN

Active Pilot

E

c/Io

00

32K512

ChipsPN

1. Pilot SearcherScans the Entire Range of PNs

All PN Offsets0

-20

98/05/24 23:14:09.817 [SCH]Sync Channel Message

MSG_LENGTH = 208 bits

MSG_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 strongestavailable PN, decode Walsh 32,

and read Sync Channel Message

SYNC CHANNEL MESSAGE


RF x

LO Srch PN??? W0

F1 PN168 W32

F2 PN168 W32

F3 PN168 W32

Th C fi ti M


57/137


The Configuration Messages

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

G t P i Ch l G t C fi d


58/137


Go to Paging Channel, Get Configured

Rake Fingers

Reference PN

Active Pilot

E

c/Io

00

32K512

ChipsPN

All PN Offsets0

-20

Keep Rake finger(s) on strongestavailable 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

LO Srch PN??? W0

F1 PN168 W01

F2 PN168 W01

F3 PN168 W01

T V I t t C fi ti M


59/137


Two Very Important Configuration Messages

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

PAM_SZ = 3 Access Channel FramesPersist Val for Acc Overload Classes 0-9 = 0Persist Val for Acc Overload Class 10 = 0Persist 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 MESSAGE98/05/24 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 = 0

HOME_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 = 1RESERVED = 0GLOBAL_REDIRECT = 0

SYSTEM PARAMETERS MESSAGE

F Additi l C fi ti M


60/137


Four Additional Configuration Messages

98/05/24 23:14:10.946 [PCH]Extended System Parameters MessageMSG_LENGTH = 104 bitsMSG_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 = 0RESERVED = 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 analogsystemAttempt 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 MessageMSG_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 IndexNGHBR_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 MessagePILOT_PN = 168 Offset IndexCONFIG_MSG_SEQ = 0CDMA_FREQ = 283RESERVED = Field Omitted

CDMA CHANNEL LIST MESSAGE


61/137


Lets do anIdle Mode Handoff!


Idl M d H d ff


62/137


Idle Mode Handoff

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, notsynchronous -- 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 isrequired, it re-registers on the new sector

Idle Mode on the Paging Channel:


63/137


g gMeet the Neighbors, track the Strongest Pilot

E

c/Io

All PN Offsets

00

32K512

ChipsPN

0

-20

Neighbor Set

The phones pilot searcher constantly checks

the 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 id le 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


64/137


Phone Operation on the Access Channel

A sectors Paging Channel announces 1(typ) to 32 (max) Access Channels: PN

Long 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 notyet under BTS closed-loop power control!

Phones access the BTS by probing atpower levels determined by receive powerand an open loop formula

If probe not acknowledged by BTSwithin 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 allrelated 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 FC

RV TFC

FW TFC

FW TFC

A Successful Access Attempt

a Probe Sequence

an Access Attempt

Success!

an Access Probe


65/137


Lets Register!


Registration


66/137


Registration

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 ofthe mobiles current location, so that incoming calls can bedelivered

registration also allows the system to intelligently page the

mobile 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


67/137


An Actual Registration

16:18:27.144 Access Channel: Registration

ACK_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]00-416-575-0421AUTH_MODE: 0REG_TYPE: Timer-basedSLOT_CYCLE_INDEX: 2MOB_P_REV: 1EXT_SCM: 1SLOTTED_MODE: 1MOB_TERM: 1

REGISTRATION MESSAGE

18:26.826 [PCH] System Parameters MessagePilot_PN: 32

CONFIG_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: 2

PWR_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] (134) 00-416-575-0421Order type: Base Station Acknowledgement Order

BASE STATION ACKNOWLEDGMENT

The System Parameters Message tells

all mobiles when they should register.This mobile notices that it is obligated to

register, so it transmits a RegistrationMessage.

The base station confirms that themobiles registration message wasreceived. Were officially registered!


68/137


Lets Receivean incoming Call!


Receiving an Incoming Call


69/137


Receiving an Incoming Call

All idle mobiles monitor the paging channel to receive incoming

calls. When an incoming call appears, the paging channel notifies the

mobile 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 iscompleted and the call proceeds.

An Actual Page and Page Response


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An Actual Page and Page Response

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 = 0IMSI_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 bits

MSG_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 = 6153300644SPECIAL_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 OrderADD_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 and


71/137


Traffic Channel Confirmation

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: 2CODE_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 on

the forward channel,usingthe assigned Walsh code.

The mobile sees at least two

good blank frames in a row onthe 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 acknowledgesreceiving the mobiles preamble.

The mobile station acknowledges thebase stations acknowledgment.

Everybody is ready!

Service Negotiation and Mobile Alert


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Service Negotiation and Mobile Alert

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: 0

USE_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 TrafficReverse Traffic Channel: Primary Traffic

SERVICE CONNECT MESSAGE

Now that both sides have arrived on the

traffic channel, the base stationproposes that the requested callactually begin.

The mobile agrees andsays its ready to play.

18:14:47.961 Forward Traffic Channel:Alert With InformationACK_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, andgives 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 Human Answers! Connect Order

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!


Placing an Outgoing Call


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Placing an Outgoing Call

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 a

base 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 Messageon 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.

Origination


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Origination

17:48:53.144 Access Channel: OriginationACK_SEQ: 7 MSG_SEQ: 6 ACK_REQ: 1VALID_ACK: 0 ACK_TYPE: 0 MSID_TYPE: 3

ESN: [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: 1DualMode: 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: 18008900829

NAR_AN_CAP: 0

ORIGINATION MESSAGE

17:48:53.487 Paging Channel: OrderACK_SEQ: 6 MSG_SEQ: 0 ACK_REQ: 0 VALID_ACK: 1

MSID_TYPE: 2IMSI: (Class: 0, Class_0_type: 0)[0x 03 5d b8 97 c2] 972-849-5073Base Station Acknowledgement Order


The mobile sends anorigination message

on the accesschannel.

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 bandCDMA_FREQ: 425

CHANNEL ASSIGNMENT MESSAGE

The base station sends aChannel Assignment

Message and the mobilegoes to the traffic channel.



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MOBILE STATION ACKNOWLEDGMENT17:48:54.757 Forward Traffic Channel: OrderACK_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 onthe 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 acknowledgesreceiving the mobiles preamble.

The mobile station acknowledges thebase stations acknowledgment.

Everybody is ready!

Service Negotiation and Connect Complete


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Service Negotiation and Connect Complete

17:48:55.137 Reverse Traffic Channel: Service Connect

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

SERVICE CONNECT MESSAGE

Now that the traffic channel is workingin 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 andthe two callers can talk!


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Lets End a Call!


Ending A Call


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Ending A Call

A normal call continues until one of the parties hangs up. That

action 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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A Beautiful End to a Normal Call

17:49:21.715 Reverse Traffic Channel: Order

ACK_SEQ: 1 MSG_SEQ: 1 ACK_REQ: 1ENCRYPTION: 0Release Order (normal release)

MOBILE RELEASE ORDER

BASE STATION ACKNOWLEDGMENT17:49:21.936 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, thismobile user pressed end.

The mobile left the traffic channel,

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

BASE STATION RELEASE ORDER17:49:21.997 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: 9600CDMA_FREQ: 425

SYNC CHANNEL MESSAGE

The base station acknowledgedreceiving the message, then senta release message of its own.


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Lets receive Notificationof a Voice Message!


Feature Notification


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Feature Notification

98/06/30 21:16:44.368 [PCH] Feature Notification MessageMSG_LENGTH = 144 bits

MSG_TYPE = Feature Notification MessageACK_SEQ = 0MSG_SEQ = 0ACK_REQ = 1VALID_ACK = 0

ADDR_TYPE = IMSIADDR_LEN = 56 bitsIMSI_CLASS = 0IMSI_CLASS_0_TYPE = 3RESERVED = 0MCC = 134

IMSI_11_12 = 00IMSI_S = 9055170325RELEASE = 0RECORD_TYPE = Message WaitingRECORD_LEN = 8 bitsMSG_COUNT = 1RESERVED = 0

FEATURE NOTIFICATION MESSAGE

The Feature Notification Message on

the 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!


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 MeasurementMessage to the system whenever triggered by:

It notices a pilot in neighbor or remaining setexceeds T_ADD

An active set pilot drops below T_DROP forT_TDROP time

A candiDate 2011pilot 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?


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y

E

c/Io

All PN Offsets

0

032K

512Chips

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/Ioabove T_ADD,

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

T_ADD

Rake Fingers

Reference PN

Active Pilot

10752

16832000

50014080

220

! !

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61

F2 PN168 W61F3 PN168 W61

Mobile Requests the Handoff!


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q

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 DisabledREF_PN = 168 Offset Index (the Reference PN)PILOT_STRENGTH = -6.0 dBKEEP = 1PILOT_PN_PHASE = 14080 chips (PN220+0chips)PILOT_STRENGTH = -12.5 dB

KEEP = 1PILOT_PN_PHASE = 32002 chips (PN500 + 2 chips)PILOT_STRENGTH = -11.0 dBKEEP = 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 168and 220.This pilot strength measurement messagereports PN 500 has increased above

T_Add, and the mobile wants to use it too.

The base station acknowledges receiving

the Pilot Strength Measurement Message.

System Authorizes the Handoff!


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y

98/05/24 23:14:02.926 [FTC] Extended Handoff Direction MessageMSG_LENGTH = 136 bits

MSG_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 chipsT_ADD = -13.0 dB T_DROP = -15.0 dB T_COMP = 2.5 dBT_TDROP = 4 secHARD_INCLUDED = 0FRAME_OFFSET = Field OmittedPRIVATE_LCM = Field OmittedRESET_L2 = Field OmittedRESET_FPC = Field OmittedRESERVED = Field Omitted

ENCRYPT_MODE = Field OmittedRESERVED = Field OmittedNOM_PWR = Field OmittedNUM_PREAMBLE = Field OmittedBAND_CLASS = Field OmittedCDMA_FREQ = Field OmittedADD_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

HANDOFF DIRECTION MESSAGE

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 useWalsh 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 Order

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


Mobile Implements the Handoff!


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p

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 Message

MSG_LENGTH = 72 bitsMSG_TYPE = Handoff Completion MessageACK_SEQ = 6 MSG_SEQ = 1 ACK_REQ = 1ENCRYPTION = Encryption Mode DisabledLAST_HDM_SEQ = 0PILOT_PN = 168 Offset IndexPILOT_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!


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g p , p

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 2011MessageMSG_LENGTH = 192 bits

MSG_TYPE = Neighbor List UpDate 2011MessageACK_SEQ = 1 MSG_SEQ = 7 ACK_REQ = 1ENCRYPTION = Encryption Mode DisabledPILOT_INC = 4 Offset IndexNGHBR_PN = 164 Offset IndexNGHBR_PN = 68 Offset IndexNGHBR_PN = 52 Offset IndexNGHBR_PN = 176 Offset IndexNGHBR_PN = 304 Offset IndexNGHBR_PN = 136 Offset IndexNGHBR_PN = 112 Offset Index

NGHBR_PN = 372 Offset IndexNGHBR_PN = 36 Offset IndexNGHBR_PN = 8 Offset IndexNGHBR_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

NEIGHBOR LIST UPDate 2011MESSAGE

In response to the mobiles HandoffCompletion Message, the base stationassembles a new composite neighborlist including all the neighbors of each ofthe three active pilots.This is necessary since the mobile

could be traveling toward any one ofthese pilots and may need to requestsoft handoff with any of them soon.

The mobile confirms receiving theNeighbor List UpDate 2011Message. 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!


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p g

Ec/Io

All PN Offsets

0

032K

512Chips

PN

0

-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

16832000

50014080

220

T_DROP

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61

F2 PN500 W50F3 PN220 W20

The Complete Picture of Handoff & Pilot Sets


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T_ADD

Ec/Io

All PN Offsets

00

32K512

ChipsPN

0

-20

Neighbor Set

SRCH_WIN_N

Active Set

CandiDate 2011SetT_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 W61F2 PN500 W50

F3 PN220 W20

Timing of Pilot Searchers Measurement Process


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The searcher checks pilots in nestedloops, much like meshed gears.Actives and candidatesoccupy the fastest-spinning wheel.Neighbors arenext, advancingone pilot for each

Act+Cand. revolution.Remaining is slowest,advancing one pilot eachtime the Neighbors revolve.

CURRENT PILOT SET CONTENTSA 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

3

112112

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 pi lots have been c hecked thu s far!

A

N

R

R

R

R

R

R

R

NN

N

N

NN

N N

A

A

Troubleshooting Call Events:S


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Watch Messaging, Mobile State

Your current capabilities

Earlier in this course we reviewed handset call processingstates

You have just seen the entire vocabulary of messagesordinarily 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 134

Handoff Perspective

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.

Which is better - 3-way or 6-way Soft Handoff?


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3 Way or 6 Way?

All handsets are capable of up to 6-way soft handoff

Nortel & Qualcomm networks allow up to 6-way soft-handoff

Lucent and Motorola networks allow only up to 3 way softhandoff

bug or feature?Advantage of 6-way: mobile does not depend on speedy

system reaction to handoff requests; this gives somewhatimproved dropped call rates in areas with extensive RFoverlap

Disadvantage: additional channel elements are used

Optional Network-Specific Handoff Features


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Ec/Io Handoff CandiDate 2011Screening

all networks rank the pilots reported by the mobiles, and incases where more candidates are proposed than the networkcan support in soft handoff, the soft handoff is set up using thebest N pilots

Some networks also screen candidates and apply a more

conservative theory when authorizing handoffs some networks use T_Comp as a secondary parameter to

implement hysteresis and prevent hyperactive handoffs

Some networks are experimenting with algorithms for dynamic,adaptive assignment of T_Add, T_Drop, and T_Comp

Nortel Handoff & Channel Allocation Features


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Inter-System Soft Handoff (ISSHO)

Soft handoff across SBS and MTX boundaries Multi-Carrier Traffic Allocation (MCTA)

Intelligent carrier selection during call setup

Soft Handoff Reduction Algorithm (SHORA)

Eliminating unneeded excessive soft handoff to improve capacity

Multi_Pilot Hard HandOff (MPHHO) Round-trip delay triggers, Pilot Beacon techniques

Enhanced Hard HandOff (EHHO)

Call quality triggers hard handoff when necessary

Multi-Mode Hard HandOff (MMHHO)

Sending capable CDMA mobiles between band classes or to analog

For more detail and latest improvements to all these features andalgorithms, take the Nort

CDMA Networks Intro

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Transcript of CDMA Networks Intro