CDMA TECHNOLOGY

INSTRCTOR: NAZILA SAFAVI

What This Course is All About?

CDMA

CDMA

ode

ivision

ultiple

ccess

What is Multiple Access?

Since the beginning of telephony and radio, system operators have tried to squeeze the maximum amount of traffic over each circuit

n Types of Media -- Examples: Twisted pair - copper Coaxial cable Fiber optic cable Air interface (radio signals)

n Advantages of Multiple Access Increased capacity: serve more users Reduced capital requirements since

fewer media can carry the traffic Decreased per-user expense Easier to manage and administer

Transmission

Medium

Each pair of users enjoys a dedicated,

private circuit through the transmission

medium, unaware that the other users exist.

Multiple Access: Simultaneous private use of a transmission medium by multiple, independent users.

What is a Channel?

The physical transmission medium is a resource that can be subdivided into individual channels according to different criteria depending on the technology used:

Here’s how the three most popular technologies establish channels:

FDMA Frequency Division Multiple Access each user on a different frequency a channel is a frequency

TDMA Time Division Multiple Access each user on a different window period in

time (“time slot”) a channel is a specific time slot on a

specific frequency CDMA Code Division Mult iple Access

each user uses the same frequency all the time, but mixed with different distinguishing code patterns

a channel is a unique code patternFrequency

Time

Power

FrequencyTime

Power

FrequencyTime

Power

FDMA

TDMA

CDMA

Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information

Defining Our Terms

n CDMA Channel or CDMA Carrier or CDMA Frequency Duplex channel made of two 1.25 MHz-wide bands of electromagnetic

spectrum, one for Base Station to Mobile Station communication (called the FORWARD LINK or the DOWNLINK) and another for Mobile Station to Base Station communication (called the REVERSE LINK or the UPNLINK)

in 800 Cellular these two simplex 1.25 MHz bands are 45 MHz apart in 1900 MHz PCS they are 80 MHz apart

n CDMA Forward Channel the 1.25 MHz Forward Link

n CDMA Reverse Channel the 1.25 MHz Reverse Link

n CDMA Code Channel each individual stream of 0’s and 1’s contained in either the CDMA

Forward Channel or in the CDMA Reverse Channel Code Channels are characterized (made unique) by mathematical codes code channels in the forward link: Pilot, Sync, Paging and Forward Traffic

channels code channels in the reverse link: Access and Reverse Traffic channels

45 or 80 MHz

CDMA CHANNELCDMA

ReverseChannel 1.25 MHz

CDMAForwardChannel 1.25 M Hz

Spread Spectrum Principles

Why do we call this a “Spread Spectrum” technique?

Spread Spectrum Payoff:Processing Gain

Spread SpectrumTRADITIONAL COMMUNICATIONS SYSTEM

SlowInformation

Sent

TX

SlowInformationRecovered

RX

NarrowbandSignal

SPREAD-SPECTRUM SYSTEM

FastSpreadingSequence

SlowInformation

Sent

TX

SlowInformationRecovered

RX

FastSpreadingSequence

WidebandSignal

n Traditional radio communication systems transmit data using the minimum bandwidth required to carry it as a narrowband signal

n Direct-Sequence Spread spectrum systems mix their input data with a fast spreading sequence and transmit a wideband signal The spreading sequence is

independently regenerated at the receiver and mixed with the incoming wideband signal to recover the original data

n The de-spreading gives substantial gain proportional to the bandwidth of the spread-spectrum signal

n The gain can be used to increase system performance and range, or allow multiple coded users, or both

CDMA Spreading Principle:Anything We Can Do, We Can Undo

n Any data bit stream can be combined with a spreading sequence

n The resulting signal can be de-spread and the data stream recovered if the original spreading sequence is available and properly timed

n After de-spreading, the original data stream is recovered intactNote - The spread sequences actually shown are icons, not accurate or to scale

ORIGINATING SITE DESTINATION

SpreadingSequence

SpreadingSequence

InputData

(Base Band)

RecoveredData

(Base Band)

Spread Data Stream(Base Band + Spreading Sequence)

Shipping and Receiving” via CDMA

n Whether in shipping and receiving, or in CDMA, packaging is extremely important!

n Cargo is placed inside “nested” containers for protection and to allow addressing

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

n CDMA “containers” are spreading codes

FedEx

Data Mailer

FedEx

DataMailer

Shipping Receiving

CDMA Spreading Principle:Multiple Successive Spreadings are

Reversible

n Multiple spreading sequences can be applied in succession and then reapplied in opposite order, to recover the original un-spread data streamthe spreading sequences can have different desired properties

n All spreading sequences originally used must be available in proper synchronization at the recovering destinationNote - The spread sequences actually shown are icons, not accurate or to scale

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

How Many Spreading Sequences Do We Need?(Discriminating Among Forward Code Channels

n A Mobile Station, tuned to a particular CDMA frequency, receives a Forward CDMA Channel from a sector in a Base Station.

n This Forward CDMA Channel carries a composite signal made of up to 64 “forward code channels”

n Some of these code channels are “traffic channels” while other are “overhead channels” needed by the CDMA system to operate properly.

n A set of 64 mathematical codes is needed to differentiate the 64 possible forward code channels that can be contained in a Forward CDMA Channel. The codes in this set are called “Walsh Codes”

SyncPilot

FW Traffic(for user #1)

Paging

FW Traffic(for user #2)

FW Traffic(for user #3)

How Many Spreading Sequences Do We Need?(Discriminating Among Base Station

n A mobile Station is surrounded by Base Stations, all of them transmitting on the same CDMA Frequency

n Each Sector in each Base Station is transmitting a CDMA Forward Traffic Channel containing up to 64 distinct forward code channels

n A Mobile Station must be able to discriminate between different Sectors of different Base Stations and listen to only one set of code channels

n Two binary digit sequences called the I and Q Short PN Sequences (or Short PN Codes) are defined for the purpose of identifying sectors of different base stations

n These Short PN Sequences can be used in 512 different ways in a CDMA system. Each one of them constitutes a mathematical code which can be used to identify a particular sector of a particular base station

A B

Up to 64Code Channels

Up to 64Code Channels

How Many Spreading Sequences Do We Need?(Discriminating Among Reverse Code Channels

n The CDMA system must be able to uniquely identify each Mobile Station that may attempt to communicate with a Base Station

n A very large number of Mobile Stations will be in the market

n One binary digit sequence called the Long PN Sequence (or Long PN Code) is defined for the purpose of uniquely identifying each possible reverse code channel

n This sequence is extremely long and can be used in trillions of different ways. Each one of them constitutes a mathematical code which can be used to identify a particular user (and is then called a User Long Code) or a particular “access channel” (explained later in this course)

RV Trafficfrom M.S.

#1837732008RV Trafficfrom M.S.

#8764349209

RV Trafficfrom M.S.

#223663748

System AccessAttempt by M.S.

#4348769902(on access channel #1)

CDMA Magic Spreading Tool #1:Walsh Codes

n 64 “Magic” Sequences, each 64 chips long a chip is a binary digit (0 or 1)

n Each Walsh Code is Orthogonal to all other Walsh Codes

this means that it is possible to recognize and therefore extract a particular Walsh code from a mixture of other Walsh codes which are “filtered out” in the process

n Two same-length binary strings are orthogonal if the result of XORing them has the same number of 0s as 1s

WALSH CODES # --- ------ ------ ------- ------ ------ 64- Ch ip Sequence -- ------ ------- ------ ------ ------- ------ --

0 0000000000000000000000000000000000000000000000000000000000000000

1 0101010101010101010101010101010101010101010101010101010101010101 2 0011001100110011001100110011001100110011001100110011001100110011 3 0110011001100110011001100110011001100110011001100110011001100110 4 0000111100001111000011110000111100001111000011110000111100001111 5 0101101001011010010110100101101001011010010110100101101001011010

6 0011110000111100001111000011110000111100001111000011110000111100 7 0110100101101001011010010110100101101001011010010110100101101001 8 0000000011111111000000001111111100000000111111110000000011111111 9 010101011010101001010101101010100101010110101010010101011010101010 0011001111001100001100111100110000110011110011000011001111001100

11 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 0110100110010110011010011001011001101001100101100110100110010110

16 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 0000111100001111111100001111000000001111000011111111000011110000

21 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 0101010110101010101010100101010101010101101010101010101001010101

26 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 0011110011000011110000110011110000111100110000111100001100111100

31 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 0110011001100110011001100110011010011001100110011001100110011001

36 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 0000000011111111000000001111111111111111000000001111111100000000

41 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 0101101010100101010110101010010110100101010110101010010101011010

46 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 0011001100110011110011001100110011001100110011000011001100110011

51 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 0110100101101001100101101001011010010110100101100110100101101001

56 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 0000111111110000111100000000111111110000000011110000111111110000

61 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

EXAMPLE:

Correlation of Walsh Code #23 with Walsh Code #59

#23 0110100101101001100101101001011001101001011010011001011010010110#59 0110011010011001100110010110011010011001011001100110011010011001

XOR 0000111111110000000011111111000011110000000011111111000000001111

Correlat ion Results: 32 1’s, 32 0’s: Orthogonal!!

Note: Example of orthogonality – The coordinates used to describe the position of a mobile station at a certain time: latitude (North or South of the Equator), longitude (East or West of Greenwich), altitude (relative to sea level), and time. A change in any of these magnitudes does not affect the other three, therefore they are “orthogonal”.

Correlation and Orthogonality

Correlation is a measure of the similarity between two binary strings

Code #23 0110100101101001100101101001011001101001011010011001011010010110

-(Code #23) 1001011010010110011010010110100110010110100101100110100101101001

Code #59 0110011010011001100110010110011010011001011001100110011010011001

PARALLEL

XOR: all 0s

Correlation: 100%(100% match)

ORTHOGONAL

XOR: half 0s, half 1s

Correlation: 0%(50 % match, 50% no-match)

ANTI-PARALLEL

XOR: all 1s

Correlation: -100%(100% no-match)

#23#23

-(#23)

#23

#23

#59

-(#23)

CDMA Magic Spreading Tool #2:The Short PN Sequences

n The two PN Sequences, I and Q, are 32,768 chips longTogether, they can be

considered a two-dimensional binary “vector” with distinct I and Q component sequences, each 32,768 chips long

n Each Short PN Sequence (and, as a matter of fact, any sequence) correlates with itself perfectly if compared at a timing offset of 0 chips

n Each Short PN Sequence is special: Nearly orthogonal to a copy of itself that has been offset by any number of chips (other than 0)

IQ

32,768 chips long26 2/3 ms.

(75 repetitions in 2 sec.)

IQIQ

100% Correlation: All bits = 0

Short PN Sequence vs. Itself @ 0 Offset

IQIQ

Orthogonal: 16,384 1’s + 16,384 0’s

Short PN Sequence vs. Itself @ Any Offset

Unique Properties:

CDMA Magic Spreading Tool #3:The Long PN Sequence (User Long Code)

n Each mobile station uses a world-unique User Long Code Sequence generated by applying a mask, based on its 32-b it ESN, to the 42-bit Long Code Generator which was synchronized with the CDMA system during the mobile station initialization

n Generated at 1.2288 Mcps, this sequence requires 41 days, 10 hours, 12 minutes and 19.4 seconds to complete

n Portions of the Users Long Codes generated by different mobile stations for the duration of a call are not exactly orthogonal but are sufficiently different to permit re liable decoding on the reverse link

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 PERMUTED ESNAND

=SUM

Modulo-2 Addition

CDMA Code Channels in the Forward Direction

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

does not contain a c haracter stream. It is a timing source used in system acquisition and as a measurement device during handoffs

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

identification and parameter information used by mobiles during sy stem acquisition

n 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 parameters information, and call setup orders

n TRAFFIC: any remaining WALSH codes The traffic channels are as signed to

individual users to c arry call traffic. All remaining W alsh codes are available, subject to ove rall 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

Coding Process on CDMA Forward Code Channels

MTX BSC BTS (1 sector)

FECWalsh #1

Sync FECWalsh #32

FECWalsh #0

FECWalsh #12

FECWalsh #23

FECWalsh #27

FECWalsh #44

Pilot

Paging

Vocoder

Vocoder

Vocoder

Vocoder

more more more

Short PN CodePN Offset 246

Trans-mitter,

Sector X

I Q

A Forward Channel is identified by:

v its CDMA RF carrier Frequency

v the unique Short Code PN Offset of the sector

v the unique Walsh Code of the user

MSC

CDMA Code Channels in the Reverse Direction

There are two types of CDMA Reverse Channels:

n TRAFFIC CHANNELS are used by individualusers during their actual calls to transmit trafficto 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

n ACCESS CHANNELS are used by mobile stations not yet in a call to transmit registration requests, call setup requests, page responses, order responses, and other signaling information

• an access channel is defined by a user-independent public long code mask

• Access channels are paired with Paging Channels. There can be up to 32 access channels per paging channel

BTS

REG

1-800242

4444

Coding Process on CDMA Reverse Code Channels

MTX BSC BTS (1 sector)

Channel Element

Access Channels

Vocoder

Vocoder

Vocoder

Vocoder

more more

Receiver,Sector X

A Reverse Channel is identified by:

v its CDMA RF carrier Frequency

v the unique Long Code PN Offset of 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

LongCode Long

CodeLongCode

LongCode

LongCode

LongCode

MSC

CDMA’s “Magic” Spreading SequencesSummary of Characteristics & Functions

n Each CDMA spreading sequence is used for a specific purpose on the forward link and a different purpose on the reverse link

n The sequences are used to form “code channels” for users in both directions

Cell

Walsh Codes

Short PN Sequences

Long PN Sequence

Type of Sequence

Mutually Orthogonal

Near orthogonal with itself

a t any chip offset

except 0

se ctions of it a re near-orthogonal

Special Properties

64

2

1

How Many

64 chips1/19,200

sec.

32,768 chips

26-2/3 ms75x in 2

sec.

242 chips~41 days

Length

Information Carrier

supe r-reliable“Trojan horse”

Quadra ture Spreading

(Zero offset)

Data Scrambling &

Disti nguish us ers

Reverse Link

Funct ion

User ide nti ty

within cel l’s s ignal

Distinguish C ells,

Sectors & Quadrature Spreading

Data Scrambling to avoid all 1’s or 0’s

Forward Link

Function

IQ

32,76 8 chips long26-2/3 ms.

(75 repetit ions in 2 sec.)

64codes

64 chips long

AND

=M odulo-2 A ddition

Basic Spreading & De-spreading Example:User’s Data Spread, Sent, Recovered

At Originating Site:n Input A: User’s Data @

19,200 bits/second

n Input B: Walsh Code #23 @ 1.2288 Mcps

n Output: Spread spectrum signal

At Destination Site:n Input A: Received

spread spectrum signal

n Input B: Walsh Code #23 @ 1.2288 Mcps

n Output: User’s Data @ 19,200 bits/second just as originally sent Drawn to actual scale and time alignment

via air interface

XORE xclusive-O R

Gate

1

Input A: Received Signal

Input B: Spreading Code

Output: User’s Original Data

Input A: User’s Data

Input B: Spreading Code

Spread Spectrum Signal

XORE xclusive-O R

G ate

Originating Site

Destination Site

1

Spectrum Usage and System Capacity:Signal Bandwidth, Vulnerability, and Frequency Reuse

n Each wireless technology (AMPS, NAMPS, D-AMPS, GSM, CDMA) uses a specific modulation type with its own unique signal characteristics

n The total traffic capacity of a wireless system is determined largely by radio signal characteristics and RF design

n RF signal vulnerability to Interference dictates how much interference can be tolerated, and therefore how far apart same-frequency cells must be spaced

n For a specific S/N level, the Signal Bandwidth determines how many RF signals will “fit” in the operator’s licensed spectrum

AMPS, D-AMPS, N-AMPS

CDMA

30 30 10 kHz

200 kHz

1250 kHz

1 3 1 Users

8 Users

22 Users1

1

11

1

11

11

1

11

1

1

12

34

4

32

56

17

Typical Frequency Reuse N=7

Typical Frequency Reuse N=4

Typical Frequency Reuse N=1

Vulnerability:C/I 17 dB

Vulnerability:C/I 12-14 dB

Vulnerability:Eb/No 6 dB

GSM

17 dB = 101.7 50

14 dB = 101.4 25

12 dB = 101.2 16

Relationship Between Eb/N0 And S/N

Eb =S

R

Signal Power

Bit Rate = N0 =

N

W

Noise Power

Bandwidth=

=S

R

W

N X =

S

N

W

R X

S

R

N

W

Eb

N0

=

Signal to Noise

ProcessingGain

E / t

B / t=

W

R1,250,000

14,400 87 1.9410 19 dB

W

R1,250,000

9,600130 2.1110 21 dB8 Kb vocoder

(Full Rate)

13 Kb vocoder(Full Rate)

CDMA Advantage (13 kb vocoder at full rate)

AMPS

N-AMPS

D-AMPS

GSM

CDMA

Analog FM

Analog FM

DQPSK

GMSK

QPSK/OQPSK

30 KHz.

10 KHz.

30 KHz.

200 KH z.

1,250 K Hz.

C/I 17 dB

C/I 17 dB

C/I 17 dB

C/I 12-14 dB

Eb/N

o 6dB

Tech-nology Modulat ion Type

Channel Bandwidth

QualityIndicator

S/N 17 dB

S/N 17 dB

S/N 17 dB

S/N 12 to 14 dB

S/N –13dB

S/N

17 dB = 101.7 5014 dB = 10 1.4 25

12 dB = 10 1.2 16-13 dB = 10 -1.3 = 0.05 ~

S

N

10 0.6

10 1.9= = 10 -1.3= -13 dB

Signal to NoiseProcessing Gain (W/R)

S

NX = 10 0.610 1.9

Eb N0

Reverse Link Interference Scenarios

n AMPS, N-AMPS, TDMA, and GSM systems do not use spreading. Co-channel users must be separated by distance to achieve the desired C/I ratio. Interferors are co-channel

users in distant cellsn CDMA systems use spreading and

due to their spreading gain can tolerate negative C/I.Many co-channel users can

share the same cell!However, this requires that

all users be power-controlled so their signals reach the base station at the same signal level

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

CDMA

usersTight Reverse-Link Power

Control is essential in CDMA

CDMA Capacity Considerations

60 %

6%

6 %

6%

6%

6%

6%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%0.2%

0.2%

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 % 0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 03 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 % 0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %

1 X 60 = 60

6 X 6 = 36

12 X 0.2 = 2.4

18 X 0.03 = 0.54

24 X 0.01 = 0.24

TOTAL = 99.18 %

80 %

1 %

1 %

6 %

6 %

1 %

1 %

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.2%

0.1%

0.1%

0.1%0.1%

0.1%

0. 01 %

0. 01 %

0. 03 %

0. 01 %

0. 01 %

0. 01 %

0. 01 %0. 01%

0. 01 % 0. 01 %

0. 01 %

0. 00 %

0. 00 %

0. 01 %

0. 00 %

0. 00 %

10 0%

RURAL AREA

URBAN AREA

NEAR A HIGHWAY

Coexistence of CDMA with Other Systems

n Guard bands are needed between CDMA and other systems because CDMA increases the noise floor for those systems.

n These systems appear as noise for the CDMA system.

n No guard band is needed between adjacent CDMA systems.

260 kHzGuard Band

260 kHzGuard Band

Frequency

Power 1.77 MHz

1.25 MHzCDMA Carrier

Overlaying CDMA on an AMPS System

CDMA

1770 ÷ 30 = 59

1250 ÷ 30 = 41.7

260 ÷ 30 = 8.7

260 kHz 260 kHz1.25 M Hz No minal Bandw idth

Frequency

Power

1.77 MH z

CDMA CARRIER

n All frequencies are available for AMPS use

n Only the frequencies in the purple area are available for AMPS use

CDMA 800 MHz Cellular Spectrum Usage

n All CDMA RF carriers are 1.25 MHz. wide can serve ~22 users w/8 kb vocoder (~17 users w/13 kb vocoder)

n The cellular spectrum of one operator is 12.5 MHz. wide. You’d expect that 10 CDMA carriers would fit. However, only 9 carriers can be used operators must maintain a “token” AMPS presence for several years “guard bands” are required at the edges of frequency blocks or any

frequency boundaries between CDMA/non-CDMA signals no guard bands are required between adjacent CDMA carriers

Possible CDM A

Center Freq. As signments

Channel Numbers

Forward l ink (i.e ., cell site transmits)Rev erse link (i.e., mobile trans mits)824MHz

8 49M Hz

869MHz

8 94M Hz

otheruses

A” A”A B A’ B’

1 10 10 1.5 2.5

A B A’ B’

1 10 10 1.5 2.5

9 9110231 33 3334 666667 716717 79 9 99110231 3 33334 66 666 771 671 7 7 99

~300 kHz. “gua rd bands ” possibly required if a dja cent-

freque nc y signa ls are non-CDMA (AMPS, TDM A, ES MR, etc. )

CDMA 800 MHz Cellular Spectrum Usage

Order Side “A” Side “B”

1 283 384

2 242 425

3 201 466

4 160 507

5 119 548

6 78 589

7 37 630

8 1019 777

9 691 736

The above table is an example of CDMA channel allocation, in chronological order, which allows maximum CDMA channel packing.

Note: a) requires frequency coordination with non-cellular interferes

b) requires frequency coordination with A-side carrier

Deploying CDMA on the 1900 MHz band

CDMA

1770 ÷ 50 = 35.4

1250 ÷ 50 = 25

260 ÷ 50 = 5.2

260 kHz 260 kHz1.25 MHz Nominal Bandwidth

Frequency

Power

1.77 MHz

CDMA CARRIER

n All frequencies are available for non-CDMA use

n Only the frequencies in the blue area are available for non CDMA use

CDMA PCS 1900 MHz Spectrum Usage

n A, B, and C licenses can accommodate 11 CDMA RF channels in their 30 MHz of spectrum

n D, E, and F licenses can accommodate 3 CDMA RF channels in their 10 MHz of spectrum

n 260 kHz guard bands are required on the edges of the PCS spectrum to ensure no interference occurs with other applications just outside the spectrum

Gua rd B ands

Forwa rd li nk (i.e., cell s ite transmits )Reve rse link (i.e., mobi le tra nsmits)1 850 MHz

BTA

BTA

BTA

BTA

BTA

BTA

Paired Bands

MTA B TAMTAB TA MTAM TA

19 10 M Hz

1930MHz

1 990M Hz

D ata Voice

A D B E F C A D B E F C

15 5101 0 1 515151 515 555 55

LicensedLicensed

Unlicense d

0

Channel Numbe rs

299300 400 69 97 00 80 0 90 0 11990

29 93 00 400 699700 8 00 900 119 9

CDMA PCS 1900 MHz Spectrum Usage

1 25

2 50

3 75

4 100

5 125

6 150

7 175

8 200

9 225

10 250

11 275

493 BTAs (Basic Trading Areas) are grouped into 51 MTAs (Metropolitan Trading Area s).

The following tables are examples of CDMA channel allocation, in chronological order, which allow maximum CDMA channel packing. Each table represents the “preferred” set of CDMA channels according to J-STD-008.

PCS Band A

1 25

2 50

3 75

4 100

5 125

6 150

7 175

8 200

9 225

10 250

11 275

1 25

2 50

3 75

4 100

5 125

6 150

7 175

8 200

9 225

10 250

11 275

1 325

2 350

3 375

PCS Band B PCS Band C

PCS Band D

1 725

2 750

3 775

1 825

2 850

3 875

PCS Band E

PCS Band F