An Overview of cdma2000 Technology Concepts · 2004-07-21 · An Overview of cdma2000 Technology...

presented by:

Ken Carolus

An Overview of cdma2000 Technology ConceptsAn Overview of cdma2000 Technology Concepts

June 24, 2002 and July 16, 2002

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An Overview of cdma2000 Technology ConceptsAn Overview of cdma2000 Technology Concepts

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• Review of IS-95 CDMA Concepts• cdma2000 Improvements• cdma2000 Concepts• cdma2000 Network Architecture

ContentsContents


Cellular Access MethodsCellular Access Methods

Power

Frequency

Time

FDMA

Frequency

Power Time

TDMA

Frequency

CDMA

PowerTime


CDMA is Also Full DuplexCDMA is Also Full Duplex

US Cellular Channel 384

Frequency

Amplitude

Frequency

Amplitude

AMPS

45 MHz(80 MHz PCS)

Forward Link

881.52 MHz836.52 MHz

Reverse Link

CDMA

45 MHz

836.52 MHz 881.52 MHz

Reverse Link Forward Link


Cellular Frequency Reuse PatternsCellular Frequency Reuse Patterns

CDMA Reuse FDMA Reuse

1

11

1

1

11

11

1

3

6

2

62

2

1

45

7


The CDMA ConceptThe CDMA Concept

Interference Sources

Walsh CodeSpreading

Encoding &Interleaving

Walsh CodeCorrelator

Decode &Deinterleaving

BasebandData

BasebandData

Background Noise

External Interference

Other Cell Interference

Other User Noise

9.6 kbps 19.2 kbps 1228.8 kbps 1228.8 kbps 19.2 kbps 9.6 kbps

Transmitter Receiver

1.25 MHz BW

fc

1.25 MHz BW

fc

10 kHz BW

0

10 kHz BW

0

1.25 MHz BW

fc

1.25 MHz BW

fcfc

-103 dBm/1.23 MHz

fc

Spurious Signals


IS-2000 Terms and definitionsIS-2000 Terms and definitions• Chip

• Is the period of a data bit at the final spreading rate

• SR - Spreading Rate• Defines the final spreading rate in terms of

1.2288 Mcps.• RC - Radio Configuration

• Defines the physical channel configuration based upon a base channel data rate.

• RCs contain rates derived from their base rate. For example, RC3 is based on 9.6 kbps and includes 9.6, 19.2, 38.4, 76.8, and 153.6 kbps.


What is Correlation?What is Correlation?

• Is a Measure of How Well a Given Signal Matches a Desired Code

• The Desired Code is Compared to the Given Signal at Various Test Times

Received Signal

Correlation = 1

Correlation = 0

Correlation = 0

Correlation = 0


Spatial Diversity During Soft HandoffSpatial Diversity During Soft Handoff

MTSO

Vocoder / Selector

Base Station 2Base Station 1

Land Link


CDMA Frequency DiversityCDMA Frequency DiversityCombats Fading, Caused by Multipath

Fading Acts like Notch Filter to a WideSpectrum Signal

May Notch only Part of Signal

Amplitude

Frequency

1.25 MHz BW


CDMA Time DiversityCDMA Time Diversity

Uses Rake Receiver

Convolutional Encoding

Data is Interleaved

Viterbi Decoding


The Rake ReceiverThe Rake Receiver

Time

Frequency

Amplitude


Power ControlPower Control

Near-far effect: BS receiver captured by nearby MS

• Important in cdma systems because of frequency reuse of N=1

• The goal is to maintain equal received power at the base station from each mobile

• Affects traffic channels (not pilot signal)


CDMA Power Control (Reverse Link)CDMA Power Control (Reverse Link)

All Mobiles are Received at Base Station at Equal Power

Two Types of Control

Open Loop Power Control

Closed Loop Power Control


Open Loop Power Control (Reverse Link)Open Loop Power Control (Reverse Link)

Assumes Loss is Similar on Forward and Reverse Paths.

Receive Power+Transmit Power = -73All powers in dBm

Example:For a Received Power of -85 dBm (at the mobile)

Transmit Power = (-73) - (-85) Transmit Power = +12 dBm


Closed Loop Power Control (Forward & Reverse)Closed Loop Power Control (Forward & Reverse)

Directed by Base Station (for the Reverse Link) and by Mobile (for the Forward Link)

Updated Every 1.25 msec

1 dB Step Size (also 0.25 and 0.5 dB)

Closed Loop Adds to Open Loop PowerEstimate on Reverse Link


Forward Link Traffic Channel IS-95 Physical LayerForward Link Traffic Channel IS-95 Physical Layer

WalshCover

I Short Code

Q Short Code

FIR

FIR1.2288Mbps

Walsh Code Generator

I

1.2288Mbps

1.2288 Mbps

1.2288 Mbps

Long Code

19.2 kbps

19.2 kbps

Vocoded Speech data

20 msec blocks

Interleaver

Power ControlPuncturing

19.2 kbps

19.2 kbps

800 bps

800 bps

P.C.MUX

9.6 kbps

19.2 kbps

3/4 rate

1/2 rate

14.4 kbps

19.2 kbps

ConvolutionalEncoder

Long CodeScrambling

Short Code Scrambler

Q


Code Domain Power (IS-95)Code Domain Power (IS-95)

Frequency Domain

User #2User #1

SynchPaging

Pilot

1.2288 MHzfreq

Code Domain

0 1 2 3 4 5 6 7 8 9 32 40 63User

1User

3User

2

Walsh Code

Pilot Paging Synch

User #3


ContentsContents



IS-2000 Improvements vs. IS-95IS-2000 Improvements vs. IS-95• 2X Voice Capacity

• Reverse Link Pilot for Each Mobile

• Fast Forward (new) and Reverse Link Power Control

• QPSK Modulation

• Improved Convolutional Channel Encoding for 14.4 kbps Voice Channels

• Supports Auxiliary Pilots for Beam Forming, Multi-Antennas, and many other options


cdmaOne to cdma2000 1xRTTcdmaOne to cdma2000 1xRTT• 1xRTT keeps same chip rate and carrier bandwidth• Splits the data into I and Q (QPSK Modulation vs. P-BPSK) • Keep existing IS-95-based channels for backwards

compatibility with IS-95 mobiles• IS-95B enhancements retained

• Adds new radio configurations, adds new FWD and REV channels• New optional control channels• New fundamental traffic channels• New supplemental traffic channels for faster data• New turbo codes and spreading techniques

• ∼35 max users/sector/carrier for IS-95, ∼70 max for IS-2000


cdma2000 to Achieve 3G Data Rates (cont.)cdma2000 to Achieve 3G Data Rates (cont.)

IS-95A/J-Std008

IS-95B

1xRTT

3xRTT

Technology Data CapabilitiesUp to 14.4 kbps using one traffic channel for supplemental data

Up to 115.2 kbps using 1 traffic channel and up to 7 supplemental code channels supporting 14.4 kbps each

Up to 153.6 kbps (RC3) or 307.2 kbps (RC4) per SCH (one deployed today); RC3 avail. today; Uses fundamental & supplemental channels, advanced rate and QoS managementUp to 1.0386 Mbps (RC9) using fundamental channel for voice and supplemental channel(s) for data; 2 Mbps using 2 SCH

•New transmission modes offer faster data rates

•1xEV-DO and 1xEV-DV: 2.4 Mbps and higher


The CDMA Technology Path to 3GThe CDMA Technology Path to 3GcdmaOne cdma2000/IS-2000

Technology

Generation

SignalBandwidth,

#Users

Features:Incremental

Progress

1G

AMPS

DataCapabilities

30 kHz.1

First System,Capacity

&Handoffs

None,2.4K by modem

2G

IS-95A/J-Std008

1250 kHz.20-35

First cdma,Capacity,Quality

14.4K

2G

IS-95B

1250 kHz.25-40

•Improved Access

•Smarter Handoffs

64K

2.5G or 3

IS-2000:1xRTT

1250 kHz.50-80 voice

and data

•Enhanced Access

•Channel Structure

153K307K230K

3G

1xEV-DO/DV

1250 kHz.Many packet

users

Faster data rates on 1x

carrier

2.4 Mb/s(1xEV-DO)

3.864 Mb/s(1xEV-DV)

3G

IS-2000:3xRTT

F: 3x 1250kR: 3687k

120-210 per 3 carriers

Faster data rates on

shared 3-carrier bundle

2.0 Mb/s


Differences Between W-CDMA and cdma2000Differences Between W-CDMA and cdma2000

W-CDMA cdma2000

New Spectrum only Overlay IS-95

3.84 Mcps 1.2288 Mcps

New equipment Upgrade existing

3GPP 3GPP2


ContentsContents



IS-95A/B (9.6 kbps)IS-95A/B (9.6 kbps)Traffic Channel (F-FCH)

*Short Code Scrambler

64 Walsh CodeGenerator

1228.8 kcps

Q Short Code

Q

I

FIR

FIR

I Short CodeIS-95B

* Parallel BPSK


IS-2000 SR1, RC3 (9.6 kbps) (cont.)IS-2000 SR1, RC3 (9.6 kbps) (cont.)

Traffic Channel (F-FCH)

OptionalCan be Carried by F-DCCH

8.6 kbps

1228.8 kbps

Long CodeDecimator

Interleaver

38.4 ksps

1/4 Rate Conv.Encoder

38.4 ksps

9.6 kbps

Long CodeGenerator

38.4 kbps

PowerControlPuncture

Walsh 64Generator

1228.8 kcps

1228.8 kcps

1228.8 kbps

1228.8kbps

Q

I

S -P

800 bps

PCUser LongCode Mask

Q

I

PCDec

1228.8 kcps

Q Short Code

I

Q

1228.8 kcps

ComplexScrambling

I

FIR

FIRI Short Code

OrthogonalSpreading

1228.8 kcps

1228.8 kcps

+

+

+

-

38.4 ksps

19.2 ksps

19.2 ksps

P.C. Bits

Decimate by Walsh Length/2

Gain

Gain

PunctureTiming

Full RateData Bits

Add CRC andTail Bits

800 bps

Q


Forward Common PilotForward Common Pilot

19.2 ksps

Walsh 128Generator

1228.8 kcps

1228.8 kcps

1228.8 kbps

1228.8kbps

Q

I

Q

I

1228.8 kcps

Q Short Code

I

Q

1228.8 kcps

ComplexScrambling

Q

I

FIR

FIRI Short Code

1228.8 kcps

1228.8 kcps

+

+

+

-

OrthogonalSpreading

All 0’s

• Equivalent to IS-95 pilot (Walsh 0 with chip offsets identifying BSs)

• 512 total PNs with 64-chip offsets

• Provides synchronism, signal measurements and phase reference

• Pilot, Paging, Sync applied only to in-phase channel


Creating a Walsh Code MatrixCreating a Walsh Code Matrix

[ ]01 =W

=

11

112 WW

WWW

=

22

224 WW

WWW

=

nn

nnn WW

WWW2. . .

0 00 0000 0000000001 0101 01010101

0011 001100110110 01100110

00001111010110100011110001101001

W1 W2 W4 W8

ExampleReferencing Walsh Codes

W4[2] = 0011W8[7] = 01101001W2[0] = 00

87w = Walsh Set 8

Walsh Code 7


IS-2000 Walsh Code TreeIS-2000 Walsh Code TreeHadamard Sequence

Walsh 2 Walsh 4 Walsh 8

1 1 1 1 1 1 1 1

1 -1 1 -1 1 -1 1 -1

1 1 -1 -1

1 1 1 11 1

1 -1 1 -1 1 -1

1 -1 -1 1

1

1 1 1 1 -1 -1 -1 -1

1 -1 1 -1 -1 1 -1 1

1 1 -1 -1 -1 -1 1 1

1 -1 -1 1 -1 1 1 -1

1 -1 -1 1 1 -1 -1 1

1 1 -1 -1 1 1 -1 -1

0

1

0

1

2

3

0

1

2

3

4

5

6

7

SF=2 SF=4 SF=81 1 1 1 1 1 1 1

1 1 1 1 -1 -1 -1 -1

1 1 -1 -1

1 1 1 1

1 1

1 -1

1 -1 1 -1

1 -1 -1 1

1 1 -1 1 -1 1 -1 1 -1

1 -1 1 -1 -1 1 -1 1

1 -1 -1 1 1 -1 -1 1

1 -1 -1 1 -1 1 1 -1

1 1 -1 -1 -1 -1 1 1

1 1 -1 -1 1 1 -1 -10

1

0

2

1

3

0

4

2

6

1

5

3

7

Bit Reversed SequenceWalsh Set 2 Walsh Set 4 Walsh Set 8


Effects of Using Variable Length Walsh CodesEffects of Using Variable Length Walsh Codes

SF=16SF=2 SF=4 SF=8

1 1 1 1 1 1 1 1

1 1 1 1 -1 -1 -1 -1

1 1 -1 -1

1 1 1 1

1 1

1 -1

1 -1 1 -1

1 -1 -1 1

1

1 -1 1 -1 1 -1 1 -1

1 -1 1 -1 -1 1 -1 1

1 -1 -1 1 1 -1 -1 1

1 -1 -1 1 -1 1 1 -1

1 1 -1 -1 -1 -1 1 1

1 1 -1 -1 1 1 -1 -1

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 -1 -1 -1 -1 -1 -1 -1 -1

1 1 1 1 -1 -1 -1 -1 1 1 1 1 -1 -1 -1 -1

1 1 1 1 -1 -1 -1 -1 -1 -1 -1 -1 1 1 1 1

1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1

1 1 -1 -1 1 1 -1 -1 -1 -1 1 1 -1 -1 1 1

1 1 -1 -1 -1 -1 1 1 1 1 -1 -1 -1 -1 1 11 1 -1 -1 -1 -1 1 1 -1 -1 1 1 1 1 -1 -1

1 -1 1 -1 1 -1 1 -1 1 -1 1 -1 1 -1 1 -1

1 -1 1 -1 1 -1 1 -1 -1 1 -1 1 -1 1 -1 1

1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1

1 -1 1 -1 -1 1 -1 1 -1 1 -1 1 1 -1 1 -1

1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1

1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1

1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1

1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1

WalshSet 2

WalshSet 4

WalshSet 8

WalshSet 16• Logical 1’s and 0’s

can be represented as physical -1’s and 1’s in the modulation domain

• Shorter Codes on a Branch map into Longer Codes

• Using Shorter Walsh Codes Precludes Using all Longer Codes Derived from the Original

0

2

1

3


Orthogonality of Walsh CodesOrthogonality of Walsh Codes

• Walsh codes are:

• Orthogonal with each other and their inverses:• Orthogonality = Equal

Number of Matches and Mismatches

1 1 1 1 1 1 1 1

1 -1 -1 1 1 -1 -1 1

Walsh Codes with SF=8

Matches = 4

Mismatches = 4

Net Correlation = 0

Match? Y N N Y Y N N Y

Code

Code


IS-2000 Walsh Code Tree (Top Half)IS-2000 Walsh Code Tree (Top Half)WalshSet #1

Walsh Set #2

WalshSet #4

WalshSet # 8

Set # 32 Set # 64 Walsh Set # 128

28

24

40

20

0

32

16

48

8

56

4

36

52

12

44

60

2

34

18

50

10

42

26

58

54

14

46

30

6212662

94

11046

78

11854

86

10238

70

12258

90

10642

74

11450

82

9834

66

12460

92

10844

76

1165284

10036

68

12056

88

10440

728

24

4

20

12

28

2

18

10

26

6

22

14

30

6

38

22

0

16

8

24

4

20

12

28

2

18

10

26

6

22

14

30

Set #16

0

8

4

12

2

10

6

14

0

4

2

6

0

2

0

0

064

3296

1680

48112


IS-2000 Forward Radio ConfigurationsIS-2000 Forward Radio Configurations

• Radio Configuration 1 - Required• Backwards compatible mode with TIA/EIA-95-B• Based on 9,600 bps Traffic

• Radio Configuration 2• Backwards compatible mode with TIA/EIA-95-B• Based on 14,400 bps Traffic

• Radio Configurations 3, 4, and 5• All use new IS-2000 coding for improved capacity• RC3 is based on 9,600 bps and goes up to 153,600 bps• RC4 is based on 9,600 bps and goes up to 307,200 bps• RC5 is based on 14,400 bps and goes up to 230,400 bps


Data Rates & Radio ConfigurationsData Rates & Radio ConfigurationsRadio

Configuration

RC1

RC2

RC3

RC4

RC5

RC6

RC7

RC8

RC9

SpreadingRate

SR11 carrier1.2288MCPS

SR33.6864MCPS

as3 carriers

1.2288MCPS

Forward Link

Required. IS-95B CompatibleNo cdma2000 coding features

Compatible with IS-95B RS2No cdma2000 coding features

Quarter-rate convolutional or Turbo Coding, base rate 9600

Half-rate convolutional or Turbo Coding, base rate 9600

3/8 rate convolutional or Turbo Coding, base rate 14400

1/6 rate convolutional or Turbo coding, base rate 9600

Required. 1/3 rate convolutional or Turbo coding, base rate 9600

¼ or 1/3 rate convolutional orTurbo coding, base rate 14400

½ or 1/3 rate convolutional or Turbo encoder, base rate 14400

9600variable

14400variable

9600153600

9600307200

14400230400

9600307200

9600614400

14400460800

144001036800

Reverse Link

¼ rate conv or Turbo coding, 9600½ rate conv or Turbo coding, 9600

¼ rate convolutional or Turbo Coding, base rate 14400

Required. ¼ or 1/3 convolutionalOr Turbo coding, base rate 9600

¼ or ½ convolutional or Turboencoding

9600153600307200

14400230400

9600307200614400

144004608001036800

Required. IS-95B CompatibleNo cdma2000 coding features

Compatible with IS-95B RS2No cdma2000 coding features

9600variable

14400variable

DataRates

DataRates

RadioConfiguration

RC1

RC2

RC3

RC4

RC5

RC6


2G Today: IS-95 CDMA Channels2G Today: IS-95 CDMA Channels

• Existing IS-95A/JStd-008 cdma offers one physical structure using just the channels shown above

• IS-2000 cdma is backward-compatible with this IS-95, but offers additional radio configurations with additional channels

FORWARD CHANNELS REVERSE CHANNELS

BTS

W0: PILOT

W32: SYNC

W1: PAGING

Wn: TRAFFIC

ACCESS

TRAFFIC


cdma2000 Channelscdma2000 Channels

• Dedicated: Point-to-point, single BS → single MS• Common: Shared information for/from multiple MS

PilotSyncPagingControlAuxiliary pilotQuick pagingBroadcast

Common

Auxiliary pilotControlFundamentalSupplemental

Dedicated

AccessControl

PilotControl

FundamentalSupplemental

Common

Dedicated


cdma2000 SR1 CDMA Channelscdma2000 SR1 CDMA Channels

Dedicated Control Channel

Same coding as IS-95B,Backward compatible



Broadcast Channel

Quick Paging Channel

Common Power Control Channel

Common Assignment Channel

Common Control Channels

Forward Traffic Channels

Fundamental Channel

Supplemental CodeChannels IS-95B only

SupplementalChannels RC3,4,5

Includes PowerControl Subchannel

Enhanced Access Channel

CommonControl Channel

DedicatedControl Channel

Reverse FundamentalChannel (IS95B comp.)

Reverse Supplemental Channel

Access Channel(IS-95B compatible)

BTS

FORWARD CHANNELS

F-Pilot

F-Sync

PAGING

F-BCH

F-QPCH

F-CPCCH

F-CACH

F-CCCH

F-DCCH

1

1

1 to 7

0 or 1

0 or 1

0 or 1

0 or 1

0 to n

0 or 1

F-FCH

F-SCCH

F-SCH

0 to many

0 or 1

0 to 7

0 to 2

IS-95B only

R-TRAFFIC

REVERSE CHANNELS

R-Pilot

R-CCCH

R-DCCH

R-FCH

R-SCH

R-EACH

1

1

0 or 1

0 or 1

0 to 2

R-ACH or

0 or 1

cdma2000 Rev A

IS-95 or cdma2000 Rev 0 or Rev A

cdma2000 Rev 0 or Rev A

cdma2000 Rev 0 or Rev A (related to traffic)

IS-95B only

F-TRAFFIC

IS-95 or cdma2000 Rev 0 or Rev A (related to traffic)

IS-95 or cdma2000 Rev 0


ContentsContents



Existing CDMA Voice NetworksExisting CDMA Voice Networks

• The cdma voice conversation’s 20-ms frames are carried as packets between mobile and the Selector• The selector assembles frames being sent to the mobile and

disassembles frames coming from the mobile

• Frame contents normally include voice and occasional signaling; may also include data if additional equipment is included (not shown)

• The vocoders in the BSC and the mobile convert the packet stream into continuous DS-0 audio for the end-users• The MSC makes a circuit-switched connection for call


Existing CDMA Voice Networks (cont.)Existing CDMA Voice Networks (cont.)

t1t1CIRCUIT-SWITCHED VOICE TRAFFIC

v CESEL

rf

t1Handset

BTS

(C)BSC orAccess Manager

Switch

PSTN

POINT-TO-POINT PACKETS

14400 bps max

2nd Generation cdma Networks were designed primarily to handle voice


Data Capability Today on a CDMA NetworkData Capability Today on a CDMA Network

• Data to/from the user connects near the selector in the BSC• Passed through the switch as 56kb/s data links in 64kb/s DS-0s

• Data connection to outside world handled by IWF InterWorking Function• Includes modems to convert data stream into DS-0 for dial-up

uses

• Can contain data routers to access IP or PPP networks

• May include capability for FAX and other communications modes


Data Capability Today on a CDMA Network (cont.)Data Capability Today on a CDMA Network (cont.)

t1t1 v CESEL

t1

GatewayServer

InternetVPNs

PSTN

IWFrf

CIRCUIT-SWITCHED VOICE TRAFFIC

BTS

(C)BSC orAccess Manager

Switch

BackboneNetwork

HandsetPOINT-TO-POINT PACKETS

PROPRIETARY SLOW IP TRAFFIC

DIAL-UP ACCESS14400 bps max

Additional hardware was needed to carry data on a 2G network


cdma2000 Networkcdma2000 NetworkPacket Data Requires New H/W including PCF and PDSN

HLRHome Access

Provider Network

VLR

Visited Access ProviderNetwork

MobileClient

L

Radio Network

R-P

PDSN

PCF

Internet

VisitedAAA

HomeAAA

Home Access ProviderIP Private Network

Home Network

MSC

BSC AAA - Authentication, Authorization, and Accounting PCF - Packet Control FunctionPDSN - Packet Data Service NodeHA – Home AgentRN – Radio Network


3G Data Capabilities: 1xRTT CDMA Network3G Data Capabilities: 1xRTT CDMA Network

• This requires a Packet Data Serving Node• ISP and operator-provided services are provided by external

Home Network and Home Agent servers

• Authentication, Authorization, and Accounting provided by external server

• The IWF (InterWorking Function) is still maintained to allow old mobiles to use dial-up and WAP/wireless web keypad access


3G Data Capabilities: 1xRTT CDMA Network (cont.)3G Data Capabilities: 1xRTT CDMA Network (cont.)

t1t1 v CESEL

rf

t1

R-P Interface

fiber - ATM PDSNForeign Agent

PDSNHome Agent

BackboneNetworkInternet

VPNs

PSTN

T TSECURE TUNNELSAuthenticationAuthorizationAccountingAAA

CIRCUIT-SWITCHED VOICE TRAFFIC

BTS(C)BSC/Access Manager

Switch

WirelessMobile Device

POINT-TO-POINT PACKETS

FAST IP PACKET TRAFFIC

Fast!

For full-featured data access over a 3G network, a true IP connection must be established to outside Packet Data Networks


ConclusionsConclusions• IS-2000 is Backwards Compatible with

TIA/EIA-95-B

• Provides 2x Capacity Improvement Over TIA/EIA-95-B

• Improved Coding

• Improved Modulation

• Coherent Reverse Link Demodulation (Mobile Pilot)

• Fast Forward Link Power Control

• Supports High Speed Data for New Applications


AcknowledgementsAcknowledgements

• Selected Materials Were Contributed By:• Agilent Technologies Wireless Network Services

Division, Wireless Institute of Technology Group, Melbourne, FL

• Scott Baxter and Associates, Nashville, TN• 3GPP2 web site: www.3gpp2.org

An Overview of cdma2000 Technology Concepts · 2004-07-21 · An Overview of cdma2000 Technology...

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