2G and 3G Air Interfaces

Air Interfaces Outline

Definitions– Frequency Division Duplex

(FDD)– Time Division Duplex (TDD)– Frequency Division Multiple

Access (FDMA)– Time Division Multiple Access

(TDMA)– Code Division Multiple Access

(CDMA) Second Generation Radio

Systems– US TDMA– CDMA– GSM

Third Generation Terrestrial Radio Systems– UWC-136– UTRA– cdma2000– TD-CDMA– DECT– Other 3G WCDMA Systems

CDMA I CDMA II W-CDMA/Japan WCDMA/NA WIMS W-CDMA

Some 3G Satellite Radio Systems– SW-CDMA & SW-CTDMA– ICO Satellite RTT– Horizons System RTT

Frequency Division Duplex (FDD)

In FDD Information From the Handset to the Base Station Is Carried on One Frequency and Information From the Base Station to the Handset Is Carried on Another

Forward Link FrequencyReverse Link Frequency

Time Division Duplex (TDD)

In TDD Information From the Handset to the Base Station Is Transmitted at One Time on One Frequency and Information From the Base Station to the Handset Is Transmitted at Another Time on the Same Frequency

Forward LinkTime Slot

Reverse LinkTime Slot

Advantages and Disadvantages of TDD

Advantages of TDD Over FDD– More Efficient for Asymmetric Data– Reverse Link and Forward Link Propagation Conditions Are

Identical Forward Link Beamforming Can Be Base on Reverse Link

– Less Complex RF Transceiver Disadvantages of TDD Over FDD

– More Delay– Limited Communications Distance

Frequency Division Multiple Access (FDMA)

Each User Occupies a Different Frequency Channel

Frequency

Tim

e

Cha

nnel

1

Cha

nnel

2

Cha

nnel

3

Cha

nnel

4

Cha

nnel

5

Cha

nnel

N

Time Division Multiple Access (TDMA)

Each User Occupies a Time Slot TDMA Is Really FDMA With Each Frequency Channel

Divided Into Time Slots

Tim

e

TS

2T

S3

TS

1

TS

2T

S3

TS

1

TS

2T

S3

TS

1

TS

2T

S3

TS

1

TS

2T

S3

TS

1

TS

2T

S3

TS

1Frequency

Code Division Multiple Access (CDMA)

Each User Has a Unique Code CDMA Is Really FDMA With Multiple Users, Identified by

Codes, Sharing Each Frequency Channel

User 1User 2User 3

User N

User 1User 2User 3

User N

Tim

e

Frequency

US TDMA

US TDMA Highlights

TDMA Time Division Multiple Access Improved Capacity Over AMPS Backward Compatible With AMPS Incremental Migration From AMPS to D-AMPS Use of Same Frequency Band by AMPS and D-AMPS Acceptable Voice Quality Support of New Services Support of Dual Mode (AMPS/TDMA) Phones Improved Voice Privacy Improved Fraud Control (Use of Authentication) US TDMA Carriers

– AT&T Wireless (800 and 1800MHz)– Southwestern Bell Mobile Systems (800 and 1800MHz)– Cellcom of Israel (800MHz)– Etc.

Control Channels in D-AMPS

IS-54b:Analog control channelsShared with amps

IS-136:Analog Control Channels: AmpsDigital Control Channels: D-amps

J-STD-009,010,011:Analog Control ChannelsShared With Amps (1800MHz)

AMPS 800MHzD-AMPS 800/1800MHz

US TDMA Waveform

3 Users Per Frequency Channel

/4-DQPSK Modulation

TS1 TS2 TS3 TS4 TS5 TS630kHz

40ms

I

Q

/4-DQPSK

US TDMA Specifications

Multiple Access TDMADuplex Scheme FDDChip Rate Not ApplicableFrame Length 40msBandwidth 30kHzData Modulation /4 - DQPSKSpreading Modulation Not ApplicableChannel Coding ConvolutionalPower Control NoneDiversity BS Antenna Selection Diversity

US TDMA Interesting Features

IS-136 Versus IS-54– Digital Control Channels Added for TDMA

New Set of Frequencies Indicator Field Added to Inform MS of Location of Control Channels

– Coded Digital Verification Color Code (CDVCC) Added to Control Channels

Frequency Reuse Same As AMPS

F2

F3F7

F1

F4F6

F5

7/21 Reuse pattern

GSM

GSM Highlights

GSM Global System for Mobile Communications Design Goals for GSM

– One Standard for Europe - Roaming Among Countries– Open Interfaces - Almost All– Digital With Frequency Reuse of 4– Rich Feature Set Similar to ISDN– Authentication and Voice Privacy– Smart or SIM Cards

Air Interface Specifications– GSM– DCS-1800– ANSI J-STD-007 or PCS 1900 Air Interface Specification for 1.8 to

2.0GHz Frequency Hopping Time Division Multiple Access (TDMA) for Personal Communication System

GSM Physical Channel

TS0 TS1 TS2 TS3 TS4 TS5200kHz

4.615ms

TS6

Absolute Frequency Channel Number (AFCN)

TS7

GSM Specifications

Multiple Access TDMADuplex Scheme FDDChip Rate Not ApplicableFrame Length 4.615msBandwidth 200kHzData Modulation GMSKSpreading Modulation Not ApplicableChannel Coding ConvolutionalPower Control Fwd: minimum 60ms

Rvr: once per secondDiversity BS Antenna Selection Diversity

GSM Logical Channels

TCH(FS, HS, F9.6, F4.8, F2.4, H4.8, H2.4)

BCH(BCCH, FCCH, SCH)

CCCH(PCH, AGCH, RACH)

DCCH(SDCCH, SACCH, FACCH)

cdmaOne

cdmaOne Highlights

cdmaOne Code Division Multiple Access Based on IS-95 Air Interface Standard

Air Interface Standards– IS-95 800MHz Standard– J-STD-008 1900MHz Standard

All Base Stations Transmit on the Same Frequency All Mobile Stations Transmit on the Same Frequency Soft Handoff: Multiple Base Stations (or Sectors) Send the

Same Signal to a Single Mobile Station Handsets Have Special Receivers Called Rake Receivers That

Combine Multipath or Multiple Copies of the Same Signal Approximately 6x Improvement Per Channel Over AMPS

Capacity

cdmaOne Channels

PilotSync

PagingAccess

Traffic

1.25MHz

cdmaOne Specifications

Multiple Access CDMADuplex Scheme FDDChip Rate 1.2288McpsFrame Length 20msBandwidth 1.25MHzData Modulation BPSKSpreading Modulation Fwd: QPSK, Rvr: OQPSKChannel Coding ConvolutionalPower Control Fwd

Rvr: Open loop and closed loop. Closed loop at 800Hz

Diversity BS Antenna Selection Diversity Rake receiver

cdmaOne Soft Handoff

Example: – Three Base Stations Sending

the Same Information to the Mobile Station

– Three Base Stations Receiving the Same Information From the Mobile Station

UWC-136

What is UWC-136?

Evolution of Today’s TDMA (IS-136) Universal Wireless Communications (UWC) - 136

UWC-136

IS-136 136+ 136 HS

IS-136 and IS-136+ Highlights

136 TDMA Characteristics– Based on TIA/EIA IS-136– FDD– 30kHz Bandwidth Per Traffic Channel– Maximum Data Rate: 9.6kbps Using One Timeslot– Supports Several Methods of Handoff– Supports IS-641A ACELP Vocoder– Minimum Required Bandwidth for 7/21 Reuse Is 630kHz by 2

136+ TDMA Characteristics– Simultaneous Voice and Data – 30kHz Bandwidth Per Traffic Channel– Supports IS-641 and US1 Vocoder– Maximum User Data Rate: 14.4kbpsusing One Timeslot– Minimum Required Bandwidth for 7/21 Reuse Is 630kHz by 2– Supports Discontinuous Transmission (DTX)– Minimum Required Bandwidth for 7/21 Reuse Is 630kHz by 2

136 HS Highlights

Supports Mulitband Operation From 500MHz to 2.5GHz Can Be Deployed in a Minimum of 1MHz of Spectrum Coexist With Existing Second Generation Systems FDD for 136 HS Outdoor and FDD or TDD for 136 HS Indoor 136 HS Services Supported by 136 and 136+ Control Channels Slow Frequency Hopping Option Minimum Data Rate Requirements

– Macrocellular Pedestrian (3km/hr): 384kbps Low Speed Vehicle (100km/hr): 384kbps High Speed Vehicle (100-500km/hr): 144kbps

– Micrcellular/indoor

Pedestrian (3km/hr): 2048kbps UWC-136 Bandwidth Requirements

– 136 HS Outdoor 200kHz– 136 HS Indoor 1600kHz

UWC-136 Specifications

UWC-136+ UWC-136HS UWC-136HS Outdoors Indoor

Multiple Access TDMA TDMA TDMADuplex Scheme FDD FDD TDDChip Rate Not Applicable Note Applicable Not ApplicableFrame Length 40ms 4.615ms 4.615msBandwidth 30kHz 200kHz 1600kHzData Modulation /4 DQPSK 8PSK Q-O-QAM

/4 QPSK GMSK B-O-QAM8PSK

Time Slots 6 8 64/16Spreading Modulation Not Applicable Not Applicable Not ApplicableChannel Coding Convolutional Convolutional, Turbo Convolutional, TurboPower Control None Fwd&Rvr Fwd&Rvr

Time slot Time slotDiversity Antenna Antenna Antenna

Smart Antenna Smart Antenna

136 HS Frequency Planning

Coexistence of 136 HS and 136

Potential Cell Plan

E1 E2 E3

D7...D1 D2 D3 D4 D5 D6

200kHz 30kHzGuardband

D13

D2

D16

D12

D7

D21

D9

D1

D15

D14

D4

D18

D8

D3

D17

D19

D11

D6

D20

D10

D5

Base Station

UWC-136HS Forward an Reverse Link Features

136 HS Outdoor– Forward and Reverse Link Power Control on a Time Slot Basis Via

Signaling Messages– Antenna Diversity With Two Receiver Chains and Antennas– 8-PSK and GMSK Modulation

136 HS Indoor– Forward and Reverse Link Power Control on a Time Slot Basis Via

Signaling Messages– Multiple Antennas or Adaptive Antennas– B-O-QAM and Q-O-QAM Modulation

Enhancements– Inter-cell Interference Suppression Via Adaptive Array Antennas and

Joint Demodulation of Co-channel Signals– Fast Power Control on Frame by Frame Basis– Improved Channel Coding Using Optimized Puncturing, Turbo

Codes, Etc.

UWC-136 Modulation Schemes

I

Q

I

Q

136 136+

I

Q

/4-DQPSK

/4 -QPSK

8-ary PSK

GMSKI

Q

B-O-QAM

Q

I Q-O-QAM

I

Q

I

Q

/4-DQPSK

/4 -QPSK

136HS Outdoors 136HS Indoors

I

Q

8-ary PSK

I

Q

UTRA

UTRA Highlights

UTRA UMTS Terrestrial Radio Access ETSI SMG2 Proposal to ITU In the Paired Band (FDD - Frequency Division Duplex) of

UMTS the System Adopts the Radio Access Technique Formerly Proposed by the W-CDMA Group

In the Unpaired Band (TDD - Time Division Duplex) the UMTS System Adopts the Radio Access Technique Proposed Formerly by the TD-CDMA Group

Variable Spreading Factor (VSF) and Multicodes Used for Variable Data Rates

Handoff to GSM

UTRA Multiple Data Rate Support

Variable Spreading Factor (VSF) in a Code for Multi-rate Data Services Multicode Scheme for Higher Data Rate

Rchip

Rsymbol Max/2j

SpreadingFactor

Variable Spreading Factor

Code 0

Code 1

Code 2

Code N

PN CodeR/M

R/M

R/M

Pilot

TrafficR bps

SFmin = 8(RL) = 16 (FL)

Multi-code

UTRA Inter-Frequency Handoff The Downlink Is Slotted So That a Single Mobile Receiver Can Make Measurements on Other Frequencies When a Frame Is Slotted, It Is Transmitted at a Higher Power to Maintain a Constant Quality (BER or FER) When the Processing Gain Is Lowered.

When Sending High Data Rate Services Where Changing the Processing Gain Is Not Possible, Some Frames Are Compressed With a Lower Processing Gain for That Frame.

TfIdle period available for

interfrequency measurements

Compressed transmission duringone interleaver span

UTRA FDD Specifications

Multiple Access DS-CDMADuplex Scheme FDDChip Rate 4.096/8.192/16.384McpsFrame Length 10msBandwidth 5/10/20MHzData Modulation Fwd Link: QPSK Rvr Link: QPSKSpreading Modulation Fwd Link: BPSK

Rvr Link: QPSKChannel Coding Convolutional, Outer RS CodingPower Control Closed, open, and outer loop

at 1600/secDiversity Rake, antenna diversity

UTRA TDD Specifications

Multiple Access T/CDMADuplex Scheme TDDChip Rate 4.096McpsFrame Length 10msBandwidth 5MHzData Modulation QPSKSpreading Modulation QPSKChannel Coding Convolutional, Outer RS CodingPower Control Closed, open, and outer loop

at 100-800/secDiversity Rake, antenna diversity

UTRA Key Features

FDD Mode Requires No Inter-BS Synchronization TDD Mode Requires Inter-BS Synchronization Forward and Reverse Link Pilots

cdma2000

cdma2000 Highlights

Direct Sequence and Multi-carrier Waveform Options on Forward Link

Direct Sequence and Multi-carrier Waveforms May Employ Spatial Diversity

Forward and Reverse Link Fast Power Control Auxiliary Pilots Provided for Antenna Array Applications 5 and 20 Millisecond Frame Lengths Utilize Turbocodes Coherent Reverse Link Using a Reverse Link Pilot Forward Link Fast Power Control Reverse Link Continuous Transmission

– cdmaOne Discontinuous Transmission Base Stations Are Synchronized Via GPS

cdma2000 Services Voice

– V1– V2

Packet– P1– P2

– P3 Circuit

– C1– C2– C3

Voice and Packet– VP1– VP2

Voice and Circuit– VC1– VC2

Packet and Circuit– PC1– PC2– PC3

Voice, Packet and Circuit– VPC1– VPC2

0

500

1000

1500

2000

2500

13

69

121

36

912

RS1

RS2

Dat

a R

ate

(kbp

s)

cdma2000 Frequency Plan

Two options for using Bandwidth– Multi-Carrier (Forward Link Only)– Direct Sequence

1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz

1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz 1.25MHz

Multi-Carrier

Direct Sequence

625kHz Guardband

cdma2000 Specifications

Multiple Access FDD: DS-CDMA TDD: T/CDMADuplex Scheme FDD/TDDChip Rate 1.2288Mcps x N N=1,3,6,9,12Frame Length 20/5msBandwidth 2.5/5/10/15/20MHzData Modulation Fwd Link: QPSK Rvr Link: BPSKSpreading Modulation Fwd Link: QPSK

Rvr Link: QPSKChannel Coding Convolutional, TurboPower Control Closed, open, and outer loop

at 800/sec FDD and 800/sec TDD

cdma2000 Channel Structure

Two Types of Physical Channels:– Dedicated Physical Channel (DPHCH)– Common Physical Channel (CPHCH)

DPHCH CPHCH

F-DAPICH/R-PICH F/R-SCHT F/R-DCCH F/R-FCH

F/R-SCH1 F/R-SCH2

F-PICH F-CAPICH F/R-CCHT

F-PCH F-SYNC F/R-CCCH R-ACH

Shared cdma2000

cdma2000 - Two Phases

cdma2000 Phase 1– 1.25MHz Channel With Enhanced Coding and Signal

Processing (N = 1)– Physical Layer Capacity Improvements With Minimal

Modifications to cdma2000 Base Stations– Higher Data Rates Via Improvements in Physical Layer– Data Capacity Improvements Via Enhanced Medium Access

Control (MAC) Layer Quality of Service (QoS) Capabilities cdma2000 Phase II

– Full IMT-2000 Compliance– Full Packet and Circuit Data Capability up to 2Mbps– Full MAC Layer QoS Capabilities

TD-SCDMA

TD-SCDMA Highlights

TD-SCDMA Time Division - Synchronous Code Division Multiple Access

China CWTS Proposal to ITU Deployment Areas Will Be Medium and Large Cities Compatibility With 2G, Especially GSM in China High User Density Cell Sizes < 2km Environment:

– Indoor– Outdoor to Indoor– Pedestrian

TD-SCDMA Variable Data Rate

Basic Rate (9.6kbps), to Provide Higher Data Rate:– Aggregate Multiple Time Slots– Aggregate Multiple Code Channels– Use an Adaptive TDD Scheme (for Asymmetric

Data)– Use a Higher Order Modulation Scheme (16QAM) – Use Multiple Frequency Carriers

To Provide Low Speed Data (for Example, 4.8kbps) Service, a Simple Bit Repeating Scheme Can Be Used

What is SCDMA?

Synchronous Code Division Multiple Access (SCDMA)

Definition– Signals From the Mobiles Will

Be Synchronous at the BS

Advantages– All CDMA Code Channels Will

Be Orthogonal Reducing Co-channel Interference

– Higher Capacity – Simplified Hardware and Lower

Cost

BaseStation

Code Channel 1

Code Channel 2

Code Channel 3

Code Channel N

TD-SCDMA Specifications

Multiple Access TDMA/CDMADuplex Scheme TDDChip Rate 1.136McpsFrame Length 5msBandwidth 1.4MHzData Modulation DQPSK/16QAMSpreading Modulation BPSKChannel Coding ConvolutionalPower Control Reverse link: open and closed 200/sDiversity 8 element smart array

TD-SCDMA Time Slot Structure

Total 8 Time Slots (TSs) With 16 Channels Per TS

Walsh Codes Separate Users Within a TS

TSd0 TS

d1 TSd2 TS

d3 TSd4 TS

u0 TSu1

TSu0 TS

u1

1.4MHz

5ms

Guard band

DECT

DECT Highlights

DECT Digital Enhanced Cordless Telecommunications ETSI Proposal to ITU Data Transmission Rates up to 2.88Mbps Wireless Relay Stations Coexistence of Uncoordinated Installations on the Same Frequency

Bands Access to Different Systems by the Same Handset

– GSM– ISDN– Data Networks

DECT Authentication Module (DAM)– 128 Bit User Authentication Key– Cipher Generated During Authentication– 64 Bit Cipher Key

DECT Specifications

Multiple Access MC/TDMADuplex Scheme TDDChannel Rate 1.152, 2.304, 3.456MbpsFrame Length 10msBandwidth 1728MHzData Modulation /2-D2PSK, /8-DQPSK

/8-D8PSK, GFSKChannel Coding Reed-SolomonDiversity Space diversity

Multi-Carrier TDMA Multi-Carrier Time Division Multiple Access

Tim

eslo

ts

Frequencies

BaseStation

BaseStation

DECT

Symmetric Connection Asymmetric Connection

1.728MHz

0-5ms

5-10ms

Tx TxTx

RxTx

Tx

0-5ms

5-10ms

Tx Tx

Rx Rx

DECT Seamless Hand-off

0

12

0

12

11

23

BaseStation

BaseStation

11

23

f1

f4

Other 3G WCDMA Systems - Page One CDMA I Code Division Multiple Access I

– South Korea TTA Proposal to ITU– Transmission Limitation for Inter-frequency Handoff

Limit the Data Transmission on the Forward Link to Find Other Frequencies Without Sacrificing Link Performance

– Synchronous Reverse Link Reverse Link Synchronization Using Time Alignment Command

– Synchronous CDMA System Synchronous Cells Optional Asynchronous Mode Under Progress

CDMA II Code Division Multiple Access II– South Korea TTA Proposal to ITU– Asynchronous Inter-BS Operation

W-CDMA/NA Wideband Code Division Multiple Access / North America– USA T1P1 Contribution to ITU– FDD: No Inter-BS Synchronization TDD: Inter-base Station Synchronization

Other 3G WCDMA Systems - Page Two W-CDMA/Japan Wideband Code Division Multiple Access /

Japan– Japan Association of Radio Industries and Businesses (ARIB)

Proposal to ITU– FDD and TDD Modes

FDD Does Not Require Accurate Inter-base Station Synchronization TDD Requires Accurate Inter-base Station Synchronization

– Forward and Reverse Link Pilots Forward Link Pilot is a Separate Code for FDD Mode Reverse Link Pilot is I/Q Multiplexed for FDD Mode Forward and Reverse Link Pilots are Time Multiplexed for TDD Mode

WIMS-WCDMA Wireless Multimedia and Messaging Services (WIMS) W-CDMA– No Inter-BS Synchronization Required

Other 3G WCDMA Air Interface Specifications-One

CDMA I CDMA II W-CDMA/JapanMultiple Access DS-CDMA DS-CDMA FDD:DS-CDMA

TDD:T/CDMADuplex Scheme FDD FDD FDD/TDDChip Rate 0.9216/3.6864.14.7456Mcps 1.024/4.096/8.192/16.384Mcps 1.024/4.096/8.192/16.384McpsFrame Length 10ms 10ms 10msBandwidth 1.25/5/10/20MHz 1.25/5/10/20MHz FDD: 1.25/5/10/20MHzData Modulation Fwd Link: QPSK Fwd Link: QPSK Fwd Link: QPSK

Rvr Link: BPSK Rvr Link: BPSK Rvr Link: FDD: Dual channel QPSK TDD: QPSKSpreading Modulation Fwd Link: QPSK Fwd Link: QPSK Fwd Link: QPSK

Rvr Link: OCQPSK Rvr Link: OCQPSK/CQPSK Rvr Link: QPSKChannel Coding Convolutional, outer Reed-Solomon Convolutional, Turbocodes Convolutional, Turbo codingPower Control Fwd link: closed 1600/sec Fwd link: closed 1600/sec and outerFDD: Closed, open, and outer loop at 1600/sec

Rvr link: open and closed 1600/s Rvr link: open and closed 1600/s TDD: Closed at 800/secDiversity Rake, antenna diversity, Rake, antenna diversity, Rake, BS antenna diversity

time switched Tx on Fwd Link time switched Tx on Fwd Link optional MS antenna diversity

Other 3G WCDMA Air Interface Specifications-Two

WCDMA/NA WIMS-WCDMAMultiple Access FDD:DS-CDMA FDD: DS-CDMA

TDD:T/CDMA TDD: Fwd:DS W-CDMA Rvr: DS S-TDMADuplex Scheme FDD/TDD FDD/TDDChip Rate 4.096/8.192/16.384Mcps 4.096/8.192/16.384McpsFrame Length 10ms 10msBandwidth 5/10/20MHz 5/10/20MHzData Modulation Fwd Link: QPSK Fwd Link: QPSK

Rvr Link: FDD: Dual channel QPSK TDD: QPSKRvr Link: QPSKSpreading Modulation Fwd Link: FDD:BPSK TDD:QPSK Fwd Link: QPSK

Rvr Link: QPSK Rvr Link: QPSKChannel Coding Convolutional, outer Reed-Solomon ConvolutionalPower Control FDD: Closed, open, and outer loop Adaptive power control

FDD: 1600/sec TDD:100-800/sec 1600/secDiversity Rake, BS antenna diversity Rake, BS antenna diversity

optional MS antenna diversity

Satellites: SW-CDMA & SW-CTDMA

Satellites: SW-CDMA & SW-CTDMA

Why WCDMA for Satellites?– Full Frequency Reuse Easing Resource Allocation– Softer Handoff– Suitable for Interference Mitigation (MUD)

Two European Radio Transceiver Technologies (RTT) Proposals:– SW-CDMA

For Global Systems (Low Earth Orbit (LEO)/medium Earth Orbit(MEO)) Adaptation of the Terrestrial ETSI UTRA/ARIB W-CDMA Proposals to the Satellite

Environment

– SW-CTDMA For Regional Systems (HEO/GEO) Hybrid Solution Found Particularly Attractive for Regional Systems (HEO/GEO Orbits) Some Commonality With ETSI UTRA Combines CDMA and TDMA Advantages

SW-CDMA & SW-CTDMA Specifications

SW-CDMA SW-TCDMAMultiple Access DS-CDMA Rvr: W-O-C/TDM

Fwd: W-QS-C/TDMADuplex Scheme FDD FDD or F/TDDChip Rate 4.096Mcps (2.048Mcps option) 4.096Mcps (2.048Mcps option)Frame Length 10ms (20ms option) 20msBandwidth 5MHz (2.5MHz as option) 5MHz (2.5MHz as option)Data Modulation Fwd: QPSK (BPSK low data rate) QPSK or Dual BPSK

Rvr: Dual BPSKHigh Power Paging Yes YesChannel Coding Convolutional, outer Reed-Solomon Convolutional, outer Reed-SolomonPower Control Open loop for RACH, Open loop for RACH,

Closed loop based on SINR+FEC Closed loop based on SINR+FEC100-400Hz update rate 100-400Hz update rate

Satellites: ICO Satellite RTT

Satellites: ICO Satellite RTT

ICO RTT:– Ten Satellites– Two Inclined Planes– Medium-earth Orbit (MEO)– Transparent Transponders

Parameters:– Access Scheme: FDMA/TDMA– Channel Spacing: 25 kHz– 6 Slots Per Channel– RF Channel Rate 18/36 kbps (Depending on Channel Type)– Convolutional Coding

1/3 Rate (for Voice) 1/2 Rate (for Data)

Satellites: Horizons System RTT

Satellites: Horizons System RTT

System Parameters:– TDMA/FDM Multiple Access Scheme

200 kHz Channels, Reservation Based Slot Allocation

– Bandwidth Efficient Modulation and Coding 16-QAM, Turbo Coding

– Bandwidth on Demand Capability ATM-like Cell-switching Protocol

Use of Standard PC Communication Applications– Compatible With Industry Standard Modem Interfaces

Service Compatibility, Roaming With Terrestrial IMT-2000

High Power GEO Mobile Satellites for 2002 Service

Laptop (144kbps)