2G and 3G Air Interfaces

1
2G and 3G Air Interfaces
2
Air Interfaces Outline

• 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

• 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

3
Frequency Division Duplex (FDD)
Forward Link Frequency
Reverse Link Frequency

• 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

4
Time Division Duplex (TDD)
Reverse Link Time Slot
Forward Link Time Slot

• 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

5
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

6
Frequency Division Multiple Access (FDMA)

• Each User Occupies a Different Frequency Channel

Time
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel N
Frequency
7
Time Division Multiple Access (TDMA)

• Each User Occupies a Time Slot
• TDMA Is Really FDMA With Each Frequency Channel
  Divided Into Time Slots

TS3
TS3
TS3
TS3
TS3
TS3
Time
TS2
TS2
TS2
TS2
TS2
TS2
TS1
TS1
TS1
TS1
TS1
TS1
Frequency
8
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 1 User 2 User 3 User N
User 1 User 2 User 3 User N
Time
Frequency
9
US TDMA
10
US TDMA Highlights

• TDMA º 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
• ATT Wireless (800 and 1800MHz)
• Southwestern Bell Mobile Systems (800 and
  1800MHz)
• Cellcom of Israel (800MHz)
• Etc.

11
Control Channels in D-AMPS
AMPS 800MHz D-AMPS 800/1800MHz
IS-54b Analog control channels Shared with amps
IS-136 Analog Control Channels Amps Digital
Control Channels D-amps
J-STD-009,010,011 Analog Control Channels Shared
With Amps (1800MHz)
12
US TDMA Waveform
40ms
30kHz

• 3 Users Per Frequency Channel
• P/4-DQPSK
• Modulation

I
?/4-DQPSK
Q
13
US TDMA Specifications
14
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

7/21 Reuse pattern
15
GSM
16
GSM Highlights

• GSM º 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

17
GSM Physical Channel
TS0
TS1
4.615ms
TS2
TS3
TS4
200kHz
TS5
TS6
TS7
Absolute Frequency Channel Number (AFCN)
18
GSM Specifications
19
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)
20
cdmaOne
21
cdmaOne Highlights

• cdmaOne º 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

22
cdmaOne Channels
Pilot
Sync
Paging
Access
Traffic
1.25MHz
23
cdmaOne Specifications
24
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

25
UWC-136
26
What is UWC-136?

• Evolution of Todays TDMA (IS-136)
• Universal Wireless Communications (UWC) - 136

UWC-136
IS-136
136
136 HS
27
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 ??14.4kbps?using 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

28
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) gt?384kbps
• Low Speed Vehicle (?100km/hr) gt?384kbps
• High Speed Vehicle (100-500km/hr) gt?144kbps
• Micrcellular/indoor
• Pedestrian (?3km/hr) gt?2048kbps
• UWC-136 Bandwidth Requirements
• 136 HS Outdoor 200kHz
• 136 HS Indoor 1600kHz

29
UWC-136 Specifications
30
136 HS Frequency Planning

• Coexistence of 136 HS and 136
• Potential Cell Plan

Guardband
200kHz
30kHz
E1
E2
E3
D7...
D1
D2
D3
D4
D5
D6
31
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.

32
UWC-136 Modulation Schemes
136HS Outdoors
136
136
136HS Indoors
?/4-DQPSK
?/4-DQPSK
8-ary PSK
I
I
?/4 -QPSK
GMSK
?/4 -QPSK
B-O-QAM
Q
Q
8-ary PSK
33
UTRA
34
UTRA Highlights

• UTRA º 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

35
UTRA Multiple Data Rate Support

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

Pilot
Code 0
Rchip
R/M
PN Code
Spreading Factor
SFmin 8(RL) 16 (FL)
Code 1
Traffic R bps
Rsymbol Max/2j
R/M
Code 2
Variable Spreading Factor
R/M
Code N
Multi-code
36
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.

37
UTRA FDD Specifications
38
UTRA TDD Specifications
39
UTRA Key Features

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

40
cdma2000
41
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

42
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

43
cdma2000 Frequency Plan

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

625kHz Guardband
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
Multi-Carrier
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
1.25MHz
Direct Sequence
44
cdma2000 Specifications
45
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-PICH F-CAPICH F/R-CCHT
F/R-SCH1 F/R-SCH2
F-PCH F-SYNC F/R-CCCH R-ACH
Shared cdma2000
46
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

47
TD-SCDMA
48
TD-SCDMA Highlights

• TD-SCDMA º 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 lt 2km
• Environment
• Indoor
• Outdoor to Indoor
• Pedestrian

49
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

50
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

Base Station
51
TD-SCDMA Specifications
52
TD-SCDMA Time Slot Structure
5ms
1.4MHz
Guard band

• Total 8 Time Slots (TSs) With 16 Channels Per TS
• Walsh Codes Separate Users Within a TS

53
DECT
54
DECT Highlights

• DECT º 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

55
DECT Specifications
56
Multi-Carrier TDMA

• Multi-Carrier Time Division Multiple Access

Base Station
Timeslots
Base Station
Frequencies
57
DECT
Tx
0-5ms
Tx
5-10ms
Tx
0-5ms
Tx
Rx
Tx
Rx
5-10ms
Rx
1.728MHz
Tx
Tx

• Symmetric Connection
• Asymmetric Connection

58
DECT Seamless Hand-off
Base Station
Base Station
0
0
f1
12
12
11
11
f4
23
23
59
Other 3G WCDMA Systems - Page One

• CDMA I º 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 º Code Division Multiple Access II
• South Korea TTA Proposal to ITU
• Asynchronous Inter-BS Operation
• W-CDMA/NA º Wideband Code Division Multiple
  Access / North America
• USA T1P1 Contribution to ITU
• FDD No Inter-BS Synchronization TDD Inter-base
  Station Synchronization

60
Other 3G WCDMA Systems - Page Two

• W-CDMA/Japan º 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 º Wireless Multimedia and Messaging
  Services (WIMS) W-CDMA
• No Inter-BS Synchronization Required

61
Other 3G WCDMA Air Interface Specifications-One
62
Other 3G WCDMA Air Interface Specifications-Two
63
Satellites SW-CDMA SW-CTDMA
64
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

65
SW-CDMA SW-CTDMA Specifications
66
Satellites ICO Satellite RTT
67
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)

68
Satellites Horizons System RTT
69
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

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