Part 2: Principle and Implementation Part 2: Principle and Implementation of EVDO Systems of EVDO Systems

WLL SHORT TRAINING

UNIT 1

UNIT 2

EVDO Theory EVDO Theory Unit 1Unit 1

AT

Target AN

Source AN

PCF PDSN

AN AAA

A12 AAA

AN

IP Network

AT

IP Network

AT

Target AN

Source AN

PCF PDSN

AN AAA

A12 AAA

AN

IP Network

AT

IP Network

1X EVDO Network Structure1X EVDO Network Structure

Comparison of EVDO and 1x NetworksComparison of EVDO and 1x Networks

MS/AN

HLR

PDSN

AAA

BTSB BSCB PCF

MSC

ANAAA

Network ImplementationNetwork Implementation

Changed Parts in UpgradingChanged Parts in Upgrading

• BTS side: • - If new EVDO carrier is added

• Add EVDO base band processing part• Add related Radio transmission part, keep

antenna and feeder.

• - If upgrading 1x carrier to EVDO carrier• Add EVDO base band processing part• Keep antenna and feeder no change

Changed Parts in Upgrading (Cont.)

• BSC side: add EVDO processing part, upgrade related software• - EVDO Signaling• -Increased EVDO data capacity

UNIT 1

UNIT 2

EVDO Channel Structure & Key EVDO Channel Structure & Key TechniquesTechniques

• Forward Link Channel Structure• Reverse Link Channel Structure• Key Techniques

Forward Channel StructureForward Channel Structure

ControlMediumAccessControl

Pilot Traffic

ReverseActivity Channel

ReversePower

Control(RPC)

Forward

DRC Lock

Forward Data Time SlotForward Data Time Slot

Forward Pilot ChannelForward Pilot Channel

The Pilot channel is sent as 96 chip bursts, each of which is located at the center of each half slot.

The Pilot channel is transmitted at the full sector power.

Forward MAC ChannelForward MAC Channel

• The Reverse Power Control Channel (RPC channel) and the DRCLock Channel are time-division multiplexed.

• RPC channel is used for reverse power control.• DRCLock is used to indicate if the reverse Date Rate

Control (DRC) channel message is received or not.• Reverse Activity (RA) channel is CDMed with RPC

channel + DRCLock channel• Reverse Activity Bit (RAB) is transmitted in RA

channel, which is broadcasted by AN to inform ATs the current reverse traffic channel status.

MAC IndexMAC Index

Forward Control ChannelForward Control Channel

Forward Control ChannelForward Control Channel

• Data rate is 38.4 or 76.8kbps.• The Control Channel Cycle is of 256 slots.• Broadcast Overhead messages and Page

messages are always delivered by using Synchronous Capsule (AC).

• Asynchronous Capsule (AC) used to deliver ACK messages and RLP Control messages, may be sent at any time during which the AN is not sending a synchronous capsule.

Forward Traffic ChannelForward Traffic Channel

• Supported data rates: 38.4, 76.8, 153.6, 307.2, 614.6, 921.6, 1228.8, 1843.2, and 2457.6 Kbps.

• QPSK, 8PSK and 16-QAM are used.• Channel encoders with different code rates are

used. • Physical layer packets are of four different lengths:

1024 bits, 2048 bits, 2072 bits and 4096 bits.• A preamble is attached as the header of each

physical layer packet.• The transmitted packet = preamble + physical

layer packet

Forward Traffic Channel ParametersForward Traffic Channel ParametersData rate

(kbps)Slots per

Packet

Packet Size (bits)

Code Rate

Repetition Modulation Preamble (chips)

Effective code Rate

38.4 16 1024 1/5 9.6 QPSK 1024 1/48

76.8 8 1024 1/5 4.8 QPSK 512 1/24

153.6 4 1024 1/5 2.4 QPSK 256 1/12

307.2 2 1024 1/5 1.2 QPSK 128 1/6

307.2 4 2048 1/3 49/48 QPSK 128 16/49

614.4 1 1024 1/3 1 QPSK 64 1/3

614.4 2 2048 1/3 49/48 QPSK 64 16/49

921.6 2 3072 1/3 49/48 8PSK 64 16/49

1228.8 1 2048 1/3 0.5 QPSK 64 2/3

1228.8 2 4096 1/3 49/48 16QAM 64 16/49

1843.2 1 3072 1/3 0.5 8PSK 64 2/3

2457.6 1 4096 1/3 0.5 16QAM 64 2/3