Modul2 EVDO Operation

8/2/2019 Modul2 EVDO Operation

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Modul-2Modul-2


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Outline

EVDO Network Structure

EVDO Channel Structure

EVDO Key Technology


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BTS Operation

PILOT Channel

PAGING Channel

SYNC Channel

TRAFFIC Channel

TRAFFIC Channel

CDMA20001x Forward Channel

Maximum Power

Tx Power

1xEV-DO Forward Channel

Maximum Power

Tx Power

Co

ntrolChannel

Co

ntrolChannel

DATA


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Rev. A Improvements

Introduction to Signalling 4


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Rev. A Improvements

Introduction to Signalling 5


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1X EV-DO Network Structure

Glosary

AT : Access Terminal

PDSN : Packet Data Serving Node

AAA : Authentication, Authorization,

Acounting

Glosary

AT : Access Terminal

PDSN : Packet Data Serving Node

AAA : Authentication, Authorization,

Acounting

AN : Access Network

HA : Home Agent

PCF : Packet data Control Function

RADIUS :Remote Authentication Dial-In User

Service

AN : Access Network

HA : Home Agent

PCF : Packet data Control Function

RADIUS :Remote Authentication Dial-In User

Service


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Centralized StructureCentralized Structure

Network Implementation

Leverage Current Investment Sharing the same RF with 95/1X

Insert new EVDO channel cards and software upgrade

Flexible Network Configuration


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8Page -

EVDO Rev. A Channel

StructurePILOT

TRAFFIC

CONTROL

Reverse Activity Channel

Reverse Power Control

DRC lock

Medium Access

Control

FORWARD CHANNEL

Access

Network

(AN)

ARQ *

* Rev A Only

REVERSE CHANNEL

PILOT

Access

DATA

Traffic

PILOT

DATA

ACK

MAC

Reverse Rate Indicator

Data Rate Control

Access

Terminal

(AT)

AUX PILOT*

Data Source Control*


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Forward Channel Features

The Forward Channel (AN to AT) provides the

connections between AN and each AT.

The Forward Channel has following features:

The data rate is in a range of38.4 kbit/s~3.1 Mbps

Always at full power transmission, no power control;

Selecting the best service area according to the

measurement of C/I in Forward Channel and working

at the highest data rate;

The subscribers in a certain service area will share an

unique data service channel in a way ofTDM.


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Forward Channel Structure

Pilot: common channel for allusers to lock on the specificfrequency

Forward MAC channel :

RA : to dynamically control theworkload ofReverse Channel

RP

C : for power control of AT DRC lock : If AN cant receivethe DRC signals from AT, theDRC channel will stop the AT.

ARQ : to retransmit packeterror

Control: to send broadcasting

common configurationparameters page, signaling,channel assignment, schedule

Traffic: to send data

PILOT

TRAFFIC

CONTROL



DRC lock

Medium Access

Control

FORWARD CHANNEL

Access

Network

(AN)

ARQ *

* Rev A Only


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Basic Operation of Forward Link All sectors transmit forward

pilot bursts simultaneously Each AT estimates C/I ofactive pilots, predicts C/I andbest rate to request forforward link service

Each slot, the AT reports therequested rate and sector for

transmission via the DRCchannel

The AN schedulestransmission of preamble anddata sequentially to each AT,based on DRC contents

AT monitors preamble anddecodes data after preambleis detected

Reverse power control andother MAC information areconstantly sent over theforward channel

PILOT

TRAFFIC

CONTROL



DRC lock

Medium Access

Control

FORWARD CHANNEL

Access

Network

(AN)

ARQ

*

* Rev A Only


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FL Frame Structure

ZTE-STTELKOM Training Center Page -


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EV-DO Rev A. FL Data Rates


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Time Division Multiplexed in FL

In 1xEV-DO, the whole

forward link is used as

a shared Fat Pipe,

TDMed by all users. The subscribers share

the channel according

to the resource

allocation algorithmssuch as Round Robin

and maximizing

throughput.


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Reverse Channel Features

The reverse channels provide connections

between AT and AN.

The reverse channels have the followingfeatures:

Data rates is up to 1.8 Mbps;

Soft switch;

Dynamic power control;

Workload of reverse channels is adjusted by

rate control.


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Reverse Channel Structure Reverse Access Channels to

initiate calls or respond to AN pagingmessages at data rate of 9.6 kbps Reverse Pilot Channels

Data Channels

Auxiliary Pilot

Reverse Traffic Channels

P

ilot coherent demodulation

MAC,

DRC to give instructions to AN,including the requested data rate offorward traffic channels and theservice areas selected by forwardchannels.

RRI

to indicate the data rate of inoperation reverse data channels

DSC to give advance notice of the ATs intent to switch cells

Data to transfer reverse data

ACK to confirm data packetsdelivery from AN. NAK bits will be

sent if demodulation failed

REVERSE CHANNEL

PILOT

Access

DATA

Traffic

PILOT

DATA

ACK

MAC


Data Rate Control

Access

Terminal

(AT)

AUX PILOT*



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Basic Operation ofReverse Link

When an AT has an air link,the reverse pilot aretransmitted constantly

Reverse link is powercontrolled to achieve reliableBER

Reverse data is transmittedwhen available at ratespecified in Reverse MACprotocol

RR

IR

everseR

ate Indicator issent over the MAC channel tohelp AN decode the reversedata channel

REVERSE CHANNEL

PILOT

Access

DATA

Traffic

PILOT

DATA

ACK

MAC


Data Rate Control

Access

Terminal

(AT)

AUX PILOT*



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EV-DO Rev A. RL Data Rates

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DSC Channel Example

DSC auxiliary virtual soft handoff: The DSC notifies theAN in advance

that the target cell of this handoff to shorten the handoff delay.


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RL Access Probe Structure


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RLTraffic Channel Sub-Frame Structure


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Reverse Traffic Pilot /RRI Channel

Pilot channel : enabling

coherent demodulation at AN.

RRI channel: reporting

reverse transmission rate. Mapped from RRI 3-bit

symbol, 7-bit RRI codeword is

multiplexed with pilot before

transmission.


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Reverse Traffic ACK Channel

Indicating whether a data packet on the forward

traffic channel has been received successfully.

0 = successful

1 = failed

The ACK channel bit is transmitted at 9.6kbps

By using ACK channel in RL, AN can early

terminate multi-slot packet transmission andincreased the actual throughput.


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Reverse Traffic DRC Channel

AT sends the request of the desired data

rate and best serving sector of the forward

channel to AN over the DRC channel.

DRCCover:indicating the demanded data

rate

DRCValue: selecting the best serving

sector.


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Reverse Rate Control

The AN controls the ATs reverse link data rate

using three techniques.

Reverse Rate Limit message used by the

AN to control the transmission rate on theReverse Link for one or more ATs.

Reverse Activity Bit used to specify that the

sectors Reverse Link is busy

Reverse Rate Transition Probability Vectors

AN configures each AT with two rate transition

vectors associated with not busy or busy

statuses.


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1XEVDO Key Technology


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Adaptive Modulation and Coding

0 1000 2000 3000 4000 5000 6000 7000 80005

0

5

10

15

slot index

FLC/I(dB)

0 1000 2000 3000 4000 5000 6000 7000 80000

500

1000

1500

2000

2500

slot index

RequestedRate(kbps)

1xEV-DO dynamically adjust FL data rate, modulation

scheme and coding rate using the feedback from AT

through DRC channel


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At any instance thereAt any instance there

is only one servingis only one serving

sector for a specificsector for a specific

ATAT

AP1AP1

AP4AP4

AP2AP2

AP3AP3

AP1AP1 AP2AP2

TimeTime

Serving APServing AP

t1t1

ServingAP changeServingAP change

Serverbefore t1

Serverbefore t1

Serverafter t1

Serverafter t1

current sector forward data rate

Pilot/MAC on FWD link

Pilot/DRC/ACK/Traffic on REV Link

(APs in ATs active set)

After handoff AP2 forward data rate

Fast Cell Site Selection and Handoff


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Serving Sector Selection

-15

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

0 2 4 6 8 10 12 14

time, sec

SINR,

dB

Sector 0

Sector 1

Serving

Sector Index

Serving SectorSelection


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Ec/Io and C/I There are two main ways of expressing

signal quality in 1xEV-DO C/I is the ratio of serving sector power to

everything else C/I determines the forward data rate

mobiles measure C/I during the pilot burst

period, then from it decide what data rate to

request on the DRC

Ec/Io is the ratio of one sectors pilot

power to the total received power the mobile uses Ec/Io to choose which sectors

to request for its active set

Ec/Io and C/I are related, and one can be

calculated from the other

EVDO Ec/Io is close to 0 db near a

sector, and ranges down to -10 at a cells

edge

EVDO C/I can be above +10 db near a

sector, and -20 or lower at the edge

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Relationship of Ec/Io and C/I in 1xEV-DO

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End ofSection 2

1xEVDO Operations

Documents

Modul2 EVDO Operation