Cdma2000-1x Ev Do

Introduction to 1X EVIntroduction to 1X EV--DODO

AgendaAgenda

• Overview

• Forward link structure

• Reverse link structure

• Channel measurement & control

– Link adaptation scheme

– Reverse power control

• Scheduler

• Field/ simulation test results

OverviewOverview

• IS-856, also referred as 1X EV-DO, is a high speed wireless data technology

– It is a system optimized for Data

• IS-856 is the standard specification for cdma2000 high rate packet data systems

• IS-856 objectives

– Designed for high speed wireless packet data service

– Provides internet connectivity to mobile and fixed users

– Compatible with existing (IS-95) and cdma2000 CDMA wireless network

Overview Overview ……

• Data and voice have distinctly different requirements

– Voice systems

» Need symmetric forward and reverse links

» Voice services are provided at a constant and low latency

» For voice, quality of service cannot be compromised, i.e.,Independent of coverage

– Data systems

» Demand faster forward links

» Data services seek to maximize sector throughput subject to a fairness constraint

» Can tolerate large latencies - more than in voice

» Data services need not be equal across coverage conditions

• Using a single technology to carry both voice and data is a compromise

1X EV1X EV--DO Data RatesDO Data Rates

• Dynamic data rates

• Defined depending on level of interference C/I

REV (kbps)

9.6, 19.2, 38.4, 76.8, 153.6

FWD (kbps)

38.4, 76.8, 153.6, 307.2,614.4, 921.6, 1228.8, 1843.2, 2457.6

• The actual throughput available to any one user depends on

– Total number of users

– Level of interference (C/I)

• Forward/Reverse data rates are asymmetric reflecting the difference in traffic levels in each direction

CompatilityCompatility With ISWith IS--95/1X Network95/1X Network

• 1X EV-DO is designed to operate in Cellular or in PCS band on a separate CDMA channel

– i,e., Frequency assignment same as in existing IS-95/1X system

• 1X EV-DO has same chip rate, link budget, power equirement, channel bandwidth, and coverage as IS-95/1X

• No changes(?) required to existing network plans

-- i,e., Coverage different with 2G

• Same cell sites, towers, and antennas can be used(중계기연동미확인)

• 1X EV-DO sites can be selectively deployed into IS-95/1X

-- 1X EV-DO type ( Mixed,Stand-alone,Smart,Pico …)

1X EV1X EV--DO and ISDO and IS--95/1X Overlay95/1X Overlay

IS-95 A/B

cdma2000/IS-95

cdma2000/EV-DO

1X EV1X EV--DO Vs. ISDO Vs. IS--95/1X Spectrum95/1X Spectrum

ISIS--9595 1X EV1X EV--DODOThe same chip rate (1.2288 MHz) and FIR filter is used for

HDR, resulting in similar spurious emissions performance.

Forward Link

1X EV1X EV--DO Vs. ISDO Vs. IS--95/1X Forward Link95/1X Forward Link

Feature of 1X EVFeature of 1X EV--DODO

• Time division multiplex on Forward Link

• Larger frame size(IS-95 A/B,cdma2000 20ms vs 1X EV-DO 26.66ms)

• Asymmetry in Forward Link and Reverse Link structures

• Turbo coding and decoding on Forward Link and Reverse Link

– Large latencies allow turbo codes to be used

– Allows operation at lower Eb/No and therefore lower C/I and lower interference levels

• Reverse rate indicator (RRI) and data rate control (DRC) channels on the RL

• Reverse activity (RA) channel on the Forward Link

• Implementation of data rate control & ARQ schemes

AgendaAgenda

• Overview






• Scheduler


Forward LinkForward Link

Forward Link/Reverse Link는 Physical Layer기준으로Channel을구분한것.

Forward Link/Reverse Link는 Physical Layer기준으로Channel을구분한것.

Forward Channel StructureForward Channel Structure• Forward channel structure is of a time multiplex of the following channels:

– Pilot channel (Common Channel)

» Used by AT for all the following:

• Initial acquisition

• Phase & timing recovery

• Coherent demodulation and maximal ratio combining

• Means to estimate receive C/I for forward data rate control

– Medium access channel (MAC)(is not Common, only for specific user)

» Consists of two sub-channels:

• Reverse activity channel (RA): carries reverse activity bit (RAB) stream

• Reverse power control channel (RPC)

– Traffic channel (same as MAC channel)

» Carries user packets

– Control channel(is broadcasted or unicasted)

» Carries control messages and also carries user traffic

Forward Channel Structure Forward Channel Structure ……

• Idle slots

– Slots during no traffic/control data are referred to idle slots

– During idle slots, sector transmits only Pilot & MAC channels

• Forward link parameters

– Forward channel is defined in frames of length 26.66 ms aligned to PN rolls with zero offset PN sequences(may be for Frame Sync)

– Each frame is divided into 16 slots of length 1.66 ms

– Each slot consists of 2048 PN chips

– Packet size varies from 1 slot to 16 slots depending on the data rate and coding rate/modulation scheme

Forward Slot WaveformForward Slot Waveform

Forward Link Pilot ChannelForward Link Pilot Channel

• Pilot channel

– It is an unmodulated BPSK signal with in-phase component only

– Pilot channel is assigned walsh cover 0

– It is transmitted in a burst mode

» Each pilot burst has a duration of 96 chips centered at the midpoint of each half slot

– It is transmitted at full sector power

A

192 PN Chips per slot

Forward Link MAC ChannelForward Link MAC Channel

• MAC channel

– MAC is a CDM of RPC, and RA channels

– Composed of 64 code channels

» Each user code channel is identified by a MAC index(same as Walsh code)

– Orthogonally covered by 64-ary walsh channels

– BPSK modulated

– MAC symbol walsh covers are repeated 4 times per slot

• Two bursts of length 64 chips are transmitted twice every slot immediately preceding and following a pilot burst

B

Forward Link MAC Channel Forward Link MAC Channel ……

MAC Channel and Preamble Use Versus MACIndex

MACIndex MAC Channel use Preamble use

0 and 1 Not used Not used

2 Not used 76.8kbps control channel

3 Not used 38.4kbps control channel

4 RA channel Not used

5 ~ 63 RPC channel transmission Forward Traffic channel transmission

Forward Link PreambleForward Link Preamble

• Preamble channel

– A preamble sequence is

time multiplexed into first

slot of each traffic or control

channel packet

– Mainly to assist every AT in

identifying forward traffic

data or control channel information

• Preamble sequence is

covered by a 32 bit biorthogonal

sequence

• Repeated several times

based on data rate as before

Forward Link PreambleForward Link Preamble……

DATAMAC

Pilot64bit

MAC

DATA DATAMAC

Pilot64bit

MAC

DATA

Preamble /w MACIndex

1slot (2048chips)[1.66ms]

C

1024 chips 1024 chips

Basicaly, AT must be decode the Preamble of Control/Traffic Channel.

Forward Link Traffic ChannelForward Link Traffic Channel

• Traffic channel

– Payload consists of packets in blocks of fixed size based on data rate

– Turbo coded

– Output of encoder is scrambled and interleaved

– Interleaved symbols are QPSK/8PSK/16-QAM modulated

– Modulated symbols are repeated

– Demultiplexed to form 32 pairs of in-phase and quadrature phase parallel streams

Forward Link Control ChannelForward Link Control Channel

• Control channel

– Transmits broadcast messages and AT directed messages

– Fixed rate @ 38.4 kbps or 76.8kbps

– Modulation characteristics are same as traffic channel

– Preamble of control channel is covered by 32-ary biorthogonal sequence

» The specific index of preamble distinguishes control channel from traffic channel

– The control channel cycle is a 426.66 ms cycle(256 slots)

– A control channel capsule is included at the beginning of every control channel cycle

termed as synchronous capsule

Forward Link Control Channel Forward Link Control Channel ……

D

Control Channel Structure

Reserved(“4”bit)

Offset(“2”bit)

LastPacket(“1” bit)

SynchronousCapsule(“1” bit)

Synchronous Capsule bit가 “1”이면

Control Channel 시작이고,

Last Packet bit 가

“1”일때까지Monitoring 한다.Control Channel Header Structure

1X EV1X EV--DO Coding SchemeDO Coding Scheme

• Turbo encoded packet is scrambled and block interleaved

• High C/I

– Number of code symbols in first slot may be less than total code symbols in the packet

» Higher effective code rate is achieved by truncation of parity bits

– Coding gains due to incremental transmission of parity bits

• Low C/I

– All code symbols are transmitted followed by repetitions

– Coding gains by simple repetition of a basic 1/5 rate code.

Forward Channel StructureForward Channel Structure

TD

MT

DM Qudrature

SpreadingQudratureSpreading

I

Q

BasebandFilter

BasebandFilter

BasebandFilter

BasebandFilter

∑

cos(2πft)

sin(2πft)

A

B

C

D

Forward modulation wave

A,B,C,D는그순간에한 point만점유한다.

AgendaAgenda

• Overview






• Scheduler


Reverse Link StructureReverse Link Structure

Reverse Link Physical LayerReverse Link Physical Layer

• Reverse link parameters:

– Reverse channel frames are 26.66 ms in length aligned to PN rolls of the short code PN sequences

– Packet size is fixed at 26.66..Ms

– Reverse link PN chip rate For every channel is 1.2288 Mcps on both I and Q basebandstreams

• Output power characteristics are similar to IS-95 A/B

– Access channel operation is similar to IS-95 A/B

– Closed & open loop power controls the mean output power of pilot and MAC channels

– The power levels for data are adjusted based on selected data rate

Reverse Channel StructureReverse Channel Structure

• Traffic channel

– In-phase component is a CDM of pilot/RRI and ACK Channels

– Quad-phase component is a CDM of DRC and data Channels

– Independent gains on DRC and ACK channel relative to pilot

– DRC gain range (-9dB to +6dB)

– ACK gain range (-3dB to +6dB)

• Access channel

» Pilot channel

» Data channel(UATI Request, UATI Complete, Connection Request)

– In-phase component consists of the pilot channel

– Quad-phase component consists of the data channel

Pilot/RRI Channel (Reverse Traffic Channel)Pilot/RRI Channel (Reverse Traffic Channel)• Pilot channel

– Unmodulated symbols w/ binary value 0 @ 1.2288 Mcps

• RRI channel

– Reports data rate of the current reverse link data packet

» Represented by 3-bit RRI symbol, sent once per data packet

» One-to-one mapped to reverse data rates

– Each RRI symbol maps into a 7-bit codeword

– Codeword is repeated 37 times

– Time multiplexed with pilot symbols on every slot

– Time multiplex of pilot and RRI spread by walsh cover W016

ACK Channel

• Used to inform AN whether the data packet transmitted on Forward Link was received successfully or not

• One bit ‘0’ or ‘1’ is transmitted per half slot

• Transmitted over the first half of the slot

• Repetition factor = 128

• Walsh cover is W48

• Shall last for 1024 chips/ active half slot

DRC ChannelDRC Channel

• DRC channel

– Used to request a specific data rate on forward link(DRC value)

» This is a 4-bit DRC symbol

» One-to-one mapped to requested data rates

– Requests a specific sector to transmit data to the AT(DRC cover)

» This is a 3-bit walsh cover

» One-to-one relation to the sectors in active set

– Estimated C/Is of active set pilots are mapped to DRC values

– DRC symbols and DRC walsh cover are transmitted at a rate of 600/DRClength per sec

» One DRC symbol is sent per DRClength number of slots

» During transmission DRC symbol is repeated DRClength times to yield 600 symbols per second

DRC ChannelDRC Channel

• DRC channel

– Used to request a specific data rate on forward link

» This is a 4-bit DRC symbol

» One-to-one mapped to requested data rates

– Requests a specific sector to transmit data to the AT

» This is a 3-bit walsh cover

» One-to-one relation to the sectors in active set

– Estimated C/Is of active set pilots are mapped to DRC values

– DRC symbols and DRC walsh cover are transmitted at a rate of 600/DRClength per sec

» One DRC symbol is sent per DRClength number of slots

» During transmission DRC symbol is repeated DRClength times to yield 600 symbols per second

Data ChannelData Channel

• Data Channel

– Reverse traffic data can be transmitted at following rates:

» 9600, 19200, 38400, 76800, 153600 bps

– Data Transmitted on Reverse Traffic Channel is

» Turbo encoded

» Block interleaved

» Sequence repeated &

» Orthogonally spread by W24

Access Channel StructureAccess Channel Structure

• Access channel

– Preamble part (length is specified by upper layer protocol)

– Access channel data packet (2 frames long) @ 9.6kbps

– Pilot channel: unmodulated symbols w/ binary value 0 @1.2288 Mcps

– No MAC channel during access probe transmissions

Access channel slot for preamble length of 2 frames

Access Channel Structure Access Channel Structure ……

Access Probe Structure

Reverse Traffic Channel Data Rate ControlReverse Traffic Channel Data Rate Control

• Initially, AT set Current Limit 9.6kbps

• After Broadcast/UnicastRateLimit message received, AT update Current Limit

• AT changes reverse data rate on three factors.

- Current Rate : trans limit rate on reverse at present.

- Combined Busy Bit

>> If the last time RAB is “1” , Combine Busy Bit “1”.Otherwise “0”

- Condition : random number between 1 and 0

• In according to Condition value, set Maxrate to Maxratetrue value. Otherwise set Maxratefalse.

• Tabel is next….

Reverse Traffic Channel Data Rate Control Reverse Traffic Channel Data Rate Control ……

Determination of Max rate

Reverse Channel StructureReverse Channel Structure

∑ACK ChannelGain

DATA ChannelGain

DRC ChannelGain

∑

Q

I

Access Channel

Reverse Traffic Channel

AgendaAgenda

• Overview






• Scheduler


Link Adaption Scheme

• All base stations transmit a full power pilot all the time

• Access Terminal (AT) measures the C/I on each pilot in the active set every slot (1.67 ms).

• Access Terminal predicts the C/I for the next packet

• Requests the highest rate it can decode at that C/I for a given error performance

• Rate requests are sent on the data rate control (DRC) channel in the reverse link.

– Requests are directed at a particular access point (AP)

– Update Rate depends on handoff condition

– Nominally updated every slot (600Hz)

Link Adaption Scheme …

• Requested data rate determines

– Modulation scheme (QPSK, 8-PSK, 16-QAM)

– Code Rate

– Preamble Length

– Maximum # of slots required for transmission

• If the AP chooses to serve the AT then the AT knows exactly what rate it would be served at

– No blind rate detection

• With multiple terminals, a scheduler determines the order in which terminals are served.

Link Adaption Scheme…

• Only 1 base station transmits to an AT at a time

– Reduced forward link interference to users of other base stations

• A base station transmits to only 1 AT at a time

• Base station interference is minimized when user queues are empty

EVEV--DO Hand Off AlgorithmDO Hand Off Algorithm

• Because AT received the data from only one AP,it can be soft handoff between APs in 1X EV-DO.

• It means that For ware Link is not supported for soft handoff, but Reverse Link can be.

• Reverse Link soft handoff algorithm.

-- AT switch rapidly from one AP to another AP

-- More than one AP receive AT’s transmissions, and frame selection is made

EVEV--DO Hand Off ExampleDO Hand Off Example

EVEV--DO Hand Off ExampleDO Hand Off Example

Reverse Power ControlReverse Power Control

• Minimize AT transmit power to achieve acceptable PER.

• Inner power control – Fast loop between AT and AN,AN sends UP/DOWN commands @ 600Hz to keep AT Tx power at PC setpoint

• Closed loop power control

– BTS based

• Outer loop power control

– Sets the PC setpoint to target a 1% PER

– Changes when a packet is received

– BSC based

Inactive state : initial state

No data : connection setup, but no data. Time based

(Frame Length time based)

Normal : data exchanging, good or bad frames based

Data start : in No data state,if good frame, PCT down

in No data state,if bad frame, Normal state

Open Loop Open Loop vsvs Outer LoopOuter Loop

Forward Link Throughput 1-path Rayleigh 3km/h fading

PER with Outer Loop Rate ControlPER with Outer Loop Rate Control

AgendaAgenda

• Overview






• Scheduler


SchedulerScheduler

• Proportional fairness vs Round-Robin

• Exploits user diversity

• Adapts to longer term channel variation of users

• Takes advantage of local peaks in requested rate

• Always serves someone if possible

• For a given user

– Fraction of time lower rates are served is LOWER than the fraction of time they are requested

– Fraction of time higher rates are served is HIGHER than the fraction of time they are requested

Scheduler AlgorithmScheduler Algorithm

• Round-Robin

-- Not used• Proportional Fairness

-- user selection DRCi(n)/Ri(n)

Ri(n) : Serviced Rate.

Agenda

• Overview






• Scheduler


Simulated Sector ThroughputSimulated Sector Throughput

Single RX ANTSingle RX ANT’’ Throughput ChartThroughput Chart

Call processing ProcedureCall processing Procedure

• Idle State, Connected State

• Origination Procedure

• Handoff Procedure

• Senario

• 1X EV-DO Protocol Layer

Power up ProcedurePower up Procedure

• Power On ( Remain on idle state )- Initialization state

. Inactive state

. Network determination

. Pilot acquisition

. Synchronization(network. acquired)

>> Activate Control Channel(MAC Layer) on AT

>> Sync message, QuickConfig, SectorParam

- Idle state

. Monitor state

. Connection set_up state

Power up Procedure (Idle state) Power up Procedure (Idle state) ……

Power up

BTS

• Inactivate state

• Network determination

• Pilot acquisition

• Synchronization

QuickConfig,SectorParam

Sync message

• Monitor state

> UATI Request(AC)

> UATI Response(CC)

: ColorCode,UATI024

> UATI Complete(AC)

• Connection setup state

> Connection Request(AC)

UATI Requset

UATI Response

UATI Complete

ConnectionRequest message

Initial state on Connection layer

Monitor state on connection layer

Connection setup state on connection layer

Power up (going on connected state) Power up (going on connected state) ……

BTS

ConnectionRequest

RU

P

RU

P

AC

MA

C

AC

MA

C

RT

CM

AC

RT

CM

AC

Routeupdate message

ACACK

TrafficChannelAssignment

Pilot+DRC

RTCAck

TrafficChannelComplete

Session Negotiation Start

DRCLength, DRCCover, FrameOffset, MACIndex….

ConnectionClose message

Connected state

Connection setup

Idle state

Call processing Procedure

• Idle StateConnected State



• Senario


Origination ProcedureOrigination Procedure

Only used LCP

MD5 algorithm used

(Challenge, ID, PASSWORD)

User authencification

Accounting start

LCP and IPCP. Assignment IP address to AT.


• Idle State, Connected State



• Senario


Handoff Procedure (Idle state)Handoff Procedure (Idle state)

BTSBTS

DRC(value(k+1), cover(k+1))

ForwardTrafficdata(MACIndex(j))

ForwardTrafficdata(MACindex(i))

DRC(value(k),cover(k))

ForwardTrafficdata(MACindex(i))

①

③

②

④

⑤

AT communicates with only one BEST sector

Pilot Strenth

Active set

A B

Active set

t


•• Idle State Connected StateIdle State Connected State

•• Origination ProcedureOrigination Procedure

•• Handoff ProcedureHandoff Procedure

•• SenarioSenario

•• 1X EV1X EV--DO Protocol LayerDO Protocol Layer

SenarioSenario (Hybrid AT)(Hybrid AT)

1. Senario 1

When AT is dormant state, AT moves from served BSC to another BSC.

• Senario 2

When AT is exchanging the data in 1X EV-DO BSC, it receive the voice page message from cdma2000 1X BSC.AT switch to cdma2000 1X BSC and contiues to receive data+voice in cdma2000 1X BSC.

3. Senario 3

When AT is exchanging the data in 1X EV-DO BSC, it initiates the voice call in cdma2000 1X BSC.AT switches to cdma2000 1X BSC and continues to exchange voice+data in cdma2000 1X BSC.

SenarioSenario (Hybrid AT) (Hybrid AT) ……

4. Senario 4

When AT resides in the coverage area of 1X EV-DO BSC, it transit to the Dormant state. The AT remains in 1X EV-DO BSC and monitor cdma2000 1X BSC common channel as well as 1X EV-DO Control Channel.

5. Senario 5

AT is the active or Dormant state of data service in 1X EV-DO BSC area.ATmoves from 1X EV-DO to cdma2000 1X BSC.

6. Senario 6

AT is the acitve or Dormant state of data service in cdma2000 1X BSC area. AT moves from cdma2000 1X BSC to 1X EV-DO area.

7. Senario 7

AT is exchange the data in 1X EV-DO area. it receive the SMS broadcast from cdma2000 1X BSC.


• Idle StateConnected State



• Senario


1X EV1X EV--DO Protocol LayerDO Protocol Layer

Important Layer

Session LayerSession Layer

• Session Management Protocol

Control Address Management Protocol and Session Configuration Protocol

• Address Management Protocol

Provides UATI assignment

UATI Request, UATI Assignment, UATI complete

• Session Configuration Protocol

Provides for the negotiation and configuration of the set of protocols during a session• Session Close Condition

1. AT can not be available for a period lager than the keep alive timer.

2..AT moves to different network.

3. AN sends SessionClose message.

•Keep Alive algorithm

1. This function is the maintenance between AT and AN sessions.

2. This algorithm runs only when no traffic data to/from AT/AN.

3. Keep alive timer is default 54hours

Connection LayerConnection Layer

• Air Link Management Protocol

Provides general state machine and state transition rules for connection layer

• Initialization State Protocol

Provides procedures for AT to acquire a serving network

CDMA channel selection, Pilot acquisition, Sync message

• Idle State Protocol

Monitors control channel and initiates a connection

Maintains Monitor state and Sleep state

• Connected State Protocol

Works while a connection is open

Processes Connection Close message

Connection LayerConnection Layer……

• Route Update Protocol

- Keeps track of AT’s location (Idle Handoff)

Distance-based

- Maintains AT’s radio link between different sectors (Active Handoff)

Pilot-strength-based

- Route Update Protocol substatesidle state Route Up date. Idle HO, Route Update. NetworkLost

Route Update. Active Setup dated, Route Update. Assignment rejected

Route Update. Connection LostConnected state

Connection LayerConnection Layer……

•Overhead Message Protocol

Provides overhead messages

Overhead Parameter Up To Date is “0”,if belows

1.AT has not any stored value for overhead parameter or Routupdate.IdleHO

2.SectorSignature is different from the last stored value

Quick Config message(every ControlChannel synchronous capsule)

sector signature included.

Sector Parameters message(at least every 3 ControlChannel)

1. Lat, Long, Routeupdate Radius, Neighbor Count ,Neighbor PN, Neighbor Channel Included, NeighborChannel

2. Neighbor Search Window Size, Neighbor Search Window offset….

• Packet Consolidation Protocol

Provides mux/demux of session layer packets

MAC LayerMAC Layer

• Rules to govern operation of main 1xEV-DO data channels.

• MAC Layer protocol for follow channelsControl Channel(8slots continuously)

PageSync: Every 3 control channel cycles (3*256 slots)Quick Config: Every control channel cycle Sector Parameters: Every 3 control channel cyclesAccess Parameters: Every 3 control channel cycles

Access ChannelForward Traffic ChannelReverse Traffic Channel

Thanks! & Thanks! & Suggestions!Suggestions!

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Cdma2000-1x Ev Do