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CDMA Channel Structure CBB_T02_E2 ZTE University CDMA-BSS Team

CDMA2000 1x Channel Structure

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Page 1: CDMA2000 1x Channel Structure

CDMA Channel Structure

CBB_T02_E2

ZTE University

CDMA-BSS Team

Page 2: CDMA2000 1x Channel Structure

Main Content

The forward channels in IS-95

The reverse channels in IS-95

CDMA Call Processing

New Channels in CDMA20001X

Page 3: CDMA2000 1x Channel Structure

IS-95A Channels

Page 4: CDMA2000 1x Channel Structure

Pilot Channel

•Used by the mobile station for initial system acquisition•Transmitted constantly by the base station•The same Short PN sequences are shared by all base stations, Each base station is differentiated by a phase offset•The function of Pilot channel is to search the serving sectors

•Used by the mobile station for initial system acquisition•Transmitted constantly by the base station•The same Short PN sequences are shared by all base stations, Each base station is differentiated by a phase offset•The function of Pilot channel is to search the serving sectors

Ec

Io

Energy of received pilot alone

Total energy received

Ec/IoMeasures the “strength” of the pilot

Ec/IoMeasures the “strength” of the pilot

Page 5: CDMA2000 1x Channel Structure

Sync Channel

(Acquired Pilot)

Sync Channel

•Used to provide essential system parameters

•Mobile Station re-synchronizes at the end of every call

•Used to provide essential system parameters

•Mobile Station re-synchronizes at the end of every call

Page 6: CDMA2000 1x Channel Structure

Sync Channel - continued

MSG_TYPE (‘00000001’)MSG_TYPE (‘00000001’)

P_REVP_REV

MIN_PREVMIN_PREV

SIDSID

NIDNID

PILOT_PNPILOT_PN

LC_STATELC_STATE

SYS_TIMESYS_TIME

LP_SECLP_SEC

LTM_OFFLTM_OFF

DAYLTDAYLT

PRATPRAT

CDMA_FREQCDMA_FREQ

88

88

88

1515

1616

99

4242

3636

88

66

11

22

1111

Field Length(bits)

Total : 170

System IDNetwork IDShort PN offset indexLong PN code statusSystem Time

Paging channel rateCDMA frequency assignment

Page 7: CDMA2000 1x Channel Structure

Sync Message Parameters

Message Type (MSG_TYPE) – Identifies this message and determines its structure (set to the fixed value of ‘00000001’)

Protocol Revision Level (P_REV) – Shall be set to ‘00000001’Minimum Protocol Revision Level (MIN_P_REV) – 8-bit unsigned integer identifying the

minimum protocol revision level required to operate on the system. Only mobile stations that support revision numbers greater than or equal to this field can access the system.

System ID (SID) – 16-bit unsigned integer identifying the systemNetwork ID (NID) – 16-bit unsigned integer identifying the network within the system (defined

by the owner of the SID)Pilot PN Sequence Offset Index (PILOT_PN) – Set to the pilot PN offset for the base station

(in units of 64 chips), assigned by the network plannerLong Code State (LC_STATE) – Provides the mobile station with the base station long code

state at the time given by the SYS_TIME field, generated dynamicallySystem Time (SYS_TIME) – GPS system-wide time as 320 ms after the end of the last

superframe containing any part of this message, minus the pilot PN offset, in units of 80 ms, generated dynamically

Page 8: CDMA2000 1x Channel Structure

Sync Channel MessageParameters (cont.)

Leap Seconds (LP_SEC) – Number of leap seconds that have occurred since the start of system time (January 6, 1980 at 00:00:00 hours) as given in the SYS_TIME field, generated dynamically

Local Time Offset (LTM_OFF) – Two’s complement offset of local time from system time in units of 30 minutes, generated dynamically

Current local = SYS_TIME – LP_SEC + LTM_OFFDaylight savings time indicator (DAYLT) – Determined by the network

planner1 if daylight savings in effect in this base station0 otherwise

Paging Channel Data Rate (PRAT) – The data rate of the paging channel for this system, determined by the network planner

00 if 9600 bps01 if 4800 bps

CDMA Frequency Assignment (CDMA_FREQ)

Page 9: CDMA2000 1x Channel Structure

Paging Channels

Paging Channel

Used by the base station to transmit system overhead informationand mobile station-specific messages.

Used by the base station to transmit system overhead informationand mobile station-specific messages.

There is one paging channel per sector per CDMA carrier

The Paging Channel uses Walsh function 1

Two rates are supported: 9600 and 4800 bps

Page 10: CDMA2000 1x Channel Structure

Paging Channel - continued

Mobile-Station-Directed Messages

Mobile-Station-Directed Messages

OverheadMessages

OverheadMessages

Access Parameters MessageAccess Parameters Message

System Parameters MessageSystem Parameters Message

CDMA Channel List MessageCDMA Channel List Message

Extended System Parameters MessageExtended System Parameters Message

Extended Neighbor List MessageExtended Neighbor List Message

ConfigurationParameterMessages

ConfigurationParameterMessages

Global Service Redirection MessageGlobal Service Redirection Message

PagingMessagesPaging

Messages

ACC_MSG_SEQ

CONFIG_MSG_SEQ

Page 11: CDMA2000 1x Channel Structure

Paging Channel Time Slot Structure

7

6

5

4

3

2

1

0

SCI 163.84 s

T = 2 SCI

SCI = Slot Cycle IndexT = Slot Cycle Length in 1.28 s unitsHow often: 1.28* T 80 ms

1.28 s

Page 12: CDMA2000 1x Channel Structure

CDMA Forward Traffic Channels

Forward Traffic ChannelForward Traffic Channel

Sync

Paging

Forward Traffic Channel

Forward Traffic Channel

Pilot

CDMA Cell Site

Used for the transmission of user and signaling information to aspecific mobile station during a call.

Maximum number of traffic channels: 64 minus one Pilot channel, one Sync channel, and 1 Paging channel.

This leaves each CDMA frequency with at least 55 traffic channels.Unused paging channels can provide up to 6 additional channels.

Page 13: CDMA2000 1x Channel Structure

CDMA Forward Channels

BTS (1 sector)MSC BSC

FECWalsh #1

Sync FECWalsh #32

Walsh #0

FECWalsh #12

FECWalsh #23

FECWalsh #27

FECWalsh #44

Pilot

Paging

Vocoder

Vocoder

Vocoder

Vocoder

Other users

Trans-mitter,

Sector X

Σ

I QPN120

Page 14: CDMA2000 1x Channel Structure

Main Content

The forward channels in IS-95

The reverse channels in IS-95

CDMA Call Processing

New Channels in CDMA20001X

Page 15: CDMA2000 1x Channel Structure

Reverse Access Channels

Access channel

Used by the mobile station to:Initiate communication with the base stationRespond to Paging Channel messages

Has a fixed data rate of 4800 bps

Each Access Channel is associated with only one Paging Channel

Page 16: CDMA2000 1x Channel Structure

CDMA Reverse Traffic Channels

Reverse Traffic Channel

Used when a call is in progress to send:Voice traffic from the subscriberResponse to commands/queries from the base station Requests to the base station

Page 17: CDMA2000 1x Channel Structure

Reverse Channels Generation and Demodulation

MSC BSC BTS (1 sector)

Channel Element

Access Channels

Vocoder

Vocoder

Vocoder

Vocoder

Receiver,Sector X

Channel Element

Channel Element

Channel Element

Channel Element

Long Code Gen

Long Code Gen

Long Code Gen

Long Code Gen

Long Code Gen

其它用户

UserLongCode User

LongCode User

LongCode

UserLongCode

UserLongCode

UserLongCode

•Each mobile is uniquely identified by the User Long Code, which it generatesinternally.•All mobile stations transmit simultaneously on the same 1.25 MHz wide frequency band.

•Each mobile is uniquely identified by the User Long Code, which it generatesinternally.•All mobile stations transmit simultaneously on the same 1.25 MHz wide frequency band.

•Any nearby BTS can dedicate a channel element to the mobile station and successfully extract its signal.

•Any nearby BTS can dedicate a channel element to the mobile station and successfully extract its signal.

Page 18: CDMA2000 1x Channel Structure

Main Content

The forward channels in IS-95

The reverse channels in IS-95

CDMA Call Processing

New Channels in CDMA20001X

Page 19: CDMA2000 1x Channel Structure

CDMA MS Call Processing

Power-UpPower-Up

InitializationInitialization

IdleIdle

SystemAccess

SystemAccess

TrafficTraffic

Mobile station has fully acquired

system timing

Mobile station receives a Paging Channel message requiring ACK or response, originates a call, or

performs registration

Mobile station is directed to a Traffic Channel

Mobile station ends use of the Traffic Channel

Mobile station receives an ACK to an Access Channel transmission

other than an Origination Message or a Page Response Message

Mobile station is in idle handoff with NGHBR_CONFG equal to

‘011’ or is unable to receive Paging Channel Message

Page 20: CDMA2000 1x Channel Structure

Main Content

The forward channels in IS-95

The reverse channels in IS-95

CDMA Call Processing

New Channels in CDMA20001X

Page 21: CDMA2000 1x Channel Structure

CDMA2000-1X New Features

High speed 307.2 kbps packet data capabilities;

Increased mobile standby battery life;

Total backward compatibility to reuse switch and call processing features;

CDMA2000 1x RF Capacity

Page 22: CDMA2000 1x Channel Structure

CDMA2000 1xRtt Channels

Page 23: CDMA2000 1x Channel Structure

1x New Channels in Commercial Network

IS-95B built on the IS-95A channels, and introduced two new channelsFundamental channel was the same as IS-95A traffic channelSupplemental code channels assigned to support rates above 14.4Kbps

IS-2000 1xRTT continue to build on the IS-95 channelsIS-95 channels continue to be supported in IS-2000 to support IS-95 mobiles

Pilot channel Sync channel Paging channel Access channelForward Traffic Channel Reverse Traffic Channel

Supplemental channel (F-SCH) Supplemental channel (R-SCH)Quick Paging channel (F-QPCH) Reverse Pilot channel (R-PICH)

Forward Reverse

IS-95A

1xRTT

Page 24: CDMA2000 1x Channel Structure