CDMA 120 – cdmaOne and CDMA2000 Concepts and Terminology phần 10 pot

CDMA 120 Section 8-35cdma university Forward Link Operation Variable rate Full, 1/2, 1/4, 1/8 Forward Link Operation The figure above shows the operation of the F-FCH, F-SCH1, and F-DCCH

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CDMA 120 Section 8-35

cdma university

Forward Link Operation

Variable rate (Full, 1/2, 1/4, 1/8)

Forward Link Operation

The figure above shows the operation of the F-FCH, F-SCH1, and F-DCCH channels The

scheduled rate of the F-SCH1 varies as a function of time, as does the rate of the F-FCH In theexample above, the F-DCCH channel is used to schedule the data rate of the F-SCH1 and is

operated in Discontinuous Transmit (DTX) mode

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cdma university Reverse Link Characteristics

z Channels are primarily code multiplexed– Separate channels used for different Quality ofService (QoS) and Physical Layer characteristics

z Code multiplexed channels are orthogonalized byWalsh functions and I/Q split so that performance isequivalent to BPSK

– By restricting alternate phase changes of thecomplex scrambling sequence, power peaking isreduced (1 dB improvement) and side lobes arenarrowed

Notes

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cdma university Reverse Link Characteristics (continued)

z Code multiplexed channels– Walsh sequences separate Physical Channels

z Forward Error Correction– Convolutional codes (K=9) are used for voice and data– Turbo codes (K=4) are used for high data rates onSupplemental

z Fast Reverse Power Control– 800 Hz update rate

z Frame lengths– 5 ms, 10 ms, 20 ms, 40 ms, and 80 ms frames

Notes

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Enhanced Access Channel Operation

Reverse Common Control Channel Operation

Reverse Traffic Channel Operation (RC 3 to 6)

Reverse Fundamental Channel

Reverse Pilot Channel

0 to 7 Reverse Supplemental Code Channels

Enhanced Access Channel

Reverse Common Control Channel

0 or 1 Reverse Dedicated Control Channel

0 or 1 Reverse Fundamental Channel

0 to 2 Reverse Supplemental Channels

Reverse Power Control Subchannel Backward-Compatible Channels

Reverse Link Channels

The CDMA2000 Reverse Link Channels are:

The Access Channel and Reverse Supplemental Channel are retained for backward compatibilitywith TIA/EIA-95A/B For Radio Configurations 1 and 2, the channel structure for the ReverseFundamental Channel and Reverse Supplemental Channel is the same as the channel structure ofRate Set 1 and Rate Set 2 used in TIA/EIA-95A/B

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Enhanced Access Channel Operation

Reverse Common Control Channel Operation

Reverse Traffic Channel Operation (RC 3 to 6)

Reverse Fundamental Channel

Reverse Pilot Channel

0 to 7 Reverse Supplemental Code Channels

Enhanced Access Channel

Reverse Common Control Channel

0 or 1 Reverse Dedicated Control Channel

0 or 1 Reverse Fundamental Channel

0 to 2 Reverse Supplemental Channels

Reverse Power Control Subchannel

Common Channels

Dedicated Channels

Reverse Common and Dedicated Channels

Reverse Link Common Channels are used by multiple mobiles primarily for a brief exchange ofinformation between a mobile and a Base Station The Reverse Link Common Channels are:

Reverse Link Dedicated Channels are assigned to a single mobile for the duration of a call TheReverse Link Dedicated Channels include:

The Reverse Pilot Channel is used with both Common and Dedicated Channels

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cdma university Illustration of Reverse Link Operation

Reverse Link Operations

The Reverse link Pilot is always active and different channels may be transmitted as long as themobile transmitter has sufficient power The channel power is a function of the data rate, FEC, andframe length

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1 Fundamental Channel (FCH) or

1 Dedicated Control Channel (DCCH) + up to 2 Supplemental Channels (SCH)

FCH or DCCH

Data Multiplexing

CDMA2000 can multiplex data from multiple sources (e.g., signaling, voice, and data) onto one ormore Physical Channels Data can be multiplexed in one or two Supplemental Channels

Mode A is the TIA/EIA-95 A/B compatible mode It includes Rate Set 1 and 2 It uses a

Fundamental Channel (FCH) that carries signaling and primary and/or secondary traffic

In addition, up to 7 Supplemental Code Channels (SCCH) can be used to support the TIA/EIA-95Medium Data Rate (MDR) services

Mode B is new for CDMA2000 It uses a Fundamental Channel (FCH) and/or a Dedicated Control

Channel (DCCH) to carry signaling and primary and/or secondary traffic In addition, up to 2

Supplemental Channels (SCH), each of which operates at rates up to 1036.8 kbps, are used to carrydata

Note: The term “Supplemental Channel” is used in both TIA/EIA-95 and CDMA2000 to describe

two completely different channels To alleviate confusion, CDMA2000 channels that are

backward-compatible with the TIA/EIA-95 “Supplemental Channel” are referred to as

“Supplemental Code Channels.” Thus the CDMA2000 “Supplemental Code Channel” is the same

channel as the TIA/EIA-95 “Supplemental Channel.”

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cdma university Access Channel Procedures

F-CACH

R-EACH R-CCCH

CDMA2000Enhanced AccessProcedures

TIA/EIA-95 A/BCompatibleAccess Procedures

F-CCCH F-BCCH

BTS BTS

R-ACH

F-PCH

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TIA/EIA-95 A/B Compatible Access Channel Procedures

If the mobile monitors the Paging Channel (F-PCH), then its access attempts are made on the

Access Channel (R-ACH) These procedures are identical to TIA/EIA-95 A/B access procedures

CDMA2000 Enhanced Access Channel Procedures

If the mobile monitors the Forward Common Control Channel (F-CCCH) and Broadcast ControlChannel (F-BCCH), then its access attempts are made on the Enhanced Access Channel

(R-EACH) using the CDMA2000 enhanced access procedure

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z 1xEV–DO is a spectrally efficient solution optimizedfor high-speed wireless Internet access

– 1x = single 1.25 MHz spaced carrier– EV = EVolution

– DO = Data Optimized (no voice traffic)– 1xEV-DO systems have their own dedicated RFChannel (frequency assignment)

– Internet working with CDMA2000 1x system issupported by means of hard handoff

z 1xEV-DO is standardized as IS-856

What is 1xEV-DO?

1xEV-DO (also known as IS-856) systems are optimized for packet data and not voice This

permits peak data rates of 2.4 Mbps on the Forward link and 153 kbps (per user) on the Reverselink IS-856 represents a wireless alternative to cable modems and DSL

IS-856 terminals operate on their own dedicated carriers, separate from cdmaOne or CDMA2000carriers IS-856/CDMA20001x dual-mode operation is accomplished by the dual-mode terminalperiodically monitoring traffic on the CDMA2000 frequency

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cdma university 1xEV-DO Is Data Optimized

z 1xEV-DO is designed to optimize packet dataservices

z Data and Voice have distinctly different requirements– Latency

– Bit error rate– Throughput– Forward/Reverse data rates

z Using a single technology to carry both voice anddata is a compromise

z Voice and data are carried more efficiently if separatenetworks are used

Data Optimized

1xEV-DO is designed to be optimized for packet data services and avoids the compromises

involved in supporting both data and voice services Data and voice have fundamentally differentrequirements

Voice tends to be:

Data tends to be:

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z 1xEV-DO Forward link rates are from 38.4 kbps

z Forward/Reverse data rates are asymmetricreflecting the difference in traffic levels in eachdirection

Data Rates

The 1xEV-DO maximum Forward link data rate is much higher than that for the Reverse link This

is consistent with the typical data applications (e.g., Web page downloads)

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cdma university 1xEV-DO and IS-2000 Family Overlay

174AA_01.emf

1xEV-DO and IS-2000 1x IS-2000 1x

Family Overlay

1xEV-DO is designed to operate at a separate CDMA carrier frequency (i.e., frequency

assignment) from an existing IS-95 or CDMA2000 1x system When overlaid with an IS-95 orCDMA2000 1x system, 1xEV-DO can deployed incrementally to follow demand on its own

dedicated frequency assignment

1xEV-DO has the same chip rate, link budget, power requirement, channel bandwidth, and

coverage as IS-95 or CDMA2000 1x This means that no changes are required to existing networkplans and that the same cell sites, towers, and antennas can be used

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Comparison of Forward Links

The Forward link structure for 1xEV-DO is very different from that of IS-95 or CDMA2000 1x.The Forward link in 1xEV-DO is Time Division Multiplexed (TDM) as opposed to Code DivisionMultiplexed (CDM), as in IS-95 or CDMA2000 1x

For 1xEV-DO, each user is assigned a period of time during which only its data is transmitted atfull power, on the Forward link This eliminates unused transmit power margin Time slots arelikewise dedicated to sending the Pilot and control information (which includes the Paging andSync Channel functions) This is in contrast to IS-95 or CDMA2000 1x where the Pilot, Sync, andPaging are sent continuously

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cdma university Forward Link Slot Structure

178AA_01.emf Idle Slot

Active Slot

Data 400 Chips

1/2 Slot 1,024 Chips 1,024 Chips1/2 Slot

Pilot 96 Chips

MAC 64 Chips

Pilot 96 Chips

MAC 64 Chips

Pilot 96 Chips

MAC 64 Chips

Pilot 96 Chips

MAC 64 Chips

1 slot 1.66 ms

Note: The 64-chip MAC carries the Reverse Power Control (RPC) Channel and Reverse Activity Channel.

Forward Link Slot Structure

The figure above shows time division multiplexing on the Forward link of the various channels(i.e., Preamble, Pilot, MAC, and Data) for a one-slot case for the 614.4 kbps data rate In 1xEV-DO

a slot is 1.66 ms in length

When there is no traffic on the Forward Traffic Channel, an idle slot is sent An idle slot consistsmerely of the Pilot and MAC Channels Transmission of idle slots decreases interference to othercells on the Forward link

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Comments/Notes

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Comments/Notes

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MMT98010118B-rev.emf

CDMA2000

and

Section 1: Course Introduction

This section provided an overview of the entire course with overall learning objectives

Section 2: Background

This section identified and discussed multiple access techniques The CDMA approach was

reviewed through a discussion of its architecture, general modulation scheme, and some of itspractical applications Necessary analog/RF and digital concepts were briefly reviewed

Section 3: Codes in CDMA

This section described the codes used in generating the cdmaOne signals Pseudorandom Noisecodes and orthogonal (Walsh) codes were defined and discussed

Section 4: Physical Layer

This section described the processes involved in the generation of the cdmaOne waveforms andsome of the rationale for the design of those waveforms

Section 5: Attributes and Techniques of CDMA

This section provided a detailed discussion of the attributes and techniques of CDMA systems in

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MMT98010118B-rev.emf

CDMA2000

and

Section 6: cdmaOne Call Processing and Registration

This section described the call processing and registration processes supported by cdmaOne

systems

Section 7: cdmaOne Handoffs

This section described the handoffs supported in a cdmaOne system and the signaling involved inthe control of handoffs The discussion covered several kinds of handoffs, including “idle,”

“access,” “soft,” “softer,” and “hard.” In addition, the pilot searching process was briefly

discussed

Section 8: CDMA2000 Overview

This section provided an overview of CDMA2000 based on the concepts covered in the discussion

of cdmaOne The overview included a discussion of new common and dedicated channels, transmitdiversity, radio configurations, quasi-orthogonal functions, handoffs, and power control as well as

a brief discussion of 1xEV-DO high-speed wireless packet data technology

Section 9: Course Summary

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Comments/Notes

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Comments/Notes

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