6534Tdma Tutorial[1]

7/29/2019 6534Tdma Tutorial[1]

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TDMA

Tutorial



Outl in e o f Presentat ion

• Evolution of Technology

– AMPS to TDMA

• The TDMA Digital Control Channel

– Features and capabilities

– Technical description

• Services and design examples



TDMA Standards Overview

• EIA 553

– Analog AMPS-based technology platform

• IS-54B

– Introduces a TDMA digital traffic channel

and a new feature set

• authentication, calling number ID, messagewaiting indicator, and voice privacy.



TDMA Standards Overview - cont .

• TDMA

– Backwards compatible to IS-54B and EIA 553. Includes a

digital control channel and advanced features.

• TDMA Rev A

– Upbanded IS-136 for seamless cellular service between

800 MHz and 1900 MHz frequency bands, over the air

activation and programming services developed.

• TDMA Rev B

– Introduces a range of new features (broadcast SMS,

packet data etc.)



TDMA Standards Evolu t ion

1988 1990 1992 1994 1996 1998

Capacity

Services

Quality

Coverage

Cost

TDMA StandardsProcess Begins

IS-54 Adoptedby TIA/CTIA

TDMA in Commercial Service

TDMA Rev. 0

TDMA A plusEFRC

TDMA B



TDMA Traff ic Channel Struc ture

• Modulation

– p /4 DQPSK - differential quadrature phase shift keying.

– Across air bit rate = 48.6 Kbps.

• Frame Structure – TDMA frame = 40mS.

– Six 6.67 ms slots per frame, two slots used for full rate voice.

TDMA Slot Format

Sync SACCH Data CDVCC Data RSVD

TDMA Frame

40 ms



TDMA Speech Cod ing

• Speech and channel coding are important factors in

good voice quality. Other factors include: – System planning (handoff, reuse, coverage, etc.)

– Handset design

– Echo suppression, audio balancing, …

• Two speech codecs defined for TDMA – VSELP - Vector Sum Excited Linear Predictive

– ACELP - Algebraic Code Excited Linear Predictive

• VSELP – Originally defined for IS-54B - 80s Technology

• ACELP – Newly defined for TDMA - 90s Technology - “state of the art”

– Offers wireline voice quality in clean conditions



ACELP Channel Cod ing

Class-2 bits

Class-1 bits96

7

208

52

260260216

Coded

Class-1

bits

5 Tail bits

7-bit CRC

Computation

Rate 1/2

Convolutional

Coding

48 Most

Perceptually

Significant

Bits

S p e e c h C o d e r ( A C E L P )

P u n c t u r i n g

V o i c e C i p h e r

2 - s l o t i n t e r l e a v e r

codec 7.4kbps

codec + channel coding =

7.4kbps + 5.6kbps = 13kbps

40 msec

speech

frames

x and y

speech

frames

y and z



TDMA Voice Quali ty

EFRC vs. VSELP

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

C l e a n

1 7 d B 5 m p h

1 7 d B 3 0 m p h

1 7 d B 6 0 m p h

1 5 d B 5 m p h

1 5 d B 3 0 m p h

1 5 d B 6 0 m p h

1 3 d B 5 m p h

1 3 d B 3 0 m p h

1 3 d B 6 0 m p h

Test Condition

M O S EFRC

VSELP



Mobi le Ass is ted Hando f f

(MAHO)

• System instructs mobile to measure neighbor channels.

• Results reported back to system to aid handoff decision.

• Designed to decrease dropped calls and improve handoffs.

• TDMA supports any combination of handoff between digital

and analog channels.

• TDMA also supports handoff between 800 MHz and 1900MHz cellular bands.



The Dig ital

Contro l Channel

RACH SPACH BCCH SCF Reserved

PCH

ARCH

SMSCH

F - BCCH

E - BCCH

S - BCCH

Digital Control Channel

Reverse Channel (RDCCH)

Forward Channel (FDCCH)



Forward DCCH Slot Struc ture

• SCF (Coded Superframe Phase)

– Provides reverse DCCH access

control

• CSFP (Coded Superframe Phase)

– Provides superframe phase

• CDL (Coded Digital Locator)

– Provides DCCH .

• SYNC

– Provides for slot synchronization

• CDVCC

– Coded digital verification color

code

• DATA

– 1/2 convolutional coding with

intraslot interleaving

SYNC SCF DATA SCF RSVDDATACSFP

28 130 130 10 212 12

Forward DCCH

SYNC SACCH DATA RSVD CDLDATACDVCC

28 130 130 1 1112 12

Forward DTCH

Subf ields



Superframe Format ion

TimeSlot

1

TimeSlot

2

TimeSlot

3

TimeSlot

4

TimeSlot

5

TimeSlot

6

TimeSlot

1

TimeSlot

2

TimeSlot

3

TimeSlot

4

TimeSlot

5

TimeSlot

6

Superframe - 32 slots (0.64 sec duration)

TimeSlot

1

TDMA Frame

TDMA Block

SFP= 0

SFP= 1

SFP= 2

SFP= 3

SFP= 4

SFP= 5

SFP= 6

SFP= 7

SFP= 8

SFP= 9

SFP= 30

SFP= 31



Superframe Composi t ion

F-BCCH E-BCCH S-BCCH SPACH

F E S S... ... ...........

SFP 0 31

One Superframe = 16 TDMA frames = 640ms

... S

F-BCCH “Fast Broadcast

Channel” - Messages repeat every

superframe

- Messages contain

information critical for

service on DCCH

E-BCCH “Extended Broadcast Channel”

- Messages extended over multiplesuperframes

- Messages less time critical

S-BCCH “SMS Broadcast Channel” - Reserved for Broadcast SMS (IS-136B)

SPACH “SMS, Paging, and Access

Channel” - Used for sending Point-to-Point Messages

S




F E S S S... ... ...........

0 31

One Superfram e

... S


F E S S S... ... ...........

0 31

One Superframe

... S

One Hyperframe = Two Superframes = 1.28s

The SPACH “SMS, Paging, and Access Channel” - Page messages (PCH)

- PCH messages are always repeated in secondary superframe

- Access Response Messages (ARCH)

- ARCH messages are sent in idle SPACH slots (i.e. no page messages)

- ARCH message may be sent over multiple superframes

- Teleservices messages (SMSCH)

- SMSCH message are sent in idle SPACH slots

- SMSCH message may be sent over multiple superframes

Superframes

and Hyperframes



Sleepmode

• Sleepmode allows for battery savings

• Various level of sleepmode are supported

• Level of sleepmode is determined at registration

• Mobile assigned PCH slot is determined by hashing

algorithm

0 1 2 3 4 5 6

1 2 3 4 5 6 7 8Superframe

Hyperframe

Paging Frame

Class 1

Paging Frame

Class 3

Paging Frame

Class 2

9 10 11

12

13 14

Paging Frame Classes 4 through 8 not shown



(1) If mobile is unable to read PCH in primary superframe, it

must try reading assigned PCH in secondary superframe

(2) If the system changes F-BCCH, the mobile is notified through

system toggling of the BCN change flag in mobiles assigned

PCH slot.

(3) Changes in the E-BCCH are indicated by a change flag in the

F-BCCH.

Sleepmode Act iv i t ies

Primary Superframe Secondary Superframe

1

2

3

Next Hyperframe

F SPACH..F E.. E S..S F SPACH..F E..E S..S F..F E..E S..S



Reverse DCCH Slot Struc ture

6 6 16 28 122 24 122

G R PREAM SYNC SYNC+DATA DATA

Reverse DCCH

6 386 6 16 28 122 24 78

G R PREAM SYNC SYNC+DATA

Abbreviated Reverse DCCH

DATA R AG

6 6 16 28 122 12 12 122

G R DATA SYNC SACCH CDVCCDATA DATA

Reverse DTC

• Two burst lengths are defined to accommodate both large and small cells

• SYNC+ provides additional synchronization information to the base station.

• PREAM aids base station automatic gain control to reduce signal distortion.

• AG provides 38 bits of guard for the abbreviated burst.

• G and R provides guard and ramp.



R-DCCH Mult ip le Access

• Subchanneling allows for multiple uplink

paths

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3

time expended

Uplink RACH Subchannels

TDMA frame 40 ms

1 2 3 4 5 6 1 2

DCCH Downlink Bursts

4 5 6 1 2 3 4 5 6 1 2 3 4 5 6

Phone checks slot

availability

First burst

transmitted

Phones checks

reception status

Additional bursts

transmitted

1



Layer 3 - 2 - 1 Mapp ing

L3DATA

Layer 3 Message

L2 HDR CRC

L3

L2 L3DATA CRCL2 HDR

Sync DATA DATACSFP SCFL1



DCCH Layer 3

Funct ional i ty

• Call processing, registration, and

paging

• Mobile assisted channel allocation

(MACA)

• Identity structures

• Cell selection

• Cell reselection• Hierarchical cells

• Tiered services

– Private/public systems



Cal l Process ing

• Origination uses the same call model as IS-54B

– Phone sends origination message to system on reverse

DCCH

– Traffic channel designation sent in base stationresponse

• Paging on the DCCH

– A phone is allocated a particular SPACH slot which ismonitored for pages.

– This allocation is based on the MIN of the phone

• Authentication

– Same algorithms as used in IS-54B



Paging

• TDMA Paging – No rescan on reverse access channel removes the traditional

system border problems associated with analog.• Mobile responds to pages on the same DCCH as it receives pages on.

– Page message combination supports higher paging capacity• Single word paging uses one L2 frame per page

• Triple hard paging uses one L2 frame per three pages

• Standard allows for even further paging capacity through use of 20 and 24 bit

TMSIs

– TDMA registration techniques allow for defining precise paging

areas which can further increase messaging capacity.



Regis trat ion Types

• DCCH-based registration conditions are defined

according to the following order of priority:

– Test registration New to TDMA

– Power down

– Deregistration New to TDMA

– Power up

– System transition condition Enhanced in TDMA

– Location area (VMLA) New to TDMA

– Periodic registration Enhanced in TDMA

– ACC to DCCH transition New to TDMA

• The system broadcasts which forms of registration

are supported on F-BCCH.



VMLA Regis trat ion

110

10

10

5

10

10

4

5

8

4

5

8

4

4

4

8

9

9

8

9

9

9

9

51

1

RNUM broadcast by cell.

RNUM list sent to mobiles at registration.

Mobile must register when unknown RNUM received.



Aspects of TDMA Regis trat ion

• TDMA-Based Registration – Several new registration types are added in TDMA

– Mobiles indicate the registration type they are responding to.

– The nuisance registrations can be reduced

– The registration defined to fully support private, public, and

residential systems.

– VMLA-based registration • increases system control over paging load by tracking mobiles

based on location.

• eliminates the ping-pong registration problem by definingoverlapping areas.

Through a proper con f igurat ion, a TDMA sys tem can

result in reduced registrat ion traff ic with g reater paging

eff iciency.



Mobi le Ass isted Channel Al locat ion (MACA)

• MACA allows the mobile to provide the base station with

a channel quality report upon access.

• Channel Quality Report

– Long -term measurement - on serving DCCH: a running

average over 32 frames of RSS, WER, and BER.

– Short- term m easurement - on u p to 15 chann els specif ied by

base: RSS based on 4 measurements.

• The base station indicates the specific access types thatthe mobile is to provide a channel quality report.

• The MACA report can be used by the base station for

enhanced channel assignment.



DCCH Selection

• Digital control channels can be placed on anychannel within an operating band

• DCCH “pointers”

– Coded DCCH Locator (CDL):• The is sent within every forward digital traffic channel burst

• The CDL points to a location of a DCCH within a block channels.

– Control Channel Information Word (CCI):• The CCI word is sent as part of the ACCH overhead message.

• The CCI contains a pointer to a single DCCH, the pointer includes the

channel number, DVCC, and hyperband of a DCCH.

– DCCH pointers are provided upon call release

from both DTCs and AVCs.

– Probabilistic DCCH assignments may also be

used.



DCCH Select io n Process

• Exact DCCH selection procedures are

mobile vender specific.

Scan history channels forlast used DCCH

Scan analog control channelsfor DCCH pointer

Scan probability blocks for DCCHor DTC with locator field



Cell Reselect ion Procedu res

• TDMA cell reselection procedures areexecuted by mobiles while a mobile is in the

idle state (i.e., sleepmode).

• Parameters broadcast by the base stationgracefully steer mobiles to cells based on:

– Mobility

– Cell type (underlay or overlay)

– Relative and absolute RF thresholds

– Received signal strength

– Private, public, residential



DCCH Neighbo r L ists

• The DCCH neighbor list is central to the cell reselection process.

• Every DCCH broadcasts a neighbor list.

• The DCCH neighbor list provides mobiles with reselection

parameters on all neighbor cells and sectors. – Mobiles use this information to choose the appropriate cell based

mobility, desired network type, etc.

• The neighbor list provides the mobile with all neighbor parameters

needed for selection.

– There is no need for a mobile to sync up and read neighbor cells prior toreselection

• An additional neighbor list may also be broadcast for alternate

band (i.e. 800, or 1900MHz)



Signal Streng th Measurements

• While in the idle state, the mobile maintain two sets of signal

strength measurements.

• Long_RSS

– Long_RSS is a running average of 5 measurements maintained for the

serving DCCH in addition to all neighbor DCCHs.

• Short_RSS is a running average 2 RSSI measurements

– Short_RSS is a running average of 2 measurements maintained for the

serving DCCH only.

• Signal strength measurements are taken at a periodicity set

by the base station.

With TDMA, there’s no need to sync up and demodulate

neighbo r channels in order to take a pow er measurement.



The Neighbo r Lis t Message

This field provides neighbor DCCH specific informat ion as follows:

Fi el d Le ngth

CHAN 11

Protocol Version 4

DVCC 8

RESEL_OFFSET 7

SS_SUFF 5

DELAY 4

HL_FREQ 1

CELL_SYNC 1

CELLTYPE 2

Network Type 3

Direct ed Retry Channel 1

MS_ACC_P WR 4

RSS_ACC_MIN 5

PSID/RSID Indicator 1

PSID/RSID Support Length 0 or 4

PSID/RSID Support (Note1) 0 or 1 - 16

Neighbor Cell 1

Neighbor Cell 2

Neighbor Cell 3

Neighbor Cell 24

Neighbor List Message



Key Reselect ion Parameters

• RSS_ACC_MIN

– Minimum signal strength required for a phone to access a cell.

• RESEL_OFFSET

– A hysteresis value used for adjacent cell reselection (i.e. celltype regular).

• SS_SUFF

– The signal strength deemed sufficient for a phone to reselecta preferred or regular cell.

• MS_ACC_PWR

– Maximum power a phone can use to access a particular cell.



Reselect ion Parameters ,

Cont .

• Delay

– Specifies the minimum time for which a

candidate cell must be seen at adequatesignal

• CELLTYPE

• Specifies a



Cell Reselect ion -

Adjacent Cel ls

Example – Adjacent Cells

Suggested Sett ings :

CELLTYPEB = REGULAR

DELAYB = 0

RESEL_OFFSETB = -3dB

Cell BoundaryAB

Macrocell (regular)

A

Macrocell (regular)

B

(RESEL_OFFSETB)+ (RESEL_OFFSETB)-

RESEL_OFFSET provides hysteresis between two adjacent cells



Cell Reselec tion - Delay

NL Delay – Microcells

mobile direction

RSS_ACC_MIN

DELAYm

C D

Macrocell (overlay)

Microcell

A

B


CELLTYPEB = Preferred

DELAYB = 1 or more hyperframes;

Delay should be set high enough

to keep high mobility mobiles off

microcell



Reselec tion - Underlay

SS_SUFF

Example – Underlaid

Microcell

Assumpt ions :

Handoff BA = -85

dBm


CELLTYPEB =

PREFERRED

SS_SUFFB = -82 dB

DELAYB = 1 or higher

-82 d Bm

Macrocell (non-preferred)

Microcell (preferred)

A

B

-72 d Bm

SS_SUFFB



Total Sys tem In tegrat ion

Cell Reselection

Private/PublicSystems

HierarchicalCells

TDMA

Flexibi l i ty



Hierarch ical Cells

• Hierarchical cell structures – Low power microcells overlaid by high power macrocells

• Why hierarchical cells ?

– Flexible system growth/ increased capacity

• Low mobility traffic

• In building

• Hot spots/ cold stops

– Tiered services

• Private and residential systems – Capacity when and where you need it.

– Extended mobile talk time

With TDMA, there’s no cumbersome power control issues

involved in set t ing up low pow er under layed cel ls .

A C it T l



Capacity:Cell SplitAlternative

Cold Spot:Fill-in

A Capaci ty Too l -

Hierarch ical Cells

Due to h ierarchical deploym ent, TDMA offers

the best long -term RF capacity story

Capacity:Traffic Relief

Cold Spot:EconomicRemoteCoverage

Capacity:

In BuildingApplication



Tiered Serv ices

Public

Residential

Workplace

Mall/ Airport, etc.



Types o f Private Systems

• Virtual private systems

– Semi-private systems

• Airport, mall, convention center

– Private only systems• Office parks

– Residential systems

• Neighborhoods, suburbs

• Autonomous systems – Wireless PBX

• Companion microcellResidential

Tiered

ServiceRegions

WPBX

Public



Basic Capab i l i t ies

• Capabilities provided through TDMA

include:

– Seamless system transition between private and

public systems

– Differentiated charging

– Alphanumeric display of serving system

– Underlays and in building support

– Private only or semi-private

– Possible to define multiple private systems off a

single DCCH

Due to TDMA cel l reselect ion and h ierarchical deployment,

TDMA offers stro ngest t iered services s tory.



The Mechanics of Tiered Services

• Cell Reselection Algorithms: – Seamless DCCH transition between public and private systems.

• Registration Procedures: – Assign and remove subscribers from system

– Remove risk of nuisance registrations.

• System Identities: – Private and residential system IDs uniquely identify a system

– Network type (3 bit map on the DCCH) defines a cell as public,

private, residential, or semiprivate.

• Alpha Tags: – Identify systems to subscribers by alphanumeric name.

• System Priorities:

– Users rank private, residential, or public systems according toreference.



TDMA - Dig ital PCS

TDMA Scorecard

Dual-Band Standard ¦ PCS at 800 & 1900 MHz

Terminals ¦ Dual-band, cost effective

Voice Quality ¦ EFRC MOS - wireline equivalent

Capacity ¦ N=5/4 reuse and underlays

Enhanced Services ¦ SMS, Over-the-Air Activation,

Sleepmode, IS-41C, ...

In-building Services ¦ Hierarchical cell structure

for underlays and WPBX

Data ¦ Circuit switched using IS-135

High speed data evolution path

Roaming ¦ 1900 / 800MHz TDMA & AMPS

Intelligent directed roaming

S i d D i



Services and Design

Examples

• Short message service features and

examples

• Over-the-air activation

• Wireless office design example

• Circuit switched data service

• TDMA summary



Cellular Messag ing

• Enables alphanumeric messages to be exchanged between the

network and a DCCH capable phone.

• Message delivery is acknowledged.

• Message attributes dictate phone behavior.

• Includes two way messaging and in-call delivery.

base station

meeting isLarry: the

canceled

Larry: the

meeting is

canceledmessage

TNPPTAP

Voice

IS-41

. . . . . .. . . . . .. . . . . ...

MSC

e-mail

center

meeting is

canceled

Larry: the

. . . . . .

Larry: the

meeting is

canceled



Messaging Examples

• One-way information services – News, stock quotes, sports scores.

– Broadcast services • Traffic, weather, etc.

• E-mail notifications – Containing “from,” “subject” and first part of message.

• Paging – Both one- and two-way paging with responses and

acknowledgments.

• Platform for integrated messaging solutions

– Voice mail, etc.



On-A ir Act ivat ion

• Enables delivery of NAM information and

updates to the phone over the air.

• Simplifies the activation process for both

the subscriber and service provider.• Provides a flexible download capability.

• Provides a secure mechanism for A-key

updates.



WOS Design Example

• RF planning

• Hierarchical cell structure design

• System identities• Registration

• Phone programming

Wh Use a Hierarch ical Cel l



Why Use a Hierarch ical Cel l

Structu re ?

• To bias the weaker cell

• Ease of design

Macrocell

Base station

Macrocell

Base station

Microcell

Microcell

HCS in an Indoo r/Outdoo r



HCS in an Indoo r/Outdoo r

Site

Macrocell

Base Station

Microcell

Microcell

R

P

NP

R

NP

P

P

NP

RR

P

NP

Macrocell

Base Station



WOS Cel l Con f igu rat ion

macrocell 1

SS_SUFF

select macrocell 1

Neighbor cell relationships : R = Regular, P = Preferred, NP = Non-Preferred,

SS_SUFF = Signal strength sufficient parameter

select office microcell select macrocell 2

macrocell 2

R

R

P

NP NP

P



Sys tem Ident i t ies

• Each cell can broadcast the following system

identities

– SID - same as today’s SID.

– SOC - system operator code indicating the cellular systemoperator.

– PSID - private system identities used to distinguish private or WOS

systems.

• Network types can be assigned to each sector for

service differentiation

– Public

– Private

– Residential

– Or mixture (public and private, public and residential, etc.)



PSID Values

PSID Value (hex) Range and Function Use Match dependenton

0000 Unused

0001-2FFF SID-specific PSIDs WOS customers in single PSID, SIDSID area

3000-CFFF SOC-specific PSIDs WOS National accounts PSID, SOC

D000-DFFF Nationwide PSIDs Inter-carrier accounts PSID, MCC

E000-EFFF International PSIDs International accounts PSID

F000-FFFF Reserved



SID and PSID Regis trat ion

SID = 47

SID = 33

SID = 33, PSID = 1000

REG

REG

REG

REG

REG

REG

SID Change Registration

PSID Change Registration

(when phone enters cell withdifferent PSID status)

REG

REG

REGREG

SID = 33, PSID = 1000

SID Border



PSIDs and Locat ion ID

Broadcast Parameters

SID = 47

SOC = 801

PSID1 = 1228

PSID2 = 5760

PSID3 = 2151PSID5 = 11127

Enterprises AOB

AssociatesHawthorn

Wireless AT&T

MemorialGillarde

Hospital

Hawthorn

Associates

Gillarde

Memorial

Hospital

AT&T

Wireless

AOB

Enterprises

Inc

Inc.



Phone and Sys tem Conf igu ration

for Locat ion ID

• System broadcasts SID, SOC and PSID.

• Phone is preprogrammed with SID, SOC and PSID parameters

along with Alphatag

– Alphatag is a system banner that the customer wants on the display of

the phone. – Programming can be performed over the air.

• Depending on PSID type, phone will recognize WOS system

using combination of SID, SOC and PSID.

• When phone enters WOS system, it will register when an identitymatch is made and will display the company banner or Alphatag.

• Phone will re-register upon leaving private system.



TDMA Data Serv ices

• TDMA introduces a digital circuit-switched

service for session- based transactions

like fax and dial-up network access.

• Compare to packet data for short sporadic

transactions.

Circui t Switched and Packet



Circui t -Switched and Packet

Data

• Circuit-Switched Data – Transactions rely on a call being established.

– Channel and resources are occupied by a single user.

– Efficient for fax, file transfers and where data is being

exchanged for a high proportion of the connect time.

• Packet Data

– “Connectionless” service (no call setup overhead).

– Many users share the same radio channel. – Efficient for short, bursty, sporadic transactions (like e-mail, web

browsing or virtual connections).

T t C t f Ci i t



Transport Concept for Circui t -

Switched Data

MSC



Layered Data Model

40 ms

IS-135

IS-130 IS-130

Digital Traffic Channel

TDMA frames

AT Commands and

User Data

Radio Link Protocol 1

Data Data DataData



Data Standards

• IS-130 - Radio Link Protocol

– Error control

– Compression

– Encryption

• IS-135 - Async Data and Fax

– Data call setup, supervision, and clearing

– AT-command handling

– Signal leads



TDMA - A ir In terface

• TDMA Air Interface 800 and 1900 MHz

• Digital Control Channel – Same call control, reselection, HCS, roaming and private

system features.

• Digital Traffic Channel – Re-programmed for data or voice on a per call basis.

• Same Registration, Authentication and Handoff.



26

Radio Resources

• Uses same Digital Traffic Channel resources

– Trunking efficiency

– Configurable per call

– Controlled by switch – Optimization and O&M the same as traffic

channels.



TDMA Features

• Perfect faxes delivered real-time at about two pagesper minute.

• File transfers could be up to 115,200 bit/s with triple

rate channel and compression (depending on data) – Full Rate - 9.6 kbit/s uncompressed - 38.4 kbit/s compressed

• Detects and correct errors, compresses and encrypts

data.

• No special modem or fax machine required on

wireline side.

• Phone looks like a wireline fax/data modem.

• Compatible with existing software.

– Future Windows unimodem will also contain built in support.



Throughput of Data Service

Throughput

(bits/s)

*Depending on data and channel conditions

DTCCompression

off

Compressionon

Full Rate 9,600 19,200 to

38,400

TripleRate

28,800 57,000 to115,200*



Futu re Data Act iv i t ies

• Multi-slot Operation

– Concatenate timeslots to give higher throughput.

• Direct IP Connectivity.

• Browser Activity Increasing in TDMA Arena.

• Packet Data Transport in TDMA Environment

– Standard in development

– Provides integrated packet data solution for TDMA.



Futu re TDMA Features

• Broadcast Short Message Service

• Enhanced Talk Time

– Discontinuous mode (DTX) with comfort noise doubles talk

time

• Integrated TDMA Packet Data Solution

• Teleservice Transport Enhancements

– Segmentation

– Assignment to traffic channel for long messages



TDMA Benefi ts

• The DCCH is a method for rapid deployment of

advanced services based on existing AMPs

infrastructure.

• The DCCH is the platform for seamless 800 MHz

and 1900 MHz PCS implementation.

• The DCCH offers new features to our customers.



TDMA Benef i ts - cont .

• Cost – TDMA can coexist with existing AMPS radios and frequencies.

– Digital capability can be introduced when and where it’s needed.

– AMPs equipment can be selectively upgraded or redeployed.

• Capacity – TDMA introduces at least a threefold increase over AMPS capacity

• Even greater with use of Hierarchical Cell Structures, Adaptive

Channel Allocation etc.

• Voice Quality – ACELP vocoder significantly improves voice quality.

• Roaming – Dual mode handsets and AMPS/TDMA compatibility ensures

ubiquitous network access.



TDMA Summary

• Enhanced Services Sleep mode

Voice privacy

Authentication

Message waiting indicator Calling number identification

Circuit switched data

Short message service

Private system features Hierarchical Cell Structures

800 and 1900 MHz Operation

On air activation

Documents

6534Tdma Tutorial[1]