Transcript TDMA Tutorial - Network, Telecom & Wireless Technology Courses

TDMA
Tutorial
Outline of Presentation
• 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, message
waiting 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 Evolution
Services
Quality
Capacity
Coverage
Cost
TDMA B
TDMA A plus
EFRC
IS-54 Adopted
by TIA/CTIA
TDMA in Commercial Service
TDMA Standards
Process Begins
1988
1990
TDMA Rev. 0
1992
1994
1996
1998
TDMA Traffic Channel Structure
40 ms
TDMA Frame
Sync
SACCH
Data
CDVCC
Data
RSVD
TDMA Slot Format
• 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 Speech Coding
• 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 Coding
96
Class-1 bits
7
Rate 1/2
Convolutional
Coding
216
Coded
Class-1
bits
208
Voice Cipher
7-bit CRC
Computation
Puncturing
Speech Coder (ACELP)
48 Most
Perceptually
Significant
Bits
260
2-slot interleaver
5 Tail bits
52
Class-2 bits
codec + channel coding =
7.4kbps + 5.6kbps = 13kbps
codec 7.4kbps
speech
fr ames
x and y
speech
fr ames
y and z
40 msec
260
Test Condition
13 dB 60 mph
13 dB 30 mph
13 dB 5 mph
15 dB 60 mph
15 dB 30 mph
15 dB 5 mph
17 dB 60 mph
17 dB 30 mph
17 dB 5 mph
Clean
MOS
TDMA Voice Quality
EFRC vs. VSELP
4.50
4.00
3.50
3.00
2.50
EFRC
2.00
VSELP
1.50
1.00
0.50
0.00
Mobile Assisted Handoff
(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 1900
MHz cellular bands.
The Digital
Control Channel
Digital Control Channel
Forward Channel (FDCCH)
Reverse Channel (RDCCH)
RACH
SPACH
BCCH SCF
PCH
F - BCCH
ARCH
E - BCCH
SMSCH
S - BCCH
Reserved
Forward DCCH Slot Structure
Forward DCCH
SYNC
SCF
DATA
CSFP
DATA
28
12
130
12
130
10
DATA
CDVCC
DATA
RSVD
CDL
130
12
130
1
11
SCF
RSVD
2
Forward DTCH
SYNC SACCH
28
12
Subfields
•
•
•
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
Superframe Formation
TDMA Frame
TDMA Block
Time
Slot
1
Time
Slot
2
Time
Slot
3
Time
Slot
4
Time
Slot
5
Time
Slot
6
Time
Slot
1
Time
Slot
2
Time
Slot
3
Time
Slot
4
SFP
=0
SFP
=1
SFP
=2
SFP
=3
SFP
=4
SFP
=5
SFP
=6
SFP
=7
SFP
=8
SFP
=9
Superframe - 32 slots (0.64 sec duration)
Time
Slot
5
Time
Slot
6
Time
Slot
1
SFP
= 30
SFP
= 31
Superframe Composition
One Superframe = 16 TDMA frames = 640ms
SPACH
F-BCCH E-BCCH S-BCCH
F
SFP
...
E
...
S
...
S
S
0
F-BCCH “Fast Broadcast
Channel”
- Messages repeat every
superframe
- Messages contain
information critical for
service on DCCH
S-BCCH “SMS Broadcast Channel”
- Reserved for Broadcast SMS (IS-136B)
...........
S
31
E-BCCH “Extended Broadcast Channel”
- Messages extended over multiple
superframes
- Messages less time critical
SPACH “SMS, Paging, and Access
Channel”
- Used for sending Point-to-Point Messages
Superframes
and Hyperframes
One Hyperframe = Two Superframes = 1.28s
One Superframe
SPACH
F-BCCH E-BCCH S-BCCH
F
0
...
E
...
S
...
One Superframe
S
S
...........
SPACH
F-BCCH E-BCCH S-BCCH
S
F
...
E
...
S
...
S
S
...........
31 0
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
S
31
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
Superframe
Hyperframe
1
2
0
3
4
1
5
6
2
7
8
3
9 10 11
4
5
Paging Frame
Class 1
Paging Frame
Class 2
Paging Frame
Class 3
Paging Frame Classes 4 through 8 not shown
13 14
126
Sleepmode Activities
Primary Superframe
Secondary Superframe
Next Hyperframe
F..F E.. E S.. S
SPACH
F..F E.. E S.. S
F..F E.. E S.. S
SPACH
3
1
2
(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.
Reverse DCCH Slot Structure
Reverse DCCH
G R PREAM
6
6
16
SYNC
28
DATA
122
SYNC+
DATA
24
122
Abbreviated Reverse DCCH
G R PREAM
6
6
16
SYNC
28
DATA
122
SYNC+
DATA
R
AG
24
78
6
38
Reverse DTC
G R
6
6
DATA
SYNC
16
28
DATA
122
SACCH CDVCC
12
12
DATA
122
• 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 Multiple Access
• Subchanneling allows for multiple uplink
paths
TDMA frame 40 ms
1
2
3
4
5
6
1
2
DCCH Downlink Bursts
1
2
3
4
5
6
1
Phone checks slot
availability
2
3
4
5
6
1
2
3
1
2
3
5
6
Additional bursts
transmitted
4
5
6
1
2
Uplink RACH Subchannels
time expended
6
Phones checks
reception status
First burst
transmitted
4
5
3
4
1
Layer 3 - 2 - 1 Mapping
L3
Layer 3 Message
L2
L2 HDR
L1
Sync
L3DATA
DATA
CRC
L2 HDR
CSFP
L3DATA
DATA
CRC
SCF
DCCH Layer 3
Functionality
• Call processing, registration, and
paging
• Mobile assisted channel allocation
(MACA)
• Identity structures
• Cell selection
• Cell reselection
• Hierarchical cells
• Tiered services
– Private/public systems
Call Processing
• Origination uses the same call model as IS54B
– Phone sends origination message to system on reverse
DCCH
– Traffic channel designation sent in base station
response
• Paging on the DCCH
– A phone is allocated a particular SPACH slot which is
monitored 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.
Registration Types
• DCCH-based registration conditions are defined
according to the following order of priority:
–
–
–
–
–
–
–
–
Test registration
Power down
Deregistration
Power up
System transition condition
Location area (VMLA)
Periodic registration
ACC to DCCH transition
New to TDMA
New to TDMA
Enhanced in TDMA
New to TDMA
Enhanced in TDMA
New to TDMA
• The system broadcasts which forms of registration
are supported on F-BCCH.
VMLA Registration
1
5
10
1
4
5
10
4
1
4
10
9
9
4
5
8
10
9
4
5
10
9
9
9
8
8
8
RNUM broadcast by cell.
RNUM list sent to mobiles at registration.
Mobile must register when unknown RNUM received.
Aspects of TDMA Registration
• 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 defining
overlapping areas.
Through a proper configuration, a TDMA system can
result in reduced registration traffic with greater paging
efficiency.
Mobile Assisted Channel Allocation (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 measurement - on up to 15 channels specified by
base: RSS based on 4 measurements.
• The base station indicates the specific access types that
the 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 any
channel 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 Selection Process
• Exact DCCH selection procedures are
mobile vender specific.
Scan history channels for
last used DCCH
Scan analog control channels
for DCCH pointer
Scan probability blocks for DCCH
or DTC with locator field
Cell Reselection Procedures
• TDMA cell reselection procedures are
executed by mobiles while a mobile is in the
idle state (i.e., sleepmode).
• Parameters broadcast by the base station
gracefully steer mobiles to cells based on:
–
–
–
–
–
Mobility
Cell type (underlay or overlay)
Relative and absolute RF thresholds
Received signal strength
Private, public, residential
DCCH Neighbor Lists
• 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 to
reselection
• An additional neighbor list may also be broadcast for alternate
band (i.e. 800, or 1900MHz)
Signal Strength 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
neighbor channels in order to take a power measurement.
The Neighbor List Message
Neighbor List Message
Thi s field provi des nei ghbor DCCH specific information as fol lows:
Field
Length
CHAN
11
P rotocol Version
4
Neighbor Cell 1
DVCC
8
Neighbor Cell 2
RESEL_OFFSET
7
SS_SUFF
5
Neighbor Cell 3
DELAY
4
HL_FREQ
1
CELL_SYNC
1
CELLTYP E
2
Net work Type
3
Directed Retry Channel
1
MS_ACC_PW R
4
RSS_ACC_MIN
5
P SID/RSID Indicator
1
Neighbor Cell 24
P SID/RSID Support Lengt h
0 or 4
P SID/RSID Support (Note1)
0 or 1 - 16
Key Reselection Parameters
•
RSS_ACC_MIN
–
•
RESEL_OFFSET
–
•
A hysteresis value used for adjacent cell reselection (i.e. cell
type regular).
SS_SUFF
–
•
Minimum signal strength required for a phone to access a cell.
The signal strength deemed sufficient for a phone to reselect
a preferred or regular cell.
MS_ACC_PWR
–
Maximum power a phone can use to access a particular cell.
Reselection Parameters,
Cont.
• Delay
– Specifies the minimum time for which a
candidate cell must be seen at adequate
signal
• CELLTYPE
• Specifies a
Cell Reselection Adjacent Cells
Example – Adjacent Cells
Macrocell (regular)
A
Macrocell (regular)
B
Suggested Settings:
CELLTYPEB = REGULAR
DELAYB = 0
RESEL_OFFSETB = -3dB
+
(RESEL_OFFSET B)
(RESEL_OFFSET B)
Cell BoundaryAB
RESEL_OFFSET provides hysteresis between two adjacent cells
-
Cell Reselection - Delay
NL Delay – Microcells
A
Macrocell (overlay)
B
mobile direction
Microcell
RSS_ACC_MIN
DELAY m
Suggested Settings:
C
CELLTYPEB = Preferred
DELAYB = 1 or more hyperframes;
D
Delay should be set high enough
to keep high mobility mobiles off
microcell
Reselection - Underlay
SS_SUFF
Example – Underlaid
Microcell
Macrocell (non-preferred)
A
Microcell (preferred)
B
Assumptions:
HandoffBA = -85
dBm
-72 dBm
SS_SUFFB
Suggested Settings:
CELLTYPEB =
PREFERRED
SS_SUFFB = -82 dB
DELAYB = 1 or higher
-82 dBm
Total System Integration
Cell Reselection
TDMA
Private/Public
Systems
Flexibility
Hierarchical
Cells
Hierarchical 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 setting up low power underlayed cells.
A Capacity Tool Hierarchical Cells
Cold Spot:
Fill-in
Cold Spot:
Economic
Remote
Coverage
Capacity:
Cell Split
Alternative
Capacity:
Traffic Relief
Due to hierarchical deployment, TDMA offers
the best long-term RF capacity story
Capacity:
In Building
Application
Tiered Services
Workplace
Public
Residential
Mall/ Airport, etc.
Types of Private Systems
• Virtual private systems
– Semi-private systems
• Airport, mall, convention center
– Private only systems
Public
• Office parks
– Residential systems
• Neighborhoods, suburbs
Tiered
Service
Regions
• Autonomous systems
– Wireless PBX
• Companion microcell
Residential
WPBX
Basic Capabilities
• 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 cell reselection and hierarchical deployment,
TDMA offers strongest tiered services story.
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 to
preference.
TDMA - Digital PCS
TDMA Scorecard
Dual-Band Standard
Terminals
Voice Quality
Capacity
Enhanced Services
¦
¦
¦
¦
¦
In-building Services
¦
Data
¦
Roaming
¦
Fixed & Mixed
¦
PCS at 800 & 1900 MHz
Dual-band, cost effective
EFRC MOS - wireline equivalent
N=5/4 reuse and underlays
SMS, Over-the-Air Activation,
Sleepmode, IS-41C, ...
Hierarchical cell structure
for underlays and WPBX
Circuit switched using IS-135
High speed data evolution path
1900 / 800MHz TDMA & AMPS
Intelligent directed roaming
Mobility, fixed, & mixed
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 Messaging
• 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.
Larry: the
meeting is
canceled
e-mail
Larry: the
meeting is
canceled
Larry: the
meeting is
canceled
......
. .. .. .. .. .. .. ...
TNPP
TAP
message center
Larry: the
meeting is
canceled
IS-41
base station
Voice
MSC
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-Air Activation
• 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
Why Use a Hierarchical Cell
Structure ?
Microcell
Macrocell
Base station
Microcell
Macrocell
Base station
•
•
To bias the weaker cell
Ease of design
HCS in an Indoor/Outdoor
Site
R
R
NP
Microcell
NP
P
P
NP
P
P
NP
Macrocell
Base Station
Microcell
R
R
Macrocell
Base Station
WOS Cell Configuration
R
R
macrocell 1
P
NP
macrocell 2
P
NP
SS_SUFF
select macrocell 1
select office microcell
Neighbor cell relationships :
R = Regular, P = Preferred,
NP = Non-Preferred,
SS_SUFF = Signal strength sufficient parameter
select macrocell 2
System Identities
• Each cell can broadcast the following system
identities
– SID - same as today’s SID.
– SOC - system operator code indicating the cellular system
operator.
– 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 dependent
on
0000
Unused
0001-2FFF
SID-specific PSIDs
WOS customers in single
SID area
PSID, SID
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 Registration
SID Border
SID = 47
SID = 33
SID = 33, PSID = 1000
REG
REG
REG
REG
REG
SID Change Registration
REG
REG
PSID Change Registration
REG
(when phone enters cell with
different PSID status)
REG
REG
SID = 33, PSID = 1000
PSIDs and Location ID
AOB
Enterprises
Inc
Gillarde
Memorial
Hospital
Gillarde
Memorial
Hospital
AOB
Enterprises
Inc.
Broadcast Parameters
Hawthorn
Associates
AT&T
Wireless
Hawthorn
Associates
AT&T
Wireless
SID = 47
SOC = 801
PSID1 = 1228
PSID2 = 5760
PSID3 = 2151
PSID5 = 11127
Phone and System Configuration
for Location 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 identity
match is made and will display the company banner or Alphatag.
•
Phone will re-register upon leaving private system.
TDMA Data Services
• 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.
Circuit-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).
Transport Concept for CircuitSwitched Data
MSC
Layered Data Model
AT Commands and
User Data
IS-135
IS-130
Data
Data
Data
IS-130
Radio Link Protocol 1
Data
Digital Traffic Channel
TDMA frames
40 ms
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 - Air Interface
• 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.
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.
26
TDMA Features
• Perfect faxes delivered real-time at about two pages
per 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)
DTC
Full Rate
Triple
Rate
Compression
off
Compression
on
9,600
19,200 to
38,400
28,800
57,000 to
115,200*
*Depending on data and channel conditions
Future Data Activities
• 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.
Future 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 Benefits
• 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 Benefits - 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.