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Overview of 3G Packet
Data
Salih Ergut
7/16/2003
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Outline
cdma2000 packet data
architecture and network elements
Simple IP/Mobile IP
Packet Network Nodes State Machines
MAC Layer
Packet Data Call Flows
1x EV-DV (1xRTT Evolution for high-speedintegrated Data and Voice)
Motivation, goals and basic principles
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Packet Data Architecture
BSC
MSC PSTNVLR
HLR
PCF PDSN
AAA
Packet
Network
Telephone
Network
Home
Agent
Home
AAA
SS7
Network
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Simple IP vs. Mobile IP
Mobile stations IP address will be changed
as the subscriber moves to different cells
Mobile station will be able to use a constant
IP even when moving across different cells
BSC PCF PDSNPacket
Network
BSC
PCF
PDSN
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Mobile IP Registration
Mobile registersits care ofaddress
HA replies withlifetime
PDSN
(FA)
Packet
Network Home AgentBSS
MIP-RRQ
MIP-RRQ
MIP-RRP
MIP-RRP
Packet Data Tunnel (UDP over IP)
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Packet Network Nodes
PCF (Packet Control Function)
A required IP element in cdma2000 networks
Provides relay to mobile from PDSN
Keeps track of registration lifetime expiration and ensuresthat the sessions are renewed as necessary
Controls the available radio resources Buffers data received from PDSN until radio resources
becomes available
Controls dormancy
PDSN (Packet Data Serving Node)
PPP datalink layer to mobile is terminated
Interfaces with PCF
IP packets are routed
In MIP network acts as a FA
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Packet Network Nodes
AAA (Authentication, Authorization, andAccounting)
Stores accounting information andauthenticates/authorizes mobiles
Provides security to FA and Foreign AAA.
HA (Home Agent)
Establishes a secure packet-data tunnel with
the FA to provide MIP services and routes thepackets destined to the mobile to the FA
Authenticates MIP registrations
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Assign Complete
Mobile Originated Packet Data Call
MSCPDSNBSC / PCF
Origination
Base Station AckCMServReq
SCCP-CC
Assign RequestTCH Setup
A11-RRQ
A11-RRP
User Packet Data
PPP Link Establishment and Mobile IP Registration
A8 /A10
setup
Packet
Network
UCSD Ericsson ///
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Control PlaneSignaling
BSC/PCF PDSN
A11
UDP
IP
Link
Phys
A11
UDP
IP
Link
Phys
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User PlaneRelay Mode
BSC/PCF PDSN
RS-23
2
RLPRS-23
2
GRE
AIRInter-
face
RLP
AIRInter-
face
IP
Link
Phys
End
Host
IP
PPP
A10
IP
PPP
IP
Link
Phys
IP
Link
Phys
GRE
IP
Link
Phys
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User PlaneNetwork Mode
BSC/PCF PDSN
RS-23
2
RLPRS-23
2
GRE
AIRInter-
face
RLP
AIRInter-
face
IP
Link
Phys
End
Host
IP
SLIP or
PPP
A10
IP
PPP
IP
Link
Phys
IP
Link
Phys
GRE
IP
Link
Phys
SLIP or
PPP
IP
PPP
IP
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MAC States (1/3)
Active Mode and DTX
Data traffic flows
Reverse pilot is not gated
MS and BS can discontinue traffic for 10-20frames (~200ms) without tearing down trafficchannel
Control/Hold Dormant
second minute
Active
FCH
Active
SCH
millisecond
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MAC States (2/3)
Control Hold
Triggered when the data traffic is idle ~1-2 seconds
Signaling only
Power control is maintained
Reverse pilot can be gated
MS Stores radio information
Control/Hold Dormant
second minute
Active
FCH
Active
SCH
millisecond
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MAC States (3/3)
Dormancy
Triggered when data traffic is idle ~1-2 minutes
Traffic channels and A8 (BSC-PCF) connection is
released
A10 (PCF-PDSN) connection and PPP is maintained
Control/Hold Dormant
second minute
Active
FCH
Active
SCH
millisecond
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Dormant Mode
Initiation
BSC initiates when inactivity timer is expired or RF failure
occurred
MS initiates when inactivity timer is expired or TCH is
released
Reactivation
Initiated when network or MS has data to send
Since PPP is maintained no extra control plane signaling
required
User data is exchanged after reactivation
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Inter BSCIntra PDSN HHO
MSC PDSNSourceBSC/PCF
HO Required
HO Command
User Packet Data
HO Request
HO Request ACK
HO Commenced
TargetBSC/PCF
HO Direction Msg
Null Fwd Traffic
Rev Traffic
HCMTear Down Channels
Clear Command
Clear Complete
A11 RRQ (Lifetime = 0)
A11 RRP
A11 RRQ
A11 RRP
Handoff Complete
User Packet Data
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Quality of Service
Still standardization is continuing
Air interface is bottleneck for an end-to-end
QoS
Some parameters are defined such as
Users priority level (14 possible levels)
Minimum acceptable data rate (2x, 4x, )
Acceptable FER (1%, 2%, 5%, 10%)
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1x EV-DV
(1xRTT Evolution for
high-speed integrated
Data and Voice)
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Motivation
CDMA 1x supplemental channel scheduling
is slow (~2-4 secs) and data rate is not
satisfactory (~144 kbps)
Forward link has priority due to asymmetricnature of the data applications
Flexibility against short term and long term
voice and data demands
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Design Goals
Backward compatibility with cdma2000 1x
cdma2000 1x features, applications and
services and voice/data capabilities are
maintained Minimal effect on the terminals and
infrastructure for cdma2000 1x customers
increase battery life as a side goal
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Design Requirements
FL peak data rate > 2.4 Mbps
RL peak data rate > 1.25 Mbps
Average throughput in FL and RL > 600 kbps
Peak data rate and average throughput is at
least as much as 1X EV-DO
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Whats needed?
Radio resources should be optimally used
Radio link control & resource allocation must
be optimized
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How is it achieved? (1/3)
1x overhead
Residual power for 1x EV-DV
1xEV-DVoverhead
Power for 1x voice and data
BaseStationPower
100%
Time
Packet Data Common Channel is introduced
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How is it achieved? (2/3)
Left-over power is used, hence no power
control
Rate control (higher order modulation and
coding) is used to maintained link quality Optimally schedule delay tolerant data
Favor the user with good channel quality
Serve users both in parallel (CDM) and serial
(TDM) while TDM is preferred if possible
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How is it achieved? (3/3)
Fast sector switching
Fast channel quality indicator send by MS
Fast physical layer ARQ (Automatic Repeat
Request) which also provides error correction
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Whats next?
Reverse link data enhancements are
necessary to meet the requirements, i.e. 1.25
Mbps
Common services and mobility with differenttype of network access technologies, such as
Wireless LANs, DSL, satellites etc.
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4G
Higher data rates ~2-20 Mbps
New air interface needs to be developed
Potential candidate OFDM
Smart antennas can form directed beams toincrease strength of the desired signal
A new spectrum needs to be assigned
Software radio can transmit over different air
interface technologiesAll-IP vision: base stations become an access
router
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