Transcript Overview of 3G Packet Data

Overview of 3G Packet
Data
Salih Ergut
7/16/2003
1
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-speed
integrated Data and Voice)

Motivation, goals and basic principles
2
Packet Data Architecture
SS7
Network
VLR
HLR
MSC
Telephone
Network
PSTN
AAA
BSC
PCF
PDSN
Packet
Network
Home
Agent
Home
AAA
3
Simple IP vs. Mobile IP
 Mobile station’s 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
PDSN
Packet
Network
PDSN
PCF
BSC
4
Mobile IP Registration
BSS
PDSN
(FA)
Packet
Network
MIP-RRQ
MIP-RRQ
MIP-RRP
MIP-RRP
Packet Data Tunnel (UDP over IP)
Home Agent
Mobile registers
its care of
address
HA replies with
lifetime
5
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 ensures
that 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

6
Packet Network Nodes
 AAA (Authentication, Authorization, and
Accounting)


Stores accounting information and
authenticates/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 the
packets destined to the mobile to the FA
 Authenticates MIP registrations
7
Mobile Originated Packet Data Call
Ericsson ///
UCSD
MSC
BSC / PCF
PDSN
Origination
Base Station Ack
CMServReq
SCCP-CC
TCH Setup
Assign Request
A11-RRQ
A11-RRP
A8 /A10
setup
Assign Complete
PPP Link Establishment and Mobile IP Registration
User Packet Data
Packet
Network
8
Control Plane – Signaling
A11
A11
UDP
UDP
IP
IP
Link
Link
Phys
Phys
BSC/PCF
PDSN
9
User Plane – Relay Mode
IP
IP
PPP
PPP
RS-232
RS-232
RLP
AIR
Interface
GRE
GRE
IP
IP
RLP
AIR Link
Interface Phys
IP
IP
Link
Link
Phys
Phys
Link
Phys
BSC/PCF
PDSN
A10
End
Host
10
User Plane – Network Mode
IP
IP
IP
IP
SLIP or
PPP
SLIP or
PPP
PPP
PPP
RS-232
RS-232
RLP
AIR
Interface
GRE
GRE
IP
IP
RLP
AIR Link
Interface Phys
IP
IP
Link
Link
Phys
Phys
Link
Phys
BSC/PCF
PDSN
A10
End
Host
11
MAC States (1/3)
 Active Mode and DTX
 Data traffic flows
 Reverse pilot is not gated
 MS and BS can discontinue traffic for 10-20
frames (~200ms) without tearing down traffic
channel
Active
SCH
millisecond
Active
FCH
Control/Hold
second
Dormant
minute
12
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
Active
SCH
millisecond
Active
FCH
Control/Hold
second
Dormant
minute
13
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
Active
SCH
millisecond
Active
FCH
Control/Hold
second
Dormant
minute
14
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
15
Inter BSC – Intra PDSN HHO
Source
MSC
BSC/PCF
User Packet Data
HO Required
HO Direction Msg
Target
BSC/PCF
PDSN
HO Request
Null Fwd Traffic
HO Request ACK
HO Command
Rev Traffic
HO Commenced
HCM
Tear Down Channels
Clear Command
A11 RRQ
A11 RRP
Clear Complete
A11 RRQ (Lifetime = 0)
A11 RRP
Handoff Complete
User Packet Data
16
Quality of Service
 Still standardization is continuing
 Air interface is bottleneck for an end-to-end
QoS
 Some parameters are defined such as



User’s priority level (14 possible levels)
Minimum acceptable data rate (2x, 4x, …)
Acceptable FER (1%, 2%, 5%, 10%)
17
1x EV-DV
(1xRTT Evolution for
high-speed integrated
Data and Voice)
18
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 asymmetric
nature of the data applications
 Flexibility against short term and long term
voice and data demands
19
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
20
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
21
What’s needed?
 Radio resources should be optimally used
 Radio link control & resource allocation must
be optimized
22
How is it achieved? (1/3)
Base Station Power
100%
Residual power for 1x EV-DV
1xEV-DV
overhead
Power for 1x voice and data
1x overhead
Time
Packet Data Common Channel is introduced
23
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
24
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
25
What’s next?
 Reverse link data enhancements are
necessary to meet the requirements, i.e. 1.25
Mbps
 Common services and mobility with different
type of network access technologies, such as
Wireless LANs, DSL, satellites etc.
26
4G
 Higher data rates ~2-20 Mbps
 New air interface needs to be developed
 Potential candidate OFDM
 Smart antennas can form directed beams to
increase strength of the desired signal
 A new spectrum needs to be assigned
 Software radio can transmit over different air
interface technologies
 All-IP vision: base stations become an access
router
27