Transcript Part 2: Principle and Implementation of EVDO Systems

Part 2: Principle and Implementation
of EVDO Systems
WLL SHORT TRAINING
UNIT 1
UNIT 2
EVDO Theory Unit 1
1X EVDO Network Structure
Source
AN
PCF
PDSN
AT
A12
Target
AN
AAA
AN AAA
IP Network
AT
AN
IP
Network
Comparison of EVDO and 1x Networks
HLR
AAA
MSC
MS/AN
BTSB
BSCB
ANAAA
PCF
PDSN
Network Implementation
Changed Parts in Upgrading
• BTS side:
•
- If new EVDO carrier is added
• Add EVDO base band processing part
• Add related Radio transmission part, keep
antenna and feeder.
• - If upgrading 1x carrier to EVDO carrier
• Add EVDO base band processing part
• Keep antenna and feeder no change
Changed Parts in Upgrading (Cont.)
• BSC side: add EVDO processing part,
upgrade related software
• - EVDO Signaling
• -Increased EVDO data capacity
UNIT 1
UNIT 2
EVDO Channel Structure & Key
Techniques
• Forward Link Channel Structure
• Reverse Link Channel Structure
• Key Techniques
Forward Channel Structure
Forward
Pilot
Reverse
Activity
Channel
Medium
Access
Control
DRC Lock
Traffic
Reverse
Power
Control(RPC)
Control
Forward Data Time Slot
Forward Pilot Channel
 The Pilot channel is
sent as 96 chip
bursts, each of
which is located at
the center of each
half slot.
 The Pilot channel is
transmitted at the
full sector power.
Forward MAC Channel
•
•
•
•
•
The Reverse Power Control Channel (RPC channel)
and the DRCLock Channel are time-division
multiplexed.
RPC channel is used for reverse power control.
DRCLock is used to indicate if the reverse Date Rate
Control (DRC) channel message is received or not.
Reverse Activity (RA) channel is CDMed with RPC
channel + DRCLock channel
Reverse Activity Bit (RAB) is transmitted in RA
channel, which is broadcasted by AN to inform ATs
the current reverse traffic channel status.
MAC Index
Forward Control Channel
Forward Control Channel
• Data rate is 38.4 or 76.8kbps.
• The Control Channel Cycle is of 256 slots.
• Broadcast Overhead messages and Page
messages are always delivered by using
Synchronous Capsule (AC).
• Asynchronous Capsule (AC) used to deliver
ACK messages and RLP Control messages,
may be sent at any time during which the AN
is not sending a synchronous capsule.
Forward Traffic Channel
• Supported data rates: 38.4, 76.8, 153.6, 307.2,
614.6, 921.6, 1228.8, 1843.2, and 2457.6 Kbps.
• QPSK, 8PSK and 16-QAM are used.
• Channel encoders with different code rates are
used.
• Physical layer packets are of four different lengths:
1024 bits, 2048 bits, 2072 bits and 4096 bits.
• A preamble is attached as the header of each
physical layer packet.
• The transmitted packet = preamble + physical
layer packet
Forward Traffic Channel Parameters
Data rate
(kbps)
Slots
per
Packet
Packet
Size
(bits)
Code
Rate
Repetition
Modulation
Preamble
(chips)
Effective code
Rate
38.4
16
1024
1/5
9.6
QPSK
1024
1/48
76.8
8
1024
1/5
4.8
QPSK
512
1/24
153.6
4
1024
1/5
2.4
QPSK
256
1/12
307.2
2
1024
1/5
1.2
QPSK
128
1/6
307.2
4
2048
1/3
49/48
QPSK
128
16/49
614.4
1
1024
1/3
1
QPSK
64
1/3
614.4
2
2048
1/3
49/48
QPSK
64
16/49
921.6
2
3072
1/3
49/48
8PSK
64
16/49
1228.8
1
2048
1/3
0.5
QPSK
64
2/3
1228.8
2
4096
1/3
49/48
16QAM
64
16/49
1843.2
1
3072
1/3
0.5
8PSK
64
2/3
2457.6
1
4096
1/3
0.5
16QAM
64
2/3