WCDMA Air Interface Training (Part 5)
WCDMA Air Interface Training (Part 5)
WCDMA Air Interface Training (Part 5)
Part 5
WCDMA Acquisition,
Synchronization,
and Handover
Slot Synchronization
Frame Synchronization
Soft Handover
Inter-Frequency Handover
Secondary CCPCH
t S-CCPCH,k k:th S-CCPCH
(Paging, Signaling) t PICH
X 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Q
Y 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Initial Conditions:
PSC
Broadcast Data (18 bits)
SSCi
Broadcast by BS
First 256 chips of every SCH time slot
SCH BCH
256 Chips 2304 Chips
PSC
Broadcast Data (18 bits)
SSCi
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
SSC9 Group 63 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16
SSC10 Group 64 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10
SSC11
SSC12
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
SSC13
SSC14 1 Frame = 15 slots = 10 mSec
SSC15 Note:
SSC16 The SSC patterns positively identify one and only one of the 64 Scrambling Code Groups.
This is possible because no cyclic shift of any SSC is equivalent to any cyclic shift of any other SSC.
PSC BCH PSC BCH PSC BCH PSC BCH PSC BCH Matched Filter
[1] Data [2] Data [3] Data [4] Data [15] Data (Matched to PSC)
P-CCPCH
(PSC)
Matched
Filter
Output
time
SSC BCH SSC BCH SSC BCH SSC BCH SSC BCH
[1] Data [2] Data [3] Data [4] Data [15] Data
Matched Filter
SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] Matched to SSC
code group pattern
SSC Code Group Pattern provides
time
RACH
AICH
4096 chips
(1.066 msec) Pre- RACH
Pre- amble
Pre- amble message part
UE amble (UE Identification)
BS No No Acq.
Ind. Ind. Ind.
The power offset DPp-m between preamble and the message part.
• Preamble = [ P0, P1, … P15 ] repeated 256 times (4096 chips total).
• Preamble codes help the BS distinguish between UE making simultaneous Random Access Attempts.
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
20 ms
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
P Message
P = Random Access Transmission
P
5120 chips
UE Monitors Secondary SCH code, detects SCG and frame start time offset
UE in Idle Mode
AICH
DPCCH
AP CDP
AP
PCPCH
Power Control Uplink Data Packet
Preamble ‘N’ x 10 msec Frames
(0 or 8 slots)
1024 chips
8 bits/slot
4096 chips
SF = 256
Higher layers provide
mapping of status
(Transmission Off) b0 b1 b2 b3 b4 b5 b6 b7
indicators to availability
of CPCH resources
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
20 ms
API’s are derived from the UE’s CPCH Access Preamble Signature
Identifies the UE which is the target of the AP-AICH response
15
a j API s bs , j
s 0 1024 chips
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
20 ms
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
20 ms
SC1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
BS 2
CPICH 2 CPICH 2 CPICH 2 CPICH 2
BS 1
10 msec DPCCH/DPDCH DPCCH/DPDCH DPCCH/DPDCH DPCCH/DPDCH
frame
Toffset
Core Network
Iu Iu
RNS RNS
Iur
RNC RNC
UTRAN Iub
Iub Iub Iub
Vocoder
Time
Alignment
UTRAN
RNS RNS
RNC RNC
Transport Channel
Frame Alignment
Node B Node B Node B Node B Node B Node B
Radio
Synchronization
UE
BS 2
CPICH 2 CPICH 2 CPICH 2 CPICH 2
BS 1
10 msec
frame
UTRAN
UTRAN Commands BS2 to UE Rake Receiver UE in soft handover When BS2 sufficiently
adjust DPCH timing by Synchronizes to BS2 with BS1 and BS2 strong, drop BS1.
Toffset DPCCH/DPDCH DPCCH/DPDCH’s (Handover complete)
BS 2
CPICH 2 CPICH 2 CPICH 2 CPICH 2
BS 1
10 msec DPCCH/DPDCH DPCCH/DPDCH DPCCH/DPDCH DPCCH/DPDCH
frame
Puncturing bits
– weakens FEC coding
Normal Operation
11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6
Transmission Gap
Transmission Gap
1 2 3 4 5 6 7 8 9 10 11 12
T T T T T T T T T T T S T T T T T T T T T T T T T I
T = Traffic Frame
S = SACCH Frame
I = Idle Frame