wcdma hspa
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MobileComm Professionals, Inc.
Your Partner for Wireless Engineering Solutions
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High Speed Packet Access
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MobileComm Professionals, Inc.
HSPA
HSUPA
HSDPA
Agenda
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MobileComm Professionals, Inc. HSPA Evolution
HSPA has improved performance and spectral efficiency in DL and UL by introducing a shared channel principle: Significant enhancement with peak rates up to 14.4 Mbps in DL Huge capacity increase per site; no site pre-planning necessary Improved end user experience: reduced delay/latency, high response time
Introduced by 3GPP in Dec. 99, WCDMA Based Tech., Matured GSM/GPRS CN, up to 384 kbps (2Mbps)
Rel.99 Rel. 4 Rel. 5 Rel. 6
Bearer independent CS Core Network, CAMEL Phase 4, low chip rate TDD mode, UTRA FDD Repeater .
HSDPA (14 Mbps), IMS phase 1, W-AMR, Location Services, 1800/1900 MHz
HSUPA (5.76 Mbps), IMS Phase 2, MMS enhancement, MBMS, WLAN-Internetworking
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MobileComm Professionals, Inc.
Peak data rates of HSDPA increased to significantly higher than 2 Mbps; Theoretically exceeding 10 Mbps.
Packet data throughput increased 50-100% compared to 3GPP release 4
Reduced delay from retransmissions.
Solutions
Adaptive Modulation and Coding
Layer1 hybrid ARQ
Short frame2 ms
Schedule in 3GPP
Part of Release 5
First specifications version completed 03/02
HSDPA Features
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MobileComm Professionals, Inc. HSDPA Principle
Fast Hybrid ARQ with Soft Combining
Reduced round trip delay
Fast Link Adaptation
Data rate adapted to radio conditions on 2 ms time basis
t
P
Dynamic Power Allocation
Efficient power & spectrum utilisation
Higher-order Modulation
16QAM in complement to QPSK for higher peak bit rates
HSDPA
Shared Channel Transmission
Dynamically shared in time & code domain
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MobileComm Professionals, Inc. Hybrid Automatic Repeat Request
Server RNC Node-B
UE
RLC retransmissions
TCP retransmissions
H-ARQ: MAC-hs Layer-1
retransmissions
Round-Trip Time: 16 ms
HARQ
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MobileComm Professionals, Inc. Dynamic Power Allocation
3GPP Release 99 3GPP Release 5
Dedicated channels (power controlled)
Common channels
Power usage with dedicated channels
t
Unused power
Power
To
tal
ce
ll p
ow
er
Dedicated channels (power controlled)
Common channels
Power usage with dedicated channels
t
Used for HSDPA
Power
To
tal
ce
ll p
ow
er
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MobileComm Professionals, Inc. Adaptive Modulation & Coding (1/3)
HSDPA uses: QPSK 16QAM Dynamically based on quality of the radio link
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MobileComm Professionals, Inc. Adaptive Modulation & Coding (2/3)
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MobileComm Professionals, Inc.
HSDPA adapts the Modulation to the current Radio Link Quality (Ec/Io) HSDPA uses: QPSK at low Radio Link Quality 16QAM at high Radio Link Quality
HSDPA adapts the Coding to the current Radio Link Quality (Ec/Io) HSDPA varies the Coding between 1/4 3/4 (theoretically 1/6 0.98)
Adaptive Modulation & Coding (3/3)
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MobileComm Professionals, Inc. Fast Link Adaptation
WCDMA used Power control to compensate for differences and variations in radio channel conditions.
So available o/p power was not fully used as power needed to be reserved for ongoing connections.
Surplus of o/p power cannot be used to increase the throughput of the system. HSDPA - Relies on bit-rate adjustment (known as Link Adaptation)
High data rate
Low data rate
Fast Radio Channel Dependent Scheduling
Scheduling of users on 2 ms time basis
2 ms
Short TTI (2 ms)
Reduced round trip delay
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MobileComm Professionals, Inc. Scheduling
Fast Scheduling in the Time domain (2): - Transmission is based on:
Channel Quality, UE Capabilities Current load in the cell (available resources / buffer status) Traffic Priority classes / QoS classes UE Feedback (ACK/NACK)
Fast Scheduling in the code Domain - Up to 15 codes in parallel per TTI
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MobileComm Professionals, Inc. Shared Channel Transmission
Channelization codes allocated
for HS-DSCH transmission
5 codes (example)
SF=16
SF=8
SF=4
SF=2
SF=1
User #1 User #2 User #3 User #4
TTI
Shared
channelization
codes
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MobileComm Professionals, Inc.
Multi Code Operation
C1,0 = [1]
C2,1 = [1-1]
C2,0 = [11]
C4,0 = [1111]
C4,1 = [11-1-1]
C4,2 = [1-11-1]
C4,3 = [1-1-11]
C8,1 = [1111-1-1-1-1]
C8,2 = [11-1-111-1-1]
C8,3 = [11-1-1-1-111]
C8,4 = [1-11-11-11-1]
C8,5 = [1-11-1-11-11]
C8,6 = [1-1-111-1-11]
C8,7 = [1-1-11-111-1]
C16,1 =
[.........]
C16,15 =
[........]
C16,14 =
[........]
C16,13 =
[........]
C16,12 =
[........]
C16,11 = [........]
C16,10 =
[........]
C16,9 =
[.........]
C16,8 =
[.........]
C16,7=
[.........]
C16,6 =
[.........]
C16,5 =
[.........]
C16,4 =
[.........]
C16,3 =
[.........]
C16,2 =
[.........]
C8,0 = [11111111] C16,0 =
[.........]
SF = 1 2 4 8 SF = 16 256 512 ...
Shared Channel Transmission
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MobileComm Professionals, Inc.
Peak data rates increased to significantly higher than 2 Mbps; Theoretically reaching 5.8 Mbps
Packet data throughput increased, though not quite high numbers expected as with HSDPA
Reduced delay from retransmissions.
Solutions Layer1 hybrid-ARQ Node B based scheduling for uplink Frame sizes 2ms & 10ms
Schedule in 3GPP Part of Release 6
HSUPA Features
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MobileComm Professionals, Inc.
HSUPA
Fast Power Control
Hybrid ARQ with incr.
redundancy NodeB Controlled
Scheduling
Shorter TTI [TTI = 10 ms or 2 ms]
HSUPA Principles
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MobileComm Professionals, Inc. Shorter Transmission Time Interval
10 ms TTI:
Improved cell edge
performance
2 ms TTI:
reduced latency
higher peak rates
(up to 5.8 Mbps)
The use of a shorter TTI within 3G HSPA reduces the round trip time and enables improvements in adapting to fast channel variations and provides for reductions in latency.
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MobileComm Professionals, Inc. Node B Controlled Scheduling
R6 E-DCH
Data
transmission
L3 Resource
Allocation
Scheduling Info
Scheduling
Assignment
DCH services
(eg voice and visio)
UE 2
UE 1
UE 1
UE 2
UE 3
UE 1
UE 2
UE 3
UE 1
TTI 0 TTI 1 TTI 2 TTI 3
RoT
Time
Maximum
allowable
noise rise
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MobileComm Professionals, Inc. H-ARQ
HARQ Mechanism
The Stop and Wait (SAW) protocol for multi-channel or multi-process is performed through four (TTI=10 ms) or eight (TTI=2 ms) processes.
Each Radio Link (RL) sends the feedback respectively. Each RL establishes one E-HICH. The E-HICH information sent by each Radio Links set (RLs) is the same and can be combined. If any E-HICHs return ACK, then the transmission succeeds
For Fast retransmissions
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MobileComm Professionals, Inc. HSDPA
SINR is used instead of Eb/No in HSDPA performance evaluation
Modulation and coding Bit rate can be changed every 2 ms
Definition of HS-DSCH SINR:
Narrowband signal-to-interference-plus-noise-ratio after
despreading of the HS-PDSCH
SINR includes the SF16 processing gain for the HS-PDSCH and the
effect of using orthogonal codes
Average HS-DSCH SINR:
This is the experienced HS-DSCH SINR by a user average over fast
fading.
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MobileComm Professionals, Inc. Required SINR
PDSCHHSSFI
CSINR
NothownDL PIII )1(
Where: C = received power Iown = total power received from the serving cell Ioth = total power received from other cells PN = noise power = orthogonality factor SFHS-PDSCH = Spreading factor on HSDPA (= 16)
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MobileComm Professionals, Inc. Channels Needed for HSDPA Operation
Iub
Node B RNC
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MobileComm Professionals, Inc.
UE
Iub Uu
Node B RNC
Channels Needed for HSUPA Operation
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MobileComm Professionals, Inc.
HSPA
HSUPA
HSDPA
Summary
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MobileComm Professionals, Inc.
HAPPY LEARNING
MobileComm Professionals, Inc. www.mcpsinc.com
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