enhanced high-speed packet access hspa+_ws12.pdf · umts networks andreas mitschele-thiel, jens...
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Enhanced High-Speed Packet AccessHSPA+
u Background: HSPA Evolutionu Higher data ratesu Signaling Improvementsu Architecture Evolution/ Home NodeB
UMTS Networks 2Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSPA+ (HSPA Evolution) Background
u For operators deploying High Speed Packet Access (HSPA*) now, there is theneed to continue enhancing the HSPA technologyu 3GPP Long Term Evolution (LTE) being standardized now, but not
backwards compatible with HSPAu 477 HSDPA networks in service in 177 countries (Oct. 12)**u Investment protection needed for current HSPA deployments
u HSPA+ effort introduced in 3GPP in March 2006u Initiated by 3G Americas & the GSMAu HSPA+ defines a broad framework and set of requirements for the
evolution of HSPAu Rel.-7: improvements mainly in downlinku Rel.-8: mainly uplink enhancementsu Rel.-9/10: further improvements
*HSPA is the combination of HSDPA and HSUPA**http://www.4gamericas.org -> Statistics
UMTS Networks 3Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSPA+ Goals
Based on the importance of the HSPA-based radio network, 3GPPagreed that HSPA+ should:
u Provide spectrum efficiency, peak data rates & latency comparable toLTE in 5 MHz
u Exploit full potential of the CDMA air interface before moving to OFDM
u Allow operation in an optimized packet-only mode for voice and datau Utilization of shared channels only
u Be backward compatible with Release 99 through Release 6u Offer a smooth migration path to LTE/SAE through commonality, and
facilitate joint technology operationu Ideally, only need a simple infrastructure upgrade from HSPA to HSPA+u HSPA evolution is two-fold
u Improvement of the radiou Architecture evolution
UMTS Networks 4Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Higher Order Modulations (HOMs)
BPSK2 bits/symbol
16QAM4 bits/symbol
64QAM6 bits/symbol
Uplink Downlink
u Increases the peak data rate in a high SNR environmentuVery effective for micro cell and indoor deployments
UMTS Networks 5Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Peak Rate Performance Benefits of HSPA+
0
5
10
15
20
25
30
35
40
45
50
Peak
Thro
ughp
utin
Mbp
s
14
21
28
42
5.7
11.5
HSDPA
HSPA+64QAM
HSPA+16QAM
2x2 MIMO
HSPA+64QAM*
2x2 MIMO
HSUPA
HSPA+16QAM
Downlink
Uplink
*Release 8
Uplink and Downlink peakrates similar to LTE peakrates in 5 MHz
uMajor increase HSPA peakrates by Higher OrderModulations
uData rate benefits for usersin ideal channel conditions(e.g. static users, fixedusers close to the cellcenter, lightly loadedconditions)
UMTS Networks 6Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSDPA Performance with 64QAM
Without 64-QAM With 64-QAM Gain
Cell Throughput 6.9 Mbit/s 7.65 Mbit/s 10.7%
95%-tile User Throughput 7.1 Mbit/s 8.7 Mbit/s 22.5%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Cat 10/ 15 users Cat 14/ 15 users
thro
ughp
ut/k
bps
average user throughput 95% user throughput ave. cell throughput
Single micro-cell scenario, advanced receivers required
UMTS Networks 7Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
16-QAM for E-DCH
u 16-QAM being considered in the uplink for HSPA Evolution, for use with the2ms TTI and with 4 multicodes (2xSF2 + 2xSF4)u Increases peak rate from 5.76 Mbps to 11.52 Mbps
u Simulation results showed:u 16 QAM requires very high SNR at the receiveru 16 QAM can be used only in case of one single HSUPA active user per cell
BPSK
BPSK
BPSK
BPSK
SF2
SF2
SF4
SF4
I
Q
I
Q
SF2
SF4
16 QAM
I
Q
16 QAM
I
Q
UMTS Networks 8Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Coding/Modulation/Weighting/Mapping
Basic MIMO Channel
§ The HSDPA MIMO channel consists of 2 Tx and 2 Rx antennas§ Each Tx antenna transmits a different signal§ The signal from Tx antenna j is received at all Rx antennas i§ Channel capacity can be increased by up to a factor of two
Weighting/DemappingDemodulation/Decoding
Tx Rx
H
HVUH L=
UMTS Networks 9Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
MIMO in HSPA+
Release 7 MIMO for HSDPA (D-TxAA)u 2 x 2 MIMO schemeu 4 rank-1 precoding vectors and 4 rank-2 precoding matrices are defined
u The rank-2 matrices are unitary (the columns are orthogonal)u The mobile reports the rank of the channel and the preferred precoding
weights periodicallyu Dynamic switching between single stream and dual stream transmission is
supported by the NodeB scheduler
Weight Generation
w1 w4
Determine weight infomessage from the uplink
w2 w3
TrCHprocessing
HS-DSCH TrCHprocessing
HS-DSCH
Spread/scramble
Primarytransport block
Primary: Always present for scheduled UE
Secondary: Optionally present for scheduled UE
Secondarytransport block
å
Ant1
Ant2
å
CPICH1
CPICH2
w1
w2
w3
w4
å
å
UMTS Networks 10Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
MIMO Performance Benefits
u 2x2 D-TxAA MIMO scheme doubles peak rate from 14.4 Mbps to 28.8 Mbpsu 2x2 D-TxAA MIMO provides significant experienced peak, mean & cell edge
user data rate benefits for isolated cells or noise/coverage limited cellsu 2x2 D-TxAA MIMO provides 20%-60% larger spectral efficiency than 1x2
00.250.5
0.751
1.251.5
1.752
Near Cell Center Average CellLocation
Cell Edge
Data
Rat
eG
ain
ofM
IMO
vs.
SIS
Ofo
ran
Isol
ated
Cell SISO (1x1)
MIMO (2x2)Note: All gainsnormalized toNear Cell CenterSISO Data Rate
0
20
40
60
80
100
Interference LimtedSystem
Isolated Cell
Spec
tralE
ffici
ency
Gai
n(%
)of2
x2M
IMO
over
1x2
LMM
SE
UMTS Networks 11Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Overview of Dual Cell Operation
3GPP Rel-8 scope:u The dual cell operation only applies to downlink HS-DSCH
u Uplink traffic is carried in one frequencyu The two cells belong to the same Node-B and are on adjacent carriersu The two cells operate with a single TX antenna
u Max two streams per user
Improvements in Rel.-9u Dual-Band HSDPAu MIMO in dual cell operationu Dual Cell uplink
Multi-carrier HSDPA
Node-B
F1UEF2
DLDL
5 MHz 5 MHz
UL5 MHz
2.1GHzUL
UTRAN configures one of the cell as theserving cell for the uplink
UMTS Networks 12Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Dual Cell HSDPA Operation for Load Balancing
Dual Cell HSDPA can optimally balance the load on two HSDPA carriers by schedulingactive users simultaneously or on least loaded carrier at given TTI
Simple traffic and capacitymodel
Avg Transfer size : 1000 kbytes
Avg Time between transfers :60 sec
No gain at very high load
Dual Cell HSDPA operation versus Two legacy HSDPA carriers
0
1000
2000
3000
4000
5000
6000
7000
8000
0 10 20 30 40 50 60
Nb of users in sector footprint
Thro
ughp
utin
kbps
Avg user throughput (2 HSDPA carriers)Avg Sector throughput (2 HSDPA carriers)Avg user throughput (Dual Cell HSDPA operation)Avg Sector throughput (Dual Cell HSDPA operation)
UMTS Networks 13Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Enhanced Layer-2 Support for High Data Rates
u Release 6 RLC layer cannot supportnew peak rates offered by HSPA+features such as MIMO & 64-QAMu RLC-AM peak rate limited to ~13
Mbps, even with aggressivesettings for the RLC PDU size andRLC-AM window size
u Release 7 introduces new Layer-2features to improve HSDPAu Flexible RLC PDU sizeu MAC-ehs layer segmentation/
reassembly (based on radioconditions)
u MAC-ehs layer flow multiplexingu Release 8 improves E-DCH
u MAC-i/ MAC-is
Rel’7
2
1500 byte IP packet
RLC-AM
MAC-ehs
RLC-AM PDU
1500
15001
MAC-ehs PDU
Traffic flow i for user k
2
1500 byte IP packet
RLC-AM
RLC-AM PDU
1500
1500
Traffic flow j for user k
22 bits
802 802
1500 byte IP packet
RLC-AM
802
MAC-hs
802 802802
RLC-AM PDU
MAC-hs PDU
x19
..
.. Rel’6
Traffic flow i for user k
UMTS Networks 14Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
MAC-ehs in NodeB
MAC-ehs Functions (TS 25.321)u Flow Controlu Scheduling/ Priority handlingu HARQ handlingu TFRC Selectionu Priority Queue Muxu Segmentation
MAC-ehs
MAC – Control
HS-DSCH
TFRC selection
Priority Queuedistribution
Associated DownlinkSignalling
Associated UplinkSignalling
MAC-d flows
PriorityQueue
Scheduling/Priority handling
PriorityQueue
PriorityQueue
Segmentation
Segmentation
Segmentation
Priority Queue MUX
HARQ entity
UMTS Networks 15Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSDPA – UE Physical Layer Capabilities
HS-DSCHCategory
Maximumnumber ofHS-DSCH
multi-codes
Supported ModulationFormats
Minimuminter-TTIinterval
MaximumMAC-hsTB size
Total numberof soft channel
bits
Theoreticalmaximumdata rate(Mbit/s)
Category 6 5 QPSK, 16QAM 1 7298 67200 3.6Category 8 10 QPSK, 16QAM 1 14411 134400 7.2Category 9 15 QPSK, 16QAM 1 20251 172800 10.1Category 10 15 QPSK, 16QAM 1 27952 172800 14.0Category 13 15 QPSK, 16QAM, 64QAM 1 35280 259200 17.6Category 14 15 QPSK, 16QAM, 64QAM 1 42192 259200 21.1Category 15 15 QPSK, 16QAM 1 23370 345600 23.3Category 16 15 QPSK, 16QAM 1 27952 345600 28.0Category 17 15 QPSK, 16QAM, 64QAM/
MIMO: QPSK, 16QAM1 35280/
23370
259200/
345600
17.6/
23.3Category 18 15 QPSK, 16QAM, 64QAM/
MIMO: QPSK, 16QAM1 42192/
27952
259200/
345600
21.1/
28.0Category 19 15 QPSK, 16QAM, 64QAM 1 35280 518400 35.2Category 20 15 QPSK, 16QAM, 64QAM 1 42192 518400 42.2
Note: UEs of Categories 15 – 20 support MIMO cf. TS 25.306
UMTS Networks 16Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
E-DCH – UE Physical Layer Capabilities
E-DCHCategory
Max. num.Codes
Min SF EDCH TTI Maximum MAC-eTB size
Theoretical maximum PHYdata rate (Mbit/s)
Category 1 1 SF4 10 msec 7110 0.71
Category 2 2 SF4 10 msec/2 msec
14484/2798
1.45/1.4
Category 3 2 SF4 10 msec 14484 1.45
Category 4 2 SF2 10 msec/2 msec
20000/5772
2.0/2.89
Category 5 2 SF2 10 msec 20000 2.0
Category 6 4 SF2 10 msec/2 msec
20000/11484
2.0/5.74
Category 7(Rel.7)
4 SF2 10 msec/2 msec
20000/22996
2.0/11.5
NOTE 1: When 4 codes are transmitted in parallel, two codes shall betransmitted with SF2 and two codes with SF4NOTE 2: UE Category 7 supports 16QAM
cf. 25.306
UMTS Networks 17Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Continuous Packet Connectivity (CPC)
u Uplink DPCCH gating duringinactivity à significant reductionin UL interference
u F-DPCH gating during inactivity
u New uplink DPCCH slot formatoptimized for transmissionDPCCH only
DataPilot
u HS-SCCH-less transmission introduced to reduce signaling bottleneck for real-time-services on HSDPA
Prior to Rel-7
Rel-7 using CPC
DataPilot
UMTS Networks 18Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
CPC Performance Benefits
u CPC provides up to a factor of two VoIP on HSPA capacity benefit comparedto Rel-99 AMR12.2 circuit voice and 35-40% benefit compared to Rel-6 VoIPon HSPA
0
0.5
1
1.5
2
2.5
3
AMR12.2 AMR7.95 AMR5.9VoIP
Cap
acity
Gai
nof
CPC R'99 Circuit Voice
VoIP on HSPA (Rel'6)*VoIP on HSPA (CPC)*
Note: Allcapacity gainsnormalized toAMR12.2Circuit VoiceCapacity
* All VoIP on HSPA capacities assume two receive antennas in the terminal
UMTS Networks 19Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
“Always On” Enhancement of CPC
u CPC allows UEs in CELL_DCH to “sleep” during periods of inactivityu Reduces signaling load and battery consumption (in combination with DRX)
u Allows users to be kept in CELL_DCH with HSPA bearers configuredu Need to page and re-establish bearers leads to call set up delay
Incomingcall Page UE
PagingResponse
Re-establishbearers
Send data
Without CPC, userstypically kept inURA_PCH or CELL_PCHstate to save radioresources and battery
UE inURA_PCH
CPC allows users tokept in CELL_DCH
Send data almostImmediately
(<50ms reactivation)
Incomingcall
UE inCELL_DCH
Avoids several hundredms of call setup delay
CELL_FACH
CELL_DCH
UMTS Networks 20Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Enhanced CELL_FACH & Enhanced Paging Procedure
u UEs are not always kept in CELL_DCHstate, eventually fall back toCELL_PCH/URA_PCH
u HSPA+ introduces enhancements toreduce the delay in signaling thetransition to CELL_DCH à use ofHSDPA in CELL_FACH andURA/CELL_PCH states instead of S-CCPCHu Enhanced CELL_FACHu Enhanced Paging procedure
u In Rel.-8 improved RACH procedureu Direct use of HSUPA in CELL_FACH
Incomingcall Page UE
PagingResponse
Re-establishbearers
Send data
UE inURA_PCH
CELL_FACH
CELL_DCH
Use HSDPA forfaster
transmission ofsignalingmessages
à 2ms framelength with up to4 retransmissions
UMTS Networks 21Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
E-RACH – High level description
u RACH preamble ramping as in R’99 with AICH/E-AICH acknowledgementu Transition to E-DCH transmission in CELL_FACH
u Possibility to seamlessly transfer to Cell_DCHu NodeB can control common E-DCH resource in CELL_FACH
u Resource assignment indicated from NodeB to UE
10 ms
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4tp-
a
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4PRACHaccessslots
10 ms
Access slot set 1 Access slot set 2
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4
Transmission startswith power ramping
on preamblereserved for E-DCH
access
NodeB responds byallocating common E-DCH
resources
UE starts common E-DCHtransmission.
F-DPCH for power control, E-AGCHfor rate control, E-HICH for HARQ
UMTS Networks 22Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSPA+ Architecture Evolution
u Integration of some or all RNC functions into the NodeB provides benefits in terms of:u Network simplicity (fewer network elements)u Latency (fewer handshakes, particularly in combination with One-Tunnel)u Synergy with LTE (serving GW, MME, eNB)
u Backwards compatible with legacy terminalsu Central management of common resources
NodeB
RNC
SGSN
GGSN
Traditional HSPAArchitecture
User Plane
Control Plane
NodeB
RNC
SGSN
GGSN
HSPA with One-TunnelArchitecture
NodeB+
SGSN
GGSN
HSPA+ with One-TunnelArchitecture for PS services
UMTS Networks 23Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Evolved HSPA Architecture – Full RNC/NodeB collapse
u 2 deployment scenarios: standalone UTRAN or carrier sharing with “legacy”UTRAN
EvolvedHSPANodeB
SGSN
GGSN
Userplane: Iu/Gn(”one tunnel”)Control
plane: Iu
Iur
EvolvedHSPANodeB
SGSN
GGSN
Userplane: Iu/Gn(”one tunnel”)Control
plane: Iu
Iur
RNC
NodeBNodeB
” Legacy”UTRAN
Iu
Evolved HSPA- stand-alone Evolved HSPA- with carrier sharing
EvolvedHSPANodeB
SGSN
GGSN
Userplane: Iu/Gn(”one tunnel”)Control
plane: Iu
Iur
EvolvedHSPANodeB
SGSN
GGSN
Userplane: Iu/Gn(”one tunnel”)Control
plane: Iu
RNC
NodeBNodeB
” Legacy”UTRAN
Iu
Evolved HSPA- stand-alone Evolved HSPA- with carrier sharing
UMTS Networks 24Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Home NodeB – Background
u Home NodeB (aka Femtocell) located atthe customers premiseu Connected via customers fixed line
(e.g. DSL)u Small power (~100mW) to only
provide coverage inside/ close tothe building
u Advantagesu Improved coverage esp. indooru Single device for home/ on the
moveu Special billing plans (e.g. home
zone)
u Challengesu Interferenceu Securityu Costs
IP Network
UE
Gateway
OperatorCN
UMTS Networks 25Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
CN Interface
Iuh
Iu-CS/PS
Home NodeB architecture principles based on extending Iu interfacedown to HNB (new Iuh interface)
u Approach
u Leverage Standard CN Interfaces (Iu-CS/PS)
u Minimise functionality within Gateway
u Move RNC Radio Control Functions toHome NodeB and extend Iu NAS &RAN control layers over IP network
u Features
u Security architecture
u Plug-and-Play approach
u Femto local control protocol
u CS User Plane protocol
u PS User Plane protocol
u HMS interface
RNC HNB-GW
NodeB HNB
RAN Gateway Approach with new “Iuh” Interface
Mobile CS/PS Core
UMTS Networks 26Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSPA+ Status & Outlook
u The HSPA+ enhancements seem quite promising for network deploymentu Investment protection for the existing HSPA operatorsu Fill the gap before deployment of LTEu Provide alternatives to LTE in some selected areas
u Currently, 234 HSPA+ networks are in service in 113 countries(Oct 2012)**u Almost using 64QAM (often also with DC)u Only a few ones with MIMO
u 3GPP is working on further HSPA enhancementsu Release 10: 4-carrier HSDPAu Release 11: 8-carrier HSDPA, 4x4 HSDPA MIMO, HSDPA multipoint
transmission, UL MIMO + 64QAM
UMTS Networks 27Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
HSPA+ References
u Papers:u H. Holma et al: “HSPA Evolution,” Chapter 15 in Holma/ Toskala:
“WCDMA for UMTS,” Wiley 2010u R. Soni et al: “Intelligent Antenna Solutions for UMTS: Algorithms and
Simulation Results,” Communications Magazine, October 2004, pp. 28–39
u Standardsu TS 25.xxx series: RAN Aspectsu TR 25.308 “HSDPA: UTRAN Overall Description (Stage 2)”u TR 25.319 “Enhanced Uplink: Overall Description (Stage 2)”u TR 25.903 “Continuous Connectivity for Packet Data Users”u TR 25.876 “Multiple-Input Multiple Output Antenna Processing for
HSDPA”u TR 25.999 “HSPA Evolution beyond Release 7 (FDD)”u TR 25.820 (Rel.-8) “3G Home NodeB Study Item Technical Report”
UMTS Networks 28Andreas Mitschele-Thiel, Jens Mückenheim Nov. 2012
Abbreviations
AICH Acquisition Indicator ChannelAMR Adaptive Multi-RateBPSK Binary Phase Shift KeyingCLTD Closed Loop Transmit DiversityCPC Continuous Packet ConnectivityCQI Channel Quality InformationDSL Digital Subscriber LineE-RACH Enhanced Random Access ChannelF-DPCH Fractional Dedicated Physical Control
ChannelGW GatewayHNB Home NodeBHOM Higher Order ModulationHSPA High-Speed Packet-AccessIA Intelligent AntennaLTE Long Term EvolutionMAC-ehs enhanced high-speed Medium Access
ControlMAC-i/is improved E-DCH Medium Access
ControlMIMO Multiple-Input Multiple-Output
Mux Multiplexing
PARC Per Antenna Rate Control
PCI Precoding Control Information
PDU Protocol Data Unit
Rx Receive
RTT Round Trip Time
SDU Service Data Unit
SAE System Architecture Evolution
S-CPICH Secondary Common Pilot Channel
SDMA Spatial-Division Multiple-Access
SINR Signal-to-Interference plus Noise Ratio
SISO Single-Input Single-Output
SM Spatial Multiplexing
Tx Transmit
VoIP Voice over Internet Protocol
16QAM 16 (state) Quadrature AmplitudeModulation
64QAM 64 (state) Quadrature AmplitudeModulation