EDCH
Short Description
EDCH doc...
Description
Enhanced Uplink Dedicated Channel (EDCH) High Speed Uplink Packet Access (HSUPA)
EDCH Background & Basics Channels/ UTRAN Architecture Principles: Hybrid ARQ, scheduling, soft handover RRM: Handover, Resource Allocation Performance Results
Background
E-DCH E DCH is a Rel-6 Rel 6 feature with following targets Improve coverage and throughput, and reduce delay of the uplink dedicated transport channels Priority given to services such as streaming, interactive and background services, conversational (e.g. VoIP) also to be considered Full mobility support with optimizing for low/ medium speed Simple implementation Special focus on co-working with HSDPA Standardization started in September 2002 Study item completed in February 2004 Stage II/ III started in September/ December 2004 Release 6 frozen in December 2005/ March 2006 Various improvements p have been introduced in Rel-7 & Rel-8
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
2
E-DCH Basics E DCH is a modification of DCH – Not a shared channel, E-DCH channel such as
HSDPA in the downlink !!
PHY taken from R99 Turbo coding and BPSK modulation Power Control 10 msec/ / 2 msec TTI Spreading on separate OVSF code, i.e. code mux with existing PHY channels MAC similarities to HSDPA Fast scheduling Stop and Wait HARQ: but synchronous New principles p p Intra Node B “softer” and Inter Node B “soft” HO should be supported for the E-DCH with HARQ Scheduling distributed between UE and NodeB
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
3
E-DCH Scheduling
UE
NodeB Scheduling information
UE detects data in buffer
Scheduling grant
Scheduler takes UE for scheduling
DATA Scheduling grant
UE sends scheduling information
MAC e signaling MAC-e
On E-DPCCH: “happy bit”
Scheduling grant
NodeB allocates the resources
Ab l t / relative Absolute/ l ti scheduling h d li grants t
Algorithms left open from standards
Scheduling information
Depending on the received grants, UE decides on transmission
Maintains allocated ll d resources by b means off internall serving grants
Selects at each TTI amount of E-DCH data to transmit
Algorithms fully specified by UMTS standard
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
4
E-DCH Scheduling Principle
UL Load target UE #m
Serving S i E-DCH users UE #1
Non-serving E-DCH users
Non E-DCH
UMTS Networks
E-DCH scheduler constraint Keep UL load within the limit Scheduler controls: E-DCH load portion from nonserving users of other cells E-DCH resources from each serving user of own cell Non E E-DCH DCH load portion DCH, RACH, HS-DPCCH May include non-scheduled E-DCH Controlled by y legacy g y load control,, e.g. Admission/ Congestion control Notes: E-DCH users transmit asynchronously h l Each UE owns whole code tree
UL Load
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
5
UMTS Channels with E-DCH
Cellll 1 C = Serving E-DCH cell
C ll 2 Cell UE
Rel-6 E-DCH (in SHO) UL PS service (DTCH) UL Signalling (DCCH)
UMTS Networks
R99 DCH (in SHO) UL/DL signalling (DCCH) UL/DL CS voice/ data Rel-5 HS-DSCH (not shown) DL PS service (DTCH) DL signalling (Rel-6, (Rel 6 DCCH)
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
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E-DCH Channels
E-DPDCH E DPDCH Carries the data traffic Variable SF = 256 … 2 UE supports up to 4 E-DPDCH E-DPCCH Contains the configuration as used on E E-DPDCH DPDCH Fixed SF = 256 E-RGCH/ E RGCH/ E E-HICH HICH E-HICH carries the HARQ acknowledgements E-RGCH carries the relative scheduling g grants g Fixed SF = 128 Up to 40 users multiplexed onto the same channel by using specific signatures E-AGCH Carries the absolute scheduling grants Fixed d SF = 256
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
7
Timing Relation (UL)
Downlink DPCH
CFN+1
CFN
15 × Tslot (10 msec) Uplink p DPCCH
E-DPDCH/ E DPCCH E-DPCCH
0.4 × Tslot (1024 chips) ±148chips
CFN
10 msec
10 msec TTI 2msec TTI
Subframe #0
Subframe #1
Subframe #2
Subframe #3
Subframe #4
3 × Tslot (2 msec)
E-DPDCH/ E-DPCCH time-aligned to UL DPCCH
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
8
HSUPA UE Categories E-DCH Category
Max. num. Codes
Min SF
EDCH TTI
Maximum MAC-e TB size
Theoretical maximum PHY data 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 2.89
Category 5
2
SF2
10 msec
20000
2.0
Category 6
4
SF2
10 msec/ 2 msec
20000/ 11484
2.0/ 2 0/ 5.74
Category 7 (Rel 7) (Rel.7)
4
SF2
10 msec/ 2 msec
20000/ 22996
2.0/ 11 5 11.5
When 4 codes are transmitted,, 2 codes are transmitted with SF2 and 2 with SF4 UE Category 7 supports 16QAM UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
9
E-DCH UTRAN Architecture
Evolution from Rel-5 • E-DCH functionality is intended for transport of dedicated logical channels (DTCH/ DCCH)
SRNC
RRC RLC DCCH DTCH
Logical Channels
MAC-es
E-DCH in Rel-6
MAC-d flows
CRNC
• RLC unchanged (UM & AM) • New MAC-es entity with link to MAC-d • New MAC-e entity located in the Node B
BCCH
MAC-d MAC-d flows
w/o o MAC-c/sh
• Additions in RRC to configure E-DCH
PDCP
DCH
Upper phy
MAC-c/sh
NodeB MAC-e Transport Channels
EDCH
MAC-b
MAC-hs DSCH FACH
HS-DSCH
BCH
• MAC-e entities from multiple NodeB may serve one UE ((soft ft HO)
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
10
MAC-e/es in UE
To MAC-d
MAC – Control
MAC-es/e E-TFC Selection
Multiplexing
MAC-e/es Functions Priority handling Per logical channel
HARQ
Associated Scheduling Downlink Signalling (E-AGCH / E-RGCH(s))
Associated ACK/NACK signaling (E-HICH)
UL data (E-DPDCH)
Associated Uplink Signalling: E-TFCI, RSN, happy bit (E-DPCCH)
Multiplexing MAC-d flow concept Mux of data from multiple MAC-d flows into single MAC-e PDU Scheduling Maintain scheduling grant E-TFC selection HARQ handling
Cf. 25.309 UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
11
MAC-e in NodeB
MAC-e Functions Per user HARQ handling: ACK/ NACK generation De-multiplexing E-DCH E DCH control: t l Rx/ Tx control signals
MAC-d Flows
UE #N UE #2 MAC – Control
UE #1 E-DCH
De-multiplexing
Control E-DCH Scheduling
HARQ entity
MAC-e E-DCH
Cf. 25.309 UMTS Networks
Common RG
Associated Uplink Signalling
Associated Downlink Signalling
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
E-DCH scheduling for all users Assign resources (scheduling grants) Iub overload control
12
MAC-es in SRNC
To MAC-d
MAC-es Functions MAC-es
Disassembly
Reordering/ Combining Co b g
Disassembly
Reordering/ Combining Co b g
Reordering Queue Distribution
MAC-d flow #1
Disassembly
Queue distribution
Reordering
MAC – Control C t l
Reordering/ Combining Co b g
Cf. 25.309 UMTS Networks
Per logical channel
In-sequence delivery
Reordering Queue Distribution
MAC-d flow #n
From MAC-e in NodeB #1
Macro-diversity combining: g frame selection
Disassembly
From MAC-e in NodeB #k
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
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Data Flow through Layer 2
RLC
RLC PDU:
Header
DATA
MAC-d MAC-d MAC d PDU:
MAC-es PDU:
MAC-e/es
DATA
TSN
DATA
DATA
DDI
N
DDI
N
MAC-e header
DDI
DATA
DATA
Padding (Opt)
MAC-es PDU
DDI: Data Description Indicator (6bit)
MAC-d PDU size
Log. Channel ID
Mac-d flow ID
N: N N Number b off MAC MAC-d d PDUs PDU (6bit) TSN: Transmission Sequence Number (6bit)
MAC-e PDU:
PHY
UMTS Networks
DATA
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
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Hybrid ARQ Operation
N-channel parallel HARQ with stop-and-wait protocol Number of HARQ processes N to allow uninterrupted E-DCH transmission 10 msec TTI: 4 2 msec TTI: 8 Synchronous y retransmissions Retransmission of a MAC-e PDU follows its previous HARQ (re)transmission after N TTI = 1 RTT Incremental Redundancy via rate matching Max. # HARQ retransmissions specified in HARQ profile
ACK NACK ACK NACK
New Tx 1 New Tx 2 New Tx 3 New Tx 4
Re-Tx 1
New Tx 2
Re-Tx 3
New Tx 4
Re-Tx 1
Re-Tx 2
NACK NACK
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
15
E-DCH UE Scheduling
UE maintains internal serving grant SG SG are quantized Maximum E-DPDCH/ DPCCH power ratio (TPR), which are defined by 3GPP Reception of absolute grant: SG = AG No transmission: SG = “Zero_Grant” Reception p of relative grants: g increment// decrement index of SG in the SG table AG and RG from serving RLS can be activated for specific HARQ processes for 2msec sec TTI UE selects E-TFC at each TTI Allocates the E-TFC according to the given restrictions Serving S i grantt SG UE transmit power Provides priority between the different logical channels
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
16
Scheduling Grant Table
Index
Scheduled Grant 2 (168/15) *6 2 (150/15) *6 2 (168/15) *4 2 (150/15) *4 2 (134/15) *4 2 (119/15) *4 2 (150/15) *2 2 (95/15) *4 2 (168/15)
37 36 35 34 33 32 31 30 29 • • •
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 UMTS Networks
2
(30/15) 2 (27/15) 2 (24/15) 2 (21/15) 2 (19/15) 2 (17/15) 2 (15/15) 2 (13/15) 2 (12/15) 2 (11/15) 2 (9/15) 2 (8/15) 2 (7/15) 2 (6/15) 2 (5/15)
Scheduling grants are max. E-DPDCH/ DPCCH power ratio (TPR – t ffi tto pilot traffic il t ratio) ti ) Power Ratio is related to UE data rate Relative Grants SG moves up/ down when RG = UP/ DOWN Absolute Grants SG jumps to entry for AG 2 reserved values for ZERO_GRANT/ INACTIVE
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
17
E-DCH Scheduling Options
ra ate
Time Scheduling
ra ate
Rate Scheduling
UE2 UE1 UE1
UE2
UE3
time
UEs are continuously active Data rate is incremental increased/ decreased by relative scheduling grants N synch No hb between t UE UEs required i d Load variations can be kept low For low to medium data rates
UMTS Networks
UE1
UE3
time
UEs are switched on/ off by absolute scheduling grants UEs should be in synch L d variations Load i ti might i ht be b large l (verry) high data rates
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
18
Timing Relation for Scheduling Grants
Scheduling decision E-RGCH E-AGCH
Load estimation, etc
E-DCH
1
2
3
HARQ process number
4
1
2
3
• AG applied to this HARQ process • RG interpreted relative to the previous TTI in this HARQ process.
AG and RG associated with specific uplink E-DCH TTI, i.e. specific HARQ process Association based on the timing of the E-AGCH E AGCH and E-RGCH. E RGCH Timing is tight enough that this relationship is un-ambiguous. Example: 10msec TTI
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
19
Scheduling Information
Happy bit signaling One bit status flag send on E-DPCCH at each TTI Criterion for happy bit Set to “unhappy” if UE is able to send more data than given with existing serving grant Otherwise Oh i set to “happy” “h ” Scheduling Information Reporting Content of MAC MAC-e e report Provides more detailed information (log. channel, buffer status, UE power headroom) Will be sent less frequently (e.g. every 100 msec) Parameters adjusted by RRC (e.g. reporting intervals, channels to report)
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
20
HSUPA Resource Allocation
Node B resources -decoding decoding capability -Iub bandwidth capacity Capabilities of the UEs -MAC-e MAC e PDU size limits -SF limits
Cell resources -Admissible uplink noise rise/load -CAC via RNC -Number AGCH/RGCH QoS parameters -Throughput Throughput bounds
E-DCH Radio Resource Management “E-RRM” -Keep uplink load within the limit -Control E-DCH load portion from nonserving users of other cells -Control E-DCH resources from each serving user of own cell -Satisfy QoS/ GoS requirements (Ranking PF/SW) -Maximize HSUPA cell throughput
Task: assigns Serving Grants (relative or absolute grants) in terms of a power offset to the current DPCCH power to the UEs in order to control the maximum data rate
Finally, the UE decides by itself on the used power ratio and the transport block size taking into account the restrictions sent by Node B
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
21
NodeB Scheduling Principle
UL Load
UL Load target UE #m
E-DCH scheduler constraint
Scheduler controls:
Serving S i E-DCH users
UE #1
Non-serving E-DCH users
Non E-DCH
Keep UL load within the limit E-DCH E DCH load portion of non-serving non serving users from other cells E-DCH resources of each serving user of own cell
Principles:
Rate vs. time scheduling
Dedicated control for serving users
Common control for non-serving users
Note: Scheduler cannot exploit fast fading !
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
22
Non-scheduled Mode
Configured by the SRNC
UE is allowed to send E-DCH data at any time
Signaling overhead and scheduling delay are minimized
Support of QoS traffic on E-DCH, e.g. VoIP & SRB
Characteristics
Resource given by SRNC:
Non-scheduled Grant = max. # of bits that can be included in a MAC-e PDU
UTRAN can reserve HARQ processes for non-scheduled transmission
Non-scheduled transmissions defined per MAC-d flow
Multiple non-scheduled MAC-d flows may be configured in parallel One specific non-scheduled MAC-d flow can only transmit up to the nonscheduled grant configured for that MAC-d flow
Sc edu ed g Scheduled grants a ts will be co considered s de ed o on top o of non-scheduled o sc edu ed transmissions
UMTS Networks
Scheduled logical channels cannot use non-scheduled grant
Non scheduled logical channels cannot transmit data using Scheduling Grant Non-scheduled
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
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E-DCH Operation in Soft Handover
scheduling grant HARQ ACK/ NACK
scheduling grant HARQ ACK/ NACK
UE NodeB 1
NodeB 2
Macro-diversity Macro diversity operation on multiple NodeBs Softer handover combining in the same NodeB Soft handover combining in RNC (part of MAC-es) I d Independent d MAC-e MAC processing i in i both b h NodeBs N d B HARQ handling rule: if at least one NodeB tells ACK, then ACK Scheduling rule: relative grants “DOWN” from any NodeB have precedence d
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
24
Mobility Handling
The UE uses soft handover for associated DCH as well as for E E-DCH DCH Using existing triggers and procedures for the active set update (events 1A, 1B, 1C) E-DCH active set is equal or smaller than DCH active set
New event 1J: non-active E-DCH link becomes better than active one
The UE receives AG on E-AGCH E AGCH from only one cell out of the E-DCH E DCH active set (serving E-DCH cell) Rel-6: E-DCH and HSDPA serving cell must be the same Hard H dH Handover, d ii.e. change h off serving i E-DCH E DCH cellll Using RRC procedures, which maybe triggered by event 1D
UMTS Networks
Could be also combined with Active Set Update
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
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Mobility Procedures
SRNC
SRNC
MAC-es
MAC-es
MAC-e
MAC-e
MAC-e
MAC-e
NodeB
NodeB
NodeB
NodeB
s
t Serving S i E-DCH radio link
Serving E-DCH radio link
Inter-Node B serving E-DCH cell change within E-DCH active set Note: MAC MAC-e e still established in both NodeBs !
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
26
E-DCH State Transitions
Reuse of the DCH state transition framework Move to Cell_FACH in case of decreased traffic amount Move back from Cell_FACH in case of increased traffic amount Transition to URA_PCH in case of inactivity Preferred combination: E-DCH/ HSDPA Transition to DCH In case of handover to cells not supporting E-DCH Service specific triggers
Cell DCH HSDPA/ DCH
Cell DCH HSDPA/ EDCH
Cell FACH, URA_PCH, …
Cell DCH DCH/ DCH
IDLE UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
27
E-DCH RRM Principle
UL Load
UL Load target
Serving S i E-DCH users Non-serving E-DCH users
Non E-DCH
UMTS Networks
Non E-DCH load portion
E-DCH resources controlled by UL load target Derived from RTWP target/ reference background noise NodeB internal load target E-DCH non-serving load portion Equivalent to target non nonserving E-DCH to total E-DCH power ratio NodeB schedules E-DCH users according di to t RNC settings tti Priority for non E-DCH traffic RNC still controls non E-DCH load portion By means of e.g. admission/ congestion control Based on either of the following To be derived from RTWP OR Measure of non-EDCH load
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
28
E-DCH Performance & Capacity
E-DCH E DCH offers improved throughput due to HARQ gain Faster scheduling with tighter UL load control The additional PHY channels consume resources UL load: DPCCH, E-DPCCH DL power/ codes: E-HICH/ E-RGCH, E-AGCH
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
29
User Throughput vs. Aggregate Cell Throughput
10ms TTI, unlimited CE dec. rate
1
1200
2ms TTI, next release
#UEs/cell
2 User Throughput [kbps]
1000
3 800
4
5
600
400
200
10
6 7 8 9
0 200
400
600
800
1000
1200
1400
1600
36 cells network UMTS composite channel model FTP ttraffic ffi model d l (2 Mbyte Mb t upload, 30 seconds thinking time) Maximum M i cellll throughput th h t reached for about 7…8 UEs per cell
Cell throughput drops if #UEs increases further since the associated signaling channel consume UL resources too
Aggregated Cell Throughput [kbps]
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
30
Single User Performance
2ms,, 1Tx
10ms,, 1Tx
3500
Avera age User Throu ghput [kbps]
3000
2500
2000
Average user throughput ((RLC C layer) aye ) for o different d ee channel profiles
1 UE in the network
1 target g HARQ Q transmission
For AWGN channel conditions:
1500
1000
500
10ms TTI: up p to 1.7 Mbps p (near theoretical limit of 1.88 Mbps) 2ms TTI: up to 3 Mbps (b l (below theoretical th ti l limit li it 5.44 5 44 Mbps)
0 AW GN
PedA3
PedA30
VehA30
VehA120
E.g. due to restrictions y ((window from RLC layer size, PDU size)
Scenario
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
31
E-DCH Summary
New uplink transmission concept Optimized for interactive, background and streaming, support of conversational Full support of mobility with optimizing for low/ medium speed Improved PHY approach New UL transport p channel: E-DCH Additional signalling channels to support HARQ and E-DCH scheduling MAC-e/es entity located in NodeB/ SRNC Distributed E E-DCH DCH scheduling between UE and NodeB E-DCH supports soft/ softer HO Radio Resource Control procedures similar to HSDPA E-DCH Resource Management Cumulated resources managed by Controlling-RNC Re Re-use use of principles for DCH control (handover (handover, state transition) Significant improved performance
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
32
References
Papers
A. Ghosh et al: “Overview of Enhanced Uplink for 3GPP W-CDMA,” Proc. IEEE VTC ’04/ Milan, vol. 4, pp. 2261–2265 H. Holma et al: “HSDPA/ HSUPA for UMTS,” Wiley 2006
Standards
TS 25.xxx 25 xxx series: RAN Aspects
TR 25.896: “Feasibility Study for Enhanced Uplink for UTRA FDD”
TR 25.808: “FDD Enhanced Uplink; p ; Physical y Layer y Aspects” p
TR 25.309/ 25.319 (Rel.7 onwards): “(FDD) Enhanced Uplink: Overall Description (Stage 2)”
UMTS Networks
Andreas Mitschele-Thiel, Jens Mückenheim
WS 2008
33
Abbreviations ACK AG AM AMC BO CAC CDMA DBC DCH DDI DPCCH E-AGCH E AGCH E-DCH E-HICH Indicator E-RGCH E-TFC FDD FEC FIFO FP GoS HARQ IE MAC d MAC-d MAC-e/es UMTS Networks
(positive) Acknowledgement Absolute Grant Acknowledged (RLC) Mode Adaptive Modulation & Coding Buffer Occupancy Call Admission Control Code Division Multiple Access Dynamic Bearer Control Dedicated Channel Data Description Indicator Dedicated Physical Control Channel E-DCH E DCH Absolute Grant Channel Enhanced (uplink) Dedicated Channel E-DCH HARQ Acknowledgement Channel E-DCH Relative Grant Channel E-DCH Transport Format Combination Frequency Division Duplex Forward Error Correction First In First Out F Framing i Protocol P t l Grade of Service Hybrid Automatic Repeat Request Information Element dedicated Medium Access Control E-DCH Medium Access Control
Mux NACK NBAP OVSF PDU PHY PO QoS Qo QPSK RB RG RL RLC RLS RRC RRM RV SDU SF SG SI TNL TPR TTI UM
Andreas Mitschele-Thiel, Jens Mückenheim
Multiplexing Negative Acknowledgement NodeB Application Part Orthogonal Variable SF (code) Protocol Data Unit Physical Layer Power Offset Qualityy of Qua o Service Quadrature Phase Shift Keying Radio Bearer Relative Grant Radio Link Radio Link Control Radio Link Set Radio Resource Control Radio Resource Management Redundancy Version Service Data Unit Spreading Factor Serving Grant Scheduling Information Transport Network Layer Traffic to Pilot Ratio Transmission Time Interval U Unacknowledged k l d d (RLC) Mode M d
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