Enhanced Uplink Dedicated Channel (EDCH)
Enhanced Uplink Dedicated Channel (EDCH)
High Speed Uplink Packet Access (HSUPA)
High Speed Uplink Packet Access (HSUPA)
EDCH Background & Basics Channels/ UTRAN Architecture
Principles: Hybrid ARQ, scheduling, soft handover RRM: Handover, Resource Allocation
Background
E DCH is a Rel 6 feature with following targets E-DCH is a 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
E-DCH Basics
E DCH is a
modification of DCH
Not
a shared channel such as
E-DCH is amodification of DCH –
Not
a shared channel, such as
HSDPA in the downlink !!
PHY taken from R99 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 principlesp p
Intra Node B “softer” and Inter Node B “soft” HO should be supported for
the E-DCH with HARQ
E-DCH Scheduling
UE NodeB Scheduling information DATA UE detects data in buffer Scheduling information Scheduler takes UE for scheduling Scheduling grant UE sends scheduling information
MAC e signaling
Scheduling grant
Scheduling grant
MAC-e signaling
On E-DPCCH: “happy bit”
NodeB allocates the resources
Ab l t / l ti h d li t
Scheduling information Scheduling grant
Absolute/ relative scheduling grants
Algorithms left open from standards
Depending on the received grants, UE decides on transmission
ll d b f l
Maintains allocated resources by means of internal serving grants
Selects at each TTI amount of E-DCH data to transmit
E-DCH Scheduling Principle
E-DCH scheduler constraint
UL Load UL Load
Keep UL load within the limit Scheduler controls:
E-DCH load portion from
non-serving users of other cells
S i
UL Load target UE #m
serving users of other cells
E-DCH resources from each serving
user of own cell
Non E-DCH load portion
Serving E-DCH users
UE #1 Non E DCH load portion
DCH, RACH, HS-DPCCH
May include non-scheduled E-DCH
Controlled by legacy load control, Non-serving
E-DCH users
y g y ,
e.g. Admission/ Congestion control
Notes:
E-DCH users transmit
h l
Non E-DCH
asynchronously
UMTS Channels with E-DCH
C ll 1 C ll 2 Cell 1 UE UE Cell 2 = Serving E-DCH cellR99 DCH (in SHO)
UL/DL signalling (DCCH)
UL/DL CS voice/ data
Rel-6 E-DCH (in SHO)
UL PS service (DTCH)
UL/DL CS voice/ data
Rel-5 HS-DSCH (not shown)
DL PS service (DTCH)
DL signalling (Rel 6 DCCH)
UL PS service (DTCH) UL Signalling (DCCH)
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-DPDCH Contains the configuration as used on E DPDCH Fixed SF = 256
E RGCH/ E HICH
E-RGCH/ E-HICH
E-HICH carries the HARQ acknowledgements E-RGCH carries the relative scheduling grantsg g Fixed SF = 128
Up to 40 users multiplexed onto the same channel by using specific
signatures signatures
E-AGCH
Carries the absolute scheduling grants
d
Timing Relation (UL)
CFN+1 Downlink DPCH CFN Uplink DPCCH CFN 15 × Tslot (10 msec) 0.4 × Tslot (1024 chips) p E-DPDCH/ E DPCCH 10 msec ±148chips 10 msec TTI Subframe #0 E-DPCCH 3 × Tslot(2 msec)Subframe #1 Subframe #2 Subframe #3 Subframe #4 2msec TTI
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 msec 5772 2.89 Category 5 2 SF2 10 msec 20000 2.0 Category 6 4 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
When 4 codes are transmitted, 2 codes are transmitted with SF2 and 2 with SF4
(Rel.7) 2 msec 22996 11.5
, UE Category 7 supports 16QAM
E-DCH UTRAN Architecture
RRC PDCP
SRNC
Evolution from Rel-5
RLC
Logical Channels BCCH
DCCH DTCH
• E-DCH functionality is intended for transport of dedicated logical channels (DTCH/ DCCH) MAC-d DCH channels (DTCH/ DCCH) MAC-d flows MAC-es MAC-d flows E-DCH in Rel-6 • Additions in RRC to MAC-c/sh CRNC Upper phy o MAC-c/sh configure E-DCH • RLC unchanged
(UM & AM)
MAC-b NodeB MAC-hs w/ o MAC-e
• New MAC-es entity with link to MAC-d
• New MAC-e entity located
Transport Channels BCH DSCH FACH HS-DSCH EDCH in the Node B
• MAC-e entities from
multiple NodeB may serve UE ( ft HO)
MAC-e/es in UE
MAC-e/es Functions
Priority handling
Per logical channel
MAC-es/e MAC – Control To MAC-d Multiplexing E-TFC Selection Multiplexing
MAC-d flow concept
HARQ Multiplexing E-TFC Selection
Mux of data from multiple
MAC-d flows into single MAC-e PDU
Scheduling
Maintain scheduling grant
Associated Uplink Signalling: Associated Scheduling Downlink Signalling (E-AGCH / E-RGCH(s)) Associated ACK/NACK UL data (E-DPDCH) E-TFC selection HARQ handling
E-TFCI, RSN, happy bit (E-DPCCH) signaling
(E-HICH)
MAC-e in NodeB
MAC-e Functions Per user HARQ handling: MAC-d Flows ACK/ NACK generation De-multiplexing E DCH t l MAC Control UE #2 UE #N UE #1 E-DCH control: Rx/ Tx control signals MAC – Control De-multiplexing E-DCH Control E-DCH Scheduling UE #1E-DCH scheduling for all
users
Assign resources
HARQ entity
Assign resources
(scheduling grants)
Iub overload control
MAC-e E-DCH Cf. 25.309 Associated Downlink Signalling Associated Uplink Signalling Common RG
MAC-es in SRNC
To MAC-d MAC-es MAC C t l MAC-es Functions Queue distribution MAC – Control Disassembly Disassembly Reordering/ Combining Disassembly Reordering/ Combining Reordering/ Combining Reordering Per logical channel
Reordering Queue Distribution Reordering Queue Distribution Co b g Co b g Co b g In-sequence delivery Macro-diversity combining:
MAC-d flow #1 MAC-d flow #n
g frame selection Disassembly From From Disassembly MAC-e in NodeB #1 MAC-e in NodeB #k Cf. 25.309
Data Flow through Layer 2
RLC DATA Header DATA RLC PDU: MAC-d PDU: RLC MAC-d DDI: Data Description
Indicator (6bit)
MAC-d PDU size
DATA MAC d PDU:
MAC-e/es MAC-es PDU: TSN DATA DATA
Log. Channel ID
Mac-d flow ID
N N b f MAC d PDU
DDI N DDI N DDI DATA DATA Padding
N: Number of MAC-d PDUs
(6bit) TSN: Transmission Sequence MAC-es PDU MAC-e header (Opt) MAC-e PDU: Number (6bit) DATA PHY
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 retransmissionsy
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 ACK
ACK NACK
NACK
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
New Tx 1
NACK NACK
E-DCH UE Scheduling
UE maintains internal serving grant SG 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 of relative grants: increment/ decrement index of SG in the SG p g /
table
AG and RG from serving RLS can be activated for specific HARQ processes for
2msec TTIsec
UE selects E-TFC at each TTI
Allocates the E-TFC according to the given restrictions
S i t SG
Serving grant SG UE transmit power
Scheduling Grant Table
Index Scheduled Grant
37 (168/15)2*6
Scheduling grants are max.
E-DPDCH/ DPCCH power ratio (TPR –
t ffi t il t ti ) 37 (168/15)2*6 36 (150/15)2*6 35 (168/15)2*4 34 (150/15)2*4 33 (134/15)2*4 32 (119/15)2*4
traffic to pilot ratio)
Power Ratio is related to UE data
rate 32 (119/15)2*4 31 (150/15)2*2 30 (95/15)2*4 29 (168/15)2 • Relative Grants
SG moves up/ down when RG = UP/
DOWN • • 14 (30/15)2 13 (27/15)2 12 (24/15)2 11 (21/15)2 Absolute Grants
SG jumps to entry for AG
11 (21/15) 10 (19/15)2 9 (17/15)2 8 (15/15)2 7 (13/15)2 6 (12/15)2
2 reserved values for ZERO_GRANT/
INACTIVE 6 (12/15)2 5 (11/15)2 4 (9/15)2 3 (8/15)2 2 (7/15)2 2 1 (6/15)2 0 (5/15)2
Rate Scheduling Time Scheduling
E-DCH Scheduling Options
Rate Scheduling Time Scheduling
ate ate
ra ra
UE2
UE1
UE2 UE3 UE1
UE1
UE3
time time
UEs are continuously active
Data rate is incremental increased/
decreased by relative scheduling grants
N h b t UE i d
UEs are switched on/ off by absolute
scheduling grants
UEs should be in synch
L d i ti i ht b l
No synch between UEs required
Load variations can be kept low
For low to medium data rates
Load variations might be large (verry) high data rates
Timing Relation for Scheduling Grants
Scheduling
E-RGCH
E-AGCH HARQ process number decision Load estimation, etc 1 2 3 4 1 2 3 E-DCH • AG applied to this HARQ process • RG interpreted relative to the previous TTI in
AG and RG associated with specific uplink E-DCH TTI, i.e. specific HARQ process
Association based on the timing of the E AGCH and E RGCH
this HARQ process.
Association based on the timing of the E-AGCH and E-RGCH.
Timing is tight enough that this relationship is un-ambiguous.
Scheduling Information
Happy bit signaling
Happy bit signaling
One bit status flag send on E-DPCCH at each TTI
Criterion for happy bit
Criterion for happy bit
Set to “unhappy” if UE is able to send more data than given with
existing serving grant
O h
i
“h
”
Otherwise set to “happy”
Scheduling Information Reporting
Content of MAC-e report
Content of MAC 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)
HSUPA Resource Allocation
Node B resources -decoding capability
Cell resources
-Admissible uplink noise rise/load
Capabilities of the UEs -MAC-e PDU size limits
decoding capability
-Iub bandwidth capacity -CAC via RNCrise/load
-Number AGCH/RGCH
QoS parameters -Throughput bounds E-DCH Radio Resource Management “E-RRM”
-Keep uplink load within the limit -Control E-DCH load portion from
non-serving users of other cells MAC e PDU size limits
-SF limits
Throughput bounds
serving 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
-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 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
NodeB Scheduling Principle
E-DCH scheduler constraint
UL Load UL Load
Keep UL load within the limit
Scheduler controls:
E DCH load portion of non serving
S i
UL Load target UE #m
E-DCH load portion of non-serving
users from other cells
E-DCH resources of each serving user
of own cell Serving E-DCH users UE #1 of own cell Principles:
Rate vs. time scheduling
Non-serving E-DCH users
Dedicated control for serving users Common control for non-serving
users
Non E-DCH
Non-scheduled Mode
Configured by the SRNC
Configured by the SRNC
UE is allowed to send E-DCH data at any time
Signaling overhead and scheduling delay are minimized
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
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 scheduled MAC-d flow can only transmit up to the
non-scheduled grant configured for that MAC-d flow
Scheduled grants will be considered on top of non-scheduled
Sc edu ed g a ts be co s de ed o top o o sc edu ed
transmissions
Scheduled logical channels cannot use non-scheduled grant
Non scheduled logical channels cannot transmit data using Scheduling Grant Non-scheduled logical channels cannot transmit data using Scheduling Grant
E-DCH Operation in Soft Handover
scheduling grant scheduling grant UE UE scheduling grant HARQ ACK/ NACK scheduling grantHARQ ACK/ NACK
Macro diversity operation on multiple NodeBs NodeB 1
NodeB 1 NodeB 2NodeB 2
Macro-diversity operation on multiple NodeBs
Softer handover combining in the same NodeB Soft handover combining in RNC (part of MAC-es)
I d d MAC i i b h N d B
Independent MAC-e processing in both NodeBs
HARQ handling rule: if at least one NodeB tells ACK, then ACK Scheduling rule: relative grants “DOWN” from any NodeB have
d
Mobility Handling
The UE uses soft handover for associated DCH as well as for E DCH
The UE uses soft handover for associated DCH as well as for E-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 from only one cell out of the E-DCH
The UE receives AG on E AGCH from only one cell out of the E DCH
active set (serving E-DCH cell)
Rel-6: E-DCH and HSDPA serving cell must be the same
H d H d i h f i E DCH ll
Hard Handover, i.e. change of serving E-DCH cell
Using RRC procedures, which maybe triggered by event 1D
Mobility Procedures
SRNC SRNC
MAC-es MAC-es
MAC-e MAC-e MAC-e MAC-e NodeB NodeB NodeB NodeB
S i s t Serving E-DCH radio link Serving E-DCH radio link
Inter-Node B serving E-DCH cell change within E-DCH active set Note: MAC e still established in both NodeBs !
E-DCH State Transitions
Reuse of the DCH state transition framework 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
Transition to DCH
In case of handover to cells not supporting E-DCH Service specific triggers
Cell DCH HSDPA/ EDCH
Cell DCH HSDPA/ DCH
HSDPA/ EDCH HSDPA/ DCH
Cell FACH, URA_PCH, …
Cell DCH DCH/ DCH
E-DCH RRM Principle
E-DCH resources controlled by E-DCH resources controlled by
UL load target
Derived from RTWP target/ reference background noise
UL Load UL Load reference background noise
NodeB internal load target E-DCH non-serving load portion
Equivalent to target
non-S i
UL Load target
Equivalent to target non
serving E-DCH to total E-DCH power ratio
NodeB schedules E-DCH users di t RNC tti
Serving E-DCH users
according to RNC settings
Priority for non E-DCH traffic RNC still controls non E-DCH load portion
Non-serving E-DCH users
portion
By means of e.g. admission/ congestion control
Based on either of the following Non E-DCH
Non E-DCH load portion
Based on either of the following To be derived from RTWP OR Measure of non-EDCH load
E-DCH Performance & Capacity
E DCH offers improved throughput due to
E-DCH offers improved throughput due to
HARQ gain
Faster scheduling with tighter UL load control
Faster scheduling with tighter UL load control
The additional PHY channels consume resources
UL load: DPCCH, E-DPCCH
User Throughput vs. Aggregate Cell Throughput
36 cells network
1000 1200
10ms TTI, unlimited CE dec. rate 2ms TTI, next release 36 cells network
UMTS composite channel
model FTP t ffi d l (2 Mb t #UEs/cell 1 2 800 1000 p u t [k b p s ]
FTP traffic model (2 Mbyte
upload, 30 seconds thinking time) M i ll th h t 3 4 400 600 U s e r Th ro ug
h Maximum cell throughput
reached for about 7…8 UEs per cell
Cell throughput drops if #UEs
5 6 7 8 0 200 200 400 600 800 1000 1200 1400 1600
Cell throughput drops if #UEs increases further since the associated signaling channel consume UL resources too
8 9 10
200 400 600 800 1000 1200 1400 1600
Single User Performance
Average user throughput
(RLC layer) for different
2ms, 1Tx 10ms, 1Tx ( C aye ) o d e e
channel profiles
1 UE in the network
1 target HARQ transmission
3000 3500
, ,
g Q
For AWGN channel
conditions: 10ms TTI: up to 1.7 Mbps 2000 2500 ghput [ k bps ] p p
(near theoretical limit of 1.88 Mbps) 2ms TTI: up to 3 Mbps (b l th ti l li it 5 44 1000 1500 a ge U s e r Thr ou
(below theoretical limit 5.44 Mbps)
E.g. due to restrictions from RLC layer (window
0 500 Av er a y ( size, PDU size)
0
AW GN PedA3 PedA30 VehA30 VehA120
E-DCH Summary
New uplink transmission concept 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 channel: E-DCHp
Additional signalling channels to support HARQ and E-DCH scheduling MAC-e/es entity located in NodeB/ SRNC
Distributed E DCH scheduling between UE and NodeB Distributed E-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-use of principles for DCH control (handover state transition) Re use of principles for DCH control (handover, state transition) Significant improved performance
References
Papers 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 series: RAN Aspects TS 25.xxx series: RAN Aspects
TR 25.896: “Feasibility Study for Enhanced Uplink for UTRA FDD” TR 25.808: “FDD Enhanced Uplink; Physical Layer Aspects”p ; y y p
TR 25.309/ 25.319 (Rel.7 onwards): “(FDD) Enhanced Uplink: Overall
Abbreviations
ACK (positive) Acknowledgement AG Absolute Grant
AM Acknowledged (RLC) Mode AMC Adaptive Modulation & Coding
Mux Multiplexing
NACK Negative Acknowledgement NBAP NodeB Application Part
OVSF Orthogonal Variable SF (code) AMC Adaptive Modulation & Coding
BO Buffer Occupancy CAC Call Admission Control
CDMA Code Division Multiple Access DBC Dynamic Bearer Control
OVSF Orthogonal Variable SF (code) PDU Protocol Data Unit
PHY Physical Layer PO Power Offset QoS Quality of Service DBC Dynamic Bearer Control
DCH Dedicated Channel
DDI Data Description Indicator
DPCCH Dedicated Physical Control Channel E-AGCH E-DCH Absolute Grant Channel
Qo Qua y o
QPSK Quadrature Phase Shift Keying RB Radio Bearer
RG Relative Grant RL Radio Link E AGCH E DCH Absolute Grant Channel
E-DCH Enhanced (uplink) Dedicated Channel E-HICH E-DCH HARQ Acknowledgement Indicator Channel
E-RGCH E-DCH Relative Grant Channel
RLC Radio Link Control RLS Radio Link Set
RRC Radio Resource Control RRM Radio Resource Management E-TFC E-DCH Transport Format Combination
FDD Frequency Division Duplex FEC Forward Error Correction FIFO First In First Out
FP F i P t l
RV Redundancy Version SDU Service Data Unit SF Spreading Factor SG Serving Grant FP Framing Protocol
GoS Grade of Service
HARQ Hybrid Automatic Repeat Request IE Information Element
MAC d dedicated Medium Access Control
SI Scheduling Information TNL Transport Network Layer TPR Traffic to Pilot Ratio
TTI Transmission Time Interval UM U k l d d (RLC) M d MAC-d dedicated Medium Access Control