Dynamic Radio Bearer Control Feature Implementation Procedure and Algorithm
Content
Introduction
Related Measurement
R99 DRBC Algorithm
HSDPA DRBC Algorithm
HSUPA DRBC Algorithm
What is DRBC?
Dynamic Radio Bearer Control (DRBC) is used to allocate resource efficiently to make full use of it in system running state, according to subscriber requirement and system resource utilization.
How DRBC works?
Parameter DRBC Switch(DrbcSwch) is used to start or stop service dynamic rate and channel switching algorithm. If DrbcSwch is ON, the function works, including initial
channel allocation, rate and channel switching and so on.
If DrbcSwch is OFF, after initial rate and channel for service is allocated, it will never happen switching before service release.
Initial Channel Allocation
Initial channel allocation is related to cell and UE capability, service type and rate.
Rate and Channel Switching
Connected Mode
Idle Mode
CELL_DCH
CELL_FACH
URA_PCH
PCH
DL FACH/ UL RACH
DL HS-DSCH/ UL DCH <-> DL DCH/UL DCH
DL HS-DSCH/ UL E-DCH <-> DL DCH/ UL DCH
DL DCH/ UL DCH -> DL DCH/UL DCH(UL/DL Decrease or Increase Rate)
Content
Introduction
Related Measurement
R99 DRBC Algorithm
HSDPA DRBC Algorithm
HSUPA DRBC Algorithm
Channel Switching
Content
Introduction
Related Measurement
R99 DRBC Algorithm
HSDPA DRBC Algorithm
HSUPA DRBC Algorithm
Initial Channel Allocation - Signaling
The rate and transport channel for signaling of RRC connection can be set through parameter “InitRrcOnDch”: Forced to DCH and Using Normal Speed Signaling Forced to DCH and Using High Speed Signaling (default) Forced to FACH Not Forced, Using Normal Speed Signaling on Cell-DCH
State Not Forced, Using High Speed Signaling on Cell-DCH State
Initial Channel Allocation - Service
FACHFACHDCHDCH
ConversationConversation StreamingStreaming Interactive &Interactive & BackgroundBackground
DL MaxBR >= DL MaxBR >= Rfach Rfach or or
UL MaxBR >= UL MaxBR >= RrachRrach
Y N
Initial Rate Calculation If the DRBC switch DrbcSwch is set to OFF,
the DCH initial rate = min(max (highest rate level of DBRC, GBR), MaxBR).
If the DRBC switch DrbcSwch is ON,
the DCH initial rate = min (max (min (lowest rate level of DBRC, DCH rate limitation), GBR), MaxBR).
The uplink and downlink DRBC rate levels are configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST] DlRateAdjLev[MAX_NUM_RATE_ADJUST].
The DCH rate limitation:
NRT servive of uplink DCH rate limitation is NrtMaxUlRateDch, downlink DCH rate limitation is NrtMaxDlRateDch;
RT service of uplink DCH rate limitation is RtMaxUlRateDch, downlink DCH rate limitation is RtMaxDlRateDch.
Initial Channel Allocation - Concurrent Service
DCHDCHDCHDCH
FACHFACH
New service Requires DCHNew service Requires DCH
New service Requires FACHNew service Requires FACH
FACHFACH
FACHFACH
New serviceNew service
Current serviceCurrent service
Initial Channel Allocation - Concurrent ServiceNew service established
Current service in Cell-DCH state
New service establish on
Cell-DCH stateCell-FACH→ Cell-DCH Cell-FACH state
Finish
New service type?
New service requires to establish on
Cell-DCH
New service requires to establish on
Cell-FACHY
N
Concurrent Service Rate Calculation The calculation is similar as only single service.
For concurrent CS and PS(S/I/B) services, If DrbcSwch is OFF, the DCH rate is:
min(max (highest rate level of DRBC, GBR), MaxBR)
If DrbcSwch is ON, the DCH rate is:
min( max( min(lowest rate level of DRBC, DCH rate limitiation), GBR), MaxBR)
R99 Channel Switching
CELL-DCH
DCH/DCH
CELL-FACH
FACH/RACH
URA_PCH
PCHIdle
Reconfigure SF1. UL/DL Traffic Volume Based2. DL D-TCP Based3. UL TxP Based4. Cell’s RTWP5. Cell’s TCP
UL DCH/DL DCH -> UL RACH/DL FACH1. UL&DL Traffic Volume Based2. Support Cell_FACH
UL RACH/DL FACH -> UL DCH/DL DCH1. UL/DL Traffic Volume Based2. Cell’s RTWP & Cell’s TCP
UL DCH/DL DCH -> PCH1. UL&DL Traffic Volume Based2. Support PCH switching
UL RACH/DL FACH -> IDLEUL&DL Traffic Volume Based
UL DCH/DL DCH ->IDLEUL&DL Traffic Volume Based
PCH->IDLEDL&UL Traffic Volume Based
UL RACH/DL FACH -> PCH1. UL&DL Traffic Volume Based2. Support PCH switching
PCH -> UL RACH/DL FACHUL/DL Traffic Volume based
Traffic Related Events Event 4A
triggered when measured traffic value exceeds an absolute threshold which is related to DCH increasing rate
Event 4B triggered when measured traffic value is smaller than
an absolute threshold which is related to DCH decreasing rate
Event 4B0 triggered when measured traffic value is 0. 4B0 event
is an special case of 4B.
Time to Trigger and Pending Time
Traffic Volume
4A Threshold
Time to Trigger
PendingTime
PendingTimeTime to
TriggerTime to Trigger
Report 4A Report 4A Report 4A Time
Time to Trigger and Pending Time are used to prevent triggering too frequently.Pending Time is a time for shielding in the same event reporting.
UL TxP Related Events Event 6A1, 6B1
used for UL decreasing rate when 6A1 is reported, UE is considered as a high
transmitted power status, and the uplink rate can be decreased.
when 6B1 is reported, UE is not in a high transmitted power status, and UL decreasing rate will be stopped.
Event 6A2, 6B2 used to check whether UE TxP is in a low level when 6B2 is reported, UE is considered as a low
transmitted power status, and the UL rate can be increased.
when 6A2 is reported, UE is not in a low transmitted power status, and UL increasing rate will stopped.
UL TxP Related Events
UE TxP
Time
Thr_6A1
Thr_6A2
Thr_6B1
Thr_6B2
Reporting Event 6A1
Reporting Event 6B1
Reporting Event 6A2
Reporting Event 6B2
In this example, Time To Trigger=0
DL D-TCP Related Events DL D-TCP stands for downlink Transmitted Carrier
Power for dedicated channel of single UE, which is measured by NodeB. It acts as one of the factors to trigger decreasing rate. Meanwhile, it is also a restriction for increasing rate.
Event A and B If the DL D-TCP measurement value is larger than a
upper threshold, event A will be triggered. Rate will be decreased, the DL D-TCP for the UE is considered as a high transmitted power status.
Otherwise the DL D-TCP for the UE is considered as a low transmitted power status.
DL D-TCP Related Events
upper_threshold
lower_threshold
DL D-TCP
Time
Event B
In this example, Time To Trigger=0
Event A Event B
Content
Introduction
Related Measurement
R99 DRBC Algorithm
HSDPA DRBC Algorithm
HSUPA DRBC Algorithm
HSDPA Initial Channel Allocation - Signaling The rate and transport channel for signaling of RRC
connection is the same as the R99. For the setup of RAB, the signaling channel is
selected by the following principles: The low-speed bearer signaling DL DCH/UL DCH is
selected if there is DL DCH/UL DCH bearer service. All services are on the DL HS-DSCH/UL DCH. If both
UTRAN and UE support F-DPCH, the signaling is on the DL HS-DSCH/UL DCH. Otherwise, the signaling is mapped to DCH/DCH low rate signaling.
Initial Channel Allocation - Service
FACHFACH
DCHDCH HS-DSCHHS-DSCH
ConversationalConversational streamingstreaming I/BI/B
12
31
2
Initial Channel Allocation - Concurrent Service
DCHDCH
HS-DSCHHS-DSCH
FACHFACH
I/B+I/B
All services use same channel typeAll services use same channel type
I/B+S or S+SI/B+S or S+S
All services use same channel typeAll services use same channel type
Initial Channel Allocation - Concurrent Service
DCHDCH
HS-DSCHHS-DSCH
C+I/BC+I/BDifferent services go to different channelDifferent services go to different channel
I/B+C or S+C or I/B+S+CI/B+C or S+C or I/B+S+C
Different services go to different channelDifferent services go to different channel
CC
S/I/BS/I/B
CC
I/BI/B
HSDPA Channel Switching
CELL_DCH
HS-DSCH/DCHDCH/DCH
CELL_FACH
RACH/FACH
URA_PCH
PCHIdle
Reconfig SF1. UL/DL Traffic Volume Based2. DL D-TCP Based3. UL TxP Based4. Cell’ s RTWP5. Cell’ s TCP
Transition of DCH/DCH -> FACH/RACH1. UL&DL Traffic Volume Based
2. Support CELL_FACH
Transition of HS-DSCH/DCH -> FACH/RACH1. UL&DL Traffic Volume Based
2. Support CELL_FACH
Transition of FACH/RACH -> DCH/DCH1. UL/DL Traffic Volume Based2. Cell’ s RTWP & Cell’ s TCP
Transition of FACH/RACH -> HS-DSCH/DCH1. UL/DL Traffic Volume Based
2. UE &Cell Capability3. Cell’ s RTWP & Cell’ s TCP
Transition of DCH/DCH -> PCH1. UL&DL Traffic Volume Based2. Support PCH
Transition of HS-DSCH/DCH -> PCH1. UL&DL Traffic Volume Based2. Support PCH
Transition DL DCH -> DL HS-DSCH1. DL Traffic Volume Based2. Channel Quality Measure Based (Option)3. UE &Cell Capability
Transition DL HS-DSCH -> DL DCH1. Channel Quality Measure Based (Option)
Transition of FACH/RACH -> IDLE1. UL&DL Traffic volume Based
Transition of DCH/DCH -> IDLE1. UL&DL Traffic Volume Based
Transition of HS-DSCH/DCH -> IDLE1. UL&DL Traffic Volume Based
Transition of PCH->IDLE1. DL&UL Traffic Volume Based
Transition of FACH/RACH -> PCH1. UL&DL Traffic Volume Based2. Support PCH
Transition of PCH -> FACH/RACH1. UL/DL Traffic Volume Based
Measurement and Events Based on downlink channel quality
1F event: DL HS-DSCH -> DL DCH 1E event & traffic volume E4A: DCH-> HS-DSCH
Mobility-based channel switching the source cell supports HSDPA, but the target cell
only supports R99
Measurement and Events HSDPA support :
CELL_DCH(DL HS-DSCH/UL DCH)<->CELL_FACH switching triggered by traffic (dual directions)
CELL_DCH (DL HS-DSCH)<->DL DCH Triggered by traffic DCH->HS-DSCH Triggered by pilot channel quality HS-DSCH->DCH Switching triggered by mobility (dual directions)
CELL_DCH (DL HS-DSCH/UL DCH)<->URA_PCH CELL_DCH (DL HS-DSCH/UL DCH)->IDLE
Pilot Channel Quality Measurement The channel quality measurement is for the switching from
HS-DSCH to DCH. The Event 1E and Event 1F are used. The channel quality measurement CQ is performed on
P-CPICH. If the UE supports HS-DSCH, or ,UE are using DCH and the best cell in active set support HS-DSCH, the measurement is initiated.
Spectrum efficiency
CQ
DCH
HS-DSCH
1F threshold 1E threshold
Pilot Channel Quality Measurement 1E event : when the pilot signaling quality is larger than an
absolute threshold (ThreshUsedFreq) and this condition lasts for a moment (TrigTime), event 1E will be reported.
1F event : when the pilot signaling quality is lower than an absolute threshold (ThreshUsedFreq) and this condition lasts for a moment (TrigTime), event 1F will be reported.
1E event
Absolute threshold
Reporting event 1E
Measurement quantity
Time
P CPICH 1
P CPICH 2
P CPICH 3
1F event
Absolute threshold
Reporting event 1F
Measurement quantity
Time
P CPICH 1
P CPICH 2
P CPICH 3
Content
Introduction
Related Measurement
R99 DRBC Algorithm
HSDPA DRBC Algorithm
HSUPA DRBC Algorithm
Initial Channel Allocation - Signaling The signaling channel allocation process upon the RRC
connection setup is the same as the R99 policy. For the setup of RAB allocation service, the signaling channel
switching complies with the following principles: The low-speed bearer signaling DL DCH/UL DCH is
selected if there is DL DCH/UL DCH bearer service. If all the services are on the DL HS-DSCH/UL DCH: If both
the system and UE support F-DPCH, the signaling is on the DL HS-DSCH/UL DCH; otherwise, the signaling is mapped to DCH/DCH low rate signaling.
If all the services are on the DL HS-DSCH/UL E-DCH: If both the system and UE support F-DPCH, the signaling is on the DL HS-DSCH/UL E-DCH; otherwise, the signaling is mapped to DCH/DCH low rate signaling.
Initial Channel Allocation - Service
FACHFACH
DL DCH/UL DCHDL DCH/UL DCH DL HS-DSCH/DL HS-DSCH/
UL E-DCHUL E-DCH
conversationalconversational streamingstreaming I/BI/B
12
4
1
2
DL HS-DSCH/DL HS-DSCH/
UL DCHUL DCH
3
3
Initial Channel Allocation - Concurrent Service
DCHDCH
FACHFACH
I/B+I/BI/B+I/BAll services use same channel typeAll services use same channel type
I/B+S I/B+S
OR OR
S+SS+S
All services use same channel typeAll services use same channel type
DL HS-DSCH/DL HS-DSCH/
UL E-DCHUL E-DCH
DL HS-DSCH/DL HS-DSCH/
UL DCHUL DCH
Initial Channel Allocation - Concurrent Service
DCHDCH
C+I/BC+I/B
Different services go to different channelDifferent services go to different channel
I/B+CS or S+CS or
I/B+S+CS
Different services go to different channelDifferent services go to different channel
CC
I/B/SI/B/S
I/BI/B
CC
DL HS-DSCH/DL HS-DSCH/
UL E-DCHUL E-DCH
DL HS-DSCH/DL HS-DSCH/
UL DCHUL DCH
HSUPA Channel Switching
CELL_DCH
DCH/DCHCELL_FACH
RACH/FACH
URA_PCH
PCHIdle
Reconfig SF1. UL/DL Traffic Volume Based2. DL D-TCP Based3. UL TxP Based4. Cell’ s RTWP5. Cell’ s TCP
Transition of DCH/DCH -> FACH/RACH1. UL&DL Traffic Volume Based2. Support CELL_FACH
Transition of HS-DSCH/DCH -> FACH/RACH1. UL&DL Traffic Volume Based2. Support CELL_FACH
Transition of HS-DSCH/E-DCH -> FACH/RACH1. UL&DL Traffic Volume Based2. Support CELL_FACH
Transition of FACH/RACH -> DCH/DCH1. UL/DL Traffic Volume Based2. Cell’ s RTWP & Cell’ s TCP
Transition of FACH/RACH -> HS-DSCH/DCH1. UL/DL Traffic Volume Based2. UE &Cell capability3. Cell’ s RTWP & Cell’ s TCP
Transition of FACH/RACH -> HS-DSCH/E-DCH1. UL/DL Traffic Volume Based2. UE &Cell capability3. Cell’ s RTWP & Cell’ s TCP
Transition of DCH/DCH -> PCH1. UL&DL Traffic Volume based2. Support PCH
Transition of HS-DSCH/DCH -> PCH1. UL&DL Traffic Volume based2. Support PCH
Transition of HS-DSCH/E-DCH -> PCH1. UL&DL Traffic Volume Based2. Support PCH
Transition DCH/DCH -> HS-DSCH/E-DCH1. UL/DL Traffic Volume Based2. Channel Quality Measure Based (Option)3. UE &Cell Capability4. Compressed Mode is not started
Transition DCH/DCH -> HS-DSCH/DCH1. UL/DL Traffic Volume Based2. Channel Quality Measure Based (Option)3. UE &Cell Capability
Transition HS-DSCH/E-DCH -> DCH/DCH1. Channel Quality Measure Based (Option)
Transition HS-DSCH/DCH -> DCH/DCH1. Channel Quality Measure Based (Option)
Transition HS-DSCH/DCH -> HS-DSCH/E-DCH1. UL Traffic Volume Based2. UE &Cell Capability3. If HSUPA associate compressed mode method is set to “ Serial” , the compressed mode is not started
Transition of FACH/RACH -> IDLE1. UL&DL Traffic Volume Based
Transition of DCH/DCH ->IDLE1. UL&DL Traffic Volume Based
Transition of HS-DSCH/DCH -> IDLE1. UL&DL Traffic Volume Based
Transition of HS-DSCH/E-DCH -> IDLE1. UL&DL Traffic Volume Based
Transition of PCH->IDLE1. DL&UL Traffic Volume Based
Transition of FACH/RACH -> PCH1. UL&DL Traffic Volume Based2. Support PCH
Transition of PCH -> FACH/RACH1. UL/DL Traffic Volume Based
HS-DSCH /E-DCH or
HS-DSCH/DCH
Measurement and Events HSUPA support :
CELL_DCH(DL HS-DSCH/UL E-DCH)<->CELL_FACH—triggered by traffic(dual directions)
CELL_DCH (DL HS-DSCH/UL E-DCH)<->CELL_DCH(DL DCH/UL DCH)
triggered by traffic - DL DCH/UL DCH->DL HS-DSCH/UL E-DCH
triggered by signal quality DL HS-DSCH/UL E-DCH->DL DCH/UL DCH
triggered by mobility DL HS-DSCH/UL E-DCH<->DL DCH/UL DCH or DL HS-DSCH/UL DCH
CELL_DCH (DL HS-DSCH/UL E-DCH)<->URA_PCH CELL_DCH (DL HS-DSCH/UL E-DCH)->IDLE
Configuration Parameter
Configuration Parameter
DRBC Procedure
1F event DchE4bThd
FToPchThd
PchHoldTimeThr 600s
FToIdleThd
Time to trigger for 4b=2560ms
Pending Time=16000ms
By default, PCH Channel is not enabled
Cell_FACHCell_FACH
Time to trigger for 4b=2560ms
Pending Time=16000ms
Cell_DCH/Cell_DCH/HS-DSCH
HsToFtimesThr
HS-DSCH/EHS-DSCH/E
DToIdleThd
UP 4B&UE 4BUP 4B&UE 4B
UP 4B0&UE 4B0UP 4B0&UE 4B0
DToIdleThd
UP 4B0&UE 4B0UP 4B0&UE 4B0
UP 4B0&UE 4B0UP 4B0&UE 4B0