More Related Content
Similar to LTE1406 Extended VoLTE Talk Time.pptx
Similar to LTE1406 Extended VoLTE Talk Time.pptx (20)
LTE1406 Extended VoLTE Talk Time.pptx
- 1. 25/05/2023
1 © Nokia 2014
Customer Confidential
Extended VoLTE Talk Time
LTE1406
NPO Feature Training
FDD-LTE 15
- 2. 25/05/2023
2 © Nokia 2014
For internal use
Revision – DRX for VoLTE (I)
• An expected benefit of VoIP when compared to CS speech over 2G or 3G is improved
battery life
• achieved by allowing the UE to ‘sleep’ between packet transmissions
• DRX patterns are used to define the ‘sleep’ pattern
• DRX profile 2 has been optimised for the VoIP service
Parameter Default
drxProfileIndex 2
drxInactivityT 4 subframes
drxLongCycle 40 ms
drxOnDuratT 6 subframes
DrxProfilePriority 40
drxRetransT 4
Allows increased periods of sleep &
reduces PDCCH load relative to 20 ms
Relatively low value to avoid long re-
transmission delays and to help
maximise sleep periods
Short inactivity timer to allow UE to return to
sleep after each packet transmission
- 3. 25/05/2023
3 © Nokia 2014
For internal use
Revision – DRX for VoLTE (II)
• Measurements from Nokia Smartlabs have illustrated the impact of DRX upon UE
battery power consumption
129 125
235
154
131
121
248
4%
0%
88%
24%
5%
-3%
99%
-20%
0%
20%
40%
60%
80%
100%
0
50
100
150
200
250
300
3G CS
AMR-NB
3G CS AMR-
WB
noDRX DRX
20ms
6ms OnDur
DRX
40ms
6ms OnDur
DRX
40ms
4ms OnDur
Viber
Current
(mA)
Current [mA] Gain
DRX
Set1
DRX
Set2
DRX
Set3
- 4. 25/05/2023
4 © Nokia 2014
For internal use
Revision – DRX in Downlink
• Downlink packets can be sent during DRX active periods when UE wakes from sleep
• 40ms DRX cycle leads to packet aggregation and increased sleep periods
20ms
DL
Grant
+
DL
data
DRX Active
DRX Sleep
20ms
DL
Grant
+
DL
data
DRX long cycle = 40ms
- 5. 25/05/2023
5 © Nokia 2014
For internal use
Revision – DRX in Uplink
• UE have specific subframes during which they are permitted to send Scheduling Requests
• may not be aligned with the normal DRX active periods
• triggers additional DRX active periods and increases UE power consumption
20ms
DRX Active
DRX Sleep
20ms
Sched.
Req.
DRX long cycle = 40ms
UL
Trans.
UL
Alloc.
Sched.
Req.
UL
Trans.
UL
Alloc.
- 6. 25/05/2023
6 © Nokia 2014
For internal use
Revision – DRX in Uplink & Downlink
• Downlink packets will be transferred during the first available DRX active period
• Relatively frequent DRX active periods when Scheduling Request does not coincide with
normal DRX active period
DRX Active
DRX Sleep
Sched.
Req.
DRX long cycle = 40ms
UL
Trans.
UL
Alloc.
20ms 20ms
DL
Grant
+
DL
data
Sched.
Req.
UL
+
DL
Trans.
UL
+
DL
Alloc.
DL
Grant
+
DL
data
DL
Grant
+
DL
data
- 7. 25/05/2023
7 © Nokia 2014
For internal use
Revision – Impact of Re-transmissions
• Downlink packets will be transferred during the first available DRX active period
• Relatively frequent DRX active periods when Scheduling Request does not coincide with
normal DRX active period
DRX Active
DRX Sleep
Sched.
Req.
UL
Trans.
UL
Alloc.
20ms 20ms
DL
Grant
+
DL
data
Sched.
Req.
UL
+
DL
Trans.
UL
+
DL
Alloc.
DL
Grant
+
DL
data
DL
Grant
+
DL
data
UE monitors the PDCCH for re-transmissions
- 8. 25/05/2023
8 © Nokia 2014
For internal use
Extended VoLTE Talk Time (eVTT) - Requirements
• System Release FDD-LTE 15
• Flexi Release 2 LN7.0
• Flexi Release 3 LN7.0
• This feature does not require any additional hardware
• The following must be enabled as a prerequsite:
• VoLTE feature set
• DRX or SmartDRX
• The UE must support the Feature Groups Indicators (FGI) on the following slide
• This feature is Application Software (ASW)
- 9. 25/05/2023
9 © Nokia 2014
For internal use
UE Requirements
• The following Feature Group Indicators (FGI) are checked to verify that the UE
supports eVTT functionality
• bit 3 (5 bit RLC UM SN, 7 bit PDCP SN)
• bit 5 (Long DRX cycle)
• bit 7 (RLC UM)
• Bits 3 and 7 are pre-requisites for VoIP
- 10. 25/05/2023
10 © Nokia 2014
For internal use
Activating the Feature
• The feature is enabled using the actQci1eVTT parameter
• This parameter is online so does not require object locking for modification
Name Range Default Description
actQci1eVTT
(LNCEL)
0 (false), 1 (true) 0 (false) Activates the feature 'Extended VoLTE talk time'
• If actQci1eVTT = 'true' then:
• actDrx or actSmartDrx must equal 'true‘
• qci1eVTTConfig must be configured
• drxSmartProfile2 - drxLongCycle must be equal to drxSmartProfile2 -
drxShortCycle
- 11. 25/05/2023
11 © Nokia 2014
For internal use
Enhancements
1. Alignment of Scheduling Request (SR) timing with DRX ‘ON’ timing
2. Adjustment of SR periodicity to DRX Long Cycle length
3. Dedicated BLER Target and number of HARQ Re-transmissions for VoLTE
4. SRS and Secondary Cell Deactivation
• further reduces UE battery power consumption
Help to
reduce DRX
active time
• Enhancement 1 is generally available with RL70 and does not require
LTE1406 eVTT to be enabled
- 13. 25/05/2023
13 © Nokia 2014
For internal use
Target Scenario – Timing Offset (High Level)
• Scheduling Request timing is configured such that both uplink and downlink:
• use packet aggregation
• transfer data during the normal DRX active periods
DRX Active
DRX Sleep
20ms 20ms
Sched.
Req.
UL
+
DL
Trans.
UL
+
DL
Alloc.
DL
Grant
+
DL
data
Sched.
Req.
UL
+
DL
Trans.
UL
+
DL
Alloc.
DL
Grant
+
DL
data
- 14. 25/05/2023
14 © Nokia 2014
For internal use
Target Scenario – Timing Offset (Detailed)
DRX Long Cycle = 40 ms
DRX Active
DRX Sleep
Beginning of a
DRX Cycle
Beginning of a
DRX Cycle
CQI
SR CQI
UL Data
UL
Grant
SR
• The Scheduling Request timing is configured such that a Scheduling Request can be
sent 3 TTI prior to the periodic CQI
- Uplink Grant on the PDCCH can be provided at earliest 1 ms after the periodic CQI
• Scheduling Request + 4 ms
- 15. 25/05/2023
15 © Nokia 2014
For internal use
Target Scenario – Scheduling Request Period
• The Scheduling Request period is adjusted to equal the DRX long cycle duration
- with default setting of drxProfile2: drxLongCycle, the Scheduling Request periodicity
will be set to 40ms
SR
SR
SR
SR period =
20ms
SR period =
20ms
SR
SR
SR period =
40ms
Without LTE1406
With LTE1406
DRX Active
DRX Sleep
DRX Active
DRX Sleep
- 16. 25/05/2023
16 © Nokia 2014
For internal use
Scheduling Request Configuration
• The UE is provided
with Scheduling
Request information
during connection
establishment
• Scheduling Request
Configuration Index
defines both:
• periodicity
• timing offset
• eNode B determines
the Configuration
Index for each UE
- 18. 25/05/2023
18 © Nokia 2014
For internal use
Maximum number of HARQ Re-transmissions
• A further reduction of a PDCCH monitoring periods can be achieved by using a lower
number of allowed HARQ retransmissions
- 3GPP specifies that a UE must be in DRX Active state when an uplink grant for a
pending HARQ retransmission can occur
• this means that a UE will read the PDCCH (harqMaxTrUl -1) times after initial
transmission, using 8ms intervals even if successful Transport Block reception has
been confirmed by ACK
• depending upon UE implementation, the UE may not enter the sleep state between
PDCCH readings
DRX Active
DRX Sleep
UE must monitor PDCCH due to HARQ retransmissions
ACK
UL
Grant
UL
Data
- 19. 25/05/2023
19 © Nokia 2014
For internal use
BLER Target
• When using a reduced number of allowed HARQ retransmissions it is important to select
an appropriate MCS for VoIP packet transmission
- reduced uplink and downlink BLER targets can be used to compensate
- the reduced BLER target means that Link Adaptation adjusts the MCS more rapidly
- 20. 25/05/2023
20 © Nokia 2014
For internal use
Enhanced VoLTE Talk Time (eVTT) Profile
• Profile allows the allocation of VoLTE specific parameters:
• Maximum number of uplink and downlink HARQ re-transmissions
• BLER Target
• These VoLTE specific parameters are applied to QCI 1 bearers if the following 2 conditions
are satisfied:
qci1DlTargetBler
qci1UlTargetBler
qci1HarqMaxTrDl
qci1HarqMaxTrUl
qci1ReconStopTimer
qci1ThroughputFactorDl
qci1ThroughputFactorUl
qci1eVTTConfig
UE DL Throughput < qci1ThroughputFactorDl × GBR DL
and
UE UL Throughput < qci1ThroughputFactorUl × GBR UL
• High throughputs indicate that connection is being used for
data, in addition to VoIP
- 21. 25/05/2023
21 © Nokia 2014
For internal use
eVTT Parameters (I)
• The default throughput factors are 1.6
• used to determine whether or not the eVTT parameters are applied
Name Range Default Description
qci1ThroughputFactorDl
(LNCEL)
1 to 4,
step 0.2
1.6 Multiplication factor for the QCI1 traffic (based on
GBR) to achieve the qci1MaxThroughputDl.
Name Range Default Description
qci1ThroughputFactorUl
(LNCEL)
1 to 4,
step 0.2
1.6 Multiplication factor for the QCI1 traffic (based on
GBR) to achieve the qci1MaxThroughputUl.
- 22. 25/05/2023
22 © Nokia 2014
For internal use
eVTT Parameters (II)
• Default values for uplink and downlink BLER targets are the same as those for the
normal BLER targets defined by:
• dlTargetBler
• ulTargetBler
Name Range Default Description
qci1DlTargetBler
(LNCEL)
2 to 20 %,
step 0.1 %
10 % Dedicated BLER target for DL LA in % for QCI1.
Name Range Default Description
qci1UlTargetBler
(LNCEL)
2 to 20 %,
step 0.1 %
10 % Dedicated Target BLER for AMC UL for QCI1
- 23. 25/05/2023
23 © Nokia 2014
For internal use
eVTT Parameters (III)
• Default values for the maximum number of re-transmissions are similar to the
normal values defined by:
• harqMaxTrDl = 4
• harqMaxTrUl = 5
Name Range Default Description
qci1HarqMaxTrU
l
(LNCEL)
1 to 7, step
1
5 Indicates the dedicated Maximum number of HARQ
transmission for QCI1 in UL, which is configured for
each UE when in RRC_Connect mode in the cell.
Name Range Default Description
qci1HarqMaxTrD
l
(LNCEL)
1 to 16,
step 1
5 Indicates the dedicated Maximum number of HARQ
transmission for QCI1 in DL, when in RRC_Connect
mode in the cell.
- 24. 25/05/2023
24 © Nokia 2014
For internal use
eVTT Parameters (IV)
• Guard timer (qci1ReconfStop) to avoid ping-pong between standard and eVTT configurations
• Throughput variations can cause reconfigurations to be triggered
• Timer is started after a reconfiguration
• subsequent reconfiguration not permitted until timer expires
• Timer is first used when UE is reconfigured from the eVTT configuration to the standard
configuration
Name Range Default Description
qci1ReconStopTimer
(LNCEL)
1 to 5,
step 0.2
secs
1 sec Dedicated HARQ and BLER reconfiguration timer
for QCI1. When this timer expires UL-S and/or
DL-S are entitled to perform a reconfiguration of
HARQ and BLER parameters if throughput
measures of the UE are such that require they
reconfiguration.
- 25. 25/05/2023
25 © Nokia 2014
For internal use
Maximum number of Reconfigurations
• The maximum permitted number of reconfigurations is hardcoded to 3
• If multiple reconfigurations are triggered then the UE is left with the standard
configuration
• The 3 permitted reconfigurations are:
• eVTT -> standard
• standard -> eVTT
• eVTT -> standard
- 26. 25/05/2023
26 © Nokia 2014
For internal use
Leaving Conditions
• UE are reconfigured back to the standard configuration when any of the following are
satisfied:
• the uplink or downlink throughput increases above the original triggering
threshold
• when the QCI 1 bearer is released
• when EDG (Emergency Downgrade) event is triggered, AND
• if E-ULA is activated, MCS4 with 3 PRBs was used, OR
• if F-ULA is activated:
• If actModulationSchemeUL = QPSK:
• OLLACF = -7
• If actModulationSchemeUL = 16QAM/16QAMHighMCS
• OLLACF = -15
- 28. 25/05/2023
28 © Nokia 2014
For internal use
Secondary Cell and Sounding Reference Signal (SRS)
• Secondary cells and the SRS are removed from the UE’s connection whenever
the eVTT configuration is applied
• Both can be added back to the connection when the standard configuration is
re-applied
- 30. 25/05/2023
30 © Nokia 2014
For internal use
Counters
• There are no new counters introduced with this feature
Editor's Notes
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
- NR abbreviation
