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NR Idle mode overview
Ref: TS 38.304 V16.3.0 (2020-12)
ICL/M100
Lin, Jung-Mao
1
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RRC states in NR
RRC states in NR
2
UE NG-RAN 5GCSuspend Connected
RRC_INACTIVE
UE NG-RAN 5GCConnected Connected
RRC_CONNECTED(5G Core Network)
UE NG-RAN 5GCReleased Released
RRC_IDLE
For power saving
For power saving and speed up connection setup
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Outline
Cell selection/reselection procedure
General description
Cell Categories
Cell selection/reselection procedure
Paging
Principles
Beam sweeping
DRX
Paging Reception
3
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CELL SELECTION/RESELECTION PROCEDURE
General description
4
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General descriptionThe RRC_IDLE state and RRC_INACTIVE state tasks can be subdivided into three processes:
5
•When a UE is switched on, a public land mobile network (PLMN) or a Stand-alone Non-Public Network (SNPN) is selected by NAS.
•The NAS shall provide a list of equivalent PLMNs, if available, that the AS shall use for cell selection and cell reselection.
PLMN selection
•With cell selection, the UE searches for a suitable cell of the selected PLMN or selected SNPN, chooses that cell to provide available services, and monitors its control channel. This procedure is defined as "camping on the cell".
• If the UE finds a more suitable cell, according to the cell reselection criteria, it reselects onto that cell and camps on it.
Cell selection and reselection
• If the new cell does not belong to at least one tracking area to which the UE is registered, location registration is performed.
• In RRC_INACTIVE state, if the new cell does not belong to the configured RNA, an RNA update procedure is performed
Location registration and RNA update
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General descriptionThe purpose of camping on a cell in RRC_IDLE state and RRC_INACTIVE state is fourfold:
a) It enables the UE to receive system information from the PLMN or the SNPN.
b) When registered and if the UE wishes to establish an RRC connection or resume a suspended RRC connection, it can do this by initially accessing the network on the control channel of the cell on which it is camped.
c) If the network needs to send a message or deliver data to the registered UE, it knows (in most cases) the set of tracking areas (in RRC_IDLE state) or RNA (in RRC_INACTIVE state) in which the UE is camped.
It can then send a "paging" message for the UE on the control channels of all the cells in the corresponding set of areas.
The UE will then receive the paging message and can respond.
d) It enables the UE to receive ETWS and CMAS notifications.
6
ETWS: Earthquake and Tsunami Warning SystemCMAS: Commercial Mobile Alert System
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CELL SELECTION/RESELECTION PROCEDURE
Cell Categories
7
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Cell CategoriesAcceptable cell:
An “acceptable cell” is a cell on which the UE may camp to obtain limited service (originate emergency calls and receive ETWS and CMAS notifications).
Such a cell shall fulfil the following requirements, which is the minimum set of requirements to initiate an emergency call and to receive ETWS and CMAS notification in an NR network:
The cell is not barred
The cell selection criteria are fulfilled
barred cell:
A cell a UE is not allowed to camp on.
A cell is barred if it is so indicated in the system information
reserved cell:
A cell on which camping is not allowed, except for particular UEs, if so indicated in the system information.
A cell is reserved if it is so indicated in system information
8
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Cell Categoriessuitable cell:
For UE not operating in SNPN Access Mode, a cell is considered as suitable if the following conditions are fulfilled:
The cell is part of either the selected PLMN or the registered PLMN or PLMN of the Equivalent PLMN list and trackingAreaCode is provided for that PLMN either:
- The PLMN-ID of that PLMN is broadcast by the cell with no associated CAG-IDs and CAG-only indication in the UE for that PLMN (TS 23.501 [10]) is absent or false;
- Allowed CAG list in the UE for that PLMN (TS 23.501 [10]) includes a CAG-ID broadcast by the cell for that PLMN;
The cell selection criteria are fulfilled.
According to the latest information provided by NAS:
The cell is not barred, see clause 5.3.1;
The cell is part of at least one TA that is not part of the list of "Forbidden Tracking Areas" (TS 22.261 [12]), which belongs to a PLMN that fulfils the first bullet above.
Following exception to these definitions are applicable for UEs:
if a UE has an ongoing emergency call, all acceptable cells of that PLMN are treated as suitable for the duration of the emergency call.
9
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CELL SELECTION/RESELECTION PROCEDURE
Cell selection/reselection procedure
10
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Initial Cell Selection
Any Cell Selection
go here when no
USIM in the UE and no
subscription for an SNPN
USIM inserted or SNPN
subscription added
Camped on any cell
go here whenever a new PLMN or new
SNPN is selected
1 no cell information
stored for the PLMN or the SNPN
cell information stored for the PLMN
or the SNPN
Stored information
Cell Selection
no suitable cell found
no suitable cell found
Cell selection upon leaving connected
mode
suitable cell found 2
suitable
cell found Camped
normally
suitable cell found
no suitable cell found
leave idle/inactive
mode
return to idle/inactive
mode
Connected mode
Cell Reselection Evaluation
Process
suitable
cell found
trigger
no suitable
cell found
1 Cell Selection
when leaving connected
mode
no acceptable cell found
acceptable cell
found
acceptable cell found; move to
idle mode
suitable
cell found 2
leave idle mode
return to
idle mode
Connected mode
(Emergency calls only)
Cell
Reselection Evaluation Process
acceptable
cell found
trigger
no acceptable cell found
NAS indicates that registration on selected
PLMN or selected SNPN is rejected
(except with cause #12, #14 , #15 or #25
[9][14])
suitable cell found
RRC_IDLE and RRC_INACTIVE Cell Selection and Reselection
Cell selection
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Cell selection
12
a) Initial cell selection (no prior knowledge of which RF channels are NR frequencies):
• 1. The UE shall scan all RF channels in the NR bands according to its capabilities to find a suitable cell.
• 2. On each frequency, the UE need only search for the strongest cell.• 3. Once a suitable cell is found, this cell shall be selected.
b) Cell selection by leveraging stored information:• 1. This procedure requires stored information of frequencies and
optionally also information on cell parameters from previously received measurement control information elements or from previously detected cells.
• 2. Once the UE has found a suitable cell, the UE shall select it.• 3. If no suitable cell is found, the initial cell selection procedure in a)
shall be started.
NOTE:Priorities between different frequencies or RATs provided to the UE
by system information or dedicated signalling are not used in the
cell selection process.
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Cell selectionThe cell selection criterion S is fulfilled when:
Srxlev > 0 AND Squal > 0
where:
13
Srxlev = Qrxlevmeas – (Qrxlevmin + Qrxlevminoffset )– Pcompensation - QoffsettempSqual = Qqualmeas – (Qqualmin + Qqualminoffset) - Qoffsettemp
In RAN2 101bis meeting, it was agreed that:“The UE does not need to read system information from neighbor cells for determining cell quality and ranking. FFS how to capture in spec.”
Measured cell RX level value
Minimum required RX level in the cell ConnEstFail related
ConnEstFail related
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Cell reselectionThe high level criterions of current cell reselection scheme is:
absolute frequency priority(FP),
radio link quality, or
cell accessibility.
14
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
frequency priority could be configured by:1. Dedicated message (e.g. RRCRelease)2. Broadcast message (e.g. SIB2, SIB4 and SIB5)3. Inherit from another RAT
Limit needed measurements rules:1. Always measure higher FP frequency2. Conditionally measure equal or lower FP freq.
• E.g. Serving cell’s signal quality bellows a threshold
S criterion:• Measured cell should satisfy the S criterionR criterion:• Ranking of all cells that fulfil the cell selection criterion S
If 1. The cell is better ranked than the serving cell during a time
interval, and2. more than 1 second has elapsed since the UE camped on
the current serving cell
check if the access is restricted/barred
• Read MIB (in NR) (in LTE, read SystemInformationBlockType1)• If cell status is "not barred" and "not reserved“, treat this cell
as candidate
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Cell reselection
15
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
frequency priority could be configured by:1. Dedicated message (e.g. RRCRelease)2. Broadcast message (e.g. SIB2, SIB4 and SIB5)3. Inherit from another RAT
check if the access is restricted/barred
1. Dedicated message (e.g. RRCRelease) 2. Broadcast message (e.g. SIB2, SIB4 and SIB5)
3. Inherit from another RAT
The UE shall inherit the priorities provided by dedicated
signalling and the remaining validity time (i.e. T320 in NR and
E-UTRA), if configured, at inter-RAT cell (re)selection.
cellReselectionPriorities
freqPriorityListEUTRA
freqPriorityListNR
T320
FreqPriorityEUTRA
FreqPriorityEUTRA
FreqPriorityNR
FreqPriorityNR
carrierFreq
cellReselectionPriority
cellReselectionSubPriority
carrierFreq
cellReselectionPriority
cellReselectionSubPriority
maxFreq=8
maxFreq=8
SIB2 SIB2 contains cell re-selection information common for intra-frequency, inter-frequency and/or inter-RAT cell re-selection
SIB4 SIB4 contains information relevant only for inter-frequency cell re-selection
SIB5 SIB5 contains information relevant only for inter-RAT cell re-selection
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Cell reselection
16
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
Limit needed measurements rules:1. Always measure higher FP frequency2. Conditionally measure equal or lower FP freq.
• E.g. Serving cell’s signal quality bellows a threshold
check if the access is restricted/barred
If the serving cell fulfils Srxlev > SIntraSearchP and Squal > SIntraSearchQ, the UE may choose not to perform intra-frequency measurements.Otherwise, the UE shall perform intra-frequency measurements.
intra-frequency measurements
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Cell reselection
17
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
Limit needed measurements rules:1. Always measure higher FP frequency2. Conditionally measure equal or lower FP freq.
• E.g. Serving cell’s signal quality bellows a threshold
check if the access is restricted/barred
The UE shall apply the following rules for NR inter-frequencies and inter-RAT frequencies which are indicated in system information and for which the UE has priority.
inter-frequency measurements
For a NR inter-frequency or inter-RAT frequency with a reselection priority higher than the reselection priority of the current NR frequency, the UE shall perform measurements of higher priority NR inter-frequency or inter-RAT frequencies
For a NR inter-frequency with an equal or lower reselection priority than the reselection priority of the current NR frequency and for inter-RAT frequency with lower reselection priority than the reselection priority of the current NR frequency:- If the serving cell fulfils Srxlev > SnonIntraSearchP and Squal > SnonIntraSearchQ, the UE may choose not to perform measurements of NR inter-frequencies or inter-RAT frequency cells of equal or lower priority;- Otherwise, the UE shall perform measurements of NR inter-frequencies or inter-RAT frequency cells of equal or lower priority
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Cell reselection
18
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
S criterion:• Measured cell should satisfy the S criterionR criterion:• Ranking of cells that fulfil the cell selection
criterion S
check if the access is restricted/barred
The cell-ranking criterion Rs for serving cell and Rn for neighbouring cells is defined by:Rs = Qmeas,s +Qhyst - QoffsettempRn = Qmeas,n -Qoffset - Qoffsettemp
Qmeas RSRP measurement quantity used in cell reselections.
Qoffset For intra-frequency: Equals to Qoffsets,n, if Qoffsets,n is
valid, otherwise this equals to zero.
For inter-frequency: Equals to Qoffsets,n plus
Qoffsetfrequency, if Qoffsets,n is valid, otherwise this equals to
Qoffsetfrequency.
Qoffsettemp Offset temporarily applied to a cell as specified in TS
38.331 [3].
At RAN2 #101bis meeting: Number of actual good beams needs to be considered in cell quality derivation or cell
reselection rule for cell reselection. One solution should be brought to next meeting.
R2-1808330 Email discussion report of [101bis#66][NR] Good beams in cell reselection• Option2.2: Liner average of up to N best beams + Delta*(K-N)
supported by 12 companies (MTK, CMCC, OPPO, CATT, ASUSTeK, vivo, Apple, Huawei&HiSilicon, Sony, ZTE, Intel, DCM)
• Option2.3: For the cells with similar average value, UE reselects to the cell with more good beams
acceptable to 15 companies (Nokia, Samsung, Ericsson, Qualcomm, Interdigital, LG, DCM, CMCC, OPPO, CATT, vivo, Sony, ZTE, Huawei&HiSilicon, Apple)
Number of actual good beams issue
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Cell reselection
19
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
S criterion:• Measured cell should satisfy the S criterionR criterion:• Ranking of cells that fulfil the cell selection criterion S
check if the access is restricted/barred
Number of actual good beams issue in TS 38.304
If rangeToBestCell is not configured, the UE shall perform cell reselection to the highest ranked cell. If this cell is found to be not-suitable, the UE shall behave according to subclause 5.2.4.4.
If rangeToBestCell is configured, then the UE shall perform cell reselection to the cell with the highest number of beams above the threshold (i.e. absThreshSS-BlocksConsolidation) among the cells whose R value is within rangeToBestCell of the R value of the highest ranked cell.
If there are multiple such cells, the UE shall perform cell reselection to the highest ranked cell among them. If this cell is found to be not-suitable, the UE shall behave according to subclause5.2.4.4.
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Cell reselection
20
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
check if the access is restricted/barred
Cell status and cell reservations
Cell status and cell reservations are indicated in the MIB or SIB1 message as specified in TS 38.331 [3] by means of three fields:
- cellBarred (IE type: "barred" or "not barred") Indicated in MIB message. In case of multiple PLMNs indicated in SIB1, this field is common for all PLMNs
- cellReservedForOperatorUse (IE type: "reserved" or "not reserved") Indicated in SIB1 message. In case of multiple PLMNs indicated in SIB1, this field is specified per PLMN.
- cellReservedForOtherUse (IE type: "true") Indicated in SIB1 message. In case of multiple PLMNs indicated in SIB1, this field is common for all PLMNs.
If 1. The cell is better ranked than the serving cell during a time interval,
and2. more than 1 second has elapsed since the UE camped on the current
serving cell
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Cell reselection
21
Configure frequency priority
Perform Measurement
Find the highest ranked cell or the best cell
reselected to the cell
check if the access is restricted/barred
When cell status "barred" is indicated or to be treated as if the cell status is "barred“- The UE is not permitted to select/reselect this cell, not even for emergency calls.- The UE shall select another cell according to the following rule:
Reason for barred UE’s behavior Note
cell status is "barred" due to being unable to acquire the MIB
- exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds- select another cell on the same frequency if the selection criteria are fulfilled
The cell may be for EN-DC
the cell status is "barred" due to being unable to acquire the SIB1 ordue to trackingAreaCode being absent in SIB1
If the field intraFreqReselection in MIB message is set to "allowed"
- exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds
If the field intraFreqReselection in MIB message is set to "not allowed"
- exclude the barred cell as a candidate for cell selection/reselection for up to 300 seconds- UE shall not re-select a cell on the same frequency as the barred cell
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Initial Cell Selection
Any Cell Selection
go here when no
USIM in the UE and no
subscription for an SNPN
USIM inserted or SNPN
subscription added
Camped on any cell
go here whenever a new PLMN or new
SNPN is selected
1 no cell information
stored for the PLMN or the SNPN
cell information stored for the PLMN
or the SNPN
Stored information
Cell Selection
no suitable cell found
no suitable cell found
Cell selection upon leaving connected
mode
suitable cell found 2
suitable
cell found Camped
normally
suitable cell found
no suitable cell found
leave idle/inactive
mode
return to idle/inactive
mode
Connected mode
Cell Reselection Evaluation
Process
suitable
cell found
trigger
no suitable
cell found
1 Cell Selection
when leaving connected
mode
no acceptable cell found
acceptable cell
found
acceptable cell found; move to
idle mode
suitable
cell found 2
leave idle mode
return to
idle mode
Connected mode
(Emergency calls only)
Cell
Reselection Evaluation Process
acceptable
cell found
trigger
no acceptable cell found
NAS indicates that registration on selected
PLMN or selected SNPN is rejected
(except with cause #12, #14 , #15 or #25
[9][14])
suitable cell found
22
When camped normally, the UE shall perform the following tasks:
- monitor the paging channel of the cell as specified in clause 7 according to information
broadcast in SIB1;
- monitor Short Messages transmitted with P-RNTI over DCI as specified in clause
6.5 in TS 38.331 [3];
- monitor relevant System Information as specified in TS 38.331 [3];
- perform necessary measurements for the cell reselection evaluation procedure;
- execute the cell reselection evaluation process on the following occasions/triggers:
1) UE internal triggers, so as to meet performance as specified in TS 38.133 [8];
2) When information on the BCCH used for the cell reselection evaluation procedure
has been modified.
Short Messages can be transmitted on PDCCH using P-RNTI with or without
associated Paging message using Short Message field in DCI format 1_0 (see TS
38.212 [17], clause 7.3.1.2.1).
Bit Short Message
1 systemInfoModification
If set to 1: indication of a BCCH modification other than SIB6, SIB7 and SIB8.
2 etwsAndCmasIndication
If set to 1: indication of an ETWS primary notification and/or an ETWS
secondary notification and/or a CMAS notification.
3 – 8 Not used in this release of the specification, and shall be ignored by UE if
received.
Camped normally
DCI: Downlink Control Information
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Initial Cell Selection
Any Cell Selection
go here when no
USIM in the UE and no
subscription for an SNPN
USIM inserted or SNPN
subscription added
Camped on any cell
go here whenever a new PLMN or new
SNPN is selected
1 no cell information
stored for the PLMN or the SNPN
cell information stored for the PLMN
or the SNPN
Stored information
Cell Selection
no suitable cell found
no suitable cell found
Cell selection upon leaving connected
mode
suitable cell found 2
suitable
cell found Camped
normally
suitable cell found
no suitable cell found
leave idle/inactive
mode
return to idle/inactive
mode
Connected mode
Cell Reselection Evaluation
Process
suitable
cell found
trigger
no suitable
cell found
1 Cell Selection
when leaving connected
mode
no acceptable cell found
acceptable cell
found
acceptable cell found; move to
idle mode
suitable
cell found 2
leave idle mode
return to
idle mode
Connected mode
(Emergency calls only)
Cell
Reselection Evaluation Process
acceptable
cell found
trigger
no acceptable cell found
NAS indicates that registration on selected
PLMN or selected SNPN is rejected
(except with cause #12, #14 , #15 or #25
[9][14])
suitable cell found
23
This state is applicable for RRC_IDLE and RRC_INACTIVE state.
In this state, the UE shall perform cell selection process to find a suitable cell.
If the cell selection process fails to find a suitable cell after a complete scan of
all RATs and all frequency bands supported by the UE, the UE shall attempt to
find an acceptable cell of any PLMN to camp on, trying all RATs that are
supported by the UE and searching first for a high-quality cell, as defined in
subclause 5.1.1.2.
Acceptable cell:
An "acceptable cell" is a cell on which the UE may camp to obtain limited
service (originate emergency calls and receive ETWS and CMAS
notifications).
Any Cell Selection
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Initial Cell Selection
Any Cell Selection
go here when no
USIM in the UE and no
subscription for an SNPN
USIM inserted or SNPN
subscription added
Camped on any cell
go here whenever a new PLMN or new
SNPN is selected
1 no cell information
stored for the PLMN or the SNPN
cell information stored for the PLMN
or the SNPN
Stored information
Cell Selection
no suitable cell found
no suitable cell found
Cell selection upon leaving connected
mode
suitable cell found 2
suitable
cell found Camped
normally
suitable cell found
no suitable cell found
leave idle/inactive
mode
return to idle/inactive
mode
Connected mode
Cell Reselection Evaluation
Process
suitable
cell found
trigger
no suitable
cell found
1 Cell Selection
when leaving connected
mode
no acceptable cell found
acceptable cell
found
acceptable cell found; move to
idle mode
suitable
cell found 2
leave idle mode
return to
idle mode
Connected mode
(Emergency calls only)
Cell
Reselection Evaluation Process
acceptable
cell found
trigger
no acceptable cell found
NAS indicates that registration on selected
PLMN or selected SNPN is rejected
(except with cause #12, #14 , #15 or #25
[9][14])
suitable cell found
24
This state is only applicable for RRC_IDLE state. In this state, the UE shall
perform the following tasks:
- monitor the paging channel of the cell as specified in clause 7 according to
information broadcast in SIB1;
- monitor Short Messages transmitted with P-RNTI over DCI as specified in
clause 6.5 in TS 38.331 [3];
- monitor relevant System Information as specified in TS 38.331 [3];
- perform necessary measurements for the cell reselection evaluation procedure;
- execute the cell reselection evaluation process on the following
occasions/triggers:
1)UE internal triggers, so as to meet performance as specified in TS 38.133
[8];
2)When information on the BCCH used for the cell reselection evaluation
procedure has been modified.
- regularly attempt to find a suitable cell trying all frequencies of all RATs
that are supported by the UE. If a suitable cell is found, UE shall move to
camped normally state.
Acceptable cell:
An "acceptable cell" is a cell on which the UE may camp to obtain
limited service (originate emergency calls and receive ETWS and CMAS
notifications).
Camped on any cell
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PAGING
25
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Paging – PrinciplesRAN2 NR Ad Hoc-1
R2-1700016 Paging in NR
Paging in LTE
26
Agreements for NR paging:1: UE in RRC_IDLE and RRC_INACTVE state monitors paging/notification every DRX cycle. 2: UE monitors one paging occasion per DRX cycle. Paging occasion is the time interval over which a paging message is transmitted by gNB. 3: The length of DRX cycle is configurable. A default DRX cycle length is provided in system information. Additionally, a UE specific DRX cycle length can also be provided to UE in dedicated signalling.4: The number of paging occasions in the DRX cycle is configurable and provided in system information.5: If multiple paging occasions are configured by network in the DRX cycle then UEs can be distributed to these paging occasions based on UE ID.
T: DRX Cycle
PF: Paging Frames in DRX cycle PO: Paging Occasions in each PF
PF of UE with UE ID 1024 PO of UE with UE ID 1024
Ref: R2-1700016
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Paging - Beam sweeping RAN2 NR Ad Hoc-1
R2-1700016 Paging in NR
RAN1 has also discussed the paging transmission using multiple DL TX beams and has made the following agreements
27
Agreements for NR paging:6: RAN2 understanding is that paging can be transmitted at least using beam sweeping (content of paging may be a paging indicator or the paging message, FFS)7: Paging occasion can consists of multiple time slots (e.g. subframe or OFDM symbol). (Multiple time slots enables transmission of paging using a different set of DL TX beam(s) in each time slot, or could enable repetition - RAN1 decision).8: The number of time slots in a paging occasion is provided in system information.
RAN 1 Agreement:•For paging in multi-beam operation, support beam sweeping for paging, and study the following methods:
–Alt-1: Multiplexing paging with SS blocks•FFS: Details of paging
–Alt-2: Adding another round of beam sweeping for paging •Note: Another round of beam sweeping is different from the beam sweeping of SS burst set
–Other alternatives are not precluded
T: DRX Cycle
PF: Paging Frame (One Radio Frame)
PO: Paging Occasion (Multiple subframes)
E.g. 6 TX beams at gNB
TX1B1
TX2B2
TX3B3
TX4B4
TX5B5
TX6B6
sf0sf0 sf1sf1 sf2sf2 sf3sf3 sf4sf4 sf5sf5 sf6sf6 sf7sf7 sf8sf8 sf9sf9
PO
Ref: R2-1700016
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Paging - Beam sweeping RAN2 NR Ad Hoc 1801 (Jan 2018)
R2-1800152 Issues about NR paging occasion CATT
R2-1800078 Paging in NR – Beamforming Aspects Samsung
Paging transmission using TX beam sweeping and TX beam repetition in PO
28
Agreements1 From RAN2 understanding for paging in multi-beam operation TX beam sweeping can be performed in paging occasion. Paging transmission from each TX beam is not repeated for RX beam sweeping at UE.
T: DRX Cycle
POPO
TX1B1
TX2B2
TX3B3
TX4B4
TX5B5
TX6B6
s0s0 s1s1 s2s2 s3s3 s4s4 s5s5
TX beam(s) is repeated to enable RX beam sweeping.
TX beam(s) is repeated to enable RX beam sweeping.
s6s6 s7s7 s8s8 s9s9 s10s10 s11s11
TX1B1
TX2B2
TX3B3
TX4B4
TX5B5
TX6B6
UE RX B1
UE RX B2
Paging Time slotPaging Time slot
Ref: R2-1800078
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Paging - Beam sweepingRAN2#101 (Feb 2018)
R2-1803644 Definition of Paging OccasionHuawei
Proposal 2: The UE can assume that the same paging message is repeated in all beams of the sweeping pattern, and the UE may monitor any beam that is good enough for successful reception.
29
Agreements1: The length of one PO in case of beam sweeping is one period of beam sweeping 2: The UE can assume that the same paging message is repeated in all beams of the sweeping pattern.
Ref: R2-1800078
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Paging - DRXRAN2 NR Ad Hoc 1801 (Jan 2018)
R2-1801179 Discussion on maximum idle mode DRX value in NR Huawei
The main motivation to extend idle mode DRX cycle beyond 2.56s is for MTC and NB-IoT devices.
Since mMTC is not in the scope of Rel-15 NR, we think RAN2 don’t need to extend the idle mode DRX cycle in Rel-15.
30
Agreements1 Idle mode/inactive mode DRX cycle configuration in NR should take the default DRX cycle parameter in LTE as baseline.2 The maximum idle/inactive mode DRX value in NR should be 2.56s.
RAN2 #105 (Feb 2019)
=> RAN2 will consider extending the DRX cycle length to
10.24 in idle and inactive mode.
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Paging - Paging ReceptionR2-1812276 Correction to the UE identity for PO calculation Ericsson
The paging occasion is determined based on the UE identity which in turn is derived from IMSI.
UE_ID = IMSI mod 1024
The number 1024 in the above formula is due to the maximum DRX cycle which is 1024 radio frames long
IMSI privacy is one of the main security requirements in 5GS and SA3 has made additional efforts to ensure that IMSI is not exposed on the air interface.
Proposal 1: 5G-S-TMSI is used as UE identity for calculating the paging occasion
Note:
This contribution is a re-submission of R2-1809621 which was discussed at RAN2#1807.
The discussion resulted in the LS [6] being sent to SA3 and asks SA3 to answer if they see any privacy concerns with using IMSI as UE identity.
31
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Paging - Paging Reception
R2-1813267 Reply LS on UE identity for PO calculation (S3-182539; contact: Ericsson) SA3
SA3 would like to point out that IMSI privacy is one of the main privacy features in 5G and SA3 has made additional efforts to make it possible that IMSI can be concealed over-the-air (see TS 33.501).
Further to support IMSI privacy, SA2 has decided that IMSI based paging is not supported in 5G
Therefore, SA3 requests RAN2 to calculate paging occasion in NR without using IMSI, and to use other temporary identifiers like 5G-S-TMSI.
R2-1812276 Correction to the UE identity for PO calculation Ericsson CR Rel-15 38.30415.0.0 0005 2 F NR_newRAT-Core R2-1812276
=> Agreed to be merged into the rapporteur's CR
32
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Paging - Paging Reception
LTE Paging Reception NR Paging Reception
33
Find out paging frame (PF)
Find out paging occasions (PO)
Monitor Paging message (PM)
SFN for the PF is determined by: (SFN mod T) = (T div N)*(UE_ID mod N)
SFN for the PF is determined by: (SFN + PF_offset) mod T = (T div N)*(UE_ID mod N)
by mapping table:
Find out paging frame (PF)
Find out paging occasions (PO)
Find out time slot
Monitor Paging message (PM)
PDCCH monitoring occasions
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Paging - Paging Reception
The PDCCH monitoring occasions for paging are determined according to pagingSearchSpace as specified in TS 38.213 [4] and firstPDCCH-MonitoringOccasionOfPO and nrofPDCCH-MonitoringOccasionPerSSB-InPOif configured as specified in TS 38.331 [3].
When SearchSpaceId = 0 is configured for pagingSearchSpace, the PDCCH monitoring occasions for paging are same as for RMSI as defined in clause 13 in TS 38.213 [4].
When SearchSpaceId = 0 is configured for pagingSearchSpace, Ns is either 1 or 2.
For Ns = 1, there is only one PO which starts from the first PDCCH monitoring occasion for paging in the PF.
For Ns = 2, PO is either in the first half frame (i_s = 0) or the second half frame (i_s = 1) of the PF.
SearchSpaceId = 0, 一個radio frame至多一個 PO,
34
Ns: number of paging occasions for a PF
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Paging – Paging Reception
A PO is a set of 'S*X ' consecutive PDCCH monitoring occasions where 'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1 and X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwise.
35
A PO is a set of 'S' consecutive PDCCH monitoring occasions
For example, S = 2 actual transmitted SSBs
The PO is a set of 2 consecutive PDCCH monitoring occasions
PF
第1個 PMO
(PDCCH
monitoring
occasions)
第2個 PMO
PO
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Paging – Paging Reception
The [x*S+K]th PDCCH monitoring occasion for paging in the PO corresponds to the Kth transmitted SSB, where x=0,1,…,X-1, K=1,2,…,S.
X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwisex=0
'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1For example, S = 4 -> 有4個SSBs
K = 1, 2, 3, 4
第1個 PDCCH monitoring occasion 對應第1個transmitted SSB
第2個 PDCCH monitoring occasion 對應第2個transmitted SSB
第3個 PDCCH monitoring occasion 對應第3個transmitted SSB
第4個 PDCCH monitoring occasion 對應第4個transmitted SSB
The PDCCH monitoring occasions for paging which do not overlap with UL symbols (determined according to tdd-UL-DL-ConfigurationCommon) are sequentially numbered from zero starting from the first PDCCH monitoring occasion for paging in the PF.第1個 PDCCH monitoring occasion (i.e. PDCCH monitoring occasion NO. 0)對應第1個transmitted SSB
第2個 PDCCH monitoring occasion (i.e. PDCCH monitoring occasion NO. 1)對應第2個transmitted SSB
第3個 PDCCH monitoring occasion (i.e. PDCCH monitoring occasion NO. 2)對應第3個transmitted SSB
第4個 PDCCH monitoring occasion (i.e. PDCCH monitoring occasion NO. 3)對應第4個transmitted SSB
36
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Paging – Paging Reception
When firstPDCCH-MonitoringOccasionOfPO is present, the starting PDCCH monitoring occasion number of (i_s + 1)th PO is the (i_s + 1)th value of the firstPDCCH-MonitoringOccasionOfPO parameter; otherwise, it is equal to i_s * S*X.
X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwise
x=0
'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1
For example, S = 4 -> 有4個SSBs
K = 1, 2, 3, 4
firstPDCCH-MonitoringOccasionOfPO is not present
Starting PDCCH monitoring occasion number = i_s * S*X
For example,
i_s = 0 的UE => Starting PDCCH monitoring occasion number = 0
i_s = 1 的UE => Starting PDCCH monitoring occasion number = 4
37
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Paging – Paging Receptionpaging-SearchSpace configuration (Periodicity: 5 slots; Offset: 0; duration: 2 slots; monitoringSymbolsWithinSlot: 00100000100000;CORESET-time-duration: 4 OFDM symbols)
38
R2-1809477
SFN = F1
PDCCH
Monitoring
Occasion 0
PDCCH
Monitoring
Occasion 1
Slots corresponding to 1st PO
Slots corresponding to 2nd PO
PDCCH
Monitoring
Occasion 2
PDCCH
Monitoring
Occasion 3
PDCCH
Monitoring
Occasion 4
PDCCH
Monitoring
Occasion 5
PDCCH
Monitoring
Occasion 6
PDCCH
Monitoring
Occasion 7
SSB 1
SSB 1
SSB 2
SSB 2
SSB 3 SSB 4
SSB 3 SSB 4
nB = 2T; Reference Frame determined by UE: SFN ‘F1’; Number of SSBs = 4
i_s = 0 PO = 1st PO = PDCCH monitoring occasion 0,1,2,3
i_s = 1 PO = 2nd PO = PDCCH monitoring occasion 4,5,6,7 (?? Why not 0, 1, 2, 3)
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Paging – Paging Reception
A PO is a set of 'S*X ' consecutive PDCCH monitoring occasions where 'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1 and X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwise.
39
A PO is a set of 'S' consecutive PDCCH monitoring occasions
S = 2 actual transmitted SSBs
The Kth PDCCH monitoring occasion for paging in the PO
corresponds to the Kth transmitted SSB
PF
第1個 PMO
(PDCCH
monitoring
occasions)
第2個 PMO
SSB 1 SSB 2
PO
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Paging – Paging Reception
A PO is a set of 'S*X ' consecutive PDCCH monitoring occasions where 'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1 and X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwise.
The [x*S+K]th PDCCH monitoring occasion for paging in the PO corresponds to the Kth transmitted SSB, where x=0,1,…,X-1, K=1,2,…,S.
X is the nrofPDCCH-MonitoringOccasionPerSSB-InPO if configured or is equal to 1 otherwise
x=0, 1 ->第1個transmitted SSB對應第一個([0*2+1]th )與第三個([1*2+1]th )PDCCH monitoring occasion
40
A PO is a set of 'S' consecutive PDCCH monitoring occasions
S = 2 actual transmitted SSBs
The Kth PDCCH monitoring occasion for paging in the PO
corresponds to the Kth transmitted SSB
nrofPDCCH-MonitoringOccasionPerSSB-InPO = 2
PF
第1個 PMO 第2個 PMO
SSB 1 SSB 2
PO
第3個 PMO 第4個 PMO
SSB 1 SSB 2
If X > 1, when the UE detects a PDCCH transmission
addressed to P-RNTI within its PO, the UE is not required to
monitor the subsequent PDCCH monitoring occasions for
this PO.
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Paging – Paging Reception
When firstPDCCH-MonitoringOccasionOfPO is present, the starting PDCCH monitoring occasion number of (i_s + 1)th PO is the (i_s + 1)th value of the firstPDCCH-MonitoringOccasionOfPO parameter; otherwise, it is equal to i_s * S*X.
firstPDCCH-MonitoringOccasionOfPO is not present
Starting PDCCH monitoring occasion number = i_s * S*X
firstPDCCH-MonitoringOccasionOfPO is present
Starting PDCCH monitoring occasion number = (i_s + 1)th PO is the (i_s + 1)th value of the firstPDCCH-MonitoringOccasionOfPO
41
10 slots = 140 symbols
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Paging – Paging Reception
firstPDCCH-MonitoringOccasionOfPO is not present
Starting PDCCH monitoring occasion number = i_s * S*X
For a UE with i_S = 0, its PO is starting from PDCCH monitoring occasion number = 0
42
A PO is a set of 'S' consecutive PDCCH monitoring occasions
S = 2 actual transmitted SSBs
The Kth PDCCH monitoring occasion for paging in the PO
corresponds to the Kth transmitted SSB
PF
第0個 PMO 第1個 PMO
1st PO
第2個 PMO 第3個 PMO
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Paging – Paging Reception
firstPDCCH-MonitoringOccasionOfPO is present
Starting PDCCH monitoring occasion number = (i_s + 1)th PO is the (i_s + 1)th value of the firstPDCCH-MonitoringOccasionOfPO
For a UE with i_S = 0, its PO is starting from PDCCH monitoring occasion number = 1st value of the firstPDCCH-MonitoringOccasionOfPO
43
A PO is a set of 'S' consecutive PDCCH monitoring occasions
S = 2 actual transmitted SSBs
The Kth PDCCH monitoring occasion for paging in the PO
corresponds to the Kth transmitted SSB
1st value of the firstPDCCH-MonitoringOccasionOfPO
= 1
PF
第0個 PMO 第1個 PMO
1st PO
第2個 PMO 第3個 PMO
Thank you for listening
44