5G New Radio in Bullets_Chris Johnson

5G NR in BULLETS 11 MEASUREMENT REPOB�TING * A Base Station can use dedicated signalling to configure a UE in RRC Connected mode to perform and report measurements. Measurements can be intra-frequency, inter-frequency or intcr-sys:tcm * Intra and inter-frequency measurements can be based upon either SSIPBCH Blocks or CSI Reference Signal Resources. In both cases, measurements can be 'beam level' or 'cell level'. A beam level measurement is recorded from an SSIPBCH Block with a specific Block Index, or from a CS[ Reference Signal Resource with a specific Resource Identity. Cell level measurements are derived from beam level measurements using the rules described in section 11. n * The definition of intra-frequency measurements depends upon the measurement resource: -.o SSIPBCH Block intra-frequency measurements correspond to scenarios where both the serving cell and neighbouring cell use the same SS/PBCH Block center frequency and subcarrier spacing o CSI Reference Signal intra-frequency measurements correspond to scenarios where the neighbouring cell is configured with a CSI Reference Signal Resource bandwidth which is confined within the bandwidth of the CSI Reference Signal Resource belonging to the serving cell, and both csr Reference Signals use the sam,� subcarrier spacing * Within the release 15 version of the 3GPP speciftcations, inter-system measurements are restricted to LTE (4G). It is not possible to configure inter-system measurements for GSM (2G), LJMTS (3G) nor CDMi\\2000 (3G) * A measurement configuration includes: Measurement Identities, Measurement Objects, Reporting Configurations, Quantity Configurations and Measurement Gap Configurations Measurement Identity o a Measurement Identity links a Reporting Configuration to a Measurement Object, i.e. each Measurement Identity includes a pointer towards a Reporting Configuration and a pointer towards a Measurement Object. Multiple Measurement Identities can be used to link multiple Reporting Configurations to the same Measurement Object. Alternatively, multiple Measurement Identities can be used to link a single Reporting Configuration to multiple Measurement Objects o the Measurement Identity is useu as a reference when the UE provides measurement results within an RRC: Measurement Report message, i.e. a UE provides a set of measurement results and states that they arc applicable to a specific Measurement Identity. An RRC: Measurement Reporl docs not explicitly indicate the Measurement Object nor the Reporting Configuration Measurement Object o in the case of intra and inter-frequency measurements, a Mcaisurement Object identifies lhc time and frequency location of the SSIPBCH Blocks and csr Reference Signal Resources to be measured. It also specifies the corresponding subcarricr spacings. A single Measurement Object can specify both SSIPBCH Bloclk and CSI Reference Signal information. The Reporting Configuration is responsible for selecting between these two types of measurement resource. The Measurement Object can specify a set of cell specific measurement offsets to make individual cells appear either more or less attractive. Cells can be 'Blacklisted' to exclude them from event evaluation and measurement rep,orting. In addition, a set of 'Whitelisted' cells can be specified. The inclusion of 'Whitelisted' cells within the Measurement Object does not necessarily mean that they will be used. The Reporting Configuration is responsible for indicating when the 'Whitelisted· cells should be used. When used, the 'Whitclistcd' cells are the only cells taken into account for event evaluation and measuJfcment reporting. The Measurement Object also includes parameters which are used when deriving cell level measurements from beam level measurements o in the case of inter-system measurements, a Measurement Object identities a speci fie LTE carrier and a corresponding measurement bandwidth. The Measurement Object can also specify cell specific measurement offsets to make individual cells appear either more or less attractive. Cells can be 'Blacklisted' to exclude them from event evaluation and measurement reporting Reporting Configurations o a Reporting Configuration can specify Periodic, Event Triggered or Cell Global Identity(CG)) reporting • a Periodic configuration for NR reporting specifics the Reference Signal type (SS/PBCH or CSJ Reference Signal), a reporting interval and a report amount. For example, a UE can be itnstructed to provide 4 reports based upon the SSIPBCH with an interval of I 0.24 seconds between each report. Alternatively, a UE could be instructed to provide 32 reports based upon the CSI Reference Signal with an interval of 640 ms bctwce111 each report. The report amount can be set to 'infinity' when a continuous stream of reports is required. The configuration also specifies the 'cell level' measurement quantities to be included within each report and the maximum number ofcells to be reported. Similarly. the configuration specifics the 'beam level' measurement quantities and the maximum number of beams to be reported. The 'cell level' and 'beam level' measurement quantities can be specified as any combination of RSRP, RSRQ and SINR. There are also flags to indicate whether or not beam level measurements should be reported, and whether or not the set of 'Whitelistcd' cells specified within the Measurement Object should be applied • a Periodic configuration for LTE reporting specifics a reporting interval and a report amount. It also specifies the reporting quantity and the maximum number of cells to report. Similar to the periodic Reporting Configuration for NR, the reporting quantity can be specified as any combination of RSRP, RSRQ and SINR • an Event Triggered configuration for NR reporting proviidcs the parameters for a specific Measurement Reporting Event (Event A I, i\\2, A3, A4, A5, or A6). These Measuremen1l Reponing Events are described later in this section. The Reporting 396

sG NR in BULLETS Configuration also specifics the Reference Signal type (SSIPBCH or CSI Reference Signal) used to trigger the event, the number ofreports which are sent after the event has triggered and the rime interval between those reports. The configuration also specifies the 'cell level' measurement quantities to be included within each report and the maximum number ofcells to be reported. Similarly, the configuration specifies the 'beam level' measurement quantities and the maximum number of beams to be reported. The 'cell level' and 'beam level' measurement quantities can be specified as any combination ofRSRP, RSRQ and STNR. There arc also flags to indicate whether or not beam level measurements should be reported, and whether or not the set of'Whitelisted' cells specified within the Measurement Object should be applied • an Event Triggered configuration for LTE reporting provides the parameters for a specific Measurement Reporting Event (Event B I or B2). The Reporting Configuration also specifies the Reference Signal type (SS/PBCH or CSI Reference Signal) used to trigger the event (applicable when using Event B2 which depends upon both NR and LTE measurements) and used for any reported NR measurements. In addition, the Reporting Configuration specifies the number ofreports which are sent after tNhRe ,etvhe,enrtehpaosrttrinigggqeureadntaintydctahne time interval between those reports. Similar to the event triggered Reporting Configuration for be specified as any combination ofRSRP, RSRQ and SINR • a CGI Reporting Configuration for either NR or LTE specifies the set ofPhysical layer Cell Identities (PCI) for which the UE is required to decode and report the Cell Global Identity (CGI). This Reporting Configuration can be used for neighbour addition and neighbour validation within the context ofUE based Automatic Neighbour Relations (ANR) * Figure 327 illustrates an example ofMeasurement Identities being used to link a set ofReporting Configurations to a set of Measurement Objects. This example illustrates that multiple Rcpo1rting Configurations can be linked to the same Measurement Object, and that a single Reporting Configuration can be linked to multiple Measurement Objects Measurement .., \" I }Measurement NR Object 1 Identity 1 -[ lReporting Reporting Intra-Frequency Config.2 Config. 1 carrier Measurement ldentity2 NR Inter-Frequency '- Measurement carrier ldentity3 iMeasurement LT£ ,, Inter-System C JObject2 carrier Measurement [ }Measurement Jdentity4 { JReporting Object3 Conjig.3 Figure 327 - Measurement Identities linking Mea1surement Objects to Reporting Configurations * Figure 328 illustrates a Measurement Identity used to link a periodic NR Reporting Configuration to an NR Measurement Object. This example illustrates that the 'Reference Signal Type' within the Rejporting Configuration is used to select between the SS/PBCH Block and CSI Reference Signal info11T1ation within the Measurement Object Meas-urement ldentity l I - !-----+- Measurement Object Identity 'x' lReport Configuration Identity 'y'-+--� Quantity Configuration 'a' Measurement Object 'x' Reporting Configuration 'y' Periodic C 7Cell Level-SS/PBCH - ll;cBaCrrHieproSspiaticoinng& RSRP Filter Coefficient - jlI-[ SS/PBCH Selection Reference Signal Type RSRQ Filter Coefficient or SINR Filter Coefficient Report Interval CS/ RS Report Quantity Cell Level-CS/ RS CS/ RS position & Report Quantities Subcorrier Spacing I -1RSRP Filter Coefficient I IMox. number of cells RSRQ Filter Coefficient I Report Quantities Cell Level SINR Filter Coefficient : Quantity Config Index I I IMax.number of beams Beom Leve1 Beam Level-SS/PBCH RSRP Filter Coefficient I Measurement Offsets RSRQ Filter Coefficient I Blacklisted Cells I SJNR Filter Coefficient I Whitelisted Cells I Include 'Beam Measurements' Flog Beam Level-CS/ RS Apply 'Whitelisted Cells' Flog RSRP Filter Coefficient RSRQ Filter Coefficient I Beam level to Cell level I 5/NR Filter Coefficient derivation parameters Figure 328- Measurement Identity linking a Measurement Object for NR to a Periodic Reporting Configuration 39'7

5G NR in BULLETS * The example in Figure 328 also illustrates that the Measurement Object includes a pointer towards a Quantity Configuration. The Quantity Configuration specifics the set ofFilter Coefficients which are to be used for Layer 3 filtering ofthe measurements. It is possible to configure up to 2 Quantity Configurations for NR so the pointer has a value of I or 2. It is only possible to configure I Quantity Configuration for LTE so Measurement Objects for LTE do not require this pointer * Figure 329 illustrates a Measurement Identity being used to link an event triggered NR Reporting Configuration to an NR Measurement Object. This example illustrates that the event triggered Reporting Configuration includes the parameter set for a specific Measurement Reporting Event. In this case, the flag used to activate the Whitclisted cells is included within the parameter set for each Measurement Reporting Event. Events Al and A2 are exceptions which do not require this flag because they only depend upon the serving cell and do not require neighbour cell measurements Measurement Identity �---_,_ Measurement Object Identity 'x' l IReport Configuration Identity 'z' _,___ i Quan,t·ty can,1figurar,on ,a, -Measurementob�·ect'X' Reporting Configuration 'z' ljI Event Triggered Cell Level- SS/PBCH SS/PBCH position & SS/PBCH Selection Reference Signal Type I ]RSRP Filter Coefficient Subcarrier Spacing or Report Interval RSRQ Filter Coefficient Report Quantity SINR Filter Coefficient lI[ CS/RS CS/ RS position & Cell Level- CS/RS Subcarrier Spacing I 11 11 IEventAl I I·RSRP Filter Coefficient :Quantity Config Index EventA2 EventA3 RSRQ Filter Coefficient SINR Filter Coefficient I IMeasurement Offsets I 11 11 IReport QuantitiesEventA4EventASEventA6 I 7 IBlacklisted Cells Beam Level- SS/PBCH I IMax. number of cells Report Quantities Ce// Level [RSRP Filter Coefficient RSRQ Filter Coefficient I •IIWhitelisted Cells IMax. number of beams Beam Level SINR Filter Coefficient ·- I Beam level ta Cell level ] Include Beam Measurements Flag Beam Level- CS/ RS derivation parameters RSRP Filter Coefficient I IRSRQ Filter Coefficient SINR Filter Coefficient Figure 329 - Measurement Identity linking a Measurement Object for NR to an Event Triggered Reporting Configuration Quantity Configurations o the Quantity Configuration specifies the Layer 3 filtering coefficients which define the memory ofthe Layer 3 filtering. A large filter coefficient corresponds to a filter with a longer memory. This means that a specific measurement result impacts the output of the filter for a longer period oftime (the averaging window increases). Layer 3 filtering is applied before evaluating Measurement Reporting Events (A I, A2, A3, etc) and before reporting measurements to the Base Station (in contrast, CS! reporting allows RSRP measurements to be sent at Layer I without Layer 3 filtering). Layer 3 filtering is described in section 11.2 o in the case ofNR, it is possible to configure up to 2 Quantity Configurations. Each Quantity Configuration can specify up to 4 sets offilter coefficients to cater for Cell Level and Beam Level measurements from both SS/PBCH Blocks and CS! Reference Signal Resources. Separate filter coefficients are specified for each measurement quantity (RSRP, RSRQ and SINR). o In the case ofLTE, it is possible to configure a single Quantity Configuration which includes a single set offilter coefficients. Figure 330 illustrates the 4 sets offilter coefficients for NR and the single set for LTE 1 or 2 Quantity Configuratfons INR Beam Level Quantity 1 Quantity Configuration for NR Configuration 1 for LTE Cell Level ml SS/PBCH Block i i i Cell specific Reference Signal RSRP Filter Coefficient RSRP Filter Coefficient CS/ Reference Signal SS/PBCH Black CS/Reference Signal RSRQ Filter Coefficient RSRQ Filter Coefficient RSRP Filter Coefficient RSRP Filter Coefficient RSRP Filter Coefficient SINR Filter Coefficient SINR Filter Coefficient RSRQ Filter Coefficient RSRQ Filter Coefficient RSRQ Filter Coefficient SINR Filter Coefficient SINR Filter Coefficient SINR Filter Coefficient Figure 330- Configuration of Layer 3 Filter Coefficients within Quaotity Configurations 398

5G NR in BULLETS Measurement Gap Configurations 0 Measurement Gaps arc required ifa UE is requested to perform measurements which cannot be completed while the UE is tuned to the current serving cell. Measurement Gaps impact performance because they interrupt both uplink and downlink data transfer. This means that Measurement Gaps should only be configured when necessary. Event A2 can be used as a triggering mechanism to configure Measurement Gaps. Event A2 indicates that the curTcnt serving cell has become weak so it may be necessary to complete an inter-frequency or inter-system handover o In the case ofLTE, Measurement Gaps arc typically configured for inter-frequency and inter-system measurements. The measurement gaps provide sufficient time for the UE to re-tune its transceiver to the target carrier, complete the set of measurements and then re-tune its transceiver back to the original carrier. It is common to assume that each re-tuning operation requires up to 0.5 ms o In the case ofNR, Measurement Gaps may be required for intra--frequency measurements, in addition to inter-frequency and inter­ system measurements. For example: • within Frequency Range 2 it is expected that all UE will use analogue receiver bcamforming. The UE beam will normally be directed towards the serving cell, whereas neighbour cell measurements will require the beam to be directed towards the neighbouring cells. Measurement Gaps will be required while the UE redirects its beam and temporarily stops transmitting/receiving with the serving cell • a UE may be configured with an active Bandwidth Part which does not contain the intra-frequency SS/PBCH Block. In this case, the UE has to re-tune its transceiver to receive the intra-frequency SS/PBCH Block. This scenario is similar to re-tuning for inter-frequency measurements o Measurement Gaps arc configured using the parameter structure shown in Table 246. It is possible to configure different Measurement Gap patterns for Frequency Ranges I and 2 (gapFRI and gapFR2). Alternatively, a single Measurement Gap pattern can be configured for both Frequency Ranges (gapUE) gapFR2 MeasGapConfig gapOITset GapConfig mgl 0 lo 159 gapFRI SetupRelease { GapConfig } mgrp 1.5, 3, 3.5, 4, 5.5, 6 ms mgla 20, 40, 80, 160 ms I gapUE SetupRelcasc f GapConfig } 0, 0.25, 0.5 ms I SetupRelease { GapConfig } Table 246 - Measurement Gap Configuration o Measurement Gaps start during radio frames and subframes which satisfy the following criteria: SFN mod (MGRP I 10) = FLOOR (gapO.ffset I I 0) Subframe = gapO.ffset mod I 0 where, MGRP is the Measurement Gap Repetition Period, and gapO.ffset can be configured with a value between O and MGRP - I o For example, when the MGRP is configured with a value of40 ms and gapO.ffset is configured with a value of35 then Measurement Gaps start during subframe 5 ofSFN 3, 7, l I, 15, 19, etc o The duration ofeach Measurement Gap is configured using the Measurement Gap Length (MGL) which can have a value between 1.5 and 6 ms o 3GPP TS 38.133 specifics the set of24 Gap Patterns presented in Table 247 by defining 24 combinations ofMGL and MGRP. These Gap Patterns are designed to accommodate the timing ofthe NR and LTE transmissions to be measured. For example, when using Frequency Range I with a 15 kHz subcarrier spacing, a se:t of8 SS/PBCH Blocks corresponding to 8 beams can be transmitted within a 5 ms time window. Adding an additional I ms for transceiver re-tuning leads to the 6 ms MGL. Smaller MGL can be used iffewer SS/PBCH Blocks are transmitted or ifa hig:her subcarrier spacing is configured Gap Pattern MGt L(ms) MGRP(ms) Ga~p Pallem MGL(ms) MGRP(ms) Gap Pallcm MGL(ms) MGRP (ms) 0 6 40 8 4 80 16 3.5 20 I 6 80 9 4 160 17 3.5 40 2 3 40 10 3 20 18 3.5 80 3 3 80 II 3 160 19 3.5 160 4 6 20 12 5.5 20 20 1.5 20 6 - 13 5.5 40 21 1.5 40 .5 4 160 14 5.5 80 22 1.5 80 4 20 15 5.5 160 23 1.5 160 6 40 7 Table 247 - Gap Pattern Configurations 399

5G NR in BULLETS o The Measurement Gap Configuration also specifies a Measurement Gap Timing Advance (MGTA). The MGTA can be used to advance the timing ofthe Measurement Gap to improve the alignment between the Measurement Gaps and the SSIPBCH Block Measurement Time Configuration (SMTC). The MGTA allows adjustment by 0.25 or 0.5 ms whereas the gapO.fJ.set allows adjustment by I ms. Figure 450 within section 15.2 illustrates an example requirement for an MGTA * 3GPP References: TS 38.331, TS 38.133 11.1 CELL LEVEL RESULTS * Layer I measurements arc recorded from specific beams which arc associated with an SSIPBCII Block or a CST Reference Signal. Cell reselection and handover procedures operate at a cell level rather than at a beam level, i.e. they involve changing the serving cell. This means it is more appropriate to use a cell level measurement rather than a beam level measurement * 3GPP has specified the rules for generating a cell level measurement from one or more beam level measurements within TS 38.331 * In the case ofSSIPBCH Block measurements, the derivation is based upon the following parameters: o nrojSS-8/ocksToAverage (value ranges from 2 to 16) o absThreshSS-BlocksConsolidation (value ranges from 0 to 127) * These parameters can be broadcast within SIB2 and SIB4 for the purposes ofcell reselection. Dedicated signalling can be used to configure them within specific Measurement Objects for the purposes ofmeasurement reporting and handovcrs. The value of absThre.shSS-8/ocksConsolidation is mapped onto an RSRP or RSRQ value for cell reselection. Similarly, it is mapped onto an RSRP, RSRQ or SJNR value for handovers. The look-up tables for these mappings arc presented in section 0 * Ifa UE is not configured with both parameters then the UE uses the measurement from the strongest beam as the cell level measurement. Similarly, ifnone ofthe beam level measurements exceed the threshold defined by absThreshSS-BlocksConsolidation * then the measurement from the strongest beam is used as the cell level measurement Otherwise, the cell level measurement is defined as the linear average ofthe strongest measurement results which exceed the threshold defined by absThreshSS-BlocksConsolidation, including a maximum ofnrojSS-8/ocksToAverage beams within the average. Examples ofthis derivation are illustrated in Figure 331 Cel level result calculated as average CeD level rasu/1 calculated as average Cel level result sel equal to the across 3 beams across 2 beams strongest beam level result abs ThreshSS­ BlocksConsolidalion nrofSS-BlocksToAverage = 3 nrofSS-BlocksToAverage = 3 nrofSS-BlocksToAverage = 3 Figure 331 - Derivation of cell level results from beam level results * In the case ofCSI Reference Signal measurements, the principles ofthe derivation arc the same but the following parameters arc used: o nrojCSJ-RS-ResourcesToAverage (value ranges from 2 to 16) o absThreshCSI-RS-Consolidation (value ranges from Oto 127) * These parameters arc not broadcast within the SIB because they are not applicable to cell reselection. Dedicated signalling can be used to configure them within specific Measurement Objects for the purposes ofmeasurement reporting and handovcrs * Figure 3 32 illustrates the derivation ofcell level results followed by Layer 3 filtering and the subsequent evaluation ofMeasurement Reporting Events. Measurement Reporting Events may require cell level measurements from both the serving cell and neighbouring * cells. In this case, the processing illustrated in Figure 332 is completed for each cell Figure 332 also illustrates the Layer 3 filtering ofbeam level measurements which arc then ordered to allow selection for reporting 400

5G NR in BULLETS Beam 1 ---I► Layer 1 Filtering :□------.1 f- -Derivation ofLayer 3 FilteringEvaluation Event Trigger & Beam 2 ---I► Layer 1 Filtering Cell Level of Reporting Laye•r 3 Cell Level ResultsOther Layer 3 Criteria Mea.suremen/s Beam N ---I► ... ... Filtered Cell Level Results Layer 1 Filtering UE Implementation - □.~ Layer 3 Filtering i------- Specific Filtering - Layer 3 Filtering i----. Beam � Layer 3 Beam Level ... ...Selection � Measurements � -- Layer 3 Filtering i----. Figure 332 - Processing of beam level measurements 11.2 LAYER 3 FILTERING * Layer 3 filtering is applied using the equation below: Fn = (l - a) X Fn-i + a X Measn where, Fn is the updated filtered measurement result and Fn-1 is the previous filtered measurement result a= 0 _5(k 141 where k is the appropriate tilter coefficient Mcasn is the latest measurement result (either cell level or beam level) * The filter coefficient can be configured with values of {0, I, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19}. Filtering is not applied ifthe filter coefficient is set equal to 0, i.e. a= I. A default value of4 is assumed if the filter coefficient is not configured * Figure 333 illustrates the impulse response for each ofthe filter coefficient values assuming a new result is calculated every 200 ms. The impulse response is generated by feeding a single value of' I' into the filter. This illustrates that the filter has gn:ater memory when using lar;ger filter coefficients 0.9 FC=19 - - - ·FC=0 --FC=1 - - - -FC=2 0.8 FC=3 - - - -FC=4 --FC=5 FC=8 0.7 - - - -FC=6 --FC=7 --FC=13 .:e:,- 0.6 --FC=9 - - - •FC=11 - - . ·FC=19 ::, •FC=15 --FC=17 0 0.5 Q) ff 0.4 0.3 0.2 0.1 0 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (seconds) Figure 333 - Impulse response of Layer 3 filter * Figure 333 assumes that Layer I measurements arc fed into the filter at a rat,e,. ofonce every 200 ms. The input rate impacts the memory ofthe filter. For example, ifmeasurements were fed into the filter at a rate ofonce every I 00 ms then the maximum value on the x-axis ofFigure 333 would be 10 seconds rather than 20 seconds. 3GPP TS 38.331 specifics that the filter impulse response· is defined by an input rate whic:h equals one intra-frequency Layer I measurement period as specified by TS 38.133, assuming non-DRX operation * An actual implementation may use a different input rate, but in that case the implementation must also ensure that th<! impulse response remains unchanged relative to that specified by 3GPP * Filtering is applied in the same domain as the measurements, e.g. filtering is applied in dB for RSRQ and SINR measurements, and in * dBm for RSRP measurements 3GPP References: TS 38.331, TS 38.133 401

sG NR in BULLETS 11.3 EVENT Al * Event Al is triggered when the serving cell becomes better than a threshold: M'easserv - Hyst > Threshold * Event Al is subsequently cancelled if the following condition is satisfied: Measserv + Hyst < Threshold * Event A I is typk:ally osed to cancel an ongoing mobility procedure. This may be required if a UE moves 1owards cell edge and triggers a mobility proccdore, but then subsequently moves back into good coverage before the mobility procedure has complelted * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * When using RSRP, the threshold can be configured with a value between -156 and -31 dBm. The value of the threshold 1s signalled using the mapping presented in Table 237 (using a signalled value of between O and 127) * When using RSRQ, the threshold can be configured with a value between -43 and 20 dB. The value of the threshold is signalled using the mapping presented in Table 242 (using a signalled value of between O and 127) * When using SINR, the threshold can be configured with a value between -23 and 40 dB. The value of the threshold is signalled using the mapping presented in Table 243 (using a signalled value of between O and 127) * A time-to-trigger can be configured from the set {O, 40, 64, 80, 100, 128, 160, 256,320. 480,512, 640, I 024, 1280. 25,60, 5120} ms 11.4 EVE:NT A2 * Event A2 is triggered when the serving cell becomes worse than a threshold: Meassern + 1/yst < Threshold * Event A2 is subsequently cancelled if the following condition is satisfied: Measserv - f-lyst > Threshold * Event A1. is typically used to trigger a mobility procedure when a UE moves towards cell edge. Event A2 docs not involve any neighbour cell measurements so it may be used to trigger a blind mobility procedure. Alternatively, it may be used to trigger a set of neighbour cell measurements which can then be used for a measurement based mobility procedorc. Por example, the Base Station may configure measurement gaps and inter-frequency or inter-system measurements after Event A2 has been triggered. This approach means that the UE only needs to complete the inter-frequency/inter-system measurements whe11 coverage conditions are relatively poor and there is a high probability that a handover will be required * The hysteresis can be configured with a value between O and 15 dB. with 0.5 dB steps (signalled value between O and 30) * When using RSRP,the threshold can be configured with a value between -156 and -31 dBm. The value of the tbrcsho Id is signalled using the mapping presented in Table 237 (using a signalled value of between O and 127) * When using RSRQ, the threshold can be configured with a value between -43 and 20 dB. The value of the threshold is signalled using the mapping presented in Table 242 (using a signalled value ofbetween O and 127) * sn-rR,When using the threshold can be configured with a value between -23 and 40 dB. The value of the threshold is signalled using the mapping presented in Table 243 (using a signalled value of between O and 127) * A time-to-trigg,!r can be configured from the set {O, 40, 64, 80, 100, 128, 160, 256,320,480. 512, 640, I 024, 1280, 2560, 5120} ms 402

5G NR in BULLETS 11.5 EVENTA3 * Event A3 is triggered when a neighbouring cell becomes better than a special cell by an offact (a special cell is the primary serving cell of either the Master Cell Group (MCG) or Secondary Cell Group (SCG)). The offset can be either positive or negative. The event is triggered when the following condition is satisfied: Measneigh + 0neigh,freq + 0ne,gh,cell - Hyst > M'eassp + 0sp.freq + 0sp,cell + Offset * Event A3 is subsequently cancelled if the following condition is satisfied: Measneigh + 0neigh,freq + 0neigh,cell + Hyst < M'eassp + 0sp.freq + 0sp,cell + Offset * Event A3 is typically used for intra-frequency or inter-frequency handover procedures. A UE may be configured with measurement gaps and an Event A.3 for inter-frequency handover after an Event A2 bas triggered. Event A3 provides a handover triggering mechanism based upon relative measurement results,e.g. it can be configured to trigger when the RSRP of a neighbouring cell is stronger than the RSRP ofa special cell * Both the neighbour and special cell can have frequency specific and cell specific offsets applied to their measurements. Each of these offsets can be configured with values between -24 and +24 dB * The additional Offset added to the special cell measurement can be configured with a value between - I 5 and+ 15 dB, with 0.5 dB steps (signalled value between -30 and 30) * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * A time-to-trigger can be configured from the set (0, 40, 64, 80, I OOI, 128, 160, 256, 320, 480, 512, 640, I 024, 1280, 2560, 5120} ms 11.6 EVENTA4 * Event A.4 is triggered when a neighbouring cell becomes better than a threshold: Measneigh + 011e,gh,freq + 0neigh,cell - Hyst > Threshold * Event A4 is subsequently cancelled if the following condition is satisfied: Measneigl, + 0neigh,freq + 0neigh,cell + Hyst < Threshold * Event A4 can be used for mobility procedures which do not have a dependence upon the coverage of the current serving cell. For example, load balancing procedures take the decision to move a UE away from the current serving cell due to load conditions rather than radio conditions. In this case, the UE only needs to verify that the candidate target cell provides adequate covernge * The neighbour cell can have frequency specific and cell specific offsets applied to its measurements. Both offsets can be configured with values between -24 and +24 dB * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * When using RSRP, the threshold can be configured with a value be·twcen -156 and -31 dBm. The value of the threshold is signalled using the mapping presented in Table 237 (using a signalled value of between O and 127) * When using RSRQ, the threshold can be configured with a value between -43 and 20 dB. The value of the threshold is signalled using the mapping presented in Table 242 (using a signalled value ofbetween O and 127) * When using SINR, the threshold can be configured with a value between -23 and 40 dB. The value of the threshold is signalled using * the mapping presented in Table 243 (using a signalled value of between O and 127) A time-to-trigger can be configured from the set {O, 40, 64, 80, I 00, 128, 160,256,320,480, 512, 640, 1024, 1280, 2560, 5120} ms

sG NR in BULLETS 11.7 EVENT As .,, Event AS is triggered when a special cell becomes worse than thresholdI, while a neighbouring cell becomes better than thrcshold2. The event is triggered when both of the following conditions are satisfied: Meassp + Hyst < Thresholdl Measneigh + Oneigh,f,·eq + Dneigh.cell - Hyst > Threshold2 * Event AS is subsequently cancelled ifeither of the following conditions are satisfied: Meas5p - Hyst > Thresholdl MeaSneigh. + Oneigh.,freq + Dneigh,cell + Hyst < Threshold2 * Event AS is typically used for intra-frequency or inter-frequency handover procedures. A VE may be configured with measurement gaps and an Event AS for inter-frequency handover after an Event /1.2 has triggered. Event AS provides a handover triggering mechanism based upon absolute measurement results. It can be used to trigger a time critical handover when a current special cell * becomes weak and it is necessary to change towards another cell which may not satisfy the criteria for an event /1.3 handover The neighbour cell can have frequency specific and cell specific offsets applied to its measurements. Both offsets can be configured with a value between -24 and +24 dB * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * When using RSRP, the thresholds can be configured with values between -156 and -31 dBm. The value of the threshold is signalled using the mapping presented in Table 237 (using a signalled value of between O and 127) * When using RSRQ, the thresholds can be configured with values between -43 and 20 dB. The value of the threshold is signalled using the mapping presented in Table 242 (using a signalled value of between O and 127) * When using SINR,the thresholds can be configured with values between -23 and 40 dB. The value of the threshold is signalled using the mapping presented in Table 243 (using a signalled value of between O and 127) * A time-to-trigger can be configured from the set {O,40. 64. 80. I 00, 128. 160, 256, 320, 480, 512, 640, I024, 1280, 2560, 5120} ms 11.8 EVENT A6 * Event A6 is triggered when a neighbouring cell becomes better than a secondary cell by an offset. The offset can be either positive or negative. This measurement reporting event is applicable to Carrier Aggregation, i.e. connections which have secondary serving cells in addition to a primary serving cell * Event A6 is triggered when the following condition is true: MeaSneigh + Oneigh,cell - Hyst > MeaSsec + Osec,cell + Offset * Event A6 is subsequently cancelled if the following condition is satisfied: Measneigh + Oneigh,cell + J-lyst < Meassec + Osec,cell + Offset * Event /1.6 is typically used for secondary cell swap procedures. It may be necessary to swap the secondary cell if the pnmary and secondary cell carriers use different antenna with different azimuths. This can lead to changes in the best secondary cell as a UE moves within the coverage of the primary serving cell * In this case, a frequency specific offset is not included because both the neighbour and secondary serving cell arc on the same carrier, i.e. the offset would be the same for both cells and would have no impact * Both the neighbour and secondary serving cells can have cell specific offsets applied to their measurements. Each of these offsets can be configured with a value between -24 and+24 dB * The additional Offset added to the secondary serving cell measurement can be configured with a value between -15 and+15 dB,with 0.5 dB steps (signalled value between -30 and 30) * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * I\\ time-to-trigger can be configured from the set {O, 40, 64. 80, I 00, 128, 160,256,320,480,512, 640, I024, 1280. 2560,5120} ms 404

5G NR in BULLETS 11.9 EVENTB1 * Event B 1 is triggered when a neighbouring inter-system cell becomes better than a threshold: Measne(qh + Oneigh,freq + oneigh,cell - Hyst > Threshold * Event B l is subsequently cancelled if the following condition is satisfied: Measneigh + O,wigh.freq + Oneigh,cell + Hyst < Threshold * Event Bl can be used for inter-system mobility procedures which do not have a dependence upon the coverage ofthe current serving cell. For example,load balancing procedures take the decision to move a UE away from NR due to load conditions rather than radio conditions. In this case, the UE only needs to verify that the candidate target cell provides adequate coverage * The release 15 version of the 3GPP specifications only supports inter-system mobility towards LTE. This means that the neighbouring cell measurements can be based upon RSRP, RSRQ or STNR * The ueighbounng LTE cell can have frequency specific and cell specific offsets applied to its measurements. Both offsets can be configured with a value between -24 and +24 dB * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * When using LTE RSRP, the threshold can be configured with a value between -140 and -44 dBm. The value of the threshold is signalled using the mapping specified in 3GPP TS 36.133 (using a signalled value of between O and 97) * When using LTE RSRQ, the threshold can be configured with a value between -19.5 and -3 dB. The value of the threshold is signalled * using the mapping specified in 3GPP TS 36.133 (using a signalled value of between O and 34) When using LTE SINR, the threshold can be configured with a value between -23 and 40 dB. The value of the threshold is signalled using the mapping specified in 3GPP TS 36.133 (using a signall,ed value of between O and 127) * A time-to-trigger can be configured from the set (0, 40, 64, 80, I 00. 128, 160,256,320,480, 512, 640, I 024, 1280, 2560, 5120} ms 11.10 EVENT B2 * Event 112 is triggered when a primary serving cell becomes worse than threshold!, while a neighbouring inter-system cell becomes better than threshold2. The event is triggered when both ofthe following conditions arc satisfied: Measpcell + Hyst < Thresholdl Measne,gh + One,gh,freq + One,gh,cell - Hyst > Threshold2 __. Event 132 is subsequently cancelled if either of the following conditions are satistied: Measpcell - Hyst > Thresholdl Measneigh + Oneigh.freq + Oneigh,cell + Hyst < Threshold2 * Event B2 can be used to trigger inter-system mobility procedures when the primary serving cell becomes weak. Inter-system neighbour cell measurements arc used to ensure that the target cell provide.s adequate coverage * The release 15 version of the 3GPP specifications only supports mtcr-systcm mobility towards LTE. This means that the neighbouring cell measurements can be based upon RSRP, RSRQ or SINR * The neighbour cell can have frequency specific and cell spi.:citic offsets applied to its measurements. Both offsets can be configured with a value between -24 and +24 dB * The hysteresis can be configured with a value between O and 15 dB, with 0.5 dB steps (signalled value between O and 30) * When using NR RSRP. threshold I can be configured with a value between -156 and -31 dBm. When using LTE RSRP, thrcshold2 can * be configured with a value between -140 and -44 dllm When using NR RSRQ, threshold I can be configured with a value between -43 and 20 dB. When using LTE RSRQ, thrcshold2 can be configured with a value between -19.5 and -3 dB * When using NR SINR, thresholdI can be configured with a value between -23 and 40 dB. When using LTE STNR, threshold2 can be * configured with a value between -23 and 40 dB I\\. time-to-trigger can be configured from the set {O. 40. 64. 80, I 00, 128,160,256,320,480,512, 640, I 024, 1280, 2560, 5 I 20f ms

5G NR in BULLETS 12 IDLE MODE PROCEDURES 12.1 PLMN SELECTION * The UE is responsible for selecting a Public Land Mobile Network (PLMN) for subsequent cell selection. A PLMN ts identified by its PLMN identity broadcast within System Information Block I (SIB: I). A single cell can belong to multiple PLMN so SfB 1 may broadcast a list ofPLMN identities * The UE Non-Access Stratum (NAS) layer can request the UE Access Stratum (AS) layer to report available PLMN: o the UE scans all RF channels within its supported frequency bands o the UE searches for the strongest cell on each carrier and reads the system information to identity the PLMN o PLMN are reported to the NAS as high quality if their RSRP �-110 dBm. ln this case, the measured RSRP value is not reported to the NAS layer so high quality PLMN arc not differentiated by their signal strengths o PLMN which do not satisfy the high quality criteria are reported to the NAS together with their RSRP measurement o UE can optimise the PLMN search procedure using stored information, e.g. carrier frequencies and cell parameters o the NAS layer can stop the search at any time, e.g. after finding the home PLMN * The NAS layer is responsible for selecting a PLMN from the list o,freported PLMN. The NAS layer uses information from the USJM to help with PLMN selection: o International Mobile Subscriber Identity (IMS!): defines the Home PLMN (HPLMN) o HPLMN Selector with Access Technology: defines the priority ofeach technology associated with the HPLMN o User Controlled PLMN Selector with Access Technology: allows the end-user to prioritise the PLMN and technology o Operator Controlled PLMN Selector with Access Technology: allows the operator to prioritise the PLMN and access technology o Forbidden PLMNs: defines PLMN which the UE does not au1tomatically attempt to access. PLMN are added to the list of Forbidden PLNM when the network rejects a Registration Request using a cause value 'PLMN not allowed' or 'Serving network not authorized' o Equivalent HPLMN (EHPLMN): defines a set ofPLMN which are treated as equivalent to the PLMN with which the UE is registering. This list can be updated or deleted by the network during the registration procedure * The PLMN can be selected either automatically or manually * In the case ofautomatic selection, the UE selects the PLMN and a.cccss technology using the following order of priority: i) HPLMN (ifEHPLMN list is not available) or the highest priority EHPLMN (ifEHPLMN list is available) ii) PLMN and access technology combinations defined within the User Controlled PLMN Selector iii) PLMN and access technology combinations defined within tlhc Operator Controlled PLMN Selector iv) other PLMN reported as high quality PLMN, selected in random order v) other PLMN selected in order ofdecreasing signal quality * The UE searches all supported access technologies before selecting a PLMN when using steps iv) and v) * In the case ofmanual selection, the UE presents the end-user with the available PLMN, listing them in the followmg order: i) HPLMN or Equivalent HPLMN (EHPLMN) ii) PLMN and access technology combinations defined within the User Controlled PLMN Selector iii) PLMN and access technology combinations defined within the Operator Controlled PLMN Selector iv) other PLMN reported as high quality PLMN, selected in random order v) other PLMN selected in order ofdecreasing signal quality The end-user is then able to select which PLMN the VE should attempt to access * 3GPP reforences: TS 38.304, TS 23.122, TS 24.50 I, TS 31.102 406

5G NR in BULLETS 12.2 CELL SELECTION * Cell selection is used to identify a cell for the UE to camp on. It is applicable after a UE 1s switched-on, after a UE leaves RRC Connected mode and after a lJE returns to an area of coverage * Initial cell selection does not rely upon any stored information. TheUE scans all RF channels within its supported frequency bands. Scanning is based upon the synchronisation raster described in section 2.5.2. This raster is relatively coarse to reduce the number of candidate carrier frequencies and thus reduce the delay generated by band scanning. The lJE searches for one or more SS/PBCl I Blocks at each candidate carrier frequency (each candidate carrier frequency has a Global Synchronisation Channel Number (GSCN)). After finding one or more SS/PBCH Blocks at a specific GSCN, the lJE identifies the strongest cell and proceeds to decode the Sysicm Information. It is possible that the UE discovers a set ofSS/PBCH Blocks which do not have any associated System Information. In that case, the PBCH can provide information which directs the UE towards another set ofSS/PBCH Blocks. This information is extracted from the subcarrier offset (kssR) described in section 6.1 * AUE is permitted to use stored information to support the cell selection procedure. This can include carrier frequencies which the lJE has previously camped on. It can also include cell parameters from previously received measurement control information or previously detected cells. In the case ofcell selection after leaving RRC Connected mode, the Base Station can use the RRCRe/ease message to direct the lJE towards a specific carrier. A lJE uses the initial cell selection procedure ifcell selection based upon stored information is unsuccessful * AUE attempts to camp on a 'suitable' cell during the cell selection procedure. Ifthe UE fails to camp on a 'suitable' cell then the UE will attempt to camp on an 'acceptable' cell. When camped on a 'suitable' cell, the lJE can register with the network and access its normal set of services. When camped on an 'acceptable' cell, the lJE is restricted to limited services, i.e. emergency calls and reception of Public Warning System (PWS) notifications * A 'suitable' cell is defined as a cell which: o is not barred o belongs to the PLMN selected by the NAS layer, the registered PLMN or an Equivalent PLMN o belongs to at least one Tracking Area which is not forbidden o satisfies the cell selection criteria * The Master Information Block (MIB) uses the eel/Barred !lag to indicate whether or not the cell is barred. Ifthe cell is barred then the UE is not permitted to camp on that cell and the UE has to wait 300 seconds before re-checking the MIB to determine whether or not the cell remains barred. If a cell is barred, the inlraFreqReselection flag within the MIB indicates whether or not the UE is permitted to camp on another cell belonging to the same carrier frequency * SIB! is known as the 'Remaining Minimum System Information' (RMS!). It provides a list of PLMN Identities and specifies a Tracking Arca Code for each PLMN. It also provides the set ofparameters which define the cell selection criteria * 3GPP TS 38.304 specifics the cell selection criteria ('S' criteria) as: Srxlev > 0 AND Squal > 0 where, Srxlev = Qrxlevmeas - (Qrxlevmin + Qrxlevminof[set) - Pcompensation- Qoffsetremp Squal = Qqualmeas - (Qqualmin + Qqualminoffset) - Qoffsetiemp * Qrx/evmeas is the SS-RSRP measured by the UE. In the case ofcell selection, 3GPP docs not specify the rules for deriving a cell level measurement from a set ofbeam level measurements. Instead, this derivation is left to the UE implementation. Figure 334 illustrates some example solutions for deriving the cell level measurement from a set ofbeam level measurements. The first example assumes that the cell level measurement is based upon only the strongest beam. In this case, cell selection is effectively completed using beam level m,easurements rather than cell level measurements. The second example assumes that the eell levcl measurement is derived from the 'x' strongest beams, whereas the third example assumes that the cell level measurement is derived from all beams which exceed a specific threshold * Qrx/evmin defines the minimum RSRP threshold for the cell. It is broadcast by SIBI and can be configured with a value between -140 and -44 dBm, using a step size of2 dBm. !Is value defines the Idle Mode coverage area of the cell. A high value will restrict the coverage area, whereas a low value may lead to failed connection setup attempts at cell edge. An initial value can be based upon the maximum allowed path loss calculated from a set ofuplink and downlink link budgets. Subsequent field trials can be used for * optimisation Qxr levminojfsel is included within the 'S' criteria when a UE is completing a periodic search for a higher priority PLMN while camped on a visited PLMN. The value ofQ1:clevminojJ�et is always positive so the cell selection criteria becomes more stringent. The objective ofusing this offset is to help reduce the potential for ping-pong

sG NR in BULLETS Ce# selection based upon average of Cel selection based upon the average ·x· strongest beams of aH beams above specific threshold CeH selection based upon the strongest beam 0 Uo o Uo o Figure 334 - Examples of deriving a cell level measurement from a set of beam level measurements * ?compensation is used to adjust the value of Qrxlevmin according to the UE transmit power capability. In a simple deployment scenario, ?compensation - MAX(PFMAx1 Prowi,RCLASS, 0), where Pr-MAXI is the maximum allowed uplink transmit power within the cell (broadcast within SrB I), and ProwERC1.Ass is the maximum transmit power capability of the UE. It is assumed that the value of Qrx/evmin has been configured based upon a UE transmit power equal to PEMAXI- UE which have a transmit power capability less than PEMAXI may not be able to establish a connection at cell edge. In that case, ?compensation is used to make the 'S' criteria more * stringent to avoid those UE camping on the cell at locations where they cannot establish a connection In a more complex deployment scenario, SIBI can broadcast multiple maximum UE transmit powers.The primary maximum UE transmit power is 'PEMAXI' which is used for the simple deployment scenario and is included within thefrequencylnfoUL section of SIBI . Additional maximum UE transmit powers can be broadcast within an instance of nr-NS-PmaxList. Each additional maximum UE transmit power is linked to an additional spectrum emissions requirement, i.e. the UE is permitted to use another maximum transmit power if it is able to achieve the specified spectrum emissions requirement.The UE selects the first pair of values within the list which arc supported and sets 'PFMAx2' equal to the corresponding additional maximum UE transmit power. The UE then calculates ?compensation = MJ\\X(PtMAXI ProWl'RCLASS, 0} MfN(PEMAX2, ProwERCLAss} + MIN(PEMAXI, ProwFRCLAss).This more complex deployment scenario can lead to a negative value for ?compensation which increases the cell range. For example, if ProWERCLASS = 23 dBm, while PtMAXI = 15 dBm and PEMAX2 = 18 dBm, then ?compensation = MJ\\X(I S 23, 0)- MIN(l8, 23) + MrN(l5, 23) = 0 18 + 15 = -3 dB, i.e. the 'S' criteria is relaxed by 3 dB and the UE is pcnnitted to camp on the cell outside the nonnal Qrxlevmin * QojJfet,emp is defined by the value of connEstFai/Offse1 within the conn£s1Fai/11reC011/rol section of SIB I. This temporary offset is applied if the UE experiences repetitive connection setup failures caused by T300 expiring, i.e. the UE docs not receive an RRCSelllp nor RRCRejecl message after sending an RRCSetupRequesl. The temporary offset is applied for a period of time 'T' ifT300 expires for 'N' consecutive connection setup attempts, where 'T' - connEstFai/0.ffsetValidity and 'N' - connEstFailCount. The temporary offset makes the 'S' criteria more stringent so the UE is more likely to start searching for another cell * Qqualmeas is the SS-RSRQ measured by the UE. Similar to Qrxlevmeas, the UE is responsible for deriving a cell level measurement from the set of beam level measurements (assuming the UE detects multiple beams) * Qqualmin defines the minimum RSRQ threshold for the cell. It can be configured with a value between -43 and -12 dB, using a step size of I dB. A high value will restrict the coverage area, whereas a low value may lead to failed connection setup attempts. Qqualmin is optional within SIB I so it is not mandatory to use an RSRQ threshold during cell selection. The UE assumes a value of negative infinity for Qqualmin if it is excluded from SIBI, i.e. ensuring that the UE always passes the Squat part of the 'S' criteria. * Qqualminoff.set is included within the 'S' criteria when a UE is completing a periodic search for a higher priority PLMN while camped on a visited PLMN. The value of Qqualminoffsel is always positive so the cell selection criteria becomes more stringent. The objective of using this offset is to help reduce the potential for ping-pong * 3GPP reference: TS 38.304, TS 38.331 408

5G NR in BULLETS 12.3 CELL RESELECTION * Cell reselection is the mobility solution for lJE in the RRC Idle and RRC Inactive states * In the case ofRRC Idle, a UE can complete cell reselections without informing the network, as Jong as the VE remains within a registered Tracking Arca. The UE is responsible for acquiring SIB I after each cell reselection to determine whether or not the UE remains located within a registered Tracking Area. The lJE completes a NAS: Registration procedure with the A.MF after moving into an unregistered Tracking Arca * In the case ofRRC Inactive. a UE can complete cell reselections without informing the network, as long as the UE remains within the allocated RAN Notification Area (RNA). A Base Station allocates a RAN Notification Area when moving a UE from RRC Connected to RRC inactive (using the RRCRelease message). The UE is responsible for acquiring SIB! after each cell reselection to determine whether or not the UE remains located within the allocated RAN Notification Area. The VE completes an RRC: Resume procedure with cause value 'ma-Update' after moving outside the allocated RAN Notification Area 12.3.1 ABSOLUTE PRIORITIES * Absolute Priorities influence the network layer select.ed by a UE during cell reselection, i.e. Absolute Priorities are used to differentiate * network layers, rather than cells belonging to lhe same layer In general, Absolute Priorities can be allocated to network layers belonging to GSM, UMTS, CDMA2000, LTE and NR. For example, the LTE system can broadcast priorities for these network layers within S1B6 (UMTS), SIB7 (GSM), SIB8 (CDMA2000), SIB3/SIB5 (LTE) and SIB24 (NR) * The release 15 version ofNR is restricted to supporting intra-frequency and inter-frequency cell reselection within the NR network, and inter-system cell reselection towards LTE. * Absolute Priorities are broadcast within the following NR system information: o SIB2 - absolute priority for the current NR carrier o SIB4 - absolute priorities for inter-frequency NR carriers o SIB5 - absolute priorities for inter-system LTE carriers * Absolute Priorities can also be signalled directly to individual UE within an RRCRelease message, i.e. when UE arc moving to RRC Idle or RRC Inactive. These priorities do not need to be consistent with those broadcast within the SfB. For example, the STB may prioritise an NR carrier while the RRCRe/ease message may prioritise an LTE carrier. The priorities within the RRCRe/ease message can be used for load balancing purposes. For example, 'x' percent ofVE can be allocated a first set ofpriorities which move those UE to carrier I, while 'y' percent ofUE can be allocated a second set ofpriorities which move those UE to carrier 2 * Timer T320 is provided in combination with the Absolute Priorities within an RRCRelease message. T320 can be configured with values ranging from 5 minutes to 3 hours. A UE discards the priorities provided by the RRCRe/ease message when T320 expires. These priorities arc also discarded when the UE enters RRC Connected mode. Jn this case, the UE relics upon receiving another set of priorities within the next RRCRelease message, or reverting to using the priorities within the System Information * The value and current state ofT320 is carried across technologies so T320 will continue running ifa UE completes a cell reselection from NR to LTE. Similarly, ifthe UE receives a set ofAbsolute Priorities and a value for T320 within an RRCConnectionRelease message on LTE, then the value ofT320 and the set ofpriorities can be carried across to NR. Jn the case ofUMTS, the equivalent timer is known as T322 * NR allows Absolute Priorities to be configured using the pair ofinformation clements presented in Table 248. These information clements allow up to 40 priority levels to be configured, ranging from Oto 7.8. Integer values are configured by excluding the second information clement. Earlier versions oflegacy technologies were limited to using the set of8 integer priorities. The concept ofsub­ priority was introduced within the release 13 version ofthe 3GPP specifications to cater for the increasing number oflayers within live network deployments CellReselectionPrionty 0 to 7 CcllRcsclcctionSubPriority 0.2, 0.4, 0.6, 0.8 Table 248- Configuration of Absolute Priority * Inter-frequency layers belonging to NR can be configured with equal priorities but inter-system layers belonging to difef rent technologies arc not permitted to use the same priority * 3GPP references: TS 38.304, TS 38.331 409

5G NR in BULLETS 12.3.2 TRIGGERING MEASUREMENTS * Measurement rules are intended to reduce the quantity of neighbour cell measurements completed by a UE. This is done by triggering measurements only when necessary. Reducing the quantity of meas.urements helps to increase the UTI battery life * AUE docs not have to complete intra-frequency neighbouring cell measurements ifbulh uf the following conditions an� satisfied: Srxlev > SmtraSearchP AND S,qual > SintraSearchQ * /1. UE has to complete intra-frequency neighbouring cell measurements if either condition is not satisfied. * These conditions mean that the UTI docs nut have to complete intra-frequency measurements when the coverage conditions are relatively good. SintrasearchP and SintrasearchQ are both broadcast by Sf82. rt is not mandatory to broadcast a value for SinlrasearchQ. A default value ofO dB is assumed ifSintrasearchQ is excluded from SJB2. The default value means that Squat is always greater than SintrasearchQ * SintrasearchP can be configured with a value between O and 62 dB, using a step size of2 dB. In contrast, SintrasearchQ can be configured with a value between O and 31 dB, using a step size of I dB * AUE always completes measurements for cell reselection towards a higher priority inter-frequency or inter-system layer * AUE docs not have to complete measurements for cell reselection towards an equal or lower priority inter-frequency layer if both of th!! following conditions are satisfied. Similarly, A VE does not have to complete measurements for cell reselection towards a lower priority inter-system layer if both of the following conditions are satisfied: Srxlev > Snon/ntrasearchP AND Squal > SnonlntrnSearchQ * AUE has to complete inter-frequency/inter-system measurements if either condition is not satis[ied * SnonintrasearchP and SnonintrasearchQ arc both broadcast by SIB2. Roth information clements arc optional. A default value of infinity is assumed for SnonintrasearchP if it is excluded, whereas a default value ofO dB is assumed for SnonimrasearchQ if it is excluded. This means that measurements are always required if Sn,rmintrasearchP is excluded from SIB2 (assuming equal or lower priority inter-frequency layers or lower priority inter-system layers exist) * SnonintrasearchP can be configured with a value between O and 62 dB, using a step size of 2 dB. In contrast, SnonintrasearchQ can be configured with a value between O and 31 dB, using a step size of I dB * Figure 335 illustrates the general concept of triggering neighbour cell measurements based upon Srxlev. Ignoring the impact of offsets and Pcompensaton, Srxlev is O dB when the measured RSRP is equal to Qrxtevmin (the equation for Srxlev is presented in section 12.2). The value of Srxlev increases as the measured RSRP increases relative to Qrxlevmin Sr>r,/ev = �n<l�v = Srlfl.ev= 0 Higher Priority 5intrag:arrhP SnqnivJm�eQr1;J1P Measure Inter-Frequency Measure Measure & Inter-System Layers Measure Measure Intra-Frequency Layers ---------- Qrx.lf:Jlrnjp + Measure Equal or Lower Priority SintraseqrchP Qrxl1:vrr1./ri Inter-Frequency Layers QrxJevmin + Lawer Priority S.nQJJinl[a�an;fJP Inter-System Layers Figure 335 - Triggering of measurements based upon Srxlcv * The equivalent figure for Squat is the same but Qrxlevmin is replaced by Qqualmin and SintrasearchPISnoninlrasearchP arc replaced by SintrasearchQ!SnonintrasearchQ * 3GPP references: TS 38.304, TS 38.331 410

5G NR in BULLETS 12.3.3 MOBILITY STATES * Mobility states are used to scale the time-to-trigger used for cell reselection (Trese/ection). The scaling factor reduces the timc-to­ trigger for high mobility states to allow cell reselection to complete more rapidly * In addition, mobility states are used to scale the hysteresis applied to serving cell measurements when ranking intra-frequency and equal priority inter-frequency neighbours. The scaling factor reduces the hysteresis for high mobility states to allow cell reselection to complete more rapidly * 3GPP TS 38.304 specifies normal, medium and high mobility states. The high and medium mobility states are applicable ifthe optional speedStateReselectionPars parameter set is broadcast by SIB2. This parameter set is presented in Table 249 speedStateReselectionPars mobilityStaleParamclers I-Evaluation 30, 60, 120, 180, 240 s q-HystSF t-Hys!Normal 30, 60, 120, 180, 240 s n-CcllChangcMcdium I to 16 n-CellChangcHigh I to 16 sf-Medium -6, -4, -2, 0 dB sf-High -6, -4, -2, 0 dB Table 249-Speed state reselection parameters within S182 * A lJE has normal mobility by default. * AUE detects high mobility ifthe number ofcell reselections during a time window 't-Evaluation' is greater than 'n-Cel/ChangeHigh' * A lJE detects medium mobility ifthe number ofcell rcsclcctions during a time window ·t-Eva/ualion' is greater than or equal to * 'n-Cel!ChangeMedium' but less than or equal to 'n-Cel/ChangeHigh' A lJE returns from the high or medium mobility states to the normal mobility state ifthe criteria for neither medium nor high mobility are detected during a time period 't-HystNormal' * A lJE excludes ping-pongs between two cells when counting the number ofcell reselections * )fa lJE is in the high or medium mobility state then speed dependent scaling rules are applied * Ifhigh mobility is detected o •4:High' from 'q-HystSF' in STB2 is added to the serving cell value for Qhyst (applicable to intra-frequency and equal priority inter-frequency cell reselection) o 't-Rese/ectionNR' (SIB2) is multiplied by 'sf-High' from 't-ReselectionNR-SF' (SIB2) for intra-frequency cell reselection o 't-ReselectionNR' (SIB4) is multiplied by 'sf-High' from 't-ReseleclionNR-SF' (SIB4) for inter-frequency cell reselection o 't-ReselectionEUTRA' (SIB4) is multiplied by 'sf-High' from 't-ReselectionEUTRA-SF' (SIB5) for inter-system cell reselection * The same rules arc applied for medium mobility but 'sf-High' is replaced by 's-f Medium' * 'sf-high' and 'sf-medium' for 'Qhyst' can be configured with values of-6, -4, -2 and 0 dB, i.e. they tend to decrease the value ofQhyst to make cell reselection faster for lJE with increased mobility * 'sf-high' and 'sf-medium' for 'Treseleclion' can be configured with values of0.25, 0.5, 0.75 and 1.0, i.e. they tend to decrease Trese/ection to make cell reselection faster for UE with increased mobility * When Trese/ection is scaled, the result is rounded up to the nearest second * 3GPP references: TS 38.304, TS 38.331 411

has previously had setup attempt failures on the neighbouring cell and the connEstFai/OffeetVafidity timer is still running -. IfrangeToBestCell is notbroadca�t by SlB2 then cell reselection is completed ifa neighbouring cell is ranked higher than the current serving cell during a time period defined by Treselection, and ifmore than I second has passed since the lJE camped on the current serving cell. Treselection for intra-frequency cells is broadcastin SIB2, whereas Treselection for inter-frequency cells is broadcast in SIB4 * IfrangeToBestCell is broadcast by SIB2 then the cell reselection procedure accounts for both the ranking and the ·beam level' measurements. This principle is illustrated in Figure 336. The UE identifies thehighest ranked cell and then defines a threshold which is rangeToBestCell below the ranking ofthat highest ranked cell. J\\ny cells which have a ranking below that threshold arc then excluded. For the remaining cells, the UE counts the number ofbeams which exceed absThreshSS-BlocksConsolidation. The cell with the highest countis then categorised as the best cell. Cell reselection is completed ifa neighbouring cell has been categorised as the best cell during a time period defined by Treselection, and ifmore than I second has passed since the UE camped on the current serving cell. For the example illustrated in Figure 336, cell 2 is categorised as the best cell because its ranking is greater than the rangeToBestCell threshold and it has 2 beams which exceed absThreshSS-BlocksConsolidation Cell 1 - Highestrankedcell but Cell 2- 2nd highestranked cell Cell 3- Rankingis outside only 1 beam above threshold but 2 beams above threshold 'rangeToBestCell' i ~~: ~ ~ l$' en Q ::: Ce!/ level ranking oO Oo I D Cell level r a n fng absThreshSS­j:> Beam measurements BlocksConso/1dation ' ~ Cell level ra~king i oO Oo y n Oo Beam measurements Beam measurements l [ I Figure 336 - Ranking ofcells when rangeTo/Jes/Cellis broadcast by SIB2 412

sG NR in BULLETS 12.3.4 RESELECTION INTRA-FREQUENCYAND EQUAL PRIORITY INTER-FREQUENCY * Ranking is applicable to intra-fi-cqucncy cell reselection and equal priority inter-fi-equcncy cell reselection. It is not applicable to inter­ system cell reselection because mtcr-systcm layers cannot be allocated an equal priority * The UE ranks all cells which satisfy the cell selection 'S' criteria presented in section I2.2. Ranking is completed using the 'R' criteria: Rs= Qmeas,s + Qhyst - Qoffsetcemp,s (calculated for the serving cell) Rn= Qmeas,n - Qoffset - Qoffsetcemp.1t (calculated for the neighbouring cell) * Ranking is always completed usingRSRP measurements. Rs and Rn arc calculated using 'cell level' measurements rather than ·beam level' measurements.The derivation of'ccll levcl' measurements fi-om 'beam level' measurements is described m section I 1.1 * Qhysl is broadcast within SIB2. In the case ofintra-frequency neighouring cells, QoJJ�et is defined by q-Qff.setCe/1 broadcast within SHB. In the case ofinter-fi-equency neighbouring cells, Qoff.ret is defined as the sum ofq-OjfsetCell and q-Q[f�etFreq broadcast within SIB4. Offsets which arc excluded from the SIB are assumed to have a value of0 dB * Cell specific offsets for intra-frequency cell reselection should be applied with care because they can lead to a UE camping on a cell which is not the 'normal' best server. In this case, the UE is likely to generate increased levels up uplink interference towards the 'normal' best server and may experience increasedlevels ofdownlink interference from the 'normal' best server * Qoff.rel,empis defined by the value ofconnEstFai/Offeet within the connEstFailureControl section ofS18I.This temporary offset is applied ifthe UE experiences repetitive connection setup failures caused byT300 expiring, i.e. the UE docs notreceive an RRCSetup nor RRCReject message after sending an RRCSetupRequest. The temporary offset is applied for a period oftime 'T' ifT300 expires for 'N' consecutive connection setup attempts, where 'T' connEstFailQl]ietValidity and 'N' = connEstFai/Co1111t. The temporary off.�et reduces the cell ranking so makes the cell less attractive * QoJ.se/1,mp,.,is applied ifthe lJE has had connection setup attempt failures on the serving cell, whereas Qo.ffset,,mp.nis applied ifthe UE

5G NR in BULLETS HIGHER PRIORI1Y INTER-FREQUENCY & INTER-SYSTEM * Cell reselection towards a higher priority layer can be based upon either RSRP measurements or RSRQ measurements. If threshServinglowQ is broadcast by SIB2 then the procedure is based upon RSRQ measurements. In that case, the UE moves to the higher priority layer ifthe following condition is satisfied for the target cell: [ Squaltarget > Threshx,HighQ * Squaltarget is calculated according to the cell selection 'S' criteria presented in section 12.2 * SIB4 broadcasts Threshx,HighQ for inter-frequency neighbours, whereas Sf85 broadcasts Threshx,HighQ for LTE inter-system neighbours. The value ofThreshx,HighQ can range from Oto 31 dB, with a step size ofI dB. Ignoring the impact ofany offsets, Threshx,HighQ defines a margin relative to Qqualmin, as shown in Figure 337 Target cell threshX-HlghQ 1 Source cell •----- Qquolmin Figure 337 - threshX-HighQ criteria for cell reselection towards a higher priority layer * IfthreshServinglowQ is not broadcast by SIB2 then the cell reselection procedure is based upon RSRP measurements. In that case, the lJE moves to the higher priority layer ifthe following condition is satisfied for the target cell: Srxlevtarget > Threshx,flighP * Srxlevcarget is calculated according to the cell selection 'S' criteria presented in section 12.2 * SIB4 broadcasts Threshx,HighP for inter-frequency neighbours, whereas S185 broadcasts Threshx.HighP for LTE inter-system neighbours. The value ofThreshx,HighP can range from Oto 62 dB, with a step size of2 dB. Ignoring the impact ofany offsets and Pcompensalion, Threshx.HighP defines a margin relative to Qrxlevmin. Figure 337 is applicable ifQqualmin is swapped with Qrxlevmin and Threshx,HighQ is swapped with Threshx,HighP * Cell reselection is completed ifa target neighbouring cell satisfies the criteria during a time period defined by Treseleclion, and ifmore than I second has passed since the UE camped on the current serving cell. The value ofTreseleclion is obtained from SIB4 when completing inter-frequency cell reselection, and from SIB5 when completing inter-system cell reselection LOWER PRIORI1Y INTER-FREQUENCY & INTER-SYSTEM * Cell reselection towards a lower priority layer can be based upon either RSRP measurements or RSRQ measurements. If threshServinglowQ is broadcast by SIB2 then the procedure is based upon RSRQ measurements. In that case, the UE moves to the lower priority layer ifboth ofthe following conditions are satisfied: Squalsource < Threshserving,LowQ (checked for the serving cell) Squalta,·get > Threshx,LowQ (checked for the neighbouring cell) * Squalsource and Squalcarget are calculated according to the cell selection 'S' criteria presented in section 12.2 * SIB4 broadcasts Threshx,LowQ for inter-frequency neighbours, whereas SIBS broadcasts Threshx,LowQ for LTE inter-system neighbours. The values ofboth Threshserving,LowQ and Threshx,LowQ can range from Oto 31 dB, with a step size of 1 dB. Ignoring the impact ofany offsets, these thresholds define margins relative to Qqualmin, as shown in Figure 338 413

sG NR in BULLETS Target cell - - threshX-iew.Q ~ i Source cell r------- I Qqualmm ----- --:-------\" threshServingLawQ : -----�: - Qq�almin Figure 338 - thre.,hX-LowQ and threshServin�LowQ criteria for cell reselection towards a lower priority layer * If threshServingLowQ 1s not broadcast by SIB2 then the cell reselection procedure is based upon RSRP measurements. In that case, the UE moves to the lower priority layer if both of the following conditions arc satisfied: SrxleVsource < Threshserving,LawP (checked for the serving cell) SrxleVtarget > Threshx,lowP (checked for the neighbouring eelI) * Srxlevsource and Srxlevtarget arc calculated according to the cell selection 'S' criteria presented in section 12.2 * SIB2 broadcasts Threshserving,LowP, whereas STB4 broadcasts Threshx,LowP for inter-frequency neighbours and SIB5 broadcasts Threshx,LowP for LTE inter-system neighbours. The value of both Threshserving,LowP and Threshx,LowP can range from Oto 62 dB, with a step size of 2 dB * Cell reselection is completed if the source and target neighbouring cell satisfy the criteria during a time period defined by Treselection, and if more than I second has passed since the UE camped on the current serving cell. The value of Treselection is obtained from SIB4 when completing inter-frequency cell reselection, and from SIB5 when completing inter-system cell reselection * 3GPP references: TS 38.304, TS 38.331 414

sG NR in BULLETS 12.4 PAGING 12.4.1 PROCEDURE * This section describes the 5G paging procedure which is applicable to Base Station architectures which allow the UE to camp on the 5G system in RRC Idle. For example, this section is applicable to the Standalone Base Station architecture 'option 2' which is based upon a SG Base Station connected to the 5G Core Network. The 5G paging procedure is not applicable to Non-Standalone Base Station architecture 'option 3' which is based upon a 4G anchor Base Station providing control plane connectivity to the 4G Core Network. ln that case, the UE camps on the 4G system in RRC Idle mode and the 4G paging procedure is applicable. The 4G and SG paging procedures arc very similar but there are some important differences, e.g. the 5G paging procedure does not allow a UE to be addressed using its rMSI * VE listen for paging messages while in RRC Idle and RRC Inactive. Paging messages allow the network to initiate mobile terminated connections. The Core Network is responsible for RRC Idle paging procedures, whereas the serving Base Station is responsible for RRC Inactive paging procedures. J\\n additional category ofpaging is applicable to UE in RRC Connected, RRC Idle and RRC Inactive. This additional category is applicable when there is a requirement to notify UE ofa change to the System Information or an incoming ETWS/CMJ\\S message. In these cases, the paging procedure docs not use NGAP nor RRC Paging messages. lnstead, the paging procedure uses only the payload of the PDCCH. Downlink Control Information (DCT) Format I_0 can include a 'Short Message' when the CRC bits are scrambled using the P-RNTI. This 'Short Message' can be used to indicate that System Information * has been updated and needs to be re-acquired or there is an incoming ETWS/CMAS message For a UE in RRC Idle, the AMF maintains a record ofthe UE location in terms ofits registered Tracking i\\rca(s). The UE triggers a NAS Registration procedure with cause value 'mobility registration updating' if it moves outside the registered Tracking Area(s). The UE does not update the network while moving within the registered Tracking Area(s). In general, this means that paging messages must be broadcast by all Base Stations belonging to the registered Tracking J\\rea(s). This tends to generate a relatively high paging * load, especially for large Traclcing Areas which capture a large number ofUE Specific Core Network implementations may make certain assumptions regarding the UE location. For example, ifa UE releases its connection from a specific Base Station and then a paging procedure is triggered 30 seconds later, there is a high probability that the UE bas remained within the coverage ofthe same Base Station. In this case, the AMF may send the paging message to only that single Base Station rather than all Base Stations within the registered Tracking J\\rea(s). Ifthe paging attempt is unsuccessful then the AMF can re-send the paging message using the full set ofBase Stations. This type ofsolution reduces paging load at the cost ofincreased * delay for UE which have moved to a different Base Station Figure 339 illustrates an AMF completing the paging procedure for a UE in RRC Idle. The UE uses Discontinuous Reception (DRX) to help conserve UE battery life while in RRC Idle, i.e. the UE receiver enters a sleep mode between periodic Paging Occasions. At each Paging Occasion, the VE scans for a PDCCH transmission which has its CRC scrambled by the P-RNTI. All UE share a common P­ RNTI value of'FFFE'. Downlink Control Information (DCI) Format I_0 is always used when allocating PDSCH resources for a Paging message. The UE determines its Paging Occasions using a combination ofinformation broadcast in STB I and its allocated SG­ S-TMSI. Paging Occasions are described in the next section � UE in RRC Idle 'IJ Base AMF NGAP: Paging Start lDRX Paging Occasion -I -Station lCycle Paging Occasion T3513 PDCCH with P-RNTI DRX RRC: Paging Cycle (PCCH/PCH/PDSCH) Random Access Procedure RRC Setup Request (CCCH/UL-SCH/PUSCH) RRC Setup (CCCH/DL-SCH/PDSCH) RRC Setup Complete/ '-\"SN�eGrAv�iPc:e�IRnietqi�aul eU�sEt M-es-sag-e/ ------\"\"'T5t305P13 Service Request (DCCH/UL-SCH/PUSCH) figure 339 - Paging procedure initiated by the Core Network for a UE in RRC Idle 415

5G NR in BULLETS * The AMF is responsible for providing 'UE Reachability' services for other Network Functions. For example, an SMS Function (SMSF) may have received an SMS addressed to a UE which is registered with the AMF. In that case, the SMSF requests the AMF to initiate the paging procedure before forwarding the SMS for delivery. Alternatively, a User Plane Function (UPF) may have received downlink data which is addressed to a UE currently in RRC Idle. In that case, the UPF notifies the SMF that downlink data has arrived and the SMF requests the AMF to initiate the Paging procedure. The UPF can subsequently forward the downlink data to the Base Station once the UE has entered RRC Connected and the Base Station has setup a GTP-U tunnel with the UPF * The AMF starts the T35I 3 timer when sending the NGAP: Paging message to a Base Station. This timer serves as a supervision timer for the Paging procedure. The AMF assumes that the paging procedure has failed ifT35I 3 expires before receiving a response from the UE. This may trigger the AMF to initiate a re-transmission of the Paging message * The NGAP: Paging message is presented in Table 250. Only the 'UE Paging Identity' and 'TA1 List for Paging' fields arc mandatory so the remaining fields may be excluded from the message NGAP: Paging UE Paging Identity 5G-S-TMSI AMF Set Identity & AMF Pointer & 5G-TMSI Paging DRX TAI List for Paging 32, 64, 128,256 Paging Priority UE Radio Capability for Pagmg SEQUENCE {1 to 16 instancesl Assistance Data for Paging Tracking Area Identity PLMN Id & Tracking Area Code (fAC) PagingOngm I, 2, 3, 4, 5, 6, 7, 8 Capability for NR List of Supported SEQUENCE {I to 1024 instances} NR Bands I to 1024 Capability for E-UTRA List of Supported SEQUENCE [ I to 64 instances} E-UTRA Bands I to 256 Recommended Cells SEQUENCE {I lo 16 instances} NG-RAN CG! ICHOICE NRCGI E-UTRA CG/ Time Stayed m Cell 0 to 4095 seconds Paging Atte•mpt lnfonnation Paging Allempt Count I to 16 ...Intended Number of Paging Attempt� I to 16 Next Pagi1Jg Area Scope Same, changed non-3PP Table 250- NGAP: Paging message * The Base Station uses the 'UE Paging Identity' to address the UE within the RRC: Paging message. This identity corresponds to a 5G­ S-TMSI which is a concatenation of the AMF Set Identity (10 bits), the AMF Pointer (6 bits) and the 5O-TMSI (32 bits). The 10 Least Significant Bits (LSB) of the 5O-TMSJ arc used to determine the Paging Frames and Paging Occasions for the UE. The AMI' is responsible for ensuring that the population ofUE are allocated 5G-TMS1 values which evenly distribute the UE across the set of Paging Frames and Paging Occasions. The 5O-S-TMSI is used instead of the IMSI when addressing the UE because it is a temporary identity. The use of a temporary identity helps to improve security by avoiding exposure of the permanent UE identity. In contrast, the SI AP: Paging message used by 40 allows the UE to be addressed by either its IMSI or S-TMSI * The 'Paging DRX' field can be included to ensure that the Base Station determines the correct DRX pattern being used by the UE. The Base Station broadcasts the Default DRX cycle duration within SIB I. The Base Station also provides this Default DRX cycle duration to the AMF during the NG interface setup procedure. The AMF may negotiate a UE specific DRX cycle during the NAS Registration procedure. This negotiation is transparent to the Base Station so the Base Station may not know the DRX cycle being used by the UE * The AMF can also use the 'Core Network Assistance Information' parameter structure to provide the Base Station with information regarding a UE specific DRX cycle. This parameter structure can be included within an NGAP: Initial Conte.xi Setup Request, UE Conle.xt Modification Request, Handover Request or Path Switch Request Acknowledge message * The 'Tracking Area Identity (TAI) List' is included to ensure that the Base Station broadcasts the RRC: Paging message using the appropriate cells. In many cases, all cells belonging to a Base StatJOn will belong to the same Tracking Area. However, there are also deployment scenarios where the cells will belong to different Tracking Areas. For example, a Base Station which is shared between operators may have one set of cells belonging to a first Tracking Area for the first operator, and another set of cells belonging to a second Tracking Arca for the second operator * The 'Paging Priority' can be included to prioritise specific Paging messages at the Base Station. The priority can be configured with a value from I to 8, where 'I' represents the highest priority. The AMF deduces a priority level from the Allocation and Retention Priority (ARP) indicated by the SMF when requesting the AMF to page the VE. Specific services arc likely to have high ARP priorities, e.g. Mission Critical Services (MCS) and Multimedia P1riority Services (MPS)

5G NR in BULLETS * The 'UE Radio Capability for Paging' provides the Base Station with information regarding the operating bands supported by the UE. This can be used to reduce the number of cells which broadcast the RRC: Paging message, i.e. there is no need to broadcast a Paging message on a carrier which the UE docs not support. This parameter structure allows both 5G and 4G operating bands to be listed. The 4G operating bands are applicable when the 5G Core Network is connected to a next generation eNode B (ng-eNode B), i.e. a Base Station which supports the 4G air-interface * The'Assistance Data for Paging' can be used to provide a list ofrecommended cells. This list can include cells which the UE has previously visited, and it can also include cells which the UE has noot previously visited. [n the case of previously visited cells, the AMF specifics the time that the UE spent in each cell. Ifthe time is, greater than 4095 seconds then the AMF signals a value of 4095 seconds. The Base Station can use this information when selecting the cells to broadcast the RRC: Paging message. The AMF derives the set ofrecommended cells from information previously received from the Base Station. A Base Station can provide the AMF with information regarding recommended cells and RAN nodes for paging within the NGAP: VE Con/ex/ Release Complete message. The * AMF stores this information for any subsequent paging procedures The'Assistance Data for Paging' can also be used to provide the Base Station with information regarding the re-transmission of NGAP: Paging messages. The AMF can specify the current paging attempt count and the total number ofattempts which arc planned. The AMF can also specify whether or not it plans to change the scope ofthe geographic paging area on the next paging attempt. The Base Station can use this information to help define its own paging strategy. For example, ifthe AMF is approaching its final paging attempt then the Base Station can increase the priority of the paging procedure and potentially broadcast the RRC: Paging message across an increased number ofcells * The 'Paging Origin' flag is included when the paging procedure has been triggered for a POU Session which is associated with a non- 3GPP access technology. The UE uses the 3GPP access network to respond by sending a NAS: Service Request message. This message indicates whether or not the POU Session can be re-activated using the 3GPP access technology * Once the Base Station has received the NGAP: Paging message then it determines an appropriate Pagmg Frame and Paging Occasion for the RRC: Paging message to be scheduled across the air-interface. The Base Station uses Downlink Control Information (DCI) Format I_0 to allocate POSCH resources for the RRC: Paging message. The CRC bits are scrambled using the P-RNTI to indicate that the POSCH resource allocation is applicable to a paging procedure. The content ofDCl Format I_0 is presented in section 3.5.6 * Table 25 I presents the content ofan RRC: Paging message. A single message can include up to 32 paging records, and each paging record can address a single UE RRC: Paging Paging Rleocord List SEQUENCE (I to 32 inst~ancesf PagingRecord ue-ldentity CHOICE IIng-5G-S-TMSI ful/J-RNTI BIT STRING {40 bits) BIT STRING {48 bits} accessType non3GPP Table 2S1 - RRC: Paging message * The RRC: Pagmg message allows the UE to be addressed using either its 5G-S-TMSI or its 'full' 1-RNTI. The 1-RNTI is applicable to UE which are paged from RRC Inactive. The Base Station allocates an 1-RNTl when moving a UE from RRC Connected to RRC Inactive * The UE initiates the random access procedure after receiving an RIRC: Paging message. The RRC Setup Request message is sent as MSG3 using a cause value of'mt-Access'. A NAS: Service Request message is included within the RRC Setup Complete message. The Base Station forwards this NAS message to the AMF to complete the Paging procedure * For a UE in RRC Inactive, the serving Base Station maintains a record ofthe UE location in terms ofits allocated RAN Notification Area (RNA). The UE triggers an RRC Resume procedure with cause value 'ma-Update' ifit moves outside the allocated RNA. The UE does not update the network while moving within the allocated! RNA. In general, this means that paging messages must be broadcast by all Base Stations belonging to the allocated RNA * ln the case ofRRC Inactive, the UE specific NG-C connection towards the AMF and the UE specific NG-U connection towards the UPF arc maintained. This means that the AMF can continue to for.vard NAS messages towards the serving Base Station and the UPF can continue to forward downlink data towards the serving Base S1tation. The serving Base Station is responsible for paging the UE to allow reception ofthe downlink NAS message or downlink data * Figure 340 illustrates an example based upon the serving Base Stallion receiving downlink data from the UPF. The serving Base Station is reliant upon having an Xn connection towards each ofthe Base Stations within the RNA. The serving Base Station can then forward an XnAP: RAN Paging message to each Base Station. The XnAP: RAN Paging message is presented in Table 252 (alternatively, all cells within the RNA may belong to a single Base Station using th,e CU/DU Split architecture. In this case, it is not necessary to rely upon Xn connectivity) * The 'UE Identity Index Value' is set equal to '5G•S-TMSI mod 1024', i.e. a value from Oto I 023 which occupies IObits. This value allows the target Base Station to determine the Paging Frames and Paging Occasions without having to transfer the full 5G-S-TMSI across the Xn interface 417

5G NR in BULLETS RRC: Paging UPF i(I-RNT!--,-- i _.RRC: Paging RRC: Paging �\"- - i.(I-RN� (1-RNTI) XnAP: � RAN Paging -.._-_-(-1--.R_NTI) i RRC: Paging XnAP: RAN Paging / XnAP: ........, _�NTI) (1-RNTI) XnAP: RAN Paging RAN Paging (1-RNTI) ...... ---i----------RRC: Paging � (1-RNTI) --(1-RNTI) .,_/ Figure 340 - Distribution of Paging message for UE which is RRC Inactive UE Identity Index Value BIT STRING {JObits} XnAP: RAN Paging UE RAN Paging Identity Full 1-RNTI Paging DRX 32,64, 128,256 I BIT STRING {40bits} RAN Paging Area PLMN Identity I BIT STRING {24bits} CHOICE Cell List RAN Area Identity List SEQUENCE {I to 32 instances) SEQUENCE (I to 16 instances} NG-RAN Cell CHOICE RAN Area TAC BIT STRfNG {24bits} Identity Id RANAC 0 to 255 NR Cell Id E-UTRA Cell Id BIT STRING BIT STRING {36bits} {28bits} Paging Priority 1,2,3,4,5,6, 7,8 Assistance Data for RAN Paging RAN Paging Attempt Information Paging Attempt Count I to 16 Intended Number or Paging Attempts I to 16 Next Paging Area Scope Same, changed Table 252 - XnAP: RAN Paging message * The'UE RAN Paging Identity' is the full 1-RNTI which was allocated to the UE within the RRCRelease message when moving the UE to RRC Inactive. This identity is used to address the UE within the RRC: Paging message * The 'Paging DRX' specifics the DRX cycle used by the UE. This value allows the target Base Station to identify the appropriate Paging Frames and Paging Occasions * The 'RAN Paging Area' allows the target Base Station to identify the cells which are required to broadcast the RRC: Paging message. The set of cells can be specified explicitly using up to 32 Cell Global Identities (CG!). Alternatively, they can be specified using up to 16 RAN Area Identities. The use ofRAN Area Identities relies upon each cell being configured with both a Tracking Area Code (TAC) and RAN Area Code (RANAC) * The 'Paging Priority' can be included to prioritise specific Paging messages at the target Base Station. The priority can be configured with a value from I to 8, where'I' represents the highest priority. Ifthe paging procedure has been triggered by the reception ofa downlink NAS message from the AMF, then a \"RAN Paging Priority' may have been included within the NGAP: Downlink NAS Transport message * The•Assistance Data for RAN Paging' can be used to provide the target Base Station with information regarding the re-transmission of XnAP: RAN Paging messages. The serving Base Station can specify the current paging attempt count and the total number ofattempts which are planned. The serving Base Station can also specify whether or not it plans to change the scope ofthe geographic paging area on the next paging attempt * Figure 341 illustrates the paging procedure used to notify UE ofa change to the System Information or an incoming ETWS/CMAS message. This procedure is applicable to UE in RRC Connected, RRC Idle and RRC Inactive. In this case, the paging procedure does not use NGAP, XnAP nor RRC Paging messages. Instead, the paging procedure uses only the payload ofthe PDCCH. Downlink Control Information (DC!) Format l_0 can include a'Short Message' when the CRC bits are scrambled using the P-RNTI. This 'Short Message' can be used to indicate that System Information has been updated and needs to be re-acquired or there is an incoming ETWS/CMAS message 418