WO2020239445A1

WO2020239445A1 - Enhancing cell selection and reselection in new radio under rf exposure requirements

Info

Publication number: WO2020239445A1
Application number: PCT/EP2020/063322
Authority: WO
Inventors: Jorma Johannes Kaikkonen; Sami-Jukka Hakola; Timo Koskela; Jarkko Tuomo Koskela; Sari Kaarina Nielsen
Original assignee: Nokia Technologies Oy
Priority date: 2019-05-31
Filing date: 2020-05-13
Publication date: 2020-12-03

Abstract

Methods and apparatus, including computer program products, are provided for limiting RF exposure. In some example embodiment, there may be provided a method including estimating an amount of at least one restriction that needs to be applied in an uplink resource to comply with at least one emission requirement; and performing, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells. Related systems, methods, and articles of manufacture are also disclosed.

Description

ENHANCING CELL SELECTION AND RESELECTION IN NEW RADIO UNDER

RF EXPOSURE REQUIREMENTS

Field

[0001] The subject matter described herein relates to cellular and, more particularly, radio frequency (RF) exposure.

Background

[0002] In 5G (also referred to as New Radio, NR), a user equipment (UE) may have its uplink transmission controlled to comply with radio frequency (RF) exposure requirements, imposing limits on allowed effective isotropic radiated power (EIRP). Although these restrictions are designed to protect a user of the UE, these restrictions may degrade the performance of the UE. For example, a maximum permittable exposure (MPE) requirement may be imposed on the UE. This maximum permittable exposure requirement may, however, be highly directional due in part to the UE’s transmit beam -based operation. Examples of RF exposure requirements may be found in International Commission on Non-Ionizing Radiation Protection (ICNIRP) requirements or in FCC rules such as ICNIRP, ^"Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)," Health Phys., vol. 74, no. 4, pp. 494-522, Apr. 1998, and FCC, Code of Federal Regulations CFR Title 47, Part 1.1310, Radiofrequency Radiation Exposure Limits, Federal Communications Commission, Washington, DC, USA, Aug. 1997. For lower frequency bands below for example about 3 GHz for example, the RF exposure requirements may be set by a specific absorption rate (SAR). The SAR may determine the RF power absorbed by a certain mass (e.g., a mass of a living body in watts/kilogram). For frequencies above about 6 GHz for example, the limits may be set to define maximum exposure limits in terms of the maximum incident power density (watts/meter²) measured or averaged over a certain area (e.g., 20cm²). Summary

[0003] Methods and apparatus, including computer program products, are provided for limiting RF exposure.

[0004] In some example embodiment, there may be provided a method including estimating an amount of at least one restriction that needs to be applied in an uplink resource to comply with at least one emission requirement; and performing, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells.

[0005] In some variations, one or more of the features disclosed herein including the following features can optionally be included in any feasible combination. The at least one restriction may include an uplink duty cycle to the one or more candidate cells, an uplink transmit time over a time interval to the one or more candidate cells, a quantity of symbols transmitted over the time interval to the one or more candidate cells, an uplink transmit power to the one or more candidate cells, and/or a power reduction value for the uplink transmit power to the one or more candidate cells. The at least one emission requirement may represent a maximum permittable exposure requirement. The at least one mobility procedure may include a cell selection, a cell reselection, a ranking of cells for reselection, and/or a public land mobile network selection. An S criterion used for the cell selection may be determined based on the power reduction value and/or the uplink duty cycle. An R criterion used for the ranking may be determined based on the power reduction value and/or the uplink duty cycle.

[0006] The above-noted aspects and features may be implemented in systems, apparatus, methods, and/or articles depending on the desired configuration. The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims. Description of Drawings

[0007] In the drawings,

[0008] FIG. 1 depicts an example process for cell selection, in accordance with some example embodiments;

[0009] FIG. 2 depicts an example process for cell reselection, in accordance with some example embodiments;

[0010] FIG. 3 depicts an example of a network node, in accordance with some example embodiments; and

[0011] FIG. 4 depicts an example of an apparatus, in accordance with some example embodiments.

[0012] Like labels are used to refer to same or similar items in the drawings.

Detailed Description

[0013] To ensure compliance with applicable electromagnetic energy absorption requirements and address unwanted RF emissions, there are two techniques that may be used, such as the use of a P-MPR (maximum power reduction) value and a maxUplinkDutyCycle value (see, e.g., 3GPP TS 38.101-2, section 6.2.4). The P-MPR represents a reduction to the UE peak output power and, in particular, a peak maximum output power reduction value imposed on the UE’s uplink transmissions. The maxUplinkDutyCycle value represents a maximum duty cycle limit imposed on the UE’s uplink’s transmission. Table 1 below provides a summary of the P- MPR and the maxUplinkDutyCycle requirements (see, e.g., TS38.101-2 and TS 38.331). [0014] Table 1

1) P-MPR_{f c} is the allowed maximum output power reduction and maxUplinkDutyCycle as the maximum duty cycle to facilitate the compliance described below with P- MPR_{f c} < [a given threshold value in dB] The evaluation period for the

maxUplinkDutyCycle may be about 10ms, for example. The P-MPR_{f c} and the maxUplinkDutyCycle provide uplink transmission requirements which may

a) ensure compliance with applicable electromagnetic energy absorption

requirements and addressing unwanted emissions / self de-sense requirements in case of simultaneous transmissions on multiple RAT(s) for scenarios not in scope of 3GPP RAN specifications; and

b) ensure compliance with applicable electromagnetic energy absorption

requirements in case of proximity detection is used to address such requirements that require a lower maximum output power.

2) The UE may apply P-MPR_f,c for a carrier /of a serving cell c only for the above cases at a) and b). For conformance testing of the UE’s compliance with P-MPR_{f c,} it shall be 0 dB.

NOTE 1 : P-MPR_f,c was introduced in the P_CMAX,f,c equation such that the UE can report to the gNB the available maximum output transmit power. This information can be used by the gNB for scheduling decisions.

NOTE 2: P-MPR_{f c} and maxUplinkDutyCycle may impact the maximum uplink

performance for the selected UL transmission path.

[0015] As can be determined from Table 1, the use of both P-MPR and the uplink duty cycle to address RF exposure compliance may impact the maximum uplink performance for a selected uplink (UL) transmission path for a UE. The UE’s capability with respect to the maxUplinkDutyCycle may be signaled to the network, such as a radio access network served by a base station (e.g., gNB, eNB, etc.). For example, the UE may indicate to the network the UE’s preferred, maximum UL duty cycle. The value of the maxUplinkDutyCycle may be provided to the network in an information element (IE), such as the IE for RF -parameters, which may be a part of the UE capability information signaled to the network. In some example embodiments, the UE may apply the value of maxUplinkDutyCycle for transmission in one or more directions (e.g., in the uplink and/or downlink) that need to meet a defined emission requirements. By limiting the duty cycle of the uplink (such as the on time of the uplink or symbol transmit times over a given interval), the radiated power towards a user (e.g., a user’s body part, such as a user’s head) may be limited to comply with the RF emission requirements. The following depicts an example of the maxUplinkDutyCycle value which may be used by the UE to indicate to the network what the UE’s duty cycle is for one or more frequency bands:

maxUplinkDutyCycle-PC2-FR1 ENUMERATED (n60, n70, n80, n90, n100}

OPTIONAL, wherein the duty cycle in a given frequency band is enumerated, such as 60% for a given frequency band for example.

[0016] The cell selection and reselection procedure for 5G may specify the steps and metrics a UE may use to select a suitable cell for camping and the criteria for cell selections and/or re-selections (see, e.g., 3GPP TS 38.304, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; User Equipment (UE) procedures in Idle mode and RRC Inactive state (Release 15)). For the selection of candidate cells and cell re-selection candidates, the candidate cell selected may need to satisfy certain S criterion (based on the values of Srxlev (which is the cell selection receive level value in dB) and/or Squal (which is the cell selection quality value in dB) as defined in in section 5.2.3.2 of TS 38.304. The definition of Srxlev accounts for different parameters and offsets provided to the UE. These parameters include Pcompensation, that accounts the effect of maximum transmit power level that UE may use while transmitting an uplink in a cell. The definition of the measurement quantity of the cell may be specific to a given UE implementation. As described in TS 38.304, the cell selection criterion S is fulfilled when Srxlev > 0 AND Squal > 0, wherein

Srxlev Q_rxlevmeas— (Q_rxlevmin ⁺ Q_{rxlevminoffset} )— P_compensation ^_ Qoffset_temp Squal— Q_qualmeas— (Q_qualmin + Q_{qualminoffset}) - Qoffset_temp,

and the values are in accordance with Table 2.

[0017] Table 2

[0018] As can be seen by the equation above, the current S criterion used for cell selection does not take into account RF emission requirements, such as duty cycle (e.g., maxUplinkDutyCycle) or power limits (e.g., P-MPR).

[0019] In the case of cell reselection, the measurement quantity of a cell may be derived among the beams transmitted to the same cell based on one or multiple synchronization signal blocks (SSBs). The SSB may be defined based on (1) the highest beam measurement quantity (e.g., reference signal, received power (RSRP) based on a single SSB as given in 3 GPP TS 38.215); or (2) if absThreshSS-BlocksConsolidation and nrojSS-BlocksToAverage are configured (in a SIB2, for example), the average up to nrofSS-BlocksToAverage SSBs with a highest beam level measurement result that are above absThreshSS-BlocksConsolidation.

[0020] For re-selection, the candidate cells may also need to meet the defined S criterion. For intra-frequency cell selection, if the serving cell does not meet a provided minimum threshold for RSRP and/or reference signal receive quality, RSRQ (e.g., Srxlev > S_intraSearchP and S_qual > S_intraSearchQ), the UE may be required to perform infra-frequency measurements and, as a result, may consider different cell re-selection candidates. When intra-frequency (or equal priority inter- frequency) cell ranking is carried out, the cells are ranked based on averaged RSRP measurement values applying configured offsets. Specifically, the UE may perform ranking of all cells that fulfil the cell selection criterion S, and then the cells may be ranked according to an R criterion by deriving Qmeas,n and Qmeas,s and calculating the R values using averaged RSRP results. For example, the cell-ranking criterion Rs (see, e.g., TS 38.304) for serving cell and R_n for neighboring cells is defined by:

R_s Q_meas,s ⁺ Q_hyst - Qoffset_temp

=

R_n = Q_meas,n -Qoffset - Qoffset_temp,

wherein the values of Q_meas, Qoffset, and Qoffsettemp are in accordance with Table 3.

[0021] Table 3

[0022] As in the case with an S criterion, the current R criterion does not take into account RF emission requirements, such as duty cycle (e.g., maxUplinkDutyCycle) or power limits (e.g., P-MPR).does not take into account.

[0023] Based on the UE’s antenna or antenna array gain, the maximum allowed transmission power may be established in order to meet the noted exposure limit for a given distance. This distance may be determined by the aforementioned requirements/guidelines and the antenna/antenna array gain for a given UE implementation.

[0024] The RF emission requirements may be used to determine the allowed maximum transmission power to meet certain emission limits (e.g., maximum permissible exposure limits when a certain object is within certain distance to the UE or its antenna). To meet the required limits or guidelines, this allowed maximum transmission power may then be used to determine a power back off (e.g., P-MPR, MPR, and/or the like) from the actual maximum transmission power capability of the UE and/or the maximum allowed transmission power. Alternatively or additionally, the noted RF emission requirements may also account for temporal, time aspects related to the emission determined over a certain time period. For example, the time domain transmit restrictions (e.g., duty cycle limits including a transmission on time and/or a quantity of symbols transmitted over a period) may also be determined to comply with the requirements or guidelines.

[0025] The UE may include a plurality of antenna panels. And, the UE may operate using these antenna panels in the downlink and/or the uplink using beams that are narrower, when compared to wider beam width omnidirectional beams. In some embodiments, the S criterion may be extended to take into account the P-MPR to enable compliance with RF emission requirements. As such, the maximum permittable exposure (MPE) limit provided by the P-MPR may affect cell selection and cell re-selection. If the UE uses a transmission duty cycle or transmit power reduction (e.g. P-MPR) to account for the MPE limits however, this may result in the UE selecting a cell for which the UL transmission restrictions due to MPE (e.g. duty cycle or transmit power) which is significantly worse, when compared to another suitable cell. For example, different cells may be received and/or transmitted with different beams, and these different beams may have different conditions with respect to RF exposure limits. To illustrate further, a first beam may be transmitted towards a user’s head, while a second beam may not radiate towards the user’s head. In this example, the first beam may require a lower duty cycle or power reduction to comply with MPE, when compared to the second beam. This example shows that cell selection and/or reselection may pick a cell that is not the strongest cell due to the MPE requirements (e.g. duty cycle or transmit power). Another illustrative example is when transmission duty cycle or transmit power reduction (e.g. P-MPR) to account for the MPE are different for different frequency bands and when accounting for the MPE restrictions, the UE may select a cell that is not the strongest cell.

[0026] In some embodiments, cell selection may augmented to take into account the transmit duty cycle, such as the percentage of symbols the UE is able to transmit in a given cell over a given time period and/or the transmit on time in order to enable compliance with MPE limits. In some embodiments, cell selection may be augmented to take into account the transmit power limits (e.g., P-MPR) in order to enable compliance with MPR limits. To enhance the cell selection and cell re-selection for example, the S criterion may be augmented to take into account the UE’s ability to transmit in a given cell while complying with the RF emission limits, such as the maximum permittable exposure (MPE) limits provided by the P-MPR and/or duty cycle (e.g., max UplinkDutyCycle) .

[0027] For determining a suitable cell for cell selection, an S criterion may be extended to take into account the UE’s ability for uplink transmission in a candidate cell. For example, a maximum percentage of uplink symbols (which may be indicative of the duty cycle) that the UE would be able to transmit to a given cell within a given evaluation period may be taken into account. For example, an S criterion may take into account and thus evaluate candidate cells based on duty cycle to each candidate cell. Referring to the user head example, the first beam to a first candidate cell may not be selected due to its lower duty cycle, when compared to the higher duty cycle of the second beam to another candidate cell.

[0028] For example, among cells that meet the S criterion, the UE may consider cells to which it may be able to use a highest percentage of uplink symbols (e.g., a highest duty cycle). The highest percentage of uplink symbols may be determined based on the UE’s estimate of the duty cycle (e.g., percentage of uplink symbols transmitted over an interval). For example, the UE may estimate the percentage of uplink symbols for the UE’s uplink transmission to cells at a maximum power or within a certain range of the maximum power. And, this estimation may be performed among cells which meet the extended S criterion, and that are within a configured or specified threshold of a strongest cell. The threshold may be relative to the strongest cell, which may be determined for example as a maximum allowed difference in received downlink signal quality (such as between the cell and the strongest cell like RSRP). [0029] Alternatively or additionally, an offset may be applied to an S criterion metric(s). The offset may be determined for a given cell based on a maximum percentage of uplink symbols that the UE would be able to transmit at a maximum power. For example, the offset value may be determined based on the UE’s estimation regarding how large a percentage of the uplink symbols the UE is able to transmit for a given cell, when transmitting at a maximum uplink transmit power (or, at about a maximum such as within a threshold amount of that maximum). For example, if the estimated uplink duty cycle of a given cell falls below a threshold of 70% for example, an additional offset (e.g., Qoffset_cycle) may be applied to an S criterion as follows:

Srxlev = Qrxlevmeas - (Qrxlevmin + Qrxlevminoffset ) - Pcompensation - Qoffsettemp - Qoffset_cycle,

where Qoffset_cycle, is 3 (dB) for example if duty cycle is below 70%. These thresholds and corresponding offsets may be specified in a standard, pre-configured in the UE (e.g., via a SIM), an/or provided to the UE in system information in cell specific or frequency layer specific way.

[0030] Alternatively or additionally, for a cell or frequency layer level, a threshold may be determined for an acceptable percentage of uplink symbols that the UE needs to be able to exceed (e.g., applied percentage of UL symbols greater than a threshold) before the cell may be considered for selection. In some implementations where very different types of cells are being considered (e.g. indoor hotspots and wide area macro cells), the network may set these thresholds in a cell specific manner (or in a cell group specific manner). By contrast, in implementations where the cells of a given frequency layer are more homogenous (e.g., all of mostly indoor hotspots where UL may not necessarily restrict the coverage/capacity), the threshold value(s) may be determined to be common for most or all of the cells in a given frequency layer.

[0031] Alternatively or additionally, the ranking of cells for re-selection may take into account the percentage of the uplink symbols the UE is able to transmit to a given cell, when transmitting at the UE’s maximum uplink transmit power or within certain threshold range from the maximum power. To illustrate further, the ranking or ranking criterion, such as an R criterion, may be adjusted by an additional offset of the ranking criterion. The additional offset may be determined based on the estimated percentage of uplink symbols that UE may transmit for the cell, when transmitting at the maximum power or within certain range from the maximum power.

[0032] Alternatively or additionally, the ranking or ranking criterion, such as an R criterion, may be augmented so that a higher ranking is applied to the cell(s) that the UE is able to support with the high percentage of UL symbols when transmitting at its maximum power (or within a certain range from the maximum power) or able to use higher transmit power (e.g., requiring a smaller PMPR). This may be applied to all candidate cells or cells which ranking criterion is within determined range (of the highest-ranking criterion). When determining a ranking of a cell, the UE may (based on the estimated applicable percentage of UL symbols (or applicable transmit power or P-MPR) to meet MPE limits when that percentage (or transmit power or MPR) does not meet a threshold configured by network) apply an offset to the cell ranking criterion. Alternatively or additionally, after determining the ranking criterion for the cells based on DL criterion (e.g. RSRP) and configured offsets, the UE may determine the final ranking order among set of highest ranked cells based on highest estimated applicable percentage of UL symbols (or e.g. lowest MPR) of a given cell.

[0033] In case of multi -beam uplink transmission, the UE’s estimated percentage of uplink symbols (which the UE may support at a maximum uplink transmit power, within a certain range from the maximum power, or an applicable transmit power or P-MPR) may be used to adjust the cell ranking of candidate cells for selection or re-selection. For example, the UE may only apply beam(s) with the highest percentage of uplink symbols that the UE may support at the maximum power transmission (or highest applicable transmit power or smallest MPR), when deriving cell quality. Alternatively or additionally, the UE may determine the cell quality based on beam(s) for which the UE may support a percentage of uplink symbols that exceed a certain threshold (or which applied MPR to meet the MPE limits is below certain threshold). If configured, the percentage of uplink symbols (or MPR or applicable transmit power) may be based on the highest, averaged (or lowest percentage) of uplink symbols among up to nrofSS- BlocksToAverage SSBs with highest beam level measurement result that are above the absThreshSS-BlocksConsolidation. When the maximum percentage of uplink symbols (or MPR or applicable transmit power) the UE can support is applied to a beam, the UE may offset the beam quality based on maximum percentage of uplink symbols (or MPR or applicable transmit power) required for the particular beam(s). When multiple beams are averaged to get a cell quality, the noted offsetting of beam measurement value may be performed prior to deriving an average of the measurement values of beams. The offsetting of the beam value may be specified (e.g., -3dB if maximum percentage of UL symbols is 50%) in a standard or configurable by the network (e.g., the network may indicate when that in case of maximum percentage of uplink symbols of 50% offset beam value by x dB).

[0034] Alternatively or additionally, the UE may account for the required maximum duty cycle (e.g., percentage of uplink symbols and/or the like) and/or required P-MPR, when performing public land mobile network (PLMN) selection or priority based reselection. In the case of PLMN selection for example, when reporting the detected PLMN identities to the non- access stratum (NAS), the UE may adjust the measured RSRP based on the maximum percentage of uplink symbols that the UE may support at its maximum transmit power or the P-MPR (e.g., the UE’s transmit power reduction) that the UE may need to apply if transmitting without uplink duty cycle restrictions duty cycle. This may be based on thresholds where the adjustment of RSRP reported to the non-access stratum depends on provided thresholds. The thresholds may determine whether the reported RSRP needs to be adjusted (depending on the applied percentage of uplink symbol or the level of transmit power reduction) and/or how much the reported RSRP needs to be adjusted (depending on the applied percentage of uplink symbol or the level of transmit power reduction). The UE may be provided (e.g. on its SIM or in system information block) threshold information regarding the minimum level for the percentage of uplink symbols allowed and/or a maximum P-MPR allowed to be used for the given PLMN. In some embodiments, when reporting the detected PLMN identities to the non-access stratum (NAS), UE may provide the percentage of uplink symbols and/or required P-MPR to NAS.

[0035] In the case of priority based re-selection handling for example, the UE may adjust (e.g., reduce) the provided priority of 5G frequency layer or frequency layer of some other radio access technology if the maximum percentage of uplink symbols required for the frequency layer would be below a certain threshold. Correspondingly, if the P-MPR (or applicable transmit power to meet the MPE limits) of a certain frequency layer exceeds the certain threshold, the UE may adjust the priority.

[0036] In some embodiments, in addition to the frequency layer specific priorities, the UE may be provided with a minimum percentage of UL symbols (and/or maximum P-MPR) that the UE is allowed on the given frequency layer before the UE needs to down prioritize it. In some embodiments, the amount of down prioritization may depend on the required percentage of UL symbols (and/or P-MPR). For example, the UE may be configured by the system information to reduce the absolute priority of the concerned carrier frequency by, for example, one step from 5 to 4, if the maximum percentage of uplink symbols does not exceed a given threshold, such as 60%. This adjustment may be carrier frequency dependent or different for paired spectrum (FDD) and unpaired spectrum (TDD) carriers.

[0037] Moreover, the Srxlev in the cell selection criteria may be extended to take into account how much the P-MPR the UE would require for a given cell. The UE’s maximum permissible exposure related UE transmit power reduction P-MPR at the UE maximum transmit power may take into account the Srxlev evaluation of the cell selection S criterion by including an additional new term, such as the UE estimated P-MPR to Pcompensation as follows: Pcompensation = max (P_EMAXI -P_powerclass- P-MPR, 0) (dB).

[0038] Or alternatively directly in Srxlev determination as follows:

Srxlev^— Q_rxlevmeas— (Q_rxlevmin + Q_{rxlevminoffset} )— P_compensation— P-MPR - Qoffset_temp.

[0039] Moreover, the cell-ranking criterion Rs for serving cell and R_n for neighboring cells may be extended to take in to account how much P-MPR the UE would require for a given cell. The UE’s maximum permissible exposure related UE transmit power reduction P-MPR at the UE maximum transmit power may take into account the cell-ranking criterion(s) by including an additional new term, such as the UE estimated P-MPR as follows:

R_s = Q_meas,s ⁺ Q_hyst - Qoffset_temp-Q_{pmpr _s}

R_n = Q_meas,n -Qoffset - Qoffset_temp-Q_{pmpr_ n}

wherein the Qpmp_ s is the offset corresponding to the level of P-MPR required for the serving cell and Qpmpr n is the offset corresponding to the level of P-MPR required for a neighboring cell.

[0040] Alternatively or additionally, the cell-ranking criterion Rs for serving cell and R_n for neighboring cells may be extended to take in to account the how large a percentage of the uplink symbols (within certain time) the UE is able to transmit for a given cell, when transmitting at a maximum uplink transmit power (or, at about a maximum such as within a threshold amount of that maximum) for a given cell. The UE’s maximum permissible exposure related UE transmit duty cycle restriction may take into account the cell-ranking criterion(s) by including an additional new term, as follows:

R_s ⁼ Q_meas,s ⁺tQhyst - Qoffset_temp-Qcycle s

R_n ⁼ Q_meas,n -QoffsCt - Qoffset_temp-Q_{cycle_n}

where the Qcycle_s is the offset corresponding to the percentage of the uplink symbols supported for the serving cell and Qcycle_n is the offset corresponding to the percentage of the uplink symbols supported for a neighboring cell. The value for Qcycle may be for example determined to be OdB if the duty cycle exceeds 70% and 2dB if not. The threshold and/or offsets could be separately defined for serving and neighboring cell(s)

[0041] FIG. 1 depicts an example process for cell selection, in accordance with some example embodiments.

[0042] At 110, the UE may determine cell selection parameters including cell selection parameters to determine cells that meet the S criterion. For example, the UE may scans the RF channels (or selected RF channels) based on stored information to search for the strongest cell(s), and may determine the cell selection parameters from broadcasted system information. The cell selection parameters (which may be provided by the system information) may provide the extended cell selection parameters, including an additional compensation value to be applied if the maximum percentage of uplink symbols does not exceed a threshold, such as 70%. Alternatively or additionally, the system information may provide an indication regarding whether Pcompensation accounting the applied P-MPR would need to be used for determining the Srxlev. Alternatively or additionally, the system information may provide a range for the S criterion (from the strongest), so that UE can select among the cells (within the range) based on the largest amount (or percentage) of time or transmit with largest power.

[0043] At 120, the UE may perform cell measurements based on downlink received symbols(s), and may evaluate the required duty cycle for one or more cells. This evaluation may include an evaluation of whether the UE would be required to limit its uplink transmission time (or percentage, for example) for a given cell if the UE was transmitting to that cell at its maximum power or close to its maximum power (e.g. a certain amount of dB away from its maximum transmit power). This estimation may be determined based on predefined internal value and/or based on a UE proximity (e.g., sensor) measurement s) to determine a presence of an object in a short distance, an ultrasound distance measurements, and/or the like. For example, the predefined interval may be a time duration within which the UL duty cycle is determined (e.g., 10ms). This interval may set by specification or configured by network.

[0044] At 130, among the cells that meet the S criterion, the UE may consider cells to which it would be able to transmit with a largest amount (or percentage) of time or transmit in the uplink with a certain signaled percentage assuming that the UE would be using its maximum transmit power or transmit power that would be within a certain range from its maximum transmit power. Alternatively or additionally, if the UE is provided with information regarding how to adjust the S criterion based on the maximum percentage of uplink symbols or applied P-MPR, the UE may determine the adjusted S criterion.

[0045] At 140, the UE may select the cell for which it is able to transmit without uplink transmission time limitations at its maximum power (or within a threshold amount to the maximum power). Alternatively or additionally, the UE may select the cell which allows the UE to use the largest amount uplink transmission at its maximum power or close to its maximum power. Alternatively or additionally, if the UE is provided with information regarding how to adjust the S criterion based on the maximum percentage of uplink symbols or applied P-MPR, the UE may select the cell based on the adjusted S criterion.

[0046] FIG. 2 depicts an example process for cell ranking as part of cell reselection, in accordance with some example embodiments.

[0047] At 210, the UE may obtain the parameters related to cell ranking which may be performed as part of cell re-selection (e.g. Qoffset, Qoffsettmp, etc.), and may then determine an R criterion for each cell that meets the S criterion. The UE may perform a ranking of all cells that fulfil the cell selection criterion S, and the cells are ranked according to an R criterion noted above by deriving Qmeas,n and Qmeas,s and calculating the R values using averaged RSRP results. [0048] At 220, the UE may evaluate the required percentage of uplink symbols the UE may transmit in each cell. Based on the percentage of uplink symbols, the EE may apply a correction to the obtained R criterion. For example, the EE may reduce cell-ranking criterion of the cell by an offset (e.g., 3dB) if the required percentage of uplink symbols is lower than a certain threshold duty cycle or on time (e.g., a 50% threshold).

[0049] At 230, the EE may select the cell with the highest R criterion adjusted to take into account the duty cycle, such as the percentage of uplink signal transmitted over an interval and/or the like. In this way, the selected cell takes into account the duty cycle limits that may be needed to comply with RF emission requirements.

[0050] In some device implementations, a device, such as the UE, may determine the duty cycle dynamically, so that it accounts observed changes based on for example proximity sensors and/or antenna panel used for transmission. Alternatively or additionally, the UE may determine the duty cycle based on some preconfigured value(s). These values could be preconfigured for example by the UE manufacture as a part of the design and development. As noted, the uplink transmit duty cycle may be determined as the highest portion of UL symbols that the UE may use for uplink transmission within a certain time period while ensuring that it is compliant with applicable electromagnetic energy absorption requirements.

[0051] In some example implementations, the applicable UL duty cycle may be determined when that the UE would be using its maximum output power or an output power within a certain range from the maximum output power. The duty cycle or the transmit power may be considered to be from a given antenna, antenna panels, and/or beams.

[0052] In some example embodiments, the UE may determine an amount of output power reduction dynamically for example accounting the input from proximity sensor and/or used. Alternatively or additionally, the UE may determine the output power reduction based on some preconfigured value(s), defined by e.g. UE implementation. The amount of output power reduction may be based on the maximum output power that can be used for UL transmission within a certain time period while ensuring that it is compliant with applicable electromagnetic energy absorption requirements. In some example implementations, the amount of output power reduction may be determined while assuming that UE would be transmitting continuously on UL resources (e.g., a duty cycle of 100%) or on a certain portion of possible UL resources (e.g., a duty cycle of 50%) from a certain antenna, antenna panels, and/or beams.

[0053] FIG. 3 depicts a block diagram of a network node 300, in accordance with some example embodiments. The network node 300 may be configured to provide one or more network side functions, such as a base station (e.g., RAN), AMF, PCF, AF, and/or other network nodes.

[0054] The network node 300 may include a network interface 302, a processor 320, and a memory 304, in accordance with some example embodiments. The network interface 302 may include wired and/or wireless transceivers to enable access other nodes including base stations, the Internet, and/or other nodes. The memory 304 may comprise volatile and/or non- volatile memory including program code, which when executed by at least one processor 320 provides, among other things, the processes disclosed herein with respect to a base station or other network nodes.

[0055] FIG. 4 illustrates a block diagram of an apparatus 10, in accordance with some example embodiments. The apparatus 10 may represent a user equipment (UE), in accordance with some example embodiments.

[0056] The apparatus 10 may include at least one antenna 12 in communication with a transmitter 14 and a receiver 16. Alternatively transmit and receive antennas may be separate. The apparatus 10 may also include a processor 20 configured to provide signals to and receive signals from the transmitter and receiver, respectively, and to control the functioning of the apparatus. Processor 20 may be configured to control the functioning of the transmitter and receiver by effecting control signaling via electrical leads to the transmitter and receiver. Likewise, processor 20 may be configured to control other elements of apparatus 10 by effecting control signaling via electrical leads connecting processor 20 to the other elements, such as a display or a memory. The processor 20 may, for example, be embodied in a variety of ways including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processor(s) without an accompanying digital signal processor, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits (for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and/or the like), or some combination thereof. Accordingly, although illustrated in FIG. 4 as a single processor, in some example embodiments the processor 20 may comprise a plurality of processors or processing cores.

[0057] The apparatus 10 may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like. Signals sent and received by the processor 20 may include signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wireline or wireless networking techniques, comprising but not limited to Wi-Fi, wireless local access network (WLAN) techniques, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, 802.3, ADSL, DOCSIS, and/or the like. In addition, these signals may include speech data, user generated data, user requested data, and/or the like.

[0058] For example, the apparatus 10 and/or a cellular modem therein may be capable of operating in accordance with various first generation (1G) communication protocols, second generation (2G or 2.5G) communication protocols, third-generation (3G) communication protocols, fourth-generation (4G) communication protocols, fifth-generation (5G) communication protocols, Internet Protocol Multimedia Subsystem (IMS) communication protocols (for example, session initiation protocol (SIP) and/or the like. For example, the apparatus 10 may be capable of operating in accordance with 2G wireless communication protocols IS-136, Time Division Multiple Access TDMA, Global System for Mobile communications, GSM, IS-95, Code Division Multiple Access, CDMA, and/or the like. In addition, for example, the apparatus 10 may be capable of operating in accordance with 2.5G wireless communication protocols General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), and/or the like. Further, for example, the apparatus 10 may be capable of operating in accordance with 3G wireless communication protocols, such as Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), Wideband Code Division Multiple Access (WCDMA), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), and/or the like. The apparatus 10 may be additionally capable of operating in accordance with 3.9G wireless communication protocols, such as Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and/or the like. Additionally, for example, the apparatus 10 may be capable of operating in accordance with 4G wireless communication protocols, such as LTE Advanced, 5G, and/or the like as well as similar wireless communication protocols that may be subsequently developed.

[0059] It is understood that the processor 20 may include circuitry for implementing audio/video and logic functions of apparatus 10. For example, the processor 20 may comprise a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital- to-analog converter, and/or the like. Control and signal processing functions of the apparatus 10 may be allocated between these devices according to their respective capabilities. The processor 20 may additionally comprise an internal voice coder (VC) 20a, an internal data modem (DM) 20b, and/or the like. Further, the processor 20 may include functionality to operate one or more software programs, which may be stored in memory. In general, processor 20 and stored software instructions may be configured to cause apparatus 10 to perform actions. For example, processor 20 may be capable of operating a connectivity program, such as a web browser. The connectivity program may allow the apparatus 10 to transmit and receive web content, such as location-based content, according to a protocol, such as wireless application protocol, WAP, hypertext transfer protocol, HTTP, and/or the like.

[0060] Apparatus 10 may also comprise a user interface including, for example, an earphone or speaker 24, a ringer 22, a microphone 26, a display 28, a user input interface, and/or the like, which may be operationally coupled to the processor 20. The display 28 may, as noted above, include a touch sensitive display, where a user may touch and/or gesture to make selections, enter values, and/or the like. The processor 20 may also include user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as the speaker 24, the ringer 22, the microphone 26, the display 28, and/or the like. The processor 20 and/or user interface circuitry comprising the processor 20 may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, for example, software and/or firmware, stored on a memory accessible to the processor 20, for example, volatile memory 40, non-volatile memory 42, and/or the like. The apparatus 10 may include a battery for powering various circuits related to the mobile terminal, for example, a circuit to provide mechanical vibration as a detectable output. The user input interface may comprise devices allowing the apparatus 20 to receive data, such as a keypad 30 (which can be a virtual keyboard presented on display 28 or an externally coupled keyboard) and/or other input devices.

[0061] As shown in FIG. 4, apparatus 10 may also include one or more mechanisms for sharing and/or obtaining data. For example, the apparatus 10 may include a short-range radio frequency (RF) transceiver and/or interrogator 64, so data may be shared with and/or obtained from electronic devices in accordance with RF techniques. The apparatus 10 may include other short-range transceivers, such as an infrared (IR) transceiver 66, a Bluetooth™ (BT) transceiver 68 operating using Bluetooth™ wireless technology, a wireless universal serial bus (USB) transceiver 70, a Bluetooth™ Low Energy transceiver, a ZigBee transceiver, an ANT transceiver, a cellular device-to-device transceiver, a wireless local area link transceiver, and/or any other short-range radio technology. Apparatus 10 and, in particular, the short-range transceiver may be capable of transmitting data to and/or receiving data from electronic devices within the proximity of the apparatus, such as within 10 meters, for example. The apparatus 10 including the Wi-Fi or wireless local area networking modem may also be capable of transmitting and/or receiving data from electronic devices according to various wireless networking techniques, including 6LoWpan, Wi-Fi, Wi-Fi low power, WLAN techniques such as IEEE 802.11 techniques, IEEE 802.15 techniques, IEEE 802.16 techniques, and/or the like.

[0062] The apparatus 10 may comprise memory, such as a subscriber identity module (SIM) 38, a removable user identity module (R-UIM), an eUICC, an UICC, and/or the like, which may store information elements related to a mobile subscriber. In addition to the SIM, the apparatus 10 may include other removable and/or fixed memory. The apparatus 10 may include volatile memory 40 and/or non-volatile memory 42. For example, volatile memory 40 may include Random Access Memory (RAM) including dynamic and/or static RAM, on-chip or off- chip cache memory, and/or the like. Non-volatile memory 42, which may be embedded and/or removable, may include, for example, read-only memory, flash memory, magnetic storage devices, for example, hard disks, floppy disk drives, magnetic tape, optical disc drives and/or media, non-volatile random access memory (NVRAM), and/or the like. Like volatile memory 40, non-volatile memory 42 may include a cache area for temporary storage of data. At least part of the volatile and/or non-volatile memory may be embedded in processor 20. The memories may store one or more software programs, instructions, pieces of information, data, and/or the like which may be used by the apparatus for performing operations disclosed herein with respect to the UEs. [0063] The memories may comprise an identifier, such as an international mobile equipment identification (IMEI) code, capable of uniquely identifying apparatus 10. The memories may comprise an identifier, such as an international mobile equipment identification (IMEI) code, capable of uniquely identifying apparatus 10. In the example embodiment, the processor 20 may be configured using computer code stored at memory 40 and/or 42 to the provide operations disclosed herein with respect to the UE.

[0064] Some of the embodiments disclosed herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and/or hardware may reside on memory 40, the control apparatus 20, or electronic components, for example. In some example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a“computer-readable medium” may be any non- transitory media that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer or data processor circuitry, with examples depicted at FIG. 4, computer-readable medium may comprise a non-transitory computer-readable storage medium that may be any media that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

[0065] For example, the UE may estimate an amount of at least one restriction that needs to be applied in an uplink resource (e.g., resources on the transmitted uplink) to comply with at least one emission requirement. The UE may perform, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells. The at least one restriction may include an uplink duty cycle to the one or more candidate cells, an uplink transmit time over a time interval to the one or more candidate cells, a quantity of symbols transmitted over the time interval to the one or more candidate cells, an uplink transmit power to the one or more candidate cells, and/or a power reduction value for the uplink transmit power to the one or more candidate cells. The at least one emission requirement may represent a maximum permittable exposure requirement. The at least one mobility procedure may include a cell selection, a cell reselection, a ranking of cells for reselection, and/or a public land mobile network selection. An S criterion used for the cell selection may be determined based on the power reduction value and/or the uplink duty cycle. An R criterion used for the ranking may be determined based on the power reduction value and/or the uplink duty cycle. The S criterion and the R criterion may be in accordance with 3 GPP TS 38.304.

[0066] Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein may be cell selection and cell reselection procedures by enabling the UE to select a cell on which the transmission percentage of UL symbols at the UE’s maximum power is maximized and thus uplink performance is not be impacted as would with the existing methods.

[0067] The subject matter described herein may be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration. For example, the base stations and user equipment (or one or more components therein) and/or the processes described herein can be implemented using one or more of the following: a processor executing program code, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), an embedded processor, a field programmable gate array (FPGA), and/or combinations thereof. These various implementations may include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. These computer programs (also known as programs, software, software applications, applications, components, program code, or code) include machine instructions for a programmable processor, and may be implemented in a high-level procedural and/or object- oriented programming language, and/or in assembly/machine language. As used herein, the term “computer-readable medium” refers to any computer program product, machine-readable medium, computer-readable storage medium, apparatus and/or device (for example, magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions. Similarly, systems are also described herein that may include a processor and a memory coupled to the processor. The memory may include one or more programs that cause the processor to perform one or more of the operations described herein.

[0068] Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations may be provided in addition to those set forth herein. Moreover, the implementations described above may be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed above. Other embodiments may be within the scope of the following claims.

[0069] If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of some of the embodiments are set out in the independent claims, other aspects of some of the embodiments comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims. It is also noted herein that while the above describes example embodiments, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications that may be made without departing from the scope of some of the embodiments as defined in the appended claims. Other embodiments may be within the scope of the following claims. The term“based on” includes“based on at least.” The use of the phase“such as” means“such as for example” unless otherwise indicated.

Claims

1. An apparatus comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to at least:

estimate an amount of at least one restriction that needs to be applied in an uplink resource to comply with at least one emission requirement; and

perform, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells.

2. The apparatus of claim 1, wherein the at least one restriction comprises an uplink duty cycle to the one or more candidate cells, an uplink transmit time over a time interval to the one or more candidate cells, a quantity of symbols transmitted over the time interval to the one or more candidate cells, an uplink transmit power to the one or more candidate cells, and/or a power reduction value for the uplink transmit power to the one or more candidate cells.

3. The apparatus of any of claims 1-2, wherein the at least one emission

requirement represents a maximum permittable exposure requirement.

4. The apparatus of any of claims 1-3, wherein the at least one mobility procedure comprises a cell selection, a cell reselection, a ranking of cells for reselection, and/or a public land mobile network selection.

5. The apparatus of any of claims 1-4, wherein an S criterion used for the cell selection is determined based on the power reduction value and/or the uplink duty cycle.

6 The apparatus of any of claims 1-5, wherein an R criterion used for the ranking is determined based on the power reduction value and/or the uplink duty cycle.

7. The apparatus of any of claims 5-6, wherein the S criterion and the R criterion are in accordance with 3 GPP TS 38.304.

8. An method comprising:

estimating an amount of at least one restriction that needs to be applied in an uplink resource to comply with at least one emission requirement; and

performing, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells.

9. The method of claim 8, wherein the at least one restriction comprises an uplink duty cycle to the one or more candidate cells, an uplink transmit time over a time interval to the one or more candidate cells, a quantity of symbols transmitted over the time interval to the one or more candidate cells, an uplink transmit power to the one or more candidate cells, and/or a power reduction value for the uplink transmit power to the one or more candidate cells.

10. The method of any of claims 8-9, wherein the at least one emission requirement represents a maximum permittable exposure requirement.

11. The method of any of claims 8-10, wherein the at least one mobility procedure comprises a cell selection, a cell reselection, a ranking of cells for reselection, and/or a public land mobile network selection.

12. The method of any of claims 8-11, wherein an S criterion used for the cell selection is determined based on the power reduction value and/or the uplink duty cycle.

13. The method of any of claims 8-12, wherein an R criterion used for the ranking is determined based on the power reduction value and/or the uplink duty cycle.

14. The method of any of claims 12-13, wherein the S criterion and the R criterion are in accordance with 3GPP TS 38.304.

15. An apparatus comprising:

means for estimating an amount of at least one restriction that needs to be applied in an uplink resource to comply with at least one emission requirement; and

means for performing, based on the estimated amount of the at least one restriction, at least one mobility procedure to the one or more candidate cells.

16. The apparatus of claim 15 further comprising means for performing any of claims 9-14.

17. A non-transitory computer-readable storage medium including program code which when executed causes operations comprising: