TECHNICAL FIELD

The present application relates to the field of mobile communication and in particular to a network node and a method for performing sidelink (SL) transmission. More specifically, the present application relates to prioritized power control for Vehicle-to-Everything (V2X) SL in the context of 5G New Radio (NR) V2X.

BACKGROUND

5G NR V2X communication (starting from 3GPP Release 16) complements LTE V2X (from Rel. 14 and 15) and supports advanced V2X use cases such as vehicle platooning, extended sensors, advanced driving, and remote driving. It is further feasible to support unicast, group cast and broadcast operation in SL via PC5 interface, enables coexistence between SL and other cellular transmissions in a carrier, provides in-coverage, partial coverage, and out-of-coverage operation, as well as cross-RAT (Radio Access Technology) control.

In particular, NR V2X SL Power Control provides open- loop power control (OLPC) procedures that are supported for SL. When a transmitting SL user equipment (UE) is in-coverage, a Next Generation Node B (gNB) can enable OLPC for a unicast, groupcast or broadcast transmission based on the path loss between the transmitting UE and its serving gNB in order to mitigate interference to the gNB's UL reception. Additionally, at least for unicast, (pre-)configuration can enable also using the path loss between a transmitting and receiving UE.

In the prior art, SL power control mechanisms have considered avoiding interference to Uu transmissions: certain applications may require guarantees for SL transmissions (e.g., high priority Vehicle-to- Vehicle (V2V) applications), meaning successful SL packet reception is crucial. In case of a shared Uu/SL carrier, when a SL transmission has a higher priority compared to a Uu transmission, determining the transmit power for a particular SL transmission by compensating for Uu path loss and interference conditions may not ensure successful packet reception at the SL receiver as the path loss and interference conditions associated with UL/DL and SL can vary significantly. FIG. 20 shows example scenarios of high priority SL transmissions (e.g. over the PC5 interface) interfered by Uu transmissions on a shared Uu/SL carrier:

Example 1 (SL Mode 1): Uu transmissions in shared carrier are known to be low priority (e.g., MBB traffic), defined either statically (always) or dynamically (configuration/ signaling) .

Example 2 (SL Mode 2): Mode 2 transmission in partial coverage, UE detects lower priority Uu transmission.

In case of multiple simultaneous uncoordinated SL transmissions in a same RB in the vicinity of one another, inappropriate SL transmit power may result in high interference scenario thus reducing packet reception success rate.

LIG. 21 shows example scenarios of interference due to multiple uncoordinated SL transmissions on same resources:

Example 3: Two or more uncoordinated (e.g., Mode 1 & Mode 2 shared resource) SL transmissions of in a same RB.

Example 4: Two or more Mode 2 GL transmissions with overlapping TLRPs.

The 3GPP standard addresses the problem of SL transmit power control: V2V communications power control is supported by the 3 GPP standard LTE-A Releases 14 and 15, as well as the upcoming standard NR (New Radio) Release 16. Irrespective of the mode of the SL transmission, the provided solutions in Release 14 and 15, as well as upcoming standard NR Release 16, consider power values computed based on DL path loss compensation or DL and SL path loss compensations, and maximum allowed transmit power. Additionally, in NR Release 16, separately configuring parameters such as, Po and alpha values, for DL and SL of the existing power control equation are considered. In particular Po is the power a UE can transmit if the measured path loss is OdB. In particular, alpha is a path loss compensation factor. In particular, these parameters (Po and alpha) can be configured by higher layers based on resource configuration.

However, the prior art limits the number of power values that can be assigned to a SL transmitter to: maximum allowed transmit power or appropriately chosen path loss compensation based transmit power. Setting different values for certain parameters such as Po and alpha in the existing power control scheme or its modifications for path loss compensated transmit power values may not necessarily increase the range of transmit power values that a SL transmitter can be assigned with. The limited number of SL transmit power values may be insufficient to enable SL reachability due to unknown interference at the SL receiver. If a maximum allowed transmit power is chosen, it may not be required for the specific SL application or can result in increased interference.

That is, in the prior art there is the challenge to further improve determining of the SL transmit power.

SUMMARY

In view of the above-mentioned problems and disadvantages, the present invention aims to improve the conventional network nodes for performing SL transmission.

The embodiments of the invention in particular allow to determine the SL transmit power for unicast and groupcast transmissions to improve the probability of successful packet reception at the SL receiver(s) for high priority SL transmissions by considering at least one of: priority of SL transmissions relative to Uu or other SL transmissions; coverage scenarios (in-coverage, partial coverage and out-of-coverage);

- path loss (UL/DL or SL); and interference conditions at the intended SL receiver(s).

In other words, embodiments of the invention allow for joint consideration of SL transmission priority and receiver interference for SL transmit power control. This addresses the case of one SL transmission being prioritized over another SL transmission. This also provides transmit power control for SL in groupcast case, as well as in different coverage scenarios for SL transmissions.

Again in other words, existing power control mechanisms are enhanced by introducing new variables to provide a unified power control mechanism for SL transmissions taking into account multiple factors mentioned above to improve packet reception success rate at a SL receiver particularly in the case of high priority SL transmissions. The objective is achieved by the embodiments of the invention as described in the enclosed independent claims. Advantageous implementations of the embodiments of the invention are further defined in the dependent claims.

A first aspect of the present invention provides a network node for performing side link, SL, transmission, wherein the network node is configured to obtain a transmit power value for a SL transmission, the transmit power value being defined according to a comparison of a first priority indication of the SL transmission with a second priority indication. The second priority indication can be a priority of one or more concurrent transmissions or a default value (e.g., configured or preconfigured by the gNB).

This is beneficial, as it enables higher reception success for high priority SL transmissions. The present invention also allows for prioritizing SL transmissions over concurrent uplink transmissions in terms of transmit power, and allows for prioritizing SL transmissions over another SL transmission in terms of transmit power. The present invention ensures that the aspect of SL priority and interference at the SL receiver is included in computing the transmit power. Moreover, a solution for power control in case of relevant SL coverage scenarios is provided.

In particular, the network node may be a base station, or a user equipment.

In an implementation form of the first aspect, the first priority indication indicates a priority of an application or a transmission type associated with or of a type of the SL transmission and the second priority indication indicates a priority of an application or a transmission type associated with or of a type of the one or more concurrent transmissions.

In particular, the one or more concurrent transmissions include at least one SL transmission and/or at least one Uu transmission. In particular, the priority can be mapped to an application (e.g. emergency service) or to a transmission type (e.g., higher priority of unicast transmission, lower priority of broadcast transmission).

In particular, the application is a V2X application, e.g. for implementing co-operative awareness. The application may be included in several classes, such as road safety, traffic efficiency, etc. In particular, the transmit power value is defined according to a comparison of a first priority indication of the SL transmission with a second priority indication of one or more concurrent transmissions.

In other words, the first priority indication indicates a priority of an application associated with the SL transmission and/or the first priority indication indicates a priority of a type of the SL transmission. In other words, the second priority indication indicates a priority of an application associated with the one or more concurrent transmissions and/or the second priority indication indicates a priority of a type of the one or more concurrent transmissions.

The second priority can be explicitly indicated by an entity involved in concurrent transmission or can be set to a default value (e.g., by gNB). The default value for second priority indicates to the transmitter of the SL transmission with first priority the assumed priority of any concurrent transmission (e.g., in case the second priority indication is not received for initial transmission, or in case where the SL transmission with the first priority has stringent latency requirement and waiting to receive the second priority indication would violate that latency requirement).

In particular, the transmit power value is further defined according to a comparison of the priority of the SL transmission to a priority of a Uu transmission. In particular, the Uu transmission is transmitted or received by a base station. In this case, the priority of the Uu transmission is obtained in the BS.

In a further implementation form of the first aspect, the network node is further configured to compare the priority of the SL transmission to a priority of a Uu transmission or of at least one other SL transmission, to determine the transmit power value.

In particular, the at least one other SL transmission is transmitted or received by at least one other UE.

In particular, the at least one other UE is in coverage of a BS (which includes the network node). In this case, the priority of the at least one other SL transmission can be signaled by the UE to the BS directly or to another UE. In particular, the at least one other UE is not in coverage of the BS. In this case, the priority of the at least one other SL transmission can be signaled by the UE to the BS indirectly (i.e. it is forwarded by other entities), or can be preconfigured in the BS by the UE (i.e. at an earlier time when the UE is in coverage of the BS).

In a further implementation form of the first aspect, the transmit power value is further based on an interference value obtained from a receiver of the SL transmission, if the first priority indication is higher than the second priority indication.

This is beneficial as the transmit power value can be determined both based on a priority and on an interference value of a transmission. That is, more values can be considered when determining the transmit power value.

In particular, the interference value relates to interference due to one or more UE transmissions, one or more SL transmissions, or a combination of UE and SL transmissions.

In particular, the interference value relates to an interference of the SL transmission with a Uu transmission, experienced at the receiver of the SL transmission.

In particular, the Uu transmission is transmitted or received by the base station. In particular, the interference value indicates how signal reception at the receiver of the SL transmission is interfered by the Uu transmission.

In particular, the interference value relates to an interference of the SL transmission with at least one other SL transmission, experienced at the receiver of the SL transmission.

In particular, the at least one other SL transmission is transmitted or received by at least one other UE (e.g. the at least one other UE is in coverage of the BS or out of coverage of the BS). In particular, the interference value indicates how signal reception at the receiver of the SL transmission is interfered by the at least one other SL transmission.

In a further implementation form of the first aspect, the transmit power value is further based on a SL path loss value obtained from a receiver of the SL transmission. In a further implementation form of the first aspect, the path loss value relates to Uu path loss of a Uu transmission, experienced at the receiver of the SL transmission.

That is, the receiver of the SL transmission also receives Uu transmission from the BS, based on which the path loss is detected.

In a further implementation form of the first aspect, the path loss value further relates to path loss of the SL transmission and/or at least one other SL transmission experienced at the receiver of the SL transmission.

That is, the receiver of the SL transmission determines the pass loss based on the SL transmission that is received from the UE. Additionally or alternatively, the receiver of the SL transmission (which is intended to receive the SL transmission of the UE) also receives SL transmission from at least one other UE. Based on the SL transmission from the at least one other UE, the pass loss can be determined.

Using the above path loss value is beneficial as the transmit power value can be determined both based on a priority and on the path loss value. That is, more values can be considered when determining the transmit power value.

In a further implementation form of the first aspect, the network node is further configured to compare the SL path loss value with the Uu path loss value, wherein the transmit power value is further based on the SL path loss value exclusively, if the SL path loss value is larger than the Uu path loss value.

In a further implementation form of the first aspect, the transmit power value is further based on the SL path loss value exclusively, if the first priority indication is higher than the second priority indication.

In particular, in case that the first priority indication is set to a value higher or equal than the priorities of any concurrent transmissions or than the (pre-)configured default value of the second priority, the comparison is done without the need of receiving the second priority indication and the transmit power is calculated based only on the path loss of the SL transmission associated with the first priority indication.

In a further implementation form of the first aspect, the network node is configured to receive the second priority indication from an entity involved in a concurrent transmission, or the second priority indication is pre-set to a default value in the network node.

In a further implementation form of the first aspect, the transmit power value is set to a pre defined value, if the first priority indication is associated to a predefined set of applications or transmission types.

Conversely, in case when the first priority indication is set to a value lower than the priority of one or more concurrent transmissions or than the (pre-)configured default value of the second priority, the SL transmission associated with the first priority indication is terminated.

In a further implementation form of the first aspect, the SL transmission is a unicast transmission and/or a group-cast transmission.

In a further implementation form of the first aspect, the network node is a Base Station and is further configured to transmit the obtained transmit power value to a User Equipment, UE, in coverage of the Base Station.

In a further implementation form of the first aspect, the UE is in coverage of the base station, the base station is further configured to update an SL transmit power in the UE based on the transmit power value.

In a further implementation form of the first aspect, if the UE is out of coverage of the base station, the base station is further configured to preconfigure an SL transmit power in the UE based on the transmit power configuration.

In a further implementation form of the first aspect, the network node is further configured to preconfigure constraints in the UE, based on which the preconfigured SL transmit power is activated. In a further implementation form of the first aspect, the network node is a User Equipment, UE, and is further configured to perform SL transmission using the obtained transmit power value.

This is beneficial because, if the network node is implemented at the UE side, the UE itself may determine its own transmit power.

A second aspect of the present invention provides a method for performing side link, SL, transmission, wherein the method comprises the steps of obtaining, by a network node, a transmit power value for a SL transmission, the transmit power value being defined according to a comparison of a first priority indication of the SL transmission with a second priority indication of one or more concurrent transmissions.

In an implementation form of the second aspect, the first priority indication indicates a priority of an application associated with or of a type of the SL transmission and the second priority indication indicates a priority of an application associated with or of a type of the one or more concurrent transmissions.

In a further implementation form of the second aspect, the method further includes comparing, by the network node, the priority of the SL transmission to a priority of a Uu transmission or of at least one other SL transmission, to determine the transmit power value.

In a further implementation form of the second aspect, the transmit power value is further based on an interference value obtained from a receiver of the SL transmission, if the first priority indication is higher than the second priority indication.

In a further implementation form of the second aspect, the transmit power value is further based on a SL path loss value obtained from a receiver of the SL transmission.

In a further implementation form of the second aspect, the path loss value relates to Uu path loss of a Uu transmission, experienced at the receiver of the SL transmission.

In a further implementation form of the second aspect, the path loss value further relates to path loss of the SL transmission and/or at least one other SL transmission experienced at the receiver of the SL transmission. In a further implementation form of the second aspect, the method further includes comparing, by the network node, the SL path loss value with the Uu path loss value, wherein the transmit power value is further based on the SL path loss value exclusively, if the SL path loss value is larger than the Uu path loss value.

In a further implementation form of the second aspect, the transmit power value is further based on the SL path loss value exclusively, if the first priority indication is higher than the second priority indication.

In a further implementation form of the second aspect, the method further includes the step of receiving, by the network node, the second priority indication from an entity involved in a concurrent transmission, or the second priority indication is pre-set to a default value in the network node.

In a further implementation form of the second aspect, the transmit power value is set to a pre defined value, if the first priority indication is associated to a predefined set of applications or transmission types.

In a further implementation form of the second aspect, the SL transmission is a unicast transmission and/or a group-cast transmission.

In a further implementation form of the second aspect, the network node is a Base Station and the method further includes the step of transmitting, by the network node, the obtained transmit power value to a User Equipment, UE, in coverage of the Base Station.

In a further implementation form of the second aspect, the UE is in coverage of the base station, and the method further includes the step of updating, by the base station, an SL transmit power in the UE based on the transmit power value.

In a further implementation form of the second aspect, if the UE is out of coverage of the base station, the method further includes preconfiguring, by the base station, an SL transmit power in the UE based on the transmit power configuration. In a further implementation form of the second aspect, the method further includes preconfiguring, by the base station, constraints in the UE, based on which the preconfigured SL transmit power is activated.

In a further implementation form of the second aspect, the network node is a User Equipment, UE, and the method further includes the step of performing, by the UE, SL transmission using the obtained transmit power value.

The second aspect and its implementation forms include the same advantages as the first aspect and its respective implementation forms.

A third aspect of the present invention provides a computer program which, when executed by a processor, causes the method of the second aspect or any of its implementation forms to be performed.

A further aspect of the invention also relates to a computer program product comprising a computer readable medium and said mentioned computer program, wherein said computer program is included in the computer readable medium, and the computer medium comprises of one or more from the group: ROM (Read-Only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically EPROM) and hard disk drive.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. BRIEF DESCRIPTION OF DRAWINGS

The above-described aspects and implementation forms of the present invention will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 shows a schematic view of a network device according to an embodiment of the present invention.

FIG. 2 shows a schematic view of an operating scenario according to the present invention.

FIG. 3 shows a schematic view of an operating scenario according to the present invention.

FIG. 4 shows a schematic view of an operating scenario according to the present invention.

FIG. 5 shows a schematic view of an operating scenario according to the present invention.

FIG. 6 shows a schematic view of an operating scenario according to the present invention.

FIG. 7 shows a schematic view of an operating scenario according to the present invention.

FIG. 8 shows a schematic view of an operating scenario according to the present invention.

FIG. 9 shows a schematic view of an operating scenario according to the present invention.

FIG. 10 shows a schematic view of an operating scenario according to the present invention.

FIG. 11 shows unicast SF power control mechanisms according to the present invention. FIG. 12 shows group cast SF power control mechanisms according to the present invention. FIG. 13 shows unicast SF power control mechanisms according to the present invention. FIG. 14 shows group cast SF power control mechanisms according to the present invention. FIG. 15 shows a schematic view of a signaling scenario according to the present invention.

FIG. 16 shows a schematic view of a signaling scenario according to the present invention.

FIG. 17 shows a schematic view of a signaling scenario according to the present invention.

FIG. 18 shows a power control mechanism according to the present invention.

FIG. 19 shows a schematic view of a method according to an embodiment of the present invention.

FIG. 20 shows a schematic view of an operating scenario according to the prior art.

FIG. 21 shows a schematic view of operating scenario according to the prior art.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a schematic view of a network node 100 according to an embodiment of the present invention. The network node 100 is for performing SL transmission and is configured to obtain a transmit power value 101 for a SL transmission, the transmit power value 101 being defined according to a comparison of a first priority indication 102 of the SL transmission with a second priority indication 103 of one or more concurrent transmissions.

The network node 100 can be a base station BS or can be a user equipment UE, in particular a SL UE.

The first priority indication 102 optionally indicates a priority of an application associated with or of a type of the SL transmission. The second priority indication 103 optionally indicates a priority of an application associated with or of a type of the one or more concurrent transmissions. The network node 100 further optionally can compare the priority of the SL transmission to a priority of a Uu transmission or of at least one other SL transmission, to determine the transmit power value. In the following discussion several scenarios that can occur in a network when there are high priority SL transmissions are going to be discussed in view of possible solutions to improve reception success for each scenario. The following SL transmission scenarios are considered: SL transmissions prioritized over Uu transmissions for: o NR SL Mode 1 (BS-scheduled SL) transmissions (Scenario 1), or o NR SL Mode 2 (autonomously scheduled SL) transmissions (Scenario 2); Multiple SL transmissions with different priorities (Scenario 3).

The different scenarios that are going to be discussed below in view of FIG. 2 to FIG. 10 can be mapped to the tables in FIG. 11, FIG. 12, FIG. 13 and FIG. 14 to appropriately determine the TX power based on the scenario.

FIG. 2 illustrates Scenario la, where high priority SL transmissions are not interfered by Uu transmissions. The SL UE(s) (transmitter and receiver) are under BS coverage. A solution is to adapt transmit power of the TX UE to reach the receiver by overcoming SL path loss. The SL transmit power can be updated either by the BS or the SL transmitter (the UE).

LIG. 3 illustrates Scenario lb, where Uu transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver) are under BS coverage. A solution is to adapt SL Tx power to reach the receiver by overcoming interference at the Rx UE and SL path loss. The SL transmit power can be updated either by the BS or by the SL transmitter.

LIG. 4 illustrates scenario lc, where Uu transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver) are under partial BS coverage, that is, the SL transmitter is in-coverage, the SL receiver is out-of-coverage. A solution is to adapt the SL Tx power to reach the receiver by overcoming interference at Rx and SL path loss. SL transmit power can be updated either by the BS or the SL transmitter.

LIG. 5 illustrates scenario 2a, where high priority SL transmissions are not interfered by Uu transmissions. The SL UE(s) (transmitter and receiver) are under BS coverage. A solution is to adapt transmit power to reach the receiver by overcoming SL path loss. SL transmit power can be updated either by the BS or SL transmitter. FIG. 6 illustrates scenario 2b, where Uu transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver) are under BS coverage. A solution is to adapt SL Tx power to reach the receiver by overcoming interference at the Rx UT, and SL path loss. SL transmit power can be updated either by the BS or the SL transmitter.

FIG. 7 illustrates scenario 2c, where Uu transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver) are under partial or out of BS coverage. A solution is to adapt SL Tx power to reach the receiver by overcoming interference at the Rx UE and SL path loss. The SL transmit power can be updated either by the BS or the SL transmitter.

LIG. 8 illustrates scenario 3a, where high priority SL transmission is not interfered by other SL transmissions. The SL UE(s) (transmitter and receiver pairs) are under BS coverage. A solution is to adapt SL Tx power to reach the receiver by overcoming mainly SL path loss. The SL transmit power can be updated either by the BS or the SL transmitter.

LIG. 9 illustrates scenario 3b, where simultaneous SL transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver pairs) are under BS coverage. A solution is to a adapt SL Tx power to reach the receiver by overcoming mainly interference and SL path loss. The SL transmit power can be updated either by the BS or SL transmitter.

LIG. 10 illustrates scenario 3c, where simultaneous SL transmissions interfere with high priority SL transmissions. The SL UE(s) (transmitter and receiver pairs) are under partial or out of BS coverage. A solution is to adapt SL Tx power to reach the receiver by overcoming mainly interference and SL path loss. The SL transmit power can be updated either by the BS or SL transmitter.

As it is e.g. outlined in LIG. 2 to LIG. 10 above, the transmit power value 101 can be based on an interference value obtained from a receiver of the SL transmission, if e.g. the first priority indication 102 is higher than the second priority indication 103. The transmit power value 101 can further be based on a SL path loss value obtained from a receiver of the SL transmission (that is, one of the above receiving SL UEs). The path loss value also can relate to Uu path loss of a Uu transmission, experienced at the receiver of the SL transmission (that is, one of the above receiving SL UEs). The path loss value further can relate to path loss of the SL transmission and/or at least one other SL transmission experienced at the receiver of the SL transmission. The SL path loss value can be compared with the Uu path loss value, wherein the transmit power value 101 is further based on the SL path loss value if the SL path loss value is larger than the Uu path loss value and if the first priority indication 102 is higher than the second priority indication 103. The transmit power value 101 can be set to a pre-defmed value, if the first priority indication 102 is associated to a predefined set of applications or transmission types.

The enhancements of the present invention to enable priority based SL power control are now going to be described in view of FIG. 11 to FIG. 14 in more detail. The present invention in particular modifies the existing LTE SL power control mechanism for Mode 1 and Mode 2 described in 3GPP TS 36.213.

The proposed modifications are the following: Two variables (Bi and EL), which in the simplest case can take binary values, are introduced, whose purpose is the following:

By considering an equation with Bi and B2, SL transmit power for high priority SL transmissions can either be set to a certain pre-determined maximum value (Pma PCS IC / P max PC 5 oc ) or to a value depending on the path loss and interference at the receiver given by the function f((Popcs + 10 log (M) + apes PLpcs), Pmax PCS IC) which is lower bounded by: (Popes + 10 log (M) + apes PLpcs) and upper bounded by: Pmax PCS IC. Parameters Popes and apes are either pre-configured or can be determined based on interference information available at the entity configuring the transmit power (SL Tx or gNB).

In particular, Pmax PCS IC is the maximum SL transmit power for a SL UE transmitter in-coverage of a base station. In particular, Pma PCS oc is the maximum SL transmit power for a SL UE transmitter out-of-coverage of a base station. In particular, Popes is the power the UE can transmit on the SL if the measured path loss from the respective SL receiver is OdB. In particular, M is the number of assigned resource blocks. In particular, apes is a SL path loss compensation factor. In particular, PLpcs is path loss measured at the SL receiver.

The function f((Popcs + 10 log (M) + apes PLpcs), Pmax PCS IC) is any function that determines the SL transmission that improves the packet reception success at the SL receiver for high priority SL transmissions, considering the link quality between the receiver and the transmitter and the interference at the receiver.

In particular, the function f (PLpcs j , ... PLpcs N) is any function that determines a single representative path loss value for a group (e.g. min(), max(), or mean()) of multiple path loss values.

Furthermore, the modified equation allows further differentiation within high priority SL transmission based on:

Application type (e.g., to enable transmission at max power for emergency applications). For critical applications such as emergency, compensating for, or even considering interference at other receivers, is not a concern, thus maximum power is used.

Interference-based power setting, which might not be as critical as emergency, but has higher priority compared to Uu transmissions. Compared to case 1), some SL applications that are not as critical as emergency could benefit by compensating appropriately for interference at the receiver, as it can minimize interference and improve the probability of successful reception.

The proposed modifications further introduce additional variables for max power of SL transmission in and out of coverage (Pmax PCS ic , Pmax PCS oc ). This allows for limiting interference to Uu in coverage (in case of uncoordinated transmissions), and can be provided through configuration (e.g., by BS or via pre-configuration).

The above power control mechanism is in particular applied to the previously described scenarios. Specifically, the modifications are presented in FIG. 11 for SL/UL power control for Unicast (both in-coverage and out of coverage), FIG. 12 for SL/UL power control for Group cast (both in-coverage and out of coverage), FIG. 13 for SL/SL power control for Unicast (both in-coverage and out of coverage), and FIG. 14 for SL/SL power control for Group cast (both in-coverage and out of coverage). In all of the scenarios the choice of the variables B1 and B2 will decide whether the SL transmission is prioritized over the other transmissions (either the UL or another SL transmission); in case the SL transmission is prioritized, it will effectively ignore the impact it has on the interference of other transmissions. The values that the variables can hold are based on different factors that are described in the table associated with each of said four figures. Value ‘ 1 ’ indicates the part of the equation that is computed to determine the transmit power.

In particular, the equations of FIG. 13 can be interpreted as described in the following:

The Bi part of the equation corresponds to the SL transmission for which the transmit power needs to be determined. The B2part corresponds to another SL transmission in the vicinity of Bi SL transmission. If Bi is prioritized over B2, Tx power is is determined straightforward from the above equation. If B2 is prioritized over Bi (UC), Tx power is determined by a function that considers path loss associated with Bi part (Popes + 10 log (M) + apes PLpcs 1), interference at Rx for Bi part, and upper bounded by Pmax PCS ic2 (which is the max SL transmit power given SL transmission associated with B2 is prioritized).

Bi and B2 hold values provided in the table in Fig. 14. The above is in particular relevant for in- and out-of-coverage scenarios.

Signaling procedures for the above described scenarios 1, 2 and 3 (including sub-scenarios) are now going to be described in view of FIG. 15, FIG. 16 and FIG. 17.

Priority information is signaled as described in the following: As discussed in the above scenarios, the SL transmitter UE(s) can be in-coverage of the BS (Scenarios: la, lb, 2a, 2b, 3a, 3b). BS or SL transmitter UE can determine the transmit power parameters. Based on the entity determining the SL transmit power, the receiver interference information (e.g. SINR) can be shared with the entity.

The SL transmitter UE(s) can also be out-of-coverage of the BS (Scenarios: lc, 2c, 3c): The SL transmitter UE can determine the transmit power parameters. Transmit power parameters can be either pre-configured or informed to the UE when in-coverage. The receiver interference information (e.g. SINR) can be shared with the SL transmitter to determine the transmit power.

Signaling for scenario 1 is described in FIG. 15, signaling for scenario 2 is described in FIG. 16, and signaling for scenario 1 is described in FIG. 17. According to another embodiment of the present invention, the Rel. 14 power control equation can be extended to include the SL path loss (which is in line with statements above) as it is shown in FIG. 18.

Modifying the parameters of the equation of FIG. 18 (alpha l, alpha_2,P_l,P_2,etc.) allows for a "soft" switching of the priorities between Uu and SL path loss, i.e. the parameters can be chosen such that only SL path loss is considered. However, compensating for SL path loss only may not always ensure successful reception over the SL, mainly due to interference at the receiver. The present invention provides a solution to combat jointly both path loss and interference in case of SL prioritized over UL. In relation to the equation of FIG. 18, this means that in extreme cases where there is high priority application on SL and interference is high, disregarding the PL for both SL and UL and using PMax directly.

Specifically, before adapting the SL transmit power at a particular UE and given a specific SL mode (1 or 2) and scenario (in or partial coverage), if the SL is prioritized (e.g., due to high priority application), the purpose of the equation and the added variables are: to appropriately determine the SL transmit power based on multiple criteria such as those mentioned above; if SL is prioritized, determine the transmit power based on both the SL path loss and any existing interference to improve reception success e.g., referring to the equation above. In case of low interference and prioritized SL, B2 will be 1 and f((P0_PC5...) will be used. In case of high interference and prioritized SL, B2 will be 1 and P_max_PC5_IC will be used; and in addition to determining priority between Uu and PC5, the present invention also enables prioritizing a certain SL unicast/group cast transmission with respect to other SL unicast/group cast transmissions.

Comparing the equations shown in FIGs. 11 to 14 with the equation of FIG. 18, although alpha and P parameters (including Po) can be adapted to appropriately choose the power to compensate for path loss, the equation of FIG. 18 cannot account for interference at the receiver to adapt the SL transmit power, cannot address the case of one SL transmission prioritized over another SL transmission, and cannot (without further modification) address prioritization of SL in group cast case. FIG. 19 shows a schematic view of a method 1900 according to an embodiment of the present invention. The method 1900 is for performing SL transmission and comprises the step of obtaining 1901, by a network node 100, a transmit power value 101 for a SL transmission, the transmit power value 101 being defined according to a comparison of a first priority indication 102 of the SL transmission with a second priority indication 103 of one or more concurrent transmissions.

The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.