WO2020126114A1

WO2020126114A1 - Beam-selective transmission power control scheme

Info

Publication number: WO2020126114A1
Application number: PCT/EP2019/060792
Authority: WO
Inventors: Richard Stirling-Gallacher; Mario Castaneda; Zhongfeng Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-12-21
Filing date: 2019-04-26
Publication date: 2020-06-25
Also published as: EP3895335A1; CN113228530A; WO2020126042A1; CN113228530B

Abstract

The present invention relates to transmission power control at a wireless communication device (UE). In particular, the invention provides a UE for performing beam-selective transmission power control, and a device, for example a network device, for supporting beam-selective transmission power control. The UE is configured to receive a first parameter of a downlink beam-formed resource from the device to the UE and a second parameter of a sidelink beam- formed resource from a second UE to the UE. Further, it is configured to measure a first path loss based on the first parameter and a second path loss based on the second parameter, and to determine, based on the first and second path losses and according to a preconfigured determination scheme, a transmission power for a sidelink beam- formed resource to the second UE. The device is accordingly configured to transmit a first parameter of a downlink beam-formed resource from the device to the UE and a second parameter of a sidelink beam- formed resource from a second UE to the UE.

Description

BEAM-SELECTIVE TRANSMISSION POWER CONTROL SCHEME

TECHNICAL FIELD

The present invention relates to transmission power control performed at a wireless communication device or user equipment (UE). In particular, the invention provides a UE for performing beam-selective transmission power control, and provides a device, for example, a network device like a Transmit Receive Point (TRP), for configuring the beam- selective transmission power control at the UE. The invention also proposes corresponding transmission power control methods.

BACKGROUND Transmission power control is needed, for example, for 5G NR sidelinks (i.e. UE to UE links). Currently, however, no power control scheme exists, and conventional UE power control schemes (e.g. 5G NR Uplink and LTE sidelink) are not suitable.

Specifically, a power control scheme is needed, which optimizes sidelink performance for a wanted direction, and at the same time minimizes interference to co-channel and /or adjacent channel users (e.g. Uu uplink or other adjacent channel sidelinks). The conventional power control schemes are not suitable for this in their present form.

The conventional 5G NR sidelink power control scheme may be open- loop based, which means that the power control is just based on open-loop measurements made at the UE. Alternatively, the 5G NR sidelink power control can be a closed- loop based power control, which means that it uses a combination of open-loop measurements made at the UE and closed control signals from e.g. the serving TRP/gNB or another communication entity (e.g. a UE).

Conventional UE power control schemes include:

• LTE V2x / D2D sidelink power control

• LTE uplink power control

• 5 G NR UE uplink power control Due to different reasons, none of the above conventional schemes are suitable for 5G NR sidelink transmission power control. A quick summary of the conventional schemes, and why they are not suitable, is given below.

The LTE V2x / D2D sidelink power control (Release 12, 13 and 14 of LTE V2x) scheme is an open-loop scheme, which was originally designed to minimize the sidelink transmission power, such that it does not cause interference to the uplink user allocated in the adjacent band.

The UE makes downlink measurements of the received signal from the base station, and calculates the downlink pathloss (PL). In a very general way, the following equation shows how the transmission power (P) of the UE is set according to this scheme:

P = min {P_MAX, 10 log ₁₀ (M) + P₀ + a - PL}

In the above formula, the parameters can explained as follows:

Po: eNodeB received power per resource block (RB) assuming OdB pathloss.

PMAX: Maximum power that the UE can transmit.

M: Number of assigned resource blocks (RBs)

10 log ₁₀ (M) : Bandwidth of the channel expressed in number of resource blocks.

PL: Estimated Downlink Path Loss

a: Factor to enable or disable Fractional Power Control

(Used to change influence of path loss measurements).

The higher the PL, the higher the power that the UE is allowed to transmit, since any potential interference to base station as measured by the downlink is low.

The most important point is that this sidelink power control scheme only depends on the received path loss of the base station. This means that the transmission power for the sidelink increases as the UE moves away from the base station, but may not necessarily be the optimum power level for the side link itself. This is not suitable for 5G NR sidelink, because what is needed is:

• A power control which is suited to the sidelink itself

• Beam based power control.

• Path loss measurements to be made from other side link users (the wanted user as well as users in adjacent bands - unwanted users) in addition to path loss measurements from the base station.

• Options for closed- loop and open- loop.

With respect to the LTE uplink power control scheme, LTE defines open- and closed-loop power control schemes for uplink power control. The closed-loop scheme can be summarized by the equation below:

UE transmit power = P_Q + a PL + D_TR + f _TPC + 10 log₁₀ M

The additional quantities, which were not already mentioned in the previous equation, are:

• DΊ G : offset for different modulation and coding scheme.

• / (ATPC): closed- loop component of power control.

To set the basic operating point, the UE performs open-loop path loss measurements from the base station, and power control commands (dynamic offset part of the equation) are received from base station.

This is not suitable for the 5G NR sidelink, because what is needed is:

• A power control for the sidelink not for the uplink

• A beam based power control

• Path loss measurements to be made from other sidelink users (the wanted user as well as users in adjacent bands - unwanted users) in addition to path loss measurements from the base station With respect to the 5G NR UE uplink power control scheme, 5G NR specifies different uplink schemes for beam based power control for different types of signals that the UE can transmit, namely Physical Uplink Shared Channel (PUSCH), physical uplink control channel (PUCCH), sounding reference signal (SRS) or physical random access channel (P- RACH). These schemes take into account beam formed based power control, by signaling to the UE the beam-based resource transmitted by the base station, for which the UE should make the measurements, and the corresponding receiver beam at the UE is then the transmitted beam at the UE which is power controlled.

However these beam-based reference signals are only from the base station and not from other sidelink resources. Therefore, this scheme is also not suitable for the 5G NR sidelink, because what is needed is:

• A sidelink power control for the sidelink, not for the uplink.

• Path loss measurements to be made from other sidelink users (the wanted user as well as users in adjacent bands - unwanted users) in addition to path loss measurements from the base station).

SUMMARY

In view of the above-mentioned shortcomings, the embodiments of the present invention aim to improve the conventional power control schemes. An objective is in particular to provide a wireless communication device for beam-selective transmission power control, and another device, particularly a network device, for supporting the beam-selective transmission power control. Thereby, a transmission power control, which is suitable for a sidelink, is desired. The transmission power control at the UE should be beam-based. The proposed devices should be able to make and use path loss measurements from other sidelinks (wanted and unwanted transmission directions) in addition to path loss measurements from e.g. the network device. Also, the option for implementing both closed- loop and open-loop power control is desired.

Furthermore, for 5G NR sidelink power control, the flexibility that different spatial directions may be combined in different ways is needed as well, and also the possibility to weight the signal and power levels in different ways. The above objective is achieved by the embodiments of the invention as described in the enclosed independent claims. Advantageous implementations of the present invention are further defined in the dependent claims.

In particular, the embodiments of the invention propose a detailed, 5G NR compatible, beam-based sidelink transmission power control scheme, exemplarily for three different types of signal:

• Physical Sidelink Shared Channel (PS-SCH)

• Physical Sidelink Control Channel (PS-CCH)

• Physical Sidelink Sounding Reference (PS-SRS)

Furthermore, the embodiments of the invention allow taking into account beam-formed reference signals from e.g. a network device and from at least one other sidelink (wanted or unwanted transmission direction). In this way, the transmission power for wanted sidelink directions can be optimized, and the signal power radiated in other unwanted transmission directions can be controlled as well.

Five different specific ways to combine these downlink and sidelink beam-formed measurements in a transmission power control equation are presented in embodiments of the invention.

A first aspect of the invention provides a wireless communication device (UE) for performing beam-selective transmission power control, the UE being configured to: receive, particularly from the power control configuring device (PCCD) (i.e. network entity, TRP, gNB etc..), a first parameter of a downlink beam-formed resource from a PCCD to the UE and a second parameter of a sidelink beam- formed resource from a second UE to the UE, measure a first path loss based on the first parameter and a second path loss based on the second parameter, and determine, based on the first and second path losses and according to a preconfigured determination scheme, a transmission power for a sidelink beam- formed resource to the second UE. The PCCD may be a 5G NR transmit receive point (TRP), a 5G next generation Node B (gNB), an evolved Node B(eNB), a secondary Node B (SeNB), a base station, or a remote radio head (RRH) or another UE. The UE may be a mobile device, e.g. phone, but may particularly be installed at or in a vehicle e.g. car. That is, the sidelink beam-formed resource may be related to a V2V link. A beam-formed resource may be a transmission beam or beam pair (beam pair = transmission beam at transmission device together with corresponding receiving beam at receiving device) or the like. The preconfigured scheme may be a formula or algorithm implemented at the UE, which yields - based on the path losses - an optimized transmission power for the side-link beam formed resource to the second UE (wanted sidelink transmission direction).

The beamforming at the UE may be formed by any kind of beam-forming method (i.e. digital, RF, hybrid beam-forming) and the different beamforming directions at the UE may be different beam directions from a single beam-forming array, panel or antenna element, or from one or more beam-forming arrays, panels, or antenna elements. Furthermore, in some implementations, each beam-forming array, panel or antenna elements could also form a single fixed beam directions. A panel may be defined as a set of co-located antenna elements.

The UE of the first aspect is enabled to perform a transmission power control suitable for the sidelink, e.g. 5G NR side link, and beam-based, i.e. per beam.

In an implementation form of the first aspect, the wireless communication device is further configured to determine, based on the first and second path losses, a transmission power for an uplink beam formed resource to the PCCD.

Accordingly, a transmission power control at the UE is also enabled (and optimized) for the uplink beam-formed resource to the PCCD (unwanted transmission direction), or any other supporting device. That is, interference to the uplink channel, when transmitting to the second UE via the sidelink channel, can be avoided.

In an implementation form of the first aspect, a spatial direction at the UE associated with the downlink received beam-formed resource from the PCCD to the UE corresponds to a spatial direction associated with the uplink beam- formed resource to the PCCD. Thus, by measuring the path loss for the parameter related to the downlink received beam- formed resource, the transmission power control for the uplink beam-formed resource to the PCCD can be accurately performed.

In an implementation form of the first aspect, a spatial direction at the UE associated with the sidelink received beam- formed resource from the second UE to the UE corresponds to a spatial direction associated with the sidelink beam- formed resource to the second UE.

Thus, by measuring the path loss for the parameter related to the sidelink received beam- formed resource, the transmission power control for the sidelink beam- formed resource to the second UE can be accurately performed.

In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power based on one or more predetermined weighting factors respectively applied to the first path loss and/or to the second path loss.

Accordingly, the flexibility that different spatial directions may be combined in different ways is obtained.

In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power based on a minimum of the weighted first path loss and the weighted second path loss.

In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power based on predetermined target transmission powers predefined for the zero path losses for the downlink beam-formed resource from the PCCD to the UE and the sidelink beam-formed resource from the second UE to the UE respectively.

Accordingly, the flexibility that different spatial directions may be combined in different ways and also the possibility to weight the signal and power levels in different ways is fully enabled. In an implementation form of the first aspect, the wireless communication device is further configured to receive a third parameter of a sidelink beam-formed resource from a third UE to the UE, measure a third path loss based on the third parameter, and determine, based on one, some, or all the measured path losses, the transmission power for the sidelink beam- formed resource to the second UE and/or a sidelink beam-formed resource to the third UE.

Thus, the UE of the first aspect is able to make and use path loss measurements from other sidelinks (wanted and/or unwanted transmission directions) in addition to path loss measurements from the PCCD.

In an implementation form of the first aspect, the wireless communication device is further configured to determine, based on the one, some, or all the measured path losses, a transmission power for an uplink beam formed resource to the PCCD.

In an implementation form of the first aspect, the sidelink beam-formed resource to the second UE is associated with a spatial direction for transmission, and the sidelink beam- formed resource to the third UE is associated with a further spatial direction for transmission.

In an implementation form of the first aspect, the sidelink beam-formed resource to the second UE is associated with a spatial direction for transmission, and the sidelink beam- formed resource to the third UE associated with a further spatial direction for transmission is decreased, in particular such that the sidelink beam-formed resource has lower transmission power than the sidelink beam-formed resource to the second UE.

In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power based on predetermined weighting factors respectively applied to the second path loss and the third path loss.

Thus, the transmission power control scheme allows weighting different sidelinks differently, thus adding more flexibility. In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power based on a predetermined collective function applied to the second path loss and the third path loss.

This is in particular an advantage in case of multicasting or groupcasting, when beams to multiple receiving UEs are formed simultaneously.

In an implementation form of the first aspect, the predetermined collective function comprises a mean, a median, a minimum, a maximum, a sum, or a weighted sum of the second path loss and the third path loss.

In an implementation form of the first aspect, the wireless communication device is further configured to determine the transmission power for transmission on a Physical Sidelink Shared Channel, PS-SCH, Physical Sidelink Control Channel, PS-CCH, and/or Physical Sidelink Sounding Reference, PS-SRS.

In an implementation form of the first aspect, the preconfigured determination scheme is an open-loop scheme based only on path loss measurements, or the preconfigured determination scheme is a closed-loop scheme based on path loss measurements and one or more power control commands received by the UE, particularly from the PCCD.

A second aspect of the invention provides a device for supporting beam-selective transmission power control performed by a wireless communication device (UE) the device being configured to transmit, particularly to the UE, a first parameter of a downlink beam- formed resource from the device to the UE and a second parameter of a sidelink beam- formed resource from a second UE to the UE.

In an implementation form of the second aspect, the device is further configured to: transmit, particularly to the UE, a third parameter of a sidelink beam- formed resource from a third UE to the UE, and/or transmit, particularly to the UE, one or more power control commands.

The device of the second aspect supports the transmission power control scheme at the UE of the first aspect, and thus all the above-mentioned effects and advantages. A third aspect of the invention provides a method for performing beam-selective transmission power control at a wireless communication device (UE), the method comprising: receiving, particularly from a power control configuring device (PCCD), a first parameter of a downlink beam-formed resource from the PCCD to the UE and a second parameter of a sidelink beam-formed resource from a second UE to the UE, measure a first path loss based on the first parameter and a second path loss based on the second parameter, determine based on the first and second path losses and according to a preconfigured determination scheme, a transmission power for a sidelink beam-formed resource from the UE to the second UE.

In an implementation form of the third aspect, the method comprises determining, based on the first and second path losses, a transmission power for an uplink beam formed resource to the PCCD.

In an implementation form of the third aspect, a spatial direction at the UE associated with the downlink received beam-formed resource from the PCCD to the UE corresponds to a spatial direction associated with the uplink beam- formed resource to the PCCD.

In an implementation form of the third aspect, a spatial direction at the UE associated with the sidelink received beam- formed resource from the second UE to the UE corresponds to a spatial direction associated with the sidelink beam- formed resource to the second UE.

In an implementation form of the third aspect, the method comprises determining the transmission power based on one or more predetermined weighting factors respectively applied to the first path loss and/or to the second path loss.

In an implementation form of the third aspect, the method comprises determining the transmission power based on a minimum of the weighted first path loss and the weighted second path loss.

In an implementation form of the third aspect, the method comprises determining the transmission power based on predetermined target transmission powers predefined for the zero path losses for the downlink beam- formed resource from the PCCD to the UE and the sidelink beam- formed resource from the second UE to the UE respectively.

In an implementation form of the third aspect, the method comprises receiving a third parameter of a sidelink beam- formed resource from a third UE to the UE, measuring a third path loss based on the third parameter, and determining, based on one, some, or all the measured path losses, the transmission power for the sidelink beam- formed resource to the second UE and/or a sidelink beam-formed resource to the third UE.

In an implementation form of the third aspect the method further comprises determining, based on the one, some, or all the measured path losses, a transmission power for an uplink beam formed resource to the PCCD.

In an implementation form of the third aspect, the sidelink beam-formed resource to the second UE is associated with a spatial direction for transmission, and the sidelink beam- formed resource to the third UE is associated with a further spatial direction for transmission.

In an implementation form of the third aspect, the sidelink beam-formed resource to the second UE is associated with a spatial direction for transmission, and the sidelink beam- formed resource to the third UE associated with a further spatial direction for transmission is decreased, in particular such that the sidelink beam-formed resource has lower transmission power than the sidelink beam-formed resource to the second UE.

In an implementation form of the third aspect, the method further comprises determining the transmission power based on predetermined weighting factors respectively applied to the second path loss and the third path loss.

In an implementation form of the third aspect, the method further comprises determining the transmission power based on a predetermined collective function applied to the second path loss and the third path loss. In an implementation form of the third aspect, the predetermined collective function comprises a mean, a median, a minimum, a maximum, a sum, or a weighted sum of the second path loss and the third path loss.

In an implementation form of the third aspect, the method further comprises determining the transmission power for transmission on a Physical Sidelink Shared Channel, PS-SCH, Physical Sidelink Control Channel, PS-CCH, and/or Physical Sidelink Sounding Reference, PS-SRS.

In an implementation form of the third aspect, the preconfigured determination scheme is an open-loop scheme based only on path loss measurements, or the preconfigured determination scheme is a closed-loop scheme based on path loss measurements and one or more power control commands received by the UE, particularly from the PCCD.

The method of the third aspect and its implementation forms achieve the same advantages and effects as the device of the first aspect and its respective implementation forms described above.

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. 1A shows a wireless communication device and a (e.g. network) device according to embodiments of the invention.

FIG IB shows a schematic view of a device according to another embodiment of the present invention.

FIG. 2 shows a wireless communication device and a network device according to embodiments of the invention.

FIG. 3 shows a wireless communication device and a network device according to embodiments of the invention.

FIG. 4 shows a wireless communication device and a network device according to embodiments of the invention. FIG. 5 shows a transmission power control method according to an embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1A shows a wireless communication device (UE) 100 configured to perform beam- selective transmission power control, according to an embodiment of the invention. Further, FIG. 1A also shows a device 101 for supporting the beam-selective transmission power control performed by the UE 100, according to another embodiment of the invention. The device 101 may be - as assumed exemplarily in the following description of embodiments - a PCCD which could be a network device, (i.e. a TRP etc.). However, the device 101 could also be another UE or any other entity supporting the power control according to the features described below.

The UE 100 is configured to receive, particularly from the device/ PCCD 101, a first parameter 102 of a downlink beam-formed resource from the PCCD 101 to the UE 100, and a second parameter 103 of a sidelink beam- formed resource from a second UE 104 to the UE 100. Accordingly, the device 101 is configured to transmit, particularly to the UE 100, the first parameter 102 of the downlink beam- formed resource from the device 101 to the UE 100, and the second parameter 103 of the sidelink beam-formed resource from a second UE 104 to the UE 100. The UE 100 may communicate with the second UE 104 via a sidelink as indicated by the dashed line. The UE 100 may communicate with the device/ PCCD 101 via downlink/uplink (or another sidelink if the device 101 is another UE) as indicated by the dashed line.

The UE 100 is further configured to measure a first path loss 105 based on the first received parameter 102, and to measure a second path loss 106 based on the second received parameter 103. The path loss measurements 105, 106 may be carried out by the UE 100 in a conventional manner, i.e. as known from the prior art.

Then, the UE 100 is configured to determine, based on the first and second path losses 105, 106, and according to a preconfigured determination scheme 107, a transmission power 108 for a sidelink beam- formed resource to the second UE 104. The preconfigured determination scheme 107 may be at least one algorithm or formula, which is preinstalled at the UE 100. The UE 100 may be able to choose an algorithms or formula from multiple algorithms or formulas preconfigured at the UE 100, e.g. depending on the type of links, for which the pass losses were measured, or according to different embodiments of the invention as described below.

In exemplary embodiments of the invention, a transmission power control for the 5G NR beam-based sidelink is considered for three different types of signal, namely: Physical Sidelink Shared Channel (PS-SCH), Physical Sidelink Control Channel (PS-CCH), Physical Sidelink Sounding Reference (PS-SRS). For each of these types of signals, an example beam-based sidelink power control equation is proposed (i.e. as the preconfigured determination scheme 107) in the following (based on modified versions of 5G NR uplink beam based equations). In particular, these equations 107 determine how the measured path losses 105, 106 from the different beam-formed resources, i.e. from the device 101 and from one or different sidelink resources, can be combined and weighted in different ways, in order to implement the beam-based sidelink transmission power control to the second UE 104.

Fig. IB shows a schematic view of a user device according to another embodiment of the present invention. As can be seen from the figure different beamforming at the device may correspond to different beam directions. Different beamformings may be achieved from a single beam- forming array, a panel or antenna element on the device. Alternatively, beamformings may be achieved using one or more beam- forming arrays, panels or antenna elements on different locations of the device. Furthermore, in some implementations, each beam- forming array, panel or antenna element on the device, could also form a single fixed beam (direction). A panel may be defined as a set of co-located antenna elements.

Fig. IB show an example of three possible scenarios in which the UE is a vehicle. In 201 different beam directions are formed using a single beam-forming array, a panel or an antenna element located at a single position. In 202 different beam directions are formed using multiple beam-forming arrays, panels or antenna elements, which are at different locations on the vehicle. In 203 a scenario is illustrated, in which fixed beams are formed using multiple beam-forming arrays, panels or antenna elements at different locations of the vehicle.

Although Fig. IB illustrates the different scenarios with reference to a car, it is clear that this is only one possible example of a UE and the spatial filters described above may also be embodied in different types of UEs, such as for instance a mobile phone or any vehicle.

FIG. 2 shows a UE 100 and a device 101 according to embodiments of the invention, which build on the UE 100 and device 101 shown in FIG. 1A . Same elements in FIG. 1A and FIG. 2 are labelled with the same reference signs and function likewise. That is, also in FIG. 2, the device 101 provides the parameters 102/103 to the UE 100, and the UE 100 determines the transmission power 108 for the side link beam- formed resource to the second UE 104. The device 101 may again be a PCCD, like a TRP.

FIG. 2 shows in particular the basic concept of the beam-based transmission power control scheme performed by the UE 100. The UE 100, of which the transmission power 108 is to be power controlled at least for sidelink beam- formed resource to the second UE (104), but optionally also for the uplink beam formed resource to the device 101, is informed about the parameter 102 of the downlink beam- formed resource from the device 101 (c/d) and about the parameter 103 of the sidelink beam- formed resource from the second UE 104 (c/s). These parameters 102 and 103 are at least taken into account for the path loss measurements 105 and 106. The parameter 102 may refer to a resource from Channel State Information-Reference Signal (CSI-RS) signal or a Synchronization Signal Block (SSB) signal transmitted by the base station (Uu link). The parameter 103 may be a sidelink CSI- RS or sidelink SSB resource. The downlink beam- formed resource from the device 101 (here a Uu downlink from a base station) corresponds to an unwanted spatial transmission direction, while the sidelink beam- formed resource to the second UE 104 corresponds to a wanted spatial transmission direction. As illustrated in FIG. 1A, the UE 100 and second UE 104 may be installed at vehicles, here cars A and B.

Five specific embodiments of the invention are exemplarily described in the following using exemplarily equations (preconfigured determination schemes 107) for PS-SCH, but all these five embodiments can be applied to PS-CCH or PS-SRS as well (and indeed also to other types of signals not explicitly defined here). Further, closed-loop power control and open-loop power control embodiments are described. a) PS-SCH closed-loop power control

For the PS-SCH, the standard power control equation for the 5G NR physical uplink shared channel (PU-SCH) - see‘3 GPP TS 38.213 V15.1.0 (2018-03), Section 7, Uplink Power Control’ - is modified, in particular for the sidelink with the additional parameters and resources needed for the sidelink to use it for the 5G NR PS-SCH. This is shown below in equation (1), which shows a baseline modification. The relevant modifications and changes are shown in grey shading in equation (1). Other modifications not highlighted include changing the subscripts to pssch.

Ppssch,f ,c (h j l> ⁽Jd> ¾)

The path loss measurements inside the min (.) expression includes the path loss measurements 105, 106 for the side link PLf_c(q_s) to the second UE 104 and its own weighting factor alpha a/._c j) . The equation (1) is a beam-based equation, which means the transmission power for the spatial directions, for which the UE 100 receives the indicated resources (q _i and q_s) are the ones which are power controlled according to the equation (1). By including both the sidelink beam-formed resource and the downlink beam-formed resource, the transmission in both of these directions may be controlled.

FIG. 3 shows a UE 100 and device 101 according to embodiments of the invention, which build on the UE 100 and device 101 shown in FIG. 1A and FIG. 2. Same elements in FIG. 1A, FIG. 2 and FIG. 3 are labelled with the same reference signs and function likewise. That is, also in FIG. 3, the device 101 provides the parameters 102/103 to the UE 100, and the UE 100 determines the transmission power 108 for at least the sidelink beam- formed resource to the second UE 104.

As shown in FIG. 3, the UE 100 may particularly receive a third parameter 301 ofa sidelink beam- formed resource from at least one third UE 300 to the UE 100. The UE 100 may measure a third path loss based on the third parameter 301, and may determine, based on one, some, or all the measured path losses, the transmission power 108 for the sidelink beam- formed resource to the second UE 104 and/or a sidelink beam- formed resource to the third UE 300. The sidelink beam-formed resource to the third UE 300 is thereby associated with a further spatial direction for transmission. In FIG. 3, the sidelink beam- formed resource from the third UE 300 relates to a wanted direction of transmission.

This situation may be reflected by a first modification of the above equation (1), namely to include the possibility that there are n multiple sidelink resources {q_si to q_sn) to serve. This may advantageously be used for sidelink multicasting / groupcasting, or to manage wanted or unwanted transmissions in different sidelink directions. The changes for this first modification are shown in the equation (2) below:

The UE 100 may also determine the transmission power 108 based on predetermined target transmission powers predefined for the zero path losses for at least the downlink beam- formed resource from the device 101 to the UE 100 and the sidelink beam- formed resource from the second UE 104 to the UE 100 respectively.

This may be reflected by a second modification of the equation (1). Namely, the sidelink and downlink beam formed resources in the min (.) part of the equation, may have different target transmission powers Po (for zero path loss) as specifically illustrated in the equation below as P₀d,_Psssch,fc and P₀s,_Psssch,fc respectively. In this way, the target power, which is sent in each of these spatial directions, can be controlled. This is particularly useful, if one of the spatial directions is an unwanted direction - as illustrated in FIG. 3 with respect to the further UE 300. This is shown below in equation (3):

The UE 100 may also be configured to determine the transmission power 108 based on one or more predetermined weighting factors, respectively applied to the first path loss 105 and/or to the second path loss 106.

This may be reflected by a third modification of the equation (1), wherein different target receive powers P_osi,_Psssch,fc, .... Posn,_Pssschj,c, and different weighting factors (alphas) a fc,si(j) · · · o. i.c.sn(j) may be taken into account for multiple sidelink beam- formed resources. This is shown below in equation (4), where only the modified min (.) part of the previous power control equation (3) is shown. This modification is especially useful for sidelink groupcasting / multicasting when there are certain spatial directions, in which the transmission power in wanted and unwanted directions is to be controlled.

An examples of such a scenario is shown in FIG. 4. FIG. 4 shows a UE 100 and device 101 according to embodiments of the invention, which build on the UE 100 and device 101 shown in FIG. 1A, 2 and 3. Same elements in FIG. 1A -4 are labelled with the same reference signs and function likewise. That is, also in FIG. 4, the device 101 provides the parameters 102/103 to the UE 100, and the UE 100 determines the transmission power 108 for the sidelink beam- formed resource to the second UE 104.

Like in FIG. 3, the UE 100 shown in FIG. 4 may receive a third parameter 301 of a sidelink beam-formed resource from at least one third UE 300 to the UE 100. The sidelink beam- formed resource to the third UE 300 is associated with a further spatial direction for transmission. However, in contrast to FIG. 3, the sidelink beam- formed resource from the third UE 300 relates in FIG. 4 to an unwanted direction of transmission.

The UE 100 may also determine the transmission power 108 based on a predetermined collective function applied to the second path loss 106 and the third path loss. This may be reflected by a fourth modification of equation (1), wherein a set of sidelink beam- formed resources could be bundled together in the collective function f (.) in the min (.) part of the equation (1). This may be useful for multicasting or groupcasting, wherein beams to multiple receiving UEs may have to be formed simultaneously, and the performance for the best or worse set of those multiple receiving UEs in the group should be optimized.

The collective function f (.) can be many different types of expressions, which could include: Mean (.), Minimum (.), Max (.), Sum (.), Median (.), Weighted sum (.), etc. b) PS-SCH open-loop Above under a), the proposal for the closed-loop power control of the PS-SCH was described. For the open-loop version of the power control, a baseline modification is proposed of the 5G NR beam based power control for the physical uplink shared channel (PUSCH). The baseline modifications is shown in the equation (6) below (grey shaded again the relevant modifications):

This is very similar to the changes proposed above to the closed- loop version of the power control for PS-SCH. The key difference between the closed-loop and open-loop version of the power control is that the dynamic offset for different modulation and coding schemes (MCS) D _TF,f_,c which changes with link adaptation and the power control feedback commands

are not included.

Accordingly, the preconfigured determination scheme 107 may be a closed- loop scheme based on path loss measurements and one or more power control commands received by the UE 100, particularly from the PCCD 101. In addition to the baseline modification described above for the open-loop power equation (6), all of the first to fourth modifications described for the PS-SCH closed-loop equation can be applied as well. c) PS-CCH closed- and open-loop

For the PS-CCH, it is also proposed to use the modified version of the 5G NR physical uplink control channel (PU-CCH). The key baseline modification for the closed- and open- loop are shown below in the equations (7) and (8), respectively. Baseline modification to the closed loop equation (7):

Baseline modification to the open loop equation (8):

In addition to these baseline modifications, all of the above-proposed first to fourth modifications can also be applied here. d) PS-SRS closed and open loop

For the PS-SRS, it is also proposed to use the modified version of the 5G NR SRS (SRS) power control equations. The key baseline modifications for the closed- and open- loop are shown below in equations (9) and (10).

Baseline modification to closed-loop equation:

PpSSRS,b,f,c (.i> Ru> Rd> Rs) —

Baseline modifications to open-loop equation:

PpSSRS,b,f,c (ό Ru> Rd> R$)

In addition to these baseline modifications, all of the above-proposed first to fourth modifications can also be applied here.

The key modifications for all of these signal types is the changes made to include the downlink (DL) and sidelink (SL) measurements and how they are weighted in the power control equation. In particular, five different variations of how to use downlink (DL) and sidelink (SL) measurements for each of the above-proposed modifications were presented: i) Minimum of (one downlink, one sidelink) - baseline modification.

ii) Different target powers for downlink and sidelink(s) - first modification.

iii) Minimum of (one DL and multiple sidelinks) - second modification.

iv) Different alphas for different sidelinks - third modification.

v) Collective function f (.) of a set of a sidelink path losses and associated parameters - fourth modification.

Throughout the above description of embodiments, the present 3 GPP 5G NR uplink power control equations was used as a basis, and was modified for different signal types to illustrate the key points. Traditionally these equations are for systems, in which the control (CCH) and shared channel (SCH) (data parts) are time domain multiplexed (TDM). Therefore, the power control and the bandwidth can be easily separated for these separate parts. However, it is possible that the control and data parts may be multiplexed in the frequency domain.

In all of the above equations, the bandwidth part of the equations may also include both the parts from the control and data parts. For example, if taking the physical sidelink control channel as an example, the bandwidth part may change in equation (1) from:

... + 101og₁₀(2 ^m.MZ^ ·

To:

This is, however, just an example. FIG. 5 shows a method 500 according to an embodiment of the invention. The method 500 is for performing beam-selective transmission power control at a UE 100. The method 500 may particularly be carried out by the UE 100 of FIG. 1A-4.

The method includes: a step 501 of receiving, particularly from a TRP 101 a first parameter 102 of a downlink beam- formed resource from the TRP 101 to the UE 100 and a second parameter 103 of a sidelink beam-formed resource from a second UE 104 to the UE 100; a step 502 of measuring a first path loss 105 based on the first parameter 102 and a second path loss 106 based on the second parameter 103; and a step 503 of determining, based on the first and second path losses 105, 106, and according to a preconfigured determination scheme 107, a transmission power 108 for a sidelink beam- formed resource from the UE 100 to the second UE 104.

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.

Claims

1. Wireless communication device, UE, (100) for performing beam-selective transmission power control, the UE (100) being configured to:

receive, particularly from a power control configuring device, PCCD, a first parameter (102) of a downlink beam-formed resource from the PCCD, (101) to the UE (100) and a second parameter (103) of a sidelink beam-formed resource from a second UE (104) to the UE (100),

measure a first path loss (105) based on the first parameter (102) and a second path loss (106) based on the second parameter (103), and

determine, based on the first and second path losses (105, 106) and according to a preconfigured determination scheme (107), a transmission power (108) for a sidelink beam- formed resource to the second UE (104).

2. Wireless communication device (100) according to claim 1, further configured to: determine, based on the first and second path losses (105, 106), a transmission power for an uplink beam- formed resource to the PCCD (101).

3. Wireless communication device (100) according to claim 2, wherein:

a spatial direction at the UE (100) associated with the downlink received beam- formed resource from the PCCD (101) to the UE (100) corresponds to a spatial direction associated with the uplink beam-formed resource to the PCCD (101).

4 Wireless communication device (100) according to one of the claims 1 to 3, wherein;

a spatial direction at the UE (100) associated with the sidelink received beam- formed resource from the second UE (104) to the UE (100) corresponds to a spatial direction associated with the sidelink beam-formed resource to the second UE (104).

5. Wireless communication device (100) according to one of the claims 1 to 4, configured to:

determine the transmission power (108) based on one or more predetermined weighting factors respectively applied to the first path loss (105) and/or to the second path loss (106).

6. Wireless communication device (100) according to claim 5, configured to:

determine the transmission power (108) based on a minimum of the weighted first path loss (105) and the weighted second path loss (106).

7. Wireless communication device (100) according to one of the claims 1 to 6, configured to:

determine the transmission power (108) based on predetermined target transmission powers predefined for the zero path losses for the downlink beam-formed resource from the PCCD (101) to the UE (100) and the sidelink beam-formed resource from the second UE (104) to the UE (100) respectively.

8. Wireless communication device (100) according to one of the claims 1 to 7, further configured to:

receive a third parameter (301) of a sidelink beam- formed resource from a third UE (300) to the UE (100),

measure a third path loss based on the third parameter (301), and

determine, based on one, some, or all the measured path losses, the transmission power (108) for the sidelink beam- formed resource to the second UE (104) and/or a sidelink beam- formed resource to the third UE (300).

9. Wireless communication device (100) according to claim 8, further configured to: determine, based on the one, some, or all the measured path losses, a transmission power for an uplink beam formed resource to the PCCD (101).

10. Wireless communication device (100) according to claim 8 or 9, wherein:

the sidelink beam-formed resource to the second UE (104) is associated with a spatial direction for transmission, and

the sidelink beam- formed resource to the third UE (300) is associated with a further spatial direction for transmission.

11 Wireless communication device (100) according to claim 8 or 9, wherein:

the sidelink beam-formed resource to the second UE (104) is associated with a spatial direction for transmission, and the sidelink beam-formed resource to the third UE (300) associated with a further spatial direction for transmission is decreased, in particular such that the sidelink beam- formed resource has lower transmission power than the sidelink beam-formed resource to the second UE (104).

12. Wireless communication device (100) according to one of the claims 8 to 11, configured to:

determine the transmission power (108) based on predetermined weighting factors respectively applied to the second path loss (105) and the third path loss.

13. Wireless communication device according to one of the claims 8 to 12, configured to:

determine the transmission power (108) based on a predetermined collective function applied to the second path loss (106) and the third path loss.

14. Wireless communication device (100) according to claim 13, wherein:

the predetermined collective function comprises a mean, a median, a minimum, a maximum, a sum, or a weighted sum of the second path loss (106) and the third path loss.

15. Wireless communication device (100) according to one of the claims 1 to 14, configured to:

determine the transmission power (108) for transmission on a Physical Sidelink Shared Channel, PS-SCH, Physical Sidelink Control Channel, PS-CCH, and/or Physical Sidelink Sounding Reference, PS-SRS.

16. Wireless communication device (100) according to one of the claims 1 to 15, wherein:

the preconfigured determination scheme (107) is an open- loop scheme based only on path loss measurements, or

the preconfigured determination scheme (107) is a closed-loop scheme based on path loss measurements and one or more power control commands received by the UE (100), particularly from the PCCD (101).

17. Device ( 101 ) for supporting beam-selective transmission power control performed by a wireless communication device, UE, (100) the device (101) being configured to:

transmit, particularly to the UE (100), a first parameter (102) of a downlink beam- formed resource from the device (101) to the UE (100) and a second parameter (103) of a sidelink beam- formed resource from a second UE (104) to the UE (100).

18. Device (101) according to claim 17, further configured to:

transmit, particularly to the UE (100), a third parameter of a sidelink beam- formed resource from a third UE (300) to the UE (100), and/or

transmit, particularly to the UE (100), one or more power control commands.

19. Method (500) for performing beam-selective transmission power control at a wireless communication device, UE, (100) the method (500) comprising:

receiving (501), particularly from a power control configuration device, PCCD, a first parameter (102) of a downlink beam-formed resource from the PCCD, (101) to the UE (100) and a second parameter (103) of a sidelink beam-formed resource from a second UE (104) to the UE (100),

measuring (502) a first path loss (105) based on the first parameter (102) and a second path loss (106) based on the second parameter (103),

determining (503), based on the first and second path losses (105, 106) and according to a preconfigured determination scheme (107), a transmission power (108) for a sidelink beam- formed resource from the UE (100) to the second UE (104).