WO2021148031A1

WO2021148031A1 - Transmission of reference signal for positioning

Info

Publication number: WO2021148031A1
Application number: PCT/CN2021/073642
Authority: WO
Inventors: Li Guo
Original assignee: Guangdong Oppo Mobile Telecommunications Corp., Ltd.
Priority date: 2020-01-23
Filing date: 2021-01-25
Publication date: 2021-07-29

Abstract

A method for transmitting a reference signal from a terminal device comprises: receiving a path loss reference signal; determining whether or not a value of a parameter calculated from receiving the path loss reference signal exceeds a threshold to thereby determine whether the terminal device is able to accurately measure a path loss based on the received path loss reference signal; based on the determination, calculating a transmit power for transmission of a reference signal for positioning; and transmitting a reference signal for positioning at the calculated transmit power.

Description

TRANSMISSION OF REFERENCE SIGNAL FOR POSITIONING

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of United States Patent Application No. 62/965,148, filed on January 23, 2020, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The present application relates to the field of communications, and more particularly to a method, terminal device, and network device for determining the uplink transmit power for transmission of a sounding reference signal resource for positioning.

BACKGROUND

An example communications system is the fifth generation (5G) New Radio (NR) system (5G/NR) . In 5G NR, uplink power control of a sounding reference signal (SRS) transmission is supported.

Uplink power control is used to determine a suitable amount of power to be used by a terminal device (such as a user equipment (UE) ) to transmit an SRS to a base station (such as a gNB) . In one system, a base station transmits a certain reference signal at a known power to the terminal device. The terminal device measures the received power of the reference signal and uses it to determine the path loss between the terminal device and the base station. The terminal device uses the determined path loss to calculate a power with which the terminal device can transmit a signal (such as an SRS) to the base station.

The power control on SRS transmission specified in release 15 specification (3GPP TS 38.213 V. 15.5.0) is based on the method of fractional power control and the path loss between the UE and the serving gNB. In the current design, one UE can be configured with one or more SRS resource sets and each SRS resource set can be configured with K ≥ 1 SRS resources. Uplink power control parameters are configured per SRS resource set.

One SRS resource set q _s is configured with the following power control parameters:

- α (q _s) : path loss compensation factor configured for the SRS resource set q _s.

- P ₀ (q _s) : open-loop receive power target configured for the SRS resource set q _s.

- q _d: path loss reference signal, it is one index of a channel state information reference signal (CSI-RS) resource or synchronization signal physical broadcast channel (SS/PBCH) block transmitted by the serving gNB configured for the SRS resource set q _s.

- srs-PowerControlAdjustmentStates to indicate whether same power control adjustment state for SRS and physical uplink shared channel (PUSCH) transmission or separate power control adjustment shall be used for the SRS resource set.

The UE measures the CSI-RS resource or SS/PBCH block configured as a path loss reference signal to estikmate the path loss between the UE and the serving gNB. If a UE transmits SRS on an active uplink bandwidth part (UL BWP) b of carrier f of serving cell c using SRS power control adjustment state with index l, the UE calculates the transmit power (in dBm) for transmission in SRS transmission occasion i in an SRS resource in the set q _s as:

where,

- P _CMAX, f, c (i) is the UE configured maximum output power for carrier f of serving cell c in SRS transmission occasion i

- P _{O_SRS, b, f, c} (q _s) is provided by p0 for active UL BWP b of carrier f of serving cell c and SRS resource set q _s provided by SRS-ResourceSet and SRS-ResourceSetId; if p0 is not provided, P _{o_SRS, b, f, c} (q _s) =P _{O_NOMINAL_PUSCH, f, c} (0)

- M _{SRS, b, f, c} (i) is an SRS bandwidth expressed in terms of a number of resource blocks for SRS transmission occasion i on active UL BWP b of carrier f of serving cell c and μ is a subcarrier spacing (SCS) configuration

- α _{SRS, b, f, c} (q _s) is provided by alpha for active UL BWP b of carrier f of serving cell c and SRS resource set q _s

- PL _b, f, c (q _d) is a downlink path loss estimate in dB calculated by the UE using the reference signal (RS) resource index q _d for the active downlink (DL) BWP of serving cell c and SRS resource set q _s. The RS resource index q _d is provided by the value of pathlossReferenceRS that is associated with the SRS resource set q _s and is either a synchronization signal block (ssb) -Index providing a SS/PBCH block index or a csi-RS-Index providing a CSI-RS resource index

- If the UE is not provided with the pathlossReferenceRS or before the UE is provided with dedicated higher layer parameters, the UE calculates PL _b, f, c (q _d) using a RS resource obtained from the SS/PBCH block that the UE uses to obtain a master information block (MIB)

- If the UE is provided with pathlossReferenceLinking, the RS resource is on a serving cell indicated by a value of pathlossReferenceLinking

- For the SRS power control adjustment state for active UL BWP b of carrier f of serving cell c and SRS transmission occasion i

- h _b, f, c (i, l) =f _b, f, c (i, l) , where f _b, f, c (i, l) is the current PUSCH power control adjustment state.

The downlink path loss PL _b, f, c (q _d) is calculated by the UE using an RS resource index q _dconfigured to the SRS resource set. The RS resources index q _d is provided by the higher layer parameter pathlossReferenceRS associated with the SRS resource set q _s and is either a ssb-Index providing a SS/PBCH block index or a csi-RS-Index providing a CSI-RS resource index.

If the UE is not provided with the path loss RS parameter pathlossReferenceRS, a fallback procedure is used to calculate the downlink path loss used in uplink power control. The UE estimates downlink path loss using an RS resource obtained from the SS/PBCH block that the UE uses to obtain MIB.

In the specified method, both open-loop and closed-loop power control are supported. Open-loop power control on SRS transmission is based on the path loss between the UE and the serving gNB that is calculated based on measuring downlink RS q _d configured to the SRS resource set. Closed-loop power control (control involving the parameter h _b, f, c (i, l) ) is based on the power adjust command sent by the serving gNB. Separate closed-loop power control for SRS is signaled through DCI format 2_3.

The SRS for positioning is supported. The SRS for positioning can be transmitted toward the serving cell or a non-serving (neighbor) cell. Thus, the path loss reference signal for determining uplink transmit power of an SRS for positioning can be a downlink reference signal of the serving cell or a synchronization signal block (SSB) or downlink positioning reference signal (DL PRS) resource from a neighbor cell.

The UE determines the uplink transmit power (in dBm) for an SRS resource for positioning as follows:

where,

- P _{O_SRS, b, f, c} (q _s) and α _{SRS, b, f, c} (q _s) are provided by higher layer parameters p0 and alpha respectively, for active UL BWP b of carrier f of serving cell c, and SRS resource set q _sas indicated by SRS-ResourceSetId from SRS-ResourceSet, and

- PL _b, f, c (q _d) is a downlink path loss estimate in dB calculated by the UE in the case of an active DL BWP of a serving cell c, using RS resource indexed q _d in a serving or non-serving cell for SRS resource set q _s. A configuration for RS resource index q _d associated with SRS resource set q _s is provided by pathlossReferenceRS

- if an ssb-Index is provided, referenceSignalPower is provided by ss-PBCH-BlockPower

- if a dl-PRS-ResourceId is provided, referenceSignalPower is provided by dl-PRS-ResourcePower.

If the UE determines that the UE is not able to accurately measure the downlink path loss (PL _b,f, c (q _d) ) , the UE estimates the downlink path loss (PL _b, f, c (q _d) ) using an RS resource obtained from the SS/PBCH block that the UE uses to obtain the MIB.

SUMMARY

Embodiments provide a method, a terminal device, and computer code for transmitting a reference signal for positioning.

According to an aspect, there is provided a method for transmitting a reference signal from a terminal device, the method comprising: receiving a path loss reference signal; determining whether or not a value of a parameter calculated from receiving the path loss reference signal exceeds a threshold to thereby determine whether the terminal device is able to accurately measure a path loss based on the received path loss reference signal; based on the determination, calculating a transmit power for transmission of a reference signal for positioning; and transmitting a reference signal for positioning at the calculated transmit power.

The method may further comprise: determining whether the path loss reference signal is received from a serving network device or a non-serving network device.

The method may comprise determining whether or not the value of the parameter calculated from receiving the path loss reference signal exceeds the threshold in response to determining that the path loss reference signal is received from a non-serving network device.

The method may comprise responding to determining that the path loss reference signal is from a non-serving network device and that the value of the parameter calculated from receiving the path loss reference signal does not exceed the threshold by calculating the transmit power of the reference signal for positioning by: estimating path loss using a reference signal resource received from a serving network device; calculating a base transmit power based on the estimated path loss; and adding a power offset to the preliminary transmit power to provide the calculated transmit power.

The calculating the transmit power of the reference signal for positioning may comprise: estimating path loss using a reference signal resource received from a serving network device; calculating a base transmit power based on the estimated path loss; and adding a power offset to the base transmit power to provide the calculated transmit power.

The value of the power offset may be determined based on configuration information received by the terminal device.

The value of the power offset may be determined by the terminal device.

The value of the power offset may be selected from a plurality of different values stored in the terminal device.

The value of the power offset may be selected from a plurality of different values stored in the terminal device based on the value of the parameter calculated from receiving the path loss reference signal.

The plurality of different values may include a value of 0 dB.

The method may comprise the terminal device transmitting the reference signal for positioning on an active uplink bandwidth part b of carrier f of a serving network device c using SRS power control adjustment state with index l, and calculating the transmit power on occasion i in an SRS resource in the set q _s using:

wherein:

P _CMAX, f, c (i) is the terminal device configured maximum output power for carrier f of serving network device c on transmission occasion i,

P _{O_SRS, b, f, c} (q _s) and α _{SRS, b, f, c} (q _s) are provided by higher layer parameter p0 and alpha respectively, which are the target received power level and power adjustment factor,

PL _b,f, c (q _d) is a downlink path loss calculated by the terminal device using a reference signal resource obtained from the synchronization signal block that the terminal device uses to obtain a master information block,

M _{SRS, b, f, c} (i) is a bandwidth expressed in number of resource blocks for transmission of the reference signal for positioning, and

Δ is the power offset.

The parameter may be the received power of the path loss reference signal, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the received power of the path loss reference signal being below a first threshold.

The parameter may be the received quality of the path loss reference signal, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the received quality of the path loss reference signal being below a second threshold.

The parameter may be the signal to interference noise ratio of the path loss reference signal, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the signal to interference noise ratio of the path loss reference signal being below a third threshold.

The parameter may be the strength indicator of the path loss reference signal, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the strength indicator of the path loss reference signal being below a fourth threshold.

The parameter may be the channel quality indicator of the path loss reference signal, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the channel quality indicator of the path loss reference signal being below a fifth threshold.

The parameter may be the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device to measure, the method may comprise determining that the terminal device is not able to accurately measure the path loss based on the number of transmission instances of the path loss reference signal within the given time period which are available for the terminal device to measure being less than a sixth threshold.

According to another aspect, there is provided a terminal device comprising: a communication unit configured to receive a path loss reference signal; and a processing unit configured to: determine whether or not a value of a parameter calculated from receiving the path loss reference signal exceeds a threshold to thereby determine whether the terminal device is able to accurately measure a path loss based on the received path loss reference signal, based on the determination, calculate a transmit power for transmission of a reference signal for positioning, and control the communication unit to transmit the reference signal for positioning at the calculated transmit power.

The processing unit may be further configured to determine whether the path loss reference signal is received from a serving network device or a non-serving network device.

The processing unit may be configured to determine whether or not the value of the parameter calculated from receiving the path loss reference signal exceeds the threshold in response to determining that the path loss reference signal is received from a non-serving network device.

The processing unit may be configured to respond to determining that the path loss reference signal is from a non-serving network device and that the value of the parameter calculated from receiving the path loss reference signal does not exceed the threshold by calculating the transmit power of the reference signal for positioning by: estimating the path loss using a reference signal resource received from a serving network device; calculating a base transmit power based on the estimated path loss; and adding a power offset to the preliminary transmit power to provide the calculated transmit power.

To calculate the transmit power of the reference signal for positioning, the processing unit may be configured to: estimate the path loss using a reference signal resource received from a serving network device; calculate a base transmit power based on the estimated path loss; and add a power offset to the base transmit power to provide the calculated transmit power.

The processing unit may be configured to determine the value of the power offset based on configuration information received by the communication unit.

The processing unit may be configured to determine the value of the power offset.

The processing unit may be configured to select the value of the power offset from a plurality of different values stored in the terminal device.

The processing unit may be configured to select the value of the power offset from a plurality of different values stored in the terminal device based on the value of the parameter calculated from receiving the path loss reference signal.

The plurality of different values may include a value of 0 dB.

The processing unit may be configured to control the communication unit to transmit the reference signal for positioning on an active uplink bandwidth part b of carrier f of a serving network device c using SRS power control adjustment state with index l, and calculate the transmit power on occasion i in an SRS resource in the set q _s using:

wherein:

Δ is the power offset.

The parameter may be the received power of the path loss reference signal, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the received power of the path loss reference signal being below a first threshold.

The parameter may be the received quality of the path loss reference signal, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the received quality of the path loss reference signal being below a second threshold.

The parameter may be the signal to interference noise ratio of the path loss reference signal, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the signal to interference noise ratio of the path loss reference signal being below a third threshold.

The parameter may be the strength indicator of the path loss reference signal, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the strength indicator of the path loss reference signal being below a fourth threshold.

The parameter may be the channel quality indicator of the path loss reference signal, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the channel quality indicator of the path loss reference signal being below a fifth threshold.

The parameter may be the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device to measure, and the processing unit may be configured to determine that the terminal device is not able to accurately measure the path loss based on the number of transmission instances of the path loss reference signal within the given time period which are available for the terminal device to measure being less than a sixth threshold.

According to another aspect, there is provided a computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out a method.

According to another aspect, there is provided a method for controlling a system comprising a terminal device and a network device, the method further comprising receiving the reference signal for positioning by the network device.

According to another aspect, there is provided a system comprising the terminal device and a network device configured to receive the reference signal for positioning.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic illustration of a system according to embodiments;

Figure 2 shows a schematic illustration of a terminal device according to embodiments;

Figure 3 shows a schematic illustration of a network device according to embodiments;

Figure 4 shows a flowchart of the operation of the terminal device according to some embodiments;

Figure 5 shows a flowchart of the operation of the terminal device according to other embodiments;

Figure 6 shows a flowchart of the operation of the network device according to embodiments; and

Figure 7 shows a message flow procedure between the terminal device and the network device of Figures 2 and 3.

DETAILED DESCRIPTION

Technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings.

These technical solutions may be applied to a 5G NR communication system. For example, they may be used for FR2. FR2 includes frequency bands from 24.25 GHz to 52.6 GHz.

It is to be understood that these technical solutions may also be applied to various communication systems, for example, a Global System of Mobile communication (GSM) , a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS) system, a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a Universal Mobile Telecommunication System (UMTS) , a Worldwide Interoperability for Microwave Access (WiMAX) communication system, and New Radio (NR) or future 5G systems, and the like.

The technical solutions may be applied to a variety of communication systems, for example, an orthogonal frequency division multiplexing (OFDM) system.

A terminal device in the embodiments may refer to a user equipment (UE) , an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user apparatus. The access terminal may be a cellular phone, a cordless phone, an SIP (Session Initiation Protocol) phone, a WLL (Wireless Local Loop) station, a PDA (Personal Digital Assistant) , a handheld device having a wireless communication function, a computing device, or another processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network, or a terminal device in a future evolutional PLMN (Public Land Mobile Network) , and the like. However, the embodiments of the present application are not limited thereto.

A network device in the embodiments of the present application may be a device for communicating with the terminal device. Specifically, the network device may be a Base Transceiver Station (BTS) in a GSM system or a CDMA system, a NodeB (NB) in a WCDMA system, an Evolutional NodeB (eNB or eNodeB) in an LTE system, a cell, a wireless controller, or a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in 5G network (for example, gNB) , or a network device in a future evolutional Public Land Mobile Network (PLMN) , etc. The network device may include a transmission-reception point (TRP) of a base station (for example, a gNB) . However, the embodiments of the present application are not limited thereto.

A transmission point (TP) is a set of geographically co-located transmit antennas (e.g. antenna array (with one or more antenna elements) ) for one cell or part of one cell. Transmission Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, etc. One cell can include one or multiple transmission points. For a homogeneous deployment, each transmission point may correspond to one cell.

A reception point (RP) is a set of geographically co-located receive antennas (e.g. antenna array (with one or more antenna elements) ) for one cell or part of one cell. Reception Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, and so on. One cell can include one or multiple reception points. For a homogeneous deployment, each reception point may correspond to one cell.

A transmission-reception point (TRP) is a set of geographically co-located antennas (e.g. antenna array (with one or more antenna elements) ) supporting TP and/or RP functionality.

A cell is a network device that can be uniquely identified by a terminal device from a (cell) identification that is broadcast over a geographical area from one Radio Access Network (RAN) access point.

For a terminal device in RRC_CONNECTED not configured with carrier aggregation (CA) /dual connectivity (DC) there is only one serving cell comprising of the primary cell. For a terminal device in RRC_CONNECTED configured with CA/DC the term 'serving cells' is used to denote the set of one or more cells comprising of the primary cell and all secondary cells.

A primary cell operates on a primary frequency, in which the terminal device either performs initial connection establishment procedure or initiates connection re-establishment procedure, or the network device indicated as the primary cell in a handover procedure.

A secondary cell operates on a secondary frequency, which may be configured once a Radio Resource Control (RRC) connection is established and which may be used to provide additional radio resources.

A wireless communication network includes one or more fixed base infrastructure units forming a network distributed over a geographical region. As an example, the network device may serve a number of terminal devices within a serving area, for example, a cell, or within a cell sector. In some systems, one or more network devices are coupled to a controller (such as a wireless controller) forming an access network that is coupled to one or more core networks. Base stations (e.g. gNB) are examples of network devices in the wireless network, the serving area of which may or may not overlap with each other.

A communication system in general may include a terminal device and a network device. The network device is configured to provide communication services for the terminal device and access to a core network. The terminal device accesses the network by searching a synchronous signal, broadcast signal and the like transmitted by the network device, thereby communicating with the network.

Figure 1 shows a schematic illustration of a communication system 10 according to embodiments. The system 10 comprises terminal device 100, a first network device 200a and a second network device 200b. As shown in Figure 1, the terminal device 100 and network device 200 can perform uplink transmission (terminal device 100 to network device 200) and downlink transmission (network device 200 to terminal device 100) .

The network devices 200 are configured to provide communication service for the terminal device 100 and access to a core network. The terminal device 100 gains access to the network by searching a synchronous signal, broadcast signal and the like transmitted by at least one of the network devices 200, thereby communication with the network. Arrows shown in Figure 1 may represent uplink/downlink transmission implemented through a cellular link between the terminal device 100 and the network device 200.

It will be appreciated that in practical implementations of embodiments, there may be many such terminal devices 100 and/or network devices 200.

In this embodiment, the communication system 10 is the 5G NR communication system. However, embodiments of the invention are not limited to this and any suitable communication system could be used instead.

In this embodiment, the terminal device 100 is a UE. More specifically, in this embodiment, the terminal device 100 is a smartphone. However, embodiments of the invention are not limited to this and any suitable terminal device 100 capable of communicating with a network device 200 could be used instead. Examples include a PDA, tablet, or other suitable computer devices.

In this embodiment, the network device 200 is a base station. More specifically, the network device 200 is a gNB (or ‘gNodeB’ ) . However, embodiments of the invention are not limited to this and any suitable network device 200 capable of communicating with a terminal device 100 could be used instead.

Figure 2 shows a schematic illustration of the terminal device 100 of the communication system 10 of Figure 1. As shown in Figure 1, the terminal device 100 comprises a communication unit 110 and a processing unit 120.

The communication unit 110 is configured to communicate with the network device 200. More specifically, the communication unit 110 is configured to perform both uplink communication (i.e. terminal device 100 to network device 200) and downlink communication (i.e. network device 200 to terminal device 100)

The processing unit 120 is configured to control the overall functionality of the terminal device 100, including that of the communication 110. This includes controlling the communication unit 110 to perform both uplink and downlink communications, as well as processing signals received through the downlink transmissions.

Figure 3 shows a schematic illustration of the network device 200 of the communication system 10 of Figure 1. As shown in Figure 3, the network device 200 comprises a communication unit 210 and a processing unit 220.

The communication unit 210 is configured to communicate with the terminal device 100. More specifically, the communication unit 210 is configured to perform both uplink communication (i.e. terminal device 100 to network device 200) and downlink communication (i.e. network device 200 to terminal device 100) . The communication unit 21o may be configured to transmit a beam using a first set of reference signal resources or a second set of reference signal resources. The communication unit 210 may be configured to transmit downlink control information (DCI) and/or Radio Resource Control (RRC) configuration information to configure the terminal device 100.

The processing unit 220 is configured to control the overall functionality of the network device 200, including that of the communication unit 210. This includes controlling the communication unit 210 to perform both uplink and downlink communications, as well as processing signals received through the uplink transmissions. The processing unit 220 may be configured to control which set of reference signal resources are transmitted by the communication unit 210.

Figure 4 shows a flowchart operation of the terminal device 100 of Figure 2. Through the flowchart of Figure 4 discussed below, the terminal device 100 can determine if a path loss can be measured accurately based on a path loss reference signal and determine a suitable uplink transmission power for SRS for positioning.

At step S401 of Figure 4, the terminal device 100 receives a reference signal resource from a serving network device 200a. The reference signal resource is obtained from the SS/PBCH block that the terminal device 100 uses to obtain MIB. The reference signal resource is not a path loss reference signal. The reference signal resource may be used to estimate the downlink path loss. The terminal device 100 can use the synchronization signal block (SSB) of the serving network device 200a used to obtain the MIB to estimate the path loss used in uplink power control.

At step S402 of Figure 4 (which is optional) , the terminal device 100 receives configuration information to be configured with one or more SRS resource sets.

The communication unit 110 of the terminal device 100 may comprise a plurality of receiving units. A receiving unit may be a panel. A panel includes a group of physical antennas, and each panel has an independent radio frequency channel. The terminal device 100 may simultaneously transmit data on the multiple panels. Each receiving unit may be configured with a different SRS resource set. Alternatively, the terminal device 100 may be configured with a single SRS resource set. In the below disclosure, the SRS resource set either refers to the SRS resource set of a particular receiving unit of the terminal device 100, or refers to the single SRS resource set of the terminal device 100.

A network device 200 may pre-configure the higher layer parameters of the terminal device 100 and communicate the configuration to the terminal device 100 through higher layer signalling. In particular, the terminal device 100 may receive Radio Resource Control (RRC) information from a network device 200 to configure the terminal device 100. Alternatively, the configuration of the terminal device 100 may be predetermined in a protocol.

At step S403 of Figure 4, the terminal device 100 measures a path loss reference signal. In particular, the terminal device 100 receives and measures a reference signal resource configured as a path loss reference signal according to the SRS resource set of the terminal device 100. The processing unit 120 controls the communication unit 110 to receive and measure the path loss reference signal.

The resource set of the terminal device 100 includes a path loss reference signal which is one index of a reference signal resource. For example, the path loss reference signal may be one index of a CSI-RS resource or SS/PBCH block, which is transmitted by a serving network device 200a (such as a gNB) or a non-serving network device 200b, as configured for the resource set of the terminal device 100. The path loss reference signal may be a synchronization signal block (SSB) or downlink positioning reference signal (DL PRS) resource transmitted by a serving network device 200a or a non-serving network device 200b.

The path loss reference signal may be transmitted to the terminal device 100 from a serving network device 200a or from a non-serving network device 200b. The path loss reference signal may be transmitted to the terminal device 100 periodically. The path loss reference signal is measured by the terminal device 100. According to some embodiments, the measured path loss reference signal is used to calculate/estimate the path loss between the terminal device 100 and the serving network device 200a or the non-serving (neighbour) network device 200b that transmitted the path loss reference signal. The calculated/estimated path loss is used to determine the uplink transmit power for transmission of a reference signal (such as an SRS) for positioning.

At step S404 of Figure 4, the terminal device 100 determines if the path loss reference signal is received from a serving network device 200a or a non-serving network device 200b.

If the path loss reference signal is a reference signal transmitted from a serving network device 200a, it is determined by the terminal device 100 that the path loss is accurately measurable and as such the method proceeds to step S406 of Figure 4.

If the path loss reference signal is a reference signal transmitted from a non-serving network device 200b, it is determined by the terminal device 100 that the path loss reference signal may or may not be accurately measurable and thus the method proceeds to step S405 of Figure 4.

The processing unit 120 determines the source of the path loss reference signal from network device ID information that is contained within the path loss reference signal.

At step S405 of Figure 4, the terminal device 100 determines if the downlink path loss can be accurately measured based on the path loss reference signal. There are a number of methods for making this determination, as will now be described.

In a first method, the terminal device 100 measures the reference signal received power (RSRP) of the path loss reference signal and compares the measurement to a threshold. In particular, the processing unit 120 controls the communication unit 110 to measure the received power of the path loss reference signal. The processing unit 120 compares the received power of the path loss reference signal with a first threshold. If the measured received power is below the first threshold, the processing unit 120 determines that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the measured received power is not below the first threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In a second method, the terminal device 100 measures the reference signal received quality (RSRQ) of the path loss reference signal and compares the measurement to a threshold. In particular, the processing unit 120 controls the communication unit 110 to measure the received quality of the path loss reference signal. The processing unit 120 may compare the received quality of the path loss reference signal with a second threshold. If the measured received quality is below the second threshold, the processing unit 120 may determine that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the measured received quality is not below the second threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In a third method, the terminal device 100 measures the signal-to-interference noise ratio (SINR) of the path loss reference signal and compare the measurement to a threshold. In particular, the processing unit 120 controls the communication unit 110 to measure the SINR of the path loss reference signal. The processing unit 120 may compare the SINR of the path loss reference signal with a third threshold. If the measured SINR is below the third threshold, the processing unit 120 determines that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the measured SINR is not below the third threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In a fourth method, the terminal device 100 measures the received signal strength indicator (RSSI) of the path loss reference signal and compare the measurement to a threshold. In particular, the processing unit 120 controls the communication unit 110 to measure the RSSI of the path loss reference signal. The processing unit 120 compares the RSSI of the path loss reference signal with a fourth threshold. If the measured RSSI is below the fourth threshold, the processing unit 120 determines that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the measured RSSI is not below the fourth threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In a fifth method, the terminal device 100 measures the channel quality indicator (CQI) of the path loss reference signal and compares the measurement to a threshold. In particular, the processing unit 120 controls the communication unit 110 to measure the CQI of the path loss reference signal. The processing unit 120 compares the CQI of the path loss reference signal with a fifth threshold. If the measured CQI is below the fifth threshold, the processing unit 120 determines that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the measured CQI is not below the fifth threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In a sixth method, the terminal device 100 counts the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device 100 to measure and compare the number to a threshold. In particular, the processing unit 120 counts the number of instances when at least one of the first to fifth thresholds are met within a given period of time. If the number is less than a sixth threshold, the processing unit 120 determines that the path loss cannot be accurately measured by the terminal device 100 based on the path loss reference signal. If the number is not less than a sixth threshold, the processing unit 120 determines that the path loss can be accurately measured by the terminal device 100 based on the path loss reference signal.

In other words, in the sixth method, if at slot n the number of measurement chances of the path loss reference signal between slot n-N and slot n is below the sixth threshold, the processing unit 120 determines that the terminal device 100 is not able to accurately measure the downlink path loss (PL _b, f, c (q _d) ) based on the path loss reference signal. If the number of measurement chances of the path loss reference signal between slot n-N and slot n is not below the sixth threshold, the processing unit 120 determines that the terminal device 100 is able to accurately measure the downlink path loss (PL _b, f, c (q _d) ) based on the path loss reference signal.

The first to sixth thresholds may be configured by a network device 200 by transmitting configuration information to the terminal device 100. Alternatively, the thresholds may be predetermined. For example, the thresholds may each be set by a manufacturer of the terminal device 100 and pre-programmed into the terminal device 100 upon manufacture.

In a seventh method, if the terminal device 100 is not configured with a path loss reference signal parameter, the processing unit 120 determines that the path loss reference signal cannot be accurately measured by the terminal device 100 based on the path loss reference signal.

If the terminal device 100 determines at step S405 that the path loss can be accurately measured based on the path loss reference signal, the terminal device 100 is configured to follow steps S406 and S407 of Figure 4. If the terminal device 100 determines at step S405 that the path loss cannot be accurately measured based on the path loss reference signal, the terminal device 100 is configured to follow steps S408 and S409 of Figure 4.

At step S406 of Figure 4, the terminal device 100 calculates the path loss between the serving network device 200a or non-serving network device 200b and the terminal device 100. In particular, the path loss reference signal contains information stating the transmitted power of the path loss reference signal from the serving network device 200a or the non-serving network device 200b. The processing unit 120 uses the transmitted power of the path loss reference signal and the received power of the path loss reference signal by the terminal device 100 to calculate the path loss between the serving network device 200a or the non-serving network device 200b and the terminal device 100.

At step S407 of Figure 4, the terminal device 100 calculates the uplink transmission power for an SRS resource in the set q _s. In particular, the uplink transmission power (in dBm) (P _{SRS, b, f, c} (i, q _s, l) ) is calculated, based on a configuration of the terminal device 100 by information element (IE) SRS-Positioning-Config on active UL BWP b of carrier f of serving network device c, as:

where:

- P _CMAX, f, c (i) is the terminal device 100 configured maximum output power for carrier f of serving cell c in SRS transmission occasion i.

- P _{O_SRS, b, f, c} (q _s) and α _{SRS, b, f, c} (q _s) are provided by higher layer parameters p0 and alpha respectively, which are the target received power level and power adjustment factor.

- PL _b, f, c (q _d) is the downlink path loss in dB calculated by the terminal device 100 by measuring the configured path loss RS.

- M _{SRS, b, f, c} (i) is an SRS bandwidth expressed in number of resource blocks for SRS transmission.

At step S408 of Figure 4, the terminal device 100 estimates the path loss between the serving network device 200a and the terminal device 100. In some embodiments, the processing unit 120 estimates the downlink path loss using a RS resource obtained from the synchronization signal block (SSB) or SS/PBCH block that the terminal device 100 uses to obtain an MIB.

In particular, the terminal device 100 receives a SS/PBCH block from a serving network device 200a to obtain the MIB. The terminal device 100 decodes the MIB in order to receive other information transmitted on the physical downlink shared channel (PDSCH) . The serving network device 200a may transmit the SS/PBCH block periodically to the terminal device 100. The processing unit 120 may estimate the downlink path loss (PL _b, f, c (q _d) ) between the serving network device 200a and the terminal device 100 based on receiving information on the transmitted power of the SS/PBCH block and the measured received power of the SS/PBCH block.

At step S409 of Figure 4, the terminal device 100 calculates the uplink transmit power of a reference signal for positioning based on the estimated path loss that was estimated at step S408.

The calculated uplink transmit power includes a power offset. In particular, the processing unit 120 uses the estimated path loss to calculate an expected uplink transmit power and adds a power offset to the expected uplink transmit power to calculate the uplink transmit power of the SRS for positioning. The expected uplink transmit power will be referred to as the base uplink transmit power from here onwards.

The base uplink transmit power (in dBm) (P _{BASE_SRS, b, f, c} (i, q _s, l) ) is calculated, based on a configuration of the terminal device 100 by information element (IE) SRS-Positioning-Config on active UL BWP b of carrier f of serving network device c, as:

where:

- PL _b, f, c (q _d) is the downlink path loss in dB estimated by the terminal device 100 at step S408 using a RS resource obtained from the synchronization signal block (SSB) or SS/PBCH block that the terminal device 100 uses to obtain the MIB.

The power offset may be, for example, 0 dB, 1 dB, 3 dB or 5 dB added to the base uplink transmit power to calculate the uplink transmit power. The power offset may be selected from a plurality of different values stored in the terminal device 100. In particular, the plurality of different values of the power offset may be stored in the processing unit 120 of the terminal device 100.

The value of the power offset may be fixed. In this case, the value of the power offset may be set by a manufacturer of the terminal device 100 and pre-programmed into the terminal device 100 upon manufacture. Alternatively, the value of the power offset may be programmed into the terminal device 100 using an over-the-air software update.

The power offset may be a value that is configured by a network device 200 through a higher layer parameter configured by the terminal device 100 receiving configuration information from the network device 200. In this case, the value of the power offset may be variable in that it may take one of a number of different values.

The value of the power offset may be determined based on the measured path loss reference signal. For example, the power offset may be determined by providing the terminal device 100 with a mapping table, as shown below, between the power offset value and the value of the RSRP offset, where the RSRP offset is the value of the measured RSRP of the path loss reference signal minus the value of the first threshold.

In some embodiments, the processing unit 120 uses a mapping table to determine a value of the power offset based on a value of a parameter of the path loss reference signal. For example, the parameter may be the RSRP of the path loss reference signal. However, the parameter may alternatively be the RSRQ, SINR, RSSI or CQI of the path loss reference signal.

The processing unit 120 may compare threshold values L1, L2, and L3 to the offset between the measured value of the parameter and the corresponding one of the first to fifth thresholds to determine the value of the power offset. For example, if the parameter is the RSRP, the RSRP offset is the value of the measured RSRP of the path loss reference signal minus the first threshold. If the parameter is the RSRQ, the RSRQ offset is the value of the measured RSRQ of the path loss reference signal minus the second threshold. If the parameter is the SINR, the SINR offset is the value of the measured SINR of the path loss reference signal minus the third threshold. If the parameter is the RSSI, the RSSI offset is the value of the measured RSSI of the path loss reference signal minus the fourth threshold. If the parameter is the CQI, the CQI offset is the value of the measured CQI of the path loss reference signal minus the fifth threshold. If the parameter is the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device 100 to measure, the offset is the value of the measured number minus the sixth threshold.

Power offset	RSRP offset
0 dB	L1 dB ≤ RSRP offset < 0 dB
1 dB	L2 dB ≤ RSRP offset < L1 dB
2 dB	L3 dB ≤ RSRP offset < L2 dB

Table 1: Mapping table between power offset and RSRP offset

L1, L2 and L3 refer to three threshold values where L3<L2<L1<0. The values of each of L1, L2 and L3 may be fixed. Alternatively, the values of each of L1, L2 and L3 may be programmed into the terminal device 100 on manufacture or using an over-the-air software update. Although the above table states that the units of the threshold values are dB, the threshold values may be in units corresponding to the units of the measured parameter of the path loss reference signal.

From Table 1, if the measured RSRP of the path loss reference signal minus the value of the first threshold is an amount that is less than 0 dB and greater than or equal to L1 dB, the processing unit 120 determines that the power offset is a first value, which in this example is 0 dB. If the measured RSRP of the path loss reference signal minus the value of the first threshold is an amount that is less than L1 dB and greater than or equal to L2 dB, the processing unit 120 determines that the power offset is a second value, which in this example is 1 dB. If the measured RSRP of the path loss reference signal minus the value of the first threshold is an amount that is less than L2 dB and greater than or equal to L3 dB, the processing unit 120 determines that the power offset is a third value, which in this example is 2 dB.

The above mapping table is merely an example and the determined power offset and number of rows in the table as well as the value of each of the thresholds is illustrative and the number of rows and/or the values of the thresholds could instead be varied.

Generally speaking, the power offset can be selected from a set of power offset options that is stored in the terminal device 100. The set of power offset options that is stored in the terminal device 100 advantageously includes plural power offset options. One power offset option may be 0 dB. Further advantageously, the set of power offset options that is stored in the terminal device 100 includes plural non-zero power offset options. The power offset that is selected from the set advantageously is larger for lower measured signal strength or signal quality of the path loss reference signal.

At step S409 of Figure 4, the terminal device 100 calculates the uplink transmit power of an SRS for positioning (in dBm) , based on a configuration by information element (IE) SRS-Positioning-Config on active UL BWP b of carrier f of serving network device c, as:

where:

- PL _b, f, c (q _d) is the downlink path loss in dB estimated by the terminal device 100 using a RS resource obtained from the synchronization signal block (SSB) or the SS/PBCH block that the terminal device 100 uses to obtain the MIB.

- Δ is the power offset in dB.

The power offset (Δ) may be any suitable value, such as 0 dB, 1 dB, 2 dB, 3 dB or 5 dB.

At step S410 of Figure 4, the terminal device 100 transmits a reference signal for positioning at the calculated uplink transmit power. In particular, the processing unit 120 controls the communication unit 110 to transmit a sounding reference signal at the uplink transmit power calculated at either step S407 or step S409.

Figure 5 shows a flowchart operation of the terminal device 100 of Figure 2. Through the flowchart of Figure 5 discussed below, the terminal device 100 can determine if a path loss can be measured accurately based on a path loss reference signal and determine a suitable uplink transmission power for SRS for positioning.

The method of Figure 5 relates closely to the method of Figure 4. Steps S501 to S503 of Figure 5 correspond to steps S401 to S403 of Figure 4. Step S404 of Figure 4 is not included within the method of Figure 5.

The terminal device 100 following the method of Figure 5 may not determine whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200b.

The terminal device 100 following the method of Figure 5 performs the step of determining if the downlink path loss can be accurately measured based on the path loss reference signal whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200b. In particular, step S504 of Figure 5 corresponds to step S405 of Figure 4.

Steps S505 and S506 of Figure 5 correspond to steps S406 and S407 of Figure 4.

Step S507 of Figure 5 corresponds to step S408 of Figure 4.

According to some embodiments, step S508 of Figure 5 corresponds to step S409 of Figure 4. In particular, the processing unit 120 uses the path loss estimated at step S507 to calculate the base uplink transmit power (P _{BASE_SRS, b, f, c} (i, q _s, l) ) and adds the power offset (Δ) to calculate the uplink transmit power (P _{SRS, b, f, c} (i, q _s, l) ) of the reference signal for positioning. In this case, the power offset is added to the base uplink transmit power irrespective of whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200. As such, in the method of Figure 5, addition of the power offset to the base uplink transmit power to calculate the uplink transmit power is made in all circumstances where it is determined that the path loss cannot be measured accurately based on the path loss reference signal. Accordingly, the path loss is estimated using a reference signal resource that is not from the path loss reference signal and the power offset is added even when the path loss reference signal is received from a serving cell 200a.

According to other embodiments, the terminal device 100 following the method of Figure 5 determines whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200b to determine whether to add the power offset to the base uplink transmit power to calculate the uplink transmit power at step S508.

In particular, according to other embodiments, the power offset is only added to the base uplink transmission power by the processing unit 120 if the path loss reference signal is transmitted from a non-serving (neighbour) network device 200b. Here, the processing unit 120 does not add the power offset to the base uplink transmission power to calculate the uplink transmission power if the path loss reference signal is received from a serving network device 200a. The processing unit 120 determines the source of the path loss reference signal due to cell ID information contained within the path loss reference signal. In other words, the terminal device 100 following the method of Figure 5 calculates the uplink transmit power as being equal to the base uplink transmit power when a serving network 200a transmits the path loss reference signal and the terminal device determines that the path loss cannot be accurately measured based on the path loss reference signal.

Step S509 of Figure 5 corresponds to step S410 of Figure 4. In particular, at step S509, the terminal device 100 transmits a reference signal for positioning at the calculated uplink transmit power. In particular, the processing unit 120 controls the communication unit 110 to transmit a sounding reference signal at the uplink transmit power calculated at either step S506 or step S508.

The description of the steps of Figure 4 that are included in Figure 5 are not repeated here for the sake of conciseness. It will be seen that the difference between the Figures 4 and 5 flowcharts is that Figure 5 does not include a determination as to whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200b. Instead, the method of Figure 5 proceeds to determining whether the pass loss can be measured accurately irrespective of whether the path loss reference signal is received from a serving network device 200a or a non-serving network device 200. As such, in the method of Figure 5 determination of whether the pass loss can be measured accurately is made in all circumstances. Accordingly, the downlink path loss is estimated and a power offset may be added even when the path loss reference signal is received from a serving cell 200a.

It will be appreciated that the terminal device 100 following the method of either Figure 4 or 5 is able to clearly determine whether the path loss can be measured accurately based on the received path loss reference signal.

It will also be appreciated that the terminal device 100 following the method of either Figure 4 or 5 is able to transmit a reference signal for positioning which can be received by both a serving network device 200a and a non-serving network device 200b, even when the path loss reference signal is received from a non-serving network device 200b.

Figure 6 shows a flowchart of the operation of the network device 200 of Figure 3. The flowchart of Figure 6 showing the operations of the network device 200 generally corresponds to the flowcharts of Figures 4 and 5, but from the perspective of the network device 200, and corresponding comments apply. Through the flowchart of Figure 6 discussed below, the network device 200 can configure the terminal device 100 to calculate an uplink transmit power for SRS transmission for positioning.

At step S601 of Figure 6, a serving network device 200a transmits a reference signal resource to the terminal device 100. The reference signal resource may be contained within an SS/PBCH block which the terminal device 100 uses to obtain a master information block (MIB) .

At step S602 of Figure 6 (which is optional) , the serving network device 200a transmits configuration information to the terminal device 100. For example, the serving network device 200a may transmit downlink control information and/or radio resource control configuration information to configure the SRS resource set (s) of the terminal device 100.

At step S603 of Figure 6, either the serving network device 200a or a non-serving (neighbour) network device 200b transmits a path loss reference signal to the terminal device 100.

At step S604 of Figure 6, the serving network device 200a and the non-serving network device 200b receive an uplink transmission from the terminal device 100. The uplink transmission is an SRS transmission for positioning from the terminal device 100.

Both the serving network device 200a and the non-serving network device 200b may receive the SRS transmission from the terminal device 100 due to the method of the terminal device 100 described in relation to Figure 4 or 5. It will be appreciated that both the serving network device 200a and the non-serving network device 200b receiving the uplink SRS transmission permits triangulation the position of the terminal device 100.

Figure 7 shows a summary of the message flow procedure between the terminal device 100 and network device 200, according to the above discussion. Figure 7 shows the following steps:

1. The network device 200 transmits a reference signal resource to the terminal device 100.

2. The network device 200 may optionally transmit configuration information to the terminal device 100.

3. The network device 200 transmits a path loss reference signal to the terminal device 100.

4. The terminal device 100 transmits an SRS resource for positioning to the network device 200.

It will be appreciated that the network device 200 performing the third step of Figure 7 may receive the SRS resource even when the network device 200 is a non-serving (neighbour) network device 200b and when the terminal device 100 is unable to accurately measure the path loss reference signal due to the terminal device 100 following the steps as described above in relation to Figure 4 or 5.

In some embodiments, when physical uplink control channel (PUCCH) and SRS are on the same carrier, the terminal device 100 may not transmit SRS when semi-persistent and periodic SRS are configured in the same symbol (s) with PUCCH carrying only channel state information (CSI) report (s) , or only layer 1 reference signal received power (L1-RSRP) report (s) , or only layer 1 signal-to-interference noise ratio (L1-SINR) report (s) . The terminal device 100 may not transmit SRS when semi-persistent or periodic SRS is configured or aperiodic SRS is triggered to be transmitted in the same symbol (s) with PUCCH carrying hybrid automatic repeat request –acknowledge (HARQ-ACK) , link recovery request and/or scheduling request (SR) . In the case that SRS is not transmitted due to overlap with PUCCH, only the SRS symbol (s) that overlap with PUCCH symbol (s) are dropped. PUCCH may not be transmitted when aperiodic SRS is triggered to be transmitted to overlap in the same symbol with PUCCH carrying semi-persistent/periodic CSI report (s) or semi-persistent/periodic L1-RSRP report (s) only, or only L1-SINR report (s) . If an aperiodic SRS configured by the higher layer parameter [SRS-for-Positioning] collides with a scheduled physical uplink shared channel (PUSCH) or PUCCH transmission, the PUSCH or PUCCH may not be transmitted.

When a higher layer parameter spatialRelationInfo is activated/updated for a semi-persistent or aperiodic SRS resource by a medium access control (MAC) control element (CE) for a set of carrier components/bandwidth parts (CCs/BWPs) , where the applicable list of CCs is indicated by higher layer parameter [applicableCellList] , the spatialRelationInfo may be applied for the semi-persistent or aperiodic SRS resource (s) , except for the SRS resource configured by the higher layer parameter [SRS-for-positioning] , with the same SRS resource ID for all the BWPs in the indicated CCs.

When the higher layer parameter enableDefaultBeamPlForSRS is set to ‘enabled’ , and if the higher layer parameter spatialRelationInfo for the SRS resource, except for the SRS resource with the higher layer parameter usage in SRS-ResourceSet being set to 'beamManagement' or for the SRS resource with the higher layer parameter usage in SRS-ResourceSet being set to ‘nonCodebook’ with configuration of associatedCSI-RS or for the SRS resource being configured by the higher layer parameter [SRS-for-positioning] , is not configured in FR2 and if the terminal device 100 is not configured with higher layer parameter (s) pathlossReferenceRS, the terminal device 100 may transmit the target SRS resource:

- with the same spatial domain transmission filter used for the reception of the CORESET with the lowest controlResourceSetId in the active DL BWP in the CC.

- with the same spatial domain transmission filter used for the reception of the activated transmission configuration indicator (TCI) state with the lowest ID applicable to physical downlink shared channel (PDSCH) in the active DL BWP of the CC if the terminal device 100 is not configured with any CORESET in the CC.

For a terminal device 100 configured with one or more SRS resource configuration (s) , and when the higher layer parameter resourceType in SRS-Resource is set to 'semi-persistent' when the terminal device 100 receives an activation command, for an SRS resource, and when the terminal device 100 would transmit a PUCCH with HARQ-ACK information in slot n corresponding to the PDSCH carrying the activation command transmitted in slot n, the corresponding actions and the terminal device 100 determinations on SRS transmission corresponding to the configured SRS resource set may be applied starting from the first slot that is after slot

where μ is the subcarrier spacing (SCS) configuration for the PUCCH. The activation command also contains spatial relation determinations provided by a list of references to reference signal IDs, one per element of the activated SRS resource set, except for the SRS resource configured with the higher layer parameter SRS-for-Positioning. Each ID in the list refers to a reference SS/PBCH block, non-zero power (NZP) CSI-RS resource configured on serving cell indicated by Resource Serving Cell ID field in the activation command if present, same serving cell as the SRS resource set otherwise, or SRS resource configured on serving cell and uplink bandwidth part indicated by Resource Serving Cell ID field and Resource BWP ID field in the activation command if present, same serving cell and bandwidth part as the SRS resource set otherwise.

For a terminal device 100 configured with one or more SRS resource configuration (s) , and when the higher layer parameter resourceType in SRS-Resource is set to 'semi-persistent' , if an SRS resource in the activated resource set is configured with the higher layer parameter spatialRelationInfo, the terminal device 100 may determine that the ID of the reference signal in the activation command overrides the one configured in spatialRelationInfo.

In some of the embodiments, for the DL reference signal time difference (RSTD) , DL PRS-RSRP, and terminal device 100 receive-transmission (Rx-Tx) time difference measurements, the terminal device 100 may report an associated higher layer parameter Timestamp. The Timestamp can include the system frame number (SFN) and the slot number for a subcarrier spacing. If one DL PRS resource is used for the measurement, the Timestamp may include the SFN and slot number of the DL PRS resource. If one PRS resource set is used for the measurement, the Timestamp may include the SFN and slot number of the earliest DL PRS resource in the PRS resource set. These values correspond to the reference which is provided by DL-PRS-RSTDReferenceInfo.

The terminal device 100 may be expected to measure the DL PRS resource outside the active DL BWP or with a numerology different from the numerology of the active DL BWP if the measurement is made during a configured measurement gap. When not configured with a measurement gap, the terminal device 100 may only be required to measure DL PRS within the active DL BWP and with the same numerology as the active DL BWP. If the terminal device 100 is not provided with a measurement gap, the terminal device 100 may not be expected to process DL PRS resources on serving or

non-serving network devices

200a, 200b on any symbols indicated as uplink (UL) by the serving network device 200a. When the terminal device 100 is expected to measure the DL PRS resource outside the active DL BWP or with a numerology different from the numerology of the active DL BWP or on any symbols indicated as UL symbol by the serving cell, it may request a measurement gap in higher layer parameter XYZ.

The terminal device 100 may be configured to measure and report up to 8 DL PRS RSRP measurements on different DL PRS resources from the same network device 200. When the terminal device 100 reports DL PRS RSRP measurements from one DL PRS resource set, the terminal device 100 may indicate which DL PRS RSRP measurements have been performed using the same spatial domain filter for reception. When the terminal device 100 reports one DL PRS RSRP measurement, the terminal device 100 may indicate whether the DL PRS RSRP measurement has been performed using multiple different spatial domain receive filters for receiving the corresponding PRS resource.

The terminal device 100 may be indicated by the network (in that it may receive a communication from a network device 200 stating) that a DL PRS resources or a subset of DL PRS resources or a DL PRS resource set can be used as the reference for the RSTD measurement in a higher layer parameter DL-PRS-RstdReferenceInfo. The reference time indicated by the network to the terminal device 100 may also be used by the terminal device 100 to determine how to apply higher layer parameters DL-PRS-expectedRSTD and DL-PRS-expectedRSTD-uncertainty. The terminal device 100 may expect the reference time to be indicated whenever it is expected to receive the DL PRS. This reference time provided by DL-PRS-RstdReferenceInfo may include an ID, a PRS resource set ID, and optionally a single PRS resource ID or a list of PRS resource IDs. The terminal device 100 may use different DL PRS resources or a different DL PRS resource set to determine the reference time for the RSTD measurement as long as the condition that the DL PRS resources used belong to a single DL PRS resource set is met. If the terminal device 100 chooses to use a different reference time than indicated by the network, then it is expected to report the DL PRS resource ID (s) or the DL PRS resource set ID used to determine the reference.

In summary, the present disclosure provides the following methods for transmitting SRS for positioning:

- For an SRS for positioning, the terminal device 100 may be provided with a SSB or DL PRS of a serving network device 200a or a non-serving network device 200b, the terminal device 100 may be requested to determine whether a path loss can be measured accurately based on the configured path loss RS:

○ Option 1: the terminal device 100 may compare the RSRP of the path loss RS with a configured or preconfigured threshold. If the RSRP is below the threshold, the terminal device 100 may determine the path loss is not measurable.

■ Besides RSRP, the measurement metric can be RSRQ, SINR, RSSI or CQI.

○ Option 2: the terminal device 100 may use the number of available transmission instances within a given time period length. If the number of available transmission instance is less than some threshold, the terminal device 100 may determine the path loss is not measurable.

- If the path loss is not measurable, the terminal device 100 may use a fallback method to calculate the uplink transmit power for the SRS for positioning:

○ Option 1: the terminal device 100 may add one power offset (for example 3 dB) to the transmit power.

○ Option 2: the terminal device 100 may determine the uplink transmit power according to whether the path loss RS is a RS of the serving network device 200a or the non-serving network device 200b.

This provides well-defined rules for determining whether the terminal device 100 is able to measure the path loss accurately, and for transmitting SRS for positioning.

It also enables the uplink transmission power for SRS for positioning to reach the non-serving (neighbor) cell 200b even when the terminal device 100 is not able to measure the path loss accurately because the terminal device 100 uses the synchronization signal block (SSB) of the serving cell 200a to estimate the path loss. A consequence is the neighbor cell 200b can measure the SRS for positioning accurately.

In the above, estimates of path loss are calculated using measurements of signals. In some instances it is described that path loss is calculated and in some instances it is described that path loss is estimated, and these terms shall be interpreted according to the context.

Embodiments can also provide a computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any of the embodiments.

Examples of computer-readable media include both volatile and non-volatile media, removable and non-removable media, and include, but are not limited to: solid state memories; removable disks; hard disk drives; magnetic media; and optical disks. In general, the computer-readable media include any type of medium suitable for storing, encoding, or carrying a series of instructions executable by one or more computers to perform any one or more of the processes and features described herein.

It will be appreciated that the functionality of each of the components discussed can be combined in a number of ways other than those discussed in the foregoing description. For example, in some embodiments, the functionality of more than one of the discussed devices can be incorporated into a single device. In other embodiments, the functionality of at least one of the devices discussed can be split into a plurality of separate (or distributed) devices.

Conditional language such as “may” , is generally used to indicate that features/steps are used in a particular embodiment, but that alternative embodiments may include alternative features, or omit such features altogether.

Furthermore, the method steps are not limited to the particular sequences described, and it will be appreciated that these can be combined in any other appropriate sequences. In some embodiments, this may result in some method steps being performed in parallel. In addition, in some embodiments, particular method steps may also be omitted altogether.

While certain embodiments have been discussed, it will be appreciated that these are used to exemplify the overall teaching of the present disclosure, and that various modifications can be made without departing from the scope of the disclosure.

Many further variations and modifications will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only, and which are not intended to limit the scope of the disclosure, that being determined by the appended claims and their equivalents.

Claims

A method for transmitting a reference signal from a terminal device (100) , the method comprising:

receiving a path loss reference signal;

determining whether or not a value of a parameter calculated from receiving the path loss reference signal exceeds a threshold to thereby determine whether the terminal device (100) is able to accurately measure a path loss based on the received path loss reference signal;

based on the determination, calculating a transmit power for transmission of a reference signal for positioning; and

transmitting a reference signal for positioning at the calculated transmit power.
The method of claim 1, further comprising:

determining whether the path loss reference signal is received from a serving network device (200a) or a non-serving network device (200b) .
The method of claim 2, comprising determining whether or not the value of the parameter calculated from receiving the path loss reference signal exceeds the threshold in response to determining that the path loss reference signal is received from a non-serving network device (200b) .
The method of claim 3, comprising responding to determining that the path loss reference signal is from a non-serving network device (200b) and that the value of the parameter calculated from receiving the path loss reference signal does not exceed the threshold by calculating the transmit power of the reference signal for positioning by:

estimating path loss using a reference signal resource received from a serving network device (200a) ;

calculating a base transmit power based on the estimated path loss; and

adding a power offset to the preliminary transmit power to provide the calculated transmit power.
The method of claim 1, wherein calculating the transmit power of the reference signal for positioning comprises:

estimating path loss using a reference signal resource received from a serving network device (200a) ;

calculating a base transmit power based on the estimated path loss; and

adding a power offset to the base transmit power to provide the calculated transmit power.
The method of claim 4 or claim 5, wherein the value of the power offset is determined based on configuration information received by the terminal device.
The method of claim 4 or claim 5, wherein the value of the power offset is determined by the terminal device.
The method of claim 7, wherein the value of the power offset is selected from a plurality of different values stored in the terminal device.
The method of claim 7, wherein the value of the power offset is selected from a plurality of different values stored in the terminal device based on the value of the parameter calculated from receiving the path loss reference signal.
The method of claim 9, wherein the plurality of different values include a value of 0 dB.
The method of any of claims 4 to 10, comprising the terminal device transmitting the reference signal for positioning on an active uplink bandwidth part (UL BWP) b of carrier f of a serving network device c using SRS power control adjustment state with index l, and calculating the transmit power (P _{SRS, b, f, c} (i, q _s, l) ) on occasion i in an SRS resource in the set q _s using:

wherein:

P _CMAX, f, c (i) is the terminal device configured maximum output power for carrier f of serving network device c on transmission occasion i,

P _{O_SRS, b, f, c} (q _s) and α _{SRS, b, f, c} (q _s) are provided by higher layer parameter p0 and alpha respectively, which are the target received power level and power adjustment factor,

PL _b, f, c (q _d) is a downlink path loss calculated by the terminal device using a reference signal resource obtained from the synchronization signal block that the terminal device uses to obtain a master information block,

M _{SRS, b, f, c} (i) is a bandwidth expressed in number of resource blocks for transmission of the reference signal for positioning, and

Δ is the power offset.
The method of any one of claims 1 to 11, wherein the parameter is the received power of the path loss reference signal, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the received power of the path loss reference signal being below a first threshold.
The method of any one of claims 1 to 11, wherein the parameter is the received quality of the path loss reference signal, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the received quality of the path loss reference signal being below a second threshold.
The method of any one of claims 1 to 11, wherein the parameter is the signal to interference noise ratio of the path loss reference signal, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the signal to interference noise ratio of the path loss reference signal being below a third threshold.
The method of any one of claims 1 to 11, wherein the parameter is the strength indicator of the path loss reference signal, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the strength indicator of the path loss reference signal being below a fourth threshold.
The method of any one of claims 1 to 11, wherein the parameter is the channel quality indicator of the path loss reference signal, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the channel quality indicator of the path loss reference signal being below a fifth threshold.
The method of any one of claims 1 to 11, wherein the parameter is the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device to measure, the method comprising determining that the terminal device is not able to accurately measure the path loss based on the number of transmission instances of the path loss reference signal within the given time period which are available for the terminal device to measure being less than a sixth threshold.
A terminal device (100) comprising:

a communication unit (110) configured to receive a path loss reference signal; and

a processing unit (120) configured to:

determine whether or not a value of a parameter calculated from receiving the path loss reference signal exceeds a threshold to thereby determine whether the terminal device (100) is able to accurately measure a path loss based on the received path loss reference signal,

based on the determination, calculate a transmit power for transmission of a reference signal for positioning, and

control the communication unit (110) to transmit the reference signal for positioning at the calculated transmit power.
The terminal device of claim 18, wherein the processing unit is further configured to determine whether the path loss reference signal is received from a serving network device (200a) or a non-serving network device (200b) .
The terminal device of claim 19, wherein the processing unit is configured to determine whether or not the value of the parameter calculated from receiving the path loss reference signal exceeds the threshold in response to determining that the path loss reference signal is received from a non-serving network device (200b) .
The terminal device of claim 20, wherein the processing unit is configured to respond to determining that the path loss reference signal is from a non-serving network device (200b) and that the value of the parameter calculated from receiving the path loss reference signal does not exceed the threshold by calculating the transmit power of the reference signal for positioning by:

estimating the path loss using a reference signal resource received from a serving network device (200a) ;

calculating a base transmit power based on the estimated path loss; and

adding a power offset to the preliminary transmit power to provide the calculated transmit power.
The terminal device of claim 18, wherein to calculate the transmit power of the reference signal for positioning, the processing unit is configured to:

estimate the path loss using a reference signal resource received from a serving network device (200a) ;

calculate a base transmit power based on the estimated path loss; and

add a power offset to the base transmit power to provide the calculated transmit power.
The terminal device of claim 21 or claim 22, wherein the processing unit is configured to determine the value of the power offset based on configuration information received by the communication unit.
The terminal device of claim 21 or claim 22, wherein the processing unit is configured to determine the value of the power offset.
The terminal device of claim 24, wherein the processing unit is configured to select the value of the power offset from a plurality of different values stored in the terminal device.
The terminal device of claim 24, wherein the processing unit is configured to select the value of the power offset from a plurality of different values stored in the terminal device based on the value of the parameter calculated from receiving the path loss reference signal.
The terminal device of claim 26, wherein the plurality of different values include a value of 0 dB.
The terminal device of any one of claims 21 to 27, wherein the processing unit is configured to control the communication unit to transmit the reference signal for positioning on an active uplink bandwidth part (UL BWP) b of carrier f of a serving network device c using SRS power control adjustment state with index l, and calculate the transmit power (P _{SRS, b, f, c} (i, q _s, l) ) on occasion i in an SRS resource in the set q _s using:

wherein:

P _CMAX, f, c (i) is the terminal device configured maximum output power for carrier f of serving network device c on transmission occasion i,

P _{O_SRS, b, f, c} (q _s) and α _{SRS, b, f, c} (q _s) are provided by higher layer parameter p0 and alpha respectively, which are the target received power level and power adjustment factor,

PL _b, f, c (q _d) is a downlink path loss calculated by the terminal device using a reference signal resource obtained from the synchronization signal block that the terminal device uses to obtain a master information block,

M _{SRS, b, f, c} (i) is a bandwidth expressed in number of resource blocks for transmission of the reference signal for positioning, and

Δ is the power offset.
The terminal device of any one of claims 18 to 28, wherein the parameter is the received power of the path loss reference signal, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the received power of the path loss reference signal being below a first threshold.
The terminal device of any one of claims 18 to 28, wherein the parameter is the received quality of the path loss reference signal, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the received quality of the path loss reference signal being below a second threshold.
The terminal device of any one of claims 18 to 28, wherein the parameter is the signal to interference noise ratio of the path loss reference signal, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the signal to interference noise ratio of the path loss reference signal being below a third threshold.
The terminal device of any one of claims 18 to 28, wherein the parameter is the strength indicator of the path loss reference signal, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the strength indicator of the path loss reference signal being below a fourth threshold.
The terminal device of any one of claims 18 to 28, wherein the parameter is the channel quality indicator of the path loss reference signal, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the channel quality indicator of the path loss reference signal being below a fifth threshold.
The terminal device of any one of claims 18 to 28, wherein the parameter is the number of transmission instances of the path loss reference signal within a given time period which are available for the terminal device to measure, and the processing unit is configured to determine that the terminal device is not able to accurately measure the path loss based on the number of transmission instances of the path loss reference signal within the given time period which are available for the terminal device to measure being less than a sixth threshold.
A computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any one of claims 1 to 17.
A method for controlling a system comprising a terminal device (100) and a network device (200) , the method comprising the method of any one of claims 1 to 17, and further comprising receiving the reference signal for positioning by the network device (200) .
A system comprising the terminal device (100) of any one of claims 18 to 34, and a network device (200) configured to receive the reference signal for positioning.