Beam scanning on reference signal transmission for UL positioning

Abstract

A method for a base station includes sending a request for a report on beamforming capabilities to a target user equipment; receiving a report on beamforming capabilities from the target user equipment; allocating at least one positioning reference signal resource for use by the target user equipment based at least on capability information included in the report; determining a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user equipment; and sending the positioning reference signal resource allocation and the beam scanning rule to the target user equipment. A corresponding method for a user equipment includes receiving a request for a report on beamforming capabilities from a serving base station; sending a report on beamforming capabilities to the serving base station; receiving information related to at least one positioning reference signal resource and the beam scanning rule from the serving base station; and performing beam scanning for uplink positioning reference signal transmissions using the received positioning reference signal resource allocation based on the beam scanning rule.

Description

Technical Field

[0001] The present disclosure relates to a beam scanning mechanism for uplink positioning of a user equipment. More specifically, the present disclosure relates to a beam scanning mechanism by which a user equipment can inform a network whether it supports beam scanning and how many beams are required to scan in all directions so that a target gNB can allocate sufficient UL resources to the user equipment for beam scanning. Background Art

[0002] Work on local positioning support in New Radio (NR) has been completed in 3GPP. In this work, the following positioning solutions are specified for NR Rel-16:

[0003] - Downlink Time Difference of Arrival (DL-TDOA);

[0004] - Uplink Time Difference of Arrival (UL-TDOA);

[0005] - Downlink angle of departure (DL-AOD);

[0006] - Uplink angle of arrival (UL-AOA); and

[0007] -Multi-cell round trip time (multi-RTT).

[0008] Uplink Time Difference of Arrival (UL-TDOA) has been specified as one of the positioning methods in NR Rel-16. UL-TDOA uses time difference measurements based on uplink reference signals acquired by several gNBs / TRPs (Transmission and Reception Points) to determine the exact location of the User Equipment (UE). In LTE positioning, there is a logical unit called Location Measurement Unit (LMU) which can be co-located or not co-located with the base station. In NR, this terminology has changed and is instead called Transmission Measurement Function (TMF). Since some TMFs are UL-only positioning reception points (RPs), the TMF can only be used to measure UL positioning signals and perform positioning measurements such as RTOA and UL-AOA.

[0009] NR SRS has been used as a starting point for designing and analyzing UL-based positioning solutions. Beamforming on the UE side for UL transmissions is used to improve audibility in NR, especially for high frequency bands. This specification will focus on beamformed UL transmissions, which are used to support UL reception at only UL positioning reception points (RPs) in NR positioning. A sounding reference signal (SRS) is one example of a UL reference signal that can be transmitted for NR positioning; another example may be a physical random access channel (PRACH) transmission.

[0010] NR supports multi-beam transmission and reception in all NR operating bands. The NR Rel-15 beam management mechanism is mainly established for a single cell situation. The SRS signal transmitted from the UE in the SRS resource can be in omni-directional or beamforming direction. In order to support most UL-based NR positioning techniques, multiple cells are required to receive SRS from the UE.

[0011] One option to support the ability of multiple cells to receive SRS signals from a UE is based on the reciprocity principle. In this case, the UE will first measure the DL reference signals of multiple cells, such as synchronization signal blocks (SSBs), and then transmit SRS in the corresponding UL beam direction based on the received DL beam.

[0012] In detail, the UE may need to use directional spatial transmission filters to beamform the SRS or UL channel towards the intended destination. In order to facilitate correct NR SRS transmission beamforming in FR2 (frequency range 2), a reference signal for SRS spatial transmission filters is introduced in NR. Specifically, the high-level parameter spatialRelationInfo is used for the configuration of each SRS resource, which contains the ID of the reference SSB, the ID of the reference CSI-RS, or the ID of the reference SRS, together with the ID of its corresponding ULBWP. When configured with spatialRelationInfo, the UE uses the same spatial transmission filter used for the reception of the reference SSB, CSI-RS or PRS to transmit the target SRS resource.

[0013] However, in some cases, SRS spatial information is not always available. For example, for UL-only positioning reception points (RPs), it can only be used to measure UL positioning signals, and they do not transmit their own RS. In this case, the UE cannot be configured with the spatial relationship of these RPs.

[0014] A straightforward approach is to use beam scanning when the correct spatial relationship cannot be provided. However, in NR Rel-16 systems, SRS beamforming depends on the UE implementation. However, this approach cannot guarantee that the UE will perform correct beamforming and will transmit to the UL-only positioning RP. However, the beam scanning approach still has some problems:

[0015] UE may not support beamforming. Therefore, if UE uses omnidirectional antenna for SRS transmission in FR2, some neighboring cells cannot receive SRS. Therefore, hearability and positioning accuracy will be affected.

[0016] Without the gNB's instruction, the UE may not perform beam scanning or 360° scanning. For example, the UE may perform beam scanning only on the semicircle side, which is opposite to the direction of the UL-only positioning RP. In this case, these UL-only positioning RPs will not be able to receive UL SRS from the UE.

[0017] The gNB does not know the number of Tx beams that the UE needs to scan for one round. Therefore, the gNB does not know how many SRS resources should be configured for the UE. For example, if the gNB configures 3 SRS resources for the UE to perform beam scanning, but the UE needs 5 beams for one round of scanning, the UE can only scan a portion of the beam directions for SRS transmission. Then, some UL-only positioning RPs cannot receive SRS signals from the UE.

[0018] If beam scanning is completely up to the UE implementation, the gNB / UL-only positioning RP will not know how the UE performs scanning and how many resources the UE uses for scanning. For example, if 8 SRS resources are configured for scanning, but the UE only uses six for scanning, the behavior of the remaining two resources is undefined. This may cause interference or measurement issues.

[0019] In this specification, a more efficient SRS transmission mechanism is proposed to solve the above problems. Summary of the invention

[0020] In a first aspect of the present disclosure, a method includes: sending a request for a report on beamforming capabilities to a target user equipment; receiving a report on beamforming capabilities from the target user equipment; allocating at least one positioning reference signal resource for use by the target user equipment based at least on capability information included in the report; determining a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user equipment; and sending the positioning reference signal resource allocation and the beam scanning rule to the target user equipment.

[0021] In a second aspect of the present disclosure, an apparatus comprises: at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to perform the following operations: send a request for a report on beamforming capability to a target user device; receive a report on beamforming capability from the target user device; allocate at least one positioning reference signal resource for use by the target user device based at least on capability information included in the report; determine a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user device; and send the positioning reference signal resource allocation and the beam scanning rule to the target user device.

[0022] In a third aspect of the present disclosure, an apparatus includes: a component for sending a request for a report on beamforming capabilities to a target user equipment; a component for receiving a report on beamforming capabilities from the target user equipment; a component for allocating at least one positioning reference signal resource for use by the target user equipment based at least on capability information included in the report; a component for determining a beam scanning rule based on at least one positioning reference signal resource allocated to the target user equipment; and a component for sending the positioning reference signal resource allocation and the beam scanning rule to the target user equipment.

[0023] In a fourth aspect of the present disclosure, a computer program product includes a non-transitory computer-readable storage medium, which carries computer program code embodied therein for use with a computer, the computer program code including code for performing the following operations: sending a request for a report on beamforming capability to a target user device; receiving a report on beamforming capability from the target user device; allocating at least one positioning reference signal resource for use by the target user device based at least on capability information included in the report; determining a beam scanning rule based on at least one positioning reference signal resource allocated to the target user device; and sending the positioning reference signal resource allocation and the beam scanning rule to the target user device.

[0024] In a fifth aspect of the present disclosure, a method includes: receiving a request for a report on beamforming capability from a serving base station; sending a report on beamforming capability to the serving base station; receiving information related to at least one positioning reference signal resource and a beam scanning rule from the serving base station; and performing beam scanning on an uplink positioning reference signal transmission using the received positioning reference signal resource allocation based on the beam scanning rule.

[0025] In the sixth aspect of the present disclosure, an apparatus comprises: at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to perform the following operations: receive a request for a report on beamforming capability from a serving base station; send a report on beamforming capability to a serving base station; receive information related to at least one positioning reference signal resource and a beam scanning rule from the serving base station; and perform beam scanning on an uplink positioning reference signal transmission using the received positioning reference signal resource allocation based on the beam scanning rule.

[0026] In the seventh aspect of the present disclosure, an apparatus includes: a component for receiving a request for a report on beamforming capability from a serving base station; a component for sending a report on beamforming capability to a serving base station; a component for receiving information related to at least one positioning reference signal resource and a beam scanning rule from a serving base station; and a component for performing beam scanning on an uplink positioning reference signal transmission using the received positioning reference signal resource allocation based on the beam scanning rule.

[0027] In an eighth aspect of the present disclosure, a computer program product includes a non-transitory computer-readable storage medium carrying computer program code embodied therein for use with a computer, the computer program code including code for performing the following operations: receiving a request for a report on beamforming capability from a serving base station; sending a report on beamforming capability to a serving base station; receiving information related to at least one positioning reference signal resource and a beam scanning rule from the serving base station; and performing beam scanning on an uplink positioning reference signal transmission using the received positioning reference signal resource allocation based on the beam scanning rule. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The foregoing and other aspects of these teachings will become more apparent in the following detailed description when read in conjunction with the accompanying drawings.

[0029] Figure 1 Shown are simplified block diagrams of certain apparatus in which the presently disclosed subject matter may be practiced.

[0030] Figure 2 and Figure 3 An example of a New Radio (NR) architecture with a 5G Core (5GC) and NG-RAN is shown.

[0031] Figure 4 An example of dedicated beam scanning is shown.

[0032] Figure 5 An example of joint beam scanning with spatially related SRS transmissions is shown.

[0033] Figure 6 An example of beam scanning for Rx beam training at a reception point is shown.

[0034] Figure 7 The detailed process and signaling diagram of this mechanism are depicted.

[0035] Figure 8 is a flow chart illustrating a method performed by a serving base station according to the present disclosure.

[0036] Fig. 9 is a flow chart illustrating a method performed by a target user equipment according to the present disclosure. DETAILED DESCRIPTION

[0037] Figure 1 1 is a block diagram of one possible and non-limiting example in which the subject matter of the present disclosure may be practiced. A user equipment (UE) 110, a radio access network (RAN) node 170, and (multiple) network elements 190 are shown. Figure 1 In the example of FIG. 1 , a user equipment (UE) 110 wirelessly communicates with a wireless network 100. A UE is a wireless device, such as a mobile device, that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber or other optical communication device, etc. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, which includes one or both of the parts 140-1 and / or 140-2, and the module 140 may be implemented in a variety of ways. The module 140 may be implemented in hardware as the module 140-1, such as being implemented as part of the one or more processors 120. Module 140-1 may also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, one or more memories 125 and computer program code 123 may be configured to cause user equipment 110 to perform one or more of the operations described herein together with one or more processors 120. UE 110 communicates with RAN node 170 via wireless link 111.

[0038] In this example, the RAN node 170 is a base station that provides access to the wireless network 100 for wireless devices such as UE 110. The RAN node 170 may be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as a gNB or ng-eNB. A gNB is a node that provides NR user plane and control plane protocol termination towards the UE and is connected to the 5GC (e.g., (multiple) network elements 190) via an NG interface. An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination towards the UE and is connected to the 5GC via an NG interface. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and (multiple) distributed units (DU) (gNB-DU), where DU 195 is shown. Note that a DU may include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node that hosts the RRC, SDAP, and PDCP protocols of a gNB, or the RRC and PDCP protocols of an ng-eNB that controls the operation of one or more gNB-DUs. The gNB-CU terminates the F1 interface connected to the gNB-DU. The F1 interface is shown as reference numeral 198, although reference numeral 198 also shows a link between a remote element of the RAN node 170 and a centralized element of the RAN node 170, such as a link between a gNB-CU 196 and a gNB-DU 195. The gNB-DU is a logical node that hosts the RLC, MAC, and PHY layers of a gNB or en-gNB, and its operation is partially controlled by the gNB-CU. One gNB-CU supports one or more cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface 198 connected to the gNB-CU. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of the RU, but some examples in this regard may have the transceiver 160 as part of a separate RU, e.g., under the control of and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station for LTE (Long Term Evolution), or any other suitable base station or node.

[0039] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces ((multiple) N / WI / F) 161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include (multiple) processors 152, memories 155, and network interfaces 161. Note that the DU 195 may also include its own memory / memory and (multiple) processors, and / or other hardware, but these are not shown.

[0040] The RAN node 170 includes a module 150, which includes one or both of the parts 150-1 and / or 150-2, and the module 150 can be implemented in a variety of ways. The module 150 can be implemented in hardware as the module 150-1, such as being implemented as part of one or more processors 152. The module 150-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the module 150 can be implemented as a module 150-2, which is implemented as a computer program code 153 executed by one or more processors 152. For example, one or more memories 155 and the computer program code 153 are configured to cause the RAN node 170 to perform one or more of the operations described herein together with the one or more processors 152. Note that the functionality of the module 150 can be distributed, such as distributed between the DU 195 and the CU 196, or implemented solely in the DU 195.

[0041] One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more gNBs 170 may communicate using, for example, link 176. Link 176 may be wired or wireless or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interfaces for other standards.

[0042] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical fiber or other optical communication device, wireless channel, etc. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for a gNB implementation for 5G, where other elements of the RAN node 170 may be physically located at a different location from the RRH / DU, and the one or more buses 157 may be partially implemented as, for example, fiber optic cables or other suitable network connections for connecting other elements of the RAN node 170 (e.g., central unit (CU), gNB-CU) to the RRH / DU 195. Reference numeral 198 also indicates those suitable network link(s).

[0043] Note that the descriptions herein indicate that a "cell" performs a function, but it should be clear that the equipment that forms the cell performs the function. A cell forms part of a base station. That is, each base station can have multiple cells. For example, a single carrier frequency and associated bandwidth can have three cells, each covering one-third of a 360° area, so that the coverage area of ​​a single base station covers an approximate ellipse or circle. In addition, each cell can correspond to a single carrier and a base station can use multiple carriers. So if there are 3 120° cells per carrier and there are 2 carriers, the base station has a total of six cells.

[0044] The wireless network 100 may include one or more network elements 190, which may include core network functions and provide connectivity to other networks such as telephone networks and / or data communication networks (e.g., the Internet) via one or more links 181. Such core network functions for 5G may include access and mobility management functions (AMFs) and / or user plane functions (UPFs) and / or session management functions (SMFs). Such core network functions for LTE may include MME (mobility management entity) / SGW (serving gateway) functions. These are merely exemplary functions that may be supported by (multiple) network elements 190, and note that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via a link 131. The link 131 may be implemented as, for example, an NG interface for 5G, or an S1 interface for LTE, or other suitable interfaces for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces ((multiple) N / WI / F) 180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, together with the one or more processors 175, cause the network element 190 to perform one or more operations.

[0045] The wireless network 100 can implement network virtualization, which is a process of combining hardware and software network resources and network functions into a single software-based management entity (virtual network). Network virtualization involves platform virtualization, which is usually used in conjunction with resource virtualization. Network virtualization is divided into external network virtualization or internal network virtualization. External network virtualization combines many networks or network parts into virtual units, while internal network virtualization provides network-like functions for software containers on a single system. Note that the virtualized entities generated by network virtualization are still implemented using hardware such as processors 152 or 175 and memories 155 and 171 to some extent, and such virtualized entities also produce technical effects.

[0046] Computer readable memories 125, 155, and 171 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Computer readable memories 125, 155, and 171 may be means for performing storage functions. Processors 120, 152, and 175 may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Processors 120, 152, and 175 may be means for performing functions, such as controlling UE 110, RAN node 170, and other functions described herein.

[0047] In general, various embodiments of user device 110 may include, but are not limited to, a cellular telephone with wireless communication capabilities (such as a smart phone, a tablet computer, a personal digital assistant (PDA)), a portable computer with wireless communication capabilities, an image capture device with wireless communication capabilities (such as a digital camera), a gaming device with wireless communication capabilities, a music storage and playback device with wireless communication capabilities, an Internet device allowing wireless Internet access and browsing, a tablet computer with wireless communication capabilities, and a combination of portable units or terminals incorporating such functionality.

[0048] Figure 2 and Figure 3 An example of a new radio (NR) architecture with a 5G core (5GC) and NG-RAN is shown. The base stations gNB are coupled to the 5GC via an interface with the core NG, and the gNBs are coupled to each other via an inter-base station interface Xn.

[0049] In UL-TDOA (uplink time difference of arrival) as a type of user equipment positioning, multiple cells, gNBs, and transmission and reception points must "listen" to the sounding reference signal from the user equipment and use the sounding reference signal to determine the location of the user equipment. To obtain better hearability, reciprocity can be used. With reciprocity, the cell transmits a positioning reference signal to the user equipment, and the user equipment then transmits the sounding reference signal back to the cell in the corresponding uplink direction.

[0050] Some cells or reception points may be uplink-only and therefore unable to transmit positioning reference signals to user equipment. Therefore, the user equipment cannot send sounding reference signals back to these cells via reciprocity to enable positioning. One method for ensuring that such cells receive sounding reference signals from user equipment is beam scanning of sounding reference signals at the user equipment. However, user equipment may vary from implementation to implementation and have different beam scanning capabilities. Without knowing the beam scanning capabilities of individual user equipment, a cell cannot reliably receive beam scanning sounding reference signals from a user equipment.

[0051] Therefore, there is a need for an uplink positioning scheme that will work more reliably across different types of user equipment and different types of cells.

[0052] The present disclosure proposes a method, which collects the beam scanning capability of a user equipment, generates a beam scanning rule based on the beam scanning capability of the user equipment, and causes the user equipment to operate according to the beam scanning rule.

[0053] In the following discussion, reference is often made to the use of a sounding reference signal (SRS), which is an example of a positioning reference signal (PRS). It should be understood that other types of positioning reference signals may be used in the practice of the methods disclosed herein.

[0054] One feature of the present disclosure relates to providing a network-indicated Tx beam scanning mechanism to facilitate SRS reception in UL-only positioning RPs. Accordingly, the UE can inform the network whether it supports Tx beam scanning and how many beams are required to scan all directions (i.e., 360°) if beam scanning is supported. With such information, the gNB can allocate sufficient SRS resources for the UE to perform beam scanning. At the same time, the gNB will instruct the UE how to beam scan the SRS transmission in the configured SRS resources.

[0055] The proposed mechanisms include the following:

[0056] Ability Collection:

[0057] The gNB shall collect beamforming capabilities from the target UE, which shall include at least the following information:

[0058] Whether the UE supports Tx beam scanning;

[0059] The number of Tx beams required for full scan - "Full scan" or "comprehensive" refers to beamforming transmissions such that the set of beams in the scan covers a 360° plane in the spatial domain;

[0060] The number of SRS resources required for a full scan;

[0061] Information on supported beamwidths, i.e., maximum and minimum beamwidths; and

[0062] Optionally, information about the SRS beam transmission direction.

[0063] Beam scanning rule determination based on the collected capability information:

[0064] The gNB will formulate beam scanning rules to ensure that the UE can scan the correct direction, including three scanning modes:

[0065] Mode 1: Use full beam scanning in FR1 or when the UE does not support beam scanning.

[0066] Antenna;

[0067] Mode 2: uses 360° beam scanning in FR2;

[0068] - Option 1: Dedicated beam scanning SRS resources; and

[0069] - Option 2: Scanning SRS resources using joint beams with spatially related SRS; and

[0070] Mode 3: Scanning in partial beam direction.

[0071] Beam scanning rule indication:

[0072] The gNB indicates the beam scanning rules to the target UE, e.g. via RRC signalling; and

[0073] • The UE indicates whether it has completed beam scanning, e.g., by RRC signaling.

[0074] The proposed mechanism will now be described in more detail through various embodiments.

[0075] Without knowing the beam scanning rules and the specific SRS configuration, the UE will not be able to perform beam scanning in a correct way.

[0076] To determine the SRS resources and beam scanning rules, the gNB will request the UE to report the UE capabilities. Based on the reported UE capabilities, the gNB will allocate SRS resources for beam scanning and provide a scanning mode to tell the UE how to perform beam scanning.

[0077] Example embodiments of UE capability collection:

[0078] In LTE, UE capability information is an RRC message sent by the UE to the network. The network first sends a UECapabilityEnquiry message to the UE, and the UE responds with a UECapabilityInformation, as shown in Table 1 below, which gives an example of a UE capability information query. Currently, we can reuse the same process in the LTE system. However, in the currently proposed mechanism, we should introduce additional UE capability information in the UECapabilityInformation and UECapabilityEnquiry messages, as shown in Table 2.

[0079] Table 1

[0080] direction information Notes UE←NW UECapabilityEnquiry The network requests the UE to send capability information UE→NW UECapabilityInformation UE reports this information to NW upon request

[0081] Table 2

[0082]

[0083] A baseline beam scanning capability parameter set may be used. For example, if a given UE supports the UL AOA method in FR2, it may have a baseline set of Tx beam scanning capabilities. This may further minimize the overhead of capability signaling and simplify implementation.

[0084] Example embodiment of SRS resource allocation:

[0085] Based on the reported beamforming capability information, the serving gNB will configure SRS resources for the target UE.

[0086] In FR1 or in case the UE cannot support beam scanning even in FR2, one SRS resource will be configured to the UE for the omni-directional antenna.

[0087] Here, if the UE supports beam scanning for FR2, we consider two options for resource configuration:

[0088] Option 1: Dedicated SRS resource for beam scanning:

[0089] The SRS resources used for beam scanning can be separated from the SRS resources that have been configured with spatial relationships. The SRS resources used for beam scanning will not take into account the resources of the SRS with spatial relationships.

[0090] In this case, SRS resources have been allocated according to the number of Tx beams / the number of SRS resources reported by the UE for completing 360° scanning on the UE side.

[0091] For example, if the UE needs six Tx beams to scan all directions, the gNB will allocate six SRS resources to the UE. Figure 4As shown, Figure 4 An example of dedicated beam scanning is shown, where UE 402 transmits SRS on six different beam directions SRS#1 to SRS#6 in six SRS resources configured by the serving gNB.

[0092] Option 2: Resource sharing with spatially correlated SRS transmission:

[0093] In some cases, the UL positioning RP is located near a neighboring gNB; therefore, the RP can receive normal SRS for the neighboring gNB. Here, we can combine such beam scanning with normal spatial relation SRS transmission. Therefore, the SRS resources for beam scanning will be shared with the spatial relation SRS resources. The serving gNB configures both the reference DL RS for spatial relation and the beam scanning resources in the same SRS resource set.

[0094] First, the serving gNB needs to know some additional information in order to configure the correct number of SRS resources for full beam scanning.

[0095] In one embodiment, the UE may report in spatialRelationInfo the Rx beam that the UE uses to receive RS. Before SRS resource configuration, the UE may report the Rx beam ID of its corresponding RSRP / RSRQ value measured on each configured DL RS resource, and / or the Rx beam ID of the preferred DL RS resource, such as the resource with the highest RSRP / RSRQ. Based on this information, the serving gNB can know how many SRS resources are required to complete a scan. For example, if the UE configures spatialRelationInfo for gNB A and B, it can actually use the same Rx beam for both. In this case, even if 2 out of the six gNBs are configured with spatialRelationInfo, it still needs five resources to complete the scan.

[0096] In another embodiment, the UE may report receiver beam information (e.g., receiver beam identification and / or the number of beams required to scan the remaining beams not covered by the spatial relation SRS). This information may be used in the update phase of the SRS resource reconfiguration. For example, at the beginning, the serving gNB allocates six resources for the UE to complete a full scan. Then, if the UE finds that the spatial relation SRS transmission already covers three beam directions, only three SRS resources will be required to scan the remaining beams. The UE then sends the request information to the serving gNB along with the number of SRS resources used only to scan the remaining beams for an SRS configuration update.

[0097] Then, the SRS resources for beam scanning may be configured according to the number of remaining beam directions not covered by the SRS resources configured with the spatial relation RS. Alternatively, the SRS resources for beam scanning may be configured in spatialRelationInfo based on the Rx beam used by the UE to receive the RS.

[0098] For example, if the UE needs six Tx beams to scan all directions, and the gNB has configured 3 Tx beam directions with spatial relation SRS, the gNB will only configure the remaining 3 SRS resources for beam scanning. Figure 5 As shown, Figure 5 An example of joint beam scanning with spatial relation SRS transmission is shown, where SRS#1 504, SRS#2 506, and SRS#3 508 have already configured spatial relation SRS towards the normal SRS transmission of the neighboring gNB. Therefore, the serving gNB only needs to configure the remaining three SRS resources SRS#4 510, SRS#5 512, and SRS#6 514 for beam scanning.

[0099] Example embodiment of beam scanning rule design:

[0100] The gNB will instruct the UE how to perform beam scanning based on the allocated SRS resources. For example, when the UE receives six SRS resources, the UE should know whether these six SRS resources can only be used for beam scanning, or whether beam scanning should share these six resources with spatial relation SRS transmission.

[0101] Here, the following beam scanning patterns are described:

[0102] Mode 1: Omnidirectional antenna transmission

[0103] In current systems, in FR1, UEs can use omnidirectional or directional antennas, depending on UE implementation. In this disclosure, omnidirectional antennas in FR1 should be mandatory for multi-cell reception. And, if the UE cannot support beam scanning, omnidirectional antennas should also be used.

[0104] Mode 2: Use 360° scanning

[0105] In FR2, if the UE supports beam scanning, it should be mandatory to perform beam scanning. Based on different resource allocation methods, different scanning methods should be used on the UE side.

[0106] Option 1: Dedicated beam scanning

[0107] In this option, the UE shall scan all beam directions. Figure 4As shown, UE 402 transmits SRSs to six different beam directions, SRS#1 404, SRS#2 406, SRS#3 408, SRS#4 410, SRS#5 412, and SRS#6 414, to cover all directions.

[0108] Option 2: Joint beam scanning with spatially correlated SRS transmissions

[0109] In this option, the UE shall only scan the remaining beam directions, excluding the beam directions that have been configured with spatial relationships. Figure 5 As shown, UE 502 only needs to perform beam scanning in three different directions, namely, SRS#4 510, SRS#5 512, and SRS#6 514. In addition, UE 502 transmits spatial relationship SRS in the other three directions, namely, SRS#1 504, SRS#2 506, and SRS#3 508.

[0110] Mode 3: Scanning only in some desired directions for some specific purposes

[0111] In some cases, the SRS may scan in the coarse direction of other gNBs that the serving gNB also considers to be in the direction of the UL-only positioning RP. For example, for some purposes, such as Rx beam training at the reception point RP, the gNB may request the UE to perform Tx beam scanning. Figure 6 An example of such a scenario is shown where the RP 604 is located on one side of the anchor gNB 606 with an angular offset.

[0112] exist Figure 6 In this case, the UE 602 only needs to scan an angle offset from one anchor node 606, where the anchor node can be one of the neighboring gNBs or the serving gNB. In this case, the serving gNB also needs to tell the UE 602 how to scan around the anchor node 606, for example, the scanning direction, such as clockwise or counterclockwise, or left or right, etc. Here, the UE 602 can adjust the beam width based on the instructions of the serving gNB, or adjust itself based on the UE capabilities, such as the maximum beam width and minimum beam width, angle offset, and allocated SRS resources. Figure 6 As shown, the UE 602 transmits SRS in two directions SRS#1 608 and SRS#2 610 to the right of the anchor beam 612 to facilitate Rx beam training at the reception point RP 604.

[0113] Example embodiments of beam scanning rule indications:

[0114] Here, we will describe how to indicate the beam scanning mode. This includes two parts: mode indication and some additional parameters for each mode.

[0115] (1) Mode indication:

[0116] In one embodiment, two bits (b1, b2) for indicating the scanning mode are introduced as follows:

[0117] b1b2=00 indicates mode 1 (omnidirectional antenna transmission);

[0118] b1b2=01 indicates mode 2 (360° beam scanning option 1);

[0119] b1b2=10 indicates mode 2 (360° beam scanning option 2); and

[0120] b1b2=11 indicates mode 3 (scanning partial beam directions).

[0121] In another embodiment, new terms "omni-directional transmission", "360° beam scanning" and "partial beam scanning" may be introduced. When the term "360° beam scanning" is enabled, a new bit signaling is introduced to indicate which option of 360° beam scanning is used for this scanning mode.

[0122] (2) Additional parameters for Mode 2:

[0123] For mode 2, in addition to the beam scanning mode, additional parameters should be indicated to the UE. There are two alternatives for this indication, as follows:

[0124] Implicit instructions:

[0125] The gNB can implicitly indicate to the UE to perform beam scanning based on the configured SRS resources. For example, if the gNB configures six SRS resources for dedicated beam scanning, as in Option 1, it means that the UE should use six Tx beams to complete 360° scanning.

[0126] Explicit Instructions

[0127] The gNB may also indicate some additional parameters to facilitate UE beam scanning. For example, the parameters should at least include beam width, radiation angle, or relative angle offset between two beams, etc. Table 3 shows the additional parameters for mode 2.

[0128] Table 3

[0129] element definition Beam width Specifies the beam width of the beam Radiation Angle Specify the radiation angle of the beam Angle offset Specifies the relative angular offset between the two beams

[0130] Both indication methods have advantages and disadvantages. They can be used alone or in combination. The implicit indication method has low signaling overhead. However, the explicit indication method is more flexible and can flexibly adjust the beam scanning mode.

[0131] (3) Additional parameters for mode 3:

[0132] For sweep mode 3, in addition to the beam sweep mode, additional parameters shall be indicated to the UE. For example, the parameters shall include the SSB index of the anchor node, the angle offset from the anchor node, the sweep direction (such as right or left, clockwise or counterclockwise), the number of Tx beams from the anchor node to the right, and the number of Tx beams from the anchor node to the left. Table 4 shows the additional parameters for mode 3.

[0133] In addition, the signaling of the beam scanning mode (b1b2) and the additional parameters for scanning mode 3 in Table 4 can be sent from the gNB to the UE via a radio resource control (RRC) message.

[0134] Based on this indication, when the UE receives SRS resource configuration from the serving gNB, the UE can know how to perform beam scanning.

[0135] Table 4

[0136]

[0137] Example embodiment of the positioning process:

[0138] Figure 7 The detailed process of this mechanism is shown, including the following steps and signaling flow:

[0139] Step 1: The serving gNB will first request the target UE to report 702 the beamforming capability information via RRC signaling, as shown in Table 1.

[0140] Step 2: The UE reports 704 some or all of the capability information in Table 2 to the serving gNB using the RRC signaling in Table 1. For example, the UE supports up to six Tx beams. Therefore, the UE reports the number of Tx beams as a value of six (6) to the serving gNB.

[0141] Step 3: Based on the beamforming capability information reported from step 2, the gNB will configure 706 SRS resources for the target UE. Detailed SRS resource configuration can be seen in the “Exemplary embodiment of SRS resource allocation” above. For example, the serving gNB can allocate six (6) SRS resources for dedicated beam scanning.

[0142] Step 4: Based on the SRS resources allocated from step 3, the gNB will formulate 708 beam scanning rules to ensure that the UE can perform correct scanning based on the allocated SRS resources. The detailed beam scanning rules can be seen in the "Exemplary embodiment of beam scanning rule design" above. For example, the serving gNB can select option 1 of scanning mode 2 for the UE.

[0143] Step 5: The serving gNB shall also provide 710 SRS resources and beam scanning rules to the UE via RRC signaling. Detailed indication signaling can be seen in the above "Exemplary embodiment of beam rule indication". For example, if the gNB selects option 1 of mode 2, the serving gNB will send bits b1b2=01 to the UE via RRC signaling.

[0144] Step 6: Based on the beam scanning rule, the target UE will perform 712Tx beam scanning for UL SRS transmission in the allocated SRS resources. For example, based on the signaling b1b2=01 indicated from the serving gNB, the UE may know that it should use six SRS resources to complete a 360° scan, such as Figure 4 shown.

[0145] advantage:

[0146] This mechanism can ensure that the UE can perform correct SRS beam scanning and transmit SRS to the UL-only positioning RP. This is critical to ensure that the RP can measure the SRS signal. Without the current mechanism, the network may not be able to correctly configure the SRS transmission for beamforming. In turn, this mechanism improves the overall positioning accuracy and minimizes resource overhead.

[0147] Figure 8 is a flow chart illustrating a method performed by a serving base station according to the present disclosure. In block 802, the base station sends a request for a report on beamforming capabilities to a target user equipment. In block 804, the base station receives a report on beamforming capabilities from the target user equipment. In block 806, the base station allocates at least one positioning reference signal resource for use by the target user equipment based at least on the capability information included in the report. In step 808, the base station determines a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user equipment. And, in block 810, the base station sends the positioning reference signal resource allocation and the beam scanning rule to the target user equipment.

[0148] Fig. 9 is a flow chart illustrating a method performed by a target user equipment according to the present disclosure. In block 902, the user equipment receives a request for a report on beamforming capabilities from a serving base station. In block 904, the user equipment sends a report on beamforming capabilities to the serving base station. In block 906, the user equipment receives information related to at least one positioning reference signal resource and a beam scanning rule from the serving base station. And, in block 908, the user equipment performs beam scanning for uplink positioning reference signal transmissions using the received positioning reference signal resource allocation based on the beam scanning rule.

[0149] In general, various exemplary embodiments may be implemented by hardware or dedicated circuits, software, logic or any combination thereof. For example, some aspects may be implemented by hardware, while other aspects may be implemented by firmware or software, which may be executed by a controller, microprocessor or other computing device, but exemplary embodiments are not limited thereto.

[0150] Although various aspects of the exemplary embodiments of the present disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that, as non-limiting examples, these blocks, devices, systems, techniques, or methods described herein may be implemented by hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof.

[0151] It should therefore be understood that at least some aspects of the exemplary embodiments of the present disclosure may be practiced through various components, such as integrated circuit chips and modules, and that the exemplary embodiments of the present disclosure may be implemented in a device implemented as an integrated circuit. One or more integrated circuits may include circuitry, and possibly firmware, for implementing at least one or more of one or more data processors, one or more digital signal processors, baseband circuitry, and radio frequency circuitry, which are configurable to operate according to the exemplary embodiments of the present disclosure.

[0152] Various modifications and adaptations to the foregoing exemplary embodiments of the present disclosure will be apparent to those skilled in the relevant art in view of the foregoing description when read in conjunction with the accompanying drawings. For example, while the exemplary embodiments have been described in the context of improvements to 5G NR systems, it should be understood that the exemplary embodiments of the present disclosure are not limited to use with only this particular type of wireless communication system. The exemplary embodiments of the present disclosure presented herein are illustrative and are not exhaustive or otherwise intended to limit the scope of the exemplary embodiments.

[0153] The following abbreviations may be used in the preceding discussion:

[0154] AOA: Angle of Arrival

[0155] AOD: Angle of departure

[0156] BWP: Bandwidth Part

[0157] CSI: Channel State Information

[0158] CU: Centralized Unit

[0159] DL: Downlink

[0160] DU: Distributed Unit

[0161] eNB: eNodeB (4G base station)

[0162] FR: Frequency range

[0163] FR1: Frequency Range 1

[0164] FR2: Frequency Range 2

[0165] GHz: Gigahertz

[0166] gNB: gNodeB (5G base station)

[0167] gNB-CU: gNB Centralized Unit

[0168] gNB-DU: gNB distributed unit

[0169] ID: Identifier

[0170] LMF: Location Management Function

[0171] LMU: Position Measurement Unit

[0172] LPP: LTE Positioning Protocol

[0173] LTE: Long Term Evolution

[0174] NR: New Radio (5G)

[0175] PRS: Positioning Reference Signal

[0176] RF: Radio Frequency

[0177] RP: Receiving Point

[0178] RRC: Radio Resource Control

[0179] RS: Reference signal

[0180] RSRP: Reference Signal Received Power

[0181] RSRQ: Reference Signal Received Quality

[0182] RSTD: Reference Signal Time Difference

[0183] RTOA: Receive Time of Arrival

[0184] RTT: Round Trip Time

[0185] Rx: Receiver

[0186] SI: Research Projects

[0187] SIB: System Information Block

[0188] SRS: Sounding Reference Signal

[0189] SSB: Synchronization Signal Block

[0190] TDOA: Time Difference of Arrival

[0191] TMF: Transmission Measurement Function

[0192] TOA: Time of Arrival

[0193] TRP: Transmission and Reception Point

[0194] Tx: Transmitter

[0195] UE: User Equipment

[0196] UL: Uplink

[0197] UL-TDOA: Uplink Time Difference of Arrival

[0198] WI: Work Item

[0199] 3GPP: Third Generation Partnership Project

[0200] 5G: Fifth Generation

[0201] 5GC: 5G Core

[0202] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the disclosed embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "comprise" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0203] The description of the present exemplary embodiments is presented for the purpose of illustration and description and is not intended to be exhaustive or limited to the embodiments of the disclosed form. Many modifications and variations will be clear to those of ordinary skill in the art without departing from the scope and spirit of the present disclosure. The embodiments are selected and described in order to best explain the principles and practical applications of the present disclosure and to enable others of ordinary skill in the art to understand the disclosure of various embodiments with various modifications suitable for the intended specific use.

[0204] Various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings. However, any and all modifications of the teachings of this disclosure will still fall within the scope of its non-limiting embodiments.

[0205] Although described in the context of specific embodiments, it will be apparent to those skilled in the art that many modifications and various changes may be made to these teachings. Thus, although examples have been specifically shown and described with respect to one or more disclosed embodiments, it will be appreciated by those skilled in the art that certain modifications or changes may be made therein without departing from the scope of the present disclosure set forth above or the scope of the following claims.

Claims

1. A method for communication, comprising: sending a request for a report on beamforming capabilities to a target user equipment; receiving the report on the beamforming capability from the target user equipment; Based at least on the information of the beamforming capability included in the report, at least one positioning reference signal resource is allocated for use by the target user equipment, wherein the allocation of the at least one positioning reference signal resource comprises: one or more positioning reference signal resources for beam scanning, and one or more positioning reference signal resources with configured spatial relationships, wherein the one or more positioning reference signal resources for beam scanning are allocated according to the number of beam directions not covered by the one or more positioning reference signal resources with configured spatial relationships; Determining a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user equipment; and The positioning reference signal resource allocation and the beam scanning rule are sent to the target user equipment.

2. The method of claim 1 , wherein the report on beamforming capabilities comprises one or more of: Whether the user equipment supports beam scanning; The number of beams required for a full scan; The number of positioning reference signal resources required for a full scan; and Information about the maximum supported beamwidth and the minimum supported beamwidth.

3. The method of claim 1 , wherein the allocating of the at least one positioning reference signal resource comprises: One or more dedicated positioning reference signal resources for beam scanning.

4. The method according to claim 1, wherein the beam scanning rule causes the target user equipment to scan according to one of the following three modes: Mode 1, in which when the target user equipment does not support beam scanning, an omnidirectional antenna is used for transmission; Mode 2, in which when the target user equipment supports beam scanning, integrated beam scanning is used; and Mode 3, in which partial beam scanning is used when the target user equipment supports beam scanning.

5. A device for communication, comprising: means for sending a request for a report on beamforming capabilities to a target user equipment; means for receiving said report on said beamforming capability from said target user equipment; A means for allocating at least one positioning reference signal resource for use by the target user equipment based at least on the information of the beamforming capability included in the report, wherein the allocation of the at least one positioning reference signal resource comprises: one or more positioning reference signal resources for beam scanning, and one or more positioning reference signal resources with a configured spatial relationship, wherein the one or more positioning reference signal resources for beam scanning are allocated according to the number of beam directions not covered by the one or more positioning reference signal resources with the configured spatial relationship; means for determining a beam scanning rule based on the at least one positioning reference signal resource allocated to the target user equipment; and A component for sending the positioning reference signal resource allocation and the beam scanning rule to the target user equipment.

6. The apparatus of claim 5, wherein the report on beamforming capabilities comprises one or more of: Whether the user equipment supports beam scanning; The number of beams required for a full scan; The number of positioning reference signal resources required for a full scan; and Information about the maximum supported beamwidth and the minimum supported beamwidth.

7. The apparatus of claim 5, wherein the allocation of the at least one positioning reference signal resource comprises: One or more dedicated positioning reference signal resources for beam scanning.

8. The apparatus according to claim 5, wherein the beam scanning rule causes the target user equipment to scan according to one of the following three modes: Mode 1, in which when the target user equipment does not support beam scanning, an omnidirectional antenna is used for transmission; Mode 2, in which when the target user equipment supports beam scanning, integrated beam scanning is used; and Mode 3, in which partial beam scanning is used when the target user equipment supports beam scanning.

9. An apparatus for communication, comprising: means for receiving a request for a report on beamforming capabilities from a serving base station; means for sending said report regarding said beamforming capability to said serving base station; A component for receiving information related to at least one positioning reference signal resource and a beam scanning rule from the serving base station, wherein the at least one positioning reference signal resource comprises: one or more positioning reference signal resources for beam scanning, and one or more positioning reference signal resources with configured spatial relationships, wherein the one or more positioning reference signal resources for beam scanning are configured according to the number of beam directions not covered by the one or more positioning reference signal resources with configured spatial relationships; as well as Means for performing beam scanning for uplink positioning reference signal transmission using the received positioning reference signal resource allocation based on the beam scanning rule.

10. The apparatus of claim 9, wherein the report on beamforming capabilities comprises one or more of: Whether beam scanning is supported; The number of beams required for a full scan; The number of positioning reference signal resources required for a full scan; and Information about the maximum supported beamwidth and the minimum supported beamwidth.

11. The apparatus according to claim 9, wherein the at least one positioning reference signal resource comprises: One or more dedicated positioning reference signal resources for beam scanning.

12. The apparatus of claim 9, wherein the beam scanning rule enables scanning according to one of the following three modes: Mode 1, in which omnidirectional antenna transmission is used when beam scanning is not supported; Mode 2, in which integrated beam scanning is used when beam scanning is supported; and Mode 3, in which partial beam scanning is used when beam scanning is supported.

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