UL SRS power control under multi-TRP operation for C-JT

Abstract

A method, computer program and apparatus are provided for causing an apparatus to at least: receive a sounding reference signal configuration comprising one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining a plurality of pathloss reference points from one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers; determining a transmit power level of sounding reference signal resource transmission based on the joint metric of the plurality of pathloss reference points to probe channels for the plurality of transmission and reception points; determining a set of transmission and reception points of the plurality of transmission and reception points based on the determined transmit power level; and transmitting uplink data or reference signals or control information from the user equipment to a plurality of transmission and reception points within the set based on the determined transmit power level using one or more sounding reference signal resources.

Description

Technical Field

[0001] The exemplary and non-limiting example embodiments relate generally to communications, and more particularly, to UL SRS power control under multi-TRP operation for C-JT. Background Art

[0002] It is known to implement multiple transmit and receive architectures in communication networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The above-described aspects and other features are explained in the following description in conjunction with the accompanying drawings.

[0004] Figure 1 is a block diagram of one possible non-limiting system in which example embodiments may be practiced;

[0005] Figure 2A An example multi-TRP system setup is shown;

[0006] Figure 2B The range of path loss / RX power tolerance is shown;

[0007] Figure 3A A strategy based on minimizing UE power usage is shown;

[0008] Figure 3B A strategy based on limited maximum UE power is shown;

[0009] Figure 3C The RMS-based power control strategy is shown;

[0010] Figure 4 is an example apparatus configured to implement the examples described herein;

[0011] Figure 5 is an example method performed using a user device to implement the examples described herein;

[0012] Figure 6 is an example method performed using a network node to implement the examples described herein. DETAILED DESCRIPTION

[0013] Go to Figure 1 , which shows a block diagram of one possible non-limiting example in which the examples may be practiced. A user equipment (UE) 110, a radio access network (RAN) node 170, and a network element 190 are shown. Figure 1In the example of , user equipment (UE) 110 wirelessly communicates with wireless network 100. UE is a wireless device that can access wireless network 100. 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. One or more buses 127 can be address, data or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fiber or other optical communication equipment, etc. One or more transceivers 130 are connected to one or more antennas 128. One or more memories 125 include computer program code 123. UE 110 includes module 140, which includes one or both of parts 140-1 and / or 140-2, which can be implemented in a variety of ways. Module 140 can be implemented as module 140-1 in hardware, for example, as part of one or more processors 120. Module 140-1 may also be implemented as an integrated circuit, or implemented 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, together with one or more processors 120, cause user equipment 110 to perform one or more operations described herein. UE 110 communicates with RAN node 170 via wireless link 111.

[0014] In this example, the RAN node 170 is a base station that provides access to the wireless network 100 for wireless devices such as the UE 110. The RAN node 170 may be, for example, a base station for 5G (also referred to 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., network element 190) via an NG interface (e.g., connection 131). An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to the UE and is connected to the 5GC via an NG interface (e.g., connection 131). The NG-RAN node may include multiple gNBs, and the gNB may also include a central unit (CU) (gNB-CU) 196 and a distributed unit (DU) (gNB-DU), of which DU 195 is shown. Note that the DU 195 may include or be coupled to a radio unit (RU) and control the RU. The gNB-CU 196 is a logical node that hosts the radio resource control (RRC), SDAP and PDCP protocols of the gNB or the RRC and PDCP protocols of the en-gNB, which control the operation of one or more gNB-DUs. The gNB-CU 196 terminates the F1 interface connected to the gNB-DU 195. The F1 interface is shown as reference 198, although reference 198 also shows a link between a remote unit of the RAN node 170 and a centralized unit of the RAN node 170, such as a link between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and its operation is controlled in part by the gNB-CU 196. One gNB-CU 196 supports one or more cells. One cell can be supported by one gNB-DU 195, or one cell can be supported / shared by multiple DUs under RAN sharing. The gNB-DU 195 terminates the F1 interface 198 connected to the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, for example as part of the RU, but some examples may include the transceiver 160 as part of a separate RU, for example under the control of the DU 195 and connected to the DU 195. The RAN node 170 may also be an eNB (evolved Node B) base station for LTE (Long Term Evolution), or any other suitable base station or node.

[0015] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (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 the processor 152, the memory 155, and the network interface 161. Note that the DU 195 may also contain its own one or more memories and processors and / or other hardware, but these hardware are not shown.

[0016] The RAN node 170 includes a module 150, which includes one or both of the parts 150-1 and / or 150-2, which can be implemented in a variety of ways. The module 150 can be implemented in hardware as the module 150-1, for example, as part of one or more processors 152. The module 150-1 can also be implemented as an integrated circuit, or implemented 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 and executed by one or more processors 152. For example, one or more memories 155 and the computer program code 153 are configured to, together with the one or more processors 152, cause the RAN node 170 to perform one or more operations described herein. Note that the functionality of the module 150 can be distributed, for example, distributed between the DU 195 and the CU 196, or implemented only in the DU 195.

[0017] One or more network interfaces 161 communicate over a network, for example, via links 176 and 131. Two or more gNBs 170 may communicate using, for example, link 176. Link 176 may be a wired link or a wireless link or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interfaces for other standards.

[0018] 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 units of the RAN node 170 may be physically located at a different location from the RRH / DU 195, and the one or more buses 157 may be partially implemented as, for example, optical cables or other suitable network connections to connect other units of the RAN node 170 (e.g., central unit (CU) gNB-CU 196) to the RRH / DU 195. Reference 198 also indicates those suitable network links.

[0019] The RAN node / gNB may include one or more TRPs, and the methods described in this document may be applied to these TRPs. Figure 1 The RAN node 170 is shown to include two TRPs, namely, TRP 51 and TRP 52. The RAN node 170 may host or include Figure 1 Other TRPs not shown.

[0020] The relay nodes in NR are called integrated access and backhaul nodes. The mobile termination part of the IAB node facilitates the backhaul (parent link) connection. In other words, it is the function that carries the UE functionality. The distributed unit part of the IAB node facilitates the so-called access link (sub-link) connection (i.e., the connection for the access link UE, and the backhaul for other IAB nodes in the case of multi-hop IAB). In other words, it is responsible for specific base station functions. The IAB scenario can follow a so-called split architecture, where the central unit hosts the high-level protocols to the UE and terminates the control plane and user plane interfaces to the 5G core network.

[0021] Note that the description herein indicates that a "cell" performs functions, but it should be clear that the devices that form the cells can perform these functions. A cell constitutes part of a base station. That is, there can be multiple cells for each base station. For example, for a single carrier frequency and associated bandwidth, there can be three cells, each covering one-third of a 360-degree 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, while a base station can use multiple carriers. Therefore, if there are three 120-degree cells for each carrier and there are two carriers, the base station has a total of 6 cells.

[0022] The wireless network 100 may include one or more network units 190, which may include core network functions and provide a connection to another network (e.g., a telephone network and / or a data communication network (e.g., the Internet)) via one or more links 181. Such core network functions for 5G may include location management functions (LMF) and / or access and mobility management functions (AMF) and / or user plane functions (UPF) and / or session management functions (SMF). Such core network functions for LTE may include MME (mobility management entity) / SGW (serving gateway) functions. Such core network functions may include SON (self-organizing / optimizing network) functions. These are only example functions that may be supported by the network unit 190, and it is noted that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network unit 190 via a link 131. Link 131 may be implemented, for example, as an NG interface for 5G or an S1 interface for LTE or other suitable interfaces for other standards. The network unit 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / WI / F) 180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The computer program code 173 may include SON and / or MRO functionality 172.

[0023] The wireless network 100 may implement network virtualization, which is the 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, often in combination with resource virtualization. Network virtualization is categorized as: external network virtualization, combining many networks or parts of networks into virtual units; or internal network virtualization, providing network-like functions to software containers on a single system. Note that the virtualized entities produced by network virtualization are still implemented to some extent using hardware such as processors 152 or 175 and memories 155 and 171, and such virtualized entities also produce technical effects.

[0024] 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 storage devices, flash memory, magnetic storage devices and systems, optical storage devices and systems, non-transitory memory, temporary memory, fixed memory, and removable memory. Computer readable memories 125, 155, and 171 may be components 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 the following: 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 components for performing functions, such as controlling UE 110, RAN node 170, network element 190, and other functions described herein.

[0025] In general, various example embodiments of user equipment 110 may include, but are not limited to, a cellular phone (e.g., a smart phone), a tablet computer, a personal digital assistant (PDA) with wireless communication capabilities, a portable computer with wireless communication capabilities, an image capture device with wireless communication capabilities (e.g., a digital camera), a gaming device with wireless communication capabilities, a music storage and playback device with wireless communication capabilities, an Internet device that allows wireless Internet access and browsing, a tablet computer with wireless communication capabilities, a head-mounted display (e.g., a display that implements virtual / augmented / mixed reality), and a portable unit or terminal that includes a combination of these functions. UE 110 may also be a vehicle (e.g., a car) or a UE installed in a vehicle, a UAV (e.g., a drone) or a UE installed in a UAV.

[0026] UE 110, RAN node 170 and / or network element 190 (and associated memory, computer program code and modules) may be configured to (e.g., in part) implement the methods described herein, including UL SRS power control under multi-TRP operation for C-JT. Figure 1 The computer program code 123, module 140-1, module 140-2 and other units / features of the UE 110 shown in FIG. 140-1 may implement the user equipment related aspects of the methods described herein. Similarly, Figure 1 The computer program code 153, module 150-1, module 150-2 and other units / features of the RAN node 170 shown in the figure may implement the gNB / TRP related aspects of the methods described herein. Figure 1 The computer program code 173 and other units / features of the network element 190 shown in FIG. 1 may be configured to implement the network element related aspects of the methods described herein.

[0027] Therefore, having introduced a suitable but non-limiting technical context for practicing example embodiments, example embodiments are now described in more detail.

[0028] Examples described herein relate to optimization of channel estimation in multiple transmission / reception point (mTRP) communications in terms of coherent joint transmission (C-JT) and MIMO. Components of these examples include UE and gNB.

[0029] The description in this article involves both conventional LTE and current NR specifications and research projects. For example, reference is made to TR 36.819 and 36.741, which consider the CoMP principle and detail C-JT and NC-JT and dynamic reference point selection / blanking. However, the current specifications do not involve the details of the example described in this article, in which the path loss of multiple TRPs is adjusted to have more accurate and appropriate power levels.

[0030] The current standard supports adjusting the UE SRS resource set power level based on the TCI state, where in order to detect channels towards multiple TRPs, multiple SRS resource sets need to be used in sequence to detect different UE-TRP channels respectively. However, this power control does not include different path loss reference points from multiple TRPs.

[0031] In the context of the underlying issue, the information element pathlossReferenceRS is described within 38.213 and 38.331. For example, 38.331 specifies that pathlossReferenceRS is used for a reference signal set (e.g., a CSI-RS configuration or SS block) to be used for path loss estimation. Multiple candidate path loss reference RSs for SRS power control can be configured, where one candidate RS can be mapped to an SRS resource set. However, this focuses on one path loss (one TRP associated power), while the examples described herein focus more on path losses for multiple TRPs that will be adjusted to have more accurate and appropriate power levels (TRP range associated power).

[0032] Therefore, the examples described herein propose a UL transmit power control process that takes into account multiple path loss reference points obtained from multiple TRP-by-TRP TCI states so that a single SRS resource can be used to estimate an aggregated channel from a UE to multiple TRPs. The methods described herein utilize an adjusted path loss range to enable a TX power for SRS. Advantages and technical effects of the examples described herein include reduced signaling overhead and simplified implementation.

[0033] Communication of multiple transmission / reception points (TRPs) in the context of coherent joint transmission (C-JT) has again attracted attention in the technical aspects of 3GPP Rel-18 and Rel-19 proposals, first for frequency range (FR) 1 and then to be extended to FR2. Current standards already support multi-point transmission techniques through coordinated multi-point (CoMP) and dynamic point selection / blanking via LTE (Rel-11), which have been further extended to support non-coherent joint transmission (NC-JT). However, the LTE-based CoMP standards need to be updated to enable NR to support C-JT. The NR standards also introduced support for multiple MTRP schemes in Rel-16, which are based on time division (TDM), frequency division (FDM) and space division (SDM) multiplexing of transmission resources. In particular, the MTRP SDM scheme with full overlap of time and frequency resources applied to PDSCH transmission can take two different forms: NCJT, where each MIMO layer is transmitted from the antenna port of a single TRP; and CJT, where each layer can be transmitted from the antennas of multiple TRPs. Unlike NCJT, CJT requires phase synchronization between TRPs. Rel-17 introduced CSI reporting for NCJT based on Type I CSI reporting. Rel-18 will extend support for CJT transmission for both FDD and TDD operations. In the case of TDD operation, the extension will be based on SRS enhancement to help gNB derive downlink (DL) precoding weights from SRS-based uplink (UL) channel estimates.

[0034] One area that needs to be upgraded is the uplink (UL) channel sounding using the sounding reference signal (SRS) when acquiring the channel matrix in a multi-TRP scenario. Specifically, uplink power control in the current standard aims to mitigate path loss by adjusting the user equipment (UE) power based on the reference point found in the transmission configuration indicator (TCI) state of a single TRP. Therefore, in a multi-TRP setup (where multiple TCI states can exhibit different path loss reference points based on individual UE-TRP links), the channel sounding process will have to traverse all the different TRPs in sequence to obtain the individual channels between the UE and all TRPs, resulting in a significant increase in overhead.

[0035] In the current NR standard for UL channel sounding via SRS transmission, the UE adjusts its UL SRS transmit power for all resources within the UL SRS set based on a single pathlossReferenceRS, i.e., a DL reference signal / signal (e.g., NZP-CSI-RS or SSB) established by a single (serving) TRP that is common to all resources within the UL SRS set. In a multi-TRP setting, the path losses of different TRPs are not necessarily represented by the single DL pathlossReferenceRS. Therefore, since only a single pathloss reference can be configured for the UL SRS resource set, i.e., the UE uplink transmit power is adjusted based on a single TRP, the transmit power may not correspond to the optimal power level towards other TRPs. On the one hand, when the UE transmit power is adjusted based on a nearby TRP (i.e., a low transmit power corresponding to a low pathloss), the signal level at the far TRP is further reduced compared to the case where the UE transmits at maximum power. On the other hand, when the UE transmit power is adjusted based on the far TRP (i.e., high transmit power corresponding to high path loss), the signal level at the nearby TRP may saturate the automatic gain control, resulting in a near-far problem when multiple UEs need to be served.

[0036] Therefore, in order to successfully detect multiple TRP channels, multiple SRS resource sets must be configured. These sets are sent sequentially, which results in a large amount of channel acquisition overhead. This overhead is further multiplied if port switching is required at the UE (e.g., if the UE has more ports than TRPs and needs to traverse the ports to obtain per-port channel information).

[0037] Furthermore, the process forms separate links (multiple channel matrices) between the UE and all TRPs, while a single link (i.e., a single channel matrix) to a “virtual” gNB with multiple geographically separated antennas is more convenient for C-JT operations.

[0038] The current 3GPP NR standard supports multi-TRP transmission techniques such as C-JT and dynamic point selection / blanking [TR36.819] and NC-JT [TR36.741].

[0039] The current standard supports adjusting the UE SRS resource set power level based on the TCI state. However, this power control does not include different path loss reference points from multiple TRPs. Therefore, in order to detect channels towards multiple TRPs, multiple SRS resource sets need to be used in sequence to detect different UE-TRP channels respectively. The standard does not support joint SRS power control based on multiple different path loss reference points.

[0040] This paper describes a new UL transmit power control procedure that takes into account multiple path loss reference points obtained from multiple per-TRP TCI states so that a single SRS resource can be used to estimate the aggregate channel from a UE to multiple TRPs.

[0041] In brief, this document describes the use of a single transmit power level associated with an SRS transmission to simultaneously probe channels for all TRPs within a service set.

[0042] The power level is set based on a joint metric of the path loss reference points. These resources are obtained from the path loss reference RS associated with the TCI states (per TRP), which are used to configure the SRS resources to be sent. In order to consider all target TRPs, the TRP with the highest path loss needs to be a reference, or the TRP must be discarded from the active set. The power level should also take into account nearby TRPs so that they are not saturated by excessive UE power usage. These two points imply a clear path loss range (or conversely, a suitable power range for the received signal) within which the UE can be served via C-JT. The gNB can set this power range (for example, based on its ability to withstand low and high SNR levels) to inform the UE of its active TRP set. Once the UE transmit power is configured (i.e., the UE reports the index of the TRP in which the SNR with the configured transmit power is lower than the required minimum SNR), the active TRP set can be restricted.

[0043] In any example embodiments herein, an "active TRP set" may be referred to simply as a "TRP set" (eg, instead of an active TRP set). Similarly, any "active set" may be referred to simply as a "set."

[0044] Using a single power level for SRS transmissions makes path loss information implicit in the channel matrix estimated at the gNB (i.e., the relative path loss difference between TRPs), which can then be more accurately accounted for when formulating the downlink precoding matrix for C-JT.

[0045] C-JT in a multi-TRP setting requires accurate channel knowledge (gain / loss and phase information) between the UE and all TRPs belonging to the C-JT service set. The current standard supports separately probing these UE-TRP links by configuring separate SRS resource sets (each with different power control) for uplink probing. The SRS resource sets are configured with transmit power levels based on the TCI state per TRP (or more specifically, the pathlossReferenceRS parameter in the TCI state power control parameters). Intuitively, the UE transmit power for SRS transmission is adjusted to compensate for the path loss. This mode of operation results in a lot of overhead because all links need to be probed separately in a time-division manner. In addition, if the UE needs to switch antenna ports, the overhead will be further multiplied.

[0046] For more efficient channel detection, a single SRS resource set is configured that is received simultaneously by all service sets TRP. This mode of operation requires the use of a single transmit power calculated / adjusted based on multiple TCI states or multiple path loss parameters, which is not supported by current standards.

[0047] The power level can be based on a joint metric of the path loss reference points indicated to the SRS resource to be transmitted (for K TRPs in the active set, based on the pathlossReferenceRS values ​​of TCI#1 to TCI#K). Condition 1: The pathlossReferenceRS corresponding to the highest path loss (e.g., the highest RSRP) within the active set including K TRPs needs to be the reference point. Otherwise, the SRS transmission cannot reach the TRP with the highest path loss. Condition 2: The pathlossReferenceRS corresponding to the lowest path loss (e.g., the lowest RSRP) within the active set including K TRPs needs to be the reference point. Otherwise, nearby TRPs will eavesdrop on the SRS transmission, saturating the AGC and causing near-far problems for other UEs served by the TRP. The set of active TRPs should be adjusted so that conditions 1 and 2 hold. For example, condition 1 needs to hold, otherwise the channel estimation accuracy is reduced. In addition, for example, condition 2 needs to hold to best avoid AGC saturation.

[0048] Thus, conditions 1 and 2 define a path loss range within which a UE can be served via C-JT. Conversely, there is a tolerance range for receive power that allows successful channel sounding (i.e., minimum SNR) without saturating the AGC at the receive TRP (i.e., maximum UE transmit power). Figure 2A and Figure 2B This range is shown in .

[0049] Figure 2AA configuration is shown in which UE 110 communicates with TRP#1 251 at PL#1 201, communicates with TRP#2 252 at PL#2 202, communicates with TRP#3 253 at PL#3 203, and communicates with TRP#4 254 at PL#4 204. Figure 2A In the example, two TRPs (e.g., TRP 251 and TRP 252) may be used for one gNB (e.g., serving cell) (e.g., RAN node 170), while the other two TRPs (e.g., TRP 253 and TRP 254) may be used for another cell / gNB (different PCI from the serving cell) (e.g., another RAN node), or all TRPs (e.g., TRP 251, TRP 252, TRP 253, TRP 254) may be associated with the same cell (e.g., a cell hosted by RAN node 170). Therefore, Figure 2A are generalized so that they are TRPs, which can be associated with the same or different PCIs.

[0050] exist Figure 2B , a single UE transmit power 210 (upward arrow) is used to compensate for multiple path losses (downward arrow), including path loss #1 201, path loss #2 202, path loss #3 203, and path loss #4 204. Region 213 highlights the receive power tolerance range (conversely, the path loss range). Because the AGC saturation condition 212 is not as strict as the minimum SNR condition 214, the channels to TRP #1 251, to TRP #2 252, and to TRP #3 253 can be simultaneously detected with slight AGC saturation of TRP #1 251. However, the path loss 204 of TRP #4 254 is too high for accurate channel estimation.

[0051] This range 213 can also be used to dynamically adjust the active TRP set. Once the UE transmit power for the SRS resource set is configured, the UE 110 can determine which TRPs in the active set are below the minimum SNR 214. This is done by reporting the indexes 216 of these TRPs via uplink signaling (in Figure 2B In the case of TRP#4, index 254), the gNB (e.g., 170) may decide to restrict the active set. Figure 2B Also shown in FIG. 2 is a nominal Rx power target 218 .

[0052] It is also possible to tune the AGC differently at different TRPs. In this case, the amplification level should be considered during channel estimation and aggregate channel calculation. If different AGC levels are utilized, the UE should be informed of the saturation tolerance for UL power control.

[0053] Using a single power level for SRS transmissions allows path loss information (i.e., relative path loss difference between TRPs) to be implicit in the channel matrix estimated at gNB 170. Therefore, instead of estimating multiple separate normalized channel matrices, i.e., H1, H2, ..., H K , but estimates a single aggregate channel matrix, namely H' = [α1H1α2H2…α K H K ], where from α1 to α K to reflect the combined effect of path loss and AGC level. This allows more accurate consideration of channel gain (relative to path loss between AGC level and TRP) when expressing the downlink precoding matrix for C-JT based on H'.

[0054] For various strategies regarding UL power adjustment, embodiments include minimum UE power usage, limited maximum UE power, and adjusting power based on the root mean square of path loss.

[0055] Minimum UE power usage: Limit the active set to N ≥ 1 TRPs with the best path loss values. Then, adjust the UE transmit power to the minimum level where the N TRPs can receive the UE transmission with sufficient signal power. This strategy minimizes UE power usage. Figure 3A This strategy is shown in . The "UE TX Power" text arrangement 302 marks the path loss level (now PL#2) used to define the transmit power.

[0056] Limited maximum UE power: Transmit at the maximum power that does not saturate any nearby TRPs, thus achieving the highest possible number of TRPs in the Active Set. This requires knowledge of the AGC saturation tolerance at the UE 110, which is signaled via downlink signaling (e.g., in the form of "nominal power + R dB", where R is indicated to the UE 110, either explicitly or implicitly, where the nominal power is added to R, where R is the AGC saturation tolerance). This strategy allows for a maximum Active Set size without saturation. Figure 3B The strategy is shown in . The transmit power of the strategy is marked at item 304 .

[0057] Adjusting power based on RMS path loss: The RMS metric will prioritize TRPs at average distances and give less weight to extreme TRPs (i.e., TRPs with very low and very high path losses). Adjusting UE power based on the RMS value will enable UE 110 to reach TRPs at average distances, but will cause some saturation at nearby TRPs. Far-end TRPs cannot accurately estimate the channel and should be dropped from the active set. Figure 3C The strategy is shown in . The transmit power of the strategy is marked at item 306 , and the RMS PL is marked as item 308 .

[0058] Advantages and technical effects of the examples described herein include the following 1-2. 1. Instead of configuring multiple SRS resource sets to individually probe all UE-TRP channels within the active set, only a single SRS resource set is configured. This approach significantly reduces channel probing overhead, especially when the UE must perform port switching. 2. Instead of individually probing UE-TRP channels at different uplink powers, using a single power level for SRS transmission makes path loss information implicit in the channel matrix estimated at the gNB (i.e., the relative path loss difference between TRPs), which can then be more accurately considered when formulating the downlink precoding matrix for C-JT.

[0059] In an example embodiment herein, the proposed UL PC method for C-JT can be used for different UL SRS use cases such as antenna switching, codebook, non-codebook, beam management and positioning. It should be noted that the use of any method is not limited to a specific use case.

[0060] In any embodiment of the present invention, multiple transmission and reception points (TRPs) may be identified by CORESETPoolIndex (CORESET set), group index (e.g., CORESET group index), logical group index (e.g., CORSET set in a group). As an example, the above-mentioned group / set / CORESETpoolIndex may be configured with separate TCI states / indicated TCI states (these TCI states may be unified TCI states, where the TCI state may indicate the transmission and / or reception assumption associated with the group / set / poolindex), so for UL transmission (and DL), there may be more than one active and indicated TCI state (e.g., multiple active and indicated TC1 states), and the UE may determine different TCI states to correspond to transmission / reception to different TRPs.

[0061] Figure 4 An example apparatus 400 is provided, which may be implemented in hardware, configured to implement the examples described herein. The apparatus 400 includes at least one processor 402 (e.g., an FPGA and / or a CPU), at least one memory 404 including computer program code 405, wherein the at least one memory 404 and the computer program code 405 are configured to, together with the at least one processor 402, cause the apparatus 400 to implement circuits, processes, components, modules, or functions (collectively referred to as controls 406) to implement the examples described herein, including UL SRS power control under multi-TRP operation for C-JT. The memory 404 may be a non-transitory memory, a temporary memory, a volatile memory (e.g., a RAM), or a non-volatile memory (e.g., a ROM).

[0062] The device 400 optionally includes a display and / or I / O interface 408, which can be used to display aspects or states of the methods described herein (e.g., when one of the methods is being executed or at a subsequent time), or to receive input from a user, such as using a keypad, camera, touch screen, touch area, microphone, biometrics, etc. The device 400 includes one or more communication (e.g., network (N / W)) interfaces (I / F) 410. The communication interface 410 can be wired and / or wireless and communicates through the Internet / other networks via any communication technology. The communication interface 410 may include one or more transmitters and one or more receivers. The communication interface 410 may include standard well-known components, such as amplifiers, filters, frequency converters, modulators (demodulators), encoder / decoder circuits, and one or more antennas.

[0063] The apparatus 400 implementing the functionality of the control 406 may be a UE 110, a RAN node 170 (e.g., a gNB), or a network element 190. Thus, the processor 402 may correspond to the processor 120, the processor 152, and / or the processor 175, the memory 404 may correspond to the memory 125, the memory 155, and / or the memory 171, the computer program code 405 may correspond to the computer program code 123, the module 140-1, the module 140-2, and / or the computer program code 153, the module 150-1, the module 150-2, and / or the computer program code 173, and the communication interface 510 may correspond to the transceiver 130, the antenna 128, the transceiver 160, the antenna 158, the network interface 161, and / or the network interface 180. Alternatively, the apparatus 400 may not correspond to any of the UE 110, the RAN node 170, or the network element 190, because the apparatus 400 may be part of a self-organizing / optimizing network (SON) node, for example, in the cloud.

[0064] The apparatus 400 may also be distributed throughout the network (eg, 100), including within and between the apparatus 40 and any network elements (eg, a network control unit (NCE) 190 and / or a RAN node 170 and / or a UE 110).

[0065] like Figure 4As shown in , interface 412 enables data communication between various items of device 400. For example, interface 412 can be one or more buses, such as address, data or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fiber or other optical communication devices, etc. Computer program code 405 (including control 406) can include object-oriented software configured to pass data / messages between objects within computer program code 405. Device 400 need not include each of the features described, or may also include other features.

[0066] Figure 5 An example method 500 for implementing the example embodiments described herein is provided. At 510, the method includes receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission. At 520, the method includes obtaining a plurality of path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers. At 530, the method includes determining a transmit power level for the sounding reference signal resource transmission based on a joint metric of the plurality of path loss reference points to sound a channel for the plurality of transmission and reception points. At 540, the method includes determining a set of transmission and reception points from the plurality of transmission and reception points based on the determined transmit power level. At 550, the method includes sending uplink data or reference signals or control information from a user equipment to the plurality of transmission and reception points within the set based on the determined transmit power level using the one or more sounding reference signal resources. The method 500 may be performed using a user equipment (e.g., UE 110).

[0067] Figure 6 is an example method 600 for implementing the example embodiments described herein. At 610, the method includes: estimating an aggregated channel using a transmit power level associated with a sounding reference signal transmission, the sounding reference signal transmission being used to sound a channel for a transmission and reception point within a set including a plurality of transmission and reception points. At 620, the method includes: wherein the transmit power level is based on a joint metric of a plurality of path loss reference points according to one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points, wherein the plurality of transmission and reception points have the same or different physical cell identifiers. At 630, the method includes: determining a downlink precoding matrix for coherent joint transmission using the estimated aggregated channel. The method 600 may be performed using a network node (e.g., a RAN node 170).

[0068] The following examples (1-51) are provided and described herein.

[0069] Example 1. 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, enable the apparatus to at least: receive a sounding reference signal configuration comprising one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtain multiple path loss reference points from one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and receiving points having the same or different physical cell identifiers; determine a transmission power level for sounding reference signal resource transmission based on a joint measurement of the multiple path loss reference points to detect channels for the multiple transmission and receiving points; determine a set of transmission and receiving points among the multiple transmission and receiving points based on the determined transmission power level; and use the one or more sounding reference signal resources to send uplink data or reference signals or control information from a user equipment to the multiple transmission and receiving points within the set based on the determined transmission power level.

[0070] Example 2. An apparatus according to Example 1, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: perform corresponding measurements of corresponding channels of multiple transmission and reception points; and determine one or more subsets of the multiple transmission and reception points based on the corresponding measurements of the corresponding channels of the multiple transmission and reception points.

[0071] Example 3. An apparatus according to any one of Examples 1 to 2, wherein at least one memory and a computer program code are configured to, together with at least one processor, enable the apparatus to at least: perform corresponding measurements of corresponding channels of multiple transmission and reception points; report corresponding measurements of corresponding channels of multiple transmission and reception points to a network node; and based on the report, receive a sounding reference signal configuration.

[0072] Example 4. An apparatus according to any one of Examples 1 to 3, wherein at least one memory and a computer program code are configured to, together with at least one processor, cause the apparatus to at least: perform corresponding measurements of corresponding channels of multiple transmission and reception points; determine one or more subsets of the multiple transmission and reception points based on the corresponding measurements of the corresponding channels of the multiple transmission and reception points; report one or more subsets of the multiple transmission and reception points to a network node; and receive a sounding reference signal configuration based on the report.

[0073] Example 5. An apparatus according to any one of Examples 1 to 4, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: report at least one index of one of a plurality of transmission and reception points, and for at least one index, a quality metric of one of a plurality of transmission and reception points having a transmission power level that is lower than a threshold value related to the quality metric.

[0074] Example 6. The apparatus of Example 5, wherein the quality metric comprises a reference signal received power.

[0075] Example 7. An apparatus according to any of Examples 5 to 6, wherein the quality metric includes a signal-to-noise ratio.

[0076] Example 8. An apparatus according to any one of Examples 1 to 7, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a collection based on a range within which a user device is served using coherent joint transmissions from multiple transmission and reception points.

[0077] Example 9. An apparatus according to Example 8, wherein: the range is defined based on a first condition and a second condition; the first condition includes a path loss reference signal resource corresponding to a highest reference signal received power value within a set being used as a first reference point for the range; and the second condition includes a path loss reference signal resource corresponding to a lowest reference signal received power value within the set being used as a second reference point for the range.

[0078] Example 10. An apparatus according to Example 9, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: adjust a set so that a first condition is satisfied for uplink data or reference signal or control information transmission from a user equipment to transmission and reception points within the set.

[0079] Example 11. An apparatus according to any one of Examples 9 to 10, wherein a first condition is satisfied for uplink data or reference signal or control information transmission from a user equipment to transmission and reception points within a set.

[0080] Example 12. An apparatus according to any one of Examples 9 to 11, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: adjust the set so that for uplink data or reference signal or control information transmission from a user device to at least one of the transmission and reception points within the set, the second condition is not satisfied, and for uplink data or reference signal or control information transmission from a user device to at least another of the transmission and reception points within the set, the second condition is satisfied.

[0081] Example 13. An apparatus according to any one of Examples 9 to 12, wherein the second condition is not satisfied for uplink data or reference signal or control information transmission from a user device to at least one of the transmission and reception points in the set, and the second condition is satisfied for uplink data or reference signal or control information transmission from a user device to at least another of the transmission and reception points in the set.

[0082] Example 14. An apparatus according to any of Examples 8 to 13, wherein the range is defined using at least one automatic gain control saturation tolerance as a first reference point and using a minimum signal-to-noise ratio as a second reference point.

[0083] Example 15. An apparatus according to Example 14, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: adjust the set so that uplink data or reference signal or control information transmission from the user equipment to at least one of the multiple transmission and reception points within the set exceeds at least one automatic gain control saturation tolerance, and uplink data or reference signal or control information transmission from the user equipment to at least another of the transmission and reception points within the set does not exceed the automatic gain control saturation tolerance.

[0084] Example 16. An apparatus according to any one of Examples 14 to 15, wherein uplink data or reference signal or control information transmission from a user device to at least one of the transmission and reception points within a set exceeds at least one automatic gain control saturation tolerance, and uplink data or reference signal or control information transmission from a user device to at least another of the transmission and reception points within the set does not exceed the automatic gain control saturation tolerance.

[0085] Example 17. An apparatus according to any of Examples 14 to 16, wherein different automatic gain control saturation tolerance levels are used for different transmission points in the plurality of transmission and reception points.

[0086] Example 18. An apparatus according to Example 17, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: receive different automatic gain control saturation tolerance levels; and adjust a set for power control based on the received different automatic gain control saturation tolerance levels.

[0087] Example 19. An apparatus according to any of Examples 8 to 18, wherein the range is defined based on a received power tolerance.

[0088] Example 20. An apparatus according to any one of Examples 1 to 19, wherein the transmit power level is determined to compensate for multiple path losses associated with multiple path loss reference points.

[0089] Example 21. An apparatus according to any of Examples 1 to 20, wherein the transmit power level is configured to be used to estimate an aggregate channel from a user equipment to multiple transmission and reception points.

[0090] Example 22. An apparatus according to any one of Examples 1 to 21, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine path loss values ​​for multiple transmission and reception points using multiple path loss reference points; limit the set to the transmission and reception points with the highest path loss values; and adjust the transmit power level to the minimum level at which the transmission and reception points within the set can receive transmissions from user equipment with sufficient signal power.

[0091] Example 23. An apparatus according to any one of Examples 1 to 22, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: receive downlink signaling including information related to an automatic gain control saturation tolerance level; and determine a transmit power level so that the automatic gain control saturation tolerance level is not exceeded during transmission of uplink data or reference signals or control information.

[0092] Example 24. The apparatus of Example 23, wherein the downlink signaling is in the form of "nominal power + R db", where R corresponds to an automatic gain control saturation tolerance level.

[0093] Example 25. An apparatus according to any one of Examples 1 to 23, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a root mean square of path losses associated with multiple path loss reference points; and use the determined root mean square to determine a transmit power level.

[0094] Example 26. An apparatus according to Example 25, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: assign a higher priority to transmission and reception points that are at an average distance from the user equipment than to transmission and reception points that are relatively far away from the user equipment.

[0095] Example 27. The apparatus of Example 26, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: remove transmission and reception points relatively far from the user equipment from the set.

[0096] Example 28. 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 at least: estimate an aggregated channel using a transmit power level associated with a sounding reference signal transmission used to sound a channel for a transmission and reception point within a set comprising multiple transmission and reception points; wherein the transmit power level is based on a joint measurement of multiple path loss reference points based on one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and reception points, wherein the multiple transmission and reception points have the same or different physical cell identifiers; and determine a downlink precoding matrix for coherent joint transmission using the estimated aggregated channel.

[0097] Example 29. The apparatus of Example 28, wherein the aggregated channel is estimated as an aggregated channel matrix.

[0098] Example 30. The apparatus of Example 29, wherein the downlink precoding matrix is ​​determined using an aggregated channel matrix.

[0099] Example 31. An apparatus according to any one of Examples 28 to 30, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: receive a report of at least one index of a plurality of transmission and reception points, for which, for at least one index, a quality metric of one of the plurality of transmission and reception points having a transmit power level is below a threshold associated with the quality metric.

[0100] Example 32. An apparatus according to Example 31, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: remove one transmission and reception point of the plurality of transmission and reception points associated with at least one index from the set.

[0101] Example 33. An apparatus according to any of Examples 31 to 32, wherein the quality metric includes a reference signal received power.

[0102] Example 34. An apparatus according to any one of Examples 31 to 33, wherein the quality metric includes a signal-to-noise ratio.

[0103] Example 35. An apparatus according to any one of Examples 28 to 34, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: send a sounding reference signal configuration comprising one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission.

[0104] Example 36. An apparatus according to Example 35, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a transmit power level, the transmit power level being associated with a sounding reference signal resource transmission.

[0105] Example 37. An apparatus according to any one of Examples 28 to 36, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a set of factors to be applied to a channel matrix of one or more reference signal resources associated with multiple transmission configuration indicator states; wherein the factors within the factor set reflect the combined effects of corresponding path losses and corresponding automatic gain control levels of multiple path loss reference points; and wherein an aggregated channel matrix of aggregated channels is estimated as a combination of channel matrices after the factor set is applied accordingly to the channel matrix.

[0106] Example 38. An apparatus according to any one of Examples 28 to 37, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a set of transmission and reception points based on a range within which a user device is served using coherent joint transmissions from multiple transmission and reception points.

[0107] Example 39. An apparatus according to Example 38, wherein: the range is defined based on a first condition and a second condition; the first condition includes a path loss reference signal resource corresponding to a highest reference signal received power value within a set being used as a first reference point for the range; and the second condition includes a path loss reference signal resource corresponding to a lowest reference signal received power value within the set being used as a second reference point for the range.

[0108] Example 40. An apparatus according to any one of Examples 28 to 39, wherein at least one memory and a computer program code are configured to, together with at least one processor, cause the apparatus to at least: receive a report of corresponding measurements of corresponding channels of multiple transmission and reception points from a user equipment; and based on the report, determine a sounding reference signal configuration for the user equipment; wherein the sounding reference signal configuration is configured to be used with the user equipment to send uplink data or reference signals or control information from the user equipment to multiple transmission and reception points within a set based on a transmit power level; and send the sounding reference signal configuration to the user equipment.

[0109] Example 41. An apparatus according to any one of Examples 28 to 40, wherein at least one memory and a computer program code are configured to, together with at least one processor, cause the apparatus to at least: perform corresponding measurements of corresponding channels of multiple transmission and reception points; receive reports of one or more subsets of the multiple transmission and reception points from a user equipment based on the corresponding measurements of the corresponding channels of the multiple transmission and reception points; determine a sounding reference signal configuration for the user equipment based on the report; wherein the sounding reference signal configuration is configured to be used with the user equipment to send uplink data or reference signals or control information from the user equipment to multiple transmission and reception points within a set based on a transmit power level; and send the sounding reference signal configuration to the user equipment.

[0110] Example 42. A method comprising: receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining multiple path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and receiving points having the same or different physical cell identifiers; determining a transmit power level for sounding reference signal resource transmission based on a joint measurement of the multiple path loss reference points to detect channels for the multiple transmission and receiving points; determining a set of transmission and receiving points among the multiple transmission and receiving points based on the determined transmit power level; and using the one or more sounding reference signal resources, based on the determined transmit power level, sending uplink data or reference signals or control information from a user equipment to the multiple transmission and receiving points within the set.

[0111] Example 43. A method comprising: estimating an aggregate channel using a transmit power level associated with a sounding reference signal transmission, the sounding reference signal transmission being used to sound a channel for a transmission and reception point within a set including multiple transmission and reception points; wherein the transmit power level is based on a joint measurement of multiple path loss reference points based on one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and reception points, wherein the multiple transmission and reception points have the same or different physical cell identifiers; and determining a downlink precoding matrix for coherent joint transmission using the estimated aggregate channel.

[0112] Example 44. A non-temporary program storage device readable by a machine, which tangibly embodies an instruction program that can be executed by the machine to perform operations, the operations including: receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining multiple path loss reference points from one or more reference signal resources, one or more reference signal resources are associated with multiple transmission configuration indicator states, and the multiple transmission configuration indicator states are associated with multiple transmission and reception points with the same or different physical cell identifiers; based on a joint measurement of the multiple path loss reference points, determining a transmission power level for the transmission of the sounding reference signal resources to detect channels for multiple transmission and reception points; based on the determined transmission power level, determining a set of transmission and reception points among the multiple transmission and reception points; and using the one or more sounding reference signal resources, based on the determined transmission power level, sending uplink data or reference signals or control information from a user equipment to the multiple transmission and reception points in the set.

[0113] Example 45. A non-transitory program storage device readable by a machine, tangibly embodying an instruction program executable by the machine for performing operations, the operations comprising: estimating an aggregated channel using a transmit power level associated with a sounding reference signal transmission, the sounding reference signal transmission being used to sound a channel for a transmission and reception point within a set comprising multiple transmission and reception points; wherein the transmit power level is based on a joint measurement of multiple path loss reference points based on one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and reception points, wherein the multiple transmission and reception points have the same or different physical cell identifiers; and determining a downlink precoding matrix for coherent joint transmission using the estimated aggregated channel.

[0114] Example 46. An apparatus comprising: a component for receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; a component for obtaining multiple path loss reference points from one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and receiving points having the same or different physical cell identifiers; a component for determining a transmit power level for sounding reference signal resource transmission based on a joint measurement of multiple path loss reference points to detect channels for multiple transmission and receiving points; a component for determining a set of transmission and receiving points among multiple transmission and receiving points based on the determined transmit power level; and a component for sending uplink data or reference signals or control information from a user equipment to multiple transmission and receiving points within the set based on the determined transmit power level using the one or more sounding reference signal resources.

[0115] Example 47. An apparatus comprising: a component for estimating an aggregated channel using a transmit power level associated with a sounding reference signal transmission, the sounding reference signal transmission being used to sound a channel for a transmission and reception point within a set including multiple transmission and reception points; wherein the transmit power level is based on a joint measurement of multiple path loss reference points based on one or more reference signal resources, the one or more reference signal resources being associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states being associated with multiple transmission and reception points, wherein the multiple transmission and reception points have the same or different physical cell identifiers; and a component for determining a downlink precoding matrix for coherent joint transmission using the estimated aggregated channel.

[0116] Example 48. An apparatus according to any one of Examples 1 to 27, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: receive a set of path loss reference signals using a user equipment; and measure the path loss reference signals using the user equipment.

[0117] Example 49. An apparatus according to Example 48, wherein at least one memory and computer program code are configured to, together with at least one processor, cause the apparatus to at least: determine a subset of a path loss reference signal based on a metric using a user device; and determine a transmit power level for a detection reference signal transmission based on the determined subset using the user device.

[0118] Example 50. An apparatus according to Example 48, wherein at least one memory and a computer program code are configured to, together with at least one processor, cause the apparatus to at least: use a user device to report the results of a measurement of a path loss reference signal; use the user device to receive a subset of the path loss reference signal from a network node; and use the user device to determine a transmission power level for a detection reference signal transmission based on the received subset.

[0119] Example 51. An apparatus according to Example 50, wherein the network node includes a gNB.

[0120] References to "computers," "processors," etc. should be understood to include not only computers with different architectures (e.g., single / multi-processor architectures and sequential or parallel architectures), but also special-purpose circuits (e.g., field-programmable gate arrays (FPGAs), application-specific circuits (ASICs), signal processing devices, and other processing circuits). References to computer programs, instructions, code, etc. should be understood to include software or firmware for programmable processors, such as the programmable content of hardware devices, whether instructions for a processor or configuration settings for a fixed-function device, gate array, or programmable logic device, etc.

[0121] The memory as described herein may be implemented using any suitable data storage technology including, for example, semiconductor-based storage devices, flash memory, magnetic storage devices and systems, optical storage devices and systems, non-transitory memory, transient memory, fixed memory, and removable memory. The memory may include a database for storing data.

[0122] As used herein, the term "circuitry" may refer to the following: (a) a hardware circuit implementation, such as an implementation in analog and / or digital circuits, and (b) a combination of circuitry and software (and / or firmware), such as (as applicable): a combination of (i) a processor or (ii) a portion of a processor / software, including a digital signal processor, software, and memory, which work together to enable the device to perform various functions, and (c) a circuit, such as a microprocessor or a portion of a microprocessor, which requires software or firmware to operate even if the software or firmware is not physically present. As a further example, as used herein, the term "circuitry" would also cover an implementation of only a processor (or multiple processors) or a portion of a processor and its accompanying software and / or firmware. The term "circuitry" would also cover (for example and if applicable to the particular element) a baseband integrated circuit or an application processor integrated circuit of a mobile phone, or a similar integrated circuit in a server, a cellular network device, or another network device.

[0123] In the figures, arrows between individual blocks indicate operational couplings therebetween and the direction of data flow over these couplings.

[0124] It should be understood that the above description is illustrative only. Various alternatives and modifications may be designed by those skilled in the art. For example, the features described in the various dependent claims may be combined with each other in any suitable combination. In addition, the features from the different example embodiments described above may be selectively combined into new example embodiments. Therefore, this description is intended to include all such alternatives, modifications, and variations that fall within the scope of the appended claims.

[0125] The following acronyms and abbreviations that may appear in the present specification and / or drawings are defined as follows (abbreviations and acronyms may be appended to each other or to other characters using, for example, a dash or a hyphen):

[0126] 3GPP Third Generation Partnership Project

[0127] 4G Fourth Generation

[0128] 5G Fifth Generation

[0129] 5GC 5G Core Network

[0130] AGC Automatic Gain Control

[0131] AMF Access and Mobility Management Function

[0132] ASIC Application-Specific Integrated Circuit

[0133] C-JT or CJT Coherent Joint Transmission

[0134] CoMP Coordinated Multipoint

[0135] CORESET Control Resource Set

[0136] config

[0137] CPU Central Processing Unit

[0138] CSI Channel State Information

[0139] CU Central Unit or Centralized Unit

[0140] DL Downlink

[0141] DSP Digital Signal Processor

[0142] eNB Evolved Node B (e.g. LTE base station)

[0143] EN-DC E-UTRAN New Radio - Dual Connectivity

[0144] The en-gNB provides NR user plane and control plane protocol termination to the UE and acts as a secondary node in EN-DC. Node of Node

[0145] E-UTRA Evolved Universal Terrestrial Radio Access, also known as LTE radio access technology

[0146] E-UTRAN E-UTRA Network

[0147] F1 Interface between CU and DU

[0148] FDD Frequency Division Duplex

[0149] FDM Frequency Division Multiplexing

[0150] FPGA Field Programmable Gate Array

[0151] FR Frequency Range

[0152] gNB 5G / NR base station, i.e., providing NR user plane and control plane protocol termination to the UE and Nodes connected to 5GC via NG interface

[0153] IAB Integrated Access and Backhaul

[0154] ID Identifier

[0155] I / F Interface

[0156] I / O Input / Output

[0157] LMF Location Management Function

[0158] LTE Long Term Evolution (4G)

[0159] MAC Media Access Control

[0160] MIMO Multiple Input Multiple Output

[0161] MME Mobility Management Entity

[0162] MRO Mobility Robustness Optimization

[0163] mTRP or MTRP Multiple Transmission / Reception Points

[0164] MU Multi-User

[0165] N TRP quantity

[0166] NCE Network Control Unit

[0167] NC-JT or NCJT Non-coherent joint transmission

[0168] Ng or NG New Generation

[0169] ng-eNB Next Generation eNB

[0170] NG-RAN Next Generation Radio Access Network

[0171] NR New Radio (5G)

[0172] N / W Network

[0173] NZP Non Zero Power

[0174] P Power

[0175] PC Power Control

[0176] PCI Physical Cell ID

[0177] PDA Personal Digital Assistant

[0178] PDCP Packet Data Convergence Protocol

[0179] PDSCH Physical Downlink Shared Channel

[0180] PHY Physical Layer

[0181] PL Path Loss

[0182] R AGC saturation tolerance level

[0183] RAM Random Access Memory

[0184] RAN Radio Access Network

[0185] RAN1 RAN Meeting

[0186] Rel- version

[0187] RLC Radio Link Control

[0188] RMS root mean square

[0189] ROM Read Only Memory

[0190] RRC Radio Resource Control (protocol)

[0191] RS reference signal

[0192] RSRP Reference Signal Received Power

[0193] RU Radio Unit

[0194] Rx or RX Receiver or Receiver

[0195] SDM Space Division Multiplexing

[0196] SGW Service Gateway

[0197] SMF session management functions

[0198] SNR Signal to Noise Ratio

[0199] SON self-organizing / optimizing network

[0200] SRS Sounding Reference Signal

[0201] SS Sync Signal

[0202] SU Single User

[0203] TCI Transmission Configuration Indicator

[0204] TDD Time Division Duplex

[0205] TDM Time Division Multiplexing

[0206] TR Technical Report

[0207] TRP Transmission and / or Reception Point

[0208] TS Technical Specifications

[0209] Tx or TX transmitter or transmission

[0210] Type I Codebook designed for SU or MU-MIMO

[0211] UAV

[0212] UE User Equipment (e.g. wireless device, usually a mobile device)

[0213] UL Uplink

[0214] UPF User Plane Function

[0215] X2 Network interface between RAN nodes and between RAN and core network

[0216] Xn Network interface between NG-RAN nodes

Claims

1. A device comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least: receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining a plurality of path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers; determining a transmit power level for transmission of the sounding reference signal resource based on a joint metric of the plurality of path loss reference points to sound channels for the plurality of transmission and reception points; determining a set of transmission and reception points in the plurality of transmission and reception points based on the determined transmission power level; and Using the one or more sounding reference signal resources, uplink data or reference signals or control information are sent from the user equipment to the plurality of transmission and reception points in the set based on the determined transmit power level.

2. The device according to claim 1, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: performing respective measurements of respective channels of the plurality of transmission and reception points; as well as One or more subsets of the plurality of transmission and reception points are determined based on respective measurements of respective channels of the plurality of transmission and reception points.

3. The device according to any one of claims 1 to 2, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: performing respective measurements of respective channels of the plurality of transmission and reception points; reporting respective measurements of respective channels of the plurality of transmission and reception points to a network node; and Based on the report, the sounding reference signal configuration is received.

4. The device according to any one of claims 1 to 3, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: performing respective measurements of respective channels of the plurality of transmission and reception points; determining one or more subsets of the plurality of transmission and reception points based on respective measurements of respective channels of the plurality of transmission and reception points; reporting the one or more subsets of the plurality of transmission and reception points to a network node; as well as Based on the report, the sounding reference signal configuration is received.

5. The device according to any one of claims 1 to 4, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: Reporting at least one index of one of the plurality of transmission and reception points, for which a quality metric of one of the plurality of transmission and reception points having the transmit power level is below a threshold associated with the quality metric.

6. The device according to claim 5, wherein: The quality metric comprises a reference signal received power.

7. The device according to any one of claims 5 to 6, wherein: The quality metric comprises a signal-to-noise ratio.

8. The device according to any one of claims 1 to 7, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The set is determined based on a range within which the user equipment is served using coherent joint transmissions from the plurality of transmission and reception points.

9. The device according to claim 8, wherein: The range is defined based on the first condition and the second condition; The first condition includes using as a first reference point for the range a path loss reference signal resource corresponding to a highest reference signal received power value within the set; as well as The second condition includes using a path loss reference signal resource corresponding to a lowest reference signal received power value within the set as a second reference point for the range.

10. The device according to claim 9, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The set is adjusted so that the first condition is satisfied for uplink data or reference signal or control information transmission from the user equipment to the transmission and reception points within the set.

11. The device according to any one of claims 9 to 10, wherein: For uplink data or reference signal or control information transmission from the user equipment to the transmission and reception points in the set, the first condition is met.

12. The device according to any one of claims 9 to 11, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The set is adjusted so that for the uplink data or reference signal or control information transmission from the user equipment to at least one of the transmission and reception points in the set, the second condition is not satisfied, and for the uplink data or reference signal or control information transmission from the user equipment to at least another of the transmission and reception points in the set, the second condition is satisfied.

13. The device according to any one of claims 9 to 12, wherein: For the uplink data or reference signal or control information transmission from the user equipment to at least one of the transmission and reception points in the set, the second condition is not satisfied, and for the uplink data or reference signal or control information transmission from the user equipment to at least another of the transmission and reception points in the set, the second condition is satisfied.

14. The device according to any one of claims 8 to 13, wherein: The range is defined using at least one automatic gain control saturation tolerance as a first reference point and a minimum signal-to-noise ratio as a second reference point.

15. The device according to claim 14, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The set is adjusted so that the uplink data or reference signal or control information transmission from the user equipment to at least one of the multiple transmission and reception points in the set exceeds the at least one automatic gain control saturation tolerance, and the uplink data or reference signal or control information transmission from the user equipment to at least another of the transmission and reception points in the set does not exceed the automatic gain control saturation tolerance.

16. The device according to any one of claims 14 to 15, wherein: The uplink data or reference signal or control information transmission from the user equipment to at least one of the transmission and reception points in the set exceeds the at least one automatic gain control saturation tolerance, and the uplink data or reference signal or control information transmission from the user equipment to at least another of the transmission and reception points in the set does not exceed the automatic gain control saturation tolerance.

17. The device according to any one of claims 14 to 16, wherein: Different automatic gain control saturation tolerance levels are used for different transmission points among the plurality of transmission and reception points.

18. The device according to claim 17, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: receiving the different automatic gain control saturation tolerance levels; and Based on the received different automatic gain control saturation tolerance levels, the set is adjusted for power control.

19. The device according to any one of claims 8 to 18, wherein: The range is defined based on the received power tolerance.

20. The device according to any one of claims 1 to 19, wherein: The transmit power level is determined to compensate for a plurality of path losses associated with the plurality of path loss reference points.

21. The device according to any one of claims 1 to 20, wherein: The transmit power level is configured for use in estimating an aggregate channel from the user equipment to the plurality of transmission and reception points.

22. The device according to any one of claims 1 to 21, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: determining path loss values ​​for the plurality of transmission and reception points using the plurality of path loss reference points; limiting the set to transmission and reception points having highest path loss values; as well as The transmit power level is adjusted to a minimum level at which the transmission and reception points in the set can receive transmissions from the user equipment with sufficient signal power.

23. The device according to any one of claims 1 to 22, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: receiving downlink signaling including information related to an automatic gain control saturation tolerance level; and The transmit power level is determined so that the automatic gain control saturation tolerance level is not exceeded during the uplink data or reference signal or control information transmission.

24. The device according to claim 23, wherein: The downlink signaling is in the form of "nominal power+R db", where R corresponds to the automatic gain control saturation tolerance level.

25. The device according to any one of claims 1 to 23, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: determining a root mean square of path losses associated with the plurality of path loss reference points; The transmit power level is determined using the determined RMS.

26. The device according to claim 25, wherein The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: A higher priority is assigned to transmission and reception points at an average distance from the user equipment relative to a priority assigned to transmission and reception points relatively far from the user equipment.

27. The device according to claim 26, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: Transmission and reception points that are relatively far from the user equipment are removed from the set.

28. An apparatus comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least: estimating an aggregate channel using a transmit power level associated with a sounding reference signal transmission for sounding a channel for a transmission and reception point within a set comprising a plurality of transmission and reception points; wherein the transmit power level is based on a joint metric of a plurality of path loss reference points according to one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with the plurality of transmission and reception points, wherein the plurality of transmission and reception points have the same or different physical cell identifiers; and The estimated aggregated channel is used to determine a downlink precoding matrix for coherent joint transmission.

29. The device according to claim 28, wherein The aggregated channel is estimated as an aggregated channel matrix.

30. The device according to claim 29, wherein: The downlink precoding matrix is ​​determined using the aggregated channel matrix.

31. The device according to any one of claims 28 to 30, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: A report of at least one index of the plurality of transmission and reception points is received, for which a quality metric of one of the plurality of transmission and reception points having the transmit power level is below a threshold associated with the quality metric.

32. The device according to claim 31, wherein The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: One of the plurality of transmission and reception points associated with the at least one index is removed from the set.

33. The device according to any one of claims 31 to 32, wherein: The quality metric comprises a reference signal received power.

34. The device according to any one of claims 31 to 33, wherein: The quality metric comprises a signal-to-noise ratio.

35. The device according to any one of claims 28 to 34, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: A sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission is sent.

36. The device according to claim 35, wherein The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The transmit power level is determined, the transmit power level being associated with the sounding reference signal resource transmission.

37. The device according to any one of claims 28 to 36, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: determining a set of factors to be applied to a channel matrix for the one or more reference signal resources associated with the plurality of transmission configuration indicator states; The factors in the factor set reflect the combined impact of the corresponding path losses and the corresponding automatic gain control levels of the multiple path loss reference points; Therein, an aggregated channel matrix of the aggregated channel is estimated as a combination of the channel matrices after the set of factors are applied to the channel matrices accordingly.

38. The device according to any one of claims 28 to 37, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: The set of transmission and reception points is determined based on a range within which user equipment is to be served using coherent joint transmissions from the plurality of transmission and reception points.

39. The apparatus of claim 38, wherein: The range is defined based on the first condition and the second condition; The first condition includes using as a first reference point for the range a path loss reference signal resource corresponding to a highest reference signal received power value within the set; as well as The second condition includes using a path loss reference signal resource corresponding to a lowest reference signal received power value within the set as a second reference point for the range.

40. The device according to any one of claims 28 to 39, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: receiving from a user equipment a report of respective measurements of respective channels of the plurality of transmission and reception points; as well as determining a sounding reference signal configuration for the user equipment based on the report; wherein the sounding reference signal configuration is configured to be used with the user equipment to send uplink data or reference signals or control information from the user equipment to the plurality of transmission and reception points in the set based on a transmission power level; as well as The sounding reference signal configuration is sent to the user equipment.

41. The device according to any one of claims 28 to 40, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: performing respective measurements of respective channels of the plurality of transmission and reception points; receiving, from a user equipment, a report for one or more subsets of the plurality of transmission and reception points based on respective measurements of respective channels of the plurality of transmission and reception points; determining a sounding reference signal configuration for the user equipment based on the report; wherein the sounding reference signal configuration is configured to be used with the user equipment to send uplink data or reference signals or control information from the user equipment to the plurality of transmission and reception points in the set based on a transmission power level; as well as The sounding reference signal configuration is sent to the user equipment.

42. A method comprising: receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining a plurality of path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers; determining a transmit power level for transmission of the sounding reference signal resource based on a joint metric of the plurality of path loss reference points to sound channels for the plurality of transmission and reception points; determining a set of transmission and reception points in the plurality of transmission and reception points based on the determined transmission power level; as well as Using the one or more sounding reference signal resources, uplink data or reference signals or control information are sent from the user equipment to the plurality of transmission and reception points in the set based on the determined transmit power level.

43. A method comprising: estimating an aggregate channel using a transmit power level associated with a sounding reference signal transmission for sounding a channel for a transmission and reception point within a set comprising a plurality of transmission and reception points; wherein the transmit power level is based on a joint metric of a plurality of path loss reference points according to one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with the plurality of transmission and reception points, wherein the plurality of transmission and reception points have the same or different physical cell identifiers; and The estimated aggregated channel is used to determine a downlink precoding matrix for coherent joint transmission.

44. A non-transitory program storage device readable by a machine, tangibly embodying a program of instructions executable with the machine for performing operations comprising: receiving a sounding reference signal configuration including one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; obtaining a plurality of path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers; determining a transmit power level for transmission of the sounding reference signal resource based on a joint metric of the plurality of path loss reference points to sound channels for the plurality of transmission and reception points; determining a set of transmission and reception points in the plurality of transmission and reception points based on the determined transmission power level; as well as Using the one or more sounding reference signal resources, uplink data or reference signals or control information are sent from the user equipment to the plurality of transmission and reception points in the set based on the determined transmit power level.

45. A non-transitory program storage device readable by a machine, tangibly embodying a program of instructions executable with the machine for performing operations comprising: estimating an aggregate channel using a transmit power level associated with a sounding reference signal transmission for sounding a channel for a transmission and reception point within a set comprising a plurality of transmission and reception points; wherein the transmit power level is based on a joint metric of a plurality of path loss reference points according to one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with the plurality of transmission and reception points, wherein the plurality of transmission and reception points have the same or different physical cell identifiers; and The estimated aggregated channel is used to determine a downlink precoding matrix for coherent joint transmission.

46. ​​An apparatus comprising: means for receiving a sounding reference signal configuration comprising one or more sounding reference signal resources and / or resource sets for sounding reference signal resource transmission; means for deriving a plurality of path loss reference points from the one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with a plurality of transmission and reception points having the same or different physical cell identifiers; means for determining a transmit power level for transmission of said sounding reference signal resource based on a joint metric of said plurality of path loss reference points to sound channels for said plurality of transmission and reception points; means for determining a set of transmission and reception points of the plurality of transmission and reception points based on the determined transmission power level; as well as Means for sending uplink data or reference signals or control information from a user equipment to the plurality of transmission and reception points in the set based on the determined transmit power level using the one or more sounding reference signal resources.

47. An apparatus comprising: means for estimating an aggregate channel using a transmit power level associated with a sounding reference signal transmission for sounding a channel for a transmission and reception point within a set comprising a plurality of transmission and reception points; wherein the transmit power level is based on a joint metric of a plurality of path loss reference points according to one or more reference signal resources, the one or more reference signal resources being associated with a plurality of transmission configuration indicator states, the plurality of transmission configuration indicator states being associated with the plurality of transmission and reception points, wherein the plurality of transmission and reception points have the same or different physical cell identifiers; and Means for determining a downlink precoding matrix for coherent joint transmission using the estimated aggregated channel.

48. The device according to any one of claims 1 to 27, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: receiving, using the user equipment, a set of path loss reference signals; and The path loss reference signal is measured using the user equipment.

49. The apparatus of claim 48, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: determining, using the user equipment, a subset of a path loss reference signal based on a metric; as well as The transmit power level of the sounding reference signal transmission is determined based on the determined subset using the user equipment.

50. The apparatus of claim 48, wherein: The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least: reporting, using the user equipment, a result of the measurement of the path loss reference signal; receiving, using the user equipment, a subset of a path loss reference signal from a network node; as well as A transmit power level for the sounding reference signal transmission is determined using the user equipment based on the received subset.

51. The apparatus of claim 50, wherein: The network node includes a gNB.

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