Method of sounding reference signal transmission associated with resources reported by user equipment

Abstract

The present invention relates to a method of sounding reference signal transmission associated with resources reported by user equipment. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a network, a configuration comprising associating N downlink reference signals with the network, the downlink reference signal reported to the network indicates to the network that the apparatus is capable of transmitting a sounding reference signal associated with the reported downlink reference signal; determining a maximum of N downlink reference signals to be reported based on at least one criterion; reporting a maximum of N downlink reference signals to the network; receiving a command for triggering the transmission of the sounding reference signal; and transmitting the maximum N sounding reference signals associated with the reported maximum N downlink reference signals, respectively, to the network.

Description

Technical Field

[0001] The present invention relates to a beam reporting process. Background Art

[0002] Beam management defines a set of functions that assists a user equipment (UE) in setting up the UE's receive and transmit (RX / TX) beams for downlink reception and uplink transmission, respectively. In 3GPP New Radio (NR), beam management for both downlink and uplink is network controlled, including triggering beam reports from the UE.

[0003] A new carrier frequency range of 7-20 GHz is planned to be introduced in the next generation (6G) networks. The operation of the new carrier frequency range can be considered as a hybrid of frequency range 1 (0-6 GHz) and frequency range 2 (24-71 GHz). Due to the possible use of the new frequency band, larger antenna arrays may be required to cope with the additional path loss and penetration loss compared to operation in the frequency bands below 6 GHz. The new frequency band may also enable the use of larger bandwidths compared to NR. In order to be able to effectively utilize the larger bandwidths and large antenna arrays, analog or hybrid digital-analog beamforming architectures may be viable options for UE implementations for the new frequency bands. When the UE operates using antenna arrays and analog beamforming, a combined beam management process for gNB and UE beam alignment is required. Summary of the invention

[0004] Now, an improved method and a technical device for implementing the method have been invented to alleviate the above-mentioned problems. Various aspects include a method, an apparatus and a non-transitory computer-readable medium including a computer program or a signal stored therein, which are characterized by what is described in the independent claims. Various details of the embodiments are disclosed in the dependent claims and the corresponding drawings and description.

[0005] The scope of protection sought for the various embodiments of the invention is defined by the independent claims. Embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, are to be construed as examples useful for understanding the various embodiments of the invention.

[0006] According to a first aspect, a device is provided, comprising: a component for receiving from a network a configuration comprising associating N downlink reference signals respectively with N sounding reference signals; a component for determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; a component for reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signal reported to the network indicates to the network that the device is capable of sending a sounding reference signal associated with the reported downlink reference signal; a component for receiving a command to trigger transmission of a sounding reference signal; and a component for sending to the network a maximum of N sounding reference signals respectively associated with the reported maximum of N downlink reference signals in response to receiving the command.

[0007] According to the second aspect, the device includes: at least one processor and at least one memory storing instructions, and the instructions, when executed by the at least one processor, cause the device to at least perform: receiving a configuration including associating N downlink reference signals with N sounding reference signals respectively from a network; determining a maximum of N downlink reference signals to be reported based on at least one criterion; reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the device is capable of sending a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger the transmission of the sounding reference signal; and in response to receiving the command, sending a maximum of N sounding reference signals associated with the reported maximum of N downlink reference signals to the network.

[0008] The method according to the third aspect includes: receiving a configuration from a network including associating N downlink reference signals with N sounding reference signals, respectively; determining a maximum of N downlink reference signals to be reported based on at least one criterion; reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signal reported to the network indicates to the network that a device is capable of sending a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger transmission of a sounding reference signal; and in response to receiving the command, sending a maximum of N sounding reference signals to the network, respectively associated with the reported maximum of N downlink reference signals.

[0009] According to the fourth aspect, the device includes: a component for determining N downlink reference signals to be reported by a user equipment for sounding reference signal transmission; a component for sending an indication to the user equipment to associate the N downlink reference signals with the N sounding reference signals respectively; a component for receiving a report of up to N downlink reference signals from the user equipment, wherein the reported downlink reference signal indicates to the network that the device is capable of sending a sounding reference signal associated with the reported downlink reference signal; a component for sending a command to trigger the transmission of the sounding reference signal to the user equipment; a component for receiving up to N sounding reference signals from the user equipment respectively associated with the reported up to N downlink reference signals; and a component for measuring and analyzing the received signals.

[0010] According to other aspects, a computer-readable storage medium includes code for use by an apparatus, which, when executed by a processor, causes the apparatus to perform the above-described method. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a more complete understanding of example embodiments, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 A schematic block diagram of an apparatus for combining a beam distribution apparatus according to an embodiment is shown;

[0013] Figure 2 schematically shows a layout of an apparatus according to an example embodiment;

[0014] Figure 3 A portion of an exemplary radio access network is shown;

[0015] Figure 4 An example of a radio beam alignment procedure between a gNB and a UE for both reception and transmission (Rx / Tx) is shown;

[0016] Figure 5 shows a signaling diagram between a UE and a network during an SRS procedure according to one embodiment;

[0017] Figure 6 A flow chart showing a beam reporting process according to one embodiment; and

[0018] Figure 7 A flow chart of a beam reporting process according to another embodiment is shown. DETAILED DESCRIPTION

[0019] Based on the above discussion, a beam reporting procedure that can achieve faster link switching and provide additional information to the network for scheduling would be of interest.

[0020] Suitable means and possible mechanisms for performing beam distribution are described in more detail below. Although the following focuses on 5G networks, the embodiments described further below are by no means limited to implementation in this network, but rather they are applicable to any network supporting beam distribution.

[0021] In this regard, first refer to Figure 1 and 2 ,in Figure 1 A schematic block diagram of an exemplary apparatus or electronic device 50 is shown, which may incorporate apparatus according to embodiments. Figure 2 The layout of the device according to an exemplary embodiment is shown. Figure 1 and 2 unit.

[0022] The electronic device 50 may be, for example, a mobile terminal or user equipment of a wireless communication system. The device 50 may include a housing 30 for housing and protecting the device. The device 50 may also include a display 32 and a keypad 34. Instead of a keypad, the user interface may be implemented as a virtual keypad or data input system as part of a touch-sensitive display.

[0023] The device may include a microphone 36 or any suitable audio input, which may be a digital or analog signal input. The device 50 may also include an audio output device, such as any of the following: headphones 38, speakers, or analog audio or digital audio output connections. The device 50 may also include a battery 40 (or the device may be powered by any suitable mobile energy device such as a solar cell, a fuel cell, or a clockwork generator). The device may also include a camera 42, which is capable of recording or capturing images and / or video. The device 50 may also include an infrared port 41, which is used for short-range line-of-sight communication with other devices. In other embodiments, the device 50 may also include any suitable short-range communication solution, such as a Bluetooth wireless connection or a USB / FireWire wired connection.

[0024] The device 50 may include a processor 56 for controlling the device 50. The processor 56 may be connected to a memory 58, which may store both user equipment and instructions to be implemented on the processor 56. The memory may be a random access memory (RAM) and / or a read-only memory (ROM). The memory may store instructions (e.g., computer-readable, computer-executable software) that, when executed by the processor, cause the device to perform various functions described herein. In some cases, the instructions may not be directly executable by the processor, but may cause the computer (e.g., when compiled and executed) to perform the functions described herein. The processor 56 may also be connected to a codec circuit 54, which is suitable for performing encoding and decoding of audio and / or video data, or assisting in encoding and decoding performed by the processor.

[0025] The device 50 may include a radio interface circuit 52 connected to the processor and adapted to generate wireless communication signals, for example to communicate with a cellular communication network, a wireless communication system or a wireless local area network. The device 50 may also include an antenna 44 connected to the radio interface circuit 52 to transmit radio frequency signals generated at the radio interface circuit 52 to other devices and to receive radio frequency signals from other devices.

[0026] In the following, different exemplary embodiments will be described using a radio access architecture based on Advanced Long Term Evolution (Advanced LTE, LTE-A) or New Radio (NR, 5G) as an example of an access architecture to which the embodiments may be applied, but the embodiments are not limited to such architectures. Those skilled in the art will appreciate that the embodiments may also be applied to other types of communication networks with suitable components by appropriately adjusting the parameters and processes. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, Mobile Ad Hoc Networks (MANETs), and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof.

[0027] Figure 3 An example of a simplified system architecture is depicted, which shows only some units and functional entities, all of which are logical units, the implementation of which may differ from what is shown. Figure 3 The connections shown in are logical connections; the actual physical connections may be different. It is obvious to those skilled in the art that the system typically also includes Figure 3 However, the embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solution to other communication systems having the necessary characteristics.

[0028] Figure 3 The example of FIG. 1 shows a portion of an exemplary radio access network.

[0029] Figure 3 User equipment 300 and 302 are shown, which are configured to be wirelessly connected to an access node (e.g., (e / g) NodeB) 304 providing the cell on one or more communication channels in the cell, where (e / g) NodeB represents an eNodeB or a gNodeB or a node capable of being both. The physical link from the user equipment to the (e / g) NodeB is called an uplink or a reverse link, and the physical link from the (e / g) NodeB to the user equipment is called a downlink or a forward link. It should be understood that the (e / g) NodeB or their functions can be implemented by using any node, host, server, or access point entity suitable for such purpose.

[0030] The communication system usually includes more than one (e / g)NodeB, in which case the (e / g)NodeB can also be configured to communicate with each other through wired or wireless links designed for this purpose. These links can be used for signaling purposes. (e / g)NodeB is a computing device that is configured to control the radio resources of the communication system coupled thereto. NodeB can also be referred to as a base station, an access point or any other type of interface device, including a relay station capable of operating in a wireless environment. (e / g)NodeB includes a transceiver or is coupled to a transceiver. From the transceiver of the (e / g)NodeB, a connection to an antenna unit is provided, which establishes a bidirectional radio link to a user equipment. The antenna unit may include multiple antennas or antenna elements. (e / g)NodeB is also connected to a core network 310 (CN or next generation core NGC). Depending on the system, the corresponding part on the CN side may be a service gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW, for providing a connection of a user equipment (UE) to an external packet data network) or a mobile management entity (MME), etc. The CN may include network entities or nodes which may be referred to as management entities. Examples of network entities include at least an Access and Mobility Management Function (AMF).

[0031] A user equipment (also referred to as user equipment (UE), user terminal, terminal device, wireless device, mobile station (MS), etc.) illustrates a type of apparatus for which resources on the air interface are allocated and specified, and thus any features described herein using user equipment can be implemented using corresponding network apparatus (e.g., relay nodes, eNBs, and gNBs). An example of such a relay node is a layer 3 relay (self-backhaul relay) toward a base station.

[0032] User equipment generally refers to a portable computing device including a wireless mobile communication device operating with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), mobile phones, devices using wireless modems (alarm or measurement devices, etc.), laptop and / or touch screen computers, tablet computers, game consoles, notebook computers, and multimedia devices. It should be understood that a user device can also be a device that almost exclusively has an uplink, an example of which is a camera or video camera that loads images or video clips to a network. A user device can also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which an object has the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction. Therefore, a user device can be an IoT device. A user device can also utilize a cloud. In some applications, a user device can include a small portable device (such as a watch, headset, or glasses) with a radio component, and the calculation is performed in the cloud. A user device (or in some embodiments, a layer 3 relay node) is configured to perform one or more user device functions. A user device may also be called a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, or user equipment (UE), to mention just a few names or devices.

[0033] The various techniques described herein may also be applied to cyber-physical systems (CPS) (systems of computing units that coordinate control of physical entities). CPS can enable the implementation and utilization of a large number of interconnected ICT devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems (where the physical system has inherent mobility) are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronics that are transported by humans or animals.

[0034] Additionally, although the apparatus has been described as a single entity, different units, processors and / or memory units may be implemented ( Figure 1 Not all are shown).

[0035] 5G enables the use of multiple-input multiple-output (MIMO) antennas, many more base stations or nodes than LTE (the so-called small cell concept), including macro sites operating in cooperation with smaller stations, and employing multiple radio technologies depending on service requirements, use cases and / or available spectrum. The access nodes of the radio network form transmit / receive (TX / Rx) points (TRPs), and UEs are expected to access a network of at least partially overlapping multiple TRPs, such as macro cells, small cells, pico cells, femto cells, remote radio heads, relay nodes, etc. The access nodes may be equipped with massive MIMO antennas (i.e., very large antenna arrays comprising, for example, hundreds of antenna elements), implemented in a single antenna panel or multiple antenna panels, capable of using multiple simultaneous radio beams to communicate with the UE. The UE may be equipped with a MIMO antenna with an antenna array comprising, for example, tens of antenna elements, implemented in a single antenna panel or multiple antenna panels. Therefore, the UE can use one beam to access one TRP, use multiple beams to access one TRP, use one (common) beam to access multiple TRPs, or use multiple beams to access multiple TRPs.

[0036] 4G / LTE networks support some multi-TRP schemes, but in 5G NR, the multi-TRP feature is enhanced, for example, by sending multiple control signals via multiple TRPs, which can improve link diversity gain. In addition, high carrier frequencies (such as mmWave) and massive MIMO antennas require new beam management processes for multi-TRP technology.

[0037] 5G mobile communications support a variety of use cases and related applications, including video streaming, augmented reality, different ways of data sharing and various forms of machine-type applications (such as (massive) machine-type communications (mMTC)), including vehicle safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, centimeter wave and millimeter wave, and can also be integrated with existing traditional radio access technologies (such as LTE). At least in the early stages, the integration with LTE can be implemented as a system in which macro coverage is provided by LTE and 5G radio interface access comes from small cells by aggregation to LTE. In other words, 5G plans to support both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz-centimeter wave, below 6GHz-centimeter wave-millimeter wave). One of the concepts considered to be used in 5G networks is network slicing, in which multiple independent and dedicated virtual subnets (network instances) can be created within the same infrastructure to run services with different requirements for latency, reliability, throughput and mobility.

[0038] The frequency bands for 5G NR are divided into two frequency ranges: Frequency Range 1 (FR1), which includes the frequency bands below 6 GHz (i.e., the bands traditionally used by previous standards), but also includes new bands that are extended to cover potential new spectrum offerings from 410 MHz to 7125 MHz; and Frequency Range 2 (FR2), which includes the frequency bands from 24.25 GHz to 52.6 GHz. FR2 thus includes frequency bands in the millimeter wave range, which require a slightly different approach in terms of radio resource management compared to frequency bands within FR1 due to their shorter range and higher available bandwidth.

[0039] The current architecture in LTE networks is completely distributed in the radio and completely centralized in the core network. Low-latency applications and services in 5G require content to be close to the radio, which leads to local grooming and multi-access edge computing (MEC). 5G enables analysis and knowledge generation to occur at the data source. This approach requires the use of resources that may not be continuously connected to the network, such as laptops, smartphones, tablets, and sensors. MEC provides a distributed computing environment for application and service hosting. It is also able to store and process content near cellular users for faster response times. Edge computing covers a variety of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer self-organizing networking and processing, and can also be classified as local cloud / fog computing and grid / net computing, dew computing, mobile edge computing, cloudlets, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (large-scale connectivity and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analysis, time-critical control, healthcare applications).

[0040] The communication system can also communicate with or utilize services provided by other networks (e.g., the public switched telephone network or the Internet) 312. The communication network can also support the use of cloud services, for example, at least a portion of the core network operations can be provided as a cloud service (this is in the Figure 3 The communication system may also include a central control entity or the like, providing facilities for different operator networks to collaborate, for example, in spectrum sharing.

[0041] Edge cloud can be introduced into the radio access network (RAN) by leveraging network function virtualization (NFV) and software defined networking (SDN). Using edge cloud can mean performing access node operations at least partially in a server, host or node operably coupled to a remote radio head or base station including radio components. It is also possible that the node operations will be distributed among multiple servers, nodes or hosts. Applying the cloudRAN architecture enables RAN real-time functions to be performed on the RAN side (in the distributed units DU) and non-real-time functions to be performed in a centralized manner (in the central unit CU 308).

[0042] It should also be understood that the division of labor between core network operations and base station operations may be different from that of LTE, or even non-existent. Some other technological advances that may be used are big data and all-IP, which can change the way networks are constructed and managed. 5G (or New Radio NR) networks are designed to support multiple hierarchical structures, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be understood that MEC can also be applied in 4G networks. gNB is the next generation Node B (or new Node B) that supports 5G networks (i.e., NR).

[0043] 5G can also utilize non-terrestrial nodes 306 (e.g., access nodes) to enhance or supplement the coverage of 5G services, for example, by providing backhaul, wireless access to wireless devices, service continuity for machine-to-machine (M2M) communications, service continuity for Internet of Things (IoT) devices, service continuity for onboard passengers, ensuring service availability for critical communications, and / or ensuring service availability for future railway / maritime / aviation communications. Non-terrestrial nodes can have a fixed position relative to the surface of the earth, or non-terrestrial nodes can be mobile non-terrestrial nodes that can move relative to the surface of the earth. Non-terrestrial nodes can include satellites and / or HAPS. Satellite communications can utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular giant constellations (systems in which hundreds of (nano) satellites are deployed). Each satellite in a giant constellation can cover multiple satellite-supporting network entities that create ground cells. Ground cells can be created by ground relay nodes 304, or by gNBs located on the ground or in satellites.

[0044] Those skilled in the art will appreciate that the system shown is only an example of a portion of a radio access system, and in practice, the system may include multiple (e / g)NodeBs, a user equipment may access multiple radio cells, and the system may also include other devices, such as physical layer relay nodes or other network elements, etc. At least one of the (e / g)NodeBs may be a home (e / g)NodeB. Additionally, in a geographical area of ​​a radio communication system, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. A radio cell may be a macro cell (or umbrella cell), which is a large cell, typically having a diameter of up to tens of kilometers, or a smaller cell, such as a micro cell, a femto cell or a pico cell. Figure 1 The (e / g)NodeB of a cell can provide any type of these cells. A cellular radio system can be implemented as a multi-layer network including multiple types of cells. Typically, in a multi-layer network, one access node provides one or more cells of one type, and therefore multiple (e / g)NodeBs are required to provide this network structure.

[0045] In order to meet the needs of improving the deployment and performance of communication systems, the concept of "plug and play" (e / g) NodeB is introduced. Generally, a network that can use "plug and play" (e / g) NodeB includes a home (e / g) NodeB (H(e / g) NodeB) and a home NodeB gateway or HNB-GW ( Figure 1 (not shown). An HNB gateway (HNB-GW), which is usually installed in an operator's network, can aggregate services from a large number of HNBs back to the core network.

[0046] The Radio Resource Control (RRC) protocol is used in various wireless communication systems to define the air interface between the UE and the base station (e.g., eNB / gNB). 3GPP specifies the protocol in TS 36.331 for LTE and TS 38.331 for 5G. As far as RRC is concerned, the UE can operate in idle mode or connected mode in LTE and 5G, where the radio resources available to the UE depend on the mode the UE is currently in. In 5G, the UE can also operate in inactive mode. In RRC idle mode, the UE has no connection for communication, but the UE is able to listen to paging messages. In RRC connected mode, the UE can operate in different states, such as CELL_DCH (dedicated channel), CELL_FACH (forward access channel), CELL_PCH (cell paging channel), and URA_PCH (URA paging channel). The UE can communicate with the eNB / gNB via various logical channels, such as broadcast control channel (BCCH), paging control channel (PCCH), common control channel (CCCH), dedicated control channel (DCCH), dedicated traffic channel (DTCH).

[0047] The transitions between states are controlled by the state machine of RRC. When the UE is powered on, it is in disconnected mode / idle mode. The UE can transition to RRC connected mode by initial attach or by connection establishment. If there is no activity from the UE for a short period of time, the eNB / gNB can suspend its session by moving to RRC inactive mode, and can resume its session by moving to RRC connected mode. The UE can move from RRC connected mode or from RRC inactive mode to RRC idle mode.

[0048] The actual user and control data from the network to the UE is sent via downlink physical channels. In 5G, the downlink physical channels include: Physical Downlink Control Channel (PDCCH), which carries the necessary downlink control information (DCI); Physical Downlink Shared Channel (PDSCH), which carries user data and user system information; and Physical Broadcast Channel (PBCH), which carries the necessary system information to enable the UE to access the 5G network.

[0049] User and control data from the UE to the network are sent via uplink physical channels. In 5G, the uplink physical channels include: Physical Uplink Control Channel (PUCCH), which is used for uplink control information, including HARQ feedback confirmation, scheduling requests, and downlink channel state information for link adaptation; Physical Uplink Shared Channel (PUSCH), which is used for uplink data transmission; and Physical Random Access Channel (PRACH), which is used by the UE to request connection establishment (called random access).

[0050] For 5G technology, one of the most important design goals, in addition to network resilience and flexibility, is to improve reliability and latency indicators.

[0051] Especially when considering UE operation in Frequency Range 2 (FR2; 24.25 GHz to 52.6 GHz) including the mmWave range, UE implementations are expected to have multiple antenna panels (multi-panel UE, MPUE) to perform beam steering within a large solid angle, aiming to maximize reliability.

[0052] Beam management defines a set of functions to assist the UE in setting up its receive and transmit (RX / TX) beams for downlink reception and uplink transmission, respectively. In NR, beam management for both downlink and uplink is network controlled, including triggering beam reports from the UE. The functions of beam management can be roughly divided into four groups:

[0053] 1. Beam indication

[0054] - Assist the UE to properly set its RX and TX beams for DL ​​reception and UL transmission, respectively.

[0055] 2. Beam acquisition, management and reporting

[0056] - Procedure for providing gNB knowledge about feasible DL and UL beams to the UE.

[0057] 3. Beam recovery

[0058] - For fast link reconfiguration against sudden blockages, i.e., fast realignment of gNB and UE beams.

[0059] 4. Beam tracking and refinement

[0060] - Set of procedures for refining gNB and UE side beams.

[0061] With regard to downlink beam management, and in particular for beam acquisition, measurement and reporting, support is provided within one or more TRPs of the serving cell. Figure 4 The following beam management processes P-1, P-2 and P-3 identified in:

[0062] a) P-1 is used to implement UE measurements on different TRP Tx beams to support TRP Tx beam / UE Rx beam selection

[0063] -For beamforming at the TRP, it usually includes intra-TRP / inter-TRP Tx beam scanning from different beam sets (shown using arrows). For beamforming at the UE, it usually includes UE Rx beam scanning from different beam sets. Figure 4In the example shown in Figure 1, beam number 3 is selected.

[0064] b) P-2 is used to implement UE measurements on different TRP Tx beams to possibly change the inter-TRP / intra-TRP Tx beam

[0065] - P-2 can be performed from a possibly smaller set of beams than P-1 for beam refinement. Note that P-2 can be a special case of P-1.

[0066] c) P-3 is used to enable UE measurements on the same TRP Tx beam to change the UE Rx beam if the UE uses beamforming. Figure 4 In the example, beam number 3 is selected on the TRP side, and beam number 2 is selected on the UE side.

[0067] Regarding downlink beam indication, a quasi co-location (QCL) indication function has been defined. The principle of receiving a specific physical signal or physical channel is that the UE is configured with or the UE implicitly determines a source / reference signal (RS) that the UE has previously received and measured, which defines how to set the RX beam for receiving the downlink (target) physical signal or channel to be received. In order to provide the UE with the QCL characteristics of the target signal (to be received), a transmission coordination indication (TCI) framework has been defined, using which the UE can be configured with a TCI state so as to provide the UE with a source reference signal (RS) for determining the QCL characteristics. Each TCI state includes one or two source RSs, which provide TypeA, TypeB, TypeC and / or TypeD parameters to the UE QCL. The parameters provided by different types are as follows:

[0068] -QCL-TypeA: {Doppler shift, Doppler spread, average delay, delay spread}

[0069] -QCL-TypeB: {Doppler shift, Doppler spread}

[0070] -QCL-TypeC: {Doppler shift, average delay}

[0071] -QCL-TypeD: {spatial Rx parameters}

[0072] In the uplink, the UE is provided with a parameter called spatial relation information, which provides the spatial source RS, based on which the UE determines the uplink transmit beam. The spatial source RS can be a DL RS (SSB or CSI-RS) or a UL RS (sounding reference signal SRS). For each PUCCH and SRS resource, the gNB explicitly provides the spatial source, while for PUSCH, an indirect indication is provided:

[0073] -PUSCH scheduled using DCI format 0_0, the spatial source is the same as the specific PUCCH resource

[0074] - PUSCH scheduled using DCI format 0_1, the spatial source is the same as the indicated SRS resource

[0075] o One SRS resource indicated in the codebook-based transmission scheme

[0076] o One or more SRS resources indicated in a non-codebook based transmission scheme

[0077] 3GPP Release 16 (Rel16) introduces the default spatial relationship for dedicated PUCCH / SRS (except for SRS with usage = "beamManagement" and SRS with usage = "nonCodeBook" and configured with associated CSI-RS), where if the spatial relationship is not configured in FR2, the UE determines the spatial source as follows:

[0078] - If CORESET is configured for CC, the spatial source is the TCI state of the CORESET with the lowest ID

[0079] / QCL assumption.

[0080] - If no CORESET is configured for a CC, the spatial source is the activated TCI state with the lowest ID that applies to the PDSCH in the active DL-BWP of the CC.

[0081] Rel16 also introduces the default spatial relationship for PUSCH scheduled by DCI format 0_0, where the UE determines the spatial source as follows:

[0082] - When there are no PUCCH resources configured for the active UL BWP CC:

[0083] oThe default spatial relationship is the TCI state / QCL assumption of the CORESET with the lowest ID.

[0084] oThe default path loss RS is the QCL-Type DRS of the same TCI state / QCL assumption of the CORESET with the lowest ID.

[0085] - When in FR2 and in RRC connected mode there are no PUCCH resources configured for the active UL BWP CC:

[0086] oThe default spatial relationship is the TCI state / QCL assumption of the CORESET with the lowest ID.

[0087] oThe default path loss RS is the QCL-Type DRS of the same TCI state / QCL assumption of the CORESET with the lowest ID.

[0088] Rel17 introduces a unified TCI framework, which means that the TCI states that have been used so far to provide QCL assumptions for the reception of DL signals and channels will also be used to provide spatial sources for the transmission of UL signals and channels to determine the UL TX spatial filter. In addition, the unified TCI framework defines the concept of indicated TCI states, which means that one or more (for example in the case of multiple TRPs) configured TCI states are indicated TCI states at one time. The indicated TCI state can be a joint DL and UL TCI state, or a separate DL and separate UL TCI state. The indicated TCI state provides QCL sources (DL) and spatial sources (UL) for downlink signals and channel sets and for uplink signals and channel sets, respectively. According to Rel17, there can be one indicated joint DL and UL TCI state, or one indicated DL TCI state and one indicated UL TCI state for the UE.

[0089] Rel18 further extends the unified TCI framework so that there can be multiple indicated DL and UL TCI states.

[0090] Beam reporting is providing the network with UE measurements of a set of (e.g. best / highest quality) DL RSs representing beam reference signals. That is, based on the beam reporting, the gNB / network decides the beam pair used for both downlink and uplink. The UE can be configured to report the L1-RSRP (Layer 1 Reference Signal Received Power) value or L1-SINR (Layer 1 Signal to Interference and Noise Ratio) value of the reported DL RS. The reporting can be periodic, semi-persistent or aperiodic reporting triggered by the gNB via a DCI command on the PDCCH.

[0091] According to one approach, beam reporting may include the transmission of a sounding reference signal. This may be performed, for example, in four phases. In the first phase, the gNB configures the UE for SRS. In this phase, the gNB determines the SRS configuration (e.g., SRS physical resources, usage, reporting period timing, etc.) and notifies the UE of the configuration via an RRC message (e.g., RRCSetup, RRCReconfiguration). The SRS configuration is provided by the gNB to the UE, and the SRS configuration may vary depending on the cell's conditions and service requirements.

[0092] In the second phase, the UE sends SRS to the gNB. SRS is a predefined signal with known characteristics at a specific time and frequency. The UE can send SRS periodically or aperiodically on the uplink (UL) channel as instructed by the gNB.

[0093] In the third phase, the gNB receives the SRS and measures and analyzes the received signal. The gNB estimates the channel state information (CSI) by comparing the received SRS with a known reference signal. The gNB evaluates various parameters such as path loss, propagation delay (phase delay), and received signal strength to understand the current radio environment and channel conditions between the gNB and the UE.

[0094] In the fourth phase, the gNB can take advantage of SRS. Once the gNB has estimated the channel state based on SRS, the gNB uses this information to optimize its resource allocation and scheduling decisions. This may involve adjusting transmission parameters (such as modulation and coding schemes) or selecting the most appropriate MIMO settings to enhance overall system capacity and improve user experience.

[0095] NR Rel-17 specification provides support for single-user DL PDSCH scheduling of up to 8 layers (i.e., rank 8). However, Rel-15 UL SRS resource configuration with antenna switching can only provide support for UEs equipped with 4 RX antenna ports. In other words, even if the UE is equipped with 8 RX antenna ports, only four of the eight antenna ports can be used for UL SRS sounding based on gNB-side DL CSI acquisition. Obviously, this leads to suboptimal use of the potential benefits of DL TX precoding as well as RX processing, thereby limiting system performance in terms of, for example, spectral efficiency and interference mitigation.

[0096] NR Rel-17 supports the following SRS time domain behaviors; periodic, semi-persistent, and aperiodic transmission. For semi-persistent SRS transmission, MAC-CE is used to activate and deactivate a set of one or more SRS resources for semi-persistence. When activated, the semi-persistent UL SRS resources are sent with the configured period and slot offset. Therefore, a more dynamic on / off control is achieved compared to periodic SRS resources configured only through RRC signaling.

[0097] In Rel-17, depending on the reported UE antenna switching capabilities, the UE may be configured with the higher layer parameter usage in SRS-ResourceSet set to "antennaSwitching", and depending on the indicated UE capabilities supportedSRS-TxPortSwitch, the UE may be configured with only one of the following configurations ("t1r2" for 1T2R; "t1r1-t1r2" for 1T=1R / 1T2R; "t2r4" for 2T4R; "t1r4" for 1T4R; "t1r6" for 1T6R; "t1r8" for 1T8R; "t2r6" for 2T6R; "t2r8" for 2T8R; "t4r8" for 4T8R; "t4r8" for 1T=1R / 1T2R / 1T2R); For T4R, it is "t1r1-t1r2-t1r4"; for 1T4R / 2T4R, it is "t1r4-t2r4"; for 1T=1R / 1T2R / 2T=2R / 2T4R, it is "t1r1-t1r2-t2r2-t2r4"; for 1T=1R / 1T2R / 2T=2R / 1T4R / 2T4R, it is "t1r1-t1r2-t2r2-t1r4-t2 "r4" for T=1R; "t1r1" for 2T=2R; "t2r2" for 1T=1R / 2T=2R; "t1r1-t2r2" for 4T=4R; or "t1r1-t2r2-t4r4" for 1T=1R / 2T=2R / 4T=4R), where T and R define the number of transmit antenna ports and receive antenna ports on the UE side, respectively. The indicated UE antenna switching capability "xTyR" corresponds to a UE capable of SRS transmission on "x" antenna ports on a total of "y" antennas, where "y" corresponds to all UE receive antennas or a subset of the UE receive antennas.

[0098] The UE is configured with a guard period of Y symbols during which the UE does not send any other signal in the case of sending the SRS resources of the set in the same slot. The guard period is between the SRS resources of the set. For two SRS resource sets with antenna switching in two consecutive slots, if the UE is able to send SRS in all symbols in one slot, there is a guard period of Y symbols between the last OFDM symbol occupied by the SRS resource set in the first slot and the first OFDM symbol occupied by the SRS resource set in the second slot.

[0099] For the inter-set guard period, if the interval between SRS resource sets is Y symbols, the UE does not send any other signal on any symbol of the interval.

[0100] - When SRS resources on all corresponding symbols before the gap and SIR resources on all corresponding symbols after the gap are discarded due to contention handling, the gap period is also discarded with the same priority and can be used for UL transmission.

[0101] The UE shall be expected to be configured with the same number of SRS ports for all SRS resources in an SRS resource set with the higher layer parameter usage set to "antennaSwitching".

[0102] For 1T2R, 1T4R or 2T4R or 1T6R or 1T8R, 2T6R, 2T8R, 4T8R, the UE shall not expect to be configured or triggered with multiple SRS resource sets with the higher layer parameter usage set to "antennaSwitching" in the same timeslot. For 1T=1R, 2T=2R or 4T=4R, the UE shall not expect to be configured or triggered with multiple SRS resource sets with the higher layer parameter usage set to "antennaSwitching" in the same symbol.

[0103] The Rel-17 specification defines how the antenna ports of UL SRS resources are configured with repetition and without SRS frequency hopping: when frequency hopping within the SRS resources in each time slot is not configured (R=Ns), each antenna port of the SRS resources in each time slot is mapped to the same set of subcarriers in the same PRB set in all Ns symbols, where R is the SRS repetition factor.

[0104] When frequency hopping within the SRS resource in each time slot is configured without repetition (R=1), each antenna port of the SRS resource in each time slot is mapped to a different set of subcarriers in each OFDM symbol according to the SRS frequency hopping parameters SRS B, SRS C and hopping b defined in Section 6.4.1.4 of TS 38.211, where the same transmission comb value is assumed for different subcarrier sets. When both frequency hopping and repetition within the SRS resource in each time slot are configured (Ns≥4, R≥2), each antenna port of the SRS resource in each time slot is mapped to the same set of subcarriers in each set of R adjacent OFDM symbols, and frequency hopping across the Ns, R sets is performed according to the SRS frequency hopping parameters SRS B, SRS C and hopping b, where Ns should be divisible by R.

[0105] RRC 38.331 defines the SRS resource set in srs-config as follows, and defines the SRS resource as follows:

[0106]

[0107]

[0108] 38.212 defines an SRS request as follows:

[0109]

[0110] Higher peak data rates for UL can play an important role in short-range applications (e.g., home entertainment, video monitoring / surveillance in industrial / healthcare / security, IAB) and other applications where device power / form factor / cost is not as stringent as traditional handheld devices. UL transmissions greater than 4Tx in both FR1 and FR2 help bridge the gap between DL and UL spectrum efficiency. Therefore, methods and / or signaling solutions need to be developed to overcome this issue for Rel-18 or later.

[0111] One of the objectives of Rel-18 NR MIMO Evo DL UL is to discuss and define how to provide specification support for simultaneous multi-panel UL transmission with 2 panels (STx2P), as shown below:

[0112] 1. Study and, where justified, specify UL DMRS, SRS, SRI and TPMI (including codebook) enhancements to enable 8Tx UL operation to support 4 and more layers per UE in the UL for CPE / FWA / vehicle / industrial equipment.

[0113] According to one method, a UE may be configured with a single UL SRS resource in an SRS resource set with usage as "codebook" or "antennaSwitching" for 8TX PUSCH with 8 ports and TDM factors s>1, s=2, where a subset of antenna ports is mapped onto m OFDM symbols (≥2) in a slot, where each of the m symbols / subsets includes 8 / s different antenna ports.

[0114] Rel-19 aims to study and specify UE initiated beam reporting that can enable faster link switching, provide additional information to the network for scheduling, and reduce overhead by enabling UE beam reporting when it is actually needed (to avoid periodic reporting and avoid wasted pinging by the gNB using aperiodic reporting).

[0115] The network (NW) provides the SRS transmission configuration using RRC signaling (and additionally, using MAC CE for changing the spatial relationship RS of the configured SRS). Triggering is further done using DCI messages. Typically, resource configuration is done based on DL RSRP reporting, where the UE is configured to report DL RS (+ e.g. RSRP), but this may not provide enough information or specific information for the network, such as how the UE sees potential UL candidate directions.

[0116] Hereinafter, an enhanced method for SRS reporting will be described in more detail according to various embodiments.

[0117] Figure 5 A signaling diagram of messages exchanged between a UE and a network during an SRS procedure according to one embodiment is shown. The network (e.g., a gNB) sends 502 a reporting configuration for UE-initiated SRS transmissions. In response to the configuration message, the UE sends 504 an L1 / L2 (Layer 1 / Layer 2) report of up to N (downlink) reference signals for SRS transmission. The network sends 506 an SRS trigger message to notify the UE to start the SRS transmission procedure. The SRS trigger message can be a specific message, or it can include an indication specific to triggering the transmission of at least one SRS associated with at least one UE-reported reference signal (DL RS). As a result of the reporting procedure (e.g., a downlink reference signal reporting procedure for SRS transmissions), the UE sends 508 one or more SRS transmissions associated with the reported resources.

[0118] Figure 6A flowchart of some steps related to the UE and the SRS process is shown. The UE receives 602 a report setting from the network. The report setting indicates to the UE configuration data for reporting one or more resources (DL RS) for at least one SRS transmission. The configuration data indicates that the UE reports one or more (up to N) DL RSs to the network, i.e., an indication of the number of downlink reference signals. In an alternative, the configuration data may indicate that the UE reports an SRS identifier that identifies an SRS resource or resource set. The reported SRS resource may be used as a reference for the triggered SRS transmission. N is a positive integer configured (e.g., RRC or MAC CE or DCI) or indicated by the network. The UE then reports 604 (up to) the configured / indicated number of DL RSs to the network. In other words, the UE reports different downlink reference signals so that the number is less than or equal to the indicated number N. When the UE receives 606 an SRS trigger command for SRS transmission from the network, the UE sends 608 one or more SRSs according to the SRS configuration. In one example, when the UE receives 606 an SRS trigger command for SRS transmission from the network, the UE sends 608 one or more SRS according to the SRS configuration and associates one or more transmitted SRS resources / resource sets with one or more reported reference signals (DLRS / DL resources).

[0119] Figure 7 A flow chart showing some steps of the network related to the SRS process. A network element (e.g., a gNB) determines 702 how many DL RSs the UE should report. Based on this determination, the network obtains 704 (up to) N DL RSs and sends 706 the N DL RSs to be reported by the UE. When the network receives 708 the N RSs reported by the UE, the network sends 710 an SRS trigger command to the UE. The network receives 712 one or more SRS transmissions from the UE. The network can then measure and analyze 714 the received signal and estimate the channel state information (CSI) by comparing the received SRS with a known reference signal. The network can also evaluate various parameters (e.g., path loss, propagation delay (phase delay), and received signal strength) to understand the current radio environment and channel conditions between the gNB and the UE.

[0120] In the following, some alternatives and other embodiments will be described.

[0121] According to one embodiment, a UE may be configured to trigger one or more SRS transmissions associated with resources reported by one or more UEs. In one example, reporting settings may be configured for the UE, where in the reporting settings, the UE is configured to report up to N (or equal to N) DL RSs to the network (e.g., BS / gNB). Once the UE has reported N RSs to the network, it is assumed / expected that the UE is capable of sending an SRS associated with at least one of the reported DL RSs upon receiving a downlink indication. In one example, the downlink indication may be a DCI message that includes a trigger or indication to send an SRS based on at least one of the reported resources. In some examples, the downlink indication may be a DCI message that includes an SRI (SRS resource / request indicator) field, where the value of the SRI may reference an SRS resource associated with the resources reported by the UE. The capability may also be determined based on the UE having reported N RSs to the network, i.e., the number of reported RSs may be an indication. In some examples, the reporting format may include N fields (for reporting up to N reference signals), and the UE may wish to report up to M (M < N) resources. In some examples, to report less than N (or M, where M < N) resources, the UE repeats the reported resource indicator value (e.g., if an SSBRI (SSB resource indicator) is reported, the UE may repeat the reported value of the SSBRI). In some examples, reporting the DL RS for SRS transmission may include a resource indicator and an associated / measured RSRP value. In some examples, if the UE reports less than N (e.g., M < N) resources, the UE may set one or more RSRP values of the resources to a low value or an invalid value for the reporting configuration. The UE may indicate the capability (e.g., using RRC signaling) within a time period after which the UE is capable of performing an SRS transmission associated with the resources reported by the UE.

[0122] Upon receiving an SRS trigger command (e.g., DCI) for an SRS transmission associated with the (DL) resources reported by the UE, the UE sends one or more SRSs according to the SRS configuration by using the reported one or more RSs as spatial relation RSs for the triggered SRS transmission.

[0123] According to one embodiment, the SRS resources for triggering SRS transmissions associated with the (DL) resources reported by the UE may be specifically configured for this operation (i.e., dedicated configuration / separate configuration).

[0124] Alternatively, the UE may be configured to use the RSs reported by the UE for at least one transmission to overwrite the current spatial relation RS for an existing SRS configuration / apply an alternative spatial relation RS for an existing SRS configuration (when the network indicates / triggers the transmission of at least one SRS).

[0125] According to one embodiment, the UE may indicate in a periodic / semi-persistent report that the report now includes event-triggered information instead of the configured information.

[0126] According to one embodiment, the report described herein may refer to L1 reporting on PUCCH or PUSCH, or it may refer to MAC CE reporting. L1 reporting or MAC CE may be used to perform UE reporting on DL RS to be used as reference / spatial relation for at least one SRS transmission.

[0127] According to one embodiment, the association of an SRS transmission with a DL RS / downlink resource / reference signal may include using the resource / reference as a spatial reference / relational RS for the SRS transmission. As an example (of a spatial relationship or spatial relationship RS), the spatial filter (e.g., beam / beam pattern / antenna pattern / radiation pattern / antenna configuration / panel) applied by the UE may be the same as the spatial filter used to receive the DL RS for the transmission of the associated SRS.

[0128] According to one embodiment, the DCI format (new field or new format) may include a field indicating a trigger command for SRS transmission associated with the resources reported by the UE. In one example, the field may be a new field in the DCI indicating (by an existing field, i.e., the SRI field) that the triggered SRS transmission will use the reported DL RS as the spatial relationship RS for the triggered transmission.

[0129] According to one embodiment, the UE may be configured with one or more SRS resource (set) configurations, each resource being associated with one or more reported DL RSs. As an example, the first reported DL RS is associated with the first configured SRS resource set, the second reported DL RS is associated with the second configured SRS resource set, and so on.

[0130] According to one embodiment, the DCI format for triggering the transmission of SRS associated with the resources reported by the UE can indicate the DL RS to be used as the spatial relationship RS by referencing the DL RS using an index pointing to the reporting order of the RS. Based on this indication, the UE applies the DL RS indicated by the DCI as the spatial relationship RS for the triggered SRS. This can be signaling in the form of a bitmap, that is, the bit position in the bitmap refers to the index of the reported resource. For example, the first bit refers to the first reported resource, the second bit refers to the second reported resource, and so on. This may allow triggering of SRS for one or more resources.

[0131] Alternatively, the bit field may include values ​​pointing to reported indices. For example, a first value ("00") points to the first resource index in the report, a second value "01" points to the second reported resource index, and so on.

[0132] According to one embodiment, if the DCI triggers multiple SRS transmissions, the DL RS reported by the UE is mapped to the spatial relationship RS for the SRS in ascending order of the SRS resource set ID and the RS indicated by the bit position. In one embodiment, the UE may be configured with one or more SRS resource set configurations, each resource being associated with one or more reported DL RSs. As an example, the first reported DL RS is associated with the first configured SRS resource set, and the second reported DL RS is associated with the second configured SRS resource set.

[0133] In one embodiment, a field in a downlink message (e.g., DCI) may indicate to the UE to trigger a measurement and reporting (e.g., non-periodic) event so that the UE reports resources for SRS transmission. The UE may select up to N reported resources, for example, based on DL RS RSRP, uplink information (e.g., MPE (maximum allowed emission) status, i.e., whether the UE is required to reduce the power of UL transmission).

[0134] In one embodiment, the UE may be configured to trigger an indication (eg, SR) that an event has occurred, the event including an indication that the UE prefers to report at least one candidate DL RS for SRS transmission.

[0135] In one embodiment, the UE may provide an event-triggered report for the candidate SRS spatial relationship RS in the form of a MAC CE.

[0136] In another embodiment, the mapping / association of the DL RS reported by the UE may be mapped according to, for example, the following example manner, or may be configured to be mapped according to, for example, the following example manner.

[0137] In one embodiment, each configured UL SRS resource set is assumed to be associated with one UE TX antenna panel at the UE side.

[0138] In one example, the spatial relationship RS is for an SRS resource in a resource set.

[0139] In one embodiment, the spatial relation RS is for a (single) SRS resource in an SRS resource set. That is, if two spatial relation RSs are used, they refer to SRS resources in different sets.

[0140] In one embodiment, a reporting setting for DL ​​RS for SRS transmission may be configured for multiple resource sets, where the resource sets may be mapped to CORESETpoolindex and / or first or second indicated TCI states (i.e., each TRP in a multi-TRP (mTRP) scenario). In this setting, the UE determines to report at least one resource from a first resource set and at least one resource from a second resource set. The UE considers the resources of the resource sets to map to different TRPs.

[0141] In one embodiment, the UE may be configured to trigger event-based reporting of up to N downlink reference signals and / or select up to N downlink reference signals based on at least one criterion or condition. As an example, the criterion or condition for triggering event-based reporting and / or selecting downlink reference signals for reporting may be based on an observed measurement or an uplink state determined based on a DL RS, or based on the UE having performed at least one estimation (e.g., path loss) or measurement using at least one DL RS selected for reporting. As an example, the criterion or condition for triggering event-based reporting and / or selecting downlink reference signals for reporting may be based on an MPE state (i.e., a condition based on power reduction). In another example, the criterion or condition for triggering event-based reporting and / or selecting downlink reference signals for reporting may be based on RSRP measurement. In one example, the criterion based on RSRP measurement may be the difference between a reference DL RS (e.g., a DL RS currently used as a spatial relationship for UL transmission) and a measured DL RS. In another example, the UE may determine to report a DL RS suitable for a spatial relationship for SRS transmission based on DL RS quality (e.g., RSRP level). In another example, the criteria or conditions for triggering event-based reporting and / or selecting a downlink reference signal for reporting may be based on a path loss measurement state. As an example, if the UE has performed path loss measurements on a DL RS, the UE may select an RS for reporting or trigger an event as described herein. Any of the above criteria may be used as a single criterion or in combination with more of the other criteria described.

[0142] In one embodiment, the UE may determine the reported resources and / or events based on the MPE status observed for the resources in the resource set.The UE determines to report DL RSs that are exempt from MPE restrictions, i.e., resources with no maximum power backoff applied or with a maximum power backoff less than a threshold.

[0143] The UE may be programmed to perform event triggering of the reporting order based on the MPE status observed on the RS associated with the current UL transmission.

[0144] If the power backoff to be applied for the current UL transmission on the first or second indicated TCI state is above a threshold (eg, if above , or X dB backoff is to be applied), the UE triggers event based reporting.

[0145] The UE may be programmed to perform event triggering for reporting based on the measured RSRP difference relative to the current DL RS used as a spatial relationship for the first or second configured uplink transmission (the first and second transmissions in mTRP, only the first transmission in single TRP). As an example, whether at least one measured RSRP value is higher for a DL RS that is not currently used as a spatial relationship for UL transmission.

[0146] The UE may be programmed to perform event triggering of reporting based on the measured RSRP value (ie, the N DL RSs of the UE with the highest measured RSRP).

[0147] The UE may be programmed to perform reporting (or event-triggered reporting) of a DL RS based on whether a path loss measurement has been made for the measured DL RS.

[0148] In one embodiment, if the UE determines that at least one DL RS can be detected / received on the primary antenna panel and the primary antenna panel is not currently configured for UL transmission, the UE may determine a trigger event to report the DL RS for SRS transmission. Alternatively, if the primary antenna panel detects a DL RS of DLRS_RSRP_primary+offset>DLRS_RSRP_secondary, the UE may determine to trigger an event-based report to report the DL RS for SRS transmission. The UE sets the offset to a value specific to the radiated power capability imbalance between the secondary / primary panels, DLRS_RSRP_secondary being the RSRP value of the DL RS received using the secondary panel and being the current spatial relationship RS for UL transmission. In one example, the offset value may be expressed in dB.

[0149] If there are multiple panels at the UE with different capabilities of generating / transmitting / radiating power, the UE is considered to have a primary antenna panel. For example, the primary antenna panel is capable of transmitting 4,5 dB more power on UL transmissions.

[0150] In one embodiment, the UE may determine to report DL RS resources (candidates for SRS transmission) mapped to (associated to) different antenna panels at the UE side.

[0151] As an example, the UE determines to select to report the DL RS resources in a manner that the first reported DL RS is mapped to the first antenna panel, the second reported DL RS is mapped to the second antenna panel, etc. In other words, the UE reports the downlink reference signals in a manner that the order of the reported downlink reference signals corresponds to the order of the antenna panels.

[0152] According to one aspect, an apparatus (e.g., a UE) includes: a component for receiving from a network a configuration including associating N downlink reference signals with N sounding reference signals, respectively; a component for determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; a component for reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signal reported to the network indicates to the network that the apparatus is capable of sending a sounding reference signal associated with the reported downlink reference signal; a component for receiving a command to trigger transmission of a sounding reference signal; and a component for sending to the network, in response to receiving the command, a maximum of N sounding reference signals associated with the reported maximum of N downlink reference signals, respectively.

[0153] According to one embodiment, the apparatus may include means for determining a maximum allowed transmission state for resources in a set of resources.

[0154] According to one embodiment, the means for reporting is configured to report downlink reference signals for which no maximum power backoff is applied or the applied maximum power backoff is less than a first threshold.

[0155] According to one embodiment, the apparatus is configured to perform event triggering of the reporting order based on a maximum allowed transmission state observed on a reference signal associated with a current uplink transmission.

[0156] According to one embodiment, the component for receiving the configuration is configured to: receive at least a first transmission coordination indication state or a second transmission coordination indication state, wherein the device is configured to: trigger an event-based report if the power backoff to be applied for the current uplink transmission in the indicated first transmission coordination indication state or the indicated second transmission coordination indication state is higher than a second threshold.

[0157] According to one embodiment, the apparatus may include: a component for measuring a reference signal received power; and a component for comparing the reference signal received power of a current downlink reference signal with another configured downlink reference signal.

[0158] According to one embodiment, the apparatus is configured to trigger event-based reporting based on the measured reference signal received power value.

[0159] According to one embodiment, the apparatus is configured to trigger event-based reporting based on whether a path loss measurement has been performed for the measured downlink reference signal.

[0160] According to one embodiment, the device includes at least a main antenna panel and a secondary antenna panel; wherein the device is configured to trigger an event-based report based on determining that at least one downlink reference signal can be detected or received on the main antenna panel and the main antenna panel is not currently configured for uplink transmission.

[0161] According to one embodiment, the device includes at least a main antenna panel and a secondary antenna panel, wherein the device is configured to trigger an event-based report if the difference between the reference signal received power of the downlink reference signal received by the main antenna panel and the reference signal received power of the downlink reference signal received by the secondary antenna panel is higher than an offset value.

[0162] According to one embodiment, the apparatus comprises a plurality of antenna panels, wherein different downlink reference signals are mapped to respective different antenna panels of the plurality of antenna panels.

[0163] According to one embodiment, the apparatus is configured to report downlink reference signals in such a way that the order of the reported downlink reference signals corresponds to the order of the antenna panels.

[0164] The term "component" as used in the specification and claims may refer to one or more individual units configured to perform the corresponding one or more referenced functions, or it may refer to multiple units that perform one or more such functions. In addition, multiple functions referenced in the claims may be performed by the same individual component or the same combination of components. For example, one or more such functions may be performed in a device by a processor executing instructions stored in a memory of the device.

[0165] According to another aspect, an apparatus includes at least one processor and at least one memory storing instructions (e.g., computer-readable, computer-executable software), which instructions, when executed by the at least one processor, cause the apparatus to at least perform: receiving from a network a configuration including associating N downlink reference signals with N sounding reference signals, respectively; determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the apparatus is capable of sending a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger transmission of a sounding reference signal; and in response to receiving the command, sending to the network a maximum of N sounding reference signals associated with the reported maximum of N downlink reference signals, respectively.

[0166] Such means may include, for example Figure 1-3 Functional units disclosed in any one of the for implementing the embodiments.

[0167] Another aspect relates to a computer program product stored on a non-temporary storage medium, comprising computer program code, which, when executed by at least one processor, causes an apparatus to at least perform: receiving from a network a configuration comprising associating N downlink reference signals with N sounding reference signals, respectively; determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; reporting a maximum of N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the apparatus is capable of sending a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger transmission of a sounding reference signal; and in response to receiving the command, sending to the network a maximum of N sounding reference signals associated with the reported maximum of N downlink reference signals, respectively.

[0168] In general, various embodiments of the present invention may be implemented in hardware or dedicated circuits or any combination thereof. Although various aspects of the present invention may be shown and described as block diagrams or using some other graphical representation, it is understood that, as non-limiting examples, these blocks, devices, systems, techniques or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general purpose hardware or processors or other computing devices, or some combination thereof.

[0169] Embodiments of the present invention may be implemented in various components such as integrated circuit modules. Generally speaking, the design of integrated circuits is a highly automated process. Complex and powerful software tools can be used to convert a logic level design into a semiconductor circuit design that can be etched and formed on a semiconductor substrate.

[0170] Programs, such as those provided by Synopsys, Inc. of Mountain View, Calif., and Cadence Design of San Jose, Calif., use well-established design rules and a library of pre-stored design blocks to automatically route conductors and position components on a semiconductor chip. Once the design of a semiconductor circuit has been completed, the resulting design in a standardized electronic format (e.g., Opus, GDSII, etc.) can be sent to a semiconductor manufacturing facility or "fab" for fabrication.

[0171] The above description is provided by way of exemplary and non-limiting examples, i.e., a comprehensive and informative description of exemplary embodiments of the present invention. However, when read in conjunction with the accompanying drawings and the accompanying examples, many modifications and variations may become apparent to those skilled in the relevant art in view of the above description. However, all of these and similar modifications to the teachings of the present invention still fall within the scope of the present invention.

Claims

1. A device comprising: means for receiving from a network a configuration comprising associating N downlink reference signals with N sounding reference signals, respectively; means for determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; means for reporting up to N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the apparatus is capable of transmitting a sounding reference signal associated with the reported downlink reference signal; means for receiving a command to trigger transmission of a sounding reference signal; and means for sending, in response to receiving the command, to the network up to N sounding reference signals respectively associated with the reported up to N downlink reference signals.

2. The device according to claim 1, comprising: Means for determining a maximum allowed transmit state for resources in a set of resources.

3. The device according to claim 2, wherein: The means for reporting is configured to report downlink reference signals for which no maximum power backoff is applied or the applied maximum power backoff is less than a first threshold.

4. The apparatus according to claim 2 or 3, configured to perform event triggering of the reporting order based on a maximum allowed transmission state observed on a reference signal associated with a current uplink transmission.

5. The device according to claim 4, wherein: The component for receiving the configuration is configured to: receive at least the first transmission coordination indication state or the second transmission coordination indication state, The apparatus is configured to trigger an event-based report if the power backoff to be applied for the current uplink transmission in the indicated first transmission coordination indication state or the indicated second transmission coordination indication state is higher than a second threshold.

6. The device according to any one of claims 1 to 3 or 5, comprising: A component for measuring a reference signal received power; as well as A means for comparing a reference signal received power of a current downlink reference signal with another configured downlink reference signal.

7. The device according to claim 6, wherein: The apparatus is configured to trigger event-based reporting based on the measured reference signal received power value.

8. The apparatus according to any one of claims 1 to 3 or 5, 7, is configured to trigger event-based reporting based on whether path loss measurement has been performed for the measured downlink reference signal.

9. The device according to any one of claims 1 to 3 or 5 and 7, wherein: The device comprises at least a primary antenna panel and an auxiliary antenna panel; The apparatus is configured to trigger event-based reporting based on determining that at least one downlink reference signal can be detected or received on the primary antenna panel and the primary antenna panel is not currently configured for uplink transmission.

10. The device according to any one of claims 1 to 3 or 5 and 7, wherein: The device comprises at least a primary antenna panel and an auxiliary antenna panel; The device is configured to trigger an event-based report if the difference between the reference signal received power of the downlink reference signal received by the primary antenna panel and the reference signal received power of the downlink reference signal received by the secondary antenna panel is higher than an offset value.

11. The device according to any one of claims 1 to 3 or 5 and 7, wherein: The apparatus includes a plurality of antenna panels; Different downlink reference signals are mapped to corresponding different antenna panels among the multiple antenna panels.

12. The device according to claim 11, wherein The apparatus is configured to report the downlink reference signals in a manner such that an order of the reported downlink reference signals corresponds to an order of the antenna panels.

13. A method comprising: receiving, from a network, a configuration comprising associating N downlink reference signals with N sounding reference signals, respectively; determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; reporting up to N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the device is capable of sending a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger transmission of a sounding reference signal; and In response to receiving the command, up to N sounding reference signals respectively associated with the reported up to N downlink reference signals are sent to the network.

14. An apparatus comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: receiving, from a network, a configuration comprising associating N downlink reference signals with N sounding reference signals, respectively; determining, based on at least one criterion, a maximum of N downlink reference signals to be reported; reporting up to N downlink reference signals to the network, wherein the downlink reference signals reported to the network indicate to the network that the apparatus is capable of transmitting a sounding reference signal associated with the reported downlink reference signal; receiving a command to trigger transmission of a sounding reference signal; and In response to receiving the command, up to N sounding reference signals respectively associated with the reported up to N downlink reference signals are sent to the network.

15. The device according to claim 14, wherein: Execution of the instructions stored in the at least one memory by the at least one processor causes the apparatus to at least perform: A maximum allowed transmit state for resources in a set of resources is determined.

16. The device according to claim 15, wherein: Execution of the instructions stored in the at least one memory by the at least one processor causes the apparatus to report downlink reference signals for which no maximum power backoff is applied or the applied maximum power backoff is less than a first threshold.

17. The device according to claim 15 or 16, wherein: Execution of the instructions stored in the at least one memory by the at least one processor causes the apparatus to: perform event triggering of a reporting order based on a maximum allowed transmission state observed on a reference signal associated with a current uplink transmission.

18. The device according to claim 17, wherein: Execution of the instructions stored in the at least one memory by the at least one processor causes the apparatus to: receiving at least one of a first transmission coordination indication state or a second transmission coordination indication state, If the power backoff to be applied for the current uplink transmission in at least one of the indicated first transmission coordination indication state or the indicated second transmission coordination indication state is above a second threshold, event based reporting is triggered.

19. The device according to any one of claims 14 to 16 or 18, wherein The apparatus comprises at least a primary antenna panel and a secondary antenna panel, wherein the instructions stored in the at least one memory are executed by the at least one processor so that the apparatus: Event-based reporting is triggered based on a determination that at least one downlink reference signal can be detected or received on the primary antenna panel and the primary antenna panel is not currently configured for uplink transmission.

20. The device according to any one of claims 14 to 16 or 18, wherein The apparatus comprises at least a primary antenna panel and a secondary antenna panel, wherein the instructions stored in the at least one memory are executed by the at least one processor so that the apparatus: If a difference between a reference signal received power of a downlink reference signal received by the primary antenna panel and a reference signal received power of a downlink reference signal received by the secondary antenna panel is higher than an offset value, an event based report is triggered.

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