Apparatus and methods for signaling quasi co-location updates with aperiodic reference signals

Abstract

This disclosure relates to techniques for signaling a quasi co-location (QCL) update in a wireless communication system. A network or base station can indicate to a UE to change the spatial relationship for transmission / reception. The base station can provide an aperiodic reference signal for the UE to use for beam tracking according to the new spatial relationship. Optionally, the base station can also provide an aperiodic reference signal for time, frequency, and / or phase tracking. Thus, the network can configure the UE to change to the new spatial relationship and use the aperiodic reference signals to quickly complete the initial tracking operations.

Description

TECHNICAL FIELD

[0001] This application relates to wireless communications, including to a quasi co-location (QCL) update procedure involving base stations and network elements in a wireless communication system. BACKGROUND

[0002] The use of wireless communication systems is increasing rapidly. Additionally, wireless communication technology has evolved from only voice communication to also include transmission of data such as Internet and multimedia content.

[0003] Mobile electronic devices can take the form of smartphones or tablets that users typically carry. Wearable devices, also known as accessory devices, are a newer form of mobile electronic device, one example being a smartwatch. Additionally, low-cost, low-complexity wireless devices intended for static or nomadic deployment are also increasing rapidly as part of the development of the "Internet of Things." In other words, the range of complexity, capability, traffic patterns, and other characteristics of desired devices is increasingly wide. Generally, it is desirable to recognize and provide improved support for a wide range of desired wireless communication characteristics. Accordingly, improvements in the art are desirable. SUMMARY

[0004] Embodiments of systems, apparatus, and methods, among other things, for performing a radio resource control connection procedure for a remote wireless device in a wireless communication system are presented herein.

[0005] As noted above, the number of use cases for wireless networks that communicate with different kinds of wireless devices having a wide range of capabilities and use expectations is increasing. One direction of expansion for possible use cases supported by wireless communication technology can include an increase in the use of beamforming. Wireless networks can update spatial relationships (e.g., beams) used to communicate with wireless devices from time to time. Changing to a new beam can include a delay.

[0006] Accordingly, techniques described herein include techniques for a network to schedule aperiodic reference signals in association with a spatial relationship update in order to, for example, expedite the update. For example, the network can trigger one or more aperiodic reference signal sets (using the new spatial relationship) for a wireless device to use for beam selection and synchronization among various possibilities. The aperiodic reference signals can be transmitted shortly after the indication of the new spatial relationship. For example, the aperiodic reference signals can be transmitted before the periodic reference signals.

[0007] The techniques described herein can be implemented in and / or used with a number of different types of devices, including but not limited to mobile telephones (e.g., iPhone TM , Android TM -based phones), tablet computers (e.g., iPad TM, Samsung Galaxy TM , portable gaming devices (e.g., Nintendo DS TM , PlayStation Portable TM , Gameboy Advance TM , iPhone TM ), wearable devices (e.g., smartwatch, smart glasses), laptop computers, PDAs, portable Internet devices, music players, data storage devices, other handheld devices, vehicles, cars, unmanned aerial vehicles (e.g., drones) and unmanned aerial controllers, other cellular network infrastructure equipment, servers, and various other computing devices.

[0008] This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are only examples and should not be employed to limit the scope or spirit of the subject matter described herein. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following DETAILED DESCRIPTION, Figures, and Claims. BRIEF DESCRIPTION OF DRAWINGS

[0009] A better understanding of the present subject matter can be obtained when the following detailed description of the embodiments is considered in conjunction with the drawings.

[0010] Figure 1 An exemplary wireless communication system including an accessory device is shown in accordance with some embodiments;

[0011] Figure 2 An exemplary wireless communication system in which two wireless devices are capable of direct device-to-device communication is shown in accordance with some embodiments;

[0012] Figure 3 is a block diagram illustrating an example wireless device in accordance with some embodiments;

[0013] Figure 4 is a block diagram illustrating an exemplary base station in accordance with some embodiments;

[0014] Figure 5 is a communication flow diagram illustrating an exemplary method for performing a QCL update in a wireless communication system in accordance with some embodiments;

[0015] Figures 6 to 8 Aspects of update indication and related signaling between a UE and a base station are shown in accordance with some embodiments; and

[0016] Figure 9 An exemplary data structure for a transmission control indicator is shown in accordance with some embodiments.

[0017] While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter defined by the appended claims. DETAILED DESCRIPTION

[0018] Acronyms and Abbreviations

[0019] The following acronyms and abbreviations are used throughout this disclosure:

[0020] 3GPP: Third Generation Partnership Project

[0021] 3GPP2: Third Generation Partnership Project 2

[0022] GSM: Global System for Mobile Communications

[0023] UMTS: Universal Mobile Telecommunications System

[0024] LTE: Long Term Evolution

[0025] IoT: Internet of Things

[0026] QCL: Quasi Co-Location

[0027] TCI: Transmission Configuration Indicator

[0028] RRC: Radio Resource Control

[0029] MAC: Medium Access Control

[0030] CE: Control Element

[0031] Tx: Transmit (or Transmission)

[0032] Rx: Receive (or Reception)

[0033] RS: Reference Signal

[0034] CSI: Channel State Information

[0035] Terminology

[0036] The following are definitions of terms used in this disclosure:

[0037] Memory Medium - any of various types of memory devices or storage devices. The term "memory medium" is intended to include a single memory device, such as one of the types listed above, or multiple memory devices. Further, the memory medium can include a computer-readable medium, a non-transitory computer-readable medium, or a non-transitory computer-readable storage medium. The terms "computer-readable medium" and "computer-readable storage medium" are used interchangeably herein. The memory medium can also include a single memory device, or multiple memory devices, and can also include a single computer-readable medium, or multiple computer-readable media. The memory medium can be transportable media, such as a compact disc (CD), a DVD, a Blu-ray Disc, a flash drive, a memory card, a magnetic tape, or other non-transitory computer-readable medium. The memory medium can also be non-transportable media, such as a hard disk drive, a random access memory (RAM), a dynamic RAM (DRAM), a static RAM (SRAM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable PROM (EEPROM), a magnetic or optical card, any other suitable type of memory device, or any combination thereof. The memory medium can also include a computer-readable medium that is located in a first computer system, or a second computer system that is connected to the first computer system by a network, such as the Internet. The memory medium can store or include a program that is executable by one or more processors of the computer system. The memory medium can store or include a program that is executable by one or more processors of the computer system.

[0038] Carrier Medium - a memory medium, as described above, and a physical transmission medium, such as a bus, network, and / or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

[0039] Programmable Hardware Element - includes various hardware devices comprising multiple programmable function blocks connected via a programmable interconnect. Examples

[0040] Computer System - various types of computing systems or processing systems including a personal computer system (PC), a mainframe computer system, a workstation, a network appliance, an internet appliance, a personal digital assistant (PDA), a television system, a grid computing system, or other device or combinations of devices. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0041] User Equipment (UE) (or "UE Device") - any of various types of computer systems or devices that a mobile or portable and that performs wireless communications. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone, other TM , Android TMphones (e.g., Apple iPhone®), tablets (e.g., Apple iPad®), portable gaming devices (e.g., Nintendo DS®, Sony PlayStation Portable®, Sony PSP®), cameras, wearable devices, computers, laptop computers, etc. TM TM TM TM TM TM In general, the term “UE” or “UE device” can be broadly defined to encompass any electronic, computing, and / or telecommunications device (or combination of devices) that a user can use to establish a wired or wireless communication with another device. A UE can be located in a stationary or fixed location or can be movable or portable. A UE can also be a personal computing device that is carried by a user.

[0042] Wireless device - any of various types of computer systems or devices that performs wireless communication. A wireless device can be portable (or mobile) or can be stationary or fixed at a location. A UE is an example of a wireless device.

[0043] Communication device - any of various types of computer systems or devices that performs communication, which can be wired or wireless. A communication device can be portable (or mobile) or can be stationary or fixed at a location. A wireless device is an example of a communication device. A UE is another example of a communication device.

[0044] Base station - the term “base station” has the full breadth of its ordinary meaning and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless communication system.

[0045] ​​​​​Link budget constrained - includes the full range of its ordinary meaning and at least includes a characteristic of a wireless device (e.g., a UE) that exhibits limited communication capabilities or limited power relative to devices that are not link budget constrained or relative to devices for which a radio access technology (RAT) standard has been developed. A link budget constrained wireless device can suffer from relatively limited reception and / or transmission capabilities, which can be due to one or more factors such as device design, device size, battery size, antenna size or design, transmission power, reception power, current transmission medium conditions, and / or other factors. Such a device can be referred to herein as a "link budget constrained" (or "link budget constrained") device. A device can be inherently link budget constrained due to its size, battery power, and / or transmission / reception power. For example, a smart watch communicating with a base station over LTE or LTE-A can be inherently link budget constrained due to its reduced transmission / reception power and / or reduced antenna. Wearable devices such as smart watches are generally link budget constrained devices. Alternatively, a device can not be inherently link budget constrained, e.g., can have sufficient size, battery power, and / or transmission / reception power for normal communication over LTE or LTE-A, but can be temporarily link budget constrained due to current communication conditions, e.g., a smart phone at the edge of a cell, etc. Note that the term "link budget constrained" includes or encompasses power limited, and thus a link constrained device can be considered a link budget constrained device.

[0046] Processing element (or processor) - refers to various elements or combinations of elements that are capable of performing a function of a device, such as a user equipment device or a cellular network device. Processing elements can include, for example, processor(s) and associated memory, portions or combinations of

[0047] Automatic - refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuit, programmable hardware element, ASIC, etc.) without user input directly specifying or performing the action or operation. Thus the term "automatic" is in contrast to "manual," where the action or operation is performed by the user directly. An automatic process can be started by input provided by the user, but once started, it runs without further user input. Automatic processes are often preferred in terms of efficiency and accuracy, as they can be performed significantly faster and / or with higher accuracy than manual processes. An automatic process can be terminated before its normal completion by user input, e.g., via a stop button.

[0048] Configured to - various components can be described as being "configured to" perform one or more tasks. In such contexts, "configured to" is a broad recitation of structure generally meaning "having structure that" performs the task or tasks during operation. As such, the component can not originally be so configured when it is manufactured and / or shipped, but when an action is invoked (e.g., installation of software on the component), the component is configured to perform the action during its operation. In some contexts, "configured to" can mean "having circuitry that" performs the task or tasks during operation. As such, the component can not originally be configured to perform the task(s) prior to being manufactured and / or shipped, but the component can be configured or reconfigured by a user (e.g., an end user, manufacturer, maintenance person, service person, etc.) to perform the task(s) during operation. A component adapted to perform one or more tasks is a broader recitation of "configured to" in that the component can not be so adapted when it is manufactured and / or shipped, but can be so adapted (e.g., reconfigured) by a user or manufacturer.

[0049] For ease of description, various components can be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to." A component configured to perform one or more tasks is expressly intended to be a recitation of structure that is not subject to the interpretation of 35 U.S.C. § 112, paragraph 6.

[0050] Figures 1-2 Wireless communication system

[0051] Figure 1 Examples of a wireless cellular communication system are illustrated. It should be noted that, Figure 1One of many possibilities is represented, and features of the disclosure can be implemented by any of a variety of systems as needed. For example, the embodiments described herein can be implemented in any type of wireless device.

[0052] As shown, an example wireless communication system includes a cellular base station 102 in communication with one or more wireless devices 106A, 106B, etc., and an accessory device 107 over a transmission medium. The wireless devices 106A, 106B, and 107 can be user devices that can be referred to herein as “user equipment” (UE) or UE devices.

[0053] The base station 102 can be a base transceiver station (BTS) or cell site and can include hardware and / or software for implementing wireless communication with the UE devices 106A, 106B, and 107. If the base station 102 is implemented in the context of LTE, it can be referred to as an “eNodeB” or “eNB.” If the base station 102 is implemented in the context of 5G NR, it can alternatively be referred to as a “gNodeB” or “gNB.” The base station 102 can also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a public switched telephone network (PSTN), and / or the Internet, among various possible networks). Thus, the base station 102 can facilitate communication between the UE devices 106 and 107 and / or between the UE devices 106 / 107 and the network 100. Also as used herein, a base station can sometimes be considered to represent the network with respect to a UE in the context of considering the UE’s uplink (UL) and downlink (DL) communications. Thus, a UE in communication with one or more base stations in the network can also be understood as a UE in communication with the network.

[0054] In other implementations, the base station 102 can be configured to provide communication through one or more other wireless technologies, such as an access point supporting one or more WLAN protocols such as 802.11a, b, g, n, ac, ad, and / or ax, or LTE in unlicensed spectrum (LAA).

[0055] The communication area (or coverage area) for the base station 102 can be referred to as a “cell.” The base station 102 and the UEs 106 / 107 can be configured to communicate

[0056] Therefore, base station 102 and other similar base stations (not shown) operating according to one or more cellular communication technologies can be provided as a cell network that can provide continuous or near-continuous overlapping services to UE devices 106A-N and UE devices 107 and similar devices within a geographical area via one or more cellular communication technologies.

[0057] It should be noted that, at least in some cases, UE devices 106 / 107 may communicate using any of a variety of wireless communication technologies. For example, UE devices 106 / 107 may be configured to communicate using one or more of the following: GSM, UMTS, CDMA2000, LTE, LTE-A, NR, WLAN, Bluetooth, one or more Global Navigation Satellite Systems (GNSS, such as GPS or GLONASS), one and / or more mobile television broadcasting standards (e.g., ATSC-M / H). Other combinations of wireless communication technologies (including more than two wireless communication technologies) are also possible. Similarly, in some cases, UE devices 106 / 107 may be configured to communicate using only a single wireless communication technology.

[0058] UE 106A and UE 106B may include handheld devices such as smartphones or tablets, and / or may include any of a variety of devices with cellular communication capabilities. For example, one or more of UE 106A and UE 106B may be wireless devices designed for static or dynamic deployment, such as home appliances, measuring devices, control devices, etc. UE 106B may be configured to communicate with UE device 107, which may be referred to as accessory device 107. Accessory device 107 may be any of a variety of wireless devices, which may typically be a wearable device with a small form factor and limited battery, output power, and / or communication capabilities relative to UE 106. As a common example, UE 106B may be a smartphone carried by a user, and accessory device 107 may be a smartwatch worn by the same user. UE 106B and accessory device 107 may communicate using any of a variety of short-range communication protocols such as Bluetooth or Wi-Fi. In some cases, UE 106B and accessory device 107 may utilize ProSe technology, for example, in a manner supported by cellular base stations, to perform direct peer-to-peer communication. For instance, such ProSe communication may be performed as part of a relay link to support a radio resource control connection between accessory device 107 and BS 102, as described in the various embodiments herein.

[0059] UE 106B can also be configured to communicate with UE 106A. For example, UE 106A and UE 106B may be able to perform direct device-to-device (D2D) communication. D2D communication may be supported by cellular base station 102 (e.g., easily discoverable by BS102, and with various possible forms of assistance), or may be performed in a manner not supported by BS102. For example, it is possible that UE 106A and UE 106B can deploy and perform D2D communication (e.g., including discovery communication) even when BS102 and other cellular base stations have no coverage.

[0060] Figure 2 An exemplary BS102 is shown communicating with UE device 106, which in turn communicates with accessory device 107. UE device 106 and accessory device 107 can be any of a mobile phone, tablet or any other type of handheld device, smartwatch or other wearable device, media player, computer, laptop, UAV, unmanned flight controller, vehicle, or virtually any type of wireless device. In some embodiments, the accessory device may be a wireless device designed to have low cost and / or low power consumption and may support communication with BS102 thanks to a relay link with UE device 106 (and / or another companion device). For example, in Figure 2 In exemplary scenarios, devices that communicate with cellular base stations using relay links with other wireless devices may also be referred to herein as remote wireless devices, remote devices, or remote UE devices, and wireless devices providing such relay links may also be referred to herein as relay wireless devices, relay devices, or relay UE devices. According to some implementations, such BS102, UE 106, and accessory devices 107 may be configured to perform radio resource control procedures on remote wireless devices according to the various techniques described herein.

[0061] Both UE 106 and accessory device 107 may include a device or integrated circuit, referred to as a cellular modem, for facilitating cellular communication. The cellular modem may include one or more processors (processing elements) configured to execute program instructions stored in memory and / or various hardware components described herein. UE 106 and / or accessory device 107 may each execute any of the method embodiments described herein by executing such stored instructions. Alternatively or additionally, UE 106 and / or accessory device 107 may include programmable hardware elements, such as FPGAs (Field-Programmable Gate Arrays), integrated circuits, and / or various other possible hardware components, configured (e.g., individually or in combination) to perform any of or any portion of any of the method embodiments described herein. The cellular modem described herein can be used in UE devices as defined herein, wireless devices as defined herein, or communication devices as defined herein. The cellular modem described herein can also be used in base stations or other similar network-side devices.

[0062] UE 106 and / or accessory device 107 may include one or more antennas for communicating according to one or more RAT standards using one or more wireless communication protocols. In some embodiments, one or both of UE 106 or accessory device 107 may be configured to communicate using a single shared radio component. The shared radio may be coupled to a single antenna or to multiple antennas (e.g., for MIMO) for performing wireless communication. Typically, the radio component may include any combination of baseband processor, analog radio frequency (RF) signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.) or digital processing circuitry (e.g., for digital modulation and other digital processing). Similarly, the radio component may use the aforementioned hardware to implement one or more receive chains and transmit chains.

[0063] Alternatively, UE 106 and / or accessory device 107 may include two or more radio components. For example, in some embodiments, UE 106 and / or accessory device 107 may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol for which it is configured to communicate. As another possibility, UE 106 and / or accessory device 107 may include one or more radio components shared among multiple wireless communication protocols, as well as one or more radio components uniquely used by a single wireless communication protocol. For example, UE 106 and / or accessory device 107 may include shared radio components for communication using either LTE or CDMA2000 1xRTT (or LTE or NR, or LTE or GSM), and for communication using Wi-Fi and BLUETOOTH. TM Each component communicates with a separate radio unit. Other configurations are also possible.

[0064] Figure 3 —Block diagram of UE device

[0065] Figure 3 A possible block diagram of a UE device, such as UE device 106 or UE device 107, is shown. As shown, UE device 106 / 107 may include a System-on-Chip (SOC) 300, which may include components for various purposes. For example, as shown, SOC 300 may include a processor 302 and display circuitry 304, the processor executing program instructions for UE device 106 / 107, and the display circuitry performing graphics processing and providing display signals to a display 360. SOC 300 may also include motion sensing circuitry 370, which may detect motion of UE 106, for example, using a gyroscope, accelerometer, and / or any of various other motion sensing components. Processor 302 may also be coupled to memory management unit (MMU) 340, which may be configured to receive addresses from processor 302 and translate those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, flash memory 310) and / or other circuitry or devices, such as display circuitry 304, radio components 330, I / F 320, and / or display 360. MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, MMU 340 may be included as part of processor 302.

[0066] As shown in the figure, the SOC 300 can be coupled to various other circuits of the UE 106 / 107. For example, the UE 106 / 107 may include various types of memory (e.g., including NAND flash memory 310), connector interface 320 (e.g., for coupling to computer systems, docking stations, charging stations, etc.), display 360, and wireless communication circuitry 330 (e.g., for LTE, LTE-A, NR, CDMA2000, Bluetooth, Wi-Fi, NFC, GPS, etc.).

[0067] UE device 106 / 107 may include at least one antenna and, in some embodiments, may include multiple antennas 335a and 335b for performing wireless communication with a base station and / or other devices. For example, UE device 106 / 107 may use antennas 335a and 335b to perform wireless communication. As described above, UE device 106 / 107 may be configured in some embodiments to perform wireless communication using multiple wireless communication standards or radio access technologies (RATs).

[0068] The wireless communication circuitry 330 may include a Wi-Fi logic component 332, a cellular modem 334, and a Bluetooth logic component 336. The Wi-Fi logic component 332 enables the UE device 106 / 107 to perform Wi-Fi communication over an 802.11 network. The Bluetooth logic component 336 enables the UE device 106 / 107 to perform Bluetooth communication. The cellular modem 334 may be a low-power cellular modem capable of performing cellular communication according to one or more cellular communication technologies.

[0069] As described herein, UE 106 / 107 may include hardware and software components for implementing embodiments of this disclosure. For example, by executing program instructions stored on a storage medium (e.g., a non-transitory computer-readable storage medium), the processor 302 of UE device 106 / 107 may be configured to implement part or all of the methods described herein. In other embodiments, processor 302 may be configured as a programmable hardware element, such as an FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Furthermore, processor 302 may be coupled to, for example, Figure 3Other components shown and / or interoperable with said other components are used to perform radio resource control procedures for remote wireless devices according to various embodiments disclosed herein. Processor 302 may also implement various other applications and / or end-user applications running on UE 106. Alternatively or additionally, one or more components of the wireless communication circuitry 330 (e.g., cellular modem 334) of UE device 106 / 107 may be configured, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), a processor configured as an FPGA (Field Programmable Gate Array), and / or a processor using dedicated hardware components that may include ASICs (Application-Specific Integrated Circuits) to implement part or all of the methods described herein.

[0070] Figure 4 —Block diagram of a base station

[0071] Figure 4 An exemplary block diagram of a base station 102 according to some embodiments is shown. It should be noted that... Figure 4 The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include a processor 404 capable of executing program instructions specific to base station 102. Processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuitry or device, which may be configured to receive addresses from processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0072] Base station 102 may include at least one network port 470. (As mentioned above...) Figure 1 and Figure 2 As described herein, network port 470 can be configured to be coupled to a telephone network and provide access to multiple devices, such as UE devices 106 / 107, that have access to the telephone network.

[0073] Network port 470 (or an additional network port) may also be configured, or alternatively configured, to be coupled to a cellular network, such as the core network of a cellular service provider. This core network may provide mobility-related services and / or other services to multiple devices, such as UE devices 106 / 107. For example, the core network may include, for instance, a Mobility Management Entity (MME) for providing mobility management services, a Serving Gateway (SGW) and / or a Packet Data Network Gateway (PGW) for providing external data connections such as to the Internet, and so on. In some cases, network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide the telephone network (e.g., between other UE devices served by the cellular service provider).

[0074] Base station 102 may include at least one antenna 434 and possibly multiple antennas. One or more antennas 434 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE device 106 / 107 via radio component 430. Antenna 434 communicates with radio component 430 via communication link 432. Communication link 432 may be a receive link, a transmit link, or both. Radio component 430 may be configured to communicate via various wireless communication standards, including but not limited to LTE, LTE-A, NR, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0075] Base station 102 can be configured to perform wireless communication using multiple wireless communication standards. In some cases, base station 102 may include multiple radios that enable base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, base station 102 may include an LTE radio for performing communication according to LTE and a Wi-Fi radio for performing communication according to Wi-Fi. In such a case, base station 102 may be able to operate as both an LTE base station and a Wi-Fi access point. As another possibility, base station 102 may include a multi-mode radio component capable of performing communication according to any of multiple wireless communication technologies (e.g., LTE and NR, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0076] As further described herein, BS102 may include hardware and software components for implementing or supporting specific implementations of the features described herein. According to some embodiments, the processor 404 of base station 102 may be configured to implement some or all of the methods described herein, for example by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, processor 404 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array), or as an ASIC (Application-Specific Integrated Circuit), or a combination thereof. Alternatively (or in addition), in conjunction with one or more of other components 430, 432, 434, 440, 450, 460, 470, the processor 404 of BS102 may be configured to implement or support radio resource control procedures for remote wireless devices according to the various embodiments described herein, and / or any of the various other features of the features described herein.

[0077] Figure 5 —Communication Flowchart

[0078] In some wireless communication systems, reducing and / or avoiding latency and delay may be a priority. In wireless communication systems incorporating beamforming, one type of latency may be associated with changes or updates to the spatial relationship between the BS and the UE and related transmission control. For example, if the BS updates the spatial relationship (e.g., selecting a new transmit (Tx) beam for DL ​​transmissions to the UE), the UE may perform measurements on a reference signal associated with the new Tx beam. These measurements may include beam tracking measurements used by the UE to select the receive (Rx) beam for receiving DL transmissions. Similarly, the UE may use beam tracking measurements to select a Tx beam for transmitting UL transmissions. Furthermore, these measurements may include time, phase, and / or frequency offset measurements, which the UE may use to maintain synchronization with the network and / or other devices such as accessory devices. If periodic reference signals are used to perform these measurements, the delay between the indication of the new spatial relationship and the UE completing the measurements (e.g., and thus being ready to use the new spatial relationship to transmit user data) can be considerable.

[0079] Figure 5 This is a communication flowchart illustrating a method for performing spatial relationship updates in a wireless communication system according to some implementation schemes. Figure 5 This method can reduce the waiting time / delay associated with updates. In various implementations, some elements of the method shown may be executed simultaneously in a different order than shown, may be replaced by other method elements, or may be omitted. Additional method elements may also be executed as needed.

[0080] Figure 5 The various aspects of the method can be implemented by wireless devices and / or cellular base stations (such as UE 106 or 107 and / or BS 102 shown in the figures and described relative to the figures), or more generally, as needed, in combination with any of the computer systems, circuits, elements, components, or devices shown in the figures, among other devices. For example, one or more processors (or processing elements) (in various possibilities, e.g., processors 302, 404, baseband processors, processors associated with communication circuits such as 330, 430, or 432, processors associated with various core network elements, etc.) can cause the UE, network elements, and / or BS to perform some or all of the illustrated method elements. It should be noted that while described in a manner involving the use of communication technologies and / or features associated with LTE, NR, and / or 3GPP specification documents, Figure 5 This description describes at least some elements of the method, but it is not intended to limit this disclosure and can be used in any suitable wireless communication system as needed. Figure 5 The method can be described in several aspects. As shown in the figure, the method can be operated as follows.

[0081] According to some implementation schemes, the UE and BS can establish communication (502). This communication can be performed based on a first spatial relationship. For example, the first spatial relationship may include DL transmission using a first Tx beam of the BS and a first Rx beam of the UE. Similarly, UL transmission may be performed using a first Rx beam of the BS and a first Tx beam of the UE. The beam used for DL ​​transmission may or may not correspond to the beam used for UL transmission.

[0082] In some implementations, the BS can configure multiple spatial relationships for the UE. For example, spatial relationships can be specified by Transmission Configuration Indication (TCI) states. A TCI state can indicate a quasi-co-location (QCL) relationship between one or more of various (e.g., periodic) reference signals (RS) and control and / or data channels (e.g., Physical DL Control Channel (PDCCH) and / or Physical DL Shared Channel (PDSCH) etc.) that the BS can use to transmit to the UE. Therefore, the UE can use (e.g., according to the TCI and the control and / or data channel QCL) RS to decode DL transmissions from the BS. The BS can use higher-layer signaling (e.g., Radio Resource Control (RRC)) to configure any number of TCI states and (e.g., later) use lower-layer signaling (e.g., Downlink Control Information (DCI)) to select the TCI states to use.

[0083] In some implementations, the UE may also establish communication with one or more other BSs (not shown in the figures). This communication between the UE and multiple BSs may be referred to as multiple transmit / receive point (TRP) operation; for example, each BS may be referred to as a TRP. According to some implementations, the UE may have a different spatial relationship with each BS. For example, the UE may use different Rx beams to receive data from each of the different BSs. In some implementations, the UE may be able to receive from multiple BSs simultaneously (e.g., using multiple Rx beams). However, according to some implementations, the UE may be able to transmit to only a single BS at a time. In other words, according to some implementations, the UE may use only one Tx beam at a time (e.g., the Tx beam may be pointed towards the BS). Therefore, according to some implementations, a single BS may be used for UL communication (e.g., once).

[0084] The UE may provide various capability information to the network (e.g., the BS). For example, the UE may indicate the number of Rx beams that the UE is able to (e.g., or is currently configured to) use. Similarly, the UE may indicate its processing delay, such as the time elapsed between the UE receiving control signaling (e.g., DL control information (DCI) etc.) and the implementation of the control signaling. For example, the processing delay may indicate the number of symbols between the indication of receiving TCI state and the UE being ready to receive RS according to the TCI state.

[0085] The UE and BS can communicate using one or more Radio Access Technologies (RATs) such as NR. The UE and BS can exchange application and / or control data in the UL and / or DL ​​directions. Communication and measurements can occur on any frequency or combination of frequencies, including licensed and / or unlicensed spectrum. Communication and measurements can be continuous (e.g., periodically, randomly, as needed, etc.) for any amount of time. For example, communication and measurements can occur on any number of subframes and / or symbols. These measurements can include any radio link measurements, such as signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indication (RSSI), block error rate (BLER), bit error rate (BER), channel impulse response (CIR), channel error response (CER), etc. The UE and / or BS can maintain a historical record of measurements. The UE / BS can compare measurements or metrics calculated based on measurements with one or more thresholds. In such comparisons, the UE / BS can use various parameters, for example, for hysteresis. Measurement results, thresholds, and / or parameters can be configured by the BS (e.g., via the network) and / or by the UE. The UE and / or BS can report measurements (e.g., directly and / or as Channel Quality Indicator (CQI), Channel State Information (CSI), etc.), comparison results, etc., to each other and / or to the network at any time. Based on the measurements, the UE and / or BS can determine which beam changes might be beneficial. Among various possibilities, the UE can track RSs associated with the current spatial relationship and perform measurements using those RSs.

[0086] According to some implementations, the BS can determine updated spatial relationships and can send an indication of the new spatial relationships to the UE (504). The updated spatial relationships can be based on various measurements, thresholds, and / or parameters described above. According to some implementations, the indication can be TCI or include TCI.

[0087] In some implementations, the BS may also determine and update the spatial relationship of the UE relative to one or more other BSs. For example, the BS may receive instructions to update the spatial relationship of one or more other BSs from another BS (e.g., via an X2 interface that the BS can use for coordination) or from network elements. Alternatively, the BS may determine and update the relationship of one or more other BSs based on its own measurements (e.g., indications that the UE is moving, etc.). In other words, the BS may determine changes in the UE's location and use geometry based on these changes to determine updated spatial relationships of itself and / or one or more other BSs.

[0088] In some implementations, the new spatial relationship may be previously configured (e.g., configured by RRC during 502). Therefore, the new spatial relationship may be indicated as a reference (e.g., an index, etc.) to a previously configured spatial relationship, such as one received in signaling from the BS. However, the UE may not have previously tracked the RS associated with the new spatial relationship.

[0089] The UE may receive an indication of a new spatial relationship. The UE may decide not to acknowledge the indication immediately. For example, the UE may decide to delay acknowledging the indication until the UE has completed one or more measurements based on the new spatial relationship (e.g., for beam selection, tracking, and / or refinement using aperiodic or periodic RS).

[0090] According to some implementations, the BS and / or other network elements may schedule aperiodic RS for a new spatial relationship, and the BS may transmit an indication of the scheduled aperiodic RS to the UE (506). The aperiodic RS may be scheduled with consideration for, for example, the UE's processing delay, such that the first symbol of the RS may occur a threshold amount of time after the indication of the changed spatial relationship (e.g., 504).

[0091] Although shown as occurring after an indication of a changing spatial relationship (e.g., 504), it should be understood that this timing relationship is merely an example. An indication of a scheduled non-periodic RS (e.g., 506) may occur before, simultaneously with, or after an indication of a changing spatial relationship (e.g., 504). Similarly, two indications (e.g., 504, 506) may be transmitted in the same or different messages. Two indications may be transmitted in any combination of various message types. For example, DCI and / or MACCE signaling may be used to transmit one or both of these indications.

[0092] In some implementations, aperiodic RSs associated with multiple new spatial relationships can be indicated (e.g., in one message / indication or in multiple messages / indications). For example, in the case of multi-BS operation, aperiodic RSs can be scheduled for different BSs. Aperiodic RSs from various BSs can be scheduled on the same time / frequency resources and / or different time / frequency resources (e.g., or overlapping resources).

[0093] In some implementations, the aperiodic RS can be a channel state information (CSI) RS.

[0094] Sufficient repetitions of schedulable aperiodic RSs are allowed to enable the UE to perform beam tracking using new spatial relationships. In other words, the first set of aperiodic RSs may include one or more repetitions for each Rx beam of the UE (e.g., transmitted using the same Tx beam of the BS to be utilized), as indicated by the UE in 502. For example, if the UE indicates that it has 8 Rx beams (or intends to select from them), the first set of aperiodic RSs may include 8 or more repetitions.

[0095] In some implementations, additional aperiodic RSs may also be scheduled. For example, in addition to the first set of aperiodic RSs (e.g., for beam tracking, as described above), a second set of aperiodic RSs may be scheduled for the UE to perform time, frequency, and / or phase tracking. In some implementations, the second / additional aperiodic RS set may be CSI-RSs configured with tracking RS (TRS) information. For example, the TRS may be a special type of CSI-RS described in section 5.1.6.1.1 of 3GPP 38.214 (e.g., sometimes referred to as a CSI-RS for tracking). According to some implementations, the TRS may be configured via higher-layer signaling such as RRC. Therefore, the second / additional aperiodic RS set may be a TRS.

[0096] According to some implementation schemes, the BS may transmit an indicated (e.g., aperiodic) RS, and the UE may receive the RS (508). For example, in the case of multiple BS operation, each BS may transmit an aperiodic RS on its scheduled time / frequency resources, and the UE may receive the RS from each BS.

[0097] According to some implementation schemes, the UE can select a beam based on RS (510). For example, the UE can use its Rx beam to perform measurements, such as using different Rx beams to receive repetitions of aperiodic RS (e.g., a first set of aperiodic RS). Based on the measurement, the UE can select an Rx beam for a new spatial relationship (e.g., with optimal RSRP or other characteristics). In the case of multiple BS operation, the UE can select the same or different Rx beams for different spatial relationships / BSs.

[0098] In some implementations, the UE may also select a Tx beam for a new spatial relationship (e.g., or, in the case of multiple BS operation, select multiple Tx beams). The selected Tx beam may or may not correspond to the selected Rx beam.

[0099] It should be understood that beam selection can be performed based on aperiodic RS. Therefore, the UE can perform measurements and / or beam selection without waiting for periodic RS.

[0100] According to some implementations, after receiving an aperiodic RS (e.g., and possibly after selecting an Rx beam), the UE may transmit an acknowledgment (512) of the indication of the changed spatial relationship. In other words, the delay in acknowledging the indication of the changed spatial relationship may end after receiving the RS. In some implementations, the acknowledgment may be transmitted using a Tx beam based on the new spatial relationship.

[0101] In some implementations, confirmation may include an indication of the UE's selected Rx and / or Tx beams, or be transmitted along with that indication. In some implementations, this indication may be transmitted separately.

[0102] According to some implementation schemes, the UE and BS can use a new spatial relationship to exchange data (514). For example, DL transmission can be performed by the BS using a Tx beam according to the new spatial relationship, and the UE can use a selected Rx beam to receive DL transmission.

[0103] For UL transmissions, in multi-BS operation, the UE can select the spatial relationship to use. For example, the UE can select to transmit the UL transmission to a specific BS based on measurements of aperiodic RS. In some implementations, which BS the UE should use for the UL transmission can be configured by the network. In some implementations, this indication can be made flexibly (e.g., using DCI). In other implementations, higher-layer signaling such as MAC CE or RRC can be used to make the indication.

[0104] The BS can, for example, use new spatial relationships to provide periodic RS. At least one subset of periodic RS can share the QCL with aperiodic RS, for example, and with the channel used for data exchange. The UE can use the periodic RS that shares the QCL with the channel used for data exchange for path loss measurement and UL power control.

[0105] Figures 6 to 9 and additional information

[0106] supply Figures 6 to 9 And the additional information below, which illustrates the relevant Figure 5 Further considerations and possible specific implementation details of the method are provided and are not intended to limit this disclosure in general. Various variations and alternatives to the details provided below are possible and should be considered to fall within the scope of this disclosure. It should be understood that... Figures 6 to 8 The timeline is not drawn to scale.

[0107] Figure 6The diagram illustrates the delay associated with spatial relationship updates (e.g., via TCI updates) according to some implementations. The timing of the TCI indication 602 may vary depending on whether the new DL-RS in the TCI (e.g., a periodic RS sharing the QCL with the new TCI) was tracked by the UE before the TCI update. If the UE tracks the TCI, for example, if previously configured to measure the new DL-RS and report the CSI based on the new DL-RS, the timing may (e.g., only) be based on the processing delay 604 of the control signaling decoding the TCI indication. This delay may be relatively short, for example, it may end with the acknowledgment (ACK) 606 of the TCI indication.

[0108] However, if the UE has not yet tracked the TCI, the action time can be based on the processing delay 604 of the control signaling indicating the TCI and the tracking wait time 608. For a UE with multiple Rx beams, the UE uses a new spatial relationship to perform multiple DL RS 610a-610n measurements, for example, to find the optimal Rx beam based on multiple measurements. In other words, using a series (e.g., periodic) RSs transmitted by the BS using the new spatial relationship, the UE can sequentially measure instances of the RSs using different Rx beams. Therefore, the total action time (e.g., total delay) 612 can be equal to 604 plus 608. This series of periodic RSs can be transmitted periodically by the base station, but there can be a significant amount of time between each transmission of the periodic RS. Therefore, the tracking wait time 608 can be based in part on the amount of time between the transmissions of the periodic RSs.

[0109] However, according to Figure 5 One approach is to use an aperiodic CSI-RS (or other RS) to update the QCL to reduce beam indication latency. This can be achieved by triggering the aperiodic CSI-RS using TCI indication signaling (or associated signaling). The QCL indication of the aperiodic CSI-RS can be indicated in the new TCI state. Furthermore, the path loss reference signal used for uplink power control can be explicitly indicated in the signaling or implicitly signaled. Additionally, the QCL indication can be extended for multi-TRP operations.

[0110] Figure 7The diagram illustrates the latency associated with spatial relationship updates (e.g., via TCI updates) according to some implementation schemes, for example, by combining aperiodic RS to reduce latency. As shown, the network can trigger aperiodic CSI-RS and TCI indication signaling simultaneously (e.g., or at similar times) to reduce QCL indication waiting time. One or more resources in the aperiodic CSI-RS resource set (710a-710n) can be indicated in the new TCI. For example, the indication can specify the time and frequency of the first repetition of the aperiodic CSI. The aperiodic CSI-RS resource set can be configured to repetition=on, meaning that the base station can transmit CSI-RS resources from the same port (e.g., using the same beam). It should be understood that in Figure 7 In this context, aperiodic RS can be emitted rapidly and continuously (e.g., a repetition may immediately follow or be immediately after a previous repetition). This can be combined with periodic RS (e.g., such as...). Figure 6 In contrast to the periodic RS (shown in the diagram), for a periodic RS, there can be time between consecutive instances of the periodic RS. Therefore, using an aperiodic RS allows the UE to perform measurements with each beam in less time than performing similar measurements with a periodic RS (e.g., 708 may be shorter than 608). Since beam tracking can be performed before confirming the TCI indication, the total action time 712 may be equal to the TCI indication delay 706. However, it should be understood that, according to some embodiments, 706 may be longer than 606.

[0111] Figure 8 The diagram illustrates a combination of a second set of aperiodic RS (814a-814n) according to some implementation schemes for, for example, time, phase, and / or frequency tracking. As shown, the BS can utilize a new QCL assumption to trigger one or more additional CSI-RS resource sets for time / frequency offset tracking and / or phase offset tracking. The additional CSI-RS resource sets can be transmitted after the first CSI-RS resource set used for beam tracking. Therefore, the UE can select an Rx beam (e.g., based on measurements performed using the first CSI-RS resource set 710a-710n) and then perform time, frequency, and / or phase tracking using the additional CSI resource sets 814a-814n. The second CSI-RS resource set can be configured for tracking, for example, as a TRS.

[0112] In some implementations, the additional CSI resource sets 814a-814n can be multiplexed in one or two time slots, with a three-symbol gap between resources. For example, among various possibilities, the TRS can be multiplexed in symbols {4,8} within one time slot, or in symbols {4,8} within two consecutive time slots. It should be understood that other multiplexing arrangements can be used as needed (e.g., with different gaps in different symbols and / or between symbols, including no gap).

[0113] Therefore, the total action time 812 can be equal to the sum of the beam tracking delay 708 and the delay of time, frequency, and / or phase tracking 816. Since beam tracking and time, frequency, and / or phase tracking can be performed before the TCI indication is confirmed, the total action time 812 can be equal to the TCI indication delay 806. However, it should be understood that, according to some embodiments, 806 can be longer than 606 or 706.

[0114] Figure 9 The TCI status is shown, and among various possibilities, the TCI status can be used, for example, according to 3GPP TS 38.331. As shown, QCL information can be provided based on one or more QCL types of one or more cells (e.g., BS).

[0115] The following QCL types can be defined in standard documents (e.g., 3GPP version 15) (see, for example, 5.1.5 in 38.214):

[0116] "QCL-Type A": {Doppler drift, Doppler spread, average delay, delay spread}

[0117] "QCL-Type B": {Doppler drift, Doppler extension}

[0118] "QCL-Type C": {Doppler drift, average delay}, and

[0119] “QCL-type D”: {space Rx parameter}.

[0120] The BS can update the QCL of the DL signal via Transmission Configuration Indication (TCI). The UE can be configured with multiple TCI states via RRC signaling. The BS can select one of the TCI states using lower-layer signaling such as MAC CE or DCI. In some implementations, the BS can provide the DL RS as the QCL source for the TCI state. In other words, a periodic RS transmitted by the BS can be used by any UE associated with a TCI state that shares a QCL with the periodic RS. For example, the QCL source in a TCI state (e.g., for the DL channel) could be a periodic RS in a TCI state that shares a QCL with the DL channel.

[0121] In some implementations, the TCI state can also be used for UL signals and channels to allow the UE to derive the Tx beam for the UL signal. In other words, the UE can use the DL RS indicated in the TCI state as a reference for deriving the Tx beam. In one example, the UE can use the same beam as the beam receiving the DL signal to transmit the UL signal. This reference signal can also be used for path loss measurements to derive the UL transmission power according to the rules defined in Section 7 of TS 38.213.

[0122] Regarding beam tracking for further communication (e.g., in 514), the first CSI-RS resource set (e.g., as discussed relative to 506, 508, and 510 and in...) Figure 7 The first aperiodic RS shown may share a periodic reference signal QCL (e.g., the QCL may be shared). Among various possibilities, the periodic reference signal may be a synchronization signal block (SSB) or a CSI-RS. The periodic reference signal may be in the same component carrier (CC) or in different CCs. The QCL may be based on at least one of the following parameters: Doppler drift, Doppler spread, average delay, delay spread, spatial Rx parameter, and average channel gain. Therefore, the network (e.g., or BS) may determine any one or more of these parameters and may select the RS and / or TCI based on this determination. In one example, the aperiodic RS and the corresponding downlink / uplink channel may share the same TCI indication, where the source RS in the TCI state may be a periodic RS. In another example, the aperiodic RS may be configured to be the source RS in the TCI state of the corresponding downlink / uplink channel, and the aperiodic RS may be indicated using a TCI state with a periodic RS as the QCL source. The second aperiodic CSI-RS resource set may share the same QCL attributes as the first aperiodic CSI-RS resource set (e.g., relative to the first aperiodic CSI-RS resource set). Figure 8 (710 and 814 can share QCL).

[0123] It should be understood that control signaling for TCI indication can be executed in various ways. Based on some implementations, exemplary details of three options for control signaling are explained below.

[0124] In the first option, the TCI indicates that triggering of the non-periodic CSI-RS resource set can be carried by the same DCI. In some implementations, the DCI may include at least the following two fields:

[0125] TCI indication. BS can indicate a TCI state configured in a higher layer such as RRC or MAC CE.

[0126] CSI Requests. A BS can trigger one or two non-periodic CSI-RS resource sets based on resource sets configured by RRC.

[0127] In the second option, the TCI indication may be carried by the MAC CE, and the triggering of an aperiodic CSI-RS resource set may be carried by the DCI used to trigger a PDSCH for the same MAC CE. For example, the DCI may trigger an aperiodic RS and may schedule the MAC CE in the PDSCH. The MAC CE may include a TCI indication. In some embodiments, the DCI may include at least the following field: CSI request. The BS may trigger one or two aperiodic CSI-RS resource sets based on resource sets configured by the RRC. In the MAC CE, the BS may indicate one of the TCI states configured by the RRC.

[0128] In the third option, the TCI indication and triggering of aperiodic CSI-RS resource sets can be carried by a MAC CE or a separate MAC CE. For example, in a MAC CE, the BS can trigger one or two aperiodic CSI-RS resource sets based on resource sets configured by the RRC. Furthermore, in this MAC CE, the BS can indicate one of the TCI states configured by the RRC.

[0129] For any of the signaling options discussed above, the trigger offset between the last symbol of the trigger signaling and the first symbol of the aperiodic CSI-RS resource set may be greater than a threshold reported by the UE. This accommodates the processing delay of the UE decoding the trigger signaling. For example, based on UE capability information, the network / BS can ensure that there is sufficient time for the UE to process the TCI indication and be ready to receive RS using the Rx beam according to the indicated TCI.

[0130] For any of the signaling options discussed above, the number of CSI-RS resources (or other non-periodic RSs) in the first resource set (e.g., 710a-710n) should not be less than the number reported by the UE. For example, based on UE capability information, the network / BS can ensure that there are sufficient repetitions in the first RS set for the UE to receive one (or more) repetitions using each of the UE's Rx beams. In other words, the number of repetitions can be greater than or equal to the number of the UE's Rx beams.

[0131] One change associated with the shift to a new spatial relationship, such as a new TCI, is that the UE can use a different periodic RS for path loss measurement and UL power control. The BS / network can implicitly or explicitly indicate (e.g., and the UE can determine) the RS to be used for path loss measurement (e.g., following the change in spatial relationship). For example, if no additional path loss RS is explicitly indicated, the path loss measurement of the uplink signal to which the new TCI state applies can be based on a periodic reference signal of the QCL source configured as an aperiodic CSI-RS. Therefore, the UE can determine to perform path loss measurement using a periodic RS that shares the QCL with the aperiodic RS. In one example, if the BS triggers aperiodic CSI-RS resource set 1 in TCI handover signaling, and the resources in aperiodic CSI-RS resource set 1 have the same QCL as SSB 1, then SSB 1 can be used as the path loss reference signal. Alternatively, the BS can explicitly indicate the new path loss reference signal via control signaling for TCI handover. In one example, the BS can indicate the path loss reference signal index via DCI or MAC CE, which is selected from the path loss reference signal pool configured by the RRC. In another example, the BS / network can determine a first periodic RS set (e.g., SSB 1) and an aperiodic CSI-RS QCL. In response to determining the first periodic RS set and the aperiodic CSI-RS QCL, the BS / network can determine not to explicitly indicate the path loss RS. The UE can determine to use the first periodic RS set based on the lack of explicit indication of path loss RS, for example, based on the first periodic RS set and the aperiodic CSI-RS QCL.

[0132] In addition, as discussed above, Figure 5 This method can be applied to situations where the UE communicates with multiple BSs simultaneously. For multi-TRP operations, the BS can indicate more than one TCI state, such as two TCI states. The UE can simultaneously receive TCI states through multiple panels (e.g., antennas). The network can trigger two or more aperiodic CSI-RS resource sets for beam tracking of each UE panel. For example, each BS can transmit one aperiodic RS set for each panel of the UE. For example, if the UE has two panels and each panel has eight Rx beams, each BS can transmit two aperiodic RS sets for beam tracking, and each aperiodic RS set can have eight repetitions. Therefore, a total of 16 repetitions can be transmitted (for each BS), corresponding to a total of 16 Rx beams for the UE. Similarly, the network can trigger two or more additional aperiodic CSI-RS resource sets (e.g., one or more from each BS) for time / frequency offset tracking of each UE panel.

[0133] CSI-RS resource sets with identical functionality can be transmitted in overlapping or non-overlapping symbols, depending on the UE's capabilities. In other words, aperiodic RSs for beam tracking can be transmitted by different BSs at the same time, different times, or partially overlapping times. However, aperiodic RSs for time, frequency, and / or phase tracking can be transmitted after aperiodic RSs for beam tracking. Aperiodic RSs for time, frequency, and / or phase tracking can be transmitted by multiple BSs at the same time, different times, or partially overlapping times.

[0134] In some implementations, the UE may support uplink transmission using one antenna panel but downlink reception using two panels. Therefore, the UE may receive two TCI states but may use only (or be indicated by) one TCI state for uplink transmission. If TCI switching signaling applies to both the UL and DL channels, the UE may select one of the TCI states for the uplink channel when two TCI states are indicated. For example, the UE may select a first TCI state, such as one associated with a first BS, or a second TCI state, such as one associated with a second BS. In some implementations, the UE may perform this selection based on measurements (e.g., selecting a BS with lower path loss and therefore lower transmit power requirements). In some implementations, the network may select which TCI state should be used and may configure the UE accordingly, for example, via DCI or higher-level signaling, such as MAC CE or RRC.

[0135] Another exemplary implementation may include a method comprising: a wireless device performing any or all of the foregoing examples.

[0136] Another exemplary embodiment may include a wireless device comprising: an antenna; a radio component coupled to the antenna; and a processing element operatively coupled to the radio component, wherein the device is configured to implement any or all of the foregoing examples.

[0137] Another exemplary embodiment may include an apparatus comprising a processing element configured to cause a wireless device to implement any or all of the foregoing examples.

[0138] Another set of exemplary embodiments may include a non-transitory computer-accessible memory medium comprising program instructions that, when executed at the device, cause the device to implement any or all of the portions of any of the foregoing examples.

[0139] Another exemplary set of implementations may include a computer program comprising instructions for performing any or all portions of any of the examples described above.

[0140] Another exemplary set of embodiments may include an apparatus that includes means for performing any or all elements of any of the examples described above.

[0141] By interpreting each message / signal X received by the user equipment (UE) in the DL as a message / signal X transmitted by the base station, and interpreting each message / signal Y transmitted by the UE in the UL as a message / signal Y received by the base station, any method described herein for operating the UE can serve as the basis for a corresponding method for operating the base station.

[0142] In addition to the exemplary embodiments described above, further embodiments of this disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0143] In some embodiments, a non-transitory computer-readable storage medium may be configured to store program instructions and / or data, wherein, if executed by a computer system, the program instructions cause the computer system to perform a method, such as any method embodiment of the method embodiments described herein, or any combination of method embodiments described herein, or any subset or combination of any such subset of any method embodiments described herein.

[0144] In some implementations, a device (e.g., UE 106 or 107) may be configured to include a processor (or a set of processors) and a memory medium, wherein the memory medium stores program instructions, and the processor is configured to read from the memory medium and execute the program instructions, wherein the program instructions can be executed to implement any of the various method implementations described herein (or any combination of the method implementations described herein, or any subset or combination of any such subset of any method implementations described herein). The device may be implemented in any of a variety of forms.

[0145] As is widely recognized, the use of personally identifiable information should comply with privacy policies and practices that are generally accepted to meet or exceed industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to users.

[0146] Although the above embodiments have been described in considerable detail, many variations and modifications will become apparent to those skilled in the art once the disclosure is fully understood. This disclosure is intended to render the following claims as encompassing all such variations and modifications.

Claims

1. A base station, comprising: a radio; and a processor operably connected to the radio and configured to cause the base station to: communicate with a user equipment device (UE) according to a first spatial relation; transmit, to the UE, an indication to use a second spatial relation and an indication of a first aperiodic reference signal; transmit, to the UE, the first aperiodic reference signal according to the second spatial relation; receive, from the UE, a confirmation of the indication to use the second spatial relation after transmitting the first aperiodic reference signal according to the second spatial relation; and transmit, to the UE, data according to the second spatial relation after receiving the confirmation of the indication to use the second spatial relation from the UE.

2. The base station of claim 1, wherein the processor is further configured to cause the base station to: transmit, to the UE, an indication of a second aperiodic reference signal; transmit, to the UE, the second aperiodic reference signal according to the second spatial relation, wherein the second aperiodic reference signal is transmitted before receiving the confirmation of the indication to use the second spatial relation.

3. The base station of claim 2, wherein the second aperiodic reference signal is configured for time and / or frequency offset tracking measurements.

4. The base station of claim 2, wherein the second aperiodic reference signal is a tracking reference signal.

5. The base station of claim 1, wherein the indication of the first aperiodic reference signal is transmitted in a first downlink control information message that also schedules a first medium access control (MAC) control element (CE), wherein the indication to use the second spatial relation is transmitted in the first MAC CE.

6. The base station of claim 1, wherein the indication to use the second spatial relation and the indication of the first aperiodic reference signal are transmitted in a same medium access control (MAC) control element (CE).

7. The base station of claim 1, wherein the indication to use the second spatial relation and the indication of the first aperiodic reference signal are transmitted in a same downlink control information message.

8. An apparatus for wireless communication, comprising: a processor configured to cause a base station of a cellular network to: transmit, to a user equipment device (UE), data using a first transmit beam; determine to transmit, to the UE, using a second transmit beam; transmit, to the UE, an indication of the second transmit beam and an indication of a first plurality of aperiodic reference signals; transmit, to the UE, the first plurality of aperiodic reference signals using the second transmit beam, wherein the first plurality of aperiodic reference signals are transmitted before receiving, from the UE, a confirmation of the indication of the second transmit beam; receive, from the UE, the confirmation of the indication of the second transmit beam; and ​ ​ transmitting data to the UE using the second transmit beam after receiving the confirmation of the indication of the second transmit beam from the UE.

9. The apparatus of claim 8, wherein the processor is further configured to cause the base station to: transmit, to the UE, a periodic reference signal that is quasi co-located with the first plurality of aperiodic reference signals, wherein the quasi co-location is based on an average channel gain.

10. The apparatus of claim 8, wherein the processor is further configured to cause the base station to: transmit, to the UE, a periodic reference signal that is quasi co-located with the first plurality of aperiodic reference signals, wherein the quasi co-location is based on one or more of: Doppler shift, Doppler spread, average delay, delay spread, or spatial Rx parameters.

11. The apparatus of claim 8, wherein the processor is further configured to cause the base station to: receive, from the UE, an indication of a processing delay of the UE; and determine, based on the processing delay of the UE, an offset between a last symbol of the indication of the second transmit beam and a first symbol of the first plurality of aperiodic reference signals.

12. The apparatus of claim 8, wherein the processor is further configured to cause the base station to: receive, from the UE, an indication of a number of receive beams of the UE; and determine, based on the number of receive beams of the UE, a number of the first plurality of aperiodic reference signals.

13. The apparatus of claim 8, wherein the processor is further configured to cause the base station to: transmit, to the UE, an indication of a third transmit beam of a second base station and an indication of a second plurality of aperiodic reference signals associated with the third transmit beam of the second base station.

14. The apparatus of claim 13, wherein the processor is further configured to cause the base station to: transmit, to the UE, an indication of a third plurality of aperiodic reference signals associated with the third transmit beam of the second base station and a fourth plurality of aperiodic reference signals associated with the second transmit beam; and transmit, to the UE, the fourth plurality of aperiodic reference signals with the second transmit beam, wherein the fourth plurality of aperiodic reference signals are transmitted prior to receiving the confirmation of the indication of the second transmit beam from the UE.

15. A method for wireless communication, comprising: at a base station of a cellular network: establishing communication with a user equipment device (UE) according to a first transmission control state; transmitting, to the UE, an indication to use a second transmission control state and an indication of a first aperiodic reference signal; transmitting, to the UE, the first aperiodic reference signal according to the second transmission control state; receiving, from the UE, a confirmation of the indication to use the second transmission control state, wherein the confirmation is transmitted after transmitting the first aperiodic reference signal; and transmitting, to the UE, data according to the second transmission control state after receiving the confirmation of the indication to use the second transmission control state from the UE. ​ 16. The method of claim 15, further comprising: determining a first periodic reference signal that shares a quasi co-location (QCL) with the first aperiodic reference signal, wherein the first periodic reference signal can be used for path loss measurements; and determining that an explicit indication of a reference signal for path loss measurements according to the second transmission control state is not provided.

17. The method of claim 16, wherein the first periodic reference signal comprises a synchronization signal block.

18. The method of claim 15, wherein using the indication of the second transmission control state comprises an indication of a path loss reference signal index, wherein the method further comprises: transmitting a periodic reference signal according to the path loss reference signal index.

19. The method of claim 15, wherein using the indication of the second transmission control state comprises an indication of using a third transmission control state associated with a second base station.

20. The method of claim 19, wherein the method further comprises: transmitting an indication to the UE to use the third transmission control state for uplink communications.

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