Multiple-input, multiple-output (MIMO) enhancements for high-speed travel

Abstract

The present disclosure relates to techniques for performing wireless communications by a fast-moving user equipment device communicating with a network. The UE may adapt the communication technology in response to the UE's motion. For example, the UE may transmit reference signals to additional transmission and reception points and / or may use different configurations. Similarly, the UE may receive reference signals from additional transmission and reception points.

Description

Technical Field

[0001] The present application relates to wireless communications, including adapting communication procedures of base stations and network elements in wireless communication systems for fast-moving user equipment devices. Background Art

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

[0003] Mobile electronic devices may take the form of smartphones or tablet computers that are commonly carried by users. Wearable devices (also known as accessory devices) are a newer form of mobile electronic device, an example of which is the smartwatch. In addition, low-cost, low-complexity wireless devices intended for static or dynamic deployment are also rapidly increasing as part of the development of the "Internet of Things". In other words, the complexity, capabilities, traffic patterns and other characteristics of the devices required are increasingly wide-ranging. In general, it is desirable to recognize and provide improved support for a wide range of desired wireless communication characteristics. One characteristic may be, for example, the rapid movement of electronic devices on high-speed trains or other forms of rapid transportation. Therefore, improvements in this area are desired. Summary of the Invention

[0004] Embodiments of systems, apparatus, and methods are presented herein for, inter alia, performing a radio resource control connection procedure for fast-moving wireless devices in a wireless communication system.

[0005] As described above, there are an increasing number of use cases for wireless network communications with different types of user equipment devices (UEs) having widely varying capabilities and usage expectations. One direction of expansion of possible use cases supported by wireless communication technologies may include increased use of wireless networks by fast-moving UEs. Wireless communications may be affected by rapid motion, including being affected by different channel characteristics observed by different transmission and reception points (TRPs) (e.g., along the route of a fast-moving UE). For example, a UE moving along the route of a high-speed train may experience / exhibit different characteristics relative to TRPs before and after the UE.

[0006] Thus, the techniques described herein include techniques for a UE (e.g., communicating with a network) to adapt communication technology to such rapid motion. For example, a UE may receive reference signals from multiple TRPs and use the reference signals to demodulate data and / or control signals from the TRPs. In another example, the UE may update the reference signal configuration in response to flexible signaling. In another example, spatial relationships and / or quasi-co-location concepts and procedures may be adapted to support rapidly moving UEs. Different transmission configurations may be used by different TRPs, and the transmission configurations may be flexibly signaled.

[0007] Furthermore, the definition of spatial relationship can be extended to include frequency offset.The UE may transmit reference signals based on spatial relationship and / or based on absolute channel number / frequency.

[0008] In addition, a new operating mode of the UE may be created to support this fast motion. For example, the new mode may be a type of single downlink control information (DCI) multiple TRP mode. The new mode may include the use of multiple transmission configurations.

[0009] The techniques described herein may be implemented in and / or used with a number of different types of devices, including but not limited to mobile phones or smartphones (e.g., iPhones TM , based on Android TM phones), tablets (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., smart watches, smart glasses), laptops, PDAs, portable internet devices, music players, data storage devices, other handheld devices, vehicles, cars, unmanned aerial vehicles (e.g., drones) and unmanned flight controllers, other cellular network infrastructure equipment, servers, and any of a variety of other computing devices.

[0010] This summary is intended to provide a brief overview of some of the subject matter described in this document. Therefore, it should be understood that the above-described features are merely examples and should not be construed as narrowing the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, accompanying drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of the present subject matter may be obtained when the following detailed description of the embodiments is considered in conjunction with the accompanying drawings.

[0012] Figure 1 An exemplary wireless communication system including an accessory device according to some embodiments is shown;

[0013] Figure 2 An exemplary wireless communication system is shown in which two wireless devices can perform direct device-to-device communication according to some embodiments;

[0014] Figure 3 is a block diagram illustrating an example wireless device according to some embodiments;

[0015] Figure 4 is a block diagram illustrating an exemplary base station according to some embodiments;

[0016] Figure 5 is a communication flow diagram illustrating an exemplary method for performing communications in the presence of a fast-moving UE according to some embodiments; and

[0017] Figures 6 to 16 Aspects of performing communications in the presence of fast-moving UEs are shown according to some embodiments.

[0018] While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. However, it should be understood that the drawings and detailed description thereof are not intended to limit this disclosure to the specific forms 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 as defined by the appended claims. DETAILED DESCRIPTION

[0019] Acronyms and abbreviations

[0020] The following acronyms and abbreviations are used in this disclosure:

[0021] 3GPP: Third Generation Partnership Project

[0022] 3GPP2: Third Generation Partnership Project 2

[0023] GSM: Global System for Mobile Communications

[0024] UMTS: Universal Mobile Telecommunications System

[0025] LTE: Long Term Evolution

[0026] IoT: Internet of Things

[0027] QCL: Quasi Co-sited

[0028] TCI: Transmission Configuration Indicator

[0029] RRC: Radio Resource Control

[0030] MAC: Media Access Control

[0031] CE: Control Element

[0032] Tx: Transmit (or transmit)

[0033] Rx: Receive (or receive)

[0034] RS: Reference signal

[0035] CSI: Channel State Information

[0036] the term

[0037] The following are definitions of terms used in this disclosure:

[0038] Memory medium—any of various types of non-transitory memory devices or storage devices. The term "memory medium" is intended to include installation media, such as CD-ROMs, floppy disks, or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, such as hard drives or optical storage devices; registers or other similar types of memory elements, etc. Memory media may also include other types of non-transitory memory or combinations thereof. In addition, the memory medium may be located in the first computer system executing the program, or may be located in a different second computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory media that may reside in different locations in different computer systems connected, for example, via a network. The memory medium may store program instructions (e.g., represented as a computer program) that can be executed by one or more processors.

[0039] Carrier Media—storage media as described above, and physical transmission media such as a bus, network, and / or other physical transmission media that carry signals such as electrical, electromagnetic, or digital signals.

[0040] Programmable hardware elements—include various hardware devices that include multiple programmable function blocks connected via programmable interconnects. Examples include FPGAs (field programmable gate arrays), PLDs (programmable logic devices), FPOAs (field programmable object arrays), and CPLDs (complex PLDs). Programmable function blocks can range from fine-grained (combinational logic units or lookup tables) to coarse-grained (arithmetic logic units or processor cores). Programmable hardware elements may also be referred to as "configurable logic units."

[0041] Computer system—any of various types of computing or processing systems, including a personal computer system (PC), mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing system, or other device or combination 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.

[0042] User Equipment (UE) (or "UE device") - any of various types of computer systems or devices that are mobile or portable and that perform wireless communication. Examples of UE devices include mobile phones or smartphones (e.g., iPhones, TM , based on Android TM phones), tablets (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., smart watches, smart glasses), laptops, PDAs, portable internet devices, music players, data storage devices, other handheld devices, vehicles, cars, unmanned aerial vehicles (e.g., drones) and unmanned flight controllers, etc. In general, the term "UE" or "UE device" can be broadly defined to cover any electronic device, computing device and / or telecommunication device (or combination of these devices) that is easily transportable by a user and capable of wireless communication.

[0043] Wireless Device—Any of various types of computer systems or devices that perform wireless communications. A wireless device may be portable (or mobile), or may be stationary or fixed in place. A UE is an example of a wireless device.

[0044] Communication Device—Any of various types of computer systems or devices that perform communication, where the communication may be wired or wireless. A communication device may be portable (or mobile), or may be stationary or fixed in place. A wireless device is one example of a communication device. A UE is another example of a communication device.

[0045] Base Station—The term “base station” has the full breadth of its ordinary meaning and includes at least a wireless communication station that is installed at a fixed location and used to communicate as part of a wireless communication system.

[0046] Link budget limited—includes the full scope of its ordinary meaning and includes at least a characteristic of a wireless device (e.g., UE) that exhibits limited communication capabilities or limited power relative to devices that are not link budget limited or relative to devices for which a radio access technology (RAT) standard has been developed. A link budget limited wireless device may experience relatively limited receive capability and / or transmit capability, which may be due to one or more factors, such as device design, device size, battery size, antenna size or design, transmit power, receive power, current transmission medium conditions, and / or other factors. Such devices may be referred to herein as “link budget limited” (or “link budget constrained”) devices. A device may be inherently link budget limited due to the size of the device, battery power, and / or transmit / receive power. For example, a smartwatch communicating with a base station via LTE or LTE-A may be inherently link budget limited due to its reduced transmit / receive power and / or antenna reduction. Wearable devices such as smartwatches are generally link budget limited devices. Alternatively, a device may not be inherently link budget limited, e.g., may have sufficient size, battery power, and / or transmit / receive power for normal communication over LTE or LTE-A, but may be temporarily link budget limited due to current communication conditions, e.g., a smartphone at a cell edge, etc. It is noted that the term "link budget limited" includes or encompasses power limitations, and thus a link-limited device may be considered a link budget limited device.

[0047] Processing element (or processor) – refers to any element or combination of elements capable of performing functions in a device (e.g., a user equipment device or a cellular network device). A processing element may include, for example, a processor and associated memory, portions or circuits of individual processor cores, entire processor cores, individual processors, processor arrays, circuits such as ASICs (application-specific integrated circuits), programmable hardware elements such as field-programmable gate arrays (FPGAs), and any of the above combinations.

[0048] Automatic—refers to an action or operation being performed by a computer system (e.g., software executed by the computer system) or a device (e.g., a circuit, a programmable hardware element, an ASIC, etc.) without requiring user input to directly specify or execute the action or operation. Thus, the term "automatically" is in contrast to an action being manually performed or specified by a user, where the user provides input to directly perform the action. An automatic process may be initiated by user-provided input, but the subsequent actions performed "automatically" are not specified by the user, i.e., they are not performed "manually," where the user specifies each action to be performed. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting checkboxes, radio selections, etc.) is not manually filling out the form, even though the computer system must update the form in response to the user's actions. The form can be automatically filled out by a computer system, where the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills it out without requiring any user input to specify the answers to the fields. As indicated above, a user can invoke the automatic filling of a form without participating in the actual filling out of the form (e.g., the user does not manually specify the answers to the fields; they are automatically completed). This specification provides various examples of operations that are automatically performed in response to actions that a user has taken.

[0049] Configured to—Various components may be described as being “configured to” perform one or more tasks. In such contexts, “configured to” is a broad statement that generally means “having the structure” to perform one or more tasks during operation. Thus, a component can be configured to perform a task even when the component is not currently performing the task (e.g., a set of electrical conductors can be configured to electrically connect a module to another module even when the two modules are not connected). In some contexts, “configured to” can be a broad statement that generally means “having the circuitry” to perform one or more tasks during operation. Thus, a component can be configured to perform a task even when the component is not currently turned on. Generally, the circuitry that forms the structure corresponding to “configured to” may include hardware circuitry.

[0050] For ease of description, various components may be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to." Representing a component as being configured to perform one or more tasks expressly does not invoke the sixth paragraph of section 112 of title 35 of the United States Code for that component.

[0051] Figure 1-Figure 2 —Wireless communication system

[0052] Figure 1 An example of a wireless cellular communication system is illustrated. It should be noted that Figure 1This represents one possibility among many, and the features of the present disclosure may be implemented by any of a variety of systems as desired. For example, the embodiments described herein may be implemented in any type of wireless device.

[0053] As shown, the exemplary wireless communication system includes a cellular base station 102 that communicates over a transmission medium with one or more wireless devices 106A, 106B, etc., and an accessory device 107. Wireless devices 106A, 106B, and 107 may be user equipment, which may be referred to herein as "user equipment" (UE) or UE devices.

[0054] Base station 102 may be a base transceiver station (BTS) or a cell site and may include hardware and / or software that enables wireless communications with UE devices 106A, 106B, and 107. If base station 102 is implemented in the context of LTE, it may be referred to as an "eNodeB" or "eNB." If base station 102 is implemented in the context of 5G NR, it may alternatively be referred to as a "gNodeB" or "gNB." Base station 102 may also be equipped to communicate with 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, base station 102 may facilitate communications between UE devices 106 and 107 and / or between UE devices 106 / 107 and network 100. Also as used herein, with respect to a UE, a base station may sometimes be considered to represent the network when considering uplink (UL) and downlink (DL) communications of the UE. Therefore, a UE communicating with one or more base stations in a network may also be understood as a UE communicating with the network.

[0055] In other embodiments, the base station 102 may be configured to provide communications via 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 bands (LAA).

[0056] The communication area (or coverage area) of the base station 102 may be referred to as a “cell.” The base station 102 and the UEs 106 / 107 may be configured to communicate over a transmission medium using any of a variety of radio access technologies (RATs) or wireless communication technologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE-Advanced (LTE-A), NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, etc.

[0057] Thus, 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 nearly continuous overlapping service to UE devices 106A-N and UE device 107 and similar devices within a geographic area via one or more cellular communication technologies.

[0058] Note that, at least in some cases, UE devices 106 / 107 may be configured to 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 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 broadcast standards (e.g., ATSC-M / H), etc. Other combinations of wireless communication technologies (including more than two wireless communication technologies) are also possible. Similarly, in some cases, UE devices 106 / UE devices 107 may be configured to communicate using only a single wireless communication technology.

[0059] UE 106A and UE 106B may comprise handheld devices such as smartphones or tablets, and / or may comprise any of various types of devices with cellular communication capabilities. For example, one or more of UE 106A and UE 106B may be wireless devices intended for static or dynamic deployment, such as appliances, measurement devices, control devices, and the like. UE 106B may be configured to communicate with a UE device 107, which may be referred to as an accessory device 107. Accessory device 107 may be any of various types of wireless devices, typically wearable devices with a smaller 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 various short-range communication protocols, such as Bluetooth or Wi-Fi. In some cases, UE 106B and accessory device 107 can utilize proximity services (ProSe) technology, for example, in a manner supported by a cellular base station, to perform direct peer-to-peer communications. For example, such ProSe communications can be performed as part of a relay link to support a radio resource control connection between accessory device 107 and BS 102, such as according to various embodiments described herein.

[0060] UE 106B may 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) communications. D2D communications may be supported by cellular base station 102 (e.g., BS 102 may facilitate discovery, as well as various possible forms of assistance), or may be performed in a manner not supported by BS 102. For example, it may be possible for UE 106A and UE 106B to arrange and perform D2D communications (e.g., including discovery communications) even when BS 102 and other cellular base stations have no coverage.

[0061] BS 102 may control one or more transmission and reception points (TRPs) and may use the TRPs to communicate with UEs. The TRPs may be collocated with the BS and / or at a separate physical location.

[0062] Figure 2 An exemplary BS 102 is shown communicating with a UE device 106, which in turn communicates with an accessory device 107. The UE device 106 and the accessory device 107 may be any of a mobile phone, a tablet or any other type of handheld device, a smartwatch or other wearable device, a media player, a computer, a laptop, an unmanned aerial vehicle (UAV), an unmanned flight controller, a 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 benefit from a relay link with the UE device 106 (and / or another companion device) to support communications with the BS 102. For example, in Figure 2 In the exemplary scenario of FIG, a device that utilizes a relay link with another wireless device to communicate with a cellular base station may also be referred to herein as a remote wireless device, a remote device, or a remote UE device, and a wireless device that provides such a relay link may also be referred to herein as a relay wireless device, a relay device, or a relay UE device. According to some embodiments, such BS 102, UE 106, and accessory device 107 may be configured to perform radio resource control procedures for the remote wireless device according to the various techniques described herein.

[0063] UE 106 and accessory device 107 may each include a device or integrated circuit known as a cellular modem for facilitating cellular communications. The cellular modem may include one or more processors (processing elements) configured to execute program instructions stored in a memory and / or various hardware components described herein. UE 106 and / or accessory device 107 may each perform any of the method implementations described herein by executing such stored instructions. Alternatively or in addition, UE 106 and / or accessory device 107 may include a programmable hardware element, such as an FPGA (field programmable gate array), an integrated circuit, and / or any of various other possible hardware components, configured to (e.g., individually or in combination) perform any of the method implementations described herein or any portion of any of the method implementations described herein. The cellular modem described herein may be used in a UE device as defined herein, a wireless device as defined herein, or a communication device as defined herein. The cellular modem described herein may also be used in a base station or other similar network-side device.

[0064] The UE 106 and / or the accessory device 107 may include one or more antennas for communicating in accordance with one or more RAT standards using one or more wireless communication protocols. In some embodiments, one or both of the UE 106 or the accessory device 107 may be configured to communicate using a single shared radio. The shared radio may be coupled to a single antenna, or may be coupled to multiple antennas (e.g., for MIMO) for performing wireless communications. Generally, the radio may include any combination of a 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 may implement one or more receive chains and transmit chains using the aforementioned hardware.

[0065] Alternatively, UE 106 and / or accessory device 107 may include two or more radios. For example, in some embodiments, UE 106 and / or accessory device 107 may include a separate transmit chain and / or receive chain (e.g., including separate antennas and other radios) for each wireless communication protocol with which it is configured to communicate. As another possibility, UE 106 and / or accessory device 107 may include one or more radios shared between multiple wireless communication protocols, and one or more radios used uniquely by a single wireless communication protocol. For example, UE 106 and / or accessory device 107 may include a shared radio for communicating using either LTE or CDMA2000 1xRTT (or LTE or NR, or LTE or GSM), and a shared radio for communicating using Wi-Fi and BLUETOOTH. TM Each of the two devices communicates with a separate radio component. Other configurations are also possible.

[0066] Figure 3 —Block diagram of UE equipment

[0067] 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 a chip (SOC) 300, which may include components for various purposes. For example, as shown, SOC 300 may include a processor 302, which may execute program instructions for UE device 106 / 107, and display circuitry 304, which may perform graphics processing and provide display signals to display 360. SOC 300 may also include motion sensing circuitry 370, which may detect motion of UE 106, for example, using a gyroscope, an accelerometer, and / or any of various other motion sensing components. Processor 302 may also be coupled to a 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 circuits or devices, such as display circuit 304, radio 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.

[0068] As shown, the SOC 300 may 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), a connector interface 320 (e.g., for coupling to a computer system, a docking station, a charging station, etc.), a display 360, and wireless communication circuitry 330 (e.g., for LTE, LTE-A, NR, CDMA2000, Bluetooth, Wi-Fi, NFC, GPS, etc.).

[0069] The UE device 106 / 107 may include at least one antenna and, in some embodiments, may include multiple antennas 335a and 335b for performing wireless communications with a base station and / or other devices. For example, the UE device 106 / 107 may use antennas 335a and 335b to perform wireless communications. As described above, the UE device 106 / 107 may, in some embodiments, be configured to perform wireless communications using multiple wireless communication standards or radio access technologies (RATs).

[0070] Wireless communication circuitry 330 may include Wi-Fi logic 332, a cellular modem 334, and Bluetooth logic 336. Wi-Fi logic 332 is configured to enable UE device 106 / 107 to perform Wi-Fi communications over an 802.11 network. Bluetooth logic 336 is configured to enable UE device 106 / 107 to perform Bluetooth communications. Cellular modem 334 may be a relatively low-power cellular modem capable of performing cellular communications according to one or more cellular communication technologies.

[0071] As described herein, the UE 106 / 107 may include hardware components and software components for implementing embodiments of the present disclosure. For example, by executing program instructions stored on a storage medium (e.g., a non-transitory computer-readable memory medium), the processor 302 of the UE device 106 / 107 may be configured to implement part or all of the methods described herein. In other embodiments, the 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). In addition, the processor 302 may be coupled to a processor such as a processor 106 / 107. Figure 3The other components shown and / or may interoperate with the other components to perform radio resource control processes for remote wireless devices in accordance with various embodiments disclosed herein. The processor 302 may also implement various other applications and / or end-user applications running on the UE 106. Alternatively or in addition, one or more components of the wireless communication circuitry 330 (e.g., the cellular modem 334) of the UE device 106 / 107 may be configured to implement part 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), a processor configured as an FPGA (field programmable gate array), and / or using dedicated hardware components that may include an ASIC (application-specific integrated circuit).

[0072] Figure 4 —Block diagram of a base station

[0073] Figure 4 1 shows an exemplary block diagram of a base station 102 according to some embodiments. Note that Figure 4 The base station 102 is only one example of a possible base station. As shown, the base station 102 may include a processor 404 that may execute program instructions for the base station 102. The processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuit or device that may be configured to receive addresses from the processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0074] The base station 102 may include at least one network port 470. Figure 1 and Figure 2 As described in , the network port 470 can be configured to couple to a telephone network and provide multiple devices, such as the UE devices 106 / 107 , with access to the telephone network.

[0075] The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and / or other services to a plurality of devices, such as the UE devices 106 / 107. For example, the core network may include, for example, 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 the like. In some cases, the network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., between other UE devices served by the cellular service provider).

[0076] 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 devices 106 / 107 via radio 430. Antenna 434 communicates with radio 430 via communication chain 432. Communication chain 432 may be a receive chain, a transmit chain, or both. Radio 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, and the like.

[0077] Base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some cases, base station 102 may include multiple radios that may 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 communicating according to LTE and a Wi-Fi radio for communicating according to Wi-Fi. In such a case, base station 102 may be capable of operating as both an LTE base station and a Wi-Fi access point. As another possibility, base station 102 may include a multimode radio capable of communicating 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.).

[0078] As further described later herein, BS 102 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 part 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, the processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit), or a combination thereof. Alternatively (or in addition), in combination with one or more of the other components 430, 432, 434, 440, 450, 460, 470, the processor 404 of BS 102 may be configured to implement or support implementation of any of the various other features of the radio resource control process for remote wireless devices according to the various embodiments described herein, and / or the features described herein.

[0079] Figure 5 -Communication Flowchart

[0080] High-speed train (HST) is a deployment scenario that is of great interest to some operators, especially those from countries / regions where HST systems are deployed (e.g., China). Therefore, HST enhancements may be part of Release 17 further enhancements (Fe) Multiple-Input Multiple-Output (MIMO) (FeMIMO). For example, a UE may travel between two transmit and receive points (TRPs) in an HST scenario or other scenarios involving fast travel. The UE may observe very high positive Doppler drift from one TRP and very high negative Doppler drift from the other TRP. As a result, the composite channel may change rapidly. For example, Doppler drifts approaching 4 kHz or even greater may be observed. Such drifts may potentially degrade the channel capability and / or make it very challenging for the UE to perform accurate channel estimation.

[0081] There are two broad approaches to mitigating this channel variation. In one approach, the UE can estimate two separate Doppler shifts, for example, one Doppler shift from one TRP, although more than two TRPs are also contemplated. Different Doppler shifts can be used to assist the UE in channel estimation, for example, by performing different channel estimates for different TRPs. In another approach, the network can compensate for Doppler shift. Thus, the network can determine the Doppler shift for each TRP in order to perform compensation.

[0082] Figure 5 is a communication flow diagram illustrating an exemplary method for performing communications in the presence of a fast-moving UE according to some embodiments. Figure 5 The method can alleviate some of the communication challenges associated with rapid motion. In various embodiments, some of the elements of the method shown can be performed simultaneously in a different order than shown, can be replaced by other method elements, or can be omitted. Additional method elements can also be performed as needed.

[0083] Figure 5 Aspects of the method may be implemented by a UE such as UE 106 or 107, a cellular network, one or more transmission and reception points (TRPs) and / or one or more BSs 102, for example, as shown in the figures and described with reference to the figures, or more generally in conjunction with any of the computer systems, circuits, elements, components or devices shown in the figures, etc. For example, one or more processors (or processing elements) (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., among other possibilities) may cause the UE, network element and / or BS to perform some or all of the elements of the method shown. Note that although the present invention is described in a manner involving the use of communication techniques and / or features associated with LTE, NR and / or 3GPP specification documents, Figure 5At least some elements of the method, but this description is not intended to limit the present disclosure and can be used in any suitable wireless communication system as needed Figure 5 Aspects of the Method As shown in the figure, the method can be operated as follows.

[0084] According to some embodiments, the UE may establish communication (502) with the network via two TRPs (TRP 501a and TRP 501b). It should be understood that, according to various embodiments, the TRPs may be controlled by a single BS or by different BSs. The UE may be moving. For example, the UE may move toward one of the TRPs 501 and away from the other TRP 501. For example, the UE may be traveling on a high-speed train (or in a car, drone, UAV, or other vehicle) along a route (e.g., train tracks, highways, roads, etc.), and TRP 501a and TRP 501b may be along or near the route. Thus, the UE may be getting closer to one TRP 501 and further away from the other TRP 501. Therefore, the signals exchanged between the UE and the TRPs may be affected by the motion. For example, the signals may exhibit Doppler shift or frequency offset due to the motion of the UE.

[0085] In accordance with some embodiments, the network (e.g., controlling either or both of BS 102 and / or TRP 501a and / or TRP 501b) and / or the UE may determine that the UE is moving rapidly (504). For example, the network and / or TRP 501 may determine that the UE is moving rapidly based on any or all of the following: radio measurements (e.g., of reference signals or other communications transmitted by the UE), reports from the UE (e.g., radio measurements made by the UE and / or based on motion sensing features of the UE (such as accelerometers, motion sensors, gyroscopes, global navigation satellite systems such as GPS, etc.), knowledge of the UE's recent motion and / or knowledge of traffic information (e.g., train schedules, highway routes, knowledge of the motion of other UEs (e.g., multiple UEs in the same train / vehicle), etc.). Thus, in some embodiments, the network may be configured to infer UE movement from a variety of different measurements or inputs. The UE may similarly determine its motion, for example, based on similar information.

[0086] In some embodiments, the UE may explicitly indicate information about its movement to the network. For example, the UE may indicate to the network that it is on a high-speed train or is otherwise moving rapidly. Based on receiving such an indication, the network may determine that the UE is moving rapidly.

[0087] According to some embodiments, the network and / or UE may adapt the communication technology based on the motion of the UE (506). Among various possibilities, such adaptation may include techniques for coordinating communications between two TRPs (e.g., a TRP toward which the UE is moving and a TRP away from which the UE is moving). Such adaptation may include enhancements in any of the following areas:

[0088] For example, enhancements for downlink data transmission and reception via a reference signal (RS) for demodulation. For example, a demodulation reference signal (DMRS) associated with a physical downlink shared channel (PDSCH) may be scheduled, transmitted, and / or processed differently. For example, two TRPs may transmit DMRS or other RS to a UE, for example, for use by UEs communicating with these TRPs simultaneously. RSs transmitted by different TRPs may be coordinated and orthogonalized in any of a variety of ways (e.g., time division, frequency division, code division, and / or port division). For example, two TRPs may transmit UE-specific RSs to a UE during a first time slot (or frame or other time period) (e.g., during the same or different symbols of the first time slot).

[0089] Enhancements for transmission of control information to the UE, such as downlink control information (DCI) transmissions. For example, RSs (e.g., DMRSs and / or other RSs) associated with a physical downlink control channel (PDCCH) may be scheduled, transmitted, and / or processed differently, e.g., for reliability enhancement. For example, two TRPs may transmit RSs to the UE, e.g., for use by UEs communicating with these TRPs simultaneously. Multiple transmission configuration indication (TCI) states may be provided to the UE and used for communications between the UE and the network, and / or a new quasi-co-location (QCL) type may be defined and provided to the UE and used for communications between the UE and the network.

[0090] Enhancement of spatial relationship of uplink RSs. For example, the configuration of uplink RSs such as sounding RSs (SRSs) or DL path loss RSs for UL power control may be adapted.

[0091] New operating modes (e.g., HST mode). For example, a high-speed travel mode can be created as a special case (e.g., or a variation thereof) of a single downlink control information (DCI) multiple TRP mode. This new mode can be activated by explicit indication (e.g., in DCI, RRC, MAC CE, or other control signaling) or by implicit indication (e.g., based on other conditions).

[0092] According to some embodiments, the UE and the network (e.g., TRP 501a and / or TRP 501b) may communicate using the adapted communication technology (508). For example, when the UE is rapidly traveling between TRP 501a and TRP 501b, the UE and the network may exchange data and / or control information using the adapted communication technology. The data and / or control information may be exchanged in the UL and / or DL directions.

[0093] The UE and the network may continue to adapt the communication technology and communicate as the UE travels. For example, as the UE passes through a TRP, the relationship to the TRP (e.g., Doppler shift, frequency offset, spatial relationship, QCL, and / or other parameters) may change. For example, as the UE passes through a TRP, the frequency offset relative to the TRP may change sign.

[0094] The following describes additional examples and information regarding various types of adaptations to high-speed motion of the UE (e.g., as described above with respect to 506). It should be understood that according to some embodiments, these examples can be used together (e.g., in any of various combinations) and / or separately.

[0095] Downlink data enhancement

[0096] When a UE travels at very high speeds towards or further away from the TRP, the UE may experience large frequency offsets in terms of Doppler shift, which may be linearly proportional to the UE speed and the carrier frequency. Thus, at high frequencies and when the UE is traveling very fast (e.g., close to or above 350 km / hr, as in a high-speed train (HST)), the frequency offset (Doppler shift) caused by the UE movement may approach or exceed 2 kHz, which is equivalent to multiple channel phase and amplitude change cycles per millisecond, which may be different from typical multi-TRP operation. Due to the high-speed movement in an HST scenario, it may be challenging for the UE to handle the fast changes.

[0097] Figure 6Downlink data enhancement (e.g., via PDSCH DMRS enhancement) according to some embodiments is shown. As shown, a UE 106 may travel (e.g., on a train) between two TRPs (TRP 1 and TRP 2). It should be understood that, according to some embodiments, the TRPs may be controlled by a single BS 102 or by different BSs. The RSs transmitted by different TRPs may be orthogonalized in any of a variety of ways (e.g., time division, frequency division, code division, and / or port division). Thus, the RSs transmitted by a TRP can be used for temporally overlapping (e.g., simultaneously) communications with the two TRPs. In other words, the UE may maintain communication with the two TRPs simultaneously. For example, the two TRPs may transmit RSs to the UE during the same time slot. Different TRPs may use the same or different symbols of the same time slot.

[0098] According to some embodiments, the TRP may transmit DMRS or other RS according to a non-single frequency network (SFN) mode. For example, DMRS from different TRPs may be transmitted to a fast-moving UE that is communicating with both TRPs under the following circumstances: (1) at different times (e.g., time division multiplexing (TDM)), and / or (2) at different frequency locations (e.g., frequency division multiplexing (FDM)), and / or (3) with different DMRS ports, and / or (4) with different orthogonal codes (e.g., code division multiplexing (CDM)). For example, in response to determining that the UE is moving rapidly (e.g., in 504), the network may determine to transmit DMRS (and / or other RS) from multiple TRPs for use by the UE, for example, simultaneously or at overlapping or alternating times. The UE may use the DMRS (and / or other RS) when demodulating downlink data and / or control information transmitted by the corresponding TRP.

[0099] In some embodiments, the RS (e.g., DMRS) transmitted to a UE from different TRPs may be UE-specific. In other words, a specific RS may be transmitted to a UE based on any of a variety of factors, such as the UE's motion, scheduled communications between the UE and the TRP, radio measurements of the channel between the UE and the TRP, etc. According to some embodiments, the RS transmitted to a UE from different TRPs may be the same or may be different.

[0100] In some embodiments, unlike current DMRS designs, different TRPs can transmit different RS (e.g., DMRS) patterns to the UE. Thus, the UE can separate RSs from different TRPs. This differentiation between RSs can reduce channel variations caused by high UE mobility and improve UE channel estimation quality. Thus, according to some embodiments, RSs can be both UE-specific and TRP-specific.

[0101] like Figure 7As shown, DMRSs from different TRPs (e.g., or UE-specific RSs) may be transmitted at different times (e.g., symbols 0 to 13 of a time slot are shown horizontally in time; the frequency domain is shown vertically). For example, the DMRS position (e.g., in time / frequency) of a first TRP (e.g., TRP 501a) may be known from existing standards and / or configuration information. The DMRS position (e.g., in time / frequency) of a second TRP (e.g., TRP 501b) may be indicated via additional control information (e.g., radio resource control (RRC), medium access control (MAC) control element (CE) and / or downlink control information (DCI), etc.). Among various possibilities, the control information may be sent via multiple TRPs or via one of the TRPs. For example, both the first TRP and the second TRP may transmit control information, or only one of the TRPs (e.g., the first TRP or the second TRP) may transmit control information. Similarly, the DMRS position of the second TRP may be implicitly determined by the UE.

[0102] For example, the new (e.g., additional) symbol positions of the DMRS for the second (e.g., additional) TRP may be explicitly defined in the technical specification or defined relative to the symbol positions of the DMRS for the first TRP. For example, the network may send control information from the second UE to the UE indicating the position of the DMRS. The control information may explicitly identify the specific position of the DMRS (e.g., in terms of symbols and resource elements (REs)). For example, in Figure 7 In the example, the position of the DMRS of TRP 2 may be in symbols 1 and 8. Alternatively, the control information may indicate the offset of the DMRS position of the second TRP relative to the first TRP (e.g., in Figure 7 In the example, the position of the DMRS of TRP 2 can be offset by 1 symbol relative to the DMRS of TRP1).

[0103] In some embodiments, when multiple DMRS positions are configured, existing DMRS symbol positions (e.g., symbols designated for DMRS transmission according to existing specifications and / or control information) may be divided between a first TRP and a second TRP. In other words, if a first number of REs in a timeslot may be designated for RS (e.g., by prior control information and / or standards), the first number of REs may be subdivided such that a subset of the REs is used for RSs in TRP 1 and a second subset of the REs is used for RSs in TRP 2. When configuring a second RS, control information may be used to indicate the subdivision of the RS positions.

[0104] It should be understood that although the time positions (e.g., symbols) of the RSs associated with the TRPs are different, the UE is communicating with the TRPs simultaneously. In other words, the time positions overlap and are time division multiplexed (TDMd). For example, the TRPs may transmit RSs in different symbols of the same time slot, e.g., a first TRP may use one or more first symbols, and a second TRP may use one or more second symbols.

[0105] Figure 8 DMRS transmissions from different TRPs on different frequencies according to some embodiments are shown. Any combination of the above techniques may be used to indicate Figure 8 For example, the RS position can be indicated explicitly or using an offset; the existing RS position can be subdivided.

[0106] Another method for orthogonalizing the RSs of different TRPs may be via code division multiplexing (CDM). For example, DMRSs from different TRPs may be transmitted in different CDM groups. According to some embodiments, each CDM group may support up to four ports via orthogonal codes. Different CDM groups may be orthogonalized via frequency division multiplexing (FDM). Depending on the number of CDM groups configured for the UE, various methods may be used to orthogonalize the RSs of the TRPs.

[0107] When a single CDM group is configured, there may be one or more (e.g., predefined) ports indicated for DMRS (e.g., or other RS) in the CDM group. Thus, the one or more ports indicated for the RS can be used for transmission of RS and / or data for one TRP. One or more other ports (e.g., the remaining ports) of the CDM group can be used for transmission of RS and / or data for another TRP. In some embodiments, which ports are used for which TRPs may be explicitly signaled or implicitly indicated in the control information (e.g., based on scheduling a single TRP on a specific port). For example, if 1 CDM group is configured (e.g., via DCI) and the DCI (or other control information) indicates a port (or multiple ports) for DMRS, then that port (or multiple ports) can be used for the first TRP; any other ports can be used for DMRS for other TRPs. In some embodiments, data from each TRP may use the same port as the RS from the corresponding TRP.

[0108] When two CDM groups are configured, the DMRS ports in the first CDM group may correspond to one TRP, and the DMRS ports in the second CDM group may correspond to another TRP. Figure 9As shown, the REs may be divided between the two CDM groups (e.g., alternating in this example, but other divisions may be used as needed). Each CDM group may be used for DMRS from a different TRP. In the example shown, the REs in the first CDM group may be used for DMRS from the first TRP, and the REs in the second CDM group may be used for DMRS from the second TRP. Transmission of CDM group 1 may be performed by one TRP, and transmission of CDM group 2 may be performed by another TRP. The UE may (e.g., jointly) use the DMRS of each TRP (e.g., each CDM group) to demodulate the corresponding data. For example, in the case where two TRPs transmit duplicate data (e.g., TRP2 transmits a copy of the data transmitted by TRP 1), the UE may use a combination of the DMRS from each TRP to estimate the channel and demodulate the data. Alternatively, in the case where two TRPs transmit different data, the UE may use the DMR from one TRP to estimate the channel from the TRP and demodulate the data. The data may be transmitted at a different frequency than the RS (eg, simultaneously with the RS), at a different time than the RS (eg, a different symbol, but possibly the same frequency), and / or using a different antenna port than the RS.

[0109] When three CDM groups are configured, the DMRS ports in a first subset (eg, 1 or 2) of the CDM groups may correspond to one TRP, and the DMRS ports in the remaining groups in the CDM groups may correspond to another TRP. Figure 10 An example with three CDM groups according to some embodiments is shown. CDM group 0 may correspond to a first TRP, and CDM groups 1 and 2 may correspond to a second TRP. In the example shown, the REs in CDM group 0 may be used for the DMRS corresponding to the first TRP, and the REs in CDM groups 1 and 2 may be used for the DMRS corresponding to the second TRP. The UE may (e.g., jointly, in the case where different TRPs transmit duplicate data) use the DMRS from both the first TRP and the second TRP transmitted in CDM groups 0, 1, and 2 to decode data for the PDSCH channel. Alternatively, in the case where the TRPs transmit different data, the UE may use the DMRS of CDM group 1 to decode data for CDM group 2, for example, because CDM groups 1 and 2 are transmitted by the same TRP and therefore share channel characteristics. Note that partitioning may also be performed such that CDM groups 0 and 1 correspond to the first TRP, and CDM group 2 corresponds to the second TRP.

[0110] In another method for orthogonalizing RS, different ports can be used to transmit RS from different TRPs. For example, the UE can use different antenna ports to receive RS from different TRPs.

[0111] In some embodiments, a second antenna port field may be introduced in the DCI. The second antenna port field may be a duplicate (e.g., a copy) of the existing port field. Thus, the network (e.g., a base station) may separately indicate the antenna port configuration for RSs from each TRP, for example, via DCI. For example, in a DCI message to a UE, the network may indicate the first port for the DMRS for TRP 1 and the second port for the DMRS for TRP 2.

[0112] In some implementations, a new table for interpretation of the Antenna Port field may be introduced (e.g., in 38.212). This table may specify at least some values of the Antenna Port field for two different ports (e.g., for different TRPs). Thus, for this Antenna Port field indication, two groups of DMRS ports may be defined: one group of DMRS ports for the first TRP and a second group of DMRS ports for the second TRP.

[0113] In some embodiments, the data transmitted from the TRPs (e.g., associated with the RSs) may be the same. For example, a first TRP may transmit first data to a UE during a time slot. During the same time slot (e.g., in the same and / or different symbols, for example, using any of the orthogonalization techniques discussed above), a second TRP may transmit second data to the UE. The second data may be a copy of the first data. The first data may be demodulated using the RS from the first TRP, and the second data may be demodulated using the RS from the second TRP. The UE may combine these channels before decoding the data. In other words, the UE may rely on both the first data and the second data (e.g., a copy of the first data) to determine the content of the first data / second data.

[0114] Downlink Control Channel Enhancement

[0115] Figures 11 to 15 Various aspects of downlink control channel (e.g., PDCCH) reliability enhancement according to some embodiments are shown. According to some embodiments, multiple TRPs may use the same control resource set (CORESET) to transmit control information to the UE. Similar to the discussion above on downlink data enhancement, the RSs transmitted by different TRPs may be orthogonalized in various ways (e.g., frequency division, code division, and / or port division). Thus, the RSs transmitted by a TRP may be used for temporally overlapping (e.g., simultaneous) communications with two TRPs. In other words, the UE may maintain communication with two TRPs simultaneously. For example, two TRPs may transmit UE-specific RSs to the same UE during each symbol of the CORESET. In addition, as described above, the RSs may be TRP-specific, and the UE may distinguish between RSs of different TRPs.

[0116] Furthermore, according to some embodiments, the various techniques discussed above (e.g., with respect to downlink data) may be adapted for use with control channels. It should be understood that current control channel designs include RSs in each symbol (e.g., time interval), and therefore, time division may not be applicable. However, according to some embodiments, time division, as discussed above with respect to data augmentation, may also be applied to control channels that do not include RSs in each time interval.

[0117] In some embodiments, the PDCCH may have separate RS (e.g., DMRS) transmissions from different TRPs. For example, in addition to the first TRP, the RS associated with the PDCCH may be transmitted, for example, from a second TRP.

[0118] Frequency division can be used as a method for orthogonalizing RSs of different TRPs. Figure 11 FIG2 shows a combined resource grid according to some embodiments, for example showing DMRS transmissions from each TRP on a control channel. Figure 12 shows the DMRS transmission from TRP 1, and Figure 13 DMRS transmission from TRP 2 is shown. In other words, Figure 12 and Figure 13 Separate RS transmissions are shown for TRPs 1 and 2, respectively, according to some embodiments.

[0119] As shown, DMRS may be transmitted by each TRP in each symbol of a CORESET. DMRS may be transmitted by each TRP at various frequencies (e.g., in periodically spaced REs). In the example shown, DMRS may be transmitted by each TRP in every four REs in each CORESET symbol. Note that other intervals may be used as needed. For example, the RE offset of the DMRS for TRP 2 is three, and the RE offset of the DMRS for TRP 1 is one. In other words, the DMRS for each TRP may occur in every four REs, with TRP 1 in the second RE (e.g., with an offset of 1) and TRP 2 in the fourth RE (e.g., with an offset of 3).

[0120] As another method for orthogonalizing RSs of different TRPs, code division can be used. In other words, different TRPs can transmit RSs at the same time and frequency, but using orthogonal codes for transmission. For example, within a symbol, for corresponding resource blocks (RBs), the first and second REs can be used for DMRS. Other patterns can be used as needed.

[0121] Figure 14 and Figure 15 1 illustrates code division multiplexing (CDM) of RSs for downlink control channels according to some embodiments. Figure 14 As shown, TRP 1 can use mode (1 1) to transmit RS, and Figure 15 As shown, TRP 2 may use pattern (1-1). Based on the orthogonality of these patterns, the UE may be able to receive both the RS from TRP 1 and the RS from TRP 2 and use these RSs to demodulate the control information from TRP 1 and TRP 2. The TRP may transmit control information in REs not used for RS transmission.

[0122] Another method for downlink control channel reliability enhancement may include configuring different transmission configuration indication (TCI) states for different TRPs. In some embodiments, a MAC CE may be used to configure two TTIs for a CORESET PDCCH. For example, a first TRP may transmit a MAC CE to a UE that indicates a first TCI for the first TRP and a second TCI for a second TRP.

[0123] The TCI state may indicate a quasi-co-location (QCL) relationship between one or more of various (e.g., periodic) RSs and control and / or data channels (e.g., PDCCH and / or PDSCH, etc.) that the TRP may use to transmit to the UE. Thus, the UE may use RSs (e.g., based on the QCL of the TCI and the control and / or data channels) to decode DL transmissions from the TRP 501. The TRP 501 may configure any number of TCI states using higher-layer signaling (e.g., radio resource control (RRC)) and (e.g., later) use lower-layer signaling (e.g., downlink control information (DCI)) to select the TCI state to use.

[0124] In some embodiments, multiple TCI code points may be defined and configured by RRC. A TCI code point may include two TCI states, for example, one TCI state for each of two TRPs. Thus, in response to an indication of a TCI code point with two TCI states (e.g., in a DCI or MAC CE), the UE may use a first TCI state for the first TRP and a second TCI state for the second TRP. It should be understood that a TCI code point with one TCI state may be used for a single TRP operation and / or a single DCI operation. In addition, according to some embodiments, a TCI code point with more than two TCI states may be used.

[0125] In some implementations, a MAC CE may indicate two TCI states for the same CORESET. Figure 16A MAC CE with an indication of a second TCI state is shown (e.g., TCI state ID 2 is added). Thus, in response to receiving a MAC CE with two TCI state IDs, the UE may use the first TCI state for the first TRP and the second TCI state for the second TRP. A MAC CE with a single TCI state ID may be used for a single TRP operation and / or a single DCI operation.

[0126] Another method for downlink control channel reliability enhancement may include using a new quasi-co-location (QCL) type to indicate that two RSs are QCLs with respect to Doppler shift or frequency offset. In standard documents (e.g., 3GPP Release 15), the following four QCL types may be previously defined (see, for example, 5.1.5 in 38.214):

[0127] 'QCL-Type A': {Doppler shift, Doppler spread, average delay, delay spread},

[0128] 'QCL-Type B': {Doppler shift, Doppler spread},

[0129] 'QCL-Type C': {Doppler shift, mean delay}, and

[0130] 'QCL-Type D': {spatial Rx parameters}.

[0131] Therefore, in some embodiments, a fifth QCL type (e.g., Type E) may be defined. The fifth type may be described, for example, as:

[0132] 'QCL TypeE': {Doppler shift}

[0133] In other words, the new type can be a standalone QCL based, for example, solely on Doppler shift. This can be contrasted with current QCL types, which can bundle Doppler shift with other properties (e.g., Doppler spread in the case of QCL-type B).

[0134] In some embodiments, the control information data transmitted from the TRPs (e.g., associated with the RSs) may be the same. For example, a first TRP may transmit first control information to a UE during a timeslot / CORESET. During the same timeslot / CORESET (e.g., using any of the orthogonalization techniques discussed above), a second TRP may transmit second control information to the UE. The second control information may be a copy of the first control information. The first control information may be demodulated using the RS from the first TRP, and the second control information may be demodulated using the RS from the second TRP. The UE may combine these channels before decoding the control information. In other words, the UE may rely on both the first control information and the second control information (e.g., a copy of the first control information) to determine the content of the first control information / second control information.

[0135] Uplink RS enhancement

[0136] Sounding Reference Signals (SRS) and / or other uplink RSs may be enhanced to support uplink transmissions to the network. For example, uplink RSs may be used by the network to determine UE speed and / or for channel estimation and / or to correct for UE motion.

[0137] In some embodiments, a MAC CE may be used to update the configuration for a periodic SRS (P-SRS). For example, a MAC CE may be used to indicate which path loss RS may be used by the UE in order to estimate the path loss between the UE and the TRP for determining the transmission power of the P-SRS based on open-loop power control. The same MAC CE or different MAC CEs may be used to indicate the spatial relationship to be used for transmitting the uplink RS (e.g., the uplink beam of the UE). The MAC CE may indicate multiple spatial relationships (e.g., similar to the discussion of a MAC CE directly indicating multiple TCI states or indicating a TCI code point with multiple TCIs). For example, the MAC CE may directly indicate multiple spatial relationships, or may indicate a spatial relationship code point that defines multiple spatial relationships. Thus, the UE may use multiple spatial relationships to transmit the RS. The multiple spatial relationships may correspond to multiple TRPs (e.g., a first spatial relationship with a first TRP, etc.). The network may use the RS received at the corresponding TRP to estimate the channel between the UE and the corresponding TRP and / or demodulate the uplink transmission from the UE to the corresponding TRP. Using MAC CE to update the configuration of uplink RS (eg, including the spatial relationship) may be faster than using RRC to update the configuration. According to some embodiments, DCI may be used to update the configuration of uplink RS.

[0138] In some embodiments, the spatial relationship definition can be extended to include frequency offsets. Thus, based on one or more configured spatial relationships, the UE can transmit an SRS or other uplink RS based on a frequency offset estimated from the spatial relationship RS. In some embodiments, the spatial relationship RS can be configured as a downlink RS (e.g., CSI-RS or SSB), an uplink RS (e.g., SRS), or both a downlink RS and an uplink RS. In other words, the UE can offset the frequency of the uplink RS it transmits by the frequency offset of the spatial relationship. Thus, the UE can "pre-correct" the uplink RS for Doppler shift associated with the UE's motion. Different frequency offsets can be used for different spatial relationships. For example, the UE can use a first spatial relationship with a first offset to transmit to a first TRP and a second spatial relationship with a second offset to transmit to a second TRP. The frequency offset can be determined in various ways. For example, the network can determine one or more frequency offsets (e.g., based on measurements of previous uplink RSs from the UE, data reported from the UE, or other knowledge of the UE's motion) and can indicate the frequency offset to be used for one or more spatial relationships for the UE. As another example, the UE may determine the frequency offset of the spatial relationship (e.g., based on measurements of the downlink RS or other knowledge of the UE's motion). In some embodiments, the frequency offset of one spatial relationship may be determined based on the frequency offset of another spatial relationship. For example, if the frequency offset of a TRP in front of the UE (e.g., in the direction of travel of the UE) is known, the frequency offset of another TRP behind the UE may be determined by inverting the sign of the frequency offset (e.g., multiplying by -1).

[0139] In some embodiments, the UE may transmit SRS or other uplink RS based on an absolute channel number (e.g., a frequency without offset, e.g., as determined by a lower layer (e.g., Layer 1)) regardless of the estimated frequency offset. In other words, the uplink RS may be transmitted without any frequency correction (performed by the UE) for the motion of the UE. On the receiver side, the TRP may estimate the UE frequency offset due to the UE motion based on the SRS. Based on the UE frequency offset estimate, the TRP may correct for the motion of the UE. For example, according to some embodiments, the TRP may apply an offset (e.g., opposite) frequency offset during transmission to the UE, e.g., so that the received signal on the UE side is not affected by the UE motion.

[0140] In some embodiments, a Tracking RS (TRS) may be configured in a spatial relationship to a Semi-Periodic (SP) SRS, an Aperiodic (AP) SRS, and / or a P-SRS. For example, a UE may estimate a frequency offset based on the configured TRS, and the frequency offset may be used to determine the UL transmission frequency of the P / SP / AP-SRS to which the TRS is configured in spatial relationship.

[0141] New communication mode in case of fast traveling UE

[0142] A new mode of operation can be configured for use by the network and UE when the UE is traveling rapidly. For example, among other possibilities, this mode can be referred to as High Speed Train (HST) mode. This mode can be used for single DCI multiple TRP operation. For example, Release 16 single DCI multiple TRP operation can be enhanced to support high speeds, such as UEs on HST. In other words, a special mode of single DCI multiple TRP operation can be configured.

[0143] In some embodiments, in this new mode, the TCI codepoints configured by the RRC may include two TCI states. For example, as discussed above, one TCI state may be used to communicate with one TRP, while another TCI state may be used to communicate with another TRP. For example, the UE may transmit an uplink RS based on the TCI state, and / or the network may transmit a downlink RS to the UE based on the TCI state.

[0144] In some embodiments, in the new mode, QCLs and / or spatial relationships can be configured for multiple TRPs.

[0145] In some embodiments, in the new mode, various adaptations among those discussed above may be applied by the UE and / or the network / TRP.

[0146] In some embodiments, in the new mode, one of the TRPs may provide DCI for uplink and downlink communications with both TRPs.

[0147] The new mode may be entered (e.g., by the UE and / or the network / TRP) when one or more of the following conditions are true:

[0148] The first condition may include that repetitionScheme-r16 is not configured by RRC. In other words, according to some embodiments, the first condition may include that none of the following single DCI multi-TRP modes are configured: (1) FDM Scheme A, (2) FDM Scheme B, and / or (3) TDM Scheme A.

[0149] The second condition may include at least one of the following conditions: repetitionNumber-r16 is not configured in any entry in PDSCH-TimeDomainResourceAllocation and / or repetitionNumber-r16 is not indicated in the DCI field time domain resource assignment. In other words, single DCI multiple TRP scheme 4 or inter-time slot TDM scheme is not configurable.

[0150] If both of the above conditions are true, and one or three CDM groups are indicated in the DCI antenna port field, the network and / or UE may treat these conditions as implicit indications to operate according to the new operating mode. For example, the third condition may include configuring one or three CDM groups.

[0151] Alternatively, the network may explicitly configure (eg, by RRC and / or MAC CE) the new operating mode.

[0152] Based on the implicit or explicit indication, the UE and the network may operate according to the new mode, for example until conditions change or an explicit indication to change mode is sent.

[0153] In some embodiments, an additional condition for entering a new mode may be that the UE is moving rapidly (e.g., above a threshold speed). Thus, if the UE is not moving rapidly enough, the UE may not enter the new mode. The motion / speed may be determined based on various means, including but not limited to radio measurements, GNSS, motion sensors, etc.

[0154] In some embodiments, a frequency offset may be used to correct the Doppler shift of a downlink RS transmitted by one or more TRPs, for example, in a manner similar to that described above for an uplink RS.

[0155] In some embodiments, the UE may determine frequency offset information based on downlink RS from one or more TRPs. The UE may apply the frequency offset information to the transmission of uplink RS to one or more TRPs.

[0156] In some embodiments, the network may determine frequency offset information based on uplink RS from the UE to one or more TRPs. The network may apply the frequency offset information to the transmission of downlink RS from one or more TRPs to the UE.

[0157] In a first set of embodiments, a base station may include: a radio component; and a processor operably connected to the radio component and configured to cause the base station to: transmit a first reference signal (RS) from a first transmission and reception point (TRP) to a user equipment device (UE) during a first symbol; transmit a second RS from a second TRP to the UE during the first symbol; transmit first control information from the first TRP to the UE during the first symbol, wherein the first control information is configured to be demodulated using the first RS; and transmit second control information from the second TRP to the UE during the first symbol, wherein the second control information is configured to be demodulated using the second RS.

[0158] In some implementations, the first RS and the second RS may be transmitted at multiple resource elements during the first symbol, where the resource elements on which the second RS is transmitted are offset relative to the resource elements on which the first RS is transmitted.

[0159] In some embodiments, the first RS and the second RS may be transmitted at multiple resource elements during the first symbol, where the resource elements on which the second RS is transmitted are the same as the resource elements on which the first RS is transmitted, and where the first RS and the second RS are orthogonalized using code division multiplexing.

[0160] In some embodiments, the processor may be further configured to cause the base station to: transmit control information from the first TRP to the UE, the control information comprising a transmission configuration indication (TCI) code point, wherein the TCI code point indicates a first TCI state and a second TCI state, wherein the first RS is transmitted according to the first TCI state, and the second RS is transmitted according to the second TCI state.

[0161] In some embodiments, the processor may be further configured to cause the base station to: transmit control information from the first TRP to the UE, the control information comprising a medium access control (MAC) control element (CE), wherein the MAC CE indicates a first transmission configuration indication (TCI) state and a second TCI state of a first control resource set (CORESET), wherein the first RS is transmitted according to the first TCI state, and the second RS is transmitted according to the second TCI state, wherein the first symbol is associated with the first CORESET.

[0162] In some embodiments, the processor may be further configured to cause the base station to: transmit control information from the first TRP to the UE, the control information including an indication that the first RS and the third RS are quasi-co-located with respect to at least one of Doppler shift or frequency offset.

[0163] In some embodiments, the control information may further include an indication that the second RS and the fourth RS are quasi-co-located with respect to at least one of Doppler shift or frequency offset.

[0164] In some embodiments, the processor may be further configured to cause the base station to: transmit control information from the first TRP to the UE, the control information including a medium access control (MAC) control element (CE), wherein the MAC CE indicates to the UE a configuration to update the periodic sounding RS; and receive the periodic sounding RS from the UE at the first TRP and the second TRP according to the configuration.

[0165] In a second group of embodiments, a device may include: a processor configured to enable a base station of a cellular network to: establish communication with a UE via a first transmission and reception point (TRP); transmit a medium access control (MAC) control element (CE) to the UE from the first TRP, wherein the MAC CE includes an indication of using multiple spatial relationships to transmit an uplink periodic reference signal (RS); receive the uplink RS from the UE via the first TRP according to a first spatial relationship among the multiple spatial relationships; and receive the uplink RS from the UE via the second TRP according to a second spatial relationship among the multiple spatial relationships.

[0166] In some embodiments, the uplink periodic RS may be a sounding RS.

[0167] In some embodiments, the MAC CE also includes an indication of a path loss RS for uplink power control of the uplink periodic RS.

[0168] In some embodiments, the first spatial relationship may include a first frequency offset.

[0169] In some embodiments, the second spatial relationship can include a second frequency offset that is different from the first frequency offset.

[0170] In some embodiments, the processor may be further configured to cause the base station to determine that the UE is moving rapidly between the first TRP and the second TRP, wherein the transmission of the MAC CE is in response to the determination.

[0171] In some embodiments, the processor may be further configured to cause the base station to compensate for a Doppler drift of the uplink RS, wherein the Doppler drift of the uplink RS received via the first TRP is different from the Doppler drift of the uplink RS received via the second TRP.

[0172] In a third set of embodiments, a method may include: at a cellular network, establishing communication with a user equipment device (UE); determining that the UE is rapidly moving between a first transmission and reception point (TRP) and a second TRP; in response to the determination: causing the first TRP to transmit a first demodulation reference signal (DMRS) to the UE on a first time / frequency resource, wherein the first time / frequency resource is within a first time slot, wherein the first DMRS is UE-specific; and causing the second TRP to transmit a second DMRS to the UE on a second time / frequency resource, wherein the second time / frequency resource is within the first time slot and different from the first time / frequency resource, wherein the second DMRS is UE-specific; causing the first TRP to transmit first data to the UE to be demodulated using the first DMRS; and causing the second TRP to transmit second data to the UE to be demodulated using the second DMRS.

[0173] In some embodiments, the first time / frequency resource is a time / frequency resource associated with a DMRS transmitted to a UE that is not determined to be moving rapidly.

[0174] In some embodiments, the method may also include: causing at least one of the first TRP or the second TRP to transmit an indication of the second time / frequency resource to the UE.

[0175] In some embodiments, the indication may include an indication of an offset of the second time / frequency resource relative to the first time / frequency resource.

[0176] In some embodiments, the method may further include: splitting the time / frequency resources associated with the DMRS transmitted to the UE that is not determined to be moving fast, wherein the second time / frequency resources and the first time / frequency resources are separate subsets of the time / frequency resources associated with the DMRS transmitted to the UE that is not determined to be moving fast.

[0177] In some embodiments, the first time / frequency resource may be associated with a first code division multiplexing (CDM) group and the second time / frequency resource may be associated with a second CDM group.

[0178] In a fourth group of embodiments, a user equipment device (UE) may include: a radio component; and a processor operably connected to the radio component and configured to cause the UE to: determine: the UE is moving rapidly between a first transmission and reception point (TRP) and a second TRP; a repetition scheme is not configured; and 1 or 3 code division multiplexing groups are indicated in the antenna port field; and in response to the determination, enter a first operating mode, wherein the first operating mode is associated with high-speed travel.

[0179] In some embodiments, the first operating mode may include a single downlink control information (DCI) multi-TRP mode.

[0180] In some embodiments, according to the first mode, a transmission configuration indication (TCI) code point may be configured, wherein the TCI code point indicates a first TCI state and a second TCI state.

[0181] In some embodiments, the processor may be further configured to cause the UE to: receive a first reference signal (RS) from the first TRP according to the first TCI state; and receive a second RS from the second TRP according to the second TCI state.

[0182] In some embodiments, the first RS may be a channel state information RS, wherein the first RS is received during a first symbol, wherein the processor may be further configured to cause the UE to: receive control information from the first TRP during the first symbol; and demodulate the control information using the first RS.

[0183] In some embodiments, the processor may be further configured to cause the UE to: transmit a first reference signal (RS) to the first TRP based on the first TCI state; and transmit a second RS to the second TRP based on the second TCI state.

[0184] In some embodiments, the processor may be further configured to cause the UE to perform uplink transmissions to the first TRP and to the second TRP according to the first mode.

[0185] In a fifth group of embodiments, an apparatus may include: a processor configured to enable a user equipment device (UE): establish communication with a first transmission and reception point (TRP) of a network; receive a medium access control (MAC) control element (CE) from the first TRP, wherein the MAC CE includes an indication of using multiple spatial relationships to transmit an uplink periodic reference signal (RS); transmit the uplink RS to the first TRP according to a first spatial relationship among the multiple spatial relationships; and transmit the uplink RS to the second TRP according to a second spatial relationship among the multiple spatial relationships.

[0186] In some embodiments, the processor may be a baseband processor.

[0187] In some embodiments, the uplink periodic RS may be a sounding RS.

[0188] In some embodiments, the MAC CE includes an indication of a path loss RS for uplink power control of the uplink periodic RS.

[0189] In some embodiments, transmitting the uplink RS to the first TRP may include performing uplink power control based on a path loss RS from the first TRP.

[0190] In some embodiments, transmitting the uplink RS to the second TRP may include performing uplink power control based on a path loss RS from the second TRP.

[0191] In some embodiments, the first spatial relationship may include a first frequency offset.

[0192] In some embodiments, the second spatial relationship can include a second frequency offset that is different from the first frequency offset.

[0193] In some embodiments, transmitting the uplink RS according to the first spatial relationship may correct the uplink RS for the motion of the UE.

[0194] In some embodiments, transmitting the uplink RS may be based on a channel number without a frequency offset.

[0195] In a sixth set of embodiments, a method may include: at a user equipment device (UE): establishing communication with a cellular network; receiving a first downlink reference signal (RS) from a first transmission and reception point (TRP) of the cellular network; receiving a second downlink RS from a second TRP of the cellular network, wherein the second downlink RS is orthogonal to the first downlink RS; communicating with the first TRP and the second TRP simultaneously, wherein the communication includes: receiving a first downlink signal from the first TRP; demodulating the first downlink signal using the first downlink RS; receiving a second downlink signal from the second TRP; and demodulating the second downlink signal using the second downlink RS.

[0196] In some embodiments, the first downlink RS and the second downlink RS may be time division multiplexed, wherein the first downlink signal and the second downlink signal may be data communications.

[0197] In some implementations, the first downlink RS and the second downlink RS may be received according to different antenna ports.

[0198] In some implementations, the first downlink RS and the second downlink RS may be code division multiplexed.

[0199] In some implementations, the first downlink RS and the second downlink RS may be frequency division multiplexed.

[0200] In some embodiments, the method may further include: determining frequency offset information based on the first downlink RS; and applying the frequency offset information to a first uplink RS transmitted to the first TRP.

[0201] In various embodiments, various combinations of the above adjustments may be performed together. For example, the network may send control information to the UE to cause the UE to process the downlink RS according to the above embodiments and transmit the uplink RS according to the above embodiments.

[0202] Yet another example embodiment may include a method comprising: performing, by a wireless device: any or all of the foregoing examples.

[0203] Another example embodiment may include a wireless device comprising: an antenna; a radio coupled to the antenna; and a processing element operatively coupled to the radio, wherein the device is configured to implement any or all of the foregoing examples.

[0204] Another example embodiment may include an apparatus comprising a processing element configured to cause a wireless device to implement any or all of the foregoing examples.

[0205] Another exemplary set of embodiments may include a non-transitory computer-accessible memory medium including program instructions that, when executed at a device, cause the device to implement any or all portions of any of the foregoing examples.

[0206] Another exemplary set of embodiments may include a computer program comprising instructions for performing any or all portions of any of the foregoing examples.

[0207] Another exemplary set of embodiments may include an apparatus comprising means for performing any or all of the elements of any of the preceding examples.

[0208] By interpreting each message / signal X received by a 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 of the methods for operating a UE described herein may become the basis for the corresponding method for operating a base station.

[0209] In addition to the exemplary embodiments described above, further embodiments of the present 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.

[0210] In some embodiments, a non-transitory computer-readable storage medium may be configured such that it stores program instructions and / or data, wherein the program instructions, if executed by a computer system, cause the computer system to perform a method, such as any one of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein or any combination of such subsets.

[0211] In some embodiments, a device (e.g., UE 106 or 107) may be configured to include a processor (or a group of processors) and a memory medium, wherein the memory medium stores program instructions, wherein the processor is configured to read and execute the program instructions from the memory medium, wherein the program instructions may be executed to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any method embodiments described herein, or any combination of such subsets). The device may be implemented in any of various forms.

[0212] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining 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 stated to users.

[0213] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to encompass all such variations and modifications.

Claims

1. A method for wireless communication, comprising: transmitting a medium access control (MAC) control element (CE) from a first transmission and reception point (TRP) to a user equipment device (UE), the MAC CE indicating a first transmission configuration indication (TCI) state and a second TCI state for a first control resource set (CORESET); transmitting first control information in a first physical downlink control channel (PDCCH) transmission from the first TRP to the UE during a first symbol in the first CORESET according to the first TCI state; as well as Second control information is transmitted in a second PDCCH transmission from a second TRP to the UE during the first symbol in the first CORESET according to the second TCI state, wherein the second control information is a copy of the first control information.

2. The method according to claim 1, wherein the first control information is configured to be demodulated using a first reference signal (RS) during the first symbol; and The second control information is configured to be demodulated using a second RS. The method according to claim 1 , wherein the first control information comprises a first PDCCH message. The method according to claim 3 , wherein the second control information comprises a second PDCCH message.

5. The method according to claim 1, wherein the MAC CE comprises: Serving cell identifier; as well as The identifier of the first CORESET.

6. The method according to claim 1, wherein the MAC CE comprises: an identifier of the first TCI state; as well as An identifier of the second TCI state.

7. An apparatus for wireless communication, the apparatus comprising a processor configured to cause a base station to perform the method according to any one of claims 1 to 6. 8 . A non-transitory computer-readable medium comprising program instructions configured to cause a base station to execute the method according to claim 1 .

9. A base station, comprising: radio components; as well as A processor operatively coupled to the radio component and configured to cause the base station to perform the method according to any one of claims 1 to 6.

10. A method for wireless communication, comprising: receiving a medium access control (MAC) control element (CE) from a first transmission and reception point (TRP), the MAC CE indicating a first transmission configuration indication (TCI) state and a second TCI state for a first control resource set (CORESET); receiving first control information in a first physical downlink control channel (PDCCH) transmission from the first TRP during a first symbol in the first CORESET according to the first TCI state; as well as Second control information is received in a second PDCCH transmission from a second TRP during the first symbol in the first CORESET according to the second TCI state, wherein the second control information is a copy of the first control information.

11. The method of claim 10, wherein the first control information is configured to be demodulated using a first reference signal (RS) during the first symbol; and The second control information is configured to be demodulated using a second RS. The method according to claim 10 , wherein the first control information comprises a first PDCCH message. The method according to claim 12 , wherein the second control information comprises a second PDCCH message.

14. The method according to claim 10, wherein the MAC CE comprises: Serving cell identifier; as well as The identifier of the first CORESET.

15. The method according to claim 10, wherein the MAC CE comprises: an identifier of the first TCI state; and An identifier of the second TCI state.

16. An apparatus for wireless communication, the apparatus comprising a processor configured to cause a user equipment to perform the method according to any one of claims 10 to 15. 17 . A non-transitory computer-readable medium comprising program instructions configured to cause a user equipment to perform the method according to claim 10 .

18. A user equipment comprising: radio components; as well as A processor operatively coupled to the radio and configured to cause the user equipment to perform the method according to any one of claims 10 to 15.

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