Methods and apparatus for phase offset reporting for multiple transmission / reception point (MTRP) operation

Abstract

Methods and devices for User Equipment (UE) reporting of phase offsets from signals transmitted from different Transmission / Reception Points (TRPs) are disclosed. The method includes a UE receiving a first CSI-Reference Signal (CSI-RS) from a first TRP and measuring a first phase associated with the first CSI-RS. The method also includes receiving a second CSI-RS from a second TRP and measuring a second phase associated with the second CSI-RS. The UE transmits a CSI report to the first TRP or the second TRP that includes a first phase offset based on the first phase and the second phase, an indication identifying the second TRP, and an indication of a frequency domain subband for the first phase offset. Channel Measurement Resource (CMR) configurations for measuring and reporting phase offsets are also disclosed.

Description

Atty Dkt. P68852WO1 (1784-0070WO1) TITLE: Methods and Apparatus for Phase Offset Reporting for Multiple Transmission / Reception Point (mTRP) Operation FIELD

[0001] The present application relates to wireless devices and wireless networks including devices, computer-readable media, and methods for reporting phase offsets from different Transmission / Reception Points (TRPs). BACKGROUND

[0002] Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS) and are capable of operating sophisticated applications that utilize these functionalities. Additionally, there exist numerous different wireless communication technologies and standards. Some examples of wireless communication standards include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), IEEE 802.11 (WLAN or Wi-Fi), BLUETOOTHTM, 5G New Radio (NR), etc.

[0003] Multiple TRP (mTRP) operation has been introduced in 5G NR. In the first 5G NR Release 15, mTRP operation was supported in a transparent mode. Following Release 15, 5G NR began to support explicit mTRP operation. For example, Release 16 supported five different single-Downlink Control Information (sDCI) mTRP Non-Coherent Joint Transmission (NCJT) schemes for a Physical Downlink Shared Channel (PDSCH): a Spatial Domain Multiplex (SDM) scheme, two Frequency Domain Multiplex (FDM) schemes, and two Time Domain Multiplex (TDM) schemes. Release 16 also introduced multiple DCI (mDCI) mTRP schemes for both a PDSCH and a Physical Uplink Shared Channel (PUSCH).

[0004] Release 17 introduced a sDCI mTRP TDM scheme for a PUSCH and a Physical Uplink Control Channel (PUCCH). For a Physical Downlink Control Channel (PDCCH), two single frequency network (SFN) schemes and a PDCCH repetition scheme was introduced. For a PDSCH, two SFP schemes were introduced.Atty Dkt. P68852WO1 (1784-0070WO1)

[0005] Release 18 introduced a sDCI mTRP Coherent Joint Transmission (CJT) scheme for a PDSCH. For a PUSCH, three Simultaneous Transmission across Multiple Panels (STxMP) schemes were introduced: a sDCI SFN scheme, a sDCI SDM scheme, and a mDCI scheme. A sDCI SFN STxMP scheme was also introduced for a PUCCH. SUMMARY

[0006] In general, embodiments disclosed herein are directed to methods and devices for reporting phase offsets from signals transmitted from different TRPs. Such phase offsets may provide information that can be used to perform mTRP CJT. Communication using mTRP CJT may achieve better performance in comparison to Non-coherent Joint Transmission (NCJT), provided the coherency can be maintained between the antenna elements from the different TRPs. Embodiments are directed to measuring a phase offset and reporting the phase offset in a Channel State Indicator (CSI) report. Embodiments also address Channel Measurement Resource (CMR) configurations for measuring and reporting phase offsets.

[0007] In one aspect, embodiments are directed to a method performed by a User Equipment (UE) that includes receiving a first CSI-Reference Signal (CSI-RS) from a first TRP and measuring a first phase associated with the first CSI-RS. The method also includes receiving a second CSI-RS from a second TRP and measuring a second phase associated with the second CSI- RS. The UE transmits a CSI report to the first TRP or the second TRP that includes a first phase offset based on the first phase and the second phase, an indication identifying the second TRP, and an indication of a frequency domain subband for the first phase offset.

[0008] In one example, the first CSI-RS and the second CSI-RS are within a first frequency domain subband. In another example, the first TRP is a reference TRP, and the first phase offset is the difference of the second phase minus the first phase from the reference TRP. The UE may determine that the first TRP is the reference TRP based on a resource identification number of a first CSI-RS resource from the first TRP. The UE may also determine the first TRP is the reference TRP because a first CSI-RS resource from the first TRP is the first CSI-RS resource listed on a list of CSI-RS resources configured as a Channel Measurement Resource (CMR). The CSI report may further include an indication that the first TRP is the reference TRP. The first TRP may be the reference TRP for two or more frequency domain subbands.

[0009] In an example, the CSI report may include an indication that one or more frequency domain subbands are invalid. The CSI report may also include an indication that one or moreAtty Dkt. P68852WO1 (1784-0070WO1) TRPs are invalid.

[0010] In some examples, the frequency domain subband is one of a plurality of equally-sized frequency domain subbands distributed across an active downlink (DL) bandwidth part (BWP), and the size of the frequency domain subband is a determined number of physical resource blocks (PRBs). The plurality of frequency domain subbands may include a single frequency domain subband with less PRBs than the remaining equally-sized frequency domain subbands. The start of the plurality of frequency domain subbands may be determined from a common resource block (CRB), for example, CRB 0.

[0011] In some examples, the UE may receive an indication of a subset of a plurality of frequency domain subbands, and the CSI report will include phase information for each of the frequency domain subbands in the subset. For example, the indication may be a bitmap representing the plurality of frequency domain subbands.

[0012] In an example, the UE transmits, to either the first TRP or the second TRP, a UE capability message that includes a maximum number of frequency domain subbands for reporting the phase information.

[0013] In an example, the first CSI-RS is within a first frequency domain subband and the second CSI-RS is within a second frequency domain subband. In another example, an indication of a phase offset associated with the first CSI-RS is not included in the CSI report. In another example, the first phase offset for the second CSI-RS is quantized based on a linear approximation and an index of the frequency domain subband. In another example, the first phase offset for the second CSI-RS is quantized based on a spatially uniform equal distance approximation.

[0014] In another example, the UE may receive a third CSI-RS from a third TRP and measure a third phase associated with the third CSI-RS. The CSI report may further include a second phase offset based on the first phase and the third phase, an indication identifying the third TRP, and an indication of the frequency domain subband for the second phase offset.

[0015] The UE may further receive a fourth CSI-RS from a fourth TRP and measuring a fourth phase associated with the fourth CSI-RS. The CSI report may further include a third phase offset based on the first phase and the fourth phase, an indication identifying the fourth TRP, and an indication of the frequency domain subband for the third phase offset.

[0016] In another aspect, embodiments are directed to a method performed by a UE that includes the UE receiving a first Tracking Reference Signal (TRS) from a first TRP and measuringAtty Dkt. P68852WO1 (1784-0070WO1) a first phase associated with the first TRS. The UE receives a second TRS from a second TRP and measures a second phase associated with the second TRS. The UE transmits a CSI report to the first TRP or the second TRP that includes a phase offset based on the first phase and the second phase, an indication identifying the second TRP, and an indication of a frequency domain subband for the phase offset.

[0017] The method may also include the UE receiving from the first TRP an indication of a CSI-RS resource set including the first TRS. In some examples, each TRP transmits an associated TRS. In some examples, the first TRS is transmitted periodically.

[0018] In some examples, the UE may receive from the first TRP a message including an indication of a CSI-RS resource set for the first TRP. The first TRS being one of a plurality of resources included in the CSI-RS resource set. The message may further include quasi co-location information for a Transmission Configuration Indicator (TCI) state for the second TRP.

[0019] In one example, the UE transmits to the network a UE capability message that includes a minimum or a maximum frequency domain density of the CSI-RS resource for reporting phase information.

[0020] The techniques described herein may be implemented in and / or used with a number of different types of devices, including but not limited to cellular phones, wireless devices, tablet computers, wearable computing devices, portable media players, baseband processors, non- transitory computer readable mediums, and any of various other computing devices.

[0021] This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are merely examples and should not be construed to narrow 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, Figures, and Claims. BRIEF DESCRIPTION OF DRAWINGS

[0022] A better understanding of the present subject matter can be obtained when the following detailed description of various aspects is considered in conjunction with the following drawings.Atty Dkt. P68852WO1 (1784-0070WO1)

[0023] Figure 1 illustrates an example wireless communication system, according to some aspects.

[0024] Figure 2 illustrates an example block diagram of a UE, according to some aspects.

[0025] Figure 3 illustrates a base station (BS) in communication with a UE device, according to some aspects.

[0026] Figure 4A illustrates a system, according to some aspects.

[0027] Figure 4B illustrates a frequency range, according to some aspects.

[0028] Figure 5 illustrates a method, according to some aspects.

[0029] Figures 6A and 6B illustrate different options for distributing frequency domain subbands across an active DL BWP, according to some aspects.

[0030] While the features described herein may be susceptible to various modifications and alternative forms, specific aspects thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims. DETAILED DESCRIPTION

[0031] Coherent Joint Transmission (CJT) using multiple TRPs has the potential to achieve high performance provided the coherency can be maintained between the antenna elements from different TRPs. In practice, different TRPs can experience a different time and frequency offset and / or drift in view of the location and movement of the UE, the hardware implementation of in each TRP, and / or environmental conditions, etc. To achieve mTRP CJT, the UE may estimate the time, frequency, and / or phase offsets measured between signals transmitted from different TRPs. Such an enhancement of the UE reporting may be used for a CJT deployment under non- ideal synchronization and backhaul environments for both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) transmissions.

[0032] Embodiments disclosed herein provide a detailed design for measuring offsets and reporting the offsets, as well as CMR configurations that may be used to measure and report theAtty Dkt. P68852WO1 (1784-0070WO1) offsets.

[0033] The following is a glossary of terms that may be used in this disclosure:

[0034] Memory Medium – Any of various types of non-transitory memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD- ROM, floppy disks, or tape device; a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash, magnetic media, e.g., a hard drive, or optical storage; registers, or other similar types of memory elements, etc. The memory medium may include other types of non-transitory memory as well or combinations thereof. In addition, the memory medium may be located in a first computer system in which the programs are executed or may be located in a second different computer system which connects to the first computer system over a network, such as the Internet. In the latter instance, the second computer system may provide program instructions to the first computer for execution. The term “memory medium” may include two or more memory mediums which may reside in different locations, e.g., in different computer systems that are connected over a network. The memory medium may store program instructions (e.g., embodied as computer programs) that may be executed by one or more processors.

[0035] Carrier Medium – a memory medium as described above, as well as a physical transmission medium, such as a bus, network, and / or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

[0036] Programmable Hardware Element - includes various hardware devices comprising multiple programmable function blocks connected via a programmable interconnect. Examples include FPGAs (Field Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs (Field Programmable Object Arrays), and CPLDs (Complex PLDs). The programmable function blocks may range from fine grained (combinatorial logic or look up tables) to coarse grained (arithmetic logic units or processor cores). A programmable hardware element may also be referred to as “reconfigurable logic.”

[0037] 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 combinations of devices. In general, the term “computer system” can be broadly defined to encompass any device (or combination of devices) having at least oneAtty Dkt. P68852WO1 (1784-0070WO1) processor that executes instructions from a memory medium.

[0038] User Equipment (UE) (also “User Device” or “UE Device”) – any of various types of computer systems or devices that are mobile or portable and that perform wireless communications. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone™, Android™-based phones), portable gaming devices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™, iPhone™), laptops, wearable devices (e.g., smart watch, smart glasses), PDAs, portable Internet devices, music players, data storage devices, other handheld devices, in-vehicle infotainment (IVI), in-car entertainment (ICE) devices, an instrument cluster, head-up display (HUD) devices, onboard diagnostic (OBD) devices, dashtop mobile equipment (DME), mobile data terminals (MDTs), Electronic Engine Management System (EEMS), electronic / engine control units (ECUs), electronic / engine control modules (ECMs), embedded systems, microcontrollers, control modules, engine management systems (EMS), networked or “smart” appliances, machine type communications (MTC) devices, machine-to-machine (M2M), internet of things (IoT) devices, etc. In general, the term “UE” or “UE device” can be broadly defined to encompass any electronic, computing, and / or telecommunications device (or combination of devices) which is transportable by a user and capable of wireless communication.

[0039] Wireless Device – any of various types of computer systems or devices that perform wireless communications. A wireless device can be portable (or mobile) or may be stationary or fixed at a certain location. A UE is an example of a wireless device.

[0040] Communication Device – any of various types of computer systems or devices that perform communications, where the communications can be wired or wireless. A communication device can be portable (or mobile) or may be stationary or fixed at a certain location. A wireless device is an example of a communication device. A UE is another example of a communication device.

[0041] Base Station – The term “base station” or “wireless station” has the full breadth of its ordinary meaning, and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system. For example, if the base station is implemented in the context of LTE, it may alternately be referred to as an ‘eNodeB’ or ‘eNB.’ If the base station is implemented in the context of 5G NR, it may alternately be referred to as a ‘gNodeB’ or ‘gNB’. Although certain aspects are described in the context of LTE or 5G NR, references to “eNB,” “gNB,” “nodeB,” “base station,” “NB,” etc., mayAtty Dkt. P68852WO1 (1784-0070WO1) refer to one or more wireless nodes that service a cell to provide a wireless connection between user devices and a wider network generally and that the concepts discussed are not limited to any particular wireless technology. Although certain aspects are described in the context of LTE or 5G NR, references to “eNB,” “gNB,” “nodeB,” “base station,” “NB,” etc., are not intended to limit the concepts discussed herein to any particular wireless technology and the concepts discussed may be applied in any wireless system.

[0042] Node – The term “node,” or “wireless node” as used herein, may refer to one more apparatus associated with a cell that provide a wireless connection between user devices and a wired network generally.

[0043] Processing Element (or Processor) – refers to various elements or combinations of elements that are capable of performing a function in a device, such as a user equipment or a cellular network device. Processing elements may include, for example: processors and associated memory, portions or circuits of individual processor cores, entire processor cores, individual processors, processor arrays, circuits such as an ASIC (Application Specific Integrated Circuit), programmable hardware elements such as a field programmable gate array (FPGA), as well any of various combinations of the above.

[0044] Channel - a medium used to convey information from a sender (transmitter) to a receiver. It should be noted that since characteristics of the term “channel” may differ according to different wireless protocols, the term “channel” as used herein may be considered as being used in a manner that is consistent with the standard of the type of device with reference to which the term is used. In some standards, channel widths may be variable (e.g., depending on device capability, band conditions, etc.). For example, LTE may support scalable channel bandwidths from 1.4 MHz to 20MHz. In contrast, WLAN channels may be 22MHz wide while Bluetooth channels may be 1Mhz wide. Other protocols and standards may include different definitions of channels. Furthermore, some standards may define and use multiple types of channels, e.g., different channels for uplink or downlink and / or different channels for different uses such as data, control information, etc.

[0045] Band - The term “band” has the full breadth of its ordinary meaning, and at least includes a section of spectrum (e.g., radio frequency spectrum) in which channels are used or set aside for the same purpose.

[0046] Automatically – refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuitry, programmable hardwareAtty Dkt. P68852WO1 (1784-0070WO1) elements, ASICs, etc.), without user input directly specifying or performing the action or operation. Thus, the term “automatically” is in contrast to an operation being manually performed or specified by the user, where the user provides input to directly perform the operation. An automatic procedure may be initiated by input provided by the user, but the subsequent actions that are performed “automatically” are not specified by the user, i.e., are not performed “manually,” where the user specifies each action to perform. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting check boxes, radio selections, etc.) is filling out the form manually, even though the computer system must update the form in response to the user actions. The form may be automatically filled out by the computer system where the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user input specifying the answers to the fields. As indicated above, the user may invoke the automatic filling of the form but is not involved in the actual filling of the form (e.g., the user is not manually specifying answers to fields but rather they are being automatically completed). The present specification provides various examples of operations being automatically performed in response to actions the user has taken.

[0047] Approximately - refers to a value that is almost correct or exact. For example, approximately may refer to a value that is within 1 to 10 percent of the exact (or desired) value. It should be noted, however, that the actual threshold value (or tolerance) may be application dependent. For example, in some aspects, “approximately” may mean within 0.1% of some specified or desired value, while in various other aspects, the threshold may be, for example, 2%, 3%, 5%, and so forth, as desired, or as required by the particular application.

[0048] Concurrent – refers to parallel execution or performance, where tasks, processes, or programs are performed in an at least partially overlapping manner. For example, concurrency may be implemented using “strong” or strict parallelism, where tasks are performed (at least partially) in parallel on respective computational elements, or using “weak parallelism,” where the tasks are performed in an interleaved manner, e.g., by time multiplexing of execution threads.

[0049] Configured to - Various components may be described as “configured to” perform a task or tasks. In such contexts, “configured to” is a broad recitation generally meaning “having structure that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently performing that task (e.g., a set of electrical conductors may be configured to electrically connect a module to anotherAtty Dkt. P68852WO1 (1784-0070WO1) module, even when the two modules are not connected). In some contexts, “configured to” may be a broad recitation of structure generally meaning “having circuitry that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently on. In general, the circuitry that forms the structure corresponding to “configured to” may include hardware circuits.

[0050] Various components may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase “configured to.” Reciting a component that is configured to perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f) interpretation for that component.

[0051] Example Wireless Communication System

[0052] Turning now to Figure 1, a simplified example of a wireless communication system is illustrated, according to some aspects. It is noted that the system of Figure 1 is a non-limiting example of a possible system, and that features of this disclosure may be implemented in any of various systems, as desired.

[0053] As shown, the example wireless communication system includes a base station 102A, which communicates over a transmission medium with one or more user devices 106A and 106B, through 106Z. Each of the user devices may be referred to herein as a “user equipment” (UE). Thus, the user devices 106 are referred to as UEs or UE devices.

[0054] The base station (BS) 102A may be a base transceiver station (BTS) or cell site (e.g., a “cellular base station”) and may include hardware that enables wireless communication with the UEs 106A through 106Z.

[0055] The communication area (or coverage area) of the base station may be referred to as a “cell.” The base station 102A and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000. Note that if the base station 102A is implemented in the context of LTE, it may alternately be referred to as an ‘eNodeB’ or ‘eNB’. Note that if the base station 102A is implemented in the context of 5G NR, it may alternately be referred to as a ‘gNodeB’ or ‘gNB’.

[0056] In some aspects, the UEs 106 may be IoT UEs, which may comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UEAtty Dkt. P68852WO1 (1784-0070WO1) may utilize technologies such as M2M or MTC for exchanging data with an MTC server or device via a public land mobile network (PLMN), proximity service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. As an example, vehicles to everything (V2X) may utilize ProSe features using a PC5 interface for direct communications between devices. The IoT UEs may also execute background applications (e.g., keep-alive messages, status updates, and the like) to facilitate the connections of the IoT network.

[0057] As shown in Figure 1, the UEs 106, such as UE 106A and UE 106B, may directly exchange communication data via a PC5 interface 108A. Also, the UEs 106C, 106N, and 106Z, may collectively exchange communication data via a PC5 interfaces 108B, 108C, and 108D. In general, such PC5 interfaces are referred to as SL connections.

[0058] The PC5 interface 108 may comprise one or more physical channels, including but not limited to a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Broadcast Channel (PSBCH), and a Physical Sidelink Feedback Channel (PSFCH). The PC5 interface 108 may be responsible for direct communication between devices (unicast), group messaging among select devices (groupcast), and broadcast messaging in accordance with embodiments disclosed herein.

[0059] In V2X scenarios, one or more of the base stations 102 may be or act as Road Side Units (RSUs). The term RSU may refer to any transportation infrastructure entity used for V2X communications. An RSU may be implemented in or by a suitable wireless node or a stationary (or relatively stationary) UE, where an RSU implemented in or by a UE , eNB, or by a gNB. For example, an RSU is a computing device coupled with radio frequency circuitry located on a roadside that provides connectivity support to passing vehicle UEs.

[0060] As shown, the base station 102A may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), and / or the Internet, among various possibilities). Thus, the base station 102A may facilitate communication between the user devices and / or between the user devices and the network 100. In particular, the cellular base station 102A may provide UEs 106 with various telecommunication capabilities, such as voice, SMS and / or dataAtty Dkt. P68852WO1 (1784-0070WO1) services.

[0061] Base station 102A and other similar base stations (such as base stations 102B through 102N) operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 106A-106Z and similar devices over a geographic area via one or more cellular communication standards.

[0062] Thus, while base station 102A may act as a “serving cell” for UEs 106A-106Z as illustrated in Figure 1, each UE 106 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which may be provided by base stations 102B-102Z and / or any other base stations), which may be referred to as “neighboring cells.” Such cells may also be capable of facilitating communication between user devices and / or between user devices and the network 100. Such cells may include “macro” cells, “micro” cells, “pico” cells, and / or cells which provide any of various other granularities of service area size. For example, base stations 102A and 102B illustrated in Figure 1 may be macro cells, while base station 102Z may be a micro cell. Other configurations are also possible.

[0063] In some aspects, base station 102A may be a next generation base station, (e.g., a 5G New Radio (5G NR) base station, or “gNB”). In some aspects, a gNB may be connected to a legacy evolved packet core (EPC) network and / or to a NR core (NRC) / 5G core (5GC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs. For example, it may be possible that that the base station 102A and one or more other base stations 102 support joint transmission, such that UE 106 may be able to receive transmissions from multiple base stations (and / or multiple TRPs provided by the same base station). For example, as illustrated in Figure 1, both base station 102A and base station 102C are shown as serving UE 106A.

[0064] Note that a UE 106 may be capable of communicating using multiple wireless communication standards. For example, the UE 106 may be configured to communicate using a wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, and the like) in addition to some of the cellular communication protocols discussed herein. The UE 106 may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS) (e.g., GPS or GLONASS), one orAtty Dkt. P68852WO1 (1784-0070WO1) more mobile television broadcasting standards (e.g., ATSC-M / H), and / or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0065] In one or more embodiments, the UE 106 may be a device with cellular communication capability such as a mobile phone, a hand-held device, a computer, a laptop, a tablet, a smart watch, or other wearable device, or virtually any type of wireless device.

[0066] The UE 106 may include a processor (processing element) that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method aspects described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 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 that are configured to perform (e.g., individually or in combination) any of the method aspects described herein, or any portion of any of the method aspects described herein.

[0067] The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some aspects, the UE 106 may be configured to communicate using, for example, NR or LTE using at least some shared radio components. As additional possibilities, the UE 106 could be configured to communicate using CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE using a single shared radio and / or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for a multiple-input multiple output (MIMO) configuration) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, and the like), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 may share one or more parts of a receive and / or transmit chain between multiple wireless communication technologies, such as those discussed above.

[0068] In some aspects, the UE 106 may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 106 may include one or more radios which are shared between multiple wireless communication protocols,Atty Dkt. P68852WO1 (1784-0070WO1) and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 106 might include a shared radio for communicating using either of LTE or 5G NR (or either of LTE or 1xRTT, or either of LTE or GSM, among various possibilities), and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0069] In some aspects, a downlink resource grid may be used for downlink transmissions from any of the base stations 102 to the UEs 106, while uplink transmissions may utilize similar techniques. The grid may be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for Orthogonal Frequency Division Multiplexing (OFDM) systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid may comprise a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a set of resource elements. There are several different physical downlink channels that are conveyed using such resource blocks.

[0070] One such channel is the physical downlink shared channel (PDSCH) that may carry user data and higher layer signaling to the UEs 106. The PDCCH may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 106 about the transport format, resource allocation, and HARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 102 within a cell) may be performed at any of the base stations 102 based on channel quality information fed back from any of the UEs 106. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs.

[0071] The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource elementAtty Dkt. P68852WO1 (1784-0070WO1) groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH may be transmitted using one or more CCEs, depending on the size of the Downlink Control Information (DCI) and the channel condition. There may be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).

[0072] Example Communication Device

[0073] Figure 2 illustrates user equipment 106 (e.g., one of the devices 106A through 106N) in communication with a base station 102 or other user equipment 106, according to some aspects. The UE 106 may be a device with cellular communication capability such as a mobile phone, a hand-held device, a computer, a laptop, a tablet, a smart watch, or other wearable device, or virtually any type of wireless device.

[0074] The UE 106 may include a processor (processing element) that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method aspects described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 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 that are configured to perform (e.g., individually or in combination) any of the method aspects described herein, or any portion of any of the method aspects described herein.

[0075] The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some aspects, the UE 106 may be configured to communicate using, for example, NR or LTE using at least some shared radio components. As additional possibilities, the UE 106 could be configured to communicate using CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE using a single shared radio and / or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 may share one or more parts of a receive and / or transmit chain between multiple wireless communication technologies, such as those discussed above.Atty Dkt. P68852WO1 (1784-0070WO1)

[0076] In some aspects, the UE 106 may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 106 may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 106 might include a shared radio for communicating using either of LTE or 5G NR (or either of LTE or 1xRTT, or either of LTE or GSM, among various possibilities), and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0077] In some aspects, a downlink resource grid can be used for downlink transmissions from any of the base stations 102 to the UEs 106, while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid may comprise a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements. There are several different physical downlink channels that are conveyed using such resource blocks.

[0078] The PDSCH may carry user data and higher layer signaling to the UEs 106. The PDCCH may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 106 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 102 within a cell) may be performed at any of the base stations 102 based on channel quality information fed back from any of the UEs 106. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs.

[0079] The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaverAtty Dkt. P68852WO1 (1784-0070WO1) for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).

[0080] Figure 2 illustrates an example simplified block diagram of a communication device 106, according to some aspects. It is noted that the block diagram of the communication device of Figure 2 is only one example of a possible communication device. According to aspects, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, and / or a combination of devices, among other devices. As shown, the communication device 106 may include a set of components 200 configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components 200 may be implemented as separate components or groups of components for the various purposes. The set of components 200 may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device 106.

[0081] For example, the communication device 106 may include various types of memory (e.g., including NAND flash 210), an input / output interface such as connector I / F 220 (e.g., for connecting to a computer system; dock; charging station; input devices, such as a microphone, camera, keyboard; output devices, such as speakers; etc.), the display 260, which may be integrated with or external to the communication device 106, and wireless communication circuitry 230 (e.g., for LTE, LTE-A, NR, UMTS, GSM, CDMA2000, Bluetooth, Wi-Fi, NFC, GPS, etc.). In some aspects, communication device 106 may include wired communication circuitry (not shown), such as a network interface card, e.g., for Ethernet.

[0082] The wireless communication circuitry 230 may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antenna(s) 335 as shown. The wireless communication circuitry 230 may include cellular communication circuitry and / or short to medium range wireless communication circuitry and may include multiple receive chains and / orAtty Dkt. P68852WO1 (1784-0070WO1) multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a multiple-input multiple output (MIMO) configuration.

[0083] In some aspects, as further described below, cellular communication circuitry 230 may include one or more receive chains (including and / or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and / or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR). In addition, in some aspects, cellular communication circuitry 230 may include a single transmit chain that may be switched between radios dedicated to specific RATs. For example, a first radio may be dedicated to a first RAT, e.g., LTE, and may be in communication with a dedicated receive chain and a transmit chain shared with a second radio. The second radio may be dedicated to a second RAT, e.g., 5G NR, and may be in communication with a dedicated receive chain and the shared transmit chain. In some aspects, the second RAT may operate at mmWave frequencies. As mmWave systems operate in higher frequencies than typically found in LTE systems, signals in the mmWave frequency range are heavily attenuated by environmental factors. To help address this attenuating, mmWave systems often utilize beamforming and include more antennas as compared LTE systems. These antennas may be organized into antenna arrays or panels made up of individual antenna elements. These antenna arrays may be coupled to the radio chains.

[0084] The communication device 106 may also include and / or be configured for use with one or more user interface elements. The user interface elements may include any of various elements, such as display 260 (which may be a touchscreen display), a keyboard (which may be a discrete keyboard or may be implemented as part of a touchscreen display), a mouse, a microphone and / or speakers, one or more cameras, one or more buttons, and / or any of various other elements capable of providing information to a user and / or receiving or interpreting user input.

[0085] The communication device 106 may further include one or more smart cards 245 that include SIM (Subscriber Identity Module) functionality, such as one or more UICC(s) (Universal Integrated Circuit Card(s)) cards 245.

[0086] As shown, the SOC 200 may include processor(s) 202, which may execute program instructions for the communication device 106 and display circuitry 204, which may perform graphics processing and provide display signals to the display 260. The processor(s) 202 may also be coupled to memory management unit (MMU) 240, which may be configured to receive addresses from the processor(s) 202 and translate those addresses to locations in memory (e.g.,Atty Dkt. P68852WO1 (1784-0070WO1) memory 206, read only memory (ROM) 250, NAND flash memory 210) and / or to other circuits or devices, such as the display circuitry 204, wireless communication circuitry 230, connector I / F 220, and / or display 260. The MMU 240 may be configured to perform memory protection and page table translation or set up. In some aspects, the MMU 240 may be included as a portion of the processor(s) 202.

[0087] As noted above, the communication device 106 may be configured to communicate using wireless and / or wired communication circuitry. As described herein, the communication device 106 may include hardware and software components for implementing any of the various features and techniques described herein. The processor 202 of the communication device 106 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 202 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 202 of the communication device 106, in conjunction with one or more of the other components 200, 204, 206, 210, 220, 230, 240, 245, 250, 260 may be configured to implement part or all of the features described herein.

[0088] In addition, as described herein, processor 202 may include one or more processing elements. Thus, processor 202 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor 202. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 202.

[0089] Further, as described herein, wireless communication circuitry 230 may include one or more processing elements. In other words, one or more processing elements may be included in wireless communication circuitry 230. Thus, wireless communication circuitry 230 may include one or more integrated circuits (ICs) that are configured to perform the functions of wireless communication circuitry 230. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of wireless communication circuitry 230.

[0090] Example Base Station

[0091] Figure 3 illustrates an example block diagram of a base station 102, according to someAtty Dkt. P68852WO1 (1784-0070WO1) aspects. It is noted that the base station of Figure 3 is merely one example of a possible base station. As shown, the base station 102 may include processor(s) 304 which may execute program instructions for the base station 102. The processor(s) 304 may also be coupled to memory management unit (MMU) 340, which may be configured to receive addresses from the processor(s) 304 and translate those addresses to locations in memory (e.g., memory 360 and read only memory (ROM) 350) or to other circuits or devices.

[0092] The base station 102 may include at least one network port 370. The network port 370 may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices 106, access to the telephone network as described above in Figures 1 and 2.

[0093] The network port 370 (or an additional network port) may also or alternatively be configured to couple to a cellular network, e.g., 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 UE devices 106. In some cases, the network port 370 may couple to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider).

[0094] In some aspects, base station 102 may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or “gNB.” In such aspects, base station 102 may be connected to a legacy evolved packet core (EPC) network and / or to a NR core (NRC) / 5G core (5GC) network. In addition, base station 102 may be considered a 5G NR cell and may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs.

[0095] The base station 102 may include at least one antenna 334, and possibly multiple antennas. The at least one antenna 334 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE devices 106 via radio 330. The antenna 334 communicates with the radio 330 via communication chain 332. Communication chain 332 may be a receive chain, a transmit chain or both. The radio 330 may be configured to communicate via various wireless communication standards, including, but not limited to, 5G NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0096] The base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some instances, the base station 102 may include multiple radios, which may enable the base station 102 to communicate according to multiple wirelessAtty Dkt. P68852WO1 (1784-0070WO1) communication technologies. For example, as one possibility, the base station 102 may include an LTE radio for performing communication according to LTE as well as a 5G NR radio for performing communication according to 5G NR. In such a case, the base station 102 may be capable of operating as both an LTE base station and a 5G NR base station. When the base station 102 supports mmWave, the 5G NR radio may be coupled to one or more mmWave antenna arrays or panels. As another possibility, the base station 102 may include a multi-mode radio, which is capable of performing communications according to any of multiple wireless communication technologies (e.g., 5G NR and LTE, 5G NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0097] As described further subsequently herein, the BS 102 may include hardware and software components for implementing or supporting implementation of features described herein. The processor 304 of the base station 102 may be configured to implement or support implementation of part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer readable memory medium). Alternatively, the processor 304 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) the processor 304 of the BS 102, in conjunction with one or more of the other components 330, 332, 334, 340, 350, 360, 370 may be configured to implement or support implementation of part or all of the features described herein.

[0098] In addition, as described herein, processor(s) 304 may include one or more processing elements. Thus, processor(s) 304 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor(s) 304. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 304.

[0099] Further, as described herein, radio 330 may include one or more processing elements. Thus, radio 330 may include one or more integrated circuits (ICs) that are configured to perform the functions of radio 330. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of radio 330.

[0100] Phase Offset Reporting for mTRP Operation

[0101] Figure 4A illustrates a system according to some aspects disclosed herein. In theAtty Dkt. P68852WO1 (1784-0070WO1) system 400 of Figure 4, four TRPs 402-1, 402-2, 402-3, and 402-4 with indexes TRP0, TRP1, TRP2, and TRP3, respectively, are presented in communication with the UE 406. Embodiments are not limited to the use of four TRPs, but may employ any number of TRPs greater than or equal to two. Each TRP 402-1, 402-2, 402-3, and 402-4 may transmit a signal 403-1, 403-2, 403-3, and 403-4 to the UE 406. The UE 206 measures each of the received signals 403-1, 403-2, 403-3, and 403-4 to determine time, frequency and / or phase offsets between the signals 403-1, 403-2, 403- 3, and 403-4. Herein, the different types of offsets that may be measured are collectively referred to as phase offsets.

[0102] The communication may occur using different subbands that must be considered when measuring phase offsets. Figure 4B illustrates a frequency range in accordance with some aspects. In Figure 4B, a number of subbands NSBthat cover a frequency range are indexed as Subband0, Subband1, …, Subband(NSB-1).

[0103] To facilitate mTRP operation, particularly mTRP CJT operation, a UE may measure and report the phase offsets ^^^^^,^, for different TRPs at different frequency domain subbands,where ^^ = 0,1, ... ,^^்ோ^ − 1 represents the TRP index, with ^^்ோ^ being the total number of TRPsand s= 0,1, ... ,^^ௌ^ − 1 is the frequency domain subband index with ^^ௌ^ being the total numberof subbands.

[0104] Figure 5 illustrates a method in accordance with some aspects. The general process 500 includes the UE receiving a signal, e.g., a CSI-RS, from a first TRP and performing measurements on the CSI-RS in Step 510. For example, in the context of Figure 4A, the UE 406 receives a CSI-RS in the signal 403-1 from TRP 0402-1. The measurements include measuring a first phase associated with the CSI-RS. In Step 520, a second CSI-RS is received from a second TRP, and measurements, including a second phase, are performed. For example, in the context of Figure 4A, the UE 406 receives a second CSI-RS in the signal 403-2 from TRP 1402-2.

[0105] In Step 530, a CSI report is transmitted to the network (via a TRP) that includes a first phase offset determined based on the first phase and the second phase received from the first TRP and the second TRP, respectively. The CSI report also includes other relevant information in view of the determination as described herein, such as the identities of the TRPs and frequency bands involved in the measurement. For example, the CSI report may at least include the identity of the second TRP and a subband associated with each reported phase offset.

[0106] In some embodiments, a TRP may be selected as a reference TRP to be used forAtty Dkt. P68852WO1 (1784-0070WO1) reporting the measurements of the offsets. In such embodiments, for the different frequency domain subbands (indexed by s), the reference TRP is represented by the TRP with index ^^^^^. As such, the reported phase offset ^^^^^,^, for TRP ^^ is the difference between the phasemeasurement of TRP ^^ and the phase measurement of the reference TRP ^^^^^, i.e., ^^^^^,^ = ^̃^^,^ −^̃^^^^^,^, wherein ^̃^^,^ and ^̃^^^^^,^ are the measured phases from TRP ^^ and reference TRP ^^^^^, insubband ^^, respectively.

[0107] In terms of the choice of the reference TRP, embodiments may select the reference TRP to be the first TRP. For example, the reference TRP may be the TRP that corresponds to the CSI-RS resource that has the smallest identification, e.g., the TRP with the smallest nzp-CSI-RS- ResourceId. As another example, the reference TRP may be the TRP that corresponds to the CSI- RS resource that is configured first in the list of CSI-RS resources in the CSI-RS resource set configured as the CMR for the phase offset measurement. In embodiments, the TRP that is used as the reference TRP may be indicated in the CSI report transmitted to the network.

[0108] In embodiments, the frequency domain subbands may or may not be correlated to the reference TRP. That is, the same reference TRP may be used for different frequency domain subbands, or a different reference TRP may be used for each of the different frequency subbands.

[0109] In embodiments, the UE may report that one or more TRPs and / or one or more frequency domain subbands are invalid. For example, an invalid codepoint may be introduced in the quantization / reporting of the phase offsets. The invalidity may be established at the TRP level, the subband level, or combinations thereof. For example, at the TRP level, all the subbands in a TRP are either valid or invalid, and at the subband level, different subbands in a TRP may be either valid or invalid.

[0110] In some embodiments, the UE may first report the indexes of the invalid TRP and / or frequency domain subbands, and then report the quantized phase offsets ^^^^^,^of the valid TRPs and / or frequency domain subbands. The determination that a TRP / subband is invalid may be subject to a specific UE implementation.

[0111] In embodiments, the frequency domain subband is established in terms of a number^^^^௭^ௌ^ of Physical Resource Blocks (PRBs) in the subband. The subbands are distributed across anactive DL Bandwidth Part (BWP) that is also established in terms of a number ^^^^^^௭^^ of PRBs. The size ^^ௌ^^^௭^of the frequency domain subband may be a function of the size ^^^^^^௭^^ of the activeAtty Dkt. P68852WO1 (1784-0070WO1)DL BWP. For example, a larger size ^^^^௭^^^^ active DL BWP may be associated with a larger size^^^^௭^ௌ^ frequency domain subband.

[0112] Figures 6A and 6B illustrate different options for distributing frequency domain subbands across an active DL BWP according to some aspects. In embodiments of Figure 6A, the start of the first subband, Subband 0, is at the start of the Active DL BWP. The first subband, Subband 0, is followed by a number of equally-sized ^^ௌ^^^௭^subbands, e.g., Subband 1. However, the size ^^^^^^௭^^ of the DL BWP may not be an integer multiple of the size ^^ௌ^^^௭^of the subband. Insuch conditions, the size of the last subband, Subband NSB-1, may be adjusted based on the size^^^^௭^^^^ of the DL BWP. For example, the size of the last subband, Subband NSB-1, may be theremainder of PRBs after dividing the DL BWP into the equally-sized ^^ௌ^^^௭^subbands. In otherwords, if ^^^^^^௭^^^^^^^^^^ௌ^^^௭^≠ 0, the size of the last subband is ^^^^^^௭^^^^^^^^^^ௌ^^^௭^, and if^^^^௭^^^^^^^^^^^௭^ = 0, the size of the last subband is ^^^^௭^^^^ ௌ^ ௌ^ . Embodiments of Figure 6A may beemployed when the size ^^ௌ^^^௭^of the frequency domain subband is established to distribute the subbands across the DL BWP.

[0113] In the embodiments of Figure 6B, the start of the first subband is determined from a Common Resource Block (CRB) 0 or the Point A, for example as described in TS 38.211. In these embodiments, the start of the active DL BWP is ^^^^^௧^^^௧PRBs from CRB 0 or Point A. The totalbandwidth (^^^௧^^௧^^^ + ^^^^௭^^^^ ) may still be divided into equally-sized frequency domain subbands^^^^௭^ோ^ in a manner similar to that shown in Figure 6A; however, the first subband, Subband 0, andthe last subband, Subband NSB-1, may contain fewer PRBs, i.e., less than ^^ோ^^^௭^. In other words,the first subband, Subband 0, may contain ^^^^௭^ ^௧^^௧ ^^௭^ோ^ − (^^^^^ ^^^^^^^^ோ^ ) PRBs.

[0114] Similar to Figure 6A, the size of the last subband, Subband NSB-1, may be theremainder of PRBs after dividing the total bandwidth (^^^௧^^௧ ^^^^ + ^^ ^௭^^^^ ) into the equally-sized^^^^௭^ subbands. In other words, if (^^^௧^^௧^^^ + ^^^^௭^^^^ )≠ 0, the size of the lastis (^^^௧^^௧ + ^^^^௭^ )^^^^^^^^^^௭^, and if (^^^௧^^௧ + ^^^^௭^ )^ ^^௭^^^^ ^^^ ோ^ ^^^ ^^^ ^^^^^^^ோ^ = 0, the size of the last

[0115] In embodiments, the network may configure a subset of the different subbands for the UE to measure and report. The UE receives from the network an indication of which frequency domain subbands to include in the phase measurement and reporting. For example, the subset configuration may use a NSB-bit bitmap to indicate the frequency domain subbands, where “1”Atty Dkt. P68852WO1 (1784-0070WO1) represents a corresponding subband to have phase offsets reported, and “0” represents a corresponding subband will not have phase offsets reported.

[0116] Considering up to four TRPs, each with a number of subbands, the amount of processing for the offset determinations, as well as the amount of data to be transmitted in a CSI report, the burden on the UE could cause unwanted latency and other issues in a CJT process. Accordingly, in some embodiments, the CSI overhead and UE processing complexity is reduced. For example, a limitation on the maximum number of frequency domain subbands may be imposed. This may be established through the UE capability. For example, the UE may report a maximum number of frequency domain subbands in a UE capability message via RRC signaling.

[0117] The UE quantizes and encodes the phase information for different frequency domain subbands, ^^^,^, when measuring and reporting phases from different TRPs in accordance with embodiments. In some embodiments, each frequency domain subband ^^^,^for the different subbands may be encoded independently and transmitted.

[0118] In other embodiments, each frequency domain subband ^^^,^may be encoded differentially using a reference subband. For example, the first subband, subband s=0, is established as the reference subband. Accordingly, phase offsets for subband s=0 need not be included in the reporting. For the other subbands, s≠0, the reported phase offset is the quantizedversion of the phase minus the reference phase (^^^,^ − ^^^,^). The subband index of the referencesubband may be included in the reporting.

[0119] In some embodiments, a linear approximation may be used to reduce the reporting overhead. For example, the phase may be approximated as a reference phase plus the subbandindex times an offset, i.e., ^^^,^ = ^^^,^ + ^^^^ఏ. In such embodiments, the offset ^^ఏ is quantizedand reported in the CSI report. The reference phase ^^^,^may or may not necessarily be included in the CSI report.

[0120] In order to encode the relevant information, such as the phase ^^^,^, differential offset^^^,^ − ^^^,^, and / or linear offset ^^ఏ, described above, embodiments may employ a uniform equaldistance quantization. For example, the general formulation for the quantization is ^^ ⋅ ଶగெ, whereଶగெ is the step size of the uniform quantization, and ^^ is the reported quantized phase offset. Thevalue of M, which determines the step size, may be hard coded or configured by the network. Different options may be selected for the range of D. In one option, the value of D may be in theAtty Dkt. P68852WO1 (1784-0070WO1)range of zero to a maximum D, ^^ = {0,1... ,^^^^௫}. Alternatively, the value of D may be in therange of negative maximum D to positive maximum D, ^^ = {−^^^^௫, ... ,−1,0,1... ,^^^^௫}.

[0121] For example, if the phase is encoded differentially with respect to a reference, ^^^,^ −^^^,^, and the lowest phase is selected to be the reference phase, then the first option may be usedto quantize the phase offset (because the measured D will always be greater than or equal to 0).However, given the restriction on the choice of reference, it may be desirable to employ the range^^ = {−^^^^௫, ... ,−1,0,1... ,^^^^௫}.

[0122] In these embodiments, M is related to the step size for the quantization, but only asmall range may be desired for reporting. Therefore, in embodiments, ^^^^௫ < ^^ or ^^^^௫ = ^^.

[0123] As described above in Figure 5, the UE receives a signal from a TRP and performs measurements on the signal. In some embodiments, a TRS may be used as the CMR for the measurement. For example, the TRS is established in the NZP-CSI-RS-ResourceSet with higher layer parameter trs-Info configured in current standards. Also, each TRP is configured with its own associated TRS. Accordingly, a TRS signal may be used to determine the different offsets reported.

[0124] When a TRS is used to determine the offsets, for periodic TRS transmission, more than one TRS resource set may be configured as the CMR for the CSI report. For example, up to four TRS resource sets may be configured as the CMR, with each TRS resource set mapped to a different TRP.

[0125] For an aperiodic TRS, the TRS is established in CSI-AssociatedReportConfigInfo, in accordance with current standards. Also, more than one nzp-CSI-RS may be configured. Accordingly, multiple resource sets may be configured, with each resource set mapping to a different TRP. The quasi co-location information qcl-info may also be configured, such that each qcl-info may be used to configure the Transmission Configuration Indicator (TCI) state of the TRS mapping to the different TRPs.

[0126] In accordance with embodiments, when 1-port CSI-RS is used as the CMR, the CSI-RS frequency domain density ^^ may be restricted. For example, only the highest density (^^ = 3)may be allowed, or only the lowest density (^^ = 0.5) may be allowed. In embodiments, the twohighest densities (^^ = 1,3) may be allowed, or the two lowest densities (^^ = 0.5,1) are allowed.In these embodiments, the UE may report the CSI-RS frequency domain density that UE supports for phase offset reporting to the network.Atty Dkt. P68852WO1 (1784-0070WO1)

[0127] Embodiments disclosed herein provide detailed designs for phase offset measurement and reporting. Embodiments help establish the CMR configurations for measuring the phase offsets, as well as CSI report for encoding and transmitting the phase information. Embodiments may be instrumental in performing CJT from multiple TRPs. Communication using mTRP CJT may achieve better performance when the coherency can be maintained between the antenna elements from the different TRPs.

[0128] Aspects of the present disclosure may be realized in any of various forms. For example, some aspects may be realized as a computer-implemented method, a computer-readable memory medium, or a computer system. Other aspects may be realized using one or more custom-designed hardware devices such as ASICs. Still other aspects may be realized using one or more programmable hardware elements such as FPGAs.

[0129] In some aspects, a non-transitory computer-readable memory medium may be configured so that it stores program instructions and / or data, where the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of a method aspects described herein, or, any combination of the method aspects described herein, or, any subset of any of the method aspects described herein, or, any combination of such subsets.

[0130] In some aspects, a device (e.g., a UE 106, a BS 102) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method aspects described herein (or, any combination of the method aspects described herein, or, any subset of any of the method aspects described herein, or, any combination of such subsets). The device may be realized in any of various forms.

[0131] Although the aspects above 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 embrace all such variations and modifications.

Claims

Atty Dkt. P68852WO1 (1784-0070WO1) CLAIMS What is claimed is:

1. A method performed by a User Equipment (UE), the method comprising: receiving a first Channel State Information-Reference Signal (CSI-RS) from a first Transmission Reception Point (TRP); measuring a first phase associated with the first CSI-RS; receiving a second CSI-RS from a second TRP; measuring a second phase associated with the second CSI-RS; and transmitting a CSI report to the first TRP or the second TRP, the CSI report comprising: a first phase offset based on the first phase and the second phase, an indication identifying the second TRP, and an indication of a frequency domain subband for the first phase offset.

2. The method of claim 1, wherein the first CSI-RS and the second CSI-RS are within a first frequency domain subband.

3. The method of claim 1, wherein the first TRP is a reference TRP, and the first phase offset is the difference of the second phase minus the first phase from the reference TRP.

4. The method of claim 3, further comprising: determining the first TRP is the reference TRP based on a resource identification number of a first CSI-RS resource from the first TRP.

5. The method of claim 3, further comprising: determining the first TRP is the reference TRP because a first CSI-RS resource from the first TRP is the first CSI-RS resource listed on a list of CSI-RS resources configured as a Channel Measurement Resource (CMR).

6. The method of claim 3, wherein the CSI report further comprises an indication that the first TRP is the reference TRP.Atty Dkt. P68852WO1 (1784-0070WO1) 7. The method of claim 3, wherein the first TRP is the reference TRP for two or more frequency domain subbands.

8. The method of claim 1, wherein the CSI report further comprises: an indication that one or more frequency domain subbands are invalid.

9. The method of claim 1, wherein the CSI report further comprises: an indication that one or more TRPs are invalid.

10. The method of claim 1, wherein the frequency domain subband is one of a plurality of equally-sized frequency domain subbands distributed across an active downlink (DL) bandwidth part (BWP), and wherein the size of the frequency domain subband is a determined number of physical resource blocks (PRBs).

11. The method of claim 10, wherein the plurality of frequency domain subbands further comprises a single frequency domain subband with less PRBs than the remaining equally- sized frequency domain subbands.

12. The method of claim 10, wherein the start of the plurality of frequency domain subbands is determined from a common resource block (CRB).

13. The method of claim 1, further comprising: receiving an indication of a subset of a plurality of frequency domain subbands, wherein the CSI report further comprises phase information for each of the frequency domain subbands in the subset.

14. The method of claim 13, wherein the indication is bitmap representing the plurality of frequency domain subbands.

15. The method of claim 1, further comprising: transmitting, to the first TRP or the second TRP, a UE capability message comprising a maximum number of frequency domain subbands for reporting phase information.Atty Dkt. P68852WO1 (1784-0070WO1) 16. The method of claim 1, wherein the first CSI-RS is within a first frequency domain subband and the second CSI-RS is within a second frequency domain subband.

17. The method of claim 1, wherein an indication of a phase offset associated with the first CSI- RS is not included in the CSI report.

18. The method of claim 1, wherein the first phase offset for the second CSI-RS is quantized based on a linear approximation and an index of the frequency domain subband.

19. The method of claim 1, wherein the first phase offset for the second CSI-RS is quantized based on a spatially uniform equal distance approximation.

20. The method of claim 1, further comprising: receiving a third CSI-RS from a third TRP; and measuring a third phase associated with the third CSI-RS, wherein the CSI report further comprises: a second phase offset based on the first phase and the third phase, an indication identifying the third TRP, and an indication of the frequency domain subband for the second phase offset.

21. The method of claim 20, further comprising: receiving a fourth CSI-RS from a fourth TRP; and measuring a fourth phase associated with the fourth CSI-RS, wherein the CSI report further comprises: a third phase offset based on the first phase and the fourth phase, an indication identifying the fourth TRP, and an indication of the frequency domain subband for the third phase offset.

22. A method performed by a User Equipment (UE), the method comprising: receiving a first Tracking Reference Signal (TRS) from a first TRP; measuring a first phase associated with the first TRS; receiving a second TRS from a second TRP;Atty Dkt. P68852WO1 (1784-0070WO1) measuring a second phase associated with the second TRS; transmitting a CSI report to the first TRP or the second TRP, the CSI report comprising: a phase offset based on the first phase and the second phase, an indication identifying the second TRP, and an indication of a frequency domain subband for the phase offset.

23. The method of claim 22, further comprising: receiving, from the first TRP, an indication of a CSI-RS resource set including the first TRS.

24. The method of claim 22, wherein each TRP transmits an associated TRS.

25. The method of claim 22, wherein the first TRS is transmitted periodically.

26. The method of claim 22, further comprising: receiving, from the first TRP, a message comprising an indication of a CSI-RS resource set for the first TRP, wherein the first TRS is one of a plurality of resources included in the CSI-RS resource set.

27. The method of claim 26, wherein the message further comprises quasi co-location information for a Transmission Configuration Indicator (TCI) state for the second TRP.

28. The method of claim 22, further comprising: transmitting, to the first TRP or the second TRP, a UE capability message comprising a minimum or a maximum frequency domain density for reporting phase information.

29. A UE configured to perform the methods of any of claims 1–28.

30. A non-transitory computer readable medium configured to store and execute instructions to perform the methods of any of claims 1–28.Atty Dkt. P68852WO1 (1784-0070WO1) 31. A baseband processor configured to execute instructions to cause a UE to perform the methods of any of claims 1–28.

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