Uplink (UL) transmit timing control for UL-only network nodes

Abstract

A method performed by a user equipment for sending an uplink (UL) communication is provided. The method comprises sending a UL communication for reception at a first network (NW) node. The sending of the UL communication including applying a first timing offset to a UL timing for communication of the UL communication. The first timing offset accounting for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to a second NW node used to determine the UL timing.

Description

UPLINK (UL) TRANSMIT TIMING CONTROL FOR UL-ONLY NETWORK NODESCROSS REFERENCE TO RELATED APPLICATION

[0001] This patent application claims the benefit of and priority to U.S. Provisional App. No. 63 / 555,285 filed February 19, 2024, titled “UPLINK (UL) TRANSMIT TIMING CONTROL FOR UL-ONLY NETWORK NODES.”FIELD

[0002] This present disclosure relates generally to telecommunication systems and methods, and in particular to controlling timing of UL transmissions from user equipment (UE) such that the UL transmissions reach a base station within a corresponding reception window in the base station.BACKGROUND

[0003] Unless otherwise indicated in the present disclosure, the materials described in the present disclosure are not prior art to the claims in the present application and are not admitted to be prior art by inclusion in this section.

[0004] Challenges currently exist with respect to UL only transmission reception points (TRPs). For example, a UL-only TRP does not transmit a downlink (DL) reference signal (RS), such as synchronization signal blocks (SSB) to the UE. Instead, the UL only TRP may only receive UL traffic from the UE. Accordingly, UL transmissions from the UE may be received by the UL only TRP outside a corresponding reception window.

[0005] The subject matter claimed in the present disclosure is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described in the present disclosure may be practiced.SUMMARY

[0006] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0007] Various computer-implemented systems, methods, and articles of manufacture for controlling timing of UL transmissions from the UE such that the UL transmissions reach a base station within a corresponding reception window in the base station are disclosed herein. For example, according to one or more embodiments of the present disclosure, to help the UL transmissions from the UE reach the base station within the corresponding reception window,a UL timing control procedure may be implemented. The UL timing procedure may include indicating a DL timing offset to the UE to adjust DL reference timing obtained from the DL RS of an anchor TRP.

[0008] In one embodiment, a method performed by a UE for sending a UL communication is disclosed. The method comprises sending a UL communication for reception at a first network (NW) node. The sending of the UL communication including applying a first timing offset to a UL timing for communication of the UL communication. The first timing offset accounting for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to a second NW node used to determine the UL timing.

[0009] In one embodiment, a user equipment comprises processing circuitry configured to perform the method above.

[0010] In one embodiment, a method performed by a network node for receiving a UL communication is disclosed. The method comprises receiving, at a first NW node, a UL communication. A timing of receiving the UL communication being based on application of a first timing offset to a UL timing for communication of the UL communication. The first timing offset accounting for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to second NW node used to determine the UL timing.

[0011] In one embodiment, a network node comprises processing circuitry configured to perform the method above.

[0012] The object and advantages of the embodiments will be realized and achieved at least by the elements, features, and combinations particularly pointed out in the claims. Both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a better understanding of the various described embodiments, reference should be made to the Detailed Description below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

[0014] FIG. 1 illustrates an example of a communication system in accordance with some embodiments.

[0015] FIG. 2 illustrates an exemplary user equipment in accordance with some embodiments.

[0016] FIG. 3 illustrates an exemplary network node in accordance with some embodiments.

[0017] FIG. 4 is a block diagram illustrating an exemplary virtualization environment in which functions implemented by some embodiments may be virtualized.

[0018] FIG. 5 is a block diagram illustrating an example slot that includes 14 symbols.

[0019] FIG. 6 is a block diagram illustrating an example UL slot structure.

[0020] FIGs. 7 A and 7B are sequence diagrams illustrating example sequences of slot timing.

[0021] FIG. 8 is a block diagram illustrating a serving cell that includes an anchor TRP and a UL only TRP that are not co-located.

[0022] FIG. 9 is a block diagram illustrating various synchronization scenarios of slots corresponding to an anchor TRP and a UL only TRP.

[0023] FIG. 10 is a block diagram illustrating various scenarios of UL transmissions using DL reference timing of the anchor TRP.

[0024] FIG. 11 is a block diagram illustrating a scenario of UL transmissions using the DL reference timing of an anchor TRP and an offset delay.

[0025] FIGs. 12 and 13 are flowcharts illustrating embodiments of method operations.DETAILED DESCRIPTION

[0026] Certain aspects of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. This concept may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the concept to those skilled in the art.

[0027] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise:

[0028] The phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment, though it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope of the invention.

[0029] As used herein, the term “or” is an inclusive “or” operator and is equivalent to the term “and / or,” unless the context clearly dictates otherwise.

[0030] The term “based on” is not exclusive and allows for being based on additional factors not described unless the context clearly dictates otherwise.

[0031] As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously. Within the context of a networked environment where two or more components or devices are able to exchange data, the terms “coupled to” and “coupled with” are also used to mean “communicatively coupled with”, possibly via one or more intermediary devices.

[0032] In addition, throughout the specification, the meaning of “a”, “an”, and “the” includes plural references, and the meaning of “in” includes “in” and “on”.

[0033] Although some of the various embodiments presented herein constitute a single combination of inventive elements, it should be appreciated that the inventive subject matter is considered to include all possible combinations of the disclosed elements. As such, if one embodiment comprises elements A, B, and C, and another embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly discussed herein. Further, the transitional term “comprising” means to have as parts or members, or to be those parts or members. As used herein, the transitional term “comprising” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

[0034] In various embodiments, the devices, instruments, systems, and methods described herein may be used to facilitate proper timing configuration of beamforming by a repeater node.

[0035] It is noted that description herein is not intended as an extensive overview, and as such, concepts may be simplified in the interests of clarity and brevity. Any process or method or corresponding steps of any process or method described in this application may be performed in any order and may omit any of the steps in the process. Processes or methods may also be combined with other processes or steps of other processes, in part or in whole. Parts of processes or methods, or corresponding steps may be combined with other parts of processes or methods, or corresponding steps.

[0036] Figure 1 shows an example of a communication system 100 in accordance with some embodiments.

[0037] In the example, the communication system 100 includes a telecommunication network 102 that includes an access network 104, such as a radio access network (RAN), and a core network 106, which includes one or more core network nodes 108. The access network 104 includes one or more access network nodes, such as network nodes 110A and HOB (oneor more of which may be generally referred to as network nodes 110), or any other similar 3rdGeneration Partnership Project (3 GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 102 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 102, including one or more network nodes 110 and / or core network nodes 108.

[0038] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O- CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 110 facilitate direct or indirect connection of UE, such as by connecting UEs 112 A, 112B, 112C, and 112D (one or more of which may be generally referred to as UEs 112) to the core network 106 over one or more wireless connections.

[0039] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 100 may include any number of wired or wireless networks, network nodes, UEs, and / orany other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0040] The UEs 112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 110 and other communication devices. Similarly, the network nodes 110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 112 and / or with other network nodes or equipment in the telecommunication network 102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 102.

[0041] In the depicted example, the core network 106 connects the network nodes 110 to one or more host computing systems, such as host 116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 106 includes one or more core network nodes (e.g., core network node 108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0042] The host 116 may be under the ownership or control of a service provider other than an operator or provider of the access network 104 and / or the telecommunication network 102. The host 116 may host a variety of applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0043] As a whole, the communication system 100 of Figure 1 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2ndgeneration (2G), 3rdgeneration (3G), 4thgeneration (4G), 5thgeneration (5G) standards, or any applicable future generation standard (e.g., 6thgeneration (6G)); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0044] In some examples, the telecommunication network 102 is a cellular network that implements 3 GPP standardized features. Accordingly, the telecommunications network 102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 102. For example, the telecommunications network 102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0045] In some examples, the UEs 112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 104. Additionally, a UE may be configured for operating in single- or multi-radio access technology (RAT) or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, New Radio (NR) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0046] In the example, the hub 114 communicates with the access network 104 to facilitate indirect communication between one or more UEs (e.g., UE 112C and / or 112D) and network nodes (e.g., network node HOB). In some examples, the hub 114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 114 may be a broadband router enabling access to the core network 106 for the UEs. As another example, the hub 114 may be a controller that sendscommands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 110, or by executable code, script, process, or other instructions in the hub 114. As another example, the hub 114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 114 may be a content source. For example, for a UE that is a VR device, display, loudspeaker, or other media delivery device, the hub 114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 114 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0047] The hub 114 may have a constant / persistent or intermittent connection to the network node HOB. The hub 114 may also allow for a different communication scheme and / or schedule between the hub 114 and UEs (e.g., UE 112C and / or 112D), and between the hub 114 and the core network 106. In other examples, the hub 114 is connected to the core network 106 and / or one or more UEs via a wired connection. Moreover, the hub 114 may be configured to connect to an M2M service provider over the access network 104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 110 while still connected via the hub 114 via a wired or wireless connection. In some embodiments, the hub 114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node HOB. In other embodiments, the hub 114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 110B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0048] Figure 2 shows a UE 200 in accordance with some embodiments. The UE 200 presents additional details of some embodiments of the UE 112 of Figure 1. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage / playback device, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), an Augmented Reality (AR) or Virtual Reality (VR) device, wireless customer-premiseequipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3 GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0049] A UE may support device-to-device (D2D) communication, for example by implementing a 3 GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehi cl e-to- vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0050] The UE 200 includes processing circuitry 202 that is operatively coupled via a bus 204 to an input / output interface 206, a power source 208, a memory 210, a communication interface 212, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 2. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0051] The processing circuitry 202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 210. The processing circuitry 202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 202 may include multiple central processing units (CPUs).

[0052] In the example, the input / output interface 206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or anycombination thereof. An input device may allow a user to capture information into the UE 200. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0053] In some embodiments, the power source 208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 208 may further include power circuitry for delivering power from the power source 208 itself, and / or an external power source, to the various parts of the UE 200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 208 to make the power suitable for the respective components of the UE 200 to which power is supplied.

[0054] The memory 210 may be or be configured to include memory such as randomaccess memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 210 includes one or more application programs 214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 216. The memory 210 may store, for use by the UE 200, any of a variety of various operating systems or combinations of operating systems.

[0055] The memory 210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD- DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMMSDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a universal subscriber identify module (USIM) and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 210 may allow the UE 200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 210, which may be or comprise a device-readable storage medium.

[0056] The processing circuitry 202 may be configured to communicate with an access network or other network using the communication interface 212. The communication interface 212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 222. The communication interface 212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 218 and / or a receiver 220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 218 and receiver 220 may be coupled to one or more antennas (e.g., antenna 222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0057] In the illustrated embodiment, communication functions of the communication interface 212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, transmission control protocol / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0058] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connectionto a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0059] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0060] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 200 shown in Figure 2.

[0061] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, orother equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0062] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0063] Figure 3 shows a network node 300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NRNodeBs (gNBs)), 0-RAN nodes or components of an 0-RAN node (e g., 0-RU, 0-DU, O-CU).

[0064] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an 0-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0065] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi -standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0066] The network node 300 includes a processing circuitry 302, a memory 304, a communication interface 306, and a power source 308. The network node 300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 300 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 304 for different RATs) and some components may be reused (e.g., a same antenna 310 may be shared by different RATs). The network node 300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 300.

[0067] The processing circuitry 302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 300 components, such as the memory 304, to provide network node 300 functionality.

[0068] In some embodiments, the processing circuitry 302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 302 includes one or more of radio frequency (RF) transceiver circuitry 312 and baseband processing circuitry 314. In some embodiments, the RF transceiver circuitry 312 and the baseband processing circuitry 314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 312 and baseband processing circuitry 314 may be on the same chip or set of chips, boards, or units.

[0069] The memory 304 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storagemedia (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computerexecutable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 302. The memory 304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 302 and utilized by the network node 300. The memory 304 may be used to store any calculations made by the processing circuitry 302 and / or any data received via the communication interface 306. In some embodiments, the processing circuitry 302 and memory 304 are integrated.

[0070] The communication interface 306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 306 comprises port(s) / terminal(s) 316 to send and receive data, for example to and from a network over a wired connection. The communication interface 306 also includes radio front-end circuitry 318 that may be coupled to, or in certain embodiments a part of, the antenna 310. Radio front-end circuitry 318 comprises filters 320 and amplifiers 322. The radio front-end circuitry 318 may be connected to an antenna 310 and processing circuitry 302. The radio front-end circuitry may be configured to condition signals communicated between antenna 310 and processing circuitry 302. The radio front-end circuitry 318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 320 and / or amplifiers 322. The radio signal may then be transmitted via the antenna 310. Similarly, when receiving data, the antenna 310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 318. The digital data may be passed to the processing circuitry 302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0071] In certain alternative embodiments, the network node 300 does not include separate radio front-end circuitry 318, instead, the processing circuitry 302 includes radio front-end circuitry and is connected to the antenna 310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 312 is part of the communication interface 306. In still other embodiments, the communication interface 306 includes one or more ports or terminals 316, the radio front-end circuitry 318, and the RF transceiver circuitry 312, as part of a radio unit(not shown), and the communication interface 306 communicates with the baseband processing circuitry 314, which is part of a digital unit (not shown).

[0072] The antenna 310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 310 may be coupled to the radio front-end circuitry 318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 310 is separate from the network node 300 and connectable to the network node 300 through an interface or port.

[0073] The antenna 310, communication interface 306, and / or the processing circuitry 302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 310, the communication interface 306, and / or the processing circuitry 302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0074] The power source 308 provides power to the various components of network node 300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 300 with power for performing the functionality described herein. For example, the network node 300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 308. As a further example, the power source 308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0075] Embodiments of the network node 300 may include additional components beyond those shown in Figure 3 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 300 may include user interface equipment to allow input of information into the network node 300 and to allow output of information from the network node 300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 300. In some embodiments providing a core network node, such as core network node 108 of FIG. 1, somecomponents, such as the radio front-end circuitry 318 and the RF transceiver circuitry 312 may be omitted.

[0076] Figure 4 is a block diagram illustrating a virtualization environment 400 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 400 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 400 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface. Virtualization may facilitate distributed implementations of a network node, UE, core network node, or host.

[0077] Applications 402 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0078] Hardware 404 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 406 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 408a and 408b (one or more of which may be generally referred to as VMs 408), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 406 may present a virtual operating platform that appears like networking hardware to the VMs 408.

[0079] The VMs 408 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 406. Different embodiments of the instance of a virtual appliance 402 may be implemented on oneor more of VMs 408, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0080] In the context of NFV, a VM 408 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 408, and that part of hardware 404 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 408 on top of the hardware 404 and corresponds to the application 402.

[0081] Hardware 404 may be implemented in a standalone network node with generic or specific components. Hardware 404 may implement some functions via virtualization. Alternatively, hardware 404 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 410, which, among others, oversees lifecycle management of applications 402. In some embodiments, hardware 404 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 412 which may alternatively be used for communication between hardware nodes and radio units.New Radio (NR)

[0082] Figure 5 is a block diagram illustrating an example slot 500 that includes 14 symbols. Data scheduling in NR is typically on a time slot basis where the first two symbols contain physical DL control channel (PDCCH) communications and the rest of the symbols contains physical shared data channel communications, either physical DL shared channel (PDSCH) or physical UL shared channel (PUSCH).

[0083] DL transmissions can be dynamically scheduled on a slot-by-slot basis. The scheduling information such as resource allocation and modulation order is included in DL control information (DCI) carried by the PDCCH. DL user data can be carried in PDSCH.

[0084] UL data transmission can also be dynamically scheduled using DCI carried in PDCCH. A UE (such as the UEs 112A-112D of Figure 1 or the UE 200 of Figure 2) may decode UL grants in the DCI and then may transmit data in PUSCH based on the scheduling information in the UL grant.

[0085] In addition to dynamic scheduling of PUSCH, semi-persistent transmission of periodic PUSCH using configured grants (CG) is also supported in NR. In CG type 1, the periodicity as well as a slot offset may be configured by radio resource control (RRC). In CG type 2, the PUSCH transmission can be activated or deactivated dynamically by DCI. For channel estimation purposes, channel state information RSs, channel start information reference signals (CSI-RS), in the DL and sounding RSs (SRS) in the UL may also be supported.

[0086] In UL, physical random-access channel (PRACH), physical UL shared channel (PUSCH), and physical UL control channel (PUCCH) occupy different resource allocations and they do not overlap in the time or frequency domain to avoid inter channel interference among PUCCH / PUSCH / PRACH.

[0087] Figure. 6 is a block diagram illustrating an example UL slot structure 600 (e.g., an example resource allocation). As shown in Figure 6, the example UL slot structure 600 includes four example slots 602, 604, 606, and 608 that are arranged such they do not overlap in time or a frequency domain. The first slot 602 includes a PUCCH / SRS / PUSCH resource allocation. The second slot 604 includes another PUCCH / SRS / PUSCH resource allocation. The third slot 606 includes a random-access channel (RACH) resource allocation. The fourth slot 608 includes yet another PUCCH / SRS / PUSCH resource allocation.

[0088] Different UEs (e.g., UEs 112A-D of Figure 1 or UE 200 of Figure 2) in a cell may typically be located at different positions within the cell and then within different RF propagation delays to the base station (e.g., NR gNB, the network nodes 110A and HOB of Figure 1, or the network node 300 of Figure 3). As the UEs may be at different locations from the gNB, if all UEs transmit to gNB at a same time, transmissions from different UEs may reach the gNB at different times. Unless all UE transmissions are received at the gNB at the same time or within a certain reception window, the UE transmission may interfere with each other and result in demodulation difficulties at the gNB. To help the UL transmissions from a UE reach the base station within the corresponding reception window, a UL timing control procedure may be used.

[0089] Time alignment of the UL transmissions may occur by applying a timing advance at the UE, relative to the received DL timing. The main role of this is to counteract different propagation delays between different UEs

[0090] Figures 7A and 7B are sequence diagrams 702a-b illustrating example sequences of slot timing. As shown in Figures 7A and 7B, the slot diagrams 702a-b include a first slot 704 that indicates when a gNB 701 transmits DL timing. The slot diagrams 702a-b may also include a second slot 706 that indicates when the DL timing is received by a UE 703 (e.g., the UEs 112A-D of Figure 1 or the UE 200 of Figure 2). As shown, the second slot 706 occurs after a first propagation delay (represented in Figures 7A and 7B as TP_1).

[0091] The slot diagrams 702a-b also include a third slot 708 that indicates when the UE 703 transmits the UL timing. As shown in Figure 7A, the third slot 708 may be synchronized with the second slot 706. However, as shown in Figure 7B, the third slot 708 may occur prior to the second slot 706 such that the second slot 706 occurs after a propagation delay of two times TP_1 after the third slot 708.

[0092] The sequence diagrams 702a-b include a fourth slot 710 that indicates when the gNB 701 receives the UL timing. The fourth slot 710 may occur after the third slot 708 such that the fourth slot 710 occurs after a propagation delay equal to or similar to TP_1 after the third slot 708. In addition, the sequence diagrams 702a-b include a fifth slot 712 that indicates when the UE 703 receives the DL slot timing, if the UE 703 is positioned proximate the gNB 701. As shown in Figures 7A and 7B, the fifth slot 712 may occur after a second propagation delay (represented in Figures 7A and 7B as TP_2).

[0093] The sequence diagrams 702a-b include a sixth slot 714 that indicates when the UE 703 transmits the UL slot timing. As shown in Figure 7A, the sixth slot 714 may be transmitted by the UE 703 after the second propagation delay. As shown in Figure 7B, the sixth slot 714 may be transmitted by the UE 703 such that a propagation delay equal to or similar to two times TP_2 occurs between transmission of the sixth slot 714 and reception of the fifth slot 712 by the UE 703. The sequence diagrams include a seventh slot 716 that indicates when the UL timing is received by the gNB 701. As shown, the seventh slot 716 may be received by the gNB 701 after a propagation delay equal to TP_2.

[0094] As shown in Figure 7A, a timing misalignment (represented by arrow 718 in Figure 7A) at the gNB 701 may occur between the fourth slot 710 and the seventh slot 716.

[0095] To achieve the time alignment between different UEs, the base station (e.g. gNB, eNodeB) derives a Timing Advance (TA) value that the UE needs to use for the UL transmissions to reach the base station within the receive window and indicates this to the UE.

[0096] For example, when the UE first accesses a cell (e.g., a gNB), it uses the randomaccess procedure where the UE transmits a PRACH preamble (Msgl for 4-step RACH or MsgA for 2-step RACH) to the base station and the Msgl or Msg A is used by the base station to determine the UE’s initial TA to use for UL transmissions in the cell. As per TS 38.133, the UE performs DL synchronization or acquires DL reference timing within acceptable error limits to perform the random-access procedure. As the random-access procedure is designed to determine the propagation delay (PD) between the gNB and the UE, the gNB may not properly estimate the PD if the UE transmits the RACH communication without proper acquisition of DL frame timing.

[0097] As per technical specification (TS) 38.133, the reference point for the UE initial transmit timing control requirement is the DL timing of the reference cell minus (NTA+NTA offset) *TC, where “NTA” is a measured value sent to the UE as part of TA command, “NTA offset” relates to values that vary depending on certain frequency bands and / or subcarrier spacing, and “Tc” is the basic time unit for the system. The DL timing may be defined as the time when the first path (in time) of the corresponding DL frame used by the UE to determine DL timing is received from the reference cell at the UE antenna. NTA for PRACH is defined as 0. The above said DL frame timing is generally derived from the DL RS (e.g., SSB) for the initial transmissions.

[0098] In existing NR multi-TRP operation, it may be assumed that each node can be used for both DL transmission and UL reception. For NR release 19 (Rel-19), the idea of deploying UL-only nodes in a cell has been proposed in RWS-230248 and RWS-230290. UL-only nodes may be useful in some of the following scenarios:• UL-only nodes deployed at the cell edge to provide better UL coverage for cell edge UEs.• UL-only node deployed in a TDD band where there is dominant UL allocation.• UL-only node deployed in a band that can only be used for UL transmission due to regulatory issues.• UL-only node deployed for network energy saving.

[0099] Figure 8 is a block diagram illustrating a serving cell 800 that includes an anchor TRP 802 and a UL only TRP 804 that are not co-located. The serving cell 800 may also include a gNB 806 and a UE 808.

[0100] The anchor TRP 802 (e.g., anchor node TRP0) provides a full coverage of the serving cell 800 with both DL transmissions and UL transmissions. The UL only TRP 804(e.g., UL only node TRP1) may be deployed at an edge of the cell 800 to improve UL performance of the UE 808 (e.g., a cell edge UE). The anchor TRP 802 and the UL only TRP 804 could be connected, for example to the gNB 806, via a switched front haul (not shown) which when using a Precision Time Protocol (PTP) for synchronization could contribute to various levels of timing misalignment between the anchor TRP 802 and the UL only TRP 804. Such timing misalignment levels may be dependent on characteristics of the deployed network (like number of switches and their characteristics). Note that the embodiments of the present disclosure may be applicable even for the scenario in which the UL-only TRP 804 and the anchor TRP 802 are on different component carriers or carrier frequencies.

[0101] In NR, when the anchor TRP 802 and the UL only TRP 804 are not co-located (e.g., not proximate each other), the anchor TRP 802 and the UL only TRP 804 may not be synchronized, and they may have a synchronization error of up to 3 microseconds (ps) as required for time division duplex (TDD) cell phase synchronization in 3GPP. That means DL or UL slots of the anchor TRP 802 and the UL only TRP 804 may be offset by up to 3ps. This synchronization error is generally not known by different nodes of the cell, and it can be time varying, e.g., as clocks may drift due to changes of synchronization sources or synchronization paths and may introduce different errors at different points in time.

[0102] As shown in Figure 8, the UE 808 is connected to the anchor TRP 802 and the propagation delay between the anchor TRP 802 and the UE 808 is TP_2 and to offload UL traffic, the UE 808 is connected to the UL-only TRP 804 and the propagation delay between the UL-only TRP 804 and the UE 808 is TP L

[0103] The UL only TRP 804 may only receive UL signals and may not transmit any DL signals. For this reason, the UL only TRP 804 can also be referred to as UL-only RP. In the present disclosure, the terms “UL-only node”, “UL-only TRP”, “UL-only RP”, “UL node”, “UL TRP”, and “UL RP” may be used interchangeably.

[0104] It is expected that the demand on capacity and user throughput will increase in the future. It is also expected that UL communications will become a limiting factor, partly due to the natural imbalance of spectral efficiency between UL and DL (which comes from, for instance, different numbers of antennas, different transmit power levels, etc.) but also partly due to an increase of UL-heavy services like gaming. Particularly, sixth generation (6G) is expected to rely a lot on Al which implies a high load on UL. In the present disclosure general reference to “UL” may include any appropriate protocol, transmission, etc. corresponding to UL communications.

[0105] A potential remedy to this is to densify the networks more in the UL than in the DL. This may be done by, for instance, providing radio nodes that only receive in the UL (e.g., the UL only TRP 804) (they do hence not perform any DL transmissions). By using the UL only TRP 804, the UL could be enhanced without enhancing the DL. While there is obviously no direct improvement in DL performance, as compared to normal DL+UL nodes (e.g., the anchor TRP 802), benefits of implementing the UL only TRP 804 include lower complexity, lower weight, lower cost, smaller volumes, lower power consumption, ease of deployment and avoiding the need for permits to deploy radio transmitters. Also, depending on the deployment, the UL only TRP 804 may be deployed at lower heights, compared to DL+UL nodes (e.g., the anchor TRP 802), which improves the UL link to such nodes. A first step to better support the UL only TRP 804 has been included in the NR multiple-input and multiple-output (MIMO) Rel-19 WID (RP-234007), where the power control for frequency range 1 (FR1) and frequency range 2 (FR2) will be enhanced to better support the UL only TRP 804.

[0106] In the Rel-19 MIMO WID (RP-234007), the following objective is included (emphasis added):

[0107] There currently exist certain challenge(s) with respect to implementing the UL onlyTRP 804. For example, the UL only TRP 804 does not transmit any DL RSs, such as SSB, but may only be used to serve UL traffic activities of the UE 808. As a result, the UE 808 may have to rely on other TRPs (such as the Anchor TRP 802) SSB to derive the DL reference timing.

[0108] When slot boundaries of the anchor TRP 802 and the UL only TRP 804 are perfectly aligned in time, the UE 808 may use the DL reference timing of the anchor TRP 802 to perform random access procedure and obtain a TA command to handle the propagation delay between the anchor TRP 802 to the UE 808 and the UL only TRP 804 to the UE 808. In the present disclosure, reference to an “anchor TRP” may include a reception point that performs DL and UL communications and that may be used to help determine transmission timing ofUL signals for reception by the UL only TRP 804. Such a reception point may also be referred to as an anchor network node, an anchor node, a DL / UL TRP, a DL / UL network node, or a DL / UL node.

[0109] However, in practical deployments it may not always be possible to maintain perfect synchronization between different TRPs (e.g., synchronization between the anchor TRP 802 and the UL only TRP 804) especially when they are non-collocated (as shown in Figure 8) and generally a required strict synchronization would add cost and complexity to UL nodes. As such, strict required synchronization may not be preferred. In NR, if the UE 808 transmits RACH after acquiring DL synchronization, the PRACH preamble is expected to be received after the start of the RACH slot at the NW since no compensation for propagation delays is used.

[0110] Figure 9 is a block diagram illustrating various synchronization scenarios 902a-c of slots transmitted by an anchor TRP (e.g., the anchor TRP 802 of Figure 8) and a UL only TRP (e.g., the UL only TRP 804 of Figure 8). As shown in Figure 9, the various scenarios 902a-c include a first sequence of slots 904 (e.g., anchor TRP TRP0 slot timing) that corresponds to the anchor TRP and a second sequence of slots 906 (e.g., UL only TRP slot timing) that corresponds to the UL only TRP.[OHl] In the first scenario 902a, boundaries of the slots (also referred to in the present disclosure as the UL slot boundaries) of the first sequence of slots 904 are synchronized (e.g., aligned) with the boundaries of the slots of the second sequence of slots 906. In the second scenario 902b, the boundaries of the slots of the first sequence of slots 904 are not synchronized with the boundaries of the slots of the second sequence of slots 906 such that the second sequence of slots 906 are ahead (e.g., start before) of the corresponding slots of the first sequence of slots 904. In the third scenario 902c, the boundaries of the slots of the first sequence of slots 904 are not synchronized with the boundaries of the slots of the second sequence of slots 906 such that the first sequence of slots 904 are ahead (e.g., start before) of the corresponding slots of the second sequence of slots 906.

[0112] Figure 10 is a block diagram illustrating various scenarios 1002a-b of UL transmissions using DL reference timing of the anchor TRP.

[0113] With combined reference to Figures 8-10, when the UL slot boundaries of the anchor TRP 802 and the UL only TRP 804 are not synchronized (e.g., the second scenario 902b and the third scenario 902c of Figure 9 and the scenarios 1002a-b of Figure 10), using DL timing of the anchor TRP 802 to transmit RACH preamble to the UL-only TRP 804 may resultin early arrival of the RACH preamble or later arrival of the RACH preamble at the UL-only TRP 804.

[0114] For example, when the UL-only TRP 804 timing is lagging the anchor TRP slot timing (such as the third scenario 902c, and the scenarios 1002a-b of Figure 10) and when the UE 808 acquires DL timing from the anchor TRP 804 as a reference to start transmitting RACH, it may result in early arrival of the RACH preamble at the UL-only TRP 804 (e.g., before the start of RACH occasion or RACH slot at the UL-only TRP 804). This may result in inter-slot interference at the gNB 806 and the gNB 806 may not be able to determine the timing advance correctly. It is noted that the depictions in Figures 9 and 10 relate to scenarios in which the propagation delay from the UE 808 to the anchor TRP 802 is the same as the propagation delay from the UE 808 to the UL-only TRP 804.

[0115] As such, as indicated above, solving this issue may help with the proper working of the UL-only TRP 804 when the anchor TRP 802 and UL only TRP 804 are not synchronized. It is also noted that existing TA protocols are not configured to correct for early random-access arrival since negative values for the TA command are not currently implemented.

[0116] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. For example, according to one or more embodiments of the present disclosure, possible time alignment errors between the UL slot boundaries corresponding to the UL-only TRP 804 and the anchor TRP 802 may be compensated for. For instance, in some embodiments, a DL timing offset may be indicated to the UE 808 that is used to adjust the DL reference timing obtained from the DL RS of the anchor TRP 802. The DL timing offset (also referred to generally as a “timing offset”) may help compensate for the potential alignment errors and may be used by the UE 808 when transmitting UL signals to the UL only TRP 804.

[0117] Certain embodiments may provide one or more of the following technical advantage(s). For example, embodiments of the present disclosure may allow for non-ideal synchronization between the anchor TRP 802 and the UL only TRP 804 that otherwise would add significant cost and complexity to the UL only TRP 804 and its installation. Also, one or more embodiments may avoid new stricter synchronization requirements for existing anchor nodes when adding UL-only nodes. The teachings of certain embodiments may improve UL communications in general (e.g., throughput, bandwidth, etc.) by facilitating the deployment and implementation of the UL only TRP 804.

[0118] As indicated above, according to one or more embodiments of the present disclosure, a method may include applying, at a UE (e.g., the UE 808 of Figure 8), a DL timing offset in the determining of UL transmit timing for UL transmissions intended for reception ata UL-only node (e.g., the UL only TRP 804 of Figure 8). For example, in some embodiments, a method may include determining the UL transmit timing towards the UL-only node using DL reference timing from the anchor node (dl refO) (e.g., the anchor TRP 802 of Figure 8), the dl_timing_offset, NTA, and NTA offset’. In some embodiments, and as discussed in further detail below, NTA offset’ may be the same as legacy NTA offset. For example, in some embodiments, the UL timing may be obtained based on the following expression:(dl_refO+ dl_timing_offset) - NTA offset’ - NTA, where NTA offset’ is the same as legacy NTA offset. In some embodiments, such a value may be zero (e.g., when the propagation delay between the UE and the UL-only node is the same as that between the UE and the anchor node).

[0119] Additionally or alternatively, as also discussed in further detail below, NTA offset’ may be a modified version of NTA offset, in which the modification is based on a dl timing offset. For example, in some embodiments, the UL timing may be obtained based on the following expression: dl_refO - (NTA offset - dl_timing_offset) - NTA, where, NTA offset’ = (NTA offset - dl_timing_offset).

[0120] Note that in the context of UL-only nodes, NTA offset may correspond to a propagation delay difference with respect to a first propagation delay between the UE and the UL-only node and a second propagation delay difference between the UE and the anchor node.

[0121] In some embodiments, the dl timing offset is received through an RRC message. Additionally or alternatively, in some embodiments, the dl timing offset is included in an existing RRC configured information element (IE), e.g., ServingCellConfigCommon IE, TAG- Config IE, RACH-ConfigDedicated IE or alternatively, in a new RRC configured IE, e.g. nonColocateUplinkConfig IE.

[0122] Additionally or alternatively, in some embodiments, the dl timing offset can be a fixed offset specified in the specification. For example, the dl timing offset may be set to 3ps, or it may be linked to other system parameters e.g., subcarrier spacing.

[0123] In these and other embodiments, the dl timing offset may be included in system information messages. Additionally or alternatively, the dl timing offset may be adapted based on UL timing from earlier random access at the UL-only node / TRP.

[0124] In these and other embodiments, the dl timing offset may correspond to the maximum allowed or estimated time alignment error (TAE) between the TRPs (e.g., between the anchor TRP 802 and the UL only TRP 804 of Figure 8). In some examples, the estimated time alignment error may be reported by the UE.

[0125] Additionally or alternatively, in some embodiments, separate PRACH format and configurations can be configured for the UL-only TRP with the dl timing offset and the anchor TRP without the dl timing offset.

[0126] In some embodiments, multiple di timing offsets can be configured for application to different UL-only node(s) or to the same UL-only node at different times. Additionally or alternatively, in some embodiments the determination of the dl timing offset in addition to the TAE also includes timing impact from one or more of: UE initial transmission error (Te in 3GPP 38.133) and propagation delay estimates (e.g., TP_1 and TP_2 in Figure 8).

[0127] In some embodiments, propagation delay estimates may be based on e.g. randomaccess communications to the anchor node and its accumulated TA (e.g., related to TP_2 part in Figure 8), anchor node cell range, estimated UE position relative to the anchor node and the UL-only node, UL-only node cell range, relative distance between the anchor node and the UL- only node, etc. In some embodiments, if for a serving cell (e.g., the serving cell 800 of Figure 8) the UE is provided two coresetPoolIndex values 0 and 1 for first and second CORESETs, the dl timing offset can be tied to either coresetPoolIndex value 0 or value 1. In some embodiments, the dl timing offset can be applied to the UL signal / channel scheduled with the associated coresetPoolIndex.

[0128] In some embodiments, the application of the dl timing offset may be indicated in a PDCCH order which triggers e.g., contention free random access (CFRA) RACH. In these and other embodiments, it can be a new bitfield in a PDCCH order, or a re-use of an existing bitfield. For example, in some embodiments, if the bitfield = 1, it means the dl timing offset should be applied when transmitting the request PRACH, and if the bitfield = 0, it means the dl timing offset should not be applied when transmitting the request PRACH. This signaling may be useful if the PRACH is the first signal the UE transmits to the UL-only node.

[0129] As a further example, in NR release 18 (Rel-18), when two-time advance groups (TAGs) are configured in the serving cell, for PRACH triggered by a PDCCH order, a one-bit indicator can be included in the PDCCH order to indicate a DL RSs for computing a pathloss to be used for determining a transmit power of the triggered PRACH. If the bit is set to ‘O’, the quais co-location (QCL) source RS associated to the PDCCH is used, otherwise if the bit is set to ‘1’, the SSB indicated in the same PDCCH order is used. In some embodiments, the same bit may be reused for indicating whether the ‘dl timing offset’ is applied to the PRACH, e.g., the ‘dl timing offset’ is applied when the bit is set to ‘ 1’ . This may be applicable at least when a single PCI (physical cell identity) is configured for the serving cell.

[0130] Additionally or alternatively, in some embodiments, the dl timing offset may be associated to a UL Transmission Configuration Indication (TCI) state, where a flag parameter (applyDLtiming offset rxx) may be provided in the IE TCI-UL-State to indicate the application of the dl timing offset. This may be useful to the UL transmission after the UE receives RRC configurations about communication towards the UL-only node. In some embodiments, the said flag parameter enables the application of the dl timing offset to all UL signals / channels associated to the TCI UL state, e.g., the DL reference timing is delayed with the di timing offset when the transmit UL signal / channel is associated to this UL TCI state. In some embodiments, only a part of UL signals / channels associated to the UL TCI state is enabled by the flag parameter. In some embodiment, the activation of the UL TCI state and accordingly the dl timing offset is conveyed via a Medium Access Control (MAC) CE message

[0131] Below is an example implementation of the above with respect to a TCI-UL-State IE. The portion related to applyDLtiming offset rxx is bolded for emphasis.- ASN1 START- TAG-TCI-UL-STATE-STARTTCI-UL-State-rl7 ::= SEQUENCE { tci-UL-StateId-rl7 TCI-UL-StateId-rl7, servingCellId-rl7 ServCelllndex OPTIONAL, - Need R bwp-Id-rl7 BWP-Id OPTIONAL, - Cond CSI-RSorSRS-Indicated referenceSignal-rl7 CHOICE { ssb-Index-r!7 SSB-Index, csi-RS-Index-r!7 NZP-CSI-RS-Resourceld, srs-r!7 SRS-Resourceld additionalPCI-r 17 AdditionalPCIIndex-r 17 OPTIONAL, - Need R ul-powerControl-r 17 Uplink-powerControlId-r 17 OPTIONAL, - Need R pathlossReferenceRS-Id-r!7 PathlossReferenceRS-Id-rl7 OPTIONAL, — Cond Mandatory[[ applyDLtiming-offset-rxx ENUMERATED{enabled} OPTIONAL}- TAG-TCI-UL-STATE-STOP- ASN1STOP

[0132] In these and other embodiments, the network varies the value of the dl timing offset to be applied by the UE and the demodulation performance is observed at the UL-only TRP or TRPs. If the demodulation performance at the UL-only TRP or TRPs is improved, e.g., higher throughput for same code rate (MCS), then the new dl timing offset value is kept. If demodulation performance decreases at UL-only TRP or TRPs for same code rate (MCS), then a previous (e.g., the original) dl timing offset is restored. The variation of the dl timing offset then becomes a matter of finding a maximum throughput (for same code rate, MSC) for some dl timing offsets and this can be done through many techniques like methods from numerical analysis or AI / ML algorithms.

[0133] In some embodiments, the application of the dl timing offset may be performed through modification of legacy NTA offset. For example, in some embodiments NTA offset’ for the UL-only node may be expressed as follows:(NTA offset’= NTA offset - dl_timing_offset), where NTA offset is the same as that used for legacy.• In some embodiments, the dl timing offset is received though RRC message• In some embodiments, the dl timing offset is a fixed offset specified in the specification• In some examples, the dl timing offset is maximum allowed time alignment error between the TRPs• In some embodiments, the dl timing offset can be activated and updated via a medium access control (MAC) communication (e.g., MAC control element (MACCE) with corresponding TAG ID and / or a CORESETPoolIndex.

[0134] In some embodiments, NTA offset’ is a fixed value specified in the specification specifically for transmission towards UL only TRP. Note: Changing the NTA offset’ and UL time at the TRP in general and related TDD guard periods, for that legacy NTA offset’ may not be able to be kept and regulated by normal TA procedure (e.g. to not cause additional TDD interference and be compatible with 3GPP specified switching times).

[0135] In some embodiment, NTA offset’ may be associated to a UL TCI state, in which a flag parameter is provided in the IE TCI-UL-State to indicate the application of NTA offset’. This may improve UL transmissions after UE receives the RRC configurations about communication towards UL-only node.

[0136] Below is an example implementation of the above with respect to a TCI-UL-State Information Element (IE). The portion related to applyNTA_offsetX_rxx is bolded for emphasis:- ASN1 START- TAG-TCI-UL-STATE-STARTTCI-UL-State-rl7 ::= SEQUENCE { tci-UL-StateId-rl7 TCI-UL-StateId-rl7, servingCellId-rl7 ServCelllndex OPTIONAL, - Need R bwp-Id-rl7 BWP-Id OPTIONAL, - Cond CSI-RSorSRS-Indicated reference Signal-r 17 CHOICE { ssb-Index-rl7 SSB-Index, csi-RS-Index-rl7 NZP-CSI-RS-Resourceld, srs-rl7 SRS-Resourceld additionalPCI-r 17 AdditionalPCIIndex-r 17 OPTIONAL, - Need R ul-powerControl-r 17 Uplink-powerControlId-r 17 OPTIONAL, - Need R pathlossReferenceRS-Id-rl7 PathlossReferenceRS-Id-r 17 OPTIONAL, - CondMandatory applyNTA offsetX-rxx ENUMERATED {enabled} OPTIONAL}- TAG-TCI-UL-STATE-STOP- ASN1STOP

[0137] In some embodiments, if for a serving cell, the UE is provided two coresetPoolIndex values 0 and 1 for first and second CORESETs, the application of NTA offset’ can be tied to either coresetPoolIndex value 0 or value 1. Additionally or alternatively, the network may vary the value of NTA offset’ to be applied by the UE and the demodulation performance is observed at the UL-only TRP or TRPs. If the demodulation performance at the UL-only TRP or TRPs is improved, e.g., higher throughput for same code rate (MCS), then the new NTA offset’ value may be kept. If demodulation performance decreases at UL-only TRP or TRPs for same code rate (MCS), then a previous NTA offset’ may be restored. The variation ofNTA offset’ then becomes a matter of finding a maximum throughput (for same code rate, MSC) for some NTA offset’ and this can be done through many techniques like methods from numerical analysis or AI / ML algorithms.

[0138] Below is an example as to how one or more of the embodiments discussed above may help solve the synchronization problem between the UL-only TRPs and anchor TRPs. The below example is discussed with respect to Figure 11. Figure 11 is a block diagram illustrating a scenario of UL transmissions 1100 using the DL reference timing of an anchor TRP and an offset delay.

[0139] In this example, the UE applies a fixed offset of 3ps (shown as CP+SEQ = 903 ps in Figure 11) as the DL timing offset (e.g., which may be the maximum TAE between the TRPs). This example of a value for the fixed offset could be derived from 3GPP specification for TDD cell phase synchronization.

[0140] NW has to receive the entire RACH CP+SEQ within the slot boundary. For the above example, there exists a guard period (GP) of 97ps and by applying the maximum TAE as offset, RACH may start later than the RACH reception window and thereby may result in a reduced GP. For example, if we consider the case where TRP0 and TRP 1 are at same timing sync (scenario 1 discussed in relation to Figure 9), if we apply a timing offset of 3ps, then the effective guard period will be reduced by 3ps. That means the remaining guard period may be sufficient to take care of propagation delays corresponding to distances up to 28.2 kilometers (km). If we consider that TRP1 time is before TRP0 (scenario 2 discussed in relation to Figure 9) with a TAE of 3ps, then there may be a 3ps further reduction of the guard period corresponding to a propagation delay corresponding to distances of 27.3km. Table 1 illustrates example changes in the guard period for different scenarios in which a timing offset of 3ps may be used.Table 1:

[0141] Based on Table 1, all the scenarios other than preamble format Bl, applying fixed offset of 3ps as an example (corresponding to compensation for a TAE=3ps) works well and leaves sufficient GP for propagation delay corresponding to at least 300 meters (B2 preamble format and scenario 2). Since UL-only TRPs are assumed to be used when UEs are close to a UL-only TRP, total propagation delay (TP_1 and TP_2 in Figure 8) may not correspond to more than 300 meters.

[0142] The NW may select the preamble format for the UL-only node that has sufficient guard period when using a determined dl timing offset. In some embodiments, the NW may indicate for which preamble format the UE may use when applying a determined offset to derived DL reference timing and which preamble format that may not be used

[0143] In some embodiments, a time gap may be allowed for the UE to apply the update / activation / switch using the dl timing offset before it performs uplink transmission according to the dl timing offset. The time gap may be pre-defined in a specification, or may be configured by higher layer signaling, including RRC or MACCE. The value of the time gap may be dependent on the configuration in system parameters, e.g. numerology dependent. The value may be defined with time unit of slots, Orthogonal Frequency Division Multiplexing (OFDM) symbols, or milliseconds. The starting point of time gap may include one or more or combination of the following points in time:• Time and slot when PDCCH order is received at the UE.• Time and slot when acknowledge / negative acknowledge (ACK / NACK) for MACCE is received at network.• Time and slot when RRC confirmation is received at network.

[0144] Figure 12 illustrates an example method 1200 that may be performed by a UE with respect to UL transmit timing control for UL-only NW nodes, in accordance with one or more embodiments of the present disclosure.

[0145] One or more operations of the method 1200 may be implemented by a user equipment such as the UE 112A-112D of Figure 1 or the UE 200 of Figure 2. Although illustrated as discrete steps, various steps of the method 1200 may be divided into additional steps, combined into fewer steps, or eliminated, depending on the desired implementation. Additionally, the order of performance of the different steps may vary depending on the desired implementation.

[0146] In some embodiments, the method 1200 may start at block 1202. At block 1202, a UL communication for reception at a first NW node may be sent. The sending of the UL communication may include applying a first timing offset to a UL timing for communication of the UL communication. The first timing offset may account for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to a second NW node used to determine the UL timing.

[0147] Figure 13 illustrates an example method 1300 that may be performed by a network node with respect to UL transmit timing control for UL-only NW nodes, in accordance with one or more embodiments of the present disclosure.

[0148] One or more operations of the method 1300 may be implemented by a network node such as the network node 110A-110B of Figure 1 or the network node 300 of Figure 3. Although illustrated as discrete steps, various steps of the method 1300 may be divided into additional steps, combined into fewer steps, or eliminated, depending on the desired implementation. Additionally, the order of performance of the different steps may vary depending on the desired implementation.

[0149] In some embodiments, the method 1300 may start at block 1302. At block 1302, a UL communication may be received at a first NW node. A timing of receiving the UL communication may be based on application of a first timing offset to a UL timing for communication of the UL communication. The first timing offset may account for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to second NW node used to determine the UL timing.

[0150] Additional details regarding UL timing differences in NR are described below. In NR, the UL signal s / channel PUCCH / PUSCH / SRS transmission may implement a proper TA control with respect to the DL reference timing. Both multi-DCI (mDCI) based intracell multi- TRP operation introduced in Rel-16 and its extension inter-cell multi-TRP in Rel-17 assume that the timing difference between signals received from the two TRPs is within a cyclic prefix (CP) length and that UE can transmit signals towards the two TRPs using the same TA. To handle larger UL timing differences (>CP) at a UE between two TRPs, the two-TA feature is introduced in Rel-18 for multi-DCI based multi-TRP, where separate timing advance control is supported, and each can be applied to UL transmission to a TRP. Difference between transmit timing to two TRPs can be up to 34.5 ps if UE supports the capability. The asymmetric DL sTRP / UL mTRP deployment may assume intraband intra-DU non-collocated mTRPs, hence the Rel-18 assumption on timing difference larger than CP is applied to the Rel-19 asymmetric mTRP scenario.

[0151] The timing difference range between the Anchor TRP and the UL-only TRP can re-use the assumption from the Rel-18 two-TA framework, i.e., timing difference larger than CP (MRTD=33ps / 8ps and MTTD=34.5ps / 8.5ps for FR1 / FR2).

[0152] The Rel-18 two-TA feature may be limited to multi-DCI based multi-TRP under the Rel-18 unified TCI state framework. In addition, the Rel-18 two-TA feature relies on the legacy concept of timing advance group (TAG), with enhancement that a UE can be configured with two TAGs in a serving cell. More specifically, each TAG is associated with UL transmission towards one of the two TRPs, where the mapping between UL channel s / signals to a TAG is linked to the TCI state. Hence, a TA is applied to UL transmissions according to the TAG configured in the TCI state(s). The downlink timing refence signal of the TAG can be provided as a SSB signal configured in one of the TCI states associated to the TAG.

[0153] The Rel-18 two-TA feature may be limited to multi-DCI based multi-TRPs where a serving cell can be configured with two TAGs via the TCI states.

[0154] Each of the two TAs (and the associated two TAGs) in the Rel-18 two-TA feature may be associated to a DL timing reference signal.

[0155] For UL-only TRP in Rel-19, the WID limits the scope to single-TRP operation in DL, and hence reusing the Rel-18 multi-DCI two-TA solution for UL-only TRP deployments seems to be inadequate since multi-DCI multi-TRP operation is mainly motivated by DL multi- TRP operation with poor synchronization across DL TRPs. If the Rel-18 multi-DCI two-TA solution is used, a UE can support multi-DCI operation to enable UL-only TRP operation, which is an undesired and unnecessary restriction.

[0156] Reusing multi-DCI based two-TA solutions for UL-only node deployment may include UEs supporting UL-only TRPs to also support multi-DCI based operation.

[0157] Another option could be to adapt the Rel-18 multi-DCI based two-TA solutions to single-DCI(sDCI) operation. To do this, only minor changes for the Rel-18 two-TA solution may occur, e.g., removing the association between a TAG and CORESETPooIndex, and using a single DL timing reference signal (from the Anchor TRP) for both TAs, instead of using two DL reference signals as in the Rel-18 multi-DCI two-TA solution. Of the two options, the latter is much more attractive. Based on the above discussion, we have the following proposals to include enhancement to enable two-Tas for asymmetric DL sTRP UL mTRP scenarios in the Rel-19 scope.

[0158] RAN 1 consider to support enhancement to enable two-TAs for asymmetric DL sTRP UL mTRP scenario in the Rel-19 scope.

[0159] A UE can be at different propagation delay with regard to each TRP and after the initial transmit timing control (i.e., after performing PRACH), the UE can properly manage two separate TA loops to set UL timing towards the non-collocated TRPs, based on separate Timing Advance Commands, with respect to Anchor TRP DL timing reference. In other words, to enable two TAs with respect to two TRPs, a UE may obtain DL reference timing and UL TA command towards UL-only TRP. The two-TA feature in Rel-18 assumes non-ideal synchronization (i.e., TRPs slot boundaries are not perfectly time aligned and there can be synchronization error of up to e.g., 3ps) between the TRPs. As per the WID, asymmetric and non-collocated deployment may be supported for UL-only TRP. That means the synchronization assumptions in Rel-18 may be applied for Rel-19 UL-only TRP also as operators may not deploy separate TRPs for using the UL-only TRP feature (e.g., operators may use same deployment for Rel-18 and Rel-19).

[0160] As UL-only TRP do not transmit any SSB, UE may rely on Anchor TRP SSB to derive the DL reference timing. When slot boundaries of Anchor TRP and UL-only TRP are perfectly aligned in time (i.e., synchronization error is Ops), UE may use the DL reference timing of Anchor TRP to perform random access procedure and obtain TA command to handle the asymmetric propagation delay difference between Anchor TRP to UE and UL-only TRP to UE.

[0161] However, in the practical deployments (such asymmetric deployments considered in this WI) it may not be always possible to maintain perfect synchronization between different TRPs (even for intra-DU deployments as most of the NW deployments use something called switched fronthaul). When UL-only TRP is ahead of Anchor TRP slot timing, when UEacquires DL timing from Anchor TRP and transmits PUSCH using the same DL reference timing, it may result in inter-slot interference at UL-only TRP.

[0162] Based on the above discussion, a UE may consider practical synchronization error between Anchor TRP and UL only TRP for UL and DL timing control in an asymmetric deployment.

[0163] RAN 1 may consider practical synchronization error between Anchor TRP and UL- only TRP for UL and DL timing control in asymmetric DL sTRP UL mTRP deployment.

[0164] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0165] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform thedescribed functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

Claims

CLAIMSWhat is claimed is:

1. A method performed by a user equipment (UE) for sending an uplink (UL) communication, the method comprising: sending (1202) a UL communication for reception at a first network (NW) node, the sending of the UL communication including applying a first timing offset to a UL timing for communication of the UL communication, the first timing offset accounting for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to a second NW node used to determine the UL timing.

2. The method of claim 1, wherein the possible time alignment error includes: the first UL slot boundaries being ahead in time with respect to the second UL slot boundaries; or the first UL slot boundaries being behind in time with respect to the second UL slot boundaries.

3. The method of any of claims 1-2, wherein the UL timing is further based on a second timing offset corresponding to a propagation delay difference with respect to: a first propagation delay between the UE and the first NW node; and a second propagation delay between the UE and the second NW node.

4. The method of claim 3, wherein one or more of: the second timing offset has a value of zero; the second timing offset corresponds to a legacy timing adjustment offset value (NTA offset); or applying the first timing offset to the UL timing includes modifying the second timing offset based on the first timing offset.

5. The method of any of claims 1-4, wherein one or more of: the UE receives the first timing offset through a received communication; the first timing offset is a fixed offset; the first timing offset is a variable offset; the first timing offset is based on a threshold allowed distance between the first NWnode and UEs; the first timing offset is based on a guard period size between UL communication slots; the first timing offset is adapted based on one or more UL communications between the UE and the first NW node; the first timing offset is based on an estimated time alignment error between the first UL slot boundaries and the second UL slot boundaries; or the first timing offset is based on a threshold allowed time alignment error between the first UL slot boundaries and the second UL slot boundaries.

6. The method of claim 5, wherein the received communication includes one or more of a Radio Resource Control (RRC) communication; a Physical Downlink Control Channel communication; a Medium Access Control (MAC) communication; a Transmission Configuration Indication communication; or a System Information (SI) communication.

7. The method of claim 5, wherein the one or more UL communications include at least one random access communication.

8. The method of any of claims 1-7, wherein the first timing offset is applied to the UL communication in response to an instruction included in a DL signal received by the UE.

9. The method of claim 8, wherein the instruction corresponds to one or more of a Physical Downlink Control Channel (PDCCH) communication; or a Transmission Configuration Indication (TCI) communication.

10. The method of any of claims 1-9, wherein the first timing offset is determined based on one or more previous UL communications previously sent by the UE and received by the first NW node.

11. The method of claim 10, wherein the first timing offset is determined based on demodulation performance of the one or more previous UL communications.

12. The method of any of claims 1-11, wherein the UL timing allows for a time gap for theUE to apply the first timing offset.

13. The method of any of claims 1-12, further comprising using a different format for one or more UL communication slots to the first NW node than for the second NW node.

14. The method of claim 13, wherein the one or more UL communication slots include UL communication slots corresponding to Physical Random Access Control Channel (PRACH) communications.

15. The method of any of claims 1-14, wherein the first NW node is a UL-only NW node and the second NW node is a downlink / uplink (DL / UL) NW node.

16. A method performed by a network node for receiving an uplink (UL) communication, the method comprising: receiving (1302), at a first network (NW) node, a UL communication, a timing of receiving the UL communication being based on application of a first timing offset to a UL timing for communication of the UL communication, the first timing offset accounting for a possible time alignment error between first UL slot boundaries corresponding to the first NW node and second UL slot boundaries corresponding to second NW node used to determine the UL timing.

17. The method of claim 16, wherein the possible time alignment error includes: the first UL slot boundaries being ahead in time with respect to the second UL slot boundaries; or the first UL slot boundaries being behind in time with respect to the second UL slot boundaries.

18. The method of any of claims 16-17, wherein the UL timing is further based on a second timing offset corresponding to a propagation delay difference with respect to: a first propagation delay between user equipment (UE) and the first NW node; and a second propagation delay between the UE and the second NW node.

19. The method of claim 18, wherein one or more of: the second timing offset has a value of zero;the second timing offset corresponds to a legacy timing adjustment offset value (NTA offset); or applying the first timing offset to the UL timing includes modifying the second timing offset based on the first timing offset.

20. The method of any of claims 16-19, wherein one or more of: the UE receives the first timing offset through a received communication; the first timing offset is a fixed offset; the first timing offset is a variable offset; the first timing offset is based on a threshold allowed distance between the first NW node and UEs; the first timing offset is based on a guard period size between UL communication slots; the first timing offset is adapted based on one or more UL communications between the UE and the first NW node; the first timing offset is based on an estimated time alignment error between the first UL slot boundaries and the second UL slot boundaries; or the first timing offset is based on a threshold allowed time alignment error between the first UL slot boundaries and the second UL slot boundaries.

21. The method of claim 20, wherein the received communication includes one or more of: a Radio Resource Control (RRC) communication; a Physical Downlink Control Channel communication; a Medium Access Control (MAC) communication; a Transmission Configuration Indication communication; or a System Information (SI) communication.

22. The method of claim 20, wherein the one or more UL communications include at least one random access communication.

23. The method of any of claims 16-22, wherein the first timing offset is applied to the UL communication in response to an instruction included in a DL signal received by the UE.

24. The method of claim 23, wherein the instruction corresponds to one or more of: a Physical Downlink Control Channel (PDCCH) communication; ora Transmission Configuration Indication (TCI) communication.

25. The method of any of claims 16-24, wherein the first timing offset is determined based on one or more previous UL communications previously sent by the UE and received by the first NW node.

26. The method of claim 25, wherein the first timing offset is determined based on demodulation performance of the one or more previous UL communications.

27. The method of any of claims 16-26, wherein the UL timing allows for a time gap for the UE to apply the first timing offset.

28. The method of any of claims 16-27, further comprising using a different format for one or more UL communication slots to the first NW node than for the second NW node.

29. The method of claim 28, wherein the one or more UL communication slots include UL communication slots corresponding to Physical Random Access Control Channel (PRACH) communications.

30. The method of any of claims 16-29, wherein the first NW node is a UL-only NW node and the second NW node is a downlink / uplink (DL / UL) NW node.

31. A user equipment for sending an uplink (UL) communication, comprising: processing circuitry configured to perform any of the steps of any of claims 1-15; and power supply circuitry configured to supply power to the processing circuitry.

32. A base station for receiving an uplink (UL) communication, the base station comprising: processing circuitry configured to perform any of the steps of any of claims 16-30; and power supply circuitry configured to supply power to the processing circuitry.

33. A user equipment (UE) for sending an uplink (UL) communication, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processingcircuitry; the processing circuitry being configured to perform any of the steps of any of claims 1- 15; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

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