User equipment representation in open radio access network fronthaul

Abstract

A method performed by a network node is provided. The method comprises configuring a first portion of bits from an identification field comprising multiple bits to represent one or more UEs. The method further comprises configuring a second portion of bits from remainder of the identification field to represent one or more user layers associated with the one or more UEs. The method further comprises sending the identification field comprising the first portion of bits and the second portion of bits via a fronthaul interface protocol.

Description

USER EQUIPMENT REPRESENTATIONIN OPEN RADIO ACCESS NETWORK FRONTHAUECROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 531,523 filed on August 8, 2023, titled “UE Representation In C-Plane Messaging In O- RAN Open Fronthaul”. The content of the application is hereby incorporated by reference in its entirety for all purposes.FIELD

[0002] The present disclosure relates generally to communication systems and, more specifically, to methods and systems for user equipment (UE) representation in Control-Plane (C -Plane) messaging in Open Radio Access Network (O-RAN) open fronthaul.BACKGROUND

[0003] Massive multiple-input multiple-output (Massive MIMO) technologies were initially adopted in LTE (Long-Term Evolution). In 5G (Fifth Generation), Massive MIMO becomes a key technology component, which is deployed on a much larger scale than in LTE.

[0004] Massive MIMO technologies significantly increase spectrum efficiency and cell capacity of a cellular network. Massive MIMO utilizes a substantial number of antennas on the base-station side. The number of antennas is typically much larger than the number of userlayers. Massive MIMO also forms narrow beams focusing on different directions to counteract the increased path loss at higher frequency bands. In addition, Massive MIMO benefits multiuser MIMO, which allows for transmissions to or from multiple users simultaneously over separate spatial channels, while keeping high capacity for each user.SUMMARY

[0005] Massive MIMO technology encompasses a variety of beamforming functions designed to enhance performance. Emerging methods, such as Demodulation Reference Signal (DMRS) based beamforming, are among these advancements. These new beamforming techniques often require processing based on reference signal configuration, which is linked to specific user layers and UEs. This disclosure presents innovative systems and methods for efficiently communicating these user layer and UE information via the fronthaul interface.

[0006] In one embodiment, a method performed by a network node is provided. The method comprises configuring a first portion of bits from an identification field comprising multiple bits to represent one or more UEs. The method further comprises configuring a second portion of bits from remainder of the identification field to represent one or more user layers associated with the one or more UEs. The method further comprises sending the identification field comprising the first portion of bits and the second portion of bits via a fronthaul interface protocol.

[0007] In another embodiment, a method performed by a network node for communicating information of one or more UEs via a fronthaul interface protocol is provided. The fronthaul interface protocol comprises a first field. The method comprises configuring the first field to include a number of entries corresponding to a total number of one or more user layers. Each entry corresponds to a user layer of the one or more user layers. The method further comprises configuring each entry to represent an index of a UE in the one or more UEs. The UE is associated with the user layer to which the entry corresponds. The method further comprises sending the first field via the fronthaul interface protocol.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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.

[0009] Figure 1 illustrates an example of a communication system in accordance with some embodiments.

[0010] Figure 2 illustrates an exemplary user equipment in accordance with some embodiments.

[0011] Figure 3 illustrates an exemplary network node in accordance with some embodiments.

[0012] Figure 4 is a block diagram of an exemplary host, which may be an embodiment of the host of Figure 1, in accordance with various aspects described herein.

[0013] Figure 5 is a block diagram illustrating an exemplary virtualization environment in which functions implemented by some embodiments may be virtualized.

[0014] Figure 6 illustrates a communication diagram of an exemplary host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.

[0015] Figure 7 illustrates a fronthaul interface between a distributed unit (DU) and a radio unit (RU) at a base-station in accordance with some embodiments.

[0016] Figure 8 illustrates a Weight-based Dynamic Beamforming (WDBF) implementation in the uplink direction in accordance with some embodiments.

[0017] Figure 9 illustrates a messaging diagram between O-RAN distributed unit O-DU and O-RAN radio unit (O-RU) using the WDBF beamforming method in accordance with some embodiments.

[0018] Figure 10 illustrates a data structure containing multiple ueld fields in the current O-RAN Working Group 4 specification.

[0019] Figure 11 illustrates an implementation of the first subvariant of Demodulation Reference Signal based beamforming with equalization (DMRS-BF-EQ) in accordance with some embodiments.

[0020] Figure 12 illustrates an implementation of the second subvariant of Demodulation Reference Signal based beamforming with equalization (DMRS-BF-EQ) in accordance with some embodiments.

[0021] Figure 13 illustrates an implementation of Demodulation Reference Signal based beamforming without equalization (DMRS-BF-NEQ) in accordance with some embodiments.

[0022] Figure 14 illustrates a messaging diagram between O-DU and O-RU using the DMRS-BF beamforming method in accordance with some embodiments.

[0023] Figure 15 illustrates an example for configuring the UE identification field (ueld) in accordance with some embodiments.

[0024] Figure 16 illustrates another example for configuring the UE identification field (ueld) in accordance with some embodiments.

[0025] Figure 17 illustrates an example for configuring a new field in C-plane messaging with four entries in accordance with some embodiments.

[0026] Figure 18 illustrates a flowchart showing a method for communication performed by a network node in accordance with some embodiments.

[0027] Figure 19 illustrates a flowchart showing another method for communication via a fronthaul interface protocol performed by a network node in accordance with some embodiments.DETAILED DESCRIPTION

[0028] To provide a more thorough understanding of the present invention, the following description sets forth numerous specific details, such as specific configurations, parameters,examples, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is intended to provide a better description of the exemplary embodiments.

[0029] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise:

[0030] 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 or spirit of the invention.

[0031] 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.

[0032] The term “based on” is not exclusive and allows for being based on additional factors not described unless the context clearly dictates otherwise.

[0033] 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.

[0034] In addition, throughout the specification, the meaning of “a”, “an”, and “the” includes plural references, and the meaning of “in” includes “in” and “on”.

[0035] 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.

[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 110b (one or more of which may be generally referred to as network nodes 110), or any other similar 3rdGeneration Partnership Project (3GPP) 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 (O-RAN) network nodes. An O-RAN network node is a node in the telecommunication network 102 that supports an O- RAN 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 O-RAN network node include an O-RAN radio unit (O-RU), an O-RAN 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 anon-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an O-RAN 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 O-RAN access node may be a logical node in a physical node. Furthermore, an O-RAN 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 user equipment (UE), such as by connecting UEs 112a, 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 transmiting 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 / or any 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 hosts, 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 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, and may be operated by the service provider or on behalf of the service provider. The host 116 may host a variety of applications to provide one or more service. Examples of suchapplications 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 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 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 Micro wave 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 3GPP 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-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, e.g. 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 networknodes (e.g., network node 110b). 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 sends commands 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 headset, 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 110b. 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 110b. 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. 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 consoleor device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (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 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-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 any combination 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 random access 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, externalhard 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-DIMM SDRAM, 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 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, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet 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 connection to 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 head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), 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, or other 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)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU). Note that O-DU and O-CU can be implemented in one physical node.

[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 units, distributed units (e.g., comprising O-RU and O-DU in an O- RAN system design or architecture) and / or digital units, also referred to as baseband units, remote radio units (RRUs), sometimes referred to as Radio Unit (RU), Remote Radio Heads (RRHs), or Radio Heads. Such remote radio units may or may not be integrated with an antennaas 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 radio access technologies (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 radio frequency (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 storage media (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 is 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.

[0076] Figure 4 is a block diagram of a host 400, which may be an embodiment of the host 116 of Figure 1, in accordance with various aspects described herein. As used herein, the host 400 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 400 may provide one or more services to one or more UEs.

[0077] The host 400 includes processing circuitry 402 that is operatively coupled via a bus 404 to an input / output interface 406, a network interface 408, a power source 410, and a memory 412. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 2 and 3, such that the descriptions thereof are generally applicable to the corresponding components of host 400.

[0078] The memory 412 may include one or more computer programs including one or more host application programs 414 and data 416, which may include user data, e.g., data generated by a UE for the host 400 or data generated by the host 400 for a UE. Embodiments of the host 400 may utilize only a subset or all of the components shown. The host application programs 414 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 414 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 400 may select and / or indicate a different host for over-the-top services for a UE. Thehost application programs 414 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0079] Figure 5 is a block diagram illustrating a virtualization environment 500 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 500 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 500 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.

[0080] Applications 502 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0081] Hardware 504 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 506 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 508a and 508b (one or more of which may be generally referred to as VMs 508), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 506 may present a virtual operating platform that appears like networking hardware to the VMs 508.

[0082] The VMs 508 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 506. Different embodiments of the instance of a virtual appliance 502 may be implemented on oneor more of VMs 508, 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.

[0083] In the context of NFV, a VM 508 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 508, and that part of hardware 504 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 508 on top of the hardware 504 and corresponds to the application 502.

[0084] Hardware 504 may be implemented in a standalone network node with generic or specific components. Hardware 504 may implement some functions via virtualization. Alternatively, hardware 504 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 510, which, among others, oversees lifecycle management of applications 502. In some embodiments, hardware 504 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 512 which may alternatively be used for communication between hardware nodes and radio units.

[0085] Figure 6 shows a communication diagram of a host 602 communicating via a network node 604 with a UE 606 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 112a of Figure 1 and / or UE 200 of Figure 2), network node (such as network node 110a of Figure 1 and / or network node 300 of Figure 3), and host (such as host 116 of Figure 1 and / or host 400 of Figure 4) discussed in the preceding paragraphs will now be described with reference to Figure 6.

[0086] Like host 400, embodiments of host 602 include hardware, such as a communication interface, processing circuitry, and memory. The host 602 also includes software, which is stored in or accessible by the host 602 and executable by the processingcircuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 606 connecting via an over-the-top (OTT) connection 650 extending between the UE 606 and host 602. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 650.

[0087] The network node 604 includes hardware enabling it to communicate with the host 602 and UE 606. The connection 660 may be direct or pass through a core network (like core network 106 of Figure 1) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0088] The UE 606 includes hardware and software, which is stored in or accessible by UE 606 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 606 with the support of the host 602. In the host 602, an executing host application may communicate with the executing client application via the OTT connection 650 terminating at the UE 606 and host 602. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 650 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 650.

[0089] The OTT connection 650 may extend via a connection 660 between the host 602 and the network node 604 and via a wireless connection 670 between the network node 604 and the UE 606 to provide the connection between the host 602 and the UE 606. The connection 660 and wireless connection 670, over which the OTT connection 650 may be provided, have been drawn abstractly to illustrate the communication between the host 602 and the UE 606 via the network node 604, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0090] As an example of transmitting data via the OTT connection 650, in step 608, the host 602 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 606. In other embodiments, the user data is associated with a UE 606 that shares data with the host 602 without explicit human interaction. In step 610, the host 602 initiates a transmission carrying the user data towards the UE 606. The host 602 may initiate the transmission responsive to a request transmitted by the UE 606. The request may be caused by humaninteraction with the UE 606 or by operation of the client application executing on the UE 606. The transmission may pass via the network node 604, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 612, the network node 604 transmits to the UE 606 the user data that was carried in the transmission that the host 602 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 614, the UE 606 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 606 associated with the host application executed by the host 602.

[0091] In some examples, the UE 606 executes a client application which provides user data to the host 602. The user data may be provided in reaction or response to the data received from the host 602. Accordingly, in step 616, the UE 606 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 606. Regardless of the specific manner in which the user data was provided, the UE 606 initiates, in step 618, transmission of the user data towards the host 602 via the network node 604. In step 620, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 604 receives user data from the UE 606 and initiates transmission of the received user data towards the host 602. In step 622, the host 602 receives the user data carried in the transmission initiated by the UE 606.

[0092] One or more of the various embodiments improve the performance of OTT services provided to the UE 606 using the OTT connection 650, in which the wireless connection 670 forms the last segment. More precisely, the teachings of these embodiments may improve the e.g., data rate, latency, power consumption and thereby provide benefits such as e.g., reduced user waiting time, relaxed restriction on file size, improved content resolution, better responsiveness, extended battery lifetime, and a more efficient transmission of the target-CSI.

[0093] In an example scenario, factory status information may be collected and analyzed by the host 602. As another example, the host 602 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 602 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 602 may store surveillance video uploaded by a UE. As another example, the host 602 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 602 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (suchas compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.

[0094] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 650 between the host 602 and UE 606, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 602 and / or UE 606. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 650 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 650 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 604. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 602. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 650 while monitoring propagation times, errors, etc.

[0095] Figure 7 illustrates a fronthaul interface between a distributed unit (DU) and a radio unit (RU) at a base station in accordance with some embodiments. As shown in the figure, at the base-station (or the network node) side, the interface between the DU and the RU is the fronthaul interface. The legacy Common Public Radio Interface (CPRI)-type fronthaul transports time-domain in-phase quadrature (IQ) samples per antenna branch. As the number of antennas scales up in Massive MIMO systems, the required fronthaul capacity also increases proportionally, which significantly drives up the fronthaul costs. To address this new challenge on the base-station side, the fronthaul interface evolves from CPRI to eCPRI, a packet-based fronthaul interface. In eCPRI, other functional split options between a DU and an RU are supported, which are referred to as different lower-layer split (LLS) options. In the eCPRI standard specification, the terms eREC (eCPRI Radio Equipment Control) and eRE (eCPRI Radio Equipment) are used instead of DU and RU. The basic concept involves moving the frequency -domain beamforming function from DU to RU. As a result, frequency-domain IQ samples or data of user-layers are transported over the fronthaul interface. In this context, thefrequency -domain beamforming is sometimes referred to as “precoding” in the downlink (DL) direction and “equalizing” or “pre-equalizing” in the uplink (UL) direction. It should be noted that a “user-layer” or “user layer” in this disclosure refers to an independent downlink or uplink data stream that is intended for one user. One user or UE may have one or more user layers. For simplicity, “user layer” may also be referred to as “layer” in this disclosure.

[0096] By moving the frequency-domain beamforming function from DU to RU, the required fronthaul capacity and fronthaul costs can be significantly reduced. This is because the number of user layers or the number of spatial streams after frequency domain beamforming is typically much fewer than the number of antennas in Massive MIMO. In Open Radio Access Network (O-RAN), DU is referred to as O-DU while RU is referred to as O-RU. This disclosure focuses on the uplink direction of the fronthaul interface. But it can be used for the downlink direction of the fronthaul interface as well.

[0097] Figure 8 illustrates a Weight-based Dynamic Beamforming (WDBF) implementation in the uplink direction in accordance with some embodiments. The WDBF implementation is supported by O-RAN WG4 (Working Group 4) specification (e.g., O-RAN WG4 (Open Fronthaul Interfaces WG) Control, User and Synchronization Plane Specification, O-RAN. WG4.CUS.0-R003-vl2.00). By implementing the beamforming function in the O-RU, the number of spatial streams transmitted through the fronthaul interface is reduced, compared to the number of antenna branches. However, the beamforming weights are calculated in the O-DU based on the Sounding Reference Signal (SRS) signal sent back from the O-RU. Since the SRS channel estimates correspond to a previous channel, the number of required streams remains significantly higher than the number of layers to prevent performance loss, compared to using CPRI-based fronthaul. There is a tradeoff between the number of streams used and the overall performance, e.g., user throughput, cell throughput etc.

[0098] Figure 9 illustrates a messaging diagram between O-DU and O-RU using the WDBF beamforming method in accordance with some embodiments. This messaging diagram is also included in the current O-RAN WG4 specification. As shown in the figure, in slot #n, the O-DU transmits C-plane scheduling commands to communicate scheduling information to the O-RU (reference 901). The scheduling information may include REs (Resource Elements) to be scheduled, the beam ID (referred to as beamld in the O-RAN WG4 specification) which represents the beamforming weights pre-stored and / or currently stored in the O-RU, and the beamforming weights (BFWs) to be used. After receiving the scheduling information, the O- RU processes scheduled REs according to the scheduling information received. For example, the O-RU performs beamforming by applying the beamforming weights received directly orindicated by the beam ID. The O-RU then transmits the processed REs as User-Plane (U-plane) data in U-plane messages to the O-DU (reference 902). This process is repeated in every slot.

[0099] Another type of beamforming methods defined in the current 0-RAN WG4 specification is Channel Information based Beamforming (CIBF). In CIBF, instead of transmitting BFWs or beamld, the O-DU transmits the following information to the O-RU in C-plane messages: scheduled REs, scheduled layers, and SRS channel estimates of the scheduled layers. The O-RU uses the received information to calculate the BFWs and perform beamforming on the scheduled REs using the calculated BFWs. The O-RU then transmits the processed REs as U-plane data in U-plane messages to the O-DU. In the specification, each scheduled layer is represented by a “ueld” field in C-plane message. It should be noted that although the field name is “ueld”, it denotes a layer, not a UE. For a UE with multiple layers scheduled, multiple ueld fields are needed, with each ueld represents one layer of the UE. However, in the current O-RAN specification, the O-RU is not aware that these uelds belong to the same UE. Figure 10 illustrates a data structure containing multiple ueld fields in the current O-RAN WG4 specification. According to the figure, the ueld field defined in C-plane Section Type 5 is 15 bits long.

[0100] O-RAN WG4 also introduces a new beamforming method called Demodulation Reference Signal (DMRS) based beamforming (DMRS-BF). The goal of DMRS-BF is to achieve better performance using minimal fronthaul bit rate. DMRS-BF may reduce the number of streams to the number of layers. There are two implementation variants of DMRS- BF. The first variant is referred to as DMRS based beamforming with equalization (DMRS- BF-EQ), where equalization is performed in O-RU. The second variant is referred to as DMRS based beamforming without equalization (DMRS-BF-NEQ), where equalization is not performed in O-RU.

[0101] In wireless communication, signal distortion can be caused by various factors, including the end-to-end channel, the transmitter chain, the over-the-air channel (which includes both the wanted channel and the interference channel), and the receiver chain. An equalizer performs equalization operations on input signals to reduce signal distortion. After equalization, the equalized symbols can be demodulated by a demodulator. When input signals originate from multiple transmitters sending different data, the equalizer can also mitigate interferences among the transmitters. Equalizers can be categorized as either linear or nonlinear. Examples of linear equalizers include zeroforcing equalizer, and MMSE (Minimum Mean Square Error) equalizer, etc. Examples of non-linear equalizers include decisionfeedback equalizer (DFE), and successive interference cancellation (SIC) receiver, etc.

[0102] The first variant of DMRS-BF, which is DMRS-BF-EQ, has two implementation subvariants. Figure 11 illustrates an implementation of the first subvariant of DMRS-BF-EQ in accordance with some embodiments. In the first subvariant, the O-DU does not perform additional equalization. Instead, the O-RU transmits both the equalized data symbols and the signal-to-interference-and-noise-ratio (SINR) measurement to the O-DU. The O-DU uses the received SINR measurement to demodulate the equalized symbols. The SINR measurement represents the measured or estimated SINR values, which may be provided per physical resource block (PRB), or at a finer frequency resolution per layer. This information is used by the demodulator to demodulate the symbols of each RE per layer, using demodulation algorithms such as log likelihood ratio (LLR). The equalized data symbols are also referred to as “soft values”.

[0103] Figure 12 illustrates an implementation of the second subvariant of DMRS-BF-EQ in accordance with some embodiments. In the second subvariant, the O-DU performs an additional equalization (reference 1201). This subvariant can support advanced receiver algorithms that need channel estimates in the O-DU such as SIC receiver and Interference Rejection Combining - Coordinated Multi-Point (IRC-CoMP) receiver. In this subvariant, O- RU transmits both equalized data symbols and equalized DMRS symbols which are equalized in the same way as the equalized data symbols. The O-DU will use the received equalized DMRS to estimate the effective channel including air interface channel and the O-RU processing (e.g. equalization done by the O-RU). Then, the effective channel estimates are used to further process the data symbols.

[0104] As illustrated in Figures 11 and 12, in the implementations for both subvariants of DMRS-BF-EQ, O-RU transmits RRM (Radio Resource Management) measurements which are calculated or measured before beamforming and equalization (references 1101 and 1202). Since these measurements cannot be calculated in the O-DU, they are performed by the O-RU and then transmitted to the O-DU. Reporting RRM measurements from the O-RU is beneficial. Some examples of RRM measurements include:• Estimate of time of arrival (ToA) of UE signal: This is used for UE Timing Advance (TA). This measurement is one ToA value per UE and measures the UE Timing Advance Error (TAE).• Estimate of received signal power of UE: This is used for UE closed loop power control. This measurement is one value per UE or per UE layer.• Interference plus noise (IPN) power measurement: O-RU calculates the power of received interference and noise per PRB. This is useful for the scheduler in the O-DU to optimize scheduling decisions. There are two kinds of IPN measurements, i.e., IPN for the allocated PRBs and the unallocated PRBs, respectively. The allocated PRBs are the PRBs scheduled for UE traffic, while the non-allocated PRBs are the PRBs with no UE traffic scheduled. This measurement can be one value per PRB or one value per PRB per symbol.• DTX (Discontinuous Transmission) detection result: Better DTX detection performance can be achieved by the O-RU. This measurement is a one-bit value per UE.

[0105] In addition to the list above, RRM measurements may also include delay spread, frequency offset, doppler shift, and AoA (angle of arrival), etc.

[0106] Figure 13 illustrates an implementation of Demodulation Reference Signal based beamforming without equalization (DMRS-BF-NEQ) in accordance with some embodiments. In the implementation, the O-RU performs beamforming but not equalization. The O-RU transmits both beamformed data symbols and beamformed DMRS symbols to the O-DU. The beamformed DMRS symbols are processed in the same way as the beamformed data symbols. The O-DU uses the received beamformed DMRS to estimate effective channels, which include air interface channel and O-RU processing, such as beamforming performed by the O-RU. These effective channel estimates are then used to perform equalization. It is also beneficial for the DMRS-BF-NEQ implementation to report RRM measurements from the O-RU, especially those that cannot be calculated by the O-DU from the received beamformed DMRS symbols, e.g., OTA and frequency offset.

[0107] Table 1 shows the granularity of the RRM measurements listed above and indicates whether they are mandatory or optional for DMRS-BF-EQ and DMRS-BF-NEQ. For optional measurements, it is up to the O-RU vendors to decide whether to support it.Table 1

[0108] Figure 14 illustrates a messaging diagram between O-DU and O-RU using the DMRS-BF beamforming method in accordance with some embodiments. As shown in the figure, in slot #n, the O-DU transmits C-plane scheduling commands and / or measurement commands to the O-RU (reference 1401). In some examples, the O-RU then transmits C-plane measurement reports of slot #n to O-DU (reference 1402). The O-RU also transmits U-plane data of slot #n to O-DU (reference 1403). The actual time when O-RU transmits RRM measurements or U-plane data follow the transmission window defined for measurement data or U-plane. This process is repeated in every slot.

[0109] Because of the support for communicating measurement information, the DMRS- BF beamforming method (including both the DMRS-BF-EQ and DMRS-BF-NEQ variants) has an impact on the uplink C-plane and U-plane data flows. As a result, new C-plane signaling between O-RU and O-DU is needed to provide the necessary information from O-DU to O-RU to perform DMRS-based beamforming (with or without equalization). New C-plane signaling is also needed to provide necessary measurements from O-RU to O-DU to assist O-DU operations, such as Physical Uplink Shared Channel (PUSCH) processing and RRM operations. From O-DU to O-RU, in addition to the information regarding the scheduled REs, the scheduling information need to contain DMRS configuration to be used and UE information representing the UEs and UE layers scheduled, as well as the measurement control. From O- RU to O-DU, in addition to the U-plane messages, the RRM measurements are transmitted in C-plane messages.

[0110] There currently exist certain challenges. In the existing O-RAN WG4 specification, the ueld field is defined to represent the scheduled layers. However, with the existing ueld filed, the O-RU cannot determine whether these layers belong to one UE or multiple UEs. This is sufficient for the current WDBF implementation without using any RRM measurements. However, in new beamforming methods such as DMRS-BF, measurements like To A, RX signal power, DTX detection result, frequency offset, doppler shift, or Ao A, etc., are defined per UE. To calculate these measurements, the O-RU needs to know which layers belong to which UE. For example, when two UEs are scheduled with two layers for each UE, the O-RU needs to identify which two layers correspond to which UE. Then, the O-RU can use the information of all layers for each UE to calculate the measurements. Furthermore, some algorithms may utilize the UE information to optimize processing. Therefore, a new mechanism is needed to communicate the UE information via the fronthaul interface.[oni] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Two new methods are presented in this disclosure to communicate the information regarding the scheduled UEs while reusing the existing definition of ueld. The first method is to specify a rule using a portion of the ueld’s 15 bits to represent UEs and using the remaining bits to represent layers associated with each UE. The second method is to add a field to represent a UE index for each layer (i.e. each ueld) in C-plane messages. This can be achieved, for example, by defining a new Section Extension containing this information, or by adding the field to a new Section Type.

[0112] Certain embodiments may provide one or more of the following technical advantages. One advantage of the first method is that it is possible to reuse the existing Section Type 5 to communicate the scheduling information for DMRS-BF, without the need to define and support a new Section Type with a new mechanism to represent UEs and their layers. One advantage of the second method is to create a clean and simple mechanism that can be used by new section types without the need to use a section extension to add the information relating the existing ueld values to UEs.

[0113] Some 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.

[0114] In one embodiment, the existing 15-bit ueld is split into two parts. A first part represents each UE, and a second part represents each layer of each UE. Figure 15 illustrates an example for configuring the UE identification field (ueld) in accordance with some embodiments. In this example, the first part of the ueld field (the part representing each UE) comprises a most significant bit (MSB) of the ueld field. Bits 0-2 of the ueld field are used to represent each layer of each UE, and bits 3-14 are used to represent each UE. This configuration allows bits 0-2 (3 bits) to represent 8 layers per UE and bits 3-14 (12 bits) to represent 2,048 UEs. In another example (not shown in the figure), bits 0-1 of ueld can represent each layer of each UE, and bits 2-14 of ueld can represent each UE. This allows 4,096 UEs and 4 layers per UE to be represented. The number of bits in each part can be predefined in the O-RU or configured by M-plane. For example, the O-DU can configure which bits are used to represent each UE and which bits are used to represent each layer of each UE.

[0115] Figure 16 illustrates another example for configuring the UE identification field (ueld) in accordance with some embodiments. In this example, the first part of the ueld field (the part representing each UE) comprises a least significant bit (LSB) of the ueld field. Bits 12-14 of ueld represent each layer of each UE, and bits 0-11 represent each UE. In someembodiments, the process is based on an identification field which is part of one or more messages communicated via a fronthaul interface. The one or more messages may contain measurement information or reference signal information such as Demodulation Reference Signal (DMRS) configuration.

[0116] In the examples shown in Figures 15 and 16, the O-RU can read the corresponding bits to determine which layers belong to which UE and perform operations per UE, such as calculating measurements per UE using the information from all layers of each UE. When the O-RU transmits the measurement with the ueld or the UE part of the ueld in the C-plane messages, the O-DU can identify which UE the measurement reports refer to.

[0117] In another embodiment, instead of redefining the ueld field, a new field is added in C-plane messaging. The new field has one or more entries, with the number of entries corresponding to the number of uelds used for each PRB range conveyed by each C-plane message. This corresponds to the number of layers scheduled for all layers of a single user when SU-MIMO (single-user MIMO) is used, or for all layers of a multi-user group when MU- MIMO (multi-user MIMO) is used. In some cases, the C-plane message may refer to only one ueld, such as referring to one layer out of multiple layers in SU-MIMO or MU-MIMO. In this scenario, the number of entries is one. Multiple C-plane messages are needed to support multiple layers. Each entry in the new field represents an index of the UE to which the layer, represented by a ueld in the same message, belongs. The number of bits per entry can be determined by the maximum number of UEs that MU-MIMO can support. For example, if MU-MIMO can support a maximum of eight layers, a minimum of three bits per entry is needed. Additional bits can be reserved for the future expansion to support more layers.

[0118] Figure 17 illustrates an example for configuring a new field in C-plane messaging with four entries in accordance with some embodiments. In this example, the four entries (Entries 1-4) correspond to four uelds (i.e., ueld #l-#4). Four layers are scheduled for a PRB range referenced by the four uelds (ueld #l-#4). The first two layers (ueld #l-#2) belong to the first UE, and the second two layers (ueld #3-#4) belong to the second UE. The first UE is represented by UE index = 0 and the second UE is represented by UE index = 1. This new field can be added in a new Section Extension and or a new Section Type to be defined in O-RAN WG4 CUS specification.

[0119] Optionally, an additional new field representing the number of UEs can be added before the UE index field. This can help the O-RU to know how many UEs are expected before parsing the UE index field.

[0120] In the example shown in Figure 17, the O-RU can read the new UE index field to determine which layers belong to which UE and then perform the operations per UE, such as calculating measurements per UE using the information from all layers for each UE. When the O-RU transmits the measurement with the new UE index field in C-plane messages to the O- DU, the O-DU can identify which UE the measurement reports refer to.

[0121] Figure 18 illustrates a flowchart showing method 1800 for communication performed by a network node in accordance with some embodiments. In this disclosure, a network node refers to any of the following devices: a device comprising an RU or an O-RU, a device comprising a DU or an O-DU, or a device comprising both an RU and a DU or both an O-RU and an O-DU. In block 1810 of method 1800, the network node configures a first portion of bits from an identification field to represent one or more UEs. The identification field comprises multiple bits. In some embodiments, the identification field is part of reference signal information or measurement information communicated via a fronthaul interface. In some embodiments, the configuration may be done via fronthaul Management Plane (M-Plane) protocol.

[0122] In block 1820 of method 1800, the network node configures a second portion of bits from remainder of the identification field to represent one or more user layers associated with the one or more UEs. In some embodiments, the configuration may be done via fronthaul M-Plane protocol.

[0123] In block 1830 of method 1800, the network node sends the identification field comprising the first portion of bits and the second portion of bits via a fronthaul interface protocol. The message can be a Control Plane (C-Plane) message or a User Plane (U-Plane) message.

[0124] Figure 19 illustrates a flowchart showing method 1900 for communication via a fronthaul interface protocol performed by a network node in accordance with some embodiments. The fronthaul interface protocol comprises a first field. In block 1910 of method 1900, the network node configures the first field to include a number of entries corresponding to a total number of one or more user layers. Each entry corresponds to a user layer of the one or more user layers. In some embodiments, the first field is configured in C-Plane messages.

[0125] In block 1920 of method 1900, the network node configures each entry to represent an index of a UE in the one or more UEs, the UE being associated with the user layer to which the entry corresponds.

[0126] In block 1930 of method 1900, the network node sends the first field via the fronthaul interface protocol.

[0127] Although the computing devices described herein (e.g., UEs, network nodes, hosts) 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.

[0128] 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 the described 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 network node, the method comprising: configuring a first portion of bits from an identification field to represent one or more user equipment (UEs), the identification field comprising multiple bits; configuring a second portion of bits from remainder of the identification field to represent one or more user layers associated with the one or more UEs; and sending the identification field comprising the first portion of bits and the second portion of bits via a fronthaul interface protocol.

2. The method of claim 1 , wherein the identification field is part of one or more messages communicated via a fronthaul interface, wherein the one or more messages contain reference signal information or measurement information.

3. The method of any of claims 1-2, wherein the first portion of bits comprises a least significant bit of the identification field.

4. The method of any of claims 1-2, wherein the first portion of bits comprises a most significant bit of the identification field.

5. The method of any of claims 1-4, wherein the first portion of bits and / or the second portion of bits are predefined in an Open Radio Access Network (O-RAN) Radio Unit (O-RU) of the network node or an O-RAN Distributed Unit (O-DU) of the network node.

6. The method of any of claims 1-5, wherein the first portion of bits and / or the second portion of bits are configured by a management plane (M-Plane) of the network node.

7. The method of any of claims 1-6, wherein the identification field or the first portion of bits is transmitted in control plane (C-Plane) messages.

8. The method of any of claims 1-7, wherein the network node is one of: a device comprising a Radio Unit (RU) or an Open Radio Access Network (O-RAN) Radio Unit (O-RU),a device comprising a Distributed Unit (DU) or an O-RAN Distributed Unit (O-DU), or a device comprising both an RU and a DU or both an O-RU and an O-DU.

9. A method performed by a network node for communicating information of one or more user equipment (UEs) via a fronthaul interface protocol, the fronthaul interface protocol comprising a first field, the method comprising: configuring the first field to include a number of entries corresponding to a total number of one or more user layers, wherein each entry corresponds to a user layer of the one or more user layers; for each entry, configuring the entry to represent an index of a UE in the one or more UEs, the UE being associated with the user layer to which the entry corresponds; and sending the first field via the fronthaul interface protocol.

10. The method of claim 9, wherein the first field is configured in control plane (C-Plane) messages.

11. The method of any of claims 9-10, where in the number of entries of the first field is equal to a number of ueld fields used for each physical resource block (PRB) range conveyed by each C-plane message.

12. The method of any of claims 9-11, further comprising: configuring a minimum number of bits for each entry of the first field, wherein the minimum number of bits for each entry of the first field depends on a maximum number of UEs that the network node can support.

13. The method of any of claims 9-12, wherein the fronthaul interface protocol further comprises a second field, the method further comprising: configuring the second field to represent a total number of the one or more UEs; and sending the second field via the fronthaul interface protocol.

14. The method of any of claims 9-13, wherein the network node is one of: a device comprising a Radio Unit (RU) or an Open Radio Access Network (O-RAN) Radio Unit (O-RU), a device comprising a Distributed Unit (DU) or an O-RAN Distributed Unit (O-DU),or a device comprising both an RU and a DU or both an O-RU and an O-DU.

15. A network node for enabling the network node to communicate information of one or more user equipment (UEs) via a fronthaul interface, the network node comprising: processing circuitry configured to perform any of the steps of any of the claims 1-14; and power supply circuitry configured to supply power to the processing circuitry.

16. The network node of claim 15, wherein the network node is one of: a device comprising a Radio Unit (RU) or an Open Radio Access Network (O-RAN) Radio Unit (O-RU), a device comprising a Distributed Unit (DU) or an O-RAN Distributed Unit (O-DU), or a device comprising both an RU and a DU or both an O-RU and an O-DU.

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