Signaling for Hybrid Beamforming in Open RAN

Abstract

The present disclosure relates to a 5G or 6G communication system that supports higher data transmission rates than 4G communication systems such as LTE (Long Term Evolution). For an Open Radio Access Network (O-RAN) system, the supported hybrid beamforming settings are indicated based on the number of analog ports, the number of digital ports, the number of analog ports per transceiver, and the supported codebook. The hybrid beamforming settings to be used include control bit vectors for phase shifters, each control bit vector being mapped to a phase value, an in-phase (I) value, and an orthogonal phase (Q) value. The hybrid beamforming settings may include analog and digital beamforming parameters or Joint Phase-Time Array (JPTA) parameters applicable to a frequency band or subband.

Description

Technology Field

[0001] The present disclosure generally relates to wireless access network fronthaul. More specifically, the present disclosure relates to hybrid beamforming in an open-radio access network (O-RAN). Background Technology

[0002] Wireless communication is one of the most successful innovations in modern history. Recently, the number of wireless communication service subscribers has surpassed 5 billion and is rapidly increasing. As the penetration of mobile data devices—such as smartphones, tablets, laptops, netbooks, e-book readers, and mobile devices—expands, the demand for wireless data traffic is also surging. To respond to this surge in mobile data traffic and support new applications and deployments, improving wireless interface efficiency and coverage is of paramount importance.

[0003] To meet the demand for wireless data traffic that has increased since the establishment of the 4th generation (4G) communication system and to support various vertical applications, the 5th generation (5G) communication system has been developed and is currently being built, and the 6th generation (6G) communication system is also being developed.

[0004] 5G communication systems may be implemented to include high frequency bands (millimeter wave or "mmWave" bands), such as 28 GHz (giga-Heriz) or 60 GHz bands, or generally bands above 6 GHz, to achieve higher data transmission speeds, or to include low frequency bands below 6 GHz to support strong coverage and mobility. Various aspects of the present disclosure may be applicable to the deployment of 5G communication systems, 6G or later versions of systems using terahertz (tHz) bands. In 5G communication systems, beamforming (BF), multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies are discussed to reduce propagation loss and increase transmission distance.

[0005] In addition, in 5G communication systems, development is underway to improve system networks based on advanced small cells, cloud radio access networks (RAN), ultra-high density networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP) communication, and receiver interference cancellation.

[0006] In 5G systems, advanced coding modulation (ACM) methods such as FQAM, which combines hybrid frequency shift key (FSK) and quadrature amplitude modulation (QAM), and sliding window superposition coding (SWSC) have been developed, while advanced access technologies such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) have been developed.

[0007] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th-generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th-generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are referred to as "Beyond 5G" systems.

[0008] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps, and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0009] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., the 95 GHz to 3 terahertz (3 THz) band). In the terahertz band, due to more severe path loss and atmospheric absorption compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technology capable of guaranteeing signal reach, or coverage, is expected to increase. As key technologies to ensure coverage, radio frequency (RF) devices, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multi-antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.

[0010] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (high-altitude platform stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (artificial intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0011] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances. The problem to be solved

[0012] The present disclosure provides instructions for supported hybrid beamforming settings based on the number of analog ports, the number of digital ports, the number of analog ports per transceiver, and the supported codebook for an Open Radio Access Network (O-RAN) system. The hybrid beamforming settings to be used include control bit vectors for phase shifters, each control bit vector being mapped to a phase value, an in-phase (I) value, and a quadrature (Q) value. The hybrid beamforming settings may include analog and digital beamforming parameters or joint phase-time array (JPTA) parameters applicable to a frequency band or subband. means of solving the problem

[0013] In a first embodiment, a method for operating a distributed unit (DU) includes receiving first information indicating a supported hybrid beamforming (BF) setting from a radio unit (RU), wherein the first information includes the number of analog ports, the number of digital ports, the number of analog ports per transceiver (TRX), and a supported codebook. Additionally, the method includes determining whether to downselect a supported codebook based on the first information. Furthermore, the method includes generating a hybrid BF setting and transmitting it to the RU. The hybrid BF setting includes a control bit vector for a phase shifter, wherein the control bit vector is mapped to a phase value, an in-phase (I) value, and an orthogonal phase (Q) value.

[0014] In a second embodiment, a distribution unit (DU) includes a transceiver configured to receive first information indicating a supported hybrid beamforming (BF) setting from a radio unit (RU), wherein the first information includes the number of analog ports, the number of digital ports, the number of analog ports per transceiver (TRX), and a supported codebook. The DU unit also includes a controller configured to determine whether to downselect the supported codebook based on the first information. The controller is further configured to generate a hybrid BF setting. The transceiver is configured to transmit the hybrid BF setting to the RU, wherein the hybrid BF setting includes a control bit vector for a phase shifter. The control bit vector is mapped to a phase value, an in-phase (I) value, and an orthogonal phase (Q) value.

[0015] In a third embodiment, the radio device (RU) includes a controller configured to control beamforming. Additionally, the RU device includes a transceiver configured to receive first information indicating a hybrid beamforming (BF) setting supported by a distributed unit (DU), wherein the first information includes the number of analog ports, the number of digital ports, the number of analog ports per transceiver (TRX), and a supported codebook. Whether to downselect the supported codebook is determined by the DU, and the DU generates a hybrid BF setting based on the first information. The transceiver is configured to receive a hybrid BF setting from the DU, wherein the hybrid BF setting includes a control bit vector for a phase shifter. The control bit vector is mapped to a phase value, an in-phase (I) value, and an orthogonal phase (Q) value.

[0016] A person skilled in the art will be able to easily identify other technical features from the following drawings, description, and claims.

[0017] Before beginning the detailed description below, it may be beneficial to provide definitions of specific words and phrases used throughout this patent document. The term "couple" and its derivatives refer to direct or indirect communication between two or more elements and are used regardless of whether the elements are in physical contact with each other. The terms "transmit," "receive," and "communicate," and their derivatives, encompass both direct and indirect communication. The terms "include" and "comprise," and their derivatives, mean inclusion without limitation. The term "or" is inclusive and means "and / or." The term "associated with" and its derivatives mean "include," "be included within," "interconnect with," "contain," "be included within," "connect to or with," "couple to or with," "be comminicable with," "cooperative with," "interleave," "juxtapose," "be proximate to," "be bound to or with," "have," "have a property of," "have a relationship to or with," etc. The term "controller" means any device, system, or part thereof that controls at least one operation. Such controllers may be implemented in hardware or as a combination of hardware and software and / or firmware.Functions associated with a specific controller may be centralized or distributed locally or remotely. The phrase "at least one of" used with a list of items implies that one or more of the listed items may be used in different combinations, and that only one item from the list may be required. For example, "at least one of A, B, and C" includes one of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0018] Additionally, the various functions described below may be implemented or supported by one or more computer programs, each program set in computer-readable program code and implemented on a computer-readable medium. The terms “application” and “program” refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or parts thereof that are adapted to be implemented in appropriate computer-readable program code. The phrase “computer-readable program code” includes all types of computer code, including source code, object code, and executable code. The phrase “computer-readable medium” includes all types of media accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drives (HDD), compact discs (CD), digital video discs (DVD), or any other type of memory. “Non-transitory” computer-readable media exclude wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transient computer-readable media include media capable of permanently storing data and media that can be overwritten later after storing data, such as rewritable optical discs or erasable memory devices.

[0019] Definitions for other specific words and phrases are provided throughout this patent document. Those skilled in the art should understand that, in most cases, these definitions apply to the prior and future use of the defined words and phrases. Effects of the invention

[0020] According to one embodiment of the present disclosure, the DU may transmit a control bit vector for the phase shifter of the RU instead of the in-phase (I) value and the quadrature phase (Q) value.

[0021] According to one embodiment of the present disclosure, the on / off function of the beamforming weight and beam identifier (ID) of analog / digital beamforming may be supported to minimize redundancy of control messages transmitted between the DU and the RU.

[0022] According to one example of the present disclosure, signaling overhead between the DU and the RU is reduced by providing a Joint Phase-Time Array (JPTA) specific fronthaul payload. Brief explanation of the drawing

[0023] To more fully understand the content of the present disclosure and its advantages, refer to the following description together with the accompanying drawings, wherein the same reference numerals denote the same parts. FIG. 1 illustrates an example of a wireless network (100) in which control information transmission through a hybrid beamforming for an open wireless access network (O-RAN) fronthaul or a joint phase-time array (JPTA) O-RAN fronthaul can be implemented according to an embodiment of the present disclosure. FIG. 2A illustrates an example of a wireless transmission path that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. FIG. 2B illustrates an example of a wireless receiving path that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. FIG. 3A illustrates an example of a UE that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. FIG. 3B illustrates an example of a gNB (102) that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. FIG. 4 illustrates an example of a beamforming architecture that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. Figure 4A illustrates the gNB JPTA architecture. Figure 4B illustrates the 2D beam pattern for the JPTA discrete-angle beam. FIG. 5 illustrates an example of an O-RAN architecture that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure. FIG. 6 illustrates an example of a single-layer hybrid beamforming architecture that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 6A illustrates an example of a single-layer hybrid beamforming architecture that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 7 illustrates an example of a multi-layer hybrid beamforming architecture that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 8 illustrates an example of hybrid beamforming used in connection with an O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 9 illustrates an example of a hybrid weighted dynamic beamforming setup that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 10 illustrates an example of a hybrid CSI-based beamforming setup that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 11 illustrates an example of mapping from a hybrid beam ID to an analog beam group ID and a digital beam ID according to an embodiment of the present disclosure. FIG. 12 illustrates an alternative example of hybrid beamforming used in connection with an O-RAN fronthaul according to an embodiment of the present disclosure. FIG. 13 illustrates an alternative example of an analog beam group ID and a digital beam ID in a hybrid beam ID according to an embodiment of the present disclosure. FIG. 14 illustrates an example of a C-plane hybrid beamforming setup having digital beamforming weights according to an embodiment of the present disclosure. FIG. 15 illustrates an example of a C-plane hybrid beamforming setup having analog and digital beamforming weights according to an embodiment of the present disclosure. FIG. 16 illustrates an example of a C-plane hybrid beamforming setup having analog and digital beamforming weights according to an embodiment of the present disclosure. FIG. 17 illustrates an example of a fronthole processing step used in connection with an O-RAN fronthole for JPTA according to an embodiment of the present disclosure. FIG. 18 illustrates a schematic flowchart of a hybrid beamforming setup process according to an embodiment of the present disclosure. Specific details for implementing the invention

[0024] The various embodiments used to illustrate the principles of the present disclosure and the FIGS. 1 through 18 described below are merely illustrative and should not be construed as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any type of device or system appropriately configured.

[0025] The following references are included by reference in this document.

[0026] [1] O-RAN Working Group 4 (Open Fronthaul Interfaces WG), "Control, User and Synchronization Plane Specification", O-RAN.WG4.CUS.0-R003-v13.00.

[0027] [2] I. Jain, et al., "Toward Flexible Frequency-Dependent mmWave Multi-Beamforming" International Workshop on Mobile Computing Systems and Applications (HotMobile '23), 2023, doi:10.1145 / 3572864.3581579.

[0028] [3] VV Ratnam et al., "Joint Phase-Time Arrays: A Paradigm for Frequency-Dependent Analog Beamforming in 6G", IEEE Access, vol. 10, pp. 73364-73377, 2022, doi: 10.1109 / ACCESS.2022.3190418.

[0029] [4] V. Boljanovic et al., "Fast Beam Training with True-Time-Delay Array in Broadband Millimeter-Wave Systems", IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 68, no. 4, pp. 1727-1739, April 2021, doi: 10.1109 / TCSI.2021.3054428.

[0030] [5] A. Alammouri et al., "Extending Uplink Coverage of mmWave and Terahertz Systems via Co-phase-time Arrays", IEEE Access, vol. 10, pp. 88872-88884, 2022, doi: 10.1109 / ACCESS.2022.3200334.

[0031] Open Radio Access Network (O-RAN) is a standard that defines protocols between Distributed Units (DU) and Radio Units (RU). O-RAN Partition Option 7-2x Category B is used for Massive Multiple Input Multiple Output (MIMO) products, where the signal of the compressed data stream is transmitted through the fronthaul rather than through all antenna port signals.

[0032] Joint Phase-Time Arrays (JPTA), a new beamforming and frequency multiplexing radio frequency front-end architecture, is attracting attention as a promising technology for 5G and 6G. As shown in Fig. 4A, a JPTA network consists of phase shifters and delay devices, enabling transceivers to perform frequency-dependent beamforming so that multiple UEs (User Devices) located at different spatial locations can be serviced from different sets of resource blocks (PRBs). This allows UEs to experience relatively high beam gain and low inter-UE interference. Fig. 4B shows an example of a JPTA beam pattern, where the JPTA beam is designed to service UEs located at angles of -30°, -15°, 15°, and 30°. Since UEs at different angles can obtain maximum beam gain from different frequency bands or sets of RBs, the base station can multiplex data for all users without causing inter-user interference or sacrificing the beam gain of some UEs. Various algorithms have been proposed to design the JPTA beam (a set of phases and delays required to set up a JPTA radio frequency network) as in [2, 3], and potential performance improvements have also been studied in [4, 5].

[0033] FIGS. 1-2 and FIGS. 3A-3B illustrate various embodiments implemented in a wireless communication system according to an embodiment of the present disclosure. The description of FIGS. 1-2 and FIGS. 3A-3B does not imply any physical or structural limitations on the implementation of different embodiments. Various embodiments of the present disclosure may be implemented in any appropriately configured communication system.

[0034] FIG. 1 illustrates an example of a wireless network (100) in which control information transmission through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA can be implemented according to an embodiment of the present disclosure.

[0035] The embodiment of the wireless network (100) illustrated in FIG. 1 is for illustrative purposes only. Other embodiments of the wireless network (100) may be used without departing from the scope of the present disclosure.

[0036] As illustrated in FIG. 1, the wireless network (100) includes gNodeB (gNB) (101), gNB (102), and gNB (103). The gNB (101) communicates with the gNB (102) and gNB (103). The gNB (101) also communicates with one or more Internet Protocol (IP) networks (130), such as the Internet, a proprietary IP network, or other data networks.

[0037] Depending on the network type, the term 'gNB' may refer to any component (or set of components) configured to provide wireless network access to a remote terminal, such as a base station, a radio base station, a transmission point (TP), a transmission and reception point (TRP), a ground gateway, an aircraft-mounted gNB, a satellite system, a mobile base station, a macrocell, a femtocell, a WiFi access point (AP), etc. Additionally, depending on the network type, other well-known terms such as 'mobile station,' 'subscriber station,' 'remote terminal,' 'wireless terminal,' or 'user device' may be used instead of 'user device' or 'UE.' For convenience, the terms 'user device' and 'UE' are used in this patent document to refer to remote wireless equipment that wirelessly accesses the gNB, and the UE may be a mobile device (e.g., a mobile phone or a smartphone) or a device generally considered to be a fixed device (e.g., a desktop computer or a vending machine).

[0038] The above gNB (102) provides wireless broadband access to the network (130) to a first plurality of user devices (UEs) located within the coverage area (120) of the gNB (102). The first plurality of UEs include a UE (111) located in a small business (SB), a UE (112) located in a large business (E), a UE (113) located in a WiFi hotspot (HS), a UE (114) located in a first residential area (R), a UE (115) located in a second residential area (R), and a UE (116) which is a mobile device (M) such as a mobile phone, a wireless laptop, a wireless PDA, etc. The above gNB (103) provides wireless broadband access to the network (130) to a second plurality of UEs (user devices) located within the coverage area (125) of the gNB (103). The second plurality of UEs includes a UE (115) and a UE (116). In some embodiments, one or more gNBs (101-103) can communicate with each other and with UEs (111-116) using 5G, LTE (Long-Term Evolution), LTE-A, WiMAX, or other advanced wireless communication technologies.

[0039] The dotted lines indicate the approximate range of the coverage areas (120 and 125) and are shown as circles for illustrative and illustrative purposes. It should be clearly understood that the coverage areas associated with the gNB (e.g., coverage areas (120 and 125)) may have different shapes, including irregular shapes, depending on the configuration of the gNB and changes in the wireless environment related to natural and artificial obstacles.

[0040] As described in more detail below, one or more of gNB (101), gNB (102) and gNB (103) include circuitry, programming, or a combination thereof to support signaling transmission for hybrid beamforming between DU and RU in an O-RAN network.

[0041] FIG. 1 illustrates one example of a wireless network (100), but FIG. 1 is subject to various modifications. For example, the wireless network (100) may include any number of gNBs and any number of UEs in an appropriate configuration. Additionally, the gNB (101) may communicate directly with any number of UEs to provide the UEs with wireless broadband access to the network (130). Likewise, each gNB (102-103) may also communicate directly with the network (130) to provide the UEs with direct wireless broadband access to the network (130). Furthermore, the gNBs (101, 102 and / or 103) may provide access to other external networks, such as an external telephone network or other types of data networks.

[0042] FIGS. 2A and 2B illustrate examples of wireless transceiver paths that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to embodiments of the present disclosure.

[0043] In the following description, the transmission path (200) may be described as being implemented in a gNB (e.g., gNB (102)) and the reception path (250) as being implemented in a UE (e.g., UE (116)). However, it should be understood that the reception path (250) may be implemented in a gNB and the transmission path (200) may be implemented in a UE. In some embodiments, the reception path (250) is configured to support the codebook design and structure of a system having a 2D antenna array as described in the embodiments of the present disclosure.

[0044] The transmission path (200) includes a channel coding and modulation block (205), a serial-to-parallel (S-to-P) block (210), an inverse Fast Fourier Transform (IFFT) block of size N (215), a parallel-to-serial (P-to-S) block (220), a cyclic preposition addition block (225), and an up converter (UC) (230). The reception path (250) includes a down converter (DC) (255), a cyclic preposition removal block (260), a serial-to-parallel (S-to-P) block (265), an inverse Fast Fourier Transform (FFT) block of size N (270), a parallel-to-serial (P-to-S) block (275), and a channel decoding and demodulation block (280).

[0045] In the transmission path (200), the channel coding and modulation block (205) receives a set of information bits, applies coding (e.g., low-density parity check; LDPC coding), and then modulates the input bits (e.g., quadrature phase shift keying (QPSK) or QAM) to generate a frequency domain modulated symbol sequence. The serial-to-parallel conversion block (210) converts the serially modulated symbols into parallel data (e.g., demultiplexing) to generate N parallel symbol streams, where N is the size of the inverse fast Fourier transform (IFFT) / fast Fourier transform (FFT) used in the gNB (102) and UE (116). The size N IFFT block (215) performs an IFFT operation on the N parallel symbol streams to generate a time domain output signal. The parallel-to-serial conversion block (220) converts (e.g., multiplexes) the parallel time-domain symbols output from the size N IFFT block (215) to generate a serial time-domain signal. The cyclic preposition addition block (225) inserts a cyclic preposition into the time-domain signal. The up-converter (230) modulates (e.g., up-converts) the output of the cyclic preposition addition block (225) to an RF frequency for transmission over a wireless channel. The signal may be filtered in the baseband before being converted to the RF frequency.

[0046] The RF signal transmitted from the gNB (102) reaches the UE (116) via a wireless channel, and the UE (116) operates in the reverse order of the operation at the gNB (102). In the receiving path (250), the downconverter (255) downconverts the received signal to a baseband frequency, and the cyclic preposition removal block (260) removes cyclic prepositions to generate a serial time domain baseband signal. The serial-to-parallel conversion block (265) converts the time domain baseband signal into a parallel time domain signal. The size N FFT block (270) performs an FFT algorithm to generate N parallel frequency domain signals. The parallel-to-serial conversion block (275) converts the parallel frequency domain signals into a modulated data symbol sequence. The channel decoding and demodulation block (280) demodulates and decodes the modulated symbols to recover the original input data stream.

[0047] Each gNB (101-103) can implement a transmission path (200) similar to downlink transmission to a UE (111-116) and a reception path (250) similar to uplink reception from a UE (111-116). Likewise, each UE (111-116) can implement a transmission path (200) for uplink transmission to a gNB (101-103) and a reception path (250) for downlink reception from a gNB (101-103).

[0048] Each component of FIGS. 2A and 2B can be implemented in hardware alone or in combination with hardware and software / firmware. For example, at least some of the components of FIGS. 2A and 2B may be implemented in software, and other components may be implemented in configurable hardware or a combination of software and configurable hardware. For example, the FFT block (270) and the IFFT block (215) may be implemented as configurable software algorithms, and the value of size N may change depending on the implementation method.

[0049] Additionally, although the use of FFT and IFFT has been described in this specification, this is merely illustrative and should not be construed as limiting the scope of this specification. Other types of transforms, such as the Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions, may also be used. It should be understood that the value of the variable N can be any integer (e.g., 1, 2, 3, 4, etc.) for the DFT and IDFT functions, and the value of the variable N can be any integer that is a power of 2 (e.g., 1, 2, 4, 8, 16, etc.) for the FFT and IFFT functions.

[0050] FIGS. 2A and 2B illustrate examples of wireless transmission and reception paths, but FIGS. 2A and 2B are subject to various modifications. For example, various components of FIGS. 2A and 2B can be combined, further subdivided, or omitted, and additional components can be added according to specific requirements. Additionally, FIGS. 2A and 2B are intended to illustrate examples of various transmission and reception path types that can be used in wireless networks. Other suitable architectures may also be used to support wireless communication in wireless networks.

[0051] FIG. 3A illustrates an example of a UE that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure.

[0052] The embodiment of the UE (116) illustrated in FIG. 3A is for illustrative purposes only, and the UE (111-115) of FIG. 1 may have the same or similar configuration. However, the UE may have a wide variety of configurations, and FIG. 3A is not intended to limit the scope of the disclosure to a specific UE implementation.

[0053] The above UE (116) includes an antenna (305), a radio frequency (RF) transceiver (310), a transmission (TX) processing circuit (315), a microphone (320), and a reception (RX) processing circuit (325). Additionally, the above UE (116) includes a speaker (330), a main processor (340), an input / output (I / O) interface (IF) (345), a keypad (350), a display (355), and a memory (360). The memory (360) includes a basic operating system (OS) program (361) and one or more application programs (362).

[0054] The RF transceiver (310) receives a received RF signal transmitted from the antenna (305) to the gNB of the wireless network (100). The RF transceiver (310) down-converts the received RF signal to generate an intermediate frequency (IF) or baseband signal. This IF or baseband signal is transmitted to a receiving processing circuit (325) to generate a baseband signal processed through filtering, decoding, and / or digitization. The receiving processing circuit (325) transmits the processed baseband signal to a speaker (330) (e.g., voice data) or a main processor (340) (e.g., web browsing data) to perform further processing.

[0055] The transmission (TX) processing circuit (315) receives analog or digital voice data from the microphone (320) or other transmission baseband data, such as web data, email, or interactive video game data, from the main processor (340). The transmission processing circuit (315) encodes, multiplexes, and / or digitizes the transmission baseband data to generate a processed baseband or intermediate frequency (IF) signal. The RF transceiver (310) receives the processed baseband or IF signal transmitted from the transmission processing circuit (315), upconverts this signal into an RF signal, and transmits it through the antenna (305).

[0056] The main processor (340) may include one or more processors or other processing units and controls the overall operation of the UE (116) by executing a basic OS program (361) stored in memory (360). For example, the main processor (340) may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver (310), the RX processing circuit (325), and the TX processing circuit (315) according to well-known principles. In some embodiments, the main processor (340) includes at least one microprocessor or microcontroller.

[0057] The main processor (340) may also execute other processes and programs residing in memory (360). The main processor (340) may move data to or from memory (360) as needed by the running processes. In some embodiments, the main processor (340) is configured to execute an application (362) according to an OS program (361) or in response to a signal received from a gNB or an operator. The main processor (340) is also connected to an input / output interface (345) to allow the UE (116) to connect to other devices, such as notebook computers and portable computers. The input / output interface (345) is a communication path between these accessories and the main controller (340).

[0058] The main processor (340) is also connected to a keypad (350) and a display device (355). A user of the UE (116) can input data into the UE (116) using the keypad (350). The display (355) may be a liquid crystal display (LCD) or another display capable of displaying text and / or at least limited graphics provided in places such as websites. The memory (360) is connected to the main processor (340). Part of the memory (360) may include RAM (random access memory), and another part may include flash memory or ROM (read-only memory).

[0059] FIG. 3B illustrates an example of a gNB (102) that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure.

[0060] The embodiment of the gNB (102) shown in FIG. 3B is for illustrative purposes only, and other gNBs of FIG. 1 may have the same or similar configurations. However, gNBs exist in a wide variety of configurations, and FIG. 3B does not limit the scope of the present disclosure to a specific gNB implementation. It should be noted that gNB (101) and gNB (103) may include structures identical or similar to gNB (102).

[0061] As illustrated in FIG. 3B, the gNB (102) includes a plurality of antennas (370a-370n), a plurality of RF transceivers (372a-372n), a transmit (TX) processing circuit (374), and a receive (RX) processing circuit (376). In a specific embodiment, one or more of the plurality of antennas (370a-370n) may include a 2D antenna array. The gNB (102) also includes a controller / processor (378), memory (380), and a backhaul or network interface (382).

[0062] The RF transceivers (372a-372n) receive a received RF signal, such as a signal transmitted from a UE or another gNB, from an antenna (370a-370n). The RF transceivers (372a-372n) down-convert the received RF signal to generate an IF or baseband signal. The generated IF or baseband signal is transmitted to a receive processing circuit (376), which generates a processed baseband signal through filtering, decoding, and / or digitization. The receive processing circuit (376) transmits the processed baseband signal to a controller / processor (378) for further processing.

[0063] The transmission (TX) processing circuit (374) receives analog or digital data (e.g., voice data, web data, email, or interactive video game data) from the controller / processor (378). The transmission processing circuit (374) encodes, multiplexes, and / or digitizes the output baseband data to generate a processed baseband or intermediate frequency (IF) signal. The RF transceivers (372a-372n) receive the processed baseband or intermediate frequency (IF) signal output from the transmission processing circuit (374), upconvert this signal into an RF signal, and transmit it through the antennas (370a-370n).

[0064] The controller / processor (378) may include one or more processors or other processing units that control the overall operation of the gNB (102). For example, the controller / processor (378) may control the reception of forward channel signals and the transmission of reverse channel signals by RF transceivers (372a-372n), an RX processing circuit (376), and a TX processing circuit (374) according to well-known principles. The controller / processor (378) may also support additional functions, such as advanced wireless communication functions. For example, the controller / processor (378) may perform a Blind Interference Detect (BIS) process, such as that performed in a BIS algorithm, and decode the received signal after subtracting the interference signal. The controller / processor (378) may support various other functions in the gNB (102). In some embodiments, the controller / processor (378) includes one or more microprocessors or microcontrollers.

[0065] The controller / processor (378) can execute programs and other processes residing in memory (380), such as a basic operating system. Additionally, as described in the embodiments of this disclosure, the controller / processor (378) can support signaling processing for hybrid beamforming between the DU and RU within the gNB (102). In some embodiments, the controller / processor (378) supports communication between entities such as Web RTC. The controller / processor (378) can move data to or from memory (380) according to the requirements of the running process.

[0066] The controller / processor (378) is also connected to a backhaul or network interface (382). Through the backhaul or network interface (382), the gNB (102) can communicate with other devices or systems via a backhaul connection or a network. The interface (382) may support communication via a suitable wired or wireless connection. For example, if the gNB (102) is implemented as part of a cellular communication system (such as a system supporting 5G, LTE, or LTE-A), the interface (382) enables the gNB (102) to communicate with other gNBs via a wired or wireless backhaul connection. If the gNB (102) is implemented as an access point, the interface (382) enables the gNB (102) to communicate via a wired or wireless local area network (LAN) or a larger network (e.g., the Internet) via a wired or wireless connection. The interface (382) may include a suitable structure that supports communication via a wired or wireless connection, such as an Ethernet or RF transceiver.

[0067] The memory (380) is connected to a controller / processor (378). Part of the memory (380) may include RAM, and another part may include flash memory or other types of ROM. In a specific embodiment, a plurality of instructions, such as a BIS algorithm, are stored in the memory. These plurality of instructions are configured so that the controller / processor (378) performs BIS processing and decodes a received signal after removing one or more interference signals identified by the BIS algorithm.

[0068] As described in more detail below, the transmission and reception paths of the gNB (102) (implemented using RF transceivers (372a-372n), TX processing circuit (374) and / or RX processing circuit (376)) support communication through the aggregation of frequency division duplex (FDD) cells and time division duplex (TDD) cells.

[0069] FIG. 3B shows one example of a gNB (102), but various modifications are possible in FIG. 3B. For example, the gNB (102) may include as many of each component shown in FIG. 3B as desired. As a specific example, the access point may include multiple interfaces (382), and the controller / processor (378) may support a routing function that routes data between different network addresses. As another specific example, FIG. 3B shows one TX processing circuit (374) and one RX processing circuit (376) each, but the gNB (102) may include multiple circuits each (e.g., one per RF transceiver).

[0070] Rel.13 LTE supports up to 16 Channel State Information Reference Signal (CSI-RS) antenna ports, allowing a gNB to be equipped with multiple antenna elements (e.g., 64 or 128). In this case, multiple antenna elements are mapped to a single CSI-RS port. Additionally, Rel.14 LTE is expected to support up to 32 CSI-RS ports. The maximum number of CSI-RS ports is also expected to remain nearly the same in next-generation cellular systems such as 5G.

[0071] FIG. 4 illustrates an example of a beamforming architecture that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure.

[0072] The embodiment of the beamforming architecture (400) illustrated in FIG. 4 is for illustrative purposes only. FIG. 4 is not intended to limit the scope of the present disclosure to a specific beamforming architecture implementation. It may be seen that the beamforming architecture (400) or a similar structure may be implemented in any one of the gNB (101), gNB (102), and / or gNB (103) of FIG. 1. Additionally, it may be seen that the beamforming architecture (400) or a similar structure may be implemented in any one of the RF transceivers (372a), RF transceivers (372b), and / or RF transceivers (372n) of FIG. 3B.

[0073] The beamforming architecture (400) receives an input signal (401) corresponding to a transmitted signal. The beamforming architecture (400) includes a digital beamforming circuit (402) and a plurality of analog beamforming circuits (403a-403n). The digital beamforming circuit (402) includes a baseband digital precoder (404) that receives the input signal (401) and outputs the signal to multiple circuit chains corresponding to the number of CSI-RS ports. Each circuit chain includes an IFFT block (405a-405n) and a parallel-to-serial conversion block (406a-406n). The circuit chain output within the digital beamforming circuit (402) is transmitted to the corresponding DAC (407a-407n), and the output of the DAC (407a-407n) is transmitted through the mixer (409a-409n) to each instance of the analog beamforming circuit (403a-403n). Each instance of the analog beamforming circuit (403a-403n) has a plurality of circuit chains including an analog phase shifter (410) and a power amplifier (PA) (411), which are connected in series with each other and are also connected to an antenna element array (412). Each instance of the analog beamforming circuit (403a-403n) transmits a signal using at least one of the plurality of beams (413a-413n).

[0074] In the case of the millimeter wave band, the number of antenna elements for a given form factor may be greater, but as illustrated by the beamforming architecture (400) in FIG. 4, the number of CSI-RS ports (corresponding to the number of digital precoding ports) tends to be limited due to hardware constraints (e.g., the feasibility of installing multiple analog-to-digital converters (ADCs) / digital-to-analog converters (DACs) at millimeter wave frequencies). In this case, one CSI-RS port is mapped to multiple antenna elements, and these elements can be controlled by an analog phase shifter (410) bank. Thus, one CSI-RS port can correspond to one sub-array that generates a narrow analog beam through analog beamforming (403a-403n). This analog beam can be configured to sweep a wider angular range (a range enclosed by beam (413a), beam (413n), etc.) by changing the phase shifter bank over a symbol, subframe, or slot (a subframe or slot may be a collection of symbols or include a transmission time interval (TTI)). The number of subarrays (equal to the number of RF chains) is the CSI-RS port The digital beamforming circuit (402) is equal to the number of. A linear combination is performed on the analog beam to further increase the precoding gain. The analog beam is broadband (and therefore lacks frequency selectivity), but digital precoding can be varied across frequency subbands or resource blocks.

[0075] FIG. 4A illustrates a gNB JPTA architecture (450) having one RF chain and a single phase shifter per antenna element, which can be used with a beamforming architecture (400). The RF chain (451) may include a digital beamforming circuit (402) and a DAC (407a-407n). The analog beamforming circuit includes a plurality (N) of adjustable delay devices (452a, 452b, ..., 452n) connected to a switching circuit (453). The output of the switching circuit (453) is passed to M adjustable phase shifters (410a, 410b, ..., 410m) connected to a PA (411a, 411b, ..., 411m) and antenna elements (412a, 412b, ..., 412m), respectively.

[0076] Figure 4B illustrates the 2D beam pattern for the JPTA discrete angle beam. Here, angles {-30, -15, 15, 30} are associated with different subcarrier bundles that provide high beam gain.

[0077] FIG. 5 illustrates an example of an O-RAN architecture that can be used in connection with the transmission of control information through hybrid beamforming for O-RAN fronthaul or O-RAN fronthaul for JPTA according to an embodiment of the present disclosure.

[0078] The embodiment of the O-RAN architecture (500) illustrated in FIG. 5 is for illustrative purposes only. FIG. 5 does not limit the scope of the present disclosure to a specific O-RAN architecture implementation.

[0079] The above O-RAN architecture (500) includes a distributed unit (DU; 501) and a radio unit (RU; 502) connected to a control (C) plane (503) and a user (U) plane (504). Those skilled in the art will understand the uplink (UL) signal flow within the DU (501), within the RU (502), and across the DU (501) and RU (502) according to some embodiments of the existing O-RAN specification. For example, the O-RAN architecture (500) may be implemented in any one of the gNB (101), gNB (102), and / or gNB (103) of FIG. 1. For the sake of brevity and clarity, the entire structure and operation of the O-RAN system are not illustrated or described in this specification. Instead, only parts of the O-RAN system necessary for understanding this specification are illustrated and described.

[0080] For the UL in hybrid beamforming MIMO, the DU (501) generates a general UL spatial coupling weight (505) (spatial compression matrix). The UL spatial coupling weight (505) is generated per subband and per data stream. For example, the UL spatial coupling weight (505) may be a 16×256 complex matrix (where 16 corresponds to the number of data streams (or layers) and 256 corresponds to the number of transceivers of the RU (radio device)). The UL spatial coupling weight (505) is transmitted to the RU (502) via the C-plane (503) of the O-RAN protocol. Then, the RU (502) applies spatial compression to the 256 port received signals of each resource element by multiplying the UL spatial coupling weight (505) by the 256 port received signals in hybrid beamforming (506). Subsequently, these 16 data streams are compressed using compression (507), such as block floating (in-band and orthogonal (IQ)) compression, and transmitted to the DU (501) via the O-RAN U-plane (504). The DU (501) performs MIMO equalization (508) on the signal received from the RU (502) and then performs demodulation and decoding (509).

[0081] FIGS. 6 and 6A illustrate an example of a single-layer hybrid beamforming architecture that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure.

[0082] The embodiment of the hybrid beamforming architecture (600) illustrated in FIGS. 6 and 6A is for illustrative purposes only. FIGS. 6 and 6A are not intended to limit the scope of the present disclosure to a specific implementation of the hybrid beamforming architecture. Additionally, the hybrid beamforming architecture (600) described above It can be implemented for all layers corresponding to the CSI-RS port.

[0083] The hybrid beamforming architecture (600) of FIGS. 6 and FIGS. 6A includes a plurality of sub-arrays (601, 601b, ..., 601n) that implement analog (time domain) beamforming (602). An enlarged view of one of the sub-arrays (601n) of FIGS. 6 is shown in FIGS. 6A. The hybrid beamforming architecture (600) has a total of K analog ports (603), K phase shifters (604), and K' digital ports (605) across the sub-arrays (601a, 601b, ..., 601n). Thus, each sub-array (601a, 601b, ..., 601n) includes p'=K / K' of all analog ports (603) and all phase shifters (604). Phase value within each sub-array (601n) The index a Subarrays and indexes having b cast It is used in analog ports. The outputs (digital ports (605)) of the sub-arrays (601a, 601b, ..., 601n) are connected to K' transceivers (606) (TRX, not shown in the graph), and each transceiver provides one input to digital (frequency domain) beamforming (607). In the case of the single-layer hybrid beamforming architecture (600) of FIG. 6, weight groups One of them is applied to each input of digital (frequency domain) beamforming (607), where 0, ..., k '- 1 is the index of the transceiver (606) connected to each input.

[0084] In fact, the MIMO RU hybrid beamforming architecture (600) depicted in FIG. 6 performs hybrid beamforming in the uplink, which includes both analog spatial coupling and digital spatial coupling, and can be processed into a single layer at the output (608) after being connected from K analog ports (603) to K' transceivers (606).

[0085] The analog beamforming circuit (602) processes the received analog signal in the time domain. K analog ports (603) are coupled to the left of K' transceivers (606), as shown in FIG. 6. Each of the K analog ports (603) has a configurable phase shifter. The K analog ports are divided into K' sub-arrays (601a, 601b, ..., 601n). Within each sub-array (601n), p'=K / K' analog ports (603) are phase-shifted and coupled to a single digital port, i.e., the input of the corresponding transceiver (606). The phase shifter values ​​for the total K phase shifters (604) are correlated with each other within a specific time interval (e.g., symbol, slot, etc.). The digital beamforming circuit (607) processes the signal received from the K' transceivers (606) in the frequency domain.

[0086] In some embodiments, all K phase shifter values ​​are set for analog BF.

[0087] In some embodiments, the analog beam identifier (ID) is associated with each p' phase shifter value for the p' phase shifter (604) in the sub-array (601n). The mapping between the analog beam ID and the phase shifter value may be hardcoded in the RU or set by the DU.

[0088] In some embodiments, the analog beam group ID is associated with K' analog beam IDs or K phase shifter values. This mapping can be hardcoded in the RU or set by the DU. Analog beamforming is set by setting the analog beam group ID.

[0089] FIG. 7 illustrates an example of a multi-layer hybrid beamforming architecture that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure.

[0090] The embodiment of the hybrid beamforming architecture (700) illustrated in FIG. 7 is for illustrative purposes only. FIG. 7 does not limit the scope of the present disclosure to a specific implementation of the hybrid beamforming architecture.

[0091] The hybrid beamforming architecture (700) of FIG. 7 includes a plurality of sub-arrays (701a, 701b, ..., 701n) that collectively implement analog (time domain) beamforming (702). The hybrid beamforming architecture (700) has a total of K analog ports (703), K phase shifters (704), and K' digital ports (705) across the sub-arrays (701a, 701b, ..., 701n). Thus, each sub-array (701n) includes p' = K / K' of the total analog ports (703) and total phase shifters (704). Phase value within each sub-array (701n) is the index a Subarrays and indexes having b It is used for analog ports having. The outputs (digital ports (705)) of the sub-arrays (701a, 701b, ..., 701n) are connected to K' transceivers (706) (not shown in the graph), each transceiver providing one input to digital (frequency domain) beamforming (707a, ..., 707x). In the multi-layer hybrid beamforming architecture (700) of FIG. 7, weight groups One of them is applied to each input of digital (frequency domain) beamforming (707a, ..., 707x), where l silver L Dog layer It is one of the indices, and 0, ..., k '- 1 is the index of one of the transceivers (706) connected to each input. The single-layer digital beamforming architecture (600) shown in FIG. 6 includes a single instance of digital beamforming (607) to the right of K' transceivers (606). The weight ( ) combines the signals of K' transceivers (606) into a single layer at the output (608). Multiple (e.g., as shown in FIG. 7) L In the ) layer hybrid beamforming architecture (700), a similar group of K' transceivers (706) contributes to each layer. Each layer has K' digital beamforming weights ( It is generated by ) and transmitted as one of the outputs (708a, ..., 708x).

[0092] In some embodiments, K'* L Digital beamforming weights are set to configure digital beamforming.

[0093] In some embodiments, L doggy Digital beam IDs are set, and each digital beam ID is mapped to a specific digital beamforming weight group. These mappings can be hardcoded in the RU or set by the DU.

[0094] In some embodiments, digital beamforming is set per subband. The digital beamforming weights in each subband may differ from those in other subbands. As the subband width decreases, the level of segmentation and the signal interference noise ratio (SINR) are improved, and as the subband width increases, fronthaul traffic and computational efficiency are improved.

[0095] The total parameters that must be set in hybrid beamforming include K phase shifter values ​​for analog beamforming and K' weights per layer and subband for digital beamforming.

[0096] In the C-plane, control messages are defined as section types (STs) in the O-RAN Control, User, and Synchronization Plane (CUS Plane) specification. There are six predefined STs, and ST1, ST3, ST4, and ST5 are designed for uplink spatial coupling setups. For example, ST1 is for DL / UL radio channels requiring a time or frequency offset, ST3 is for channels requiring a time or frequency offset, and ST5 is for UE scheduling information. Generally, ST1, ST3, and ST5 include the frame, subframe, slot, symbol range, and Physical Resource Block (PRB) range to which spatial coupling will be applied. In addition to STs, section extensions (SEs) can be used to transmit additional information. For example, SE1, SE2, and SE11 are designed for transmitting beamforming weights, beamforming attributes, and flexible beamforming weights.

[0097] An example of hybrid beamforming configuration signaling according to O-RAN specifications is as follows.

[0098] 1. ST1 + SE1: Digital and analog beamforming settings are transmitted together in a single section description. The K' digital beamforming weights and K analog beamforming weights consist of in-phase and quadrature (I / Q) values. Each section description of ST1 and SE1 includes hybrid beamforming weights for one data layer and one subband.

[0099] 2. ST1 + SE11: Digital and analog beamforming settings are transmitted together in a single section description. K' digital beamforming weights and K analog beamforming weights are configured as I / Q values. Each section description of ST1 and SE1 includes hybrid beamforming weights for one data layer and multiple subbands.

[0100] 3. ST1 + SE1 and ST4: Digital and analog beamforming settings are transmitted separately in ST1+SE1 and ST4, respectively. K' digital beamforming weights are configured as I / Q values ​​per layer and per subband in ST1 + SE1. Analog beam group IDs, K' 15-bit analog beam IDs, and K analog beamforming weights are configured as I / Q values ​​and transmitted per slot in ST4.

[0101] 4. ST5+SE10+SE1: The User Device (UE) ID (ueId) is set via ST5+SE10, and the RU performs Channel State Information (CSI) Based Beamforming (CIBF) for digital beamforming. Analog beamforming settings are included in SE1 along with the KI / Q values ​​of the time interval phase shifter described in ST5.

[0102] However, the current O-RAN standard has the following problems.

[0103] 1. In all hybrid beamforming configurations of the O-RAN standard, the analog phase shifter configuration format is fixed to setting in-phase (I) and quadrature phase (Q) values. However, this limited format is not practical for phase shifter configurations that operate in a codebook-based manner.

[0104] 2. In all hybrid beamforming configurations of the O-RAN standard, the bit width of the analog beam ID is fixed at 15 bits according to the O-RAN standard. However, 15 bits are unnecessary in RU designs where the number of states is much less than 215.

[0105] 3. Existing O-RAN hybrid BF configuration methods have limitations. SE1 repeatedly transmits the same analog BF configuration as SE1 or SE11. This leads to excessive redundancy in large-scale MIMO environments, which can result in the transmission of more redundant information than is necessary.

[0106] The present disclosure solves the problems identified as follows.

[0107] DU transmits a control bit vector for the RU's phase shifter instead of the I / Q value.

[0108] The DU transmits an analog beam ID with reduced bit width instead of 15 bits.

[0109] The bit width of the control bit vector and beam ID is set through the management plane (M(management)-plane) from the RU to the DU.

[0110] A hybrid beamforming setup with reduced bit width can be implemented in the SE or by setting up analog beamforming in a separate ST.

[0111] To minimize message duplication, an on / off function for beamforming weights / beam IDs in analog / digital beamforming can be supported.

[0112] Compression of analog beamforming weights can be dynamically set in the C-plane separately from digital beamforming.

[0113] The mapping between the total beam ID, digital beam ID, and analog beam group ID can be established via the M-plane or C-plane. The digital or analog beam field (BF) setting can be derived from the RU.

[0114] According to one embodiment, the RU reports hybrid BF-related configurations and codebooks to the DU via the M-plane. Except where the codebooks already exist in the O-RAN specification, in some embodiments, the following additional codebooks are transmitted: 1) a codebook mapping analog phase shifter values ​​and control bit vectors, 2) a codebook mapping analog beam IDs and phase shifter values ​​per TRX, etc. These codebooks also include the bit widths of the control bit vectors and beam IDs. The bit widths are used directly in C-plane messages or are mentioned repeatedly for the convenience of the RU implementation.

[0115] FIG. 8 illustrates an example of hybrid beamforming used in connection with an O-RAN fronthaul according to an embodiment of the present disclosure.

[0116] The embodiment of the signaling (800) illustrated in FIG. 8 is for illustrative purposes only. FIG. 8 does not limit the scope of the present disclosure to a specific implementation of the signaling.

[0117] Figure 8 is an example showing DU and RU operations, and the steps in the figure describe UL spatial coupling weight setting and MIMO data reception as follows.

[0118] 1. Transmission of RU information regarding supported hybrid beamforming configurations / codebooks via the M-plane: The RU transmits supported hybrid beamforming configuration information to the DU using the M-plane. The configuration information includes the number of analog ports, the number of digital ports (transceivers), the number of analog ports per transceiver, and the codebook (e.g., digital beamforming weights, analog phase shifter control bit vectors, analog beam IDs, analog beam group IDs, etc.).

[0119] 2. For each codebook, the DU optionally performs downselection to reduce the codeword length. The DU optionally downselects from the codebooks provided by the RU in the previous step.

[0120] 3. Transmission of DU information regarding down-selected codebooks via M-plane: The DU optionally transmits information regarding down-selected codebooks via M-plane to the RU. The RU updates the codebooks accordingly.

[0121] 4. Create analog and digital beamforming settings for the DU's targeting resource element: The DU creates analog / digital beamforming weights or selects an analog / digital beam ID to represent the beamforming weights.

[0122] 5. Transmission of DU information regarding hybrid beamforming settings via C-plane: The DU transmits hybrid beamforming settings to the RU via C-plane messages. Both digital and analog beamforming settings are specified. The beam ID format and beamforming weight (BFW) values ​​are determined according to the hybrid beamforming settings.

[0123] 6. The RU derives both analog and digital beamforming weights. The RU decodes the analog / digital beamforming weights directly from C-plane messages or using beam IDs included in the codebook. In this way, it determines the hybrid beamforming settings per target resource element.

[0124] 7. The RU applies analog and digital beamforming weights. The RU applies hybrid beamforming.

[0125] In some embodiments of step 2 of FIG. 8, the DU transmits the codebook required for the candidate space combination method.

[0126] Downselection requirement in the DU's codebook: The DU sends a requirement to downselect a specific or multiple codebooks for the shortened bit width in Step 2.

[0127] Downselection by application scenario: Codebook downselection is assigned to a specific application. For example, in DL, the codebook for a phase shifter value is not subject to downselection. In UL, the same codebook is downselected for each phase shifter value.

[0128] In some embodiments, the RU may have multiple configuration or option groups. The RU informs the DU of the hybrid beamforming configuration groups supported through the M-plane. The DU sets a group number to the RU, and the RU applies the corresponding hybrid beamforming configuration.

[0129] M-Plane Signaling Design: During the initial handshake phase between the RU and the DU, the RU first transmits beamforming configuration information to the DU via the M-plane as in Step 1 of FIG. 8. Detailed signaling for Steps 1 and 3 is described as follows.

[0130] In M-plane signaling, the DU requests a beamforming configuration report from the RU in part[1]. The RU responds to the request by sending the beamforming configuration in part[2] in a predefined format. Codebooks for digital and analog beamforming are included. The DU receives the codebooks, optionally downselects them, and then sends the downselected codebooks back to the RU in part[3]. The RU sends an acknowledgment in part[4] regarding whether the downselection has been accepted and the downselection to be applied.

[0131] In one embodiment, the following is added to the Yet Another Next Generation (YANG) data modeling language model for M-plane hybrid beamforming setups.

[0132] groupinghybrid-bf-configuration {

[0133] leafhybrid-bf-analog-phase-shifter-parameter {

[0134] type enumeration {

[0135] enum CTRL_BITS {

[0136] Description

[0137] "The analog phase-shifter is configured by control bit-vector. The codebook of bit-vector to phase mapping is configured through M-plane.";

[0138] }

[0139] enum IQ_VALUES {

[0140] description "The analog phase-shifter is configured by through a pair of I / Q values.";

[0141] }

[0142] }

[0143] }

[0144] leaf phase-shifter-bitwidth {

[0145] type uint4;

[0146] mandatory true;

[0147] description "the bit-width of the phase-shifter's control bit-vector or I / Q values.";

[0148] }

[0149] leaf analog-beam-id-bitwidth {

[0150] type uint4;

[0151] mandatory true;

[0152] description "the bit-width of the analog beam ID.";

[0153] }

[0154] leaf analog-beam-group-bitwidth {

[0155] type uint4;

[0156] default 15;

[0157] mandatory true;

[0158] description "the bit-width of the analog beam ID.";

[0159] }

[0160] leaf is-digital-analog-beam-id-coupled {

[0161] type boolean;

[0162] mandatory true;

[0163] description "If true, the beam ID of the hybrid BF is associated with both digital and analog BF weights.

[0164] If false, the digital and analog BF have separate beam ID codebooks.";

[0165] }

[0166] container phase-shifter-codebook {

[0167] when ".. / hybrid-bf-analog-phase-shifter-parameter = CTRL_BITS";

[0168] list control-bit-vector {

[0169] key control-bit-vector;

[0170] leaf phase-value {

[0171] type dicimal64 {

[0172] fraction-digits 2;

[0173] }

[0174] description "The phase value in degree.";

[0175] }

[0176] description "The mapping from the control bit-vector to the actual phase value."; }

[0177] }

[0178] container analog-beam-id-codebook {

[0179] list analog-beam-id {

[0180] key beam-id;

[0181] leaf bit-vector-config {

[0182] type uint16;

[0183] }

[0184] description "The beam ID of TRX control. The effective beam ID is on the LSBs. The bit-width is indicated by .. / analog-beam-id-bitwidth.";

[0185] }

[0186] }

[0187] container analog-beam-group-id {

[0188] list analog-beam-group-id {

[0189] key beam-group-id;

[0190] leaf beam-id-config {

[0191] type uint16;

[0192] }

[0193] description "The analog beam group ID of analog BF configuration.";

[0194] }

[0195] }

[0196] }

[0197] In this example YANG model, the RU reports the hybrid beamforming configuration to the DU via "hybrid-bf-configuration". The RU can support two types of analog phase shifter configuration options.

[0198] CTRL_BITS: RU uses a control bit vector to set the phase shifter value. A codebook representing the correspondence between the bit vector and the actual value is transmitted via the M-plane (.. / phase-shifter-control).

[0199] IQ_VALUES: This option is intended to support phase shifter configuration based on the existing O-RAN specification, i.e., I / Q value transmission.

[0200] The bit width of the phase shifter control bit vector is set to "phase-shifter-bitwidth". The bit width of the analog beam ID is set to "analog-beam-id-bitwidth". These two bit widths are reported from the RU to the DU via the M-plane. These bit widths are used in C-plane messages.

[0201] The bit width of the analog beam group ID is set in "analog-beam-group-bitwidth". The default value is 15, and a value per RU can be optionally specified.

[0202] The RU can optionally have a single overall beam ID associated with both digital and analog beamforming weights by using the "is-digital-analog-beam-id-coupled=true" setting. Additionally, the RU can separate the digital and analog beamforming weights to associate a specific beam ID only with the digital beamforming weights.

[0203] The analog beam group ID and beam ID are associated with analog beamforming weights using "is-digital-analog-beam-id-coupled=false".

[0204] In the YANG model above, analog beamforming-related codebooks are configured as containers such as "phase-shifter-codebook", "analog-beam-id-codebook", and "analog-beam-group-id".

[0205] An example of "phase shifter codebook" mapping is shown in Table 1.

[0206]

[0207] In some embodiments, the RU transmits multiple "hybrid-bf-configuration" groups to the DU. Each "hybrid-bf-configuration" group represents a group of different configurations. The DU selects one of the "hybrid-bf-configuration" groups for a hybrid beamforming configuration and transmits the group number to the RU via the M-plane.

[0208] C-plane signaling design: In step 5 illustrated in Fig. 8, the DU transmits the hybrid beamforming settings to the RU via a C-plane message.

[0209] The analog phase shifter is set by the control bit vector.

[0210] The bit width of the analog beam ID follows the M-plane settings according to steps 1 to 3 of FIG. 8.

[0211] Each analog beam group ID, analog beam ID, analog control bit vector, digital beam ID, and digital beamforming weight is designed with a control bit indicating whether the corresponding information is disabled.

[0212] Section extension for hybrid beamforming setup: An example of a hybrid beamforming C-plane setup is shown as a section extension in Table 2 below.

[0213]

[0214]

[0215] In the SE-X header (the first 6 lines of Table 2), the fields "disableAnaBfws" (control for turning analog beamforming weights on / off), "analogBeamGroupId[14:8]", and "analogBeamGroupId[7:0]" were present in ST4 but were not in the existing SE header. The SE-X header introduced on / off controls for the digital beam ID ("disableDigBeamId") and the analog beam ID ("disableAnaBeamId"). The disableAnaBeamId control is specialized for controlling the presence of the analog beam ID and does not control the analog beamforming weights (this is a difference from ST4). In the analog beamforming weight setting section of Table 2 (the 7th line following the header), the "analogBeamId" for transceivers 0 through K' were also present in ST4. The "tdBfParamPhase" variable, which is the control bit vector for each phase shifter, was newly added. The remainder of Table 2 contains the subband-specific digital beamforming weight settings (PRB bundles) that existed in SE11 of the O-RAN specification.

[0216] In one embodiment, the DU uses a new section expansion X (SE-X) to set digital and analog beamforming weights. The SE-X format is shown in Table 2 and includes: 1) a section expansion header, 2) weight / beam IDs of digital / analog beamforming indicators, 3) hybrid beamforming specific settings, 4) analog beamforming weight settings, and 5) digital beamforming weight settings per subband.

[0217] The description of the SE-X format item in Table 2 is as follows.

[0218] 1) Section extension header:

[0219] The header uses the basic format of the O-RAN specification and includes the following.

[0220] i. "ef" as an extension flag indicating whether another section extension is currently connected to SE-X.

[0221] ii. "extType=0x0X" serves as the index for the section type, and X must be entered here.

[0222] iii. "extLen" as the full length of the SE-X word. A heavy digital BF weighting setting is required for the adaptation scenario, and "extLen" occupies 2 bytes.

[0223] 2) Digital / Analog BF Indicator Weight / Beam ID:

[0224] The presence of beamforming weights or beam IDs for analog or digital beamforming is indicated by 4 bits. In this way, the DU has the flexibility to apply SE-X in various scenarios without redundancy of unnecessary information.

[0225] i. "disableDigBfws" as a flag indicating whether digital beamforming weights are disabled. A value of 0 means that digital beamforming weights are included in SE-X, and a value of 1 means that digital beamforming weights are not included in SE-X. This bit exists in the O-RAN specification.

[0226] ii. "disableDigBeamId" as a new flag indicating whether to disable digital beam ID. A value of 0 means that the digital beam ID is included in SE-X, and a value of 1 means that the digital beam ID is not included in SE-X.

[0227] iii. "disableAnaBfws" as a new flag indicating whether to disable analog beamforming weights. A value of 0 means that analog beamforming weights are included in SE-X, and a value of 1 means that analog beamforming weights are not included in SE-X.

[0228] iv. "disableAnaBeamId" as a new flag indicating whether to disable the analog beam ID. A value of 0 means that the analog beam ID is included in SE-X, and a value of 1 means that the analog beam ID is not included in SE-X.

[0229] v. "RAD" as an indicator of resetting after PRB discontinuity, as was present in SE11 of the O-RAN specification.

[0230] In some embodiments, the metric value also affects the presence of other variables of SE-X. For example, if there is no digital beamforming weight, there is no compression command to reduce C-plane message traffic. The changes in SE-X according to the digital / analog beamforming weight / beam ID metric are summarized in Table 3 below for digital beamforming and in Table 4 below for analog beamforming.

[0231]

[0232]

[0233] 3) hybrid BF Specific settings:

[0234] i. "numBundPrb" indicates the number of PRB bundles or subbands for a digital beamforming setup. This feature exists in SE11 of the O-RAN specification.

[0235] ii. "analogBeamGroupId" occupies 15 bits and maps to the K value of all phase shifters. Mapping "analogBeamGroupId" to the analog beam ID of each transceiver is optional. If the analog beam ID and / or analog beamforming weights are included in SE-X, the RU associates "analogBeamGroupId" with the analog beam ID and / or analog beamforming weights for use in future incoming C-plane messages.

[0236] iii. "digBfwCompHdr" is a digital beamforming weighted compression header that follows the same definition as the O-RAN specification, and does not exist when "disableDigBfws=1" is set.

[0237] 4) Analog Beamforming Weight settings:

[0238] If the value of either "disableAnaBfws" or "disableAnaBeamId" is 0, analog beamforming weight setting information for a total of K' groups is transmitted. In each group:

[0239] i. "analogBeamId" contains the analog beam ID of a specific transceiver. The bit width of "analogBeamId" is set in the M-plane in steps 1 through 3 of FIG. 8. If "disableAnaBeamId=1" is set, "analogBeamId" is not displayed; otherwise, only one "analogBeamId" exists per transceiver.

[0240] ii. "tdBfParamPhase" contains a phase setting for the phase shifter of a specific transceiver. The bit width of "tdBfParamPhase" is set in the M-plane in steps 1 through 3 of FIG. 8. If "disableAnaBfws = 1", "tdBfParamPhase" does not exist, otherwise K / K' "tdBfParamPhase" exist per transceiver.

[0241] 5) Digital by Subband Beamforming weight settings

[0242] Digital beamforming allows for fine-tuning on a per-subband basis. The subband width is related to the PRB range set in the section type header and the "numBundPrb" value in SE-X. For each subband:

[0243] i. "digBfwCompParam" contains parameters for digital beamforming weighted compression that follow the same definition as the O-RAN specification, but does not exist when "disableDigBfws=1" is set.

[0244] ii. "beamId" is a 15-bit digital beam ID associated with a specific digital beamforming weight. If a digital beamforming weight exists in SE-X, the RU associates that digital beamforming weight with this "beamId" for use in future C-plane messages. If "disableDigBeamId = 1", no "beamId" exists; otherwise, one "beamId" exists per subband.

[0245] iii. "bfwI" and "bfwQ" are digital beamforming weights. If "disableDigBfws=0", there are a total of K' pairs of "bfwI" and "bfwQ"; otherwise, no digital beamforming weights exist. "bfwI" and "bfwQ" are controlled by "digBfwCompHdr" in the SE-X header, and "digBfwCompParam" is specified per subband.

[0246] iv. "contInd" is a PRB region continuity flag, similar to that in SE11 of the O-RAN specification.

[0247] Additional variants of the SE-X:

[0248] In some embodiments, some or all of the SE-X for disabling analog / digital beamforming weights / beam IDs may not exist. Analog / digital beamforming weights / beam IDs may always be present or may not always be present.

[0249] In some embodiments, the three reserved bits in the row following "extLen" are used to indicate the number of analog beamforming weights per analog port. For example, they are used as "numAnaBfVal=N" or "numAddiAnaBfVAl=N-1", where N is the number of values ​​required for the analog beamforming weights. By default, SE-X requires only one value for the analog beamforming weights, which is the control bit vector for the phase shifter (set in the M-plane). However, to accommodate other configurations (e.g., when I / Q values ​​per phase shifter are preferred), "numAnaBfVal" is 2 or "numAddiAnaBfVAl" is 1. In some scenarios requiring both the phase shifter I / Q values ​​and power amplifier configurations (three values), "numAnaBfVal" is 3 or "numAddiAnaBfVAl" is 2. The meaning and order of analog beamforming values ​​are defined through the M-plane. In SE-X, "tdBfParamPhase" is replaced by "tdBfParam1", "tdBfParam2", ..., "tdBfParamN" for each analog port of the transmitter and receiver.

[0250] In some embodiments, zero padding exists after a) the analog beamforming setting of each transceiver, b) the overall analog beamforming setting, and c) each subband of the digital beamforming setting.

[0251] Example of Hybrid BF Configuration Using SE-X - Phase Shifter Control Bit Vector vs. I / Q.

[0252] For example, the RU has K=1024 analog ports and K'=64 digital ports. In one scenario, the DU sets analog beamforming weights to the RU through the C-plane.

[0253] 1) In the above YANG model, if "hybrid-bf-analog-phase-shifter-parameter" is set to "CTRL_BITS":

[0254] As shown in Table 1, it is assumed that the control bit vector is 4 bits. An example of analog beamforming weight settings in SE-X is shown in Table 5 below (a total of 4 × 1024 = 4096 bits are used for analog beamforming weight settings).

[0255]

[0256] 2) In the above YANG model, if "hybrid-bf-analog-phase-shifter-parameter" is set to "IQ_VALUES":

[0257] Assuming control bit vectors and I / Q mappings as shown in Table 1, I / Q values ​​are expressed in an 8-bit format (e.g., block floating point). Examples of analog beamforming weight settings in SE-X are shown in Table 6 below (a total of 8 × 2 × 1024 = 16,384 bits are used for analog beamforming weight settings).

[0258]

[0259] FIG. 9 illustrates an example of a hybrid weighted dynamic beamforming setup that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure.

[0260] The embodiment of the hybrid weight-based dynamic beamforming setup (900) illustrated in FIG. 9 is for illustrative purposes only. FIG. 9 does not limit the scope of the present disclosure to a specific hybrid weight-based dynamic beamforming setup.

[0261] For example, the RU has K analog ports, K' transceivers, and L data layers. The common header of ST1 requires 16 bytes. The C-plane message consists of ST1 (including the SE-X header proposed herein) having a layer-specific value (901) (for each data layer) as illustrated in FIG. 9. For each layer, the section header uses 8 bytes and the SE-X header uses 8 bytes.

[0262] Both analog and digital beamforming weights must be transmitted from the DU to the RU. Accordingly, an embodiment of the hybrid weight-based dynamic beamforming setup (900) of FIG. 9 includes analog values ​​(902) for each layer. For analog beamforming, both an analog beam ID and a phase shifter value are required for each transceiver. Accordingly, the layer-specific value (901) includes an analog beamforming value (902) for an analog beamforming weight required only for the first layer, which may be an analog beam ID and the corresponding analog beamforming weight. The configured analog beam group ID may be the same across all layers.

[0263] For the analog beamforming value (902), the analog beam ID and analog beamforming weight are transmitted in the first layer. A total of W*(K+K') bytes are transmitted. In the remaining layers, the analog beam ID and analog beamforming weight are disabled. The RU uses the analog beam group ID of the SE-X header associated with the same analog beam ID and beamforming weight in the first layer.

[0264] In the case of digital beamforming, since the digital beamforming weights (903) are set and transmitted per subband, the layer values ​​(901) contain a set of digital values ​​(904a to 904m) for each of the M subbands. W bytes are required for each beamforming weight and each beam ID. For each subband, 1 byte is used for the compression header, and 2*W*K' bytes are used for the weights.

[0265] In this example, the total length of the C-plane message to implement the hybrid BF setup is 16 + L*(8+8+M*(1+2+W*K')) + (W*K'+K) bytes. The digital "beamId" (905) of each layer can be disabled or set not to be transmitted, and (assuming 273 subbands and 64 layers) in this case, 2 bytes × 273 subbands × 64 layers = 34944 bytes can be saved.

[0266] FIG. 10 illustrates an example of a hybrid CSI-based beamforming setup that can be used in connection with hybrid beamforming for O-RAN fronthaul according to an embodiment of the present disclosure.

[0267] An example of the hybrid CSI-based beamforming setup (1000) illustrated in FIG. 10 is for illustrative purposes only. FIG. 10 does not limit the scope of the present disclosure to a specific hybrid CSI-based beamforming setup.

[0268] In the illustrated hybrid CSI-based beamforming configuration (1000), the RU has K analog ports, K' transceivers, and L data layers. The DU requires a UE ID because the RU is configured to use CSI-based beamforming for digital beamforming (associated with ueId). UE ID information (1001) is transmitted using ST5 and SE10. The common header of ST5 requires 16 bytes. The section description requires 8 bytes, including the UE ID of the representative layer. SE10 requires 3 bytes for the header and 2 bytes for each of the remaining layers.

[0269] For analog beamforming (BF), an analog phase shifter value is required for each transceiver. Simply put, W bytes are required for each BF weight and each beam ID. The C-plane message consists of ST5, SE10, and SE-X for each data layer, as illustrated in FIG. 10. SE-X has a 4-byte header, and for analog beamforming, the analog beam ID and analog BF weight are transmitted together, which are transmitted as an analog beamforming configuration (1002). The total length is W*(K+K') bytes. Therefore, in this example, the total length of the C-plane message to implement the hybrid BF configuration is 16 + 8 + 3 + 2*(L-1) + 4+2+W*K bytes.

[0270] In some embodiments, the analog phase shifter value is transmitted directly to the RU and compressed similarly to the digital BF weight. As shown in Table 7, both "anaBfwCompHdr" and "anaBfwCompParam" are added to the header of SE-X1.

[0271]

[0272]

[0273] As shown in Table 8, "anaBfwCompParam" also exists per transceiver rather than in the header.

[0274]

[0275]

[0276] Section type of hybrid BF setup: In some embodiments, the hybrid beamforming C-plane setup is transferred as a section type.

[0277] One example is shown in Table 9.

[0278]

[0279]

[0280] The field of ST-X for the hybrid beamforming setup is the same as that of SE-X shown in Table 2. Variations of SE-X are also applicable to ST-X.

[0281] In the second embodiment, the beamId of section type 1 is designed as the hybrid beam ID of the hybrid BF RU, and is as follows:

[0282] The ST1 beam ID is reinterpreted as a hybrid beam ID. The hybrid beam ID is associated with a specific pair of analog beam group IDs and digital beam IDs.

[0283] The DU and RU infer the analog beam group ID and digital beam ID from the hybrid beam ID based on a predefined function or mapping table. In this case, the analog beam group ID and digital beam ID are not explicitly signaled in the C-plane.

[0284] A mapping table or predefined function is transmitted from the RU to the DU via M-plane signaling in step 1 of Fig. 8.

[0285] When the analog beam group ID and digital beam ID are derived, the RU transmits the analog beam group ID and digital beam ID to another processor or dedicated integrated circuit.

[0286] If the analog beam group ID and / or digital beam ID are associated with analog and / or digital beam frequency weights, the analog and digital beam frequency weights can be obtained.

[0287] Analog or digital BF weights are required in C-plane messages only when the DU intends to associate a new weight with an analog beam group ID or a digital beam ID.

[0288] The bit width of the hybrid beam ID is identified in the M-plane and does not necessarily have to be 15 bits by default.

[0289] FIG. 11 illustrates an example of mapping from a hybrid beam ID to an analog beam group ID and a digital beam ID according to an embodiment of the present disclosure.

[0290] The embodiment of the mapping (1100) illustrated in FIG. 11 is for illustrative purposes only. FIG. 11 does not limit the scope of the present disclosure to a specific mapping.

[0291] Mapping (1100) associates the hybrid beam ID (1101) with the analog beam group ID (1102) and the digital beam ID (1103). The analog beam group ID (1102) and the digital beam ID (1103) further specify analog and digital beamforming, and the analog beam group ID (1102) is mapped to the analog beam ID (1104) per transceiver, and the analog beam group ID (1102) and the analog beam ID (1104) per transceiver are mapped to the analog beamforming weight set (1105) per transceiver. The digital beam ID (1103) is mapped to the digital beamforming weight set (1106) per transceiver. Beamforming configuration information is required when the mapping between the hybrid beam ID and the beamforming weights is unknown or overwritten. Otherwise, since this information exists in the RU, the DU does not need to transmit the information in the C-plane.

[0292] Mapping setup from M-plane hybrid beam ID to analog beam group ID: In one embodiment, mapping from hybrid beam ID to analog beam group ID and digital beam ID exists in the YANG model. In step 1 of FIG. 8, the RU transmits the mapping through the M-plane along with other hybrid BF-related M-plane messages.

[0293] FIG. 12 illustrates an alternative example of hybrid beamforming used in connection with an O-RAN fronthaul according to an embodiment of the present disclosure.

[0294] The embodiment of the signaling (1200) illustrated in FIG. 12 is for illustrative purposes only. FIG. 12 does not limit the scope of the present disclosure to a specific implementation of the signaling.

[0295] Figure 12 is an update of Figure 8 with added description of the hybrid beam ID mapping transmission in Step 1. The leaf “is-digital-analog-beam-id-coupled” of the “hybrid-bf-configuration” of the YANG model is set to true, which means that the digital beam ID and the analog beam group ID are combined into a hybrid beam ID in ST1.

[0296] M-plane Hybrid Beam ID Mapping: In one embodiment, the hybrid beam ID is a composite of an analog beam group ID and a digital beam ID. For example, the hybrid beam ID is 15 bits, the first 7 bits being the analog beam group ID and the remaining 8 bits being the digital beam ID.

[0297] In another embodiment, the hybrid beam ID is a function of the analog beam group ID and the digital beam ID. The mapping from the hybrid beam ID to the analog beam group ID and the digital beam ID is transmitted dynamically through the M-plane or the C-plane.

[0298] The RU transmits the mapping from the hybrid beam ID to the analog beam group ID and the mapping to the digital beam ID to the DU via the M-plane. The analog beam group ID and the digital beam ID do not need to be explicitly transmitted.

[0299] In some embodiments, the mapping is formed in the form of a list. That is, it is a list that maps hybrid beam IDs to analog beam group IDs and digital beam IDs, where the digital beam IDs act as leaf nodes. For example, as follows.

[0300] groupinghybrid-bf-configuration {

[0301] …

[0302] leaf-list hybrid-beam-id-mapping {

[0303] key hybrid-beam-id;

[0304] leaf analog-beam-group-id {

[0305] type uint16;

[0306] description "the analog beam group ID.";

[0307] }

[0308] list digital-beam-id {

[0309] type uint16;

[0310] description "the digital beam ID.";

[0311] }

[0312] description "the hybrid beam ID.";

[0313] }

[0314] …

[0315] }

[0316] In some implementation examples, the mapping is formed in a "list of lists" manner. A list of hybrid beam IDs is transmitted, and each hybrid beam ID contains two lists. As an example in FIG. 13, one is a list for analog beam group IDs and the other is a list for digital beam IDs.

[0317] FIG. 13 illustrates an example of an alternative mapping from a hybrid beam ID to an analog beam group ID and a digital beam ID according to an embodiment of the present disclosure.

[0318] The embodiment of the mapping (1300) illustrated in FIG. 13 is for illustrative purposes only. FIG. 13 does not limit the scope of the present disclosure to a specific mapping.

[0319] The mapping (1300) connects the hybrid beam ID (1301) as the first key, the analog beam group ID (1302) as the second key, the analog beamforming weight (1303) as the associated leaf, the digital beam ID (1304) as the third key, and the digital beamforming weight (1305) as the associated leaf.

[0320] An example of the YANG model is as follows (other leaves of the hybrid-bf-configuration use the above YANG model).

[0321] groupinghybrid-bf-configuration {

[0322] …

[0323] list hybrid-beam-id-mapping {

[0324] key hybrid-beam-id;

[0325] list analog-beam-group-id-mapping {

[0326] key analog-beam-group-id;

[0327] container analog-bf-weight {

[0328] leaf analog-control-bit-vector {

[0329] type uint16;

[0330] }

[0331] }

[0332] description "the analog beam group ID.";

[0333] }

[0334] list-digital-beam-id-mapping {

[0335] key digital-beam-id:

[0336] container digital-bf-weight {

[0337] leaf digital-bf-weight-i {

[0338] type uint16;

[0339] }

[0340] leaf digital-bf-weight-q {

[0341] type uint16;

[0342] }

[0343] }

[0344] description "the analog beam group ID.";

[0345] }

[0346] description "the hybrid beam ID.";

[0347] }

[0348] …

[0349] }

[0350] For example, there are a total of 4 analog beam group IDs and 5 digital beam IDs. The hybrid beam IDs range from 1 to 20 and are as follows.

[0351] Hybrid Beam IDs: #1~#5 represent analog beam group ID=1 and digital beam IDs=1~5.

[0352] Hybrid beam IDs: #6~#10 represent analog beam group ID=2 and digital beam IDs=1~5.

[0353] Hybrid beam IDs: #11~#15 represent analog beam group ID=3 and digital beam IDs=1~5.

[0354] Hybrid beam IDs: #16~#20 represent analog beam group ID=4 and digital beam IDs=1~5.

[0355] Assuming K=4 and K'=2, the following is an example of mapping between hybrid beam IDs, analog beam groups, and digital beam IDs in a JavaScript Object Notation (JSON) file. The "hybrid-beam-id-mapping" file contains a total of 20 mappings between hybrid beam IDs, analog beam groups, and digital beam IDs. The first 5 have the same analog beam group ID and analog control bit vector, while the digital beam ID and digital beam frame (BF) weights are different. In the 6th "hybrid-beam-id", the analog beam group ID is different from the first 5, and the digital beam ID is the same as the 1st "hybrid-beam-id". In the last "hybrid-beam-id", the analog beam group ID is different from the first 15, and the digital beam ID is the same as the 5th "hybrid-beam-id".

[0356] .

[0357] "hybrid-bf-configuration": {

[0358] "hybrid-beam-id-mapping": {

[0359] {"hybrid-beam-id" : 0x00;

[0360] "analog-beam-group-id-mapping": {

[0361] "analog-beam-group-id": 00b;

[0362] "analog-bf-weight": [00, 00, 00, 00];

[0363] }

[0364] "digital-beam-id-mapping": {

[0365] "digital-beam-id": 000b;

[0366] "digital-bf-weight-i": [0x00, 0x00];

[0367] "digital-bf-weight-q": [0x01, 0x01];

[0368] }

[0369] }

[0370] {"hybrid-beam-id" : 0x01;

[0371] "analog-beam-group-id-mapping": {

[0372] "analog-beam-group-id": 00b;

[0373] "analog-bf-weight": [00, 00, 00, 00];

[0374] }

[0375] "digital-beam-id-mapping": {

[0376] "digital-beam-id": 001b;

[0377] "digital-bf-weight-i": [0x01, 0x01];

[0378] "digital-bf-weight-q": [0x01, 0x01];

[0379] }

[0380] }

[0381] {"hybrid-beam-id" : 0x02;

[0382] "analog-beam-group-id-mapping": {

[0383] "analog-beam-group-id": 00b;

[0384] "analog-bf-weight": [00, 00, 00, 00];

[0385] }

[0386] "digital-beam-id-mapping": {

[0387] "digital-beam-id": 010b;

[0388] "digital-bf-weight-i": [0x10, 0x10];

[0389] "digital-bf-weight-q": [0x01, 0x01];

[0390] }

[0391] }

[0392] {"hybrid-beam-id" : 0x03;

[0393] "analog-beam-group-id-mapping": {

[0394] "analog-beam-group-id": 00b;

[0395] "analog-bf-weight": [00, 00, 00, 00];

[0396] }

[0397] "digital-beam-id-mapping": {

[0398] "digital-beam-id": 011b;

[0399] "digital-bf-weight-i": [0x11, 0x11];

[0400] "digital-bf-weight-q": [0x00, 0x00];

[0401] }

[0402] }

[0403] {"hybrid-beam-id" : 0x04;

[0404] "analog-beam-group-id-mapping": {

[0405] "analog-beam-group-id": 00b;

[0406] "analog-bf-weight": [00, 00, 00, 00];

[0407] }

[0408] "digital-beam-id-mapping": {

[0409] "digital-beam-id": 100b;

[0410] "digital-bf-weight-i": [0x00, 0x00];

[0411] "digital-bf-weight-q": [0x11, 0x11];

[0412] }

[0413] }

[0414] {"hybrid-beam-id" : 0x05;

[0415] "analog-beam-group-id-mapping": {

[0416] "analog-beam-group-id": 01b;

[0417] "analog-bf-weight": [10, 00, 10, 00];

[0418] }

[0419] "digital-beam-id-mapping": {

[0420] "digital-beam-id": 000b;

[0421] "digital-bf-weight-i": [0x00, 0x00];

[0422] "digital-bf-weight-q": [0x01, 0x01];

[0423] }

[0424] }

[0425] ……

[0426] {"hybrid-beam-id" : 0x14;

[0427] "analog-beam-group-id-mapping": {

[0428] "analog-beam-group-id": 11b;

[0429] "analog-bf-weight": [11, 01, 11, 01];

[0430] }

[0431] "digital-beam-id-mapping": {

[0432] "digital-beam-id": 100b;

[0433] "digital-bf-weight-i": [0x00, 0x00];

[0434] "digital-bf-weight-q": [0x11, 0x11];

[0435] }

[0436] }

[0437] }

[0438] }

[0439] In some embodiments, mapping is formed via a remote procedure call (RPC) in the YANG model. The analog beam group ID is derived from the hybrid beam ID as follows:

[0440] analog beam group ID = floor(hybrid beam ID / 5),

[0441] Here, B = floor(A) rounds the elements of A to the nearest integer less than or equal to A.

[0442] The digital beam ID is derived from the hybrid beam ID as follows:

[0443] digital beam ID = mod(hybrid beam ID, 5),

[0444] Here, the function C = mod(A, B) returns the remainder after division (modulo operation), i.e.,

[0445] C = A - B * floor(A / B).

[0446] The functional relationship between the analog beam group ID, digital beam ID, and hybrid beam ID is defined using RPC. An example of the YANG model is as follows.

[0447] modulehybrid-beam-id-decode {

[0448] namespace "urn:hybrid-beam-id-decode";

[0449] prefix "hb";

[0450] rpc custom-operation {

[0451] input {

[0452] leaf hybrid-beam-id {

[0453] type uint32;

[0454] description "Input parameter X for the operation, which is The ID of the hybrid beam";

[0455] }

[0456] leaf num-digital-beam-id {

[0457] type uint32;

[0458] description "Input parameter Y for the operation, which is the total number of digital beams";

[0459] }

[0460] }

[0461] output {

[0462] leaf analog-beam-group-id {

[0463] type uint32;

[0464] description " analog-beam-group-id equals to floor(X / Y).";

[0465] }

[0466] leaf digital-beam-id {

[0467] type uint32;

[0468] description " digital-beam-id equals to mod(X, Y).";

[0469] }

[0470] }

[0471] description "RPC operation interprets the hybrid beam ID to analog beam group ID and digital beam ID.";

[0472] }

[0473] }

[0474] FIG. 14 illustrates an example of a C-plane hybrid beamforming setup having digital beamforming weights according to an embodiment of the present disclosure.

[0475] An example of the setting (1400) illustrated in FIG. 14 is for illustrative purposes only. FIG. 14 does not limit the scope of the present disclosure to a specific setting.

[0476] C-plane hybrid beamforming setup with digital beamforming weights: In some embodiments, a hybrid beam ID with dynamic digital beamforming weights is transmitted from the DU to the RU via the C-plane. An analog beam group ID is inferred from the hybrid beam ID at the RU. The analog beam ID and the analog beamforming weights associated with the analog beam group ID are inferred at the RU.

[0477] In the example setup (1400) illustrated in FIG. 14, the analog BF setup is entirely present in the hybrid beam ID (1401). For wideband digital beamforming (WDBF), the digital beamforming weights are transmitted using SE-X (1402).

[0478] FIG. 15 illustrates an example of a C-plane hybrid beamforming setup having analog and digital beamforming weights according to an embodiment of the present disclosure.

[0479] An example of the setting (1500) illustrated in FIG. 15 is for illustrative purposes only. FIG. 15 does not limit the scope of the present disclosure to a specific setting.

[0480] C-plane hybrid beamforming configuration with analog and digital beamforming weights: The mapping between the analog beam group ID and the analog beam ID and / or analog beamforming weights can be dynamically configured in a C-plane message transmitted from the DU to the RU. If the analog beamforming configuration needs to be updated, the hybrid beam ID, analog beam group ID, and digital beam ID are explicitly included in the same section description and transmitted from the DU to the RU via the C-plane. In some embodiments, the RU configures the mapping to be used in the remaining section description for future reuse.

[0481] In the example illustrated in FIG. 15, the C-plane message (1501) is composed of a first section (1502) and another section (1503) for a different layer / subband using ST1 (1504, 1505) and SE-X (1506, 1507). The analog beam group IDs of SE-X (1506, 1507) are disabled but can be interpreted from the hybrid beam IDs of ST1 (1504, 1505). SE-X (1506) for the first section (1502) includes an analog control bit vector and digital beamforming weights, while SE-X (1507) for the other section includes only digital beamforming weights. That is, the analog beamforming settings are omitted in the remaining sections that have the same analog beamforming settings.

[0482] Two examples of SE-X messages for the first section and the remaining sections are shown in Table 10 and Table 11, respectively.

[0483]

[0484]

[0485]

[0486] The variation from SE-X to SE-X3 in Table 2 is the addition of "disableAnaBeamGroupId". In the second embodiment, since the analog beam group ID is resolved, the analog beam group ID can be disabled through "disableAnaBeamGroupId=1".

[0487] In the third embodiment:

[0488] Digital beamforming settings are transmitted via existing SEs such as SE1 and SE11.

[0489] Analog beamforming settings are signaled as section extension or section type, regardless of digital beamforming.

[0490] The RU applies the latest analog beamforming setting until it receives a new analog beamforming setting from the DU via the C-plane. That is, when an analog beamforming change is required, the DU transmits a section extension for the analog beamforming setting.

[0491] Analog configuration via section expansion: In one embodiment, the analog beam group ID, analog beam ID, and analog control bit vector are transmitted via section expansion as shown in Table 12.

[0492]

[0493] The control bit vector can be disabled via the "disableAnaBfws" command.

[0494] In another embodiment, the analog beam group ID and the analog control bit vector are transmitted via section expansion as shown in Table 12. The control bit vector can be disabled via "disableAnaBfws" as shown in Table 13.

[0495]

[0496] When set to "disableAnaBfws=1", there is no analog control bit vector in SE-Y1. The DU sets only the analog beam group ID in the RU.

[0497] When the second embodiment is applied, that is, when the analog beam group ID is inferred from the hybrid beam ID, SE-Y2 shown in Table 14 is The analog beam ID and control bit vector are transmitted from the DU to the RU.

[0498]

[0499] An example of transmitting only the analog control bit vector is shown in Table 15.

[0500]

[0501] The control bit vector of the K-phase converter is signaled in the form of a SE-Y3 queue.

[0502] FIG. 16 illustrates an example of a C-plane hybrid beamforming setup having analog and digital beamforming weights according to an embodiment of the present disclosure.

[0503] An example of the setting (1600) illustrated in FIG. 16 is for illustrative purposes only. FIG. 16 does not limit the scope of the present disclosure to a specific setting.

[0504] FIG. 16 illustrates a C-plane message for hybrid beamforming (BF) using SE-Y. In the example of FIG. 16, the C-plane message (1601) consists of a first section (1602) and another section (1603) for a different layer / subband via ST1 (1604, 1605), SE-Y (1606), and SE11 (1607, 1608). In the first section (1602), the hybrid beam ID is transmitted from the DU to the RU via the first section of ST1 (1604). SE-Y (1606) (or SE-Y1, SE-Y2, SE-Y3 depending on the scenario) It is used for setting analog beamforming weights. SE11 (1607, 1608) is used for setting digital beamforming weights. In other sections (1603) within ST1 (1605), the hybrid beam ID of the section description has the same analog beam group ID. The digital beam ID may be different. Digital beamforming weights are transmitted via SE11.

[0505] Analog configuration via section type: In one embodiment, the analog beam group ID is transmitted using a section type. An example is shown in Table 16.

[0506]

[0507] In scenarios requiring an analog control bit vector, use SE-Y3 in Table 15 It can be used.

[0508] The current O-RAN CUS plane specification [1] supports the flexible transfer of beamforming weights from the O-DU to the O-RU using SE11 and ST1. This allows the O-DU to provide different beamforming weights for different PRBs within a single section, for example, to facilitate zero-focusing precoding. The O-DU provides the numBundPrb parameter to the O-RU to tell it the number of PRBs that are bundled together and share the same beamforming weight. Tables 17 and 18 illustrate SE11 of the current specification.

[0509]

[0510]

[0511] JPTA beamforming requires delay and phase settings for subband-specific beamforming in the network. Current O-RAN specifications do not support beamforming in terms of delay and phase regarding the transmission of beamforming weights between the DU and RU. Therefore, a dedicated JPTA fronthaul payload must be constructed for low-overhead transmission of beamforming parameters between the DU and RU.

[0512] This specification proposes fronthaul signaling and payload structures required for the implementation of JPTA beamforming. The signaling includes the following aspects.

[0513] RU capability signaling. The RU transmits its capability to the DU via M-plane signaling. For JPTA beamforming, this signaling includes the minimum supported latency, supported latency resolution, maximum number of JPTA beams, and other relevant parameters.

[0514] DU processing. The DU takes the RU capability as input and selects a subset of parameter values ​​to use for transmission. The parameters selected include the number of delay factors, the bit resolution of the delay, the bit width of the delay, the minimum delay, and the maximum number of JPTA beams (or equivalently the bit width of the JPTA beam ID).

[0515] Parameter set signaling transmission from DU to RU. The DU transmits the parameter configuration file to the RU using M-plane signaling. For example, delay parameters are transmitted through a YANG grouping called jpta-delay-parameters.

[0516] JPTA beamforming settings per UE / layer. For each scheduling opportunity, the DU transmits the per-UE beamforming settings to the RU. This is implemented through C-plane signaling using section types and extension functions.

[0517] FIG. 17 illustrates an example of a fronthole processing step used in connection with an O-RAN fronthole for JPTA according to an embodiment of the present disclosure.

[0518] The embodiment of the signaling (1700) illustrated in FIG. 17 is for illustrative purposes only. FIG. 17 does not limit the scope of the present disclosure to a specific implementation of the signaling.

[0519] Figure 17 illustrates the entire fronthaul processing steps for beamforming and UE data transmission. The key steps are RU capability signaling, parameter set signaling from the DU to the RU, and transmission of UE / layer-specific JPTA beamforming settings. In Step 1, the RU capability is signaled from the RU to the DU in the M-plane. In Step 2, the DU determines parameter values, such as the delay in the true time delay (TTD) element, based on the RU capability and the scheduling request. In Step 3, a parameter configuration file, such as JPTA delay values ​​and the mapping between the beamID and the JPTA beam, is transmitted from the DU to the RU in the M-plane. In Step 4, UE / layer-specific JPTA beamforming settings are transmitted from the DU to the RU in the C-plane. In Step 5, the RU loads beamforming settings, such as delay values ​​and digital beamforming values. In Step 6, downlink data is transmitted from the DU to the RU in the U-plane. In step 7, the RU applies beamforming to the received data and transmits it.

[0520] RU capability signaling. The RU signals supported parameter values ​​to the DU through M-plane signaling. For example, RU capability signaling may include the minimum supported delay time, bit precision of the delay value, and maximum supported bit width, as well as delay scaling parameters such as the position of the delay element and the number of rows and columns of the delay element. Example 1-1 shows an example of YANG grouping to implement delay parameter signaling.

[0521] Example 1-1. Delay Parameter Signaling:

[0522] grouping jpta-delay-parameters {

[0523] leaf num-delay-element {

[0524] type uint16 {

[0525] range "1..65535";

[0526] }

[0527] mandatory true;

[0528] description

[0529] "Maximum number of supported delay elements";

[0530] }

[0532] leaf num-delay-element-rows {

[0533] type uint16 {

[0534] range "1..65535";

[0535] }

[0536] mandatory true;

[0537] description

[0538] "Maximum number of rows of delay elements";

[0539] }

[0540] leaf num-delay-element-columns {

[0541] type uint16 {

[0542] range "1..65535";

[0543] }

[0544] mandatory true;

[0545] description

[0546] "Maximum number of columns of delay elements";

[0547] }

[0548] leaf delay-bitwidth {

[0549] type uint4 {

[0550] range "1..15";

[0551] }

[0552] default 2;

[0553] description

[0554] "Bit-width for delay at each element";

[0555] }

[0556] leaf delay-bitprecision {

[0557] type uint4 {

[0558] range "1..15";

[0559] }

[0560] mandatory true;

[0561] description

[0562] "Bit precision of TTD delays supported by RU. Unit is 0.1 ns";

[0563] }

[0565] leaf delay-min {

[0566] type uint4 {

[0567] range "1..15";

[0568] }

[0569] units half-nanoseconds;

[0571] mandatory true;

[0572] description

[0573] “Min delay value supported by RU”;

[0574] }

[0576] description "Common jpta beamforming delay parameters.";

[0577] }

[0578] Common Beamforming Parameter Setting. Based on the RU's capability signaling, the DU determines the common beamforming parameters to be used, including the JPTA's delay parameters, and transmits this information to the RU. The selection of common parameters can define a mapping between bits transmitted via control signaling and specific beamforming parameter values. For example, to represent the delay value at a specific TTD element, b as the transmitted bit sequence (length is the selected bit width Same as), The minimum delay selected in the M-plane, and If is the bit precision of the delay selected in the M-plane, then the bit sequence b The actual delay value corresponding to is given as follows.

[0579]

[0580] Here is a bit sequence b It is a function that converts to the corresponding decimal integer. In some embodiments, b go It is transmitted to the C-plane, and in other embodiments, to the M-plane.

[0581] The RU reports the capability for the JPTA beam ID length, and the DU confirms or down-selects a specific JPTA beam ID length as part of the common beamforming parameter settings (e.g., down-selecting between 7 bits and 15 bits). This additional selection of common beamforming parameters determines the payload size that conveys beamforming information per UE via C-plane signaling.

[0582] Beamforming parameters per UE. The DU can specify specific beamforming parameters per UE through C-plane signaling, which is implemented using the proposed section extension (SE) N (see description below) together with ST1.

[0583] Beamforming parameters can be specified via explicit signaling as part of the SE N, or can be preset in the M-plane via the JPTA beam ID. Table 19 illustrates the structure of the proposed SE N, with beamforming parameters explicitly specified.

[0584]

[0585] To explicitly specify beamforming parameters, disableBFWs is set to 0. In this case, SE N explicitly includes the delay and phase for JPTA beamforming and the digital beamforming weights for each PRB bundle.

[0586] Table 20 illustrates the structure of the proposed SE N, where the JPTA beam ID is included in the section extension instead of explicitly displaying the beamforming parameters.

[0587]

[0588] The choice not to explicitly specify beamforming parameters is indicated by setting disableBFWs to 1.

[0589] The fields included in SE N are as follows.

[0590] ef(extension flag). This parameter is used to indicate whether another extension exists (ef=1) or if this is the last extension (ef=0), just as in the current O-RAN CUS plane specification[1].

[0591] exType(ExtendedType). It is a 7-bit field representing the SE type.

[0592] exLen(extension length). This parameter provides the length of the SE in 32-bit (or 4-byte) words, as in the current O-RAN CUS plane specification[1]. Since the extension always contains at least one word (a word containing extType and extLen), the value 0 is reserved.

[0593] disableBFWs (disable beamforming weights). This parameter is used to indicate whether delay, phase, and digital beamforming weights are explicitly displayed as part of the SE (disableBFWs = 0) or displayed by transmitting a preset JPTA beam ID (disableBFWs = 1).

[0594] numBundPrb (size of each PRB bundle). This 8-bit field indicates the number of PRBs included in each PRB bundle, i.e., the number of PRBs sharing the same digital beamforming weight, as in the current O-RAN CUS plane specification[1]. The number of PRB bundles (R) must be equal to the total number of PRBs selected from the section description of the C-Plane message (e.g., using the startPrbc and numPrbc fields of ST1) divided by numBundPrb. If the result of the division is a decimal, R is rounded up (i.e., one additional beamforming weight for each transceiver) to include the remainder PRB.

[0595] bfwCompHdr (Compression header for digital beamforming weights).

[0596] symbolMask (symbol bit mask). This parameter is a bit mask, where each bit indicates whether SE is applied to a specific symbol in the slot.

[0597] tdbfParamDelay(Delay at each delay element).

[0598] tdbfParamPhase (phase of each phase converter).

[0599] contInd (PRB area continuity flag).

[0600] bfw(Digital beamforming weight per PRB bundle).

[0601] In this case, the mapping between the JPTA beam ID and the delay and phase values ​​is established in the M-plane. Example 1-2 illustrates an example of YANG grouping for establishing this mapping.

[0602] Example 1-2. JPTA Beam ID Mapping:

[0603] container jptabeamId-codebook {

[0604] list jptabeamId {

[0605] key beam-id;

[0606] leaf bit-vector-config {

[0607] type uint16;

[0608] }

[0609] description "The beam ID for JPTA. The effective beam ID is on the LSBs.";

[0610] }

[0611] }

[0612] Example 1-3 illustrates a sample payload using SE N for JPTA beamforming. The gNB JPTA architecture (450) of FIG. 4A has five delay elements numbered 0, 1, 2, 3, and 4 that must report delay values ​​( ) and 4 phase shifters numbered 0, 1, 2, 3, and 4 that must report delay values ​​( It is assumed that ). Table 21 shows delay values ​​in nanoseconds (ns), and Table 22 shows phase values ​​in degrees (deg.).

[0613]

[0614]

[0615] Also, assume that the M-plane parameters are set as shown in Table 23.

[0616]

[0617] If disableBFWs is set to 0, the following Table 24 becomes the payload for SE N.

[0618]

[0619] In a second alternative embodiment, UE-specific JPTA beamforming parameters are conveyed through improvements to the existing Section Type 4 of the current O-RAN CUS plane specification[1]. In this case, a JPTA beam ID with a configurable bit width corresponds to a set of delay and phase values, and digital beamforming weights are defined for each PRB bundle. The JPTA beam ID and Delay value and The mapping between phase value tuples is defined in the M-plane similar to Example 1-2.

[0620] Table 25 illustrates the proposed improved section type 4.

[0621]

[0622] "Section type 4, which is the common part of the command header" is the same as the current O-RAN CUS plane specification[1]. For st4CmdType: JPTA_BEAM_CONFIG, you must set st4CmdType = 5.

[0623] FIG. 18 illustrates a schematic flowchart of a hybrid beamforming setup process according to an embodiment of the present disclosure.

[0624] The process (1800) illustrated in FIG. 18 is for illustrative purposes only, and FIG. 18 does not limit the scope of the disclosure to specific embodiments. The process (1800) may be performed by the controller / processor (340) of FIG. 3A or the controller / processor (378) of FIG. 3B in connection with the beamforming architecture (400) of FIG. 4 and / or the DU (501) of FIG. 5.

[0625] The DU (501) receives supported hybrid beamforming (BF) configuration information from the RU (502). This information includes the number of analog ports, the number of digital ports, the number of analog ports per transceiver, and supported codebooks (Block 1801). Based on the received information, the DU (501) determines whether to downselect the supported codebook (Block 1802) and generates a hybrid BF configuration including a control bit vector of a phase shifter mapped to a phase value, an I value, and a Q value (Block 1803). Finally, the DU (501) transmits the generated hybrid BF configuration to the RU (502) (Block 1804).

[0626] FIG. 18 shows one exemplary process (1800), but FIG. 18 may have various modifications. For example, FIG. 18 is shown as a series of steps, but various steps may overlap, occur in parallel, or occur multiple times.

[0627] Although the present disclosure has been described through exemplary embodiments, those skilled in the art may conceive of various changes and modifications. The present disclosure should be interpreted to encompass such changes and modifications that fall within the scope of the appended claims. Nothing in this application should be interpreted as implying that a particular element, step, or function is an essential element that must necessarily be included within the scope of the claims. The scope of the patentable subject matter is defined by the claims.

Claims

Claim 1 A method of a DU (distributed unit) of a communication system, comprising: receiving first information regarding a supported hybrid beamforming (BF) setting from a RU (radio unit) - the first information includes a number of analog ports, a number of digital ports, a number of analog ports per transceiver (TRX), and a supported codebook; generating a hybrid BF setting based on the supported codebook; and transmitting second information regarding the hybrid BF setting to the RU - the second information includes a control bit vector indicating a setting for a phase shifter of the RU; wherein a phase value, an in-phase (I) value, and an orthogonal phase (Q) value are mapped to one value of the control bit vector. Claim 2 A method of a DU according to claim 1, further comprising: a step of determining whether to down-select the supported codebook based on the first information; and a step of transmitting third information regarding the down-selected supported codebook to the RU when the DU decides to down-select the supported codebook, wherein the second information includes an analog BF setting applied to a frequency band and a digital BF setting applied to a subband within the frequency band. Claim 3 A method of a DU according to claim 1, further comprising the step of generating a control message including a first field indicating whether a digital beam ID (identifier) ​​is disabled and a second field indicating whether an analog beam ID is disabled; wherein the control message is transmitted together with the second information, and the bit width of the control bit vector is 4 bits. Claim 4 A method of DU according to claim 1, wherein the second information further comprises a delay value and a JPTA (joint phase-time array) beam ID (identifier) ​​mapped to the phase value. Claim 5 A method of a radio unit (RU) of a communication system, comprising: transmitting first information regarding a supported hybrid beamforming (BF) setting to a distributed unit (DU) - the first information includes a number of analog ports, a number of digital ports, a number of analog ports per transceiver (TRX), and a supported codebook; and receiving second information regarding a hybrid BF setting from the DU - the second information includes a control bit vector indicating a setting for a phase shifter of the RU; wherein a phase value, an in-phase (I) value, and an orthogonal phase (Q) value are mapped to one value of the control bit vector. Claim 6 A method of an RU according to claim 5, further comprising the step of receiving third information regarding a supported codebook down-selected based on the first information from the DU; wherein the second information includes an analog BF setting applied to a frequency band and a digital BF setting applied to a subband within the frequency band, and the second information further comprises a delay value and a JPTA (joint phase-time array) beam ID (identifier) ​​mapped to the phase value. Claim 7 A method of an RU according to claim 5, further comprising the step of receiving a control message from the DU, the control message including a first field indicating whether a digital beam ID (identifier) ​​is disabled and a second field indicating whether an analog beam ID is disabled; wherein the control message is received together with the second information, and the bit width of the control bit vector is 4 bits. Claim 8 A distributed unit (DU) of a communication system comprises: a transceiver; and a processor coupled to said transceiver; wherein the processor receives, from a radio unit (RU), first information regarding a supported hybrid beamforming (BF) setting, wherein the first information includes a number of analog ports, a number of digital ports, a number of analog ports per transceiver (TRX), and a supported codebook; generates a hybrid BF setting based on said supported codebook; and is configured to transmit, to said RU, second information regarding the hybrid BF setting, wherein the second information includes a control bit vector indicating a setting for a phase shifter of said RU; and wherein a phase value, an in-phase (I) value, and an orthogonal phase (Q) value are mapped to one value of said control bit vector. Claim 9 In claim 8, the processor is further configured to determine whether to down-select the supported codebook based on the first information, and if the DU determines to down-select the supported codebook, to transmit third information regarding the down-selected supported codebook to the RU, wherein the second information includes an analog BF setting applied to a frequency band and a digital BF setting applied to a subband within the frequency band. Claim 10 In claim 8, the processor is further configured to generate a control message comprising a first field indicating whether a digital beam ID (identifier) ​​is disabled and a second field indicating whether an analog beam ID is disabled, the control message is transmitted together with the second information, and the bit width of the control bit vector is 4 bits, characterized in that the DU. Claim 11 In claim 8, the DU further comprises the second information including a delay value and a JPTA (joint phase-time array) beam ID (identifier) ​​mapped to the phase value. Claim 12 A radio unit (RU) of a communication system comprises: a transceiver; and a processor coupled to said transceiver; wherein the processor is configured to transmit first information regarding a supported hybrid beamforming (BF) setting to a distributed unit (DU) - said first information includes a number of analog ports, a number of digital ports, a number of analog ports per transceiver (TRX), and a supported codebook; and to receive second information regarding a hybrid BF setting from said DU - said second information includes a control bit vector indicating a setting for a phase shifter of said RU; and wherein a phase value, an in-phase (I) value, and an orthogonal phase (Q) value are mapped to one value of said control bit vector. Claim 13 In claim 12, the processor is further configured to receive, from the DU, third information regarding a supported codebook down-selected based on the first information, wherein the second information includes an analog BF setting applied to a frequency band and a digital BF setting applied to a subband within the frequency band, and the second information further includes a delay value and a JPTA (joint phase-time array) beam ID (identifier) ​​mapped to the phase value, characterized in that the RU. Claim 14 In claim 12, the processor is further configured to receive a control message from the DU, the control message comprising a first field indicating whether a digital beam ID (identifier) ​​is disabled and a second field indicating whether an analog beam ID is disabled, the control message is received together with the second information, and the bit width of the control bit vector is 4 bits, characterized in that the RU.

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