Enhanced block floating point compression for open radio access network fronthaul

Abstract

A distributed unit (DU) signals a maximum IQ data bit width for downlink communications associated with a zone identifier (ID) to a radio unit (RU). The DU signals a per physical resource block (PRB) bit width parameter for downlink communications to the RU. The DU transmits the downlink communications based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB, and the RU receives the downlink communications based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB. For uplink communications, the DU transmits a first indication of a maximum IQ data bit width in a control plane message to the RU. The RU transmits a second indication of a per PRB bit width parameter for uplink communications to the DU. The RU transmits the uplink communications based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB, and the DU receives the uplink communications based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Indian Provisional Application No. 202041027773, filed on June 30, 2020, entitled “Enhanced Block Floating Point Compression for Open Radio Access Network Frontal,” which has been assigned to the assignee of this application and is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to communication systems, and more particularly to wireless communications related to outgoing routes in open radio access networks.

[0004] introduction

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunications services such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ multiple access technologies that enable communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, country, region, and even global levels. An example telecommunications standard is 5G New Radio (NR). 5G NR is part of the continuous evolution of mobile broadband, promulgated by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR can be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements to 5G NR technology. These improvements can also be applied to other multiple access technologies and telecommunications standards that adopt them.

[0007] Overview

[0008] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0009] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus for wireless communication at a distributed unit (DU) are provided. The apparatus signals a maximum IQ data bit-width for a downlink communication associated with a segment identifier (ID). The apparatus signals a bit-width parameter per physical resource block (PRB) for the downlink communication. The apparatus transmits, to a radio unit (RU), the downlink communication based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0010] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus for wireless communication at a RU are provided. The apparatus receives a first indication of a maximum IQ data bit-width for a downlink communication associated with a segment ID. The apparatus receives a second indication of a bit-width parameter per PRB for the downlink communication. The apparatus receives, from a DU, the downlink communication based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0011] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus for wireless communication at a DU are provided. The apparatus signals, in a control plane message, a maximum IQ data bit-width for an uplink communication to a RU. The apparatus receives a bit-width parameter per PRB for the uplink communication. The apparatus receives, from the RU, the uplink communication based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0012] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus for wireless communication at a RU are provided. The apparatus receives, from a DU, a first indication of a maximum IQ data bit-width for an uplink communication in a control plane message. The apparatus transmits a second indication of a bit-width parameter per PRB for the uplink communication. The apparatus transmits, to the DU, the uplink communication based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0013] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects can be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network according to some aspects.

[0016] Figure 2A 2B FIGs. 2C and 2D are diagrams illustrating various examples of a first 5G NR frame, DL channels within a 5G NR subframe, a second 5G NR frame, and UL channels within a 5G NR subframe, respectively, in accordance with some aspects.

[0017] Figure 3 FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network according to some aspects.

[0018] Figure 4 FIG. 4 is a diagram illustrating an example D-RAN architecture.

[0019] Figure 5 FIG. 5 is a diagram illustrating an example O-RAN architecture.

[0020] Figure 6 FIG. 6 is a diagram illustrating an example O-RAN logical architecture.

[0021] Figure 7 FIG. 7 is a diagram illustrating an example of a functional split between a central unit and a distributed unit in a network.

[0022] Figure 8 FIG. 8 is a diagram illustrating an example of an O-RAN fronthaul employing a functional split.

[0023] Figure 9 FIG. 9 is a diagram illustrating an example transport header for control plane messages.

[0024] Figure 10 FIG. 10 is a diagram illustrating an example of a control plane message.

[0025] Figure 11 FIG. 11 is a diagram illustrating an example of a user plane message.

[0026] Figure 12 FIG. 12 is a diagram illustrating an example of a compression method.

[0027] Figure 13 FIG. 13 is a diagram illustrating an example of signaling IQ data bit width. ​

[0028] Figure 14 FIG. 1 is a diagram illustrating an example of a user data compression parameter format.

[0029] Figure 15 FIG. 2 is a flowchart of a method of wireless communication.

[0030] Figure 16 FIG. 3 is a flowchart of a method of wireless communication.

[0031] Figure 17 FIG. 4 is a flowchart of a method of wireless communication.

[0032] Figure 18 FIG. 5 is a flowchart of a method of wireless communication.

[0033] DETAILED DESCRIPTION

[0034] The detailed description set forth below, in connection with the appended drawings and specifications, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein can be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without

[0035] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and design constraints imposed on the overall system.

[0036] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system can execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0037] Accordingly, in one or more example embodiments, the functions described can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that is suitable to store computer-executable instructions or data structures in a form that can be accessed by a computer.

[0038] Figure 1is a diagram illustrating an example of a wireless communications system and an access network 100. Base stations 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 through first backhaul links 132 (e.g., S I interface). Base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can interface with core network 190 through second backhaul links 184. In addition to other functions, the base stations 102 can perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 can communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface). The first backhaul links 132, the second backhaul links 184, and the third backhaul links 134 can be wired or wireless.

[0039] The base stations 102 can wirelessly communicate with the UEs 104. Each of the base stations 102 can provide communication coverage for a respective geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, a small cell 102' can have a coverage area 110' that overlaps with one or more macrocells 102. A network that includes both small cell and macrocells can be known as a heterogeneous network. A heterogeneous network can also include Home Evolved Node Bs (eNBs) (HeNBs), which can provide service to a restricted group known as a closed subscriber group (CSG). The communication links 120 between the base stations 102 and the UEs 104 can include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and / or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 can use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. These communication links can be through one or more carriers, where a carrier can be a set of

[0040] Certain UEs 104 can communicate using device-to-device (D2D) communication link 158. The D2D communication link 158 can use DL / UL WWAN spectrum. The D2D communication link 158 can use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication can be through a variety of wireless D2D communications systems, such as for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0041] The wireless communications system can further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 / AP 150 can perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

[0042] The small cell 102' can operate in a licensed and / or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' can employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102' employing NR in an unlicensed frequency spectrum can boost coverage and / or increase capacity for the access network.

[0043] Whether small cell 102' or a large cell (e.g., macro base station), the base station 102 can include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNB 180 can operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 can be referred to as a mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range from 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band are often called a millimeter wave. Near mmW can extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as the centimeter wave band. The frequency range bands include frequency range 1 (FR1) which includes bands below 7.225 GHz and frequency range 2 (FR2) which includes bands above 24.250 GHz. Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is above 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar naming complexity exists regarding FR2, which is often referred to (interchangeably) as a mmW band in documents and articles, despite being different from the EHF band identified by the International Telecommunications Union (ITU) as mmW frequencies.

[0044] With the above aspects in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like, if used herein, can broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like, if used herein, can broadly represent frequencies that can include mid-band frequencies, can be within FR2, or can be within an EHF band.

[0045] Communications using the mmW / near mmW radio frequency (RF) band (e.g., 3 GHz - 300 GHz) has extremely high path loss and a short range. A base station / UE can operate within one or more frequency range bands. The mmW base station 180 can utilize beamforming 182 with a UE 104 to compensate for the extremely high path loss and short range. The base station 180 and UE 104 can each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming.

[0046] The base station 180 can transmit a beamformed signal to the UE 104 in one or more transmit directions 182’. The UE 104 can receive the beamformed signal from the base station 180 in one or more receive directions 182”. The UE 104 can also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 can receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180 / UE 104 can perform beam training to determine the best receive and transmit directions for each of the base station 180 / UE 104. The transmit and receive directions for the base station 180 can or can not be the same. The transmit and receive directions for the UE 104 can or can not be the same.

[0047] The EPC 160 can include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 can be in communication with a home subscriber server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation as well as other functions. The PDN gateway 172 and the BM-SC 170 are connected to the IP services 176. The IP services 176 can include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 can provide functions for MBMS user service provisioning and

[0048] The core network 190 can include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 can be in communication with a unified data management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred

[0049] A base station can include and / or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. A base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kiosk, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functional device. Some of the UEs 104 can be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicle, heart monitor, etc.). The UE 104 can also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0050] In some examples, the base station 102 / 180 can be a radio unit (RU) connected to a core network 190 or EPC 160 via a distributed unit (DU) 103. The RU and the DU can communicate frequency domain baseband samples, referred to as IQ data. As Figure 1 As illustrated in FIG. 3, the DU 103 can include a bit width component configured to signal a maximum IQ data bit width for downlink communications associated with a zone ID and signal a per-PRB bit width parameter for downlink communications, as described herein. The DU 103 can transmit a downlink communication to a RU (e.g., base station 102 / 180) based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB. The RU can include a bit width component 199 configured to receive a first indication of the maximum IQ data bit width for downlink communications associated with a zone ID and a second indication of a per-PRB bit width parameter for downlink communications. The RU can then receive a downlink communication from the DU 103 based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB.

[0051] In some examples, the bit width component 198 can be configured to signal, in a control plane message, a maximum IQ data bit width for uplink communications to an RU (e.g., base station 102 / 180) and receive, from the RU, a bit width parameter per PRB for uplink communications. The DU 103 can then receive uplink communications from the RU based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB. Similarly, the bit width component 199 can be configured to receive, in a control plane message, a first indication of a maximum IQ data bit width for uplink communications from the DU 103 and transmit a second indication of a bit width parameter per PRB for uplink communications.

[0052] Figure 2A FIG. 200 is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. Figure 2B FIG. 230 is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. Figure 2C FIG. 250 is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. Figure 2D FIG. 280 is a diagram 280 illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure can be frequency division duplex (FDD), where for a particular subcarrier set (carrier system bandwidth), subframes within that subcarrier set are dedicated to DL or UL; or time division duplex (TDD), where for a particular subcarrier set (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL. In the examples provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL) and subframe 3 is configured with slot format 34 (mostly UL), where D is DL, U is UL, and F is flexible for use between DL / UL. While subframes 3, 4 are shown with slot formats 34, 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. A UE is configured with a slot format (dynamically through DL control information (DCI), or semi- statically / statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the following description applies also to 5G NR frame structures that are TDD. Figure 2A 、 2C In the examples provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL) and subframe 3 is configured with slot format 34 (mostly UL), where D is DL, U is UL, and F is flexible for use between DL / UL. While subframes 3, 4 are shown with slot formats 34, 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. A UE is configured with a slot format (dynamically through DL control information (DCI), or semi- statically / statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the following description applies also to 5G NR frame structures that are TDD.

[0053] Other wireless communication technologies can have different frame structures and / or different channels. A frame (10 ms) can be divided into 10 equally sized subframes (1 ms). Each subframe can include one or more time slots. A subframe can also include mini-slots, which can contain 7, 4, or 2 symbols. Each time slot can include 7 or 14 symbols depending on the slot configuration. For a slot configuration 0, each time slot can include 14 symbols, and for a slot configuration 1, each time slot can include 7 symbols. The symbols on the DL can be CP-OFDM (CP-OFDM) symbols. The symbols on the UL can be CP-OFDM symbols for high throughput operation (for a simplified architecture) or DFT-s-OFDM symbols (also known as SC-FDMA symbols) for a power limited scenario; limited to single stream transmission. The number of time slots within a subframe is based on the slot configuration and the numerology. For the slot configuration 0, different numerologies m of 0 to 4 allow 1, 2, 4, 8, and 16 time slots per subframe, respectively. For the slot configuration 1, different numerologies of 0 to 2 allow 2, 4, and 8 time slots per subframe, respectively. Accordingly, for the slot configuration 0 and numerology m, there are 14 symbols per time slot and 2 μ time slots per subframe. The subcarrier spacing and symbol length / duration are a function of the numerology. The subcarrier spacing can equal 2 μ *15 kHz, where m is the numerology of 0 to 4. As such, numerology m = 0 has a subcarrier spacing of 15 kHz, while numerology m = 4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A to 2D An example of the slot configuration 0 with 14 symbols per time slot and the numerology m = 2 with 4 time slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 ps. Within a frame set, there can be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP can have a particular numerology.

[0054] A resource grid can be used to represent the frame structure. Each time slot includes resource blocks (RBs) (also referred to as physical RBs (PRBs)) that extend for the full duration of the time slot in the frequency domain. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0055] As explained in Figure 2A , some of the REs carry reference (pilot) signals (RS) for the UE. The RS can include demodulation RS (DM-RS) (indicated as R x(where 100x is the port number, but other DM-RS configurations are possible) and Channel State Information Reference Signal (CSI-RS). RS may also include Beam Measurement RS (BRS), Beam Refinement RS (BRRS), and Phase Tracking RS (PT-RS).

[0056] Figure 2B Examples of various DL channels within a subframe of a frame are explained. The Physical Downlink Control Channel (PDCCH) carries the DCI within one or more Control Channel Elements (CCEs), each CCE comprising 9 RE Groups (REGs), each REG comprising 4 consecutive REs in OFDM symbols. The PDCCH within a BWP can be referred to as a Control Resource Set (CORESET). Additional BWPs can be located at higher and / or lower frequencies spanning the channel bandwidth. The Primary Synchronization Signal (PSS) is located within symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identity. The Secondary Synchronization Signal (SSS) is located within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the Physical Layer Cell Identity Group Number and radio frame timing. Based on the Physical Layer Identity and Physical Layer Cell Identity Group Number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The Physical Broadcast Channel (PBCH), carrying the Master Information Block (MIB), can logically group with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also known as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as the System Information Block (SIB)), and paging messages.

[0057] As in Figure 2C As explained, some REs carry DM-RS for channel estimation at the base station (indicated as R for a specific configuration, but other DM-RS configurations are possible). The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and DM-RS for the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the first or first two symbols of the PUSCH. The PUCCH DM-RS can be transmitted in different configurations depending on whether a short or long PUCCH is being transmitted and depending on the specific PUCCH format used. The UE can transmit a probe reference signal (SRS). The SRS can be transmitted in the last symbol of a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0058] Figure 2D An example of various UL channels within a subframe of a TDD frame is illustrated. The PUCCH can be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) ACK / NACK feedback. The PUSCH carries data, and can additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0059] Figure 3 is a block diagram of the components of base station 310 and UE 350, which are in communication over access network 320. In the DL, IP packets from the core network 160 can be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter radio access technology (RAT) mobility, and measurement configuration

[0060] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, can include error detection on the transport channels, forward error correction (FEC) coding / decoding of the transport channels, interleaving, rate matching, mapping to physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be split into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 can be used to determine the coding and modulation schemes, as well as for spatial processing. The channel estimate can be derived from a reference signal and / or channel condition feedback transmitted by the UE 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier with a respective spatial stream for transmission.

[0061] At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. The soft decisions can be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0062] The controller / processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 can be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0063] Similar to the functionality described in connection with the DL transmission by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0064] Channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310 can be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 can be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX can modulate an RF carrier with a respective spatial stream for transmission.

[0065] The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0066] The controller / processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 can be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller / processor 375 can be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0067] A base station can be configured with a Distributed Radio Access Network (D-RAN) architecture. Figure 4 FIG. 4 is a diagram 400 illustrating an example D-RAN architecture. In the D-RAN architecture, both a baseband unit (BBU) 402 and a remote radio unit (RRU) 404 (such as an antenna and RF front end) can be deployed together in each base station 406. The RRU 404 can be used in telecommunications as an interface to communicate with UEs 408, such that the UEs 408 can be able to communicate with a core network (e.g., EPC 410) through the RRU 404. The RRU 404 can communicate with the BBU 402 via optical fiber (e.g., optical fiber) and Ethernet protocols, and the BBU 402 can communicate with the core network via a backhaul (BH) network. The hardware and / or software for the BBU 402 and the RRU 404 within each base station 406 can be proprietary and managed by different vendors (e.g., telecommunication companies), and the interfaces for accessing the BBU 402 and the RRU 404 can also be proprietary by the vendors. As such, under the D-RAN architecture, the BBU 402 and / or the RRU 404 from different vendors can not be compatible with each other, where a network operator who wants to set up the base station 406 can need to purchase both the RRU 404 and the BBU 402 from the same vendor. Thus, the D-RAN architecture can limit interoperability between different network equipment.

[0068] The Open Radio Access Network (O-RAN) reference architecture is designed to enable next generation RAN infrastructure. The O-RAN architecture is the foundation for building a virtualized RAN as envisioned by global operators on open hardware with embedded AI-driven radio control, under the support of smart and open principles. The architecture is based on well-defined standardized interfaces to enable an open, interoperable supply chain ecosystem, fully supporting and complementing the standards facilitated by 3GPP and other industry standard organizations. To enhance and achieve interoperability between baseband processing equipment and radio equipment from different vendors, some networks can employ the O-RAN architecture.

[0069] Figure 5FIG. 500 is a diagram 500 that illustrates an example of an O-RAN architecture. Under the O-RAN architecture, the hardware portion of the network (such as the RRUs 504) can be decoupled from the software portion of the network (such as the BBUs 502). For example, multiple BBUs 502 corresponding to different RRUs 504 can be allocated at a centralized location (e.g., a BBU station 512), where each BBU 502 can be connected to its RRU 504 via an Ethernet connection. The multiple BBUs 502 within the BBU station 512 can run on the same software, which can be proprietary software. However, the software can be designed to be compatible with and operable by general-purpose (e.g., off-the-shelf) hardware, such as a commercial off-the-shelf (COTS) server. Using this approach, the BBUs 502 and the RRUs 504 can be designed to have open interfaces so that an RRU 504 from one vendor can interact with a BBU 502 from another vendor, enabling interoperability of radio equipment (e.g., RRUs, BBUs) from different vendors. For example, a network operator can purchase BBUs 502 from a particular vendor and the BBUs 502 can work with RRUs 504 from another vendor, as long as the correct interfaces are configured. In addition, the network operator can also run different types of software (e.g., BBUs 502) on the hardware, such as by purchasing multiple licenses for the software. This can reduce the cost of setting up the hardware for the network for the network operator and enable rapid scaling of the network. In other words, O-RAN can be characterized as an emerging form of virtualized network architecture built on general-purpose, off-the-shelf hardware. The architecture can allow for different combinations of hardware and software, and can be easily integrated and upgraded via software.

[0070] Under the O-RAN architecture, the functions within the BBU 502 can be further decoupled, where the network operator can have the option to purchase specific functions for specific operations. Figure 6is a diagram 600 illustrating an example O-RAN logical architecture, which can include a plurality of network functions and components, such as a service management and orchestration framework, a near-real-time RAN intelligent controller (RIC), a base station (e.g., an O-eNB), a central unit - control plane (CU-CP), a central unit - user plane (CU-UP), a distributed unit (DU) 602 (e.g., an O-RAN distributed unit (O-DU)), a radio unit (RU) 604 (e.g., an O-RAN radio unit (O-RU)), and / or a cloud unit, etc. O-RAN fronthaul (O-RAN FH) corresponds to an open interface between the O-DU and the O-RU to achieve interoperability goals. Each of these functions or components can be operated by different vendors. For example, a first vendor can provide the base station, a second vendor can provide the CU-UP, and a third vendor can provide the CU-CP, etc. The various functions and / or components can communicate with each other over specific interfaces, such as the CU-CP and CU-UP can communicate with the near-real-time RIC via an E2 interface, the service management and orchestration framework can communicate with the DU and RU via an O1 interface, etc. The DU 602 can communicate with the RU 604 via a fronthaul interface (e.g., open fronthaul CU-User plane, open fronthaul M-plane, etc.), and there can be a functional split between the DU 602 and the RU 604, where each of the DU 602 and the RU 604 can be configured to handle different network functions within the O-RAN (e.g., PHY layer processing).

[0071] Figure 7 is a diagram 700 illustrating an example of a functional split between a central unit (CU) 706 and a DU 702 in a network. The CU 706 can be a logical node that includes base station functions, such as transfer of user data, mobility control, session management, etc., except for functions unique to the DU 702. The CU 706 can be connected to a core network (e.g., an EPC 708) via a backhaul (BH) interface, and can control operation of multiple DUs 702 over a midhaul (e.g., MH or Fl) interface. The DU 702 can be a logical node that includes a subset of base station functions, where its operation can be controlled by the CU 706. Under the O-RAN architecture, the DU 702 can be further split or separated into the DU 602 and the RU 604, such as described in connection with Figure 5 and 6 described, where the DU 602 can communicate with the RU 604 via a FH interface. Network functionality, such as functionality associated with PDCP, RLC, MAC, PHY network layers, etc., can be split among the CU 706, the DU 702, and the RU 704, such as based on Figure 7Options 1-8. For example, functionality can be split on Option 2 and Option 7 (e.g., split Option 7-2x, Option 7.2 split, etc.) such that the CU 706 can be responsible for handling functionality associated with RRC and PDCP layers, the DU 702 can be responsible for handling functionality associated with RLC, MAC, and HI-PHY (e.g., PHY-High) layers, and the RU 704 can be responsible for handling functionality associated with LO-PHY (e.g., PHY-Low) and RF layers, and so on.

[0072] Figure 8 is a diagram 800 illustrating an example of an O-RAN fronthaul employing functionality split at Option 2 and Option 7 between the CU 806, the DU 802, and the RU 804. The PHY-High layers 808 within the DU 802 can include functions such as scrambling, modulation, layer mapping, precoding (e.g., Category A), resource element mapping, and / or IQ compression, and so on. The PHY-Low and RF layers 810 within the DU 802 can include functions such as IQ decompression, precoding (e.g., Category B), digital beamforming, iFFT and CP addition, digital-to-analog conversion, and / or analog beamforming, and so on. In O-RAN, there can be two types of precoding for RUs depending on where precoding occurs, Category A (e.g., CAT A) and Category B (e.g., CAT B). For example, for Category A, precoding can occur at the DU 802 and precoding can not be supported at the RU 804, and the RU 804 can be referred to as a non-precoded O-RAN RU. On the other hand, for Category B, precoding, precoding in the radio, is supported at the RU 804, and the RU 804 can be referred to as a precoded O-RAN RU. Category B can also support modulation compression.

[0073] When data flows from a DU (e.g., O-DU 602, 702, 802) to an RU (e.g., O-RU 604, 704, 804), the data can flow through a user plane (U-plane), a control plane (C-plane), and a synchronization plane (S-plane). The user plane can be responsible for conveying data from the DU to the RU. For example, user plane messages can carry DL frequency domain IQ data (e.g., downlink user data (PDSCH), control channel data (PDCCH), etc.) and / or UL frequency domain IQ data (e.g., uplink user data (PUSCH), control channel data (PUCCH), etc.). Control plane messages can include control information such as scheduling commands and beamforming commands that can indicate how data conveyed in the user plane is to be interpreted. As such, control plane messages can correspond to user plane messages. Both control plane messages and user plane messages can be carried in a payload section of a transmission via an Ethernet connection.

[0074] The control plane messages can employ a two-layer header approach, where one header can be a transport header and the other header can be an application header. Figure 9 FIG. 900 is a diagram 900 illustrating an example transport header for control plane messages. The transport header can indicate a type of message and interface (e.g., ecpriMessage), a payload length (e.g., ecpriPayload), a control plane message source and destination identifier (e.g., ecpriRtcid) or a user plane message source and destination identifier (e.g., ecpriPcid), and / or a message sequence number (e.g., ecpriSeqid), etc. Figure 10is a diagram 1000 illustrating an example of a control plane message from a DU to a RU including a transport header 1002 (e.g., an enhanced common public radio interface (eCPRI) transport header) and an application header 1004. The application header 1004 can include necessary fields for control and synchronization. For example, the application header 1004 can include various fields such as data direction, payload version, filter index, frame ID, subframe ID, slot ID, starting symbol ID, segment ID, segment number, segment type, user plane compression header (udCompHdr) header, etc. The data direction field can be used to indicate whether the message is for downlink or uplink data. The payload version field can be used to indicate the structure or architecture version of the payload. The filter index field can be used to select or change a channel filter. The slot and starting symbol ID fields can be used to indicate which symbol(s) within a slot are referenced by the header (e.g., the start of the symbol in the slot). The segment number field can be used to indicate how many segments are following the application header (e.g., after the application header) (i.e., how many segments are defined in the current control plane message). Control information within the control plane message can be conveyed in the form of segments. For example, each segment in the control plane message can define the characteristics of user plane data to be delivered or received from a beam with one mode ID. The segment type field can be used to define the type of segment such as based on Table 1 below.

[0075]

[0076]

[0077] Table 1 - Examples of Segment Types

[0078] The user data compression header field in the control plane message can be used for uplink and can have two component parts. One component part can be the compression method (e.g., udCompMeth) and the other component part can be the bit width. The compression method component can indicate the compression method used for the user plane message associated with the control plane message and the bit width component can indicate the bit width of each IQ data after compression. Figure 12 is a diagram 1200 illustrating an example of a compression method.

[0079] After the application header 1004 is the section ID section, which can include a section ID field that can be used to assign an ID to the frequency and time resources (e.g., resources used to transmit data in a user plane message). There can be more than one section ID defined in the section ID section, and there can be additional parameters and configurations associated with each section ID. The section ID configured in the control plane message can be used by the DU or RU to associate the user plane message and the corresponding control plane message. For example, after the section ID and its associated parameters are defined in the control plane message, the same section ID can be assigned to the user plane message. Thereby, the user plane message can use the section ID to correlate to the control plane message, and can apply the parameters and configurations associated with the section ID to the data (e.g., IQ data) it transmits. The control plane message can include multiple section IDs for multiple frequency resources, where there can be a one-to-one mapping of configurations for user plane IQ data. The associated parameters and configurations can include a start PRB field (e.g., startPrbc) and a PRB number field (e.g., numPrbc), which can be used to indicate where the configuration starts and the length of the configuration. In other words, the section ID section of the control plane message can be used to create a section(s) that defines the frequency resources for the corresponding IQ data in the corresponding user plane message. The control plane message can further include a beam identifier field after the section ID section to identify the beam(s) to be used to transmit the user plane message.

[0080] Figure 11 FIG. 1100 is a diagram 1100 illustrating an example of a user plane message, where the user plane message can have a similar transport header 1102 and application header 1104 as the control plane message, and can be followed by a section ID header received in the control plane message, such as described in connection with Figure 10 For example, the IQ data presented in the user plane message can use the parameters and configurations (e.g., startPrbc, numPrbc, etc.) associated with the section ID assigned from the control plane message. The user plane message can also include a user data compression header (e.g., udCompHdr), followed by a bit width, and a user data compression parameter (udCompParam) field. The user data compression header in the user plane message can be used for downlink transmission, and can indicate the compression method used for the user plane message and the bit width of the compressed IQ data.

[0081] The payload section of the user plane message (e.g., eCPRI payload) can be used to convey the IQ samples (e.g., iSample / qSample sequences) of the OFDM signal in the frequency domain with the application of IQ compression and IQ compression information (e.g., udCompHdr). This information can be conveyed along with the time and / or frequency resource information applied to the transmission and reception of the IQ sample sequences. The user data compression parameter (udCompParam) field can be used to indicate the compression scheme applied and the number of bits in the compressed IQ samples. The IQ compression can be performed using common IQ compression parameters for each PRB (e.g., 12 IQ samples). For example, when block floating point is used for compression, the IQ compression parameters and the IQ sample sequences can represent the exponent and mantissa in floating point form. There can be multiple user data compression parameters in the section of the user plane message, such as per PRB or a number of resource elements at a time (e.g., 12 REs). The value (e.g., size) of the user data compression parameter can vary depending on the compression method.

[0082] In O-RAN downlink, the bit-width of the user plane IQ data can be sent or indicated once per section in the user data compression header parameter of the user plane message (e.g., after udCompHdr). For uplink, the bit-width of the IQ data can be sent or indicated in the control plane message, where the bit-width can be constant for all sections defined under the control plane message. As such, in downlink, the bit-width signaling granularity can be per data section, while in uplink, the bit-width signaling can be per control plane message. In other words, in downlink, the bit-width signaling occurs once per data section, while in uplink, the bit-width signaling occurs once per control plane message. If the bit-width representing the actual signal is less than the configured bit-width in the data section (e.g., for downlink) or control plane message (e.g., for uplink), this can result in significant redundant information to be sent over the O-RAN FH. For example, the bit-width in the data section for downlink or in the control plane message for uplink can be configured to be 12 bits, but the actual bit-width needed can be 3 bits, which can result in 9 bits not being used or redundant. Further, for uplink, the DU can be assigned to determine the bit-width for the uplink data. Since the DU can not have information about the size of the uplink data (e.g., the number of bits sufficient to represent the uplink data), the DU can overestimate the bits needed to send the IQ data to avoid loss.

[0083] Aspects presented herein can provide better compression granularity for uplink and downlink transmission of IQ data between a DU and a RU. Aspects presented herein can enhance estimation / reporting of bit width size by reducing the signaling granularity of the bit width parameter to per-PRB instead of per-segment or per-control plane message for downlink and / or uplink. This signaling granularity can apply to block floating point (BFP) compression, which can be a common compression method used by O-RAN.

[0084] In an aspect, for downlink, a user data compression header (e.g., udCompHdr) in a user plane message can signal a maximum IQ data bit width “R” (e.g., R is a value) using a new or existing parameter, such as a user data IQ width (e.g., udIqWidth) parameter. The maximum IQ data bit width can provide a default bit width value for a PRB, and it can be associated with a segment ID, such as described in connection with Figure 10 and 11 As the user data compression parameter (e.g., udCompParam) can be signaled once per PRB (e.g., per 12 REs), the MSB 4-bit field in the user data compression parameter can be used to signal the actual bit width “X” (e.g., per PRB) used in the PRB, such that the bit width for IQ data can be signaled per PRB instead of per segment. Each PRB within a user plane message can indicate the actual bit width within that PRB, and the PRB can be transmitted based on the actual bit width (e.g., X) instead of the maximum / default bit width (e.g., R). For example, a user plane message can determine a maximum IQ data bit width “R” to be 12 bits. However, if the actual IQ data bit width is 4 bits (e.g., X = 4), the MSB 4-bit field in the user data compression parameter (e.g., udCompParam) can indicate that only 4 bits are used in that PRB. After this MSB 4-bit field is signaled, the PRB can use 4 bits instead of 12 bits for the bit width, saving 8 bits of resources.

[0085] Some RUs can not support the per-PRB bit width configuration described above, which can occur and can be known by the DU as part of the capability exchange with the RU via the M-plane. In this case, the RU can be configured to ignore the MSB 4-bit field in the user data compression parameter of the user plane message. In other words, the RU can continue to use the default bit width value (e.g., R) for the PRB. In some scenarios, the RU can not have support for certain bit width values. As such, the value of X can also be configured based on the bit width values supported by the RU and known by the DU as part of the capability exchange between the DU and the RU via the M-plane message. If X does not have a suitable value, the RU can use the maximum (e.g., default) R bits for the bit width.

[0086] Figure 13 is a diagram 1300 illustrating an example of using a MSB 4-bit field (e.g., udIqWidth) to signal an IQ data bit width X. For example, when the MSB 4-bit field indicates 0000, I and Q in the IQ data can each be 16 bits wide; when the MSB 4-bit field indicates 0001, I and Q in the IQ data can each be 1 bit wide; when the MSB 4-bit field indicates 1111, I and Q in the IQ data can each be 15 bits wide, and so on.

[0087] In another aspect, for uplink, an existing parameter such as udIqWidth in the user data compression header (e.g., in a control plane message) can be used for the maximum IQ bit width “R” for all segments signaled with control plane messages. Similarly, the MSB 4-bits in the user data compression parameter (e.g., udCompParam) signaled per PRB (which can be reserved for BFP compression) can be used to signal the actual bit width “X” used in the PRB, which can be similar to the bit width in the user plane message. For DU(s) that can not have support for per-PRB bit width granularity configuration (which can be known by the RU as part of the capability exchange via the M-plane), the MSB 4-bit field in the user data compression parameter can be ignored. In some scenarios, the DU can not support certain bit width values. As such, the value of X can also be configured based on the bit width values supported by the DU and known by the RU as part of the capability exchange via the M-plane message. If X does not have a suitable value, the DU can use the maximum (e.g., default) R bits for the bit width.

[0088] In another aspect, additional compression methods can also be provided or defined for the RU and the DU and can be signaled in the user data compression header, such as shown in Figure 12 In one example, the user data compression parameter (udCompParam) can be configured to signal the actual bit width. Figure 14 is a diagram 1400 illustrating an example of a user data compression parameter format that can be used to signal the actual bit width of the IQ data. For example, an additional compression method (e.g., udCompMeth = 0111b) can be added and used to define the MSB 4-bits within the user data compression parameter to indicate the actual bit width of the IQ data for a PRB, and the least significant bit (LSB) 4-bits can be used to indicate the exponent for the BFP compression.

[0089] Figure 15is a flowchart 1500 of a method of wireless communication. The method can be performed by a distributed unit (e.g., the DU 602, 702, 802). Optional aspects are illustrated with a dashed line. The method can enable a DU to provide better compression granularity by signaling an IQ data bitwidth per PRB

[0090] At 1502, the DU can signal a maximum IQ data bitwidth for downlink communications associated with a segment ID, such as described in connection with Figure 12 and 13 The maximum IQ data bitwidth can be signaled in a user plane compression header (udCompHdr).

[0091] At 1504, the DU can signal a bitwidth parameter per PRB for downlink communications, such as described in connection with Figure 12 and 13 The bitwidth parameter per PRB can be signaled in a user plane compression parameter (udCompParam).

[0092] At 1506, the DU can transmit downlink communications to a RU based on at least one of the maximum IQ data bitwidth or the bitwidth parameter for a PRB, such as described in connection with Figure 12 and 13 In one aspect, the DU can transmit downlink communications based on the maximum IQ data bitwidth for a RU that does not support per-PRB bitwidth granularity. For example, the DU can receive capability signaling from the RU prior to transmitting the downlink communications, where the capability signaling can indicate that the RU does not support PRB bitwidth granularity. In another aspect, the DU can transmit downlink communications based on the bitwidth parameter for a PRB for a RU that supports per-PRB bitwidth granularity. For example, the DU can receive capability signaling from the RU prior to transmitting the downlink communications, where the capability signaling indicates that the RU supports PRB bitwidth granularity. In another aspect, the DU can receive capability signaling from the RU prior to transmitting the downlink communications, where the capability signaling indicates a bitwidth size supported by the RU, where the bitwidth parameter for a PRB is based on the bitwidth size supported by the RU.

[0093] Figure 16 is a flowchart 1600 of a method of wireless communication. The method can be performed by a radio unit (e.g., the RU 604, 704, 804). Optional aspects are illustrated with a dashed line. The method can enable a RU to provide better compression granularity by signaling a bitwidth of IQ data per PRB.

[0094] At 1602, the RU can receive a first indication of a maximum IQ data bitwidth for downlink communications associated with a segment ID, such as described in connection with Figure 12 and13 The first indication of the maximum IQ data bit width can be received in a user plane compression header (udCompHdr).

[0095] At 1604, the RU can receive a second indication of a bit width parameter per PRB for downlink communications, such as described in connection with Figure 12 and 13 The second indication of the bit width parameter per PRB is received in a user plane compression parameter (udCompParam).

[0096] At 1606, the RU can receive downlink communications from the DU based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB, such as described in connection with Figure 12 and 13 In an aspect, when the RU does not support per PRB bit width granularity, the RU can receive the downlink communications based on the maximum IQ data bit width. The RU can transmit capability signaling to the DU prior to receiving the downlink communications, where the capability signaling can indicate that the RU does not support PRB bit width granularity. In another aspect, when the RU supports per PRB bit width granularity, the RU can receive the downlink communications based on the bit width parameter for the PRB. The RU can transmit capability signaling to the DU prior to receiving the downlink communications, where the capability signaling can indicate that the RU supports PRB bit width granularity. In another aspect, the RU can transmit capability signaling to the DU prior to receiving the downlink communications, where the capability signaling indicates a bit width size supported by the RU, and the bit width parameter for the PRB can be based on the bit width size supported by the RU.

[0097] Figure 17 FIG. 17 is a flow diagram 1700 of a method of wireless communication. The method can be performed by a distributed unit (e.g., the DU 602, 702, 802). The optional aspects are illustrated with dashed lines. The method can enable the DU to provide better compression granularity by signaling a bit width of IQ data per PRB.

[0098] At 1702, the DU can signal a maximum IQ data bit width for uplink communications to the RU in a control plane message, such as described in connection with Figure 12 and 13 For example, the maximum IQ data bit width can be signaled in a user plane compression header (udCompHdr).

[0099] At 1704, the DU can receive a bit width parameter per PRB for uplink communications, such as described in connection with Figure 12 and 13 For example, the bit width parameter per PRB can be received in a user plane compression parameter (udCompParam).

[0100] At 1706, the DU can receive the uplink communication from the RU based on at least one of a maximum IQ data bit width or a bit width parameter for PRBs, such as described in connection with Figure 12 and 13 At 1706, the DU can receive the uplink communication from the RU based on at least one of a maximum IQ data bit width or a bit width parameter for PRBs, such as described in connection with

[0101] Figure 18 is a flow diagram of a method of wireless communication 1800. The method can be performed by a radio unit (e.g., the RU 604, 704, 804). Optional aspects are illustrated with a dashed line. The method can enable the RU to provide better compression granularity by signaling a bit width of IQ data per PRB.

[0102] At 1802, the RU can receive, from a DU, a first indication of a maximum IQ data bit width for uplink communication in a control plane message, such as described in connection with Figure 12 and 13 In one example, the first indication of the maximum IQ data bit width can be received in a user plane compression header (udCompHdr).

[0103] At 1804, the RU can transmit a second indication of a bit width parameter per PRB for the uplink communication, such as described in connection with Figure 12 and 13 In one example, the second indication of the bit width parameter per PRB is transmitted in a user plane compression parameter (udCompParam).

[0104] At 1806, the RU can transmit the uplink communication to the DU based on at least one of the maximum IQ data bit width or the bit width parameter for PRBs, such as described in connection with Figure 12 and 13Described. In an aspect, uplink communications can be transmitted for a DU that does not support per-PRB bit-width granularity based on a maximum IQ data bit-width. The RU can receive, from the DU prior to transmitting the uplink communications, capability signaling indicating that the DU does not support PRB bit-width granularity. In another aspect, uplink communications can be transmitted for a DU that supports per-PRB bit-width granularity based on a bit-width parameter for a PRB. The RU can receive, from the DU prior to transmitting the uplink communications, capability signaling indicating that the DU supports PRB bit-width granularity. In another aspect, the RU can receive, from the DU prior to transmitting the uplink communications, capability signaling indicating a bit-width size supported by the DU, where the bit-width parameter for a PRB is based on the bit-width size supported by the DU.

[0105] The following examples illustrate additional aspects and are not intended to be limiting in any way.

[0106] Aspect 1 is a method of wireless communication at a DU, the method comprising: signaling a maximum IQ data bit-width for a downlink communication associated with a segment ID; signaling a bit-width parameter per PRB for the downlink communication; and transmitting the downlink communication to a RU based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0107] In Aspect 2, the method of Aspect 1 further includes that the maximum IQ data bit-width is signaled in a user plane compression header (udCompHdr), and where the bit-width parameter per the PRB is signaled in a user plane compression parameter (udCompParam).

[0108] In Aspect 3, the method of Aspect 1 or Aspect 2 further includes that the downlink communication is transmitted for a RU that does not support per-PRB bit-width granularity based on the maximum IQ data bit-width.

[0109] In Aspect 4, the method of any of Aspects 1-3 further includes receiving, from the RU prior to transmitting the downlink communication, capability signaling indicating that the RU does not support the PRB bit-width granularity.

[0110] In Aspect 5, the method of any of Aspects 1-4 further includes that the downlink communication is transmitted for the RU that supports per-PRB bit-width granularity based on the bit-width parameter for the PRB.

[0111] In Aspect 6, the method of any of Aspects 1-5 further includes receiving, from the RU prior to transmitting the downlink communication, capability signaling indicating that the RU supports the PRB bit-width granularity.

[0112] In Aspect 7, the method of any of Aspects 1-6 further includes receiving capability signaling from the RU prior to transmitting the downlink communication, wherein the capability signaling indicates a bitwidth size supported by the RU, wherein the bitwidth parameter for the PRB is based on the bitwidth size supported by the RU.

[0113] Aspect 8 is an apparatus for wireless communication at a DU, comprising: means for signaling a maximum IQ data bitwidth for a downlink communication associated with a zone ID; means for signaling a bitwidth parameter per PRB for the downlink communication; and means for transmitting the downlink communication to a RU based on at least one of the maximum IQ data bitwidth or the bitwidth parameter for the PRB.

[0114] In Aspect 9, the method of Aspect 8 further includes means for performing the method of any of Aspects 2-7.

[0115] Aspect 10 is an apparatus for wireless communication at a DU, comprising: a memory; and at least one processor coupled to the memory, the memory and the at least one processor configured to perform the method of Aspects 1-7.

[0116] Example 11 is a computer-readable medium storing computer executable code for wireless communication at a DU, the code when executed by a processor causes the processor to perform the method of any of Aspects 1-7.

[0117] Aspect 12 is a method of wireless communication at a RU, comprising: receiving a first indication of a maximum IQ data bitwidth for a downlink communication associated with a zone ID; receiving a second indication of a bitwidth parameter per PRB for the downlink communication; and receiving the downlink communication from a DU based on at least one of the maximum IQ data bitwidth or the bitwidth parameter for the PRB.

[0118] In Aspect 13, the method of Aspect 12 further includes the first indication of the maximum IQ data bitwidth is received in a user plane compression header (udCompHdr), and wherein the second indication of the bitwidth parameter per the PRB is received in a user plane compression parameter (udCompParam).

[0119] In Aspect 14, the method of Aspect 12 or Aspect 13 further includes the RU does not support per PRB bitwidth granularity and the downlink communication is received based on the maximum IQ data bitwidth.

[0120] In aspect 15, the method of any of aspects 12-14 further includes transmitting capability signaling to the DU prior to receiving the downlink communication, wherein the capability signaling indicates that the RU does not support the PRB bitwidth granularity.

[0121] In aspect 16, the method of any of aspects 12-15 further includes that the RU supports per-PRB bitwidth granularity and the downlink communication is received based on the bitwidth parameter for the PRB.

[0122] In aspect 17, the method of any of aspects 12-16 further includes transmitting capability signaling to the DU prior to transmitting the downlink communication, wherein the capability signaling indicates that the RU supports the PRB bitwidth granularity.

[0123] In aspect 18, the method of any of aspects 12-17 further includes transmitting capability signaling to the DU prior to transmitting the downlink communication, wherein the capability signaling indicates the bitwidth size supported by the RU, wherein the bitwidth parameter for the PRB is based on the bitwidth size supported by the RU.

[0124] Aspect 19 is an apparatus for wireless communication at a RU, comprising: means for receiving a first indication of a maximum IQ data bitwidth for a downlink communication associated with a segment ID; means for receiving a second indication of a bitwidth parameter per PRB for the downlink communication; and means for receiving the downlink communication from a DU based on at least one of the maximum IQ data bitwidth or the bitwidth parameter for the PRB.

[0125] In aspect 20, the method of aspect 19 further includes means for performing the method of any of aspects 13-18.

[0126] Aspect 21 is an apparatus for wireless communication at a RU, comprising: a memory; and at least one processor coupled to the memory, the memory and the at least one processor configured to perform the method of aspects 12-18.

[0127] Aspect 22 is a computer-readable medium storing computer executable code for wireless communication at a RU, the code when executed by a processor causes the processor to perform the method of any of aspects 12-18.

[0128] Aspect 23 is a method of wireless communication at a DU, comprising: signaling, to a RU, a maximum IQ data bit-width for an uplink communication in a control plane message; receiving a bit-width parameter per PRB for the uplink communication; and receiving the uplink communication from the RU based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0129] In Aspect 24, the method of Aspect 23 further includes that the maximum IQ data bit-width is signaled in a user plane compression header (udCompHdr), and wherein the bit-width parameter per the PRB is received in a user plane compression parameter (udCompParam).

[0130] In Aspect 25, the method of Aspect 23 or Aspect 24 further includes that the DU does not support per-PRB bit-width granularity and the uplink communication is received based on the maximum IQ data bit-width.

[0131] In Aspect 26, the method of any of Aspects 23-25 further includes transmitting capability signaling to the RU prior to receiving the uplink communication, wherein the capability signaling indicates that the DU does not support the PRB bit-width granularity.

[0132] In Aspect 27, the method of any of Aspects 23-26 further includes that the DU supports per-PRB bit-width granularity and the uplink communication is received based on the bit-width parameter for the PRB.

[0133] In Aspect 28, the method of any of Aspects 23-27 further includes transmitting capability signaling to the RU prior to receiving the uplink communication, wherein the capability signaling indicates that the DU supports the PRB bit-width granularity.

[0134] In Aspect 29, the method of any of Aspects 23-28 further includes transmitting capability signaling to the RU prior to receiving the uplink communication, wherein the capability signaling indicates bit-width sizes supported by the DU, wherein the bit-width parameter for the PRB is based on the bit-width sizes supported by the DU.

[0135] Aspect 30 is an apparatus for wireless communication at a DU, comprising: means for signaling, to a RU, a maximum IQ data bit-width for an uplink communication in a control plane message; means for receiving a bit-width parameter per PRB for the uplink communication; and means for receiving the uplink communication from the RU based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0136] In Aspect 31, the method of Aspect 30 further includes means for performing the method of any of Aspects 24-29.

[0137] Aspect 32 is an apparatus for wireless communication at a DU, comprising a memory; and at least one processor coupled to the memory, the memory and the at least one processor configured to perform the method of aspects 23-29.

[0138] Aspect 33 is a computer-readable medium storing computer executable code for wireless communication at a DU, the code when executed by a processor causes the processor to perform the method of any of aspects 23-29.

[0139] Aspect 34 is a method of wireless communication at a RU, the method comprising: receiving, from a DU, a first indication of a maximum IQ data bit-width for an uplink communication in a control plane message; transmitting a second indication of a bit-width parameter per PRB for the uplink communication; and transmitting the uplink communication to the DU based on at least one of the maximum IQ data bit-width or the bit-width parameter for the PRB.

[0140] In aspect 35, the method of aspect 35 further includes that the first indication of the maximum IQ data bit-width is received in a user plane compression header (udCompHdr), and wherein the second indication of the bit-width parameter per the PRB is transmitted in a user plane compression parameter (udCompParam).

[0141] In aspect 36, the method of aspect 34 or aspect 35 further includes that the uplink communication is transmitted based on the maximum IQ data bit-width for the DU that does not support per-PRB bit-width granularity.

[0142] In aspect 37, the method of any of aspects 34-36 further includes receiving capability signaling from the DU prior to transmitting the uplink communication, wherein the capability signaling indicates that the DU does not support the PRB bit-width granularity.

[0143] In aspect 38, the method of any of aspects 34-37 further includes that the uplink communication is transmitted based on the bit-width parameter for the PRB for the DU that supports per-PRB bit-width granularity.

[0144] In aspect 39, the method of any of aspects 34-38 further includes receiving capability signaling from the DU prior to transmitting the uplink communication, wherein the capability signaling indicates that the DU supports the PRB bit-width granularity.

[0145] In Aspect 40, the method of any of Aspects 34-39 further includes receiving capability signaling from the DU prior to transmitting the uplink communication, where the capability signaling indicates a bitwidth size supported by the DU, where the bitwidth parameter for the PRB is based on the bitwidth size supported by the DU.

[0146] Aspect 41 is an apparatus for wireless communication at a RU, comprising: means for receiving, from a DU in a control plane message, a first indication of a maximum IQ data bitwidth for an uplink communication; means for transmitting a second indication of a per-PRB bitwidth parameter for the uplink communication to the DU; and means for transmitting the uplink communication to the DU based on at least one of the maximum IQ data bitwidth or the bitwidth parameter for the PRB.

[0147] In Aspect 42, the method of Aspect 41 further includes means for performing the method of any of Aspects 35-40.

[0148] Aspect 43 is an apparatus for wireless communication at a RU, comprising: a memory; and at least one processor coupled to the memory, the memory and the at least one processor configured to perform the method of Aspects 34-40.

[0149] Aspect 44 is a computer-readable medium storing computer executable code for wireless communication at a RU, the code when executed by a processor causes the processor to perform the method of any of Aspects 34-40.

[0150] It should be understood that the particular order or hierarchy of various blocks of the disclosed process / method operations is an illustration. It should be appreciated that the specific order or hierarchy of various blocks of the processes / methods could be rearranged based on design. Furthermore, some blocks could be processed in parallel or concurrently with one another. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

[0151] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Terms such as "if," "as long as," and "when" should be interpreted as meaning "in the event that" rather than indicating a substantive timing result. That is, these phrases (e.g., "when") do not imply a direct temporal relationship, or a response to the happening of an action, but rather simply mean "in the event that," without requiring a particular or immediate temporal or reactive relationship. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of the group consisting of A, B, and C," "one or more of the group consisting of A, B, and C," and "A, B, and / or C" include in combinations A, B, and / or C, and can include multiple A's, B's, or C's. In other words, "at least one of A, B, or C" and "one or more of A, B, or C" include four combinations: A alone, B alone, C alone, and A+B+C. Similarly, "at least one of the group consisting of A, B, and C" and "one or more of the group consisting of A, B, and C" include A alone, B alone, C alone, A+B, A+C, B+C, and A+B+C. It is further noted that all or a portion of two or more of the aspects described herein can be combined to form aspects that are not expressly described but that are nonetheless within the scope of the disclosure. In addition, any reference to claim interpretation is not meant to be a construction of any claim, unless such construction is explicitly provided by the claim itself.

Claims

1. A method for wireless communication at a distributed unit (DU), the method comprising: Signal to the radio unit (RU) to notify the maximum IQ data bit width for downlink communication associated with the segment identifier (ID); The RU is signaled with the bit width parameters for the downlink communication of each physical resource block (PRB); Before transmitting the downlink communication, capability signaling is received from the RU, wherein the capability signaling indicates that the RU does not support the PRB bit width granularity or that the RU supports the PRB bit width granularity; as well as The downlink communication is transmitted to the RU based on at least one of the maximum IQ data bit width or the bit width parameter used for the PRB, wherein the downlink communication is transmitted based on the maximum IQ data bit width for RUs that do not support per-PRB bit width granularity, and wherein the downlink communication is transmitted based on the bit width parameter used for the PRB for RUs that support per-PRB bit width granularity.

2. The method of claim 1, wherein the maximum IQ data bit width is signaled in the user plane compression header (udCompHdr), and wherein the bit width parameter of each PRB is signaled in the user plane compression parameter (udCompParam).

3. The method of claim 1, further comprising: Before transmitting the downlink communication, capability signaling is received from the RU, wherein the capability signaling indicates a bit width size supported by the RU, and the bit width parameter for the PRB is based on the bit width size supported by the RU.

4. A method for wireless communication at a radio unit (RU), the method comprising: Receive a first indication from the Distributed Unit (DU) of the maximum IQ data bit width for downlink communication associated with the segment identifier (ID); Receive a second indication of the bit width parameter for the downlink communication for each physical resource block (PRB) from the DU; Before receiving the downlink communication, a capability signaling is transmitted to the DU, wherein the capability signaling indicates that the RU does not support the PRB bit width granularity or that the RU supports the PRB bit width granularity; as well as The downlink communication is received from the distributed unit (DU) based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB, wherein the downlink communication is received based on the maximum IQ data bit width for the RU that does not support per-PRB bit width granularity, and wherein the downlink communication is received based on the bit width parameter for the PRB for the RU that supports per-PRB bit width granularity.

5. The method of claim 4, wherein the first indication of the maximum IQ data bit width is received in a user plane compression header (udCompHdr), and wherein the second indication of the bit width parameter for each PRB is received in a user plane compression parameter (udComp-Param).

6. The method of claim 4, further comprising: Before transmitting the downlink communication, capability signaling is transmitted to the DU, wherein the capability signaling indicates a bit width size supported by the RU, and the bit width parameter for the PRB is based on the bit width size supported by the RU.

7. A method for wireless communication at a distributed unit (DU), the method comprising: In the control plane message, the maximum IQ data bit width for uplink communication is signaled to the radio unit (RU); Receive bit width parameters for the uplink communication per physical resource block (PRB) from the RU; Before receiving the uplink communication, a capability signaling is transmitted to the RU, wherein the capability signaling indicates that the DU does not support the PRB bit width granularity or that the DU supports the PRB bit width granularity; as well as The uplink communication is received from the RU based on at least one of the maximum IQ data bit width or the bit width parameter for the PRB, wherein the uplink communication is received based on the maximum IQ data bit width for the DU that does not support per-PRB bit width granularity, and wherein the uplink communication is received based on the bit width parameter for the PRB for the DU that supports per-PRB bit width granularity.

8. The method of claim 7, wherein the maximum IQ data bit width is signaled in the user plane compression header (udCompHdr), and wherein the bit width parameter of each PRB is received in the user plane compression parameter (udCompParam).

9. The method of claim 7, further comprising: Before receiving the uplink communication, capability signaling is transmitted to the RU, wherein the capability signaling indicates the bit width size supported by the DU, and the bit width parameter for the PRB is based on the bit width size supported by the DU.

10. A method for wireless communication at a radio unit (RU), the method comprising: In the control plane message, a first indication of the maximum IQ data bit width for uplink communication is received from the distributed unit (DU); Transmit a second indication of the bit width parameters for the uplink communication per physical resource block (PRB) to the DU; Before transmitting the uplink communication, capability signaling is received from the DU, wherein the capability signaling indicates that the DU does not support the PRB bit width granularity or that the DU supports the PRB bit width granularity; as well as The uplink communication is transmitted to the DU based on at least one of the maximum IQ data bit width or the bit width parameter used for the PRB, wherein the uplink communication is transmitted based on the maximum IQ data bit width for DUs that do not support per-PRB bit width granularity, and wherein the uplink communication is transmitted based on the bit width parameter used for the PRB for DUs that support per-PRB bit width granularity.

11. The method of claim 10, wherein the first indication of the maximum IQ data bit width is received in a user plane compression header (udCompHdr), and wherein the second indication of the bit width parameter for each PRB is transmitted in a user plane compression parameter (ud-CompParam).

12. The method of claim 10, further comprising: Before transmitting the uplink communication, capability signaling is received from the DU, wherein the capability signaling indicates a bit width size supported by the DU, and the bit width parameter for the PRB is based on the bit width size supported by the DU.

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