Method for transmitting data between radio unit of radio access network and baseband unit of radio access network, radio unit, baseband unit and computer program

Abstract

A method of communicating data between a radio unit of a radio access network and a baseband unit of the radio access network, a radio unit, a baseband unit and a computer program. A method of communicating data between a radio unit of a radio access network and a baseband unit of the radio access network is provided. The radio unit and the baseband unit are communicatively coupled via an optical communication link. The method includes transmitting an analog optical data signal between the radio unit and the baseband unit via the optical communication link.

Description

Technical Field

[0001] This invention relates to transmitting data between a radio unit and a baseband unit of a telecommunications network. In particular, this invention relates to a method for transmitting data via an optical communication link.

[0002] Vocabulary

[0003] 3GPP - Third Generation Partnership Project

[0004] ABS - Advanced Base Station

[0005] AP - Access Point

[0006] ASIC - Application-Specific Integrated Circuit

[0007] BB-baseband

[0008] BBU - Baseband Unit

[0009] BS base station

[0010] BSS - Basic Services Set

[0011] BTS-Base Transceiver Station

[0012] CDMA - Code Division Multiple Access

[0013] CD-ROM - Compact Disc Read-Only Memory

[0014] CFR-peak factor decreased

[0015] CRS - Cell-Specific Reference Signal

[0016] CSI-RS - Channel State Information Reference Signal

[0017] CU - Central Unit

[0018] DFE - Digital Front End

[0019] DL-downlink

[0020] DPD - Digital Predistortion

[0021] DSP - Digital Signal Processor

[0022] DU - Distributed Unit or Digital Unit

[0023] DVD-ROM (Digital Universal Disc Read-Only Memory)

[0024] eCPRI - Evolved Universal Public Radio Interface

[0025] EDGE - Enhanced Data Rates for GSM Evolution

[0026] EEPROM - Electrically Erasable Programmable Read-Only Memory

[0027] eNB-Evolution Node B

[0028] EPROM - Erasable Programmable Read-Only Memory

[0029] ESS - Extended Services

[0030] E-UMTS - Evolved UMTS

[0031] E-UTRA - Evolved UTRA

[0032] FDD (Frequency Division Duplex)

[0033] FDMA - Frequency Division Multiple Access

[0034] FFT (Fast Fourier Transform)

[0035] FPGA - Field Programmable Gate Array

[0036] FPPGA - Field Programmable Photon Gate Array

[0037] gNB - Next Generation Node B

[0038] GPRS - General Packet Radio Service

[0039] GSM - Global System for Mobile Communications (2G)

[0040] GSMA-GSM Association

[0041] IEEE (Institute of Electrical and Electronics Engineers)

[0042] IF-Intermediate Frequency

[0043] iFFT - Inverse Fast Fourier Transform

[0044] LTE - Long Term Evolution (4G)

[0045] LTE-A - Advanced LTE

[0046] MAC - Media Access Control

[0047] MC-FDMA - Multi-carrier Frequency Division Multiple Access

[0048] MNO - Mobile Network Operator

[0049] MS-Mobile Station

[0050] MT-Mobile Terminal

[0051] NB-Node B (Radio Base Station Receiver)

[0052] NR - New Radio (5G)

[0053] O-CU - Open Central Unit

[0054] O-DU - Open Distributed Unit

[0055] OFDMA - Orthogonal Frequency Division Multiple Access

[0056] ORAN - Open RAN

[0057] O-RAN - Open RAN Alliance

[0058] O-RU - Open Radio Unit

[0059] PA - Power Amplifier

[0060] PDA - Personal Digital Assistant

[0061] PDCP - Packet Data Convergence Protocol

[0062] PHY - Physical Layer

[0063] PS-Processing Server

[0064] RAM - Random Access Memory

[0065] RAN - Radio Access Network

[0066] RF (Radio Frequency)

[0067] RLC - Radio Link Control

[0068] ROM - Read-Only Memory

[0069] RRC - Radio Resource Control

[0070] RU-Radio Unit

[0071] SC-FDMA - Single-Carrier Frequency Division Multiple Access

[0072] SDAP - Service Data Adaptation Protocol

[0073] SRAN - Single RAN (Non-open RAN)

[0074] SS-Subscriber Station

[0075] TDD - Time Division Duplex

[0076] TDMA (Time Division Multiple Access)

[0077] TE-Terminal Equipment

[0078] TRP - Transmit and Receive Point

[0079] UE (User Equipment)

[0080] UL-Uplink

[0081] UMTS - Universal Mobile Telecommunications System (3G)

[0082] UTRA - Universal Terrestrial Radio Access

[0083] WDM (Wavelength Division Multiplexing) Background Technology

[0084] The functionality provided by a radio access network (RAN) is provided by several functional elements within the RAN. Typically, the functionality to transmit and receive radio signals is provided by one or more radio units (RUs). In some examples, the baseband unit (BBU) provides the functionality to demodulate radio signals and convert them into digital data streams for transmission to the core network. In other examples, the BBU is further subdivided into separate functional elements, described as distributed units (DUs) and centralized units (CUs). De-aggregating BBU functionality into separate functional elements can improve flexibility by allowing the MNO to position functionality among these elements, which can be used to improve performance and scalability. The de-aggregation of BBU functionality is described in 3GPP TR38.801, which is incorporated herein by reference.

[0085] To facilitate functional decoupling, hardware and software components must be interoperable. Open RAN is a technology architecture concept involving the decoupling of the hardware and software components of a radio access network (RAN). It includes open, interoperable interfaces and virtualized RAN. In existing (non-open) SRAN technologies, hardware and software components are typically proprietary. SRAN equipment is often sourced from a single vendor to ensure seamless functionality, security, and efficiency. In contrast, Open RAN introduces open standards for both hardware and software, enabling interoperability between various network elements. Open RAN is of strategic importance to mobile network operators (MNOs) because it promotes vendor diversity, allows for the integration of new suppliers, and enhances supply chain resilience. It also delivers energy efficiency gains by enabling targeted improvements in specific areas of the RAN. Furthermore, Open RAN fosters innovation and competition by providing a more dynamic and efficient network environment. Additionally, it offers opportunities for collaboration with specialized suppliers and facilitates resource optimization by allowing software upgrades without replacing hardware. Open RAN is important in MNO’s long-term network innovation strategy, providing energy efficiency, supply chain diversification, enhanced resilience, and fostering innovation and competition.

[0086] Depending on the network design, some network functions can be provided by different functional elements. In particular, the functional distribution between CU and DU can vary depending on the implementation. The distribution can be selected based on many criteria, such as environment (e.g., urban or rural), cost, performance, load management, and use cases (e.g., gaming, voice, and video applications may have different latency tolerances).

[0087] In some examples, the DU can be located within the edge network of the MNO network. The CU can be located within the core network of the MNO network.

[0088] The functional splitting method among RU, DU, and CU can vary depending on the specific use case and implementation. In one example, referred to as "Split 7.2x," the RU is responsible for the lower portion of Layer 1 (L1, PHY), the DU for the higher portion of Layer 1 (L1, PHY) and the lower portion of Layer 2 (L2), which includes the data link layer and scheduling functions, and the CU for the higher portion of Layer 2 and Layer 3 (L3, network layer) functions. In some examples, the RU is configured to perform beamforming, iFFT, CFR, DPD, DFE, frequency shifting, and power amplification (PA). In some examples, the DU is configured to perform scrambling, modulation, layer mapping, precoding, resource element mapping, I / Q compression elements, MAC elements, and RLC elements. In some examples, the CU is configured to perform PDCP elements and RRC / SDAP elements.

[0089] Other options exist for splitting functionality among functional elements. In another example, known as "Split 8.0," the DU also handles the lower portion of layer 1. Other alternatives exist, such as "Option 6," where the RU handles the higher portion of layer 1.

[0090] In some examples, each DU is connected to one or more RUs via a fronthaul interface. The fronthaul interface may include optical or electrical connections between the DU and one or more RUs. Where the fronthaul interface includes optical connections, it may also incorporate photonics technologies to improve data transmission rates and reduce latency.

[0091] In some examples, the fronthaul interface is the Evolved Common Public Radio Interface (eCPRI), where a binary representation of the baseband signal is created and transmitted digitally via an optical interface. The signal is received optically at the RU and converted into a digital-to-electrical representation. Summary of the Invention

[0092] The method proposed in this disclosure aims to improve the energy efficiency of data transmission via a fronthaul interface. The proposed method also aims to reduce the number of components and losses due to the conversion between the electrical and optical domains. Furthermore, the proposed method aims to provide increased flexibility by increasing the number of feasible options for configuring the network.

[0093] A method is provided for transmitting data between a radio unit and a baseband unit of a radio access network. The radio unit and the baseband unit are communicatively coupled via an optical communication link. The method includes transmitting analog optical data signals between the radio unit and the baseband unit via the optical communication link.

[0094] In the context of this disclosure referring to "analog" signals, this means signals whose values ​​change continuously over time. This contrasts with digital signals, where signals are quantized into discrete values ​​and change periodically over time. For example, a binary digital signal can take only two possible values ​​to represent one and zero. Signal values ​​can be described as "high" and "low" (or "on" and "off").

[0095] In addition to reducing data rates and improving latency, using photonics in the fronthaul interface can also reduce energy consumption and enhance signal processing performance in the RAN. Photonics can also provide the ability to process both high-frequency and low-frequency signals.

[0096] The radio access network can be an open radio access network (open RAN). The radio unit can be an open radio unit (O-RU). The baseband unit can be an open distributed unit (O-DU).

[0097] The baseband unit may include an Open Distributed Unit (O-DU) and an Open Central Unit (O-CU).

[0098] An optical communication link may include one or more optical fibers.

[0099] The radio unit and the baseband unit can be communicatively coupled via a fronthaul interface. The fronthaul interface may include an optical communication link.

[0100] The method may also include multiplexing analog optical data signals with digital optical data signals. The method may also include transmitting digital optical data signals between the radio unit and the baseband unit via an optical communication link.

[0101] Analog optical data signals may involve data plane data, while digital optical data signals may involve control plane data.

[0102] The method may also include using a photonic processor to perform one or more (PHY layer) operations on the optical analog data signal.

[0103] One or more operations may include one or more of the following:

[0104] Beamforming;

[0105] Fast Fourier Transform (FTT);

[0106] Inverse Fast Fourier Transform (iFTT);

[0107] Crest factor reduction (CFR);

[0108] Digital predistortion; and

[0109] Frequency shift.

[0110] These processing operations can be performed more efficiently in the optical domain than in the electrical domain. Therefore, the RAN can operate more efficiently by performing these operations on the optical signal before the signal is converted back to an electrical signal.

[0111] Analog optical data signals can be transmitted at intermediate frequencies.

[0112] Transmitting signals at intermediate frequencies eliminates the need for signal frequency shifting because an intermediate frequency that is already at radio frequency can be selected.

[0113] In the context of the fronthaul interface, "upstream" can refer to data transmitted from RU to BBU, and "downstream" can refer to data transmitted from BBU to RU.

[0114] The electrical signals transmitted between the BBU and RU typically require frequency shifting or modulation using the carrier frequency because electrical signals are more susceptible to noise. Therefore, transmitting the signal as an analog optical signal instead of a digital analog signal eliminates the need for modulation and thus improves the RAN's energy efficiency.

[0115] Furthermore, transmitting signals at baseband frequency simplifies analog-to-digital (A2D) conversion.

[0116] The method may also include conversion between analog electrical data signals and analog optical data signals (at RU).

[0117] The method may also include conversion between analog optical data signals and analog electrical data signals (at the baseband unit).

[0118] The signal can be converted between analog optical data signals and digital electrical data signals in both upstream and downstream directions.

[0119] Converting between analog optical data signals and digital electrical data signals can include:

[0120] Converting between analog optical data signals and second analog electrical data signals; and

[0121] It converts between the second analog electrical data signal and the digital electrical data signal.

[0122] Resource mapping can be performed on analog electrical signals.

[0123] A radio access network may include multiple radio units that are communicatively coupled to a baseband unit via an optical communication link.

[0124] The method may also include transmitting analog optical data signals between the second radio unit and the baseband unit via an optical communication link.

[0125] An optical communication link may include a separate optical fiber for each of the multiple radio units. The optical communication link may also include a path switch or optical splitter to transmit optical analog signals between the baseband unit and each radio unit.

[0126] A radio unit is also provided that is configured to perform any of the methods described above.

[0127] A baseband unit (or DU) is also provided that can be configured to perform any of the methods described above.

[0128] A computer program comprising instructions is also provided, which, when executed on a processor, cause the processor to perform any of the methods described above. The processor may include one or more processing elements. Processing elements may include one or more digital electrical processors, one or more digital photonic processors, and / or one or more analog photonic processors.

[0129] A photonic processor is also provided that can be configured to perform any of the methods described above. Attached Figure Description

[0130] Figure 1 The illustration shows an example of eCPRI double conversion for optical data round trip in the fronthaul interface, as represented by the split 7.2x.

[0131] Figure 2 The illustration shows an example of eCPRI double conversion for optical data round trip in the fronthaul interface for the split 8.0x representation.

[0132] Figure 3 The diagram illustrates the elements of the transmission chain, in which processing can be performed on the split 7.2x optical analog signal.

[0133] Figure 4 The diagram illustrates the elements of the transmission chain, in which processing can be performed on the split 8.0 optical analog signal.

[0134] Figure 5 The diagram illustrates the overall connectivity of the fronthaul interfaces between two DUs and two RUs, based on a specific example. Detailed Implementation

[0135] The purpose of this disclosure is to provide an improved fronthaul interface between a BBU (e.g., a DU of the BBU) and an RU. Depending on the type of function split used in the RAN, the fronthaul interface between the BBU and RU can be implemented in different ways. In some examples, the fronthaul interface can be between function blocks representing the lower and higher portions of Layer 1 in the transport chain (in the case of split 7.2x). Figure 1 The illustration shows an example of a double conversion of optical data to and from the fronthaul interface for a split 7.2x representation.

[0136] In other examples, the fronthaul interface can be implemented between the lower part of Layer 1 and the RF function (in the case of split 8.0). Figure 2 The illustration shows an example of a double conversion of optical data to and from the fronthaul interface for the split 8.0 representation.

[0137] Various signal processing operations are performed in the RU. For example, the RU can perform crest factor reduction and digital predistortion operations. In some examples, the RU also includes a digital front-end (DFE), which converts the signal into an analog electrical signal at radio frequency or intermediate frequency, which requires frequency shifting to a higher frequency before transmission. Finally, the signal is pre-amplified and then amplified.

[0138] The transport chain can also include FFT and inverse FFT processing operations, as well as beamforming operations. Depending on the function split used, these can be performed by the RU (in the case of split 7.2x) or the DU (in the case of split 8.0).

[0139] To provide energy savings, this disclosure proposes a new standard for the fronthaul interface between the RU and BBU, wherein data is transmitted in an optical-analog format. This data format also allows for the possibility of using photonic computing for one or more processing steps in the transport chain.

[0140] In some examples, the RU is one of the most power-consuming devices in the network. Some processing operations can be performed more energy-efficiently in the optical domain. For example, a photonic processor can perform processing operations such as beamforming, digital predistortion, and frequency shifting on analog optical data signals more efficiently than a digital processor can perform equivalent processing operations on electrical digital signals. Therefore, by converting the signal processing of one or more processing operations to the optical domain, the overall power consumption of the network can be reduced.

[0141] Performing signal processing on optical signals can also improve performance compared to processing digital signals. For example, performing frequency shifting on optical signals may produce less noise than performing an equivalent operation on electrical signals.

[0142] For example, beamforming may require complex multiplications to control how the signal is delayed in different directions to achieve the overall directionality of the signal. In the optical domain, beamforming can be performed in a much simpler way by utilizing specific physical effects of light and customizing different optical path lengths.

[0143] In some examples, the order of processing operations can be adjusted to selectively move operations to the optical domain. For instance, beamforming (which can be performed before the iFFT in the electrical domain) can be performed after the iFFT in the optical domain. This is because the customization of the optical path length is best performed in the time domain.

[0144] When the signal is in the frequency domain, digital predistortion can be performed more efficiently in the optical domain. Therefore, DPD can be performed after iFFT in the electrical domain and before iFFT in the optical domain.

[0145] While many of the processing operations described above can be performed more efficiently in the optical domain, it is not necessary to convert all processing operations to the optical domain. In some examples (e.g., in the case of Split 8.0), DPD can be performed in the electrical domain, while iFFT is performed in the optical domain. In other examples, both DPD and iFFT can be performed in the electrical domain.

[0146] Converting only specific elements of the transmission chain to the analog optical domain may require multiple conversion steps between digital electrical signals and optical analog signals (and / or optical digital signals). These conversions can be inefficient and may increase power consumption. Therefore, to improve performance, this disclosure proposes transmitting data signals in optical analog format via a fronthaul interface and performing signal processing operations on the optical analog signals without converting the signals back to electrical digital format. This allows processing operations to be performed in the optical domain without increasing the number of signal format conversions.

[0147] In some prior art examples, the fronthaul interface between the BBU and RU includes an optical communication link. However, in these prior art examples, data is transmitted in an optical digital format. In contrast, this disclosure proposes transmitting data between the BBU and RU in an optical analog format. In some examples, this can be achieved by using different couplers to transmit data via optical fiber.

[0148] In some prior art examples, the signal is converted to analog format by the digital front-end (DFE) element of the RU before being transmitted in analog format by the RF antenna. In contrast, according to this disclosure, the baseband signal can be converted from digital binary to analog optical at the DU, and the signal can be transmitted to the RU in analog format via the fronthaul interface. Therefore, the RU can perform all processing in analog format and may not need to convert the signal to digital format.

[0149] In some examples, the baseband signal can be immediately converted from digital binary to optical analog format at the DU before transmission via the fronthaul interface. Alternatively, the signal can be converted to optical analog format earlier in the transmission chain, and processing operations in the DU can be performed in the optical domain. For example, beamforming and iFFT (which are performed by the split 8.0 DU) can be performed in the optical domain. Furthermore, resource mapping (performed by the split 7.2x and split 8.0 DUs) can be performed in the optical domain.

[0150] Signals can be directly converted from digital electrical format to optical analog format. Alternatively, signals can be converted from digital electrical format to digital analog format, and then from digital analog format to optical analog format. Some processing operations can be performed on signals in digital analog format. For example, resource mapping can be performed in an analog manner.

[0151] In some existing techniques, the optical digital signal received by the RU via the fronthaul interface is converted into an electrical digital signal by the RU, and then converted back into an optical signal, this time an analog signal. Therefore, compared with existing techniques, by converting the fronthaul interface to optical analog and performing processing in the optical domain, two electro-optical conversion steps in the RU can be eliminated.

[0152] In a transport chain, a processing block adjacent to the fronthaul interface can be a suitable candidate for performing processing in the optical domain rather than the electrical domain, without requiring additional conversion steps. Similarly, if a processing block is converted to the optical domain, the adjacent processing block immediately upstream or downstream can also be converted to the optical domain without requiring additional conversion steps.

[0153] Figure 3 The diagram illustrates the elements of the transmission chain, in which processing can be performed on the split 7.2x optical analog signal.

[0154] Figure 4 The diagram illustrates the elements of the transmission chain, in which processing can be performed on the split 8.0 optical analog signal.

[0155] In some examples, WDM modulation can be used to color-modulate the control plane as a 100MHz Ethernet digital stream into a single fiber.

[0156] WDM path switches can be used to create dynamic associations between RUs and DUs. For example, two RUs can be physically connected to the same DU, and traffic can be split between the two RUs during the day and sent to a single RU at night.

[0157] Figure 5 The diagram illustrates the overall connectivity of the fronthaul interfaces between two DUs and two RUs, based on a specific example.

[0158] Depending on the functional split used, different blocks need to be converted. Split 7.2x is specified by the Open RAN Consortium (referred to as "O-RAN" in the standard), but Open RAN can often be implemented with other functional splits (such as split 8.0). The process may involve changes in methodology, such as beamforming being preferably implemented in the time domain (and therefore preferably performed before and / or after the iFFT), and the FFT being difficult to implement in the optical domain (so it can be implemented in the electrical domain).

[0159] Although specific embodiments have been described above, those skilled in the art will understand that various modifications and variations are possible. For example, while this disclosure relates to existing network architectures, it will be understood that changes to the architecture (and / or terminology) are possible, but this disclosure may still apply in such cases. Furthermore, combinations of any particular features shown with reference to one or more embodiments are also provided, even if such combinations are not explicitly detailed herein.

[0160] For example, in the case of an application involving servers, this could actually be a pair of servers (a primary server and a failover server) for redundancy.

[0161] In the context of this application involving "network entities," those skilled in the art will understand that network entities can actually be provided by multiple geographically distributed servers.

[0162] The open radio access network described above can be used in cellular networks to provide services to one or more user equipment (UEs). Examples of UEs include various fixed and mobile devices that transmit user data and / or various types of control information to and from base stations. UEs can be referred to as terminal equipment (TE), mobile station (MS), mobile terminal (MT), user terminal (UT), subscriber station (SS), radio equipment, personal digital assistant (PDA), wireless modem, handheld device, etc.

[0163] While the examples above are described with respect to specific radio access networks (e.g., 5G radio access networks), these methods, technologies, apparatuses, and systems can be applied to a wide variety of radio multiple access systems. Examples of multiple access systems include CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and MC-FDMA. CDMA can be implemented using radio technologies such as UTRA or CDMA2000. TDMA can be implemented using radio technologies such as GSM, GPRS, or EDGE. OFDMA can be implemented using radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or E-UTRA. UTRA is part of UMTS. 3GPP LTE is part of E-UMTS using E-UTRA. 3GPP LTE uses OFDMA in the downlink and SC-FDMA in the UL. LTE-A is an evolution of 3GPP LTE. 3GPP NR uses OFDMA for both downlink and uplink and can operate in both FDD and TDD modes. For ease of description, it is assumed that the present invention is applied to 3GPP NR. However, the technical features of the present invention are not limited thereto. For example, although the following detailed description is based on a mobile communication system corresponding to a 3GPP NR system, aspects of the present invention that are not specific to 3GPP NR are also applicable to other mobile communication systems. Furthermore, the technical features of the present invention can be applied to future iterations of multiple access systems defined in the 3GPP standard, such as (but not limited to) 6G.

[0164] These examples can be executed on any suitable data processing device, such as a personal computer, laptop computer, mobile phone, server, virtual machine, etc. For purposes of discussion, the above description of the systems and methods has been simplified and is intended to provide specific examples to illustrate the invention. As those skilled in the art will appreciate, different types of systems and methods can be used. It will be understood that the boundaries between logical blocks are merely illustrative, and alternative embodiments may combine logical blocks or elements, or functional alternative decompositions may be imposed on various logical blocks or elements.

[0165] It will be understood that the functionality mentioned above can be implemented as one or more corresponding modules, as hardware and / or software. For example, the functionality mentioned above can be implemented as one or more software components executed by the system's processor. Alternatively, the functionality mentioned above can be implemented as hardware, such as on one or more FPGAs and / or one or more ASICs and / or one or more FPGAs and / or one or more DSPs and / or other hardware arrangements. The method steps included herein or implemented in the flowcharts described above can each be implemented by their respective corresponding modules. Furthermore, multiple method steps included herein or implemented in the flowcharts described above can be implemented together by a single module.

[0166] Any of the methods described herein can be implemented as computer software or a "computer program". A computer program can be configured to control a network entity (e.g., a server or group of servers) to perform any of the methods disclosed herein. A network entity (e.g., a server or group of servers) within a cellular network may also be provided, configured to operate according to some of the methods disclosed herein. For example, a network entity may include a processor and at least one communication interface, particularly including one or both a transmitter and a receiver.

[0167] It also provides storage and transmission media for carrying computer programs. A computer program may include one or more instructions or code that, when executed by a computer, cause the described methods to be performed. A computer program may be a sequence of instructions designed to execute on a computer system and may include subroutines, functions, procedures, modules, object methods, object implementations, executable applications, applets, servlets, source code, object code, shared libraries, dynamic link libraries, and / or other sequences of instructions designed to execute on a computer system. Storage media may be disks (such as hard disks or floppy disks), optical disks (such as CD-ROMs, DVD-ROMs, or Blu-ray discs), or memory (such as ROM, RAM, EPROM, EEPROM, flash memory, or portable / removable memory devices). Transmission media may be communication signals, data broadcasts, communication links between two or more computers, etc.

[0168] Unless otherwise stated, each feature disclosed in this specification can be replaced by alternative features serving the same, equivalent, or similar purpose. Therefore, unless otherwise stated, each disclosed feature is merely an example of a general series of equivalent or similar features.

[0169] As used herein, including in the claims, unless the context otherwise indicates, the singular form of a term herein shall be construed as including the plural form, and vice versa. For example, unless the context otherwise indicates, singular references included herein in the claims, such as “a” or “an” (such as a UE, network entity, server, or cell), mean “one or more” (e.g., one or more UEs, one or more network entities, one or more servers, or one or more cells). Throughout the description and claims of this disclosure, the words “comprising,” “containing,” “having,” and “including,” as well as variations of the words (e.g., “comprising” and “comprises” or the like), mean “containing” and are not intended to exclude other components.

[0170] Unless otherwise claimed, the use of any and all example or exemplary language (“e.g., for instance,” “such as,” “for example,” and similar language) provided herein is intended only to better illustrate the invention and does not indicate any limitation on the scope of the invention. No language in the specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0171] Unless otherwise stated or required by context, any steps described in this specification may be performed in any order or simultaneously. Furthermore, the fact that a step is described as being performed after another step does not preclude the performance of any intervention step.

[0172] All aspects and / or features disclosed in this specification can be combined in any combination, except where at least some of such features and / or steps are mutually exclusive. Specific combinations of aspects as described herein may offer additional benefits, such as determining a set of compensation parameters and applying that set to aspects of the measurement. In particular, preferred features of the invention apply to all aspects of the invention and can be used in any combination. Similarly, features described in non-essential combinations may be used individually (rather than in combination).

[0173] A method for manufacturing and / or operating any of the devices disclosed herein is also provided. This method may include steps of providing each of the disclosed features and / or configuring or using the respective features to achieve their illustrative functions.

Claims

1. A method for transmitting data between a radio unit of a radio access network and a baseband unit of the radio access network, wherein the radio unit and the baseband unit are communicatively coupled via an optical communication link, the method comprising: Analog optical data signals are transmitted between the radio unit and the baseband unit via the optical communication link.

2. The method according to claim 1, wherein the radio access network is an open radio access network (open RAN), wherein the radio unit is an open radio unit (O-RU), and wherein the baseband unit is an open distributed unit (O-DU).

3. The method according to any of the preceding claims, wherein the optical communication link comprises one or more optical fibers.

4. The method according to any of the preceding claims, wherein the radio unit and the baseband unit are communicatively coupled via a fronthaul interface, and wherein the fronthaul interface includes the optical communication link.

5. The method according to any of the preceding claims, further comprising: The analog optical data signal is multiplexed with the digital optical data signal; as well as The digital optical data signal is transmitted between the radio unit and the baseband unit via the optical communication link.

6. The method of claim 5, wherein the analog optical data signal relates to data plane data and the digital optical data signal relates to control plane data.

7. The method according to any of the preceding claims, further comprising: The photonic processor performs one or more operations on the optical analog data signal.

8. The method of claim 7, wherein the one or more operations comprise one or more of the following: Beamforming; Fast Fourier Transform (FTT); Inverse Fast Fourier Transform (iFTT); Digital predistortion; and Frequency shift.

9. The method according to any of the preceding claims, wherein the analog optical data signal is transmitted at an intermediate frequency.

10. The method according to any of the preceding claims, further comprising: Converting between analog electrical data signals and analog optical data signals; and / or The conversion is performed between the analog optical data signal and the digital electrical data signal.

11. The method of claim 10, wherein the conversion between the analog optical data signal and the digital electrical data signal comprises: The conversion is performed between the analog optical data signal and the second analog electrical data signal; as well as The conversion is performed between the second analog electrical data signal and the digital electrical data signal.

12. The method according to any of the preceding claims, wherein the radio access network comprises a plurality of radio units communicatively coupled to the baseband unit via the optical communication link.

13. A radio unit configured to perform the method according to any of the preceding claims.

14. A baseband unit configured to perform the method according to any one of claims 1 to 12.

15. A computer program comprising instructions that, when executed on a processor, cause the processor to perform the method according to any one of claims 1 to 12.

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