A radio frequency unit for wireless communication with a baseband unit according to a radio access network protocol and a baseband unit

Abstract

The present disclosure relates to a radio unit (RU) for wireless communication with a base band unit (BBU) according to a radio access network (RAN) protocol. The RU is configured to establish a first bidirectional connection with the BBU, the first bidirectional connection being allocated on a first frequency band of an electromagnetic spectrum. The RU is configured to establish a second bidirectional connection with the BBU, the second bidirectional connection being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication. The RU is configured to communicate with the BBU using the second bidirectional connection in case one or more channel quality parameters of the first bidirectional connection do not satisfy a threshold value of the respective channel quality parameter, or in case the first bidirectional connection is interrupted.

Description

Technical Field

[0001] This disclosure relates to a radio unit (RU) for wireless communication with a base band unit (BBU) according to a radio access network (RAN) protocol, and a BBU for wireless communication with an RU according to the RAN protocol. Furthermore, this disclosure relates to a method for wireless communication between a BBU and an RU according to the RAN protocol. Additionally, this disclosure relates to an RU for wireless communication with BBUs in a BBU pool according to the RAN protocol, and a BBU pool for wireless communication with one or more RUs according to the RAN protocol. Background Technology

[0002] Wireless communication devices such as baseband units (BBUs) and radio units (RUs) can communicate wirelessly with each other. This wireless communication can be performed according to radio access network (RAN) protocols. This allows wireless communication to be provided in the area covered by the communication devices (e.g., one or more cells served by the RUs) according to the RAN protocol. Summary of the Invention

[0003] In 5G and beyond radio access networks, centralized RAN or cloud RAN (C-RAN) and its virtualized variant (vRAN) are becoming increasingly prevalent and are being viewed by operators as a solution to densify networks in a way that reduces CAPEX and OPEX. C-RAN is a network paradigm that aggregates the main baseband functions of multiple radio access points into a centralized baseband unit (BBU) pool, while retaining radio frequency modules and potential first digital processing capabilities (e.g., analog-to-digital and digital-to-analog conversion, inverse fast Fourier transform (IFFT) / fast Fourier transform (FFT), beamforming, digital predistortion) in radio units (RUs) remotely deployed at cell sites. C-RAN can also be referred to as vRAN when the network functions in the BBU are virtualized on a general-purpose x86 server. The multiple communication links connecting the BBU pool to the corresponding RUs are typically referred to as the fronthaul infrastructure. In the following text, the term "C-RAN" is generally used to refer to any of centralized RAN, cloud RAN, or virtualized RAN.

[0004] C-RAN not only reduces deployment and maintenance costs but also enhances performance through features such as inter-unit (i.e., between multiple RUs) coordination and by enabling network virtualization, slicing, and openness. Furthermore, in scenarios where the radio infrastructure is managed by a third party (e.g., a tower provider or a neutral host), C-RAN operators can dynamically share radio and baseband resources. On the other hand, C-RAN presents significant challenges to the design of network architecture and appropriate fronthaul transmission links within the network.

[0005] Fiber-optic connections have long been the mainstream technology for fronthaul. However, fiber-optic fronthaul may not be able to scale efficiently to meet the higher levels of density and flexibility expected in future network deployments. Therefore, wireless fronthaul is beginning to be seen as a viable, economical, and attractive alternative, especially in markets such as Europe where the cost of deploying new fiber optic infrastructure is very high.

[0006] Compared to fiber-optic-based fronthaul, wireless fronthaul offers advantages in flexibility and scalability. However, achieving the required performance in wireless fronthaul while maintaining 24 / 7 availability presents challenges, particularly in terms of capacity and latency. Millimeter waves (i.e., in the range of 30 GHz to 300 GHz), free-space optics (FSO), and Asia-Pacific Hertz frequencies are promising candidates for meeting the transmission rate requirements of wireless fronthaul, but their disadvantage is that transmission at these frequencies is particularly susceptible to propagation loss and atmospheric absorption, making wireless fronthaul links highly vulnerable to failure and interference.

[0007] Figure 1 A pool of baseband units (BBUs) is shown, providing wireless fronthaul connectivity for multiple radio units (RUs). Figure 1 An example of a wireless fronthaul connection between a BBU pool comprising multiple base band units (BBUs) and three distinct radio units (RUs) RU1, RU2, and RU3 is shown, where each RU is associated with a corresponding cell (i.e., cell 1, cell 2, and cell 3, respectively). The fronthaul connections between the BBU pool and the RUs (RU1, RU2, and RU3) are referred to as Link 1, Link 2, and Link 3, respectively. Figure 1For example, due to favorable weather (e.g., sunny day), the quality of fronthaul link 2 is good; that is, the radio signal transmitted between the BBU pool and the RU (RU 2) via fronthaul link 2 is not interfered with by adverse weather conditions (e.g., rain). The quality of fronthaul link 3 deteriorates due to adverse weather conditions (e.g., light rain). Nevertheless, fronthaul link 3 still supports wireless communication between the BBU pool and the RU (RU 3), therefore, there is no service interruption in cell 3 served by RU (RU 3). Figure 1 In the example, suppose fronthaul link 1 is interrupted (i.e., fails) due to severe weather conditions (such as a strong storm). Such a failure on wireless fronthaul link 1 would cause service interruption in cell 1, which is served by RU (RU 1). In other words, cell 1 might become an isolated cell without any service, such as... Figure 1 As shown.

[0008] In view of the above, this disclosure aims to provide a wireless communication device, such as an RU or BBU, for handling potential failures in bidirectional connectivity with another wireless communication device. The object of this disclosure may be to provide a wireless communication device, such as an RU or BBU, for minimizing the downtime of bidirectional connectivity with another communication device by ensuring 24 / 7 availability of the bidirectional connectivity.

[0009] These and other objectives are achieved by means of the solutions described in the independent claims of this disclosure. Advantageous implementations are further defined in the dependent claims.

[0010] The first aspect of this disclosure provides a radio unit (RU) for wireless communication with a baseband unit (BBU) according to a radio access network (RAN) protocol. The RU is used to establish a first bidirectional connection with the BBU, the first bidirectional connection being allocated on a first frequency band of the electromagnetic spectrum. The RU is also used to establish a second bidirectional connection with the BBU, the second bidirectional connection being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for radio access communication. That is, the second frequency band is used for radio access communication. The RU is used to communicate with the BBU using the second bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection is interrupted.

[0011] Since the RU according to the first aspect is used to switch from the first bidirectional connection to the second bidirectional connection in the event that one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter or the first bidirectional connection is interrupted (i.e., fails), the RU according to the first aspect is used to handle possible failures of the first bidirectional connection. Since the RU is used to wirelessly communicate with the BBU via the second bidirectional connection in the event that one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter or the first bidirectional connection is interrupted, the RU is used, for example, to minimize the failure period of the bidirectional connection with the BBU by ensuring the 24 / 7 availability of the bidirectional connection with the BBU (either the first bidirectional connection or the second bidirectional connection).

[0012] The RAN protocol can be a 5G New Radio (NR) RAN protocol. RUs can be used to serve the cell. The first bidirectional connection can be called a "fronthaul connection." The second bidirectional connection can be called a "midhaul connection" or "backhaul connection." For example, radio access communication can include one or more International Mobile Telecommunications (IMT) services. The first and second bidirectional connections are radio connections. The first and second bidirectional connections can be simply referred to as "first connection" and "second connection," respectively.

[0013] A BBU can be implemented on one or more computing resources, such as one or more servers, one or more central processing units (CPUs), etc. A BBU can be part of a collection of multiple BBUs (such as a BBU pool) for communicating with different RUs.

[0014] An RU can be used for wireless communication with multiple BBUs (e.g., a BBU pool). An RU can also be used for wireless communication with BBUs within a pool of BBUs. An RU can be referred to as an "enhanced RU (eRU)". The terms "channel" and "link" can be used as synonyms for the term "connection".

[0015] The phrase “second frequency band for wireless access communication” can be used as a synonym for the phrase “second frequency band for wireless access communication”.

[0016] The RU can use a second bidirectional connection as an immediate response to an interruption (e.g., a sudden interruption) of the first bidirectional connection. The terms "interruption," "fault," and "outage" can be used synonymously. The first frequency band differs from the second frequency band. For example, the first frequency band can be the E band (e.g., frequencies between 70 GHz and 86 GHz) or the D band (e.g., frequencies between 130 GHz and 175 GHz). For example, the second frequency band can be within 5G NR frequency range 1 (FR1), such as frequencies between 3.4 GHz and 3.8 GHz; or within 5G NR frequency range 2 (FR2), such as frequencies between 24 GHz and 71 GHz. The term "frequency range" can be used synonymously with the term "frequency band." The first frequency band can have a first frequency bandwidth. The second frequency band can have either a first frequency bandwidth or a second frequency bandwidth.

[0017] The first bidirectional connection can employ one of free-space optics (FSO) communication technology, E-band microwave wireless communication technology, and D-band microwave wireless communication technology. That is, the first frequency band can be a band used in FSO communication (e.g., above 300 GHz). Alternatively, the first frequency band can be the D band (e.g., 130 GHz to 175 GHz) or a frequency range that is part of the D band. Alternatively, the first frequency band can be the E band (e.g., 70 GHz to 86 GHz) or a frequency range that is part of the E band.

[0018] When the first bidirectional connection uses FSO communication technology, fog is one of the main / dominant atmospheric phenomena that may cause the first bidirectional connection to fail (i.e., be interrupted). When the first bidirectional connection uses E-band or D-band microwave wireless communication technology, rain is one of the main / dominant atmospheric phenomena that may cause the first bidirectional connection to fail (i.e., be interrupted). Since a failure of the first bidirectional connection triggers the activation of the second bidirectional connection, the RU supports minimizing the downtime of the bidirectional connection with the BBU, for example, by ensuring the 24 / 7 availability of the bidirectional connection with the BBU.

[0019] Each threshold of the corresponding channel quality parameter can be a predefined threshold. A corresponding channel quality parameter that does not meet a threshold can be less than or greater than the threshold, depending on the type of the corresponding channel quality parameter. One or more channel quality parameters can be, or can include, for example, a maximum bit rate achievable for a target bit error rate (BER). For the maximum bit rate achievable for a target BER, the threshold can be the minimum value of the channel quality parameter. For example, if the maximum bit rate achievable for a target BER is less than the threshold, the maximum bit rate achievable for a target BER for the first bidirectional channel does not meet the threshold. One or more channel quality parameters can be one or more numerical values ​​that establish a comparison between the channel performance and a reference value (i.e., a threshold). One or more numerical values ​​can be obtained by measurements performed on the radio frequency signal or the digitally converted radio frequency signal transmitted on the channel. For example, in addition to or alternatively to the maximum bit rate achievable for the target BER, one or more channel quality parameters may be or may include at least one of the following: Received Signal Strength (RSS), Mean Square Error (MSE) of the received symbol constellation relative to the reference symbol constellation used on the link, Signal-to-Noise Ratio (SNR), and Signal-to-Interference-plus-Noise Ratio (SINR). RSS can be calculated on the radio frequency signal using dedicated electronic circuitry prior to analog-to-digital conversion. MSE, SNR, or SINR can be calculated by a digital processor after analog-to-digital conversion.

[0020] RU can be used for wireless communication, such that the first bidirectional connection and the second bidirectional connection are mutually exclusive (i.e., when the first bidirectional connection is active, the second bidirectional connection is inactive, and vice versa, when the second bidirectional connection is active, the first bidirectional connection is inactive).

[0021] RUs can be used in C-RAN systems. In such C-RAN systems, a BBU pool, comprising multiple BBUs, can be connected to one or more remote RUs via corresponding one or more fronthaul links. When an RU is used in a C-RAN system, a fronthaul link represents the first bidirectional connection that the RU can establish with a BBU in the BBU pool.

[0022] In one implementation of the first aspect, the RU is used to establish a first bidirectional connection with the BBU and to provide access to users by implementing the Layer 1 function of the RAN protocol.

[0023] In one implementation of the first aspect, the RU is used to establish a second bidirectional connection with the BBU by implementing the layer 1 and layer 2 functions of the RAN protocol.

[0024] In one implementation of the first aspect, the RU is used to activate the layer 2 function of the RAN protocol to establish a second bidirectional connection with the BBU in the event of a first bidirectional connection interruption.

[0025] Therefore, the RU can automatically activate the Layer 2 function of the RAN protocol without signaling exchange with the BBU. Optionally, the RU is used to communicate with the BBU according to the 5G New Radio (NR) protocol. The RU can be used to establish a second bidirectional connection with the BBU by establishing an F1 interface-based connection between the RU and the BBU, wherein the RU includes a distributed unit (DU) for managing the F1 interface-based connection. That is, the RAN protocol can be the 5G New Radio (NR) RAN protocol. The DU can be a 5G integrated access and backhaul DU (5G IAB DU). The RU can be used to establish its DU without signaling exchange with the BBU in the event of a first bidirectional connection interruption.

[0026] In one implementation of the first aspect, the layer 1 functions include the physical layer functions of the RAN protocol and / or the radio frequency (RF) layer functions.

[0027] In one implementation of the first aspect, the layer 2 functions include the radio link control (RLC) function and / or media access control (MAC) function of the RAN protocol.

[0028] In one implementation of the first aspect, the RU is used to acquire one or more channel quality parameters of the first bidirectional connection and determine whether the one or more channel quality parameters of the first bidirectional connection meet the threshold of the corresponding channel quality parameter.

[0029] The RU can be used to receive one or more channel quality parameters from another entity (e.g., a BBU). Alternatively, the RU can be used to acquire one or more channel quality parameters by monitoring a first bidirectional connection. Optionally, the RU can be used to acquire one or more channel quality parameters by measuring radio frequency (RF) signals or digitally converted RF signals transmitted via the first bidirectional connection.

[0030] In one implementation of the first aspect, the RU is used to establish a second bidirectional connection and, in response to receiving an establishment request message for establishing a second bidirectional connection, sends an establishment response message for establishing a second bidirectional connection.

[0031] In one implementation of the first aspect, the RU is used to deactivate the first bidirectional connection when the second bidirectional connection is activated, and in response to receiving a removal request message for deactivating the first bidirectional connection, sends a removal response message for deactivating the first bidirectional connection.

[0032] The term "deactivate" can be used as a synonym for the term "remove." The phrases "deactivate connection" and "end connection" can be used as synonyms. In this text, "establishing a connection" can mean setting up a connection. Therefore, when a connection has been established, it can mean that the connection has been established. "Activating a connection" can mean that the connection is being used effectively for its purpose, such as data transmission. Therefore, when a connection has been activated, it can mean that the connection is being used for data transmission.

[0033] In one implementation of the first aspect, the RU is used to establish a first bidirectional connection when one or more channel quality parameters of the first bidirectional connection meet the threshold of the corresponding channel quality parameters, and to send an establishment response message for establishing the first bidirectional connection in response to receiving an establishment request message for establishing the first bidirectional connection.

[0034] In one implementation of the first aspect, the RU is used to deactivate the second bidirectional connection when the first bidirectional connection is activated, and in response to receiving a removal request message for deactivating the second bidirectional connection, sends a removal response message for deactivating the second bidirectional connection.

[0035] In one implementation of the first aspect, the RU is used to communicate with the BBU according to the 5G New Radio (NR) protocol. The RU can be used to establish a second bidirectional connection with the BBU by establishing an F1 interface-based connection between the RU and the BBU, wherein the RU includes a distributed unit (DU) for managing the F1 interface-based connection. That is, the RAN protocol can be the 5G New Radio (NR) RAN protocol. The DU can be a 5G integrated access and backhaul DU (5G IAB DU).

[0036] In one implementation of the first aspect, the RU is used to establish a second bidirectional connection and, in response to receiving a remote DU establishment request message, sends a remote distributed unit (DU) establishment response message and an F1 interface establishment request message.

[0037] In one implementation of the first aspect, the RU is used to deactivate the second bidirectional connection and send an F1 interface removal request when the first bidirectional connection is activated. The RU can also be used to send a remote distributed unit (DU) removal response message in response to receiving a remote distributed unit (DU) removal request message when the second bidirectional connection is deactivated.

[0038] In one implementation of the first aspect, a threshold for the corresponding channel quality parameter of each of the one or more channel quality parameters is selected such that communication cannot be performed via the first bidirectional connection if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter. Alternatively, the threshold for the corresponding channel quality parameter of each of the one or more channel quality parameters can be selected such that communication with reduced quality is performed via the first bidirectional connection if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter.

[0039] In one implementation of the first aspect, the RU is used to wirelessly communicate with the BBU using the first bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet a second threshold of the corresponding channel quality parameter, and to limit cell performance based on the reduced capacity of the first bidirectional connection. The fact that one or more channel quality parameters of the first bidirectional connection do not meet the second threshold of the corresponding channel quality parameter can indicate the reduced capacity of the first bidirectional connection, where the channel quality of the first bidirectional connection is better than the channel quality of the first bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter.

[0040] In order to implement the RU provided in the first aspect of this disclosure, as described above, some or all of the implementations and optional features of the first aspect may be combined with each other.

[0041] A second aspect of this disclosure provides a baseband unit (BBU) for wireless communication with a radio unit (RU) according to a radio access network (RAN) protocol. The BBU establishes a first bidirectional connection with the RU, the first bidirectional connection being allocated on a first frequency band of the electromagnetic spectrum. The BBU also establishes a second bidirectional connection with the RU, the second bidirectional connection being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for radio access communication. That is, the second frequency band is used for radio access communication. The BBU is used to communicate with the RU using the second bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection is interrupted.

[0042] Since the BBU according to the second aspect is used to switch from the first bidirectional connection to the second bidirectional connection in the event that one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter or the first bidirectional connection is interrupted (i.e., fails), the BBU according to the second aspect is used to handle possible failures of the first bidirectional connection. Since the BBU is used to wirelessly communicate with the RU via the second bidirectional connection in the event that one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter or the first bidirectional connection is interrupted, the BBU is used to minimize the failure period of the bidirectional connection with the RU, for example, by ensuring the 24 / 7 availability of the bidirectional connection with the RU (either the first bidirectional connection or the second bidirectional connection).

[0043] The above description of the RU according to the first aspect is valid for the BBU according to the second aspect.

[0044] BBUs can be used in C-RAN systems. In such a C-RAN system, a BBU can be part of a BBU pool that includes multiple BBUs and can be connected to a remote RU via a fronthaul link. When a BBU is used in a C-RAN system, the fronthaul link represents the first bidirectional connection that the BBU can establish with a remote RU.

[0045] In one implementation of the second aspect, the BBU is used to establish a first bidirectional connection with the RU by implementing the layer 2 function of the RAN protocol.

[0046] In one implementation of the second aspect, the BBU is used to establish a second bidirectional connection with the RU without implementing the Layer 2 functions of the RAN protocol.

[0047] In one implementation of the second aspect, the layer 2 functions include the radio link control (RLC) function and / or media access control (MAC) function of the RAN protocol.

[0048] In one implementation of the second aspect, the BBU is used to obtain one or more channel quality parameters of the first bidirectional connection and determine whether the one or more channel quality parameters of the first bidirectional connection meet the threshold of the corresponding channel quality parameter.

[0049] The BBU can be used to receive one or more channel quality parameters from another entity. Alternatively, the BBU can be used to acquire one or more channel quality parameters by monitoring the first bidirectional connection. Optionally, the BBU can be used to acquire one or more channel quality parameters by measuring radio frequency (RF) signals or digitally converted RF signals transmitted via the first bidirectional connection.

[0050] In one implementation of the second aspect, the BBU is used to send an establishment request message for establishing a second bidirectional connection when one or more channel quality parameters of the first bidirectional connection are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, or when the first bidirectional connection is interrupted.

[0051] In one implementation of the second aspect, the BBU is used to send a removal request message to deactivate the first bidirectional connection in response to receiving an establishment response message for establishing a second bidirectional connection.

[0052] In one implementation of the second aspect, the BBU is used to send an establishment request message for establishing a first bidirectional connection, and in response to receiving an establishment response message for establishing a first bidirectional connection, communicates with the RU using the first bidirectional connection.

[0053] In one implementation of the second aspect, the BBU is used to send a removal request message to deactivate the second bidirectional connection in response to receiving an establishment response message for establishing a first bidirectional connection.

[0054] In one implementation of the second aspect, the BBU is used to communicate with the RU according to the 5G New Radio protocol and establish a second bidirectional connection with the RU by establishing a connection based on the F1 interface between the BBU and the RU. The BBU includes a central unit (CU) for managing the connection based on the F1 interface.

[0055] In one implementation of the second aspect, the BBU is used to send a remote distributed unit (DU) establishment request message when one or more channel quality parameters of the first bidirectional connection are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, and to send an F1 interface establishment response message in response to receiving the F1 interface establishment request message.

[0056] In one implementation of the second aspect, the BBU is used to respond to receiving the F1 interface removal request message, send the F1 interface removal response message, and send the remote distributed unit (DU) removal request message.

[0057] In one implementation of the second aspect, a threshold for the corresponding channel quality parameter of each of the one or more channel quality parameters is selected such that communication cannot be performed via the first bidirectional connection if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter. Alternatively, the threshold for the corresponding channel quality parameter of each of the one or more channel quality parameters can be selected such that communication with reduced quality is performed via the first bidirectional connection if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter.

[0058] The above description of the BBU according to the second aspect is valid for the RU according to the first aspect.

[0059] The second aspect, BBU, its implementation, and optional features achieve the same advantages as the first aspect, RU, its corresponding implementation, and corresponding optional features.

[0060] In order to implement the BBU provided in the second aspect of this disclosure, as described above, some or all of the implementations and optional features of the second aspect may be combined with each other.

[0061] A third aspect of this disclosure provides a method for wireless communication between a baseband unit (BBU) and a radio unit (RU) according to a radio access network (RAN) protocol. The method includes: when one or more channel quality parameters of a first bidirectional connection between the BBU and the RU do not meet a threshold value for a corresponding channel quality parameter, or when the first bidirectional connection is interrupted, using a second bidirectional connection between the BBU and the RU for communication between the BBU and the RU. The first bidirectional connection is allocated on a first frequency band of the electromagnetic spectrum. The second bidirectional connection is allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for radio access communication. That is, the second frequency band is used for radio access communication.

[0062] The method of the third aspect is correspondingly effective according to the above description of RU in the first aspect and the above description of BBU in the second aspect.

[0063] RU can be a first-party RU. BBU can be a second-party BBU.

[0064] The third aspect's method, its implementation, and optional features achieve the same advantages as the first aspect's RU, its corresponding implementation, and its corresponding optional features.

[0065] A fourth aspect of this disclosure provides a radio unit (RU) for wireless communication with baseband units (BBUs) of a BBU pool according to a radio access network (RAN) protocol. The RU is used to establish a first bidirectional connection with the BBU, the first bidirectional connection being allocated on a first frequency band of the electromagnetic spectrum. The RU is also used to establish a second bidirectional connection with the BBU, the second bidirectional connection being allocated on a second frequency band of the electromagnetic spectrum used for radio access communication. The RU is used to communicate with the BBU using the second bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection is interrupted.

[0066] The above description of the RU in the first aspect is applicable to the RU in the fourth aspect. The RU in the fourth aspect can be the RU in the first aspect. The BBU can be the BBU in the second aspect.

[0067] The fourth aspect of the RU, its implementation, and optional features achieve the same advantages as the first aspect of the RU, its corresponding implementation, and its corresponding optional features.

[0068] A fifth aspect of this disclosure provides a pool of baseband units (BBUs) for wireless communication with radio units (RUs) according to one or more radio access network (RAN) protocols. The BBUs in the pool are used to establish a first bidirectional connection with one or more RUs, the first bidirectional connection being allocated on a first frequency band of the electromagnetic spectrum. The BBUs in the pool are also used to establish a second bidirectional connection with the RUs, the second bidirectional connection being allocated on a second frequency band of the electromagnetic spectrum used for radio access communication. The BBUs in the pool are used to communicate with the RUs using the second bidirectional connection when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection is interrupted.

[0069] The above description of the BBU in the second aspect is applicable to the BBU pool in the fifth aspect. The BBUs in the BBU pool of the fifth aspect can be BBUs from the second aspect. One or more RUs can be RUs from the first or fourth aspect.

[0070] The fifth aspect, the BBU pool, its implementation, and optional features achieve the same advantages as the first aspect, the RU, its corresponding implementation, and its corresponding optional features.

[0071] It should be noted that all devices, elements, units, and components described in this application can be implemented by software or hardware elements or any combination thereof. All steps performed by the various entities described in this application, as well as the functions described for performance by the various entities, are intended to refer to the respective entities performing the corresponding steps and functions. Although in the following description of specific embodiments, the specific functions or steps to be performed by external entities are not reflected in the detailed description of the specific elements of the entity performing the specific steps or functions, those skilled in the art will understand that these methods and functions can be implemented by corresponding software or hardware elements or any combination thereof. Attached Figure Description

[0072] The above aspects and implementation methods are described below in conjunction with the accompanying drawings.

[0073] Figure 1 A pool of baseband units (BBUs) is shown, providing wireless fronthaul connectivity for multiple radio units (RUs).

[0074] Figure 2 Examples of a radio unit (RU) for wireless communication provided in embodiments of this disclosure and an example of a base band unit (BBU) for wireless communication provided in embodiments of this disclosure are shown.

[0075] Figure 3 It shows Figure 2 Examples of implementation methods for the radio unit (RU) and base band unit (BBU).

[0076] Figure 4 It shows Figure 2 Examples of implementation methods for the radio unit (RU) and base band unit (BBU).

[0077] Figure 5 It shows Figure 2Examples of implementation methods for the radio unit (RU) and base band unit (BBU).

[0078] Figure 6 It shows Figure 2 Examples of the operation of the radio unit (RU) and base band unit (BBU).

[0079] Figure 7 and Figure 8 It shows Figure 4 or Figure 5 Examples of the operation of the radio unit (RU) and base band unit (BBU).

[0080] Figure 9 It shows Figure 2 Examples of different states during wireless communication between the radio unit (RU) and the base band unit (BBU).

[0081] Figure 10 An example of a method for wireless communication between a baseband unit (BBU) and a radio unit (RU) according to a radio access network (RAN) protocol, provided by embodiments of the present disclosure, is shown.

[0082] Figure 11 Examples of radio unit (RU) for wireless communication provided in embodiments of this disclosure and examples of base band unit (BBU) pools for wireless communication provided in embodiments of this disclosure are shown.

[0083] The same elements shown in the figure are labeled with the same reference numerals and can be implemented similarly. Detailed Implementation

[0084] Figure 2 Examples of a radio unit (RU) for wireless communication provided in embodiments of this disclosure and an example of a base band unit (BBU) for wireless communication provided in embodiments of this disclosure are shown. Figure 2 RU 1 is an example of the RU provided in the first aspect of this disclosure. Therefore, according to the description of the RU in the first aspect, for... Figure 2 RU 1 is valid accordingly. Figure 2BBU 2 is an example of the BBU provided in the second aspect of this disclosure. Therefore, according to the description of the BBU in the second aspect, for... Figure 2 The corresponding BBU 2 is valid.

[0085] Figure 2 RU 1 is based on the radio access network (RAN) protocol and communicates with the BBU (e.g., Figure 2 RU 1 is a wireless communication RU for BBU 2. RU 1 is used to establish a first bidirectional connection 3a with BBU 2. The first bidirectional connection 3a is allocated on a first frequency band of the electromagnetic spectrum. RU 1 is also used to establish a second bidirectional connection 3b with BBU 2. The second bidirectional connection 3b is allocated on a second frequency band of the electromagnetic spectrum, which is used for wireless access communication. RU 1 is used to communicate with BBU 2 using the second bidirectional connection 3b when one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection 3a is interrupted.

[0086] RU 1 may include or be connected to one or more antennas for wireless communication. The one or more antennas are not limited to a specific antenna type. RU 1 may include a processor or processing circuitry (not shown) for performing, conducting, or initiating various operations of RU 1 as described herein. The processing circuitry may include hardware and / or may be software-controlled. The hardware may include analog or digital circuitry, or both. The digital circuitry may include components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. RU 1 may also include memory circuitry storing one or more instructions that can be executed by the processor or processing circuitry (specifically, under software control). For example, the memory circuitry may include a non-transitory storage medium storing executable software code that, when executed by the processor or processing circuitry, causes RU 1 to perform various operations. In one embodiment, the processing circuitry includes one or more processors and a non-transitory memory connected to one or more processors. Non-transient memory can store executable program code that, when executed by one or more processors, causes RU 1 to perform, conduct, or initiate the operations or methods described herein.

[0087] Figure 2 BBU 2 is based on the RAN protocol and communicates with RU (e.g., Figure 2 BBU 2 is used to establish a first bidirectional connection 3a with RU 1 for wireless communication. BBU 2 is used to establish a second bidirectional connection 3b with RU 1. BBU 2 is used to communicate with RU 1 using the second bidirectional connection 3b when one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection 3a is interrupted.

[0088] BBU 2 may include or be connected to one or more antennas for wireless communication. The one or more antennas are not limited to a specific antenna type. BBU 2 may include a processor or processing circuitry (not shown) for performing, conducting, or initiating various operations of BBU 2 as described herein. The processing circuitry may include hardware and / or may be software-controlled. The hardware may include analog or digital circuitry, or both. The digital circuitry may include components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. BBU 2 may also include memory circuitry storing one or more instructions that can be executed by the processor or processing circuitry (specifically, under software control). For example, the memory circuitry may include a non-transitory storage medium storing executable software code that, when executed by the processor or processing circuitry, causes BBU 2 to perform various operations. In one embodiment, the processing circuitry includes one or more processors and a non-transitory memory connected to one or more processors. Non-transient memory can store executable program code that, when executed by one or more processors, causes the BBU 2 to perform, conduct, or initiate the operations or methods described herein.

[0089] about Figure 2 Further details regarding RU 1 and BBU 2, such as optional implementations, can be found in the description of the RU according to the first aspect, the description of the BBU according to the second aspect, and... Figures 3 to 9 The description.

[0090] Figure 3 It shows Figure 2 Examples of implementation methods for the radio unit (RU) and base band unit (BBU). Figure 2 The description for Figure 3RU 1 and BBU 2 are correspondingly effective, and the main optional features and details of RU 1 and BBU 2 are described below.

[0091] like Figure 3 As shown, RU 1 may include a first communication unit 11 for establishing a first bidirectional connection 3a (i.e., a fronthaul connection) with BBU 2, and a second communication unit 12 for establishing a second bidirectional connection 3b with BBU 2. RU 1 may include a control entity 13 for activating the first communication unit 11 or the second communication unit 12, thereby establishing the first bidirectional connection 3a or the second bidirectional connection 3b with BBU 2, respectively. The control entity 13 may be or may include at least one of a processor, microprocessor, controller, microcontroller, application-specific integrated circuit (ASIC), and field-programmable gate array (FPGA). Optionally, the control entity 13 is used to monitor the quality (which may be referred to as channel quality) of the first bidirectional connection 3a by monitoring one or more channel quality parameters of the first bidirectional connection 3a.

[0092] The first communication unit 11 may include a first connection interface 11a, which is used to wirelessly communicate with the first connection interface 21 of the BBU 2 through a first bidirectional connection 3a. The second communication unit 12 may include a second connection interface 12a, which is used to wirelessly communicate with the second connection interface 22 of the BBU 2 through a second bidirectional connection 3b.

[0093] Control entity 13 can be used to disable the radio link control (RLC) function 1a and media access control (MAC) function 1b of the RAN protocol when the first bidirectional connection 3a is active. That is, RU 1 can be used to establish the first bidirectional connection 3a with BBU 2 without using RLC function 1a and MAC function 1b. RU 1 can be used to provide access to user 4 by implementing the layer 1 functions of the RAN protocol. That is, RU 1 can be used to provide access to one or more users in the RU cell by implementing the layer 1 functions of the RAN protocol. The layer 1 functions of the RAN protocol may include the physical layer (PHY) function 1c and / or radio frequency (RF) function 1d of the RAN protocol. Control entity 13 can be used to enable (i.e., activate) the RLC function 1a and / or MAC function 1b of the RAN protocol when the second bidirectional connection 3b is active. That is, RU 1 is used to establish the second bidirectional connection 3b with BBU 2 by implementing the layer 1 and layer 2 functions of the RAN protocol. Layer 2 functions of the RAN protocol may include RLC function 1a and / or MAC function 1b.

[0094] The control entity 13 may include a channel quality monitoring unit 13a for monitoring the channel quality of the first bidirectional connection 3a. The control entity 13 may include an activator 13b for enabling or disabling the RLC function 1a and MAC function 1b of the RAN protocol.

[0095] Therefore, the first communication unit 11 may include software, circuitry, and processing blocks to implement a first bidirectional connection 3a (i.e., a fronthaul connection) toward (and from) BBU 2 on the first frequency band. For example, these blocks are used to provide all the following functions of the RAN protocol: RF function 1d and low physical layer (low PHY) functions. Optionally, the aforementioned blocks of the first communication unit 11 may also be used to provide high physical layer (high PHY) functions, i.e., the aforementioned blocks of the first communication unit 11 may be used to provide RF function 1d and PHY function 1c. The low PHY and high PHY functions can be used to provide access to one or more users in the RU cell.

[0096] The second communication unit 12 may include software, circuitry, and processing blocks to implement a second bidirectional connection 3b toward (and from) BBU 2 on a second frequency band (used by the radio access system and equipment). For example, these blocks are used to provide all the following functions of the RAN protocol: RF function 1d, PHY function 1c, MAC function 1b, and RLC function 1a. PHY function 1c may include low PHY and high PHY functions. MAC function 1b may include low MAC and high MAC functions. RLC function 1a may include low RLC and high RLC functions. When the second bidirectional connection is active, the PHY, MAC, and RLC functions can be used to maintain the second bidirectional connection and provide access to one or more users in the RU cell.

[0097] like Figure 3 As shown, the second communication unit 12 can be based on at least one module that implements the RF function 1d and PHY function 1c of the RAN protocol of the first communication unit 11. The second communication unit 12 can be equipped with additional modules to implement the MAC function 1b and RLC function 1a of the RAN protocol to establish a second bidirectional connection 3b and provide radio access for one or more users in the RU cell (i.e., support one or more users to access RU 1).

[0098] Control entity 13 (e.g., activator 13b) can activate or deactivate additional modules of the second communication unit 12 based on quality changes in the first bidirectional connection 3a to implement the RAN protocol's MAC function 1b and RLC function 1a, thereby establishing the second bidirectional connection 3b depending on whether it needs to be activated or deactivated. In other words, control entity 13 manages the activation and deactivation of the RAN protocol's RLC function 1a and MAC function 1b to activate or deactivate the second bidirectional connection 3b respectively. These higher-level functions can be activated or deactivated by control entity 13 in appropriately selected time slots.

[0099] The first communication unit 11 may include a primary first bidirectional connection adaptation function unit 11b and a secondary bidirectional connection adaptation function unit 11c. These may be referred to as the "first fronthaul adaptation function" and the "second fronthaul adaptation function," respectively. The primary first bidirectional connection adaptation function unit 11b can be used to reduce fronthaul capacity by decreasing the radio access channel bandwidth for one or more users connected to cell RU1 (i.e., one or more users accessing RU1) based on the channel conditions on the first bidirectional connection. For example, the primary first bidirectional connection adaptation function unit 11b can be used to change the overall cell bandwidth, or use a smaller bandwidth part (BWP) or a smaller number of available resource blocks. The secondary bidirectional connection adaptation function unit 11c can be used to reduce fronthaul capacity by decreasing the number of multiple input multiple output (MIMO) layers (data streams) available to one or more users connected to cell RU1 based on the channel conditions on the first bidirectional connection.

[0100] RU 1 and BBU 2 can be used to perform a bidirectional signaling method between them. This method supports deactivating the first bidirectional connection 3a (i.e., the radio fronthaul connection) and alternatively activating the second bidirectional connection 3b based on the evolution of the quality of the first bidirectional connection 3a, and vice versa, deactivating the second bidirectional connection 3b and alternatively activating the first bidirectional connection 3a. An example of this method is provided below. Figure 6 , Figure 7 , Figure 8 and Figure 10 Describe it.

[0101] To monitor the quality of the first bidirectional connection 3a (e.g., when the first bidirectional connection 3a is deactivated), RU 1 and BBU 2 can be used to perform signaling (e.g., periodic signaling) between them. An example of this signaling is provided below. Figure 6 , Figure 7 and Figure 8 Describe it.

[0102] The control entity 13 of RU 1 can be used to monitor the quality of the first bidirectional connection 3a by monitoring one or more channel quality parameters of the first bidirectional connection 3a. For example, the control entity 13 can be used to monitor whether one or more channel quality parameters of the first bidirectional connection 3a meet the threshold of the corresponding channel quality parameter. The control entity 13 can be used to determine whether the first bidirectional connection 3a is interrupted (i.e., faulted), making wireless communication impossible through the first bidirectional connection 3a.

[0103] Control entity 13 can be used to deactivate at least one subset of the multiple input multiple output (MIMO) layer, bandwidth part (BWP), and resource block (RB) of the cell served by RU 1, and to implement traffic redirection actions to alleviate the cell's load when the quality of the first bidirectional connection 3a changes. Control entity 13 can also be used to prevent cell outage of the cell served by RU 1 when the first bidirectional connection 3a is completely unavailable (i.e., interrupted) by establishing a second bidirectional connection 3b allocated on a second frequency band (of the electromagnetic spectrum), the second bidirectional connection 3b being used for radio access communications (e.g., IMT services).

[0104] like Figure 3 As shown, RU 1 may be connected to or may include one or more antennas 14 for serving a cell, such as serving RAN user 4.

[0105] Figure 4 It shows Figure 2 Examples of implementation methods for the radio unit (RU) and base band unit (BBU). Figure 4 RU 1 and BBU 2 correspond to Figure 3 RU 1 and BBU 2 have additional optional features. Therefore, Figure 3 The descriptions of RU 1 and BBU 2 are for Figure 4 RU 1 and BBU 2 are correspondingly effective, and the following mainly describes... Figure 4 Additional optional features for RU 1 and BBU 2.

[0106] according to Figure 4 For example, the second bidirectional connection 3b between BBU 2 and RU 1 can be implemented using 5G NR access technology. For instance, the second bidirectional connection 3b can be implemented using the F1 interface. Therefore, according to... Figure 4 For example, BBU 2 may include a central unit (CU) 22a as a logical entity responsible for managing the F1 interface on the BBU side. CU 22a is part of the second connection interface 22 of BBU 2. That is, CU 22a of BBU 2 is used to manage the F1 interface for implementing the second bidirectional connection 3b. RU 1 may include a distributed unit (DU) 12b as a logical entity responsible for managing the F1 interface on the RU side. DU 12b is part of the second communication unit 12 of RU 1. That is, DU 12b of RU 1 is used to manage the F1 interface for implementing the second bidirectional connection 3b. In other words, according to Figure 4 For example, DU12b of RU 1 and CU 22a of BBU 2 are used to manage the F1 interface for establishing a second bidirectional connection 3b between RU 1 and BBU 2.

[0107] Figure 5 It shows Figure 2 Examples of implementation methods for the radio unit (RU) and base band unit (BBU). Figure 5 RU 1 and BBU 2 correspond to Figure 4 RU 1 and BBU 2 have additional optional features. Therefore, Figure 3 and Figure 4 The descriptions of RU 1 and BBU 2 are for Figure 5 RU 1 and BBU 2 are correspondingly effective, and the following mainly describes... Figure 5 Additional optional features for RU 1 and BBU 2.

[0108] according to Figure 5 For example, the second bidirectional connection 3b between BBU 2 and RU 1 can be implemented using 5G NR access technology. For instance, the second bidirectional connection 3b can be implemented using the F1 interface via 5G integrated access and backhaul (IAB) signaling. Therefore, according to... Figure 5 For example, BBU 2 may include a central unit (CU) 22a as a logical entity responsible for managing the F1 interface on the BBU side. That is, CU 22a of BBU 2 is used to manage the F1 interface for implementing the second bidirectional connection 3b. RU 1 may include an IAB distributed unit (IAB DU) 12b as a logical entity responsible for managing the F1 interface on the RU side. That is, IAB DU 12b of the RU is used to manage the F1 interface for implementing the second bidirectional connection 3b. The physical connection between CU 22a and IAB DU 12b of BBU 2 can be achieved through an IAB-host DU entity 22b located at BBU 2, which communicates with an IAB mobile termination (IAB-MT) entity 12c located at RU 1 via a 5G NR air interface. That is, BBU 2 may include an IAB-host DU entity 22b for communicating with the IAB-MT entity 12c of RU 1 using a 5G NR air interface. Therefore, RU 1's IAB-MT entity 12c can be used to communicate with BBU 2's IAB-host DU entity 22b via the 5G NR air interface.

[0109] Figure 6 It shows Figure 2 Examples of the operation of the radio unit (RU) and base band unit (BBU). Figure 2 The description for Figure 6 RU 1 and BBU 2 are correspondingly effective. RU and BBU can be configured as follows: Figure 3 This will be achieved as outlined.

[0110] Under normal operating conditions, it is assumed that good propagation conditions exist on the first bidirectional connection 3a (e.g., due to favorable weather). Therefore, as Figure 6 As shown, under normal operating conditions, the first bidirectional connection 3a between RU 1 and BBU 2 is active.

[0111] In alarm state, it is anticipated that propagation conditions on the first bidirectional connection 3a will be poor or the channel quality of the first bidirectional connection 3a will be insufficient for data transmission. During alarm state, the first bidirectional connection 3a can remain active, and the second bidirectional connection 3b between RU 1 and BBU 2 can be established via signaling for connection establishment (without data exchange). To this end, BBU 2 can send an establishment request message for establishing the second bidirectional connection 3b. This message... Figure 6 This is referred to as a "second connection establishment request." In other words, BBU 2 sends an establishment request message to establish a second bidirectional connection 3b when one or more channel quality parameters of the first bidirectional connection 3a are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, or when the first bidirectional connection is interrupted. Figure 6 As shown, RU 1 is used to establish a second bidirectional connection 3b, and in response to receiving an establishment request message ("second connection establishment request") for establishing the second bidirectional connection 3b, sends an establishment response message ("second connection establishment response") for establishing the second bidirectional connection 3b.

[0112] Therefore, in an emergency, if the propagation conditions on the first bidirectional connection 3a are poor (e.g., due to severe weather), causing the first bidirectional connection 3a to be interrupted or its channel quality to be insufficient for data transmission, the first bidirectional connection 3a can be deactivated, and the second bidirectional connection 3b can be activated to transmit data between RU 1 and BBU 2. For this purpose, as follows... Figure 6As shown, BBU 2 is used to send a removal request message ("first connection removal request") to deactivate the first bidirectional connection 3a in response to receiving an establishment response message for establishing a second bidirectional connection 3b ("second connection establishment response"). RU 1 is used to deactivate the first bidirectional connection 3a when the second bidirectional connection 3b is activated, and in response to receiving a removal request message ("first connection removal request") to deactivate the first bidirectional connection 3a, it sends a removal response message ("first connection removal response") to deactivate the first bidirectional connection 3a.

[0113] During the fronthaul link status check, BBU 2 can periodically check the status of the first bidirectional connection 3a via signaling messages for re-establishing the first bidirectional connection 3a. For this purpose, as follows... Figure 6 As shown, BBU 2 is used to send an establishment request message (“First Connection Establishment Request”) for establishing a first bidirectional connection 3a. BBU 2 can be used to send this establishment request message periodically. RU 1 is used to establish the first bidirectional connection 3a when one or more channel quality parameters of the first bidirectional connection 3a meet the threshold of the corresponding channel quality parameter (e.g., when the propagation conditions on the first bidirectional connection 3a are sufficient for data transmission), and in response to receiving the establishment request message (“First Connection Establishment Request”) for establishing the first bidirectional connection 3a, sends an establishment response message (“First Connection Establishment Response”) for establishing the first bidirectional connection 3a. BBU 2 is used to communicate with RU 1 using the first bidirectional connection 3a in response to receiving the establishment response message (“First Connection Establishment Response”) for establishing the first bidirectional connection 3a.

[0114] With the fronthaul link reactivated, propagation conditions on the first bidirectional connection 3a are favorable (e.g., due to favorable weather). Therefore, as Figure 6 As shown, the first bidirectional connection 3a is activated. The second bidirectional connection 3b is then activated via appropriate signaling messages. These signaling messages can be sent through either the first bidirectional connection 3a or the second bidirectional connection 3b. To this end, BBU 2, in response to receiving an establishment response message for establishing the first bidirectional connection 3a (“first connection establishment response”), sends a removal request message (“second connection removal request”) for deactivating the second bidirectional connection 3b. If the first bidirectional connection 3a is activated, RU 1, in response to receiving a removal request message (“second connection removal request”) for deactivating the second bidirectional connection 3b, sends a removal response message (“second connection removal response”) for deactivating the second bidirectional connection 3b.

[0115] The establishment request message (“Second Connection Establishment Request”) for establishing the second bidirectional connection 3b, the establishment response message (“Second Connection Establishment Response”) for establishing the second bidirectional connection 3b, the removal request message (“First Connection Removal Request”) for deactivating the first bidirectional connection 3a, the removal response message (“First Connection Removal Response”) for deactivating the first bidirectional connection 3a, the removal request message (“Second Connection Removal Request”) for deactivating the second bidirectional connection 3b, and the removal response message (“Second Connection Removal Response”) for deactivating the second bidirectional connection 3b can be encoded by the first bidirectional connection 3a in an optional field of a data packet unit defined by the fronthaul protocol used (e.g., eCPRI, Open Fronthaul, etc.). The abbreviation “eCPRI” stands for “Enhanced General Public Radio Interface”.

[0116] Figure 7 and Figure 8 It shows Figure 4 or Figure 5 Examples of the operation of the radio unit (RU) and base band unit (BBU). Figure 4 and Figure 5 The description for Figure 7 and Figure 8 RU 1 and BBU 2 are valid accordingly.

[0117] In normal operating condition (e.g.) Figure 7 As shown below, assume that there are favorable propagation conditions on the first bidirectional connection 3a (e.g., due to good weather). Therefore, as Figure 7 As shown, under normal operating conditions, the first bidirectional connection 3a between RU 1 and BBU 2 is active.

[0118] In alarm state (such as) Figure 7As shown, under the condition that the propagation conditions on the first bidirectional connection 3a are expected to be poor or the channel quality of the first bidirectional connection 3a is insufficient for data transmission. During the alarm state, the first bidirectional connection 3a can remain active and can establish a second bidirectional connection 3b (without exchanging data) between RU 1 and BBU 2 using 5G NR access technology through signaling for establishing a DU on the RU side and standardized signaling on the F1 interface. For this purpose, BBU 2 can send a remote distributed unit (DU) establishment request message (“Remote DU Establishment Request”). That is, BBU 2 sends a remote DU establishment request message (“Remote DU Establishment Request”) when one or more channel quality parameters of the first bidirectional connection are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, and sends an F1 interface establishment response message (“F1 Establishment Response”) in response to receiving an F1 interface establishment request (“F1 Establishment Request”). Figure 7 As shown, RU 1 is used to establish a second bidirectional connection 3b, and in response to receiving a remote distributed unit (DU) establishment request message (“Remote DU Establishment Request”), sends a remote DU establishment response message (“Remote DU Establishment Response”) and an F1 interface establishment request message (“F1 Establishment Request”).

[0119] Therefore, in an emergency (such as Figure 7 As shown, if poor propagation conditions on the first bidirectional connection 3a (e.g., due to severe weather) cause the first bidirectional connection 3a to be interrupted or its channel quality to be insufficient for data transmission, the first bidirectional connection 3a can be deactivated, and the second bidirectional connection 3b can be activated using 5G NR access technology to transmit data between RU 1 and BBU 2. The complete activation of the second bidirectional connection 3b can be indicated and completed by the central unit (CU) of BBU 2 via standardized F1 signaling. Figure 7 As shown, in order to deactivate the first bidirectional connection 3a, in alarm state, BBU 2 is used to send a removal request message ("first connection removal request") for deactivating the first bidirectional connection 3a. RU 1 is used to deactivate the first bidirectional connection 3a when the second bidirectional connection 3b is activated, and in response to receiving the removal request message ("first connection removal request") for deactivating the first bidirectional connection 3a, sends a removal response message ("first connection removal response") for deactivating the first bidirectional connection 3a.

[0120] Check the status of the fronthaul link (e.g.) Figure 8During the period shown, BBU 2 can periodically check the status of the first bidirectional connection 3a by means of signaling messages for re-establishing the first bidirectional connection 3a. For this purpose, as shown... Figure 8 As shown, BBU 2 can be used to send an establishment request message (“first connection establishment request”) for establishing a first bidirectional connection 3a. BBU 2 can be used to send this establishment request message periodically. When one or more channel quality parameters of the first bidirectional connection 3a meet a threshold of the corresponding channel quality parameter (e.g., when propagation conditions on the first bidirectional connection 3a are sufficient for data transmission), RU 1 establishes the first bidirectional connection 3a and, in response to receiving the establishment request message (“first connection establishment request”), sends an establishment response message (“first connection establishment response”) for establishing the first bidirectional connection 3a. BBU 2, in response to receiving the establishment response message (“first connection establishment response”), communicates with RU 1 using the first bidirectional connection 3a.

[0121] In the state of fronthaul link reactivation (e.g.) Figure 8 As shown, propagation conditions on the first bidirectional connection 3a are good (e.g., due to good weather). Propagation conditions on the first bidirectional connection 3a can be good if one or more channel quality parameters of the first bidirectional connection 3a meet the threshold of the corresponding channel quality parameter (e.g., if propagation conditions on the first bidirectional connection 3a are sufficient for data transmission). Therefore, as... Figure 8 As shown, the first bidirectional connection 3a is activated. The second bidirectional connection 3b, using 5G NR access technology and the DU on the RU side, is deactivated via appropriate signaling messages. For this purpose, BBU 2, in response to receiving an F1 interface removal request (“F1 removal request”), sends an F1 interface removal response message (“F1 removal response”) and a remote distributed unit (DU) removal request message (“remote DU removal request”). RU 1, when the first bidirectional connection 3a is activated, deactivates the second bidirectional connection 3b and sends an F1 interface removal request message (“F1 removal request”). When the second bidirectional connection 3b is deactivated, RU 1, in response to receiving a remote distributed unit (DU) removal request message (“remote DU removal request”), sends a remote distributed unit (DU) removal response message (“remote DU removal response”).

[0122] Therefore, as about Figure 7 and Figure 8As outlined, the F1 signaling interface (F1-C) of the 5GF1AP (F1 Application Protocol) used in 5G NR to manage the F1 interface between the CU and DU can be supplemented with additional signaling messages to manage the activation / deactivation of the first bidirectional connection 3a. This new signaling, namely the establishment request message (“First Connection Establishment Request”) and the establishment response message (“First Connection Establishment Response”) for establishing the first bidirectional connection 3a, can be encoded in the appropriate area of ​​the F1-C. The F1 interface establishment request message (“F1 Establishment Request”), F1 interface establishment response message (“F1 Establishment Response”), F1 interface removal request message (“F1 Removal Request”), and F1 interface removal response message (“F1 Removal Response”) can be standardized within the 5G F1AP.

[0123] The remote distributed unit (DU) establishment request message (“Remote DU Establishment Request”), the remote distributed unit (DU) establishment response message (“Remote DU Establishment Response”), the removal request message for deactivating the first bidirectional connection 3a (“First Connection Removal Request”), and the removal response message for deactivating the first bidirectional connection 3a (“First Connection Removal Response”) can be encoded by the first bidirectional connection 3a in an optional field of the packet unit defined by the fronthaul protocol used (e.g., eCPRI, Open Fronthaul, etc.).

[0124] Figure 9 It shows Figure 2 Examples of different states during wireless communication between the radio unit (RU) and the base band unit (BBU). Figure 2 The description for Figure 9 RU 1 and BBU 2 are valid accordingly. Figure 9 RU 1 and BBU 2 can be Figure 3 , Figure 4 and Figure 5 RU 1 and BBU 2 of any of the graphs. In this case, Figure 3 , Figure 4 or Figure 5 The description is valid accordingly.

[0125] According to the first assumption, i.e., Case 1, the first bidirectional connection 3a between RU 1 and BBU 2 has full quality and can support the full performance of the cell (e.g., high resource block (RB) occupancy, high number of multiple input multiple output (MIMO) layers, etc.). That is, in Case 1, the first bidirectional connection 3a between RU 1 and BBU 2 is active. Therefore, in Case 1, due to the good quality of the first bidirectional connection 3a, RU 1 can fully serve its cell. This supports the full performance of the cell. In Case 1, regarding the establishment of the second bidirectional connection 3b, RU 1, for example, its control entity, may take no action other than continuously monitoring the channel quality of the first bidirectional connection 3a.

[0126] According to the second assumption, i.e., scenario 2, the channel quality of the first bidirectional connection 3a is degraded compared to scenario 1. For example, the maximum bit rate achievable for the target bit error rate (BER), a channel quality parameter of the first bidirectional connection 3a, has decreased compared to scenario 1. This could be due to light rain and / or fog. In scenario 2, RU 1 (e.g., its control entity) can be used to actively limit cell performance based on the reduced available capacity of the first bidirectional connection 3a (i.e., reduced fronthaul capacity). For example, RU 1 (e.g., its control entity) can achieve this by deactivating at least one subset of the MIMO layer, bandwidth part (BWP), and RB, and by implementing traffic steering actions to alleviate the burden on the cell. These actions support limiting the overall fronthaul capacity requirements.

[0127] In other words, RU 1 can be used to wirelessly communicate with BBU 2 using the first bidirectional connection 3a when one or more channel quality parameters of the first bidirectional connection 3a do not meet the second threshold of the corresponding channel quality parameter (i.e., case 2 occurs), and to limit cell performance based on the reduced capacity of the first bidirectional connection 3a. The fact that one or more channel quality parameters of the first bidirectional connection 3a do not meet the second threshold of the corresponding channel quality parameter can indicate the reduced capacity of the first bidirectional connection 3a, where the channel quality of the first bidirectional connection 3a is better than the channel quality of the first bidirectional connection 3a when one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter. When one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter, the channel quality of the first bidirectional connection 3a can correspond to... Figure 9 Case 3.

[0128] According to the third assumption, scenario 3, the channel quality of the first bidirectional connection 3a has degraded to the point of causing a complete link failure (i.e., the first bidirectional connection 3a is interrupted). In response, RU 1 (e.g., its control entity) can activate previously dormant Layer 2 functions in the RAN protocol stack (e.g., the local RAN protocol stack). That is, RU 1 is not using Layer 2 functions for the first bidirectional connection 3a. These Layer 2 functions may include MAC functions and / or RLC functions. Furthermore, RU 1 (e.g., its control entity) can activate (i.e. establish) a second bidirectional connection 3b between RU 1 and BBU 2.

[0129] The second bidirectional connection 3b can provide bidirectional transmission of higher-level protocol data units (PDUs) using radio access technology, characterized by having lower capacity requirements compared to the first bidirectional connection 3a. RU 1 can be used to optimally manage the coexistence of the second bidirectional connection 3b with the transmission and reception of radio access users on the second frequency band using radio resource management techniques (e.g., through optimized frequency division multiple access considering the actual throughput requirements of network nodes).

[0130] Optionally, RU 1 can be used to deactivate the first bidirectional connection 3a and activate the second bidirectional connection 3b, even if the first bidirectional connection 3a is not completely interrupted. RU 1 can be used to do this when the channel quality of the first bidirectional connection 3a degrades to the point that the second bidirectional connection 3b is considered more efficient and capable of providing higher capacity to users in the cell served by RU 1.

[0131] In other words, a threshold for the corresponding channel quality parameter for each of one or more channel quality parameters can be selected such that communication is impossible via the first bidirectional connection 3a if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter. In this case, it can be assumed that a channel quality parameter that does not meet the threshold of the corresponding channel quality parameter represents an interruption of the first bidirectional connection 3a (i.e., this corresponds to...). Figure 9 (Scenario 3). Therefore, RU 1 can activate the second bidirectional connection 3b if the first bidirectional connection 3a is interrupted.

[0132] Alternatively, a threshold for the corresponding channel quality parameter for each of the one or more channel quality parameters is selected such that communication with reduced quality can be performed via the first bidirectional connection 3a if the channel quality parameter does not meet the threshold of the corresponding channel quality parameter. Therefore, RU 1 can deactivate the first bidirectional connection 3a and activate the second bidirectional connection 3b if wireless communication via the first bidirectional connection 3a is still possible, but the quality of the first bidirectional connection 3a is reduced, making wireless communication via the second bidirectional connection 3b more desirable (e.g., more efficient).

[0133] Figure 10 An example of a method for wireless communication between a baseband unit (BBU) and a radio unit (RU) according to a radio access network (RAN) protocol, provided by embodiments of the present disclosure, is shown. Figure 10 The method is an example of the method provided in the third aspect of this disclosure. Therefore, according to the description of the method in the third aspect, for Figure 10 The method is effective accordingly.

[0134] Figure 10 This method is used for wireless communication between a BBU and a RU according to a radio access network (RAN) protocol. The BBU and RU can be respectively... Figures 1 to 9 The BBU and RU of any graph in the dataset. Figure 10 As shown, the method includes step S100: If one or more channel quality parameters of the first bidirectional connection between the BBU and the RU do not meet the threshold of the corresponding channel quality parameter, or if the first bidirectional connection is interrupted, communication between the BBU and the RU is performed using a second bidirectional connection. The first bidirectional connection is allocated on a first frequency band of the electromagnetic spectrum. The second bidirectional connection is allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication.

[0135] Figure 11 Examples of radio unit (RU) for wireless communication provided in embodiments of this disclosure and examples of base band unit (BBU) pools for wireless communication provided in embodiments of this disclosure are shown. Figure 11 RU 1 is an example of the RU provided in the fourth aspect of this disclosure. Therefore, according to the description of the RU in the fourth aspect, for... Figure 11 RU 1 is valid accordingly. Figure 11 BBU pool 20 is an example of a BBU pool provided in the fifth aspect of this disclosure. Therefore, according to the description of the BBU pool in the fifth aspect, for Figure 11 The corresponding BBU pool 20 is valid.

[0136] Figure 11 Each RU 1 in the RU 1 is an RU used for wireless communication with BBU 2 in BBU pool 20 according to the radio access network (RAN) protocol. Each RU 1 is used to establish a first bidirectional connection 3a with BBU 2, the first bidirectional connection 3a being allocated on a first frequency band of the electromagnetic spectrum. Each RU 1 is used to establish a second bidirectional connection 3b with BBU 2. The second bidirectional connection 3b is allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for radio access communication. Each RU 1 is used to communicate with BBU 2 using the second bidirectional connection 3b if one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter, or if the first bidirectional connection 3a is interrupted.

[0137] Figure 11 BBU pool 20 is a BBU pool used for wireless communication with one or more RUs according to the radio access network (RAN) protocol. BBU 2 of BBU pool 20 is used to establish a first bidirectional connection 3a with RU 1 of one or more RUs 1. BBU 2 of BBU pool 20 is used to establish a second bidirectional connection 3b with RU 1. BBU 2 of BBU pool 20 is used to communicate with RU 1 using the second bidirectional connection 3b when one or more channel quality parameters of the first bidirectional connection 3a do not meet the threshold of the corresponding channel quality parameter, or when the first bidirectional connection 3a is interrupted. The above can be valid for each BBU 2 of BBU pool 20.

[0138] Figure 11 Each RU 1 can be Figures 1 to 9 RU 1 in any graph. Each BBU 2 in BBU pool 20 can be Figures 1 to 9 BBU 2 for any graph in the dataset.

[0139] according to Figure 11 In the example, there are two RU1s. This number is just an example and can vary. That is, there can be one or more RU1s. Figure 11For example, BBU pool 20 includes two BBUs 2. This number is only an example and can vary. That is, BBU pool 20 may include two or more BBUs 2. Any of the multiple BBUs 2 can be used to wirelessly communicate with any of one or more RUs 1 via a first bidirectional connection 3a or a second bidirectional connection 3b according to the RAN protocol. Any of the one or more RUs 1 can be used to wirelessly communicate with any of the multiple BBUs 2 in BBU pool 20 according to the RAN protocol.

[0140] Figure 11 An exemplary illustration is shown as the first RU 1 (e.g. Figure 11 (as shown on the left) and the second RU 1 (as shown on the left) Figure 11 (As shown on the right), the first RU 1 is used to connect with the first BBU 2 of BBU pool 20 according to the RAN protocol (as shown on the right). Figure 11 (As shown on the left) for wireless communication, the second RU 1 is used to communicate with the second BBU 2 (as shown on the left) of BBU pool 20 according to the RAN protocol. Figure 11 (As shown on the right) Wireless communication is performed. This is merely an example and does not limit this disclosure.

[0141] One or more RU 1 and BBU pool 20 can form a wireless communication system. They can form a wireless communication network. One or more RU 1 and BBU pool 20 can form a C-RAN system. One or more first bidirectional connections 3a are one or more fronthaul links.

[0142] The communication devices disclosed herein (e.g., the RU of the first aspect, the BBU of the second aspect, the RU of the fourth aspect, and the BBU in the BBU pool of the fifth aspect) can be used in a C-RAN system. In this case, any communication device of the present disclosure can establish a first bidirectional connection as a fronthaul link.

[0143] This disclosure has been described in conjunction with various embodiments and implementations as examples. However, those skilled in the art, through practice of the claimed matters and by studying the accompanying drawings, this disclosure, and the independent claims, will understand and derive other variations. In the claims and the description, the word "comprising" does not exclude other elements or steps, and "a" does not exclude a plurality. A single element or other unit may fulfill the function of several entities or items listed in the claims. The listing of certain measures in dissimilar dependent claims does not imply that a combination of these measures cannot be effectively used.

Claims

1. A radio frequency unit RU (1) for wireless communication with a baseband unit (BBU) (2) according to a radio access network (RAN) protocol, characterized in that, The RU(1) is used for: - Establish a first bidirectional connection (3a) with the BBU (2), the first bidirectional connection (3a) being allocated on a first frequency band of the electromagnetic spectrum. - Establish a second bidirectional connection (3b) with the BBU (2), the second bidirectional connection (3b) being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication. - In the event that one or more channel quality parameters of the first bidirectional connection (3a) do not meet the threshold of the corresponding channel quality parameter, or in the event that the first bidirectional connection (3a) is interrupted, the second bidirectional connection (3b) is used to communicate with the BBU (2).

2. The RU (1) according to claim 1, characterized in that, - The RU (1) is used to establish the first bidirectional connection (3a) with the BBU (2) and provide access to users by implementing the Layer 1 function of the RAN protocol.

3. The RU (1) according to claim 1 or 2, characterized in that, - The RU (1) is used to establish the second bidirectional connection (3b) with the BBU (2) by implementing the layer 1 and layer 2 functions of the RAN protocol.

4. The RU (1) according to claim 3, characterized in that, - The RU (1) is used to activate the layer 2 function of the RAN protocol in the event of an interruption of the first bidirectional connection (3a) to establish the second bidirectional connection (3b) with the BBU (2).

5. The RU (1) according to any one of claims 2 to 4, characterized in that, - The Layer 1 functions include the physical layer functions (1c) and / or the radio frequency (RF) layer functions (1d) of the RAN protocol.

6. The RU (1) according to any one of claims 3 to 5, characterized in that, - The Layer 2 functions include the Radio Link Control (RLC) function (1a) and / or the Media Access Control (MAC) function (1b) of the RAN protocol.

7. The RU (1) according to any one of the preceding claims, characterized in that, The RU(1) is used for: - Obtain one or more channel quality parameters of the first bidirectional connection (3a). - Determine whether one or more channel quality parameters of the first bidirectional connection (3a) meet the threshold of the corresponding channel quality parameter.

8. The RU (1) according to any one of the preceding claims, characterized in that, - The RU (1) is used to establish the second bidirectional connection (3b) and, in response to receiving the establishment request message for establishing the second bidirectional connection, sends an establishment response message for establishing the second bidirectional connection (3b).

9. The RU (1) according to any one of the preceding claims, characterized in that, - The RU (1) is used to deactivate the first bidirectional connection (3a) when the second bidirectional connection (3b) is activated, and in response to receiving a removal request message for deactivating the first bidirectional connection (3a), sends a removal response message for deactivating the first bidirectional connection (3a).

10. The RU (1) according to any one of the preceding claims, characterized in that, The RU(1) is used for: - If one or more channel quality parameters of the first bidirectional connection (3a) meet the threshold of the corresponding channel quality parameter, the first bidirectional connection (3a) is established, and in response to receiving the establishment request message for establishing the first bidirectional connection (3a), an establishment response message for establishing the first bidirectional connection (3a) is sent.

11. The RU (1) according to any one of the preceding claims, characterized in that, The RU(1) is used for: - When the first bidirectional connection (3a) is activated, the second bidirectional connection (3b) is deactivated, and in response to receiving a removal request message for deactivating the second bidirectional connection (3b), a removal response message for deactivating the second bidirectional connection (3b) is sent.

12. The RU (1) according to any one of the preceding claims, characterized in that, The RU(1) is used for: - Communicate with the BBU (2) according to the 5G New Radio protocol. -A second bidirectional connection (3b) is established with the BBU by establishing an F1 interface-based connection between the RU (1) and the BBU (2), wherein, - The RU (1) includes a distributed unit DU (12b) for managing the connection based on the F1 interface.

13. The RU (1) according to claim 12, characterized in that, - The RU (1) is used to establish the second bidirectional connection (3b) and, in response to receiving the remote DU establishment request message, sends a remote distributed unit DU establishment response message and an F1 interface establishment request message.

14. The RU (1) according to claim 12 or 13, characterized in that, The RU(1) is used for: -If the first bidirectional connection (3a) is activated, deactivate the second bidirectional connection (3b) and send an F1 interface removal request message. - In the event that the second bidirectional connection (3b) is deactivated, in response to receiving the remote distributed unit (DU) removal request message, a remote distributed unit (DU) removal response message is sent.

15. The RU (1) according to any one of the preceding claims, characterized in that, A threshold for the corresponding channel quality parameter for each of the one or more channel quality parameters is selected such that: -If the channel quality parameters do not meet the threshold of the corresponding channel quality parameters, communication cannot be performed through the first bidirectional connection (3a), or - If the channel quality parameter does not meet the threshold of the corresponding channel quality parameter, communication can be carried out with reduced quality through the first bidirectional connection (3a).

16. The RU (1) according to any one of the preceding claims, characterized in that, The RU (1) is used to: when one or more channel quality parameters of the first bidirectional connection (3a) do not meet the second threshold of the corresponding channel quality parameter, - Use the first bidirectional connection (3a) to communicate wirelessly with the BBU (2). -Based on the reduced capacity-limited cell performance of the first bidirectional connection (3a); wherein, - The reduced capacity of the first bidirectional connection (3a) is indicated by the fact that one or more channel quality parameters of the first bidirectional connection do not meet the second threshold of the corresponding channel quality parameter. - The channel quality of the first bidirectional connection (3a) is better than the channel quality of the first bidirectional connection (3a) when one or more channel quality parameters of the first bidirectional connection do not meet the threshold of the corresponding channel quality parameter.

17. A baseband unit (BBU) (2) for wireless communication with a radio frequency unit (RU) (1) according to a radio access network (RAN) protocol, characterized in that, The BBU (2) is used for: - Establish a first bidirectional connection (3a) with the RU (1), the first bidirectional connection (3a) being allocated on a first frequency band of the electromagnetic spectrum. - Establish a second bidirectional connection (3b) with the RU (1), the second bidirectional connection (3b) being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication. - In the event that one or more channel quality parameters of the first bidirectional connection (3a) do not meet the threshold of the corresponding channel quality parameter, or in the event that the first bidirectional connection (3a) is interrupted, the second bidirectional connection (3b) is used to communicate with the RU (1).

18. The BBU (2) according to claim 17, characterized in that, - The BBU (2) is used to establish the first bidirectional connection (3a) with the RU (1) by implementing the layer 2 function of the RAN protocol.

19. The BBU (2) according to claim 17 or 18, characterized in that, - The BBU (2) is used to establish the second bidirectional connection (3b) with the RU (1) without implementing the layer 2 function of the RAN protocol.

20. The BBU (2) according to claim 18 or 19, characterized in that, - The Layer 2 functions include the Radio Link Control (RLC) function (1a) and / or the Media Access Control (MAC) function (1b) of the RAN protocol.

21. The BBU (2) according to any one of claims 17 to 20, characterized in that, The BBU (2) is used for: - Obtain one or more channel quality parameters of the first bidirectional connection (3a). - Determine whether one or more channel quality parameters of the first bidirectional connection (3a) meet the threshold of the corresponding channel quality parameter.

22. The BBU (2) according to any one of claims 17 to 21, characterized in that, - The BBU (2) is used to send an establishment request message for establishing the second bidirectional connection (3b) when one or more channel quality parameters of the first bidirectional connection (3a) are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, or when the first bidirectional connection (3a) is interrupted.

23. The BBU (2) according to any one of claims 17 to 22, characterized in that, - The BBU (2) is used to send a removal request message to deactivate the first bidirectional connection (3a) in response to receiving an establishment response message for establishing the second bidirectional connection (3b).

24. The BBU (2) according to any one of claims 17 to 23, characterized in that, The BBU (2) is used for: - Send an establishment request message to establish the first bidirectional connection (3a). - In response to receiving an establishment response message for establishing the first bidirectional connection (3a), communicate with the RU (1) using the first bidirectional connection (3a).

25. The BBU (2) according to any one of claims 17 to 24, characterized in that, The BBU (2) is used for: - In response to receiving an establishment response message for establishing the first bidirectional connection (3a), a removal request message for deactivating the second bidirectional connection (3b) is sent.

26. The BBU (2) according to any one of claims 17 to 25, characterized in that, The BBU (2) is used for: - Communicate with the RU(1) according to the 5G New Radio protocol. -A second bidirectional connection (3b) is established with the RU (1) by establishing an F1 interface-based connection between the BBU (2) and the RU (1), wherein, - The BBU (2) includes a centralized unit CU (22a) for managing the F1 interface-based connection.

27. The BBU (2) according to claim 26, characterized in that, The BBU (2) is used for: - If one or more channel quality parameters of the first bidirectional connection (3a) are predicted to no longer meet the threshold of the corresponding channel quality parameter within a specific time period, a remote distributed unit (DU) establishment request message is sent. - In response to receiving the F1 interface establishment request message, send an F1 interface establishment response message.

28. The BBU (2) according to claim 26 or 27, characterized in that, The BBU (2) is used for: - In response to receiving the F1 interface removal request message, send the F1 interface removal response message and send the remote distributed unit (DU) removal request message.

29. The BBU (2) according to any one of claims 17 to 28, characterized in that, A threshold for the corresponding channel quality parameter for each of the one or more channel quality parameters is selected such that: -If the channel quality parameters do not meet the threshold of the corresponding channel quality parameters, communication cannot be performed through the first bidirectional connection (3a), or - If the channel quality parameter does not meet the threshold of the corresponding channel quality parameter, communication can be carried out with reduced quality through the first bidirectional connection (3a).

30. A method for wireless communication between a baseband unit (BBU) and a radio frequency unit (RU) according to a radio access network (RAN) protocol, characterized in that, The method includes: - If one or more channel quality parameters of the first bidirectional connection between the BBU and the RU do not meet the threshold of the corresponding channel quality parameter, or if the first bidirectional connection is interrupted, communication between the BBU and the RU is performed using the second bidirectional connection between the BBU and the RU in (S100), wherein, - The first bidirectional connection is allocated on a first frequency band of the electromagnetic spectrum. - The second bidirectional connection is allocated on a second frequency band of the electromagnetic spectrum, which is used for wireless access communication.

31. A radio frequency unit RU (1) for wireless communication with BBU (2) in a baseband unit BBU pool (20) according to a radio access network (RAN) protocol, characterized in that, The RU(1) is used for: - Establish a first bidirectional connection (3a) with the BBU (2), the first bidirectional connection (3a) being allocated on a first frequency band of the electromagnetic spectrum. - Establish a second bidirectional connection (3b) with the BBU (2), the second bidirectional connection (3b) being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication. - In the event that one or more channel quality parameters of the first bidirectional connection (3a) do not meet the threshold of the corresponding channel quality parameter, or in the event that the first bidirectional connection (3a) is interrupted, the second bidirectional connection (3b) is used to communicate with the BBU (2).

32. A baseband unit (BBU) pool (20) for wireless communication with one or more radio frequency units (RUs) according to a radio access network (RAN) protocol, characterized in that, The BBU (2) in the BBU pool (20) is used for: - Establish a first bidirectional connection (3a) with one or more of the RUs (1), the first bidirectional connection (3a) being allocated on a first frequency band of the electromagnetic spectrum. - Establish a second bidirectional connection (3b) with the RU (1), the second bidirectional connection (3b) being allocated on a second frequency band of the electromagnetic spectrum, the second frequency band being used for wireless access communication. - In the event that one or more channel quality parameters of the first bidirectional connection (3a) do not meet the threshold of the corresponding channel quality parameter, or in the event that the first bidirectional connection (3a) is interrupted, the second bidirectional connection (3b) is used to communicate with the RU (1).

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