A CPRI ring network communication fault self-healing method and system

Abstract

The present disclosure relates to a CPRI ring network communication fault self-healing method and system, the method comprising: in a CPRI ring network link having an EU and several RUs, defining the CPRI ring network link as having a normal state, a reverse state and a transition state; during the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and first configuration data to the RU directly connected thereto, and the auxiliary optical port sends downlink data and second configuration data to the RU directly connected thereto; detecting the states of the uplink port and downlink port of the RU in real time, and controlling the CPRI ring network link to switch states according to the states of the uplink port and downlink port, and when the CPRI ring network link switches to the normal state or the reverse state, delay compensation is performed on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information and the reverse delay compensation information. The system is used to execute the above method. The present disclosure has the advantages of fast data conversion speed, efficient delay compensation and stable state switching.

Description

Technical Field

[0001] The present disclosure relates to the technical field of 5G communications, and in particular to a CPRI ring network communication fault self-healing method and system. Background Art

[0002] As the fifth generation international standard for mobile communications, NR has been widely promoted and applied around the world. The 5G indoor distribution system mainly includes the core network, micro-cell base stations, radio frequency extension units (EUs), and radio frequency remote units (RUs). Under the EU, several cascaded EUs and RUs are usually connected, and the cascaded EUs continue to connect EUs or RUs. The underlying connection between them is connected through optical fiber, and the communication protocol carried is generally the CPRI protocol. Their network topology is commonly a star connection between EUs and RUs, and a chain connection between RUs.

[0003] In special application areas such as high-speed rail and coal mines, where the robustness of the network is particularly high, a ring connection structure is generally used to improve reliability, that is, several RUs are cascaded end to end under the EU main optical port, and the tail of the last cascaded RU is connected to the auxiliary optical port of the EU, so that a ring closed loop connection of RUs is formed at both ends of the main and auxiliary ports of the EU. When the optical path at a certain RU in the loop fails, the EU auxiliary optical port will start data transmission to ensure the normal data transmission of all RUs connected to the back end of the breakpoint. At this time, the loop will be transformed into a dual-chain network structure.

[0004] The speed and accuracy of the RU optical port fault detection and connection switching self-healing of the ring network system determine the network signal transmission performance. The conventional method for breakpoint fault detection and self-healing is to have the RU detect the fault and report the fault location to the EU port through the C&M channel. After the EU conducts unified arbitration, it sends the new topology structure and fiber propagation delay compensation information to each corresponding level of RU, and then starts the transmission of the auxiliary optical port link. The entire ring network self-healing process is slow, generally taking more than tens of seconds, resulting in short-term disconnection of 5G services, seriously affecting the network performance experience. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention aims to provide a CPRI ring network communication fault self-healing method and system. The present invention has the advantages of fast data conversion speed, efficient delay compensation and stable state switching.

[0006] A CPRI ring network communication fault self-healing method disclosed in the present disclosure includes:

[0007] In a CPRI ring network link having an EU and a plurality of RUs, the CPRI ring network link is defined to have a normal state, a reverse state and a transition state;

[0008] In the normal state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link to RUs of each level in sequence and then back to the auxiliary optical port of the EU;

[0009] In the reverse state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link and transmitted to the RU located on one side of the broken link. At the same time, data is also transmitted from the auxiliary optical port of the EU along the reverse direction of the CPRI ring network link and transmitted to the RU located on the other side of the broken link.

[0010] The transition state serves as an intermediate state between the normal state and the reverse state;

[0011] During the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and first configuration data to the RU directly connected thereto, and the auxiliary optical port sends downlink data and second configuration data to the RU directly connected thereto, wherein the first configuration data includes the topology ID assigned by the EU to the RU and the forward delay compensation information of each RU, and the second configuration data includes the reverse delay compensation information of each RU;

[0012] After receiving the downlink data, the first configuration data and the second configuration data, the RU saves the data and forwards them to other RUs step by step after modifying the topology ID;

[0013] The status of the uplink port and the downlink port of the RU is detected in real time, and the CPRI ring network link is controlled to switch the state according to the status of the uplink port and the downlink port. When the CPRI ring network link is switched to the normal state or the reverse state, delay compensation is performed on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information, and the reverse delay compensation information.

[0014] Preferably, according to the states of the uplink port and the downlink port, controlling the CPRI ring network link to switch the state is specifically as follows:

[0015] When the CPRI ring network link is in a transition state, if the uplink port of each RU is successfully linked, and the topology IDs received by the RU in several consecutive CPRI superframes are not all 0, the CPRI ring network link is switched to a normal state; if the downlink port of each RU is successfully linked, and the uplink port of each RU fails to establish a link or the uplink port is successfully linked but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a reverse state;

[0016] When the CPRI ring network link is in a normal state, if the uplink port of each RU fails to establish a link or the uplink port successfully establishes a link but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a reverse state;

[0017] When the CPRI ring network link is in a reversal state, if the uplink port of each RU is successfully linked, and the topology IDs received by the RU in several consecutive CPRI superframes are not all 0, the CPRI ring network link is switched to a normal state; if the downlink port of each RU times out or the downlink port is successfully linked but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a transition state.

[0018] Preferably, when the main optical port of the EU detects link abnormality status information reported by the RU, or the auxiliary optical port detects that the link is normal but the read RU topology ID is 0, the auxiliary optical port carries the topology ID allocated by the EU to the RU in the second configuration data sent down.

[0019] Preferably, the downlink data is downlink IQ data.

[0020] Preferably, both the first configuration data and the second configuration data are carried through a VS channel.

[0021] Preferably, starting from the RU directly connected to the main optical port of the EU, each RU is numbered 1, 2, 3...N in the forward direction of the CPRI ring network link, and the forward delay compensation information is calculated according to the following formula:

[0022]

[0023] Among them, T fw (n) represents the forward delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (1) represents the propagation delay from the main optical port of EU to RU No. 1, t 12 (k) represents the propagation delay from RU (k-1) to RU k.

[0024] Preferably, the reverse delay compensation information is calculated according to the following formula:

[0025]

[0026] Among them, T rw (n) represents the reverse delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, N represents the total number of RUs in the CPRI ring network link, t 12 (N) represents the propagation delay from the auxiliary optical port of EU to RU No. N, t 12 (N-1) represents the propagation delay from RU No. N to RU No. (N-1).

[0027] A CPRI ring network communication system disclosed in the present invention includes a CPRI ring network link having an EU and a plurality of RUs, wherein the CPRI ring network link is defined to have a normal state, a reverse state, and a transition state;

[0028] In the normal state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link to RUs of each level in sequence and then back to the auxiliary optical port of the EU;

[0029] In the reverse state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link and transmitted to the RU located on one side of the broken link. At the same time, data is also transmitted from the auxiliary optical port of the EU along the reverse direction of the CPRI ring network link and transmitted to the RU located on the other side of the broken link.

[0030] The transition state serves as an intermediate state between the normal state and the reverse state;

[0031] During the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and first configuration data to the RU directly connected thereto, and the auxiliary optical port sends downlink data and second configuration data to the RU directly connected thereto, wherein the first configuration data includes the topology ID assigned by the EU to the RU and the forward delay compensation information of each RU, and the second configuration data includes the reverse delay compensation information of each RU;

[0032] After receiving the downlink data, the first configuration data and the second configuration data, the RU saves the data and forwards them to other RUs step by step after modifying the topology ID;

[0033] The status of the uplink port and the downlink port of the RU is detected in real time, and the state switching of the CPRI ring network link is controlled according to the status of the uplink port and the downlink port. When the CPRI ring network link is switched to the normal state or the reverse state, delay compensation is performed on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information, and the reverse delay compensation information.

[0034] The advantages of the CPRI ring network communication fault self-healing method and system disclosed in the present invention are:

[0035] 1. During the operation of the CPRI ring network link disclosed in the present invention, the main optical port and auxiliary optical port of the EU can continuously send downlink data to the RU, and periodically transmit configuration data. There is no need to start the auxiliary optical port data transmission only when the link fails, and the data conversion speed is faster;

[0036] 2. When the CPRI ring network link of the present invention works normally, the EU simultaneously calculates the forward delay compensation and reverse delay compensation of each RU and sends them to each RU for storage. When the link switches state, each RU can select the corresponding delay compensation information according to the target state of the switch and its own topology ID to perform fast delay compensation, which has stronger applicability and faster response speed.

[0037] 3. The present invention sets various state switching conditions to form a state machine for fault detection and link self-healing. The state machine is used to determine and switch the link working state of CPRI, which can effectively prevent misjudgment caused by unstable optical path recovery clock, avoid chain switching back and forth, and improve the stability of link operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flowchart of the steps of a CPRI ring network communication fault self-healing method described in this embodiment;

[0039] Figure 2 is a schematic diagram of the structure of a CPRI ring network link in a normal state according to this embodiment;

[0040] Figure 3 is a schematic diagram of the structure of the CPRI ring network link in the reverse state described in this embodiment;

[0041] Figure 4 is a schematic diagram of the state switching of the CPRI ring network link described in this embodiment;

[0042] Figure 5 It is a schematic diagram of the structure of one example of the CPRI ring network link in this embodiment. DETAILED DESCRIPTION

[0043] like Figure 1-Figure 5 As shown, a CPRI ring network communication fault self-healing method described in the present disclosure includes:

[0044] In a CPRI ring network link having an EU and several RUs, it is defined that the CPRI ring network link has a normal state (NORMAL state), a reverse state (REVERSE) and a transition state (IDLE state).

[0045] Specifically, if Figure 2 As shown in the figure, the agreed link installation and wiring method is that port 0 of the default RU is the downstream inlet and port 1 is the downstream outlet. N RUs are cascaded and numbered in sequence. The main optical port of the EU is connected to port 0 of RU No. 1, and then port 1 of RU No. 1 is connected to port 0 of RU No. 2, and so on, until the Nth RU at the end is connected to the auxiliary optical port of the EU to form a CPRI ring network link.

[0046] like Figure 2As shown, under normal conditions, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link to RUs of each level in sequence and then back to the auxiliary optical port of the EU;

[0047] like Figure 3 As shown, in the reverse state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link and transmitted to the RU located on one side of the broken link. At the same time, data is also transmitted from the auxiliary optical port of the EU along the reverse direction of the CPRI ring network link and transmitted to the RU located on the other side of the broken link.

[0048] The transition state serves as an intermediate state between the normal state and the reverse state;

[0049] During the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and the first configuration data to the RU directly connected to it, and the auxiliary optical port sends downlink data and the second configuration data to the RU directly connected to it. The first configuration data includes the topology ID assigned by the EU to the RU and the forward delay compensation information of each RU, and the second configuration data includes the reverse delay compensation information of each RU.

[0050] Specifically, when the link is normal, the first configuration data sent by the EU main optical port carries the topology ID assigned by the EU to the RU, and the auxiliary optical port does not send the topology ID. When the EU main optical port detects the abnormal link status information reported by the RU, such as the loss of synchronization of the superframe synchronization word reception, discontinuous superframe number, and LOS / LOF reported by the optical module, the auxiliary optical port is made to carry the topology ID assigned by the EU to the RU in the second configuration data sent, so as to ensure that the topology ID can be assigned to the RU in the event of a link abnormality. Or the auxiliary optical port detects that the link is normal, but the read RU topology ID is 0. In this case, there is a connection abnormality between the RUs when the link is initially connected, and the auxiliary optical port will also carry the topology ID assigned by the EU to the RU in the second configuration data sent.

[0051] After receiving the downlink data, the first configuration data and the second configuration data, the RU saves them and forwards them to other RUs step by step after modifying the topology ID. Specifically, the topology ID sent by the main optical port to RU No. 1 can be defined as 0-1. After receiving the downlink data and configuration data, RU No. 1 saves them and modifies the topology ID, for example, by adding 1 to the last part of the digits, and modifies the topology ID to 0-2, and then forwards them together with the downlink data to RU No. 2. RU No. 2 saves them after receiving them, and so on. For the topology ID sent down from the auxiliary optical port, in order to distinguish it from the main optical port, it can be defined as 1-1.

[0052] In a specific embodiment, the downlink data is downlink IQ data, and the first configuration data and the second configuration data are both carried through the VS channel.

[0053] Real-time detection of the status of the uplink port and the downlink port of the RU, and control of the CPRI ring network link to switch the state according to the status of the uplink port and the downlink port, specifically:

[0054] like Figure 4 As shown, after the CPRI ring network link is powered on, it enters the IDLE state by default, and then the FPGA at the bottom of the RU starts to work and performs fault detection of the CPRI link in real time. For each RU, port 0 is uniformly defined as the uplink port and port 1 is the downlink port.

[0055] When the CPRI ring network link is in the IDLE state, if condition ① is met: the uplink ports of each RU are successfully linked, and the topology IDs received by the RU in several consecutive CPRI superframes are not all 0, then the CPRI ring network link is switched to the NORMAL state;

[0056] If condition ④ is met: the downlink ports of each RU are successfully linked, and the uplink ports of each RU fail to establish a link, or the uplink ports are successfully linked but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, then the CPRI ring network link is switched to the REVERSE state;

[0057] When the CPRI ring network link is in the NORMAL state, if condition ② is met: the uplink port of each RU fails to establish a link or the uplink port successfully establishes a link but the topology ID received by the RU in several consecutive CPRI superframes is all 0, this situation is a lost topology, then the CPRI ring network link is switched to the REVERSE state;

[0058] When the CPRI ring network link is in the REVERSE state, if condition ③ is met: the uplink ports of each RU are successfully linked, and the RU detects that the received topology IDs are not all 0 within several consecutive CPRI superframes, the CPRI ring network link is switched to the NORMAL state;

[0059] If condition ⑤ is met: the downlink port of each RU does not establish a link for a long time, that is, the link establishment times out (the timeout can be judged by a preset time threshold), or the downlink port successfully establishes the link but the topology ID received by the RU in several consecutive CPRI superframes is all 0, then the CPRI ring network link is switched to the IDLE state.

[0060] Therefore, a state machine can be formed through various preset state switching conditions to control the state switching of the CPRI ring network link. In actual operation, the CPRI ring network link usually runs in the NORMAL state or the REVERSE state, and the IDLE state is only used as an intermediate transition state between the above two states. The CPRI link will not stay in this state for a long time, and usually after fault detection and link self-healing by the above state machine, the CPRI will eventually return to the NORMAL state, thereby realizing a complete forward loop topology.

[0061] When the CPRI ring network link is switched to the normal state or the reverse state, delay compensation is performed on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information and the reverse delay compensation information.

[0062] Specifically, the topology ID of the RU is numbered in the above manner. This step mainly completes the calculation of the optical fiber propagation delay of each RU in the link through the CPRI underlying synchronization mechanism. By using the symmetry of the optical path, the forward compensation delay and reverse compensation delay of any RU in the link can be calculated at the same time, and the forward and reverse delay compensation information are transmitted to each level of RU through the aforementioned VS channel for storage. The details are as follows:

[0063] Starting from the RU directly connected to the main optical port of the EU, each RU is numbered 1, 2, 3...N in the forward direction of the CPRI ring network link, and the forward delay compensation information is calculated according to the following formula:

[0064]

[0065] Among them, T fw (n) represents the forward delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (1) represents the propagation delay from the main optical port of EU to RU No. 1, t 12 (k) represents the propagation delay from RU (k-1) to RU k.

[0066] The reverse delay compensation information is calculated according to the following formula:

[0067]

[0068] Among them, T rw (n) represents the reverse delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, N represents the total number of RUs in the CPRI ring network link, t 12(N) represents the propagation delay from the auxiliary optical port of EU to RU No. N, t 12 (N-1) represents the propagation delay from RU No. N to RU No. (N-1).

[0069] The above formula can be used to calculate the forward delay compensation information and reverse delay compensation information of each RU according to the topology ID of the RU. Every time the state of the CPRI ring network link switches to the normal state or the reverse state, it can be determined whether the RU itself is located in the forward propagation path or the reverse propagation path in the link according to the switched target state, and then the position of the RU in the link is determined according to the topology ID of the RU, thereby determining the delay compensation information that each RU should select, and performing delay compensation on each RU according to the delay compensation information.

[0070] The following is an example to describe in detail the working process of the CPRI ring network communication fault self-healing method of this embodiment:

[0071] In this example, six RUs are cascaded under one EU. Along the forward propagation direction of the link, the six RUs are numbered as RU 1, RU 2, ... RU 6. Finally, port 1 of RU 6 is connected to the auxiliary optical port of the EU.

[0072] After the link enters the working state, it is in the IDLE state. The FPGA at the bottom of the RU starts working and performs real-time fault detection of the CPRI link, and controls the CPRI ring network link to switch states according to the preset judgment conditions. For example, if the aforementioned condition ① is met, the CPRI ring network link is switched to the NORMAL state.

[0073] like Figure 5 As shown in the figure, when the optical path between RU 2 and RU 3 fails, the uplink port of RU 3 will not be able to correctly receive the underlying CPRI synchronization information sent by RU2, for example, the superframe synchronization word reception will be out of sync, causing RU 3 to meet the above condition ②, and the link will enter the REVERSE state.

[0074] The main optical port and auxiliary optical port of EU send the same downlink data at the same time, and also send the first configuration data and the second configuration data respectively, that is, the main port of EU sends the topology ID 0-1 and downlink IQ data to RU No. 1; after RU 1 receives it, it adds one to the topology ID to obtain the configuration topology 0-2 of the next-level RU and forwards the IQ data to RU 2. At this time, because the loop detects that the link from RU2 to RU3 has been disconnected, the auxiliary optical port of EU will send the topology ID 1-1 to RU No. 6; after RU No. 6 receives it, it adds one to the topology ID to obtain the configuration topology 1-2 of the next-level RU and forwards the IQ data to RU 5. Finally, the downlink data can be transmitted simultaneously through both sides, and the VS channel configures the topology ID to all RUs. RU 1 to RU 6 obtain unique topology IDs corresponding to: 0-1, 0-2, 1-4, 1-3, 1-2, 1-1.

[0075] The topology ID of RU 2 at the breakpoint is 0-2, and its forward delay compensation information is calculated as follows:

[0076] T fw (2) = T max -t 12 (1)-t 12 (2)

[0077] Among them, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (1) represents the propagation delay from the main optical port of EU to RU No. 1, t 12 (2) represents the propagation delay from RU 1 to RU 2.

[0078] The reverse delay compensation information of RU 2 at the breakpoint is calculated as:

[0079] T rw (2) = T max -t 12 (3)-t 12 (4)-t 12 (5)-t 12 (6)

[0080] Among them, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (6) represents the propagation delay from the auxiliary optical port of EU to RU No. 6, t 12 (5) represents the propagation delay from RU No. 6 to RU No. 5, and so on.

[0081] The topology ID of RU 3 at the breakpoint is 1-4, and its forward delay compensation information is calculated as follows:

[0082] Tfw (3) = T max -t 12 (1)-t 12 (2)-t 12 (3)

[0083] Among them, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (1) represents the propagation delay from the main optical port of EU to RU No. 1, t 12 (2) represents the propagation delay from RU 1 to RU 2.

[0084] The reverse delay compensation information of RU 3 at the breakpoint is calculated as:

[0085] T rw (3) = T max -t 12 (4)-t 12 (5)-t 12 (6)

[0086] Among them, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (6) represents the propagation delay from the auxiliary optical port of EU to RU No. 6, t 12 (5) represents the propagation delay from RU No. 6 to RU No. 5, and so on.

[0087] After the breakpoint detection, it is known that RU 1 and RU 2 are located on the forward transmission path, and the compensation delay adopts the forward delay compensation information T fw (1) and T fw (2); RU 3, RU 4, RU 5 and RU 6 are located on the reverse transmission path, and the compensation delay uses the reverse delay compensation information T rw (3) T rw (4) T rw (5) T rw (6) After the above delay compensation, the consistency of the total downlink delay of each RU can be ensured.

[0088] In the description of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0089] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present disclosure.

Claims

1. A CPRI ring network communication fault self-healing method, characterized in that: include: In a CPRI ring network link having an EU and a plurality of RUs, the CPRI ring network link is defined to have a normal state, a reverse state and a transition state; In the normal state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link to RUs of each level in sequence and then back to the auxiliary optical port of the EU; In the reverse state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link and transmitted to the RU located on one side of the broken link. At the same time, data is also transmitted from the auxiliary optical port of the EU along the reverse direction of the CPRI ring network link and transmitted to the RU located on the other side of the broken link. The transition state serves as an intermediate state between the normal state and the reverse state; During the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and first configuration data to the RU directly connected thereto, and the auxiliary optical port sends downlink data and second configuration data to the RU directly connected thereto, wherein the first configuration data includes the topology ID assigned by the EU to the RU and the forward delay compensation information of each RU, and the second configuration data includes the reverse delay compensation information of each RU; After receiving the downlink data, the first configuration data and the second configuration data, the RU saves the data and forwards them to other RUs step by step after modifying the topology ID; Detect the status of the uplink port and the downlink port of the RU in real time, and control the CPRI ring network link to switch the state according to the status of the uplink port and the downlink port. When the CPRI ring network link switches to the normal state or the reverse state, perform delay compensation on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information, and the reverse delay compensation information; When the main optical port of the EU detects link abnormality status information reported by the RU, or the auxiliary optical port detects that the link is normal but the read RU topology ID is 0, the auxiliary optical port carries the topology ID allocated by the EU to the RU in the second configuration data sent down.

2. The CPRI ring network communication fault self-healing method according to claim 1, characterized in that: According to the status of the uplink port and the downlink port, controlling the CPRI ring network link to switch the state is specifically as follows: When the CPRI ring network link is in a transition state, if the uplink port of each RU is successfully linked, and the topology IDs received by the RU in several consecutive CPRI superframes are not all 0, the CPRI ring network link is switched to a normal state; if the downlink port of each RU is successfully linked, and the uplink port of each RU fails to establish a link or the uplink port is successfully linked but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a reverse state; When the CPRI ring network link is in a normal state, if the uplink port of each RU fails to establish a link or the uplink port successfully establishes a link but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a reverse state; When the CPRI ring network link is in a reversal state, if the uplink port of each RU is successfully linked, and the topology IDs received by the RU in several consecutive CPRI superframes are not all 0, the CPRI ring network link is switched to a normal state; if the downlink port of each RU times out or the downlink port is successfully linked but the topology IDs received by the RU in several consecutive CPRI superframes are all 0, the CPRI ring network link is switched to a transition state.

3. The CPRI ring network communication fault self-healing method according to any one of claims 1-2, characterized in that: The downlink data is downlink IQ data.

4. The CPRI ring network communication fault self-healing method according to any one of claims 1-2, characterized in that: The first configuration data and the second configuration data are both carried through the VS channel.

5. The CPRI ring network communication fault self-healing method according to claim 1, characterized in that: Starting from the RU directly connected to the main optical port of the EU, each RU is numbered 1, 2, 3...N in the forward direction of the CPRI ring network link, and the forward delay compensation information is calculated according to the following formula: Among them, T fw (n) represents the forward delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, t 12 (1) represents the propagation delay from the main optical port of EU to RU No. 1, t 12 (k) represents the propagation delay from RU (k-1) to RU k.

6. The CPRI ring network communication fault self-healing method according to claim 5, characterized in that: The reverse delay compensation information is calculated according to the following formula: Among them, T rw (n) represents the reverse delay compensation value of the nth RU in the CPRI ring network link, T max It represents the maximum delay value of the link set by EU according to the longest fiber pulling distance, N represents the total number of RUs in the CPRI ring network link, t 12 (N) represents the propagation delay from the auxiliary optical port of EU to RU No. N, t 12 (N-1) represents the propagation delay from RU No. N to RU No. (N-1).

7. A CPRI ring network communication system, characterized in that: A CPRI ring network link including a EU and a plurality of RUs is included, and the CPRI ring network link is defined to have a normal state, a reverse state, and a transition state; In the normal state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link to RUs of each level in sequence and then back to the auxiliary optical port of the EU; In the reverse state, data is transmitted from the main optical port of the EU along the forward direction of the CPRI ring network link and transmitted to the RU located on one side of the broken link. At the same time, data is also transmitted from the auxiliary optical port of the EU along the reverse direction of the CPRI ring network link and transmitted to the RU located on the other side of the broken link. The transition state serves as an intermediate state between the normal state and the reverse state; During the operation of the CPRI ring network link, the main optical port of the EU sends downlink data and first configuration data to the RU directly connected thereto, and the auxiliary optical port sends downlink data and second configuration data to the RU directly connected thereto, wherein the first configuration data includes the topology ID assigned by the EU to the RU and the forward delay compensation information of each RU, and the second configuration data includes the reverse delay compensation information of each RU; After receiving the downlink data, the first configuration data and the second configuration data, the RU saves the data and forwards them to other RUs step by step after modifying the topology ID; Detect the status of the uplink port and the downlink port of the RU in real time, and control the state switching of the CPRI ring network link according to the status of the uplink port and the downlink port, and when the CPRI ring network link is switched to the normal state or the reverse state, perform delay compensation on each RU according to the switched target state, the topology ID of the RU, the forward delay compensation information, and the reverse delay compensation information; When the main optical port of the EU detects link abnormality status information reported by the RU, or the auxiliary optical port detects that the link is normal but the read RU topology ID is 0, the auxiliary optical port carries the topology ID allocated by the EU to the RU in the second configuration data sent down.

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