TWI831589B - Mobile fronthaul, method for routing dispersion and computer-readable storage medium - Google Patents

Abstract

A Mobile Fronthaul (MFH), a corresponding method for routing dispersion and a corresponding computer-readable storage medium are provided, which use the characteristics of an optical fiber ring to transmit traffic flows of base stations back to the machine room in a clockwise or counterclockwise direction. The present invention divides the fiber optical cables connected to the base stations into groups. The transmission directions of the cables of each group on the same optical fiber ring are dispersed into clockwise transmission or counterclockwise transmission, so as to reduce the possibility of simultaneous disconnection of adjacent base stations when a barrier occurs on the optical fiber ring. Hence, users would only feel short-term signal instability instead of a complete disconnection. Therefore, user experience and system efficiency would be improved.

Description

Mobile fronthaul network and its line dispersion method and computer-readable storage media

The present invention relates to a mobile fronthaul (MFH) network and its line or circuit dispersion method. It utilizes the characteristics of a ring optical cable to transmit traffic in the forward or reverse direction, and reduces the line or circuit interruption of large-area adjacent base stations by grouping and diverging into directions. probability of news.

When ring-type optical cables were first used in mobile networks, they used a single core wire and only used one direction to transmit traffic. In addition, optical cables in different directions were reserved for backup routes when obstacles occurred. With the rapid development of mobile networks, the demand for traffic transmission bandwidth has increased, but the expansion of optical cable resources has been limited by the limitation of full pipes and has become insufficient.

In response to the increasing demand, different optical cables that were originally redundant routes were also used. Although this solves the problem of insufficient optical cables, it may cause the problem of not being able to find a backup route when an optical cable failure occurs. Long-term and large-scale signal interruptions will cause inconvenience to users, increase customer complaints, and affect the revenue and reputation of telecommunications companies.

In addition, when telecommunications operators that provide base station services set up base stations, the coverage areas of neighboring base stations will partially overlap. This is so that when a certain base station loses service, neighboring base stations can Continue to provide services so that users will not experience long-term signal interruptions. However, in addition to the design of overlapping traffic of base stations, the traffic of base stations relies on transmission layer optical cables. If the optical cables connected to adjacent base stations are disconnected at the same time, user communications will be interrupted. In order to avoid the above situation, most existing technologies use adjusting the power parameters of adjacent base stations to reduce the range of signal interruption caused by obstructing base stations. However, there are still problems with poor user experience and system efficiency.

In order to solve the above problems, the present invention provides a line or circuit dispersion method, which is applied to a mobile fronthaul network. The mobile fronthaul network includes a ring optical cable and a plurality of base stations. The ring optical cable is provided with a plurality of optical cable supply points, and the The line or circuit dispersion method includes: according to the number of dispersed objects at each optical cable supply point, the dispersed objects are divided into at least a common point group and a staggered group, wherein each of the dispersed objects is directly connected to the ring The optical cable of the ring-type optical cable and one of the base stations, or the optical cable that indirectly connects the ring-type optical cable and one of the base stations through a wavelength demultiplexer; and the optical cables in each of the common point groups are respectively dispersed. The dispersion objects are relative to the traffic transmission direction of the ring optical fiber cable and the dispersion objects in the interleaving group are relative to the traffic transmission direction of the ring optical fiber cable.

The present invention also provides a computer-readable storage medium that stores instructions that are read by a computing device, a mobile device, a computer or a server to execute the above line or circuit dispersion method.

The present invention also provides a mobile fronthaul network, including a ring optical cable and a plurality of base stations, wherein: the ring optical cable is provided with a plurality of optical cable supply points; each optical cable supply point has at least one dispersed target; each dispersed target It is an optical cable that directly connects the ring-type optical cable and one of the base stations, or it is an optical cable that indirectly connects the ring-type optical cable with one of the base stations through a wavelength demultiplexer; the dispersed objects are based on The distribution quantity of each optical cable supply point is divided into a plurality of groups; and, in each such group , the numbers of forward and reverse dispersion targets relative to the traffic transmission direction of the ring optical cable are equal or only differ by one.

In one embodiment, the ring optical cable is connected to each of the plurality of base stations through optical cables.

The present invention utilizes the characteristics of ring optical cables to enable adjacent base stations to use optical cables in different directions to transmit signals, thereby reducing the risk of large-area base stations being unable to transmit signals due to a single obstacle event in the ring optical cable. No matter where the obstacle point of the optical cable is, the line or circuit dispersion method of the present invention can control the probability of simultaneous disconnection of adjacent base stations within a certain range, thereby reducing the probability of large-scale disconnection and improving user experience and System efficiency.

100: Computer room

201~209: Optical cable supply point

301~307,309: Wavelength demultiplexer

401~406: Direct supply optical cable

500: Ring optical cable

501,502: Base station

511~513,521~523: Interruption rate curve

601~604: Common points group

701~710: breakpoint

802~807,902~905,1002~1005: steps

1 to 4 are line or circuit architecture diagrams of a mobile fronthaul network according to embodiments of the present invention.

Figure 5 shows the interruption rate of scattered targets in the common point group.

Figure 6 shows the outage rate of scattered targets in the staggered group.

Figure 7 is a schematic diagram of base station disconnection before and after implementing the line or circuit dispersion method of the present invention.

8 to 10 are flowcharts of a line or circuit dispersion method according to an embodiment of the present invention.

The terms used in the present invention are explained below with reference to FIG. 1 , which is a line or circuit architecture diagram of a mobile fronthaul network according to an embodiment of the present invention.

Ring optical cable 500: The starting point of the ring optical cable is the computer room end, and then returns to the computer room after detouring, so the end point is also the computer room end. Taking Figure 1 as an example, the ring optical cable 500 starts from the computer room 100, goes around once and then returns to the computer room 100.

Optical cable supply point: The optical cable supply point is the manual hole through which the optical cable passes, which is convenient for pulling out smaller optical cables from the ring optical cable to connect to the Wavelength Division Multiplexer (WDM) or directly connect to the base station, such as Figure 1 The optical cable supply points 201~209.

Neighboring base stations: All base stations connected to the same ring optical cable are called neighboring base stations. For example, all base stations (shown as signal towers) in Figure 1 are called adjacent base stations. Some of them are directly connected to the ring optical cable without WDM. For example, base station 501 is directly connected to the ring optical cable without WDM. 500. In addition, some base stations are indirectly connected to the ring optical cable through WDM. For example, the base station 502 is indirectly connected to the ring optical cable 500 through WDM 303.

WDM: The 5G mobile network adopts the "Centralized Radio Access Network" (C-RAN) architecture. The transmission of base station signals uses WDM to centralize more than one base station traffic line or circuit, and then Backhaul to the computer room through optical cables, such as WDM 301~306 in Figure 1.

Optical cable direct supply: The optical cable is directly pulled out from the optical cable supply point to connect to the base station without going through WDM. This kind of optical cable that is directly connected to the base station can be called a direct supply optical cable, such as the direct supply optical cables 401~406 in Figure 1.

Traffic transmission direction: The ring optical cable contains multiple small optical cables. Each small optical cable can be used as a dedicated line connecting the computer room to a WDM or a base station. At the small optical cable cutout, you can choose to use the left or right end of the cutout optical cable to connect to WDM or base station equipment. If you choose to use the clockwise side of the optical cable, it is called the forward traffic transmission direction. If you choose to use the counterclockwise side of the optical cable, it is called the forward traffic transmission direction. Optical cable is called the reverse traffic transmission direction. The above-mentioned traffic transmission direction can also be called the optical cable connection direction.

Breakpoint: The optical cable may break due to damage caused by road construction or accidents, which is called a breakpoint.

In order to reduce the probability of large-scale disconnection, the present invention needs to first divide the base stations into groups. According to the number of WDM or optical cable direct supply base stations connected to the same optical cable supply point, they are divided into two groups: common point and staggered. The flow chart of grouping is shown in Figure 8.

Common point: When there are multiple WDM or multiple direct optical cables on an optical cable supply point, it is called a common point or a common point group. A ring optical cable will have at least one common group. For example, WDM 301 and 302 in Figure 1 form a common point group 601, and direct optical cables 402 and 403 form a common point group 603.

Interleaving: When there is only one WDM or only one direct optical cable at an optical cable supply point, it is called an interleaving point. All interleaving points on a ring optical cable form an interleaving group, and a ring optical cable will only have one interleaving group. For example, the direct-supply optical cable 401, WDM 303 and direct-supply optical cable 406 in FIG. 1 form a staggered group on the ring-type optical fiber cable 500.

Dispersion target: adjacent base stations connected to the same ring optical cable are grouped as a unit, and their lines or circuits are dispersed in a forward and reverse staggered manner. Lines or circuits that are dispersed within the same group are called dispersed targets. Each dispersed target can be a direct-supply optical cable directly connecting the base station and the ring optical cable or an optical cable connecting the WDM and the ring optical cable.

The present invention uses a single ring-type optical cable as a dispersed basic unit, and different ring-type optical cables as independent basic units without affecting each other. Figure 1 is used as an example to illustrate the implementation steps of the invention.

1 is a line or circuit architecture diagram of a mobile fronthaul network before implementing the line or circuit dispersion method of the present invention according to an embodiment of the present invention, in which the direction of use of the line or circuit optical cable is indicated by an arrow (↓ or ↑ or ← or → )express. For example, WDM 301 is forward, direct supply optical cable 401 is reverse, WDM 304 is forward, and WDM 306 is reverse.

The present invention utilizes the characteristic of the ring optical cable that can transmit traffic in the forward or reverse direction to disperse the risk of simultaneous disconnection of adjacent base stations. Dispersion can be divided into two parts. One is the decentralized reconnection of existing base station lines or circuits, and the other is the decision on the direction of the optical cable to be used before the base station lines or circuits are built. The following explains each step of the line or circuit dispersion method shown in Figure 8:

First, in step 802, establish the relationship between the front and back positions of the optical cable supply points on the ring optical cable, that is, obtain the front and back order of the optical cable supply points on the ring optical cable, and record the relationship between each optical cable supply point and the front and rear optical cable supply points. distance. The order and distance of the above-mentioned optical cable supply points can be taken from the computer or server in the computer room.

Next, in step 803, base station lines or circuits are divided into common point groups and staggered groups.

Common point group: If there is at least one WDM or at least one optical cable direct supply base station on a single optical cable supply point, it is determined in step 804 that this optical cable supply point belongs to the common point group.

Interleaving group: If there is only one WDM or one optical cable direct supply base station on a single optical cable supply point, it is determined in step 805 that this optical cable supply point belongs to the interleaving group.

Then, perform the following common-point group dispersion for each common-point group:

Dispersion of common-point groups with an even number of dispersed targets: In step 806, determine whether more than 50% of all dispersed targets of the common-point group are forward or reverse; if not, that is, whether forward or reverse If the diversified targets each account for exactly 50%, then there is no need for diversification, and the process ends; if there is, that is, the forward or reverse diversified targets exceed 50%, the process proceeds to step 807 for diversification.

Specifically, if there are many forward dispersed targets in the common group, some of them will be changed to reverse direction, so that 50% of the dispersed targets transmit traffic in the forward direction and the other 50% transmit traffic in the reverse direction. ; On the contrary, if there are many reverse divergent targets in the common group, some of them will be changed to the forward direction, so that 50% of the divergent targets transmit traffic in the forward direction and the other 50% transmit traffic in the reverse direction.

Taking the common point group 601 in Figure 1 as an example, WDM 301 and WDM 302 are both forward before dispersion. When the breakpoint 701 occurs, both WDM 301 and WDM 302 in the common point group 601 will be disconnected. If the WDM 302 is changed to the reverse direction according to the line or circuit dispersion method of the present invention, as shown in Figure 2, then when the breakpoint 701 occurs or any breakpoint occurs, the common point group 601 will only have 50% of the bases The station is disconnected. Since the original forward and reverse dispersion targets of the common point group 603 are 50% each, according to the analysis of the present invention, The scattered method does not require modification. The common point group 604 needs to change one of the scattered targets to the forward direction. Each common-point group is shown in Figure 2 after being reconnected.

Dispersion of common-point groups with an odd number of scatter targets: In step 806, first reduce the scatter targets in the common-point group by 1, i.e., temporarily exclude one of the scatter targets with more same directions, and then Determine whether more than 50% of the remaining dispersed targets in the common-point group are forward or reverse; if not, there is no need to disperse, and the process ends; if so, the process proceeds to step 807 for diversification.

Specifically, part of the more dispersed targets in the forward direction and the reverse direction in the common point group is changed to the opposite direction, so that the number of forward and reverse dispersed targets is exactly 1. In other words, in addition to the above mentioned Except for the temporary exclusion of the dispersed targets, the remaining 50% of the dispersed targets transmit traffic in the forward direction and the other 50% transmit the traffic in the reverse direction.

Taking the common point group 602 in Figure 1 as an example, WDM 304, WDM 305 and WDM 306 have common points, and their directions are forward, forward and reverse respectively. According to the above-mentioned dispersion method, the common-point groups 602 do not need to be dispersed.

In addition, perform the following staggered group dispersion for the staggered group:

Dispersion in a staggered group with an even number of dispersed targets: In step 806, determine whether more than 50% of all dispersed targets in the staggered group are forward or reverse; if not, the process ends; if so, then The process enters step 807 for dispersion, so that 50% of the dispersion targets transmit traffic in the forward direction and the other 50% transmit traffic in the reverse direction, and the forward and reverse dispersion targets must be based on the forward or reverse direction on the ring optical cable. The positions are arranged in staggered order.

For example, if a certain diversification target in the staggered group is reverse, then the next diversification target in the forward direction in the staggered group must be forward, and the next diversification target in the forward direction in the staggered group must be reverse. For another example, if a certain dispersed target in the staggered group is in the forward direction, then the staggered group The next scatter in the group that is inverse must be in the opposite direction, and the next scatter in that staggered group that is in the opposite direction must be in the forward direction, and so on.

Dispersion in a staggered group with an odd number of scattered targets: In step 806, first reduce the scattered targets in the staggered group by 1, i.e., temporarily exclude one of the dispersed targets with more in the same direction, and then determine the Among the remaining diversified targets in the staggered group, whether more than 50% of the diversified targets are forward or reverse; if not, there is no need to diversify, and the process ends; if so, the process proceeds to step 807 for diversification.

Specifically, part of the more dispersed targets in the forward and reverse directions in the staggered group is changed to the opposite direction, so that the number of forward and reverse dispersed targets is exactly 1, and the number of forward and reverse dispersed targets is exactly 1. Dispersed objects must be staggered according to their forward or reverse position on the ring optical cable.

Taking the staggered group in Figure 1 as an example, the staggered group includes a direct supply optical cable 401, a WDM 303 and a direct supply optical cable 406, the directions of which are all reverse. According to the above-mentioned dispersion method, the number of forward and reverse dispersion targets needs to differ by 1, and they need to be interleaved in the ring optical cable in order, so the WDM 303 in the center is changed to the forward direction, as shown in Figure 2.

Add the dispersion of dispersion targets to the common point group: the process is shown in Figure 9.

First, in step 902, it is determined that this operation is to add or delete a dispersed target. This operation is to add a dispersed target, so the process proceeds to step 903.

In step 903, a new distributed target is added, for example, a WDM or direct optical cable is added to a certain common point group. Next, in step 905, the direction of the newly added scattering target is set to the direction with the smaller number of the original scattering targets of the common-point group. If the number of forward and reverse diversification targets among the original diversification targets of the common-point group is equal, the newly added diversification targets can be set to forward or reverse direction at will.

For example, a new WDM 307 is added to the common group 602 in Figure 3. The original reverse dispersion targets in the common group 602 are less than the forward dispersion targets, so the newly added WDM 307 is set to reverse, as shown in Figure 3 shown.

Dispersion of new scattered targets in the staggered group: In the already dispersed staggered group, new staggered targets may be added. The process is shown in Figure 10.

First, in step 1002, it is determined that this operation is to add or delete a dispersed target. This operation is to add a dispersed target, so the process proceeds to step 1003.

In step 1003, a new dispersed target is added, for example, a WDM or direct-supply optical cable is added to the staggered group. Next, in step 1005, without changing the direction of the original dispersed target, the optical cable connection direction of the newly added dispersed target is set to one of the other dispersed targets in the staggered group that is closest to the newly added dispersed target. The opposite direction of the fiber optic cable connection direction.

Taking Figure 3 as an example, a staggered WDM 309 is added at the optical cable supply point 206. The newly added WDM 309 is located between the WDM 303 and the direct supply optical cable 406 in the staggered group. According to the above dispersion method, the intersection point closest to the optical cable supply point 206 is the WDM 303 of the optical cable supply point 203, and the direction of WDM 303 is reverse. Therefore, when WDM 309 is built, its optical cable connection direction should be forward.

Delete the scatter of scattered targets in a common group: the process is shown in Figure 9.

First, in step 902, it is determined that this operation is to add or delete a dispersed target, and this operation is to delete a dispersed target, so the process proceeds to step 904.

In step 904, the designated scattered targets in the designated common point group are deleted, and other dispersed targets do not need to be replaced.

Delete the scatter of scattered targets in the staggered group: the process is shown in Figure 10.

First, in step 1002, it is determined that this operation is to add or delete a dispersed target, and this operation is to delete a dispersed target, so the process proceeds to step 1004.

In step 1004, the designated diversified targets in the staggered group are deleted without changing to other dispersed diversified targets.

During diversification, conventional methods can be used to change the divergence target to the opposite direction and actually set the direction of the newly added divergence target. However, the part that determines the direction of the dispersion target during dispersion or addition is automatically executed by computing devices such as mobile devices, computers, or servers to determine or set the direction of optical cable connection that should be changed. Through this, construction workers and maintenance personnel The scattered objects can be reconnected directly according to the direction determined or set by the computing device without having to judge the direction by oneself.

In one embodiment, the present invention further provides a computer-readable storage medium, such as a memory, a floppy disk, a hard disk or an optical disk. The computer-readable storage medium can store instructions, and the instructions can be read by a computing device, a mobile device, a computer or a server to execute the circuit or circuit dispersion method described above.

In the absence of a systematic method to disperse the lines or circuit directions of each base station, when a breakpoint occurs in the optical cable, continuous and large-scale base station outages may occur. The location of the breakpoint is different, and the scale of the outage is also different. According to the base station lines or circuits reconnected according to the line or circuit dispersion method of the present invention, no matter where the break point occurs, the scale of the base station outage can be controlled within a certain small range.

For example, as shown in Figure 7, the left picture is a schematic diagram of a base station outage before the line or circuit dispersion method of the present invention is implemented. A single obstacle event may cause most base stations in the same area to be out of service, while the right picture is a diagram after the implementation of the present invention. Schematic diagram of base station outage after the line or circuit dispersion method. A single obstacle event can only cause small-scale outage, which can avoid continuous large-area outage.

Table 1 below shows the ratio of scattered targets that will cause a break when a common point group occurs at a break point. Figure 5 is a graph of the interruption rate drawn according to Table 1. Curves 511 to 513 respectively correspond to the lowest interruption rate, the highest interruption rate and the average interruption rate in Table 1. As can be seen from Table 1 and Figure 5, the average interruption rate is 50%. No matter where the breakpoint occurs, the average interruption rate of the dispersed targets of the common-point group is 50%, because the common-point groups are dispersed, and the optical cable connection direction is about half forward and reverse.

Taking Figure 4 as an example, the possible locations of breakpoints are 701~710 respectively. No matter where the breakpoint occurs on the ring optical cable 500, approximately half of the base stations in the common group 601~604 will interrupt the signal.

Table 2 below shows the proportion of scattered targets in the staggered group that will be interrupted when a breakpoint occurs. Figure 6 is an interruption rate curve drawn according to Table 2. Among them, curves 521 to 523 correspond to the lowest interruption rate, the highest interruption rate and the average interruption rate in Table 2 respectively. The average interruption rate curve 523 is actually Horizontal line, the highest interruption rate curve 522 is located above the average interruption rate curve 523, and the lowest interruption rate curve 521 is located below the average interruption rate curve 523. It can be seen from Table 2 and Figure 6 that the average interruption rate of the lowest and highest interruption rates is close to 50%. When the number of interleaved and scattered targets is larger, the difference between the lowest and the highest interruption rate is smaller, and the greater the interruption rate is. Approaching 50%.

After adjustment by the line or circuit dispersion method of the present invention, no matter where the breakpoint occurs, the average interruption rate of each common point group is 50%, and the lowest and highest interruption rates of the staggered group can be controlled as shown in the figure within the range shown in 6. In addition, the greater the number of dispersed targets in the staggered group, the smaller the difference between the lowest and highest outage rates, and the closer the average outage rate is to 50%.

The above embodiments are only illustrative to illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone with ordinary knowledge in this technical field can modify and change the above embodiments without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be as listed in the patent application scope described below.

100: Computer room

201~209: Optical cable supply point

301~306: Wavelength demultiplexer

401~406: Direct supply optical cable

500: Ring optical cable

601~604: Common points group

701: Breakpoint

Claims (11)

A line dispersion method is applied to a mobile fronthaul network. The mobile fronthaul network includes a ring optical cable and a plurality of base stations. The ring optical cable is provided with a plurality of optical cable supply points. The line dispersion method includes: according to each optical cable supply point. The number of dispersed objects of line points divides the dispersed objects into at least one common point group and one staggered group, wherein each of the dispersed objects is an optical cable directly connecting the ring optical cable and one of the base stations, Or it is an optical cable that indirectly connects the ring optical cable to one of the base stations through a wavelength demultiplexer, and among them, for each optical cable supply point, if there are multiple scattered objects on the optical cable supply point, then Divide the dispersed objects on the optical cable supply point into common point groups corresponding to the optical cable supply point in the at least one common point group. If there is only a single dispersed object on the optical cable supply point, then divide the single dispersed object into The dispersed objects are divided into the interleaved groups; and the dispersed objects in each of the common groups are dispersed relative to the traffic transmission direction of the ring optical cable and the dispersed objects in the interleaved group are relative to the ring optical cable. service delivery direction. The line dispersion method as described in claim 1, wherein the step of distributing the traffic transmission directions of the dispersed targets includes: for each of the common points groups, if the number of dispersed targets in the common points group is an even number, Then set the traffic transmission direction of the distributed targets in the common group so that the number of distributed targets in the common group with the forward and reverse traffic transmission directions is equal. The line dispersion method as described in claim 1, wherein the step of dispersing the traffic transmission directions of the dispersion targets includes: For each common group, if the number of scattered targets in the common group is an odd number, set the traffic transmission direction of the scattered targets in the common group so that the message in the common group There is only one difference in the number of scattered targets between forward and reverse service transmission directions. The line dispersion method as described in claim 1, further comprising: adding a new dispersion target in the designated co-point group in the at least one common point group, and setting the traffic transmission direction of the newly added dispersion target as It is the same as the smaller number of the original forward and backward diversification targets of the specified common point group. The line dispersion method as described in claim 1, further comprising: deleting the dispersed objects in the designated common point group in the at least one common point group without changing the information of other dispersed objects in the designated common point group. service delivery direction. The line dispersion method as described in claim 1, wherein the step of dispersing the traffic transmission directions of the dispersion targets includes: if the number of dispersion targets in the stagger group is an even number, then setting the dispersion in the stagger group The traffic transmission direction of the target is such that the number of scattered targets in the interleaved group with the traffic transmission direction being forward and reverse is equal, and the traffic transmission direction of the scattered targets in the interleaved group is along the forward direction. Arranged in a staggered direction or in the opposite direction. The line dispersion method as described in claim 1, wherein the step of dispersing the traffic transmission directions of the dispersion targets includes: if the number of dispersion targets in the stagger group is an odd number, then setting the dispersion in the stagger group The traffic transmission direction of the target is such that the number of scattered targets in the interleaved group with the traffic transmission direction being forward and reverse is only one different, and the traffic transmission direction of the scattered targets in the interleaved group is along the The forward direction or the reverse direction is arranged in a staggered manner. The line dispersion method as described in claim 1 further includes: adding a new dispersion target in the staggered group, and setting the traffic transmission direction of the newly added dispersion target to a distance from the new dispersion target in the staggered group. Increase the divergence target by adding the opposite of another diversification target closest to it. The line dispersion method as described in claim 1 further includes: deleting the dispersion targets in the staggered group without changing the traffic transmission direction of other dispersion targets in the staggered group. A computer-readable storage medium stores instructions that are read by a computing device, a mobile device, a computer or a server to execute the line dispersion method described in any one of claims 1 to 9. A mobile fronthaul network includes a ring optical cable and a plurality of base stations, wherein: the ring optical cable is provided with a plurality of optical cable supply points; each optical cable supply point has at least one distributed target; each distributed target is directly connected to the The optical cable between the ring optical cable and one of the base stations, or the optical cable indirectly connecting the ring optical cable and one of the base stations through a wavelength demultiplexer; the dispersion objects are based on the optical cables The number of distribution points of the optical cable supply points is divided into at least one common point group and one staggered group; for each optical cable supply point, if there are multiple scattered objects on the optical cable supply point, then the scattered objects on the optical cable supply point The objects are divided into common point groups corresponding to the optical cable supply point in the at least one common point group. If there is only a single scattered object at the optical cable supply point, the single scattered object is classified into the staggered group; and The dispersed objects in each of the common groupings and the staggered groups are respectively dispersed relative to the traffic transmission direction of the ring optical cable, so that in each of the groups, relative to the ring The number of dispersed objects in the forward and reverse directions of the optical cable's traffic transmission is equal or only differs by one.

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