Patent Application
20230336244
The present disclosure relates to a multiplex transmission system and a resource control method for the multiplex transmission system.
A multiplex transmission system for multiplexing and transmitting a plurality of signals between two points is disclosed in NPL 1. Specifically, NPL 1 discloses multiplexing a plurality of signals using wavelength division multiplexing (WDM). At each of the two points to be transmitted, a multiplex transmission apparatus for performing wavelength demultiplexing is installed.
In addition, a redundancy technique of an access network is described in NPL 2. In order to cope with various failures such as a disconnection of an optical fiber cable connecting a multiplex transmission apparatus or a breakdown of a transmission/reception unit (TRx) in the multiplex transmission apparatus, a redundancy technique as described in NPL 2 is required.
In a conventional redundancy technique such as that described in NPL 2, it is necessary to prepare resources of a standby system in advance from a stage of introduction of a multiplex transmission system in preparation for a failure. The resources of the standby system required in the conventional redundancy technique end up being wasted during normal time where no failure occurs.
The present disclosure has been devised to solve the foregoing problem. An object of the present disclosure is to provide a multiplex transmission system and a multiplex transmission system resource control method capable of realizing a redundant configuration for coping with a failure while reducing useless resources.
A multiplex transmission system according to the present disclosure is a multiplex transmission system which multiplexes and transmits a plurality of signals between a first multiplex transmission apparatus and a second multiplex transmission apparatus, the multiplex transmission system including: a resource pool which is provided in the first multiplex transmission apparatus and which has a resource capable of selectively constructing one or more functions among a plurality of functions; a monitoring unit which monitors, when a failure occurs, information on the failure; and a control unit which controls the resource pool. The control unit causes, when a failure occurs, the resource pool to execute construction of a function necessary for constructing a redundant configuration according to contents of the failure on the basis of a monitoring result by the monitoring unit.
A resource control method for a multiplex transmission system according to the present disclosure is a method for controlling, in a multiplex transmission system which multiplexes and transmits a plurality of signals between a first multiplex transmission apparatus and a second multiplex transmission apparatus, a resource pool which is provided in the first multiplex transmission apparatus and which has a resource capable of selectively constructing one or more functions among a plurality of functions. The resource control method includes the steps of: monitoring, when a failure occurs, information on the failure; and controlling the resource pool so as to construct a function for constructing a redundant configuration according to contents of the failure on the basis of a result of the step of monitoring.
With the multiplex transmission system and the resource control method of the multiplex transmission system according to the present disclosure, a redundant configuration for coping with a failure can be realized while reducing useless resources.
A mode for carrying out a multiplex transmission system and a resource control method for the multiplex transmission system according to the present disclosure will be described with reference to the accompanying drawings. In each drawing, same reference signs are assigned to identical or corresponding parts and repetition of descriptions will be simplified or omitted as deemed appropriate. It should be noted that the present disclosure is not limited to the following embodiment and any constituent element disclosed in the embodiment can be modified or omitted without departing from the spirit and the scope of the present disclosure.
The first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200 are communicably connected by an optical fiber cable. According to the multiplex transmission system, by multiplexing a plurality of signals to be transmitted between two points, the number of optical fiber cables required for transmitting the plurality of signals between the two points can be reduced. For example, the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200 can be communicably connected to each other by one optical fiber cable.
One or more slave stations are communicably connected to one of the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200. One or more master stations are communicably connected to the other of the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200. In the illustrated configuration example, a first slave station 11 and a second slave station 12 are connected to the first multiplex transmission apparatus 100 and a first master station 21 and a second master station 22 are connected to the second multiplex transmission apparatus 200.
In the present embodiment, it is assumed that the multiplex transmission system is applied to a mobile front hole. In this case, the first master station 21 and the second master station 22 correspond to CUs (Central Units) and/or DUs (Distributed Units) of a base station. In addition, in this case, the first slave station 11 and the second slave station 12 correspond to RUs (Radio Units). The first slave station 11 and the first master station 21 are base stations of a first mobile carrier. The second slave station 12 and the second master station 22 are base stations of a second mobile carrier. The first mobile carrier and the second mobile carrier are different mobile carriers (mobile communication providers). An antenna is connected to each slave station. Each antenna outputs a radio wave to an individual area to form a reception area. Each master station may be formed as an individual apparatus for each mobile carrier or formed as an integrated apparatus. Similarly, each slave station may be formed as an individual apparatus for each mobile carrier or formed as an integrated apparatus.
The first client port of the first multiplex transmission apparatus 100 is provided with a first client-side O/E unit 121 and a first client-side E/O unit 122. The second client port of the first multiplex transmission apparatus 100 is provided with a second client-side O/E unit 123 and a second client-side E/O unit 124. The first multiplex transmission apparatus 100 further includes a first line-side E/O unit 111, a first line-side O/E unit 112, a second line-side E/O unit 113 and a second line-side O/E unit 114, and a first multiplexing unit 101.
An optical signal input to the first client port of the first multiplex transmission apparatus 100 is converted into an electric signal by the first client-side O/E unit 121 and output to the first line-side E/O unit 111. The first line-side E/O unit 111 converts the input electric signal into an optical signal and outputs the optical signal to the first multiplexing unit 101. In addition, an optical signal input to the second client port of the first multiplex transmission apparatus 100 is converted into an electric signal by the second client-side O/E unit 123 and output to the second line-side E/O unit 113. The second line-side E/O unit 113 converts the input electric signal into an optical signal and outputs the optical signal to the first multiplexing unit 101.
The first multiplexing unit 101 multiplexes the optical signals input from the first line-side E/O unit 111 and the second line-side E/O unit 113. The optical signal multiplexed by the first multiplexing unit 101 is transmitted from the first multiplex transmission apparatus 100 to the second multiplex transmission apparatus 200.
In addition, a multiplexed optical signal transmitted from the second multiplex transmission apparatus 200 to the first multiplex transmission apparatus 100 is input to the first multiplexing unit 101. The first multiplexing unit 101 separates the multiplexed signal input from the second multiplex transmission apparatus 200 and outputs the separated signal to the first line-side O/E unit 112 and the second line-side O/E unit 114, respectively.
The first line-side O/E unit 112 converts the optical signal input from the first multiplexing unit 101 into an electric signal and outputs the electric signal to the first client-side E/O unit 122. The first client-side E/O unit 122 converts the input electric signal into an optical signal and outputs the optical signal to the first client port of the first multiplex transmission apparatus 100. The second line-side O/E unit 114 converts the optical signal input from the first multiplexing unit 101 into an electric signal and outputs the electric signal to the second client-side E/O unit 124. The second client-side E/O unit 124 converts the input electric signal into an optical signal and outputs the optical signal to the second client port of the first multiplex transmission apparatus 100.
In this way, the first line-side E/O unit 111, the first line-side O/E unit 112, the first client-side O/E unit 121 and the first client-side E/O unit 122 correspond to the first client port of the first multiplex transmission apparatus 100. In addition, the second line-side E/O unit 113, the second line-side O/E unit 114, the second client-side O/E unit 123 and the second client-side E/O unit 124 correspond to the second client port of the first multiplex transmission apparatus 100.
The second multiplex transmission apparatus 200 is configured in the same manner as the first multiplex transmission apparatus 100. Illustration of an internal configuration of the second multiplex transmission apparatus 200 will be omitted. As described above, the second multiplex transmission apparatus 200 is provided with the third client port and the fourth client port. The second multiplex transmission apparatus 200 includes a client-side O/E unit and a client-side E/O unit that correspond to each client port. The second multiplex transmission apparatus 200 includes a line-side O/E unit and a line-side E/O unit that correspond to each client port. In addition, the second multiplex transmission apparatus 200 includes a second multiplexing unit which functions similarly to the first multiplexing unit 101.
The line-side O/E units and the line-side E/O units included in each multiplex transmission apparatus are made of optical modules that emit light at a fixed wavelength. The line-side O/E units and the line-side E/O units included in the first multiplex transmission apparatus 100 can communicate only with an optical module which emits light at the same wavelength as themselves among the line-side O/E units and the line-side E/O units included in the second multiplex transmission apparatus 200.
Each slave station and the first multiplex transmission apparatus 100 may be connected to each other via a coupler (not illustrated) in order to construct a redundant configuration of a transmission line. Similarly, each master station and the second multiplex transmission apparatus 200 may be connected to each other via a coupler for constructing a redundant configuration of a transmission line. In place of the coupler, a switch capable of switching between transmission lines provided inside each multiplex transmission apparatus may be used to construct a redundant configuration of the transmission line between the base station and each multiplex transmission apparatus.
In the illustrated configuration example, the first multiplex transmission apparatus 100 includes a first line switching unit 102 for constructing a redundant configuration of a transmission line between multiplex transmission apparatuses. Although not illustrated, the second multiplex transmission apparatus 200 includes a second line switching unit that functions similarly to the first line switching unit 102. The line switching units are for constructing a redundant configuration of a transmission line between the multiplex transmission apparatuses. The line switching units are connected to each other by a plurality of paths (optical fiber cables). In the illustrated configuration example, the line switching units are connected to each other by two paths. A signal from the multiplexing units is input to the line switching units. The line switching units select an arbitrary path among the plurality of paths connecting the line switching units, and output a signal from the multiplexing unit to the selected line. The line switching units may be provided outside the multiplex transmission apparatuses. As described above, in the present embodiment, the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200 are connected to each other by a plurality of switchable transmission paths.
In addition, as shown in
In the present disclosure, a redundant configuration is constructed using the resource pool 130. Accordingly, resources can be utilized more effectively than before. According to the present disclosure, it is possible to achieve a redundant configuration for coping with a failure while reducing useless resources.
The resource pool 130 may also be provided in the second multiplex transmission apparatus 200. In the present disclosure, the resource pool 130 need only be provided in at least one of the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200.
Functional units that can be constructed in resources of the resource pool 130 include, for example, an SW unit 131, an error correction processing unit 132, a modulating unit 133, and a filtering unit 134. The SW unit 131 has a switching function. For example, the SW unit 131 constructs a redundant path when a failure occurs in a transmission/reception unit such as each O/E unit and each E/O unit in the first multiplex transmission apparatus 100.
The error correction processing unit 132 has a function of correcting a bit error rate due to signal deterioration occurring on a transmission path. The error correction processing unit 132 detects and corrects an error on a reception-side on the basis of an error correction code added to data on a transmission-side. An arbitrary code such as a Reed-Solomon code or an LDPC code is allocated to the error correction code. The error correction processing unit 132 is constructed in a resource of the resource pool 130 when, for example, a path of a switching destination becomes long in the case of a line breakdown.
The modulating unit 133 has a function of converting a signal from a client port into a multi-valued signal. The modulating unit 133 generates, for example, a PAM4 signal. The modulating unit 133 can increase a bit rate while maintaining a baud rate. The modulating unit 133 can reduce the cost of an O/E unit and an E/O unit, for example.
The filtering unit 134 is used to lower a transmission rate and has a function of filtering and discarding a part of a main signal.
In addition, the multiplex transmission system according to the present embodiment includes a management control unit 140. The management control unit 140 includes, for example, a resource pool-side monitoring unit 141, a line-side monitoring unit 142, and a resource calculating unit 143. Although the management control unit 140 is provided outside the first multiplex transmission apparatus 100 in the illustrated configuration example, at least a part of the functions of the management control unit 140 may be provided inside the first multiplex transmission apparatus 100. In addition, at least a part of the functions of the management control unit 140 may be provided inside the second multiplex transmission apparatus 200.
The resource pool-side monitoring unit 141 monitors a current state of the resource pool 130. Monitoring information by the resource pool-side monitoring unit 141 is sent to the resource calculating unit 143. The line-side monitoring unit 142 monitors states of the first line-side E/O unit 111, the first line-side O/E unit 112, the second line-side E/O unit 113, and the second line-side O/E unit 114. The monitoring information by the line-side monitoring unit 142 is sent to the resource calculating unit 143. For example, when any one of the first line-side E/O unit 111, the first line-side O/E unit 112, the second line-side E/O unit 113, and the second line-side O/E unit 114 breaks down, the line-side monitoring unit 142 notifies the resource calculating unit 143 of the breakdown. The resource calculating unit 143 performs calculation processing for constructing each functional unit in a resource in the resource pool 130. The resource calculating unit 143 performs calculation processing on the basis of the monitoring information transmitted from the resource pool-side monitoring unit 141 and the line-side monitoring unit 142. In addition, the resource calculating unit 143 instructs the resource pool 130 to construct a necessary functional unit on the basis of the calculation processing result.
The management control unit 140 may be constituted of a computer including a processor and a memory as hardware. The processor is also referred to as a CPU (Central Processing Unit), a central processing device, processing equipment, an arithmetic unit, a microprocessor, a microcomputer, or a DSP. As the memory, for example, non-volatile or volatile semiconductor memories such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM, a magnetic disk, an optical disk, a flexible disk, an optical disk, a compact disc, a mini disk, a DVD, and the like are applicable.
A program as software is stored in the memory of the management control unit 140. The management control unit 140 performs preset processing by causing a processor to execute a program stored in the memory and implements each function as a result of cooperation between hardware and software.
The line-side monitoring unit 142 according to the present embodiment functions as a monitoring unit that monitors, when a failure occurs, information on the failure. In addition, the resource calculating unit 143 according to the present embodiment functions as a control unit that causes the resource pool 130 to execute construction of a function necessary for constructing a redundant configuration according to contents of the failure on the basis of a monitoring result by the monitoring unit.
Next, a flow of operations of the multiplex transmission system configured as described above will be described.
In subsequent step S12, the resource pool is caused to execute construction of a function for constructing a redundant configuration according to contents of the failure on the basis of the result of the monitoring step. The processing in step S12 is also referred to as a function construction step in the present disclosure. The monitoring step and the function construction step are executed by the management control unit 140 and the resource pool 130.
According to the resource control method as shown in
For example, when a failure occurs in a transmission/reception unit in the first multiplex transmission apparatus 100, the line-side monitoring unit 142 notifies the resource calculating unit 143 of information on the failure. When a failure occurs in the transmission/reception unit in the first multiplex transmission device 100, the resource calculating unit 143 causes the resource pool 130 to execute function construction for constructing a new transmission path that avoids a transmission path including a location of the failure.
For example, when a transmission path of the standby system is longer than that of the active system prior to switching, a bit error rate due to signal deterioration between the first multiplex transmission apparatus 100 and the second multiplex transmission apparatus 200 increases. Therefore, the resource calculating unit 143 causes the resource pool 130 to execute the construction of the error correction processing unit 132. Thus, even when the transmission line after switching becomes long at the time of an occurrence of a failure, signal transmission can be performed without error.
The operations of the multiplex transmission system according to the present disclosure are not limited to the examples shown in
In addition, the multiplex transmission apparatus constituting the multiplex transmission system according to the present disclosure and the resource control method of the multiplex transmission system can also be realized through cooperation between hardware and software by having a processor execute a program stored in a memory to perform preset processing. Furthermore, a program for realizing the apparatus and the method according to the present disclosure can be recorded on an information recording medium. Alternatively, a program for realizing the apparatus and the method according to the present disclosure can also be provided via a communication network.
The present disclosure can be used for a multiplex transmission system in which a plurality of signals are multiplexed and transmitted between a first multiplex transmission apparatus and a second multiplex transmission apparatus and for resource control of the multiplex transmission system.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/038017 | 10/7/2020 | WO |
