Optical communication system and monitoring method thereof

Abstract

The present invention discloses an optical communication system, which is an optical communication system composed of an optical ring network, comprising: a first optical communication device, which transmits a first optical signal of a first wavelength in a first direction, and transmits a second optical signal of a second wavelength in a second direction opposite to the first direction; and a second optical communication device, which, when receiving the first optical signal, reflects the first optical signal to generate a first reflected signal, and when receiving the second optical signal, reflects the second optical signal to generate a second reflected signal, and transmits the first reflected signal and the second reflected signal to the first optical communication device, and the first optical communication device analyzes the connection status of the second optical communication device based on the first reflected signal and the second reflected signal.

Description

Technical Field

[0001] The invention relates to an optical communication system and a monitoring method thereof. Background Art

[0002] With the emergence of various multimedia services based on the Internet and the network, large-capacity data traffic is increasing, and due to the emergence of smart phones, the demand for data services is increasing rapidly. As a result, the need to increase transmission capacity has also been proposed in optical communication networks such as wireless access networks suitable for mobile communications.

[0003] As a result, as the number of devices constituting an optical communication network increases and the complexity of the network structure increases significantly, effective management of the network, maintenance of the devices, etc. have begun to become important factors. In particular, a solution is needed that can prevent failures from occurring by discovering errors in optical communication network devices, and can quickly respond to failures when they occur, thereby improving service quality.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Korean Patent Publication No. 10-2008-0097795 Summary of the invention

[0007] Problems to be solved by the invention

[0008] An object of the present disclosure is to provide an optical communication system and a monitoring method thereof that can effectively monitor the connection status between optical communication devices constituting the optical communication system.

[0009] The technical problems to be achieved by the technical idea of ​​the present disclosure are not limited to the above problems, and those skilled in the art will clearly understand other problems not mentioned from the following description.

[0010] Solutions for solving problems

[0011] According to one aspect of the present invention, an optical communication device is disclosed, which is an optical communication device of an optical ring network, comprising: a first optical signal processing unit, which outputs a first optical signal of a first wavelength; a first multiplexer / demultiplexer, which outputs the first optical signal in a first direction, and receives and outputs a first reflected signal, wherein the first reflected signal is a signal after the first optical signal is reflected; a second optical signal processing unit, which outputs a second optical signal of a second wavelength; a second multiplexer / demultiplexer, which outputs the second optical signal in a second direction opposite to the first direction, and receives and outputs a second reflected signal, wherein the second reflected signal is a signal after the second optical signal is reflected; and a controller, which analyzes the connection status of a first remote optical communication device to which the first optical signal and the second optical signal are allocated based on the first reflected signal and the second reflected signal.

[0012] According to an exemplary embodiment, the first long-distance optical communication device may be configured to reflect the first optical signal to generate the first reflected signal, reflect the second optical signal to generate the second reflected signal, and transmit the generated first reflected signal and the second reflected signal to the optical communication device. Furthermore, the first long-distance optical communication device may be configured to generate the corresponding reflected signal only when the first optical signal or the second optical signal is received in a preset direction of the first direction and the second direction.

[0013] According to an exemplary embodiment, the controller may determine that an error occurs in the connection of the first remote optical communication device as long as any one of the first reflection signal and the second reflection signal is received.

[0014] According to an exemplary embodiment, the optical communication device may further include: a third optical signal processing unit, which outputs a third optical signal of a third wavelength to the first multiplexer / demultiplexer; and a fourth optical signal processing unit, which outputs a fourth optical signal of a fourth wavelength to the second multiplexer / demultiplexer. The first multiplexer / demultiplexer may multiplex the first optical signal and the third optical signal and output them to the first direction, and receive a third reflected signal and output it to the controller, wherein the third reflected signal is a signal after the third optical signal is reflected, the second multiplexer / demultiplexer may multiplex the second optical signal and the fourth optical signal and output them to the second direction, and receive a fourth reflected signal and output it to the controller, wherein the fourth reflected signal is a signal after the fourth optical signal is reflected, and the controller may analyze the connection status of the second remote optical communication device to which the third optical signal and the fourth optical signal are assigned based on the third reflected signal and the fourth reflected signal.

[0015] According to an exemplary embodiment, the second long-distance optical communication device may be configured to reflect the third optical signal to generate the third reflected signal, reflect the fourth optical signal to generate the fourth reflected signal, and transmit the third reflected signal and the fourth reflected signal to the optical communication device, and the second long-distance optical communication device may be configured to generate a corresponding reflected signal only when the third optical signal or the fourth optical signal is received in a preset direction of the first direction and the second direction.

[0016] According to an exemplary embodiment, the controller may determine that an error occurs in the connection of the second remote optical communication device as long as any one of the third reflection signal and the fourth reflection signal is received.

[0017] According to another aspect of the present invention, an optical communication system is disclosed, which is an optical communication system composed of an optical ring network, comprising: a first optical communication device, transmitting a first optical signal of a first wavelength in a first direction, and transmitting a second optical signal of a second wavelength in a second direction opposite to the first direction; and a second optical communication device, when receiving the first optical signal, reflecting the first optical signal to generate a first reflected signal, when receiving the second optical signal, reflecting the second optical signal to generate a second reflected signal, and transmitting the first reflected signal and the second reflected signal to the first optical communication device, wherein the first optical communication device analyzes the connection status of the second optical communication device based on the first reflected signal and the second reflected signal.

[0018] According to an exemplary embodiment, the second optical communication device may be configured to generate a corresponding reflection signal only when the first optical signal or the second optical signal is received in a preset direction of the first direction and the second direction.

[0019] According to an exemplary embodiment, the first optical communication device may determine that an error occurs in the connection with the second optical communication device as long as any one of the first reflection signal and the second reflection signal is received.

[0020] According to an exemplary embodiment, the first optical communication device may transmit a third optical signal of a third wavelength toward the first direction, and transmit a fourth optical signal of a fourth wavelength toward the second direction.

[0021] The above-mentioned optical communication system may also include: a third optical communication device, which reflects the above-mentioned third optical signal to generate a third reflected signal when receiving the above-mentioned third optical signal, and reflects the above-mentioned fourth optical signal to generate a fourth reflected signal when receiving the above-mentioned fourth optical signal, and transmits the above-mentioned third reflected signal and the above-mentioned fourth reflected signal to the above-mentioned first optical communication device. The above-mentioned first optical communication device can analyze the connection status of the above-mentioned third optical communication device based on the above-mentioned third reflected signal and the above-mentioned fourth reflected signal.

[0022] According to an exemplary embodiment, the third optical communication device may be configured to generate a corresponding reflection signal only when the third optical signal or the fourth optical signal is received in a preset direction of the first direction and the second direction.

[0023] According to an exemplary embodiment, as long as any one of the third reflection signal and the fourth reflection signal is received, the first optical communication device may determine that an error occurs in the connection of the third optical communication device.

[0024] Effects of the Invention

[0025] According to the present disclosure, there is an effect of effectively monitoring the connection status between optical communication devices.

[0026] Effects that can be obtained according to the embodiments of the technical idea of ​​the present disclosure are not limited to the above-mentioned effects, and those skilled in the art can clearly understand other effects that are not mentioned through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] A brief description of the drawings is provided to provide a more complete understanding of the drawings referenced in the detailed description of the present disclosure.

[0028] Figure 1 4 is a structural diagram of an optical communication system according to an embodiment of the present disclosure.

[0029] Figure 2 is a block diagram of a COT according to an embodiment of the present disclosure.

[0030] Figure 3 A block diagram of an RN according to an embodiment of the present disclosure.

[0031] Figures 4 to 13 1 is a diagram showing a first connection state (Example 1) to a tenth connection state (Example 10) of the optical communication system.

[0032] Fig.14 A diagram showing a monitoring table according to an embodiment of the present disclosure.

[0033] Description of Reference Numerals

[0034] 100: Optical communication systems

[0035] 110: Central Office Terminal (COT)

[0036] 120: Remote Node (RN). DETAILED DESCRIPTION

[0037] The technical concept of the present disclosure can be modified in various ways and various embodiments can be provided. Specific embodiments are shown in the drawings and described in detail. However, this is not intended to limit the technical concept of the present disclosure to specific embodiments, and should be understood to include all deformations, equivalent forms and alternative forms included in the scope of the technical concept of the present disclosure.

[0038] When describing the technical idea of ​​the present disclosure, if it is judged that the specific description of the relevant known technology may unnecessarily obscure the key points of the technical idea of ​​the present disclosure, its detailed description will be omitted. In addition, the numbers (e.g., first, second, etc.) used in the description of the present application are merely identification symbols used to distinguish one structural element from other structural elements.

[0039] In addition, in the present application, when it is mentioned that a structural element is "connected" or "contacted" to another structural element, the above-mentioned structural element can be directly connected to or directly contacted with another structural element. Unless there is a specific record to the contrary, it should be understood that other structural elements can be connected or contacted in the middle as a medium.

[0040] In addition, the terms "part", "device" and "processor" described in this document refer to a unit that processes at least one function or operation, and the unit can be implemented by hardware, software, or a combination of hardware and software such as a processor, a microprocessor, a microcontroller, a CPU (central processing unit), a GPU (graphics processing unit), an APU (accelerated processor unit), a DSP (digital signal processor), an ASIC (application specific integrated circuit), or an FPGA (field programmable gate array).

[0041] In addition, it is intended to clarify that the division of the structural parts in this application is only divided according to the main functions that each structural part is responsible for. That is, two or more structural parts described below can be combined into one structural part, or one structural part can be divided into two or more according to each subdivided function. In addition, each structural part described below can perform part or all of the functions that other structural parts are responsible for in addition to the main functions that it is responsible for, and some of the main functions that each structural part is responsible for can be shared and executed by other structural parts.

[0042] Hereinafter, various embodiments according to the technical idea of ​​the present disclosure are described in detail in sequence.

[0043] Figure 1 4 is a structural diagram of an optical communication system according to an embodiment of the present disclosure.

[0044] Reference Figure 1 According to an embodiment of the present disclosure, an optical communication system 100 may include a central office terminal (COT) 110 and n remote nodes (RN) 120-1 to 120-n (where n is a natural number). In the following, an application example of configuring an optical transport network is illustrated, where the optical transport network is a subnet of the fronthaul segment of a wireless access network architecture formed by the COT and n RNs 120-1 to 120-n. However, the technical idea of ​​the present disclosure is not limited to this. It is obvious that the technical idea of ​​the present disclosure can also be applied to optical transport networks such as midhaul and backhaul segments of a wireless access network architecture, as well as FTTx solutions and inbuilding solutions.

[0045] The COT 110 and the n RNs 120 - 1 to 120 - n may be configured as an optical ring network connected to each other in a ring topology structure.

[0046] Assuming that the optical communication system 100 according to an embodiment of the present disclosure is composed of a COT 110 and two RNs 120-1 and 120-2, the connection structure is described in more detail. The COT 110 and the two RNs 120-1 and 120-2 may respectively include input / output ports for connecting to each other. At this time, the first input / output port of the COT 110 may be connected to a first optical cable, and the second input / output port of the COT 110 may be connected to a second optical cable. In addition, the first input / output port of the first RN 120-1 may be connected to a first optical cable, and the second input / output port of the first RN 120-1 may be connected to a third optical cable. In addition, the first input / output port of the second RN 120-2 may be connected to a third optical cable, and the second input / output port of the second RN 120-2 may be connected to a second optical cable. Here, the first optical cable to the third optical cable may be a concept including not only a single optical cable but also a plurality of optical cables and their connection structures.

[0047] On the other hand, in the COT and two RNs connected to each other, the COT is a part that can be connected to the fronthaul section of the radio access network architecture to perform digital processing of the base station, for example, at least one digital unit (Digital Unit, DU) (or baseband unit (BaseBand Unit, BBU)). Each RN can be connected to a part that performs wireless processing of the above-mentioned base station, for example, at least one radio unit (Radio Unit, RU) (or remote radio head (RemoteRadio Head, RRH)). However, the present invention is not limited to this, and in the COT and two RNs connected to each other, the COT can be connected to at least one macro cell (Macro cell) RU, and each RN can be connected to at least one small cell (smallcell) RU. According to various fronthaul topologies of the radio access network architecture, various deformations can be made to the connection objects and interconnection structures of the COT and RN.

[0048] COT 110 may be a device that multiplexes base station signals and sends them to one or more connected RNs (one or more of 120-1 to 120-n). For example, COT 110 may receive a signal from a DU (not shown) and convert it into a WDM signal, and transmit the WDM signal to one or more RNs (one or more of 120-1 to 120-n) connected via an optical cable. That is, COT 110 may receive a plurality of base station signals and convert them into optical signals of different wavelengths from each other, and transmit the optical signals to one or more RNs 120-1 to 120-n. The base station signals may be baseband signals that comply with standards of fronthaul links such as Common Public Radio Interface (CPRI), Open Base Station Architecture Initiative (OBSAI), and Open Radio Equipment Interface (ORI).

[0049] Figure 1 In the example, COT 110 can transmit WDM signals in one direction of the ring network, i.e., transmit WDM signals to the first RN 120-1 through the first optical cable, and can transmit WDM signals in another direction of the ring network, i.e., transmit WDM signals to the nth RN 120-n through the second optical cable.

[0050] Each RN 120-1 to 120-n is a device located at a cell site side at a remote location. Each RN 120-1 to RN120-n is connected to COT 110, and can transmit a WDM signal received from COT 110 to at least one connected RU (not shown). That is, each RN 120-1 to 120-n can be a passive WDM device. On the other hand, each RN can be replaced by a remote terminal (RT). Various remote devices can be used according to the optical transmission network field to which the optical communication system 100 is applied.

[0051] According to an embodiment of the present disclosure, the COT 110 may use a monitoring optical signal to analyze the connection status between the COT 110 and the first RN 120-1, and between the COT 110 and the second RN 120-2, wherein the monitoring optical signal has a wavelength (i.e., a channel) that is distinguished from an optical signal corresponding to a base station signal. For example, the COT 110 transmits the monitoring optical signal to the first RN 120-1 and / or the second RN 120-2, and analyzes the connection status between the COT 110 and the first RN 120-1, and between the COT 110 and the second RN 120-2 by analyzing the monitoring optical signal reflected from the first RN 120-1 and / or the second RN 120-2.

[0052] Hereinafter, an analysis operation of the connection status of the COT 110 and the first RN 120 - 1 and the second RN 120 - 2 performed by the COT 110 will be described in more detail.

[0053] Figure 2 is a block diagram of a COT according to an embodiment of the present disclosure, Figure 3 is a block diagram of an RN according to an embodiment of the present disclosure. It should be noted that, for the sake of convenience, Figure 2 and Figure 3 Mainly shown are the main structures used for monitoring in the structures of COT and RN.

[0054] The COT 110 according to an embodiment of the present disclosure may include first to fourth optical signal processing units 210 to 240 , a controller (MCU) 250 , and first and second multiplexers / demultiplexers (MUX / DEMUX) 260 and 270 . Figure 2 The embodiment in which the COT 110 includes four optical signal processing sections and two multiplexers / demultiplexers is shown, however, various modifications may be made to the number of optical signal processing sections and multiplexers / demultiplexers, etc. For example, the number of optical signal processing sections may be increased according to the number of RNs.

[0055] The first to fourth optical signal processing units 210 to 240 may respectively generate optical signals for monitoring according to the control of the MCU 250 , and may output the generated optical signals to corresponding multiplexers / demultiplexers in the first and second multiplexers / demultiplexers 260 and 270 .

[0056] The first optical signal processing unit 210 may generate a first optical signal of a first wavelength λ1 and output it to the first multiplexer / demultiplexer 260. The second optical signal processing unit 220 may generate a second optical signal of a second wavelength λ2 and output it to the second multiplexer / demultiplexer 270. The third optical signal processing unit 230 may generate a third optical signal of a third wavelength λ3 and output it to the first multiplexer / demultiplexer 260. The fourth optical signal processing unit 240 may generate a fourth optical signal of a fourth wavelength λ4 and output it to the second multiplexer / demultiplexer 270.

[0057] The first to fourth wavelengths λ1 to λ4 may be wavelengths different from wavelengths used to transmit base station signals. For example, the first to fourth wavelengths λ1 to λ4 may be different from the wavelengths λRN1 of the base station signal transmitted to the first RN 120-1 and the wavelengths λRN2 of the base station signal transmitted to the second RN 120-2. That is, for ease of explanation, Figure 2 In the following, one wavelength of the base station signal allocated to the first RN 120-1 and one wavelength of the base station signal allocated to the second RN 120-2 are respectively shown, but there may be multiple wavelengths of the base station signal allocated to the first RN 120-1 and the second RN 120-2 respectively.

[0058] The first wavelength λ1, the second wavelength λ2, the third wavelength λ3, and the fourth wavelength λ4 may be wavelengths of bands divided in the same frequency band, respectively. For example, the first wavelength λ1 may be a wavelength of the L band of 1310 nm, the second wavelength λ2 may be a wavelength of the H band of 1310 nm. Also, the third wavelength λ3 may be a wavelength of the L band of 1370 nm, and the fourth wavelength λ4 may be a wavelength of the H band of 1370 nm.

[0059] In addition, the first wavelength λ1 and the second wavelength λ2 may be monitoring wavelengths assigned to the first RN 120-1, and the third wavelength λ3 and the fourth wavelength λ4 may be monitoring wavelengths assigned to the second RN 120-2. Such monitoring wavelengths may be wavelengths of supervisory channels or the like.

[0060] The first optical signal processing unit 210 to the fourth optical signal processing unit 240 may respectively include an optical transceiver (e.g., a 10Gb Small Form Factor Pluggable (XFP) optical transceiver, a Small Form-factor Pluggable (SFP) optical transceiver, a Quad Small Form-factor Pluggable (QSFP) optical transceiver, a C-Form-Factor Pluggable (CFP) optical transceiver, etc.), a signal combiner (e.g., a coupler), a filter, etc., so as to generate an optical signal of a wavelength set according to the control of the controller 250, and transmit it to the corresponding multiplexer / demultiplexer in the first multiplexer / demultiplexer 260 and the second multiplexer / demultiplexer 270. In this case, the optical transceiver may be a wavelength tunable optical transceiver, the transmitting port and the receiving port of the optical transceiver are connected to the signal combiner, the signal combiner is connected to the filter, and the filter may have a structure connected to a corresponding multiplexer / demultiplexer.

[0061] According to an embodiment, the first optical signal processing unit 210 to the fourth optical signal processing unit 240 may also be composed of a filter, wherein the filter is used to transmit an optical signal of a specified wavelength received from an external device to the corresponding multiplexer / demultiplexer in the first multiplexer / demultiplexer 260 and the second multiplexer / demultiplexer 270.

[0062] The first multiplexer / demultiplexer 260 can multiplex the service optical signals (first optical signal and third optical signal) corresponding to the base station signals of the first RN 120-1 and the second RN 120-2, and transmit the first WDM signal using the connected first optical cable. Hereinafter, the direction in which the optical signal is transmitted through the first multiplexer / demultiplexer 260 is referred to as "E" (EAST).

[0063] The second multiplexer / demultiplexer 270 may multiplex the service optical signals (the second optical signal and the fourth optical signal) corresponding to the base station signals of the first RN 120-1 and the second RN 120-2, and transmit the second WDM signal using the connected second optical cable. Hereinafter, the direction in which the optical signal is transmitted through the second multiplexer / demultiplexer 270 is referred to as "W" (WEST).

[0064] The first multiplexer / demultiplexer 260 may output a reflected signal received through the first optical cable to the controller 250 after transmitting the first WDM signal. In addition, the second multiplexer / demultiplexer 270 may output a reflected signal received through the second optical cable to the controller 250 after transmitting the second WDM signal.

[0065] As described above, the controller 250 can control the overall operation of the first optical signal processing unit 210 to the fourth optical signal processing unit 240 and / or the COT 110, and can analyze the reflected signal input from the first multiplexer / demultiplexer 260 and / or the second multiplexer / demultiplexer 270, thereby analyzing the connection status of one or more RNs 120-1 to 120-n constituting the optical communication system 100.

[0066] Reference Figure 3 , the first RN 120-1 may include: a first bandpass filter 310, a first wavelength filter 350-1, a first signal reflector 360-1, a second bandpass filter 320, a second wavelength filter 350-2, a second signal reflector 360-2 and a first RN multiplexer / demultiplexer 370-1. The second RN 120-2 may include: a third bandpass filter 330, a third wavelength filter 350-3, a third signal reflector 360-3, a fourth bandpass filter 340, a fourth wavelength filter 350-4, a fourth signal reflector 360-4 and a second RN multiplexer / demultiplexer 370-2.

[0067] Since the first bandpass filter 310 in the first RN 120-1 is connected to the second bandpass filter 320, the third bandpass filter 330 in the second RN 120-2 is connected to the fourth bandpass filter 340, and the second bandpass filter 320 is connected to the third bandpass filter 330, the COT 110, the first RN 120-1 and the second RN 120-2 can have a ring topology structure capable of bidirectionally sending / receiving optical signals.

[0068] Although not shown, in the first RN 120-1, the outputs of the first bandpass filter 310 and the second bandpass filter 320 may be connected to a signal combiner (e.g., a coupler), which may combine the outputs of the first bandpass filter 310 and the second bandpass filter 320 and transmit them to the first RN multiplexer / demultiplexer 370-1. Similarly, in the second RN 120-2, the outputs of the third bandpass filter 330 and the fourth bandpass filter 340 may be connected to a signal combiner, which may combine the outputs of the third bandpass filter 330 and the fourth bandpass filter 340-1 and transmit them to the second RN multiplexer / demultiplexer 370-2.

[0069] The first band pass filter 310 may include a band pass filter (BPF) capable of filtering a frequency band including the wavelength λRN1 of the base station signal allocated to the first RN 120 - 1 , the first wavelength λ1 , and the second wavelength λ2 .

[0070] When receiving the first WDM signal, the first bandpass filter 310 may filter the service optical signal and the first optical signal allocated to the first RN 120-1 from the first WDM signal and transmit them to the first wavelength filter 350-1 and the first RN multiplexer / demultiplexer 370-1.

[0071] Alternatively, when receiving the second WDM signal, the first bandpass filter 310 may filter the service optical signal and the second optical signal allocated to the first RN 120-1 from the second WDM signal and transmit them to the first wavelength filter 350-1 and the first RN multiplexer / demultiplexer 370-1.

[0072] The first wavelength filter 350-1 may include a wavelength selection filter capable of filtering the first wavelength λ1 and the second wavelength λ2 bands. The first wavelength filter 350-1 may filter the first optical signal or the second optical signal from the output of the first bandpass filter 310, and may output the filtered first optical signal or the second optical signal to the first signal reflector 360-1.

[0073] The first signal reflector 360-1 can reflect the optical signal output from the first wavelength filter 350-1 to output it in the opposite direction. For example, the first signal reflector 360-1 can output a signal after the first optical signal is reflected (hereinafter referred to as the first reflected signal) or a signal after the second optical signal is reflected (hereinafter referred to as the second reflected signal) to the first wavelength filter 350-1.

[0074] The first wavelength filter 350-1 may transmit the first reflected signal or the second reflected signal to the first bandpass filter 310. The first bandpass filter 310 may transmit the first reflected signal to the first multiplexer / demultiplexer 260 of the COT 110 through the connected optical cable, and may transmit the second reflected signal to the second multiplexer / demultiplexer 270 of the COT 110 through the second RN 120-2.

[0075] Similar to the first bandpass filter 310 , the second bandpass filter 320 may include a bandpass filter (BPF) capable of filtering a frequency band including the wavelength λRN1 of the base station signal allocated to the first RN 120 - 1 , the first wavelength λ1 , and the second wavelength λ2 .

[0076] When receiving the second WDM signal, the second bandpass filter 320 may filter the service optical signal and the second optical signal allocated to the first RN 120-1 from the second WDM signal and transmit them to the second wavelength filter 350-2 and the first RN multiplexer / demultiplexer 370-1.

[0077] Alternatively, when receiving the first WDM signal, the second bandpass filter 320 can filter the service optical signal and the first optical signal corresponding to the base station signal of the first RN 120-1 from the first WDM signal and transmit them to the second wavelength filter 350-2 and the first RN multiplexer / demultiplexer 370-1.

[0078] The second band pass filter 320 may transmit the unfiltered wavelength band to the first band pass filter 310 or the third band pass filter 330 of the second RN 120 - 2 .

[0079] The second wavelength filter 350-2 may include a wavelength selective filter capable of filtering the second wavelength λ2 band. The second wavelength filter 350-2 may filter the second optical signal from the output of the second bandpass filter 320 and transmit the filtered second optical signal to the second signal reflector 360-2.

[0080] The second signal reflector 360-2 may reflect the optical signal output from the second wavelength filter 350-2 to output it in the opposite direction. That is, the second signal reflector 360-2 may transmit the second reflected signal to the second wavelength filter 350-2.

[0081] The second wavelength filter 350-2 may transmit the second reflected signal to the second bandpass filter 320. The second bandpass filter 320 may transmit the second reflected signal to the second multiplexer / demultiplexer 270 of the COT 110 through the connected optical cable and the second RN 120-2.

[0082] As described above, unlike the first wavelength filter 350-1, the second wavelength filter 350-2 can only filter signals of a specific wavelength, i.e., the second optical signal. Therefore, when the second bandpass filter 320 is not connected to the second multiplexer / demultiplexer 270 side of the COT 110 through the optical cable and the second RN 120-2 to receive the second WDM signal, but is connected to the first multiplexer / demultiplexer 260 side of the COT 110 through the optical cable to receive the first WDM signal, the reflected signal will not be generated by the second wavelength filter 350-2 and the second signal reflector 360-2. Based on this characteristic, the COT 110 can detect changes in the connection state of the first RN 120-1.

[0083] On the other hand, the first RN multiplexer / demultiplexer 370-1 may multiplex the service optical signal output from the first bandpass filter 310 and / or the second bandpass filter 320 and transmit it to at least one connected RU (not shown). At this time, the first optical signal or the second optical signal may be filtered by the first RN multiplexer / demultiplexer 370-1 without being transmitted to the RU.

[0084] The second RN 120-2 has a structure corresponding to that of the first RN 120-1 described above, and can perform similar operations.

[0085] In particular, the second RN 120-2 may be configured such that the fourth wavelength filter 350-4 filters the third optical signal and the fourth optical signal corresponding to the third wavelength λ3 and the fourth wavelength λ4, and the third wavelength filter 350-3 only filters the third optical signal corresponding to the third wavelength λ3. When the connection state of the COT 110 and the second RN 120-2 is reversed, no reflection signal is generated in a specific direction.

[0086] In other words, when the third bandpass filter 330 is not connected to the first multiplexer / demultiplexer 260 side of the COT 110 through the optical cable and the first RN 120-1 to receive the first WDM signal, but is connected to the second multiplexer / demultiplexer 270 side of the COT 110 through the optical cable to receive the second WDM signal, no reflected signal is generated by the third wavelength filter 350-3 and the third signal reflector 360-2. Based on this characteristic, the COT 110 can detect the change in the connection state of the second RN 120-2.

[0087] The controller 250 may analyze the received reflection signals among the first to fourth reflection signals, thereby analyzing the connection status between the COT 110 and the first RN 120 - 1 and the connection status between the COT 110 and the second RN 120 - 2 .

[0088] For example, the controller 250 can analyze whether the first reflected signal and / or the second reflected signal corresponding to the first optical signal and / or the second optical signal transmitted from the COT 110 along different directions are received, and the time until reception, thereby determining whether the first RN 120-1 is normally connected (for example, the connection direction, etc.) and the distance to the first RN 120-1, etc.

[0089] In addition, the controller 250 can analyze whether the third reflected signal and / or the fourth reflected signal corresponding to the third optical signal and / or the fourth optical signal transmitted from the COT 110 along different directions are received, and the time until reception, thereby determining whether the second RN 120-2 is normally connected (for example, the connection direction, etc.) and the distance to the second RN 120-2, etc.

[0090] Will refer to Figures 4 to 14 , describing in detail the analysis action of the controller 250 on the connection status of the RN 120.

[0091] Figures 4 to 13 1 is a diagram showing a first connection state (CASE 1) to a tenth connection state (CASE 10) of an optical communication system, Fig.14 A diagram showing a connection status monitoring table according to an embodiment of the present disclosure.

[0092] First, refer to Figure 4 , shows a case where the "E" direction of the COT 110 is connected to the "W" direction of the first RN 120-1, and the "W" direction of the COT 110 is connected to the "E" direction of the second RN 120 (Example 1). At this time, the COT 110 and the first RN 120-1 can be connected via the first optical cable, the COT 110 and the second RN 120-2 can be connected via the second optical cable, and the first RN 120-1 and the second RN 120-2 can be connected via the third optical cable.

[0093] like Figure 3 As shown, since the first bandpass filter 310 of the first RN 120-1 is connected along the "W" direction of the first RN 120-1, the first WDM signal can be input to the first bandpass filter 310 side of the first RN 120-1. In this case, a first reflection signal can be generated by the first bandpass filter 310, the first wavelength filter 350-1 and the first signal reflector 360-1, and the generated first reflection signal can be output to the first bandpass filter 310 side, and can be transmitted to the COT 110 through the first optical cable.

[0094] like Figure 3 As shown, since the second bandpass filter 320 of the first RN 120-1 is connected along the "E" direction of the first RN 120-1, the second WDM signal can be input to the second bandpass filter 320 side of the first RN 120-1. In this case, a second reflected signal can be generated by the second bandpass filter 320, the second wavelength filter 350-2 and the second signal reflector 360-2, and the generated second reflected signal can be output to the second bandpass filter 320 side. The second reflected signal can be transmitted to the COT 110 through the third optical cable, the second RN 120-2 and the second optical cable.

[0095] like Figure 3As shown, since the third bandpass filter 330 of the second RN 120-2 is connected along the "W" direction of the second RN 120-2, the first WDM signal can be input to the third bandpass filter 330 side of the second RN 120-2. In this case, a third reflection signal can be generated by the third bandpass filter 330, the third wavelength filter 350-3 and the third signal reflector 360-3, and the generated third reflection signal can be output to the third bandpass filter 330 side. The third reflection signal can be transmitted to the COT 110 through the third optical cable, the first RN 120-1 and the first optical cable.

[0096] like Figure 3 As shown, since the fourth bandpass filter 340 of the second RN 120-2 is connected along the "E" direction of the second RN 120-2, the second WDM signal can be input to the fourth bandpass filter 340 side of the second RN 120-2. In this case, a fourth reflected signal can be generated by the fourth bandpass filter 340, the fourth wavelength filter 350-4 and the fourth signal reflector 360-4, and the generated fourth reflected signal can be output to the fourth bandpass filter 340 side, and can be transmitted to the COT 110 through the second optical cable.

[0097] The controller 250 may determine the connection status between the first RN 120 - 1 and the second RN 120 - 2 by comparing the received reflection signal with a preset connection status monitoring table.

[0098] exist Figure 4 In the example shown, the controller 250 may receive all of the first to fourth reflected signals, in which case the controller 250 may determine that both the first RN 120 - 1 and the second RN 120 - 2 are connected normally.

[0099] Reference Figure 5 , shows a case where the "E" direction of COT 110 is connected to the "W" direction of the second RN 120-2, and the "W" direction of COT 110 is connected to the "E" direction of the second RN 120-2 (Example 2). In this case, COT 110 and the second RN 120-2 can be connected via a first optical cable, COT 110 and the first RN 120-1 can be connected via a second optical cable, and the first RN 120-1 and the second RN 121-2 can be connected via a third optical cable.

[0100] like Figure 3As shown, since the first bandpass filter 310 of the first RN 120-1 is connected along the "W" direction of the first RN 120-1, the first WDM signal can be input to the first bandpass filter 310 of the first RN 120-1. In this case, a first reflection signal can be generated by the first bandpass filter 310, the first wavelength filter 350-1 and the first signal reflector 360-1, and the generated first reflection signal can be output through the third optical cable on the side of the first bandpass filter 310. The first reflection signal transmitted through the third optical cable can be transmitted to the COT 110 through the second RN 120-2 and the first optical cable.

[0101] like Figure 3 As shown, since the second bandpass filter 320 of the first RN 120-1 is connected along the "E" direction of the first RN 120-1, the second WDM signal can be input to the second bandpass filter 320 side of the first RN 120-1. In this case, a second reflected signal can be generated by the second bandpass filter 320, the second wavelength filter 350-2 and the second signal reflector 360-2, and the generated second reflected signal can be transmitted to COT110 through the second optical cable on the second bandpass filter 320 side.

[0102] like Figure 3 As shown, since the third bandpass filter 330 of the second RN 120-2 is connected along the "W" direction of the second RN 120-2, the first WDM signal can be input to the third bandpass filter 330 side of the second RN 120-2. In this case, a third reflected signal can be generated by the third bandpass filter 330, the third wavelength filter 350-3 and the third signal reflector 360-3, and the generated third reflected signal can be transmitted to COT110 through the first optical cable on the third bandpass filter 330 side.

[0103] like Figure 3 As shown, since the fourth bandpass filter 340 of the second RN 120-2 is connected along the "E" direction of the second RN 120-2, the second WDM signal can be input to the fourth bandpass filter 340 side of the second RN 120-2. In this case, a fourth reflected signal can be generated by the fourth bandpass filter 340, the fourth wavelength filter 350-4 and the fourth signal reflector 360-4, and the generated fourth reflected signal can be output through the third optical cable on the side of the fourth bandpass filter 340. The fourth reflected signal output through the third optical cable can be transmitted to the COT 110 through the first RN 120-1 and the second optical cable.

[0104] In this case, the controller 250 may also receive all of the first to fourth reflected signals, and may determine that the first RN 120 - 1 and the second RN 120 - 2 are connected normally.

[0105] refer to Figure 6 , shows a case where the "E" direction of COT 110 is connected to the "W" direction of the first RN 120-1 (Example 3). In this case, COT 110 and the first RN 120-1 can be connected through the first optical cable and the second optical cable, while COT 110 and the second RN 120-2 are not connected.

[0106] like Figure 3 As shown, since the first bandpass filter 310 of the first RN 120-1 is connected along the "W" direction of the first RN 120-1, when the first WDM signal is input to the first bandpass filter 310 side of the first RN 120-1, a first reflected signal can be generated and transmitted to the COT 110 through the first optical cable.

[0107] In addition, if Figure 3 As shown, since the second bandpass filter 320 of the first RN 120-1 is connected along the "E" direction of the first RN 120-1, when the second WDM signal is input to the second bandpass filter 320 side of the first RN 120-1, a second reflected signal can be generated and transmitted to the COT 110 through the second optical cable.

[0108] In this case, the controller 250 may receive the first and second reflected signals, but not the third and fourth reflected signals. Therefore, the controller 250 may determine that the first RN 120-1 is connected normally and the second RN 120-2 does not exist.

[0109] refer to Figure 7 , shows a case where the "E" direction of COT 110 is connected to the "W" direction of the second RN 120-2 (Example 4). In this case, COT 110 and the second RN 120-2 can be connected through the first optical cable and the second optical cable, while COT 110 and the first RN 120-1 are not connected.

[0110] like Figure 3 As shown, since the third bandpass filter 330 of the second RN 120-2 is connected along the "W" direction of the second RN 120-2, when the first WDM signal is input to the third bandpass filter 330 side of the second RN 120-2, a third reflected signal can be generated and transmitted to the COT 110 through the first optical cable.

[0111] In addition, since the fourth bandpass filter 340 of the second RN 120-2 is connected along the "E" direction of the second RN 120-2, when the second WDM signal is input to the fourth bandpass filter 340 side of the second RN 120-2, a fourth reflected signal can be generated and transmitted to the COT 110 through the second optical cable.

[0112] In this case, the controller 250 may receive the third and fourth reflected signals, but not the first and second reflected signals. Therefore, the controller 250 may determine that the second RN 120-2 is connected normally and the first RN 120-1 does not exist.

[0113] Reference Figure 8 , shows a case where the "E" direction of COT 110 is connected to the "E" direction of the first RN 120-1, and the "W" direction of COT 110 is connected to the "E" direction of the second RN 120-2 (Example 5). In this case, COT 110 and the first RN 120-1 can be connected via a first optical cable, COT 110 and the second RN 120-2 can be connected via a second optical cable, and the first RN 120-1 and the second RN 120-2 can be connected via a third optical cable.

[0114] Since the second bandpass filter 320 of the first RN 120-1 is connected along the "E" direction of the first RN 120-1, no reflection signal is generated when the first WDM signal is input to the second bandpass filter 320 side of the first RN 120-1. For the second wavelength filter 350-2 at the rear end of the second bandpass filter 320, it can only filter the second optical signal, so the first optical signal or the third optical signal of the first WDM signal cannot be filtered, and thus no reflection signal is generated.

[0115] On the other hand, since the first bandpass filter 310 of the first RN 120-1 is connected along the "W" direction of the first RN 120-1, when the second WDM signal is input to the first bandpass filter 310 side of the first RN 120-1, a second reflected signal can be generated by the first wavelength filter 350-1 and the first signal reflector 360-1 at the rear end of the first bandpass filter 310. This is because the first wavelength filter 350-1 can selectively filter the first optical signal or the second optical signal. The generated second reflected signal can be transmitted to the COT 110 through the third optical cable, the second RN 120-2 and the second optical cable.

[0116] As reference Figure 4As described above, since the third bandpass filter 330 of the second RN 120 - 2 is connected along the “W” direction of the second RN 120 - 2 and the fourth bandpass filter 340 is connected along the “E” direction of the second RN 120 - 2 , the third and fourth reflected signals can be generated and transmitted to the COT 110 .

[0117] Therefore, the controller 250 is only unable to receive the first reflected signal among the first to fourth reflected signals. In this case, the controller 250 may determine that there is an error in the connection direction of the first RN 120-1 and the second RN 120-2 is connected normally.

[0118] Reference Fig. 9 , showing a case where the “E” direction of the COT 110 is connected to the “W” direction of the second RN 120 - 2 , and the “W” direction of the COT 110 is connected to the “W” direction of the first RN 120 - 2 (Example 6).

[0119] This situation is relative to Figure 8 In this example, only the connection order of the first RN 120-1 and the second RN 120-2 is changed, so the controller 250 is only unable to receive the first reflected signal among the first reflected signal to the fourth reflected signal. Therefore, the controller 250 can determine that there is an error in the connection direction of the first RN 120-1 and the second RN 120-2 is connected normally.

[0120] Reference Fig.10 , shows a case where the "E" direction of COT 110 is connected to the "W" direction of the first RN 120-1, and the "W" direction of COT 110 is connected to the "W" direction of the second RN 120-2 (Example 7). In this case, COT 110 and the first RN 120-1 can be connected via a first optical cable, and COT 110 and the second RN 120-2 can be connected via a second optical cable.

[0121] As reference Figure 4 As described above, the first bandpass filter 310 of the first RN 120 - 1 is connected along the “W” direction of the first RN 120 - 1 , and the second bandpass filter 320 is connected along the “E” direction of the first RN 120 - 1 , thereby generating a first reflection signal and a second reflection signal and transmitting them to the COT 110 .

[0122] Furthermore, since the third bandpass filter 330 of the second RN 120-2 is connected along the "E" direction of the second RN 120-2, no reflection signal is generated when the second WDM signal is input to the third bandpass filter 330. The third wavelength filter 350-3 at the rear end of the third bandpass filter 330 can only filter the third optical signal, so the second optical signal or the fourth optical signal of the second WDM signal cannot be filtered, and thus no reflection signal is generated.

[0123] On the other hand, since the fourth bandpass filter 340 of the second RN 120-2 is connected along the "W" direction of the second RN 120-2, when the first WDM signal is input to the fourth bandpass filter 340, the third reflected signal will not be generated through the fourth wavelength filter 350-4 and the fourth signal reflector 360-4 at the rear end of the fourth bandpass filter 340. This is because the fourth wavelength filter 350-4 can selectively filter the third optical signal or the fourth optical signal. The generated third reflected signal can be transmitted to the COT 110 through the third optical cable, the first RN 120-1 and the first optical cable.

[0124] As described above, the controller 250 is only unable to receive the fourth reflected signal among the first to fourth reflected signals. Therefore, the controller 250 can determine that the first RN 120-1 is connected normally and only the second RN 120-2 has a connection direction error.

[0125] Reference Fig.11 , shows a case where the “E” direction of the COT 110 is connected to the “E” direction of the second RN 120 - 2 , and the “W” direction of the COT 110 is connected to the “E” direction of the first RN 120 - 1 (Example 8).

[0126] This situation is relative to Fig.10 In this example, only the connection order of the first RN 120-1 and the second RN 120-2 is changed. Therefore, in this example, the controller 250 is only unable to receive the fourth reflection signal from the first reflection signal to the fourth reflection signal. Therefore, the controller 250 can determine that the first RN 120-1 is connected normally and only the second RN 120-2 has a connection direction error.

[0127] Reference Fig.12 , shows a case where the “E” direction of the COT 110 is connected to the “E” direction of the first RN 120 - 1 , and the “W” direction of the COT 110 is connected to the “W” direction of the second RN 120 - 2 (Example 9).

[0128] As reference Figure 8 and Fig.10In the described embodiment, this example is a case where the connection directions of the first RN 120-1 and the second RN 120-2 are both reversed, so the first reflection signal and the fourth reflection signal are not generated, but only the second reflection signal and the third reflection signal are generated.

[0129] Therefore, the controller 250 may determine that both the first RN 120 - 1 and the second RN 120 - 2 have connection direction errors.

[0130] Reference Fig.13 , showing a case where the “E” direction of the COT 110 is connected to the “E” direction of the second RN 120 - 2 , and the “W” direction of the COT 110 is connected to the “W” direction of the first RN 120 - 2 (Example 10).

[0131] This situation is relative to Fig.12 In this example, only the connection order of the first RN 120-1 and the second RN 120-2 is changed. Therefore, in this example, the controller 250 can only receive the second reflection signal and the third reflection signal from the first reflection signal to the fourth reflection signal. Therefore, the controller 250 can determine that both the first RN 120-1 and the second RN 120-2 have connection direction errors.

[0132] The monitoring table (refer to Fig.14 ) may be pre-stored in a storage space (not shown) having the controller 250, and the controller 250 may monitor the connection status of the RNs 120-1 to 120-n connected to the COT 110 by comparing the received reflection signal with the monitoring table.

[0133] Therefore, according to the present disclosure, the connection status between the optical communication devices (ie, the COT 110 and the RNs 120 - 1 to 120 - n ) can be effectively monitored remotely without requiring an on-site visit by an administrator.

[0134] It will be appreciated that, although the foregoing description has been made with reference to preferred embodiments of the present disclosure, those skilled in the art may make various modifications and changes to the present disclosure without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

Claims

1. An optical communication device, which is an optical communication device of an optical ring network, comprising: A first optical signal processing unit, which outputs a first optical signal of a first wavelength; a first multiplexer / demultiplexer, outputting the first optical signal in a first direction, and receiving and outputting a first reflected signal, wherein the first reflected signal is a signal after the first optical signal is reflected; A second optical signal processing unit, which outputs a second optical signal of a second wavelength; a second multiplexer / demultiplexer, outputting the second optical signal in a second direction opposite to the first direction, and receiving and outputting a second reflected signal, where the second reflected signal is a signal after the second optical signal is reflected; as well as A controller analyzes a connection status of a first remote optical communication device to which the first optical signal and the second optical signal are assigned based on the first reflected signal and the second reflected signal.

2. The optical communication device according to claim 1, wherein: The first remote optical communication device is configured to reflect the first optical signal to generate the first reflected signal, reflect the second optical signal to generate the second reflected signal, and transmit the generated first reflected signal and second reflected signal to the optical communication device. Furthermore, the first long-distance optical communication device is configured to generate a corresponding reflection signal only when the first optical signal or the second optical signal is received in a preset direction of the first direction and the second direction.

3. The optical communication device according to claim 1, wherein: The optical communication device further comprises: a third optical signal processing unit, configured to output a third optical signal of a third wavelength to the first multiplexer / demultiplexer; and a fourth optical signal processing unit, outputting a fourth optical signal of a fourth wavelength to the second multiplexer / demultiplexer, The first multiplexer / demultiplexer multiplexes the first optical signal and the third optical signal and outputs them in the first direction, and receives a third reflected signal and outputs it to the controller, wherein the third reflected signal is a signal after the third optical signal is reflected. The second multiplexer / demultiplexer multiplexes the second optical signal and the fourth optical signal and outputs them in the second direction, and receives a fourth reflected signal and outputs it to the controller, wherein the fourth reflected signal is a signal after the fourth optical signal is reflected. The controller analyzes a connection state of a second long-distance optical communication device to which the third optical signal and the fourth optical signal are assigned based on the third reflected signal and the fourth reflected signal.

4. The optical communication device according to claim 3, wherein: The second remote optical communication device is configured to reflect the third optical signal to generate the third reflected signal, reflect the fourth optical signal to generate the fourth reflected signal, and transmit the third reflected signal and the fourth reflected signal to the optical communication device. Furthermore, the second long-distance optical communication device is configured to generate a corresponding reflection signal only when the third optical signal or the fourth optical signal is received in a preset direction of the first direction and the second direction.

5. An optical communication system, which is an optical communication system composed of an optical ring network, comprising: a first optical communication device, transmitting a first optical signal of a first wavelength in a first direction, and transmitting a second optical signal of a second wavelength in a second direction opposite to the first direction; as well as a second optical communication device, when receiving the first optical signal, reflecting the first optical signal to generate a first reflected signal, when receiving the second optical signal, reflecting the second optical signal to generate a second reflected signal, and transmitting the first reflected signal and the second reflected signal to the first optical communication device, The first optical communication device analyzes a connection state of the second optical communication device based on the first reflected signal and the second reflected signal.

6. The optical communication system according to claim 5, wherein: The second optical communication device is configured to generate a corresponding reflection signal only when the first optical signal or the second optical signal is received in a preset direction of the first direction and the second direction.

7. The optical communication system according to claim 5, wherein: The first optical communication device transmits a third optical signal of a third wavelength in the first direction, and transmits a fourth optical signal of a fourth wavelength in the second direction, The optical communication system further comprises: a third optical communication device, when receiving the third optical signal, reflecting the third optical signal to generate a third reflected signal, when receiving the fourth optical signal, reflecting the fourth optical signal to generate a fourth reflected signal, and transmitting the third reflected signal and the fourth reflected signal to the first optical communication device, The first optical communication device analyzes a connection state of the third optical communication device based on the third reflected signal and the fourth reflected signal.

8. The optical communication system according to claim 7, wherein: The third optical communication device is configured to generate a corresponding reflection signal only when the third optical signal or the fourth optical signal is received in a preset direction of the first direction and the second direction.

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