GPS information transmission method for optical communication device

Abstract

To provide a method for transmitting GPS information of an optical communication device.SOLUTION: An optical communication device includes: a GPS receiver to receive a GPS signal from a satellite and output the GPS signal; a main controller to generate and output synchronization data based on the GPS signal; and an optical transceiver to generate an optical signal by superposing input payload data and the synchronization data, and to output the optical signal. A first communication channel corresponding to the payload data and a second communication channel corresponding to the synchronization data are different communication channels. According to embodiments, GPS information for synchronization together with payload data, which is information to be transmitted, may be efficiently transmitted between optical communication devices located in remote locations without separate wavelength allocation and connection of an optical cable, by using an AMCC.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for transmitting GPS information from an optical communication device. [Background technology]

[0002] A base station installed to provide mobile communication services connects a digital unit (DU) with digital processing capabilities and a radio unit (RU) with radio signal processing capabilities via an access network. The DU located in the central station is connected to multiple RUs installed at cell sites via dedicated lines. Typically, one DU and one RU are connected via a single optical cable. Therefore, the DU located in the central station and multiple RUs distributed at cell sites are connected by building separate access networks with dedicated lines.

[0003] The DU located in the central station synchronizes the communication network using GPS signals transmitted from multiple RUs. To achieve this, a separate wavelength for transmitting GPS signals has been established between the DU and the RU. 、 GPS signals were transmitted and received. In this case, the allocation of additional wavelengths for the transmission of GPS signals allowed payload This reduces the radio resources for data transmission. Therefore, a method of connecting a separate optical cable for transmitting GPS signals between the DU and RU has been used. However, this method requires an optical cable and a configuration for transmitting GPS signals to the optical cable, which increases manufacturing and installation costs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 8,582,607 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to solve the above-mentioned problems, the present invention provides a method for transmitting GPS information between optical communication devices, which can effectively transmit and receive GPS information for synchronization between optical communication devices located at remote locations without using an optical cable or allocating a separate wavelength.

[0006] The technical problems to be solved by the technical idea of ​​the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a GPS receiver for receiving and outputting GPS signals from satellites, a main controller for generating and outputting synchronization data based on the GPS signals, and a payload an optical transceiver that generates an optical signal by superimposing data and the synchronization data, and outputs the optical signal; payload An optical communication device is disclosed, wherein a first communication channel corresponding to data and a second communication channel corresponding to the synchronization data are different communication channels.

[0008] According to an exemplary embodiment, the optical transceiver includes a controller that receives the synchronization data and outputs the synchronization data as auxiliary control and management data for controlling and managing optical transceivers on other optical communication devices; payload a transmitter that superimposes data and the synchronization data to generate the optical signal.

[0009] According to an exemplary embodiment, the main controller extracts a navigation message from the GPS signal to generate the synchronization data, and transmits the synchronization data to the optical transceiver.

[0010] According to an exemplary embodiment, the second communication channel is an Auxiliary Management and Control Channel (AMCC).

[0011] According to another aspect of the present invention, a first optical communication device is connected to a first optical cable. payload a first optical transceiver that receives a first optical signal in which data and first synchronization data are overlapped, separates the first synchronization data from the first optical signal, and outputs the separated first synchronization data; and a second optical communication device connected to the first optical transceiver through a second optical cable. payload a second optical transceiver for receiving a second optical signal in which data and second synchronization data are superimposed, and for separating and outputting the second synchronization data from the second optical signal; and a main controller for analyzing the first synchronization data and the second synchronization data to extract a reference synchronization signal. payload The data and the first synchronization data are received through different communication channels, and the second synchronization data are received through different communication channels. payload An optical communication device is disclosed, wherein the data and the second synchronization data are received through different communication channels.

[0012] According to an exemplary embodiment, the main controller selects one of the first synchronization data and the second synchronization data based on an analysis result of the first synchronization data and the second synchronization data, and extracts the reference synchronization signal from the selected synchronization data.

[0013] According to an exemplary embodiment, the first synchronization data includes a first navigation message extracted from a GPS signal received from the first other optical communication device, and the second synchronization data includes a second navigation message extracted from a GPS signal received from the second other optical communication device.

[0014] According to an exemplary embodiment, the first synchronization data and the second synchronization data are received through an AMCC.

[0015] According to yet another aspect of the present invention, payloadand at least one first optical communication device that transmits an optical signal on which data and synchronization data corresponding to a GPS signal are superimposed, and a second optical communication device that receives the optical signal from the at least one first optical communication device, separates the synchronization data from the optical signal, and extracts a reference synchronization signal based on the synchronization data. payload An optical communication system is disclosed in which data and the synchronization data are transmitted over different communication channels.

[0016] According to an exemplary embodiment, the synchronization data includes a navigation message extracted from the GPS signal.

[0017] According to an exemplary embodiment, the first optical communication device is configured in multiple units, and the second optical communication device analyzes synchronization data transmitted from each of the multiple first optical communication devices and extracts the reference synchronization signal from selected synchronization data based on the analysis results.

[0018] According to an exemplary embodiment, the synchronization data is transmitted over AMCC. [Effects of the Invention]

[0019] According to an embodiment of the present invention, between optical communication devices located at remote locations, GPS information for synchronizing a network linked to the optical communication devices is transmitted using an auxiliary control management channel for control management between optical transceivers, thereby enabling efficient transmission of GPS information without resource loss due to allocation of a separate wavelength or increased manufacturing and installation costs due to optical cables.

[0020] The effects obtained by the embodiments according to the technical concept of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0021] [Figure 1]1 is a diagram illustrating an optical communication system according to an embodiment of the present invention; [Figure 2] 2 is a block diagram showing in more detail the main parts of an optical communication device in an optical communication system according to an embodiment of the present invention. FIG. [Figure 3] FIG. 1 is a schematic diagram illustrating the configuration of a GPS signal. DETAILED DESCRIPTION OF THE INVENTION

[0022] The technical concept of the present invention can be variously modified and can have various embodiments, and therefore, specific embodiments are illustrated in the drawings and will be described in detail. However, this is not intended to limit the technical concept of the present invention to the specific embodiments, and it should be understood that the technical concept of the present invention includes all modifications, equivalents, and alternatives that fall within the scope of the technical concept of the present invention.

[0023] In explaining the technical concept of the present invention, if a detailed description of the related prior art is deemed to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Furthermore, numbers (e.g., 1, 2, etc.) used in the description of this specification are merely identification symbols for distinguishing one component from another.

[0024] Furthermore, in this specification, when a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but may also be coupled or connected via another component in between, unless otherwise specified to the contrary.

[0025] In addition, terms such as "module", "device" and "subsystem" used in this specification refer to a unit that processes at least one function or operation, and this may be embodied in hardware or software, such as a processor, microprocessor, microcontroller, CPU (Central Processing Unit), GPU (Graphics Processing Unit), APU (Accelerate Processor Unit), DSP (Drive Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or a combination of hardware and software.

[0026] It should be understood that the division of components in this specification merely represents a division according to the main function of each component. That is, two or more components described below may be combined into one component, or one component may be divided into two or more components according to further subdivided functions. It goes without saying that each component described below may perform some or all of the functions of other components in addition to its own main function, and that some of the main functions of each component may be exclusively performed by other components.

[0027] Hereinafter, various embodiments according to the technical concept of the present invention will be described in detail.

[0028] FIG. 1 is a diagram illustrating an optical communication system according to an embodiment of the present invention.

[0029] 1, an optical communication system 100 according to an embodiment of the present invention includes an optical communication device 110 located at a first site and equipped with at least two optical transceivers, and a plurality of optical communication devices 120-1 and 120-2 located at second sites spaced a predetermined distance from the first site and each equipped with at least one optical transceiver. While FIG. 1 illustrates a topology in which the optical communication device 110 and the optical communication devices 120-1 and 120-2 are connected in a point-to-multipoint configuration, this is not limiting. Optical distribution networks with various topologies may also be applied between the optical communication device 110 and the optical communication devices 120-1 and 120-2.

[0030] In some embodiments, the optical communication system 100 is applied to a fronthaul transmission network of a distributed base station. In this case, the optical communication device 110 is a digital unit (DU) on the central office side, and the optical communication devices 120-1 and 120-2 are radio units (RU). However, this is not limited thereto, and the optical communication device 110 may be an optical line terminal (OLT) on the DU side, and the optical communication devices 120-1 and 120-2 may be optical network units (ONU) on the RU side.

[0031] In another embodiment, the optical communication system 100 is applied to a distributed antenna system (DAS) for eliminating shadow areas of a base station, in which the optical communication device 110 is a headend unit, and the optical communication devices 120-1 and 120-2 are extension units or remote units. For ease of explanation, the following description will focus on an embodiment in which the optical communication device 110 is a DU and the optical communication devices 120-1 and 120-2 are a first and second RU, assuming that the optical communication system 100 is applied to the fronthaul transmission network of the distributed base station described above.

[0032] The DU 110 is located on the central office side (first site), and the first and second RUs 120-1 and 120-2 are located at each remote cell site (second site), and the DU 110 and the first and second RUs 120-1 and 120-2 are connected to each other via corresponding optical transceivers and optical cables.

[0033] The DU 110 receives information for synchronization based on GPS signals (hereinafter referred to as 'synchronization data') from the first and second RUs 120-1 and 120-2, respectively, and synchronizes the communication network using the synchronization data.

[0034] For example, each of the first and second RUs 120-1 and 120-2 includes a GPS receiver to receive a GPS signal from a satellite SL, extracts information necessary for generating a reference synchronization signal (e.g., a clock signal) from the received GPS signal, generates the synchronization data, and then transmits the synchronization data to the DU 110. At this time, each of the first and second RUs 120-1 and 120-2 receives a reference synchronization signal corresponding to the mobile communication service signal to be transmitted. payload The synchronization data is transmitted to the DU 110 through a communication channel separate from the channel for transmitting data. The DU 110 then extracts a synchronization signal using the received synchronization data to synchronize the communication network.

[0035] Hereinafter, the operation of the DU 110 receiving synchronization data from the first and second RUs 120-1 and 120-2 will be described in detail with reference to FIGS.

[0036] FIG. 2 is a block diagram showing in more detail the main parts of the optical communication device in the optical communication system according to one embodiment of the present invention, and FIG. 3 is a schematic diagram of the GPS signal. 2, among the multiple optical communication devices constituting optical communication system 100 according to one embodiment of the present invention, first RU 120-1 includes GPS receiver 121, main controller (MCU) 123, and optical transceiver 1200-1. Optical transceiver 1200-1 includes controller 1210, transmitter 1230, receiver 1250, and filter 1270. The configuration and operation of second RU 120-2 are substantially the same as those of first RU 120-1, and therefore a detailed description of second RU 120-2 will be omitted.

[0037] The MCU 123 is configured to control the overall operation of the first RU 120-1, and analyzes the GPS signal received through the GPS receiver 121.

[0038] For example, the GPS receiver 121 receives and outputs a plurality of GPS signals from a plurality of satellites SL, and the MCU 123 analyzes the inputted plurality of GPS signals, analyzes the power of the inputted plurality of GPS signals, detects the GPS signal with the maximum signal power, and extracts a predetermined navigation message from the GPS signal with the maximum signal power.

[0039] 3, a GPS signal is made up of five subframes: the first subframe 310 corresponds to clock correction information, the second and third subframes 320-1 and 320-2 correspond to information about the orbit of the satellite that transmitted the GPS signal (hereinafter referred to as the "satellite"), the fourth subframe 330 corresponds to a navigation message, and the fifth subframe 340 corresponds to individual information about the satellite.

[0040] The fourth subframe 330 of the GPS signal contains information about the calendar system that allows time to be divided, and based on this information, a clock signal is extracted that is used as a reference for synchronization of the communication network.

[0041] As will be described later, in order to transmit information for synchronization using an Auxiliary Management and Control Channel (AMCC) having limited resources (bandwidth), the MCU 123 does not transmit the detected GPS signal directly, but extracts information regarding the fourth subframe 330, which is essential for synchronization, from the detected GPS signal.

[0042] As another example, the MCU 123 may extract information about the navigation message from each of the input GPS signals, i.e., the MCU 123 extracts the navigation message from all of the input GPS signals without considering the signal power of the input GPS signals.

[0043] Meanwhile, in addition to the navigation messages extracted from each of the input GPS signals, the MCU 123 extracts or generates information indicating the quality of the GPS signals, such as their power, from the GPS signals.

[0044] 2, the MCU 123 generates synchronization data including the extracted navigation message. In addition to the navigation message, the synchronization data may further include information indicating the quality of the GPS signal corresponding to the navigation message, such as signal power. The MCU 123 may generate synchronization data corresponding only to the GPS signal with the highest signal power, or may generate synchronization data corresponding to each of the received GPS signals.

[0045] The MCU 123 outputs the generated synchronization data to the controller 1210 of the optical transceiver 1200-1.

[0046] The controller 1210 is connected to the MCU 123 by wire or wirelessly, and controls the communication between the DU 110 and the first RU 120-1. payload It manages the transmission and reception of data, and the transmission and reception of control management (wavelength setting / control, communication status monitoring, etc.) information and synchronization data (hereinafter collectively referred to as first auxiliary management data).

[0047] The controller 1210 is the active component of the optical transceiver 1200-1 and controls high-speed payload It is a general term for a processor that performs various controls and processes for transmitting low-speed first auxiliary management data through the AMCC along with data, memory in which firmware, etc. are stored, etc.

[0048] The controller 1210 controls the first auxiliary management data to be transmitted to the DU 110, more specifically, to the optical transceiver 1100-1 of the DU 110, in various ways.

[0049] For example, the controller 1210 may transmit the first auxiliary management data and the second auxiliary management data through a baseband intensity modulation scheme. payload In another example, the controller 1210 controls the first auxiliary management data and the second auxiliary management data to be transmitted to the optical transceiver 1100-1 of the DU 110 simultaneously through a radio frequency pilot tone (RF pilot tone). payload The optical transceiver 1100-1 of the DU 110 controls the optical transceiver 1100-2 to superimpose the received data onto the optical transceiver 1100-1.

[0050] The baseband intensity modulation method uses the first auxiliary management data payload It is a technique to stack the data on top of the RF pilot signal. The RF pilot signal is ASK or FSK modulated first auxiliary management data. payload The transmission speed of the first auxiliary management data is payload The transmission speed of the first auxiliary management data is different from the transmission speed of the data. For example, the frequency of the first auxiliary management data is several kHz. payload The data frequency is several tens to several hundreds of MHz. The first auxiliary management data transmission and reception methods, such as baseband intensity modulation and RF pilot modulation, are already publicly known technologies, so the details thereof will be omitted.

[0051] Meanwhile, the controller 1210 controls the first auxiliary management data so that data for control management and synchronization data are transmitted together through the AMCC in a time division manner. For example, the controller 1210 modulates the data for control management and the synchronization data using ASK, FSK, etc., divides the AMCC band based on time, and controls the modulated data for control management and synchronization data to be transmitted.

[0052] As described above, the controller 1210 outputs the synchronization data to the first auxiliary management data, and the synchronization data is transmitted to the transmitter 1230 (described later). payload The data is transmitted to the optical transceiver 1100-1 of the DU 110 through a channel separate from the data. payload When an optical signal corresponding to data is transmitted to the optical transceiver 1100-1 of the DU 110 through a first communication channel corresponding to a first wavelength, an optical signal corresponding to synchronization information is transmitted to the optical transceiver 1100-1 of the DU 110 through a second communication channel (i.e., AMCC) corresponding to a second wavelength.

[0053] The transmitter 1230 receives the input payload The transmitter 1230 is configured to convert the data and / or the first auxiliary management data into an optical signal. The transmitter 1230 includes a TOSA (Transmitter Optical Sub-Assemblies) consisting of a laser diode, a laser diode driving circuit (LDD), a biasing circuit, etc. payload Data is input via the LDD.

[0054] The filter 1270 is configured to share a single optical cable between the output of the transmitter 1230 and the input of the receiver 1250 (described later). The filter 1270 transmits the optical signal output from the transmitter 1230 to the single optical cable, and transmits the received optical signal from the optical cable to the receiver 1250. Depending on the embodiment, the filter 1270 may be selectively omitted.

[0055] The receiver 1250 receives the optical signal filtered by the filter 1270 and outputs it as follows: payload The receiver 1250 separates the received signal into the received signal and second auxiliary management data (the definition of the second auxiliary management data will be described later), and outputs them in the corresponding configurations. In particular, the receiver 1250 outputs the second auxiliary management data to the controller 1210. The receiver 1250 includes a photodiode, ROSAs (Receiver Optical Sub-Assemblies) consisting of TIAs (Trans-Impedance Amplifiers), a post-amplifier, etc.

[0056] As described above, the first RU 120-1 receives GPS signals from satellites, analyzes the received GPS signals to generate synchronization data, and synchronizes the synchronization data using AMCC. payload It is transmitted to the DU 110 together with the data.

[0057] Similarly, the second RU 120-2 receives GPS signals from satellites, analyzes the received GPS signals to generate synchronization data, and synchronizes the synchronization data using AMCC. payload It is transmitted to the DU 110 together with the data.

[0058] Of the multiple optical communication devices that make up the optical communication system 100 according to one embodiment of the present invention, the DU 110 includes a main controller (MCU) 111, a memory 113, and optical transceivers 1100-1 and 1100-2. The optical transceiver 1100-1 includes a controller 1110, a receiver 1130, a transmitter 1150, and a filter 1170. The configuration and operation of the optical transceiver 1100-2 are substantially the same as those of the optical transceiver 1100-1, and therefore a detailed description of the optical transceiver 1100-2 will be omitted.

[0059] The MCU 111 of the DU 110 is configured to control the overall operation of the DU 110, and analyzes synchronization data received from the first and second RUs 120-1 and 120-2 via the corresponding optical transceivers and optical cables.

[0060] For example, the MCU 111 analyzes and compares the quality of the synchronization data received from the first and second RUs 120-1 and 120-2, respectively, to select one of them, and generates a synchronization signal based on the selected synchronization data.

[0061] The MCU 111 controls synchronization between the DU 110 and the first and second RUs 120-1 and 120-2 based on the generated synchronization signal. According to an embodiment, the MCU 111 may transmit the generated synchronization signal to other DUs communicatively connected to the DU 110 and to an interlocking network, thereby synchronizing the entire communication network.

[0062] The memory 113 is connected to the MCU 111 and is a storage means for storing various information and program commands required for the operation of the DU 110. The memory 113 also stores the synchronization data, synchronization signals, etc. The synchronization data is information received from the first and second RUs 120-1 and 120-2 via the AMCC.

[0063] The controller 1110 is connected to the MCU 111 by wire or wirelessly, and controls the communication between the DU 110 and the first RU 120-1. payload A configuration that manages the transmission and reception of data and the transmission and reception of information for control management (wavelength setting, communication status monitoring, etc.), payload In addition to the information required for data transmission and reception support management, synchronization data is also received from the first RU 120-1.

[0064] Filter 1170 and receiver 1130 filter the optical signal received from first RU 120-1 and output synchronization data to controller 1110.

[0065] Transmitter 1150 and filter 1170 then transmit to first RU 120-1. payload The data and the second auxiliary management data are superimposed to generate an optical signal, which is filtered and transmitted to the first RU 120-1.

[0066] The transmitter 1150, receiver 1130, and filter 1170 are substantially the same as the transmitter 1230, receiver 1250, and filter 1270 described above, and therefore will not be described in detail.

[0067] As described above, in the optical communication system 100 according to the embodiment of the present invention, synchronization data (based on GPS signals) for system synchronization is transmitted between optical communication devices via AMCC. Therefore, the transmission of information for synchronization is performed as follows: payload This is done without any impact on the transmission of data.

[0068] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that the present invention can be modified and changed in various ways without departing from the spirit and scope of the present invention as defined in the following claims. [Explanation of symbols]

[0069] 100 Optical Communication System 110, 120 Optical communication device 1100, 1200 optical transceiver

Claims

1. An optical communication device, a GPS receiver that receives and outputs GPS signals from satellites; a main controller that generates and outputs synchronization data based on the GPS signal; an optical transceiver that generates an optical signal by superimposing input payload data and the synchronization data, and outputs the optical signal; the first communication channel corresponding to the payload data and the second communication channel corresponding to the synchronization data are different communication channels; The main controller Controlling modulation of the synchronization data and the control and management data; transmitting the modulated synchronization data and the modulated control and management data over the second communication channel; It is configured as The optical communication device, wherein the control management data includes information regarding wavelength setting and control, and monitoring of communication conditions between the optical communication device and other optical communication devices.

2. a controller configured to receive the synchronization data and output the synchronization data as auxiliary control and management data for controlling and managing the optical transceiver of the other optical communication device; a transmitter that superimposes the input payload data and the synchronization data to generate the optical signal; 2. The optical communication device according to claim 1, wherein the auxiliary control management data includes the synchronization data and the control management data.

3. 2. The optical communication device according to claim 1, wherein the main controller extracts a navigation message from the GPS signal to generate the synchronization data, and transmits the synchronization data to the optical transceiver.

4. 2. The optical communication device according to claim 1, wherein the second communication channel is an AMCC (Auxiliary Management and Control Channel).

5. An optical communication device, a first optical transceiver that receives a first optical signal, in which first payload data and first synchronization data are superimposed, from a first other optical communication device connected via a first optical cable, and separates and outputs the first synchronization data from the first optical signal; a second optical transceiver that receives a second optical signal, in which second payload data and second synchronization data are superimposed, from a second other optical communication device connected via a second optical cable, and separates and outputs the second synchronization data from the second optical signal; a main controller that analyzes the first synchronization data and the second synchronization data to extract a reference synchronization signal; the first payload data and the first synchronization data are received through different communication channels; the second payload data and the second synchronization data are received through different communication channels; each of the first synchronization data and the second synchronization data is modulated with control and management data and received together; The optical communication device, wherein the control management data includes information regarding wavelength setting and control, and monitoring of communication conditions between the optical communication device and other optical communication devices.

6. 6. The optical communication device of claim 5, wherein the main controller selects one of the first synchronization data and the second synchronization data based on an analysis result of the first synchronization data and the second synchronization data, and extracts the reference synchronization signal from the selected synchronization data.

7. the first synchronization data includes a first navigation message extracted from a GPS signal received from the first other optical communication device; 6. The optical communication device according to claim 5, wherein the second synchronization data includes a second navigation message extracted from a GPS signal received from the second other optical communication device.

8. The optical communication device of claim 5, wherein the first synchronization data and the second synchronization data are received through an Auxiliary Management and Control Channel (AMCC).

9. at least one first optical communication device for transmitting an optical signal on which payload data and synchronization data corresponding to a GPS signal are superimposed; a second optical communication device that receives the optical signal from the at least one first optical communication device, separates the synchronization data from the optical signal, and extracts a reference synchronization signal based on the synchronization data; the payload data and the synchronization data are transmitted through different communication channels; The synchronization data is modulated and transmitted together with the control and management data; An optical communication system, wherein the control management data includes information regarding wavelength setting and control, and monitoring of communication status between the at least one optical communication device and the second optical communication device.

10. 10. The optical communication system of claim 9, wherein the synchronization data includes a navigation message extracted from the GPS signal.

11. The first optical communication device is composed of a plurality of devices, 10. The optical communication system of claim 9, wherein the second optical communication device analyzes synchronization data transmitted from each of the plurality of first optical communication devices, and extracts the reference synchronization signal from selected synchronization data based on the analysis result.

12. The optical communication system of claim 9, wherein the synchronization data is transmitted through an Auxiliary Management and Control Channel (AMCC).

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