Method for synchronizing communication network and network management system

Abstract

To provide a method of synchronizing a communication network and a network management system, capable of selecting a synchronization source to be used for synchronization of a communication network according to a priority based on a quality parameter of synchronization sources and a capacity parameter of communication nodes connected to the synchronization sources.SOLUTION: A method comprises the steps of: obtaining a quality parameter of at least two synchronization sources connected to communication nodes in a communication network and a capacity parameter of the communication nodes connected to the synchronization sources; selecting a synchronization source to be used for synchronization of the communication network from among the at least two synchronization sources, according to a priority based on the obtained quality parameter and capacity parameter; and performing synchronization of the communication network using a synchronization signal provided from the selected synchronization source.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a network management system and a method for synchronizing a communication network, and more particularly to a network management system and a method for synchronizing a communication network, capable of selecting a synchronization source to be used for synchronizing the communication network according to a priority based on a quality parameter of the synchronization source and a capacity parameter of a communication node connected to the synchronization source. [Background technology]

[0002] A distributed antenna system (DAS) currently available on the market has a configuration in which a headend device receives external reference clock information and transmits the reference clock to other nodes (eg, extension devices or remote devices).

[0003] However, since the head end device is quite large in size and weight and needs to be supplied with a separate power source, it is generally arranged in a separate space in the building in which the distributed antenna system is installed. In order to receive external reference clock information in such a structure, it is structurally inefficient in that a clock source arranged far away and the head end device must be connected by a cable. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem to be solved by the present invention is to provide a network management system and a method for synchronizing a communication network, which can select a synchronization source to be used for synchronizing the communication network based on a priority order based on a quality parameter of the synchronization source and a capacity parameter of a communication node connected to the synchronization source. [Means for solving the problem]

[0005] A method for synchronizing a communication network according to an embodiment of the present invention includes the steps of acquiring quality parameters of at least two or more synchronization sources connected to a communication node in the communication network and capacity parameters of the communication nodes connected to the synchronization sources, selecting a synchronization source to be used for synchronizing the communication network from the at least two or more synchronization sources based on a priority order based on the acquired quality parameters and capacity parameters, and synchronizing the communication network using a synchronization signal provided by the selected synchronization source.

[0006] In some embodiments, the quality parameter is determined based on at least one of temperature stability, operating temperature range, hierarchical level, frequency quality, and phase quality.

[0007] In some embodiments, the capacity parameter is determined based on a maximum number of slave nodes that the at least two communication nodes can accommodate.

[0008] In some embodiments, the quality parameters and the capacity parameters are stored in the form of a table in a network management system that manages the communication network.

[0009] In some embodiments, the priority is dynamically determined based on the quality parameter and the capacity parameter.

[0010] In some embodiments, the quality parameter is based on at least one of a holdover time, temperature stability, operating temperature range, stratum level, frequency quality, and phase quality of the synchronization source.

[0011] In some embodiments, the capacity parameter is determined based on the number of slave nodes that can be accommodated when the communication node to which the synchronization source is coupled operates as a master node.

[0012] In some embodiments, the method of synchronising a communications network further comprises receiving the capacity parameters from each of the communications nodes in the communications network.

[0013] In some embodiments, the priority is determined by reflecting weights on each of the quality and capacity parameters.

[0014] In some embodiments, the method for synchronizing the communications network further includes, after the step of selecting a synchronization source to be used for synchronizing the communications network, a step of determining a synchronization mode for each of the communications nodes based on the selected synchronization source and characteristic information of each of the communications nodes in the communications network.

[0015] In some embodiments, the characteristic information of each of the communication nodes includes at least one of whether each of the communication nodes supports a specific synchronization mode, whether the connected communication nodes can be tracked, the capacity of a slave node, the number of communication nodes currently connected to the communication node, and the number of slave nodes corresponding to the communication node.

[0016] In some embodiments, the number of communication nodes currently connected to the communication node is obtained using a connection tracking function of the IEEE 1588 PTP protocol.

[0017] In some embodiments, the synchronization mode is a transparent clock mode or a boundary clock mode of the IEEE 1588 PTP protocol.

[0018] In some embodiments, the communications network comprises at least one of a headend device, an extension device, and a remote device, and at least one of the synchronization sources is coupled to the extension device or the remote device.

[0019] In some embodiments, the method for synchronizing the communication network further includes the steps of monitoring whether the selected synchronization source fails, and, if the selected synchronization source fails, selecting another synchronization source to use for synchronizing the communication network according to a priority recalculated based on the quality parameter and the capacity parameter.

[0020] In some embodiments, the method for synchronizing the communication network further includes a step of determining, when the failure of the failed synchronization source is restored, whether to use the synchronization source selected before the failure occurred for synchronizing the communication network.

[0021] In some embodiments, when the failure of the failed synchronization source is restored, the method further includes a step of comparing a difference between the quality of the synchronization source selected before the failure occurred and the quality of the other synchronization sources, and determining which synchronization source to use for synchronizing the communication network.

[0022] A network management system according to an embodiment of the present invention includes a memory that acquires and stores quality parameters and capacity parameters of at least two or more synchronization sources connected to communication nodes in a communication network, a processor that selects a synchronization source to be used for synchronizing the communication network from the at least two or more synchronization sources based on a priority order based on the quality parameters and the capacity parameters, and a communication interface that transmits a setting signal to the communication network for synchronizing the communication network using a synchronization signal provided by the selected synchronization source. Effect of the Invention

[0023] The method and apparatus according to an embodiment of the present invention can provide an optimal synchronization signal that matches the state of the synchronization source and the conditions of the communication network by selecting a synchronization source to be used for synchronizing a communication network according to a priority based on a quality parameter of the synchronization source and a capacity parameter of a communication node connected to the synchronization source. [Brief description of the drawings]

[0024] In order to more fully understand the drawings referred to in the detailed description of the invention, a brief description of each of the drawings is provided. [Figure 1] 1 is a conceptual diagram of a communication system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram of one embodiment of the distributed antenna system shown in FIG. [Diagram 3] 2 is a block diagram of one embodiment of the network management system shown in FIG. 1. [Figure 4] 4 is a table illustrating parameters corresponding to each communication node coupled to a synchronization source according to one embodiment. [Diagram 5] 4 is a table showing characteristic information of each communication node according to one embodiment. [Figure 6] 2 is a flow chart of a synchronization method for a communication network according to an embodiment of the present invention; [Figure 7] 7 is a diagram showing an example in which a synchronization mode of a communication node is set according to the synchronization method of the communication network of FIG. 6; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The technical idea of ​​the present invention can be modified in various ways 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 idea of ​​the present invention to the specific embodiments, and it should be understood that the technical idea of ​​the present invention includes all modifications, equivalents, and alternatives included in the scope of the technical idea of ​​the present invention.

[0026] In describing the technical concept of the present invention, if a detailed description of the related known technology is deemed to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, numbers (e.g., 1, 2, etc.) used in the description of this specification are merely identification symbols for distinguishing one component from another.

[0027] In addition, 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 unless specifically stated to the contrary, it may also be coupled or connected via another component in between.

[0028] In addition, terms such as "unit," "device," "child," and "module" used in this specification refer to a unit that processes at least one function or operation, which may be embodied in hardware, software, or a combination of hardware and 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), or FPGA (Field Programmable Gate Array), and may be embodied in a form combined with a memory that stores data necessary for processing at least one function or operation.

[0029] It is to be noted that the components in this specification are merely classified 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 some of the main functions of each component may be exclusively performed by other components.

[0030] FIG. 1 is a conceptual diagram of a communication system according to an embodiment of the present invention.

[0031] Referring to FIG. 1, a communication system 10 includes a core network 50, a base station (Base Transceiver Station, BTS) 100, a distributed antenna system (DAS) 200 that relays communication signals of the base station 100, and an NMS (Network Management System) 300 that manages and monitors the distributed antenna system 200.

[0032] According to an embodiment, the communication system 10 is divided into a core network 50, base stations 100 constituting an access network for connecting user terminals to the core network 50, and a distributed antenna system 200.

[0033] The distributed antenna system 200 is illustrated as an example of a communications network and can directly perform at least some of the functions of the base station 100 .

[0034] Depending on the embodiment, the distributed antenna system 200 may form one communication network together with the network management system 300 .

[0035] The distributed antenna system 200 comprises a headend device 210 communicatively coupled to the base station 100 and constituting a headend node, a plurality of remote devices 220a, 220b, 220c, 220d constituting remote nodes and coupled to other remote nodes or located at respective remote service locations and communicatively coupled to user terminals, and extension devices 230a and 230b constituting extended nodes.

[0036] In some embodiments, the distributed antenna system 200 is embodied as an analog distributed antenna system.

[0037] In other embodiments, the distributed antenna system 200 may be implemented as a digital distributed antenna system, or in some cases, as a mixed type (e.g., some nodes perform analog processing and the remaining nodes perform digital processing).

[0038] Meanwhile, FIG. 1 shows an example of a topology of the distributed antenna system 200, and the distributed antenna system 200 can be modified in various ways in consideration of the particularities of the installation area and application field (e.g., in-building, subway, hospital, stadium, etc.).

[0039] In the distributed antenna system 200, the extension devices 230a and 230b are utilized when the number of branches of the head-end device 210 is limited compared to the number of remote devices that need to be installed.

[0040] To explain each node in the distributed antenna system 200 and its function in more detail, the head-end device 210 serves as an interface with the base station.

[0041] Depending on the embodiment, the headend unit 210 may be coupled to multiple base stations.

[0042] According to an embodiment, the headend device 210 is embodied as a main headend device and a sub-headend device, and is connected to base stations for each service frequency band or each sector of a specific operator, and in some cases, the main headend device may supplement its coverage with the sub-headend device.

[0043] Generally, RF (Radio Frequency) signals transmitted from a base station are high-power signals, so the head-end device 210 attenuates such high-power RF signals to signals with power suitable for processing at each node. The head-end device 210 reduces high-power RF signals for each frequency band or each sector to low power. The head-end device 210 combines the low-power RF signals and distributes the combined signals to the extension device 230a or the remote device 220a.

[0044] Depending on the embodiment, the headend equipment 210 may receive communication signals in a digital format (e.g., Common Public Radio Interface (CPRI), Open Radio Interface (ORI), Open Baseband Remote Radiohead Interface (OBSAI), or e-CPRI, etc.) directly from the base station 100.

[0045] Each of the remote devices 220a, 220b, 220c, and 220d separates the transferred and combined signals into frequency bands and performs signal processing such as amplification, etc. Thus, each of the remote devices 220a, 220b, 220c, and 220d transmits base station signals to user terminals within its own service coverage through a service antenna (not shown).

[0046] The remote device 220a and the remote device 220b are connected via an RF cable or wireless communication, and multiple remote devices are connected in a cascade structure as necessary.

[0047] The extender device 230a transmits the transmitted and combined signal to the remote device 220c that is coupled to the extender device 230a.

[0048] The extension device 230b is connected to one end of the remote device 220a and receives a signal transmitted from the headend device 210 via the remote device 220a in downlink communication. At this time, the extension device 230b transmits the received signal again to the remote device 220d connected to the rear end of the extension device 230b.

[0049] Meanwhile, the base station 100 and the headend device 210 are connected to each other via an RF cable, an optical cable, or an Ethernet cable (e.g., a twisted cable, a UTP cable), and at the lower end of the headend device 210, except between the remote device 220a and the remote device 220b, they are connected to each other via an optical cable or an Ethernet cable (e.g., a twisted cable, a UTP cable), and the signal transmission medium and communication method between each node can be variously modified.

[0050] According to an embodiment, when the internal components of the distributed antenna system 200 are connected to each other by optical cables, the headend device 210, the remote devices 220a, 220b, 220c, 220d, and the extension devices 230a and 230b may be equipped with optical transceiver modules for transmitting and receiving optical type signals through electrical-to-optical conversion / optical-to-electrical conversion, or may include WDM (Wavelength Division Multiplexing) elements when the nodes are connected by a single optical cable.

[0051] The distributed antenna system 200 is connected to an external management device (not shown) such as a Network Management System (NMS) 300 or a Network Operation Center (NOC) (not shown) through a network, allowing an administrator to remotely monitor the status and problems of each node in the distributed antenna system and remotely control the operation of each node.

[0052] In FIG. 1, for ease of explanation, synchronization sources coupled to the communication nodes have been omitted.

[0053] FIG. 2 is a block diagram of one embodiment of the distributed antenna system shown in FIG.

[0054] 1 and 2, distributed antenna system 200A includes headend unit 210, remote units 220-1 through 220-4, extension units 230-1 and 230-2, smorcell 400, and synchronization sources 500-1 through 500-3.

[0055] Distributed antenna system 200A, an example of a communications network, includes multiple communications nodes (eg, headend device 210, remote devices 220-1 through 220-4, and extension devices 230-1 and 230-2).

[0056] The distributed antenna system 200A includes at least two or more communication nodes (eg, 220-1, 220-3, and 220-4) to which synchronization sources 500-1 through 500-3 are coupled.

[0057] The network management system 300, which manages the communication nodes (e.g., 210, 220-1 to 220-4, 230-1 to 230-2, 400) of the distributed antenna system 200A, or the headend device 210 of the distributed antenna system 200A selects a synchronization source to be used for synchronization of the distributed antenna system 200A from the synchronization sources 500-1 to 500-3 connected to the communication nodes.

[0058] According to an embodiment, the network management system 300 or the headend device 210 acquires quality parameters of the synchronization sources (e.g., 500-1 to 500-3) and capacity parameters of the communication nodes (e.g., 220-1, 220-3, 220-4) connected to the synchronization sources (e.g., 500-1 to 500-3), and prioritizes the synchronization sources (e.g., 500-1 to 500-3) based on the acquired quality parameters and capacity parameters.

[0059] The quality parameters refer to various parameters that indicate the accuracy and stability of the synchronization signal provided by the synchronization source.

[0060] For example, the quality parameter may be based on at least one of a holdover time, temperature stability, operating temperature range, stratum level, frequency quality, and phase quality of the synchronization source.

[0061] For example, frequency quality may be a quality indicator indicating the number of signals that experience frequency errors out of a reference number of signals (eg, 16 ppb).

[0062] For example, the phase quality is a quality index indicating the time range over which the phase error occurs (eg, + / - 5ns).

[0063] The capacity parameter is determined based on the number of slave nodes that can be accommodated when the communication node to which the synchronization source is connected operates as a master node.

[0064] For example, the capacity parameter is determined based on the maximum number of slave nodes that can be accommodated when the communication node operates as a master node.

[0065] Examples of quality and capacity parameters are discussed below in conjunction with FIG.

[0066] In some embodiments, priorities are dynamically determined based on changing quality and capacity parameters.

[0067] The network management system 300 or the head-end device 210 selects a synchronization source to be used for synchronization from the multiple synchronization sources 500-1 to 500-3 according to a set priority.

[0068] The synchronization sources 500-1 to 500-3 generate synchronization signals.

[0069] According to an embodiment, the synchronization sources 500-1 to 500-3 may include a Global Positioning System (GPS) antenna. In this case, the synchronization source 500 receives a GPS signal from outside the distributed antenna system 200A and uses the received GPS signal as a synchronization signal.

[0070] Depending on the embodiment, the synchronization sources 500-1 to 500-3 may use synchronization clock sources such as a Stratum 1 Primary Reference Clock (PRC), a Stratum 1 Primary Reference Source (PRS), a Stratum 2 Synchronization Supply Unit (SSU), a Stratum 2 Stand-Alone Synchronization Equipment (SASE), a Stratum 3 Building Integrated Timing Supply (BITS), and a Stratum 3 SDH Equipment Clock (SEC).

[0071] Depending on the embodiment, at least one of the synchronization sources 500-1 to 500-3 may be coupled to an extension device or a remote device.

[0072] Fig. 3 is a block diagram of an embodiment of the network management system shown in Fig. 1. Fig. 4 is a table showing parameters corresponding to each communication node connected to a synchronization source according to an embodiment. Fig. 5 is a table showing characteristic information of each communication node according to an embodiment.

[0073] 1 to 3, the network management system 300 includes a memory 310, a processor 320, a communication interface 330, a clock policy handler 340, a clock source monitor 350, and a communication node monitor 360.

[0074] The memory 310 stores data necessary for the operation of the network management system 300 .

[0075] Depending on the embodiment, the memory 310 may store data necessary for selecting a synchronization source to be used for synchronizing the distributed antenna system 200 from among multiple synchronization sources (e.g., 500-1 to 500-3) in a communication network managed by the network management system 300, e.g., the distributed antenna system 200.

[0076] According to an embodiment, the memory 310 may store the quality parameters of the synchronization source and the capacity parameters of the communication nodes connected to the synchronization source in various forms, for example, in a table form.

[0077] Referring to FIG. 4, the quality parameters and the capacity parameters are stored in the form of a table as shown in FIG. 4 according to an embodiment.

[0078] The table for storing quality parameters and capacity parameters includes information regarding the identification information of the communication node (e.g., DAS unit Name), the IP address of the communication node (e.g., DAS Unit IP Address), priority (e.g., Priority), whether the communication node can operate as a grand master (GM) of the IEEE 1588 PTP protocol (e.g., Designated 1588 GM Role), whether the communication node can operate as a source (or route) of syncE (e.g., SyncE source role), the maximum number of slave nodes that the communication node can accommodate (e.g., Max 1588 Slave Capacity), quality parameters of the synchronization source (e.g., Oscillator Quality), the number of slave nodes connected to the communication node currently operating as a grand master (e.g., Current 1588 Slave Counts), the activation state of the communication node (e.g., Unit State), and the synchronization mode in which the communication node is currently operating (e.g., Current 1588 Mode).

[0079] Depending on the embodiment, the quality parameter may include a quality parameter of the synchronization source (eg, Oscillator Quality) in the table of FIG.

[0080] Depending on the embodiment, the quality parameter may include, in the table of FIG. 4, information on whether the communication node can operate as a grand master (GM) of the IEEE 1588 PTP protocol (e.g., Designated 1588 GM Role), whether the communication node can operate as a syncE route (e.g., SyncE source role), the maximum number of slave nodes that the communication node can accommodate (e.g., Max 1588 Slave Capacity), the number of slave nodes connected to the communication node currently operating as a grand master (e.g., Current 1588 Slave Counts), the activation state of the communication node (e.g., Unit State), and the synchronization mode in which the communication node is currently operating (e.g., Current 1588 Mode).

[0081] Depending on the embodiment, in the table of FIG. 4, the priority may be a value calculated by the processor 320 using the quality parameter and the capacity parameter.

[0082] Depending on the embodiment, the priority may be determined by reflecting weights on each of the quality and capacity parameters.

[0083] The processor 320 may control the overall operation of the network management system 300 and may perform decisions and processes on the network management system 300 .

[0084] Depending on the embodiment, the processor 320 may determine the priority using quality and capacity parameters stored in the memory 310 .

[0085] The processor 320 selects a synchronization source to use for synchronizing the distributed antenna system 200 from among multiple synchronization sources (e.g., 500-1 to 500-3) within a communication network managed by the network management system 300, e.g., the distributed antenna system 200, based on the determined priority.

[0086] The communication interface 330 interfaces communications between the network management system 300 and the distributed antenna system 200 .

[0087] The clock policy handler 340 generates and outputs configuration signals for configuring communication nodes in a communication network, for example, the distributed antenna system 200.

[0088] Depending on the embodiment, the configuration signal may include information regarding the protocol to be used for synchronization in the communicating nodes (e.g., IEEE 1588 PTP, syncE, etc.), the synchronization mode to be used in the communicating nodes (e.g., transparent clock mode, boundary clock mode, master and slave configuration in boundary clock mode, etc.).

[0089] Depending on the embodiment, the clock policy handler 340 may transmit a configuration signal to the distributed antenna system 200 side via the communication interface 330 to configure a communication network, e.g., a communication node in the distributed antenna system 200, based on the result of the selection of the synchronization source by the processor 320.

[0090] According to an embodiment, the clock policy handler 340 may set a relatively close communication node as a master node and a relatively distant communication node as a slave node based on the communication nodes connected to the selected synchronization source, based on the result of the selection of the synchronization source by the processor 320.

[0091] Depending on the embodiment, the configuration signal may include a control signal for SyncE information configuration, IEEE 1588 PTP information configuration, etc. of the communication node.

[0092] Depending on the embodiment, the clock policy handler 340 may be embodied in the form of a partial function of the processor 320, in which case the clock policy handler 340 is provided in the processor 320.

[0093] Depending on the embodiment, the clock policy handler 340 may use the monitoring results of the clock source monitor 350 and the communication node monitor 360 to configure the communication node to use another synchronization source when a new synchronization source is attached or when a failure occurs in the synchronization source in use or in the communication node attached to the synchronization source.

[0094] The clock source monitor 350 monitors the status (e.g., quality status, operational status, fault status, addition or removal status of a synchronization source, etc.) of a synchronization source within a communications network, such as the distributed antenna system 200.

[0095] Depending on the embodiment, the clock source monitor 350 may store the monitoring results in a table stored in the memory 310 .

[0096] The communication node monitor 360 monitors the status of communication nodes in a communication network, for example, the distributed antenna system 200 (eg, the operational status, fault status, added or removed connection status of a communication node, etc.).

[0097] Depending on the embodiment, communication node monitor 360 may store the monitoring results reflected in a table stored in memory 310 .

[0098] 5, the monitoring results by the communication node monitor 360 are stored or updated in the form of a table shown in FIG.

[0099] The table shown in FIG. 5 includes characteristic information of communication nodes. The table for including characteristic information of the communication node may include identification information of the communication node (e.g., DAS unit Name), an IP address of the communication node (e.g., DAS Unit IP Address), whether or not the communication node supports IEEE 1588 PTP (e.g., 1588 support), whether or not the communication node supports syncE (e.g., syncE support), whether or not the boundary clock mode of the IEEE 1588 PTP protocol is supported (e.g., 1588 BC capability), whether or not the communication node supports a connection tracking function of the IEEE 1588 PTP protocol (e.g., 1588 connection tracking enable), the maximum number of slave nodes that can be accommodated in the communication node (e.g., Max 1588 Slave capacity), a synchronization mode of the IEEE 1588 PTP protocol currently being used in the communication node (e.g., Current 1588 Mode), the number of slave nodes tracked through the connection tracking function (e.g., current 1588 connection tracking counts), the number of slave nodes currently connected to the communication node (e.g., Current 1588 Slave capacity), and the number of slave nodes currently connected to the communication node (e.g., Current 1588 Slave capacity). The communication node status includes the following: Sync Counts, the activation state of the communication node (e.g., Unit State), and the slave-master interface state (e.g., Sync Slave Interface and Sync Master Interface).

[0100] Although FIG. 3 illustrates the configuration of a network management system 300, when the headend device 210 of the distributed antenna system 200 performs the communication network synchronization method according to an embodiment of the present invention, the headend device 210 can perform equivalent functions including the configurations 310 to 360 of FIG. 3.

[0101] 6 is a flow chart of a method for synchronizing a communication network according to an embodiment of the present invention, and FIG 7 is a diagram showing an example in which a synchronization mode of a communication node is set by the method for synchronizing a communication network of FIG 6.

[0102] Referring to FIG. 6, the network management system 300 or headend device 210 acquires quality parameters of at least two or more synchronization sources connected to communication nodes in a communication network (e.g., the distributed antenna system 200) and capacity parameters of the communication nodes connected to the synchronization sources (S610).

[0103] The network management system 300 or the headend device 210 determines a priority based on the acquired quality parameters and capacity parameters, and selects a synchronization source to be used for synchronizing the communication network (e.g., the distributed antenna system 200) according to the priority (S620).

[0104] The network management system 300 or the head end device 210 determines the synchronization mode of each communication node based on the synchronization source selected in step S620 (S630).

[0105] Depending on the embodiment, the synchronization mode may be divided into a transparent clock mode or a boundary clock mode, and a master and a slave in the boundary clock mode.

[0106] 7, in step S620, one synchronization source 500-1 of the plurality of synchronization sources 500-1 to 500-3 is selected as a synchronization source to be used for synchronizing a communication network (eg, the distributed antenna system 200).

[0107] In this case, the communication node 220-1 connected to the selected synchronization source 500-1 becomes a grand master (GM), and the synchronization mode of the remaining communication nodes is determined based on the communication node 220-1.

[0108] According to an embodiment, when determining the synchronization mode of the remaining communication nodes, the synchronization mode of the remaining communication nodes may be determined based on information about the communication node (e.g., 220-1) connected to the selected synchronization source and characteristic information of the remaining communication nodes 210, 220-2 to 220-4, 230-1, 230-2, 400 (whether or not they support boundary clock mode, the number of slave nodes that can be accommodated when the boundary clock mode is supported, etc.).

[0109] According to an embodiment, when the headend device 210 supports the boundary clock mode, the synchronization mode may be defined as shown in FIG.

[0110] According to an embodiment, the highest-level communication node (eg, 210) may be set to a boundary clock mode based on a communication node (eg, 220-1) connected to a selected synchronization source (eg, 500-1).

[0111] According to an embodiment, based on a selected synchronization source (eg, 500-1), the remaining communication nodes 230-1 and 230-2 except for the top communication node (eg, 210) and the end communication nodes 220-2 to 220-4 and 400 may be set in a transparent clock mode.

[0112] Returning to FIG. 6, a communications network, for example the distributed antenna system 200, synchronizes using a synchronization signal provided by a selected synchronization source (S640).

[0113] If a failure occurs in the selected synchronization source, the network management system 300 or the headend device 210 switches the synchronization source (e.g., 500-1) used to synchronize the communication network, e.g., the distributed antenna system 200, to another synchronization source (e.g., 500-2) (S650).

[0114] According to an embodiment, when switching the synchronization source to another synchronization source in step S650, one of the other synchronization sources (e.g., 500-2 and 500-3) may be selected based on the priority recalculated based on the quality parameter and the capacity parameter.

[0115] The network management system 300 or the headend device 210 monitors the fault status of the failed synchronization source or the communication node connected to the failed synchronization source, and determines whether to return to the original state to use the synchronization source that has been restored from the fault (i.e., the synchronization source selected before the failure occurred) (S660).

[0116] According to an embodiment, in step S660, when the failure of the failed synchronization source is recovered, if the difference between the quality of the recovered synchronization source (i.e., the synchronization source selected before the failure occurred) and the quality of the synchronization source currently in use exceeds a reference value, the network management system 300 or the headend device 210 may revert to the original state to use the recovered synchronization source.

[0117] Although the present invention has been described in detail with reference to preferred embodiments thereof, the present invention is not limited to the above embodiments and various modifications and alterations may be made by those skilled in the art within the technical spirit and scope of the present invention.

Claims

1. obtaining quality parameters of at least two or more synchronization sources coupled to a communication node in a communication network and capacity parameters of at least two or more communication nodes respectively coupled to said synchronization sources; selecting a synchronization source to be used for synchronizing the communication network from the at least two or more synchronization sources according to a priority order determined based on both quality parameters of the at least two or more acquired synchronization sources and capacity parameters of the at least two or more communication nodes; and synchronizing the communication network via a communication node coupled to the selected synchronization source using a synchronization signal provided by the selected synchronization source; The quality parameter is determined based on at least one of temperature stability, operating temperature range, hierarchical level, frequency quality, and phase quality; A method for synchronizing a communication network, wherein the capacity parameter is determined based on a maximum number of slave nodes that can be accommodated by the at least two communication nodes.

2. The quality parameters and the capacity parameters are The method of claim 1, wherein the synchronization information is stored in a table format in a network management system that manages the communication network.

3. The priority order is as follows: The method of claim 1 , wherein the synchronization is dynamically determined based on the quality parameter and the capacity parameter.

4. The method for synchronizing a communication network includes: The method of claim 1 , further comprising the step of receiving said capacity parameters from each of said at least two or more communication nodes in said communication network.

5. The priority order is as follows: The method of claim 1 , wherein the quality parameters and the capacity parameters are determined so as to reflect weights, respectively.

6. The method for synchronizing a communication network includes: After the step of selecting a synchronization source to be used for synchronizing the communication network, 2. The method for synchronizing a communication network according to claim 1, further comprising the step of determining a synchronization mode for each of the at least two or more communication nodes based on a selected synchronization source and characteristic information of each of the at least two or more communication nodes in the communication network.

7. The characteristic information of each of the at least two or more communication nodes is 7. The method of claim 6, further comprising at least one of: whether each of the at least two or more communication nodes supports a specific synchronization mode; whether the connected communication nodes can be tracked; the capacity of a slave node; the number of communication nodes currently connected to the communication node; and the number of slave nodes corresponding to the communication node.

8. The number of communication nodes currently connected to the communication node is 8. The method of claim 7, wherein the synchronization is achieved using the connectivity tracking function of the IEEE 1588 PTP protocol.

9. The synchronization mode is 7. The method of synchronizing a communication network according to claim 6, characterized in that the synchronization is performed in a transparent clock mode or a boundary clock mode of the IEEE 1588 PTP protocol.

10. The communication network includes: At least one of a headend device, an extension device, and a remote device; The method of claim 1, wherein at least one of the synchronization sources is coupled to the extension device or the remote device.

11. The method for synchronizing a communication network includes: monitoring the selected synchronization source for failure; 2. The method of claim 1, further comprising the step of: if the selected synchronization source fails, selecting another synchronization source for use in synchronizing the communication network according to a priority order recalculated based on the quality parameter and the capacity parameter.

12. The method for synchronizing a communication network includes:

12. The method for synchronizing a communication network according to claim 11, further comprising the step of: when a failure of a synchronization source in which a failure has occurred is restored, comparing a difference between a quality of the synchronization source selected before the occurrence of the failure and a quality of the other synchronization source, and determining which synchronization source to use for synchronizing the communication network.

13. a memory for acquiring and storing quality parameters of at least two or more synchronization sources coupled to communication nodes in a communication network and capacity parameters of at least two or more communication nodes respectively coupled to said synchronization sources; a processor for selecting a synchronization source to be used for synchronizing the communication network from the at least two or more synchronization sources according to a priority order determined based on both a quality parameter of the at least two or more synchronization sources and a capacity parameter of the at least two or more communication nodes; a communication interface for transmitting a setting signal to the communication network for synchronizing the communication network via a communication node connected to the selected synchronization source using a synchronization signal provided by the selected synchronization source; The quality parameter is determined based on at least one of temperature stability, operating temperature range, hierarchical level, frequency quality, and phase quality; A network management system, wherein the capacity parameter is determined based on a maximum number of slave nodes that the at least two communication nodes can accommodate.

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