Communication network synchronization method 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. More specifically, the present invention relates to a network management system and a method for synchronizing a communication network that can select a synchronization source used for synchronizing the communication network according to a priority based on quality parameters of the synchronization source and capacity parameters of communication nodes connected to the synchronization source.

Background Art

[0002] A currently commercially available distributed antenna system (DAS) has a form in which external reference clock information is received by a head-end device and the reference clock is transmitted to other nodes (for example, an extension device or a remote device).

[0003] However, since the head-end device is quite large in size and weight and requires a separate power supply, it is generally arranged in a separate space in a building where most distributed antenna systems are installed. In order to receive external reference clock information with such a structure, it is structurally inefficient in that a clock source and the head-end device arranged far apart must be connected by a cable.

Summary of the Invention

Problems 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 that can select a synchronization source used for synchronizing the communication network according to a priority based on quality parameters of the synchronization source and capacity parameters of communication nodes connected to the synchronization source.

Means for Solving the Problems

[0005] A method for synchronizing a communication network according to an embodiment of the present invention includes the steps of: obtaining quality parameters of at least two synchronization sources connected to a communication node in the communication network and capacity parameters of a communication node connected to the synchronization source; selecting a synchronization source to be used for synchronizing the communication network from the at least two synchronization sources based on a priority order derived from the obtained quality parameters and capacity parameters; and synchronizing the communication network using synchronization signals provided from the selected synchronization source.

[0006] In some embodiments, the quality parameters are determined based on at least one of the following: temperature stability, operating temperature range, hierarchy level, frequency quality, and phase quality.

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

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

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

[0010] In some embodiments, the quality parameters are determined based on at least one of the following: holdover time of the synchronization source, temperature stability, operating temperature range, hierarchy level, frequency quality, and phase quality.

[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 connected is operating as the master node.

[0012] In some embodiments, the method for synchronizing the communication network further includes the step of receiving the capacity parameters from each of the communication nodes in the communication network.

[0013] In some embodiments, the priority order is determined by reflecting weighted values ​​for the quality parameter and the capacity parameter, respectively.

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

[0015] In some embodiments, the characteristic information for each communication node includes at least one of the following: whether each communication node supports a specific synchronization mode, whether the connected communication nodes can be tracked, the capacity of the slave nodes, 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 the connection tracking function of the IEEE 1588 PTP protocol.

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

[0018] In some embodiments, the communication network comprises at least one of a headend device, an expansion device, and a remote device, and at least one of the synchronization sources is connected to the expansion 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 is failing, and, if the selected synchronization source fails, selecting another synchronization source to use for synchronizing the communication network based on a priority calculated again based on the quality parameter and the capacity parameter.

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

[0021] In some embodiments, if a failed synchronization source is restored, the further step includes comparing the quality difference between the synchronization source selected before the failure occurred and the quality of the other synchronization sources to determine 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 for acquiring and storing quality parameters and capacity parameters of at least two synchronization sources connected to a communication node in a communication network; a processor for selecting a synchronization source from the at least two synchronization sources to be used for synchronizing the communication network based on a priority order based on the quality parameters and capacity parameters; and a communication interface for transmitting a setting signal to the communication network for synchronizing the communication network using synchronization signals provided from the selected synchronization source. [Effects of the Invention]

[0023] The method and apparatus according to embodiments of the present invention can supply an optimal synchronization signal that matches the state of the synchronization source and the state of the communication network by selecting a synchronization source to be used for synchronizing the communication network based on a priority order based on the quality parameters of the synchronization source and the capacity parameters of the communication nodes connected to the synchronization source.

Brief Description of the Drawings

[0024] A brief description of each drawing is provided to better understand the drawings cited in the detailed description of the present invention. [Figure 1] It is a conceptual diagram of a communication system according to an embodiment of the present invention. [Figure 2] It is a block diagram according to an embodiment of the distributed antenna system shown in FIG. 1. [Figure 3] It is a block diagram according to an embodiment of the network management system shown in FIG. 1. [Figure 4] It is a table according to an embodiment showing parameters corresponding to each communication node connected to a synchronization source. [Figure 5] It is a table according to an embodiment showing characteristic information of each communication node. [Figure 6] It is a flowchart of a method for synchronizing a communication network according to an embodiment of the present invention. [Figure 7] It is a drawing showing an example in which the synchronization mode of a communication node is set by the method for synchronizing the communication network of FIG. 6.

Best Mode for Carrying Out the Invention

[0025] The technical idea of the present invention can be subjected to various modifications and can have various embodiments. Specific embodiments are illustrated in the drawings and will be described in detail below. However, this is not intended to limit the technical idea of the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, or alternatives included in the scope of the technical idea of the present invention.

[0026] In explaining the technical idea of the present invention, when it is determined that a specific description of such known technology will unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Also, the numbers (e.g., first, second, etc.) used in the description process of this specification are merely identification symbols for distinguishing one component from another.

[0027] Furthermore, in this specification, when one component is referred to as being "connected" or "linked" with another component, it should be understood that the component may be directly connected to or linked with the other component, but unless otherwise stated, it may also be connected or linked through other components in between.

[0028] Furthermore, terms such as "~part," "~device," "~child," and "~module" as used herein refer to a unit that processes at least one function or operation. This unit may be embodied in hardware or 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 that is combined with memory to store data necessary for processing at least one function or operation.

[0029] Furthermore, it should be made clear that the division of components in this specification is merely a division based on the main function that each component is responsible for. That is, two or more components described below may be combined into one component, or one component may be further divided into two or more components based on subdivided functions. It goes without saying that each component described below may also perform some or all of the functions that other components are responsible for, in addition to its own main function, and some of the main functions that each component is responsible for may be exclusively performed by other components.

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

[0031] Referring to Figure 1, the communication system 10 comprises a core network 50, a base transceiver station (BTS) 100, a distributed antenna system (DAS) 200 that relays communication signals from the base station 100, and a Network Management System (NMS) 300 that manages and monitors the distributed antenna system 200.

[0032] Depending on the embodiment, the communication system 10 is divided into a core network 50, a base station 100 that constitutes 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 described as an example of a communication 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 can form a single communication network with the network management system 300.

[0035] The distributed antenna system 200 comprises a headend device 210 which is communicatively connected to the base station 100 and constitutes a headend node; a plurality of remote devices 220a, 220b, 220c, and 220d which constitute remote nodes and are connected to other remote nodes, or which are located at the respective remote service locations and are communicatively connected to user terminals; and expansion devices 230a and 230b which constitute expansion nodes.

[0036] Depending on the embodiment, the distributed antenna system 200 is embodied as an analog distributed antenna system.

[0037] In other embodiments, the distributed antenna system 200 may be embodied as a digital distributed antenna system, which may optionally be a mixed type (for example, in which some nodes perform analog processing and the remaining nodes perform digital processing).

[0038] On the other hand, Figure 1 shows an example of the topology of the distributed antenna system 200, and the distributed antenna system 200 can be modified in various ways in light of the specific characteristics of the installation area and application field (for example, inside buildings, subways, hospitals, stadiums, etc.).

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

[0040] To describe in more detail each node and its function within the distributed antenna system 200, the headend device 210 acts as an interface with the base station.

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

[0042] Depending on the embodiment, the headend device 210 may be embodied in a main headend device and a sub-headend device, connected to base stations of a specific operator by service frequency band or by each sector, and the main headend device may optionally have its coverage supplemented by the sub-headend device.

[0043] Generally, the RF (Radio Frequency) signals transmitted from base stations are high-power signals. Therefore, the headend device 210 attenuates these high-power RF signals to signals of a power suitable for processing at each node. The headend device 210 reduces the high-power RF signals to low power for each frequency band or each sector. The headend device 210 combines the low-power RF signals and distributes the combined signals to the expansion device 230a or remote device 220a.

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

[0045] Each of the remote devices 220a, 220b, 220c, and 220d separates the transmitted and combined signals by frequency band and performs signal processing such as amplification. Through this process, each of the remote devices 220a, 220b, 220c, and 220d transmits the base station signal to user terminals within its service coverage via a service antenna (not shown).

[0046] Remote devices 220a and 220b are connected via an RF cable or wireless communication, and multiple remote devices can be connected in a cascaded configuration as needed.

[0047] The expansion device 230a transmits the transmitted and combined signals to the remote device 220c, which is connected to the expansion device 230a.

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

[0049] On the other hand, the base station 100 and the headend device 210 are connected to each other via RF cables, optical cables, or Ethernet cables (e.g., twisted cables, UTP cables), and at the lower end of the headend device 210, except between remote devices 220a and 220b, they are connected to each other via optical cables or Ethernet cables (e.g., twisted cables, UTP cables), and the signal transmission medium and communication method between each node can be varied in many ways.

[0050] Depending on the embodiment, if 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 expansion devices 230a and 230b may include optical transceiver modules for transmitting and receiving optical type signals via electro-to-optical / photoelectric conversion, and may also include WDM (Wavelength Division Multiplexing) elements if the nodes are connected by a single optical cable.

[0051] Such a distributed antenna system 200 is connected via a network to an external management device (not shown), such as an NMS (Network Management System) 300 or an NOC (Network Operation Center) (not shown). This allows the 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 Figure 1, for the sake of clarity, the synchronization source connected to the communication node has been omitted.

[0053] Figure 2 is a block diagram of one embodiment of the distributed antenna system shown in Figure 1.

[0054] Referring to both Figures 1 and 2, the distributed antenna system 200A comprises a headend unit 210, remote units 220-1 to 220-4, expansion units 230-1 and 230-2, a smolcell 400, and synchronization sources 500-1 to 500-3.

[0055] As an example of a communication network, the distributed antenna system 200A comprises multiple communication nodes (for example, a headend device 210, remote devices 220-1 to 220-4, and expansion devices 230-1 and 230-2).

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

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

[0058] Depending on the embodiment, the network management system 300 or headend device 210 obtains 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 determines the priority of the synchronization sources (e.g., 500-1 to 500-3) based on the obtained quality parameters and capacity parameters.

[0059] Quality parameters refer to a variety of parameters that indicate the accuracy and stability of the synchronization signal provided by the synchronization source.

[0060] For example, quality parameters are determined based on at least one of the following: holdover time of the synchronization source, temperature stability, operating temperature range, hierarchy level, frequency quality, and phase quality.

[0061] For example, frequency quality can be a quality indicator that shows the number of signals with frequency errors (e.g., 16 ppb) out of a reference number of signals.

[0062] For example, phase quality is a quality indicator (e.g., + / - 5 ns) that shows the time range in which phase errors occur.

[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 is acting as the master node.

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

[0065] Examples of quality parameters and capacity parameters will be discussed later, referring to both Figure 4.

[0066] Depending on the embodiment, the priority is determined fluidly based on varying quality and capacity parameters.

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

[0068] Synchronization sources 500-1 or 500-3 generate the synchronization signal.

[0069] Depending on the embodiment, the synchronization sources 500-1 to 500-3 may include GPS (Global Positioning System) antennas, in which 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 Primary Reference Clock (PRC) or Primary Reference Source (PRS) from Stratum 1, a Synchronization Supply Unit (SSU), Stand-Alone Synchronization Equipment (SASE), or Building Integrated Timing Supply (BITS) from Stratum 2, or an SDH Equipment Clock (SEC) from Stratum 3.

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

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

[0073] Referring to Figures 1 to 3, the network management system 300 comprises 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] Memory 310 stores the data necessary for the operation of the network management system 300.

[0075] Depending on the embodiment, the memory 310 may store data necessary to select 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, such as the distributed antenna system 200.

[0076] Depending on the embodiment, the memory 310 may store the quality parameters of the synchronization source and the capacity parameters of the communication node connected to the synchronization source in various forms, for example, in a table format.

[0077] Referring to Figure 4, the quality parameters and capacity parameters are stored in the table format shown in Figure 4 depending on the embodiment.

[0078] The tables for storing quality and capacity parameters include information about the communication node's identification information (e.g., DAS unit name), the communication node's IP address (e.g., DAS Unit IP Address), priority (e.g., Priority), whether the communication node can operate as a grandmaster (GM) of the IEEE 1588 PTP protocol (e.g., Designated 1588 GM Role), whether it can operate as a syncE source (or root) (e.g., SyncE source role), the maximum number of slave nodes the communication node can accommodate (e.g., Max 1588 Slave Capacity), the quality parameters of the synchronization source (e.g., Oscillator Quality), the number of slave nodes currently connected to the communication node acting as a grandmaster (e.g., Current 1588 Slave Counts), the activation state of the communication node (e.g., Unit State), and the synchronization mode the communication node is currently operating in (e.g., Current 1588 Mode).

[0079] Depending on the embodiment, the quality parity meter may include the quality parameters of the synchronization source (e.g., Oscillator Quality) in the table in Figure 4.

[0080] Depending on the embodiment, the quality parity meter may include information in the table of Figure 4 regarding whether the communication node can operate as a grandmaster (GM) of the IEEE 1588 PTP protocol (e.g., Designated 1588 GM Role), whether it can operate as a syncE source role (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 currently connected to the communication node operating as a grandmaster (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 Figure 4, the priority may be a value calculated by the processor 320 using quality parameters and capacity parameters.

[0082] Depending on the embodiment, the priority may be determined by reflecting weighted values ​​for the quality parameter and the capacity parameter, respectively.

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

[0084] Depending on the embodiment, the processor 320 may determine priority using quality parameters 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 the communication network managed by the network management system 300, for example, the distributed antenna system 200, based on the determined priority.

[0086] The communication interface 330 interfaces communication 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, such as a distributed antenna system 200.

[0088] Depending on the embodiment, the configuration signal may include information about the protocol used for synchronization at the communication node (e.g., IEEE 1588 PTP, syncE, etc.) and information about the synchronization mode used at the communication node (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 for configuring communication nodes in the communication network, for example, the distributed antenna system 200, based on the result of the processor 320's selection of a synchronization source.

[0090] Depending on the embodiment, the clock policy handler 340 may, based on the result of the processor 320's selection of a synchronization source, set the communication node that is relatively close to the selected synchronization source as the master node and the communication node that is relatively far as the slave node.

[0091] Depending on the embodiment, the setting signal may include control signals for setting SyncE information, IEEE 1588 PTP information, and the like for a communication node.

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

[0093] In some embodiments, 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 nodes to use another synchronization source when a new synchronization source is connected, or when a synchronization source currently in use or a communication node connected to the synchronization source fails.

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

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

[0096] The communication node monitor 360 monitors the status of communication nodes within a communication network, such as a distributed antenna system 200 (e.g., operational status of communication nodes, fault status, status of adding or removing communication nodes, etc.).

[0097] Depending on the embodiment, the communication node monitor 360 may reflect the monitoring results in a table stored in memory 310 and save them.

[0098] Referring to Figure 5, the monitoring results from the communication node monitor 360 are saved or updated in the table format shown in Figure 5.

[0099] The table shown in Figure 5 contains characteristic information of the communication node. The table containing the characteristics information of the communication node includes the communication node's identification information (e.g., DAS unit Name), the communication node's IP address (e.g., DAS Unit IP Address), whether it supports IEEE 1588 PTP (e.g., 1588 support), whether it supports syncE (e.g., syncE support), whether it supports the boundary clock mode of the IEEE 1588 PTP protocol (e.g., 1588 BC capability), whether it supports the connection tracking function of the IEEE 1588 PTP protocol (e.g., 1588 connection tracking enable), the maximum number of slave nodes that the communication node can accommodate (e.g., Max 1588 Slavecapacity), the synchronization mode of the IEEE 1588 PTP protocol currently used by 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), and the number of slave nodes currently connected to the communication node (e.g., Current 1588 Slave This includes the Counts, the activation state of the communication node (e.g., Unit State), and the slave / master interface states (e.g., Sync Slave Interface and Sync Master Interface).

[0100] Figure 3 illustrates the configuration of the 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 the same functions including the configurations 310 to 360 in Figure 3.

[0101] Figure 6 is a flowchart of a communication network synchronization method according to one embodiment of the present invention. Figure 7 is a diagram showing an example in which the synchronization mode of a communication node is set by the communication network synchronization method of Figure 6.

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

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

[0104] The network management system 300 or headend device 210 determines the synchronization mode for 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 transparent clock mode or boundary clock mode, and master and slave in boundary clock mode.

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

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

[0108] Depending on the 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 connected to the selected synchronization source (e.g., 220-1) and characteristic information of the remaining communication nodes 210, 220-2 to 220-4, 230-1, 230-2, and 400 (such as whether boundary clock mode is supported and the number of slave nodes that can be accommodated when boundary clock mode is supported).

[0109] Depending on the embodiment, if the headend device 210 supports the boundary clock mode, the synchronization mode may be defined in the form shown in Figure 7.

[0110] Depending on the embodiment, the top-level communication node (e.g., 210) may be set to boundary clock mode with respect to a communication node (e.g., 220-1) connected to a selected synchronization source (e.g., 500-1).

[0111] Depending on the embodiment, with respect to a selected synchronization source (e.g., 500-1), the top-level communication node (e.g., 210) and terminal communication nodes 220-2 to 220-4, excluding 400, may be set to transparent clock mode, while the remaining communication nodes 230-1 and 230-2 may be set to transparent clock mode.

[0112] Returning to Figure 6, the communication network, for example, the distributed antenna system 200, performs synchronization using the synchronization signal provided from the selected synchronization source (S640).

[0113] The network management system 300 or headend device 210 switches the synchronization source used to synchronize the communication network, for example, the distributed antenna system 200 (e.g., 500-1) to another synchronization source (e.g., 500-2) if the selected synchronization source fails (S650).

[0114] In some embodiments, when switching from one synchronization source to another in step S650, one of the other synchronization sources (e.g., 500-2 and 500-3) may be selected based on a priority order recalculated based on the quality and capacity parameters.

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

[0116] Depending on the embodiment, in step S660, the network management system 300 or headend device 210 may, if the failure of the failed synchronization source is recovered, revert to its original state to use the recovered synchronization source 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 currently used synchronization source exceeds a threshold value.

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

Claims

1. The steps include obtaining quality parameters of at least two synchronization sources connected to a communication node in a communication network, and capacity parameters of at least two communication nodes each connected to the synchronization source, A step of selecting a synchronization source to be used for synchronizing the communication network from the at least two synchronization sources based on a priority determined based on both the quality parameters of the at least two synchronization sources obtained and the capacity parameters of the at least two communication nodes, A step of determining the synchronization mode for each of the at least two communication nodes based on the selected synchronization source and the characteristic information of each of the at least two communication nodes in the communication network, The process includes the step of synchronizing a communication network via a communication node connected to the selected synchronization source, using a synchronization signal provided from the selected synchronization source, in a defined synchronization mode, The aforementioned quality parameters are determined based on at least one of the following: temperature stability, operating temperature range, hierarchy level, frequency quality, and phase quality. A method for synchronizing a communication network, wherein the capacity parameter is determined based on the maximum number of slave nodes that can be accommodated by the at least two communication nodes.

2. The aforementioned quality parameter and the aforementioned capacity parameter are, The method for synchronizing a communication network according to claim 1, wherein the data is stored in a table format in a network management system that manages the aforementioned communication network.

3. The aforementioned priority order is, A method for synchronizing a communication network according to claim 1, wherein the parameters are determined flexibly based on the quality parameters and capacity parameters.

4. The method for synchronizing the aforementioned communication network is: The method for synchronizing a communication network according to claim 1, further comprising the step of receiving the capacity parameter from each of the at least two communication nodes in the communication network.

5. The aforementioned priority order is, A method for synchronizing a communication network according to claim 1, wherein the quality parameter and the capacity parameter are determined by reflecting weighted values.

6. The characteristic information of each of the at least two communication nodes is as follows: A method for synchronizing a communication network according to claim 1, comprising at least one of the following: whether each of the two or more communication nodes supports a specific synchronization mode; whether the connected communication nodes can be tracked; the number of communication nodes currently connected to the communication node; and the number of slave nodes currently connected to the communication node.

7. The number of communication nodes currently connected to the aforementioned communication node is: A method for synchronizing a communication network according to claim 6, which is achieved using the concatenation tracking function of the IEEE 1588 PTP protocol.

8. The aforementioned synchronization mode is A method for synchronizing a communication network according to claim 1, wherein the IEEE 1588 PTP protocol is in transparent clock mode or boundary clock mode.

9. The aforementioned communication network is It comprises at least one of a headend device, an expansion device, and a remote device, The method for synchronizing a communication network according to claim 1, wherein at least one of the synchronization sources is connected to the expansion device or the remote device.

10. The method for synchronizing the aforementioned communication network is: A step of monitoring whether the selected synchronization source is faulty, A method for synchronizing a communication network according to claim 1, further comprising the step of selecting another synchronization source to use for synchronizing the communication network if the selected synchronization source fails, based on a priority calculated again on the quality parameter and the capacity parameter.

11. The method for synchronizing the aforementioned communication network is: The method for synchronizing a communication network according to claim 10, further comprising the step of, when the failure of a synchronization source has been resolved, comparing the difference in quality between 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.

12. A memory that acquires and stores quality parameters of at least two synchronization sources connected to a communication node in a communication network, and capacity parameters of at least two communication nodes each connected to the synchronization source, A processor that selects a synchronization source to be used for synchronizing the communication network from the at least two synchronization sources based on a priority determined based on both the quality parameters of the at least two synchronization sources and the capacity parameters of the at least two communication nodes, and determines the synchronization mode for each of the at least two communication nodes based on the selected synchronization source and the characteristic information of each of the at least two communication nodes in the communication network, A communication interface that transmits a configuration 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 from the selected synchronization source and according to a defined synchronization mode, The aforementioned quality parameters are determined based on at least one of the following: temperature stability, operating temperature range, hierarchy level, frequency quality, and phase quality. A network management system in which the capacity parameter is determined based on the maximum number of slave nodes that can accommodate the at least two communication nodes.

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