KR102271243B1 - Data collecting method using low-power wireless communication and lnker-gateway system - Google Patents

Abstract

A linker-gateway system of the present invention is a system for collecting data generated by one or more devices by using low power wireless communication. The system comprises: a linker which receives data generated from the devices and transmits it through low power wireless communication; and a gateway that performs data communication with a server-side terminal and receives the data from the linker through the low power wireless communication. When the linker and the gateway perform communication by obtaining a communication resource in units of time slots through allocation, communication can be performed by dividing, in advance, a periodic section for forming a communication channel defined in advance on a regular basis and an on-demand section for forming a communication channel by negotiation during every occurrence.

Description

Data collection method using low-power wireless communication and linker-gateway system for performing the same {DATA COLLECTING METHOD USING LOW-POWER WIRELESS COMMUNICATION AND LNKER-GATEWAY SYSTEM}

The present invention relates to a resource allocation and scheduling method in a machine type communication environment based on low power wireless communication, and to a data collection method using low power wireless communication and a linker-gateway system for performing the same.

The Internet accommodates various services and requires a large bandwidth, that is, a high-speed communication environment due to the environmental characteristics used by unspecified people, whereas the machine-type Internet of Things environment called the Internet of Things environment does not have bandwidth. It is characterized by providing an environment in which a plurality of terminals can communicate stably with each other.

As a representative system of the machine type environment in the field of power grid management, an automation system that remotely monitors facilities and periodically collects various information can be mentioned, and specifically, there are distribution automation and remote meter reading systems. In the case of distribution automation, the collected information is divided into periodic status information and event information to inform the situation such as the occurrence of an accident.

Here, the state information of the periodicity is a value indicating the state of open, closed, locked, unlocked, etc. to check the phase current, the surrounding state of the facility (Binary Input), and the current and voltage state values for measuring the power quality (Analog Input) , a value to control (Binary Output), a value indicating the number of times of a certain state such as the number of operation times of the device, the number of FI experiences (Counter), and a continuous value to set the state of the minimum operating current, parameter setting, curve setting, etc. It is divided into a sending value (Analog Output), and the amount of information to be transmitted is fixed according to the characteristics of each information, and furthermore, the information is transmitted in a form of transmitting information at a certain period.

In the case of linking periodicity information generated in the field with a wireless communication network, time resources (eg, time slots) are allocated when information is to be transmitted, and the information is transmitted at the allocated time. This is called the On Demand method, and in the case of a mobile communication network such as LTE, high-speed communication is possible, so it can be operated without major problems. However, in a narrow-band low-speed communication environment such as LPWA (Low Power Wide Area), which is being actively discussed recently, There are performance limitations to use the real-time On Demand environment.

In other words, when a channel (resource) allocation request, allocation result notification, and confirmation are performed in an environment where it takes a lot of time to send the information generated by the device, an additional delay occurs in addition to the actual data transmission time to be sent. It may cause problems such as service quality degradation, such as the inability to provide services in , and restrictions on the number of terminals that can be accommodated.

In addition, even though the sending time is fixed, it is necessary to perform an unnecessary resource allocation process (protocol) at the same time every time. In particular, from the standpoint of a terminal requiring a low-power environment, power consumption increases due to an increase in the number of communications. can In view of the need to provide stable services, a solution is needed.

Republic of Korea Publication No. 10-2019-0037832

An object of the present invention is to propose a data collection method and/or linker-gateway system using low-power wireless communication capable of allocating efficient communication resources in a power grid management system built in a low-power communication environment such as the Internet of Things.

A linker-gateway system according to an aspect of the present invention is a system for collecting data generated by one or more devices using low-power wireless communication,

a linker that receives data generated from the device and transmits it through low-power wireless communication; and a gateway that performs data communication with a server-side terminal and receives data from the linker through low-power wireless communication,

When the linker and the gateway perform communication by receiving communication resources allocated in units of time slots, a periodical interval for forming a communication channel defined in advance on a regular basis and an on-demand interval for forming a communication channel by negotiating each time it occurs Communication can be performed by classifying in advance.

Here, the server-side terminal and the gateway perform Ethernet-based communication, the gateway and the linker perform communication based on a DLMS protocol, and the linker and the device may perform RS232/485 serial communication.

Here, in the periodical section, as each periodic communication section, the synchronization securing channel (CCH) is operated only at the time point of each section regardless of the length of the periodic section, and the data transmission channel (SCH) can be operated in the remaining sections. .

Here, in the on-demand section, the synchronization securing channel (CCH) is operated only at the time of each section, and the data transmission channel (SCH) is operated in the remaining sections, but the length of the data transmission channel following the synchronization securing channel is described can do.

Here, the gateway may include a resource management table in which characteristics of data generated by each device are described with respect to the one or more devices.

Here, when the linker logs in, the gateway may search for data characteristics of a device connected to the linker from the resource management table, and allocate the periodic communication interval according to the retrieved data characteristics.

Here, the linker may include a storage module for temporarily storing the data received from the device before transmitting it to the gateway.

Here, characteristics of data to be transmitted from the connected device are recorded in the storage module, and when the linker receives a request for data transmission of the device from the gateway, it allocates communication resources to the gateway according to the characteristics of the recorded data. Simultaneously with the request, it is possible to instruct the device to transmit data.

A data collection method using low-power wireless communication according to another aspect of the present invention includes: a linker that receives data generated from one or more devices and transmits it through low-power wireless communication; and a method of collecting data generated by the devices by using a gateway that performs data communication with a server-side terminal and receives data from the linker through low-power wireless communication,

setting a periodical section as a periodic communication section and an on-demand section as an aperiodic communication section; buffering data generated from the device; forming a communication channel as prescribed in the periodical section, and forming a communication channel through negotiation between the linker and the gateway in the on-demand section; It may include transmitting buffered data from the linker to the gateway through the established communication channel.

Here, in the periodical period, the synchronization securing channel (CCH) may be operated only at the time point of each period irrespective of the length of each periodical period, and the data transmission channel (SCH) may be operated in the remaining periods.

Here, in the on-demand section, the synchronization securing channel (CCH) is operated only at the time of each section, and the data transmission channel (SCH) is operated in the remaining sections, but the length of the data transmission channel following the synchronization securing channel is described can do.

Here, in the setting of the communication interval, a periodic communication interval and an aperiodic communication interval may be allocated according to characteristics of data generated by the device.

Here, the setting of the communication section may be performed when the linker accesses the gateway.

Here, in the step of setting the period and on-demand period, the data characteristic of the device connected to the linker may be searched from the resource management table held by the gateway, and the periodic interval may be allocated according to the retrieved data characteristic. .

Here, the step of forming the communication channel may include: determining whether a time point at which the communication channel is to be formed is between a periodic section and an on-demand section; checking a pre-allocated communication resource if the period is a period; performing, by the linker and the gateway, negotiation for communication resource allocation in the on-demand section; and forming a wireless communication channel between the linker and the gateway using the allocated communication resource.

Here, when the amount of data transmitted from the device is large and it takes a considerable amount of time to transmit, the step of buffering the data may be performed in parallel with the step of the linker and the gateway negotiating communication resource allocation.

A gateway according to another aspect of the present invention is a gateway that collects data generated by one or more devices using low-power wireless communication and transmits it to a server-side terminal,

a communication layer module having physical layers and lower layers for performing data communication with the devices and the server-side terminal; a resource management unit for managing communication resources in a low-power wireless communication environment; and an application module including service applications for performing individual power-related services, wherein the resource management unit is connected to a Packet Analyzer for analyzing device-side packets, and Policy&Scheduler for performing resource allocation and scheduling for each device A resource management table for storing communication resource management information for devices may be provided.

When the data collection method and/or linker-gateway system using the low-power wireless communication of the present invention according to the above-described configuration is implemented, there is an advantage in that real-time data acquisition can be improved in a low-power wireless communication environment.

The data collection method and/or linker-gateway system of the present invention has the advantage of optimizing communication resource use and increasing service capacity by proposing a resource allocation method for each service in a low-power wireless communication environment.

The data collection method and/or linker-gateway system of the present invention classifies the service characteristics of the presented devices (Things) and allocates them in advance using a scheduling technique to reserve/use data resources in advance, thereby minimizing unnecessary resources. There are advantages of improving resource efficiency and minimizing transmission time.

In the data collection method and/or linker-gateway system of the present invention, the device recognizes this in advance, divides the Sleep and Non-Sleep sections, operates the device only during the allocated time, and sleeps at other times. There is an advantage of reducing power consumption.

The data collection method and/or linker-gateway system of the present invention has the advantage of greatly increasing the reliability of the construction system.

The data collection method and/or linker-gateway system of the present invention has the advantage of reducing construction and maintenance costs of devices as it can stably accommodate a large-scale device in a narrowband environment.

1 is a conceptual diagram illustrating an information transmission structure using a device of a wireless communication method in an automation system for power equipment such as a distribution automation system.
FIG. 2 is a transaction flow diagram illustrating a channel allocation process when a general communication channel allocation method is applied to the data transmission structure of FIG. 1;
3 is a system configuration diagram showing a linker-gateway system according to the spirit of the present invention.
4 is a data frame configuration diagram illustrating a channel allocation and data transmission process at a device end;
5 is a data frame configuration diagram illustrating a channel structure for a case in which periodic resource allocation is desired.
6 is a data frame configuration diagram illustrating an operational structure (odd OnDemand/even periodic) according to service characteristics.
7 is a data frame configuration diagram illustrating a channel assignment and data transmission process at a gateway.
8 is a transaction flow diagram illustrating a device service registration procedure.
9 is a block diagram showing the detailed configuration of a gateway and a linker according to the spirit of the present invention.
10 is a flowchart illustrating a data collection method using low-power wireless communication according to the spirit of the present invention.
11 is a transaction flow diagram illustrating a DLMS (Device Language Message Specification) remote meter reading data collection process.
12 is a data frame configuration diagram illustrating a DLMS packet structure;
13 is a bit table illustrating a structure of Control field bits of a DLMS;
14 is a packet conceptual diagram illustrating the configuration of a DLMS service packet;
15 is a data frame configuration diagram illustrating a resource allocation scheme of periodic data;
16 is a data frame configuration diagram showing a DNP interface of distribution automation.
17 is a packet conceptual diagram illustrating a distribution automation service flow (Request - Response).
18 is a transaction flow diagram illustrating a distribution automation operation flow using the proposed method according to the spirit of the present invention.

In describing the present invention, terms such as first, second, etc. may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it can be understood that other components may exist in between. .

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression may include the plural expression unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or numbers, It may be understood that the existence or addition of steps, operations, components, parts or combinations thereof is not precluded in advance.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

1 is a diagram illustrating an information transmission structure using a device of a wireless communication method in an automation system for power equipment such as a distribution automation system, and is intended to be detailed as a distribution automation system.

As shown in FIG. 1, based on the distribution automation operating system, a device (FRTU) is installed on a substation at the site, and it is configured and operated as a system that periodically acquires site information. At this time, the communication network uses wireless technology for wire-based optical communication composed of COT (Center Office Terminal)-RT (Remote Terminal) and for the section where adjacent optical lines are not installed, and configures the communication network between adjacent devices and provides service. is expanding

For example, in the illustrated configuration, the wireless modem and the wireless modem may use a 380 MHz band narrowband network for reliability, stability, and security of the power control network.

In automation systems such as distribution automation, real-time data is very important, but since data is exchanged between RT and wireless modem and between wireless modem and device by 9.6kbps serial communication, it can be used not only in the narrowband wireless communication section but also in the serial communication section. Latency also acts as a factor that greatly affects system performance.

FIG. 2 illustrates a channel allocation process when a general communication channel allocation method is applied to the data transmission structure of FIG. 1 .

For example, when requesting measurement information as shown in FIG. 2 , the RT terminal transmits a request packet of 50 bytes to the device terminal, and the device transmits a response packet of 280 bytes to the RT in response. In this case, if you look at the transmission time for each section, section A (50ms, transmission delay according to serial communication section), section B (50ms, channel assignment), section C (50ms, data transmission), section D (50ms, serial Transmission delay according to communication section), E section (270ms, transmission delay according to serial communication section), F section (200ms ~ 1,000ms, channel assignment), G section (100ms, data transmission), H section (270ms, serial communication) Transmission delay depending on the section) takes a total of 1,040ms to 1,840ms.

In particular, a delay of 640 ms occurs in the serial communication section, which occupies a relatively large proportion compared to the air interface section. As a result, suitability in the distribution automation system that values real-time performance is reduced.

FIG. 3 shows the configuration of a linker-gateway system according to an embodiment of the present invention for improving real-time information collection in a low-power wireless communication environment according to the spirit of the present invention.

The illustrated linker-gateway system has a form in which various devices are connected to the gateway 300 through the linker 200 and the gateway 300 is connected to the platform 400 (AS).

When various information of a physical space is measured using a plurality of devices, the gateway 300 collects this information and delivers it to the platform 400 (ie, the server side of the corresponding service). A user or manager of the corresponding service may inquire information on the gateway 300 or devices through the platform 400 , and may control the gateway 300 and devices in some cases.

In general, the platform 400 and the gateway 300 are supplied with voltage through a wire, whereas the device is operated based on a battery according to an installation situation. In the case of the linker 200, it is operated based on a battery or wired power supply depending on the installation situation. Depending on the implementation, the communication connection between the platform 400 and the gateway 300 and between the device and the linker 200 may be wired or wireless. However, the gateway 300 and the linker 300 use low-power wireless communication according to the spirit of the present invention. In particular, due to the nature of the machine type environment, devices operate with low power and communicate with the gateway 300 using a communication technology with a very small communication bandwidth.

The illustrated linker-gateway system is a kind of communication linkage device that collects data generated by one or more devices using low-power wireless communication.

The illustrated linker-gateway system includes a linker 200 as a sensor-side wireless modem unit that receives data generated from the device and transmits it through low-power wireless communication; and a gateway 300 as a server-side wireless modem unit that performs data communication with a server-side (remote) terminal and receives data through low-power wireless communication from the first wireless modem unit, wherein the linker (first wireless modem) unit) and the gateway (second wireless modem unit), when performing communication by receiving communication resources allocated in units of time slots, periodically negotiate a periodical (periodic communication) section that forms a predefined communication channel, and negotiation every time it occurs Thus, the on-demand (aperiodic communication) section forming the communication channel is divided and performed in advance.

In order to perform communication between the gateway 300 and the device, a communication resource is requested, the communication resource is allocated according to the requested information, and data is transmitted to the allocated communication resource. In order to perform these functions, it is proposed to classify the characteristics of the service and data to be delivered, and to effectively allocate resources, connect and manage sessions based on this. To this end, the linker 200, which is a device-side communication module, defines a Clink Network Layer (CNL), and the gateway 300 that is a server-side communication module defines Clink Network Management (CNM). The information generated through the above process is transmitted/received through Clink.

Hereinafter, a case in which the link and the gateway perform low-power wireless communication based on the DLMS method according to the spirit of the present invention will be described in detail.

The minimum unit of communication resource is defined as a Cell, and the Cell can be composed of a channel (CCH) for securing synchronization according to information to be transmitted and a channel (SCH) for transmitting data. Here, in the CCH channel, terminal ID information and allocated resource block location information are defined, and the SCH channel is combined into a plurality of cells according to the amount of information to be transmitted. In general, one CCH channel and four SCH channels are configured, and this is configured as one slot. In order to solve the delay problem in the resource (resource) allocation process between uplink and downlink channels, two slots can be bundled to form a subframe and can be operated.

4 shows a subframe used in the channel allocation and data transmission process when the initial device-side linker connects to the gateway. The illustrated process may occur at the time of the on-demand (aperiodic communication) section in the case of the present invention.

As shown in the figure, when on-demand type data transmission is required, the device-side linker 200 requests a device resource (communication resource) to the gateway 300 using a CCH channel, and the gateway sends the request information. Based on the CCH channel, the SCH resource is allocated to the device-side linker 200 through the CCH channel, and the allocated resource block information is transmitted to the CCH channel. The device-side linker 200 transmits usage information on the SCH channel in a designated resource time zone through the CCH channel. When data is normally received, the gateway 300 sends a confirmation message whether it has been normally received through the existing CCH channel. The size of a packet to be transmitted may be different depending on the service, and in this case, the size of the allocated channel may be adjusted according to the size.

As pointed out above as a problem, unlike the high-speed mobile communication system, in a narrowband environment, in order to operate a plurality of terminals in an on-demand form, resources must be allocated using the CCH channel at every moment, and in this case, from the viewpoint of utilization efficiency In this case, a loss of up to 20% will occur.

5 is a data frame configuration diagram illustrating a channel structure for resource allocation according to the spirit of the present invention when periodic communication is desired.

6 is a data frame configuration diagram illustrating an operation structure according to service characteristics (odd OnDemand/even periodic).

In order to compensate for the above-described performance degradation problem, as shown in FIG. 5, a slot composed of an existing CCH channel and an SCH channel is configured only with an SCH channel except for the CCH channel. A dedicated slot for transmitting periodic information. can be configured as In this case, since the function of the CCH channel is lost from the viewpoint of the terminal, the uplink transmission efficiency can be greatly improved.

The On Demand and Periodic structure configures the frame structure in consideration of the number of devices connected to the gateway 300, the channel usage environment, periodic data characteristics to be sent from the terminal, the amount of information, etc. can operate For example, in the case of a service requiring real-time performance, it can be implemented in the form of On Demand slot / Periodic Slot / On Demand slot ... as shown in FIG. 6, and in terms of enhancing implementation convenience, as shown in FIG. 5, 5 On Demand slots - It is possible to design a frame structure in the form of 5 periodic slots. The frame structure defined in this way may deliver the structure information to the device-side linker 200 through the CCH channel.

According to the above-described structure information, when the linker 200 and the gateway 300 are allocated resources (communication resources) in units of time slots to perform communication, periodical (periodic) forming a communication channel defined in advance on a regular basis. communication) section and an on-demand (aperiodic communication) section that forms a communication channel by negotiating each time it occurs, and performing it in advance.

7 is a data frame configuration diagram illustrating a channel assignment and data transmission process at the gateway end.

8 is a transaction flow diagram illustrating a device service registration procedure.

9 is a block diagram illustrating a detailed configuration of a gateway and a linker according to the spirit of the present invention.

First, according to the above-described service, the CNM determines periodic data and aperiodic data and performs scheduling to allocate resources accordingly. When scheduling is determined, it is allocated to the terminal for each channel, which will be described with reference to FIGS. 7 to 9 as follows.

In a periodic environment, a resource block location that can be used for the device is designated when the device-side linker 200 accesses the gateway 300 . To this end, when the device/linker 200 is installed in the field and power is applied, the device type and transmitted characteristics can be transmitted when initially connecting to the gateway and registering the device. Based on this, resource block allocation is performed, and for this purpose, the gateway (specifically, the resource management unit) may operate the following resource management table 346 .

The resource management table 346 includes a terminal ID and an address (source, destination), and defines a service ID, a standard ID, and a repetition period to identify the characteristics of periodic data, and the device/linker 200 in the field is a gateway The information may be collected when accessing 300 . Depending on the implementation, all or part of the management table recorded in the gateway may also be recorded in the linker 200 as the table 246 .

Alternatively, the gateway 300 (or the linker 200) may receive and manage in advance which standard and service the lower device is associated with. Here, Service ID means a specific service such as distribution automation, remote meter reading, and flight failure monitoring, etc., and Standard ID means a standard used in configuring the service, for example, a standard such as DNP, DLMS, LwM2M. Furthermore, based on the standard, information such as a factor to classify the message type to be sent from the upper stage to the terminal, a factor to check the resource block usage status, and RSSI to check the channel status of the terminal can be managed. have. The information defined in this way can be used to allocate air interface-side resources, and information on packet size and order for each service according to standard characteristics can be separately managed for easy implementation. Examples of this are shown in Tables 1 to 3 below.

The previously defined management information is defined as Session Context Information, and related information can be sent when requesting resource allocation. More specifically, in order to allocate a resource block for periodic data from the device side, information necessary for the resource management table 346 is provided by the following procedure.

The device-side linker 200 transmits a Session Creation Request to the gateway 300 for service registration, at this time, including Standard ID, Service ID, Source IP Address, Source Protocol Port, Destination IP Address, Destination Protocol Port, etc. send. After receiving the Session Creation Request, the gateway 300 generates Session Context Information for the device, stores it in the management table 346, and transmits it to the device-side linker 200 through a Session Creation Answer message including the Session creation result. .

If this is expressed in the LwM2M method, it can be expressed as follows. Through this, standards and service types can be checked, and in the case of periodic data, resources are allocated according to the periodicity data characteristics as defined above, and periodic resources are allocated based on this. In the case of aperiodic (one-time), it is possible to allocate as much as the size of the requested resource through the CCH resource and transmit the allocation information thereto to the device-side linker 200 to transmit data.

Based on the information transmitted through the above process, the resource block allocation method will be described in more detail as follows.

In the case of a distribution automation system, it can be divided into AI, AO, BI, and Counter types according to the characteristics of the information to be transmitted. The information to be sent is 445bytes, 186bytes, 426bytes, 104bytes for 30 seconds, 15 seconds, 1 second, 1 minute. information is transmitted in a cycle of When the distribution automation terminal (device) is registered, the gateway 300 may allocate and operate the resource block of the registration device according to data characteristics.

In order to facilitate block allocation of periodic data processing, a subframe is 100ms and 10 subframes are defined as one frame, so that a total of 1,000ms can be configured and operated. In the case of sending long periodic data, a frame can form a superframe by bundling 60 frames. In this structure, in order to send counter information according to the information transmission period defined above, the first resource of every frame When a block is allocated to a device and AO information is transmitted, a resource block can be allocated to the 15th frame and the 30th frame.

The SCH channel determines the size of the resource block according to the device's channel state (RSSI, speed) and the amount of data to be transmitted. In the case of sending 186 bytes of AO information, one resource block among the SCH channels composed of 5 resource blocks. can be assigned and operated. In addition, the resource allocation time and priority can be adjusted according to the QoS Level defined in the table. In particular, in the case of important data in the automation system, the Repetition function can be implemented to increase the communication success rate. In addition to the allocated resources, resource blocks for retransmission may be additionally allocated and retransmission may be performed.

10 is a block diagram illustrating the detailed configuration of the gateway 300 and the linker 200 for performing the above-described functions. From a hardware point of view, both the gateway 300 and the linker 200 are provided with a main memory such as a CPU and RAM, auxiliary storage devices, and wired/wireless communication modules for performing calculations. However, in FIG. 10, only functional blocks necessary for the description of the inventive concept are expressed.

The illustrated gateway 300 includes a communication layer module 320 having physical layers and lower layers for performing data communication with external devices; a resource management unit 340 for managing communication resources in a low-power wireless communication environment according to the spirit of the present invention; and an application module 360 having service applications for performing individual power-related services.

The illustrated linker 200 includes a communication layer module 220 having physical layers and lower layers for performing data communication with external devices; and a storage module 240 for storing information necessary for performing communication resource management in a low-power wireless communication environment according to the spirit of the present invention and for buffering data transmitted from the device.

The communication layer module 220 of the illustrated linker 200 includes a low-power wireless communication module 222 for forming a wireless communication channel with the gateway 300; and a device communication module 221 forming a data communication channel with the device 100 . The low-power wireless communication module 222 may be a CNL that performs an operation corresponding to the CNM of the gateway 300 described above, and the device communication module 221 may be an RS232/485 serial communication module.

The illustrated storage module 240 includes: a linker-side table 246 for recording information necessary for performing communication resource management in a low-power wireless communication environment in the form of a table; and a buffer 240 for buffering data transmitted from the device.

The communication layer module 320 of the illustrated gateway 300 includes an Ethernet module 326 for performing Ethernet communication by wire or wirelessly; a physical communication layer 322 for performing low-power wireless communication with the linker 200; and a CLink communication module 324 for forming a data communication channel with the linker 200 .

In order to perform the above-described functions, the illustrated gateway 300 includes a resource management unit 340 as a communication network manager (CNM, performing a task corresponding to CNL at the device end) that allocates resources for each service.

The illustrated resource management unit 340 largely includes a Packet Analyzer 342 that analyzes service-end (device-side) packets, and a Policy&Scheduler 344 that performs resource allocation and scheduling for each service (by device), and access. It holds a resource (resource) management table 346 for storing resource (communication resource) management information for a plurality of devices.

The resource management unit 340 (CNM) at the gateway side may create a management table 346 based on Session Context Information. Manage Session Context Information as much as the number of devices that require service. Management information may be the same as previously defined. Also, when the device is released, Session Context Information may be deleted.

FIG. 10 is a flowchart illustrating a data collection method using low-power wireless communication according to the spirit of the present invention in the linker-gateway system of FIG. 9 .

The method of collecting data generated by one or more devices using the illustrated low-power wireless communication includes the steps of setting a periodical (periodic communication) period and an on-demand (aperiodic communication) period (S100); a linker buffering data generated in the device (S200); forming a communication channel as prescribed in the periodic communication section, and forming a communication channel through negotiation between the linker (device-side wireless modem) and the gateway (server-side wireless modem) in the aperiodic communication section (S300); and transmitting buffered data from the linker to the gateway through the established communication channel (S400).

As described above, in the periodical (periodic communication) section, the synchronization securing channel (CCH) is operated only at the time point of each section regardless of the length of each periodic (periodic communication) section, and in the remaining sections, the data transmission channel ( SCH) can be operated.

Depending on the implementation, even in the on-demand (aperiodic communication) section, the synchronization securing channel (CCH) may be operated only at the time point of each section, and the data transmission channel (SCH) may be operated in the remaining sections. The length of the data transmission channel (SCH) following the channel should be described.

In the step of setting the communication section (S100), as described above, a periodic (periodic communication) section and an on-demand (aperiodic communication) section can be allocated according to the characteristics of data generated by the device, and the device and / or when the linker is newly installed or rebooted, and the linker connects (logins) to the gateway.

As shown, the step of forming the communication channel (S300) includes the steps of determining whether a time point for forming the communication channel is between a periodic (periodic communication) section and an on-demand (aperiodic communication) section (S310); If the period is a period, the step of checking the resource (communication resource) pre-allocated in the step S100 (S320); performing a negotiation on communication resource allocation between the linker and the gateway in case of an on-demand section (S340); and forming a wireless communication channel between the linker and the gateway using the allocated communication resource (S360).

The step of buffering the data (S200) is performed in parallel with the step (S300) of forming the communication channel. The time point at which data is generated by a device such as a sensor and the time point at which the wireless communication channel is formed according to the resource allocation are 100 % This is for case of mismatch. For example, as soon as the device generates data, the linker may buffer the generated data and transmit it to the gateway through the wireless communication channel of the period immediately started.

On the other hand, even in the on-demand (aperiodic communication) section, especially when the amount of data transmitted from the device is large and it takes a considerable amount of time to transmit, the linker and the gateway perform a negotiation on the allocation of communication resources (S340) in parallel Thus, the step of buffering the data (S200) may be performed. In this case, a communication resource (resource) sufficient for the corresponding capacity may be allocated at once by predicting the data capacity to be transmitted from the corresponding device during communication resource allocation negotiation.

The above-described methods may be usefully used in a remote meter reading system built in a machine type communication environment. Hereinafter, an implementation embodied as a remote meter reading system will be described. That is, based on the previously proposed method of data transmission and resource allocation in the periodical (periodic communication) section, the description will be made based on the AMI (Remote Meter Reading System), which is referred to as the MTC representative system.

11 is a transaction flow diagram illustrating a DLMS remote meter reading data collection process, and FIG. 12 is a data frame configuration diagram illustrating a DLMS packet structure.

13 is a bit table illustrating the structure of control field bits of DLMS, FIG. 14 is a packet conceptual diagram illustrating a DLMS service packet configuration, and FIG. 15 is a data frame configuration diagram illustrating a resource allocation scheme of periodic data.

The remote meter reading system is largely composed of a watt-hour meter (corresponding to a device), a modem (corresponding to a linker), a gateway (or DCU), and a meter reading server, and is operated as shown in FIG. 11 based on the DLMS (IEC62056) standard as a watt-hour meter interface standard. . To acquire power usage information, the upper stage communicates with the watt-hour meter, and at this time, based on the DLMS standard, the information collection process is performed in the order of mutual connection, request for necessary information, reception, and disconnection. In order to acquire one piece of meter reading information, a total of 10 information transfer procedures are required as shown, and information exchanged according to each process and required information is fixed and mutual communication is performed.

When performing such a procedure, the DLMS defines an interface format as shown in FIG. 12, and can classify each execution process according to a frame format. In addition, the information required to be collected uses the obis code of the information part to define information on the current time, LP, instantaneous value, forward wattage, power outage and restoration, etc. and operates in the form of collecting the corresponding information.

Based on this, in the embodiment of the present invention, if the service is enabled at the application stage, the CNM and CNL establish a scheduling procedure based on the authorized protocol information. At this time, taking the AMI as an example, it is defined as Service ID 6 (AMI) and Standard ID 0 (DLMS), and what collection process and resources are required by reading the control information of the input packet. For example, Packet Analyzer analyzes the control field bits information as defined in Figure 13, and in the case of UA service, the transmitted data checks a total of 35 bytes.

Based on this, the Scheduler allocates one SCH when it is assumed that one SCH can transmit 100 bytes. In this allocation method, the MCS value can be referred to as the amount of information that can be transmitted is different depending on the MCS (speed) between the device and the gateway section.

Furthermore, in the case of a system that exchanges data according to a continuous procedure, resources can be allocated in advance based on the predefined Service ID and Standard ID. For example, if it is assumed that one SCH block can transmit 100 bytes and has the following subframe structure, resources may be allocated in advance as shown in FIG. 13 according to the DLMS service flow.

In addition, in the case of AARE and GET-RES packets of DLMS, the amount of information may be different depending on the OBIS information to be sent. To this end, the Manager infers the amount of data to be transmitted by checking the tag information and OBIS information for checking the xDLMS Service of FIG. 15 and Table 4 as well as the Control information, and allocates resources based on this.

16 is a data frame configuration diagram illustrating a DNP interface of distribution automation.

17 is a packet conceptual diagram illustrating a distribution automation service flow (Request - Response).

The above-described methods may also be usefully used in a distribution automation system built in a machine type communication environment. However, in the distribution automation system, according to a request of an administrator (ie, an aperiodic situation), a significant amount of data from a specific device may be transmitted. In preparation for such a case, the following treatment method is proposed. Based on the proposed method, it can be applied to and utilized in the distribution automation system. In particular, it can be utilized in the process of collecting information measured by the device (device).

The server side sends request information to the device to collect measurement information, and the device that receives it sends response information as a response packet. As shown in FIG. 16, the packet is composed of a frame format of Start Byte (0564), Length, Control, Address, CRC, and Data, and information for distinguishing the characteristics of the frame is defined in the Control Byte. In Data, characteristic information such as DI, DO, AI, and AO is defined in the Group and Variation fields of Object. That is, the DNP data can predict the operation flow and packet size using only the control information and the object information of the data.

Accordingly, using the method proposed in the present invention, it can be implemented as follows. When a service is enabled at the application end, the CNM and CNL establish a scheduling procedure based on the authorized protocol information. At this time, taking DAS as an example, it is defined as Service ID 1 (DAS) and Standard ID 2 (DNP), and it reads the control information of the input packet and the object information of the data stage to check what collection process and resources are required.

For example, in the DNP environment according to Table 5 (DNP definition of processing switch), control field bits information is used. If PRM information is 1, it is Request, if it is 0, it is Response. Object information in the data frame is defined as in the table below. and is in operation. Such information can be stored and managed using a predefined table.

As mentioned above, when the request information of the AI Object Group that requires the entire measurement is requested, 280Bytes information is transmitted from the device side, and the total delay time is 1,040 ~ 1,640ms. In particular, in the distribution automation environment, it was confirmed that the delay time due to the serial communication between the linker-device section occupies a large proportion. By doing so, the communication delay time of the serial section can be minimized. That is, in this case, the linker may include an internal module similar to the CNM of the gateway, which performs not only the above-described CNL function, but also a packet analyzer function and a scheduler function.

More specifically, the Packet Analyzer implemented in the linker analyzes the received information and recognizes that it is a packet requesting measurement information, and the Scheduler in the linker transmits the request information for the measurement information to the device and at the same time sends the request information to the gateway. A resource (communication resource) block request for transmitting 300 bytes of information is performed. In particular, the scheduler in the linker can minimize the delay time by requesting resources by checking the delay time according to the communication method, speed, and packet size between the wireless modem and the device in advance. Through this, resources can be allocated in advance at the time of data transmission between the wireless modem and the device.

The gateway allocates a resource block to the allocation request, and the wireless modem receives response information to the previously requested information from the device. At this time, as the previously requested resource is allocated in advance, the received data can be directly transmitted without delay.

18 is a transaction flow diagram illustrating a distribution automation operation flow utilizing the method of concurrently performing the above-described data buffering and resource allocation negotiation.

When the linker 200 performing the illustrated process receives a request for data transmission of the connected device from the gateway 300 , the linker 200 sends the data to the gateway 200 according to the characteristics of the data generated by the device recorded in the storage module 240 . At the same time as requesting communication resource allocation, it instructs data transmission to the device.

The total delay time through the method shown in FIG. 18 takes a maximum of 840 ms by processing the sections E and F of FIG. 2 at the same time, and by shortening the maximum of 1,000 ms compared to the method of FIG. 2, real-time, which is a requirement of automation can satisfy

Those skilled in the art to which the present invention pertains should understand that the present invention can be embodied in other specific forms without changing the technical spirit or essential characteristics thereof, so the embodiments described above are illustrative in all respects and not restrictive. only do The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

100: device (terminal)
200: linker
220: communication layer module
240: storage module
300 : gateway
320: communication layer module
340: resource management department
360: application module
400: platform

Claims (17)

A system for collecting data generated by one or more devices using low-power wireless communication, comprising:
a linker that receives data generated from the device and transmits it through low-power wireless communication; and
A gateway that performs data communication with a server-side terminal and receives data from the linker through low-power wireless communication,
When the linker and the gateway perform communication by receiving communication resources allocated in units of time slots, a periodical interval for forming a communication channel defined in advance on a regular basis and an on-demand interval for forming a communication channel by negotiating each time it occurs Perform communication by classifying in advance,
In the periodical section, as each periodic communication section, the synchronization securing channel (CCH) is operated only at the time point of each section regardless of the length of the periodic section, and the data transmission channel (SCH) is operated in the remaining sections,
The gateway is
and a resource management table in which characteristics of data generated in each device are described with respect to the one or more devices,
When the linker logs in, the linker-gateway system searches for data characteristics of a device connected to the linker in the resource management table and allocates the periodic communication section according to the retrieved data characteristics.
According to claim 1,
The server-side terminal and the gateway perform Ethernet-type communication,
The gateway and the linker perform communication based on a DLMS protocol,
The linker and the device are linker-gateway system for performing RS232/485 serial communication.
delete According to claim 1,
In the on-demand section,
A linker-gateway system in which a synchronization securing channel (CCH) is operated only at the time point of each section and a data transmission channel (SCH) is operated in the remaining sections, but the length of a data transmission channel following the synchronization securing channel is described.
delete delete According to claim 1,
The linker is
Linker-gateway system including a storage module for temporarily storing the data received from the device before transmitting to the gateway.
8. The method of claim 7,
The storage module records the characteristics of data to be transmitted from the connected device,
When the linker receives a request for data transmission of the device from the gateway, the linker requests the gateway to allocate communication resources according to the characteristics of the recorded data and at the same time instructs the device to transmit data.
a linker that receives data generated from one or more devices and transmits it through low-power wireless communication; and
A method of collecting data generated by the devices using a gateway that performs data communication with a server-side terminal and receives data from the linker through low-power wireless communication, comprising:
setting a periodical section as a periodic communication section and an on-demand section as an aperiodic communication section;
buffering data generated from the device;
forming a communication channel as prescribed in the periodical section, and forming a communication channel through negotiation between the linker and the gateway in the on-demand section;
transmitting buffered data from the linker to the gateway through an established communication channel;
including,
In the periodical section, as each periodic communication section, the synchronization securing channel (CCH) is operated only at the time point of each section regardless of the length of the periodic section, and the data transmission channel (SCH) is operated in the remaining sections,
The gateway includes a resource management table in which characteristics of data generated by each device are described with respect to the one or more devices,
In the step of setting the periodical section as the periodic communication section and the on-demand section as the aperiodic communication section,
When the linker logs in, a data collection method using low power wireless communication for searching for data characteristics of a device connected to the linker from the resource management table and allocating the periodic communication section according to the retrieved data characteristics.
delete 10. The method of claim 9,
In the on-demand section,
The synchronization securing channel (CCH) is operated only at the time of each section, and the data transmission channel (SCH) is operated in the remaining sections, but data collection using low-power wireless communication describing the length of the data transmission channel following the synchronization securing channel Way.
delete delete delete 10. The method of claim 9,
Forming the communication channel comprises:
determining whether a time point at which a communication channel is to be formed is between a periodic period and an on-demand period;
checking a pre-allocated communication resource if the period is a period;
performing, by the linker and the gateway, negotiation for communication resource allocation in the on-demand section; and
Forming a wireless communication channel between the linker and the gateway using the allocated communication resources
Data collection method using low-power wireless communication comprising a.
16. The method of claim 15, wherein when the amount of data transmitted by the device is large and a significant transmission time is required,
A data collection method using low-power wireless communication, wherein the step of buffering the data is performed in parallel with the step of the linker and the gateway negotiating communication resource allocation.
delete

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