Low-voltage power grid communication dual-mode protocol stack implementation method

Abstract

The invention relates to the technical field of power grid equipment communication, and discloses a low-voltage power grid communication dual-mode protocol stack implementation method, which comprises a physical layer, a data link layer and an application layer, the physical layer integrates two physical layer architectures of an HPLC physical layer and an HRF physical layer at the same time, and the two physical layers are connected with each other through a PMD layer and a PLCP layer which are independent but have a unified interaction interface. Data interaction with a hardware bottom layer of the communication unit is realized; the data link layer comprises a media access control sub-layer and a dynamic network management sub-layer NET, the media access control sub-layer comprises an HPLC (High Performance Liquid Chromatography) collaboration sub-layer and an HRF (High Performance Radio Frequency) collaboration sub-layer, and each collaboration sub-layer comprises an LLC (Logical Link Control) sub-layer and an MAC (Media Access Control) sub-layer and corresponds to the two physical layers; and the network management sub-layer synthesizes the effectiveness of the dual-mode channel and selects the most reasonable path as a service path. Through the modular design, normalization of a wireless link and a carrier link is realized, and the communication reliability in a complex power grid environment is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid equipment communication, and particularly to a method for implementing a dual-mode protocol stack for low-voltage power grid communication. Background Art

[0002] With the continuous development of power grid communication technology, power lines are used as communication media for data transmission, experiencing the development from narrowband carrier to broadband high-speed carrier communication. Its communication rate and success rate are constantly increasing, but there are still some scenarios where carriers cannot communicate. Wireless communication technology can effectively make up for this shortcoming. At this time, the combination of broadband high-speed carrier and wireless communication technology can effectively improve the success rate of low-voltage power communication. The dual-mode communication technology in the power communication network not only retains the advantages of high speed and high efficiency of broadband carrier, but also makes up for the dead corners of carrier communication.

[0003] The dual protocol is a high-speed carrier communication and wireless communication protocol formulated for the interconnection and interoperability between communication units, and this protocol is applied to power grid communication unit devices.

[0004] The development of the dual protocol for communication units requires that the device can both transmit and receive on the carrier link and on the wireless channel. This requires a method that can realize the simultaneous operation of the carrier and wireless protocol stacks to meet the requirements of the dual protocol for communication units and realize the normalization of the wireless link and the carrier link. Developing a method for implementing the dual protocol stack for communication units has also become an urgent problem to be solved. Summary of the Invention

[0005] Aiming at the technical defects of insufficient reliability of a single transmission mode and difficult coordination of heterogeneous protocol stacks in existing low-voltage power grid communication, the present invention proposes a method for implementing a dual-mode protocol stack for low-voltage power grid communication. This method realizes the dual-mode collaborative transmission of broadband power line carrier (HPLC) and power wireless private network (HRF) by constructing a heterogeneous protocol fusion architecture, effectively improving the communication reliability in a complex power grid environment.

[0006] The technical solution of the present invention is realized through the following innovative architecture: This dual-mode protocol stack adopts a three-layer architecture design, including a heterogeneous physical layer, an intelligent data link layer, and a service-oriented application layer.

[0007] The heterogeneous physical layer is different from the traditional single physical layer, and integrates two physical layer architectures, namely the HPLC physical layer and the HRF physical layer. The two physical layers respectively realize data interaction with the hardware bottom layer of the communication unit through the independent but unified interface PMD layer and PLCP layer.

[0008] The intelligent data link layer includes a media access control sublayer and a dynamic network management sublayer. The media access control sublayer includes two cooperative sublayers, HPLC and HRF, and each cooperative sublayer includes two sublayers, LLC and MAC. LLC completes all data link layer requirements, including data framing, data queuing, and time slot matching; the MAC sublayer completes channel access, and based on the enhanced CSMA / CA mechanism and the time slot allocation mechanism of TDMA, realizes reliable data transmission between dual channels and multiple nodes. The network management sublayer realizes the networking, network maintenance, routing management of the dual-mode communication network, and the aggregation and distribution of application layer messages. By synthesizing the effectiveness of the dual-mode channels, it normalizes the wireless link and the carrier link, and selects the most reasonable path as the service path.

[0009] The service-oriented application layer includes the LOCAL layer and the APP layer, and realizes the service data interaction between local communication units based on the heterogeneous physical layer and the intelligent data link layer, including multi-level priority queue management, real-time control instruction queue, metering data collection queue, and bulk transmission task queue, and completes the priority scheduling processing of the corresponding tasks.

[0010] As described above, a method for implementing a dual-mode protocol stack for low-voltage power grid communication according to the present invention has the following beneficial technical effects: This protocol stack realizes the technical requirements of being able to transmit and receive on both the carrier link and the wireless channel on the same device, realizes the normalization of the wireless link and the carrier link, and effectively improves the communication reliability in a complex power grid environment. Description of the Drawings

[0011] Figure 1 It is a hierarchical division diagram of the communication protocol stack of the present invention.

[0012] Figure 2 It is an overall architecture diagram of the dual-mode communication protocol stack described in the present invention. Detailed Embodiments

[0013] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the present invention.

[0014] As Figure 1 shown, a method for implementing a dual-mode protocol stack for low-voltage power grid communication provided by the present invention, the protocol stack includes a physical layer, a data link layer, and an application layer, and the data link layer includes a network management sublayer and a media access control sublayer.

[0015] The physical layer includes two physical layers, HPLC and HRF, which implement: encoding and modulating the data packets of the data link layer into high-speed carrier signals or high-speed wireless signals, and sending them onto the power line medium or radiating them into space; receiving the high-speed carrier signals on the power line medium or the high-speed wireless signals radiated into space, demodulating them into data packets, and delivering them to the data link layer for processing. The two physical layers, HPLC and HRF, respectively include a PMD layer and a PLCP layer to implement the underlying data interaction of the communication unit hardware.

[0016] The data link layer includes a network management sub-layer NET and media access control sub-layers LLC, MAC. The network management sub-layer implements the networking, network maintenance, routing management of the dual-mode communication network, and the aggregation and distribution of application layer packets. The media access control sub-layer competes for the physical channel through two channel access mechanisms, CSMA, CA and TDMA, and the wireless channel scanning, selection and switching mechanism to achieve the reliable transmission of data packets between the two channels and multiple nodes. Further, corresponding to the two physical layers, HPLC and HRF, there are also two media access control sub-layers that respectively control the channel access of the two channels. The network management sub-layer then normalizes the wireless link and the carrier link by integrating the effectiveness of the dual-mode channels, and selects the most reasonable path as the service path.

[0017] The application layer implements the service data interaction between local communication units and communication units, service priority scheduling, completes data transmission through the data link layer, and simultaneously completes the execution of services with advanced functions.

[0018] As Figure 2 shown, the overall architecture implemented by the dual protocol stack in the embodiment of the present invention includes layers LOCAL, APP, NET, LLC, MAC, PLCP, PMD, UART, where LLC, MAC, PLCP, PMD respectively have two independent levels for HPLC and HRF, denoted as LLC(PLC), LLC(RF), MAC(PLC), MAC(RF), PLCP(PLC), PLCP(RF), PMD(PLC), PMD(RF).

[0019] Specifically, in this embodiment, the message interaction method for each layer is implemented using threads. MAC waits for the mailbox, and LLC, NET, APP, and UART wait for events (a unified thread structure) to achieve event-driven. The threads are divided into data service interaction and management service interaction. The data service mainly involves the sending and receiving of PLC, RF, and UART messages, and the management service includes non-data content specified by various protocols. When the underlying layer provides services, it requires a service provider function interface, and relevant message passing is completed inside the function, including service parameters passed to the underlying layer through parameter passing. After recording the parameters inside the function, it sends a mailbox or an event to itself. When the service is a request or response service, a service completion callback function is registered in the service request interface. When the service is completed, the message is passed to the service recipient through the callback function registered during the request. For reporting services, a callback function for upward message passing is provided, and the callback function is registered during the high-level initialization (service subscription), and this function completes the message reporting to the high-level.

[0020] The PMD (physical medium dependent) sublayer is implemented by hardware and provides a method for data sending and receiving between stations, mainly implementing modulation and demodulation algorithms for data sending and receiving. The PLCP (physical layer convergence procedure) sublayer is implemented by software and provides aggregation of services for the PMD sublayer, providing the same service interface for different PMD sublayers and providing a unified data and parameter service model for channel access of the MAC sublayer. The MAC (medium access control) sublayer is implemented by software and mainly completes channel access. In the current system, it is mainly CSMA / CA, and it also supports the simplest TDMA access. The LLC (logical link control) sublayer is implemented by software and mainly completes all other data link layer requirements, including data framing, data queuing, time slot matching, etc.

[0021] The PLCP contains a message reporting callback function for sending messages to the MAC layer. The PLCP needs to provide a registration interface, which is called during the initialization of the MAC layer to complete the association between the two. The MAC is suspended on fetching messages from the mailbox. There are three types of messages fetched by the MAC: PLCP messages (message sequences related to data transmission and reception), MAC messages (messages for timer overflows inside), and LLC messages (data transmission request messages). Since only pointers can be used to pass messages through the mailbox, the MAC needs to apply for relevant space to maintain the message entities. At the same time, since the same message will not be generated repeatedly in a short period, only one entity space is required for relevant messages. The LLC is suspended on waiting for the event set, providing a data transmission interface upwards. After the high-level application finishes enqueuing data, it notifies this event through the event set. The LLC needs to maintain two MACs and decide which MAC to enable currently. Since they are used serially with the MAC, it is necessary to do a good job in context correspondence for determining which MAC the current confirmation comes from. Both the NET and APP are suspended on the event set, waiting for the arrival of the upstream packet and processing the packet. Both the LOCAL and UART are suspended on the event set. The LOCAL thread is suspended on waiting for the event set, waiting for the serial port queue and the PLC queue to be non-empty. The UART thread only performs serial port data transmission and reception and packet extraction and processing.

[0022] As described above, a method for implementing a dual-mode protocol stack for low-voltage power grid communication according to the present invention has the following beneficial technical effects: This protocol stack solves the problem that on the same device, it can achieve transmission and reception on the carrier link and also on the wireless channel, realizing the normalization of the wireless link and the carrier link.

[0023] The above embodiments are descriptions of the specific implementation manners of the present invention, rather than limitations on the present invention. Those skilled in the relevant technical fields can also make various transformations and changes to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. A method for implementing a dual-mode protocol stack for low-voltage power grid communication, comprising a physical layer, a data link layer, and an application layer, characterized in that: The application layer includes the LOCAL layer and the APP layer to realize the business data interaction between local communication units; the data link layer includes the media access control sublayer and the dynamic network management sublayer NET, the media access control sublayer includes two collaborative sublayers, HPLC and HRF, each collaborative sublayer includes two sublayers, LLC and MAC; the physical layer integrates two physical layer architectures, HPLC physical layer and HRF physical layer, and the two physical layers realize data interaction with the bottom layer of the communication unit hardware through the independent PMD layer and PLCP layer with unified interactive interface; the dual-mode protocol stack also includes the UART layer; wherein LLC, MAC, PLCP, and PMD have two independent layers, HPLC and HRF, respectively; Among them, the PMD sublayer is implemented by hardware, providing a method for sending and receiving data between sites and realizing the modulation and demodulation algorithm for data sending and receiving; the PLCP sublayer is implemented by software, providing aggregation of PMD sublayer services, providing the same service interface for different PMD sublayers, and providing a unified data and parameter service model for the channel access of the MAC sublayer; LLC completes all data link layer requirements, including data framing, data queuing, and time slot matching; the MAC sublayer completes channel access and realizes reliable data transmission between dual channels and multiple nodes based on the enhanced CSMA / CA mechanism and TDMA time slot allocation mechanism; the network management sublayer NET realizes the networking, network maintenance, routing management and application layer message aggregation and distribution of the dual-mode communication network, integrates the effectiveness of the dual-mode channel, normalizes the wireless link and the carrier link, and selects the most reasonable path as the service channel.

2. A method for implementing a low-voltage power grid communication dual-mode protocol stack according to claim 1, characterized in that: The message interaction mode of each layer in the low-voltage power grid communication dual-mode protocol stack is implemented using threads. MAC realizes event-driven by waiting for mailboxes, and LLC, NET, APP, and UART realize event-driven by waiting for events. The threads are divided into data service interaction and management service interaction. Data services include the sending and receiving of PLC, RF, and UART messages, and management services include non-data content specified by various protocols. When the bottom layer provides services, the service provider function interface must complete the relevant message transmission inside the function, including passing the service parameters to the bottom layer through parameters, and the function records the parameters inside and sends the mailbox or event to itself. When the service is a request or reply service, the service completes the registration of the callback function in the service request interface. When the service is completed, the message transmission to the service recipient is completed through the callback function registered at the time of the request. The reporting service provides a callback function for transmitting messages upward, and the callback function is registered when the high layer is initialized. The function completes the message reporting to the high layer; the PLCP layer includes a message reporting callback function for sending messages to the MAC; The PLCP layer needs to provide a registration interface, which is called by MAC during initialization to complete the association between the two.

3. According to claim 1, a method for implementing a low-voltage power grid communication dual-mode protocol stack is characterized in that: The method comprises the following steps: the MAC layer is suspended on getting messages from the mailbox. There are three types of messages taken out by the MAC layer, namely, PLCP layer messages, MAC layer messages, and LLC layer messages. Since the mailbox can only pass messages through pointers, the MAC layer needs to apply for relevant space to maintain the message entity, and the message only needs one physical space. The LLC layer is suspended on the waiting event set, and provides a data sending interface to the upper layer. After completing the data enqueue, the high-level application notifies the event through the event set. The LLC layer needs to maintain two MAC layers and decide which MAC layer is currently enabled; Both the NET layer and the APP layer are suspended on the event set, waiting for the arrival of the uplink message and processing the message; Both the LOCAL layer and the UART layer are suspended on the event set, and the LOCAL thread is suspended on the waiting event set, waiting for the serial port queue to be non-empty and the PLC queue to be non-empty; The UART thread only performs serial port data transmission and reception, and message extraction and processing.

Images