CN115915412A - Channel access method based on dual-mode network - Google Patents

Abstract

The invention discloses a channel access method based on a dual-mode network, which comprises the following steps: before a network runs, a concentrator CCO node acquires a node MAC address list based on a white list mechanism, so that a dual-mode node in the MAC address list is accessed to the network when the CCO node runs in the network; the identity of each dual-mode node in the network is identified through the short address; according to the short address of the dual-mode network node, allocating the use right to the time slot structures of the beacon periods on the carrier channel and the wireless channel according to a preset allocation use mechanism, so as to transmit signals according to the allocation of the use right; the beacon period comprises N +1 sub-frames, N is the number of the dual-mode nodes in the MAC address list, the time slot structure of each sub-frame is consistent, and the time slot structure of each sub-frame comprises a dual-function time slot and a CSMA time slot area. The invention can reduce the channel overhead, has strong robustness and can maintain the stable operation of the whole network under the complex channel environment.

Description

Channel access method based on dual-mode network

Technical Field

The invention relates to the technical field of power internet of things, in particular to a channel access method based on a dual-mode network.

Background

As an important component of the national infrastructure, the high-speed carrier communication technology is the most widely used communication technology in the system because of its excellent communication performance and the natural link between power line communications. With the continuous development of microelectronic technology, the power consumption and the volume of a communication chip are continuously reduced, and the quantitative production of a dual-mode chip has engineering feasibility, so that the high-speed carrier and high-speed wireless dual-mode communication technology becomes the main development direction of the next generation of power internet of things communication technology. By 8 months 2021, national grid companies have completed the work of making physical layer labels for the dual mode, but have not yet determined the work of making standards for the link layer.

The channel access mechanism is one of the core contents of a link layer protocol, and the mechanism determines the signal transmission timing and the access process of a network node in a common channel, and is a key technology which influences the comprehensive communication performance of the whole network. Therefore, a new physical layer communication mode based on dual-mode communication is needed, and a new efficient integrated channel access protocol is researched to maximize the integrated communication performance of the dual-mode network.

Disclosure of Invention

The invention provides a channel access method based on a dual-mode network, which aims to solve the problem of how to efficiently synthesize a channel access protocol and maximize the comprehensive traffic performance of the dual-mode network.

In order to solve the above problem, according to an aspect of the present invention, there is provided a channel access method based on a dual mode network, the method including:

before a network runs, a concentrator CCO node acquires a node MAC address list based on a white list mechanism, so that a dual-mode node in the MAC address list is accessed to the network when the CCO node runs in the network;

the identity of each dual-mode node in the network is identified through a short address; the short address of the CCO node is defaulted to 0, when slave nodes on the MAC address lists of other nodes access the network, the CCO node allocates a short address for the slave nodes, and the value range is [1, N ];

according to the short address of the dual-mode network node, respectively allocating the use rights to the time slot structures of the beacon periods on the carrier channel and the wireless channel according to a preset allocation use mechanism, so as to transmit signals according to the allocation of the use rights;

the double-mode network refers to a carrier channel and a wireless channel, the beacon period comprises N +1 subframes, N is the number of double-mode nodes in the MAC address list, the time slot structure of each subframe is consistent, and the time slot structure of each subframe comprises a double-function time slot and a CSMA time slot area.

Preferably, the method allocates the usage right to the time slot structure of the beacon period on the carrier channel according to the preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, and includes:

aiming at a time slot structure of a new beacon period on a carrier channel, a network node with a short address of n has priority use right on a carrier dual-function time slot of a subframe n;

for carrier subframe 0, the carrier dual-function time slot is fixedly allocated to the CCO node and used for transmitting the central beacon signal, the length of the carrier dual-function time slot is set to be T, and the time slot with the length of the first 2T of the subsequent CSMA time slot area only allows the CCO to transmit the central beacon signal;

for a carrier subframe n, if a node with a short address of n is a proxy node PCO on the carrier side, the time slot is fixedly allocated to the node n for the node n to send a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

Preferably, wherein the method further comprises:

when a CCO node receives signals in a CSMA time slot area, the receiving phase is adjusted according to the number of the subframe, wherein the number of the subframe is k, when the remainder of k modulo division 3 is 0, 1 and 2, the corresponding receiving phases are an A phase, a B phase and a C phase in sequence, and when the node sends signals to the CCO node in the CSMA time slot area, the receiving phase of the CCO node and the CSMA time slot area of the subframe with the same phase are selected to send the signals based on the phase of the CCO node.

Preferably, the specific length of the carrier dual function timeslot is equal to the transmission length of the beacon signal when the length of the signaling content in the frame payload signal reaches a prescribed upper limit for the timeslot structure of the new beacon period on the carrier channel.

Preferably, the method allocates the usage right to the time slot structure of the beacon period on the wireless channel according to the preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, and includes:

aiming at the time slot structure of a beacon period on a wireless channel, a network node with a short address of n has priority use right on the wireless dual-function time slot of a subframe n;

for wireless subframe 0, the wireless dual-function time slot is fixedly allocated to the CCO node and used for transmitting a central beacon signal;

for a wireless subframe n, if a node with a short address n is a proxy node PCO on a wireless side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

Preferably, the specific length of the wireless dual function slot is equal to the transmission length of the beacon signal when the length of the beacon signal signaling content reaches the specified upper limit, for the slot structure of the new beacon period on the wireless channel.

Preferably, the method minimizes the length of the signaling content in the beacon signal by using the following three proxy node message formats, including:

first agent node message format: beacon entry head + proxy node message number + number of proxy nodes + full list of proxy nodes; second agent node message format: beacon entry header + proxy node message number; third agent node message format: the method comprises the steps that a beacon entry head, a proxy node message number, the number of newly-added proxy nodes, a newly-added proxy node list, the number of newly-subtracted proxy nodes and a newly-subtracted proxy node list are added;

wherein the beacon entry header is used to identify the type of beacon message; the proxy node message number is used for identifying the time sequence of the message content; in the operation process of the network, in the idle period of the network service, the CCO node uses the message format of the first proxy node and carries the short addresses of all the proxy nodes in the central beacon signal; during periods of high network traffic load, the CCO node uses either the second proxy message format or the third proxy message format to minimize the signaling content length in the beacon signal.

Preferably, wherein the method further comprises:

if the agent node message adopts a first agent node message format and the message number is higher than the message number kept by the node after one node receives the beacon signal, updating the agent node information; if the message format is the second agent node message format and the message number is equal to the message number kept by the second agent node, the change is not needed; if the message format is the third agent node message format and the message number is only 1 greater than the message number kept by the third agent node message format, updating the agent node list according to the content of the message number; if an agent node message is received, the message number of which is only more than or equal to 2 than the message number of the agent node message and the format of which is the second agent node message format or the third agent node message format, the agent node sends a request to the agent node of the agent node in the CSMA time slot area, the agent node is required to send a latest numbered agent node list to the agent node of the agent node, and after the agent node receives the request, the agent node sends the agent node list by using the first agent node message format in the next beacon period.

Preferably, wherein the method further comprises:

the CSMA time slot area of the subframe with the number of n only allows the node with the short address of n and the 1-hop neighbor node thereof to use, and if the node with the number of n does not enter the network, the substitute is a CCO node; the 1-hop neighbor node monitors a synchronous signal head from the starting time position of the subframe, if the synchronization is successful, a subsequent signal is received, and after the signal reception is completed, the remaining time slot resources of the subframe are CSMA time slot areas; if the synchronization fails, the priority node of the whole subframe does not send signals on the dual-purpose time slot of the beacon period, except the length of the synchronization head signal, the rest time slot resources of the subframe are CSMA time slot areas; where a 1-hop neighbor node is a node that is capable of correctly receiving signals transmitted on the dual-function slot of the sub-frame.

The invention provides a channel access method based on a dual-mode network, and provides a new time slot structure of a beacon period, which comprises a dual-function time slot and a CSMA time slot area, wherein a concentrator CCO node acquires a node MAC address list based on a white list mechanism before the network runs, so that the dual-mode node in the MAC address list is accessed to the network when the CCO node runs in the network; the identity of each dual-mode node in the network is identified through the short address; according to the short address of the dual-mode network node, respectively allocating the use rights to the time slot structures of the beacon periods on the carrier channel and the wireless channel according to a preset allocation use mechanism, so as to transmit signals according to the allocation of the use rights; the channel access method can reduce the channel overhead, meet the ordered channel access requirement of the dual-mode node with higher efficiency, has simple protocol content and strong robustness, and can maintain the stable operation of the whole network under a more complex channel environment.

Drawings

Exemplary embodiments of the invention may be more completely understood in consideration of the following drawings:

FIG. 1 is a schematic diagram of a carrier network tree network topology;

FIG. 2 is a schematic diagram of a network division in a time axis in a national network protocol;

fig. 3 is a flowchart of a channel access method 300 based on a dual mode network according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a dual-mode network divided in a time axis according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating a physical layer transmission format of a carrier signal according to an embodiment of the invention;

fig. 6 is a schematic diagram of a slot structure of a carrier-side subframe 0 according to an embodiment of the present invention;

fig. 7 (a), (b), and (c) are schematic diagrams of a first proxy node message format, a second proxy node message format, and a third proxy node message format, respectively, according to an embodiment of the present invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same unit/element is denoted by the same reference numeral.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their context in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

In a high-speed carrier communication protocol, a tree topology and a beacon mechanism are two core contents, wherein the tree topology refers to: the carrier network generally forms a multi-level association tree network with a concentrator (CCO) as a center and a proxy node (PCO) as a relay agent, and connects all Slave Stations (STAs), as shown in fig. 1. The reasons for using the tree topology for network route establishment and maintenance are: one node of the source node and the sink node of all service messages in the network is required to be a CCO, wherein a service with the sink node being the CCO is called an uplink service message, and a service with the source node being the CCO is called a downlink service message. That is, except for CCO, any two nodes in the network do not communicate with each other in the form of service packets by using the other node as the sink node.

And the beacon mechanism refers to: the CCO operates as a central control node for network communications using a beacon period based superframe slot structure, while maintaining synchronization and orderly operation of the entire network using beacon signals. In the high-speed carrier communication protocol established by the national grid company, the time slot division of the network in one beacon period is shown in fig. 2. In a high-speed carrier communication protocol established by southern power grid companies, a similar frame structure is adopted, but the 4 time slots are different from the national grid in sequence, namely a beacon time slot area, a CSMA time slot area, a TDMA time slot area and a binding CSMA time slot area.

In order to allow all network nodes to acquire the relevant timeslot parameters in the beacon period, the central beacon signal of the CCO uses the timeslot allocation message to define the timeslot allocation parameter of one beacon period in fig. 2, which is specifically shown in table 1 below.

TABLE 1 content definition of the Slot Allocation message field

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The time slot distribution of the beacon period in fig. 2 supports the operation of the beacon system and the tree topology, but has two disadvantages:

1. the service delay is large: a large number of beacon time slots are closely connected, so that the length of a beacon time slot area is long, and a node cannot transmit services in the period, so that a large waiting time delay occurs in data services generated at the time stage;

2. the overhead of the beacon slot is large: because the time slot structure of the beacon period is complex and the parameters are numerous, the beacon signal needs to be explained by using a large amount of signaling content, so that the length of the beacon signal is long, and more channel resources are occupied;

based on the analysis, the invention provides a novel channel access scheme aiming at the newly supported dual-mode communication capability of a physical layer, and provides a novel time slot division mechanism of a beacon period and a corresponding signal transceiving rule under the condition of inheriting the basic idea of network operation and maintenance of a beacon system and a tree-shaped topological structure of an original high-speed carrier link layer protocol, so that the signaling content length of a beacon signal can be effectively simplified, and the channel overhead is reduced; meanwhile, the uniform and distributed distribution of the beacon time slots can reduce the waiting time delay of service transmission, thereby laying a foundation for improving the comprehensive communication performance of the dual-mode network. The concrete content is as follows:

fig. 1 is a flow chart of a channel access method 100 based on a dual-mode network according to an embodiment of the present invention. As shown in fig. 1, the channel access method based on the dual-mode network according to the embodiment of the present invention provides a new timeslot structure of a beacon period, which includes a dual-function timeslot and a CSMA timeslot area, and can reduce channel overhead, meet the ordered channel access requirement of the dual-mode node with higher efficiency, and the protocol content is simple but the robustness is strong, and the smooth operation of the entire network can be maintained in a complex channel environment. The channel access method 100 based on the dual-mode network provided by the embodiment of the invention starts from step 101, and before the network operation of the concentrator CCO node in step 101, a node MAC address list is obtained based on a white list mechanism, so that the dual-mode node in the MAC address list is accessed to the network when the CCO node is in the network operation process.

In step 102, the identity of each dual-mode node in the network is identified through a short address; the short address of the CCO node defaults to 0, when the slave nodes on the MAC address lists of the other nodes access the network, the CCO node allocates a short address to the slave nodes, and the value range is [1, N ].

In step 103, according to the short address of the dual-mode network node, the time slot structures of the beacon periods on the carrier channel and the wireless channel are respectively allocated with the use rights according to a preset allocation use mechanism, so as to transmit signals according to the allocation of the use rights;

the beacon period comprises N +1 sub-frames, N is the number of the dual-mode nodes in the MAC address list, the time slot structure of each sub-frame is consistent, and the time slot structure of each sub-frame comprises a dual-function time slot and a CSMA time slot area.

In the present invention, the division of the dual-mode network on the time axis is specifically shown in fig. 4, and one beacon period includes N +1 subframes, where N refers to the number of dual-mode network nodes in the CCO white list. The white list mechanism means that before the network starts to operate, the CCO realizes manual input of a node MAC address list. And the CCO node only runs the node access on the list during the network operation process.

Based on the time slot structure of fig. 4, in the channel access mechanism corresponding to the dual-mode network, the upper limit of the dual-mode network node scale is consistent with the specification of the original high-speed carrier communication standard, and the number of the nodes is 1015. The dual-mode network uses a short address with the length of 12 bits to identify the identity of a dual-mode node in the network, wherein the short address of the CCO node is defaulted to be 0, and when the slave nodes on the rest white lists are accessed to the network, the CCO node allocates a short address for the CCO node, and the value range is [1, N ]; the slot structure of each sub-frame is kept consistent and consists of two slots, specifically a dual function slot and a CSMA slot area.

Description of the invention: the above-mentioned time slot structure of the beacon period is premised on the capability of the carrier channel and the radio channel of the physical layer to operate simultaneously, including the capability of transmitting and receiving signals simultaneously, and transmitting signals and receiving signals one by one.

Preferably, the method allocates the usage right to the time slot structure of the beacon period on the carrier channel according to the preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, and includes:

aiming at a time slot structure of a new beacon period on a carrier channel, a network node with a short address of n has priority use right on a carrier dual-function time slot of a subframe n;

for carrier subframe 0, the carrier dual-function time slot is fixedly allocated to the CCO node and used for transmitting the central beacon signal, the length of the carrier dual-function time slot is set to be T, and the time slot with the length of the first 2T of the subsequent CSMA time slot region only allows the CCO to transmit the central beacon signal;

for a carrier subframe n, if a node with a short address n is a proxy node PCO on the carrier side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to the node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

Preferably, wherein the method further comprises:

when a CCO node receives signals in a CSMA time slot area, the receiving phase is adjusted according to the number of a subframe, wherein the number of the subframe is k, when the remainder of dividing k by module 3 is 0, 1 and 2, the corresponding receiving phase is an A phase, a B phase and a C phase in sequence, and when the node sends signals to the CCO node in the CSMA time slot area, the receiving phase of the CCO node and the CSMA time slot area of the subframe with the same phase as the self phase are selected to send the signals based on the self phase.

In the invention, in a channel access mechanism based on a beacon period, aiming at a beacon period time slot structure on a carrier channel, a pre-allocation use mechanism is adopted for a carrier dual-function time slot of each subframe, namely, a network with a short address of n has a priority use right for the carrier dual-function time slot of the subframe n. The specific rule is as follows:

(1) The specific length of the carrier dual-function time slot is equal to the sending length of the beacon signal when the length of the signaling content in the frame loading signal reaches the specified upper limit. The format for the physical layer to transmit a signal is shown in fig. 5, the signal formats of the sync header and the frame control signal of all signals are fixed, and the signal format of the frame payload signal is determined by its specific data length and its corresponding modulation and coding scheme.

Note: in the existing national network high-speed carrier protocol, the coding length of the frame carrier signal of the beacon signal is fixed to 136 bytes or 520 bytes.

(2) The carrier network uses power lines as its signal transmission channels, while domestic power lines are three-phase four-wire system, so there are three parallel communication channels of a/B/C phase, where the CCO needs to support alternate signal transceiving on 3 channels. Thus, in the present invention, for sub-frame 0, its carrier dual function time slot is fixedly allocated to the CCO node for transmitting the central beacon signal, whereas since the central beacon signal needs to be repeatedly transmitted on the a/B/C three phases,

therefore, additional provisions are made for subframe 0: as shown in fig. 6, if the length of the carrier dual function timeslot is T, the first 2T-length timeslot of the CSMA timeslot area subsequent thereto only allows the CCO to transmit the central beacon signal.

(3) On the carrier side, except that the CCO needs to transmit and receive signals in three phases in turn, other nodes only need to be fixed on a phase channel for signal transmission and reception. Therefore, in the present invention, when the CCO performs signal reception in the CSMA slot region, it is specified that the adjustment of the reception phase is performed according to the number of the subframe, where the remainder of k modulo 3 is 0, 1, and 2, when the number of the subframe is k, the corresponding reception phases are phase a, phase B, and phase C in this order. Therefore, if a node needs to transmit a signal to the CCO in the CSMA slot region, the CSMA slot region of a subframe in which the reception phase of the CCO is the same as the self phase is selected for signal transmission based on the self phase.

(4) For carrier subframe N (1 ≦ N ≦ N), the usage rule of carrier dual-function timeslot is: if the node with the short address n is a proxy node (PCO) on the carrier side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave Station (STA), the time slot is fixedly allocated to the node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; and if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to transmit any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists.

Preferably, the specific length of the carrier dual function timeslot is equal to the transmission length of the beacon signal when the length of the signaling content in the frame payload signal reaches a prescribed upper limit for the timeslot structure of the new beacon period on the carrier channel.

Preferably, the method allocates the usage right to the time slot structure of the beacon period on the wireless channel according to the preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, and includes:

aiming at the time slot structure of a beacon period on a wireless channel, a network node with a short address of n has priority use right on the wireless dual-function time slot of a subframe n;

for wireless subframe 0, the wireless dual-function time slot is fixedly allocated to the CCO node and used for transmitting a central beacon signal;

for a wireless subframe n, if a node with a short address n is a proxy node PCO on a wireless side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

Preferably, wherein the specific length of the wireless dual function timeslot is equal to the transmission length of the beacon signal when the beacon signal signaling content length reaches a prescribed upper limit for the timeslot structure of the new beacon period on the wireless channel.

In the invention, in a channel access mechanism based on a beacon period, aiming at a beacon period time slot structure on a wireless channel, a pre-allocation use mechanism similar to a carrier direction is adopted for a wireless dual-function time slot of each subframe, namely, a network with a short address of n has a priority use right for the wireless dual-function time slot of the subframe n. The specific rule is as follows:

(1) The specific length of the wireless dual-function time slot is equal to the sending length of the beacon signal when the length of the signaling content of the beacon signal reaches the specified upper limit.

(2) The wireless network does not have the problem of channel transmission of multiple phases of the carrier network, so for the subframe 0, the wireless dual-function time slot is fixedly allocated to the CCO node for transmitting the central beacon signal.

(3) For a wireless subframe N (N is more than or equal to 1 and less than or equal to N), the usage rule of the wireless dual-function time slot is as follows: if the node with the short address n is a proxy node (PCO) on the wireless side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave Station (STA), the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; and if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to transmit any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists.

Preferably, the method minimizes the length of the signaling content in the beacon signal by using the following three message formats of the proxy node, including:

first agent node message format: beacon entry head + proxy node message number + number of proxy nodes + full list of proxy nodes; second agent node message format: beacon entry head + proxy node message number; third agent node message format: the method comprises the steps that a beacon entry head, a proxy node message number, the number of newly-added proxy nodes, a newly-added proxy node list, the number of newly-subtracted proxy nodes and a newly-subtracted proxy node list are added;

wherein the beacon entry header is used to identify the type of beacon message; the proxy node message number is used for identifying the time sequence of the message content; in the operation process of the network, in the idle period of the network service, the CCO node uses the message format of the first proxy node and carries the short addresses of all the proxy nodes in the central beacon signal; during periods of high network traffic load, the CCO node uses either the second proxy node message format or the third proxy node message format to minimize the signaling content length in the beacon signal.

Preferably, wherein the method further comprises:

if the agent node message adopts the first agent node message format and the message number is higher than the message number kept by the node after the node receives the beacon signal, updating the agent node information; if the message format is the second agent node message format and the message number is equal to the message number kept by the second agent node, the change is not needed; if the message format is the third agent node message format and the message number is only 1 greater than the message number kept by the third agent node message format, updating the agent node list according to the content of the message number; if an agent node message is received, wherein the message number of the agent node message is only greater than or equal to 2 than the message number kept by the agent node message, and the format of the agent node message is the second agent node message format or the third agent node message format, a request is sent to the agent node of the agent node in the CSMA time slot area, the agent node is required to independently send a proxy node list with the latest number to the agent node, and after the agent node receives the request, the agent node sends the proxy node list by using the first agent node message format in the next beacon period.

Due to the simplification of the time slot structure of the beacon period, the content of the signaling description in the beacon signal and the content related to the beacon signal are also greatly reduced, and only the following parameters and contents are included:

1) The length of the numerical value of N is 12 bit;

2) The number of beacon periods is 32 bits in length;

3) Network runtime (NTB), length 40 bit;

4) Proxy node message: since the proxy node list occupies the highest proportion of the beacon signaling content, in order to minimize the signaling content length, the first proxy node message format (format 1), the second proxy node message format (format 2), and the third proxy node message format (format 3) are employed as shown in (a), (b), and (c) of fig. 7. Wherein the beacon entry header is used to identify the type of beacon message; the message number of the proxy node is used to identify the time sequence of the message content, i.e. if the network produces the 1 st group of proxy nodes, the message number is 0, and then if the list of proxy nodes changes, i.e. new proxy nodes or primary proxy nodes decrease, the message number will be +1 (note: cycle is 0 after 255), while if the list of proxy nodes does not change, the message number will remain unchanged. In the operation process of the network, in the idle period of the network service, the CCO can use the proxy node message format 1, and the central beacon signal carries the short addresses of all proxy nodes; during periods of high network traffic load, the CCO may use format 2 or format 3, thereby minimizing the content length of the beacon signaling. If there are 100 proxy nodes in the network, the length of the message 1 is 153 bytes, and if there is no change in the proxy nodes, the length of the message 2 is only 2 bytes, and if there are 4 new proxy nodes and 4 reduced proxy nodes, the length of the message 3 is only 16 bytes.

The network of the invention is mainly applied to a power grid system, and the equipment nodes of the network are generally not subjected to position movement in the network operation process, so the network topology condition is relatively stable, and after the network agent node set is determined, the change or slow change does not occur in most of time, so the CCO does not need to transmit the agent node full list in the central beacon in each beacon period, and only needs to inform the network nodes of the changed agent node information with less quantity, thereby greatly saving the length of the signaling content on the premise of carrying the same signaling content and not influencing the information transmission correctness, and further reducing the channel overhead of the network beacon signals.

The invention also relates to the updating of the agent node information by the node based on the agent node message number, so as to further ensure the transmission accuracy of the agent node information. If one node receives the beacon signal, if the proxy node message in the beacon signal adopts a format 1 and the message number is higher than the message number kept by the node, updating the proxy node information; if the message number is in the format 2 and is equal to the message number kept by the proxy node, the proxy node list is not changed, and the proxy node list does not need to be changed; if the format is 3 and the message number is only 1 greater than the message number kept by the user, updating the proxy node list according to the content of the message number; and if a proxy node message with a message number which is more than or equal to 2 and the format of 2 or 3 is received, the proxy node message is considered to lose the latest proxy node list, so that a request can be sent to the proxy node of the proxy node in the CSMA time slot region, the proxy node is required to send the latest proxy node list to the proxy node of the proxy node, and the proxy node uses the format 1 to send the proxy node list in the next beacon period after receiving the request.

Preferably, wherein the method further comprises:

the CSMA time slot area of the subframe with the number of n only allows the node with the short address of n and the 1-hop neighbor node to use, if the node with the number of n does not access the network, the substitute is a CCO node; the 1-hop neighbor node monitors a synchronous signal head from the starting time position of the subframe, if the synchronization is successful, a subsequent signal is received, and after the signal reception is completed, the remaining time slot resources of the subframe are CSMA time slot areas; if the synchronization fails, the priority node of the whole subframe does not send signals on the dual-purpose time slot of the beacon period, except the length of the synchronization head signal, the rest time slot resources of the subframe are CSMA time slot areas; where a 1-hop neighbor node is a node that is capable of correctly receiving signals transmitted on the dual-function slot of the sub-frame.

In the invention, in order to further reduce the collision probability of signal transmission of the carrier wave and the wireless CSMA time slot area, the following same provisions are added for two channels:

1) The CSMA slot area of the subframe with the number n only allows the node with the short address n and the 1-hop neighbor node to use, and other network nodes do not allow the use. Wherein if the node is not networked, the substitute is a CCO node. Here, the 1-hop neighbor node refers to a node that can correctly receive a signal transmitted on the dual-use time slot of the subframe.

2) The neighbor nodes monitor the synchronous signal head from the initial time position of the subframe, if the synchronization is successful, the subsequent signals are received, and after the signal reception is completed, the residual time slot resources of the subframe are CSMA time slot areas; and if the synchronization fails, the priority node of the whole subframe does not send a signal on the dual-purpose time slot of the beacon period, except the length of the synchronization head signal, the rest time slot resources of the subframe are CSMA time slot areas.

The invention provides a set of novel channel access protocol for a dual-mode communication network, and the core idea is to refer to a beacon system in the existing high-speed carrier communication standard, but redesign the original super-frame time slot structure, reduce the channel overhead and meet the ordered channel access requirement of the dual-mode node with higher efficiency. Theoretical analysis shows that the new channel access protocol inherits some mature design concepts of the existing high-speed carrier communication standard, but the protocol content is simple, but the robustness is strong, and the stable operation of the whole network can be maintained under the complex channel environment.

The novel time slot structure provided by the invention has a simple structure, and simultaneously provides an optimized transmission scheme for information transmission of the proxy node list with the highest content length in the beacon information, so that the signaling content length of the beacon signal can be greatly reduced, and the channel overhead is reduced; meanwhile, a pre-allocation mechanism is adopted for partial time slot resources, the ordered conflict-free transmission requirements of signals needing to be periodically transmitted of each network access node are better guaranteed, meanwhile, the range of the competitive access node of the CSMA time slot area of each subframe is limited according to a local topological structure, channel competitive access points of the nodes in the whole network are dispersed, the channel collision probability in the process is effectively reduced, and therefore the comprehensive communication performance of the whole network is optimized.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (9)

1. A channel access method based on a dual-mode network is characterized by comprising the following steps:

before a network runs, a concentrator CCO node acquires a node MAC address list based on a white list mechanism, so that a dual-mode node in the MAC address list is accessed to the network when the CCO node runs in the network;

the identity of each dual-mode node in the network is identified through a short address; the short address of the CCO node defaults to 0, when slave nodes on the MAC address lists of other nodes access the network, the CCO node allocates a short address for the slave nodes, and the value range is [1, N ];

according to the short address of the dual-mode network node, respectively allocating the use rights to the time slot structures of the beacon periods on the carrier channel and the wireless channel according to a preset allocation use mechanism, so as to transmit signals according to the allocation of the use rights;

the beacon period comprises N +1 sub-frames, N is the number of the dual-mode nodes in the MAC address list, the time slot structure of each sub-frame is consistent, and the time slot structure of each sub-frame comprises a dual-function time slot and a CSMA time slot area.

2. The method of claim 1, wherein the method allocates the usage right to the time slot structure of the beacon period on the carrier channel according to a preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, comprising:

aiming at a time slot structure of a new beacon period on a carrier channel, a network node with a short address of n has priority use right on a carrier dual-function time slot of a subframe n;

for carrier subframe 0, the carrier dual-function time slot is fixedly allocated to the CCO node and used for transmitting the central beacon signal, the length of the carrier dual-function time slot is set to be T, and the time slot with the length of the first 2T of the subsequent CSMA time slot region only allows the CCO to transmit the central beacon signal;

for a carrier subframe n, if a node with a short address of n is a proxy node PCO on the carrier side, the time slot is fixedly allocated to the node n for the node n to send a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

3. The method of claim 2, further comprising:

when a CCO node receives signals in a CSMA time slot area, the receiving phase is adjusted according to the number of a subframe, wherein the number of the subframe is k, when the remainder of dividing k by module 3 is 0, 1 and 2, the corresponding receiving phase is an A phase, a B phase and a C phase in sequence, and when the node sends signals to the CCO node in the CSMA time slot area, the receiving phase of the CCO node and the CSMA time slot area of the subframe with the same phase as the self phase are selected to send the signals based on the self phase.

4. A method according to claim 2, characterized in that the specific length of the carrier dual function timeslot is equal to the transmission length of the beacon signal when the length of the signalling content in the frame payload signal reaches a prescribed upper limit, for the timeslot structure of the new beacon period on the carrier channel.

5. The method according to claim 1, wherein the method allocates the usage right to the time slot structure of the beacon period on the wireless channel according to the preset allocation usage mechanism according to the short address of the dual-mode network node, so as to transmit the signal according to the allocation of the usage right, comprising:

aiming at the time slot structure of a beacon period on a wireless channel, a network node with a short address of n has priority use right on the wireless dual-function time slot of a subframe n;

for wireless subframe 0, the wireless dual-function time slot is fixedly allocated to the CCO node and used for transmitting a central beacon signal;

for a wireless subframe n, if a node with a short address n is a proxy node PCO on a wireless side, the time slot is fixedly allocated to the node n for sending a proxy beacon signal; if the node is a slave station STA, the time slot is fixedly allocated to a node n, so that the node can autonomously select to transmit any type of signals according to the service requirement of the node, and the node is idle when no service exists; if the node is not accessed to the network, the time slot is fixedly allocated to the CCO, so that the CCO can autonomously select to send any type of signals according to the service requirement of the CCO, and the CCO is idle when no service exists; n is more than or equal to 1 and less than or equal to N.

6. The method of claim 5, wherein the specific length of the wireless dual function slot is equal to the transmission length of the beacon signal when the length of the beacon signal signaling content reaches a prescribed upper limit, for the slot structure of the new beacon period on the wireless channel.

7. The method of claim 1, wherein the method minimizes signaling content length in beacon signals using three proxy message formats, including:

first proxy node message format: beacon entry head + proxy node message number + number of proxy nodes + full list of proxy nodes; second agent node message format: beacon entry header + proxy node message number; third agent node message format: the method comprises the steps that a beacon entry head, a proxy node message number, the number of newly-added proxy nodes, a newly-added proxy node list, the number of newly-subtracted proxy nodes and a newly-subtracted proxy node list are added;

wherein the beacon entry header is used to identify the type of beacon message; the proxy node message number is used for identifying the time sequence of the message content; in the operation process of the network, in the idle period of the network service, the CCO node uses the message format of the first proxy node and carries the short addresses of all the proxy nodes in the central beacon signal; during periods of high network traffic load, the CCO node uses either the second proxy node message format or the third proxy node message format to minimize the signaling content length in the beacon signal.

8. The method of claim 7, further comprising:

if the agent node message adopts the first agent node message format and the message number is higher than the message number kept by the node after the node receives the beacon signal, updating the agent node information; if the message format is the second agent node message format and the message number is equal to the message number kept by the second agent node, the change is not needed; if the message format is the third agent node message format and the message number is only 1 greater than the message number kept by the third agent node message format, updating the agent node list according to the content of the message number; if an agent node message is received, the message number of which is only more than or equal to 2 than the message number of the agent node message and the format of which is the second agent node message format or the third agent node message format, the agent node sends a request to the agent node of the agent node in the CSMA time slot area, the agent node is required to send a latest numbered agent node list to the agent node of the agent node, and after the agent node receives the request, the agent node sends the agent node list by using the first agent node message format in the next beacon period.

9. The method of claim 1, further comprising:

the CSMA time slot area of the subframe with the number of n only allows the node with the short address of n and the 1-hop neighbor node to use, if the node with the number of n does not access the network, the substitute is a CCO node; the 1-hop neighbor node monitors a synchronous signal head from the starting time position of the subframe, if the synchronization is successful, a subsequent signal is received, and after the signal reception is completed, the remaining time slot resources of the subframe are CSMA time slot areas; if the synchronization fails, the priority node of the whole subframe is considered not to send signals on the dual-purpose time slot of the beacon period, and except the length of the synchronization head signal, the rest time slot resources of the subframe are CSMA time slot areas; where a 1-hop neighbor node is a node that is capable of correctly receiving signals transmitted on a dual function slot of the subframe.

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