CN113950140B - Clock synchronization method and system for low-voltage distribution network Internet of things - Google Patents
Clock synchronization method and system for low-voltage distribution network Internet of things Download PDFInfo
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- CN113950140B CN113950140B CN202111204147.9A CN202111204147A CN113950140B CN 113950140 B CN113950140 B CN 113950140B CN 202111204147 A CN202111204147 A CN 202111204147A CN 113950140 B CN113950140 B CN 113950140B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/04—Wireless resource allocation
- H04W72/044—Wireless resource allocation based on the type of the allocated resource
- H04W72/0453—Resources in frequency domain, e.g. a carrier in FDMA
Abstract
The invention relates to the technical field of Internet of things communication and discloses a clock synchronization method and a clock synchronization system for a low-voltage distribution network Internet of things.
Description
Technical Field
The invention relates to the technical field of Internet of things communication, in particular to a clock synchronization method and system for a low-voltage distribution network Internet of things.
Background
With the continuous development of power grid construction, the power line carrier technology is used as a main communication means of a low-voltage distribution network, the prior art only supports metering services, cannot meet various requirements of intelligent operation and maintenance, system operation, power market, intelligent scheduling, user side interaction and the like, the main power line carrier communication mode is difficult to consider the defects of a platform area and user family internal services, the traditional narrow-band carrier communication is mainly used for automatic meter reading services, the advantages of wide carrier communication distribution and low cost cannot be exerted, the power line carrier communication is used as the communication mode with the most wide coverage area in the power system communication along with the construction of the ubiquitous power internet of things, the power line carrier communication is also used as the basic communication means in the power system, the important role can be played in the multi-service bearing technology in the low-voltage distribution network, the clock synchronization is an important ring in the construction of the low-voltage distribution network internet of things, the clock synchronization is the basis of service expansion, and the clock synchronization method in the prior art is realized mostly based on the wireless transmission technology and single-frequency band carrier communication.
At present, the Chinese patent with the grant publication number of CN 106888503A discloses a time calibration method of a radio and television spectrum ultra-narrow band Internet of things, which is applied to a mobile terminal and comprises the following steps: transmitting an uplink calibration signal comprising first time information to the base station through a pre-established broadcast and television frequency spectrum ultra-narrow band communication system; monitoring all frequency bands of a broadcast and television spectrum ultra-narrow band communication system, and acquiring a downlink calibration signal which is transmitted by a base station through the broadcast and television spectrum ultra-narrow band communication system and comprises second time information; according to the second time information, adjusting the clock of the controller of the mobile terminal so as to synchronize the time of the mobile terminal and the time of the base station; repeating the steps until the time of the uplink process and the time of the downlink process of the base station and the mobile terminal are kept synchronous.
The above prior art solutions have the following drawbacks: the frequency band resources are used improperly, time is wasted for monitoring all frequency bands, and inaccurate signal transmission is easy to cause; meanwhile, when uplink and downlink time information is synchronized, the delay of signal transmission is not considered, so that clock synchronization is inaccurate.
Disclosure of Invention
The invention provides a clock synchronization method and system for a low-voltage distribution network Internet of things, which are used for solving the technical problems of inaccurate signal transmission and inaccurate clock synchronization.
In view of this, a first aspect of the present invention provides a clock synchronization method for an internet of things of a low-voltage distribution network, implemented based on two power line carrier communication devices, the two power line carrier communication devices being respectively installed on a transformer side and a user side, the power line carrier communication device installed on the transformer side being defined as a first communication device, the first communication device being used as a clock reference, the power line carrier communication device installed on the user side being defined as a second communication device, the method comprising the steps of:
step one, establishing a carrier communication channel between the first communication device and the second communication device, and taking a full frequency band as a carrier frequency band of the carrier communication channel;
dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively distributing a plurality of sub-carrier channels for each sub-frequency band according to a preset distribution rule;
step three, the first communication device and the second communication device are both provided with oscillation timers, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals consist of subcarrier signals of a plurality of different frequency sub-bands, each subcarrier signal carries a clock signal, and the clock signals carried by each subcarrier signal are consistent;
step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to obtain the receiving lag time of each subcarrier signal;
judging whether the receiving delay time of each subcarrier signal exceeds the timing period of a half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving delay time;
step six, acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with a received clock signal, and if not, updating the clock information into the compensated clock signal;
and step seven, performing electro-optical conversion on the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
Preferably, a plurality of subcarrier channels are respectively allocated to each subband by adopting quantum coding and genetic algorithm.
Preferably, the timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and larger than the average frequency of the minimum frequency band in the full frequency band.
Preferably, the method further comprises:
and establishing a wireless communication connection relation between the first communication device and the second communication device, generating a fault early warning signal if the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device based on the wireless communication connection relation so as to alarm.
Preferably, the method further comprises:
and when detecting that the carrier communication channel is distorted, re-executing the step two.
Preferably, the method further comprises:
obtaining a topological connection relation of a platform region, wherein the topological connection relation of the platform region comprises a transformer and each user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on a power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by a transformer;
based on the topological connection relation of the transformer area, acquiring the time-varying periods of the number of the user equipment accessed by the transformer through the historical marketing data, and dividing the time-varying periods of the number of the user equipment into idle time periods and busy time periods according to the preset values of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy time periods is more than the number of the user equipment accessed in the idle time periods;
and executing the second step in the idle period.
In a second aspect, the present invention further provides a clock synchronization system for an internet of things of a low voltage distribution network, implemented based on two power line carrier communication devices, where the two power line carrier communication devices are respectively installed on a transformer side and a user side, the power line carrier communication device installed on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device installed on the user side is defined as a second communication device, and the system includes:
the carrier communication module is used for establishing a carrier communication channel between the first communication device and the second communication device, and taking a full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing the full frequency band to obtain a plurality of different sub-frequency bands and also is used for respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule;
the first communication device and the second communication device are both provided with oscillation timers, and the oscillation timers are used for providing timing periods; the oscillation timer of the first communication device is configured to send a carrier signal to the second communication device when the timing period returns to zero, where the carrier signal is composed of a plurality of sub-carrier signals in different sub-frequency bands, each of the sub-carrier signals carries a clock signal, and the clock signals carried by each of the sub-carrier signals are kept consistent;
the second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when the carrier signal is received, and obtaining the receiving lag time of each subcarrier signal through the difference processing between the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving delay time of each subcarrier signal exceeds the timing period of the half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, the corresponding clock signal is compensated by using the receiving delay time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with a received clock signal, and updating the clock information into the compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronization transmission module is used for carrying out electro-optical conversion on the updated clock information into optical signals and outputting the optical signals to the lower-layer Internet of things equipment terminal through optical fibers so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
Preferably, the system further comprises:
the wireless transmission module is used for establishing a wireless communication connection relation between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device for warning based on the wireless communication connection relation.
Preferably, the system further comprises: and the carrier allocation module is used for re-dividing the full frequency band to obtain a plurality of different sub-frequency bands when the carrier communication channel is detected to be distorted, and respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule.
Preferably, the system further comprises:
the topology acquisition module is used for acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and all user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the electric power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by the transformer;
the period dividing module is used for acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data based on the topological connection relation of the transformer area, and dividing the time-varying period of the number of the user equipment into an idle period and a busy period according to a preset value of the number of the user equipment, wherein the number of the transformer accessed by the transformer in the busy period is more than the number of the user equipment in the idle period;
the frequency band allocation module is further configured to divide the full frequency band in the idle period to obtain a plurality of different frequency sub-bands, and further configured to allocate a plurality of subcarrier channels to each frequency sub-band in the idle period according to a preset allocation rule.
From the above technical scheme, the invention has the following advantages:
according to the invention, a full frequency band is used as a carrier frequency band of a carrier communication channel between a transformer and a user side, a plurality of sub-carrier channels are respectively allocated to each sub-frequency band according to a preset allocation rule, the frequency band with the better carrier frequency channel can be selected, the accuracy of carrier communication information transmission can be improved, after a first communication device sends a carrier signal carrying a clock signal to a second communication device, the second communication device obtains the corresponding receiving moment of each sub-carrier signal, determines the receiving delay time according to the timing period of an oscillation timer of the second communication device, compensates the corresponding clock signal by using the receiving delay time if the receiving delay time exceeds the timing period of a half oscillation timer, and also judges whether the clock information of the second communication device is matched with the received clock signal, if the clock information is not matched with the received clock signal, the compensated clock signal is used as the clock information of the second communication device, and the clock information is transmitted to lower-layer equipment through an optical fiber signal in an optical signal mode to complete clock synchronization, so that the influence on clock synchronization can be furthest reduced, and the clock synchronization accuracy is improved.
Drawings
Fig. 1 is a schematic structural diagram of a power line carrier communication device according to an embodiment of the present invention;
fig. 2 is a flowchart of a clock synchronization method for the internet of things of the low-voltage distribution network according to an embodiment of the present invention.
Detailed Description
In order to make the present invention better understood by those skilled in the art, the following description will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The clock synchronization method for the low-voltage distribution network Internet of things is realized based on two power line carrier communication devices, and as shown in fig. 1, the two power line carrier communication devices are respectively arranged on a transformer side and a user side, the power line carrier communication device arranged on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device arranged on the user side is defined as a second communication device.
As shown in fig. 2, the method comprises the following steps:
step one, a carrier communication channel is established between a first communication device and a second communication device, and a full frequency band is used as a carrier frequency band of the carrier communication channel.
The full-band carrier communication can better exert carrier performance and support more power services, and can meet the communication requirements of a platform area and user side equipment and also meet the requirements of layered power line carrier communication in the construction of the actual Internet of things.
Dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively distributing a plurality of sub-carrier channels for each sub-frequency band according to a preset distribution rule.
In a specific embodiment, a plurality of subcarrier channels are respectively allocated to each subband by adopting quantum coding and genetic algorithm.
The quantum coding and genetic algorithm is the prior art, and can solve the problem of subcarrier allocation during multiple access by utilizing the quantum coding and genetic algorithm, ensure that communication after a plurality of power equipment are accessed into a transformer is kept smooth, and realize the accuracy of clock synchronization.
The number of the subcarrier signals allocated to each frequency sub-band is three, taking power frequency carrier communication, intermediate frequency narrowband and high frequency narrowband as examples, under the condition that the carrier communication channel environment is stable, the arrival time of the subcarrier signals of different frequency bands should be consistent, and the arrival time of the subcarriers has a certain interval (but small interval) in consideration of the fluctuation of the actual environment.
Because the carrier frequency bands used as the carrier communication channels are different in frequency bands of the subcarriers, the subcarrier channels can be allocated to select the frequency bands with better carrier channels, and the accuracy of carrier communication information transmission can be improved.
And step three, the first communication device and the second communication device are both provided with oscillation timers, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals consist of a plurality of subcarrier signals with different frequency sub-bands, each subcarrier signal carries a clock signal, and the clock signals carried by each subcarrier signal are kept consistent.
The timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and larger than the average frequency of the minimum frequency band in the full frequency band, and the frequency of the timing period is located in the range of the subcarrier frequency band, so that the delay difference of carrier signal transmission can be accurately measured.
Wherein the clock signal is obtained when the carrier signal is transmitted based on a system clock of the first communication device.
And step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to acquire the receiving lag time of each subcarrier signal.
In a specific embodiment, after the difference between the timing period of the oscillation timer and the receiving time corresponding to each subcarrier signal is obtained, the average value of the sum of all the differences is taken as the receiving delay time, so as to improve the accuracy of calculation.
Wherein the carrier communication receiving circuit in the second communication device is provided with a function of recording the reception time at the same time when the carrier signal is received. Meanwhile, the cycle frequencies of the oscillation timers of the first communication device and the second communication device are consistent.
And fifthly, judging whether the receiving delay time of each subcarrier signal exceeds the timing period of the half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by utilizing the receiving delay time.
Step six, based on the system clock of the second communication device, obtaining the corresponding clock information, judging whether the clock information is matched with the received clock signal, if not, updating the clock information into the compensated clock signal.
The clock information is system clock information of the second communication device, and if the clock information does not match with the received clock signal (the error is greater than a predetermined threshold value), it is indicated that the system clock of the second communication device is not synchronous, and the clock signal needs to be overlaid on the clock information.
If the clock information matches the received clock signal, the original clock information can be used.
And step seven, performing electro-optical conversion on the updated clock information into optical signals, and outputting the optical signals to the lower-layer Internet of things equipment terminal through optical fibers so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
The clock information is an electric signal, the correct clock information is converted into an optical signal to be transmitted to the equipment through the optical fiber, and the optical fiber transmission delay is small and can be ignored, so that the accuracy of clock synchronization is improved.
In a specific embodiment, the method further comprises:
and establishing a wireless communication connection relation between the first communication device and the second communication device, generating a fault early warning signal if the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device based on the wireless communication connection relation so as to alarm.
When the first communication device transmits the carrier communication signal, the first communication device transmits the radio signal at the same time, and the radio signal is delayed greatly and is not normally used for clock synchronization, but when the second communication device receives only the radio signal, it is determined that the carrier communication is faulty and an alarm is transmitted to the first communication device.
In another possible embodiment, when the carrier communication fails, a wireless signal is sent by the first communication device for clock synchronization, and because the wireless signal has a larger delay, the first communication device and the second communication device are both provided with GPS positioning modules, the GPS positioning modules are used for ranging, the measured distance is used for calculating and correcting the delay of the signal transmitted by the wireless transmission module, and the delay is corrected according to the positive correlation relationship between the distance and the delay.
The embodiment uses the timing period of the oscillation timer to record the signal transmission delay, ensures the accuracy of the clock signal, and can ensure the clock synchronism through wireless signal transmission under the condition of failure of carrier communication.
In a specific embodiment, the method further comprises:
and when the carrier communication channel is detected to be distorted, the second step is re-executed.
It should be noted that, when the factors such as external environment interference and equipment switching all cause the change of the carrier communication channel environment, the channel gain changes along with the change, and the delay of signal transmission also changes, so that the carrier communication channel generates signal distortion, that is, when the frequency band of the subcarrier is not the optimal frequency band, the subcarrier channel needs to be reassigned, and then clock synchronization is performed again, thereby reducing errors.
When the carrier communication channel environment is kept stable, the clock synchronization is carried out at fixed time, and the clock synchronization operation is carried out again after a certain number of periods are reached according to the number of the timing periods of the oscillation timer.
In a specific embodiment, the method further comprises:
obtaining a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and each user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on the electric power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by the transformer;
based on a topological connection relation of a platform area, acquiring a time-varying period of the number of user equipment accessed by a transformer through historical marketing data, and dividing the time-varying period of the number of user equipment into an idle period and a busy period according to a preset value of the number of user equipment, wherein the number of the user equipment accessed by the transformer in the busy period is more than the number of the user equipment accessed in the idle period;
and executing the second step in the idle period.
It should be noted that, the number of the transformer access electric devices changes with time and has a certain period rule, the idle period and the busy period can be determined according to the device access and access period, and the number of the user devices accessed by the transformer in the busy period is greater than the number of the user devices accessed in the idle period, so that the idle period can be preferentially selected and the busy period can be avoided when the transformer is allocated, thereby improving the subcarrier allocation speed and being beneficial to establishing a stable carrier communication channel with high quality.
The invention provides a clock synchronization method of a low-voltage distribution network Internet of things, which is characterized in that a full frequency band is used as a carrier frequency band of a carrier communication channel between a transformer and a user side, a plurality of sub-carrier channels are respectively distributed for each sub-frequency band according to a preset distribution rule, the frequency band with the better carrier frequency channel can be selected, the accuracy of carrier communication information transmission can be improved, after a first communication device sends carrier signals carrying clock signals to a second communication device, the second communication device obtains the receiving moment corresponding to each sub-carrier signal, the receiving lag time is determined according to the timing period of an oscillation timer of the second communication device, if the receiving lag time exceeds the timing period of a half oscillation timer, the corresponding clock signals are compensated by utilizing the receiving lag time, if the clock information of the second communication device is not matched with the received clock signals, the compensated clock signals are used as the clock information of the second communication device, the clock information is transmitted to lower equipment through an optical fiber in an optical signal mode to complete clock synchronization by using the optical fiber, and therefore the influence of environmental interference on clock synchronization can be furthest reduced, and the clock synchronization accuracy is improved.
The invention also provides a clock synchronization system of the low-voltage distribution network Internet of things, which is realized based on two power line carrier communication devices, as shown in fig. 1, wherein the two power line carrier communication devices are respectively arranged on a transformer side and a user side, the power line carrier communication device arranged on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, the power line carrier communication device arranged on the user side is defined as a second communication device, and the system comprises:
the carrier communication module is used for establishing a carrier communication channel between the first communication device and the second communication device, and taking the full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing the full frequency band to obtain a plurality of different sub-frequency bands and also is used for respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule;
wherein, quantum coding and genetic algorithm are adopted to respectively allocate a plurality of subcarrier channels for each frequency sub-band.
The first communication device and the second communication device are both provided with oscillation timers, and the oscillation timers are used for providing timing periods; the first communication device is used for transmitting carrier signals to the second communication device when the timing period of the first communication device returns to zero, wherein the carrier signals consist of a plurality of subcarrier signals with different frequency sub-bands, each subcarrier signal carries a clock signal, and the clock signals carried by each subcarrier signal are consistent;
the timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and larger than the average frequency of the minimum frequency band in the full frequency band.
The second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when the carrier signal is received, and obtaining the receiving lag time of each subcarrier signal through the difference processing between the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving delay time of each subcarrier signal exceeds the timing period of the half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, the corresponding clock signal is compensated by the receiving delay time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal, and updating the clock information into a compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronous transmission module is used for carrying out electro-optical conversion on the updated clock information into optical signals and outputting the optical signals to the lower-layer Internet of things equipment terminal through optical fibers so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
In a specific embodiment, the system further comprises:
the wireless transmission module is used for establishing a wireless communication connection relation between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device based on the wireless communication connection relationship so as to warn.
In a specific embodiment, the system further comprises: and the carrier allocation module is used for re-dividing the full frequency band to obtain a plurality of different sub-frequency bands when the carrier communication channel is detected to be distorted, and respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule.
In a specific embodiment, the system further comprises:
the topology acquisition module is used for acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and each user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the electric power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by the transformer;
the time period dividing module is used for acquiring the time-varying periods of the number of the user equipment accessed by the transformer through the historical marketing data based on the topological connection relation of the transformer area, and dividing the time-varying periods of the number of the user equipment into idle time periods and busy time periods according to the preset value of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy time periods is larger than that in the idle time periods;
the frequency band allocation module is also used for dividing the full frequency band in the idle period to obtain a plurality of different sub-frequency bands, and is also used for respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule in the idle period.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
In the several embodiments provided by the present invention, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of elements is merely a logical functional division, and there may be additional divisions of actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The method for synchronizing the clock of the Internet of things of low-voltage distribution network is realized based on two power line carrier communication devices, wherein the two power line carrier communication devices are respectively arranged on a transformer side and a user side, the power line carrier communication device arranged on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device arranged on the user side is defined as a second communication device, and the method is characterized by comprising the following steps:
step one, establishing a carrier communication channel between the first communication device and the second communication device, and taking a full frequency band as a carrier frequency band of the carrier communication channel;
dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively distributing a plurality of sub-carrier channels for each sub-frequency band according to a preset distribution rule;
step three, the first communication device and the second communication device are both provided with oscillation timers, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals consist of subcarrier signals of a plurality of different frequency sub-bands, each subcarrier signal carries a clock signal, and the clock signals carried by each subcarrier signal are consistent;
step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to obtain the receiving lag time of each subcarrier signal;
judging whether the receiving delay time of each subcarrier signal exceeds the timing period of a half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving delay time;
step six, acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with a received clock signal, and if not, updating the clock information into the compensated clock signal;
and step seven, performing electro-optical conversion on the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
2. The method for synchronizing the clock of the internet of things of the low-voltage distribution network according to claim 1, wherein a plurality of subcarrier channels are respectively allocated to each sub-band by adopting quantum coding and genetic algorithm.
3. The method for synchronizing the clock of the internet of things of the low-voltage distribution network according to claim 1, wherein the timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and larger than the average frequency of the minimum frequency band in the full frequency band.
4. The method for synchronizing the clock of the internet of things of the low-voltage distribution network according to claim 1, further comprising:
and establishing a wireless communication connection relation between the first communication device and the second communication device, generating a fault early warning signal if the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device based on the wireless communication connection relation so as to alarm.
5. The method for synchronizing the clock of the internet of things of the low-voltage distribution network according to claim 1, further comprising:
and when detecting that the carrier communication channel is distorted, re-executing the step two.
6. The method for synchronizing the clock of the internet of things of the low-voltage distribution network according to claim 1, further comprising:
obtaining a topological connection relation of a platform region, wherein the topological connection relation of the platform region comprises a transformer and each user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on a power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by a transformer;
based on the topological connection relation of the transformer area, acquiring the time-varying periods of the number of the user equipment accessed by the transformer through the historical marketing data, and dividing the time-varying periods of the number of the user equipment into idle time periods and busy time periods according to the preset values of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy time periods is more than the number of the user equipment accessed in the idle time periods;
and executing the second step in the idle period.
7. The utility model provides a low pressure distribution network thing networking clock synchronization system, is realized based on two power line carrier communication device, two power line carrier communication device installs respectively in transformer side and user side, install in the power line carrier communication device of transformer side defines as first communication device, first communication device is used for as the clock benchmark, install in the power line carrier communication device of user side defines as second communication device, its characterized in that, its system includes:
the carrier communication module is used for establishing a carrier communication channel between the first communication device and the second communication device, and taking a full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing the full frequency band to obtain a plurality of different sub-frequency bands and also is used for respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule;
the first communication device and the second communication device are both provided with oscillation timers, and the oscillation timers are used for providing timing periods; the oscillation timer of the first communication device is configured to send a carrier signal to the second communication device when the timing period returns to zero, where the carrier signal is composed of a plurality of sub-carrier signals in different sub-frequency bands, each of the sub-carrier signals carries a clock signal, and the clock signals carried by each of the sub-carrier signals are kept consistent;
the second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when the carrier signal is received, and obtaining the receiving lag time of each subcarrier signal through the difference processing between the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving delay time of each subcarrier signal exceeds the timing period of the half oscillation timer, and if the receiving delay time exceeds the timing period of the half oscillation timer, the corresponding clock signal is compensated by using the receiving delay time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with a received clock signal, and updating the clock information into the compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronization transmission module is used for carrying out electro-optical conversion on the updated clock information into optical signals and outputting the optical signals to the lower-layer Internet of things equipment terminal through optical fibers so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
8. The low voltage distribution network internet of things clock synchronization system of claim 7, further comprising:
the wireless transmission module is used for establishing a wireless communication connection relation between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device for warning based on the wireless communication connection relation.
9. The low voltage distribution network internet of things clock synchronization system of claim 7, further comprising: and the carrier allocation module is used for re-dividing the full frequency band to obtain a plurality of different sub-frequency bands when the carrier communication channel is detected to be distorted, and respectively allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule.
10. The low voltage distribution network internet of things clock synchronization system of claim 7, further comprising:
the topology acquisition module is used for acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and all user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the electric power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by the transformer;
the period dividing module is used for acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data based on the topological connection relation of the transformer area, and dividing the time-varying period of the number of the user equipment into an idle period and a busy period according to a preset value of the number of the user equipment, wherein the number of the transformer accessed by the transformer in the busy period is more than the number of the user equipment in the idle period;
the frequency band allocation module is further configured to divide the full frequency band in the idle period to obtain a plurality of different frequency sub-bands, and further configured to allocate a plurality of subcarrier channels to each frequency sub-band in the idle period according to a preset allocation rule.
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| CN101610108A (en) * | 2009-07-15 | 2009-12-23 | 电信科学技术第一研究所 | Improve the method for digital spread spectrum receiver carrier phase jitter and wave distortion |
| CN102694762A (en) * | 2011-03-25 | 2012-09-26 | 北京新岸线无线技术有限公司 | Method for realizing synchronization of carrier and sampling clock, and user site device |
| CN109547146A (en) * | 2019-01-14 | 2019-03-29 | 北京邮电大学 | A kind of Wireless clock synchronous method and device based on super broad band radio communication |
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| CN101610108A (en) * | 2009-07-15 | 2009-12-23 | 电信科学技术第一研究所 | Improve the method for digital spread spectrum receiver carrier phase jitter and wave distortion |
| CN102694762A (en) * | 2011-03-25 | 2012-09-26 | 北京新岸线无线技术有限公司 | Method for realizing synchronization of carrier and sampling clock, and user site device |
| CN109547146A (en) * | 2019-01-14 | 2019-03-29 | 北京邮电大学 | A kind of Wireless clock synchronous method and device based on super broad band radio communication |
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