Power equipment access method based on TDMA (Time Division Multiple Access)

Abstract

The invention discloses a power equipment access method based on TDMA (Time Division Multiple Access), which specifically comprises the following steps: in a power TDMA communication system, all time slots are divided into a synchronous time slot, an access time slot, a broadcast time slot, a downlink transmission time slot and an uplink transmission time slot according to functions, and a protection interval is reserved when the uplink time slot and the downlink time slot are switched. And the downlink transmission time slot and the uplink transmission time slot appear alternately, so that the transmission delay is reduced. In addition, the structure is suitable for an ad hoc network architecture, and the ad hoc network between devices can be realized. According to the TDMA-based power equipment access method provided by the invention, rapid access and networking of massive power equipment can be realized.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a method for accessing power equipment based on TDMA. Background Art

[0002] With the increasing maturity of wireless communication and mobile communication technologies and the growing demand for communication by people, the research in the field of wireless communication has become a hot topic in the industry, and new technologies emerge in an endless stream, bringing great convenience to human society. Among them, the wireless ad-hoc network (Ad-Hoc) has attracted the attention of various fields due to its flexible networking and rapid deployment characteristics.

[0003] The power wireless ad-hoc network is a wireless network topology structure based on the combination of power line communication and wireless communication technologies, and is used to implement smart grid and Internet of Things applications in the power system. It uses power lines and wireless signals as communication media, and realizes wireless communication and data transmission between nodes by installing intelligent power nodes and wireless devices on power lines. Nodes can directly communicate with each other through power line communication or wireless signals, or transmit data through relay nodes. This network topology structure has characteristics such as self-organization, self-healing, and self-adaptation, and can automatically establish and optimize network connections, providing reliable wireless data transmission and communication services.

[0004] The power wireless ad-hoc network is widely applied in the field of smart grid, including power equipment monitoring, power quality monitoring, remote meter reading, smart home, etc. It can realize the intelligent management and optimized control of the power system, improve the reliability, safety, and efficiency of the power grid, and provide a more convenient and intelligent power consumption experience for users. At the same time, by adding wireless communication, it can also expand the network coverage and provide a more flexible communication method to meet the requirements of different application scenarios.

[0005] There are more and more power sensors and collectors, and the amount of data uploaded by a single collector per day is very small. Therefore, the present invention proposes a method for accessing power equipment based on TDMA, and this structure is applicable to multi-frequency narrowband power scenarios and can support the access of a large number of power equipment. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for accessing power equipment based on TDMA to realize the self-networking of power-authorized discrete frequency points.

[0007] The technical solution for achieving the purpose of the present invention is: a method for accessing power equipment based on TDMA, and the smallest transmission structure is a superframe. According to functional division, a superframe is divided into a synchronization time slot, an access time slot, a broadcast time slot, a downlink transmission time slot, and an uplink transmission time slot.

[0008] Furthermore, this access method can work on different frequency points simultaneously, and the Time Division Multiple Access (TDMA) method is adopted for access on each frequency point.

[0009] Furthermore, the power wireless base station uses synchronous time slots to transmit set synchronous signals. The power wireless terminal searches for the power wireless base station and synchronizes with it in terms of time slots. By identifying the content of the synchronization word, the power wireless terminal enters the corresponding working states, including adaptive rate and fixed rate.

[0010] Furthermore, the access time slot is used for the access of the power wireless terminal. At this time, the power wireless base station is in the listening state, and the power wireless terminal is in the sending state. The power wireless terminals perform random access in the Time Slot ALOHA manner. The power wireless terminal confirms its access state through broadcasting time slots, and uses whether it is allocated a communication time slot as the criterion for whether to access. If the power wireless terminal fails to access successfully, it continues to perform random access in the ALOHA manner in the next subframe. If it fails to access successfully in multiple superframes, the power wireless terminal switches the communication frequency and communication parameters and conducts access attempts until it accesses the system.

[0011] Furthermore, the broadcast time slot is used for the transmission of broadcast information by the power wireless base station, including access response, time slot scheduling, and telemetry response.

[0012] Furthermore, the downlink transmission time slot is used for the downlink data link of the power wireless terminal. Since the number of power wireless terminals is greater than the set value, the downlink transmission time slots are distributed in a discrete form and appear alternately with the uplink transmission time slots to balance the data transmission delay.

[0013] Furthermore, the uplink transmission time slot is used for the power wireless base station to send remote control information, and can also be used to send time slot scheduling instructions when the number of time slot scheduling instructions is more than the set value.

[0014] Furthermore, when there are multiple services to be sent at the power wireless base station, the priority P is calculated according to the service waiting time and the upper limit of service delay i , which is expressed as:

[0015]

[0016] where t is the current waiting time of this service, and a represents the longest waiting time that this service can tolerate.

[0017] Compared with the prior art, the remarkable advantages of the present invention are as follows: it can support self-organizing network communication on multiple discrete frequency points simultaneously, has small communication delay, supports a large number of power access terminals, and has service fairness, and can ensure the communication quality when multiple services coexist. Description of the Drawings

[0018] Figure 1It is a schematic diagram of communication time slot division for the TDMA-based power equipment access method of the present invention.

[0019] Figure 2 It is a terminal processing flowchart for the TDMA-based power equipment access method of the present invention. Detailed implementation manners

[0020] The power wireless base station realizes multiple channels by deploying multiple narrowband communication chips in terms of hardware. Each channel adopts different frequencies or communication parameters. When initializing, the power wireless terminal can be configured with a certain valid frequency among the frequencies of multiple power wireless base stations and communication parameters. In this FDMA manner, the power wireless terminals can be divided into multiple groups according to communication frequencies. The communication frequency of the power wireless terminal can be dynamically configured through software. If a power wireless terminal initiates access multiple times without response, it can switch the communication frequency for access. Next, the access method within each frequency point and the corresponding spreading factor group is designed.

[0021] The communication for each frequency point adopts the TDMA method. According to functional division, a superframe can be divided into a synchronization time slot, an access time slot, a broadcast time slot, a downlink transmission time slot, and an uplink transmission time slot. Each frame is composed of multiple time slots. A guard interval is reserved when switching between the uplink frame and the downlink frame. The functions of various frames are as follows:

[0022] 1) Synchronization time slot: The synchronization time slot is used for the power wireless base station to transmit specific synchronization signals, facilitating the power wireless terminal to search for the power wireless base station and perform time slot synchronization with the power wireless base station. By identifying the content of the synchronization word, the power wireless terminal can work in corresponding states, such as adaptive rate, fixed rate, etc.

[0023] 2) Access time slot: It is used for the access of the power wireless terminal. At this time, the power wireless base station is in the listening state, and the power wireless terminal is in the sending state. The power wireless terminals perform random access in the time slot ALOHA manner. The power wireless terminal confirms its access status through the broadcast time slot (using whether it is allocated a communication time slot as the criterion for whether to access). If the power wireless terminal fails to access successfully, it continues to perform random access in the ALOHA manner in the next subframe. If it fails to access successfully in multiple superframes, the power wireless terminal switches the communication frequency and the corresponding spreading factor, and performs access attempts until it accesses the system.

[0024] 3) Broadcast time slots: Used for the transmission of broadcast information of the power wireless base station, including access response, time slot scheduling, and telemetry response. The access response is used to allocate communication time slots to devices that have successfully competed. Once a power wireless terminal is allocated a time slot, it will use the corresponding time slot within each superframe to send downlink data before receiving a new scheduling instruction. Time slot scheduling is used to adjust the communication time slots of power wireless terminals. After receiving this scheduling instruction, the power wireless terminal will send downlink data in the new time slot. The telemetry response is used for the power wireless base station to respond whether the downlink data was received in each time slot of the previous superframe by the power wireless terminal. The power wireless terminal can adaptively adjust the spreading factor and its corresponding frequency according to the response situation to achieve adaptive rate adjustment.

[0025] 4) Downlink transmission time slots: Used for the downlink data link of power wireless terminals. Since the number of power wireless terminals is large, the downlink transmission time slots are distributed in a discrete form and alternate with the uplink transmission time slots, which is beneficial to balancing the telemetry delay and the remote control delay. Each downlink transmission time slot contains multiple time slots. The minimum scheduling unit for the downlink data communication of power wireless terminals is a time slot. The power wireless base station can also allocate multiple time slots to a power wireless terminal within one superframe.

[0026] 5) Uplink transmission time slots: Mainly used for the power wireless base station to send remote control information. When there are many time slot scheduling instructions, it can also be used to send time slot scheduling instructions.

[0027] When there are multiple services to be sent at the power wireless base station, the priority P is calculated according to the service waiting time and the service delay upper limit i , expressed as:

[0028]

[0029] where t is the current waiting time of the service, and a represents the longest waiting time that the service can tolerate.

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Embodiment

[0032] The power wireless ad hoc network adopts the combination of FDMA and TDMA to achieve parallel control of power wireless terminals by power wireless base stations. Hardware-wise, the power wireless base station realizes multiple channels by deploying multiple narrowband communication chips. Each channel uses a different frequency or spreading factor. When initializing, the power wireless terminal can be configured with a valid frequency among those of multiple power wireless base stations and the corresponding spreading factor. Through this FDMA method, the power wireless terminals can be divided into multiple groups according to the communication frequency. The communication frequency of the power wireless terminal can be dynamically configured by software. If a power wireless terminal initiates access multiple times without response, it can switch the communication frequency for access. Next, the access method for each frequency point and the corresponding spreading factor group will be designed.

[0033] As Figure 1 shown, the communication for each frequency point adopts the TDMA method. According to the function division, a superframe can be divided into a synchronization time slot, an access time slot, a broadcast time slot, a downlink transmission time slot, and an uplink transmission time slot. A guard interval is reserved when switching between the uplink frame and the downlink frame. The functions of various time slots are as follows:

[0034] 1) Synchronization time slot: The synchronization time slot is used for the power wireless base station to transmit specific synchronization signals, facilitating the power wireless terminal to search for the power wireless base station and perform time slot synchronization with the power wireless base station. By identifying the content of the synchronization word, the power wireless terminal can operate in the corresponding state, such as adaptive rate, fixed rate, etc.

[0035] 2) Access time slot: It is used for the access of the power wireless terminal. At this time, the power wireless base station is in the listening state, and the power wireless terminal is in the transmitting state. The power wireless terminals perform random access in the time slot ALOHA mode. The power wireless terminal confirms its access status through the broadcast time slot (using whether it is assigned a communication time slot as the criterion for whether it has accessed successfully). If the power wireless terminal fails to access successfully, it will continue to perform random access in the ALOHA mode in the next subframe. If it fails to access successfully in multiple superframes, the power wireless terminal will switch the communication frequency and the corresponding spreading factor and perform access attempts until it accesses the system.

[0036] 3) Broadcast time slot: Used for the transmission of broadcast information of the power wireless base station, including access response, time slot scheduling, and telemetry response. The access response is used to allocate communication time slots to devices that have successfully competed. Once a power wireless terminal is allocated a time slot, it will use the corresponding time slot within each superframe to send downlink data before receiving a new scheduling instruction. Time slot scheduling is used to adjust the communication time slots of power wireless terminals. After receiving this scheduling instruction, the power wireless terminal will send downlink data in the new time slot. The telemetry response is used for the power wireless base station to respond whether the downlink data was received in each time slot of the previous superframe by the power wireless terminal. The power wireless terminal can adaptively adjust the spreading factor and its corresponding frequency according to the response situation to achieve adaptive rate adjustment.

[0037] 4) Downlink transmission time slot: Used for the downlink data link of power wireless terminals. Since the number of power wireless terminals is large, the downlink transmission time slots are distributed in a discrete form and alternate with the uplink transmission time slots, which is beneficial to balancing the telemetry delay and the remote control delay. Each downlink transmission time slot contains multiple time slots. The minimum scheduling unit for the downlink data communication of power wireless terminals is a time slot. The power wireless base station can also allocate multiple time slots to a power wireless terminal within a superframe.

[0038] 5) Uplink transmission time slot: Mainly used for the power wireless base station to send remote control information. When there are many time slot scheduling instructions, it can also be used to send time slot scheduling instructions.

[0039] The working process of the power wireless base station is relatively simple. After power-on, it only needs to set up each narrowband communication channel according to the configuration parameters, and then send data according to the superframe format. When a user access request is received, it allocates a communication time slot for it; when the time slot resources of this channel are insufficient, it rejects the access request of the power wireless terminal; to prevent the situation where the power wireless terminal changes the telemetry transmission channel and the power wireless base station does not receive relevant notifications, the power wireless base station will periodically check the occupancy of each current time slot. When a previously allocated time slot is not occupied for a long time, it will release the scheduling of this time slot and send the corresponding broadcast instruction.

[0040] The working process of the power wireless terminal is as Figure 2As shown, after power-on, the power wireless terminal operates according to pre-set parameters, including communication frequency, spreading factor, etc. When the synchronous time slot signal of the power wireless base station is detected, time slot synchronization is obtained, and the working mode is set according to the indication of the synchronization word of the power wireless base station. If the synchronous time slot of the power wireless base station is not detected for multiple times, the working parameters are switched to re-detect the synchronous time slot of the power wireless base station. Subsequently, an access request is sent in the access time slot in an ALOHA manner, and then the terminal listens in the broadcast time slot. When the corresponding response frame is detected, the uplink and downlink data transmission time slots are obtained, and then downlink data can be sent in the specified time slot. Subsequently, the terminal listens to the uplink transmission time slot and the broadcast time slot from the power wireless base station. When the power wireless terminal is in the adaptive rate mode, if the counter indicates that the communication rate needs to be switched, the parameters are re-set according to the indication of the counter and the synchronous time slot is listened to.

[0041] When there are multiple services to be sent at the power wireless base station, the priority P is calculated according to the service waiting time and the upper limit of service delay i , expressed as:

[0042]

[0043] Among them, t is the current waiting time of the service, and a represents the longest waiting time that the service can tolerate. For example, there are 2 services to be sent at the power wireless base station. The longest waiting time that service 1 can tolerate is 2s, and the longest waiting time that service 2 can tolerate is 4s. Both services have waited for 1s currently. Then, when the next transmission time slot arrives, service 1 is preferentially sent.

[0044] As described above, this is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A TDMA-based power equipment access method, characterized in that, the smallest transmission structure is a superframe. According to function division, a superframe is divided into a synchronization time slot, an access time slot, a broadcast time slot, a downlink transmission time slot, and an uplink transmission time slot.

2. The TDMA-based power equipment access method according to claim 1, characterized in that, this access method can work on different frequency points simultaneously, and the time division multiple access (TDMA) method is used for access on each frequency point.

3. The TDMA-based power equipment access method according to claim 1, characterized in that, the power wireless base station uses the synchronization time slot to transmit a set synchronization signal. The power wireless terminal searches for the power wireless base station and synchronizes with it in time slots. By identifying the content of the synchronization word, the power wireless terminal enters the corresponding working state, including adaptive rate and fixed rate.

4. The TDMA-based power equipment access method according to claim 1, characterized in that, the access time slot is used for the access of the power wireless terminal. At this time, the power wireless base station is in the listening state, the power wireless terminal is in the sending state, and the power wireless terminals perform random competition access in the time slot ALOHA manner. The power wireless terminal confirms its access status through the broadcast time slot, and uses whether it is assigned a communication time slot as the criterion for whether to access. If the power wireless terminal fails to access successfully, it continues to perform random access in the ALOHA manner in the next subframe. If it fails to access successfully in multiple superframes, the power wireless terminal switches the communication frequency and communication parameters and performs access attempts until it accesses the system.

5. The TDMA-based power equipment access method according to claim 1, characterized in that, the broadcast time slot is used for the transmission of power wireless base station broadcast information, including access response, time slot scheduling, and telemetry response.

6. The TDMA-based power equipment access method according to claim 1, characterized in that, the downlink transmission time slot is used for the downlink data link of the power wireless terminal. Since the number of power wireless terminals is greater than the set value, the downlink transmission time slots are distributed in a discrete form and alternate with the uplink transmission time slots to balance the data transmission delay.

7. The TDMA-based power equipment access method according to claim 1, characterized in that, the uplink transmission time slot is used for the power wireless base station to send remote control information. When the number of time slot scheduling instructions is more than the set value, it can also be used to send time slot scheduling instructions.

8. The TDMA-based power equipment access method according to claim 7, characterized in that, When there are multiple services to be sent at the power wireless base station, calculate the priority P according to the service waiting time and the upper limit of service delay i , which is expressed as: where t is the current waiting time of this service, and a represents the longest waiting time that this service can tolerate.

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