CN110913464A

CN110913464A - Low-power consumption wireless photographing transmission system

Info

Publication number: CN110913464A
Application number: CN201911134773.8A
Authority: CN
Inventors: 张孝龙; 王国炎
Original assignee: Wuhan Gewei Electronic Technology Co Ltd
Current assignee: Wuhan Gewei Electronic Technology Co Ltd
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2020-03-24
Anticipated expiration: 2039-11-19
Also published as: CN110913464B

Abstract

The invention discloses a low-power-consumption wireless photographing transmission system which comprises a low-power-consumption camera, a concentrator and a communication server, wherein the low-power-consumption camera is communicated with the concentrator through a wireless network, the concentrator is communicated with the communication server through a remote communication network, the concentrator is used for being responsible for wireless access and photo data transmission of the low-power-consumption camera, and the communication server is used for being responsible for identity authentication, connection management, working channel allocation, whole-network low-power-consumption camera allocation scheduling, concentrator load balancing, photo command issuing and photo collection and uploading of the concentrator. The invention has low power consumption and cost of the camera, high transmission rate, low power consumption awakening and frequency band interference avoidance as much as possible.

Description

Low-power consumption wireless photographing transmission system

Technical Field

The invention relates to a low-power-consumption wireless photographing transmission system which is suitable for low-power-consumption wireless photographing and transmission and is suitable for application scenes that a camera is powered by a battery, and photos are discontinuous and not strong in real time, such as photographing and transmission of supermarket commodity display management photos.

Background

With the development of the technology of the internet of things and the improvement of the image recognition technology, convenience is brought to the monitoring and management of the field condition in recent years. However, in many practical applications, the camera is powered only by a battery, continuous photographing is not required, and the requirement on the real-time performance of the taken pictures is not high. For example, the display management of supermarket commodities can obtain a scene photo regularly or according to needs, and whether the actual commodity placing mode is consistent with the designed display mode or not can be obtained through the recognition and analysis of the scene photo. Such application scenarios have low requirements on continuity and instantaneity of on-site photos, but are very sensitive to power consumption and cost. Some existing general wireless transmission schemes, such as ZigBee, WiFi, bluetooth, etc., are not well suited for such application scenarios. Firstly, the ZigBee transmission rate is not high, and the photo transmission delay and the power consumption are large. WiFi communication speed is fast, and the price is cheap, but hardly realizes low-power consumption and awakens to the WiFi frequency channel transmission distance is close, and the frequency channel is disturbed seriously. Bluetooth communication speed is fast, and power consumption and cost are low, but communication distance is very close, also faces the interference of 2.4G frequency band increasing complexity.

Disclosure of Invention

The invention provides a low-power wireless photographing transmission system, which at least partially solves the technical problem.

The invention is realized by the following steps: the invention discloses a low-power-consumption wireless photographing transmission system which comprises a low-power-consumption camera, a concentrator and a communication server, wherein the low-power-consumption camera is communicated with the concentrator through a wireless network, the concentrator is communicated with the communication server through a remote communication network, the concentrator is used for being responsible for wireless access and photo data transmission of the low-power-consumption camera, and the communication server is used for being responsible for identity authentication, connection management, working channel allocation, whole-network low-power-consumption camera allocation scheduling, concentrator load balancing, photo command issuing and photo collection and uploading of the concentrator.

Further, the low power consumption camera includes an MCU module, a power supply circuit, an external memory circuit, an image sensor, and a wireless transceiving chip, the power circuit is used for supplying power to the low-power consumption camera, the external storage circuit, the image sensor and the wireless transceiving chip are respectively connected with the MCU module, the MCU module drives an external storage circuit through an I2C interface, the external storage circuit is used for saving factory configuration information of the camera, the image sensor uses a clock signal provided by an MCU module, the MCU module configures the image sensor and completes the focusing function through an I2C interface, the photo data is captured through the DCMI interface, the MCU module controls the wireless transceiving chip by using the SPI interface, when the low-power-consumption camera is not connected to the network, a network access application is sent to the concentrator at regular time, and after the low-power-consumption camera is connected to the network, the wireless transceiving chip wakes up at regular time to wait for the management and photographing command of the concentrator.

Furthermore, the power supply circuit comprises a DC-DC voltage stabilizing circuit, a first LDO voltage stabilizer, a second LDO voltage stabilizer and a third LDO voltage stabilizer, wherein the input end of the DC-DC voltage stabilizing circuit is connected with an input power supply, the output end of the DC-DC voltage stabilizing circuit is connected with a VCC power supply terminal through a first MOS switch, the input end of the first LDO voltage stabilizer is connected with the input power supply, the output end of the first LDO voltage stabilizer is connected with the VCC power supply terminal through a Schottky diode, and the VCC power supply terminal is used for outputting VCC voltage to supply power to the MCU module; the second LDO stabiliser is used for converting VCC voltage into 2.8V and gives image sensor power supply, the third LDO stabiliser is used for converting VCC voltage into 1.5V and gives image sensor power supply, and DC-DC voltage stabilizing circuit, second LDO stabiliser, third LDO stabiliser are all in the off-state when not shooing, just open its power when only needing-time.

The LDO power supply has low conversion efficiency but low quiescent current, and the LDO is only used for supplying power to the system in a sleep mode and reducing the sleep current. The DCDC power supply has high conversion efficiency, but has large quiescent current, the DCDC is closed in a sleep mode, and the DCDC is opened to supply power to a system only after being awakened, so that the power supply conversion efficiency is improved. The first MOS switch is used for enabling the DCDC voltage stabilizing circuit to be connected with the first LDO in parallel, and during the sleep period, after the DCDC is closed, the output of the LDO flows backwards to the DCDC circuit to increase the static sleep current.

During system operation, the DCDC power supply is turned on. The Schottky diode can prevent the DCDC output voltage from flowing backward to the LDO circuit, so that the LDO circuit is abnormal. The effect of the actual Schottky diode is the same as that of the MOS switch, but the voltage drop of the MOS switch is very low when the MOS switch is in large current, so that the Schottky diode is more suitable for being used under the large current. The voltage drop of the Schottky diode is large under the condition of large current, and the Schottky diode is only suitable for outputting the LDO which is a path of small current.

The second LDO voltage stabilizer, the third LDO voltage stabilizer and the chip are provided with control switch signals. All the MOS switches are controlled, and the second LDO voltage stabilizer and the third LDO voltage stabilizer are controlled to be switched by the IO of the MCU. During the sleep period, the MCU is powered by the LDO, and the DC-DC voltage stabilizing circuit is turned on after the MCU is awakened.

The power supply circuit further comprises a battery voltage measuring circuit, the input power supply adopts a battery, the input end of the battery voltage measuring circuit is connected with the input power supply through a second MOS switch, and the output end of the battery voltage measuring circuit is connected with the ADC port of the MCU module and used for measuring the battery voltage and judging the battery capacity. When the battery voltage needs to be measured, the second MOS switch is turned on, and the power consumption of the ADC sampling input voltage division circuit is reduced.

Further, the external storage circuit comprises an EEPROM, the EEPROM is connected with the MCU module, and a third MOS switch is arranged between the MCU module and the VCC voltage and used for switching on or off a power supply of the EEPROM. And the power supply of the EEPROM is turned on only when the data of the EEPROM needs to be read and written, so that the standby working current of the EEPROM at ordinary times is reduced.

Furthermore, the concentrator comprises an MCU module, a power supply circuit, an external storage circuit, a wireless communication circuit and an uplink communication interface circuit, wherein the power supply circuit is used for supplying power to the concentrator; the external storage circuit is used for storing factory information, equipment configuration, camera files, network operation information and cached photo information.

Further, the external storage circuit comprises a FLASH and an SDRAM, the FLASH is driven by an SPI interface and used for storing factory information, device storage configuration, camera files, network operation, and other information, and the SDRAM is driven by an FMC interface and used for caching information such as photos.

Furthermore, the wireless communication circuit comprises two wireless communication interfaces, one is used for high-speed communication, an ISM frequency band and a private access protocol are used, access of the low-power-consumption camera is supported, and the other is used for long-distance low-speed communication and reserved for expansion of other applications.

Further, the uplink communication interface circuit comprises one or more of an ethernet interface, a fiber optic communication interface, a WiFi interface, and a 4G/5G/private network communication interface.

Furthermore, the uplink communication interface circuit comprises one path of Ethernet interface, one path of optical fiber communication interface, one path of WiFi interface and one path of 4G/5G/private network communication interface, wherein the interfaces exist, and one is selected from more interfaces when the uplink communication interface circuit is used. And an appropriate uplink communication interface can be configured and selected according to the requirements of the field environment. Of course, a plurality of uplink communication interfaces can also be used simultaneously, the concentrator can select the available communication interface with the highest priority according to the priority, and a plurality of links exist simultaneously, so that the failure of a certain interface circuit can be avoided.

The uplink communication interface selects Ethernet, optical communication, WiFi, 4G/5G/private network or other bus interfaces, is connected to the communication server in a TCP mode, and uses a private protocol to complete network management and data transmission. Further, the communication server comprises a remote communication interface and an application service interface, wherein the remote communication interface is used as a TCP server side and allows the concentrator device to be accessed in a TCP mode and complete network management and data transmission by using a private protocol, and the application service interface is used for exchanging data with the application server by using a TCP or Redis mode.

Further, the communication server manages a plurality of concentrators, each concentrator managing a plurality of low-power-consumption cameras; each concentrator uses a different operating channel, the channel number of which is uniformly assigned by the communication server.

After the low-power-consumption cameras are electrified, firstly sending a network access application to the concentrator, and recording field intensity values of all low-power-consumption camera emission signals by the concentrator to form a field intensity recording table;

the server reads the field intensity recording tables of all the concentrators by using the read information command at intervals, judges whether the low-power cameras in the field intensity recording tables are already allocated to the concentrators for management, if the low-power cameras are not allocated, allocates the low-power cameras to the proper concentrators according to a camera address allocation algorithm, then the server uses the allocation camera command to send the addresses of the low-power cameras to the concentrators, and the concentrators respond to confirm or deny frames after receiving the allocation camera command;

when the concentrator receives a network access application of a low-power-consumption camera managed by the concentrator, the low-power-consumption camera is configured to enter a network of the concentrator, and a photographing task can be executed only after the low-power-consumption camera accesses the network to a certain concentrator;

after the concentrator is powered on or reset, connection is initiated to the server, and after the connection is successfully established, the server reads basic information of the concentrator, carries out initialization setting on the concentrator, and distributes working channel numbers to the concentrator.

Further, assigning the low power cameras to the appropriate concentrators based on a camera address assignment algorithm, comprising the steps of:

s1) traversing one camera in the field intensity recording table to determine whether the camera is assigned a concentrator;

s11) if the concentrator is not assigned to the camera, selecting an appropriate concentrator and assigning it, and executing step S2); selecting an appropriate concentrator includes: if the signal intensity is better than the set value, selecting the concentrator with the least number of the administered cameras, and if the signal intensity is less than the set value, selecting the concentrator with the strongest signal intensity;

s12) if the camera has already distributed a concentrator, determining whether the distributed old concentrator is on the network, if the old concentrator is not on the network, continuing to determine whether the conditions that the old concentrator has no signal and the new concentrator has signal strength better than the set value are satisfied, if so, selecting the concentrator having signal strength better than the set value and the number of administered cameras is the least, deleting the camera from the old concentrator and adding the camera to the new concentrator, executing step S2), if not, executing step S2); if the old concentrator is on the network, continuously judging whether the photographing success rate is greater than or equal to a set value or not, if the photographing success rate is greater than or equal to the set value, executing step S2), if the photographing success rate is less than the set value, judging whether a new concentrator with the field intensity superior to the set value, the photographing success rate greater than the current photographing success rate and the administered camera not full exists or not, if not, executing step S2), if so, selecting the new concentrator with the highest photographing success rate, deleting the camera from the old concentrator, adding the camera to the new concentrator, and executing step S2);

s2) whether it is the last camera in the field strength table, if so, the camera assignment is ended, otherwise, the process returns to step S1).

Further, the server reads the field intensity recording tables of all the concentrators at intervals by using an information reading command, then calculates the adjacent relation among all the concentrators, and calculates and distributes the working channel number of the concentrator if the concentrator does not distribute the channel number.

Further, the working channel number of the concentrator is calculated and distributed, and the method comprises the following steps:

SS8) reading the updated field intensity recording table of the concentrator, then removing the field intensity value with invalid life value, and calculating the adjacent relation table of the concentrator;

SS9) to select a concentrator;

SS10) determining whether the concentrator selected in step SS9) has already been allocated with a channel, if so, executing step SS13), if not, initializing the use weight of each channel, wherein the smaller the weight is, the higher the availability is, the weight is greater than or equal to the threshold value, the unavailability is indicated, marking the channel already allocated to other concentrators as unavailable, and executing step SS 11);

SS11) traversing and selecting an adjacent concentrator, wherein the adjacent concentrator means that the number of common cameras existing between two concentrators is larger than a set value, judging whether the adjacent concentrator has distributed channels, if so, adding a set value to the weight values of the upper and lower channels of the working channel of the adjacent concentrator, and adjusting the weight values of other adjacent channels according to the number of the common cameras, and executing the step SS12), and if not, directly executing the step SS 12);

SS12) determining whether the last adjacent concentrator is selected in step SS11), if not, returning to continue to execute step SS11), if yes, selecting the channel with the minimum weight value from the channels with the minimum weight value, if at least two channels with the minimum weight value, selecting the channel with the maximum number from the channels with the minimum weight value to be distributed to the concentrator, and executing step SS 13);

SS13) determines whether the last concentrator was selected in step SS9), if so, the channel allocation calculation is complete, otherwise, the process returns to step SS 9).

Further, the method also comprises the steps of timing triggering or manual triggering global network optimization; the global network optimization step comprises moving a camera with low photographing success rate, marking a non-movable camera, and iteratively calculating an optimization network, and specifically comprises the following steps:

SSS1) reading all updated concentrator field intensity record tables, and calculating a concentrator adjacent relation table;

SSS2) traversing to select a concentrator to be optimized;

SSS3) traversing a camera under the concentrator of the selection step SSS2), determining whether the photographing success rate of the camera reaches 100%, if not, selecting a concentrator with the strongest signal and the historical photographing success rate higher than that of the local concentrator, identifying immobility in the new concentrator, and continuing to execute the step SSS 6); if yes, go to step SSS 4);

SSS4), judging whether other field intensity values exist in the camera, if not, executing a step SSS5), if so, judging whether the historical photographing success rate of the camera in other concentrators is lower than that of the camera, if so, executing a step SSS5), and if not, executing a step SSS 6);

SSS5) marking the camera as immobile, i.e. not participating in the optimization, proceed to step SSS 6);

SSS6) determining whether SSS3) is the last camera in the concentrator, if so, performing SSS7), and if not, returning to continue SSS 3);

SSS7) determining whether the last concentrator to be optimized is selected in step SSS2), if so, executing step SSS8), and if not, returning to continue executing step SSS 2);

SSS8), and the iteration number is initialized to 0;

SSS9) traversing to select a concentrator to be optimized;

SSS10) traversing and selecting one neighboring concentrator, where the neighboring concentrator refers to the number of common cameras existing between two concentrators is greater than a set value, and if the difference between the numbers of cameras managed by the two neighboring concentrators is greater than the set value and there are mobile cameras, i.e., cameras in the common area of the two neighboring concentrators, except the cameras marked as immobile in the above step, the other cameras are all mobile cameras, moving the mobile cameras in the common area of the two neighboring concentrators from the concentrator managing more cameras to the concentrator managing less cameras according to a set moving rule, adding n to the number of mobile cameras, where n is the number of cameras already moved when the two neighboring concentrators reach equilibrium, and continuing to execute the SSS 11); otherwise, step SSS11 is executed directly);

SSS11) determining whether the last neighbor concentrator is selected in step SSS10), if yes, performing step SSS12), and if not, returning to continue performing step SSS 10);

SSS12) determining whether the selected in step SSS9) is the last concentrator to be optimized, if not, returning to continue to execute step SSS9), if so, adding 1 to the iteration number, and determining to execute step SSS13 when the number of moves is 0 or the iteration number is greater than a set value, otherwise, starting to zero-clear the number of moves in a new round, and executing step SSS 9);

SSS13) comparing the files before optimization, judging whether the files are changed, if so, executing the step SSS14), if not, finishing the network optimization;

SSS14) issues instructions to adjust the address of the low-power-consumption camera governed by the concentrator, and the network optimization is completed.

By moving from more to less, including two adjacent concentrators, one managing more cameras and one managing less cameras, it is necessary to move the movable cameras within their common area from more to less, thus making the concentrator load locally balanced. The algorithm idea is a divide-and-conquer method, a local equalization algorithm is used, and the purpose of network global equalization is achieved through Torontal iteration.

The number difference of cameras refers to the difference between the numbers of cameras managed by two adjacent concentrators (one concentrator to be optimized and the other adjacent concentrator). Two adjacent concentrators, the cameras in their common area, are all moveable cameras, except the cameras marked as non-moveable in the above step. "move" indicates a change in camera ownership, indicating that the camera is switched from one concentrator to another.

n is the number of cameras that have moved when the equalization is reached for two adjacent concentrators. The counting accumulation of the 'moving number' represents the number of the cameras which have moved in one iteration, and if no camera moves, the whole network can not be optimized, and the optimization process is finished.

This camera cannot be moved after the identification is not movable, and in the following network optimization, it cannot be moved to another concentrator even if it is in the common area of both concentrators.

Further, the set movement rules include that the historical photographing record is not moved below the record, if the signal is not moved less than the set value in the new concentrator (the signal strength of the camera in the new concentrator, if the signal is less than the set value in the new concentrator, the situation prohibits movement), preferentially moving the camera with strong signal in the new concentrator and moving until the number of cameras is different from the set value; the difference between the number of cameras having a strong priority movement signal and the number of cameras to be moved differs by a set value of 1, but it is needless to say that the smaller the difference between the numbers of cameras managed by two adjacent concentrators, the better the network balance. Therefore, if there are still cameras that can move in the common area, the movement is made as much as possible so that the difference is minimized. Of course, the difference may be greater than the set value if there are no more movable cameras in the common area.

When a plurality of cameras in a common area of two adjacent concentrators can move, the camera signal intensity in the new concentrator is preferentially selected. Thus, the communication quality is better when the camera arrives at the new concentrator.

Calculating a concentrator adjacency list that counts the number of common cameras that exist between both concentrators, comprising the steps of:

SS1) to select a concentrator;

SS2) through one camera in the field strength record table of the concentrator selected in the selection step SS 1);

SS3) to select the next concentrator;

SS4) judges whether the camera selected in the step SS2) is in the field intensity recording table of the concentrator selected in the step SS3), if so, the total number of adjacent cameras of the concentrator selected in the step SS1) and the concentrator selected in the step SS3) is added with 1, and the step SS5) is executed; if not, directly executing step SS 5);

SS5) judging whether the concentrator selected in the step SS3) is the last concentrator, if not, returning to continue the step SS 3); if yes, execute SS 6);

SS6) determining whether the last camera in the field intensity recording table selected in step SS2) is selected, and if not, returning to continue to step SS 2); if yes, go to step SS 7);

SS7) judging whether the concentrator selected in the step SS1) is the penultimate concentrator, if not, returning to continue to execute the step SS 1); if yes, the calculation of the concentrator adjacent relation table is completed.

Before reading the field intensity meter of the concentrator, the server needs to send a concentrator updating field intensity meter instruction to all the concentrators, and then waits for 240 seconds before reading the field intensity meter of the concentrator.

Further, a GWIOT-B protocol is adopted between the low-power-consumption camera and the concentrator for wireless communication; the GWIOT-B protocol network layer contains 14 commands, which are: denying, confirming, network access application, network configuration, clock synchronization, reading state, response state, starting photographing, power control, field intensity refreshing, camera broadcasting, stopping working, rate control and application data; after the low-power camera accesses the network, the medium access is initiated by the concentrator and accessed in a mode of response of the low-power camera;

the concentrator and the server communicate by adopting a GWIOT-C protocol, wherein the GWIOT-C protocol comprises 23 commands which are respectively as follows: denying, confirming, reading information, responding information, setting a concentrator, distributing a camera, issuing an upgrade file, starting real-time photographing, reading new photo information, responding the new photo information, deleting a new photo, reading a packet of photo data, responding a packet of photo data, setting uplink network parameters, reading uplink network parameters, responding uplink network parameters, setting an off-time period, reading an off-time period, responding an off-time period, updating a field intensity table of the concentrator, uplink heartbeat response and concentrator reset. A star-net structure is used between the low power cameras and the concentrator.

Further, when the low power consumption camera is not connected to the network, the low power consumption camera sends a network connection application command at a time interval on a public channel FCC00, then waits for a network configuration command of the concentrator on the public channel FCC01, if the network configuration command is not received within a first set time period, the low power consumption camera enters a sleep mode, and the low power consumption camera repeats the process until the network configuration command is received;

the concentrator receives the network access application command of the low-power-consumption camera, if the low-power-consumption camera belongs to self management, a network configuration command is sent in a public channel FCC01, the network configuration command comprises the working channel, the maximum time slot, the working time slot, the time slot time, the maximum working time and the current system time information of the low-power-consumption camera, after the low-power-consumption camera receives the network configuration command of the concentrator, the time slot timer of the low-power-consumption camera is synchronized once, then a confirmation frame is responded, and then the low-power-consumption camera is switched to a network access mode;

after the low-power-consumption camera accesses the network, the low-power-consumption camera wakes up once at an allocated working time slot at intervals, waits for a command of a concentrator at an allocated working channel, firstly synchronizes a self time slot timer once if the command of the concentrator is received in a second set time slot, then executes the command issued by the concentrator, and if the low-power-consumption camera does not receive any command of the concentrator in a third set time slot, the low-power-consumption camera needs to be separated from a network access mode and resends a network access application command to apply for network access.

Further, the concentrator broadcasts a clock synchronization command on a working channel at intervals, after receiving the clock synchronization command, the low-power-consumption camera firstly synchronizes the self time slot timer once and then immediately enters a sleep mode, and the clock synchronization command is only used for synchronizing the time slot timer of the low-power-consumption camera and maintaining the on-line state of the low-power-consumption camera;

the concentrator broadcasts a field intensity refreshing command once in a working channel at intervals, after the low-power-consumption camera receives the field intensity refreshing command, the camera broadcasting command is used for broadcasting once in a public channel FCC00, and the camera broadcasting command comprises the battery voltage, the working state, the firmware version, the transmitting power and the communication rate information of the low-power-consumption camera and is used for refreshing the field intensity recording information of the low-power-consumption camera in other concentrators; and if the concentrator does not receive the battery voltage, the working state, the firmware version, the transmitting power and the communication rate information of the low-power consumption camera within the fourth set time period, directly reading the information of the low-power consumption camera by using a reading state command, and responding by using a response state command by using the low-power consumption camera.

The concentrator judges the signal quality of the low-power-consumption camera according to the success rate of picture transmission, the packet loss rate of picture transmission and the signal strength during picture transmission, if the strength of the signal transmitted by the low-power-consumption camera is very strong, namely exceeds the upper limit set value, the concentrator reduces the wireless transmitting power of the low-power-consumption camera by using a power control command, reduces the average working current of the low-power-consumption camera, if the strength of the signal transmitted by the low-power-consumption camera is very weak, namely is lower than the lower limit set value, and the packet loss rate of picture transmission is too high, namely exceeds the set value, the concentrator increases the wireless transmitting power of the low-power-consumption camera by using the power control command, reduces the;

if the low-power camera still has higher packet loss rate or higher failure rate of picture transmission when transmitting pictures under the maximum transmitting power, the concentrator uses the rate control command to reduce the data rate of the wireless communication of the low-power camera, improve the link budget of a wireless channel and achieve the purpose of stable transmission; if the communication quality of the low-power-consumption camera is good at a low speed and the signal strength reaches a threshold value, the concentrator uses a speed control command to improve the data rate of the wireless communication of the low-power-consumption camera, so that the picture transmission time is shortened, and the aim of reducing the average working current of the low-power-consumption camera is fulfilled.

The concentrator uses a stop working command to set the non-working time period of the low-power consumption camera, and the low-power consumption camera enters a deep sleep mode in the non-working time period and does not execute any instruction, so that the average standby current is further reduced; after the low-power camera is awakened from the deep sleep mode, the low-power camera needs to reapply for network access.

On the server, the off-time of the low power consumption camera is configured, during which time the low power consumption camera goes into deep sleep. The server uses a command for setting the non-operation time period to set the non-operation time to the concentrator, and then the concentrator controls the low-power consumption camera to enter a deep sleep mode. The server reads the time parameter sent to the concentrator by using the command of reading the non-working time period, and the concentrator returns the time parameter by using the command of responding the non-working time period.

After receiving a photographing starting command sent by a concentrator, a low-power-consumption camera firstly responds to a confirmation frame, then turns on a power supply of an image sensor, initializes the image sensor and completes lens focusing, and then captures a picture from a video stream.

The server is used as a TCP server side, the concentrator is used as a TCP client side, an uplink communication interface is initialized after the concentrator is powered on or reset, then TCP connection is initiated to the server, after the TCP connection is successfully established, the server firstly reads the ID, the communication public key and the ID certificate information of the concentrator, if the ID certificate passes verification, the concentrator is allowed to be accessed, and if the ID certificate fails verification, the TCP connection of the concentrator is disconnected, so that illegal connection access or pirate equipment access is prevented; the server reads the ID, communication public key and ID information of the concentrator to verify the ID, if the ID is verified, the concentrator is allowed to access, if the ID is not verified, the concentrator is disconnected,

the server sends an uplink heartbeat command to the concentrator at intervals, the concentrator responds with the uplink heartbeat response command after receiving the uplink heartbeat command, if the concentrator does not receive any command of the server within a fifth set time period, the failure of the TCP connection is judged, and the concentrator needs to actively reestablish the TCP connection.

When the timing photographing time configured in the server reaches or receives a photographing instruction of the application server, the photographing instruction is issued to the concentrator by starting a real-time photographing instruction, the photographing instruction is continuously sent by a plurality of pieces, after the concentrator receives the real-time photographing instruction, the photographing instruction is stored in an instruction queue and is executed one by one, at the moment, the server continuously inquires whether the photographing process is completed or not by reading a new photograph information instruction until the photographing is successful or overtime, if the concentrator responds to the new photograph information instruction, the photographing process is prompted to be completed, and photograph information is given, at the moment, the server reads the photograph data one by reading a bundle of photograph data instructions, so that the server also reads the whole photograph data one by one bundle, and after the server reads the photograph, the photograph stored in the concentrator is deleted by sending a new photograph deleting instruction.

Each concentrator uses frequency division multiplexing of different working channels, and the working channels are uniformly distributed and managed by the server.

The camera address assignment algorithm is primarily used to assign new low power cameras to the concentrator.

In the actual system operation process, the concentrators and the low power consumption cameras may be powered on sequentially, so the allocation of the low power consumption cameras may not be optimal, and the number of the low power consumption cameras managed by each concentrator may be unbalanced. The network optimization algorithm is mainly used for optimizing a low-power-consumption camera with low photographing success rate to a more appropriate concentrator, and balancing the load of each concentrator as much as possible. And the server simultaneously updates and reads the field intensity record tables of all the concentrators every day at the configuration time, then removes the field intensity values with invalid life values, and then constructs the concentrator adjacent relation table. The low power camera with low success rate of taking pictures is then optimized into a better concentrator. And finally, a divide-and-conquer method is used for multi-round iteration, so that the purpose of balancing the load of the whole network concentrator as much as possible is achieved.

The low-power-consumption cameras send network access applications in a public channel, the server senses the existence of the low-power-consumption cameras, the low-power-consumption cameras are distributed to proper concentrators, and then the corresponding concentrators are configured with the low-power-consumption cameras to enter own networks. The server sends an instruction to the concentrator to start the photographing process. After receiving the photographing instruction, the concentrator wakes up the low-power-consumption camera to take a photograph, then obtains photograph data by using a data transmission command of a GWIOT-B protocol, and then transmits the photograph to the server by using a related command of the GWIOT-C protocol.

The method comprises the steps that a server sends a photographing command to a concentrator, the server continuously reads a photographing state until photographing is successful or overtime, the concentrator firstly sends a photographing awakening command to a low-power-consumption camera after receiving the photographing command, the low-power-consumption camera firstly responds to the command after receiving the photographing awakening command, then a power supply of an image sensor is turned on, the image sensor is initialized, then a photo is captured, after photographing is completed, photo data are transmitted to the concentrator in a sub-packaging mode, and the concentrator transmits the photo data to the server.

The concentrator receives the network access application command of the low-power-consumption camera, the field intensity value of the signal transmitted by the low-power-consumption camera is recorded, the server reads the field intensity recording tables of all the concentrators at intervals by using the information reading command, then the adjacent relation among all the concentrators is calculated according to the field intensity recording tables, if the concentrator does not distribute channel numbers, the weight of each channel is calculated according to rules, the lower the weight is, the higher the priority is, then a channel with the lowest weight is selected, and the concentrator is set by using the concentrator setting command to distribute the channel to the concentrator. If the weights of a plurality of channels are the same, selecting the channel with the large channel number to be distributed to the concentrator;

and the server reads the field intensity record tables of all the concentrators by using the information reading command at intervals, and judges whether the low-power-consumption cameras in the field intensity record tables are allocated to the specific concentrator management. If the low power consumption camera is not allocated, the low power consumption camera is allocated to a proper concentrator according to the principle of signal intensity and equalization, and then the server issues the address of the low power consumption camera to the concentrator by using an allocation camera command. The concentrator, upon receiving the assign camera command, acknowledges or denies the frame.

The invention has the beneficial effects that: the average standby current and the working current of the camera are very low, the camera can wake up to take a picture at regular time or in real time, the picture is transmitted to the concentrator in an ISM frequency band according to a private protocol, then the picture is transmitted to the server through the concentrator, the on-site picture acquisition work is completed, and original data are collected for an image recognition and application system.

By adopting the system of the invention, the power consumption and the cost of the camera are low, the transmission rate is high, the low-power consumption awakening can be realized, and the frequency band interference is avoided as much as possible.

The concentrator judges the signal quality of the low-power-consumption camera according to the success rate of picture transmission, the packet loss rate of picture transmission and the signal strength during picture transmission. If the intensity of the low-power camera transmitting signal is strong, the concentrator can use the power control command to reduce the wireless transmitting power of the low-power camera, so as to achieve the purpose of reducing the average working current of the low-power camera. If the strength of the signal transmitted by the low-power-consumption camera is very weak, which causes the packet loss rate of the photo transmission to be too high, the concentrator can use the power control command to increase the wireless transmission power of the low-power-consumption camera, thereby reducing the retransmission times of the photo data packet and the time of the photo transmission. If the low-power camera still has a higher packet loss rate or a higher failure rate of picture transmission when transmitting pictures under the maximum transmission power, the concentrator can use the rate control command to reduce the data rate of the wireless communication of the low-power camera, thereby improving the link budget of a wireless channel and achieving the purpose of stable transmission. If the communication quality of the low-power-consumption camera is good at a low speed and the signal strength reaches a threshold value, the concentrator can use a speed control command to improve the data speed of the wireless communication of the low-power-consumption camera, so that the picture transmission time is shortened, and the aim of reducing the average working current of the low-power-consumption camera is fulfilled.

The network optimization of the invention is divided into success rate optimization and global optimization, and has the following advantages:

1. the invention optimizes the camera with low photographing success rate (low communication success rate) and improves the communication success rate.

2. The invention ensures that the concentrator governs the cameras in a balanced way and improves the photographing speed.

3. The invention improves the network robustness, and leads the camera distribution to be more reasonable through the optimization of the network.

Drawings

FIG. 1 is a block diagram of the system architecture of the present invention;

FIG. 2 is a functional block diagram of a low power consumption camera of the present invention;

FIG. 3 is a functional block diagram of a concentrator of the present invention;

FIG. 4 is a flow chart of the low power camera network access of the present invention;

FIG. 5 is a flowchart of the photographing operation of the present invention;

FIG. 6 is a flow chart of a camera address assignment algorithm of the present invention;

FIG. 7 is a flow chart of a method for assigning channels for concentrator operations in accordance with the present invention;

FIG. 8 is a flow chart of a network optimization algorithm of the present invention;

FIG. 9 is a diagram of concentrator adjacency according to the present invention;

fig. 10 is a diagram of the automatic power/automatic rate control state transition of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 10, the embodiment discloses a low power consumption wireless photographing transmission system, which includes a low power consumption camera, a concentrator and a communication server, wherein the low power consumption camera communicates with the concentrator through a wireless network, the concentrator communicates with the communication server through a remote communication network, the concentrator is responsible for wireless access of the low power consumption camera and transmission of photograph data, and the communication server is responsible for identity authentication, connection management, allocation of working channels and allocation scheduling of the low power consumption cameras in the whole network, load balancing of the concentrator, and issuing of photographing instructions and collection and uploading of photographs.

Furthermore, the uplink communication interface circuit comprises one path of Ethernet interface, one path of optical fiber communication interface, one path of WiFi interface and one path of 4G/5G/private network communication interface, wherein the interfaces exist, and one is selected from more interfaces when the uplink communication interface circuit is used. And an appropriate uplink communication interface can be configured and selected according to the requirements of the field environment. Of course, a plurality of uplink communication interfaces can also be used simultaneously, the concentrator can select the available communication interface with the highest priority according to the priority, and a plurality of links exist simultaneously, so that the failure of a certain interface circuit can be avoided. The uplink communication interface selects Ethernet, optical communication, WiFi, 4G/5G/private network or other bus interfaces, is connected to the communication server in a TCP mode, and uses a private protocol to complete network management and data transmission.

Further, the communication server comprises a remote communication interface and an application service interface, wherein the remote communication interface is used as a TCP server side and allows the concentrator device to be accessed in a TCP mode and complete network management and data transmission by using a private protocol, and the application service interface is used for exchanging data with the application server by using a TCP or Redis mode.

As shown in fig. 1, the low power wireless photograph transmission system includes three major parts, a "low power camera", a "concentrator", and a "communication server". The 'low power consumption camera' is powered by a battery, has low standby and working current and supports a self-defined local low power consumption wireless access protocol. The "concentrator" is responsible for wireless access to the "low power camera" and photo data transmission. The communication server is responsible for identity authentication, connection management and working channel distribution of the concentrator, and is also responsible for distribution scheduling of the low-power-consumption cameras in the whole network, load balancing of the concentrator, sending of photographing instructions, collection and uploading of photos and the like.

The "low power consumption camera" mainly includes power management, external storage, an image sensor circuit, and a wireless communication circuit.

As shown in fig. 2, the "low power consumption camera" mainly includes parts such as power management, external storage, an image sensor circuit, and a wireless communication circuit. The 'low-power consumption camera' is powered by a series connection of 4 batteries and 5 batteries or a lithium battery. The power supply part adopts a mode of connecting the DCDC with the LDO in parallel, the DCDC is turned off in the sleep mode to reduce the sleep current of the system, and the DCDC is turned on in the working mode to improve the power supply conversion efficiency. The input power supply is input into an ADC port of the single chip microcomputer after passing through the voltage division circuit, and the voltage of the battery is measured for judging the capacity of the battery.

The singlechip drives an external storage EEPROM through an I2C interface, and the EEPROM is used for storing information such as factory configuration of the camera.

The image sensor uses 2.8V and 1.5V power supply, and the power supply is in a turn-off state when not taking pictures, and the power supply is turned on only when needing to take pictures. The image sensor uses a single chip microcomputer to provide an 8MHz clock, the image sensor is configured through an I2C interface and completes the focusing function, and photo data are captured through a DCMI interface.

The wireless communication circuit uses the SPI interface to control the wireless transceiver chip. When the 'low-power-consumption camera' is not connected to the network, a network connection application is sent to the 'concentrator' at regular time. After the 'low-power camera' accesses the network, the wireless transceiver chip wakes up at regular time to wait for the management of the 'concentrator' and the command of taking a picture and the like.

The concentrator mainly comprises a power supply management part, an external storage part, a wireless communication circuit, an uplink communication interface circuit and the like.

As shown in fig. 3, the "concentrator" mainly includes several parts, such as power management, external storage, wireless communication circuit, and uplink communication interface circuit. The power supply part of the concentrator can input direct current voltage of 6V-36V, and can also use POE power supply input of 12V. The voltage stabilizing circuit is mainly divided into two paths, wherein one path converts input voltage into 5V through DCDC to supply power for an interface circuit, a radio frequency power amplifier and the like. The other path converts the input voltage into 3.6V through DCDC, and then supplies power to the main system through LDO voltage stabilization to 3.3V.

The external memory is divided into two parts. One part is 16MB data FLASH which is driven by an SPI interface and is used for storing information such as configuration, archives, network operation and the like. The other part is 64MB SDRAM driven by FMC interface for buffering information such as photos.

The wireless communication circuit comprises two paths of wireless communication interfaces. One path can be used for high-speed communication, the maximum rate can reach 1Mbps, an ISM frequency band and a private access protocol are used, and the access of a low-power camera is supported. And the other path is used for long-distance low-speed communication and reserved for expansion of other applications.

The uplink communication interface circuit comprises one path of Ethernet interface, one path of optical fiber communication interface, one path of WiFi interface and one path of 4G/5G/private network communication interface. The uplink communication interface can be selected from Ethernet, optical communication, WiFi, 4G/5G/private network or other bus interfaces, is connected to a communication server by means of TCP, and uses a private protocol to complete network management and data transmission.

The communication server comprises a remote communication interface and an application service interface. The remote communication interface is used as a TCP server, allows the concentrator device to be accessed in a TCP mode, and completes network management and data transmission by using a private protocol. The application service interface exchanges data with an application server by using a TCP (transmission control protocol) or Redis (Redis) mode and the like.

The communication server may manage a plurality of "concentrators", each of which may manage a plurality of "low power cameras", each of which uses a different operating channel, the channel numbers of which are uniformly assigned by the "communication server".

As shown in fig. 4, after the "low power consumption camera" is powered on, a network access application is sent to the "concentrator", and the "concentrator" records field intensity values of all signals transmitted by the "low power consumption camera" to form a field intensity recording table. After the 'communication server' reads all the 'concentrator' field intensity recording tables, the 'low-power-consumption cameras' managed by the 'communication server' are uniformly distributed to the 'concentrators' according to the signal intensity from the 'low-power-consumption cameras' to the concentrators. The concentrator can only configure the low-power consumption camera to enter the own network when receiving the network access application of the low-power consumption camera managed by the concentrator.

As shown in fig. 5, the "low power consumption camera" can only execute the photographing task after being networked to a certain "concentrator". After the communication server sends the photographing command, the photographing state is continuously read until the photographing is successful or overtime. After receiving the photographing command, the concentrator firstly sends a wake-up photographing command to the low-power-consumption camera. The "low power camera" receives the wake-up photo command, responds to the command, then powers on the image sensor, initializes the image sensor through the I2C interface, and then captures a picture from the DCMI interface. After the photo is taken, the photo data is transmitted to the concentrator in a subpackage mode, and the concentrator transmits the photo data to the communication server.

As shown in fig. 6, the "camera address assignment algorithm" is mainly used to assign a new "low power consumption camera" to a "concentrator". The communication server reads the field intensity record tables of all the concentrators at a time interval, removes the field intensity values with invalid life values and then constructs the concentrator adjacent relation table. If a new concentrator accesses the server, the working channel number is allocated to the new concentrator. And then distributing the 'low-power-consumption camera' to a certain 'concentrator' according to the data such as signal intensity, whether to access the network, the shooting success rate and the like.

In the actual system operation process, the "concentrator" and the "low power consumption camera" may be powered on successively, so the allocation of the "low power consumption camera" may not be optimal, and the number of the "low power consumption cameras" managed by each "concentrator" may be unbalanced. The network optimization algorithm is mainly used for optimizing a low-power-consumption camera with low photographing success rate to a more proper concentrator, and balancing the load of each concentrator as much as possible. The communication server updates and reads field intensity record tables of all concentrators every day at the configuration time, removes field intensity values with invalid life values, and then constructs a concentrator adjacent relation table. The "low power cameras" with low success rates of taking pictures are then optimized into better "concentrators". And finally, a divide-and-conquer method is used for multiple rounds of iteration to achieve the purpose of balancing the load of the concentrator of the whole network as much as possible.

the server uses the read information command at intervals to read the field intensity recording tables of all the concentrators and judges whether the low-power cameras in the field intensity recording tables are already allocated to the concentrators for management, if the low-power cameras are not allocated, the low-power cameras are allocated to the proper concentrators according to a camera address allocation algorithm (if the field intensity signals are good, the cameras are allocated to the concentrators with few cameras, so that preliminary balance can be achieved), then the server uses the allocation camera command to issue the addresses of the low-power cameras to the concentrators, and the concentrators respond to a confirmation or denial frame after receiving the allocation camera command;

the task of assigning low power cameras to appropriate concentrators is to time trigger, with the interval time configurable, with current engineering configurations of once every 5 minutes, according to the camera address assignment algorithm. It is equivalent to periodically check whether a new camera or concentrator is added to the network, or whether a concentrator is offline, or whether a camera with a low photographing success rate exists. If so, corresponding processing is carried out. This step is initially used to assign low power consumption cameras.

s12) if the camera has distributed the concentrator, then judging whether the distributed old concentrator is on the net, if the old concentrator is not on the net, then continuously judging whether the conditions that the old concentrator has no signal and the new concentrator has signal strength better than the set value (the set value is set according to the actual requirement, the value is configurable), if yes, then selecting the concentrator with signal strength better than the set value (the set value is set according to the actual requirement, the set value is-65 dBm in the embodiment) and the number of the administered cameras is the least, deleting the camera from the old concentrator, adding the camera to the new concentrator, executing step S2), if not, executing step S2); if the old concentrator is on the network, continuously determining whether the photographing success rate is greater than or equal to a set value (the set value is set according to actual needs, the set value is 70% in this embodiment), if the photographing success rate is greater than or equal to a set value (the set value is set according to actual needs, the set value is 70% in this embodiment), executing step S2, if the photographing success rate is less than a set value (the set value is set according to actual needs, the set value is 70% in this embodiment), determining whether there is a new concentrator whose field strength is better than the set value (the set value is set according to actual needs, the set value is-65 dBm in this embodiment), the photographing success rate is greater than the current photographing success rate and the cameras are not fully managed, if not, executing step S2), if so, selecting the new concentrator with the highest photographing success rate, deleting the camera from the old concentrator, and adding, performing step S2);

s2) whether it is the last camera in the field strength table, if so, the camera assignment is ended, otherwise, the process returns to step S1). This is the case to prevent a concentrator from dropping, and after an old concentrator drops, the camera needs to be scheduled to another concentrator, which is the new concentrator.

The camera address assignment algorithm is shown in fig. 6. The server reads the field strength tables of all concentrators simultaneously every 10 minutes. The camera address allocation algorithm is mainly used for allocating a new camera to the concentrator, so that the field intensity table of the concentrator can be directly read before the algorithm is executed, and a concentrator updating field intensity table instruction does not need to be issued. In the process, if the field intensity table reading of the individual concentrator fails, the retry is carried out twice, and if the field intensity table reading of the concentrator fails after the retry, the concentrator does not participate in the calculation of the current round. The cameras under its jurisdiction are temporarily unchanged. If the concentrator cannot read the field intensity table after 3 times of networking, or the TCP connection is disconnected for more than 30 minutes, the concentrator can be considered to be abnormal, and the cameras governed by the concentrator can be deleted and added into other concentrators.

After the field intensity meter is maintained, the adjacent relation table of the concentrator is calculated firstly, so that the position relation of the concentrator is analyzed subsequently, and the frequency point distribution is facilitated.

And inquiring whether a new concentrator without the distributed frequency points exists in the concentrator frequency point distribution table, and if so, specifically distributing the principle according to the concentrator position relation table.

The server "reads the concentrator field intensity table as required, for example, the field intensity table is updated once before channel allocation and network optimization. Before reading the field intensity meter of the concentrator, the server needs to firstly send a command for updating the field intensity meter of the concentrator to all the concentrators, and then waits for 240 seconds and reads the field intensity meter of the concentrator. The camera address allocation algorithm is mainly used for allocating a new camera to the concentrator, so that the field intensity table of the concentrator can be directly read before the algorithm is executed, and a concentrator updating field intensity table instruction does not need to be issued.

The task of calculating the working channel number of the concentrator and distributing the working channel number is timed triggering, the interval time can be configured, and the current engineering configuration is once every 5 minutes. The allocation of channels is related to the field strength table of the camera, i.e. to determine which concentrators are adjacent to which concentrator the channel numbers of adjacent concentrators are staggered as much as possible. Initial allocation is also this step.

Further, referring to fig. 7, calculating and assigning the number of the concentrator operating channel includes the following steps:

SS9) to select a concentrator;

SS10) determining whether the concentrator selected in step SS9) has allocated channels, if yes, executing step SS13), if no, initializing the use weight of each channel, wherein the smaller the weight is, the higher the availability is, the weight is greater than or equal to a threshold (the threshold is set according to actual needs, the threshold is 30000 in this embodiment), the unavailability is indicated, the channels allocated to other concentrators are marked as unavailable, and the weight of the allocated channels is initialized to 30000;

SS11), traversing and selecting an adjacent concentrator, wherein the adjacent concentrator means that the number of common cameras existing between two concentrators is larger than a set value (the set value is set according to actual needs, the set value is 0 in the embodiment), judging whether the adjacent concentrator has distributed channels, if so, adding a set value to the weight values of the upper and lower channels of the working channel of the adjacent concentrator (the set value is set according to actual needs, the set value is 8000 in the embodiment), adjusting the weight values of other adjacent channels according to the number of the common cameras, executing the step SS12), and if not, directly executing the step SS 12);

SS12) determining whether the last adjacent concentrator selected in step SS11) is the last adjacent concentrator, if not, returning to continue to execute step SS11), if yes, selecting the channel with the smallest weight from the channels with the weight less than the threshold (the threshold is set according to actual needs, the threshold is 30000 in this embodiment), if at least two channels with the smallest weight are available, selecting the channel with the largest number from the channels with the smallest weight to allocate to the concentrator, and executing step SS 13);

Referring to fig. 8, further, the method further includes triggering global network optimization periodically or manually; the global network optimization step comprises moving a camera with low photographing success rate, marking a non-movable camera, and iteratively calculating an optimization network, and specifically comprises the following steps:

SSS2) traversing to select a concentrator to be optimized;

SSS8), and the iteration number is initialized to 0;

SSS9) traversing to select a concentrator to be optimized;

SSS10) selects one neighboring concentrator in a traversal, where the neighboring concentrator means that the number of common cameras existing between two concentrators is greater than a set value (the set value is set according to actual needs, the set value is 2 in this embodiment), and if there is a camera number difference greater than a set value (the set value is set according to actual needs, the set value is 2 in this embodiment), and there is a movable camera, the mobile camera moves from more to less according to a set movement rule, the number of movements is increased by n, and the set movement rule includes no movement for which the history record is lower than the record, no movement for which the signal is weaker than the set value (the set value is set according to actual needs, the set value is-65 dBm in this embodiment), a camera with a strong signal is preferentially moved, and if it is possible to move.

Continuing to perform step SSS 11); otherwise, step SSS11 is executed directly);

SSS12) determining whether the selected one in step SSS9) is the last concentrator to be optimized, if not, returning to continue to execute step SSS9), if so, adding 1 to the iteration number, and determining to execute step SSS13 when the number of moves is 0 or the iteration number is greater than a set value (the set value is set according to actual needs, in this embodiment, the set value is 10), otherwise, starting a new round of zero clearing of the number of moves, and executing step SSS 9);

SSS14) issues an instruction to adjust the concentrator, and the network optimization is completed.

The initial weight of each channel is shown in the following table, and before the channel allocation calculation of each concentrator, the usage weight of each channel is initialized. The smaller the weight value is, the higher the usability is, and the weight value is more than or equal to 30000, the unavailability is indicated. This initialization weight table is configurable. In practical engineering, if some channels are relatively severely interfered, the initial weight value should be larger, which indicates that the channel is not preferred.

The channels already assigned to the other concentrators are marked as unavailable, i.e. the channel weights are modified to 30000. The following figure assumes that channel 33 has been assigned to "concentrator 0" and 28 has been assigned to "concentrator 1".

Polling the neighbor concentrators and adjusting the weight values of the adjacent channels according to the number of the cameras shared by the adjacent concentrators. Assuming the channel number of concentrator 2 in this round, the adjacency of concentrator 2 to other concentrators is as follows.

The number of adjacent nodes of concentrator 2 and concentrator 0 (32, 24), and the number of adjacent nodes of concentrator 2 and concentrator 1 (17, 11). From the weight calculation in the table below, it can be seen that the concentrator 2 can select the optimal channel number as 22.

The network optimization of the invention is divided into success rate optimization and global optimization. The success rate optimization algorithm triggering condition is as follows: and in the last 10 times of statistics of a certain camera, if the photographing success rate is less than 70%, triggering network optimization. This type of optimization is performed in a camera address assignment algorithm with an optimization success rate below 70% for cameras. Global optimization triggering conditions: a timed trigger or a manual trigger, and a global network optimization or a manual trigger is started at 23:00 (configurable) nights each day. At the moment, 3 overall parameters are considered in optimization, the number of cameras adjacent to the concentrator, the number of cameras administered by the concentrator and the photographing success rate of the cameras administered by the concentrator are required to be considered.

Network optimization is primarily concerned with the success rate of the current camera's shots and secondarily with the uniformity of the distribution. Iterative convergence conditions of the global network optimization algorithm are as follows: the number of adjacent concentrator cameras differs by less than 5 or there is no common camera available to adjust. If the optimization algorithm iterates for 10 rounds and the convergence condition is not reached, the optimization calculation process is forcibly ended. In fact, if the algorithm is normal, it is certain that the convergence condition can be reached soon, and if the 10 iterations do not converge yet, the algorithm can be considered to be vulnerable, and further optimization of the algorithm is needed.

And the concentrator adjacency relation table is calculated from the camera field intensity information table. The table counts the number of common cameras that are present between the two concentrators, including the total number and the number of (-65dBm) that satisfy the signal strength. The larger the number, the closer two concentrators are adjacent can be approximated. The closer the adjacent concentrators, the greater the distance the channel number should be assigned.

Referring to fig. 7, the calculation of the concentrator adjacency relation table includes the following steps:

SS1) to select a concentrator;

SS3) to select the next concentrator;

The protocol comprises two parts, namely GWIOT-B protocol and GWIOT-C protocol. Wherein the GWIOT-B protocol is used for wireless communication between the low power camera and the concentrator. The GWIOT-C protocol is used for communication between the concentrator and the communication server. A star-net structure is used between the low power cameras and the concentrator. The GWIOT-B protocol contains 34 working channels and 2 common channels. Each concentrator uses frequency division multiplexing of different working channels, which are uniformly distributed and managed by the communication server. The concentrator-managed low-power cameras are uniformly assigned and scheduled by the communication server. The low-power-consumption cameras send network access applications in a public channel, the communication server distributes the low-power-consumption cameras to proper concentrators after sensing the existence of the low-power-consumption cameras, and then the corresponding concentrators can configure the low-power-consumption cameras to enter own networks. The communication server sends an instruction to the concentrator to start the photographing process. After receiving the photographing instruction, the concentrator wakes up the low-power-consumption camera to take a photograph, then obtains photograph data by using a data transmission command of a GWIOT-B protocol, and then transmits the photograph to the communication server by using a related command of the GWIOT-C protocol.

As shown in fig. 1, the low power wireless photographing access and transmission protocol comprises two parts, which are GWIOT-B protocol and GWIOT-C protocol. Wherein the GWIOT-B protocol is used for wireless communication between the low power camera and the concentrator. The GWIOT-C protocol is used for communication between the concentrator and the communication server.

The physical layer of the GWIOT-B protocol comprises 34 working channels FCW 00-FCW 33, and 2 common channels FCC00 and FCC 01. Each channel is spaced by 1.1MHz, the modulation mode uses 4GFSK, and the internal modulation frequency offset is 87.5 KHz. The symbol rates 200Ksps, 350Ksps correspond to communication rates of 400Kbps and 700Kbps, respectively. The default rate for photo transmission is 700Kbps, the default maximum equivalent radiated power is less than 17dBm, and the out-of-band spurious is less than-36 dBm. A star-net structure is used between the low power cameras and the concentrator. Each concentrator uses frequency division multiplexing of different working channels, which are uniformly distributed and managed by the communication server.

The GWIOT-B protocol frame preamble uses a 32 byte 01 bit stream. The sync word fixed uses 2 bytes 0xC 693. The frame length uses 4 bytes, where the first 2 bytes represent the physical layer payload length and the last 2 bytes are the length value, inverted. The physical layer payload data is data whitened using a whitening algorithm. And performing CRC16 calculation on all data subjected to whitening of the physical layer load after the synchronization word by frame check, and arranging the calculation result in a big-end mode. All data in the GWIOT-B protocol are arranged using the small-end pattern, without special provisions. If the encryption function is turned on, the data of the physical layer payload needs to be encrypted using a symmetric encryption algorithm.

The GWIOT-B protocol does not include the Medium Access Control (MAC) protocol. After the low-power-consumption camera is accessed to the network, the medium access is initiated by the concentrator, and the low-power-consumption camera is accessed in a response mode, so that the problem of channel competition does not exist. When the common channel FCC00 sends a network access application command, the low-power camera may cause channel access conflict, and the random delay retransmission mode is used in the protocol to avoid

The GWIOT-B protocol network layer contains 14 commands. Respectively as follows: denying, confirming, network access application, network configuration, clock synchronization, reading state, response state, starting photographing, power control, field intensity refreshing, camera broadcasting, stopping working, rate control and data application.

When the low-power-consumption camera is not connected to the network, a network access application command is sent at a public channel FCC00 at random intervals of 10-13 seconds. Then waits 35 milliseconds for the concentrator's configuration network command on the common channel FCC 01. If no configuration network command is received within 35 milliseconds, then sleep mode is entered. The low power camera repeats this process until a configure network command is received. The concentrator receives the network access request command of the low power consumption camera, and if the low power consumption camera belongs to the management of the concentrator, the concentrator sends a network configuration command in a public channel FCC 01. The configuration network command contains information such as an operating channel, a maximum time slot, an operating time slot, a time slot time, a maximum operating time, a current system time, and the like of the low power consumption camera. After receiving the network configuration command of the concentrator, the low-power-consumption camera firstly synchronizes the self time slot timer once, then responds to the confirmation frame and then switches to the network access mode. After the low-power camera is connected to a network, the default transmitting power for picture transmission is the maximum power, and the default transmission rate is 700 Kbps.

After the low power consumption camera is connected to the network, the low power consumption camera wakes up once in the assigned working time slot every 5 seconds and waits for the command of the concentrator for 35 milliseconds in the assigned working frequency channel. If the command of the concentrator is received within 35 milliseconds, the time slot timer of the concentrator is synchronized once, and then the command sent by the concentrator is executed. If the low-power-consumption camera does not receive any command of the concentrator for 8 minutes continuously, the low-power-consumption camera needs to be separated from the network access mode and resends the network access application command to apply for network access.

The concentrator broadcasts a clock synchronization command on the operating channel every 3.5 minutes. After receiving the clock synchronization command, the low-power-consumption camera firstly synchronizes the self time slot timer once and then immediately enters a sleep mode. The clock synchronization command is only used for time slot timer synchronization of the low power consumption camera and maintaining the on-network state of the low power consumption camera.

The concentrator broadcasts a field strength refresh command on the operating channel every 10 minutes. The low power camera receives the field strength refresh command and broadcasts it once on the common channel FCC00 using the camera broadcast command. The camera broadcast command contains information such as battery voltage, operating state, firmware version, transmit power, communication rate, etc. of the low power camera. For refreshing the field strength recordings of the low power camera at other concentrators, etc.

If the concentrator does not receive information of battery voltage, operating state, firmware version, transmission power, communication rate, etc. of the low power consumption camera within 20 minutes, the information of the low power consumption camera is directly read using a read status command and the low power consumption camera responds using a response status command.

The state transition for low power camera auto power control is shown in fig. 10. The concentrator judges the signal quality of the low-power-consumption camera according to the success rate of picture transmission, the packet loss rate of picture transmission and the signal strength during picture transmission. If the intensity of the low-power camera transmitting signal is strong, the concentrator can use the power control command to reduce the wireless transmitting power of the low-power camera, so as to achieve the purpose of reducing the average working current of the low-power camera. If the strength of the signal transmitted by the low-power-consumption camera is very weak, which causes the packet loss rate of the photo transmission to be too high, the concentrator can use the power control command to increase the wireless transmission power of the low-power-consumption camera, thereby reducing the retransmission times of the photo data packet and the time of the photo transmission.

The state transition for low power camera auto rate control is shown in fig. 10. If the low-power camera still has a higher packet loss rate or a higher failure rate of picture transmission when transmitting pictures under the maximum transmission power, the concentrator can use the rate control command to reduce the data rate of the wireless communication of the low-power camera, thereby improving the link budget of a wireless channel and achieving the purpose of stable transmission. If the communication quality of the low-power-consumption camera is good at a low speed and the signal strength reaches a threshold value, the concentrator can use a speed control command to improve the data speed of the wireless communication of the low-power-consumption camera, so that the picture transmission time is shortened, and the aim of reducing the average working current of the low-power-consumption camera is fulfilled.

The low power camera cannot take normal pictures at night or in the absence of light. If it is explicitly known that the low power camera does not need to take a picture for a certain period of time, the concentrator can use the stop-work command to set the period of non-operation of the low power camera. The low power camera enters a deep sleep mode during the inactive time period without executing any instruction, thereby further reducing the average standby current. After the low-power camera is awakened from the deep sleep mode, the low-power camera needs to reapply for network access.

After receiving a photographing starting command sent by the concentrator, the low-power-consumption camera firstly responds to the confirmation frame, then turns on a power supply of the image sensor, initializes the image sensor and completes lens focusing, and then captures a picture from a video stream. The low power camera uses application data commands to packetize the photos to the concentrator, up to 5KB per packet of data. If some data packets received by the concentrator from the photos are lost, the concentrator can use the application data command to apply for data packet retransmission until all data packets are transmitted or the time is over.

The GWIOT-C protocol is used for communication between the concentrator and the communication server. The communication server is used as a TCP server side, and the concentrator is used as a TCP client side. After the concentrator is powered on or reset, an uplink communication interface is initialized, and then TCP connection is initiated to the communication server. After the TCP connection is successfully established, the communication server firstly reads information such as the identity ID, the communication public key, the identity certificate and the like of the concentrator. If the identity certificate passes the verification, the concentrator is allowed to access, and if the identity certificate fails to verify, the TCP connection of the concentrator is disconnected, so that illegal connection access or pirate equipment access is prevented.

The frame length of the GWIOT-C protocol frame is arranged in a big end mode, CRC16 verification is carried out in a big end mode, and other special notes indicate that data are arranged in a small end mode. After the concentrator initiates the TCP connection, the communication server may read the information of the concentrator using the wildcard address, which is 0 xaaaaaaaaaa.

The GWIOT-C protocol contains 23 commands, which are: denying, confirming, reading information, responding information, setting a concentrator, distributing a camera, issuing an upgrade file, starting real-time photographing, reading new photo information, responding the new photo information, deleting a new photo, reading a packet of photo data, responding a packet of photo data, setting uplink network parameters, reading uplink network parameters, responding uplink network parameters, setting an off-time period, reading an off-time period, responding an off-time period, updating a field intensity table of the concentrator, uplink heartbeat response and concentrator reset.

The concentrator operating channel allocation method is shown in fig. 7. When the concentrator receives commands such as network access application of the low-power-consumption camera, the field intensity value of the signal transmitted by the low-power-consumption camera is recorded. The communication server reads the field intensity record tables of all the concentrators by using the information reading command at intervals, and then calculates the adjacent relation among the concentrators. If the concentrator does not distribute the channel number, the weight of each channel is calculated according to the rule, the lower the weight is, the higher the priority is, then a channel with the lowest weight is selected, and the concentrator is distributed with the channel by using the command of setting the concentrator. If the weights of a plurality of channels are the same, the channel with the large channel number is selected to be distributed to the concentrator.

And the communication server reads the field intensity recording tables of all the concentrators by using the information reading command at intervals, and judges whether the low-power-consumption cameras in the field intensity recording tables are allocated to the specific concentrator management. If the low power consumption camera is not assigned, the low power consumption camera is assigned to an appropriate concentrator according to the principle of signal strength and equalization, and then the communication server issues the address of the low power consumption camera to the concentrator using an assign camera command. The concentrator, upon receiving the assign camera command, acknowledges or denies the frame.

On the communication server, the off-time of the low power consumption camera may be configured, during which time the low power consumption camera may enter deep sleep. The communication server uses the command of setting the non-operation time period to set the non-operation time to the concentrator, and then the concentrator controls the low-power consumption camera to enter a deep sleep mode. The communication server may read the time parameter issued to the concentrator using a read off time period command, and the concentrator returns the time parameter using a reply off time period command.

At the communication server, the upstream network parameters of the concentrator can be configured. The communication server uses the command of setting the uplink network parameters to set the uplink network parameters in the concentrator. The communication server can use the command for reading the uplink network parameter to read the network parameter sent to the concentrator, and the concentrator uses the command for responding the uplink network parameter to return the network parameter. The communication server may remotely reset the concentrator using a concentrator reset command, enabling validation of the newly configured upstream network parameters.

To maintain and detect a TCP connection between the communication server and the concentrator, the communication server sends an uplink heartbeat command to the concentrator every 60 seconds. After receiving the uplink heartbeat command, the concentrator responds with an uplink heartbeat response command. If the concentrator does not receive any command from the communication server for 180 seconds, it can be determined that the TCP connection has failed and the concentrator needs to actively re-establish the TCP connection.

When the timing photographing time configured in the communication server arrives or a photographing instruction of the application server is received, the photographing instruction can be issued to the concentrator by starting the real-time photographing command. The photographing instruction may be transmitted in a plurality of consecutive pieces. After the concentrator receives the command of starting the real-time photographing, the photographing command is stored in the command queue and is executed one by one. At the moment, the communication server continuously inquires whether the photographing process is finished or not by reading a new photographing information command until the photographing is successful or overtime. If the concentrator responds to the new photo information command, the completion of the photographing process is prompted, and information such as the size of the photo is given. At this time, the communication server can read the photo data packet by reading a packet of photo data command, and the size of the data packet is determined by the communication server, so the communication server can also read the whole photo data packet by packet. And after the communication server finishes reading the photos, deleting the photos stored in the concentrator by sending a command of deleting the new photos.

The low-power wireless photographing transmission system comprises three parts, namely a low-power camera, a concentrator and a communication server.

When a concentrator initiates TCP connection, the switching center reads the concentrator address, fills the concentrator address into the form one by one and allocates a working channel number.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-power consumption wireless transmission system of shooing which characterized in that: the system comprises a low-power-consumption camera, a concentrator and a communication server, wherein the low-power-consumption camera is communicated with the concentrator through a wireless network, the concentrator is communicated with the communication server through a remote communication network, the concentrator is used for being in charge of wireless access and photo data transmission of the low-power-consumption camera, and the communication server is used for being in charge of identity authentication, connection management, distribution of working channels, distribution and scheduling of the low-power-consumption cameras in the whole network, load balancing of the concentrator, issuing of photographing instructions and collection and uploading of photos.

2. The system of claim 1, wherein: the low power consumption camera comprises an MCU module, a power supply circuit, an external storage circuit, an image sensor and a wireless transceiving chip, the power circuit is used for supplying power to the low-power consumption camera, the external storage circuit, the image sensor and the wireless transceiving chip are respectively connected with the MCU module, the MCU module drives an external storage circuit through an I2C interface, the external storage circuit is used for saving factory configuration information of the camera, the image sensor uses a clock signal provided by an MCU module, the MCU module configures the image sensor and completes the focusing function through an I2C interface, the photo data is captured through the DCMI interface, the MCU module controls the wireless transceiving chip by using the SPI interface, when the low-power-consumption camera is not connected to the network, a network access application is sent to the concentrator at regular time, and after the low-power-consumption camera is connected to the network, the wireless transceiving chip wakes up at regular time to wait for the management and photographing command of the concentrator.

3. The system of claim 2, wherein: the power supply circuit comprises a DC-DC voltage stabilizing circuit, a first LDO voltage stabilizer, a second LDO voltage stabilizer and a third LDO voltage stabilizer, wherein the input end of the DC-DC voltage stabilizing circuit is connected with an input power supply, the output end of the DC-DC voltage stabilizing circuit is connected with a VCC power supply terminal through a first MOS switch, the input end of the first LDO voltage stabilizer is connected with the input power supply, the output end of the first LDO voltage stabilizer is connected with the VCC power supply terminal through a Schottky diode, and the VCC power supply terminal is used for outputting VCC voltage to supply power to the MCU module; the second LDO voltage stabilizer is used for converting VCC voltage into 2.8V to supply power to the image sensor, the third LDO voltage stabilizer is used for converting VCC voltage into 1.5V to supply power to the image sensor, the DC-DC voltage stabilizing circuit, the second LDO voltage stabilizer and the third LDO voltage stabilizer are all in a turn-off state when not taking a picture, and the power supply is turned on only when needed;

the power supply circuit further comprises a battery voltage measuring circuit, the input power supply adopts a battery, the input end of the battery voltage measuring circuit is connected with the input power supply through a second MOS switch, and the output end of the battery voltage measuring circuit is connected with the ADC port of the MCU module and used for measuring the battery voltage and judging the battery capacity.

4. The system of claim 2, wherein: the external storage circuit comprises an EEPROM module, the EEPROM module is connected with the MCU module, and a third MOS switch is arranged between the EEPROM module and VCC voltage and used for switching on or off the power supply of the EEPROM.

5. The system of claim 1, wherein: the concentrator comprises an MCU module, a power supply circuit, an external storage circuit, a wireless communication circuit and an uplink communication interface circuit, wherein the power supply circuit is used for supplying power to the concentrator; the external storage circuit is used for storing configuration, archives, network operation information and caching photo information.

6. The system of claim 5, wherein: the external storage circuit comprises FLASH and SDRAM, the FLASH is driven by an SPI interface and is used for storing factory information, equipment configuration, camera files and network operation information, and the SDRAM is driven by an FMC interface and is used for caching photo information and the like.

7. The system of claim 5, wherein: the wireless communication circuit comprises two paths of wireless communication interfaces, wherein one path is used for high-speed communication, an ISM frequency band and a private access protocol are used, the access of a low-power-consumption camera is supported, and the other path is used for long-distance low-speed communication and is reserved for the expansion of other applications.

8. The system of claim 5, wherein: the uplink communication interface circuit comprises one or more of an Ethernet interface, an optical fiber communication interface, a WiFi interface and a 4G/5G/private network communication interface.

9. The system of claim 1, wherein: the communication server comprises a remote communication interface and an application service interface, wherein the remote communication interface is used as a TCP server side, allows the concentrator device to be accessed in a TCP mode and completes network management and data transmission by using a private protocol, and the application service interface is used for exchanging data with the application server by using a TCP or Redis mode.

10. The system of claim 1, wherein: the communication server managing a plurality of concentrators, each concentrator managing a plurality of low-power-consumption cameras; each concentrator uses a different operating channel, the channel number of which is uniformly assigned by the communication server.