CN107148069B

CN107148069B - Self-networking and low-power-consumption data collection method of tree sensor network

Info

Publication number: CN107148069B
Application number: CN201710181152.XA
Authority: CN
Inventors: 蔡昕哲; 顾敏明; 潘海鹏
Original assignee: Zhejiang Sci Tech University ZSTU
Current assignee: Shenzhen Star Instrument Co ltd
Priority date: 2017-03-24
Filing date: 2017-03-24
Publication date: 2020-07-10
Anticipated expiration: 2037-03-24
Also published as: CN107148069A

Abstract

The invention discloses a self-networking and low-power consumption data collection method of a tree-type sensor network.A sensor node is in wireless communication with a coordinator, the coordinator is in serial port communication with a relay gateway, the sensor node is responsible for measuring various environmental data on site and sending the data to the coordinator in a wireless way, and on one hand, the coordinator is in communication with the sensor node in a wireless way, is responsible for establishing the sensor network and collecting the measured data of the sensor node; on the other hand, the relay gateway is communicated with the serial port and is responsible for forwarding the measurement data of the sensor node to the relay gateway and receiving the instruction of the relay gateway; the relay gateway has the function that after the measured data of each node are collected in the relay gateway, the data are fused by the gateway, and finally the data are sent to the monitoring server through the network.

Description

Self-networking and low-power-consumption data collection method of tree sensor network

The technical field is as follows: the invention relates to a wireless sensor network, in particular to data collection of the wireless sensor network.

Technical background:

in recent years, with the rapid development of the internet of things, wireless sensor networks begin to play more and more important roles in the lives of people. The wireless sensor network integrates multiple fields such as a sensor technology, an embedded computing technology, a modern network, a wireless communication technology, a distributed information processing technology and the like, and is widely applied to multiple application scenes such as agricultural cultivation, ecological monitoring, industrial facility detection, natural disaster prediction, intelligent traffic control, intelligent home and military occasions and the like.

The common topological structures of the wireless sensor network mainly comprise star-shaped, tree-shaped, mesh-shaped and the like topological structures. The tree-type sensor network is more suitable for the application field of wireless sensor networks which have fixed data acquisition period, small data transmission quantity, low frequency, large communication range and need regional management compared with other topological structures, but the traditional tree-type sensor network has poor dynamic topological capability in networking, the sensor nodes depend on the nodes of the previous stage, once the nodes of the previous stage fail, the nodes of the sensor nodes below the previous stage are separated from the network, meanwhile, the traditional tree-type sensor network usually adopts two aggregation methods in data aggregation, namely, the sensor nodes are dormant from low power consumption according to fixed time intervals, and wake up randomly for a period of time after the environmental parameters are measured, actively sending data; and secondly, the sensor node is awakened from dormancy according to a fixed time interval, waits for a convergence instruction after the environmental parameter measurement is completed, and passively sends data. The former is easy to generate the concurrency of a plurality of node data, which causes message collision and needs to be retransmitted for a plurality of times, thus wasting redundant energy consumption, and the latter is used for ensuring that the node can receive the collection instruction, the node needs to be awakened in advance for a long time, thus wasting redundant energy consumption.

The invention content is as follows:

aiming at the problems, the invention provides a self-organizing network and low-power-consumption data collection method of a tree-type sensor network (a tree network is formed by a sensor node, a coordinator, a relay gateway and a router) which meets the actual requirements.

A self-networking and low-power consumption data collection method of a tree-type sensor network is characterized in that a sensor node is in wireless communication with a coordinator, the coordinator is in communication with a relay gateway through a serial port, the sensor node is responsible for measuring various environmental data on site and sending the data to the coordinator in a wireless manner, and the coordinator is in communication with the sensor node in a wireless manner on one hand and is responsible for establishing the sensor network and collecting the data measured by the sensor node; on the other hand, the relay gateway is communicated with the serial port and is responsible for forwarding the measurement data of the sensor node to the relay gateway and receiving the instruction of the relay gateway; the relay gateway has the function that after the measured data of each node are collected in the relay gateway, the data are fused by the gateway, and finally the data are sent to the monitoring server host through the network;

the working steps of the sensor node comprise a first network access stage, a second network access stage and a data measurement and transmission stage; the method comprises the following specific steps:

1) and after the node is powered on, hardware configuration is initialized.

2) Reading self node address information in an EEPROM in a controller chip, wherein the default address is 0X 0000;

3) whether the node address is 0X0000 or not is judged, if yes, the node is judged to be a new node which is not networked, and a stage that the node is accessed to the network for the first time is entered, namely, steps 4) -7); otherwise, judging whether the node is a new node, and entering the step 8);

a first network access stage:

4) broadcasting a new node request network access instruction in a channel 0;

5) switching to a channel 0 receiving state, waiting for reply, wherein the waiting time is T _ Wait, judging whether a new node access permission instruction replied by the coordinator is received, if so, entering a step 6), and if not, returning to the step 4);

6) reading a new node network access permission instruction, recording a node address distributed by the coordinator, writing the node address into an EEPROM, recording a use channel, marking the self state as a normal state, and marking the network access just now;

7) replying a node confirmation network access instruction to the current coordinator in the channel 0, and entering the step 8);

8) judging whether the self state is a fault state, if so, entering a network re-access stage, namely steps 9) to 18), and otherwise, entering a data measurement sending stage, namely steps 19) to 28);

and a network re-access stage:

9) judging whether the broadcasting frequency of the network access request instruction of the original node reaches the specified frequency, if so, entering a step 14), otherwise, entering a step 10);

10) broadcasting an original node network access request instruction in a channel 0;

11) switching to a channel 0 receiving state, waiting for replying, wherein the waiting time is T _ Wait, judging whether an original node network access allowing instruction replied by the original coordinator is received, if so, entering a step 12), and if not, entering a step 13);

12) marking the self as a normal state, marking the network access, recording a use channel in the instruction, and returning to the step 8);

13) randomly waiting for a period of time, and returning to the step 9);

14) broadcasting a network access request instruction of a node to be managed in a channel 0;

15) switching to a channel 0 receiving state, waiting for a reply, wherein the waiting time is T _ Wait, judging whether a network access instruction of the node to be managed replied by the coordinator is received, if so, entering a step 16), and if not, entering a step 18);

16) reading an instruction, recording a use channel, marking the self state as a normal state, and marking the network access just now;

17) replying a network access confirmation instruction of the node to be managed to the hosting coordinator in the channel 0, and returning to the step 8);

18) waiting for 30 seconds, resetting the broadcast times of the network access request instruction of the original node, and returning to the step 9);

data measurement and transmission stage:

19) judging whether the network is just accessed, if so, entering a step 20), and otherwise, entering a step 22);

20) assigning all the measurement data to 0;

21) switching to a using channel receiving state, waiting for a data acquisition instruction sent by a coordinator in the existing network, and entering step 24 after receiving the instruction);

22) turning on a power supply of the sensor module, and measuring environmental parameters;

23) closing a power supply of the sensor, waking up the wireless module, switching to a channel receiving state, waiting for a coordinator instruction, wherein the waiting time is T _ Wait _ Collect, judging whether a data acquisition instruction sent by the coordinator is received, and if so, entering step 24), otherwise, entering step 28);

24) recording a time interval T _ Collect for collecting data next time, a total number N _ Error of fault nodes and a number N _ Error _ Add of newly-added fault nodes, calculating the awakening timing time T _ Wake of a low-power-consumption processor next time, receiving the awakening time T _ Wait _ Collet of a wireless module, receiving the awakening time T _ Wait _ Collet of the wireless module, and timing the timer T _ Wake;

25) sending a measurement data instruction to a coordinator sending node by using a channel;

26) closing all unused resources and entering dormancy;

27) after the timing time T _ Wake is up, the timer interrupts to Wake up the low-power-consumption processor, and the step 8) is returned;

28) marking the self fault state and returning to the step 8);

the working step of the coordinator comprises a coordinator network access stage, a broadcast monitoring stage and a data collection stage;

the method comprises the following specific steps:

the coordinator enters a network stage:

(1) initializing hardware configuration after the coordinator is powered on;

(2) sending a coordinator request network access instruction to a gateway;

(3) after receiving an approving coordinator network access instruction replied by the gateway, recording a coordinator address, the number of original nodes and a use channel, and marking all the nodes as fault states;

(4) broadcasting a coordinator channel selection instruction on a channel 0;

(5) switching to a channel 0 receiving state, waiting for reply, wherein the waiting time is T _ Wait, judging whether a coordinator channel occupation instruction replied by other coordinators is received or not, if so, judging that the channel is occupied, entering a step (6), and if not, judging that the channel is available, entering a step (9);

(6) judging whether the sending times of the coordinator channel selection instruction is equal to the sum of the channels minus 1 time, if so, judging that the channel selection fails, and entering a step (7), otherwise, entering a step (8);

(7) sending a coordinator channel selection failure instruction to the gateway, clearing the number of times of sending the coordinator channel selection instruction after waiting for a period of time, and returning to the step (4);

(8) changing the selected channel in the coordinator channel selection instruction, and returning to the step (4);

(9) determining that a coordinator Channel selection success instruction is sent to a gateway by using a Channel _ Used;

(10) after receiving a successful network establishment command replied by the gateway, updating the timer timing time T _ Collect and timing by the timer;

(11) switching to a channel 0 receiving state, and monitoring broadcast;

(12) judging whether the timer time of the timer is up, if not, entering a monitoring broadcast phase, namely steps (13) - (27), otherwise, entering a data collection phase, namely steps (28) - (39);

and a broadcast monitoring stage:

(13) judging whether an instruction broadcasted by a node or other coordinators is received, if so, entering a step (14), otherwise, returning to the step (12);

(14) reading the instruction, judging the type of the instruction, entering the step (15) if the instruction is a coordinator channel selection instruction, and entering the step (19) if the instruction is a node network access request instruction;

process other coordinator channel selection instruction subflow:

(15) judging whether a channel selected in the coordinator channel selection instruction is the same as a self-used channel, if so, judging channel collision, and entering a step (16), otherwise, entering a step (17);

(16) replying a coordinator channel occupation instruction in a channel 0;

(17) judging whether a node address first byte and the address of a coordinator sending a coordinator channel selection instruction exist in the self hosting node, if so, entering the step (18), otherwise, returning to the step (11);

(18) marking the managed node as a fault state, sending a node fault instruction to the gateway, and returning to the step (11);

the sub-process of the processing node requesting the network access instruction comprises the following steps:

(19) reading the instruction, judging the type of the instruction, and entering the step (20) if the instruction is a new node network access request instruction; if the original node requests a network access instruction, entering a step (23); if the original node requests a network access instruction, entering a step (21), and if the original node requests the network access instruction, entering a step (25);

(20) allocating node addresses, and sending a new node network access allowing instruction to the nodes in a channel 0;

(21) switching to a channel 0 receiving state, waiting for a reply, wherein the waiting time is T _ Wait, if a node confirmation network access instruction (containing a node address) is received, entering a step (22), and if not, returning to the step (11);

(22) updating the Node number S _ Node +1, marking the Node as a normal state, sending a new Node network access instruction to the gateway, and returning to the step (11);

(23) sending an instruction for allowing the original node to access the network to the node in a channel 0;

(24) marking the node as a normal state, sending an original node network access instruction to the gateway, and returning to the step (11);

(25) sending a network access instruction of a node to be managed to the node in a channel 0;

(26) switching to a channel 0 receiving state, waiting for a reply, wherein the waiting time is T _ Wait, if a network access instruction confirmed by a node to be managed is received, entering a step (27), and if not, returning to the step (11);

(27) recording the address of the hosting node, marking the node as a normal state, and sending a network access instruction of the node to be hosted to the gateway; returning to the step (11);

a data collection stage:

(28) after the timer reaches the set time, sending a command for acquiring the time of next data acquisition to the gateway;

(29) after receiving a data acquisition time instruction which is replied by the gateway and informs of next time, updating the timer timing time T _ Collect, and timing by the timer;

(30) reading the address and the state of the first node, and clearing the total number N _ Error of the fault nodes and the number N _ Error _ Add of newly-added fault nodes;

(31) if the node state is normal, entering step (32), otherwise, entering step (36);

(32) sending a data acquisition instruction to a node on a Used Channel _ Used;

(33) switching to a receiving state of using a Channel _ Used, waiting for replying, wherein the waiting time is T _ Wait, if a node sends a measurement data instruction, entering a step (34), and if not, entering a step (35);

(34) recording measurement data, sending a coordinator data transmission instruction to the gateway, waiting for a timing time, and entering a step (37);

(35) marking the nodes as fault states, updating the total number of the fault nodes N _ Error to be N _ Error +1, adding the number of newly-added fault nodes N _ Error _ Add to be N _ Error _ Add +1, sending a node fault instruction to the gateway, and entering a step (37);

(36) updating the total number of the fault nodes N _ Error to be N _ Error + 1;

(37) whether the node is the last node, if yes, entering a step (38), otherwise, entering a step (39);

(38) sending a data acquisition completion instruction of the current round to the gateway, and returning to the step (11);

(39) and reading the address and the state of the next node, and returning to the step (31).

Compared with the traditional tree-shaped sensor network, the invention has the advantages that:

1. the fixed use channel 0 is defined in broadcasting between the sensor node and the coordinator, and is distinguished from the network communication channel between the sensor node and the coordinator at other stages. The method ensures that the coordinator channel selection instruction and the sensor node network access instruction which need to be broadcasted only need to be broadcasted in a single channel without scanning a plurality of channels, reduces the complexity of the channel selection process of the coordinator and the network access process of the sensor node, and avoids the extra energy consumption caused by scanning a plurality of channels in the network access process of the sensor node, thereby prolonging the service life of the network.

2. When the coordinator fails and is disconnected for a short time, the connected sensor nodes can automatically re-access the network. When the coordinator fails and is disconnected for a long time, the connected sensor nodes can be accessed to the network established by other coordinators on the premise of keeping the original network topology structure information, so that the condition that the sensor node measurement data obtained by a user is lost due to the fault of the coordinator is greatly reduced, and the integrity of the measurement data is optimized.

3. When a coordinator with a fault is on-line and reestablishes a network, the original node can quickly return to the network established by the coordinator, including the sensor nodes which are accessed to other coordinator networks, and can also quickly exit the existing network and return to the network established by the original coordinator. Meanwhile, the sensor node is on line again when a fault occurs, and can quickly return to the original network. Both ensure the stability of the network topology, so that the topology of the network is not damaged due to the fault of the coordinator or the sensor node.

Description of the drawings:

FIG. 1 is a diagram of a sensor node hardware architecture.

Fig. 2 is a hardware configuration diagram of the coordinator.

Fig. 3 is a diagram of a tree network architecture.

Fig. 4 is a general flow chart of the sensor node operation.

Fig. 5 is a flow chart of a stage of a node accessing a network for the first time.

Fig. 6 is a flow chart of a node re-network-entry stage.

Fig. 7 is a flow chart of a node data measurement transmission phase.

Fig. 8 is a general flow chart of the coordinator operation.

Fig. 9 is a flow chart of coordinator network entry.

Fig. 10 is a flow chart of the coordinator listening for a broadcast phase.

Fig. 11 is a sub-flow of the coordinator processing other coordinator channel selection instructions.

FIG. 12 is a sub-flow diagram of a coordinator processing node requesting a network entry instruction.

FIG. 13 is a flow chart of the coordinator data aggregation phase.

The specific implementation mode is as follows:

the following further illustrates the methods and principles of the present invention in connection with examples and the accompanying drawings.

The sensor node and the coordinator are in wireless communication through 433M, and the coordinator is in serial communication with the relay gateway.

Sensor node (node for short): and the system is responsible for measuring various environmental data in the field and wirelessly transmitting the data to the coordinator through 433M.

The sensor node is composed of a power supply module, a 433M wireless module, a low-power consumption processor and a sensor module, and a hardware structure diagram is shown in fig. 1.

The power module supplies power to the other three modules, and the low-power processor can cut off the power supply of the sensor module. Data transmission is carried out between the low-power-consumption processor and the 433M wireless module through an SPI bus, and the low-power-consumption processor and the sensor module carry out data transmission through an IIC bus or an ADC according to different sensors.

The coordinator: on one hand, the sensor node wirelessly communicates with the sensor node through 433M, and is responsible for establishing a sensor network and acquiring measurement data of the sensor node. And on the other hand, the system is communicated with the relay gateway through a serial port and is responsible for forwarding the measurement data of the sensor node to the relay gateway and receiving the instruction of the relay gateway.

The coordinator is composed of a power module, a 433M wireless module, a low-power consumption processor and a sensor module, and a hardware structure diagram is shown in FIG. 2.

Wherein, the power module supplies power for other two modules. Data transmission is carried out between the low-power processor and the 433M wireless module through the SPI bus.

Relay gateway (gateway for short): after the measured data of each node is collected in the relay gateway, the data are fused by the gateway, and finally the data are sent to the monitoring server host through the network.

The structure of the tree network formed by the sensors, the coordinator, the relay gateway and the monitoring server host is shown in fig. 3.

The monitoring server host serves as a first layer of the tree network, each relay gateway corresponds to one coordinator and serves as a second layer of the tree network, and the sensor nodes serve as a third layer of the tree network.

Name interpretation:

if the node A does not join any nodes of the network, the node A is called a new node. When a new node a is added to the network of coordinator a, node a is said to be the existing node of coordinator a, and coordinator a is the existing coordinator of node a. When the existing node A is disconnected from the network due to the fault, the node A is called as the original node of the coordinator A, and the coordinator A is the original coordinator of the node A. When an original node a of the coordinator a joins the network of the coordinator B, the node a is called a hosting node of the coordinator B, the coordinator B is called a hosting coordinator of the node a, and the node a is called a hosted node of the coordinator a (belonging to the category of the original node).

The operation state of the sensor node is divided into two states: a state of no networking or networking but disconnection from the coordinator (referred to as a fault state for short); networking and connecting with the coordinator in a normal state (referred to as a normal state for short).

The response waiting time after the coordinator and the node send data outwards is T _ Wait, and the coordinator and the node do not Wait after overtime. The waiting response time T _ Wait is determined according to the time required by a single response in practical application.

The node is accessed to the network for the first time and is accessed to the network again, the wireless channel is a channel 0 (broadcast channel), and the wireless channel is a use channel of the corresponding network in the data measurement and transmission stage.

Sensor node workflow: the method mainly comprises a first network access stage, a second network access stage and a data measurement and transmission stage.

Note 1: the nodes only receive the coordinator instruction of which the node address accords with the self address in the instruction. It is an exception that only new nodes that are not networked receive the allow networking command.

Note 2: in the broadcast monitoring stage, the coordinator receives and transmits commands and uses a channel 0 (broadcast channel); in the data gathering stage, the coordinator sends and receives instructions to use the use Channel _ Used selected in the network access stage of the coordinator.

1) And after the node is powered on, hardware configuration is initialized.

2) And reading self node address information (the default address is 0X0000) in the EEPROM in the controller chip.

3) Is the node address 0X 0000? If yes, judging that the node is a new node which is not networked, and entering a stage that the node accesses the network for the first time (steps 4) -7)). Otherwise, judging that the node is not a new node, and entering the step 8).

First access network stage (steps 4) -7)):

4) a new node request network entry command (containing the node's address and sensor class) is broadcast on channel 0 (broadcast channel).

5) Switch to channel 0 receive state, Wait for reply, Wait time T _ Wait, whether receive the command (including the assigned node address and channel used) of coordinator reply to allow new node to access network? If so, go to step 6). Otherwise, returning to the step 4).

Note 1: the waiting time T _ Wait is determined according to the time required by the 433M radio module to answer a single time actually adopted.

Note 2: the node address (2 bytes) is composed of a gateway address (1 byte) and a network access sequence number (1 byte). This has the advantage that the network configuration information, i.e. the gateway address and the network number of the connection, can be known from the node address.

6) And reading a network access permission instruction of the new node, recording the node address distributed by the coordinator, writing the node address into an EEPROM, and recording the use channel. And marking the self state as a normal state and marking the network access just now.

Note 1: the node address is written into the EEPROM to ensure that the original network structure information can still be maintained after the node is powered off.

Note 2: the channel is not written into the EEPROM because the coordinator fails to power down, the channel is required to be reselected to establish a network after being powered up again, and it is meaningless to write the channel in the EEPROM.

7) Replying the node confirmation network-accessing command (containing the node address) to the current coordinator in the channel 0. Step 8 is entered.

8) Is the self status a fault status? If so, enter the re-access network phase (steps 9) -18)), otherwise enter the data measurement transmission phase (steps 19) -28)).

Re-access network phase (steps 9) -18)):

(attempt to connect the original coordinator)

9) Is it determined whether the number of times of broadcasting of the original node request for a network access command (including the address of the node and the type of the sensor) reaches a predetermined number (which can be set as required)? If yes, go to step 14), otherwise go to step 10).

10) And broadcasting a network access request instruction (including the address and the sensor category of the node) of the original node in the channel 0.

11) Switch to channel 0 reception state, Wait for reply with a Wait time T _ Wait, whether the original coordinator received a command (including node address and channel used) to allow the original node to access the network, which was replied by the coordinator? If so, step 12) is entered. Otherwise, go to step 13).

12) Marking the self as a normal state, marking the network access just now, and recording the use channel in the command. Return to step 8).

13) Randomly waiting for a period of time and returning to step 9).

(request other coordinator to host)

14) And broadcasting a network access request instruction (including the address and the sensor category of the node) of the node to be managed in the channel 0.

15) Switch to channel 0 receive state, Wait for reply with a Wait time T _ Wait, whether a coordinator replies with an allow to host node network access command (including node address and channel used)? If so, step 16) is entered. Otherwise, step 18) is entered.

16) Reading the instruction and recording the used channel. And marking the self state as a normal state and marking the network access just now.

17) And replying an confirmed network access instruction (containing a node address) of the node to be managed to the management coordinator in a channel 0. Return to step 8).

18) And waiting for 30 seconds (set according to needs), and clearing the broadcasting times of the network access request instruction of the original node. Return to step 9).

Data measurement transmission phase (steps 19) -28)):

19) determine if a network has just been accessed? If yes, step 20) is entered, otherwise step 22) is entered.

20) All measurement data are assigned a value of 0.

Note: the first data transmission phase after accessing the network is only for time synchronization with the coordinator and does not measure the environment data.

21) And switching to a channel receiving state, and waiting for a data acquisition instruction (comprising a node address, a next data acquisition time interval T _ Collect, a total number of failed nodes N _ Error and a number of newly-added failed nodes N _ Error _ Add) sent by a coordinator in the existing network. After receiving the command, the process proceeds to step 24.

Note: the reception status waits all the time because the time between the node just accessed the network and the coordinator is not synchronized.

22) And (4) turning on a power supply of the sensor module, and measuring the environmental parameters.

23) And turning off the power supply of the sensor. And waking up the wireless module. Switch to the use channel reception state, Wait for the coordinator command, Wait time T _ Wait _ Collect, receive the data acquisition command sent by the coordinator? If so, go to step 24), otherwise go to step 28).

24) Recording the time interval T _ Collect for collecting data next time, the total number N _ Error of fault nodes and the number N _ Error _ Add of newly-added fault nodes, and calculating the awakening timing time T _ Wake of the low-power-consumption processor next time, namely T _ Collect-T _ Measure- (N _ Error _ Add) T _ Wait). After the wireless module wakes up, the wireless module receives a waiting time length T _ Wait _ Collect which is T _ Wait + N _ Error T _ Wait. The timer times T _ Wake.

Note: t _ Measure is the sum of the time required by the sensors on the nodes to Measure data and is determined by the types and the number of the sensors owned by the actual nodes.

25) The measurement data command (containing the node address and the measurement data) is sent to the coordinator sending node by using the channel.

26) And closing all unused resources and entering dormancy.

27) And after the timing time T _ Wake is up, the timer is interrupted to Wake up the low-power-consumption processor. Return to step 8).

28) And marking the self fault state and returning to the step 8).

The coordinator work flow comprises the following steps: the method mainly comprises a coordinator network access stage, a broadcast monitoring stage and a data collection stage.

Note 1: in the broadcast monitoring stage, the coordinator receives and transmits commands and uses a channel 0 (broadcast channel); in the data gathering stage, the coordinator sends and receives instructions to use the use Channel _ Used selected in the network access stage of the coordinator.

1. After the coordinator is powered on, hardware configuration is initialized.

Coordinator network entry stage (steps 2-12):

2. and sending a coordinator request network access instruction to the gateway.

3. After receiving the network access command (including the distributed coordinator address, the original Node number S _ Node and the use channel) of the approved coordinator replied by the gateway, recording the coordinator address, the original Node number and the use channel. All nodes are marked as fault states.

Note 1: since the coordinator is attached to the gateway in the network structure and has a one-to-one relationship, the allocated coordinator address and the gateway address are set.

Note 2: the gateway only transmits the original node number, but not the specific node address because the node address (2 bytes) is composed of the coordinator address (1 byte) and the network access serial number (1 byte), and the coordinator can automatically generate the original node address according to the original node number.

4. A coordinator channel selection instruction (including a coordinator address and an optional channel) is broadcast on channel 0.

5. Switch to channel 0 reception state, Wait for replies with a Wait time T _ Wait, whether a coordinator channel occupying command (including coordinator address and used channel) is received from another coordinator? If yes, judging that the channel is occupied, entering step 6, otherwise, judging that the channel is available, and entering step 9.

6. Is the coordinator selects a channel for command transmission equal to the total number of channels minus 1? If so, judging that the channel selection fails, and entering a step 7, otherwise, entering a step 8.

7. And (4) sending a coordinator channel selection failure instruction to the gateway, clearing the number of times of sending the coordinator channel selection instruction after waiting for a period of time (modifying according to needs), and returning to the step 4.

8. And changing the selected channel in the coordinator selection channel command and returning to the step 4.

9. And determining to send a coordinator Channel selection success instruction (containing a coordinator address and a use Channel) to the gateway by using the Channel _ Used.

10. And after receiving a gateway reply network establishment success instruction (including a time interval T _ Collect from the next data acquisition), updating the timer timing time T _ Collect and timing by the timer.

11. And switching to a channel 0 receiving state and monitoring the broadcast.

12. Is the timer timed to reach? If not, the listening broadcast phase is entered (steps 13-27), otherwise the data aggregation phase is entered (steps 28-39).

Listening broadcast phase (steps 13-27):

13. is an instruction received from a node or other coordinator? If so, go to step 14, otherwise return to step 12.

14. And reading the instruction and judging the type of the instruction. If it is a coordinator channel selection command (including the coordinator address and the selected channel), the process proceeds to step 15. If it is a node request network entry command (containing the node address), go to step 19.

Process other coordinator channel selection instruction subflow:

15. is the selected channel and the self-used channel in the coordinator channel selection instruction the same? If yes, the channel collision is judged and the step 16 is entered. Otherwise step 17 is entered.

16. And replying a coordinator channel occupying instruction (comprising a coordinator address and a used channel) in the channel 0.

17. Is there a node address first byte (i.e., coordinator address) in the own hosting node together with the address of the coordinator that sent the coordinator channel selection instruction? If there are such nodes, go to step 18, otherwise return to step 11.

18. And marking the managed node as a fault state, sending a node fault instruction (containing a node address) to the gateway, and returning to the step 11.

Note: after the managed node is marked to be in a fault state, the managed node is not inquired next time of data acquisition, the managed node judges the fault state of the managed node, starts a network re-accessing process and preferentially joins a network established by the original coordinator. Therefore, the function that the managed node returns to the network established by the original coordinator after the original coordinator is on line again is realized.

19. read command, determine command type? If the new node requests a network-accessing command (containing the address and the sensor class of the node), step 20 is entered. If the original node requests a network access instruction (including the address and the sensor class of the node), step 23 is entered. If the original node requests a network access instruction (including the address and the sensor class of the node), the step 21 is entered. If the node to be hosted requests a network access instruction (including the address and the sensor class of the node), step 25 is entered.

20. And allocating a node address, and sending an instruction (containing the node address) for allowing the new node to enter the network to the node in the channel 0.

Note: the node address (2 bytes) is composed of a coordinator address (1 byte) and a network access sequence number N (1 byte). The network access serial number N is the original Node number S _ Node + 1.

21. And switching to a channel 0 receiving state, waiting for a reply, wherein the waiting time is T _ Wait, and if a node confirmation network access command (including a node address) is received, entering a step 22. Otherwise, return to step 11.

Note: the waiting time T _ Wait is determined according to the time required by the 433M radio module to answer a single time actually adopted.

22. And updating the Node number S _ Node +1, marking the Node as a normal state, and sending a new Node network access instruction (including the address of the Node and the sensor type) to the gateway. Returning to step 11.

23. And sending a network access permission instruction (containing a node address) of the original node to the node in the channel 0.

24. And marking the node as a normal state, and sending an original node network access instruction (including the address of the node and the sensor category) to the gateway. Returning to step 11.

25. And sending an instruction (containing a node address and a use channel) for allowing the node to be managed to access the network to the node in the channel 0.

26. And switching to a channel 0 receiving state, waiting for a reply with a waiting time of T _ Wait, and if receiving a network access confirmation instruction (including a node address) of the node to be hosted, entering step 27. Otherwise, return to step 11.

27. And recording the address of the hosting node, marking the node as a normal state, and sending a network access instruction (including the address of the node and the category of the sensor) of the node to be hosted to the gateway. Returning to step 11.

Note: compared with the new Node network access, when the hosting Node network access, the coordinator does not update the Node number S _ Node and does not allocate a new address, so that the hosting Node can store the original network structure information.

Data aggregation stage (steps 28-38):

28. and after the timer reaches the set time, sending a command for acquiring the time of the next data acquisition to the gateway.

29. And after receiving a data acquisition time instruction (including a time interval T _ Collect from the next data acquisition) replied by the gateway, updating the timer timing time T _ Collect and timing by the timer.

30. And reading the address and the state of the first node, and clearing the total number N _ Error of the fault nodes and the number N _ Error _ Add of the newly added fault nodes.

31. If the node status is normal, the process proceeds to step 32. Otherwise, step 36 is entered.

32. And sending a data acquisition instruction (comprising a node address, a next data acquisition time interval T _ Collect, a total number of failed nodes N _ Error and a number of newly-added failed nodes N _ Error _ Add) to the node on a Used Channel _ Used (a Used Channel determined in the network entry stage of the coordinator).

33. Switching to a receiving state using a Channel _ Used, waiting for a reply, wherein the waiting time is T _ Wait, and if a node sends a measurement data instruction (including a node address and measurement data), entering step 34. Otherwise, step 35 is entered.

34. The measurement data is recorded, a coordinator data transmission command (including the node address and the measurement data) is sent to the gateway, and the process proceeds to step 37 after waiting for a predetermined time.

35. And marking the node as a fault state, updating the total number of the fault nodes N _ Error to be N _ Error +1, adding the number of the newly-added fault nodes N _ Error _ Add to be N _ Error _ Add +1, and sending a node fault instruction (containing a node address) to the gateway. Step 37 is entered.

36. Updating the total number of the fault nodes N _ Error to be N _ Error + 1;

37. is the node the last node (including the managed node)? If yes, go to step 38, otherwise go to step 39;

38. sending a data acquisition completion instruction of the current round to the gateway, and returning to the step 11;

39. the address and status of the next node are read and the process returns to step 31.

Claims

1. A self-networking and low-power consumption data collection method of a tree-type sensor network is characterized in that a sensor node is in wireless communication with a coordinator, the coordinator is in serial port communication with a relay gateway, the sensor node is responsible for measuring various environmental data on site and sending the data to the coordinator in a wireless mode, and the coordinator is in communication with the sensor node in a wireless mode, is responsible for establishing the sensor network and collecting the data measured by the sensor node; on the other hand, the relay gateway is communicated with the serial port and is responsible for forwarding the measurement data of the sensor node to the relay gateway and receiving the instruction of the relay gateway; the relay gateway has the function that after the measured data of each node are collected in the relay gateway, the data are fused by the gateway, and finally the data are sent to the monitoring server host through the wireless network;

1) initializing hardware configuration after the node is electrified;

a first network access stage:

4) broadcasting a new node request network access instruction in a channel 0;

and a network re-access stage:

13) randomly waiting for a period of time, and returning to the step 9);

data measurement and transmission stage:

20) assigning all the measurement data to 0;

24) recording a time interval T _ Collect for collecting data next time, a total number N _ Error of fault nodes and a number N _ Error _ Add of newly-added fault nodes, calculating the awakening timing time T _ Wake of a low-power-consumption processor next time, receiving the awakening time T _ Wait _ Collet of a wireless module, receiving the awakening time T _ Wait _ Collet of the wireless module, and timing the timer T _ Wake; t _ Measure is the sum of time required by the sensor on the node to Measure data and is determined by the type and the number of the sensors owned by the actual node;

26) closing all unused resources and entering dormancy;

28) marking the self fault state and returning to the step 8);

the method comprises the following specific steps:

the coordinator enters a network stage:

(1) initializing hardware configuration after the coordinator is powered on;

(2) sending a coordinator request network access instruction to a gateway;

(4) broadcasting a coordinator channel selection instruction on a channel 0;

(11) switching to a channel 0 receiving state, and monitoring broadcast;

and a broadcast monitoring stage:

process other coordinator channel selection instruction subflow:

(16) replying a coordinator channel occupation instruction in a channel 0;

(21) switching to a channel 0 receiving state, waiting for reply, wherein the waiting time is T _ Wait, if a node confirmation network access instruction is received, entering a step (22), and if not, returning to the step (11);

a data collection stage:

(32) sending a data acquisition instruction to a node on a Used Channel _ Used;