CN110769511A

CN110769511A - Reliable low-power-consumption high-throughput wireless sensor network data collection method

Info

Publication number: CN110769511A
Application number: CN201911042702.5A
Authority: CN
Inventors: 刘进志; 孙绍华; 张典
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2020-02-07

Abstract

The invention relates to a reliable low-power-consumption high-throughput wireless sensor network data collection method, and belongs to the technical field of wireless. The invention comprises the following steps: and (3) time slot allocation: each node allocates corresponding multi-channel sending time slots by utilizing a heuristic algorithm according to the topological structure of the network, the channels are allocated based on hop counts, and the heuristic algorithm is used for optimizing the time slot allocation; global synchronous multichannel receiving and transmitting: realizing global time synchronization based on constructive interference, and organizing multi-channel communication from each source node to a sink node and constructive flooding from the sink node to the source node by adopting a superframe structure based on time slot allocation; and (3) retransmission of the data packet: high throughput data transmission is realized by using an optimized multi-channel time slot allocation strategy, efficient scheduling of wireless communication opening and closing is realized on the basis of TDMA time slot allocation, and reliability is realized by using node-to-node data packet retransmission. The invention can realize reliability, low power consumption and high throughput.

Description

Reliable low-power-consumption high-throughput wireless sensor network data collection method

Technical Field

The invention relates to a reliable low-power-consumption high-throughput wireless sensor network data collection method, and belongs to the technical field of wireless.

Background

Wireless sensors are networked nodes distributed in space. The nodes cooperatively monitor conditions (e.g., temperature, sound, vibration, pressure, etc.) at various locations using wireless communication and sensor technologies. The wireless sensor nodes comprise a source node (source node) and a sink node (sink node). The nodes which are commercialized at present are Mica, Telos, Imote and other series.

Due to the characteristics of self-organization, microstructural property, low cost, flexibility, high monitoring precision, reliability, easiness in installation and the like, the wireless sensor network is applied to multiple fields. From smart grid, intelligent house, intelligent medical treatment, intelligent agriculture, wisdom bridge to structure detection, water quality testing, ocean detection, forest detection, factory detection etc. all need a ripe, stable, function complete and powerful data collection agreement.

Due to the constraints of the tree topology of the wireless sensor network, many-to-one traffic model, multi-hop communication mode, half-duplex wireless transceiver and other factors, the communication scheduling from a plurality of source nodes to tandem nodes is complex for high throughput applications. How to optimize the communication schedule of the uplink is a troublesome problem. Wireless communication is based on CSMA or TDMA. CSMA-based data collection protocols have flexibility but are inefficient and difficult to improve throughput. TDMA-based data collection protocols, while efficient, require optimized time slot scheduling algorithms to synchronize with stable time.

In addition, to achieve reliable data collection, the sink node needs to further inform the source node of information of packet retransmission, and therefore, communication from the sink node to the source node, i.e., downlink, is indispensable. The downlink problem has been a troublesome problem. This is mainly due to the fact that the communication from the source node to the sink node, i.e. the uplink, is in a many-to-one mode. Two-way communication in the uplink and downlink may cause collisions.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a reliable low-power-consumption high-throughput wireless sensor network data collection method.

The invention discloses a reliable low-power-consumption high-throughput wireless sensor network data collection method, which comprises the following steps:

s1: and (3) time slot allocation: each node allocates corresponding multi-channel sending time slots by utilizing a heuristic algorithm according to the topological structure of the network, the channels are allocated based on hop counts, and the heuristic algorithm is used for optimizing the time slot allocation and comprises the following steps:

s11: collecting a network topology structure based on a tree form by a sink node;

s12: each node represents whether a data packet needing to be sent exists or not by using a set 0 and a set 1;

all nodes except the sink node are set to be 1 in initial state, and the sink node is set to be zero forever;

s13: the algorithm loops as follows:

s131: traversing each node including the sink node, searching all the nodes which are set to be zero, and recording;

s132: when the cycle is finished, checking whether a node with a set 1 exists in the child nodes of the nodes with the set zero;

s133: if so, the sub-tree with the most 1-set nodes in the sub-tree of the zero-set node (note, A) is selected, the parent node (note, B) of the sub-tree is set to 0, the parent node (namely, the parent node A of B) is set to 1, and if the A node is the sink node, the zero-set is kept.

S134: the cycle is a TDMA multi-channel time slot, which is the sending time slot of the node B and the receiving time slot of the node A;

s14: time slot plus 1:

if all nodes in the network are in the zero setting 0 state, ending the time slot distribution, otherwise returning to the step of S13;

s2: global synchronous multichannel receiving and transmitting: realizing global time synchronization based on constructive interference, and organizing multi-channel communication from each source node to a sink node and constructive flooding from the sink node to the source node by adopting a superframe structure based on time slot allocation;

s3: and (3) retransmission of the data packet: the method realizes high throughput data transmission by using an optimized multi-channel time slot allocation strategy, realizes efficient scheduling of wireless communication opening and closing on the basis of TDMA time slot allocation, and realizes reliability by using node-to-node data packet retransmission, and comprises the following steps:

s31: one bit is used in the synchronization message to represent whether a data packet is successfully received;

set 0 means received and set 1 means not received.

S32: after receiving the synchronization message, the source node reads the corresponding bit information and retransmits the data packet which fails to be transmitted in the next frame data transmission.

Preferably, in step S1, the timeslot assignment operation must be combined with multi-channel communication, and the channel selected by the node is assigned based on the hop count, and is switched to the destination node channel when transmitting and switched back to its own node when receiving.

Preferably, in step S1, after the time slot allocation is performed by the heuristic algorithm, the time slots for receiving and sending the data packet of each node are further calculated by combining the topology structure, so as to implement efficient scheduling of wireless communication on and off, thereby implementing low power consumption.

Preferably, in step S2, a superframe of the superframe structure is composed of multiple channel slots from each source node to the sink node and common channel slots from the sink node to the source node.

Preferably, in step S2, in the multi-channel time slot, the source node sends the packet and collects forwarding completion data to the parent node.

Preferably, in the step S2, in the common channel timeslot, the sink node floods the synchronization message to the source node by using constructive interference, so as to implement global time synchronization.

Preferably, in step S3, the data packet retransmission is implemented based on NACK; and carrying packet loss information of corresponding nodes in each superframe in the synchronization message, realizing downlink communication from the source node to the sink node, and finally realizing data packet retransmission from the node to the node.

Preferably, in step S3, the data packet retransmission uses the payload space of the synchronization message, and uses a one-bit binary number to represent whether a data packet is successfully received;

setting 0 represents receiving, and setting 1 represents not receiving; and after receiving the synchronization message, the source node extracts NACK information and retransmits the lost data packet in the next superframe.

It should be noted that: the time slots other than the transmit and receive time slots turn off wireless communication.

The invention has the beneficial effects that:

(1) the communication is realized based on TDMA, and the network time synchronization required by the TDMA is realized based on constructive interference;

(2) the invention realizes the time slot distribution from the source node to the sink node by using a heuristic algorithm, and the time slot distribution can be optimized;

(3) the invention realizes the data packet flooding from the source node to the sink node by utilizing constructive interference; realizing time distribution of bidirectional communication between the source node and the sink node by utilizing a superframe structure;

(4) the invention realizes the reliability of data transmission based on the NACK data packet retransmission. The NACK information is carried in a flooding synchronization message realized by constructive interference;

(5) the invention can make the time for starting the wireless communication to be the minimum by accurately calculating the sending and receiving time slots, thereby realizing low power consumption.

Drawings

Fig. 1 is a source node work flow diagram of the present invention.

FIG. 2 is a flow chart of the operation of the sink node of the present invention.

Fig. 3 is a hop count based channel allocation diagram of the present invention.

Fig. 4 is a constructive interference working schematic diagram of the present invention.

Fig. 5 is a diagram of a superframe data collection operation cycle of the present invention.

Fig. 6(a) is a diagram of multi-channel data collection according to the present invention.

Fig. 6(b) is a diagram of multi-channel data collection according to the present invention.

Fig. 7 is a diagram of a multi-channel packet structure of the present invention.

Fig. 8 is a MAC layer load diagram of the present invention.

Fig. 9 is a diagram of a common channel packet structure of the present invention.

Fig. 10 is a design diagram of NACK of the present invention.

FIG. 11(a) is a Node ID map.

Fig. 11(b) is an initial data map.

Fig. 11(c) is a Slot 1 diagram.

Fig. 11(d) is a Slot 2 diagram.

Fig. 11(e) is a Slot 3 diagram.

Fig. 11(f) is a Slot4 diagram.

Fig. 11(g) is a Slot5 diagram.

Fig. 11(h) is a Slot 6 diagram.

Fig. 11(i) is a Slot4 packet loss map.

Fig. 11(j) is a Slot5 diagram after packet loss.

Fig. 11(k) is a second flooding graph.

FIG. 11(l) is a data diagram of the buffer after the second flooding.

Fig. 12 is a TelosB node diagram.

Detailed Description

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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.

Example 1:

as shown in fig. 1 and fig. 2, the reliable data collection method for a low-power-consumption high-throughput wireless sensor network according to the present invention includes the following steps:

s13: the algorithm loops as follows:

s14: time slot plus 1:

as shown in fig. 3 to 12, S2: global synchronous multichannel receiving and transmitting: realizing global time synchronization based on constructive interference, and organizing multi-channel communication from each source node to a sink node and constructive flooding from the sink node to the source node by adopting a superframe structure based on time slot allocation;

set 0 means received and set 1 means not received.

In step S1, the time slot allocation must be performed in conjunction with multi-channel communication, and the channel selected by the node is allocated based on the hop count, and is switched to the destination node channel during transmission and switched back to its own node during reception.

In step S1, after the time slot allocation is performed by the heuristic algorithm, the data packet receiving and sending time slots of each node are further calculated in combination with the topology, so as to implement efficient scheduling of wireless communication on and off, thereby implementing low power consumption.

In step S2, a superframe of the superframe structure is composed of multiple channel slots from each source node to the sink node and common channel slots from the sink node to the source node.

In step S2, in the multi-channel time slot, the source node sends the packet to the parent node and collects the forwarding completion data.

In step S2, in the common channel timeslot, the sink node floods the synchronization message to the source node by using constructive interference, so as to implement global time synchronization.

In step S3, the packet retransmission is performed based on NACK; and carrying packet loss information of corresponding nodes in each superframe in the synchronization message, realizing downlink communication from the source node to the sink node, and finally realizing data packet retransmission from the node to the node.

Example 2:

in view of the existing problems, the invention provides a wireless sensor network data collection method capable of realizing reliability, low power consumption and high throughput, which comprises three parts.

S1: and (3) time slot allocation: each node allocates corresponding multi-channel sending time slots by utilizing a heuristic algorithm according to the topological structure of the network, and the algorithm comprises the following specific steps:

(1) collecting a network topology structure based on a tree form by a sink node;

(2) each node uses 0 and 1 to represent whether there is a data packet to be sent. All nodes except the sink node are set to be 1 in initial state, and the sink node is set to be zero forever;

(3) the algorithm loops as follows: and traversing each node (including the aggregation node), searching all the nodes which are set to be zero, and recording. When the loop is finished, checking whether the sub-nodes of the nodes to be set to zero have the nodes to be set to 1. If so, the sub-tree with the most 1-set nodes in the sub-tree of the zero-set node (note, A) is selected, the parent node (note, B) of the sub-tree is set to 0, the parent node (namely, the parent node A of B) is set to 1, and if the A node is the sink node, the zero-set is kept. The cycle is a TDMA multi-channel time slot, which is the sending time slot of the node B and the receiving time slot of the node A;

(4) the time slot is incremented by 1. If all nodes in the network are in the zero 0 state, ending the time slot allocation, otherwise, returning to the step (3) for execution.

The heuristic algorithm optimizes the time slot allocation, thereby achieving high throughput. Its operation must combine multi-channel communication, the channel selected by node is distributed based on hop number, when transmitting, it is switched to the destination node channel, when receiving, it is switched back to its own node. After the heuristic algorithm is used for time slot allocation, the data packet receiving and sending time slots of all the nodes are further calculated by combining the topological structure, and efficient scheduling of wireless communication opening and closing is realized, so that low power consumption is realized.

S2: global synchronization, multichannel data transceiving: the TDMA communication needs global time synchronization, and the invention realizes the global time synchronization based on constructive interference. Constructive interference as shown in fig. 4, if both receiver 1 and receiver 2 are within communication range of the initiator, they simultaneously forward the initiator's packet using constructive interference after receiving the packet. Based on global time synchronization and time slot allocation, a superframe structure is adopted to organize multichannel communication from each source node to a sink node and constructive flooding from the sink node to the source node, namely the superframe is composed of multichannel time slots from each source node to the sink node and common channel time slots from the sink node to the source node. As shown in fig. 5, one constructive interference is followed by multiple channel data collection periods. And in the multi-channel time slot, the source node sends the data packet to the father node and completes the collection of the data after forwarding. As shown in fig. 6, for example, if the node 1 is a sink node and the

nodes

2, 3, 4, 5, and 6 are source nodes, a data collection cycle is shown after allocating time slots according to the heuristic algorithm. The packet design for multi-channel data transceiving is shown in fig. 7. The microcontroller can maximally operate 127 bytes of data space. As shown in fig. 8, the MAC layer provides a maximum of 121 bytes for piggybacking data information. In the time slot of the public channel, the sink node floods the synchronous message to the source node by utilizing constructive interference to realize global time synchronization.

S3: and (3) retransmission of the data packet: reliability is achieved with point-to-point data packet retransmission. That is, the sink node informs the packet loss information of each sink node, and then the sink node sends the data packet again. The data packet retransmission is implemented on the basis of NACK. I.e. the source node only sends the missing packet number. The sink node needs to inform the source node of the lost data packet, and therefore, the synchronization message carries packet loss information of corresponding nodes in each superframe, downlink communication from the source node to the sink node is achieved, and finally point-to-point data packet retransmission is achieved. To fully utilize the payload space of the synchronization message, a one-bit binary number is used to indicate whether a data packet was successfully received. Set 0 means received and set 1 means not received. The source node extracts NACK information after receiving the synchronization message, and retransmits the lost data packet in the next superframe, which is specifically designed as shown in fig. 9. The data content is the packet loss information carried by the sink node. Unlike multi-channel packets, the length of the common channel packets is not suitable for being too long, because too long packets tend to cause constructive interference failure. The length is also selected in relation to the number of nodes in the overall network, the length of the superframe, etc. The specific use of the data content portion in fig. 9 is shown in the fig. 10 design. The implicit method is used to carry the packet loss information. For example, if each superframe contains 5 data periods, packet loss of one node per 5 bits is sequenced according to the node ID.

The above three parts form the invention as a whole.

Example 3:

the technical solution of the present invention will be further described in detail with reference to the accompanying drawings and embodiments.

The invention uses a half-duplex transmission protocol of flooding type rapid collection, which comprises a collection Node (SinkNode) and Source nodes (Source nodes) of all sensors, and realizes rapid collection and reliable communication of Source Node data by using radio flooding.

Aiming at the collection Node Sink Node, data from each Node is continuously received without considering any power consumption, collected and transmitted to an upper computer.

And aiming at the Source Node, sending and receiving data according to the receiving and sending sequence obtained by the topological structure. Sending the data collected by the node (such as the data from each sensor) to the upstream node. After the first transmission, the data from the downstream node is received, but only the data is transmitted and forwarded, and the content of the data packet is not saved.

In this example, it is assumed that a Node topology is known and a topology structure is not changed in a communication process, as shown in fig. 11(a), a collection Node (Sink Node) and 5 Source nodes (Source nodes) are arranged in a tree structure. The node numbers are 1 to 6, respectively.

Step 101: and calculating the type of each Node in each time Slot according to the topological structure information, and calculating the Hop count of the Sink Node.

Step 102: the Sink Node is used as an initiator of the flooding process and initiates flooding signals to other nodes, and the initial flooding data is binary 00000. The flooding process is referred to as shown in fig. 11 (k).

Step 103: the Source Node receives the flooding data at the same time, and sends out the same flooding data immediately and simultaneously.

Step 104: the Sink Node receives the flooding data from each Source Node, and if the data content matches the content sent before, the flooding count is increased by 1.

Step 105: if the flooding count does not reach 10, the Sink Node initiates the same flooding signal to other nodes as before, and executes step 103; if the flooding count reaches 10 times and the flooding cycle count does not reach 5 times, then the flooding cycle count is incremented by 1, and the next cycle of flooding (assuming 2 seconds) is waited, go to step 102; if the flooding count reaches 10 times and the flooding cycle count reaches 5 times, entering a rapid collection procedure, and executing step 106;

step 106: the Source Node retransmits the original lost data packet according to the packet loss condition sent by the Sink Node and by combining the current data packet count, stores the data to be transmitted into a receiving and transmitting buffer zone, and waits for the arrival of the first slot time.

When this step is executed for the first time, it is assumed that the data in the initial transmission buffer of each Node is as shown in fig. 11(B), Node 1 is a Sink Node, there is no data, Node 2 is a, Node 3 is B … …, and so on

Step 107: the first Slot, as shown in fig. 11(c), in which only node 2 transmits data a in the buffer to node 1, the remaining nodes are in a sleep state.

And (3) judging a rule: the Source Node judges the type of the current Slot, and if the type is a sending type, the data in the buffer area is sent; if the type is the receiving type, receiving data to a buffer area; if the type is the non-receiving and non-transmitting type, the power is saved by dormancy, and the next Slot is waited.

Step 108: a second Slot, as shown in fig. 11(d), in which the node 3 transmits the data B in the buffer to the node 2; the node 5 sends the data D in the buffer area to the node 1; the rest nodes are in a dormant state.

Step 109: a third Slot, as shown in fig. 11(e), in which node 2 sends data B in the buffer to node 1; the node 6 sends the data E in the buffer area to the node 5; the rest nodes are in a dormant state.

Step 110: a fourth Slot, as shown in fig. 11(f), in which the node 4 transmits the data C in the buffer to the node 2; the node 5 sends the data E in the buffer area to the node 1; the rest nodes are in a dormant state.

Step 111: a fifth Slot, as shown in fig. 11(g), in which node 2 transmits data C in the buffer to node 1; the rest nodes are in a dormant state.

Step 112: the sixth Slot, as shown in fig. 11(h), is where node 1 performs statistics and processing on all received data.

Step 113: if the data collection period is not full for n times, the Slot starts to calculate from 1 again next time, the Source Node acquires data from the sensor and the like again and writes the data into the data buffer area, and then the next data collection period is prepared to enter. Waiting for the Slot of the next period to arrive, and executing the step 107 again; if the data collection cycle is n times full, go to step 114.

In the illustrated example, let n be 1, i.e. only 1 collection per flood. Of course, the time interval of flooding and the number of data collection between each flooding can be adjusted according to actual conditions.

Step 114: and the Sink Node counts the packet loss conditions of all the data packets, writes the packet loss conditions of all the nodes into the flooding data packets, and waits for the next flooding time trigger.

If all the packets are received, the data in the flooding packet is binary 11111. I.e. 1 for received and 0 for not received.

If packet loss occurs: if, as shown in fig. 11(i), packet loss occurs at Slot4 when node 4 and node 5 transmit C and E. Slot5, node 2 would send a null packet to node 1 as shown in fig. 11 (j). Then, the data packet finally collected by the node 1 is only ADB, and then the data packet is marked according to the node number sequence arrangement, so that the data in the finally flooded data packet is binary 11010, and for this situation, the buffer data ready to be sent after flooding in the next round are FGCIE respectively, as shown in fig. 11(l), that is, the

nodes

2, 3, 5 will send new data: FGI, and nodes 4, 6 will be ready to send the data of the previous cycle again due to the packet loss flag of the flooding data, i.e. C and E, thereby realizing reliable transmission.

Step 115: the Sink Node is used as an initiator of the flooding process, initiates flooding signals to other nodes, and executes step 103.

Example 4:

and (3) experimental verification:

based on the topology, the invention is realized on a TelosB node platform. The TelosB node used is shown in fig. 12. Experiments were performed under three scenarios: (1) the ideal place is as follows: inside the elevator, the closed environment of elevator is from taking the shielding signal function, and the channel space is comparatively ideal. This set of experimental data was used as a benchmark for reference. (2) Indoor: WiFi interference is serious, and the method is suitable for application scenes of smart homes. (3) Outdoor: the 2.4GHz interference is less, and the method is suitable for the application scene of environment monitoring.

Table 1: where wireless signals are more desirable

Table 2: indoor location

Table 3: outdoor occasion

As shown in tables 1, 2, and 3, the data statistics (1) data collection protocol implemented by the present invention can provide a throughput of up to 16.13Kbyte/S, which is not achieved by existing work. (2) On the premise of high throughput, the wireless communication energy can be considered to be controlled to the maximum capacity, so that low power consumption is realized. (3) The wireless link quality difference is obvious in different occasions, the packet loss rates are different, and 100% of data can be reliably collected through all the wireless link quality differences.

The present invention also has many embodiments, and those skilled in the art can make various changes and modifications according to the present invention without departing from the spirit and the essence of the invention, and these changes and modifications should fall into the protection scope of the appended claims.

The invention can be widely applied to wireless technical occasions.

It is well within the skill of those in the art to which circuits and electronic components and modules relate, without undue experimentation, that the protection sought herein does not involve software and process modifications.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A reliable data collection method for a wireless sensor network with low power consumption and high throughput is characterized by comprising the following steps:

s13: the algorithm loops as follows:

s133: if yes, selecting the sub-tree with the most 1-set nodes in the subtree of the type of the nodes (note, A) to be set to zero, setting the parent node (note, B) of the subtree to 0, setting the parent node A of B to 1, and if the node A is a sink node, keeping the setting to zero;

s14: time slot plus 1:

setting 0 represents receiving, and setting 1 represents not receiving;

2. The method of claim 1, wherein the time slot assignment must be performed in conjunction with multi-channel communication in step S1, the channel selected by the node is assigned based on hop count, and the channel is switched to the destination node when transmitting and switched back to its own node when receiving.

3. The reliable low-power-consumption high-throughput wireless sensor network data collection method according to claim 1, wherein in step S1, after time slot allocation is performed by a heuristic algorithm, data packet receiving and sending time slots of each node are further calculated by combining a topology structure, so as to implement efficient scheduling of wireless communication on and off, thereby implementing low power consumption.

4. The reliable low-power high-throughput wireless sensor network data collection method according to claim 1, wherein in step S2, one superframe of superframe structure organization is composed of multiple channel slots from each source node to sink nodes and common channel slots from sink nodes to source nodes.

5. The reliable low-power-consumption high-throughput data collection method for wireless sensor networks according to claim 1, wherein in step S2, the source node transmits and forwards data packets to the parent node in a multi-channel time slot to complete data collection.

6. The reliable low-power-consumption high-throughput data collection method for wireless sensor networks according to claim 1, wherein in step S2, the sink node floods the synchronization message to the source node by using constructive interference during the common channel time slot, so as to achieve global time synchronization.

7. The reliable low-power high-throughput wireless sensor network data collection method according to claim 1, wherein in step S3, data packet retransmission is implemented based on NACK; and carrying packet loss information of corresponding nodes in each superframe in the synchronization message, realizing downlink communication from the source node to the sink node, and finally realizing data packet retransmission from the node to the node.

8. The reliable, low-power, high-throughput wireless sensor network data collection method according to claim 7, wherein in step S3, the data packet retransmission uses the payload space of the synchronization message and uses a one-bit binary number to represent whether a data packet is successfully received;