CN106922008B - IPv6 wireless sensor network multi-path transmission method based on RPL routing protocol - Google Patents

Abstract

The invention relates to an IPv6 wireless sensor network multi-path transmission method based on an RPL routing protocol, and belongs to the technical field of wireless sensor networks. In the 6LoWPAN wireless sensing network based on the IPv6 technology, a parent node set generated during routing is constructed by utilizing an RPL (resilient packet link) protocol according to hop values from source nodes to sink nodes and node residual energy, and a message is copied to multiple copies and then distributed to multiple RPL parent nodes for forwarding according to the reliability requirement of the message and the Rank value of the parent node. In order to enable the 6LoWPAN network to support multi-path message transmission, the method designs a new 6LoWPAN header-multi-path header at an adaptation layer, and the new 6LoWPAN header is used for copying the message to multiple paths for transmission and finally eliminating the message. The invention can improve the reliability of message transmission in the network by increasing the redundant path during message transmission, and can effectively prolong the network lifetime by considering the node residual energy and the hop count to the sink node during selecting the transmission path.

Description

A Multipath Transmission Method for IPv6 Wireless Sensor Network Based on RPL Routing Protocol

technical field

The invention belongs to the technical field of wireless sensor networks, and relates to an IPv6 wireless sensor network multi-path transmission method based on the RPL routing protocol.

Background technique

Wireless sensor network has always been regarded as the current international research hotspot, and it is one of the core research contents of Internet of Things technology. aspect.

The introduction of IPv6 technology into wireless sensor network enables each sensor node to have a unique IPv6 address, realizes the IP communication between the node and the host, and successfully extends the application on the Internet to the wireless sensor network. In addition, the 6LoWPAN network that combines wireless sensor network and IPv6 technology has high popularity and applicability, and more address space meets the needs of deploying large-scale, high-density and low-speed wireless personal area network equipment. However, due to the defects of low processing capability, limited energy and poor communication environment of sensor nodes in 6LoWPAN network, packet loss is prone to occur in packet transmission, resulting in transmission failure. In order to increase the reliability of message communication and improve the performance of message transmission, it is particularly important to introduce a multi-path message transmission technology into the 6LoWPAN network.

At present, a variety of multi-path routing technologies have been proposed in the field of wireless sensor networks. Although multiple transmission paths can be established for packet transmission, they cannot be directly improved and applied to 6LoWPAN networks. In order to propose a multi-path transmission method suitable for 6LoWPAN network, the existing routing protocol is used to realize it. As a routing protocol standardized by IETF, RPL is widely used in 6LoWPAN networks. The RPL routing protocol has designed a series of new mechanisms. It is an efficient distance vector protocol for wireless sensor networks. Nodes construct a directed acyclic graph by exchanging distance vectors, which can be used to avoid multi-path forming loops. However, only one transmission path is used in the packet transmission process, which is prone to failure of packet transmission, which reduces the transmission reliability of the network.

In order to ensure the reliability of the message transmission in the wireless sensor network, in view of the possible failure of the message transmission in the 6LoWPAN network, based on the RPL routing protocol, the present invention proposes an IPv6 wireless sensor network multipath based on the RPL routing protocol. The transmission method aims to improve the reliability of 6LoWPAN network packet transmission.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a kind of IPv6 wireless sensor network multi-path transmission method based on RPL routing protocol, the method utilizes RPL protocol according to the hop value of node to the convergence node and the residual energy of the node generated when the route is constructed. A set of nodes that establishes multiple message transmission paths to multiple parent nodes. The method can solve the problem of message transmission failure, effectively improve the end-to-end transmission success rate of the message, and improve the transmission reliability of the network.

To achieve the above object, the present invention provides the following technical solutions:

A multi-path transmission method for IPv6 wireless sensor network based on RPL routing protocol. In this method, when the source node sends a message, it first determines the number of paths required to transmit the message, and then uses the size relationship between the Rank values. The number of paths corresponding to the Rank value is allocated to each parent node. The Rank value is calculated by the RPL according to the remaining energy value of the node and the hop value to the sink node, and the number of paths is encapsulated in the multipath of the packet at the adaptation layer. In the header, it is sent to the parent node corresponding to the Rank, and each intermediate routing node forwards the message according to the above method until it is sent to the sink node.

Further, the method specifically includes the following steps:

S1: After receiving the message from the upper layer of the protocol stack, the multipath transmission entity of the adaptation layer determines the total number of paths P required to transmit the message according to the reliability requirements of the message; when P is less than or equal to 1, Indicates that the message does not need to use multi-path transmission, then the message is directly forwarded;

S2: when the total number of paths P required to transmit the message is greater than 1, use the multi-path message allocation method to allocate the number of copies C that need to forward the message to each parent node in the RPL parent node set;

S3: For the parent node whose forwarding number C is greater than or equal to 1, the multipath transmission entity copies the message and adds the multipath header to the header of its adaptation layer, and then sends the message to the parent node; the multipath transmission entity sends the message to the parent node; The path header includes the header type description field, the multipath packet sequence number field (SequenceNumber), and the path count field (PathCount); among them, the multipath packet sequence number field of the multipath header in all replicated packets must be consistent, and When the next new message is sent, it is accumulated, and the path number field is filled with the corresponding forwarding number C; for the parent node whose forwarding number C is less than 1, the duplicated message is not sent;

S4: After receiving the packet containing the multipath header, the intermediate routing node judges whether the value of PathCount in the path number field in the multipath header is equal to 1. If PathCount is equal to 1, the value of each field in the multipath header remains unchanged. Directly forward the message; if PathCount is greater than 1, the message needs to continue to copy PathCount at this node and distribute it to multiple paths, repeat steps S2 and S3, in step S2 P is equal to PathCount, in step S3, do not Re-add a new multi-path header and keep the serial number field of the multi-path packet unchanged, and change the path number field to fill the corresponding forwarding number C;

S5: When the destination node receives the packet containing the multipath header, it can determine whether the packet has been received before through the multipath packet sequence number field and source address in the multipath header, and if not, it will be passed to the upper layer protocol, if any, discard the packet.

Further, in step S2, the described multi-path message distribution method is: if the number of paths P required by the sending node is greater than the total number of parent nodes in the RPL parent node set, then according to the size between the Rank values of each parent node. The relationship assigns multiple paths to each parent node, using the following formula:

Among them, round() is the rounding function, which is used for rounding the subsequent calculation results; P is the total number of paths, P _m is the number of paths allocated to the parent node m; R _m is the Rank value corresponding to the parent node m ( m=1, 2, ..., n).

If the number of paths P is less than or equal to the number of parent nodes, then select P Rank values in order from small to large, and assign a path to the parent node corresponding to each Rank value.

Further, in step S3, the multipath header includes a header type description field, a multipath packet sequence number field (SequenceNumber) and a path number field (PathCount); wherein, the message headers of different types of the adaptation layer must be in front of the header. There is a header type description field with a length of 8 bits; the SequenceNumber field contains the unique sequence number of the message, with a length of 16 bits; the PathCount field contains the number of paths that the node needs to fill to send or forward the message, with a length of 8 bits.

The beneficial effects of the present invention are:

1) The method can effectively improve the end-to-end transmission success rate of packets in the IPv6 wireless sensor network, and improve the transmission reliability of the network. Multi-path packets with high reliability requirements are sent to corresponding multiple parent nodes by pre-allocating the number of paths, so as to establish multiple transmission paths, thus effectively solving the problem of easy failure of single-path packet transmission in 6LoWPAN networks The problem.

2) The method can effectively balance energy consumption and relieve network congestion. When the sending node allocates the number of packets that need to be forwarded, that is, the number of paths, through the Rank value of the parent node, the calculation of the Rank value of the parent node needs to consider two parameters, the hop value from the node to the sink node and the remaining energy value. The consideration of energy is conducive to energy balance and avoids too many packets being forwarded by intermediate routing nodes with lower energy.

Description of drawings

In order to make the purpose, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings for description:

Fig. 1 is the flow chart of the 6LoWPAN network multi-path transmission method according to the present invention;

Fig. 2 is the 6LoWPAN protocol stack architecture diagram of the present invention;

Fig. 3 is the multi-path header frame format diagram of the adaptation layer according to the present invention;

4 is a schematic diagram of a single parent node message transmission according to the present invention;

5 is a schematic diagram of message transmission of multiple parent nodes (the number of paths P is greater than the number of parent nodes) according to the present invention;

FIG. 6 is a schematic diagram of packet transmission of multiple parent nodes (the number of paths P is less than or equal to the number of parent nodes) according to the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1 is a flow chart of the multi-path transmission method in the 6LoWPAN network. In the 6LoWPAN network, when the source node sends a message, it first determines the number of paths required to transmit the message, and then assigns one or more paths to each parent node through the Rank value. Path, Rank value is calculated by its parent node according to its own residual energy value and hop value to the sink node, and the number of paths is encapsulated in the multi-path header of the packet at the adaptation layer, and sent to the corresponding Rank value. The parent node, each intermediate routing node forwards the message according to the above method until it is sent to the sink node.

The method specifically includes the following steps:

S1. After receiving the message from the upper layer of the protocol stack, the multipath transmission entity of the adaptation layer determines the total number of paths P required to transmit the message according to the reliability requirements of the message. When P is less than or equal to 1, it indicates that the packet does not need to use multi-path transmission, and the packet is forwarded directly;

S2. When the total number of paths P required to transmit the message is greater than 1, use the multi-path message allocation method to allocate the number of copies C that need to forward the message to each parent node in the RPL parent node set;

S3. For the parent node whose forwarding number C is greater than or equal to 1, the multipath transmission entity copies the message and adds the multipath header to its adaptation layer header, and then sends the message to the parent node, and the multipath header This part contains the header type description field, the multipath packet sequence number field (SequenceNumber) and the path number field (PathCount). Among them, the multi-path packet sequence number field in the multi-path header of all duplicated packets must be consistent, and is accumulated when sending the next new packet, and the path number field is filled with the corresponding forwarding copy number C. For the parent node whose forwarding number C is less than 1, the duplicated message will not be sent;

S4. After receiving the packet containing the multipath header, the intermediate routing node determines whether the value of the path number field in the multipath header is equal to 1. If PathCount is equal to 1, the value of each field in the multipath header remains unchanged. Directly forward the packet; if PathCount is greater than 1, the packet needs to continue to copy PathCount at this node and distribute it to multiple paths, repeat steps 102 and 103, in step 102 P is equal to PathCount, in step 103, do not Re-add a new multi-path header and keep the serial number field of the multi-path packet unchanged, and change the path number field to fill the corresponding forwarding number C;

S5. When the destination node receives the packet containing the multipath header, it can determine whether the packet has been received before through the multipath packet sequence number field and source address in the multipath header, and if not, it is passed to the upper layer protocol, if any, discard the packet.

FIG. 2 shows the architecture diagram of the 6LoWPAN protocol stack. In the present invention, the multi-path message transmission is realized through the RPL routing and the multi-path header designed by the adaptation layer adopted by the network layer.

Figure 3 shows the frame format diagram of the multipath header of the adaptation layer. The multipath header designed by the adaptation layer includes the header type description field, the multipath packet sequence number field (SequenceNumber) and the path count field (PathCount). Among them, different types of message headers at the adaptation layer must be preceded by a header type description field with a length of 8 bits; the SequenceNumber field contains the unique sequence number of the message, defined as a length of 16 bits; the PathCount field contains the node sending or forwarding The number of paths required for the message, defined as 8 bits in length.

FIG. 4 shows a schematic diagram of packet transmission in the case where the source node has only one parent node. The following will take the figure as an example to describe the packet transmission process. As shown in the figure, the source node determines the required number of paths P=8 according to the reliability requirements. Since it has only one parent node, P=8 is directly assigned to PathCount, that is, PathCount=8, and then the multi-path header is encapsulated In the message, it is directly sent to the only parent node, and the parent node forwards the message after receiving the message.

FIG. 5 is a schematic diagram of message transmission in the case where the source node has multiple parent nodes (the number of paths P> the number of parent nodes), and the message transmission process will also be described below by taking the figure as an example. As shown in the figure, the source node determines the required number of paths P=8 according to the reliability requirements, and the source node has 3 parent nodes, then it is necessary to allocate path bars to the parent node according to the size relationship between the Rank values of the parent nodes number, using the following distribution formula:

得到以下计算结果：

The following calculation results are obtained:

Then, assign the values of P ₁ , P ₂ , and P ₃ to PathCount respectively, that is, PathCount ₁ =5, PathCount ₂ =1, and PathCount ₃ =2. After encapsulating the multi-path header in the message, send it to the corresponding The parent nodes A, B, and C obtain a new P value after receiving the message, that is, P=PathCount. Then, the same packet distribution method is adopted and the packets are forwarded. When the destination node receives the first packet containing the multipath header, it passes it to the upper-layer protocol, and the remaining 7 packets containing the same packet sequence number are discarded and not passed to the upper-layer protocol.

FIG. 6 shows a schematic diagram of message transmission in the case where the source node has multiple parent nodes (the number of paths P<=the number of parent nodes), and the message transmission process will also be described below by taking the figure as an example. As shown in the figure, the source node determines the required number of paths P=3 according to the reliability requirements, and the source node has 4 parent nodes, then the Rank value is selected in ascending order. Here, the Rank values are selected as 100 and 200 respectively. , 500 three paths, the subsequent packets will be sent to the sink node along one path respectively. Similarly, when the destination node receives the first packet containing the multipath header, it passes it to the upper-layer protocol, and the remaining two packets containing the same packet sequence number are discarded and not passed to the upper-layer.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should Various changes may be made in details without departing from the scope of the invention as defined by the claims.

Claims (1)

1. A IPv6 wireless sensor network multi-path transmission method based on RPL routing protocol is characterized in that: in the method, when a source node sends a message, the number of path strips required for transmitting the message is determined, then the number of the path strips corresponding to a Rank value is distributed to each father node through the size relation between the Rank values, the Rank value is obtained by calculation of an RPL (resilient packet layer) according to the node residual energy value and the hop value to a sink node, the number of the path strips is packaged in a multi-path header of the message in an adaptation layer and sent to the father node corresponding to the Rank, and each intermediate routing node forwards the message according to the method until the message is sent to the sink node; the method specifically comprises the following steps:

s1: after receiving a message transmitted from an upper layer of a protocol stack, an adaptation layer multi-path transmission entity determines the total path number P required by transmitting the message according to the reliability requirement of the message; when P is less than or equal to 1, the message is directly forwarded out if the message does not need to use multipath transmission;

s2: when the total number P of paths required for transmitting the message is more than 1, distributing the number C of copies of the message to be forwarded to each father node in the RPL father node set by using a multi-path message distribution method;

s3: for a father node with the forwarding number of copies C being more than or equal to 1, the multi-path transmission entity copies a message, adds a multi-path head in the head of an adaptation layer of the message, and then sends the message to the father node; the multi-path header includes a header type specification field, a multi-path packet sequence number field (sequence number), and a path number field (PathCount); the multipath packet sequence number fields of the multipath heads in all the copied messages are required to be consistent and accumulated when the next new message is sent, and the path number field is filled with the corresponding forwarding number C; the father node with the forwarding number of copies C less than 1 does not send the copied message;

s4: after receiving the message containing the multipath head, the intermediate routing node judges whether the value PathCount of the path number field in the multipath head is equal to 1, if the PathCount is equal to 1, the intermediate routing node keeps the value of each field of the multipath head unchanged and directly forwards the message; if PathCount is greater than 1, the message needs to continuously copy PathCount copies at the node and distribute the PathCount copies to multiple paths, step S2 and step S3 are repeated, P equals PathCount in step S2, in step S3, a new multipath header is not added again and a multipath packet sequence number field is kept unchanged, and it is only required to change the path number field to fill the corresponding forwarding copy number C;

s5: after receiving the message containing the multipath head, the destination node judges whether the message is received before through the multipath packet serial number field and the source address in the multipath head, if not, the message is transmitted to an upper layer protocol, and if so, the message is discarded;

in step S2, the multi-path packet allocation method includes: if the number P of paths required by the sending node is greater than the total number of father nodes in the RPL father node set, allocating a plurality of paths for each father node according to the size relationship between the Rank values of each father node, and adopting the following formula:

wherein, round () is a rounding function, and rounding processing is carried out on the following calculation result; p is the total number of paths, P _mIs the number of paths allocated to the parent node m; r _mIs the Rank value corresponding to the parent node m (m ═ 1, 2, …, n);

if the number P of paths is less than or equal to the number of father nodes, sequentially selecting P Rank values according to the order of the Rank values from small to large, and allocating a path to the father node corresponding to each Rank value;

in step S3, the multipath header includes a header type specification field, a multipath packet sequence number field (sequence number), and a path number field (PathCount); wherein, the front of different types of message headers of the adaptation layer must have a header type description field with the length of 8 bits; the sequence number field contains the unique serial number of the message, and the length is 16 bits; the PathCount field contains the number of paths to be filled for the node to send or forward the message, and the length is 8 bits.

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