CN111314977A

CN111314977A - Design method of IPv6 mobile sensing route

Info

Publication number: CN111314977A
Application number: CN202010092966.8A
Authority: CN
Inventors: 谢昊飞; 袁兴未; 贾哲健; 王志慧; 张量
Original assignee: Chongqing University of Post and Telecommunications
Current assignee: Chongqing University of Post and Telecommunications
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2020-06-19

Abstract

The invention relates to a design method of an IPv6 mobile sensing route, belonging to the technical field of wireless sensing. On the premise of being compatible with an original RPL routing protocol, the method adds an RSSI field with an average RSSI value in a DIO message and a DIS message, thereby providing a mobile sensing routing information interaction basis. The mobile-aware routing is divided into three stages of mobility detection and transmission, reaction and prediction and notification. In the mobility detection and transmission stage, the mobility of the node is detected by judging whether the received signal strength information is lower than a threshold value; the reaction and prediction phase predicts a new associated node by transceiving control messages using the new location of the mobile node; the notification phase completes the update of the route by sending a control message. The invention enables the IPv6 wireless sensor network node to better process mobility, provides seamless connection, and reduces the control overhead of the network, thereby saving energy.

Description

Design method of IPv6 mobile sensing route

Technical Field

The invention belongs to the technical field of wireless sensing, and relates to a design method of an IPv6 mobile sensing route.

Background

The IPv6 wireless sensor network has been developed for many years, and the related technology is mature, but the application scope thereof still has some limitations, especially in mobile scenarios. In industrial field application, a plurality of devices for mobile operation exist, and the IPv6 wireless sensor network is required to support mobility in industrial application. Recent advances in wireless sensor networks have resulted in many new routing protocols specifically designed for wireless sensor networks, where mobility is an essential consideration. The IETF-ROLL working group has standardized a routing protocol, referred to as the RPL routing protocol, for IPv6 low power consumption and lossy networks. The RPL standard does not consider mobility support, by design, and there is no mechanism in the standard specifically for or explicitly supporting mobility. The RPL routing protocol does not consider the router nodes to be mobile, only the leaf nodes. Many studies have shown that there is a significant performance degradation of mobility devices in the application of the RPL protocol because the RPL routing protocol cannot identify the mobile node and cannot provide any specific operation for the mobile node. Node movement may cause network topology changes, the Trickle timer value may be reset, and control message transmissions between nodes may increase rapidly. Meanwhile, detection delay occurs when the node moves, so that the RPL routing protocol cannot react quickly, and the connection of the mobile node and the loss of data are influenced. The important aspect is that the mobile node is fully involved in the mobility process, which results in a large amount of control overhead and energy consumption, so that the resources of the mobile node are rapidly reduced and the network fails rapidly. Therefore, the method is significant for the mobility research of the IPv6 wireless sensor network.

Disclosure of Invention

In view of the above, the present invention is directed to a method for designing mobility aware routing in IPv 6. The idea of the method is firstly to introduce an active handover procedure to recover the procedures caused by the node mobility and secondly to reduce the participation of the mobile node and the overhead of control messages for the whole network. First, it needs to improve the original RPL routing protocol, and the improved contents include: (1) the mobile node should select the preferred parent node to join the DODAG through the newly proposed objective function. (2) The parent node to which the mobile node connects is referred to as the associated node, which is considered to select a new associated node through an active process. (3) The mobile node is considered to be a leaf node that can be excluded from the routing path to avoid route disruption, and it does not participate in mobility handling. (4) Fields are added to ICMPv6 control messages (DIS, DIO), such as: RSSI with an average RSSI value and a flag to distinguish different usage types of messages, etc. (5) In order to update the downlink route, the DAO message is divided into two types, one is sent to a new predicted associated node to detect the availability of the new node, and the other is sent to the original associated node to delete the original path. Then the whole design method of the mobile sensing route is divided into three stages: a detection and transmission phase, a reaction and prediction phase and a notification phase. Detection and transmission phase: the associated node periodically calculates an average RSSI value from the data received from the mobile node. If the RSSI value is detected to have dropped below a predetermined threshold, the associated node concludes that the mobile node is already in a communication range away from itself and then triggers the next phase. Reaction and prediction phases: after the mobile detection, predicting a new associated node based on RSSI, wherein in the process, an original associated node sends DIS information (carrying mobile node MN _ ID) to a neighbor static node, the neighbor static node receiving the DIS information replies DIO information to the original associated node, and after the associated node receives the DIO information, the RSSI values of all nodes are compared, and the maximum node closest to the mobile node is selected as the predicted associated node. A notification phase: the original associated node informs the new associated node to the mobile node, and then completes the route update.

In order to achieve the purpose, the invention provides the following technical scheme:

a design method of mobility aware routing of IPv6, the method comprising the steps of:

s1: an active handover procedure is introduced to recover the procedures caused by the mobility of the nodes,

s2: the participation of the mobile node and the overhead of control messages for the entire network are reduced.

Optionally, the method specifically includes: the original RPL routing protocol is improved, which comprises the following steps:

(1) the mobile node should select a preferred parent node to join the DODAG through a newly proposed objective function;

(2) the parent node to which the mobile node connects is called an association node, which is considered to select a new association node through an active process;

(3) the mobile node is considered to be a leaf node that can be excluded from the routing path to avoid route disruption, and it does not participate in mobility handling;

(4) in the ICMPv6 control message, including DIS and DIO, some fields are added;

(5) in order to update the downlink route, the DAO message is divided into two types, one is sent to a new predicted associated node to detect the availability of the new node, and the other is sent to the original associated node to delete the original path; then the whole design method of the mobile sensing route is divided into three stages: a detection and transmission phase, a reaction and prediction phase and a notification phase;

detection and transmission phase: the associated node periodically calculates an average RSSI value through data received from the mobile node; if the RSSI value is detected to be reduced to a preset threshold value, the associated node deduces that the mobile node is away from the communication range of the associated node, and then triggers the next stage;

reaction and prediction phases: after mobile detection, predicting a new associated node based on RSSI (received signal strength indicator), wherein in the process, an original associated node sends DIS information, namely carrying a mobile node MN _ ID, to a neighbor static node, the neighbor static node receiving the DIS information replies DIO information to the original associated node, and after receiving the DIO information, the associated node compares RSSI values of all nodes and selects the maximum node closest to the mobile node as a predicted associated node;

a notification phase: the original associated node informs the new associated node to the mobile node, and then completes the route update.

Optionally, in a network in which the node moves, the fixed node and the mobile node exist at the same time, and if the mobile node serves as a root node, it may cause difficulty in network optimization, and transmission of a control message is significantly increased, and the mobile node is a default leaf node; configuring a mobile option on a node for distinguishing a mobile node from a fixed node;

some fields are added in the DIS message to ensure the normal processing related operations of the method, and a 2-bit flag field: when it is a simple request message, it equals "0"; setting the current associated node to "1" if it broadcasts a notification about mobility detection with it; when the mobile node uses it as the DIS message for the prediction phase, it will be set to "2"; when it is used to inform the predicted associated node, it will be set to "3"; and adds the MN _ ID field that the prediction phase would use to facilitate identification when a nearby neighbor detects it; adding an ARSSI field used in a detection stage for storing an RSSI value calculated between the mobile node and the current associated node;

when the flag is 0, the DIO message is a message of a lockle timer;

when the flag is 1, the predicted associated node sends a notice of changing the associated node to the mobile node by using the DIO message and processes a new associated node;

when flag is 2, the surrounding static neighbor nodes use the DIO message to calculate an RSSI value; adding an RSSI field, and using the RSSI field to carry RSSI values calculated by the mobile node and nearby neighbor nodes in a discovery phase;

when the node moving condition exists in the network, the link quality is in a weaker level, and the network is difficult to maintain an original stable routing path; the original objective function OF0 is replaced by the minimum rank MRHOF with a hysteresis objective function, the objective function adopts the expected transmission times ETX as the measurement, and experiments prove that the MRHOF can improve the overall throughput OF the mobile network; selecting an optimal parent node using the objective function; the Rank calculation formula in MRHOF is as follows:

Rank(N)＝Rank(P)+ETX(N)*128

where rank (n) is the rank of each node, and rank (p) is the rank of its parent node;

the expected number of transmissions ETX is the expected number of transmissions required for a node to successfully complete the task of delivering a data packet to its destination; ETX shows the link quality between the node and the neighbor node; ETX (N) is the ETX of its parent node;

ETX(N)＝ETX_old*β+ETX_new*(1-β)

where ETX is the old ETX value of the node and each node maintains in its routing table the old ETX, &lTtT translation = β "&gTt β &lTt/T &gTt is a learning ratio of 0.9 set by the RPL routing protocol default in Contiki, ETX is the old ETX value of the node and each node maintains in its routing table a learning ratio of 0.9 set by the RP_newThe calculation formula of (2) is as follows:

wherein d is_fIs the probability of successful transmission of a data packet, d_rIs the probability of the sender successfully receiving the acknowledgment packet; the lower the value of ETX, the more reliable the link quality;

the RSSI is used for measuring the measurement standard of the signal power of a radio frequency transceiver, reflects the signal strength of a link between a node and a neighbor node, and is measured by reading a built-in RSSI register on a radio chip CC 2420; averaging the RSSI values over at least eight symbol periods before position RSSI VALID is position 1; the RSSI is calculated as:

RSSI＝RSSI_VALUE+RSSI_OFFSET

where RSSI _ OFFSET front-end gain is determined empirically by the chip manufacturer.

Optionally, the detecting and transmitting stage is: this phase ensures the detection process by measuring the link quality during the data transmission;

step 11: the associated node periodically calculates an average RSSI value according to the data packet received from the mobile node;

step 12: when the RSSI value is detected to be reduced to a preset threshold value, the associated node deduces that the mobile node is far away from the communication coverage range of the associated node;

step 13: the associated node broadcasts a DIS message, i.e., flag 1, including the RSSI value and the mobile node ID field to surrounding neighboring nodes, and then the associated node triggers a timer of the DIOS Input for waiting to receive DIO messages of the mobile node and the surrounding nodes, i.e., flag 2.

Optionally, the reaction and prediction phase: in the stage, after the associated node detects that the node has moved, the associated node reserves the resources of the mobile node, predicts a new associated node for the mobile node, and simultaneously keeps the connection between the mobile node and the network, thereby ensuring quick switching and continuous connection;

step 21: the associated node broadcasts DIS message, namely after flag is 1, DIS message, namely flag is 1, is received by mobile node and other neighbor nodes;

step 22: when the mobile node receives the DIS message, that is, after flag is 1, the mobile node detects a received RSSI value;

step 23: if the RSSI value is less than or equal to the threshold value, the mobile node broadcasts a DIS message by triggering a DIS timer in order to enable the neighbor node to detect the mobile node, namely, the flag is 2 times, and the mobile node continues to send data packets;

step 24: if the RSSI value is less than or equal to threshold value-x, wherein x is a preset value, the mobile node is positioned at the boundary of the communication coverage range of the current associated node, and the mobile node stops sending data packets to avoid the loss of the data packets;

step 25: after receiving the DIS message, namely, after flag is 1, the neighbor node triggers a DIS message reception delay timer so as to detect the mobile node according to the received ID of the mobile node;

step 26: when the DIS message receiving delay timer expires, the neighbor node calculates an average RSSI value through the received DIS, namely, flag is 2, and then sends a unicast DIO message to the current associated node, namely, flag is 2, wherein the unicast DIO message carries the calculated average RSSI value;

step 27: the current associated node also receives a DIS message from the mobile node, namely, the flag is 2, and meanwhile, the average RSSI value is calculated;

step 28: when the timer of the DIOS Input in the first stage expires, the current associated node compares all received RSSI values, and selects a neighbor node with the maximum RSSI value as the predicted associated node.

Optionally, the notification phase: after the new associated node is predicted, the current associated node triggers a notification phase to execute the route update of the required path;

step 31: if the predicted associated node is the current associated node, the current associated node sends a notification of the completion of the processing to the mobile node;

step 32: if the predicted associated node is a new associated node, notifying the mobile node of the new associated node;

step 33: the predicted new associated node sends a unicast DIO message, namely, the flag is 1, to the mobile node;

step 34: after receiving the message, the mobile node updates and updates the parameters of the message, including a father node, a Rank and a default route to the root node;

step 35: then the mobile node sends two timely DAO messages to the original associated node and the predicted new associated node to update the routing path;

step 36: and when the mobile node is successfully connected with the predicted associated node, disconnecting the mobile node from the original associated node.

Optionally, when the three stages fail:

if the transmission stage or the detection fails, namely the current associated node misses the data packet received from the mobile node within the preset timer time, the method enters a no-data receiving process;

step 41: the current associated node broadcasts a DIO message within a predetermined DIO timer, namely, the flag is 0, to detect whether the mobile node is within the communication range of the current associated node;

step 42: if the mobile node is within the communication range of the current associated node, reconnecting;

step 43: if the DAO message is not received, the mobile node is not in the communication range of the current associated node; the current associated node broadcasts the DIS message, namely carries the ID of the mobile node, and sends the DIS message to the neighboring node, requesting the mobile node to broadcast the DIO message and trying to reconnect the mobile node;

if the prediction fails or the signaling message is lost in the switching process, the mobile node is triggered to participate in the process to recover the connection; this process would require the mobile node to participate in the mobility process and find a new associated node;

step 51: when the mobile node receives a DIS message from the current associated node, namely flag is 1, a detection connection timer is triggered;

step 52: if the timer expires and no new associated node is found, the mobile node broadcasts a DIS message, i.e., flag-0, to request DIO messages of surrounding neighbor nodes, i.e., flag-0;

step 53: if receiving DIO information from the neighbor node, namely, if flag is 0, reconnecting the mobile node and returning to the transmission stage; otherwise, step 52 is repeated.

The invention has the beneficial effects that:

when a node in a network moves, the link quality of the network is weak, and it is difficult to maintain a stable routing path, and meanwhile, the node moves to disconnect from a parent node, which may cause the node to reconnect to a new parent node, and this process may cause a large delay and packet loss, which affects the data transmission rate. The method aims to provide an active switching process, which can predict a new associated node before disconnection, reduce the energy consumption of a mobile node while providing seamless connection, avoid data loss and reduce switching delay.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is an overall frame diagram of the present invention;

FIG. 2 is a diagram illustrating operations associated with adding fields to DIS messages;

FIG. 3 is a DIO message frame format;

FIG. 4 is a schematic diagram of an association node;

FIG. 5 is a three phase diagram of mobility aware routing;

FIG. 6 is a flow chart of the detection and transmission phase algorithm;

FIG. 7 is a flow chart of the reaction and prediction phase algorithm;

FIG. 8 is a flowchart of an algorithm for the notification phase;

FIG. 9 is a diagram of a no data reception process;

fig. 10 is a diagram of a mobile node participation process.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

As shown in fig. 1, it is a mobility-aware routing design method of IPv 6.

In a network with mobile nodes, a fixed node and a mobile node exist simultaneously, if the mobile node is used as a node such as a root node, network optimization is difficult, transmission of control messages is remarkably increased, and therefore the mobile node is a leaf node by default. The mobility option is configured on the node with the aim of distinguishing between mobile and fixed nodes.

As shown in fig. 2, adding some fields in the DIS message ensures normal processing related operations of the method, and the flag field (2 bits): when it is a simple request message, it equals "0"; setting the current associated node to "1" if it broadcasts a notification about mobility detection with it; when the mobile node uses it as the DIS message for the prediction phase, it will be set to "2"; it will be set to "3" when it is used to inform the predicted associated node. And adds the MN _ ID field that the prediction phase would use to facilitate identification when it is detected by a nearby neighbor node. And adding an ARSSI field used in the detection stage for storing the RSSI value calculated between the mobile node and the current associated node.

DIO messages are used as carriers for information interaction between nodes, and some modification addition is needed in order to better adapt the method, and the frame format of the DIO messages is shown in fig. 3.

When the flag is 0, the DIO message is a message of a lockle timer; when the flag is 1, the predicted associated node sends a notice of changing the associated node to the mobile node by using the DIO message and processes a new associated node; when flag is 2, the surrounding static neighbor nodes use the DIO message to calculate the RSSI value. The RSSI field is added and used in the discovery phase to carry RSSI values calculated by the mobile node and nearby neighbor nodes.

When there is node movement in the network, the link quality will be at a weak level, and it will be difficult for the network to maintain an originally stable routing path. Therefore, the original objective function OF0 is replaced by the minimum rank with hysteresis objective function (MRHOF), which uses the expected transmission times (ETX) as a measure, and experiments prove that MRHOF can improve the overall throughput OF the mobile network. The optimal parent node is selected using the objective function. The Rank calculation formula in MRHOF is as follows:

Rank(N)＝Rank(P)+ETX(N)*128

where rank (n) is the rank of each node, and rank (p) is the rank of its parent node.

The expected number of transmissions (ETX) is the expected number of transmissions required for a node to successfully complete the task of delivering a data packet to its destination. ETX can well demonstrate the link quality between a node and a neighbor node. ETX (N) is the ETX of its parent node.

ETX(N)＝ETX_old*β+ETX_new*(1-β)

Where ETX is the old ETX value of the node, and each node maintains in its routing table the old ETX, &lTtT translation = β "&gTt β &lTt/T &gTt is a learning ratio of 0.9 set by the RPL routing protocol default in Contiki_newThe calculation formula of (2) is as follows:

wherein d is_fIs the probability of successful transmission of a data packet, d_rIs the probability that the sender successfully receives the acknowledgment packet.A lower value of ETX indicates a more reliable link quality. The expected transmission times (ETX) only consider packet loss rate of data packets, but do not consider link load and data transmission rate.

Signal received strength (RSSI) is a metric used to measure the signal power of a radio frequency transceiver. It plays an important role in a mobile environment, reflecting the signal strength of the link between a node and a neighboring node. It is measured by reading a built-in RSSI register on the radio chip CC 2420. The RSSI values are averaged over at least eight symbol periods before position RSSI VALID is assigned to position 1. The RSSI is calculated as:

RSSI＝RSSI_VALUE+RSSI_OFFSET

The original RPL protocol was first modified to enhance mobility implementation and to implement the required functionality. The modifications are as follows: (1) the mobile node should select the preferred parent node to join the DODAG through a predefined objective function. (2) The parent node to which the mobile node connects is referred to as the associated node, and the associated node is said to select a new associated node through an active process, as shown in fig. 4. (3) The mobile node is considered to be a leaf node that can be excluded from the routing path to avoid route disruption, and it does not participate in mobility handling. (4) Fields are added to ICMPv6 control messages (DIS, DIO), such as: RSSI with an average RSSI value and a flag to distinguish different usage types of the message. (5) In order to update the downlink route, the DAO message is divided into two types, one is sent to a new predicted associated node to detect the availability of the new node, and the other is sent to the original associated node to delete the original path.

In the initial stage, the mobile node selects the optimal father node of the mobile node based on the objective function and adds the optimal father node into the DODAG.

The mobile sensing route design method is divided into three stages: a detection and transmission phase, a reaction and prediction phase and a notification phase. The three stages are shown in fig. 5.

Detection and transmission phase: this phase ensures the detection process by measuring the link quality during the data transmission.

Step 1: the associated node periodically calculates an average RSSI value based on the packets received from the mobile node.

Step 2: upon detecting that the RSSI value has dropped below a predetermined threshold, the associated node may infer that the mobile node is moving away from its communication coverage (mobility detected).

And step 3: the associated node broadcasts a DIS message (flag 1) including the RSSI value and the mobile node ID field to surrounding neighbor nodes, and then the associated node triggers a timer of the DIOS Input for waiting for receiving DIO messages (flag 2) of the mobile node and the surrounding nodes.

The detection and transmission phase algorithm flow diagram is shown in fig. 6.

Reaction and prediction phases: in this stage, after the associated node detects that the node has moved, the associated node predicts a new associated node for the mobile node while maintaining the connection between the mobile node and the network, in order to reserve the resources of the mobile node, thereby ensuring fast handover and continuous connection.

Step 1: after the associated node broadcasts the DIS message (flag ═ 1), the DIS message (flag ═ 1) is received by the mobile node and other neighboring nodes.

Step 2: when the mobile node receives the DIS message (flag ═ 1), the mobile node detects the received RSSI value.

And step 3: if the RSSI value is less than or equal to the threshold value, the mobile node broadcasts a DIS message (flag ═ 2) three times by triggering a DIS timer in order for the neighbor nodes to detect itself, and continues to transmit data packets.

And 4, step 4: if the RSSI value is less than or equal to (threshold-x), where x is a predetermined value, it indicates that the mobile node is located at the boundary of the communication coverage area of the currently associated node, so the mobile node stops sending packets to avoid packet loss.

And 5: after receiving the DIS message (flag ═ 1), the neighbor node triggers a DIS message reception delay timer, so as to detect the mobile node according to the received ID of the mobile node.

Step 6: when the DIS message reception delay timer expires, the neighboring node calculates an average RSSI value through the received DIS (flag ═ 2), and then sends a unicast DIO message (flag ═ 2) to the current associated node, where the unicast DIO message carries the calculated average RSSI value.

And 7: the currently associated node also receives a DIS message (flag 2) from the mobile node while calculating the average RSSI value.

And 8: when the timer of the DIOS Input in the first stage expires, the current associated node compares all received RSSI values, and selects a neighbor node with the maximum RSSI value as the predicted associated node.

The reaction and prediction phase algorithm flow diagram is shown in fig. 7.

A notification phase: in the stage, after the prediction of the new associated node, the current associated node triggers a notification stage to perform the route update of the required path.

Step 1: if the predicted associated node is the current associated node, the current associated node sends a notification of the completion of the processing to the mobile node.

Step 2: if the predicted associated node is a new associated node, the mobile node is notified of the new associated node.

And step 3: the predicted new associated node sends a unicast DIO message (flag ═ 1) to the mobile node.

And 4, step 4: after receiving the message, the mobile node updates and updates its parameters (parent node, Rank, default route to the root node, etc.).

And 5: the mobile node then sends two timely DAO messages to the original associated node and the predicted new associated node to update the routing path.

Step 6: and when the mobile node is successfully connected with the predicted associated node, disconnecting the mobile node from the original associated node.

The notification phase algorithm is shown in fig. 8.

Accidents may occur in the above three stages, such as: expiration of the timer without receiving a message, failure of prediction, loss of signaling messages, etc. There are two solutions to the possible contingencies: there is no data reception procedure and no mobile node participation procedure.

In case of a transmission phase or a detection failure, i.e. the currently associated node misses receiving a data packet from the mobile node within a predetermined timer time, the method enters a no data reception procedure. As shown in fig. 9, the process is as follows:

step 1: the current associated node broadcasts a DIO message (flag ═ 0) within a predetermined DIO timer to detect whether the mobile node is within a communication range of the current associated node.

Step 2: if the mobile node is within communication range of the current associated node, the mobile node reconnects.

And step 3: if the DAO message is not received, it indicates that the mobile node is not within communication range of the current associated node. The current associated node broadcasts a DIS message (carrying the mobile node's ID) to neighboring nodes requesting the mobile node to broadcast a DIO message and attempt to reconnect the mobile node.

In the handover process, if the prediction fails or the signaling message is lost, the mobile node is triggered to participate in the process to recover the connection. This procedure would require the mobile node to participate in the mobility process and find a new associated node. The mobile node participation process is shown in fig. 10 as follows:

step 1: when the mobile node receives a DIS message (flag ═ 1) from the current associated node, a detect connection timer is triggered.

Step 2: if the timer expires and no new associated node is found, the mobile node broadcasts a DIS message (flag-0) to request DIO messages (flag-0) of surrounding neighbor nodes.

And step 3: if the DIO message from the neighbor node is received (flag is 0), the mobile node is reconnected and returns to the transmission phase. Otherwise, continuing to repeat the step 2.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.

Claims

1. A design method of mobility aware routing of IPv6 is characterized in that: the method comprises the following steps:

2. The method for designing mobility aware routing of IPv6 according to claim 1, wherein: the method specifically comprises the following steps: the original RPL routing protocol is improved, which comprises the following steps:

3. The method for designing mobility aware routing of IPv6 according to claim 1, wherein: in the network in which the nodes move, the fixed nodes and the mobile nodes exist simultaneously, if the mobile nodes are used as root nodes, the network optimization is difficult, the transmission of control messages is obviously increased, and the default mobile nodes are leaf nodes; configuring a mobile option on a node for distinguishing a mobile node from a fixed node;

when the flag is 0, the DIO message is a message of a lockle timer;

Rank(N)＝Rank(P)+ETX(N)*128

ETX(N)＝ETX_old*β+ETX_new*(1-β)

RSSI＝RSSI_VALUE+RSSI_OFFSET

4. The method for designing mobility aware routing of IPv6 according to claim 2, wherein: the detection and transmission phases are as follows: this phase ensures the detection process by measuring the link quality during the data transmission;

5. The method for designing mobility aware routing of IPv6 according to claim 2, wherein: the reaction and prediction phases: in the stage, after the associated node detects that the node has moved, the associated node reserves the resources of the mobile node, predicts a new associated node for the mobile node, and simultaneously keeps the connection between the mobile node and the network, thereby ensuring quick switching and continuous connection;

6. The method for designing mobility aware routing of IPv6 according to claim 2, wherein: the notification phase comprises the following steps: after the new associated node is predicted, the current associated node triggers a notification phase to execute the route update of the required path;

7. The method for designing mobility aware routing of IPv6 according to claim 2, wherein: when the three phases fail: