CN104349417B - The network-building method of regional submarine communication network based on short life cycle - Google Patents

Abstract

The present invention relates to a kind of network-building method of the regional submarine communication network based on short life cycle, including：The original state of each node is arranged to " unallocated state "；A node is selected, is broadcasted " cluster head broadcasting packet ", time-out time is set, oneself state is arranged to " applying to become cluster head "；Other nodes reply " adding cluster request message ", the node representated by source address are set to the leader cluster node of oneself, oneself state is revised as " cluster member " after " cluster head broadcasting packet " is received；The node of broadcast " cluster head broadcasting packet " receives " adding cluster request message " before the timeout, cancel timer, node representated by source address in " adding cluster request message " is set to cluster member, oneself state is set to " cluster head ", otherwise, oneself state is set to " unallocated state ", waits the broadcast " cluster head broadcasting packet " of next round, or receives " the cluster head broadcasting packet " transmitted by other nodes.

Description

Networking method of regional underwater communication network based on short life cycle

technical field

The present invention relates to the field of underwater acoustic network, in particular, the present invention relates to a networking method of a regional underwater communication network based on a short life cycle.

Background technique

The ocean occupies more than 70% of the earth's surface, with an average depth of 4km, and is rich in oil, gas, power minerals and other resources. At the same time, the ocean is the main channel of global transportation, the regulator of the global environment, and the birthplace and occurrence place of various natural disasters. Therefore, the ocean is an important strategic space for maintaining the sustainable development of human society and plays an important role in human development and social progress. All oceanic countries have successively invested a large amount of financial resources in the observation and development of the ocean in order to take the initiative in the control of ocean resources.

Compared with the wireless communication environment in the air, the underwater acoustic channel is a time-varying delay and Doppler double-diffusion channel, and the channel conditions are very harsh. The speed of sound in water is generally around 1500m/s, which is 5 orders of magnitude lower than the propagation speed of radio waves of 3.0×10 ⁸ m/s. In addition, the speed of sound is also affected by many factors such as temperature, salinity and pressure, and is comparable to the speed of the carrier and the fluctuation speed of the water surface, so the multi-path effect, Doppler frequency shift and time-varying channel are more obvious And complex. The harsh environment of underwater acoustic communication and the limitation of node functions affect the design of underwater acoustic network protocols, and it is necessary to develop more optimized network protocols according to different application scenarios.

According to whether routing information is known in advance, the network can be divided into two types: fixed network and self-organizing network.

In a fixed network, the positions of nodes are fixed, and strict measurements are generally carried out during deployment, and all routing information has been embedded in nodes before networking. Fixed routing is often used in the wireless field in centrally controlled networks where all nodes communicate directly with the gateway. In the field of underwater acoustics, fixed routing is also widely used, especially in combination with multiple access technologies such as TDMA and CDMA, which greatly improves network performance. However, fixed routing also has some problems, such as poor scalability and difficult node replacement, which cannot be applied to all scenarios.

In an ad hoc network, ad hoc routing protocols can be divided into proactive and feedback based on the route establishment time. In proactive routing, route establishment occurs during network initialization. Once the network is deployed, it immediately begins to establish all the routes that may be needed, regardless of whether the routing information will actually be used later. The routing information will be rebuilt periodically, and it doesn't care whether the rebuilt routing information will be used. Such agreements are represented by DSDV. Under feedback routing, only when a node needs to send a data packet to a node will the route to the node be established, and the data packet will be sent later. Routes that have not been used for a long time will be cleared regularly during route maintenance. Such agreements are represented by AODV.

Routing based on geographical location information determines the selection of routes according to the location of nodes in the network, which reduces the scope of data packet broadcasting in the process of route establishment. It not only reduces the waste of energy, but also reduces the probability of packet collision and communication delay. Routing based on geographic location information is represented by VBF.

The underwater acoustic network used for regional underwater communication with a short life cycle generally has the following characteristics: the network scale is small, the position of the nodes after deployment is relatively fixed, and the change of sound velocity and the drift of nodes will not cause major changes to the topology , but because the deployment accuracy is not easy to guarantee, the actual topological connection of the network cannot be known at the initial stage of deployment. Based on the above characteristics of the underwater acoustic network, the underwater acoustic network needs to adopt a self-organizing routing protocol. At the same time, because the topology of the underwater acoustic network is relatively fixed and the working time of the network is short (generally, a working process lasts about 8 minutes), there is no need to regularly clear old routes or update routes.

The route establishment delay of the AODV protocol in the prior art is relatively high, which will be further increased in an underwater acoustic network with a high propagation delay, and cannot meet the requirements of fast networking. The VBF protocol requires that the node can measure the angle of the signal sender, which cannot always be satisfied in underwater acoustic communication, so it cannot be used for the establishment of underwater acoustic network. Since the routes of each node in the underwater acoustic network do not need to be updated regularly, the DSDV protocol is not applicable.

Contents of the invention

The purpose of the present invention is to overcome the defect that the networking method of the underwater communication network in the prior art cannot meet the requirement of fast networking, so as to provide a fast networking method.

In order to achieve the above object, the present invention provides a method for networking of a regional underwater communication network based on a short life cycle, including:

Step 1), the initial states of each node to be networked are set to "unassigned state"; a node is selected from each node to be networked, and the node starts broadcasting a "cluster head broadcast message", Set the timeout period for the "waiting to join the cluster request message timer" on the node, and then set its own status to "applying to become a cluster head";

Step 2) After receiving the "cluster head broadcast message", other nodes in the network to be formed except the node broadcasting the "cluster head broadcast message" send the "cluster head broadcast message" to the nodes using the ALOHA method respectively Reply to the "Join Cluster Request Message", and set the node represented by the source address in the received "Cluster Head Broadcast Message" as its own cluster head node, and modify the node's own status to "cluster member";

Step 3), judge whether the node broadcasting the "cluster head broadcast message" has received any "join cluster request message" before the "waiting to join the cluster request message timer" expires, if received, perform the next step, otherwise , execute step 5);

Step 4), when the node that broadcasts the "cluster head broadcast message" receives any "join cluster request message" for the first time, cancel the timer, and send the source data in the received "join cluster request message" to The node represented by the address is set as its own cluster member, and the state of the node itself is set as "cluster head"; when the node receives the "join cluster request message" later, it will set the "join cluster request message" The source address in is set as its own cluster member, and the networking operation is ended after the "join cluster request message" is no longer received;

Step 5), the node that broadcasts the "cluster head broadcast message" sets its own state to "unassigned state", and then waits for the next round of broadcast "cluster head broadcast message", or receives the "cluster head broadcast message" sent by other nodes. broadcast message".

In the above-mentioned technical scheme, also include after described step 2):

Step a), other nodes in the network to be formed except for the node broadcasting the "cluster head broadcast message" have not received the "cluster head broadcast message", and the node broadcasts the "cluster head broadcast message" for the node Set the timeout period for the "Waiting to join the cluster request message timer", and then set its own status to "applying to become a cluster head";

Step b), after other nodes in the waiting network receive the "cluster head broadcast message", if the node's own status is already "cluster member", then there is no need to respond to the newly received "cluster head broadcast message" , if the node's own state is "cluster head", use ALOHA method to reply "forced to join the cluster message" to the source node that broadcasts the "cluster head broadcast message", and add the node to its own cluster membership table middle;

Step c), when the node broadcasting the "cluster head broadcast message" in step a) receives the "forced to join the cluster message", cancel the timer, and set the source address of the "forced to join the cluster message" Be its own cluster head node, and set the state to "cluster member".

In the above technical solution, in step 1), a random selection method is used to select a node from each node to be networked.

In the above technical solution, the "cluster head broadcast message" includes two fields, wherein the chb_type field includes 4 bits for indicating the message type; the chb_src field includes 4 bits for indicating the source address of the cluster head;

The "joining cluster request message" includes three fields, wherein the jcr_type field includes 4 bits, which are used to indicate the message type; the jcr_src field includes 4 bits, which are used to indicate the source address of the node to be added to the cluster; jcr_dst The field includes 4 bits and is used to represent the destination address of the node to be added to the cluster.

In the above technical solution, the "forced to join the cluster message" includes three fields, where fjr_type includes 4 bits for indicating the type of message, and fjr_src includes 4 bits for indicating the force to join the cluster The source address of the node, fjr_dst includes 4 bits, which is used to indicate the destination address of the node forcibly joining the cluster.

The advantages of the present invention are:

The invention can realize rapid networking of the underwater communication network, and is beneficial to improving the efficiency of underwater communication.

Description of drawings

Fig. 1 is the flowchart of the networking method of the present invention;

Figure 2 is a schematic diagram of an assembled underwater communication network in one embodiment.

detailed description

The present invention will be further described now in conjunction with accompanying drawing.

The networking method of the present invention is mainly aimed at the use environment where the network scale is small, the topology structure is relatively fixed, the working time is short, and synchronization and positioning are required.

Network topology is an important factor affecting network performance. The basic topology of the underwater acoustic network has two types: master-slave and peer-to-peer. In a master-slave network, all network nodes communicate through a central node. In a peer-to-peer network, each node can communicate with any other node directly or through relay nodes. When the number of nodes in the network is small, the master-slave network has the advantage of shorter route establishment time, and the communication with other nodes through a central node can meet the requirements. The networking method of the present invention uses a master-slave topology to create Hydroacoustic Network.

Before explaining the networking method of the present invention in detail, the data structure adopted in the present invention will be introduced first.

There are four possible states for the nodes in the underwater acoustic network: UNSSIGNED, CLUSTER_HEAD, CLUSTER_MEMBER, and TO_BE_HEAD; they represent unassigned state, cluster head, cluster member, and applying to become a cluster head respectively.

The nodes in the underwater acoustic network involve three kinds of command messages in the networking process: the cluster head broadcast message (hereinafter referred to as CHB), the joining cluster request message (hereinafter referred to as JCR), and the forced joining of the cluster message ( Hereinafter referred to as FJR). Among them, the data structure of CHB is shown in Table 1. The message includes two fields, wherein the chb_type field includes 4 bits for indicating the message type; the chb_src field includes 4 bits for indicating the source address of the cluster head . The data structure of JCR is shown in Table 2. The message includes three fields, wherein the jcr_type field includes 4 bits, which are used to indicate the message type; the jcr_src field includes 4 bits, which are used to indicate the node to be added to the cluster. Source address; the jcr_dst field includes 4 bits, which are used to indicate the destination address of the node to be added to the cluster. The data structure of FJR is shown in Table 3. The message includes three fields, of which fjr_type includes 4 bits, which is used to indicate the message type, and fjr_src includes 4 bits, which is used to indicate the source of the node that is forced to join the cluster The address, fjr_dst includes 4 bits, and is used to indicate the destination address of the node forcibly joining the cluster.

Table 1

Table 2

table 3

In one embodiment, as shown in Figure 2, a desired regional underwater communication network includes 3 nodes, these nodes are marked with 0, 1, and 2 respectively, and the distance between these nodes should not be greater than 100 meters . As shown in FIG. 1 , the networking method of the regional underwater communication network will be described below.

Step 1), the initial state of each node of network to be formed is all set to UNSSIGNED; Select a node from each node of described network to be formed, start to broadcast CHB by this node, be " waiting for JCR timer on this node "Set the timeout period, and then set its own state to "TO_BE_HEAD".

When a node is in the "TO_BE_HEAD" state, it will not respond to CHBs sent by other nodes. In this embodiment, the timeout time set for the "waiting for the JCR timer" is 2s, and in other embodiments, it can also be set to other values as required. In this step, the manner of selecting a node from multiple nodes is random, and in this embodiment, it is assumed that the selected node is node 1 .

Step 2), after other nodes in the network to be received except the node broadcasting the CHB receive the CHB, use the ALOHA method to reply to the JCR respectively to the node sending the CHB, and set the node represented by the source address in the received CHB to For its own cluster head node, modify the node's own state to CLUSTER_MEMBER.

In the above, it is assumed that the node sending CHB is node 1. Therefore, node 0 and node 2 in the network to be formed will use node 1 as their own cluster head node, and modify their status to CLUSTER_MEMBER.

Step 3), judging whether the node broadcasting the CHB has received any JCR before the "waiting for JCR timer" expires, if so, go to the next step, otherwise go to step 5).

Step 4), when the node broadcasting CHB receives any JCR for the first time, cancel the timer, set the node represented by the source address in the received JCR as its own cluster member, and set the node's own state Set it as CLUSTER_HEAD; when the node receives JCR later, it only needs to set the source address in the JCR as its own cluster member until it no longer receives the "join cluster request message" and then ends the networking operation.

Step 5), the node that broadcasts the CHB sets its state as UNSSIGED, and then waits for the next round of broadcasting the CHB, or receives the CHB sent by other nodes.

The above are the basic steps of the networking method of the present invention. Based on the particularity of the underwater acoustic network, there is still such a situation in practical applications: Among the nodes in the network to be formed except the node broadcasting the CHB, some nodes receive the CHB and successfully reply to the JCR, while other nodes may be due to the chain The road briefly failed and no CHB was received. At this time, these nodes that have not received the CHB will do as described in step 1): broadcast the CHB, set the timeout period for the "waiting for the JCR timer", and set their own status to "TO_BE_HEAD". In this case, the node that has set its own state to CLUSTER_MEMBER does not need to respond to the newly received CHB, and the node that has set its own state to CLUSTER_HEAD uses ALOHA to reply to the source node broadcasting CBH FJR, and add this node to its own in the cluster membership table. When the node broadcasting CBH receives the FJR, it cancels the timer, sets the source address of the FJR as its own cluster head node, and sets the state as CLUSTER_MEMBER.

For example, assume that node 0 receives CHB and successfully replies to JCR, node 2 does not receive CHB and then broadcasts CHB. At this time, since the state of node 0 is CLUSTER_MEMBER, it does not respond to any other CHB; while the state of node 1 is CLUSTER_HEAD, use the ALOHA method to reply FJR to the source node (that is, node 2) broadcasting CBH, and add node 2 to in its own cluster membership table. When node 2 receives the FJR, cancel the timer, set the source address of the FJR as its own cluster head node, and set the state to CLUSTER_MEMBER.

The above is the description of the steps of the networking method of the present invention. The time spent by the networking method of the present invention is analyzed below.

Suppose the duration of the chirp head is X seconds, the bit number of the data packet is PacketSize, the communication rate DataRate=600bps, and the maximum propagation delay is τ _max =0.0667 seconds, if the demodulation time and the CRC check of the data packet are not considered, Then the time for a packet to occur is approximately:

Unit: second.

The time to broadcast the "cluster head broadcast message (CHB)" is:

The time to send the "join cluster request message (JCR)" in ALOHA mode is:

In the same way, the time to send the "Force to join the cluster change message (FJR)" in ALOHA mode is:

Random backoff time +(2×X)+0.1867s.

According to the above time calculation method, in the example shown in Figure 2, suppose there are three nodes, and the positions of nodes 0, 1, and 2 are (0, 0), (0, 100), (50, 86.6) respectively. Using NS2 to simulate the above networking methods, the results are as follows:

(1) When the first node sends CHB with a random backoff time of 0s and no packet loss or collision occurs, the networking time is 2.058s;

(2) When one node sends CHB and the other two nodes reply to JCR at the same time, the JCR conflicts, and the MAC layer will increase the backoff window CW, and then send RTS after random backoff without conflicting, the networking time is 3.769s;

(3) When two nodes broadcast CHB at the same time, the CHB will collide. Since these two nodes are waiting for their own JCR, they will not respond to the CHB sent by the third node, so they need to wait for the next round of broadcast CHB , and the networking time is 4.958s.

(4) After node 1 broadcasts CHB, only node 0 receives CHB and successfully replies to JCR, while node 2 does not receive CHB due to short-term link failure. Using NS2 simulation, the networking time is 4.408s.

The present invention can basically complete networking within 5s, and can meet actual needs.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit them. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (5)

1. A networking method based on a short life cycle regional underwater communication network, comprising: Step 1), the initial states of each node to be networked are set to "unassigned state"; a node is selected from each node to be networked, and the node starts broadcasting a "cluster head broadcast message", Set the timeout period for the "waiting to join the cluster request message timer" on the node, and then set its own status to "applying to become a cluster head"; Step 2) After receiving the "cluster head broadcast message", other nodes in the network to be formed except the node broadcasting the "cluster head broadcast message" send the "cluster head broadcast message" to the nodes using the ALOHA method respectively Reply to the "Join Cluster Request Message", and set the node represented by the source address in the received "Cluster Head Broadcast Message" as its own cluster head node, and modify the node's own status to "cluster member"; Step 3), judge whether the node broadcasting the "cluster head broadcast message" has received any "join cluster request message" before the "waiting to join the cluster request message timer" expires, if received, perform the next step, otherwise , execute step 5); Step 4), when the node that broadcasts the "cluster head broadcast message" receives any "join cluster request message" for the first time, cancel the timer, and send the source data in the received "join cluster request message" to The node represented by the address is set as its own cluster member, and the state of the node itself is set as "cluster head"; when the node receives the "join cluster request message" later, it will set the "join cluster request message" The source address in is set as its own cluster member, and the networking operation is ended after the "join cluster request message" is no longer received; Step 5), the node that broadcasts the "cluster head broadcast message" sets its own state to "unassigned state", and then waits for the next round of broadcast "cluster head broadcast message", or receives the "cluster head broadcast message" sent by other nodes. broadcast message". 2. the networking method based on the regional underwater communication network of short life cycle according to claim 1, is characterized in that, after described step 2) also comprises: Step a), other nodes in the network to be formed except the node broadcasting the "cluster head broadcast message" have not received the "cluster head broadcast message", and the other nodes except the node broadcasting the "cluster head broadcast message" The node broadcasts the "cluster head broadcast message", sets the timeout period for the "waiting to join the cluster request message timer" on the node, and then sets its own state to "applying to become a cluster head"; Step b), after other nodes in the waiting network receive the "cluster head broadcast message", if the node's own status is already "cluster member", then there is no need to respond to the newly received "cluster head broadcast message" , if the node's own state is "cluster head", use ALOHA method to reply "forced to join the cluster message" to the source node that broadcasts the "cluster head broadcast message", and add the node to its own cluster membership table middle; Step c), when the node broadcasting the "cluster head broadcast message" in step a) receives the "forced to join the cluster message", cancel the timer, and set the source address of the "forced to join the cluster message" Be its own cluster head node, and set the state to "cluster member". 3. the networking method based on the regional underwater communication network of short life cycle according to claim 1 or 2, it is characterized in that, in described step 1), from each node of described pending networking A node is selected by random selection. 4. the networking method based on the regional underwater communication network of short life cycle according to claim 1 or 2, is characterized in that, described " cluster head broadcast message " comprises two fields, and wherein chb_type field comprises 4 bits, used to indicate the packet type; the chb_src field includes 4 bits, used to indicate the source address of the cluster head; The "joining cluster request message" includes three fields, wherein the jcr_type field includes 4 bits, which are used to indicate the message type; the jcr_src field includes 4 bits, which are used to indicate the source address of the node to be added to the cluster; jcr_dst The field includes 4 bits and is used to represent the destination address of the node to be added to the cluster. 5. the networking method of the regional underwater communication network based on short life cycle according to claim 2, it is characterized in that, described " forcibly joins this cluster message " comprises three fields, and wherein fjr_type comprises 4 bits, used to indicate the message type, fjr_src includes 4 bits, used to indicate the source address of the node that is forced to join the cluster, and fjr_dst includes 4 bits, used to indicate the destination address of the node that is forced to join the cluster.