CN101048012A - Method for deciding route at radio mesh network - Google Patents

Abstract

The invention discloses a method for determining a route in a wireless mesh network, comprising: setting different routing decision-making strategies for different service types; The corresponding route decision policy and the path information in each route response determine the route corresponding to this service. The present invention adopts different routing strategies for different business types to determine the route, therefore, it can ensure that the data transmission of each business type between the source node and the destination node can meet the service quality requirements of the business, and make full use of network resources , thereby greatly improving the performance of the network.

Description

A Method of Determining Routing in Wireless Mesh Network

technical field

The invention relates to network communication technology, in particular to a method for determining routing in a wireless mesh network (Wireless Mesh Network, WMN).

Background technique

WMN is a new broadband wireless network structure and a high-capacity, high-speed distributed wireless network. In the WMN network, the parent routing protocol used for business data transmission is mainly the Dynamic Source Routing (Dynamic Source Routing, DSR) protocol.

Fig. 1 is a flowchart of determining a route between two nodes in the prior art. Referring to Fig. 1, in the current WMN network, when a source node, such as source node A, needs to determine a route to a destination node, such as destination node C, the prior art uses the DSR protocol to determine the route between source node A and destination node C. The process of inter-routing includes the following steps:

Step 101: The source node A sends a routing request (Route Request, RREQ) for the destination node C by broadcasting.

Here, the routing request may include: the life cycle TTL of the broadcast routing request (generally a hop limit), the packet sequence number of the routing request, the address information of the source node itself, the address information of the destination node, and the like.

Step 102: The intermediate node B receives the routing request, and judges whether the currently received routing request should be discarded, and if so, ends the current process; otherwise, executes step 103.

Here, the process for the intermediate node B to determine whether the currently received routing request should be discarded is as follows: the intermediate node B determines whether it has ever received the routing request sent by the source node A to the destination node C, if it has not received it, Then think that the currently received routing request should not be discarded, if once received, then judge whether the packet sequence number of the previously received routing request is greater than or equal to the packet sequence number of the currently received routing request, if yes, then It is determined to discard the currently received routing request, otherwise it is considered that the currently received routing request should not be discarded.

Step 103: The intermediate node B carries the route information of this node in the received routing request, and then sends the current routing request to the destination node C.

It should be noted that since in step 101, the source node A broadcasts the routing request, the routing request will be transmitted through multiple paths, and on each path, the processing process of each intermediate node is as shown in Figure 1. The processing procedure of Node B. Correspondingly, the routing requests received by the destination node are multiple routing requests carrying different path information sent by different intermediate nodes on different paths.

Step 104: When the destination node C receives each routing request, it carries the path information collected by the node in the routing request.

Step 105: When the destination node C receives each routing request, it carries all the path information in the routing request and sends it to the source node A in a routing response.

Step 106: After receiving the route responses, the source node A determines the route with the least number of node hops as the route for this service type according to all the route information carried in the route responses.

Step 107: The source node A sends the current service data to the destination node C through the determined route with the least number of node hops.

From the process shown in Figure 1 above, it can be seen that when the source node receives the routing response carrying various path information, no matter what type of business this service is, the route determined by the source node is the path with the least number of node hops. In the subsequent process, when the source node sends the service data of this service type, it transmits according to the determined path with the least number of node hops.

However, one of the business characteristics of the current WMN is to provide multimedia business services, that is, data of various types of business can be transmitted in the WMN network, for example, business data of voice type, business data of video type, text type Business data and best-effort type business data, etc. For data of different business types, the requirements for business service quality are different.

It can be seen that the existing technology does not distinguish between different business types, but adopts the same routing strategy, that is, the method of determining the route according to the path with the least number of node hops, which cannot satisfy the requirements for different business types of data. The different requirements of service quality cannot make full use of network resources, thus greatly reducing the performance of the network.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for determining routing in WMN, so as to determine the optimal path satisfying the service quality requirements for different service types.

In order to achieve the above object, the technical solution of the present invention is achieved in that:

A method for determining routing in a wireless mesh network, the method comprising: setting different routing decision strategies for different business types; after receiving multiple routing responses carrying path information, the source node The route decision policy and the path information carried in each route response determine the route corresponding to this service.

Before the source node receives multiple routing responses carrying path information, it further includes:

A. After each intermediate node receives the routing request sent by the source node through broadcast, it updates the path information in the routing request according to the path information collected by the node;

B. Each intermediate node sends the current routing request to the destination node respectively;

C. After the destination node receives each routing request, it updates the path information in the routing request according to the path information collected by the node, and then carries the path information carried in each routing request in each routing response and sends it to source node.

Between step A and step B, it further includes: each intermediate node judges whether the routing request sent to the destination node by the source node has been received, and if so, whether the packet sequence number of the routing request once received is judged Equal to the packet sequence number of the currently received routing request, if yes, then judge whether the path of the currently received routing request is better than the path of the previously received routing request, if better, then perform step B, if not If so, end the current process.

The type of this service is voice;

The judging whether the path of the currently received routing request is better than the previously received path of the routing request includes: judging whether the number of node hops from the source node to the intermediate node in the currently received routing request is less than that of the previously received routing request The number of node hops from the source node to the intermediate node in the received routing request, if yes, then determine that the path of the currently received routing request is better than the path of the previously received routing request, otherwise, determine The path of the currently received routing request is no better than the path of the previously received routing request.

The type of this business is video;

In step A, the step of updating the path information in the routing request according to the path information collected by this node includes: combining the remaining bandwidth information Bw _i from the previous hop node to the intermediate node with the information carried in the currently received routing request After taking the minimum value of the original Min_Bw, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the intermediate node with the currently received After the original PDR carried in the routing request is multiplied, use the multiplied result to update the value of the PDR in the currently received routing request,

Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _N-1 ), the updated

$\mathrm{PDR}=\underset{i=1}{\overset{i=N-1}{\mathrm{\Π}}}\mathrm{rd}{r}_{i,i+1},$ And N is the number of nodes from the source node to the intermediate node in the path, Bw _i is the statistical residual bandwidth of the i-th node from the source node to the intermediate node, pdr _{i, i+1} is from the source node to the The delivery rate from the i-th node to the i+1-th node among the intermediate nodes;

The judging whether the path of the currently received routing request is better than the path of the previously received routing request includes:

100. The intermediate node respectively obtains the value of Min_Bw and the value of PDR from the currently received routing request and the previously received routing request, and uses the formula W ₁ =α·Min_Bw+β·PDR to calculate the The currently received routing request and the _W value of the previously received routing request, where α and β are weighting factors;

101. The intermediate node judges whether the W ₁ value of the currently received routing request is greater than the W ₁ value of the previously received routing request, and if so, determines that the route of the currently received routing request is better than that of the previously received routing request. Otherwise, determine that the path of the currently received routing request is not better than the path of the previously received routing request.

The type of this business mentioned is best effort;

In step A, the step of updating the path information in the routing request according to the path information collected by this node includes: combining the remaining bandwidth information Bw _i from the previous hop node to the intermediate node with the information carried in the currently received routing request After taking the minimum value of the original Min_Bw, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the intermediate node with the currently received After the original PDR carried in the routing request is multiplied, the result obtained after the multiplication is used to update the value of the PDR in the currently received routing request, and the load information Load _i of the intermediate node is carried in the currently received routing request. After taking the maximum value of the original Max_Load, use the maximum value to update the value of Max_Load in the currently received routing request, wherein, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _N-1 ),after the update $\mathrm{PDR}=\underset{i=1}{\overset{i=N-1}{\mathrm{\Π}}}{\mathrm{pdr}}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _N ), and N is the number of nodes from the source node to the intermediate node in the path, and Bw _i is from the source node to the The statistical remaining bandwidth of the i-th node in the intermediate nodes, pdr _{i, i+1} is the delivery rate from the source node to the i-th node to the i+1-th node in the intermediate nodes, and Load _i is the delivery rate from the source node to the load of the i-th node in the intermediate nodes;

The judging whether the path of the currently received routing request is better than the path of the previously received routing request includes:

110. The intermediate node respectively obtains Max_Load, Min_Bw and PDR from the currently received routing request and the previously received routing request, and uses the formula W ₂ =γ·Max_Load+λ·Min_Bw+v·PDR to calculate respectively Get the W ₂ value for the currently received routing request and the routing request once received, where γ, λ and v are weighting factors;

111. The intermediate node judges whether the W ₂ value of the currently received routing request is greater than the W ₂ value of the previously received routing request, and if so, determines that the route of the currently received routing request is better than the previously received routing request. The path of the received routing request, otherwise, determine that the currently received path of the routing request is not better than the path of the previously received routing request.

After each intermediate node judges that the path of the routing request currently received is better than the path of the previously received routing request, and before performing step B, it further includes: each intermediate node respectively judges its own current resource status Whether to allow forwarding, if yes, execute step B, otherwise, end the current process.

After each intermediate node judges that the path of the currently received routing request is better than the path of the previously received routing request, and before performing step B, it further includes: each intermediate node judges whether its own queue length is greater than the preset length threshold, if yes, end the current process; otherwise, execute step B.

After each intermediate node determines that the path of the currently received routing request is better than the previously received path of the routing request, and before performing step B, it further includes: each intermediate node respectively according to the currently received route The life cycle carried in the request determines whether the currently received routing request has expired, if so, ends the current process, otherwise executes step B.

After each intermediate node judges that the path of the routing request currently received is better than the path of the previously received routing request, and before performing step B, it further includes: each intermediate node searches for its own route respectively Cache, judging whether there is a path from itself to the destination node in the routing cache, if not, then directly execute step B, if it exists, then judging whether the path from itself to the destination node in the routing cache is better than the currently received The path carried in the routing request, if it is, each intermediate node integrates the path information from itself to the destination node in the routing cache and all the path information in the currently received routing request, and carries it in each routing response and sends it to the source node, otherwise, go to step B directly.

The method further includes: setting a routing criterion structure for storing path performance information in the TARP packet header of the routing request;

The step of carrying the path information in the routing request includes: integrating the path information collected by this node with the existing path information in the currently received routing request and carrying it in the TARP packet header of the currently received routing request In the routing criterion structure.

Said setting different routing decision-making strategies for different business types includes: for the voice service type, setting the corresponding routing decision-making strategy is to select the route with the least number of node hops; for the video service type, setting the corresponding routing decision-making strategy is to select the delivery For the best-effort business type, set the corresponding routing decision-making strategy to select a route with a smaller node load, a larger remaining bandwidth, and a better delivery rate.

The type of this service is voice;

The step of determining the route corresponding to this service includes: the source node selects the route with the least node hops corresponding to the voice of this service type, and the node hop information carried in the response of each route, and selects the corresponding least node The route response of the hop count, and the address information of each node carried in the selected route response is determined as the route corresponding to this service.

The type of this business is video;

The step of updating the path information in the routing request according to the path information collected by the node includes: after the remaining bandwidth information Bw _i from the last hop node to the node and the original Min_Bw in the currently received routing request get the minimum value, use The minimum value updates the Min_Bw value in the currently received routing request, and after multiplying the delivery rate information pdr _{i, i+1} from the previous hop node to the current node by the original PDR carried in the currently received routing request, Update the value of the PDR in the currently received routing request with the result of the multiplication,

Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _n-1 ), the updated

$\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}\mathrm{pd}{r}_{i,i+1},$ And n is the number of nodes from the source node to the node in the path, _Bwi is the statistical residual bandwidth from the source node to the i-th node in the node, and pdr _{i, i+1} is from the source node to the node. The delivery rate from the i-th node to the i+1-th node in the current node;

The step of determining the route corresponding to this service includes: the source node selects a route with an excellent delivery rate and remaining bandwidth according to the video corresponding to this service type, and the minimum remaining bandwidth information Min_BW and The delivery rate information PDR selects a route response corresponding to both the delivery rate and the minimum remaining bandwidth, and determines the address information of each node carried in the selected route response as the route corresponding to this service.

The step of selecting a route response corresponding to an excellent delivery rate and minimum remaining bandwidth includes: the source node respectively obtains path minimum remaining bandwidth information Min_Bw and path delivery rate information PDR from each route response, and uses the formula W ₁ =a· Min_Bw+β·PDR, respectively calculate the W ₁ value for each routing response, where α and β are weighting factors, and select the routing response corresponding to the largest W ₁ value.

The type of this business mentioned is best effort;

The step of updating the path information in the routing request according to the path information collected by this node includes: taking the minimum value of the remaining bandwidth information Bw _i from the last hop node to the current node and the original Min_Bw carried in the currently received routing request Afterwards, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the current node with the original PDR carried in the currently received routing request After multiplication, use the multiplied result to update the value of the PDR in the currently received routing request, and after taking the maximum value of the load information Load _i of this node and the original Max_Load carried in the currently received routing request, use the The maximum value updates the value of Max_Load in the currently received routing request,

Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _n-1 ), the updated

$\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}\mathrm{pd}{r}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _n ), and n is the number of nodes from the source node to the node in the path, and Bw _i is from the source node to the node. Describe the statistical residual bandwidth of the i-th node in this node, pdr _{i, i+1} is the delivery rate from the source node to the i-th node to the i+1-th node in the said node, and Load _i is the delivery rate from the source node The load to the i-th node in the current node;

The step of determining the route corresponding to this service includes: the source node chooses the route corresponding to the best effort of the service type according to the current service type, which has a smaller node load and has a larger remaining bandwidth and a better delivery rate, and each route responds The minimum remaining bandwidth information Min_Bw, the maximum load information Max_Load, and the delivery rate information PDR of the path respectively carried in , select the route response with a relatively small load of the corresponding node and have a large remaining bandwidth and a better delivery rate, and respond to the selected route The address information of each node carried in , is determined as the route corresponding to this service.

The step of selecting a routing response corresponding to a node with a relatively small load and having a large remaining bandwidth and a better delivery rate includes: the source node respectively obtains the minimum remaining bandwidth information Min_Bw, the maximum load information Max_Load, and the delivery rate of the path from each routing response Rate information PDR, use the formula W ₂ =γ·Max_Load+λ·Min_Bw+v·PDR to calculate the W ₂ value for each route response, where γ, λ and v are weighting factors, choose the maximum W ₂ value The corresponding routing response.

This shows that the present invention has the following advantages:

1. The present invention uses different routing strategies to determine routes for different business types, so it can ensure that the transmission of each business type data between the source node and the destination node can meet its business service quality requirements, and make full use of Network resources, thus greatly improving the performance of the network.

2. In the present invention, for some specific service types, such as video service types and best-effort service types, since the delivery rate between nodes is considered when determining their routes, if the nodes are in a service hot spot , that is, if the delivery rate between nodes is small, the determined route can be avoided from the hotspot area, thereby meeting the load balancing requirement of the WMN network.

3. In the present invention, for some specific service types, such as best-effort service types, since the maximum load of the nodes is considered when determining its route, if the load of the nodes is relatively large, all The determined route avoids the node, so that the node with a large load can ensure the normal communication of the existing connection, thereby providing service guarantee for the connected users.

4. In the present invention, the routing information of each type of service, such as delivery rate and maximum load, etc. is obtained through the routing request, based on the statistics of each node's interaction with the inherent information of the network, without the need for other Business process or signaling to obtain, therefore, saving network bandwidth resources.

5. In the present invention, since different routing strategies are used to determine routes for different business types, it can be ensured that data of different business types between the same source node and destination node are transmitted through different paths, that is, multiple routes are realized. Therefore, the present invention has the advantages of multi-path data transmission, such as load balancing and the like.

Description of drawings

Fig. 1 is a flowchart of determining a route between two nodes in the prior art.

Fig. 2 is a flowchart of determining a route between two nodes in an embodiment of the present invention.

Fig. 3 is a flow chart of an intermediate node determining whether to discard a currently received routing request in an embodiment of the present invention.

Detailed ways

The core idea of the present invention is to set different routing decision-making strategies for different business types; after the source node receives multiple routing responses carrying path information, it determines the corresponding routing strategy for this business according to the routing decision-making strategy corresponding to this business type routing.

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 2 is a flowchart of determining a route between two nodes in an embodiment of the present invention. Referring to Fig. 2, when a source node, such as source node A, needs to determine the route to a destination node, such as destination node C, the present invention realizes that the process of determining the route includes the following steps:

Step 201: Different routing decision-making strategies are set in advance for different service types.

Here, in order to better meet the different requirements of each business type on business service quality, different routing decision-making strategies must be set for different business types, that is, different business types determine their transmission routes according to different routing decision-making strategies .

Specifically, taking the business types shown in Table 1 below as an example, business type voice video do your best

Table 1

See Table 1. For voice-type business data, in order to ensure the continuity of the call, the minimum transmission delay is required. That is to say, when determining the route, the path with the least number of hops from the source node to the destination node should be selected. The shortest route; for video-type business data, in order to ensure the clarity of the image and the requirements for network bandwidth, it is required to find a path with excellent delivery rate and remaining bandwidth; for best-effort business data, since there is no special business Quality requirements, so we should look for paths with less node load and larger remaining bandwidth, so as to make full use of network resources. Therefore, for the convenience of description, the formula shown in Table 2 below can be used to reflect the routing decision policy of each service type in Table 1. business type Routing Policy Formula voice W ₀ =Hops video W ₁ =α·Min_Bw+β·PDR do your best W ₂ =γ·Max_Load+λ·Min_Bw+v·PDR

Table 2

See Table 2, where Hops is the number of node hops; Min_Bw refers to the minimum bandwidth of links between all nodes in the path, that is, the available bandwidth of the path; PDR is the delivery rate of the path; Max_Load is the maximum load of nodes in the path; α, β, γ , λ and v are the weighting factors of each part. Preferably, the value of |α|+|β| is 1, and the value of |γ|+|λ|+|v| is 1. In addition, the expressions of the path minimum bandwidth, path maximum load and path maximum delivery rate are as follows: Max_Load=max(Load ₁ , Load ₂ ,...,Load _i ,...,Load _n ), Min_Bw=min(Bw ₁ , Bw ₂ , ...Bw _i ,...,Bw _n-1 ), $\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}\mathrm{pd}{r}_{i,i+1},$ And n is the number of nodes from the source node to the destination node in the path, Load _i is the load of the i-th node, Bw _i is the statistical residual bandwidth of the i-th node, pdr _{i, i+1} is the The delivery rate of i+1 nodes.

Step 202: The source node A broadcasts a routing request for the destination node C.

Here, the routing request may include: the life cycle TTL of the broadcast routing request (generally hop limit), the packet sequence number of the routing request, the service type of this service, the address information of the source node itself and the destination node address information, etc. Moreover, the present invention can set a routing criterion structure in the Traffic Aware Routing Protocol (TARP) header of the routing request to store the performance parameters of the path.

Step 203: After receiving the routing request, the intermediate node B updates the path information in the routing criterion structure of the received routing request according to the path information collected by the node.

Here, the specific implementation process of this step includes: after the intermediate node B receives the routing request, it takes the minimum value of the remaining bandwidth information Bw _i from the last hop node to the current node B and the original Min_Bw carried in the currently received routing request, Use this minimum value to update the Min_Bw value in the currently received routing request, and multiply the delivery rate information pdr _{i, i+1} from the previous hop node to the current node B by the original PDR carried in the currently received routing request Afterwards, use the multiplication result to update the value of the PDR in the currently received routing request, and after taking the maximum value of the load information Load _i of the current node B and the original Max_Load carried in the currently received routing request, use the The maximum value updates the value of Max_Load in the currently received routing request, wherein, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _N-1 ), the updated $\mathrm{PDR}=\underset{i=1}{\overset{i=N-1}{\mathrm{\Π}}}\mathrm{pd}{r}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _N ), and N is the number of nodes from the source node to the intermediate node B in the path, and _Bwi is the number of nodes from the source node to the intermediate node B. Statistical residual bandwidth of the i-th node in the intermediate node B, pdr _{i, i+1} is the delivery rate from the source node to the i-th node in the intermediate node B to the i+1-th node, Load _i is The load from the source node to the i-th node in the intermediate node B;

Then, the updated Min_Bw value, PDR value, Max_Load value and the address information of the current node B are carried in the routing criterion structure in the received routing request.

Step 204: The intermediate node B receives the routing request, and judges whether the currently received routing request should be discarded, and if so, ends the current process; otherwise, executes step 205.

Here, the specific implementation process of this step can be seen in Figure 3, including the following steps:

Step 301: The intermediate node B judges whether it has ever received the routing request sent by the source node A to the destination node C according to the source address information and destination address information in the currently received routing request, and if so , then execute step 302, otherwise, consider that the currently received routing request should not be discarded, and directly execute step 205.

Step 302: The intermediate node B judges the size relationship between the packet sequence number of the routing request that has been received and the packet sequence number of the currently received routing request, if the packet sequence number of the routing request that has been received is greater than the packet sequence number currently received If the packet sequence number of the routing request is determined, the currently received routing request is discarded, and the current process is ended. If the packet sequence number of the routing request that has been received is less than the packet sequence number of the currently received routing request, then step 303 is performed. If the packet sequence number of the previously received routing request is equal to the currently received packet sequence number of the routing request, step 304 is executed.

Here, if the packet sequence number of the routing request that has been received is greater than the packet sequence number of the currently received routing request, it means that the currently received routing request is an outdated routing request, and it is not that the source node A is in order to determine this service. Therefore, the subsequent process of determining the route should not be adopted, that is, the currently received routing request is discarded, and the current process is ended.

If the packet sequence number of the routing request that has been received is smaller than the packet sequence number of the currently received routing request, it means that the currently received routing request is sent by the source node A received for the first time to determine the route of this service Routing requests, so the subsequent process of determining routing should be performed directly.

If the packet sequence number of the routing request that has been received is equal to the packet sequence number of the currently received routing request, it means that a route from the source node A to the node B has been received before, such as the route ADB. The routing request to determine the route of this service is currently received from another route from source node A to node B, such as route AEB, and the routing request to determine the route of this service is sent. Therefore, In order to achieve the purpose of the present invention to select the optimal route that meets the network performance requirements for different service types, the subsequent process of determining the optimal route according to the current service type must be performed, that is, step 304 is performed.

Step 303: The intermediate node B uses the packet sequence number of the currently received routing request to update the packet sequence number of the routing request from the source node A to the destination node C stored by itself, and directly executes step 205.

Step 304: The intermediate node B judges whether the path of the currently received routing request is better than the path of the previously received routing request, if yes, then directly execute step 205, otherwise, determine to discard the currently received routing request, and end current process.

Here, the judgment specifically includes: the intermediate node B determines the routing decision corresponding to the current service type according to the service type of the current service carried in the currently received routing request and the different routing decision strategies of different service types preset Strategy; the intermediate node B makes a judgment according to the determined routing decision-making strategy corresponding to the current service type, as well as the currently received routing request and the path information carried in the routing criterion structure in the previously received routing request .

Referring to Table 1 and Table 2, for example, the service type of this service is a voice service type, and the formula corresponding to the voice service type is W ₀ =Hops, and its routing strategy is to select the shortest path with the smallest value of W ₀ , that is, the passed The path with the least number of node hops. Therefore, in this step, the intermediate node B determines the route from source node A to this node B according to the currently received routing request and the node hop information in the previously received routing request. , the number of node hops passed by the currently received routing request and the previously received routing request respectively. If the currently received routing request passes through less node hops than the previously received routing request, the current The path information carried in the received routing request is better than the path information carried in the previously received routing request.

For another example, the service type of this service is a video service type _, and the formula corresponding to the video service type is W ₁ =α·Min_Bw+β·PDR. satisfies the minimum link bandwidth and the maximum delivery rate path, therefore, in this step, the intermediate node B according to the currently received routing request and the updated Min_Bw in the routing criterion structure in the previously received routing request value and the value of PDR, use the formula W ₁ =α·Min_Bw+β·PDR to calculate the correspondence between the currently received routing request and the previously received routing request when traveling from source node A to local node B The _W1 value. If the W ₁ value corresponding to the currently received routing request is greater than the previously received routing request, it is considered that the path information carried in the currently received routing request is better than the path information carried in the previously received routing request .

For another example, the service type of this service is best effort, and the formula corresponding to the best effort service type is W ₂ =γ·Max_Load+λ·Min_Bw+v·PDR, therefore, in this step, the intermediate node B according to For the currently received routing request and the updated Min_Bw value, PDR value and Max_Load value in the routing criterion structure in the routing request received, use W ₂ =γ·Max_Load+λ·Min_Bw+v· The PDR calculates the W ₂ values corresponding to the currently received routing request and the previously received routing request when traveling from the source node A to the local node B. If the _W2 value corresponding to the currently received routing request is greater than the previously received routing request, it is considered that the path information carried in the currently received routing request is better than the path information carried in the previously received routing request .

So far, the process of judging whether the currently received routing request should be discarded has been realized.

Step 205: The intermediate node B judges whether its current resource status allows forwarding, if yes, executes step 206, otherwise, ends the current process.

Here, the resource status may include: the remaining bandwidth, the delivery rate from the upstream node to the current node, and the like.

Step 206: The intermediate node B judges whether its own queue length is greater than a preset length threshold, if yes, ends the current process, otherwise, executes step 207.

Step 207: The intermediate node B judges whether the currently received routing request has expired according to the life cycle TTL in the currently received routing request, and if so, ends the current process; otherwise, executes step 208.

The above step 205, step 206 and step 207 do not have a fixed execution sequence, but are just different steps split for the convenience of description.

In addition, the processes of step 205, step 206 and step 207 limit the number of forwarding routing requests, thereby reducing the protocol overhead of the network.

Step 208: The intermediate node B searches its own routing cache, and judges whether there is a path from itself to the destination node C in the routing cache, if yes, executes step 209, otherwise, executes step 211.

Step 209: The intermediate node B judges whether the path information from itself to the destination node C in the routing cache is better than the path information carried in the currently received routing request, if yes, execute step 210, otherwise, directly execute step 211.

Here, the principle of the judging process is exactly the same as the process described in step 304 .

Step 210: The intermediate node B uses all the path information in the current routing request routing criterion structure to update its own routing cache, and then updates the path information from itself to the destination node C in the routing cache and the currently received routing request routing criteria The path information in the structure is carried in the routing response and sent to the source node A, and step 214 is directly executed.

Step 211: The intermediate node B uses all the path information in the routing criterion structure of the current routing request to update its own routing cache, and then sends the current routing request to the destination node C.

It should be noted that, since in step 201, the source node A broadcasts the routing request, the routing request will be transmitted through multiple paths, and on each path, the processing process of each intermediate node is just like that of the above-mentioned intermediate node B. process. Correspondingly, the routing requests received by the destination node are multiple routing requests carrying different path information sent by intermediate nodes on different paths.

Step 212: When the destination node C receives each routing request, it carries the path information of this node in the routing criterion structure in the routing request.

Here, the specific implementation process of this step includes: After taking the minimum value of the remaining bandwidth information Bw _i from the last hop node to the current node C and the original Min_Bw carried in the currently received routing request, use the minimum value to update the currently received The Min_Bw value in the routing request, and multiply the delivery rate information pdr _{i, i+1} from the last hop node to the current node C by the original PDR carried in the currently received routing request, and use the multiplied result Update the value of the PDR in the currently received routing request, and after taking the maximum value of the load information Load _i of the node C and the original Max_Load carried in the currently received routing request, use the maximum value to update the currently received routing The value of Max_Load in the request,

Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _n-1 ), the updated

$\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}\mathrm{pd}{r}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _n ), and n is the number of nodes from the source node A to the destination node C in the path, and Bw _i is from the source node A to the statistical residual bandwidth of the i-th node in the destination node C, pdr _{i, i+1} is the delivery rate from the source node A to the i-th node in the destination node C to the i+1th node, Load _i is the load from the source node A to the i-th node in the destination node C;

Then, the destination node C carries the updated Min_Bw value, PDR value, Max_Load value and the address information of the current node C in the routing criterion structure in the received routing request.

Step 213: When the destination node C receives each routing request, it carries all the path information in the routing criterion structure in the routing request and sends it to the source node A in a routing response.

Here, the path traversed by the destination node C when sending the routing response to the source node A is opposite to the path traversed by the corresponding routing request received. Moreover, during the process of sending the routing response to the source node A, when each intermediate node receives the routing response, it can further obtain relevant path information from the routing response and save it in its own routing cache.

Step 214: After receiving each route response, the source node A determines the optimal route corresponding to the current service type according to all the path information carried in each route response.

Here, since each routing response carries all path information that its corresponding routing request passes through, including: updated Min_Bw value, PDR value, Max_Load value, and address information of each node. Therefore, the specific implementation process of this step includes: the source node A determines the routing decision-making strategy corresponding to the current business type according to the different routing decision-making strategies of different business types set in advance; The routing decision-making strategy and the path information carried in each routing response are used for judgment.

Referring to Table 1 and Table 2, for example, the service type of this service is a voice service type, and the formula corresponding to the voice service type is W ₀ =Hops, and its routing strategy is to select the shortest path with the smallest value of W ₀ , that is, the passed Therefore, in this step, the source node A determines the number of node hops passed by each route response according to the path information carried in each route response, and assigns the route response corresponding to the route with the least node hops The route is determined as the optimal route for this voice service.

For another example, the service type of this service is a video service type, and the formula corresponding to the video service type is W ₁ =a·Min_Bw+β·PDR, and its routing strategy is to select the path with the largest value of W ₁ , that is, select the path with the best Therefore, in this step, for each routing response, source node A obtains the current Min_Bw value and the value of PDR from the path information carried in the routing response, and Calculate the value of W ₁ corresponding to the route response through the calculation formula W _j =α·Min_Bw+β·PDR, then compare the size of the W ₁ value corresponding to each route response, and calculate the value of W ₁ corresponding to the route response with the largest value The route is determined as the optimal route for this voice service.

For another example, the service type of this service is the best-effort service type, and the formula corresponding to the best-effort service type is W ₂ γ·Max_Load+λ·Min_Bw+v·PDR, and its routing strategy is to select the one with the largest value of W ₂ Path, that is, to select the path that can best satisfy the minimum link bandwidth, maximum delivery rate and maximum load. Therefore, in this step, for each route response, source node A obtains from the path information carried in the route response The current Min_Bw value, the value of PDR and the value of Max_Load, and calculate the value of W ₂ corresponding to the route response by calculating the formula W ₂ =γ·Max_Load+λ·Min_Bw+v·PDR, and then compare each route Responding to the size of the corresponding W ₂ value, determining the route corresponding to the route response with the largest W ₂ value as the optimal route for the voice service.

Step 215: The source node A sends the current service data to the destination node C through the determined optimal route.

It should be noted that, in order to achieve better coupling between the routing scheme and the link layer, the present invention can be implemented on the second layer, ie, the link layer. In this way, the two-layer routing scheme of the present invention can make full use of link layer state parameters, such as network performance parameters such as remaining bandwidth, delivery rate and network load required when determining an optimal route corresponding to a service type, so that The routing protocol corresponding to the present invention is more sensitive to the network state, thus making the present invention easier to implement.

In a word, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (19)

1. A method for determining routing in a wireless mesh network, characterized in that the method comprises: setting different routing decision-making strategies for different business types; after the source node receives multiple routing responses carrying path information, according to The route decision policy corresponding to the current service type and the path information carried in each route response determine the route corresponding to the current service. 2. The method according to claim 1, further comprising: before the source node receives multiple routing responses carrying path information: A. After each intermediate node receives the routing request sent by the source node through broadcast, it updates the path information in the routing request according to the path information collected by the node; B. Each intermediate node sends the current routing request to the destination node respectively; C. After the destination node receives each routing request, it updates the path information in the routing request according to the path information collected by the node, and then carries the path information carried in each routing request in each routing response and sends it to source node. 3. The method according to claim 2, further comprising: between step A and step B: each intermediate node judges whether it has received the routing request sent by the source node to the destination node, if yes , then judge whether the packet sequence number of the routing request received is equal to the packet sequence number of the currently received routing request, if yes, then judge whether the path of the routing request currently received is better than the routing request ever received If the path is better, execute step B, if not, end the current process. 4. The method according to claim 3, characterized in that, the type of this service is voice; The judging whether the path of the currently received routing request is better than the previously received path of the routing request includes: judging whether the number of node hops from the source node to the intermediate node in the currently received routing request is less than that of the previously received routing request The number of node hops from the source node to the intermediate node in the received routing request, if yes, then determine that the path of the currently received routing request is better than the path of the previously received routing request, otherwise, determine The path of the currently received routing request is no better than the path of the previously received routing request. 5. The method according to claim 3, characterized in that, the type of this service is video; In step A, the step of updating the path information in the routing request according to the path information collected by this node includes: combining the remaining bandwidth information Bw _i from the previous hop node to the intermediate node with the information carried in the currently received routing request After taking the minimum value of the original Min_Bw, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the intermediate node with the currently received After the original PDR carried in the routing request is multiplied, use the multiplied result to update the value of the PDR in the currently received routing request, Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _N-1 ), the updated $\mathrm{PDR}=\underset{i=1}{\overset{i=N-1}{\mathrm{\Π}}}{\mathrm{pdr}}_{i,i+1},$ And N is the number of nodes from the source node to the intermediate node in the path, Bw _i is the statistical residual bandwidth of the i-th node from the source node to the intermediate node, pdr _{i, i+1} is from the source node to the The delivery rate from the i-th node to the i+1-th node among the intermediate nodes; The judging whether the path of the currently received routing request is better than the path of the previously received routing request includes: 100. The intermediate node respectively obtains the value of Min_Bw and the value of PDR from the currently received routing request and the previously received routing request, and uses the formula W ₁ =α·Min_Bw+β·PDR to calculate the The currently received routing request and the _W value of the previously received routing request, where α and β are weighting factors; 101. The intermediate node judges whether the W ₁ value of the currently received routing request is greater than the W ₁ value of the previously received routing request, and if so, determines that the route of the currently received routing request is better than that of the previously received routing request. Otherwise, determine that the path of the currently received routing request is not better than the path of the previously received routing request. 6. The method according to claim 3, characterized in that, the type of this service is best effort; In step A, the step of updating the path information in the routing request according to the path information collected by this node includes: combining the remaining bandwidth information Bw _i from the previous hop node to the intermediate node with the information carried in the currently received routing request After taking the minimum value of the original Min_Bw, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the intermediate node with the currently received After the original PDR carried in the routing request is multiplied, the result obtained after the multiplication is used to update the value of the PDR in the currently received routing request, and the load information Load _i of the intermediate node is carried in the currently received routing request. After taking the maximum value of the original Max_Load, use the maximum value to update the value of Max_Load in the currently received routing request, wherein, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,... Bw _N-1 ), the updated $\mathrm{PDR}=\underset{i=1}{\overset{i=N-1}{\mathrm{\Π}}}{\mathrm{pdr}}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _N ), and N is the number of nodes from the source node to the intermediate node in the path, and Bw _i is from Statistical remaining bandwidth from the source node to the i-th node in the intermediate nodes, pdr _{i, i+1} is the delivery rate from the source node to the i-th node in the intermediate nodes to the i+1-th node, Load _i is the load from the source node to the i-th node in the intermediate node; The judging whether the path of the currently received routing request is better than the path of the previously received routing request includes: 110. The intermediate node respectively obtains Max_Load, Min_Bw and PDR from the currently received routing request and the previously received routing request, and uses the formula W ₂ =γ·Max_Load+λ·Min_Bw+ν·PDR to calculate respectively Get the W ₂ value for the routing request that is currently received and the routing request that has been received, where γ, λ and ν are weighting factors; 111. The intermediate node judges whether the W ₂ value of the currently received routing request is greater than the W ₂ value of the previously received routing request, and if so, determines that the route of the currently received routing request is better than the previously received routing request. The path of the received routing request, otherwise, determine that the currently received path of the routing request is not better than the path of the previously received routing request. 7. The method according to claim 3, characterized in that, after each intermediate node judges that the path of the currently received routing request is better than the path of the previously received routing request, and after performing step B Before, it further includes: each intermediate node respectively judges whether its current resource status allows forwarding, if yes, execute step B, otherwise, end the current process. 8. The method according to claim 3, characterized in that, after each intermediate node judges that the path of the currently received routing request is better than the path of the previously received routing request, step B is executed Before, it further includes: each intermediate node respectively judges whether its own queue length is greater than a preset length threshold, if yes, ends the current process, otherwise executes step B. 9. The method according to claim 3, characterized in that, after each intermediate node judges that the path of the currently received routing request is better than the path of the previously received routing request, step B is executed Before, it further includes: each intermediate node respectively judges whether the currently received routing request has expired according to the life cycle carried in the currently received routing request, if yes, ends the current process, otherwise executes step B. 10. The method according to claim 3, characterized in that, after each intermediate node judges that the path of the routing request currently received is better than the path of the previously received routing request, and after performing step B Before, it further includes: each intermediate node searches its own route cache respectively, and judges whether there is a path from itself to the destination node in the route cache, if not, then directly executes step B, and if it exists, then judges the route cache Whether the path from itself to the destination node is better than the path carried in the currently received routing request, if so, each intermediate node will use the path information from itself to the destination node in the routing cache and all After the path information is integrated, it is carried in each routing response and sent to the source node, otherwise, step B is directly performed. 11. The method according to claim 2, further comprising: setting a routing criterion structure for storing path performance information in the TARP packet header of the routing request; The step of carrying the path information in the routing request includes: integrating the path information collected by this node with the existing path information in the currently received routing request and carrying it in the TARP packet header of the currently received routing request In the routing criterion structure. 12. The method according to any one of claims 2 to 11, characterized in that, setting different routing decision-making strategies for different service types comprises: for voice service types, setting the corresponding routing decision-making strategies as selecting nodes The route with the least number of hops; for the video service type, set the corresponding routing decision strategy to select the route with excellent delivery rate and remaining bandwidth; for the best-effort service type, set the corresponding routing decision strategy to select the node with a small load and The route with larger residual bandwidth and better delivery rate. 13. The method according to claim 12, characterized in that, the type of this service is voice; The step of determining the route corresponding to this service includes: the source node selects the route with the least node hops corresponding to the voice of this service type, and the node hop information carried in the response of each route, and selects the corresponding least node The route response of the hop count, and the address information of each node carried in the selected route response is determined as the route corresponding to this service. 14. The method according to claim 12, characterized in that, the type of this service is video; The step of updating the path information in the routing request according to the path information collected by the node includes: after the remaining bandwidth information Bw _i from the last hop node to the node and the original Min_Bw in the currently received routing request get the minimum value, use The minimum value updates the Min_Bw value in the currently received routing request, and after multiplying the delivery rate information pdr _{i, i+1} from the previous hop node to the current node by the original PDR carried in the currently received routing request, Update the value of the PDR in the currently received routing request with the result of the multiplication, Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _n-1 ), the updated $\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}{\mathrm{pdr}}_{i,i+1},$ And n is the number of nodes from the source node to the node in the path, _Bwi is the statistical residual bandwidth from the source node to the i-th node in the node, and pdr _{i, i+1} is from the source node to the node. The delivery rate from the i-th node to the i+1-th node in the current node; The step of determining the route corresponding to this service includes: the source node selects a route with an excellent delivery rate and remaining bandwidth according to the video corresponding to this service type, and the minimum remaining bandwidth information Min_BW and The delivery rate information PDR selects a route response corresponding to both the delivery rate and the minimum remaining bandwidth, and determines the address information of each node carried in the selected route response as the route corresponding to this service. 15. The method according to claim 14, wherein the step of selecting a route response corresponding to an excellent delivery rate and a minimum remaining bandwidth comprises: the source node obtains path minimum remaining bandwidth information Min_Bw from each route response respectively and path delivery rate information PDR, use the formula W ₁ = α·Min_Bw+β·PDR to calculate the W ₁ value for each route response, where α and β are weighting factors, and select the maximum W ₁ value corresponding to routing response. 16. The method according to claim 12, characterized in that the service type of this time is best effort; The step of updating the path information in the routing request according to the path information collected by this node includes: taking the minimum value of the remaining bandwidth information Bw _i from the last hop node to the current node and the original Min_Bw carried in the currently received routing request Afterwards, use the minimum value to update the Min_Bw value in the currently received routing request, and compare the delivery rate information pdr _{i, i+1} from the previous hop node to the current node with the original PDR carried in the currently received routing request After multiplication, use the multiplied result to update the value of the PDR in the currently received routing request, and after taking the maximum value of the load information Load _i of this node and the original Max_Load carried in the currently received routing request, use the The maximum value updates the value of Max_Load in the currently received routing request, Among them, the updated Min_Bw=min(Bw ₁ , Bw ₂ ,...Bw _i ,...Bw _n-1 ), the updated $\mathrm{PDR}=\underset{i=1}{\overset{i=\mathrm{no}-1}{\mathrm{\Π}}}{\mathrm{pdr}}_{i,i+1},$ Updated Max_Load=max(Load ₁ , Load ₂ , ..., Load _i , ..., Load _n ), and n is the number of nodes from the source node to the current node in the path, and Bw _i is from Statistical remaining bandwidth from the source node to the i-th node in the local node, pdr _{i, i+1} is the delivery rate from the source node to the i-th node in the local node to the i+1-th node, Load _i is the load from the source node to the i-th node in the said node; The step of determining the route corresponding to this service includes: the source node chooses the route corresponding to the best effort of the service type according to the current service type, which has a smaller node load and has a larger remaining bandwidth and a better delivery rate, and each route responds The minimum remaining bandwidth information Min_Bw, the maximum load information Max_Load, and the delivery rate information PDR of the path respectively carried in , select the route response with a relatively small load of the corresponding node and have a large remaining bandwidth and a better delivery rate, and respond to the selected route The address information of each node carried in , is determined as the route corresponding to this service. 17. The method according to claim 16, wherein the step of selecting a routing response corresponding to a node with a relatively small load, a large remaining bandwidth, and a better delivery rate comprises: the source node separately selects the routing response from each routing response Obtain the minimum remaining bandwidth information Min_Bw, maximum load information Max_Load, and path delivery rate information PDR, and use the formula W ₂ =γ·Max_Load+λ·Min_Bw+ν·PDR to calculate the W ₂ value for each route response, where , γ, λ, and ν are weighting factors, and select the routing response corresponding to the maximum W ₂ value.

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