Competition mechanism-fused controlled interception area width determination method

Abstract

The invention provides a method for determining the width of a controlled interception area fused with a competition mechanism, and belongs to the field of wireless ad hoc networks. In the competition stage, priority parameters are added, and broadcast requirements of part of nodes are competed and solved in a random number comparison mode; in a controlled interception area establishment stage, N can be increased when important information is transmitted preferentially or in large-hop-count transmission by utilizing a control message mechanism in combination with transmission hops and priority parameters, so that more cooperative communication nodes are introduced, and when small-hop-count transmission is carried out, the situation that excessive nodes are occupied and the network user capacity is influenced can be avoided through proper N; in addition, when the establishment of the controlled interception area fails, N can be dynamically adjusted to reestablish the connection. The method for confirming the width of the controlled interception area is optimized, a competition mechanism is fused, the problem of sudden network congestion is solved, N can be dynamically adjusted according to the actual situation so as to meet different information transmission requirements, and QoS guarantee of the relay blocking network is improved.

Description

Technical Field

[0001] The invention relates to the field of wireless ad hoc networks, and in particular to a method for determining a controlled interception area width integrating a competition mechanism. Background Art

[0002] In harsh communication environments, large-scale mobile self-organizing networks need to be able to support multiple communication links to establish communications simultaneously. However, the harsh communication channel environment and the frequent changes in network topology caused by network resource limitations and strong node mobility will have a serious impact on the overall network performance. The relay network is a mobile self-organizing network based on autonomous collaborative routing, which can significantly reduce the end-to-end delay in long-distance multi-hop transmission scenarios to a certain extent.

[0003] Mobile ad hoc networks are built based on autonomous cooperative communication between nodes and TDMA time slot allocation technology. Its nodes dynamically update their transmission time slots through the time slot allocation algorithm, which can coordinate the sending relationship between nodes and avoid channel conflicts. However, this technology cannot effectively solve the contradiction that the number of nodes that require broadcasting is greater than the number of multicast nodes supported by the network. To this end, the relay network establishes a controlled interception area based on the blocking function of the buffer node. In this area, a complete communication link can be carried out by broadcasting, thereby weakening the concept of routing. For the controlled interception area, its width N = 0 means that the area only contains the shortest path, and N ≠ 0 means that multiple cooperative communication nodes are added to increase the diversity gain of the communication link. However, how to reasonably determine the width of the controlled interception area to meet different service quality requirements is still a problem that needs to be studied. To address this problem, the following work exists in the existing technology:

[0004] First, by optimizing the selection method of the Buffer node in the blocking relay network and combining different application requirements and scenarios, the confirmation process of different identity nodes in the controlled interception area can be simplified to a certain extent. However, the actual application effect of this solution is not obvious.

[0005] Second, by periodically dividing the communication process of the entire relay network into the contention process, the time slot allocation process, and the data transmission process, the communication stage is periodicized, which can to a certain extent resist the degradation of network performance caused by frequent changes in network topology, but it cannot solve the problem of enriching and optimizing network QoS. Summary of the invention

[0006] In view of this, the present invention proposes a method for determining the width of a controlled interception area integrating a competition mechanism. The present invention is simple and easy to implement, takes into account the two factors of the shortest communication link hop count and information priority, and can effectively solve the network congestion problem that may occur in a relay network.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for determining the width of a controlled interception area integrating a competition mechanism is proposed. All nodes in the network enter the competition phase according to the same broadcast cycle. In the competition phase, each node first initializes its priority parameter to 0. Then, the node v with broadcast requirements i Perform the following steps:

[0009] S1, initialize the competition parameter α(v i )=1, generate random competition number γ(v i )∈[0,α(v i )];

[0010] S2, adjust the priority parameter Priority (v i ), for common information, the priority parameter remains unchanged, for important information, Priority(v i )=Priority(v i )+1;

[0011] S3, broadcasts the contention message in a flooding manner, and the contention message contains a random contention number γ(v i ) and the priority parameter Priority(v i );

[0012] S4, continue to receive contention messages, read the random contention number and priority parameter in the message, if the priority parameter in a certain message received is greater than the priority parameter of this node, the node fails in the competition, saves the priority parameter in the message received this time, and no longer forwards the contention message; if after the contention phase expires, the priority parameters in the received messages are all equal to the priority parameter of this node, then compare the random contention number of this node with the random contention number in the received message one by one, if the random contention number in the received message is greater than the random contention number of this node, the node fails in the competition;

[0013] If the node does not meet the competition failure condition after the competition phase expires, the node will succeed in the competition and become the node that obtains the broadcast permission in this broadcast cycle. s , update the competition parameter α(v s )=1-γ(v s ); At this point, all nodes have obtained node v s The priority parameter Priority(v s );

[0014] After the competition phase is over, the controlled interception area establishment phase begins. The node v that obtains the broadcast permission sSend RTS control message in flooding mode, then each node v j Perform the following steps:

[0015] S5, continue to receive RTS control messages, read the current node and the source node v s If the current node is not the destination node of the RTS control message, the RTS control message is forwarded; if the current node is the destination node of the RTS control message, the RTS control message is forwarded. D , then determine the source node v s With the destination node v D The shortest hop number δ between them is calculated based on δ and node v s The priority parameter Priority(v s ), determine the width N of the controlled interception area, add N and δ to the CTS control message, and then send the CTS control message to v in a flooding manner s ;

[0016] S6, receive the CTS control message, read the shortest hop count δ and the width of the controlled interception area N, if d(v s , v j )+d(v D , v j-1 )+1>δ+N, then determine node v j-1 is a blocking node, otherwise, determine node v j is a relay node to establish a controlled interception area, where v j For this node, v j-1 is the previous hop node of this node, and d() represents the number of hops between two nodes;

[0017] When the source node v s When the CTS control message is received, the CTS control message is sent and received, and the source node v s Start data transmission and send information data packets;

[0018] If the destination node v D The source node v is not received within the waiting time s The destination node v D Adjust the width N of the controlled interception area, resend the CTS packet, and wait again.

[0019] Furthermore, in step S5, the width N of the controlled interception area is determined as follows:

[0020] When δ<0.5x and Priority(v s )=0, N=0;

[0021] When 0.5x<δ<x and Priority(v s)=0, N=1;

[0022] When x<δ or Priority(v s )≠0, N=2;

[0023] Wherein, x is the decision parameter, x=0.01X, and X is the total number of nodes in the network.

[0024] Furthermore, in step S5, the destination node v D Send the CTS control message to v in a flooding manner s , is sent after t time has passed after receiving the RTS control message, where t≥max(1,N), and max() represents a larger value.

[0025] Furthermore, the width N of the controlled interception area is adjusted in a manner of N=N+1.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention uses a competition mechanism to add information priority content to the competition message, distinguish important information, and enable nodes that transmit important messages to be preferentially elected as broadcast nodes in this cycle, thereby realizing priority forwarding of important information, thereby avoiding serious information congestion to a certain extent, ensuring network robustness, and solving the problem of network congestion caused by the number of nodes with broadcast requirements being greater than the number of multicasts that the network can simultaneously support in a single cycle in the current relay network architecture.

[0028] (2) The present invention uses the two factors of the number of hops between the source and destination nodes and the importance of the information to determine the width of the controlled interception area. When a large number of hops is used to transmit messages or important messages, the number of nodes participating in the cooperative communication is increased, and the diversity gain is improved, thereby achieving priority forwarding of important information, competitive forwarding of information at the same level, and accurate forwarding of long-distance and large-hop communication links, solving the problems of disconnection and mistransmission that may exist in large-hop transmission, and enhancing the robustness of the communication link.

[0029] (3) The present invention realizes competitive broadcasting of information of the same level through a disconnection retransmission mechanism and provides retransmission guarantee.

[0030] (4) The present invention realizes the setting of the controlled interception area width, protection time t and decision parameter x in combination with the actual scale of the network, and can dynamically adapt to networks of various scales.

[0031] In summary, the prior art usually only sets a fixed setting for the width of the controlled interception area, and does not associate the width with the actual transmission requirements and the quality of network services. The present invention solves the network congestion problem that may occur in the relay network by incorporating a competition mechanism; by competing for broadcast nodes, and combining the two parameters of the shortest communication link hop count and information priority, a setting rule for the width of the controlled interception area is proposed. The application of this rule can achieve priority forwarding of important information, competitive forwarding of the same information level, and accurate forwarding of long-distance and large-hop communication links. In addition, the setting of the decision parameters of the present invention is related to the network scale, which increases the compatibility of network applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further elaborated below.

[0034] A method for determining the width of a controlled interception area integrating a competition mechanism is applied to a relay network consisting of X nodes. Figure 1 The flowchart of this method is shown in Figure 2. This method sets the same broadcast cycle for each node and divides the broadcast cycle into three stages: competition, establishment of a controlled interception area, and data transmission. In the competition stage, each node first initializes the priority parameter to 0, and then the node v with broadcast demand i Perform the following steps:

[0035] S1, node v i Initialize the competition parameter α(v i )=1, generating a random competition number γ(v i )∈[0,α(v i )];

[0036] S2, node v i Adjust the priority parameter Priority(v) according to the content of the information to be sent. i ), for common information, the priority parameter remains unchanged, for important information, Priority(v i )=Priority(v i )+1;

[0037] S3, Node v i The contention message is broadcasted in a flooding manner. The content of the contention message is shown in Table 1:

[0038] Table 1 Contents of competition message

[0039]

[0040] S4, node vi Continue to receive contention messages, read the random contention number and priority parameter in the message, if the priority parameter in a certain message received is greater than the priority parameter of this node, the node fails in the competition, saves the priority parameter in the message received this time, and no longer forwards the contention message; if after the contention phase expires, the priority parameters in the received messages are all equal to the priority parameters of this node, then compare the random contention number of this node with the random contention number in the received message one by one, if the random contention number in the received message is greater than the random contention number of this node, the node fails in the competition;

[0041] If the node does not meet the competition failure condition after the competition phase expires, the node succeeds in the competition and becomes the broadcast node v s , obtain the broadcast permission within this broadcast cycle, and update the competition parameter α(v s )=1-γ(v s ); At this point, all nodes have obtained node v s The priority parameter Priority(v s );

[0042] After the competition phase is over, the controlled interception area establishment phase is entered to obtain the broadcast node v s Send RTS control messages in flood mode (v s is the source node), then each node v j Perform the following steps:

[0043] S5, node v j Continue to receive RTS control messages and read the current node and source node v s If the current node is not the destination node of the RTS control message, the RTS control message is forwarded. The content of the RTS control message is shown in Table 2:

[0044] Table 2 RTS message content

[0045]

[0046] If this node is the destination node of the RTS control message v D , then determine the source node v s With the destination node v D The shortest hop number δ between them is used to determine the width N of the controlled interception area based on δ and the priority parameter of this node:

[0047] When δ<0.5x and Priority(v s )=0, N=0;

[0048] When 0.5x<δ<x and Priority(v s )=0, N=1;

[0049] When x<δ or Priority(v s )≠0, N=2;

[0050] The decision parameter x is determined by the network scale X, and it is stipulated that x / X=0.01, that is, x=0.01X.

[0051] Then, node v D Add N and δ to the CTS control message, set the protection time t≥max(1, N), and send the CTS control message to v in a flooding manner after t time from the receipt of the RTS control message s ; The content of the CTS control message is shown in Table 3:

[0052] Table 3 CTS message content

[0053]

[0054] S6, node v j Receive the CTS control message, read the shortest hop count δ and the width of the controlled interception area N, if d(v s , v j )+d(v D , v j-1 )+1>δ+N, then determine node v j-1 is a blocking node, otherwise, determine node v j is a relay node to establish a controlled interception area, where v j For this node, v j-1 is the previous hop node of this node, d9) represents the number of hops between two nodes;

[0055] When the source node v s When the CTS control message is received, the CTS control message is sent and received, the controlled interception area establishment phase is completed, and the data transmission phase begins. Node v s Start sending information data packets;

[0056] This method also has a disconnection retransmission mechanism, that is, if the destination node v D The source node v is not received within the waiting time s The destination node v D Adjust the width of the controlled interception area N=N+1, resend the CTS data packet, and wait again.

[0057] After a broadcast cycle, all nodes enter the contention phase again, re-establish the controlled interception area and send data.

[0058] In the competition stage, the present invention increases the priority parameter and uses the random number comparison method to compete and solve the broadcasting needs of some nodes; in the controlled interception area establishment stage, the control message mechanism is used, combined with the transmission hop number and priority parameter, so that when important information is transmitted first or a large number of hops are transmitted, the width N of the controlled interception area can be increased, thereby introducing more cooperative communication nodes and improving link diversity gain. When the number of hops is small, the appropriate N can be used to avoid occupying too many nodes and affecting the network user capacity; in addition, when the controlled interception area fails to be established, the present invention can also dynamically adjust N to re-establish the connection. The present invention optimizes the confirmation method of the width of the controlled interception area, integrates the competition mechanism, solves the problem of sudden network congestion, can dynamically adjust N according to actual conditions to meet different information transmission needs, and improves the QoS guarantee of the relay network.

Claims

1. A method for determining the width of a controlled interception area integrating a competition mechanism, characterized in that: All nodes in the network enter the competition phase according to the same broadcast cycle. In the competition phase, each node first initializes its priority parameter to 0, and then the node v with broadcast requirements i Perform the following steps: S1, initialize the competition parameter α(v i )=1, generating a random competition number γ(v i )∈[0,α(v i )]; S2, adjust the priority parameter Priority (v i ), for common information, the priority parameter remains unchanged, for important information, Priority(v i )=Priority(v i )+1; S3, broadcasts the contention message in a flooding manner, and the contention message contains a random contention number γ(v i ) and the priority parameter Priority(v i ); S4, continue to receive contention messages, read the random contention number and priority parameter in the message, if the priority parameter in a message received at a certain time is greater than the priority parameter of this node, the node fails in the competition, saves the priority parameter in the message received at that time, and no longer forwards the contention message; If the priority parameters in the received messages are equal to the priority parameters of this node after the contention phase expires, the random contention number of this node is compared with the random contention number in the received messages. If the random contention number in the received messages is greater than the random contention number of this node, the node fails in the contention. If the node does not meet the competition failure condition after the competition phase expires, the node will succeed in the competition and become the node that obtains the broadcast permission in this broadcast cycle. s , update the competition parameter α(v s )=1-γ(v s ); At this point, all nodes have obtained node v s The priority parameter Priority(v s ); After the competition phase is over, the controlled interception area establishment phase begins. The node v that obtains the broadcast permission s Send RTS control message in flooding mode, then each node v j Perform the following steps: S5, continue to receive RTS control messages, read the current node and the source node v s If the current node is not the destination node of the RTS control message, the RTS control message is forwarded; if the current node is the destination node of the RTS control message, the RTS control message is forwarded. D , then determine the source node v s With the destination node v D The shortest hop number δ between them is calculated based on δ and node v s The priority parameter Priority(v s ), determine the width N of the controlled interception area, add N and δ to the CTS control message, and then send the CTS control message to v in a flooding manner s ; S6, receive the CTS control message, read the shortest hop count δ and the width of the controlled interception area N, if d(v s , v j )+d(v D , v j-1 )+1>δ+N, then determine node v j-1 is a blocking node, otherwise, determine node v j is a relay node to establish a controlled interception area, where v j For this node, v j-1 is the previous hop node of this node, and d() represents the number of hops between two nodes; When the source node v s When the CTS control message is received, the CTS control message is sent and received, and the source node v s Start data transmission and send information data packets; If the destination node v D The source node v is not received within the waiting time s The destination node v D Adjust the width N of the controlled interception area, resend the CTS packet, and wait again.

2. According to the method for determining the width of a controlled interception area integrating a competition mechanism according to claim 1, it is characterized in that: In step S5, the width N of the controlled interception area is determined as follows: When δ<0.5x and Priority(v s )=0, N=0; When 0.5x < δ < x and Priority(v s ) = 0, N = 1; When x<δ or Priority(v s )≠0, N=2; Wherein, x is the decision parameter, x=0.01X, and X is the total number of nodes in the network.

3. The method for determining the width of a controlled interception area integrating a competition mechanism according to claim 1, characterized in that: In step S5, the destination node v D Send the CTS control message to v in a flooding manner s , is sent after t time has passed after receiving the RTS control message, where t≥max(1,N), and max() represents a larger value.

4. The method for determining the width of a controlled interception area integrating a competition mechanism according to claim 1, characterized in that: The controlled interception area width N is adjusted in a manner of N=N+1.

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