A fast networking method for MANET based on OLSR routing protocol

Abstract

The present invention provides a MANET fast networking method based on the OLSR routing protocol. The method is applied to each node of a wireless self-organizing network, adopts a step-by-step variable transmission cycle, and adopts different routing message transmission cycles in the node startup phase, transition phase, and stable phase. The present invention uses a step-by-step variable transmission cycle to shorten the transmission cycle in the node access phase, speed up the broadcast of the topological information of the node and neighboring nodes in the entire network, thereby speeding up the networking speed; when the network is relatively stable, a conventional routing message transmission cycle is adopted to avoid network congestion, thereby speeding up the access speed while not causing a sudden increase in routing overhead in a steady-state scenario.

Description

Technical Field

[0001] The invention relates to a wireless communication method, in particular to a wireless ad hoc network fast networking method based on OLSR routing. Background Art

[0002] A wireless ad hoc network (MANET) is a decentralized, self-organizing wireless network in which each node is independent and mutually discoverable. Considering the mobility of nodes in a wireless ad hoc network, in order to update network routes in a timely manner, the OLSR (Optimized Link State Routing, OLSR) routing protocol can be used in a wireless ad hoc network. The OLSR routing protocol uses a multi-point relay node mechanism (Multi Point Relay, MPR) to optimize the flooding algorithm and reduce network overhead.

[0003] In order to obtain the routing information and topology information of the entire network, the OLSR routing protocol requires each node to periodically send OLSR control messages, including HELLO messages and TC messages. By periodically sending HELLO messages, the link status of adjacent nodes can be obtained. By periodically sending TC messages, the topological relationship of nodes in the entire network can be obtained. Through the above process, nodes can obtain the routing information and topology information of the entire network, thereby achieving the purpose of networking at the routing level.

[0004] The OLSR routing protocol stipulates that, under normal circumstances, the sending cycle of HELLO messages and TC messages is a fixed cycle. Even if the event-triggered generation of HELLO messages and TC messages is adopted, the shortest sending cycle constraint must be met. During the networking phase, nodes need to go through multiple OLSR routing control message sending cycles to obtain the routing and topology information of the entire network, which is a relatively slow process. Shortening the sending cycle of OLSR routing control messages is conducive to speeding up the process, but it will cause the network to broadcast more OLSR control messages in a short period of time, resulting in a sudden increase in network overhead.

[0005] In short, in wireless ad hoc networks, air interface resources are very valuable. If the HELLO message and TC message sending cycle is too short, the network will broadcast more OLSR control messages, increase network overhead, and cause network congestion. If the HELLO message and TC message sending cycle is too long, it will lead to problems such as slow boot-up speed and untimely response to network topology changes. Therefore, the node access speed and network overhead are a pair of contradictions. Summary of the invention

[0006] In view of this, the present invention provides a MANET fast networking method based on the OLSR routing protocol, which can accelerate the network access speed and will not cause a sudden increase in routing overhead in a steady-state scenario.

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

[0008] A MANET fast networking method based on OLSR routing protocol is applied to each node of wireless self-organizing network, adopts step-type variable sending cycle, and adopts different routing message sending cycles in the startup stage, transition stage and stable stage of the node.

[0009] Furthermore, in the startup phase, the period for the node to send HELLO messages is set to mT1, and the period for the node to send TC messages is set to mT2, 0 < m < 1; T1 is the sending interval of the HELLO message specified in the OLSR routing protocol, and T2 is the sending interval of the TC message specified in the OLSR routing protocol.

[0010] Furthermore, when the number of HELLO messages and TC messages sent by the node reaches the threshold Thread1, 5 < Thread1 <20, the node enters the transition stage from startup to stability. At this time, the period of sending HELLO messages by the node is set to nT1, and the period of sending TC messages by the node is set to nT2, 0 < n < 1, and n > m.

[0011] Further, when the number of HELLO messages and TC messages sent by the node reaches the threshold Thread2, 20 < Thread2 <35, the node enters the stable stage, and the sending intervals of the HELLO messages and TC messages are restored to T1 and T2.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) Accelerate network access and respond promptly:

[0014] The OLSR routing protocol is often used in wireless self-organizing networks due to its strong adaptability. Each node in a wireless self-organizing network is powered on to form a network by itself, and the speed of powering on and forming the network directly affects the normal use of the node functions. This method can speed up the node access speed, obtain the routing information and topology information of the entire network in a shorter time, and respond to user needs in a timely manner.

[0015] (2) Reduce routing message overhead and improve robustness:

[0016] The OLSR routing protocol periodically sends HELLO messages and TC messages. If the sending period is too short, the network will have a large amount of routing information in a short period of time, causing network congestion. This method reduces the frequency of routing message sending after the networking stage is over, which can effectively reduce network overhead and improve network robustness.

[0017] (3) Reduce preemption of air interface resources and improve user experience:

[0018] The air interface messages of OLSR belong to control signaling. Reducing the network overhead occupied by control signaling can reduce the preemption of air interface resources, effectively improve the efficiency of data transmission, and enhance the user experience.

[0019] In summary, the present invention uses a stepped variable transmission period. During the node network access stage, the transmission period is shortened to accelerate the broadcast of the topological information of this node and adjacent nodes throughout the network, thereby accelerating the network formation speed. When the network is relatively stable, a conventional routing message transmission period is adopted to avoid network congestion, so that while accelerating the network access speed, it will not cause a sudden increase in routing overhead in the steady state scenario. Brief Description of the Drawings

[0020] Figure 1 It is a schematic diagram of a stepped variable transmission period. Detailed Embodiment

[0021] The technical solutions and effects of the present invention will be further described in detail below.

[0022] According to the OLSR routing protocol, the transmission interval of HELLO messages is T1, and the transmission interval of TC messages is T2. Usually, T1 < T2 because HELLO messages are only transmitted between adjacent nodes and cannot be forwarded. While TC messages can be forwarded. To avoid the impact of flooding routing messages on the network, the protocol restricts the generation and forwarding of TC messages too frequently. This method uses a stepped variable transmission period and refers to the schematic diagram Figure 1 to adopt different routing message transmission periods in the startup stage, transition stage, and stable stage, so as to achieve the purpose of accelerating the network formation speed in the startup stage and not causing a sudden increase in network overhead due to an increase in routing messages in the steady state.

[0023] Considering the need for rapid network formation during the node startup stage, in order to obtain the network routing and topological information in a timely manner, the transmission intervals of HELLO messages and TC messages are modified, and a scaling factor called m (0 < m < 1) is introduced. That is, during the startup stage, the period for the node to periodically send HELLO messages is mT1, and the period for the node to periodically send TC messages is mT2.

[0024] When the number of HELLO messages and TC messages sent by the node reaches the threshold Thread1, the transmission intervals of HELLO messages and TC messages are modified, and a scaling factor called n (0 < n < 1, and n > m) is introduced. That is, during the transition stage from startup to steady state, the period for the node to periodically send HELLO messages is nT1, and the period for the node to periodically send TC messages is nT2.

[0025] When the number of sent HELLO messages and TC messages reaches the threshold Thread2, the sending intervals of the HELLO messages and TC messages are restored to T1 and T2.

[0026] Here is a more specific example:

[0027] In a self-organizing network with a limited number of nodes, the HELLO message sending period T1=3 seconds, the TC message sending period T2=6 seconds, the scaling factor m=1 / 3, n=2 / 3, Thread1=15, Thread2=30.

[0028] When the node is powered on, the node's HELLO message sending cycle is mT1 = 1 second, and the TC message sending cycle is mT2 = 2 seconds. Each time the node sends a HELLO message or TC message, it needs to increase its respective sending counter by one.

[0029] When the HELLO message sending counter value is greater than 15, the HELLO message sending period is modified to nT1 = 2 seconds. When the TC message sending counter value is greater than 15, the TC message sending period is nT2 = 4 seconds.

[0030] When the HELLO message sending counter value is greater than 30, the HELLO message sending period is modified to nT1 = 3 seconds. When the TC message sending counter value is greater than 30, the TC message sending period is nT2 = 6 seconds.

Claims

1. A MANET fast networking method based on OLSR routing protocol, characterized in that: Applied to each node in a wireless ad hoc network, a stepped variable transmission period is adopted, and different routing message transmission periods are used in the startup phase, transition phase, and stable phase of the node; In the startup phase, the period for the node to send HELLO messages is set to mT1, and the period for the node to send TC messages is set to mT2, where 0 < m < 1; T1 is the transmission interval of HELLO messages specified in the OLSR routing protocol, and T2 is the transmission interval of TC messages specified in the OLSR routing protocol; When the number of HELLO messages and TC messages sent by the node reaches the threshold Thread1, where 5 < Thread1 < 20, the node enters the transition phase from startup to stability. At this time, the period for the node to send HELLO messages is set to nT1, and the period for the node to send TC messages is set to nT2, where 0 < n < 1 and n > m; When the number of HELLO messages and TC messages sent by the node reaches the threshold Thread2, where 20 < Thread2 < 35, the node enters the stable phase. At this time, the transmission intervals of HELLO messages and TC messages are restored to T1 and T2.

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