A routing method for aviation ad hoc networks based on end-to-end quality parameters

Abstract

The present invention claims protection for an aviation ad hoc network routing method based on end-to-end quality parameters, belonging to the field of aviation ad hoc networks. The method mainly integrates quality parameters such as path remaining time, path carrying capacity, path delay, and path load utilization, and through adaptive weight technology, all quality parameter index values ​​are weighted and summed, and the weighted result is used as the overall score of the path, and the path with the highest overall score is selected as the routing path from the aircraft node to the base station. A base station adaptive broadcast mechanism is designed, and the base station can dynamically adjust the range of the base station broadcast so that the base station can cover more source aircraft nodes. During the flight of the aircraft, it may be disconnected from the corresponding base station, resulting in communication interruption. A threshold mechanism and a self-inquiry mechanism are introduced to ensure that the aircraft node can perceive the changes in the link in time and make decisions in time.

Description

Technical Field

[0001] The invention belongs to the field of aviation ad hoc networks and is an aviation ad hoc network routing algorithm based on end-to-end quality parameters. Background Art

[0002] In recent years, with the continuous development of aviation, the aviation market has undergone tremendous changes, and people are increasingly interested in providing Internet access in the cabin. The cellular system provides direct communication between aircraft and ground stations, but it is easy to cause link interruption in areas where it is difficult to build base stations, such as deserts and oceans. In order to meet the communication needs of these areas, aircraft can realize communication between civil aircraft and ground base stations through satellite relay. Satellite-based space networks can provide a wide coverage area and high-speed data transmission, but satellite communications have the disadvantages of high cost, extended time, and difficult hardware upgrades. Aviation ad hoc networks can better meet the needs of future aviation communications. They can enable civil aircraft nodes to dynamically maintain communication between aircraft nodes and other aircraft nodes in a specific way without the deployment of ground infrastructure. Under this network topology, two aircraft that cannot communicate directly can use other aircraft node relays to forward packets, thereby realizing multi-hop communication. In places where it is difficult to build base stations, the idea of ​​multi-hop relay communication of aeronautical ad hoc networks can be used to integrate aeronautical ad hoc networks with ground base stations. As long as there is an aircraft node in the aeronautical ad hoc network within the coverage of the base station, other aircraft nodes that are not covered by the base station signal can use the aircraft node to establish a connection with the base station through multi-hop. The integration of aeronautical ad hoc networks and ground base stations can not only solve the defect that civil aircraft can only rely on expensive satellite relays to communicate with ground base stations in places where it is difficult to build base stations, but also propose a solution to the base station coverage problem for civil aircraft to access 5G networks in the future.

[0003] The existing civil aviation ad hoc network routing algorithms focus on the communication between aircraft nodes within the civil aviation ad hoc network. These routing algorithms have good performance for the communication between aircraft nodes. For example, an AANET joint routing algorithm based on geographic location information (CN201410460463.6) not only retains the efficiency and simplicity of the greedy forwarding strategy in the geographic routing protocol, but also combines with the reactive routing protocol to establish a more effective and stable routing path from aircraft node to aircraft node. However, this routing algorithm is aimed at the routing problem from aircraft node to aircraft node, and cannot be directly used to solve the path selection problem from aircraft node to base station. First, aircraft have multiple types of services, and only considering a single routing parameter is blind. This method selects multiple quality parameters, such as path remaining time, path carrying capacity, path delay, and path load utilization, which can not only ensure the selection of a stable path, but also ensure the load balance of each path, ensure that the path is not congested, and at the same time reduce the end-to-end delay from aircraft node to base station. Furthermore, if the TTL value is set too small, there may be more aircraft nodes in the passive area, and the aircraft nodes cannot receive the gateway notification message in real time, and cannot perceive the change of the link in real time, which may cause the aircraft nodes to choose a link with high latency or interruption, which may affect the passengers' Internet experience at best, and endanger the flight safety of civil aircraft at worst. If the TTL value is set too large, the gateway notification message will be flooded in a larger range, causing a large network overhead and network congestion. This method mainly adjusts the TTL value of the base station broadcast message in the next period of time according to the hop count information of the source aircraft node registered to the current gateway, so that the active area of ​​the gateway can cover as many source aircraft nodes registered to the current base station as possible.

[0004] At present, there is no aviation ad hoc network routing method based on end-to-end quality parameters. This method integrates quality parameters such as path remaining time, path carrying capacity, path delay, and path load utilization. Through adaptive weight technology, all indicator values ​​are weighted and summed, and the weighted result is used as the overall score of the path. The path with the highest overall score is selected as the routing path from the aircraft to the base station. A base station adaptive broadcast mechanism is designed, and the base station can dynamically adjust the range of the base station broadcast so that the base station can cover more source aircraft nodes. Summary of the invention

[0005] The present invention aims to solve the above problems of the prior art. A method for routing an aviation ad hoc network based on end-to-end quality parameters is proposed. The technical solution of the present invention is as follows:

[0006] An aviation ad hoc network routing method based on end-to-end quality parameters comprises the following steps:

[0007] The base station dynamically adjusts the broadcast range of the gateway announcement message according to the hop count information of the source aircraft node registered to the current base station, and broadcasts the gateway announcement message;

[0008] After receiving the gateway notification message, the aircraft node calculates the parameters including the remaining time of the aircraft node's path, path carrying capacity, path delay, and path load utilization, and compares the calculation results with the corresponding fields carried in the received gateway notification message. If the corresponding conditions are met, the corresponding fields in the gateway notification message are updated;

[0009] The aircraft node calculates the weight of each path through adaptive weighting technology according to the remaining path time, path load capacity, path delay, path load utilization and other parameters carried in the gateway announcement message. When the aircraft node needs to communicate with the ground base station, the aircraft node routing table entry is checked. If there are multiple routing table entries to the relevant base station in the routing table, the path with the largest weight value is selected as the routing path from the node to the base station; if there is no routing table entry information from the aircraft node to the base station, it means that the node is not within the broadcast range of the base station's announcement message, and the passive gateway discovery mechanism is started;

[0010] When the aircraft node does not receive the gateway notification message broadcast by the base station for a period of time, the aircraft node uses autonomous inquiry to perceive the link changes from the base station to the aircraft.

[0011] Furthermore, the broadcast range of the gateway announcement message is dynamically adjusted according to the following formula:

[0012]

[0013] Among them, TTL min It is the minimum broadcast range set by the base station, TTL max It is the maximum broadcast range set by the base station, TTL t+1 is the broadcast range of the base station in the next time period, TTL t is the broadcast range of the base station at the current moment, MAX_HOP t It is the maximum number of hops of each source aircraft node to which the base station sends the data packet in the tth time period. threshold represents the allowed hop count threshold.

[0014] Furthermore, the parameters including the path remaining time, path carrying capacity, path delay, and path load utilization of the aircraft node are calculated, specifically including:

[0015] (1) Calculation formula for remaining path time:

[0016] L i =min{L cj},j=1,2,...,n

[0017] Where n is the number of aircraft on path i, L cj represents the remaining connection time of the jth link among all the links on the path i from the aircraft node to the base station; assuming that the link formed by nodes m and k is a link on the path i from the node to the base station, the link remaining time L of the link formed by nodes m and k is c The calculation is as follows:

[0018]

[0019] Where (x m ,y m ) and (x n ,y n ) are the coordinates of nodes m and n, v m and v n is the velocity of node m and node n, θ m and θ n is the heading angle between node m and node n; R represents the communication radius of civil aircraft; where a = v m cosθ m -v n cosθ n , b = x m -x n , c = v m sinθ m -v n sinθ n , d = y m -y n .

[0020] (2) Path carrying capacity calculation formula:

[0021] C i =min{C j},j=1,2,...,n

[0022] Where n is the number of aircraft nodes on path i, C j Indicates the carrying capacity of the jth aircraft node on the current path i;

[0023] C j =C j_max -C j_cur -b

[0024]

[0025] Among them C j_max is the maximum carrying capacity of node j, C j_cur is the current load of node j, b is the protection load of the aircraft node, r irepresents the average packet arrival rate of data packets forwarded by node j from node i, k i represents the average packet size of the data packets forwarded by node j from node i;

[0026] (3) Path delay calculation formula:

[0027]

[0028] Where D node(j) represents the delay of the data packet on path i from the previous hop of aircraft node j to aircraft node j;

[0029] (4) Path load utilization calculation formula:

[0030] LU i =min{U j}, j = 1, 2, ..., n

[0031] U j represents the load utilization of node j on path i, C max is the total capacity of node j, C cur is the current load of node j.

[0032] Furthermore, the adaptive weighting technology calculates the weight value of each path, specifically including: firstly scaling the metric parameter, the metric scaling method of the positive criterion: Metric scaling for negative criteria: Where S ij represents the scaled value of parameter j in path i, M max Indicates the maximum value of the metric, M min Represents the minimum value in the metric; then calculate the final weight value of each path: Where S ij represents the scaled value of parameter j in path i, where w j is the weight factor of each parameter,

[0033] Furthermore, the aircraft node senses the link changes between the aircraft node and the base station by autonomous inquiry, specifically including: when the aircraft node does not receive the gateway announcement message broadcast by the base station after 4 cycles or before the path lifetime is about to expire, it broadcasts a gateway request message. If the aircraft node subsequently receives a gateway reply message from the base station or other aircraft nodes, the corresponding routing table information is updated; if the gateway reply message is not received within a period of time, the gateway request message is broadcast again. If the corresponding gateway reply message is not received twice in a row, it is considered that the current aircraft node is in an isolated state, and at this time it must maintain connection with the ground base station through satellite relay.

[0034] The advantages and beneficial effects of the present invention are as follows:

[0035] The present invention proposes an aviation ad hoc network routing algorithm based on end-to-end quality parameters. For the routing problem between aircraft nodes and base stations, it is necessary to ensure that a stable path is selected, and to ensure that the load of each path is balanced, to ensure that the path is not congested, and at the same time, to minimize the end-to-end delay from the aircraft node to the base station. The existing civil aviation ad hoc network routing algorithms focus on the communication between aircraft nodes within the civil aviation ad hoc network. These algorithms have limitations in the routing between aircraft and base stations, such as the quality parameters considered are too single, and the path information cannot be updated in real time, and the optimal link between the aircraft node and the base station cannot be selected. Furthermore, if the broadcast range of the base station is set too large, it will lead to excessive overhead and cause network congestion; if the broadcast range of the base station is set too small, the aircraft node will not be able to perceive the change of the path in real time, and the aircraft node may select a link with high delay or interruption, which will affect the passenger's Internet experience at the least, and endanger the flight safety of civil aircraft at the worst. Finally, due to the dynamic characteristics of the ad hoc network, the aircraft node will be disconnected, resulting in the aircraft node being unable to receive the gateway notification message broadcast by the base station, affecting the safety of civil aircraft.

[0036] Therefore, the aviation ad hoc network routing algorithm based on end-to-end quality parameters of the present invention becomes an effective method to solve these problems. It is specifically manifested in the following three points:

[0037] (1) The present invention discloses an aviation ad hoc network routing algorithm based on end-to-end quality parameters. The main feature is that it comprehensively considers multiple end-to-end quality parameters as measurement indicators for routing selection, thereby overcoming the shortcoming that a single quality parameter causes blindness in routing selection. It can ensure that the selected path lasts for a long time, the path load is balanced, and has a low end-to-end delay.

[0038] (2) The aviation ad hoc network routing algorithm based on end-to-end quality parameters described in the present invention mainly adopts a base station adaptive broadcast mechanism. The base station dynamically adjusts the broadcast range of the gateway announcement message according to the hop count information of the source aircraft node registered to the current base station, so that most civil aviation aircraft nodes registered to the current base station can perceive the changes in the routing path of the base station in real time and make routing decisions in time.

[0039] (3) The aviation ad hoc network routing algorithm based on end-to-end quality parameters described in the present invention has the main feature of using an autonomous inquiry method of aircraft nodes to ensure that disconnected aircraft nodes can perceive changes in link status in a timely manner, greatly increasing the security of civil aviation aircraft communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1It is a simplified flow chart of the routing algorithm of the preferred embodiment provided by the present invention;

[0041] Figure 2 A simplified flow chart of the base station adaptive broadcast mechanism provided by the present invention;

[0042] Figure 3 A flow chart of the autonomous inquiry mechanism provided by the present invention;

[0043] Figure 4 A flow chart of aircraft node maintenance quality parameters provided by the present invention. DETAILED DESCRIPTION

[0044] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention.

[0045] The technical solution of the present invention to solve the above technical problems is:

[0046] The purpose of the present invention is to provide an aviation ad hoc network routing algorithm based on end-to-end quality parameters, which is used for aircraft to base station routing path selection in an aviation ad hoc network environment. The base station broadcasts a variety of end-to-end quality parameters through an adaptive broadcast mechanism, and the aircraft node calculates the weight of each path through an adaptive weighting technology, and selects the path with the largest weight value as the routing path from the aircraft node to the base station. This technical solution is proposed.

[0047] like Figure 1 As shown, the following steps are included:

[0048] Step 1: The base station counts the hop count information of the source aircraft nodes registered to the current base station, dynamically adjusts the broadcast range of the gateway announcement message based on the statistical results, and broadcasts the gateway announcement message, mainly to enable most civil aviation aircraft nodes registered to the current base station to perceive the changes in the routing path to the base station in real time and make routing decisions in a timely manner. The specific base station adaptive broadcast mechanism is as follows: Figure 2 As shown:

[0049] First, the base station counts the maximum number of hops MAX_HOP of each source aircraft node sending data packets in the tth time period t ; Then set MAX_HOP t With TTL min and TTL max Compare; if MAX_HOP t Less than TTL min , then set the next broadcast range to TTL t -1 and TTL min The maximum of the two; if MAX_HOP t Greater than TTL max, then set the next broadcast range to TTL max ; If MAX_HOP t Between TTL max and TTL min If MAX_HOP t -TTL t The result is compared with the threshold; if MAX_HOP t -TTL t If the result is greater than the threshold, the next broadcast range is set to MAX_HOP t ; Otherwise, set the next broadcast range to TTL t -1 and TTL min The maximum of the two.

[0050] Step 2: After the aircraft node receives the gateway announcement message broadcast by the base station, it calculates the remaining path time, path carrying capacity, path delay, path load utilization and other parameters of the aircraft node, and compares the calculation results with the corresponding fields carried in the received gateway announcement message. As long as the remaining path time, path carrying capacity, and path load utilization calculated by the aircraft node meet the corresponding conditions (the remaining path time and path carrying capacity are smaller than the corresponding fields carried in the gateway announcement message, and the path load utilization is larger than the corresponding fields carried in the gateway announcement message), the aircraft node updates the gateway announcement message and determines whether to broadcast according to the TTL value carried in the gateway announcement message. The calculation formulas for each quality parameter are as follows:

[0051] (1) Calculation formula for remaining path time:

[0052] L i =min{L cj},j=1,2,...,n

[0053] Where n is the number of aircraft on path i, L cj represents the remaining connection time of the jth link among all the links on the path i from the aircraft node to the base station. Assuming that the link formed by nodes m and k is a link on the path i from the node to the base station, the link remaining time L of the link formed by nodes m and k is c The calculation is as follows:

[0054]

[0055] Where (x m ,y m ) and (x n ,y n ) are the coordinates of nodes m and n, v m and v nis the velocity of node m and node n, θ m and θ n is the heading angle between node m and node n. R represents the communication radius of civil aircraft; where a = v m cosθ m -v n cosθ n , b = x m -x n , c = v m sinθ m -v n sinθ n , d = y m -y n .

[0056] (2) Path carrying capacity calculation formula:

[0057] C i =min{C j},j=1,2,...,n

[0058] Where n is the number of aircraft on path i, C j Indicates the carrying capacity of the jth aircraft node on the current path i.

[0059] C j =C j_max -C j_cur -b

[0060]

[0061] Among them C j_max is the maximum carrying capacity of node j, C j_cur is the current load of node j, b is the protection load of the aircraft node, r i represents the average packet arrival rate of data packets forwarded by node j from node i, k i It represents the average packet size of the data packets forwarded by node j from node i.

[0062] (3) Path delay calculation formula:

[0063]

[0064] Where n is the number of aircraft on path i, D node(j) It represents the delay of the data packet on path i from the previous hop of aircraft node j to aircraft node j.

[0065] (4) Path load utilization calculation formula:

[0066] LU i =min{U j}, j = 1, 2, ..., n

[0067] Where n is the number of aircraft on path i, U j represents the load utilization of node j on path i, C max is the total capacity of node j, C cur is the current load of node j.

[0068] Step 3: The aircraft node calculates the weight of each path through adaptive weighting technology based on the gateway announcement message received. When the aircraft node needs to communicate with the ground base station, it checks whether there is a routing table entry to the base station in its own routing table. If so, the path with the largest weight value is selected as the routing path from the node to the base station; if not, the passive gateway discovery mechanism is used to find the routing path to the base station.

[0069] (1) The adaptive weight technology calculates the weight value of each path as follows:

[0070] First, the metric parameters are scaled. Since the path remaining time and path carrying capacity have a positive impact on the path selection, the positive criterion metric scaling method is used for scaling. The calculation formula of the positive criterion metric scaling method is:

[0071]

[0072] Since path load utilization and path delay have a negative impact on path selection, negative criterion metric scaling is used for scaling. The calculation formula of negative criterion metric scaling is:

[0073]

[0074] Among them, M max Indicates the maximum value of the metric, M min Indicates the minimum value in the measurement value; where S ij represents the scaled value of parameter j in path i; then the final weight value of each path is calculated:

[0075]

[0076] where w j is the weight factor of each parameter,

[0077] Step 4: If the aircraft node that has established a connection with the base station does not receive the gateway announcement message broadcast by the base station within a period of time, the first reason may be that the base station to which the aircraft node is connected is invalid and the aircraft node cannot access the corresponding base station. The second reason may be that the aircraft node is in the passive area of ​​the base station and cannot receive the gateway announcement message broadcast by the gateway in real time. The aircraft node uses autonomous inquiry to perceive the link changes from the base station to the aircraft.

[0078] (1) When the aircraft node does not receive the gateway announcement message broadcast by the base station after four broadcast cycles or before the path lifetime expires, it broadcasts a gateway request message. If the aircraft node receives a gateway reply message from the base station or a node in the active area after sending the gateway request message, the corresponding routing table information is updated.

[0079] (2) If no gateway reply message is received within a period of time, the gateway request message will be broadcast again. If no corresponding gateway request message is received twice in a row, it is considered that the current aircraft node is in an isolated state. At this time, it must maintain connection with the ground base station through satellite relay.

[0080] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0081] The above embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents of the present invention, technicians can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A method for routing in an aviation ad hoc network based on end-to-end quality parameters, characterized in that: The following steps are involved: The base station dynamically adjusts the broadcast range of the gateway announcement message according to the hop count information of the source aircraft node registered to the current base station, and broadcasts the gateway announcement message; After receiving the gateway notification message, the aircraft node calculates the parameters including the remaining time of the aircraft node's path, path carrying capacity, path delay, and path load utilization, and compares the calculation results with the remaining time of the path, path carrying capacity, path delay, path load utilization and other fields carried in the received gateway notification message. If the corresponding conditions are met, the corresponding fields in the gateway notification message are updated; The aircraft node calculates the weight of each path through adaptive weighting technology based on the received gateway announcement message. When the aircraft node needs to communicate with the ground base station, the aircraft node routing table entry is checked. If there are multiple routing table entries to the relevant base station in the routing table, the path with the largest weight value is selected as the routing path from the node to the base station; if there is no routing table entry information from the aircraft node to the base station, it means that the node is not within the broadcast range of the base station's announcement message, and the passive gateway discovery mechanism is started; When the aircraft node does not receive the gateway notification message broadcast by the base station for a period of time, the aircraft node uses autonomous inquiry to perceive the link changes from the base station to the aircraft; The broadcast range of the gateway announcement message is dynamically adjusted according to the following formula: Among them, TTL min It is the minimum broadcast range set by the base station, TTL max It is the maximum broadcast range set by the base station, TTL t+1 is the broadcast range of the base station in the next time period, TTL t is the broadcast range of the base station at the current moment, MAX_HOP t is the maximum number of hops from each source aircraft node to which the base station sends a data packet in the tth time period, and threshold represents the allowed hop threshold; The parameters including the remaining path time, path carrying capacity, path delay, and path load utilization of the aircraft node are calculated, specifically including: (1) Calculation formula for remaining path time: L i =min{L cj },j=1,2,...,n Where n is the number of aircraft on path i, L cj represents the remaining connection time of the jth link among all the links on the path i from the aircraft node to the base station; assuming that the link formed by nodes m and k is a link on the path i from the node to the base station, the link remaining time L of the link formed by nodes m and k is c The calculation is as follows: Where (x m ,y m ) and (x n ,y n ) are the coordinates of nodes m and n, v m and v n is the velocity of node m and node n, θ m and θ n is the heading angle between node m and node n; R represents the communication radius of civil aircraft; where a = v m cosθ m -v n cosθ n , b = x m -x n , c = v m sinθ m -v n sinθ n , d = y m -y n (2) Path carrying capacity calculation formula: C i =min{C j },j=1,2,...,n Where n is the number of aircraft nodes on path i, C j Indicates the carrying capacity of the jth aircraft node on the current path i; C j =C j_max -C j_cur -b Among them C j_max is the maximum carrying capacity of node j, C j_cur is the current load of node j, b is the protection load of the aircraft node, r i represents the average packet arrival rate of data packets forwarded by node j from node i, k i represents the average packet size of the data packets forwarded by node j from node i; (3) Path delay calculation formula: Where D node(j) represents the delay of the data packet on path i from the previous hop of aircraft node j to aircraft node j; (4) Path load utilization calculation formula: READ i =min{U j },j1,2,...,n U j represents the load utilization of node j on path i, C max is the total capacity of node j, C cur is the current load of node j.

2. The method for routing in an aviation ad hoc network based on end-to-end quality parameters according to claim 1, characterized in that: The adaptive weighting technology calculates the weight value of each path, specifically including: firstly scaling the metric parameter, the metric scaling method of the positive criterion: Metric scaling for negative criteria: Where S ij represents the scaled value of parameter j in path i, M max Indicates the maximum value of the metric, M min Represents the minimum value in the metric; then calculate the final weight value of each path: Where S ij represents the scaled value of parameter j in path i, where w j is the weight factor of each parameter, 3. The method for routing in an aviation ad hoc network based on end-to-end quality parameters according to claim 2, characterized in that: The aircraft node senses the link changes between the aircraft node and the base station by autonomous inquiry, specifically including: when the aircraft node does not receive the gateway announcement message broadcast by the base station after 4 cycles or before the path lifetime is about to expire, it broadcasts a gateway request message. If the aircraft node subsequently receives a gateway reply message from the base station or other aircraft nodes, the corresponding routing table information is updated; if the gateway reply message is not received within a period of time, the gateway request message is broadcast again. If the corresponding gateway reply message is not received twice in a row, it is considered that the current aircraft node is in an isolated state, and at this time it must maintain a connection with the ground base station through satellite relay.

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