JP2006005768A - Communication quality calculation method, communication quality calculation program, and radio node - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication calculation method which can measure communication quality of radio communication by low cost. <P>SOLUTION: The invention is the communication quality calculation method which calculates communication quality of a radio link 112 between ad-hoc nodes in a ad-hoc network 111 including ad-hoc nodes with routing protocol processing parts 522 which mutually transmit and receive advertising messages. The ad-hoc nodes execute a procedure to record communication history of the advertising messages in a memory means, and a procedure to calculate communication quality of the radio link 112 according to a calculated value of the communication history and a predetermined calculation formula. Furthermore, the ad-hoc nodes execute a procedure to make a routing table used when data are transferred in the ad-hoc network 111 based on the calculated communication quality. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication quality calculation method, a communication quality calculation program, and a radio node.

  When the communication medium in the network system is wireless, communication data is often lost during transmission because the reliability is lower than that of a wired transmission path. Therefore, in a network including a wireless section, in order to realize high-speed and highly reliable data transmission, it is necessary to accurately estimate the communication quality of the wireless link in each layer constituting the network processing stack. Therefore, a technique for estimating the quality of a radio link and the quality of a route including a radio section in a radio communication system has been proposed.

  These quality estimation techniques are classified according to an OSI reference model (Open Systems Interconnection reference model). The OSI reference model has a data link layer (second layer) that secures a physical communication path with a communication partner and detects an error in data flowing through the communication path, and a communication path for delivering data to the partner. And a network layer (third layer) that defines the address of each device for making the selection, a seven-layer network hierarchy model. The MAC (Media Access Control) layer is a part of the data link layer, and defines a frame transmission / reception method, a frame format, an error detection method, and the like.

  For example, Patent Document 1 proposes a method of estimating a wireless band that can be used in a network layer based on wireless quality information of a data link layer.

Patent Document 2 proposes a method for estimating the quality of a radio link in the network layer without requiring acquisition of radio quality information from the data link layer. Specifically, the present invention relates to a method of using a network command such as traceroute and a method of using a TCP (Transmission Control Protocol) Syn (synchronize / start) message in order to estimate communication efficiency. The Syn message is a packet transmitted from the connection partner when starting a TCP connection. In order to realize these methods, it is assumed that a specific network command or TCP is implemented in the network device.
JP 2003-348642 A (paragraph [0007]) JP 2000-278320 A (paragraph [0012])

  In the conventional techniques mentioned above, it is necessary to independently prepare means for measuring or estimating communication quality separately from the routing protocol.

  First, in many existing technologies such as Patent Document 1, an estimated value of the quality of a radio link is calculated in a data link layer. As a result, the development cost of implementing quality measurement means for each data link layer communication method is increased, and the interface for the network layer routing protocol to acquire the communication quality acquired by the measurement means is also used in the data link layer. It takes time and effort to prepare each communication method. In other words, there are a wide variety of devices that carry the data link layer, and even if the devices implement the same data link protocol or MAC protocol, the routing protocol is the data link because the method of implementing the protocol differs depending on the manufacturing method and manufacturer. A framework and a mechanism for acquiring the radio link quality estimation result from the layer or the MAC layer must be prepared for each type of device.

  On the other hand, the method of estimating the quality of a radio link in the network layer such as Patent Document 2 uses a specific network command or TCP in the transport layer protocol in order to estimate the radio link quality. There are other existing technologies on the premise of this, but this premise greatly imposes restrictions on communication devices and communication methods in realizing the system.

  As mentioned above, the conventional technology requires a separate means for measuring or estimating the communication quality separately from the routing protocol, so that development costs are high and a network for measuring the communication quality is required. The spread of was suppressed.

  In view of the above, the main object of the present invention is to solve the above-described problems and to measure the communication quality of wireless communication at low cost.

In order to achieve the above object, the present invention provides a communication quality calculation method for calculating communication quality of a radio link between radio nodes in a radio network including a radio node having a routing protocol processing unit that transmits and receives advertisement messages to and from each other. There,
A procedure in which the calculation means of the wireless node records the communication history of the advertisement message in a storage means; and a procedure of calculating communication quality of the wireless link according to a value calculated from the communication history and a predetermined calculation formula. It is characterized by executing.

  As a result, it is possible to estimate the quality of the radio link and the route including the radio section which change every moment in the routing protocol without preparing a means for measuring or estimating the communication quality independently from the routing protocol. Can do. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

  The present invention provides the communication quality calculation method comprising the steps of creating a routing table used when the calculation means of the wireless node transfers data in the wireless network based on the calculated communication quality. , Further executing.

  As a result, a value indicating the quality of the radio link is used as a metric for route control, or a value obtained by estimating the quality of the route including the radio section is used. It is possible to provide high-quality communication along a high-speed and high-bandwidth route. The metric uses a value of 1 or 0 indicating the presence / absence of a link, a bandwidth, a delay, and the like.

  According to the present invention, the procedure for recording the communication history of the advertisement message in the storage means is the advertisement broadcast from a wireless gateway, which is a wireless node capable of communicating with a node outside the wireless network by the computing means of the wireless node. The message is recorded in the communication history.

  This makes it possible to select an efficient route when communicating from the wireless network to an external network.

  In the present invention, the procedure for calculating the communication quality of the radio link is characterized in that the calculation means of the radio node selects the predetermined calculation formula from the type of transmission method in the data link layer of the advertisement message. .

  Thereby, the accuracy of the calculation result of the communication quality is improved by considering the type of the data link layer.

  The present invention is characterized in that the procedure for calculating the communication quality of the radio link is such that the calculation means of the radio node uses the success rate of reception of the advertisement message as a value calculated from the communication history.

  As a result, it is possible to estimate the quality of the radio link and the route including the radio section which change every moment in the routing protocol without preparing a means for measuring or estimating the communication quality independently from the routing protocol. Can do. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

  According to the present invention, the procedure for calculating the communication quality of the radio link is such that the calculation means of the radio node calculates a reception delay time of the advertisement message calculated from a difference between a reception time and a reception time of the advertisement message. The value is calculated from the communication history.

  As a result, it is possible to estimate the quality of the radio link and the route including the radio section which change every moment in the routing protocol without preparing a means for measuring or estimating the communication quality independently from the routing protocol. Can do. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

  The present invention is a communication quality calculation program for causing a computer to execute the communication quality calculation method.

  As a result, it is possible to estimate the quality of the radio link and the route including the radio section which change every moment in the routing protocol without preparing a means for measuring or estimating the communication quality independently from the routing protocol. Can do. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

The present invention provides a wireless network including a wireless node having a routing protocol processing unit that transmits and receives advertisement messages to and from each other, and calculates the communication quality of a wireless link between the wireless nodes,
The routing protocol processing unit is configured to record a communication history of the advertisement message and calculate communication quality of the wireless link according to a value calculated from the communication history and a predetermined calculation formula. .

  As a result, it is possible to estimate the quality of the radio link and the route including the radio section which change every moment in the routing protocol without preparing a means for measuring or estimating the communication quality independently from the routing protocol. Can do. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

  In the present invention, the wireless node is configured such that the routing protocol processing unit creates a routing table used when transferring data in the wireless network based on the calculated communication quality. It is characterized by that.

  As a result, a value indicating the quality of the radio link is used as a metric for route control, or a value obtained by estimating the quality of the route including the radio section is used. It is possible to provide high-quality communication along a high-speed and high-bandwidth route. The metric uses a value of 1 or 0 indicating the presence / absence of a link, a bandwidth, a delay, and the like.

  According to the present invention, the wireless node records the advertisement message broadcast from a wireless gateway, which is a wireless node capable of communicating with a node outside the wireless network, in the communication history. It is characterized by being configured.

  This makes it possible to select an efficient route when communicating from the wireless network to an external network.

  According to the present invention described above, the means for measuring or estimating the communication quality is not provided independently from the routing protocol. Quality can be estimated. Therefore, it is possible to measure the communication quality of wireless communication at a low cost.

  Hereinafter, a first embodiment illustrating a configuration of an ad hoc network and a communication quality calculation process between ad hoc nodes will be described as an example of applying the wireless network described in the claims to an ad hoc network. The wireless node recited in the claims corresponds to an ad hoc node, and the wireless gateway recited in the claims corresponds to an ad hoc gateway.

  Each ad hoc node constituting the ad hoc network is configured as a computer including at least a memory serving as a storage unit used when performing arithmetic processing and an arithmetic processing device (calculating unit) that performs the arithmetic processing. The memory is constituted by a RAM (Random Access Memory) or the like. Arithmetic processing is realized by an arithmetic processing unit configured by a CPU (Central Processing Unit) executing a program on a memory. Furthermore, each ad hoc node has wireless communication means such as an 802.11 standard wireless LAN or Bluetooth (R), and communication between ad hoc nodes is performed via this wireless communication means.

  When the ad hoc node AN1 and the ad hoc node AN2 having the internal configuration shown in FIG. 1 exist at positions where they can receive radio waves emitted from each other as shown in FIG. 2, the ad hoc node AN1 and the ad hoc node AN2 The wireless link 112 exists between the ad hoc node AN1 and the ad hoc node AN2 in a state of adjacency capable of direct communication. Then, the data amount or the number of packets of the routing protocol advertisement message that can be received from the ad hoc node AN2 per unit time by the ad hoc node AN1 is regarded as the quality of the wireless link 112 as the communication efficiency. Thus, it is a feature of the present invention that the ad hoc node AN1 calculates the communication quality of the radio link 112 with the ad hoc node AN2. The routing protocol includes, for example, an AODV (Ad hoc On-Demand Distance Vector) of RFC (Request For Comment) 3561 defined by the Internet Engineering Task Force (IETF), and the advertising message is an AODV Hello Message. It is done.

  The calculation means of the ad hoc node implements the following processing unit by executing a program. In the ad hoc node AN1 and the ad hoc node AN2, the same MAC protocol is implemented in the MAC protocol processing unit 513 and the MAC protocol processing unit 523. Similarly, the same routing protocol is installed in the routing protocol processing unit 512 and the routing protocol processing unit 522 in the ad hoc node AN1 and the ad hoc node AN2. Further, the same application is installed in the application layer processing unit 511 and the application layer processing unit 521 in the ad hoc node AN1 and the ad hoc node AN2.

  The routing protocol implemented in the routing protocol processing units 512 and 522 of the ad hoc node AN1 and the ad hoc node AN2 includes in advance specifications that periodically transmit an advertisement message to adjacent ad hoc nodes. The term “periodic” indicates that the time is predetermined, and may be the same time interval (such as every 10 seconds) or may be different time intervals. This specification is intended to periodically detect that ad-hoc nodes are adjacent to each other, and is included in many routing protocols. In other words, focusing on the ad hoc node AN1, the ad hoc node AN1 periodically receives an advertisement message from the ad hoc node AN2.

  Hereinafter, a flow of processing for calculating communication quality between ad hoc nodes will be described with reference to FIG.

  First, the wireless link 112 (see FIG. 2) exists between ad hoc nodes that are adjacent to each other. The wireless link 112 is a logical data transmission path created by a process in which each ad hoc node permits communication with the other ad hoc node by exchanging messages for starting routing protocol connection. That is, the ad hoc node AN1 and the ad hoc node AN2 know each other's existence by using the routing protocol. By establishing the wireless link 112, processing for calculating the communication quality of the wireless link 112 described later becomes possible.

  When the routing protocol processing unit 512 in the ad hoc node AN2 transmits the advertising message, the advertising message is passed to the MAC protocol processing unit 513 inside the ad hoc node AN2. The MAC protocol processing unit 513 confirms whether a transmission radio wave from another ad hoc node already exists, adds a header to the advertisement message, creates an advertisement message, and transmits the advertisement message wirelessly. If the wireless link 112 between the ad hoc node AN1 and the ad hoc node AN2 is sufficiently stable, the advertisement message transmitted by the ad hoc node AN2 is received by the MAC protocol processing unit 523 in the ad hoc node AN1 (S300).

  The routing protocol processing units 512 and 522 determine the type of the MAC protocol processing unit existing in the lower layer (S301 in FIG. 3). Usually, when the node communicates data, the data to be communicated is exchanged between the routing protocol processing units 512 and 522 and the MAC protocol processing units 513 and 523 via the MAC interface. When the routing protocol is used, the names and types of the MAC protocol processing units 513 and 523 are acquired.

Then, the advertisement message is passed to the routing protocol processing unit 522 in the ad hoc node AN1, and the data content of the advertisement message is extracted from the advertisement message. Note that the data content of the advertisement message is configured including transmission source identification information (IP address or the like).
Here, the advertisement message includes a first advertisement message for the ad hoc node to notify the location of the own device, or a second advertisement message for the ad hoc gateway to notify the location of the own device. Then, in order to cause each ad hoc node of the ad hoc network 111 to communicate with the outside of the ad hoc network 111, the second advertisement message is sequentially transferred from the received ad hoc node to another ad hoc node.
Thus, the ad hoc node AN1 receives the advertisement message that is periodically broadcast by the ad hoc node AN2.

  Next, the principle that the network layer in the ad hoc node AN1, that is, the routing protocol processing unit 522, can estimate the communication quality of the radio link and the radio link quality estimation method can be described.

  When the distance between the ad hoc node AN1 and the ad hoc node AN2 is short and the radio propagation environment is good, the ad hoc node AN1 can receive all advertisement messages that the ad hoc node AN2 periodically transmits. However, if the distance between the ad hoc node AN1 and the ad hoc node AN2 is long, the advertisement message may be lost on the radio, and the ad hoc node AN1 may not receive the advertisement message transmitted by the ad hoc node AN2.

  Since the advertisement message is periodically transmitted, the ad hoc node AN1 monitors the reception status of the advertisement message from the ad hoc node AN2 (S302). Then, the ad hoc node AN1 records the reception history (communication history) of the advertisement message from the ad hoc node AN2 in the storage unit.

  Next, the ad hoc node AN1 determines, for example, the number of advertisement messages from the ad hoc node AN2 from the ratio of the total number of advertisement messages scheduled to be received per unit time and the number of advertisement messages actually received per unit time. The probability p that cannot be received is calculated (S303). The probability p is observed in the routing protocol processing unit 522 in the ad hoc node AN1.

Next, based on the probability p (in other words, based on the reception success probability (1-p)), the communication quality of the wireless link 112 is estimated in the network layer (S304). When the application layer processing unit 511 of the ad hoc node AN2 transmits arbitrary data to the ad hoc node AN1, or more precisely to the application layer processing unit 521 in the ad hoc node AN1, the data is transmitted to the routing protocol processing unit. 512, and further passed to the MAC protocol processing unit 513. The MAC protocol processing unit 513 confirms whether a transmission radio wave from another ad hoc node already exists, adds a header to the data, creates a data frame, and transmits the data frame wirelessly. When the length of the data frame is L, the probability q that the data frame is lost during transmission can be expressed by (Equation 1). However, the length of the advertisement message is M.
q = 1- (1-p) ^{L / M} (Formula 1)

The expected value r of the transfer time when the data frame is received by the MAC protocol processing unit 523 without causing any error in the MAC protocol processing unit 513 is that the data frame is retransmitted in the MAC protocol processing unit 513. In other words, it is a value obtained by multiplying the time Ta required for reception by the MAC protocol processing unit 523 by (1-q) (see Equation 2). When an error occurs in the MAC protocol processing unit 513, the expected value s of the transfer time when the data frame is received by the MAC protocol processing unit 523 is the data when the MAC protocol processing unit 513 retransmits the data frame correctly. This is a value obtained by multiplying the time Tb required for the frame to be received by the MAC protocol processing unit 523 by q (see Equation 3). The sum T of r and s is an expected value of the time required for the data frame to be transmitted from the ad hoc node AN2 to the ad hoc node AN1.
r = Ta · (1-q) (Formula 2)
s = Tb · q (Formula 3)

  Therefore, the communication efficiency of the radio link 112 is obtained as a value obtained by dividing the length L of the data frame by T. The communication efficiency estimated as described above is the amount of data that can be received from the ad hoc node AN2 per unit time, indicates the bandwidth of the radio link 112, and indicates the communication quality of the radio link 112.

  Hereinafter, a second embodiment showing a route setting process based on communication quality between ad hoc nodes will be described.

  FIG. 4 shows an ad hoc network 111 including ad hoc nodes AN1 to AN6 and ad hoc gateways AG1 and AG2. Of the ad hoc nodes belonging to the ad hoc network 111, an ad hoc node connected to a network different from the ad hoc network 111 is referred to as an ad hoc gateway. That is, the ad hoc gateway is a kind of ad hoc node.

  Ad hoc nodes connected to each other are in a position where they can receive radio waves emitted from each other, and are in a state where they can directly communicate communication data using radio waves. The ad hoc nodes AN1 to AN6 constituting the ad hoc network have a function of relaying packets transmitted by other nodes (multi-hop communication function), and even nodes that are not in the direct wireless reachable range The ad hoc node can perform communication by relaying data one after another. For example, in the ad hoc network 111 of FIG. 4, the ad hoc node AN1 is not adjacent to the ad hoc node AN5 and cannot directly communicate radio waves, but the ad hoc node AN1 or the ad hoc node AN5 transmits data transmitted by radio waves. Can communicate with each other by relaying.

  Further, in order for the ad hoc node AN1 belonging to the ad hoc network 111 to connect to and communicate with the node N belonging to the public network 110, the ad hoc node AN1 has a function of connecting to the public network 110 and also belongs to the ad hoc network 111. The gateway AG1 or the ad hoc gateway AG2 must be connected using the multi-hop communication function.

  As specifications of the network layer protocol, the ad hoc gateway AG1 and the ad hoc gateway AG2 periodically broadcast a second advertisement message in the ad hoc network 111 in order to explicitly notify the ad hoc nodes AN1 to AN6 of their own existence.

  The advertisement message broadcasted by the ad hoc gateway AG1 is received by the ad hoc node AN1 via the relay by the ad hoc node AN6. If the communication quality of the route using the radio from the ad hoc gateway AG1 through the ad hoc node AN6 to the ad hoc node AN1 is good, the ad hoc node AN1 sends all advertisement messages periodically transmitted by the ad hoc gateway AG1 at substantially constant intervals. Can be received. However, if the communication quality of the route using the radio from the ad hoc gateway AG1 through the ad hoc node AN6 to the ad hoc node AN1 is not good, the ad hoc node AN1 cannot receive the advertisement message transmitted by the ad hoc gateway AG1, There are cases where the message reception interval is not constant.

  The flow of route setting processing based on the communication quality between ad hoc nodes will be described below with reference to FIG. The process shown in FIG. 5 is a process performed for each ad hoc gateway in the ad hoc node. Hereinafter, the processing will be described by focusing on the ad hoc gateway AG1 among the plurality of ad hoc gateways. First, the ad hoc node AN1 monitors the reception status of advertisement messages from the ad hoc gateway AG1 (S401), and records the history of receiving advertisement messages that the ad hoc gateway AG1 broadcasts periodically.

  Next, the ad hoc node AN1 calculates a probability p1 that the advertisement message from the ad hoc gateway AG1 cannot be received (S402).

  Then, the ad hoc node AN1 calculates a quality value representing the quality of the multi-hop route between the ad hoc node AN1 and the ad hoc gateway AG1 based on the probability p1 and the probability p2 that the advertisement packet cannot be received (S403). The calculation method is determined by the network layer protocol after determining the type of data link layer or MAC layer (for example, Bluetooth (R), IEEE 802.11 standard wireless LAN, etc.). Since the largest cause of packet loss on the route is that the radio link is unstable, the quality value represents the quality of the radio wave on the route between the ad hoc node AN1 and each ad hoc gateway.

  Also, since the ad hoc node AN1 periodically transmits the advertisement message by the ad hoc gateway AG1, in S404, the ad hoc node AN1 records the time when the advertisement message is received, so that the advertisement message is originally ad hoc. It is possible to detect how late it is received with respect to the time to arrive at the node AN1. This delay time is assumed to be t1.

  Then, the ad hoc node AN1 calculates a quality value indicating the quality of the multi-hop route between the ad hoc node AN1 and the ad hoc gateway AG1 from the delay time t1 of the advertisement message arrival time (S405). The calculation method is an arbitrary estimation method modeled in accordance with the device and protocol to be used. Due to the internal processing of the ad hoc node and the influence of congestion due to other communication traffic, the quality value represents the degree of delay time of the path between the ad hoc node AN1 and the ad hoc gateway AG1.

  Further, the ad hoc node AN1 determines the route quality by comparing the two types of multi-hop quality values calculated in S403 and S405 with respect to the ad hoc gateway AG1 (S406).

  The route setting process focusing on the ad hoc gateway AG1 has been described above with reference to FIG. This route setting process is similarly performed for other ad hoc gateways such as the ad hoc gateway AG2. Thereby, for example, it is possible to connect to the ad hoc gateway with the lowest probability of not receiving the advertisement message and the shortest arrival delay time value of the advertisement message, and then connect to the node N of the public network 110. it can.

  Each ad hoc node creates a route table (routing table) of its own device based on the result of measuring the communication quality of the wireless link 112 that is its own device. In this case, the communication quality is added to the attribute information of the route as a cost (metric) for reaching the predetermined route. Each ad hoc node selects a wireless link 112 having the smallest metric (in other words, the best communication quality) when a plurality of route candidates are searched by the route table when forwarding a packet. , Forward the packet to the selected wireless link 112.

  The embodiment of the present invention has been described above. In summary, an ad hoc node constituting an ad hoc network already has a routing protocol advertisement message transmission / reception process as an essential process. The advertisement message is used not only for establishing a wireless link between adjacent nodes, which is a conventional purpose, but also for measuring the communication quality of the wireless link and using the measured communication quality in a routing table. It becomes the feature. This makes it possible to reduce the development cost and development period for the communication quality measurement process by diverting the advertisement message of the routing protocol that has already been implemented, and the ad hoc network that can perform the communication quality measurement process. Promotion can be promoted. Furthermore, it is possible to provide high-quality communication quality such as low delay and wide bandwidth by utilizing the measured communication quality in the routing table.

  The present invention described above can be widely modified without departing from the spirit thereof as follows.

  For example, the ad hoc node may be realized by a mobile terminal such as a mobile phone, or may be realized by a personal computer such as a desktop.

It is a figure which shows the internal software structure in the node regarding one Embodiment of this invention. It is a figure which shows the positional relationship of the node regarding one Embodiment of this invention, and the wireless link between them. It is a figure showing the flow of a calculation process of the communication quality between the ad hoc nodes regarding one Embodiment of this invention. 1 is a configuration diagram of an ad hoc network and a public network according to an embodiment of the present invention. It is a figure showing the flow of the setting process of the path | route based on the communication quality between the ad hoc nodes regarding one Embodiment of this invention.

Explanation of symbols

AN2 Ad hoc node 110 Public network 111 Ad hoc network 112 Radio link 522 Routing protocol processing unit

Claims (10)

In a wireless network including a wireless node having a routing protocol processing unit that transmits and receives advertisement messages to and from each other, a communication quality calculation method for calculating communication quality of a wireless link between the wireless nodes,
A procedure in which the calculation means of the wireless node records the communication history of the advertisement message in a storage means; and a procedure of calculating communication quality of the wireless link according to a value calculated from the communication history and a predetermined calculation formula. A communication quality calculation method that is executed.   The communication quality calculation method further executes a procedure in which the calculation means of the wireless node creates a route table used when transferring data in the wireless network based on the calculated communication quality. The communication quality calculation method according to claim 1.   The procedure for recording the communication history of the advertisement message in the storage means includes: the advertisement message broadcast from a wireless gateway that is a wireless node capable of communicating with a node outside the wireless network by the computing means of the wireless node; The communication quality calculation method according to claim 1, wherein the communication quality is recorded in a communication history.   The procedure for calculating the communication quality of the radio link is characterized in that the calculation means of the radio node selects the predetermined calculation formula from the type of transmission method in the data link layer of the advertisement message. The communication quality calculation method according to claim 3.   The procedure for calculating the communication quality of the radio link is characterized in that the calculation means of the radio node sets the successful reception probability of the advertisement message as a value calculated from the communication history. 5. The communication quality calculation method according to any one of 4 above.   The procedure for calculating the communication quality of the radio link is such that the calculation means of the radio node calculates the reception delay time of the advertisement message calculated from the difference between the scheduled reception time and the reception time of the advertisement message from the communication history. The communication quality calculation method according to any one of claims 1 to 4, wherein the communication quality is calculated.   A communication quality calculation program for causing a computer to execute the communication quality calculation method according to any one of claims 1 to 6. In a wireless network including a wireless node having a routing protocol processing unit that transmits and receives advertisement messages to and from each other, the wireless node calculates communication quality of a wireless link between the wireless nodes,
The routing protocol processing unit is configured to record a communication history of the advertisement message in a storage unit, and to calculate communication quality of the wireless link according to a value calculated from the communication history and a predetermined calculation formula. A featured wireless node.   The wireless node is configured such that the routing protocol processing unit creates a routing table used when transferring data in the wireless network based on the calculated communication quality. The wireless node according to claim 8. The wireless node is configured such that the routing protocol processing unit records the advertisement message broadcast from a wireless gateway, which is a wireless node capable of communicating with a node outside the wireless network, in the communication history. The wireless node according to claim 8 or 9, wherein:

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