JP2019134315A - Wireless communication apparatus, wireless communication system, wireless communication program, and wireless communication method - Google Patents

Abstract

To make it possible to quickly evaluate an evaluation value of communication quality of a communication path between stations even in a network including a mobile station with rapid movement or rotation.SOLUTION: In the wireless communication system, a plurality of mobile stations includes: transmission/reception means for transmitting/receiving radio waves to/from the base station or other mobile stations; route generation packet receiving means for receiving a route generation packet from a radio signal received by the transmission/reception means; movement measuring means for measuring a moving speed of an own station; and management means for deriving an evaluation value of a communication path from a transmission station of a route generation packet at least on the basis of a received power value of the radio wave at a time of receiving a route generation packet and a moving speed of the own station by referring to predetermined link cost information.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a wireless communication device, a wireless communication system, a wireless communication program, a wireless communication method, and a link evaluation method, for example, a fixed wireless communication device (hereinafter also referred to as “base station”) and a movement of a human or the like. The present invention can be applied to a wireless communication system configured by a wireless communication device (hereinafter also referred to as “mobile station”) attached to the body.

  Conventionally, various methods have been proposed for selecting a transfer path in a multi-hop network.

  For example, when each mobile station transmits data in a multi-hop direction to a fixed base station, the base station is set to “root”, each mobile station is set to “node”, “leaf”, and the communication link between the stations It is necessary to construct a tree structure with the “branch” as. The communication quality of the network varies depending on which branch is used. Therefore, an evaluation value (hereinafter referred to as “link cost”) for evaluating communication quality is given to each branch, and the sum of link costs from each mobile station to the base station (hereinafter referred to as “path cost”). .) Is often used (see Patent Document 1). The link cost is set such that the value becomes smaller as the link has better communication quality.

  Conventionally, the link cost is often a communication success rate between stations or a received power value. This is because the result of measuring the communication quality is adopted as the link cost on the assumption that the mobile station does not move much.

JP2015-43637A

  However, the conventional technique, for example, collects predetermined data from a mobile station in which a wireless communication device is attached to a mobile body that performs a relatively fast moving motion or rotational motion, in the base station. Due to the intense movement, the method of measuring communication quality over time cannot be used. In addition, there is a problem that the communication quality greatly changes when the mobile station rotates due to the directivity problem of the radio antenna attached to the mobile body.

  Therefore, a wireless communication device, a wireless communication system, a wireless communication program, and a wireless communication capable of quickly evaluating an evaluation value of communication quality of a communication path between stations even in a network including mobile stations with rapid movement or rotation There is a need for a method.

  In order to solve the above-described problem, a wireless communication device according to a first aspect of the present invention includes: (1) a transmission / reception unit that transmits / receives a radio wave; and (2) a route generation packet from a radio signal received by the transmission / reception unit. (3) a movement measuring means for measuring the moving speed of the local station, and (4) referring to predetermined link cost information, and at least the radio wave at the time of receiving the path generating packet. Management means for deriving an evaluation value of the communication path between the transmission station of the path generation packet based on the received power value and the moving speed of the own station is provided.

  A radio communication system according to a second aspect of the present invention is a radio communication system configured to include a fixed station and a plurality of mobile stations, and each mobile station includes the radio communication apparatus according to the first aspect of the present invention. It is characterized by that.

  According to a third aspect of the present invention, there is provided a wireless communication program comprising: (1) a transmission / reception unit that transmits / receives a radio wave; and (2) a route generation packet that receives a route generation packet from a radio signal received by the transmission / reception unit. Receiving means; (3) movement measuring means for measuring the moving speed of the own station; and (4) referring to predetermined link cost information, at least the received power value of the radio wave at the time of receiving the route generation packet and the own station. And a management means for deriving an evaluation value of a communication path between the transmission station of the path generation packet based on the moving speed of the path generation packet.

  According to a fourth aspect of the present invention, there is provided a wireless communication method in which (1) a transmission / reception unit receives a radio wave, and (2) a route generation packet reception unit receives a route generation packet from a radio signal received by the transmission / reception unit. (3) The movement measurement means measures the moving speed of the own station, and (4) the management means refers to predetermined link cost information, and at least the reception power value of the radio wave at the time of receiving the route generation packet And an evaluation value of the communication path between the transmission station of the path generation packet based on the mobile station and the moving speed of the local station.

  According to the present invention, even in a network including mobile stations with rapid movement and rotation, it is possible to quickly evaluate the communication quality evaluation value of the communication path between stations.

1 is an overall configuration diagram illustrating an example of an overall configuration of a wireless communication system according to an embodiment. It is explanatory drawing explaining an example of the reception power characteristic of the mobile station which concerns on embodiment. It is explanatory drawing explaining an example of the link cost in the radio | wireless communications system which concerns on embodiment. It is explanatory drawing explaining an example of the relationship between the moving speed and maximum rotation angle in embodiment. It is a rotation angle generation probability distribution diagram showing an example of the generation probability (occurrence frequency) of the rotation angle of each moving speed in the embodiment. It is a fluctuation probability distribution diagram of the received power value showing an example of the fluctuation probability density of the received power value at each rotation angle in the embodiment. It is explanatory drawing explaining the derivation method of a reception failure rate based on the fluctuation probability density of the reception power value of the mobile station after movement in embodiment. It is a block diagram which shows an example of the link cost table in embodiment. It is a figure which shows the relationship between the distance between transmission / reception points and received power value in embodiment. It is an internal block diagram which shows an example of the internal structure of the mobile station which concerns on embodiment. In embodiment, it is explanatory drawing explaining derivation | leading-out of the path cost in a mobile station. It is a functional block diagram which shows the structure of the link evaluation apparatus which concerns on embodiment.

(A) Main Embodiments Hereinafter, embodiments of a wireless communication device, a wireless communication system, a wireless communication program, and a wireless communication method according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 1 is an overall configuration diagram illustrating an example of an overall configuration of a wireless communication system (network) according to an embodiment.

  As shown in FIG. 1, the wireless communication system 1 assumed in this embodiment includes a fixed base station 10 and a plurality (eight in FIG. 1) of mobile stations 20 (20-1 to 20-8). ) To form a network.

  The wireless communication system 1 constitutes a wireless multi-hop network having a tree structure in which the base station 10 is “root” and each mobile station 20 is “node” and “leaf”. In the wireless communication system 1, the number of base stations 10 and mobile stations 20 is not limited. Hereinafter, the base station 10 and the mobile station may be collectively referred to as a station or a node. In FIG. 1, a straight line connecting the stations indicates that the two stations can communicate.

  Each of the base station 10 and the mobile station 20 is assigned a unique address (for example, a MAC address, a short address, an IP address, etc.) on the network. Although communication is performed between the base station 10 and each mobile station 20, communication between the mobile stations 20 is not performed. If communication between the mobile stations 20 is necessary, communication may be performed via the base station 10. That is, in principle, each mobile station 20 transmits a unicast data packet with the base station 10 as the destination, but does not transmit a unicast data packet with the other mobile station 20 as the destination. .

  The base station 10 is a wireless communication device that is fixedly arranged, and manages the entire wireless communication system 1. The base station 10 is also called a fixed station.

  Each mobile station 20 (20-1 to 20-8) is a wireless communication device attached to a mobile body. As the moving body, for example, a movable body such as a human being, a bicycle, or an automobile can be widely applied.

  In this embodiment, for example, it is assumed that the mobile body is a human and the wireless communication device as the mobile station 20 is fixed in contact with the human body by a wearing device such as a band or a vest-type wearing clothing. To explain. For example, a wireless communication device as the mobile station 20 is equipped with one or a plurality of sensors, and acquires pulse data, heart rate data, etc. of a human body at a fixed position, or a base station as necessary. This is because it is assumed that the data is transmitted to 10. Note that the type of data to be sensed is not particularly limited. The position where the wireless communication device is fixed to the moving body is appropriately determined according to the data to be measured and the type of exercise.

  FIG. 2 is an explanatory diagram illustrating an example of reception power characteristics of the mobile station 20 according to the embodiment.

  Here, the received power characteristic received by the radio of the mobile station 20 when the mobile station 20 is attached to a human back is illustrated. Since the radio of the mobile station 20 is attached to the back of the human body, the human body can be an obstacle. That is, the 0 degree direction of the antenna of the mobile station 20 is behind the human body, and the 180 degree direction is the front of the human body. Referring to FIG. 2, it can be seen that the dip is deep in the direction of 180 degrees of the antenna of the mobile station 20, and the reception characteristics in the direction penetrating the human body centering on 180 degrees are deteriorated. Therefore, for example, when the mobile station 20 is used while being attached to a human body, the human body becomes an obstacle and affects the communication quality depending on the positional relationship with another station that is a communication partner.

  FIG. 3 is an explanatory diagram illustrating an example of the link cost in the wireless communication system 1 according to the embodiment.

  In FIG. 3, thick lines indicate data transfer paths between stations, and dotted lines indicate links that are not used for transfer. The numbers in square boxes attached to each link indicate the link cost, and the numbers attached to each mobile station 20 indicate the path cost of each mobile station. The path cost of the base station 10 is “0”.

  For example, the transfer path from the mobile station 20-6 to the base station 10 is “mobile station 20-6” → “mobile station 20-4” → “base station 10”. In this case, since the link cost between the mobile station 20-4 and the base station 10 is “4”, when the mobile station 20-4 transfers data to the base station 10 using this communication path, The path cost of the station 20-4 is “4”. Further, the link cost between the mobile station 20-6 and the mobile station 20-4 is “2”, and the mobile station 20-6 selects the mobile station 20-4 as a transfer destination and transmits data to the base station 10. In this case, the path cost of the mobile station 20-6 is “6 (= 2 + 4)”.

  The link cost is a value obtained by evaluating the communication quality of the communication path between stations. There are various ways of evaluating the link. For example, the communication quality of the communication channel is evaluated by a value in the range of “1 to 99”, “1 to 9999”, etc. In general, the smaller the value, the better the communication quality. The higher the value, the worse the communication quality. That is, if the value of the link cost is “1”, it is determined that the communication quality of the communication path is good.

[Link evaluation equipment]
Each mobile station 20 evaluates the communication quality (link cost) of a communication path with another station (base station 10 or other mobile station 20), and derives the link cost of each communication path 200.

  Each mobile station 20 may have a link evaluation device 200 described below and perform communication every time. Alternatively, as will be described later, the link evaluation device 200 preliminarily moves the distance of its own station. A two-dimensional table (link cost table) indicating the link cost based on the relationship between the received power value and the link power table may be obtained.

  Hereinafter, an example of the configuration of the link evaluation device 20 according to the embodiment and a method for deriving the link cost will be described with reference to the drawings.

  FIG. 12 is a functional block diagram illustrating a configuration of a link evaluation apparatus included in each mobile station 20 according to the embodiment.

  As illustrated in FIG. 12, the link evaluation apparatus 200 includes a rotation angle occurrence frequency deriving unit 1, a received power fluctuation characteristic deriving unit 2, a communication failure rate estimating unit 3, and a link cost deriving unit 4.

  The hardware configuration of the link evaluation apparatus 200 is not shown, but includes, for example, a PU, ROM, RAM, EEPROM, input / output interface, etc., and a processing program (link evaluation program) in which the CPU is stored in the ROM. May be executed. The link evaluation function may be executed by the CPU by installing the link evaluation program. Even in this case, the link evaluation program has a function as illustrated in FIG.

  The link evaluation device 200 of each mobile station 20 receives a beacon signal (beacon packet) periodically flooded from the base station 10 and uses the received power value at the time of receiving the beacon as a reference. Further, as will be described later, each mobile station 20 has a movement measuring means for measuring a movement amount (that is, a moving speed of the own station) of the own station for a fixed time, and a link evaluation device for each mobile station 20. 200 uses the moving speed obtained by the movement measuring means. Here, flooding means that a node that receives a packet (for example, a flooding packet as a route generation packet) transmits the same packet only once to send information to all nodes in the multihop network. .

  When each mobile station 20 floods (transmits) a beacon signal, the mobile station 20 performs flooding (transmits a beacon) by describing the value of its own moving speed associated with its own identification information in the beacon. In other words, the beacon packet includes the moving speed associated with the identification information of each mobile station 20.

  The link evaluation device 200 obtains a fluctuation distribution of the received power value based on both or either of the moving speed of the beacon transmitting station and the moving speed of the own station (beacon receiving station). Based on the probability density of the received power obtained as a result, the communication success rate (or communication failure rate) when the communication path with the beacon transmission station is used is estimated. The link cost value is derived based on the communication success rate (or communication failure rate) when communication is performed using this communication path.

  Here, it is considered that the fluctuation of the moving speed and the received power corresponds to one to one. Therefore, it is not necessary to consider the probability density of received power every time a beacon is received, and the probability density of received power can be obtained directly from the moving speed.

  On the other hand, it is known that if the moving distance for a certain time (for example, 1 second) is large, the possibility of rotation decreases, and if the moving distance is short, the possibility of rotation increases.

  FIG. 4 is an explanatory diagram illustrating an example of the relationship between the moving speed and the maximum rotation angle. The maximum rotation angle means the maximum angle that can be rotated while maintaining the movement speed when the movement direction is 0 degree when moving at a certain movement speed.

  As shown in FIG. 4, when the moving speed is low (moving speed: Va), the maximum rotation angle (rotating angle: θa) is relatively large, and when the moving speed is increased (moving speed: Vb (> Va) maximum rotation). The angle is small (rotation angle: θb (<θa)), that is, when the moving speed becomes large, it does not rotate suddenly and only takes a rotation angle below a certain value. A relatively large rotation angle can be taken.

  The rotation angle occurrence frequency deriving unit 1 derives the occurrence probability of the rotation angle of the own station at the moving speed of the own station. At each of a plurality of movement speeds, the probability of occurrence (occurrence frequency) of the rotation angle of the mobile station 20 itself is derived.

  FIG. 5 is a rotation angle occurrence probability distribution diagram showing an example of the occurrence probability (occurrence frequency) of the rotation angle at each moving speed.

  The occurrence probability (occurrence frequency) of the rotation angle means the occurrence frequency of the rotation angle when the rotation direction is 0 degrees when moving at a certain moving speed. In FIG. 5, as an example for ease of explanation, a case where the movement speed illustrated in FIG. 4 is large (movement speed: Va) and a case where the movement speed is small (movement speed: Vb) are compared. Actually, assuming the movement of each mobile station 20, a plurality of movement speeds having different values may be set, and the occurrence probability (occurrence frequency) of the rotation angle at each movement speed may be obtained. As shown in FIG. 5, the occurrence probability (occurrence frequency) is highest regardless of the moving speed when the rotation angle is 0, that is, when no rotation occurs. Further, it can be seen that the occurrence probability (occurrence frequency) rapidly decreases as the rotation angle increases regardless of the moving speed. When the cases where the moving speeds are different are compared, the slope at which the occurrence probability decreases increases as the moving speed increases.

  The received power fluctuation characteristic deriving unit 2 obtains fluctuation characteristics of the received power value when the mobile station 20 rotates.

  FIG. 6 is a received power value fluctuation probability distribution diagram illustrating an example of a received power value fluctuation probability density at each rotation angle.

  Here, using the reception power characteristic as shown in FIG. 2 as the reception power characteristic of the radio of each mobile station 20, when each mobile station 20 rotates by X degrees, the fluctuation characteristic of the reception power value is derived. . That is, when a mobile station 20 communicating with another mobile station 20 rotates X degrees, a variation probability density of the received power value indicating the relative ease with which the received power value variation amount (variation value) is generated is derived. To do. Note that the received power characteristics of the mobile station 20 are not limited to the received power characteristics shown in FIG. 2, but the received power related to the angle of the radio (antenna) of the mobile station 20 attached to the mobile body. Any device that exhibits characteristics (antenna characteristics) may be used.

  A specific method for deriving the fluctuation probability density of the received power value will be exemplified. As illustrated in FIG. 2, the reception power characteristic (antenna characteristic) of the radio of the mobile station 20 when the mobile station 20 is attached to the back of the human body is 0 degree with respect to the radio (antenna). It has become a direction. When a certain mobile station 20 is communicating with another station (base station 10 or another mobile station 20), the angle of the communication direction between the mobile station 20 and the other station is set to Y degrees.

  The communication direction before movement is Y degrees, and the communication direction after movement is (Y + X) degrees or (Y−X) degrees. Therefore, based on the received power characteristic of FIG. 2, the difference value (received power fluctuation value) between the Y degree antenna characteristic and the (Y + X) degree antenna characteristic, the Y degree antenna characteristic and the (Y−X) degree antenna. A difference value (received power fluctuation value) from the characteristic is derived. At this time, as described above, since the value of the angle Y, which is the communication direction before movement, is a value within the range of 0 degrees to 360 degrees, all Y values are derived.

  In FIG. 6, in order to explain the variation probability density of the received power value (the variation characteristic of the received power value) by comparing the case where the mobile station 20 rotates largely and the case where the mobile station 20 rotates slightly, the value of the angle X is 10 The case of degrees and the case of 40 degrees are shown. Since the value of the rotation angle X is a value within the range of 0 degrees to 180 degrees, the fluctuation characteristics of the received power value may be derived for all the X values. As shown in FIG. 6, when the rotation angle is small, the amount of variation in received power is small, and when the rotation angle is large, the amount of variation in received power is large.

  The communication failure rate estimation unit 3 refers to the information on the reception failure rate (packet loss rate) with respect to the received power value, and based on the received power value as a reference and the fluctuation probability density of the received power value, Estimate the communication failure rate.

  FIG. 7 is an explanatory diagram for explaining a method for deriving the reception failure rate based on the fluctuation probability density of the reception power value in the mobile station 20 after movement.

  Based on the reference received power value and the fluctuation probability density of the received power value, the probability density value of the received power value after movement is derived. Then, referring to the relationship between the reception failure rate (packet loss rate) for each received power value, the probability density value of the received power value after movement (that is, the occurrence probability A of the received power value) Multiply the reception failure rate (packet loss rate) with the received power value. By calculating for all received power values and adding the calculation results, the communication failure rate after movement in a specific situation can be estimated.

  The link cost deriving unit 4 evaluates the communication quality of a link with another station based on the communication failure rate estimated by the communication failure rate estimating unit 3, and derives a link cost value for the link. It is. Since the link cost increases as the communication quality deteriorates, the reciprocal of the communication success rate may be used as an example.

  As described above, each mobile station 20 may include the link evaluation device 200 and derive the link cost in consideration of the moving speed and rotation of the mobile station 20 for each communication.

  However, after all, since the moving speed of the mobile station 20 and the received power value before moving in the mobile station 20 become variables, the relationship between the moving speed and the received power value before moving is illustrated in FIG. A link cost table (hereinafter also referred to as “link cost information”), which is a two-dimensional table indicating the link cost based on, may be set in each mobile station 20. Thereby, it is possible to derive the corresponding link cost based on the moving speed and the received power value before the movement by referring to the preset link cost without requiring a complicated calculation for each communication.

  In addition, the information about the maximum rotation angle with respect to the moving speed (see FIG. 4) and the information about the frequency of occurrence of the rotation angle (see FIG. 5) can vary depending on, for example, the type of exercise and the situation. Accordingly, only one link cost table as illustrated in FIG. 8 is set, and not only a method of uniquely determining based on the moving speed and the received power value, but also a plurality of link cost tables are set, Depending on the situation, the link table to be used may be switched so that the optimum link cost can be derived according to the situation.

[Mobile station 20]
FIG. 10 is an internal configuration diagram illustrating an example of an internal configuration of the mobile station 20 according to the embodiment.

  Here, an example in which the link evaluation method is implemented in the mobile station 20 is illustrated. Specifically, the link evaluation device 200 sets a link cost table (link cost information) in advance, and responds from the link cost table based on the received power value when the beacon packet is received and the moving speed of the local station. An example of deriving the link cost to be performed is illustrated.

  As shown in FIG. 10, the mobile station 20 includes a transmission unit 1001, a reception unit 1002, a timer 1003, a beacon packet generation unit 1004, a data generation unit 1005, a transmission destination selection unit 1006, a beacon reception unit 1007, a beacon management unit 1008, Data receiving means 1009, movement measuring means 1010, peripheral radio table 1011, link cost table 1012, and position measuring means 1013 are provided.

  The mobile station 20 is equipped with an integrated device such as a CPU, ROM, ROM, EEPROM, input / output interface, communication means (wireless interface), and the like. Various functions in the mobile station 20 are processed by the CPU (computer). This is realized by executing (wireless communication program).

  The transmission unit 1001 transmits a radio signal radio wave. The receiving unit 1002 receives radio waves of radio signals transmitted from other stations. In the mobile station 20, a transmission unit 1001 and a reception unit 1002 constitute a wireless interface (packet transmission / reception unit) that transmits and receives wireless signals. The mobile station 20 transmits and receives beacon packets between stations, and transmits and receives data packets including human body pulse data.

  The movement measuring unit 1010 is a movement recognition unit that performs a process of recognizing the movement status of the own station (hereinafter also referred to as “movement recognition process”). The movement measurement unit 1010 gives the movement recognition processing result to the beacon management unit 1008. In this embodiment, the movement measuring unit 1010 recognizes the movement amount (that is, the movement speed) of the own station in a certain time (the most recent certain time) as the movement recognition process. As the movement measuring unit 1010, various devices such as an acceleration sensor, a gyro sensor, an acceleration sensor, an angular acceleration sensor, and a geomagnetic sensor can be applied.

  The position measuring means 1013 is position recognition means for recognizing the position information of the own station. For example, a device such as a GPS receiver can be applied to the position measuring unit 1013. The position measuring means 1013 is not an essential element of this embodiment, but is used when the position information of the own station can be included in the beacon packet.

  The beacon receiving unit 1007 has a function of receiving beacon packets periodically transmitted by the base station 10 by flooding via the receiving unit 1002. The beacon receiving unit 1007 supplies the received power value at the time of receiving the beacon to the beacon managing unit 1008, or includes the moving speed of the transmitting station, the path cost of the transmitting station, and the transmitting station if necessary. Or the like is supplied to the beacon management means 1008.

  The beacon management unit 1008 acquires the beacon packet received from the beacon receiving unit 1007, and is responsible for the management of beacon packets and the beacon packet transfer control function. The beacon management unit 1008 obtains the path cost of the transmitting station included in the beacon from the beacon receiving unit 1007 (that is, the path cost associated with the identification information of the transmitting station), and the path of the mobile station in the vicinity. In order to hold the cost, the path cost of the transmitting station is stored in the peripheral radio table 1011. The beacon management unit 1008 receives the received power value at the time of receiving a beacon from the beacon receiving unit 1007 and the moving distance (moving speed) per fixed time measured by the movement measuring unit 1010, and the received power value at the time of receiving the beacon. And the speed of movement of the own station, it is responsible for determining the link cost between stations. Also, the beacon management unit 1008 refers to the peripheral wireless device table 1011 and selects a route with the lowest link cost from the own station to the base station 10 and uses the route when the communication is performed. Determine the station path cost.

  In this embodiment, the link cost table 1012 obtained in advance by the link evaluation apparatus 200 is used to determine the link cost between stations based on the received power value and the local station moving speed.

  However, the mobile station 20 may implement the link evaluation apparatus 200 so that the link cost between stations can be derived for each communication. In that case, the link evaluation device 200 may be provided in the beacon management unit 1008. Since the configuration of the link evaluation device 200 and an example of the link cost derivation method have already been described, a detailed description thereof will be omitted here.

  In addition to deriving the link cost as described above, the beacon management unit 1008 may perform the correction process of the link cost value in consideration of the following factors.

  The beacon management unit 1008 may derive the link cost in consideration of the influence of fading.

  When the received power value before movement is large, that is, when the distance between the data transmitting station and the data receiving station is short, the influence of fading due to ground reflection is severely affected. It is known.

  FIG. 9 is a diagram illustrating the relationship between the distance between the transmission and reception points and the received power value. As shown in FIG. 9, as the distance between the transmission and reception points increases, the amount of fluctuation (variation value) in the received power value with respect to a certain amount of movement decreases. Therefore, considering this factor, the beacon management unit 1008 has a large received power value (for example, the received power value is larger than the threshold value compared to the threshold value) and is moving rapidly (for example, the moving speed exceeds the threshold value). If the communication cost is high, there is a high possibility that the communication quality will change abruptly. Therefore, the link cost value may be increased.

  In addition, when the beacon packet includes the location information of the transmitting station, the beacon management unit 1008 derives the distance based on the location information of the transmitting station and the location information of the receiving station (that is, the own station), The received power value may be corrected based on the distance.

  For example, when the mobile station 20 can recognize the position information of its own station using position measurement means such as GPS, the beacon packet can be flooded by including the position information of the transmitting station. In that case, the distance between the transmitting and receiving stations can be derived based on the position information of the transmitting station and the position information of the own station included in the beacon packet. The received power value corresponding to the derived distance is corrected based on the relationship information between the distance and the received power value at the time of beacon reception. Specifically, the link evaluation apparatus 200 may be affected by fading or the like, and there may be a case where the received power becomes low despite the short distance. In such a case, the average received power value is corrected from the distance. To do.

  Further, the beacon management unit 1008 has the same influence on the communication performance due to rotation not only for the own station but also for the transmission / reception partner. Therefore, the link cost table 1012 illustrated in FIG. 8 can be expanded to take a method of obtaining the link cost from the three elements of the destination moving speed, the own moving speed, and the received power. For example, as an example, a plurality of link cost tables illustrated in FIG. 8 are prepared for each moving speed of the transmission destination, and a corresponding link cost table is selected based on the moving speed of the transmission destination. May be used to derive the link cost between stations.

  The link cost table 1012 is a link cost table obtained in advance by the link evaluation apparatus 200. For example, the link cost table illustrated in FIG. 8 can be applied to the link cost table 1012. In addition, the link cost table 1012 includes not only one type of link cost table but also a plurality of types of link cost tables depending on the status of wireless communication (for example, the type of exercise and the environmental status). Alternatively, any link cost table may be used.

  The link cost table 1012 is not limited to the link cost table illustrated in FIG. 8, and the link cost table 1012 uses the moving speed of the transmitting station of the beacon packet in addition to the moving speed and received power value of the own station. May be used as a link cost table having the moving speed of the own station, the received power value, and the moving speed of the transmitting station as elements.

  The timer 1003 is a timer for managing a delay (packet transfer delay time) from when a flooding packet is received from another station until the flooding packet is transferred.

  The beacon packet generation unit 1004 has a function of generating a beacon packet to be flooded. The beacon packet generation unit 1004 includes the beacon packet including the path cost of the own station, the moving distance of the own station as a transmitting station, and the position information of the own station as necessary.

  The data receiving unit 1009 has a function of receiving a data packet transmitted from another station via the receiving unit 1002. The data receiving unit 1009 gives the data packet that has undergone the receiving process to the transmission destination selecting unit 1006. For example, when the received data packet is transferred to the next station, the data receiving unit 1009 supplies the data packet to the transmission destination selecting unit 1006 in order to transfer to the next station.

  The data generation unit 1005 has a function of generating data to be transmitted to the base station 10. For example, human body pulse data is generated, but the data type is not particularly limited. The data transmission trigger of the data generation unit 1005 is not particularly limited, and, for example, data generated in an upper layer (such as an application (not shown)) can be used as transmission data.

  The peripheral wireless device table 1011 is a table including information related to the mobile station 20 located in the vicinity. The peripheral wireless device table 1011 includes, for example, information such as address information of peripheral mobile stations 1011 and the number of hops to the base station 10, and a route table or the like can be applied.

  The transmission destination selection unit 1011 has a function of selecting a transfer destination of data generated by the data generation unit 1005 or data received by the data reception unit 1009. The transmission destination selection unit 1011 refers to the peripheral radio table 1011 and selects a route having the minimum cost among routes from the local station to the base station 10 and stores the next mobile station on the route as data. Select as destination. Then, the data packet as the selected data transfer destination is supplied to the transmission unit 1001, and the data packet is transmitted from the transmission unit 1001 to the transfer destination.

(A-2) Operation of Embodiment Hereinafter, an operation of wireless communication processing in the wireless communication system 1 according to the embodiment will be described with reference to the drawings.

  In this wireless communication system 1, for example, a wireless communication device as a mobile station 20 is attached to a human body, and it is assumed that a person (mobile body) runs, and each mobile station 20 moves a lot. Reconfigure the network (for example, typically every second).

  In order for the beacon packet to reach each mobile station 20, the base station 10 transmits the beacon packet periodically (for example, every second).

  For example, in the case of the network configuration illustrated in FIG. 3, mobile stations 20 located in the vicinity of the base station 10 (that is, mobile stations within the radio wave reach of the base station 10) are mobile stations 20-1, 20-. 3, 20-5, and 20-7, the mobile stations 20-1, 20-3, 20-5, and 20-7 receive the beacon packet directly from the base station 10.

  In each mobile station 20 that has received the beacon packet, the receiving means 1002 captures the radio wave and measures the received power value when receiving the beacon. The beacon receiving unit 1007 supplies the received power value when the receiving unit 1002 receives the beacon and the received beacon packet to the beacon managing unit 1008.

  The beacon management unit 1008 acquires the path cost of the transmitting station included in the beacon packet, and stores the path cost of the transmitting station in the peripheral radio table 1010. Here, since the path cost of the base station 10 is set to “0”, the mobile station 20 that has directly acquired the beacon packet from the base station 10 sets the path cost “0” of the base station 10 to the peripheral radio table 1010. To remember. On the other hand, when the transmitting station of the beacon packet is the mobile station 20, the path cost of the mobile station 20 that is the transmitting station of the beacon packet is included in the beacon packet. Is stored in the peripheral radio table 1010.

  Also, the beacon management unit 1008 acquires the received power value at the time of receiving the beacon and the movement amount (movement speed) of the own station within a certain period from the movement measurement unit 1010, and refers to the link cost table 1012 to receive the beacon. Based on the received power value at the time and the moving speed of the local station, the link cost of the communication path between the transmitting station (base station 10 or mobile station 20) of the beacon packet and the local station is derived, and the link cost is Store in radio table 1010. Here, since the link cost between the transmitting station and the own station can be derived with reference to the link cost table 1012, even when a person runs and moves, the mobile station 20 moves violently. The link cost can be quickly derived while suppressing the processing load. Of course, the function of the link evaluation device 200 may be installed in the beacon management unit 1008, and the link evaluation device 200 may sequentially derive the link cost when a beacon is received.

  Further, immediately before the beacon packet, a route with the lowest cost is selected from the routes from the own station to the base station 10, and the next station in the route is selected as the parent node. Then, the path cost of the route passing through the parent node is obtained, and the path cost is set as the path cost of the own station.

  For example, FIG. 11 is an explanatory diagram for explaining the derivation of the path cost from the mobile station 20-4 to the base station 10. As shown in FIG. 11, the mobile stations 20-1, 20-2, 20-3, 20-5, and 20-6 are located around the mobile station 20-4. “2”, “4”, “3”, “4”, “6”. The link cost between the mobile station 20-4 and each mobile station 20-1, 20-2, 20-3, 20-5, 20-6 is “8”, “5”, “4”, “2” and “7” are derived. Accordingly, the costs when the mobile stations 20-1, 20-2, 20-3, 20-5, and 20-6 are set as transfer destinations are “10”, “9”, “7”, and “6”. , “13”, the mobile station 20-4 selects the transfer path of the mobile station 20-5 that is the minimum value.

  The beacon packet generation unit 1004 floods the beacon packet into which at least the path cost of the local station and the moving speed of the local station are inserted. Each mobile station 20 floods a beacon packet at a random time.

  By sequentially performing the above-described flooding of beacon packets, the link cost between stations can be updated sequentially even if each mobile station 20 moves suddenly or moves with rotation.

  Next, when each mobile station 20 performs data communication toward the base station 10, the transmission destination selection unit 1006 refers to the peripheral radio table 1011 and the cost from the own station to the base station 10 becomes the minimum value. A route is selected, the mobile station 20 next to the route is set as a parent node, and a data packet is transmitted to the parent node. That is, the transmission destination selection unit 1006 generates a data packet including the address of the parent node, and the transmission unit 1001 transmits the data packet.

(A-3) Effect of Embodiment As described above, according to this embodiment, each mobile station can simply use the network configuration in consideration of the moving speed and rotation of its own station, so Compared with the case where the received power value or the like is used, the probability of communication failure can be reduced. As a result, the data collection success rate can be increased.

(B) Other Embodiments Although various modified embodiments have been mentioned in the above-described embodiments, the present invention can be applied to the following modified embodiments.

  2, 4, 5, and 6 exemplarily illustrated in the above-described embodiment are examples, and depending on the position of the wireless device attached to the human body and the exercise environment (for example, indoor environment such as gymnasium, etc. on exercise). Since the received power characteristics, moving speed, rotation angle, etc. of the antenna are different, it is desirable to use information according to such motion characteristics.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 10 ... Base station, 20 (20-1-20-8) ... Mobile station,
DESCRIPTION OF SYMBOLS 200 ... Link evaluation apparatus, 1 ..., rotation angle generation frequency deriving part, 2 ... Received power fluctuation characteristic deriving part, 3 ... Communication failure rate estimating part, 4 ... Link cost deriving part,
DESCRIPTION OF SYMBOLS 1001 ... Transmission means, 1002 ... Reception means, 1003 ... Timer, 1004 ... Beacon packet generation means, 1005 ... Data generation means, 1006 ... Transmission destination selection means, 1007 ... Beacon reception means, 1008 ... Beacon management means, 1009 ... Data reception Means: 1010: Movement measuring means, 1011: Peripheral wireless device table, 1012: Link cost table, 1013: Position measuring means.

In order to solve the above-described problem, a wireless communication device according to a first aspect of the present invention includes: (1) a transmission / reception unit that transmits / receives a radio wave; and (2) a route generation packet from a radio signal received by the transmission / reception unit. (3) a movement measuring means for measuring the moving speed of the local station, and (4) referring to predetermined link cost information, and at least the radio wave at the time of receiving the path generating packet. Management means for deriving an evaluation value of the communication path between the transmission station of the route generation packet based on the received power value and the moving speed of the own station, and the link cost information includes at least the moving speed and the received power. The evaluation value is associated with each combination of values, and using the relative relationship between the moving speed and the rotation according to the motion characteristics, the occurrence probability of the rotating angle for each moving speed and the Change in received power value And having an evaluation value obtained by reflecting a probability density.

According to a third aspect of the present invention, there is provided a wireless communication program comprising: (1) a transmission / reception unit that transmits / receives a radio wave; and (2) a route generation packet that receives a route generation packet from a radio signal received by the transmission / reception unit. Receiving means; (3) movement measuring means for measuring the moving speed of the own station; and (4) referring to predetermined link cost information, at least the received power value of the radio wave at the time of receiving the route generation packet and the own station. The link cost information is at least for each combination of the movement speed and the received power value. The evaluation value is associated, and using the relative relationship between the movement speed and rotation according to the motion characteristics, the probability of occurrence of the rotation angle for each movement speed and the fluctuation of the received power value for each rotation angle And having an evaluation value obtained by reflecting the rate density.

According to a fourth aspect of the present invention, there is provided a wireless communication method in which (1) a transmission / reception unit receives a radio wave, and (2) a route generation packet reception unit receives a route generation packet from a radio signal received by the transmission / reception unit. (3) The movement measurement means measures the moving speed of the own station, and (4) the management means refers to predetermined link cost information, and at least the reception power value of the radio wave at the time of receiving the route generation packet And an evaluation value of the communication path between the transmission station of the route generation packet based on the mobile station's own mobile speed and the link cost information at least for each combination of the mobile speed and the received power value. Using the relative relationship between the movement speed and the rotation according to the motion characteristics, and the probability of occurrence of the rotation angle for each movement speed and the fluctuation probability density of the received power value for each rotation angle, Has an evaluation value obtained by reflecting It is characterized in.

Claims (10)

Transmitting and receiving means for transmitting and receiving wireless radio waves;
Route generation packet receiving means for receiving a route generation packet from a radio signal received by the transmission / reception means;
A movement measuring means for measuring the moving speed of the own station;
Refer to predetermined link cost information, and based on at least the received power value of the radio wave at the time of receiving the route generation packet and the moving speed of the local station, the communication path between the transmission source of the route generation packet and And a management means for deriving an evaluation value. The link cost information is
At least an evaluation value is associated with each combination of moving speed and received power value,
Using the relative relationship between the movement speed and rotation according to the movement characteristics, the evaluation value obtained by reflecting the occurrence probability of the rotation angle for each movement speed and the fluctuation probability density of the received power value for each rotation angle The wireless communication apparatus according to claim 1. The link cost information includes an evaluation value obtained by reflecting information on a communication failure rate for each received power value and a fluctuation probability density of the received power value for each rotation angle. Wireless communication device.   The management means corrects an evaluation value of a communication path between the transmitting stations according to a predetermined fading characteristic when the received power value is larger than a threshold value and the moving speed is larger than a threshold value. The wireless communication device according to claim 1. It further comprises a position measuring means for measuring position information,
A distance between the management unit and the transmission station based on the position information of the transmission station included in the received route generation packet and the position information obtained by the position measurement unit with respect to the received power value. The wireless communication apparatus according to claim 4, wherein the wireless communication apparatus corrects the received power value obtained from the following. The link cost information reflects the moving speed of the transmitting station, the moving speed of the own station, and the received power value.
The management unit derives an evaluation value of a communication path with the transmitting station based on a moving speed of the transmitting station included in the route generation packet received above. The wireless communication device according to any one of the above. Route information for managing the path information in which the path evaluation value of the transmitting station included in the path generation packet and the evaluation value of the communication path between the transmitting station derived by the management means are stored for each station Management means;
A route generation packet transmitting means for transmitting a route generation packet including at least the path evaluation value of the local station as a path evaluation value of the local station as a path evaluation value of the local station among routes to the fixed station in the path information The wireless communication apparatus according to claim 1, further comprising: In a wireless communication system configured to include a fixed station and a plurality of mobile stations,
Each said mobile station has a radio | wireless communication apparatus in any one of Claims 1-7, The radio | wireless communications system characterized by the above-mentioned. Computer
Transmitting and receiving means for transmitting and receiving wireless radio waves;
Route generation packet receiving means for receiving a route generation packet from a radio signal received by the transmission / reception means;
A movement measuring means for measuring the moving speed of the own station;
Refer to predetermined link cost information, and based on at least the received power value of the radio wave at the time of receiving the route generation packet and the moving speed of the local station, the communication path between the transmission source of the route generation packet and A wireless communication program that functions as a management means for deriving an evaluation value. The transmission / reception means receives radio waves,
The route generation packet receiving means receives the route generation packet from the radio signal received by the transmission / reception means,
The movement measuring means measures the moving speed of its own station,
The management means refers to predetermined link cost information, and based on at least the reception power value of the radio wave at the time of receiving the route generation packet and the moving speed of the local station, A wireless communication method characterized by deriving an evaluation value of a communication channel.

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