TW201729580A - Communication apparatus and communication method - Google Patents

Abstract

A message control unit (140) uses a random number to establish a waiting time period from a reception of a control message broadcast-transmitted for a communication path construction till a transmission of a response message in reply to the control message. A radio transmission/reception unit (120) receives the broadcast-transmitted control message and, upon a lapse of the waiting time period, established by the message control unit (140), from the reception of the control message, transmits the response message to the transmission source of the control message.

Description

Communication device and communication method

The present invention relates to techniques for controlling the transmission of response messages to control messages for communication path construction.

In a wireless mesh network composed of a plurality of wireless devices that wirelessly collect various types of automation information or various sensor information, a routing protocol RPL (Routing Protocol for Low Power and Lossy) is used. Networks).

The RPL is a routing protocol for using a low-power, low-resource terminal such as a wireless sensor for an unstable communication environment, and is standardized by the IETF RFC 6550 (Non-Patent Document 1).

The RPL is formed into a tree structure called DODAG (Destination Oriented Directed Acyclic Graph). Further, in the RPL, control messages called DIO (DODAG Information Object) and DIS (DODAG Information Solicitation) are used in the uplink path construction. In addition, in the RPL, a control message called DAO (Destination Advertisement Object) is used in the downlink path construction. Non-Patent Document 2 and Non-Patent Document 3 indicate that one of the topics of the RPL protocol is that as the number of nodes increases, the control message occupies the bandwidth of the wireless network, and the transmission rate of the application message may be due to channel busy or conflict. And lower.

[Advanced technical literature]

[Non-patent literature]

Non-Patent Document 1: "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks", IETF, RFC 6550, March, 2012.

Non-Patent Document 2: N. Accettura, et al, "Performance Analysis of the RPL Routing Protocol.", IEEE International Conference on Mechatronics, Istanbul, Turkey, April 13-15, 2011.

Non-Patent Document 3: K. Heurtefeux and H. Menouar, "Experimental evaluation of a routing protocol for wireless sensor networks: RPL under study", IEEE Wireless and Mobile Networking Conference, 2013 6th Joint IFIP, 2013.

Non-Patent Document 1 discloses that in a conventional wireless mesh network using RPL, in the case where there are a plurality of terminals in the same coverage area, the control message increases the density of the wireless message traffic, resulting in application data. delay.

When there are a plurality of terminals, like the RPL, when the control message for constructing the communication path is sent by broadcast, the response message to the control message is simultaneously sent from the plurality of terminals. As a result, the flow of messages in response to messages has skyrocketed, causing problems that hinder the use of data communications.

The main object of the present invention is to solve the above problems, and its main purpose is to avoid the hindrance of application data communication due to the transmission of response messages to control messages.

The communication device of the present invention includes: a message control unit that uses a random number setting to start from a control message for constructing a communication path for broadcast transmission, a waiting time for transmitting a response message to the control message; and a message communication unit Receiving the control message transmitted by the broadcast, and transmitting the response message to the transmitting end of the control message when the waiting time set by the message control unit is received from receiving the control message.

In the present invention, the random number is used to set the waiting time from the reception of the control message to the transmission of the response message, and when the waiting time has elapsed since the reception of the control message, the response message is transmitted to the transmitting end of the control message. Therefore, a large number of response messages are not transmitted at the same time, and it is possible to prevent the communication of the application data from being blocked due to the transmission of the response message.

100‧‧‧Female communication station device

110‧‧‧Antenna

120‧‧‧Wireless Transceiver

130‧‧‧Signal Processing Department

140‧‧‧Information Control Department

150‧‧‧Time Management Department

160‧‧‧Path Management Department

170‧‧‧ Peripheral terminal information storage department

180‧‧‧Path Information Storage Department

190‧‧‧State Management Department

200‧‧‧Subcommunication station device

220‧‧‧RF circuit

230‧‧‧PHY Control Circuit

240‧‧‧CPU

250‧‧‧ oscillator

260‧‧‧RAM

270‧‧‧Auxiliary memory device

Fig. 1 is a view showing an example of a communication path construction program between the mother station device and the sub-communication station device in the first embodiment.

Fig. 2 is a view showing an example of a communication path construction program between the mother station device and the child communication station device in the first embodiment.

Fig. 3 is a view showing an example of a functional configuration of a mother station device and a sub-communication station device according to the first embodiment.

Fig. 4 is a view showing an example of the hardware configuration of the mother station device and the sub-communication station device according to the first embodiment.

Figure 5 is a diagram showing the communication path construction of the mother station device of the first embodiment. A flow chart of the operation example at the time.

Fig. 6 is a flow chart showing an operation example at the time of constructing a communication path of the sub-communication station device of the first embodiment.

Fig. 7 is a flowchart showing an operation example of the communication path construction of the sub-communication station device of the first embodiment.

Fig. 8 is a flow chart showing an operation example of the path joining completion program of the sub-communication station device of the first embodiment.

Fig. 9 is a view showing an example of a communication sequence between the mother station device and the sub-communication station device of the first embodiment.

Fig. 10 is a view showing an example of the functional configuration of the sub-communication station device of the second embodiment.

Fig. 11 is a flow chart showing an example of the operation of the sub-communication station apparatus of the second embodiment when counting the received message.

Fig. 12 is a flow chart showing an example of the operation of the path joining completion program of the sub-communication station device of the second embodiment.

Fig. 13 is a view showing an example of a timer value determination table in the second embodiment.

Embodiment 1

[constitution description]

Fig. 1 shows a mother station device 100 and a sub-communication station device 200 included in a communication system according to the present embodiment. In addition, FIG. 1 shows a construction procedure of a communication path executed between the parent communication station device 100 and the sub-communication station device 200. Figure 1 shows an example of two sub-communication station devices 200.

The mother station device 100 is a computer that manages the child station device 200. another In addition, the sub-communication station device 200 is a computer managed by the parent communication station device 100.

The mother station device 100 and the sub-communication station device 200 constitute, for example, a star network centered on the mother station device 100. Further, the mother station device 100 and the sub-communication station device 200 may also constitute a tree-like network. That is, it is possible to constitute a tree-like network as will be described later: the mother communication station device 100 is the highest level, and one of the sub-communication station devices 200 is an intermediate level, and the other of the sub-communication station devices 200 A sub-communication station device 200 is the lowest level.

In the star network, the communication path of the application data sent from each sub-communication station device 200 to the parent communication device 100 is referred to as an uplink communication path, and the application from the parent communication device 100 to each sub-communication device 200 is applied. The communication path of the data is called the downlink communication path.

Further, in the tree-like network, the communication path of the application data transmitted from the sub-communication station device 200 of the lowest level to the parent communication device 100 of the highest level via the intermediate-level sub-communication device 200 is called Uplink communication path. Further, the communication path of the application data transmitted from the parent station device 100 of the uppermost hierarchy to the child communication device 200 of the lowest level via the intermediate communication station device 200 is referred to as a downlink communication path.

In addition, in the following, the uplink communication path is also referred to as an uplink path, and the downlink communication path is also referred to as a downlink path.

Further, each sub-communication station device 200 corresponds to an example of a communication device. Further, the operation performed by each sub-communication station device 200 corresponds to an example of a communication method.

The communication path construction program between the mother station device 100 and the child communication station device 200 is the program shown in Fig. 1 and the program shown in Fig. 2.

In Figure 1 and Figure 2, the communication path construction in the star network is displayed. program.

In the communication path construction program of Fig. 1, the parent communication station device 100 broadcasts the uplink path notification first. Then, each of the sub-communication station apparatuses 200 that have received the uplink route notification transmits a downlink route notification to the parent station apparatus 100. Thereby, an uplink communication path and a downlink communication path are constructed between the mother communication station device 100 and each of the sub-communication station devices 200.

In the communication path construction program of Fig. 2, each sub-communication station device 200 first broadcasts an uplink path information request. Then, the parent station apparatus 100 that has received the uplink path information request broadcasts the uplink path notification. Then, each of the sub-communication station apparatuses 200 that have received the uplink route notification transmits a downlink route notification to the parent station apparatus 100. Thereby, an uplink communication path and a downlink communication path are constructed between the mother communication station device 100 and each of the sub-communication station devices 200.

The uplink path notification is a control message for constructing a downlink communication path. That is, the uplink path notification is to notify the surrounding other station device control information of the fact that the parent station device 100 or the child communication station device 200 has completed the communication path construction. Further, the uplink path notification is that the lower communication station device for the parent station device 100 or the child communication station device 200 recognizes the control message of the candidate uplink path.

The downlink path notification is a response message for the uplink path notification. That is, the downlink path notification is to notify the child communication station device 200 to join the control message of the downlink path of the upper communication station device at the transmitting end of the uplink path notification.

The uplink path information request is a control message for constructing an uplink communication path. That is, the uplink path information request is for the sub-communication station device 200 to search for the control message of the upper communication station device of its own communication station, in order to request its own communication station. The bit station device transmits a control message for the uplink path notification.

For example, in Non-Patent Document 1, the uplink path notification is called DIO, the downlink path notification is called DAO, and the uplink path information is called DIS.

Hereinafter, when it is not necessary to distinguish the uplink path notification, the downlink path notification, and the uplink path information request, these notifications are collectively referred to as control messages.

In addition, the uplink path notification corresponds to an example of the first control message, and the uplink path information request corresponds to an example of the second control message.

In the communication path construction program of the first embodiment and the second embodiment, the transmission time point when the sub-line station device 200 that has received the uplink route notification transmits the downlink route notification to the parent communication device 100 Decentralized, while avoiding a large number of downstream path notifications being transmitted at the same time.

In addition, in a tree-like network, a combination of (1) and (3), a combination of (1) and (4), a combination of (2) and (3), (2) and (a combination) will be described later. Any combination of 4) to construct a communication path.

(1) The mother station device 100 transmits an uplink path notification by broadcast. Then, the child communication station device 200 (the sub-communication station device 200 as the intermediate layer) that has received one of the uplink route notifications transmits a downlink route notification to the parent station device 100. Thereby, an uplink communication path and a downlink communication path are constructed between the mother communication station device 100 and the intermediate communication sub-interface device 200.

(2) One of the sub-communication station devices 200 (as the intermediate-level sub-communication station device 200) first transmits an uplink route information request by broadcast. Next, the mother station device 100 that has received the uplink path information request transmits the uplink path notification by broadcast. Then, the child communication station device 200 that has received one of the uplink route notifications transmits a downlink route notification to the parent communication device 100. In this way, in the mother communication station An uplink communication channel and a downlink communication path are constructed between the set 100 and the intermediate communication station device 200.

(3) One of the child communication station devices 200 (the sub-communication station device 200 as the intermediate layer) transmits the uplink route notification by broadcast. Then, the other sub-communication station device 200 (which is the lower-level sub-communication station device 200) that has received the uplink route notification transmits a downlink route notification to one of the child communication station devices 200. Thereby, an uplink communication path and a downlink communication path are constructed between the sub-communication station device 200 of the intermediate hierarchy and the sub-communication station device 200 of the lowermost hierarchy.

(4) The other child communication station device 200 (which is the sub-communication station device 200 of the lowest level) transmits the uplink route information request by broadcast. Then, the sub-communication station device 200 (as the intermediate-line sub-communication station device 200) that has received one of the uplink route information requests transmits the uplink route notification by broadcast. Then, the other sub-communication station device 200 that has received the uplink route notification transmits a downlink route notification to one of the child communication station devices 200. Thereby, an uplink communication path and a downlink communication path are constructed between the sub-communication station device 200 of the intermediate hierarchy and the sub-communication station device 200 of the lowermost hierarchy.

Fig. 3 shows an example of the functional configuration of the mother station device 100 and the sub-communication station device 200 of the present embodiment.

In the present embodiment, the mother station device 100 and the sub-communication station device 200 have the same functional configuration.

In Fig. 3, the antenna 110 is an antenna for implementing wireless communication.

The wireless transceiver unit 120 modulates the control message converted by the signal processing unit 130, which will be described later, and transmits the modulated signal through the antenna 110. In addition, wireless The transceiver unit 120 receives the modulation signal of the control signal through the antenna 110, and demodulates the modulation signal.

More specifically, the wireless transceiver unit 120 of the mother station device 100 transmits the modulation signal of the uplink path notification. In addition, the wireless transceiver unit 120 of the mother station device 100 receives the modulation signal of the downlink path notification or the modulation signal required by the uplink path information. In addition, the wireless transceiver unit 120 of the mother station device 100 transmits the modulation signal of the application data and receives the modulation signal of the application data.

Further, the radio transmission/reception unit 120 of the sub-communication station device 200 transmits the modulation signal of the downlink path notification or the modulation signal required for the uplink path information. Further, the radio transmission/reception unit 120 of the sub-communication station device 200 receives the modulation signal of the uplink path notification. Furthermore, the wireless transceiver unit 120 of the sub-communication station device 200 transmits the modulation signal of the application data and receives the modulation signal of the application data.

The wireless transmission/reception unit 120 of the sub-communication station device 200 corresponds to an example of a message communication unit.

The signal processing unit 130 converts the control message generated by the message control unit 140, which will be described later, into a signal that can be modulated by the wireless transmission/reception unit 120. Further, the signal processing unit 130 converts the signal demodulated by the wireless transmission/reception unit 120 into a control message that can be processed by the message control unit 140.

The message control unit 140 identifies the type of the received data, and if the received data is the application data destined for the own communication station, it is transferred to the external device. Further, the message control unit 140 performs processing for the type of the control message if the received data is a control message destined for the own communication station.

More specifically, the message control unit 140 of the mother station device 100 generates an uplink route notification when receiving the uplink route information request. In addition, When the message control unit 140 of the mother station device 100 receives the downlink route notification, the route management unit 160, which will be described later, updates the downlink route list.

Further, when receiving the uplink route notification, the message control unit 140 of the child communication station device 200 sets the waiting time from the reception of the uplink route notification to the transmission of the downlink route notification using the random number. Further, the message control unit 140 of the sub-communication station device 200 generates a downlink route notification when the waiting time has elapsed since the reception of the uplink route notification. Therefore, the wireless transmission/reception unit 120 of the sub-communication station device 200 transmits the downlink route notification to the parent communication station device 100 when the waiting time has elapsed since the transmission of the modulation signal notified by the uplink route. Further, when receiving the response signal to the downlink route notification, the message control unit 140 of the child communication station device 200 causes the path management unit 160, which will be described later, to update the uplink route list. Further, when the message control unit 140 of the sub-communication station device 200 receives the uplink route information request and the higher-level communication station device of the child communication station device 200 that is the transmission terminal of the uplink route information request, the uplink path is generated. Notice. Further, when receiving the downlink route notification, the message control unit 140 of the child communication station device 200 causes the route management unit 160 to update the downlink route list.

The time management unit 150 manages the time. The message control unit 140 uses the time information generated by the time management unit 150 to control the time point at which the control message is transmitted.

The path management unit 160 manages the transfer destination of the control message.

More specifically, the route management unit 160 of the parent station apparatus 100 registers the transmission end of the downlink route notification in the route information storage unit 180 as a communication destination in the downlink communication path.

Further, the path management unit 160 of the sub-communication station device 200 will uplink the path. The transmitting end of the notification is registered in the path information storage unit 180 as a communication destination in the uplink communication path. Further, the path management unit 160 of the sub-communication station device 200 registers the transmission end of the downlink route notification in the route information storage unit 180 as a communication destination in the downlink communication path.

The route information storage unit 180 memorizes the communication destination of the uplink communication path or the communication destination of the downlink communication path.

More specifically, the route information storage unit 180 of the mother station device 100 memorizes the communication destination in the downlink communication path.

Further, the path management unit 160 of the sub-communication station device 200 stores the communication destination of the uplink communication path. Further, the path management unit 160 of the sub-communication station device 200 included in the intermediate layer of the tree-shaped network memorizes the communication destination of the downlink communication path.

The state management unit 190 manages the state in which the communication station itself is in the state of constructing the communication path or the state in which the communication path is constructed.

Fig. 4 is a view showing an example of the hardware configuration of the mother station device 100 and the sub-communication station device 200 of the first embodiment.

As shown in FIG. 4, the mother station device 100 and the sub-communication station device 200 are configured by the following: an antenna 110, an RF (Radio Frequency) circuit 220, a PHY control circuit 230, a CPU (Central Processing Unit) 240, an oscillator 250, RAM (Random Access Memory) 260 and auxiliary memory device 270.

The antenna 110 is the same as that shown in FIG. The RF circuit 220 is a circuit that performs wireless communication. The PHY control circuit 230 is a circuit that performs control of the PHY layer. The CPU 240 is a processor that executes programs. The oscillator 250 is a circuit that generates a clock. RAM 260 is a volatile memory element. The auxiliary memory device 270 is an HDD (Hard) Non-volatile memory components such as Disk Drive) and flash memory.

The wireless transceiver unit 120 is implemented by the RF circuit 220. The signal processing unit 130 is implemented by the PHY control circuit 230. The time management unit 150 is realized by the oscillator 250. The peripheral terminal information storage unit 170 and the path information storage unit 180 are realized by the RAM 260 or the auxiliary storage device 270. The message control unit 140, the state management unit 190, and the path management unit 160 are realized by the CPU 240 executing a program.

That is, the CPU 240 executes a program that realizes the functions of the message control unit 140, the state management unit 190, and the path management unit 160. The program for realizing the functions of the message control unit 140, the state management unit 190, and the path management unit 160 is stored in the auxiliary storage device 270. Further, the program that realizes the functions of the message control unit 140, the state management unit 190, and the path management unit 160 is loaded into the RAM 260 at the time of execution, and is executed by the CPU 240.

Action description

First, an operation example of the mother communication station device 100 when the communication path is constructed will be described using FIG.

In the mother communication station device 100, wireless communication can be performed by wireless activation (step S100).

After the wireless activation, the message control unit 140 activates the uplink route notification timer using the time management unit 150 (step S110). The uplink path notification timer is a timer for adjusting the time point at which the uplink path notification is transmitted.

When the uplink route information request has been received before the uplink route notification timer expires (YES in step S120), the message control unit 140 uses the time management unit 150 to notify the uplink route of the standby timer (step S160). The uplink path notification standby timer is, before the uplink path notification timer expires When receiving the uplink path information request, the timer for adjusting the time point of transmitting the uplink path notification.

On the other hand, if the uplink route information request has not been received before the uplink route notification timer expires (YES in step S130), the message control unit 140 generates an uplink route notification, and transmits and receives the signal via the signal processing unit 130. The unit 120 and the antenna 110 transmit an uplink path notification by broadcast (step S180).

Further, after transmitting the uplink route notification, the message control unit 140 initializes the uplink route notification timer (step S190). Further, the initialization method uses, for example, a trickle timer described in Non-Patent Document 1.

When the downlink route notification has been received (YES in step S140), the route management unit 160 updates the downlink route list (step S150). Specifically, the message control unit 140 identifies the transfer destination that has received the next line path notification. Then, when the transmission destination of the downlink route notification is its own communication station, the message control unit 140 notifies the route management unit 160 of the transmission end of the downlink route notification. The route management unit 160 registers the transmission end of the downlink route notification in the route information storage unit 180 as a communication destination in the downlink communication path.

On the other hand, if the downlink route notification is not received in step S140, the message control unit 140 waits for the reception of the uplink route information request or the downlink route notification until the uplink route notification timer expires (steps S120 to S140).

Next, an operation example of the sub-communication station device 200 of the present embodiment when the communication path is constructed will be described using FIG. 6, FIG. 7, and FIG.

In the child communication station device 200, wireless communication can be performed by wireless activation (step S200).

After the wireless activation, the message control unit 140 activates the uplink route information request timer and the uplink route notification timer using the time management unit 150 (steps S201 and S202).

The uplink path notification timer is as described above. The uplink path information request timer is a timer for adjusting the time point at which the uplink path information request is transmitted.

When the uplink route information request has been received before the uplink notification timer expires (YES in step S203), the downlink route joining completion procedure of step S204 is executed. Hereinafter, the details of the downlink path joining completion procedure will be explained with reference to FIG.

When the uplink route information request timer expires in step S205, the message control unit 140 generates an uplink route information request, and transmits the uplink route information request via the signal processing unit 130, the wireless transceiver unit 120, and the antenna 110 (step S206).

Steps S207 to S214 are the same as the operations of steps S120 to S190 of the mother station device 100. Therefore, the description of steps S207 to S214 is omitted.

Next, with reference to Fig. 8, the details of the line path addition completion procedure in step S204 of Fig. 6 will be described.

After receiving the uplink route notification (step S300), in step S310, the message control unit 140 determines the number of waiting slots (N_wait) of the downlink route notification. The number of slots (N_wait) is an integer. For example, the message control unit 140 determines the number of waiting slots (N_wait) using a uniformly distributed random number between 1 and N_wait_max for a predetermined maximum number of slots N_wait_max.

In step S320, the message control unit 140 activates the downlink route notification timer using the time management unit 150. The downlink path notification timer is a timer for adjusting the time point at which the downlink path notification is transmitted.

For example, the message control unit 140 sets the time slot time set in advance. (T_wait), multiply the number of waiting slots (N_wait) determined in step S310, and set the time of the product value (T_wait×N_wait) to the timer expiration time. In other words, the message control unit 140 sets the waiting time from the reception of the uplink route notification to the transmission of the downlink route notification using the random number.

In step S330, the message control unit 140 stands by until the downlink path notification timer expires. During the period of step S330, the message control unit 140 may sleep or may perform an operation that is not related to the operation flow of FIG.

When the downlink route notification timer expires, the message control unit 140 generates a downlink route notification in step S340, and transmits a downlink route notification via the signal processing unit 130, the wireless transmission/reception unit 120, and the antenna 110 to the transmission end of the uplink route notification.

In step S350, when the response signal to the downlink route notification is received within a certain period of time after the downlink route notification is transmitted, the path management unit 160 updates the uplink route list (step S1360). Specifically, the path management unit 160 registers the transmission end of the response signal (that is, the transmission end of the uplink path notification) in the path information storage unit 180 as a communication destination in the uplink communication path.

In addition, the response signal can be any signal, for example, an ACK of the MAC (Media Access Control) layer.

Further, in step S350, if it is not possible to receive the response signal within a certain period of time after the transmission of the downlink route notification, the process returns to step S310.

Fig. 9 shows an example of the communication sequence between the mother station device 100 and the child communication station device 200 of the present embodiment. In Fig. 9, the mother station #1 corresponds to the mother station device 100. Further, the sub-communication station device 200 has sub-communication station #1, sub-communication station #2, and sub-communication station #3.

In addition, in Fig. 9, the mother communication station #1, the sub communication station #1, the sub communication station #2, sub-communication station #3 shows an example of the communication sequence when constructing a star-shaped communication path.

After the mother communication station #1 is wirelessly started in FIG. 9, the uplink path notification timer expires in the parent communication station #1, and the uplink path notification is broadcast from the parent communication station #1.

The sub-communication station #1, the sub-communication station #2, and the sub-communication station #3 respectively receive the uplink path notification, and start the downlink path notification timer. In order to allow the sub-communication station #1, the sub-communication station #2, and the sub-communication station #3 to determine the waiting time using the random number, the time at which the downlink path notification timer expires is different.

In the example of Fig. 9, the downlink path notification timer of the sub-communication station #1 expires first. Then, the downlink path notification timer of the sub-communication station #2 expires. Finally, the downstream path notification timer of sub-communication station #3 expires.

As described above, in the present embodiment, the number of random numbers is used, whereby the transmission timing of the downlink route notification of each sub-communication station can be shifted.

In addition, in the ninth figure, in order to simplify the description, only the expiration of the uplink path notification timer and the transmission of the uplink path notification immediately after the wireless start of the parent communication station #1 are illustrated, but in the parent communication station # In 1st, as shown in FIG. 5, the uplink path notification timer is repeatedly started, and the uplink path notification is repeatedly broadcasted.

Further, in each of the sub-communications stations, as shown in FIGS. 6 to 8, the uplink path notification timer is repeatedly activated, and the uplink route notification is repeatedly broadcasted, but the illustration is omitted for simplification of explanation.

Further, in Fig. 9, each sub-communication station receives the uplink route notification transmitted from the communication station #1 before transmitting the uplink route information request, and thus the transmission of the uplink route information request is not shown. As shown in Figure 6 to Figure 8, each sub-communication station is not connected. When the uplink route notification from the parent station #1 is received, the uplink path information request is broadcasted.

Description of the effect of the embodiment

As described above, according to the present embodiment, the case where the plurality of sub-communication station devices simultaneously transmit the downlink route notification does not occur. Therefore, it is possible to avoid the occurrence of communication of the application data due to the transmission of the downlink path notification.

Embodiment 2

In the first embodiment, each sub-communication station device determines the transmission time point of the downlink route notification based on the predetermined time slot time (T_wait) and the number of waiting time slots (N_wait) determined based on the number of random numbers.

In the second embodiment, each sub-communication station device estimates the number of sub-communication station devices existing around each sub-communication station device, and determines the downlink route notification based on the estimated number of sub-communication station devices and the number of random sub-communication device devices. Transfer time point.

Composition description

Fig. 10 shows an example of the functional configuration of the sub-communication station device 200 of the present embodiment. The peripheral terminal information storage unit 170 is added to the tenth figure in comparison with the functional configuration example of FIG.

The peripheral terminal information storage unit 170 memorizes the number of received messages to grasp the number of sub-communication station devices 200 existing in the vicinity.

The functional configuration of the mother station device 100 of the present embodiment is the same as that shown in Fig. 3.

The hardware configuration of the mother station device 100 and the sub-communication station device 200 of the present embodiment is the same as that shown in Fig. 4.

The differences between the first embodiment and the first embodiment will be mainly described below. Unspecified items below The same as in the first embodiment.

Action description

The operation procedure of the mother station device 100 is the same as that shown in Fig. 5.

Fig. 11 shows an operation example of the sub-communication station device 200 of the present embodiment.

In the present embodiment, the sub-communication station device 200 measures the received power and the message control every time the uplink route notification and the uplink route information request are received in steps S203 and S207 of FIG. 6 (step S400). The unit 140 compares the measured received power with a predetermined value (step S401). When the measured received power is equal to or greater than the threshold, the message control unit 140 increments the number of received messages of the peripheral terminal information storage unit 170. In other words, when the received power is equal to or greater than the threshold value, the message control unit 140 estimates that there are other sub-communication station devices 200 in the vicinity thereof, and causes the peripheral terminal information storage unit 170 to memorize the estimated number of the sub-communication station devices 200 in the vicinity.

Further, although the message control unit 140 estimates the number of the surrounding sub-communication station devices 200 using the received power, the number of the surrounding sub-communication station devices 200 may be estimated using other parameters.

Further, the message control unit 140 may perform the same operation not only when receiving the uplink route notification or the uplink route information request but also when receiving the application profile, and estimating the number of the surrounding sub-communication station devices 200.

Fig. 12 is a diagram showing an operation example after the uplink route notification is received in the sub-communication station device 200 of the present embodiment.

In Fig. 12, compared with the operation flow of Fig. 8, only step S510 is different, and S300 and S320 to S360 are the same. Only step S510 will be described below.

In step S510, the message control unit 140 determines the setting of the downlink path notification timing from among the candidate timer values described in the timer value determination table of FIG. 13 in response to the number of received messages stored in the peripheral terminal information storage unit 170. Timer value. In the timer value determination table of Fig. 13, the candidate timer value is defined for the range of the number of received messages. For example, if the number of received messages stored in the peripheral terminal information storage unit 170 is in the range of "0 to N1", the message control unit 140 selects any candidate timer value from among the candidate timer values "T0 to T100". Timer value. Further, the "T0 to T100" and the "T101 to T200" of the candidate timer value may be sequential values or may be random values. Each sub-communication station device independently selects a random number from among the candidate timer values.

Further, the message control unit 140 sets the value selected in step S510 to the downlink route notification timer.

Furthermore, in the timer value determination table of FIG. 13, a specific time (seconds) is defined as the candidate timer value, but the number of slots (N_wait) may be defined as the candidate timing for the range of the number of received messages. Value. In this case, the message control unit 140 multiplies the number of time slots (N_wait) selected from the timer value determination table by the time slot time (T_wait) as in the first embodiment, and sets the product value to the downlink path notification timing. Device.

Description of the effect of the embodiment

In the second embodiment, the transmission waiting time of the downlink route notification is determined in accordance with the number of the sub-communication station devices in the vicinity. Therefore, in addition to the effects of the first embodiment, it is possible to reduce the unnecessary long-term waiting for the transmission of the downlink route notification. The situation happened.

The above has been described with respect to the embodiments of the present invention, but it is also possible The above two embodiments are combined and implemented.

Alternatively, a part of one of the above two embodiments may be implemented.

Alternatively, portions of the above two embodiments may be combined and implemented.

Furthermore, the present invention is not limited to the above embodiment, and various modifications can be made as needed.

[Description of hardware composition]

Finally, the hardware composition is added.

The OS (Operating System) is stored in the auxiliary memory device 270. Moreover, at least a portion of the OS is executed by the CPU 240.

The CPU 240 executes an OS to perform task management, memory management, file management, communication control, and the like.

Although one CPU 240 is illustrated in FIG. 4, the parent station device 100 or the sub-communication station device 200 may include a plurality of CPUs 240.

Further, information, data, signal values, or variable values of the processing results of the display message control unit 140, the state management unit 190, and the path management unit 160 (hereinafter collectively referred to as "parts") are stored in the RAM 260, the auxiliary storage device 270, or In the scratchpad or cache memory in the CPU 240.

In addition, programs that implement the functions of "parts" can also be stored in removable memory such as disks, floppy disks, compact discs, CDs, Blu-ray (trademark) disks, and DVDs.

In addition, "part" can also be replaced by "circuit", "step", "program", or "processing".

Further, the mother station device 100 and the sub-communication station device 200 can be implemented by a logic IC (Integrated Circuit), a GA (Gate Array), or an ASIC (Application). Circuit implementation such as Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

In this case, the "parts" are implemented as part of the circuit, respectively.

Furthermore, the CPU 240 and the above-described circuits may be collectively referred to as processing circuits.

100‧‧‧Female communication station device

110‧‧‧Antenna

120‧‧‧Wireless Transceiver

130‧‧‧Signal Processing Department

140‧‧‧Information Control Department

150‧‧‧Time Management Department

160‧‧‧Path Management Department

180‧‧‧Path Information Storage Department

190‧‧‧State Management Department

200‧‧‧Subcommunication station device

Claims (8)

A communication device comprising: a message control unit that uses a random number setting to wait for a waiting time from receiving a control message for constructing a communication path for broadcast transmission to transmitting a response message for the control message; and a message communication unit, Receiving the control message transmitted by the broadcast, and transmitting the response message to the transmitting end of the control message when the waiting time set by the message control unit has passed since the receiving of the control message. The communication device according to claim 1, wherein the message control unit starts from the first control message that receives the control message for constructing the communication path for the downlink transmission using the random number setting, and transmits the message to the Waiting time until the response message of the first control message; the message communication unit receives the first control message transmitted by the broadcast, and when the waiting time set by the message control unit is received after receiving the first control message, The response message is transmitted to the transmitting end of the first control message. The communication device according to claim 2, wherein the message control unit sets the waiting time when the message communication unit has received the first control message; and the message communication unit receives the first control When the message passes the waiting time set by the message control unit, the response message is transmitted to the transmitting end of the first control message. The communication device according to claim 2, wherein the communication device further includes a path management unit that registers the transmission end of the first control message as a communication destination in the uplink communication path. The communication device according to claim 2, wherein the message communication unit transmits the second control message of the control message for constructing the uplink communication path by broadcasting when the first control message is not received. The receiving end of the second control message returns the second control message and broadcasts the transmitted first control message; the message control unit sets the waiting time when the message communication unit has received the first control message; the message The communication unit transmits the response message to the transmitting end of the first control message when the waiting time set by the message control unit is received from the reception of the first control message. The communication device according to claim 2, wherein the message communication unit transmits the first control message by broadcasting, and receives a response message for the first control message from the transmitting end of the first control message; The communication device further includes a path management unit that registers the transmitting end of the response message as a communication destination of the downlink communication path. The communication device according to claim 1, wherein the message control unit estimates the number of other communication devices in the vicinity of the communication device, and sets the waiting time using the estimated number of the other communication devices and the number of random devices. A communication method in which a computer uses a random number setting to start from a control message for constructing a communication path for broadcast transmission, and a waiting time for transmitting a response message to the control message; the computer receives the control message transmitted by the broadcast, Transmitting the response message to the control when the waiting time has elapsed since the receipt of the control message The transmitting end of the message.