JP7389250B2 - Wireless communication device, wireless communication method and program - Google Patents

Description

The present invention relates to a wireless communication device, a wireless communication method, and a program for performing multicast communication, and in particular, it is possible to select a modulation method according to the line condition of nodes on a multicast communication route and eliminate the influence of other communication stations. The present invention relates to a wireless communication device, a wireless communication method, and a program that can prevent communication errors and ensure communication quality.

[Description of prior art]
Conventionally, there are mobile networks using autonomous distributed access.
In such a mobile network, mobile communication stations autonomously detect terminals and autonomously optimize routes to construct a temporary wireless network (ad-hoc network). As a result, communication can be achieved while reducing the amount of delay and suppressing the load on the line.

Multicast communication is often used as a method of distributing information to reduce the load on lines. Multicast communication is a method for performing one-to-many communication, unlike conventional one-to-one (unicast) communication.
Multicast communication on a network uses multicast communication using an IP (Internet Protocol) protocol.

Ad hoc multicast routing is used to establish multicast communication on an ad hoc network. For ad hoc multicast routing, for example, a method described in Japanese Patent No. 5465328 (Patent Document 1) is used.

Further, since the ad hoc network is a wireless line, in each communication, target digital data is digitally modulated, frequency converted, and power amplified.
At this time, since the distance and propagation environment of wireless lines differ depending on the communication partner, it is necessary to select the optimal modulation method according to changes in line conditions.

For example, if the line is stable, it is preferable to use a modulation method that is prone to communication errors but can transmit multiple pieces of digital information on a single carrier wave, and if the line is unstable, use the opposite method. It is hoped that
For selecting the optimal modulation method, for example, there is a method described in Japanese Patent No. 5658954 (Patent Document 2).
This is a method that uses retransmission control information, etc., and is effective in one-to-one communication.

[Configuration of conventional communication device: Figure 6]
The configuration of a communication device that performs conventional multicast communication will be described using FIG. 6. FIG. 6 is a block diagram of a conventional communication device.
As shown in FIG. 6, the conventional communication device includes a network section 40, a radio access control section (MAC section) 50, and a radio signal processing/high frequency section 60.

The network unit 40 is a CPU (Central Processing Unit) and includes an ad hoc multicast routing unit 41 and a frame generation/analysis unit 42.
The ad hoc multicast routing unit 41 controls ad hoc multicast communication, performs routing control to construct an ad hoc network, and generates an ad hoc routing message (ad hoc message).
Further, the ad hoc multicast routing unit 41 stores information that associates transmission entries with IP addresses of child nodes serving as transmission destinations for each group of multicast communication.

The frame generation/analysis unit 42 attaches a MAC (Media Access Control) header to a transmitted IP packet or ad hoc message, generates a transmission MAC frame, and outputs it to the radio access control unit 50.
Further, when a received MAC frame is input from the radio access control unit 50, the frame generation/analysis unit 42 analyzes the frame, extracts an IP packet or an ad hoc message, outputs the IP packet to each unit as appropriate, and sends an ad hoc message. is output to the ad hoc multicast routing section 41.

The radio access control unit 50 includes an FCS (Frame Check Sequence)/transmission timing setting unit 51, a control frame analysis unit 52, a transmission timing control unit 53, an FCS/transmission timing analysis unit 54, and a unicast modulation method determination unit. 55.

The FCS/transmission timing setting unit 51 inserts an error detection code into the input transmission MAC frame.
Further, the FCS/transmission timing setting section 51 outputs the control frame to the control frame analysis section 52 and sets the transmission timing instructed by the control frame analysis section 52 in the transmission timing control section 53.
Furthermore, the FCS/transmission timing setting unit 51 attaches the modulation scheme set by the unicast modulation scheme determination unit 55 to the transmission MAC frame and outputs it to the transmission timing control unit 53.

The control frame analysis unit 52 analyzes the control frame of the transmission MAC frame, reads the transmission timing setting (predetermined timing or line idle state), and instructs the FCS/transmission timing setting unit 51.

The transmission timing control unit 53 detects the transmission timing according to the settings, and outputs the transmission MAC frame to the radio signal processing/high frequency unit 60 when the transmission timing comes.
Further, the FCS/transmission timing analysis unit 54 performs FCS processing on the received MAC frame to detect errors, and if there is an error, performs predetermined processing such as a retransmission request. is output to the network section 40.

The unicast modulation method determination unit 55 selects the optimal modulation method for unicast communication.
When the unicast modulation method determination unit 55 receives quality information (equalization error, etc.) upon receiving the MAC frame containing the MAC address of the communication target station from the radio signal processing/high frequency unit 60, the unicast modulation method determination unit 55 performs a The optimum modulation method for performing unicast communication with the transmission source is determined (determined) and set in the FCS/transmission timing setting unit 51.

The radio signal processing/high frequency unit 60 modulates the transmission MAC frame from the radio access control unit 50 using a specified modulation method, up-converts the frame, and wirelessly transmits the frame.
Furthermore, the radio signal processing/high frequency section 60 receives a radio signal, down-converts and demodulates it, and outputs a MAC frame to the radio access control section 50. At this time, the radio signal processing/high frequency section 60 calculates the communication quality such as the equalization error of the received signal and outputs it to the radio access control section 50.

[Adaptive modulation of conventional multicast communication: Figure 7]
Further, the unicast modulation method determining unit 55 adaptively selects a modulation method based on communication quality even in multicast communication.
Here, adaptive modulation in conventional multicast communication will be explained using FIG. 7. FIG. 7 is an explanatory diagram showing adaptive modulation in conventional multicast communication.

As shown in Figure 7, in an ad hoc network consisting of nodes A to F, when data is transmitted from node A to nodes C and F using multicast communication, nodes C and F are receiving nodes, and nodes B and E are relay nodes. Become.
Although node D is neither a relay node nor a receiving node, it sends and receives ad-hoc routing messages for network control in order to continue building a wireless link.

When node A selects a modulation method for transmission, the unicast modulation method determining unit 55 selects communication quality according to the node with the lowest quality among all adjacent nodes.
In the example of FIG. 7, the SNR (Signal to Noise Ratio) in communication with Node B is 12 dB, the SNR of Node E is 16 dB, but the SNR of Node D, which is unrelated to multicast communication, is 12 dB. It is 8.3dB.

Therefore, in the conventional communication device, node A selects a BPSK (Binary Phase Shift Keying) modulation method according to node D having the lowest SNR, and performs multicast communication using BPSK.
In other words, a method with a slower transmission speed than necessary is selected.

This is because in conventional communication devices, the modulation method is selected by the radio access control unit 50, which is the L2 (data link layer), and it is not possible to determine which nodes are relay nodes and receiving nodes. This is because processing is performed based on the communication quality in communication with all nodes within the area.

If an appropriate modulation method is not selected, transmission delays will occur during network connections using wireless lines and information sharing during network connections, and in the worst case, there will be a significant drop in communication quality, with transmission becoming impossible. It may lead to.

[Related technology]
Prior art related to communication devices include Japanese Patent No. 5465328 "Wireless Communication Device and Wireless Communication Method" (Patent Document 1) and Japanese Patent No. 5658954 "Wireless Communication Device" (Patent Document 2).

Patent Document 1 describes a wireless communication device capable of multicast transmission compatible with both wired networks and wireless networks that are interconnected.
Patent Document 2 describes a wireless communication device that can effectively select a modulation method and a coding rate in an adaptive modulation and coding method.

Patent No. 5465328 Patent No. 5658954

As mentioned above, in conventional communication devices, the modulation method is selected by the radio access control unit (L2), so the communication station on the multicast communication route that is actually waiting for reception cannot be identified, and the control The problem was that it was difficult to select an appropriate modulation method, and there was a risk of deterioration in communication quality.

Note that Patent Documents 1 and 2 do not describe that in multicast communication, selecting an appropriate modulation method that targets the communication quality of communication stations on the route and excludes the influence of other communication stations. .

The present invention was made in view of the above-mentioned circumstances, and targets communication stations that actually wait for reception in multicast communication, and selects an appropriate modulation method to eliminate the influence of other communication stations and improve communication quality. The purpose is to provide a communication device, a communication method, and a program that can secure communication.

In order to solve the problems of the conventional example described above, the present invention is a communication device that constructs a network using an ad-hoc multirouting protocol and performs multicast communication, which includes a network unit that controls multicast communication, and a network unit that controls transmission timing. The network unit stores the communication quality of a plurality of nodes acquired from the radio access control unit at the time of reception as node quality information, and when transmitting multicast communication , Determine the optimal route corresponding to the group, generate a list of receiving station and relay station nodes on the route, refer to node quality information, and determine the communication quality corresponding to the nodes included in the list. , the lowest value with the lowest quality is found, and the modulation method is selected based on the lowest value.

Further, in the above communication device, the present invention provides that the wireless access control unit outputs the received MAC frame and its reception quality to the network unit, and the network unit responds to the group of the multicast communication when transmitting the multicast communication. An ad hoc multicast routing unit that determines the optimal route and generates an IP address list indicating the IP addresses of receiving station and relay station nodes on the route, and reception quality of MAC frames input from the radio access control unit. and the combination of MAC address and IP address included in the MAC frame are stored as node quality information . When an IP address list is input, the node quality information is referred to and the input IP A quality information management unit that outputs the lowest value of reception quality corresponding to the IP address included in the address list, and an IP address list generated according to the group of multicast communication from the ad hoc multicast routing unit when transmitting multicast communication. and a multicast modulation method determining section that outputs the acquired IP address list to the quality information management section and selects a modulation method according to the lowest value of reception quality input from the quality information management section. It is a feature.

Further, the present invention is characterized in that the reception quality in the communication device is an equalization error or a signal-to-noise ratio.

Further, in the above communication device, the present invention provides an IP address-MAC address table in which the network unit obtains a combination of an IP address and a MAC address from a MAC frame of a received ad hoc message to generate an IP address-MAC address table. It is characterized in that it includes a holding section, and the quality information management section generates node quality information by referring to an IP address-MAC address table.

The present invention also provides a communication method in a communication device that constructs a network using an ad hoc multirouting protocol and performs multicast communication, in which the communication device uses the communication quality of a plurality of nodes acquired at the time of reception as node quality information. When transmitting multicast communication, it determines the optimal route corresponding to the group of multicast communication, generates a list of receiving stations and relay station nodes on the route, and refers to node quality information. , among the communication qualities corresponding to the nodes included in the list , the lowest value with the lowest quality is determined, and the modulation method is selected based on the lowest value.

The present invention also provides a program that operates in a communication device that constructs a network using an ad-hoc multirouting protocol and performs multicast communication, and the program operates in a communication device that performs multicast communication by transmitting node quality information to the communication device, which receives communication quality information of a plurality of nodes acquired at the time of receiving node quality information. When sending multicast communication , it determines the optimal route corresponding to the group of multicast communication, generates a list of receiving station and relay station nodes on the route, and refers to node quality information. The present invention is characterized in that the lowest value of the lowest quality among the communication qualities corresponding to the nodes included in the list is determined , and the modulation method is selected based on the lowest value.

According to the present invention, there is provided a communication device that constructs a network using an ad hoc multirouting protocol and performs multicast communication, and includes a network unit that controls multicast communication and a radio access control unit that controls transmission timing. Then, the network unit stores the communication quality of multiple nodes obtained from the radio access control unit at the time of reception as node quality information, and determines the optimal route corresponding to the group of multicast communication when transmitting multicast communication. A list of receiving stations and relay station nodes on the route is generated, and the lowest value of the communication quality corresponding to the nodes included in the list is determined by referring to the node quality information. Since the communication device selects the modulation method based on the lowest value, it is possible to identify the communication stations on the multicast communication route and select the appropriate modulation method for the communication stations actually on the route. This has the effect of preventing the influence of communication stations not on the route and ensuring good communication quality.

Further, according to the present invention, there is provided a communication method in a communication device that constructs a network using an ad hoc multi-routing protocol and performs multicast communication, wherein the communication device determines the communication quality of a plurality of nodes acquired at the time of reception as a node quality. It is stored as information, and when transmitting multicast communication, it determines the optimal route corresponding to the group of multicast communication, generates a list of receiving stations and relay station nodes on the route, and refers to node quality information. This communication method calculates the lowest value of the lowest quality among the communication qualities corresponding to the nodes included in the list , and selects the modulation method based on the lowest value, so communication stations on the multicast communication path can be identified. As a result, it is possible to select an appropriate modulation method for communication stations actually on the route, thereby preventing the influence of communication stations not on the route and ensuring good communication quality.

Further, according to the present invention, there is provided a program that operates in a communication device that constructs a network using an ad hoc multi-routing protocol and performs multicast communication, the program that executes the communication quality of a plurality of nodes acquired at the time of reception. It is stored as quality information, and when transmitting multicast communication, it determines the optimal route corresponding to the group of multicast communication, generates a list of receiving stations and relay station nodes on the route, and stores the node quality information. The program looks up the communication quality corresponding to the nodes included in the list and finds the lowest value with the lowest quality, and selects the modulation method based on the lowest value, so communication on the multicast communication path The effect is that it is possible to identify stations and select an appropriate modulation method for communication stations actually on the route, prevent the influence of communication stations that are not on the route, and ensure good communication quality. There is.

FIG. 2 is a configuration block diagram of the present communication device. FIG. 2 is an explanatory diagram showing an outline of the operation of the present communication device. FIG. 2 is an explanatory diagram showing the configuration of multicast group information. FIG. 2 is an explanatory diagram showing a sequence of frequency selection in the present communication device. FIG. 3 is an explanatory diagram of a modulation method selection table. FIG. 1 is a configuration block diagram of a conventional communication device. FIG. 2 is an explanatory diagram showing adaptive modulation in conventional multicast communication.

Embodiments of the present invention will be described with reference to the drawings.
[Overview of embodiment]
A communication device according to an embodiment of the present invention (this communication device) is a communication device that performs multicast communication, and in a network unit, upon reception, reception quality is stored as node quality information in correspondence with the IP address of a node. In advance, when transmitting multicast communication, refer to the node quality information and select the lowest value of the communication quality corresponding to the IP address of the node on the route specified by the group of multicast communication. The modulation method is selected based on the minimum value, which makes it possible to select an appropriate modulation method for communication stations on the actual multicast communication path, and eliminates the influence of communication stations not on the path. It is possible to exclude this to ensure good communication quality.

Further, the present communication method is a communication method in the present communication device, and the present program is a program that operates in the present communication device.

[Configuration of this communication device: Figure 1]
The configuration of this communication device will be explained using FIG. 1. FIG. 1 is a block diagram of the configuration of this communication device.
As shown in FIG. 1, the basic configuration of this communication device is the same as the conventional one, and includes a network unit 10, a wireless access control unit (MAC unit) 20, and a wireless signal processing/high frequency unit 30. There is.
The radio signal processing/high frequency section 30 is equivalent to the conventional radio signal processing/high frequency section 60 shown in FIG. 6, and detailed description thereof will be omitted.

In conventional communication devices, the selection of the modulation method at the time of transmission in multicast communication is performed by the wireless access control unit 50, which is the L2, but in this communication device, the selection of the modulation method during transmission is performed by the network unit 10, which is the L3.
As a result, this communication device can identify the communication stations on the route from among the communication stations in the area and select an appropriate modulation method based on the quality of communication with these communication stations. be.

[Overview of operation of this communication device: Figure 2]
Before explaining each part of this communication device, an overview of the operation of this communication device will be explained using FIG. 2. FIG. 2 is an explanatory diagram showing an outline of the operation of this communication device.
The network shown in FIG. 2 is equivalent to that shown in FIG. 7, and assumes a case where data is transmitted from node A to nodes C and F by multicast communication. The communication quality (SNR) between node A (this communication device) and each adjacent node is the same as in FIG. 7 .

Here, this communication device (node A) determines nodes B and E on the actual multicast communication route from among the nodes in the area, and adjusts the communication quality for communication with these nodes. Select the modulation method based on the
In other words, although node D is communicating to maintain the wireless link, it is not on the path of the multicast communication, so when determining the modulation method for the multicast communication, node A Quality is not reflected. That is, the modulation method for multicast communication is determined based on the communication quality of nodes on the route of multicast communication.

As a result, the lowest value of SNR is 12 dB, and node A selects QPSK (Quadrature Phase Shift Keying) for transmission of the multicast communication. As a result, the transmission speed can be increased compared to BPSK selected in the conventional communication device shown in FIG. 7, and it is possible to improve throughput and reduce delay during transmission.
This communication device selects a modulation method based on information (modulation method selection table) that associates communication quality and modulation method. The modulation method selection table will be described later.

Since the preamble is BPSK, node D also receives it, performs carrier sense, and waits for transmission according to the PLCP (Physical Layer Convergence Protocol) frame, or waits for transmission in a busy state where other communication stations are communicating. By doing so, it is possible to avoid signal collisions.

[Network section 10]
Returning to FIG. 1, the configuration of this communication device will be explained.
The network unit 10 includes a control unit such as a CPU, a storage unit, and an interface unit, and realizes various functions by the control unit starting a program stored in the storage unit.
The network unit 10 includes an ad hoc multicast routing unit 11, a frame generation/analysis unit 12, an IP address-MAC address table holding unit 13, a quality information management unit 14, and a multicast modulation unit 14, as units that implement specific functions. The system includes a system determination unit 15.

[Ad-hoc multicast routing section 11]
The ad hoc multicast routing unit 11 performs routing control of ad hoc multicast communication as in the past, and indicates the source IP address and destination IP address (multicast group address) of multicast communication, and information on receiving stations and relay stations. It manages combinations of child node IP address lists.
Then, at the time of multicast transmission, the optimum route corresponding to the multicast group is determined and a child node IP address list is generated.

A combination of a source IP address and a destination IP address (multicast group address) is called a multicast participation entry.
Furthermore, the combination of the multicast participation entry and the child node IP address list is referred to as multicast group information.
Although only one piece of multicast group information is shown in the figure, a plurality of pieces of multicast group information may be stored in the ad hoc multicast routing unit 11. Multicast group information will be described later.

Then, the ad hoc multicast routing unit 11 of the present communication device outputs a child node IP address list corresponding to the destination multicast group based on a request from the multicast modulation method determination unit 15, which will be described later.

[Frame generation/analysis unit 12]
The frame generation/analysis unit 12 generates a MAC frame for an IP packet or ad hoc message to be transmitted, and extracts the IP packet or ad hoc message from the received MAC frame, as in the conventional case.
As a feature of this communication device, when an IP packet transmitted by multicast communication (referred to as a multicast packet) is input, the frame generation/analysis unit 12 modulates the combination of the source IP address and destination IP address by multicasting. The modulation method is outputted to the method determining unit 15 to receive the designation of the modulation method.

Further, the frame generation/analysis unit 12 of the communication device attaches the modulation scheme designated by the multicast modulation scheme determination unit 15 to the MAC frame to be transmitted and outputs it to the radio access control unit 20.

[IP address-MAC address table holding unit 13]
The IP address-MAC address table holding unit 13 acquires the combination of the source IP address and MAC address from the ad-hoc routing message included in the received MAC frame, generates and stores an IP address-MAC address table. .

[Quality information management department 14]
The quality information management unit 14 determines and stores the communication quality for each node based on the received MAC frame, and outputs the lowest quality value among the communication qualities of the destination child nodes at the time of multicast transmission. It is something.
When acquiring reception quality, not only ad hoc messages but also unicast communication may be used.

Specifically, the quality information management unit 14 inputs the received MAC frame and communication quality information (equalization error, etc.) from the radio access control unit 20, and sets the quality information for each node (transmitting node in the received MAC frame). A MAC address, a node IP address corresponding to the MAC address, and equalization error information or SNR information calculated from the equalization error are stored as a set. This information is called node quality information.

Here, the quality information management unit 14 refers to the IP address-MAC address table to identify the node IP address corresponding to the node MAC address.
In other words, the quality information management unit 14 accumulates (updates) the node quality information each time the present communication device receives an ad hoc message.
Node quality information stores communication quality information of all nodes that communicate with the communication device, regardless of whether they are child nodes in multicast communication (or not on the route of multicast communication). It is.

Then, when the child node IP address list is input from the multicast modulation method determining unit 15, the quality information management unit 14 refers to the node quality information and sets the node IP address included in the input child node IP address list. Corresponding quality information (here, SNR information) is specified.
Furthermore, the quality information management section 14 identifies the lowest (worst quality) value from among the identified quality information, and outputs it to the multicast modulation method determination section 15 .

[Multicast modulation method determination unit 15]
The multicast modulation method determining section 15 selects an appropriate modulation method according to the communication quality with a child node serving as a destination or a relay station during multicast transmission, and specifies it to the frame generation/analysis section 12.

Specifically, when a combination of a source address and a destination IP address is input from the frame generation/analysis unit 12, the multicast modulation method determination unit 15 performs ad hoc multicast routing based on the source address and destination IP address. 11 for a child node IP address list.
Thereby, the multicast modulation method determining unit 15 obtains a child node IP address list corresponding to the group address to which data to be transmitted will be transmitted. That is, the IP addresses included in the child node IP address list are the IP addresses of nodes on the route of the multicast communication.

Further, the multicast modulation method determination unit 15 outputs the acquired child node IP address list to the quality information management unit 14, and acquires the lowest value of the quality information corresponding thereto.
Then, based on the lowest value of the quality information, a modulation method is selected by referring to an internally stored modulation method selection table, and the selected modulation method is output to the frame generation/analysis section 12.

Although not shown here, the network unit 10 of the communication device can select a modulation method not only for multicast communication but also for unicast communication.
In this case, during unicast communication, the frame generation/analysis unit 12 outputs the source IP address and destination MAC address extracted from the ad hoc message to the multicast modulation method determination unit 15.

The multicast modulation method determination section 15 queries the quality information management section 14 about the modulation method with the destination MAC address, and the quality information management section 14 sends the quality information corresponding to the destination MAC address to the multicast modulation method determination section 15. Output.
The multicast modulation method determining section 15 identifies a modulation method based on the input quality information and outputs it to the frame generation/analysis section 12.
In this way, the modulation method for unicast communication can also be appropriately selected based on communication quality.

In this communication device, the configuration of the wireless access control unit 20 is the same as the conventional one, but since the MAC frame input from the network unit 10 already has a modulation scheme specified, it is not selected by the unicast modulation scheme determination unit 25. The modulation method is set not to be adopted.

[Multicast group information: Figure 3]
Here, the structure of multicast group information will be explained using FIG. 3. FIG. 3 is an explanatory diagram showing the structure of multicast group information.
As shown in FIG. 3, the multicast group information has a configuration in which a source (own device) IP address 71, a destination IP address 72, and a plurality of child node IP addresses 73-1 to 73-n are concatenated.

The destination IP address is a group address that specifies a multicast communication group, and specifies a receiving node belonging to the group. The combination of the source IP address and destination IP address is a multicast participation entry.
The child node IP address list is a list in which a plurality of child node IP addresses 73-1 to 73-2 are linked. In the multicast communication, an appropriate route passing through these multiple child nodes is determined, so multiple child node addresses are on the route and serve as receiving stations or relay stations that wait for transmission signals from the device. This is the address of the child node.

[Sequence in this communication device: Figure 4]
Next, the frequency selection sequence in this communication device will be explained using FIG. 4. FIG. 4 is an explanatory diagram showing a frequency selection sequence in this communication device.
As shown in FIG. 4, when the received high frequency signal is input to the wireless signal processing/high frequency section 30 (S11), the wireless signal processing/high frequency section 30 down-converts it to a baseband signal, demodulates it, and performs MAC The frame is output to the wireless access control unit 20 (S12).
Also, at this time, the radio signal processing/high frequency section 30 calculates quality information such as equalization error, and outputs the quality information to the radio access control section 20 (S13).

The wireless access control unit 20 outputs the MAC frame to the frame generation/analysis unit 12 of the network unit 10 (S14).
Furthermore, as a feature of this communication device, the wireless access control unit 20 outputs the MAC frame to the IP address-MAC address table holding unit 13 and the quality information management unit 14 (S15, S16), and outputs quality information such as equalization error. is output to the quality information management section 14 (S17).

The frame generation/analysis unit 12 analyzes the MAC frame, outputs an ad hoc message to the ad hoc multicast routing unit 11, and appropriately outputs the IP packet to the display processing unit, audio output unit, etc. (S18).

The IP address-MAC address table holding unit 13 acquires correspondence information between IP addresses and MAC addresses from the input ad hoc message of the MAC frame, and registers the information in the IP address-MAC address table.

In addition, the quality information management unit 14 calculates the SNR from the input quality information such as the equalization error, and combines the MAC address included in the input MAC frame and the IP address included in the ad hoc message to determine the node quality. Store as information.
The quality information management unit 14 performs this process every time the communication device receives data, and accumulates and updates the node quality information. If the value is received multiple times from the same node, the latest value is stored.

On the other hand, during transmission, when an IP packet for multicast communication is input to the frame generation/analysis unit 12 (S21), the frame generation/analysis unit 12 extracts the destination IP address (multicast group address) corresponding to the multicast group. Then, the source address and destination IP address are output to the multicast modulation method determination unit 15 (S22).

The multicast modulation method determination unit 15 outputs the source address and destination IP address to the ad hoc multicast routing unit 11, and creates a multicast receiver node IP address list ( child node IP address list) (S23).
Then, the multicast modulation method determining unit 15 receives the child node IP address list from the ad hoc multicast routing unit 11 (S24), and sends the child node IP address list to the quality information management unit 14 (S25).

The quality information management unit 14 reads quality information (SNR) corresponding to the IP address included in the input child node IP address list from the stored node quality information, and performs multicast modulation on the minimum SNR value among them. It is output to the method determining unit 15 (S26).

The multicast modulation method determining unit 15 that has received the minimum SNR value refers to the modulation method selection table, selects the modulation method corresponding to the SNR value, and outputs it to the frame generation/analysis unit 12 (S27).

The frame generation/analysis unit 12 outputs the MAC frame of the multicast packet to be transmitted to the radio access control unit 20 (S28), and also outputs information specifying the modulation method of the MAC frame to the radio access control unit 20 (S29). ).

At a predetermined transmission timing, the wireless access control unit 20 outputs the information on the MAC frame and modulation method to the wireless signal processing/high frequency unit 30 (S31, S32), and the wireless signal processing/high frequency unit 30 receives the specified transmission timing. The signal is modulated using a modulation method, converted into a high frequency signal, and output wirelessly (S32).
This is how the sequence in this communication device is performed.

[Modulation method selection table: Figure 5]
Next, the modulation method selection table stored in the multicast modulation method determining section 15 will be explained using FIG. 5. FIG. 5 is an explanatory diagram of the modulation method selection table.
As shown in FIG. 5, in the modulation method selection table, a selected modulation method and a corresponding SNR threshold value are stored for each item number.
When the SNR value (minimum value) input from the quality information management unit 14 is less than each threshold value, the corresponding modulation method is selected.

For example, if the SNR value (minimum value) is less than 10 dB, BPSK is selected, and if it is 10 dB or more and less than 14 dB, QPSK is selected. Furthermore, if the SNR value is 14 dB or more and less than 20 dB, 16QAM is selected, and if the SNR value is 20 dB or more and less than 26 dB, 64QAM is selected.

[Effects of embodiment]
According to the present communication device, the present communication method, and the present program, in the communication device that constructs a network using an ad hoc multicast routing protocol and performs multicast communication, in the network unit 10, the IP address-MAC address table holding unit 13: The combination of IP address and MAC address is extracted and stored from the received MAC frame of the ad hoc routing message, and the quality information management unit 14 stores the communication quality at the time of reception as node communication quality in correspondence with the IP address. Then, when transmitting multicast communication, the multicast modulation method determining unit 15 outputs to the quality information management unit 14 a list of child node IP addresses that are relay nodes and receiving nodes corresponding to the combination of the source IP address and destination IP address. Then, the quality information management unit 14 outputs the lowest value of the communication quality corresponding to the input IP address list to the multicast modulation method determining unit 15, and the multicast modulation method determining unit 15 determines the lowest value of the communication quality corresponding to the lowest value of the communication quality. Since the communication device, communication method, and program select the modulation method to be used, it is possible to select an appropriate modulation method for communication stations on the actual multicast communication path, and eliminate the influence of communication stations not on the path. This has the effect of ensuring good communication quality.

The present invention provides wireless communication in which a modulation method can be selected according to the line conditions of nodes on a multicast communication route, eliminating the influence of other communication stations, preventing communication errors, and ensuring communication quality. Suitable for devices, wireless communication methods and programs. This application claims priority benefit based on Japanese Patent Application No. 2020-086729 filed on May 18, 2020, and the entire disclosure thereof is incorporated herein by reference.

10, 40... Network section, 11, 41... Ad hoc multicast routing section, 12, 42... Frame generation/analysis section, 13... IP address-MAC address table holding section, 14... Quality information management section, 15... Multicast modulation method determination 20, 50... Radio access control section, 21, 51... FCS/transmission timing setting section, 22, 52... Control frame analysis section, 23, 53... Transmission timing control section, 24, 54... FCS/transmission timing analysis section , 25, 55... Unicast modulation method determination section, 30, 60... Wireless signal processing/high frequency section, 71... Source IP address, 72... Destination IP address,
73-1 to 73-n…Child node IP address

Claims (6)

A communication device that constructs a network using an ad hoc multirouting protocol and performs multicast communication,
comprising a network unit that controls the multicast communication and a wireless access control unit that controls transmission timing,
The network unit stores communication quality of a plurality of nodes acquired from the radio access control unit at the time of reception as node quality information, and determines an optimal route corresponding to the group of multicast communication when transmitting the multicast communication. generates a list of receiving station and relay station nodes on the route, refers to the node quality information, and selects the lowest communication quality corresponding to the nodes included in the list. A communication device characterized in that the communication device calculates a value and selects a modulation method based on the lowest value. The wireless access control unit outputs the received MAC frame and its reception quality to the network unit,
The network section,
an ad-hoc multicast routing unit that determines an optimal route corresponding to a group of multicast communications when transmitting multicast communications, and generates an IP address list as a list indicating IP addresses of nodes of receiving stations and relay stations on the route; and,
The reception quality of the MAC frame input from the radio access control unit and the combination of the MAC address and IP address included in the MAC frame are stored in correspondence as node quality information, and an IP address list is input . then, a quality information management unit that refers to the node quality information and outputs the lowest value of reception quality corresponding to the IP address included in the input IP address list;
When transmitting multicast communication, an IP address list generated according to the group of multicast communication is obtained from the ad hoc multicast routing section , the obtained IP address list is output to the quality information management section, and the quality 2. The communication device according to claim 1, further comprising a multicast modulation method determining section that selects a modulation method according to the lowest value of the reception quality input from an information management section. 3. The communication device according to claim 1, wherein the reception quality is an equalization error or a signal-to-noise ratio. The network department
an IP address-MAC address table holding unit that obtains a combination of an IP address and a MAC address from a MAC frame of a received ad-hoc message and generates an IP address-MAC address table;
4. The communication device according to claim 2, wherein the quality information management unit generates node quality information by referring to the IP address-MAC address table. A communication method in a communication device that constructs a network using an ad hoc multirouting protocol and performs multicast communication,
The communication device stores the communication quality of a plurality of nodes acquired at the time of reception as node quality information, and when transmitting multicast communication, determines the optimal route corresponding to the group of multicast communication, and transmits information on the route. generate a list of nodes of receiving stations and relay stations, refer to the node quality information, find the lowest value of the lowest quality among the communication quality corresponding to the nodes included in the list , and set the lowest value to the lowest value. A communication method characterized by selecting a modulation method based on. A program that operates on a communication device that constructs a network using an ad hoc multirouting protocol and performs multicast communication,
The communication device stores the communication quality of a plurality of nodes acquired at the time of reception as node quality information, and when transmitting multicast communication, determines the optimal route corresponding to the group of multicast communication, and transmits the communication quality on the route. generate a list of nodes of receiving stations and relay stations, refer to the node quality information, find the lowest value of the lowest quality among the communication quality corresponding to the nodes included in the list , and set the lowest value to the lowest value. A program characterized in that it functions to select a modulation method based on the following.

Images