JP2022126096A - ad hoc network system - Google Patents

Abstract

To reduce the time required for switching communication speeds in a single ad hoc network in which wireless communication terminals with different communication speeds are mixed.SOLUTION: A plurality of wireless communication terminals 1-8 on an ad hoc network system 101 includes: a first wireless communication terminal compatible only with a first communication speed S1; and a second wireless communication terminal compatible with both the first communication speed S1 and a second communication speed S2. Each transmitting terminal of the plurality of wireless communication terminals 1-8 on a transmitting side transmits packets at a common communication speed, with which both of a transmitting terminal and a receiving terminal are compatible, to each receiving terminal of the plurality of wireless communication terminals 1-8 on a receiving side. A preamble of the packets includes a sequence pattern that is recognized as the same pattern at both the first and second communication speeds S1 and S2 and compatible with the packet's communication speed.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to ad-hoc network systems.

A method has been proposed for realizing random access while reducing overhead in an ad-hoc network system in which multiple wireless communication terminals with different communication speeds coexist.

For example, Patent Document 1 describes a packet containing a known fixed-rate general decryption part that all wireless communication terminals can decrypt and an arbitrary-rate advanced decryption part that only some wireless communication terminals can decrypt. stated to be sent. Further, Patent Document 2 proposes forming an individual ad-hoc network for each communication speed. Specifically, a wireless communication terminal desiring to form an ad-hoc network transmits a control message to a plurality of adjacent wireless communication terminals, and forms an ad-hoc network with the wireless communication terminals that have responded. A wireless communication terminal that wants to form an ad-hoc network sends the above control message for each communication method with a different communication speed, and forms an individual ad-hoc network for each communication method with a terminal that responds to the control message. do.

JP 2008-118692 A Japanese Patent Application Laid-Open No. 2003-324443

According to the technique of Patent Document 1, every time a wireless communication terminal transmits a packet, it is necessary to switch the communication speed between the low-speed general decryption unit and the high-speed advanced decryption unit. There is a problem of requiring

Further, the technique of Patent Document 2 forms an individual ad-hoc network for each communication speed, and does not mix different communication speeds within a single ad-hoc network.

The present disclosure has been made to solve the above problems, and aims to reduce the time required to switch communication speeds in a single ad-hoc network in which wireless communication terminals with different communication speeds coexist. do.

An ad-hoc network system of the present disclosure includes a plurality of wireless communication terminals that wirelessly communicate with each other. The plurality of wireless communication terminals includes a first wireless communication terminal that is at least one wireless communication terminal compatible only with a first communication speed, and a first communication speed and a second communication that is faster than the first communication speed. and a second wireless communication terminal that is at least one wireless communication terminal that supports both speed and speed. A transmitting terminal, which is each of a plurality of wireless communication terminals on the transmitting side, selects a transmitting terminal between the first communication speed and the second communication speed with respect to a receiving terminal, which is each of a plurality of wireless communication terminals on the receiving side. The packet is transmitted at the common communication speed, which is the communication speed supported by both the terminal and the receiving terminal. The packet preamble includes an arrangement pattern that is recognized as the same pattern at both the first communication speed and the second communication speed and that corresponds to the packet communication speed.

According to the ad-hoc network system of the present disclosure, it is possible to reduce the time required for switching communication speeds in a single ad-hoc network in which wireless communication terminals with different communication speeds coexist.

1 is a diagram showing the configuration of an ad-hoc network system according to Embodiment 1; FIG. 2 is a diagram showing the configuration of packets communicated between wireless communication terminals in the ad-hoc network system of Embodiment 1; FIG. 2 is a diagram showing the configuration of a wireless communication terminal in the ad-hoc network system of Embodiment 1; FIG. 4 is a flowchart showing transmission processing of a wireless communication terminal in the ad-hoc network system of Embodiment 1; 4 is a flowchart showing reception processing of a wireless communication terminal in the ad-hoc network system of Embodiment 1; 10 is a flow chart showing transmission processing of a wireless communication terminal in the ad-hoc network system of Embodiment 2; 2 is a diagram showing the hardware configuration of a wireless communication terminal; FIG. 2 is a diagram showing the hardware configuration of a wireless communication terminal; FIG.

<A. Embodiment 1>
<A-1. Configuration>
FIG. 1 is a configuration diagram of an ad-hoc network system 101 according to this embodiment. The ad-hoc network system 101 comprises a plurality of distributed wireless communication terminals 1-8. The ad-hoc network system 101 may have two or more wireless communication terminals, but in the following description, as shown in FIG. 1, the ad-hoc network system 101 includes eight wireless communication terminals 1-8. shall be prepared.

Each wireless communication terminal 1-8 communicates with other adjacent wireless communication terminals 1-8. All wireless communication terminals 1-8 are capable of communication at the first communication speed S1. Some of the wireless communication terminals 1-3 are capable of communication not only at the first communication speed S1 but also at a higher second communication speed S2. In other words, the wireless communication terminal 4-8 is a first wireless communication terminal that supports only the first communication speed S1, and the wireless communication terminal 1-3 supports both the first communication speed S1 and the second communication speed. This is a second wireless communication terminal compatible with both S2. In FIG. 1, the thickness of the arrows between the wireless communication terminals 1-8 indicates the difference in communication speed.

The second communication speed S2 is A times the first communication speed S1. A is an integer of 2 or more. That is, the second communication speed S2 is faster than the first communication speed S1. Although the wireless communication terminal 1-3 is capable of communicating at both the first communication speed S1 and the second communication speed S2, it is not possible to achieve both at the same time. Therefore, the wireless communication terminal 1-3 needs to switch between the first communication speed S1 and the second communication speed S2 according to the communication partner.

FIG. 2 shows a format of a packet transmitted from a wireless communication terminal 1-3 compatible with both a first communication speed S1 and a second communication speed S2 to another wireless communication terminal 1-8 in the ad-hoc network system 101. is shown. A packet includes a preamble, SFD (Start Frame Delimiter), PHR (PHY Header), and PSDU (PLCP Service Data Unit). The preamble is a pattern of 0s or 1s, and this pattern differs according to the packet communication speed. That is, the preamble pattern corresponds to the packet communication speed. Hereinafter, the preamble pattern will be referred to as a "preamble pattern". The preamble pattern is pattern 1 "0000...00" at the first communication speed S1, and pattern 2 "1111...11" at the second communication speed S2. In this way, the packets transmitted by the wireless communication terminals 1-3 have different arrangement patterns in the preamble according to the communication speed.

Also, all wireless communication terminals 1-8 can determine the preamble pattern of the packet regardless of the communication speed of the packet. In other words, the packet preamble is recognized as the same pattern at both the first communication speed S1 and the second communication speed S2. Therefore, in the above example, the preamble pattern of the packet transmitted at the second communication speed S2 is identified as "1111...11" even by the wireless communication terminal 4-8 which cannot communicate at the second communication speed S2. . The present embodiment can be applied to modulation schemes such as GFSK (Gaussian frequency-shift keying) or QPSK (quadrature phase shift keying), in which the symbol state does not change for the same data regardless of the communication speed.

FIG. 3 shows a functional configuration of a wireless communication terminal 200 that configures the ad-hoc network system 101. As shown in FIG. A radio communication terminal 200 corresponds to each of the radio communication terminals 1 to 8 in FIG. As shown in FIG. 3, the radio communication terminal 200 includes an information storage unit 201, a central control unit 202, a packet generation unit 203, a radio transmission unit 204, an antenna 205, a radio reception unit 206, and a packet analysis unit 207. be done.

Information storage unit 201 stores execution procedure instructions executed by central control unit 202, information obtained from analysis results of received packets, information on communication speeds supported by other wireless communication terminals 200 with which communication has once been performed, and the like. be. Hereinafter, the communication speed supported by the wireless communication terminal 200 will be referred to as a supported communication speed, and information on the supported communication speed will be referred to as supported communication speed information.

Central control unit 202 manages a series of processing including transmission processing and reception processing in wireless communication terminal 200 .

Packet generating section 203 generates a packet signal to be transmitted from its own wireless communication terminal 200 to another wireless communication terminal 200 . Here, the packet includes a data packet and the like. Packet generator 203 generates a packet signal in the format shown in FIG.

Radio transmission section 204 performs radio transmission processing of the packet signal generated by packet generation section 203 according to a predetermined modulation method and communication speed.

Antenna 205 wirelessly transmits a signal to another wireless communication terminal 200 on a predetermined frequency channel, and collects signals sent from other wireless communication terminal 200 .

Radio receiving section 206 performs reception processing of packet signals from other radio communication terminals 200 collected by antenna 205 .

Packet analysis section 207 analyzes packet signals received from other wireless communication terminals 200 . Received packets are analyzed and processed according to execution procedure instructions executed in the central control unit 202 .

<A-2. Sending process>
Next, the operation of wireless communication terminal 200 in ad-hoc network system 101 transmitting packets to other wireless communication terminals 200 in the same ad-hoc network system 101 will be described with reference to the flowchart of FIG. Hereinafter, the wireless communication terminal 200 that transmits packets will be referred to as a transmitting terminal, and the wireless communication terminal 200 that will receive packets will be referred to as a receiving terminal.

When the transmission terminal starts transmission control, the transmission terminal determines whether or not it supports the second communication speed S2 (step S101). When the transmitting terminal supports the second communication speed S2, that is, when the wireless communication terminal 1-3 is capable of communicating at the second communication speed S2, the transmission to the receiving terminal, which is the other party of transmission, is the first time. It is determined whether or not it is transmission (step S102).

In step S102, if the transmission to the receiving terminal is the first time, the transmitting terminal sets the preamble pattern to "0000...00", includes the data and its corresponding communication speed information in the packet, and transmits the data at the first communication speed S1. Send (step S103). At this point, since it is unknown to the transmitting terminal whether the receiving terminal supports the second communication speed S2, the transmitting terminal must select the first communication speed that both itself and the receiving terminal can surely support. Send packets at speed S1. A communication speed supported by both the transmitting terminal and the receiving terminal is also called a common communication speed.

Next, the transmitting terminal waits for an ACK response from the receiving terminal (step S104). Here, the transmitting terminal waits for an ACK packet having a preamble pattern of either "0000...00" or "1111...11" to be returned from the receiving terminal. If there is no ACK response from the receiving terminal (No in step S105), the transmitting terminal returns to the process of step S103 and retransmits the packet.

If there is an ACK response from the receiving terminal (Yes in step S105), the transmitting terminal determines whether the preamble pattern of the ACK packet is "1111...11" (step S106). If the preamble pattern of the ACK packet is "0000...00", the transmitting terminal determines that the receiving terminal does not support the second communication speed S2, and receives the ACK packet at the first communication speed S1 (step S109).

On the other hand, if the preamble pattern of the ACK packet is "1111...11", the transmitting terminal determines that the receiving terminal supports the second communication speed S2, and switches the communication speed to the second communication speed S2. An ACK packet is received (step S107).

As described above, in step S107 or step S109, the transmitting terminal stores information on the compatible communication speed of the receiving terminal in the information storage unit 201 in step S108, and completes the transmission process. .

If the communication with the receiving terminal is the second time or later in step S102, the transmitting terminal performs transmission at the communication speed supported by the receiving terminal stored in the previous step S108. Specifically, the transmitting terminal determines whether or not the receiving terminal supports the second communication speed S2 based on the compatible communication speed information of the receiving terminal stored in the information storage unit (step S110). If the receiving terminal supports the second communication speed S2 in step S110, the transmitting terminal sets the preamble pattern to "1111...11" and transmits the packet at the second communication speed S2 (step S114). Thus, the transmitting terminal transmits packets at the highest communication speed among the common communication speeds. Then, the transmitting terminal waits for an ACK response having a preamble pattern of "1111...11" at the second communication speed S2 (step S115). After that, if there is no ACK response with the preamble pattern of "1111...11" from the receiving terminal (No in step S116), the transmitting terminal returns to the process of step S114 and retransmits the packet. Also, if there is an ACK response with a preamble pattern of "1111...11" from the receiving terminal (No in step S116), the transmitting terminal completes the transmission process.

Whether the transmitting terminal does not support the second communication speed S2 (No in step S101), or whether the transmitting terminal supports the second communication speed S2 but does not support the second communication speed S2. When performing the second and subsequent transmissions to the terminal (No in step S110), the transmitting terminal sets the preamble pattern to "0000...00" and transmits the packet at the first communication speed S1, which is the common communication speed. (Step S111). Then, the transmitting terminal waits for an ACK response having a preamble pattern of "0000...00" at the first communication speed S1 (step S112). After that, if there is no ACK response with a preamble pattern of "0000...00" from the receiving terminal (No in step S113), the transmitting terminal returns to the process of step S111 and retransmits the packet. Also, if there is an ACK response with a preamble pattern of "0000...00" from the receiving terminal, the transmitting terminal completes the transmission process.

<A-3. Receiving process>
Next, the operation of the receiving terminal within the ad-hoc network system 101 receiving packets from other transmitting terminals within the same ad-hoc network system 101 will be described with reference to the flowchart of FIG.

Upon starting reception control, the receiving terminal determines whether or not it supports the second communication speed S2 (step S201).

If the receiving terminal itself is the wireless communication terminal 1-3 that supports the second communication speed S2 (Yes in step S201), the receiving terminal either "0000...00" or "1111...11". It waits for reception of a preamble pattern (step S202). After that, if the preamble pattern received by the receiving terminal is "1111...11" (No in step S203), the receiving terminal communicates with the transmitting terminal after the second time, and the transmitting terminal communicates with the second communication. It is recognized that packets are being transmitted at speed S2. Therefore, the receiving terminal switches the communication speed to the second communication speed S2 and receives the packet (step S204).

On the other hand, if the preamble pattern received after step S202 is "0000...00", the receiving terminal switches the communication speed to the first communication speed S1 and receives the packet (step S205). Thus, the receiving terminal receives packets at a communication speed corresponding to the preamble pattern. The reason why the transmitting terminal transmits the packet at the first communication speed S1 to the receiving terminal corresponding to the second communication speed S2 is that the communication is the first time, or that the transmitting terminal has changed to the first communication speed S1. There are two possible ways: Therefore, the receiving terminal determines whether or not the transmitting terminal supports the second communication speed S2 from the compatible communication speed information of the transmitting terminal included in the packet received in step S205 (step S206). Here, if the packet does not include information on the communication speed supported by the transmitting terminal, the receiving terminal may determine that the transmitting terminal does not support the second communication speed S2.

After receiving the packet from the transmitting terminal, the receiving terminal sets the preamble pattern to "1111...11" if the transmitting terminal supports the second communication speed S2 (Yes in step S204 or step S206), ACK response is performed at the communication speed S2 of 2 (step S207). The preamble pattern of the ACK packet is recognized as the same pattern at any communication speed and corresponds to the communication speed of the ACK packet, like the preamble pattern of the packet transmitted from the transmitting terminal to the receiving terminal. Thus, the reception process is completed.

After receiving the packet from the transmitting terminal, if the transmitting terminal does not support the second communication speed S2 (No in step S206), the receiving terminal sets the preamble pattern to "0000...00" and sets the preamble pattern to the first communication speed. An ACK response is made in S1 (step S210). Thus, the receiving terminal returns an ACK packet to the transmitting terminal at the common communication rate. Thus, the reception process is completed.

If the receiving terminal itself is the wireless communication terminal 4-8 that does not support the second communication speed S2 (No in step S201), it waits for reception of the preamble pattern "0000...00" at the first communication speed S1. (Step S208). After that, when the receiving terminal receives the preamble pattern of "0000...00", it receives the packet as it is at the first communication speed S1 (step S209). Then, the receiving terminal sets the preamble pattern to "0000...00" and makes an ACK response at the first communication speed (step S210). Thus, the reception process is completed.

In the above description, the ad-hoc network system 101 is assumed to consist of eight wireless communication terminals 1-8 capable of mutual communication. However, the number of wireless communication terminals constituting the ad-hoc network system 101 is not limited to eight, and any number of two or more is assumed. Further, in the above description, among the wireless communication terminals 1-8 constituting the ad-hoc network system 101, the wireless communication terminal 1-3 supports both the first communication speed and the second communication speed. However, the number of wireless communication terminals compatible with both communication speeds is not limited to three, and may be less than the number of wireless communication terminals constituting ad-hoc network system 101 . Also, in the above description, "0000...00" and "1111...11" are shown as examples of preamble patterns, but preamble patterns are not limited to these.

The ad-hoc network system 101 is applied to, for example, a sensor network system composed of sensor terminals each having a wireless communication function.

<A-4. Effect>
The plurality of wireless communication terminals 1-8 included in the ad-hoc network system 101 of Embodiment 1 include a first wireless communication terminal 4-8, which is at least one wireless communication terminal that supports only the first communication speed S1, A second wireless communication terminal 1-3, which is at least one wireless communication terminal compatible with both a first communication speed S1 and a second communication speed S2 higher than the first communication speed S1, is provided. A transmitting terminal, which is each of the plurality of wireless communication terminals 1-8 on the transmitting side, transmits a first communication speed S1 and a second communication speed S1 to a receiving terminal, which is each of the plurality of wireless communication terminals 1-8 on the receiving side. Among the communication speeds S2, packets are transmitted at a common communication speed, which is a communication speed supported by both the transmitting terminal and the receiving terminal. By performing wireless communication at the common communication speed in this manner, wireless communication is realized in the ad-hoc network system 101 in which the first wireless communication terminal and the second wireless communication terminal coexist. Also, the preamble of this packet includes an arrangement pattern that is recognized as the same pattern at both the first communication speed S1 and the second communication speed S2 and that corresponds to the packet communication speed. Therefore, the receiving terminal, which is the second wireless communication terminal, can acquire the communication speed of the packet from the preamble pattern of the packet, switch to the communication speed, and receive the packet. That is, the receiving terminal, which is the second wireless communication terminal, receives packets at a communication speed corresponding to the arrangement pattern included in the packet preamble, out of the first communication speed S1 and the second communication speed S2. As a result, since the transmitting terminal does not need to switch between the first communication speed S1 and the second communication speed S2 during transmission, it is possible to reduce the overhead caused by switching the communication speed.

In addition, in the ad-hoc network system 101 of the first embodiment, the transmitting terminal, which is the second wireless communication terminal 1-3, is the information of the communication speed that itself corresponds to the packet at the time of initial transmission to the receiving terminal. The packet may be transmitted at the first communication speed S1 including the compatible communication speed information. As a result, even if the arrangement pattern included in the preamble of the packet received from the transmitting terminal corresponds to the first communication speed S1, the receiving terminal can determine that the transmitting terminal corresponds to the second communication speed S2 based on the compatible communication speed information. you can figure out what you are doing.

Also, in the ad-hoc network system 101 of the first embodiment, the receiving terminal may send back an ACK packet to the transmitting terminal at the common communication speed in response to the packet received from the transmitting terminal. The preamble of this ACK packet is recognized as the same at both the first communication speed S1 and the second communication speed S2, and includes an arrangement pattern corresponding to the communication speed of the ACK packet. Then, when the packet received from the transmitting terminal includes compatible communication speed information, the receiving terminal, which is the second wireless communication terminal 1-3, acknowledges the faster one of the common communication speeds based on the compatible communication speed information. Determine the communication speed of packets. As a result, the receiving terminal, which is the second wireless communication terminal 1-3, informs the transmitting terminal, which is the second wireless communication terminal 1-3, that it supports the second communication speed S2. can let you know.

Further, in the ad-hoc network system 101 of Embodiment 1, the transmitting terminal may acquire and store the communication speed supported by the receiving terminal based on the sequence pattern included in the preamble of the ACK packet received from the receiving terminal. . As a result, the transmitting terminal can use the stored communication speed information to determine the common communication speed and transmit packets in the next communication with the receiving terminal.

<B. Embodiment 2>
<B-1. Configuration>
In the ad-hoc network system 101 of Embodiment 1, when the transmitting terminal performs the second and subsequent transmissions to the same receiving terminal, the preamble pattern of the packet is fixed to "0000...00" or "1111...11", Communication speed is also fixed. On the other hand, in the ad-hoc network system 102 of Embodiment 2, the transmitting terminal changes the communication speed and packet preamble pattern according to the situation even for the second and subsequent transmissions to the same receiving terminal.

The configurations of ad-hoc network system 102 and wireless communication terminal 200 in ad-hoc network system 102 are as shown in FIGS.

<B-2. Operation>
The operation of the transmitting terminal transmitting a packet to the receiving terminal in the ad-hoc network system 102 will be described below with reference to the flowchart of FIG. The flowchart of FIG. 6 is obtained by inserting step S110A between steps S110 and S114 of the flowchart of FIG. Since the processing other than step S110A is the same as that of the first embodiment, the description is omitted here.

If it is the second or later transmission from the transmitting terminal to the receiving terminal and both the transmitting terminal and the receiving terminal support the second communication speed S2 (Yes in step S110), the transmitting terminal communicates with the receiving terminal. is equal to or less than a predetermined threshold (step S110A). The PER is calculated by (the number of times ACK packets are received/the number of times packets are transmitted). If the process of step S110A is the first time, the PER of the communication with the receiving terminal has not yet been calculated, so the transmitting terminal always determines Yes in step S110A and proceeds to the next process of step S114.

In Embodiment 1, after transmitting a packet at the second communication speed S2, the transmitting terminal repeatedly retransmits the packet at the same second communication speed S2 if there is no ACK response from the receiving terminal within a certain period of time. (Step S114). On the other hand, in the second embodiment, if the transmitting terminal does not receive an ACK response from the receiving terminal within a certain period of time after transmitting the packet at the second communication speed S2, the PER of the communication with the receiving terminal is reduced in step S110A. is less than or equal to a predetermined threshold. If the PER is equal to or less than the threshold, the transmitting terminal determines that the communication quality with the receiving terminal is good, and retransmits the packet at the second communication speed S2 (step S114). On the other hand, if the PER exceeds the threshold, the transmitting terminal determines that the communication quality with the receiving terminal is poor, reduces the communication speed to the first communication speed S1, and retransmits the packet (step S111).

In the above description, the transmitting terminal judges the communication quality with the receiving terminal based on the PER, and switches the communication speed in retransmission control. However, the criterion for switching the communication speed is not limited to PER, and may be based on another index representing communication quality. Also, at least one of the transmitting terminal and the receiving terminal may determine the communication quality. For example, when the RSSI (Received Signal Strength Indicator) of the signal received from the transmitting terminal is equal to or less than a predetermined threshold, the receiving terminal determines that the communication quality is poor and requests the transmitting terminal to switch the communication speed. Then, in response to this switching request, the transmitting terminal reduces the communication speed from the second communication speed S2 to the first communication speed S1.

<B-3. Effect>
In the ad-hoc network system 102 of Embodiment 2, at least one of the transmitting terminal and the receiving terminal, both of which are the second wireless communication terminals 1-3, sets an index representing the communication quality between the transmitting terminal and the receiving terminal. The transmission terminal reduces the packet communication speed based on the index. Therefore, according to the ad-hoc network system 102, when the communication quality deteriorates between the wireless communication terminals 200 communicating at the second communication speed S2, the communication speed is efficiently lowered to the first communication speed S1, It is possible to perform stable communication.

<C. Hardware configuration>
Information storage unit 201, central control unit 202, packet generation unit 203, radio transmission unit 204, radio reception unit 206, and packet analysis unit 207 of radio communication terminal 200 shown in FIG. ) is implemented by a processing circuit 81 shown in FIG. Dedicated hardware may be applied to the processing circuit 81, or a processor that executes a program stored in a memory may be applied. The processor is, for example, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.

When the processing circuit 81 is dedicated hardware, the processing circuit 81 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these. Each function of each unit such as the packet generation unit 203 may be realized by a plurality of processing circuits 81, or the functions of each unit may be collectively realized by one processing circuit.

When the processing circuit 81 is a processor, the functions of the packet generator 203 and the like are realized by a combination of software and the like (software, firmware, or software and firmware). Software or the like is written as a program and stored in memory. As shown in FIG. 8, a processor 82 applied to a processing circuit 81 reads out and executes a program stored in a memory 83 to implement the functions of each section. That is, the wireless communication terminal 200 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the processing of the packet generator 203 and the like. In other words, this program can be said to cause the computer to execute the procedure or method of the packet generator 203 and the like. Here, the memory 83 includes non-volatile memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Or volatile semiconductor memory, HDD (Hard Disk Drive), magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disk) and its drive device, etc., or any storage medium that will be used in the future There may be.

The configuration in which each function such as the packet generation unit 203 is realized by either hardware or software has been described above. However, the configuration is not limited to this, and a configuration in which part of the packet generation unit 203 and the like is realized by dedicated hardware and another part is realized by software or the like may be employed.

In addition, it is possible to combine each embodiment freely, and to modify|transform and abbreviate|omit each embodiment suitably.

1-8, 200 wireless communication terminal, 101, 102 ad-hoc network system, 201 information storage unit, 202 central control unit, 203 packet generation unit, 204 wireless transmission unit, 205 antenna, 206 wireless reception unit, 207 packet analysis unit, S1 first communication speed, S2 second communication speed;

Claims (6)

An ad-hoc network system comprising a plurality of wireless communication terminals that wirelessly communicate with each other,
The plurality of wireless communication terminals are
a first wireless communication terminal that is at least one wireless communication terminal that supports only the first communication speed;
a second wireless communication terminal that is at least one wireless communication terminal compatible with both the first communication speed and a second communication speed higher than the first communication speed;
A transmitting terminal, which is each of the plurality of wireless communication terminals on the transmitting side, transmits the first communication rate and the second communication rate to a receiving terminal, which is each of the plurality of wireless communication terminals on the receiving side. transmitting packets at a common communication speed, which is a communication speed supported by both the transmitting terminal and the receiving terminal,
The preamble of the packet is recognized as the same pattern at both the first communication speed and the second communication speed, and includes an arrangement pattern corresponding to the communication speed of the packet,
ad-hoc network system. The receiving terminal, which is the second wireless communication terminal, receives the packet at a communication speed corresponding to an arrangement pattern included in the preamble of the packet, out of the first communication speed and the second communication speed.
The ad-hoc network system according to claim 1. When the transmitting terminal, which is the second wireless communication terminal, transmits the packet for the first time to the receiving terminal, the transmitting terminal includes compatible communication speed information, which is information on a communication speed that the transmitting terminal supports, in the first communication. transmitting said packets at a rate;
3. The ad-hoc network system according to claim 1 or 2. The receiving terminal returns an ACK packet to the transmitting terminal at the common communication speed in response to the packet received from the transmitting terminal;
The preamble of the ACK packet is recognized as the same at both the first communication speed and the second communication speed, and includes an arrangement pattern corresponding to the communication speed of the ACK packet,
When the packet received from the transmitting terminal includes the compatible communication speed information, the receiving terminal, which is the second wireless communication terminal, performs communication at the highest communication speed among the common communication speeds based on the compatible communication speed information. determining the speed as the communication speed of the ACK packet;
The ad-hoc network system according to claim 3. The transmitting terminal acquires and stores information on the communication speed supported by the receiving terminal based on the arrangement pattern included in the preamble of the ACK packet received from the receiving terminal.
The ad-hoc network system according to claim 4. At least one of the transmitting terminal and the receiving terminal calculates an index representing communication quality between the transmitting terminal and the receiving terminal,
the transmitting terminal reduces the communication speed of the packet based on the indicator;
The ad-hoc network system according to any one of claims 1 to 5.

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