JP4617478B2 - Wireless communication terminal, wireless communication method, and program - Google Patents

Description

  The present invention relates to a wireless communication terminal, a wireless communication method, and a program.

  Mobile wireless communication systems, such as analog mobile phones, PDCs (Personal Digital Cellular), and PHSs (Personal Handyphone Systems), which perform mobile communications in an outdoor environment using a microwave frequency band or quasi-microwave frequency band are becoming widespread. Wireless communication systems such as cordless telephones using the millimeter wave frequency band have also been proposed and are being researched and developed.

  In particular, in wireless communication between a moving body and between a stationary body and a moving body using a millimeter wave frequency band, a microwave frequency band, or a quasi-microwave frequency band, for example, a 2 GHz band, the position of the moving body changes dynamically. By doing so, the situation of the propagation path between the two often changes greatly.

  However, in communication in such a frequency band, when a communication partner is hidden by a shield, it is attenuated by the shield. In addition, even when the distance between the two is increased, attenuation due to the distance tends to occur. Such attenuation is particularly noticeable in a frequency band suitable for Line of Sight (LoS) communication.

  Therefore, such attenuation has caused problems that the transmission quality deteriorates or communication itself becomes impossible.

As a technique for solving such a problem, a technique for adaptively and autonomously forming a group in wireless communication terminals and performing communication using this group has been proposed. Such a technique is disclosed in the following documents, for example.
JP 2003-134032 A

  In this way, when wireless communication terminals belonging to different groups communicate with each other using a group formed autonomously, from which wireless communication terminal of the group to which the source wireless communication terminal belongs, the destination wireless communication There is a great demand for efficient communication by appropriately determining which wireless communication terminal in a group to which a terminal belongs to which communication relay is to be performed.

  The present invention has been made to solve the above-described problems, and is suitable for efficiently performing communication with wireless communication terminals belonging to different groups in wireless communication for autonomously forming groups. It is an object of the present invention to provide a terminal, a wireless communication method, and a program for realizing these on a software radio.

  In order to achieve the above object, the following invention is disclosed in accordance with the principle of the present invention.

  A wireless communication terminal according to a first aspect of the present invention is a wireless communication terminal that forms a group by becoming an upper station or a lower station, and each group includes one upper station and zero or more lower stations. The wireless communication terminal communicates a packet with another wireless communication terminal belonging to the same group or a different group, and accepts a reception unit, a transmission unit within the group, a transmission unit outside the group, a storage unit, a reception unit, reception power A processing unit, a packet reception processing unit, and an out-of-group relay unit are configured as follows.

  First, the reception unit receives an input of a packet in which a destination, a transmission source, and transmission information are specified.

  On the other hand, the intra-group transmission unit transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal that belongs to the same group as the wireless communication terminal.

  Further, the out-of-group transmission unit transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal that belongs to a different group from the wireless communication terminal.

The intra-group relay unit, when the destination of the accepted packet is another wireless communication terminal belonging to the same group as the wireless communication terminal,
(A) If the wireless communication terminal is an upper station, the intra-group transmission unit transmits the packet to the other wireless communication terminal,
(B) If the wireless communication terminal is a lower station, the intra-group transmission unit transmits the packet to the upper station of the group.

  On the other hand, the storage unit stores transmission parameters in association with candidate sets of external relay terminals and external destination terminals.

  Further, the receiving unit receives a packet transmitted from another wireless communication terminal.

  Then, when the source of the received packet is another wireless communication terminal belonging to a different group from the wireless communication terminal, the received power processing unit sets the wireless communication terminal as an external relay terminal and the other wireless communication terminal Is associated with the received power of the packet as a transmission parameter and stored in the storage unit, the wireless communication terminal as a transmission source, and the upper station of the group to which the wireless communication terminal belongs as a destination A new packet that designates transmission information that designates transmission information that designates each of the wireless communication terminals as external relay terminals, other wireless communication terminals as external destination terminals, and reception power of the packets as transmission parameters, respectively. To accept as input.

On the other hand, the packet reception processing unit, when the received packet or the destination of the received packet is the wireless communication terminal,
(C) If the transmission information specified in the packet is another packet, the receiving unit accepts the other packet as input,
(D) When an external relay terminal, an external destination terminal, and a transmission parameter are specified in the transmission information specified in the packet, a candidate set of the specified external relay terminal and the specified external destination terminal The transmission parameters are associated with each other and stored in the storage unit, and if the wireless communication terminal is an upper station, each of the lower stations belonging to the same group as the wireless communication terminal that is not the source of the packet is set as the destination, The reception unit accepts a new packet that designates the transmission information of the packet as transmission information, with the wireless communication terminal as the source,
(E) In cases other than (c) and (d) above, the transmission information is output.

Furthermore, when the destination of the received packet is another wireless communication terminal belonging to a different group from the wireless communication terminal,
(F) If the wireless communication terminal is stored in the storage unit as the external relay terminal of the candidate set having the maximum transmission parameter among the candidate sets having the other wireless communication terminal as the external destination terminal, the packet is stored. , Let the outside-group transmission unit transmit to the other wireless communication terminal,
(G) If other than the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, the transmission The receiving unit accepts a new packet that designates the candidate group of external relay terminals with the maximum parameter as the destination, the wireless communication terminal as the source, and designates the packet as transmission information.

  In addition, the wireless communication terminal of the present invention further includes an attenuation unit, and the attenuation unit can be configured to attenuate each of the transmission parameters stored in the storage unit over time.

  In the wireless communication terminal according to the present invention, the attenuation unit multiplies each transmission parameter stored in the storage unit by a predetermined constant larger than 0 and smaller than 1 every time a predetermined unit time elapses. It can be constituted as follows.

  A wireless communication method according to another aspect of the present invention is executed by a wireless communication apparatus that forms a group by becoming an upper station or a lower station, and each group includes one upper station and zero or more lower stations. The wireless communication terminal communicates a packet with another wireless communication terminal belonging to the same group or a different group, and the wireless communication apparatus transmits a transmission parameter to a candidate set of the external relay terminal and the external destination terminal. The storage unit stores the data in association with each other, and includes a reception process, an intra-group transmission process, an out-group transmission process, a reception process, a received power processing process, a packet reception processing process, and an out-group relay process, and is configured as follows.

  First, in the receiving step, an input of a packet in which a destination, a transmission source, and transmission information are specified is received.

  On the other hand, in the intra-group transmission step, a packet in which a destination, a transmission source, and transmission information are specified is transmitted to another wireless communication terminal that belongs to the same group as the wireless communication terminal.

  Further, in the out-of-group transmission step, a packet in which a destination, a transmission source, and transmission information are specified is transmitted to another wireless communication terminal that belongs to a group different from the wireless communication terminal.

In the intra-group relay process, when the destination of the accepted packet is another wireless communication terminal belonging to the same group as the wireless communication terminal,
(A) If the wireless communication terminal is an upper station, the packet is transmitted to the other wireless communication terminal in the intra-group transmission step,
(B) If the wireless communication terminal is a lower station, the packet is transmitted to an upper station of the group in an intra-group transmission step.

  On the other hand, in the receiving step, a packet transmitted from another wireless communication terminal is received.

  Further, in the received power processing step, when the source of the received packet is another wireless communication terminal belonging to a group different from the wireless communication terminal, the other wireless communication terminal is set as the external relay terminal. Is associated with the received power of the packet as a transmission parameter and stored in the storage unit, the wireless communication terminal as a transmission source, and the upper station of the group to which the wireless communication terminal belongs as a destination Accepting a new packet that designates transmission information that designates each of the wireless communication terminals as external relay terminals, the other wireless communication terminals as external destination terminals, and the reception power of the packets as transmission parameters. To accept as input.

In the packet acceptance processing step, when the received packet or the destination of the accepted packet is the wireless communication terminal,
(C) When the transmission information specified in the packet is another packet, the other packet is accepted as an input in the accepting process,
(D) When an external relay terminal, an external destination terminal, and a transmission parameter are specified in the transmission information specified in the packet, a candidate set of the specified external relay terminal and the specified external destination terminal The transmission parameters are associated with each other and stored in the storage unit, and if the wireless communication terminal is an upper station, each of the lower stations belonging to the same group as the wireless communication terminal that is not the source of the packet is set as the destination, The reception process accepts a new packet that designates the transmission information of the packet as transmission information, with the wireless communication terminal as the source,
(E) In cases other than (c) and (d) above, the transmission information is output.

On the other hand, in the out-of-group relay process, when the destination of the received packet is another wireless communication terminal belonging to a group different from the wireless communication terminal,
(F) If the wireless communication terminal is stored in the storage unit as the external relay terminal of the candidate set having the maximum transmission parameter among the candidate sets having the other wireless communication terminal as the external destination terminal, the packet is stored. , Let it transmit to the other wireless communication terminal in the outside group transmission step,
(G) If other than the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, the transmission A new packet specifying the candidate group of external relay terminals having the maximum parameter as the destination, the wireless communication terminal as the source, and designating the packet as transmission information is received in the receiving step.

  In addition, the wireless communication method of the present invention further includes an attenuation step, and in the attenuation step, each of the transmission parameters stored in the storage unit can be attenuated over time.

  In the wireless communication method of the present invention, in the attenuation step, each time a predetermined unit time elapses, each transmission parameter stored in the storage unit is attenuated by multiplying by a predetermined constant larger than 0 and smaller than 1. It can be constituted as follows.

  A program according to another aspect of the present invention is configured to cause a computer such as software radio to function as the above-described wireless communication terminal.

  By causing a computer such as software radio capable of communicating with other wireless communication terminals to execute the program of the present invention, the wireless communication terminal and the wireless communication method of the present invention can be realized.

  In addition, an information recording medium in which the program of the present invention is recorded can be distributed and sold independently from the computer such as the software radio. In addition, the program of the present invention can be transmitted, distributed, and sold via a computer communication network such as the Internet.

  In particular, when a computer such as the software radio has a programmable electronic circuit such as a DSP (Digital Signal Processor) or FPGA (Field Programmable Gate Array), the program recorded on the information recording medium of the present invention is wirelessly provided. The wireless communication terminal of the present invention can be obtained by transmitting to the computer and causing the DSP or FPGA in the computer such as the software radio to execute it.

  According to the present invention, in wireless communication for autonomously forming a group, a wireless communication terminal suitable for efficiently communicating with wireless communication terminals belonging to different groups, a wireless communication method, and software radio A program for realizing this can be provided.

  An embodiment of the present invention will be described below. In addition, embodiment described below is for description and does not limit the scope of the present invention. Therefore, those skilled in the art can employ embodiments in which each or all of these elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.

  The embodiment of the wireless communication terminal according to the present invention will be described first with reference to processing until a group is formed, then basic communication technology, and finally, a technology that is a feature of the present invention. To do. In addition, about the technique which forms a group, it is good also as employ | adopting techniques other than the technique described below, and even that case is included in the scope of the present invention.

(Group forming technology)
In the following, a technique for forming a group will be described. FIG. 1 is a schematic diagram illustrating a schematic configuration of a wireless communication terminal according to a technique up to formation of a group. Hereinafter, a description will be given with reference to FIG.

  The wireless communication terminal 101 according to the present embodiment operates in one of the operation modes of the undetermined mode, the upper station mode, and the lower station mode.

  Whether the initial detection unit 102 of the wireless communication terminal 101 can communicate with another wireless communication terminal operating in the higher station mode via the antenna 103 when the wireless communication terminal 101 is operating in the undetermined mode. Detect whether or not.

  Furthermore, when there are a plurality of communicable wireless communication terminals that operate as upper stations, the initial detection unit 102 sets the wireless communication terminal with the best propagation path condition as the upper station.

  When the initial detection unit 102 detects that communication with another wireless communication terminal operating in the higher station mode is possible, the lower station mode setting unit 104 sets the operation mode to the lower station mode, The wireless communication terminal is registered as a higher-level terminal, and dependency information indicating that it is dependent on the higher-level terminal is transmitted.

  The setting of the operation mode is stored in the operation mode storage unit 105, and the information of the upper terminal is stored in the upper terminal storage unit 106.

  On the other hand, when the initial detection unit 102 detects that communication with another wireless communication terminal operating in the higher station mode is not possible, the higher station mode setting unit 107 sets the operation mode to the higher station mode.

  Then, the lower terminal registration unit 108 sets the operation mode to the upper station mode, and sends the subordinate information indicating that the other radio communication terminal is subordinate to the antenna 103 from another radio communication terminal operating in the lower station mode. The other wireless communication terminal is registered as a lower terminal.

  The lower terminal information is stored in the lower terminal storage unit 109.

  On the other hand, when the operation mode is set to the upper station mode, the upper station maintenance detection unit 110 determines whether or not communication with the lower terminal stored in the lower terminal storage unit 109 is possible. While it is a station, it periodically detects at predetermined time intervals.

  Further, when the operation mode is set to the lower station mode, the lower station maintenance detection unit 111 determines whether or not communication with the upper terminal stored in the upper terminal storage unit 106 is possible. While it is a station, it periodically detects at predetermined time intervals.

  The undetermined mode setting unit 112 sets the operation mode to the undetermined mode in any of the following cases.

  (A) When the upper station maintenance detection unit 110 detects that communication with a lower terminal is not possible.

  (B) When the lower station maintenance detection unit 111 detects that communication with the upper terminal is not possible.

  (C) When the operation mode is set to the upper station mode and a predetermined time has passed without any wireless communication terminal being registered as a lower terminal.

  On the other hand, the transmission unit 113 transmits a message to another wireless communication terminal.

  Furthermore, the receiving unit 114 receives a message from another wireless communication terminal.

  In this figure, illustration of a band pass filter, a modem, and the like used in a normal wireless communication terminal is omitted, but the present wireless communication terminal 101 can be realized by using a normal known technique. .

  In addition, the operation mode storage unit 105, the upper terminal storage unit 106, and the lower terminal storage unit 109 can be realized by a RAM (Random Access Memory) or the like.

  The lower station mode setting unit 104, the upper station mode setting unit 107, and the undetermined mode setting unit 112 can be realized by a CPU (Central Processing Unit) that controls the wireless communication terminal 101.

  Further, the initial detection unit 102, the lower-level terminal registration unit 108, the higher-level station maintenance detection unit 110, the lower-level station maintenance detection unit 111, the transmission unit 113, and the reception unit 114 are shared by the CPU and a normal mobile communication unit. It can be realized by working.

  In the present embodiment, as a condition for “communication is possible” with another terminal, not only communication is possible but also a carrier power-to-noise power ratio (also referred to as “CN ratio”), or the like. You may employ | adopt as requirements that the reception power of the packet transmitted from another terminal exceeds a predetermined threshold value. Enable stable communication. Hereinafter, the case where these requirements are adopted is simply referred to as “communication is possible” in order to facilitate understanding.

(Operation mode transition process)
FIG. 2 is a flowchart showing a control flow of an operation mode transition process for transitioning the operation mode of the wireless communication terminal 101 in the present embodiment. Hereinafter, a description will be given with reference to FIG.

  The wireless communication terminal 101 is set to the undetermined mode immediately after the power is turned on. First, it is checked whether or not communication with another terminal operating in the higher station mode is possible (step S201).

  If communication with another terminal operating in the upper station mode is possible (step S201; Yes), the operation mode is set to the lower station mode (step S202). At this time, the upper terminal is registered and dependent information is transmitted to the upper terminal. Then, after waiting for a predetermined time (step S203), it is checked whether or not communication with the host terminal is possible (step S204). If it is possible (step S204; Yes), the process returns to step S203. If not possible (step S204; No), the operation mode is set to the undetermined mode (step S205). As a result, the process returns to step S201.

  On the other hand, when communication with another terminal operating in the higher station mode is not possible (step S201; No), the operation mode is set to the higher station mode (step S206). While the operation mode is the upper station mode, when the dependent information is received from another terminal, the terminal is registered as a lower terminal.

  Then, after waiting for a predetermined time (step S207), it is checked whether there is any device registered as a lower terminal (step S208). If not (step S208; No), the operation mode is set to the undetermined mode. (Step S210), the process returns to Step S201.

  If there is one registered as a lower terminal (step S208; Yes), it is checked whether or not communication is possible (step S209). If communication is possible (step S209; Yes), step S207 is performed. If not (step S209; No), the operation mode is set to the undetermined mode (step S210), and the process returns to step S201.

  Note that the waiting time in step S203 and step S207 may be zero. Further, the detection of the communicable / impossible state detection and the trigger of the state transition may be processed by interruption.

(Operation mode decision)
FIG. 3 is an explanatory diagram illustrating a state in which the wireless communication terminals of the present embodiment are mounted on a vehicle, detect each other, and determine an operation mode. Hereinafter, a description will be given with reference to FIG.

  FIG. 3A shows five wireless communication terminals A, B, C, D, and E in the order of detection. Assume that all of A, B, C, D, and E are in the initial state and the operation mode is not set (or is set to the lower mode). A and B can communicate with each other, and C, D, and E can communicate with each other.

  Here, when A detects, it can be understood that B can communicate with B, but B is not an upper station. Therefore, the operation mode A is set to the upper station. FIG. 3B shows the state.

  Next, when B detects, it can be seen that communication with A of the upper station is possible. Therefore, the operation mode of B is a subordinate station, and B is informed of that fact. A registers B as a lower station, and B registers A as an upper station. FIG. 3C shows the state.

  Further, when C detects, it can be understood that both D and E are communicable, but neither is an upper station. Therefore, the operation mode of C is set to the upper station. FIG. 3D shows the state.

  Then, when D detects, it can be understood that communication with C of the upper station is possible. Therefore, the operation mode of D is a lower station, and D is notified to C of that fact. C registers D as a lower station, and D registers C as an upper station. Note that D can communicate with E, but E is not an upper station, so it is not selected.

  Further, when E detects, it can be seen that communication with C of the upper station is possible. Therefore, the operation mode of E is a lower station, and E is notified to C of that. C registers E as a lower station, and E registers C as an upper station. Note that E can communicate with D, but D is not an upper station, so it is not selected. FIG. 3 (e) shows the situation.

  As a result, A registers B as a subordinate station, and C registers D and E as subordinate stations.

  In this way, one or more lower stations are subordinate to one upper station. Therefore, grouping is performed for each upper station.

  In this way, the relationship between the upper station and the lower station is set autonomously. These updates can be executed by each wireless communication terminal 101 at an independent timing.

  In the autonomous grouping according to the present embodiment, it is ensured that the communication between the upper station and the lower stations subordinate thereto is good.

  Although communication between lower stations in the same group is expected to be good in many cases, if it is not good, communication is always possible by relaying the higher stations.

  Also, communication between the upper station and other upper stations is not good in most cases. If it is good, one should be the other subordinate station.

  Further, communication between lower stations belonging to different groups may be good or bad. This depends on the situation.

  FIG. 4 shows the relationship between the upper terminal (Master Terminal) when there are 20 wireless communication terminals 101, the subordinate terminal (Slave Terminal) subordinate thereto, and the terminal group (Terminal Group) composed of these terminals. It is explanatory drawing which shows the result of having carried out the simulation experiment about how it changes.

  FIG. 4 shows a state in which the time has elapsed in the order of (a), (b), and (c) and the wireless communication terminal 101 has moved accordingly. From this figure, it can be seen that the terminal group is configured autonomously and that the terminal group is maintained for a considerable time. Therefore, by adopting a message relay method as described later, efficient message transmission becomes possible.

(Slot structure)
In the present embodiment, messages exchanged between the transmission unit 113 and the reception unit 114 are time-divided and transmitted in slot units. FIG. 5 is a schematic diagram showing the structure of the slot employed in the present embodiment.

  One slot 501 can be divided into two times, a control signal period 502 and a data transfer period 503.

  In the control signal period 502, the following control signals are transmitted.

-Destination message (Call Notification). Information on the designated destination and notification that data information is to be transmitted to the destination are notified.

-Confirmation message (ACK). Notify that the data information has been transmitted to the specified destination or the relay destination.

-Unconfirmed message (NACK). Notifies that the destination message has arrived but no data information has been transmitted.

-Relay Offer message. Notify the destination that data information transmission may be relayed.

・ Inquiry message (Authentication Confirm). The lower station asks if the destination is subordinate to the upper station to which it belongs.

-Relay Reply Message (Authentication Reply). The lower station is notified that the destination is also subordinate from the upper station to which it is subordinate.

  On the other hand, in the data transfer period 503, a data information signal is transmitted. Data information to be transmitted is transmitted by the data information signal, but information such as destination information and relay information may be added and transmitted.

  Since the amount of information transmitted in the control signal period 502 is small and the time is short, the instantaneous transmission power in the control signal period 502 may be increased. Thereby, the transmission distance of Call Notification etc. can be lengthened.

  On the other hand, since a relatively large amount of information is transmitted in the data transfer period 503, the maximum value of the instantaneous transmission power is limited, and the reach distance is shorter than the signal transmitted in the control signal period 502.

  In the following, from the wireless communication terminal P (source terminal) subordinate to another wireless communication terminal in the terminal group 1 to the wireless communication terminal R together with the wireless communication terminal S in the terminal group 2. A situation where data information is transmitted to the subordinate radio communication terminal Q (destination terminal) will be described as an example. Note that the following description can also be applied to the case where the wireless communication terminal P is a higher-level terminal.

(Basic communication technology)
FIG. 6 is a schematic diagram showing exchange of messages when data can be directly transmitted from the wireless communication terminal P (source terminal) to the wireless communication terminal Q (destination terminal).

  In this figure, in the terminal group 2, the radio communication terminal R is the upper station (master), and the radio communication terminals S and Q are the lower stations (slave).

  First, the wireless communication terminal P broadcasts a Call Notification and then directly transmits data information (Direct Transmission).

  In this situation, since the wireless communication terminal Q was able to receive the directly transmitted data information, it returns an ACK to the wireless communication terminal P.

  By receiving this, the transmission of the data information in the wireless communication terminal P is completed successfully.

  FIG. 7 is a schematic diagram illustrating message exchange when data transmission is possible from the wireless communication terminal P (source terminal) to the wireless communication terminal Q (destination terminal) via the wireless communication terminal R (relay terminal). .

  First, the wireless communication terminal P broadcasts a Call Notification and then directly transmits data information (Direct Transmission). This is the same as the example shown in FIG.

  When the wireless communication terminal Q can receive the call notification but fails to receive the data information, a NACK is transmitted from the wireless communication terminal Q to the wireless communication terminal P. If the wireless communication terminal Q has not received Call Notification or data information, nothing is transmitted.

  In such a case, that is, when the wireless communication terminal P cannot receive ACK from the wireless communication terminal Q, it is checked whether there is a Relay Offer from another wireless communication terminal.

  In this example, a relay offer indicating that “the transmission to the wireless communication terminal Q may be relayed” is transmitted from the wireless communication terminal R to the wireless communication terminal P.

  As a result of viewing the information on the destination (wireless communication terminal Q) included in the call notification sent by broadcasting, the wireless communication terminal R can relay to the wireless communication terminal R because it is its own lower terminal. I decided that there was, and returned Relay Offer.

  Therefore, the wireless communication terminal P transmits data information addressed to the wireless communication terminal Q to the wireless communication terminal R. In the present embodiment, the data information is transmitted using a direct transmission format instead of a broadcast format.

  The wireless communication terminal R returns an ACK to the wireless communication terminal P and notifies that the data information has been received. Thereby, transmission in the wireless communication terminal P is completed successfully.

  Further, the wireless communication terminal R directly transmits the call notification and data information to the wireless communication terminal Q, and the relay is successfully completed when an ACK is returned from the wireless communication terminal Q to the wireless communication terminal R. To do.

  At the same time, the ACK (Finish) is returned from the wireless communication terminal Q to the wireless communication terminal P, so that the entire transmission is successfully completed.

  In this way, ACK is also returned from the wireless communication terminal Q to the wireless communication terminal P. As described above, the signal transmitted by the control signal period 502 has a long reach distance, so that ACK can be returned even if data information cannot be transmitted. In this way, the source can confirm that the data information has been transmitted to the destination as in TCP (Transfer Control Protocol).

  In this figure, the Relay Offer is returned only from the wireless communication terminal R, but the wireless communication terminal P may receive a plurality of Realy Offers. Among them, the one having the largest transmission power is selected, the data information is directly transmitted only to the other party, and the other party is relayed.

  FIG. 8 shows a case where data transmission from the wireless communication terminal P (source terminal) to the wireless communication terminal Q (destination terminal) can be performed via the wireless communication terminal S (secondary relay terminal) and the wireless communication terminal R (relay terminal). It is a schematic diagram which shows exchange of the message.

  First, the wireless communication terminal P broadcasts a Call Notification and then directly transmits data information (Direct Transmission). This is the same as the example shown in FIGS.

  When the wireless communication terminal Q can receive the call notification but fails to receive the data information, a NACK is transmitted from the wireless communication terminal Q to the wireless communication terminal P. If the wireless communication terminal Q has not received Call Notification or data information, nothing is transmitted.

  In such a case, that is, when the wireless communication terminal P cannot receive the ACK from the wireless communication terminal Q, it waits for Relay Offer from another wireless communication terminal.

  On the other hand, the wireless communication terminal S that has received the Call Notification makes an inquiry to the wireless communication terminal R, which is the higher-order terminal, whether “the wireless communication terminal Q is a lower terminal of the wireless communication terminal R” (Authentication Confirm).

  On the other hand, the radio communication terminal R sends to the radio communication terminal S, “Since the radio communication terminal Q is a lower terminal of the radio communication terminal R, the transmission to the radio communication terminal Q may be relayed” (Authentication Reply) Will be returned.

  Accordingly, the wireless communication terminal S transmits a Relay Offer to the wireless communication terminal P to the effect that “the transmission to the wireless communication terminal Q may be relayed”.

  Then, the wireless communication terminal P transmits data information addressed to the wireless communication terminal Q to the wireless communication terminal S.

  The wireless communication terminal S returns an ACK to the wireless communication terminal P and notifies that the data information has been received. Thereby, transmission in the wireless communication terminal P is completed successfully.

  Further, the wireless communication terminal S directly transmits data information to the wireless communication terminal R, and an ACK is returned from the wireless communication terminal R to the wireless communication terminal S, so that the relay between the wireless communication terminals S is completed successfully. .

  Further, the wireless communication terminal R performs direct transmission of data information to the wireless communication terminal Q, and the relay is successfully completed when an ACK is returned from the wireless communication terminal Q to the wireless communication terminal R.

  At the same time, the ACK (Finish) is returned from the wireless communication terminal Q to the wireless communication terminal P, so that the entire transmission is successfully completed.

  Communication within the same terminal group can also be realized by applying the above transmission method in the same manner.

  In addition, when relaying is performed, an embodiment in which the transmission source does not wait for the return of the ACK from the destination existing in the relay destination can also be adopted. For example, in the modes shown in FIG. 7 and FIG. 8, it is assumed that the data transmission to the wireless communication terminal Q is completed successfully when the wireless communication terminal P finally receives ACK (Finish). In this embodiment, data transmission is performed from the wireless communication terminal P to any one of the wireless communication terminals, and the data transmission is successfully completed when an ACK is received from the wireless communication terminal.

  Such data transmission, like UDP (User Datagram Protocol), is characterized in that high-speed transmission is possible although there is no guarantee that the packet will surely reach the other party.

  In the present embodiment, the data information message and other messages are transmitted in a time division manner. However, the above method can be similarly applied to frequency division, code division, and the like. Are also included within the scope of the present invention.

  FIG. 9 and FIG. 10 respectively show the input traffic (Input Traffic) when using the method of the embodiment according to the basic technology (Proposed) and the conventional method (Conventional), and the communication throughput. It is a graph which shows the result of having obtained the relationship between (Normalized Throughput) and communication delay (Normalized Delay) by experiment. The characteristics of the basic technology shown in these figures are that the communication throughput is improved and the communication delay is shortened as compared with the conventional technology.

(Technology that characterizes the present invention)
Now, this embodiment appropriately configures the structure of the packet specified in the data information signal transmitted in the data transfer period 503 for data transfer in the slot 501 in the basic technology described so far. The packet transmission / reception routing is performed in consideration of the reception power from the group.

  Note that the communication technology in the present embodiment may be configured in a layer above the basic technology layer in the communication model. In other words, a certain packet does not necessarily fit in one slot, but may be divided into a plurality of slots and transmitted with a serial number.

  In the packet, identification information of the wireless communication terminal that is the transmission source of the packet, identification information of the wireless communication terminal that is the destination of the packet, and transmission information including data such as a byte string are specified. Hereinafter, this is expressed as (source / destination / transmission information).

  Packets can be thought of as mere data and can be nested. For example, (A / B / (A / C / X)) is a packet which means that transmission information X from A to C is transmitted from A to B for the time being.

  Now, as described above, in the situation shown in FIG. 6, direct transmission from the wireless communication terminal P belonging to a different group to the wireless communication terminal Q is performed. The latest reception time of such direct transmission is F, and the reception power at the wireless communication terminal Q is L.

  In the situation illustrated in FIG. 7, direct transmission from the wireless communication terminal P belonging to a different group to the wireless communication terminal R is performed. The latest reception time of such direct transmission is G, and the reception power at the wireless communication terminal Q is M.

  In the situation shown in FIG. 8, direct transmission from the wireless communication terminal P belonging to a different group to the wireless communication terminal S is performed. The latest reception time of such direct transmission is H, and the reception power at the wireless communication terminal Q is N.

In this embodiment, when receiving a packet by direct transmission from outside the group, the wireless communication terminals Q, R, and S use the received power information as transmission parameters. That is,
The transmission parameter from Q to P is L;
The transmission parameter from R to P is M;
The transmission parameter from S to P is N
And Or, let t be the current time and use a predetermined positive time constant K
The transmission parameter from Q to P is L exp (-K (tF));
The transmission parameter from R to P is M exp (−K (tG));
The transmission parameter from S to P is N exp (-K (tH))
It is.

  When this information is shared within the group and a packet is transmitted to the wireless communication terminal P outside the group, the wireless communication terminal having the maximum transmission parameter is used.

  The reception time and reception power at the time of Call Notification may be used instead of the reception time and reception power at the time of direct transmission.

  Hereinafter, the part which concerns on this technique among radio | wireless communication terminals is demonstrated in detail. FIG. 11 is a schematic diagram illustrating a schematic configuration of a wireless communication terminal according to the present technology. Hereinafter, a description will be given with reference to FIG.

  The wireless communication terminal 101 includes a reception unit 1101, an intra-group transmission unit 1102, an out-group transmission unit 1103, a storage unit 1104, a reception unit 1105, a received power processing unit 1106, a packet reception processing unit 1107, an out-group relay unit 1108, an intra-group relay unit A relay unit 1110 and an attenuation unit 1109 are provided.

  First, the reception unit 1101 receives an input of a packet in which a destination, a transmission source, and transmission information are specified.

  On the other hand, the intra-group transmission unit 1102 transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal that belongs to the same group as the wireless communication terminal 101.

  Further, the out-of-group transmission unit 1103 transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal that belongs to a group different from the wireless communication terminal 101.

Then, the intra-group relay unit 1110, when the destination of the received packet is another wireless communication terminal belonging to the same group as the wireless communication terminal 101,
(A) If the wireless communication terminal 101 is an upper station, the intra-group transmission unit 1102 transmits the packet to the other wireless communication terminal,
(B) If the wireless communication terminal 101 is a lower station, the intra-group transmission unit 1102 transmits the packet to the upper station of the group.

  On the other hand, the storage unit 1104 stores transmission parameters in association with candidate groups of external relay terminals and external destination terminals.

  Furthermore, the reception unit 1105 receives a packet transmitted from another wireless communication terminal.

  Then, when the transmission source of the received packet is another wireless communication terminal belonging to a group different from that of the wireless communication terminal 101, the reception power processing unit 1106 uses the wireless communication terminal 101 as an external relay terminal. The candidate group having the wireless communication terminal as the external destination terminal is associated with the received power of the packet as a transmission parameter and stored in the storage unit 1104, and the wireless communication terminal 101 is set as the transmission source and the wireless communication terminal 101 is set as the transmission destination. Specify the upper station of the group to which it belongs, specify transmission information that specifies the wireless communication terminal 101 as an external relay terminal, the other wireless communication terminal as an external destination terminal, and the received power of the packet as a transmission parameter. The new packet to be received is received by the receiving unit 1101 as an input.

On the other hand, the packet reception processing unit 1107, when the received packet or the destination of the received packet is the wireless communication terminal 101,
(C) If the transmission information specified in the packet is another packet, the receiving unit 1101 accepts the other packet as input,
(D) When an external relay terminal, an external destination terminal, and a transmission parameter are specified in the transmission information specified in the packet, a candidate set of the specified external relay terminal and the specified external destination terminal The transmission parameters are associated with each other and stored in the storage unit 1104. If the wireless communication terminal 101 is an upper station, each of the lower stations belonging to the same group as the wireless communication terminal 101 that is not the source of the packet is sent to And the reception unit 1101 receives a new packet that designates the transmission information of the packet as the transmission information, with the wireless communication terminal 101 as a transmission source,
(E) In cases other than (c) and (d) above, the transmission information is output.

Furthermore, when the destination of the received packet is another wireless communication terminal belonging to a group different from the wireless communication terminal 101, the out-of-group relay unit 1108
(F) If the wireless communication terminal 101 is stored in the storage unit 1104 as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, The packet is transmitted to the other wireless communication terminal by the non-group transmission unit 1103,
(G) If other than the wireless communication terminal 101 is stored in the storage unit 1104 as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, The accepting unit 1101 accepts a new packet that designates the candidate external relay terminal having the maximum transmission parameter as a destination, the wireless communication terminal 101 as a source, and designates the packet as transmission information.

  On the other hand, the attenuation unit 1109 attenuates each of the transmission parameters stored in the storage unit 1104 over time. Typically, each time a predetermined unit time elapses, each transmission parameter stored in the storage unit 1104 is attenuated by multiplying it by a predetermined constant larger than 0 and smaller than 1. By such processing, it is possible to easily realize the calculation of multiplying L or the like by the above exp (-K (t-F)) or the like.

  Note that these units are realized by the CPU and RAM included in the wireless communication terminal 101 working together with a normal mobile communication unit.

  FIG. 12 is a flowchart showing a flow of control of communication processing executed by the wireless communication terminal according to the present embodiment. This will be described below with reference to this figure.

  In this flowchart, the wireless communication terminal 101 registers a packet in the accepting unit 1101 so as to spontaneously transmit the packet, or the receiving unit 1105 of the wireless communication terminal 101 receives a packet from another wireless communication terminal. The illustration of the processing to be performed is omitted.

  In the former case, the packet is registered in the reception queue, and in the latter case, the packet is registered in the reception queue and processed in a FIFO (First In First Out) format as necessary. This queue is constituted by a RAM or the like.

  When registering a packet in the reception queue, the reception power information of the packet is also registered.

  Further, since the processing by the attenuation unit 1109 is performed in parallel with the processing described below, this is also omitted from illustration.

  When this communication process is started, it is checked whether or not the reception queue is empty (step S1201). If it is not empty (step S1201; No), one packet is acquired from the reception queue (step S1202), and it is determined what the destination of the packet Z is (step S1203).

  When the destination of the packet Z is another wireless communication terminal belonging to the same group as the wireless communication terminal 101 (step S1203; other terminal in the group), it is determined whether or not the wireless communication terminal 101 is an upper station. Determination is made (step S1204).

  If it is an upper station (step S1204; Yes), the intra-group transmission unit 1102 transmits the packet Z to the other wireless communication terminal, that is, the lower station (step S1205), and the process returns to step S1201.

  On the other hand, if it is not the upper station (step S1204; No), the wireless communication terminal 101 is a lower station, and therefore the intra-group transmission unit 1102 transmits the packet Z to the upper station of the group (step S1206). ), The process returns to step S1201.

  In step S1206, when transmitting the packet Z = (the wireless communication terminal 101 / the lower station / X in the same group) to the upper station, the packet is transmitted to the upper station (the wireless communication terminal). Terminal 101 / upper station / Z) is registered, registered in the reception queue, and received by the reception unit 1101 as input, transmission to the higher station is realized.

  On the other hand, when the destination of the packet Z is the wireless communication terminal 101 (step S1203; self), the type of transmission information specified in the packet Z is checked (step S1207).

  If the transmission information is another packet (step S1207; other packet), that is, packets are nested such that Z = (V / the wireless communication terminal 101 / (W / X / Y)). If there is, the other packet (W / X / Y) specified in the transmission information is registered in the reception queue (step S1208), and the process returns to step S1201.

  On the other hand, when the transmission information specifies an external relay terminal, an external destination terminal, and a transmission parameter (step S1207; transmission parameter, etc.), the specified external relay terminal and the specified external destination terminal The transmission parameter is associated with the candidate group and stored in the storage unit 1104 (step S1209).

  When the transmission parameter for the same candidate group is already stored in the storage unit 1104, the value is overwritten, and when the transmission parameter for the candidate group is not yet stored in the storage unit 1104, an addition is made. Then, the storage unit 1104 is updated.

  Further, it is checked whether or not the wireless communication terminal 101 is an upper station (step S1210). If it is not an upper station (step S1210; No), the process returns to step S1201.

  On the other hand, if it is an upper station (step S1210; Yes), each of lower stations belonging to the same group as the wireless communication terminal 101 that is not the source of the packet Z is set as the destination, and the wireless communication terminal 101 is set as the source. Then, the reception unit 1101 receives a new packet that specifies the transmission information of the packet Z as transmission information (step S1211), and the process returns to step S1201.

  As a result, information on transmission parameters and the like is transmitted to each lower station in the same group, and information on transmission parameters and the like is shared within the same group.

  On the other hand, if the transmission information is other than that (step S1207; other), the transmission information is output (step S1212), left to other processing, and the process returns to step S1201.

  When the destination of the packet Z is another wireless communication terminal belonging to a group different from that of the wireless communication terminal 101 (step S1203; another terminal in a different group), the other wireless communication terminal is stored in the storage unit 1104. Among candidate groups to be external destination terminals, search is made for those stored as the external relay terminal of the candidate group having the maximum transmission parameter (step S1213).

  Then, it is determined whether or not a candidate group of external relay terminals has been found by the search (step S1214). If no candidate group is found (step S1214; No), the packet Z is transmitted to the out-of-group transmission unit 1103 and the other radio. It transmits to a communication terminal (step S1215), and returns to step S1201.

  On the other hand, if it is found (step S1214; Yes), it is determined whether or not the external relay terminal of the candidate set of the search result is the wireless communication terminal 101 (step S1216). When that is right (step S1216; Yes), it progresses to step S1215.

  Otherwise (step S1216; No), a new packet (the wireless communication) that designates the external relay terminal of the candidate set of the search result as the destination, the wireless communication terminal 101 as the source, and designates the packet Z as transmission information. Terminal 101 / external relay terminal / Z of the search result candidate set) is added to the reception queue (step S1217), and the process returns to step S1201.

  On the other hand, if the reception queue is empty (step S1201; Yes), it is checked whether the reception queue is empty (step S1218). If the reception queue is not empty (step S1218; No), the packet and the packet are received from the reception queue. Received power at the time of reception is acquired (step S1219).

  Then, it is determined whether or not the source of the acquired packet Z is another wireless communication terminal belonging to a group different from that of the wireless communication terminal 101 (step S1220). Otherwise (step S1220; No), the process proceeds to step S1207.

  If so (step S1220; Yes), the wireless communication terminal 101 is designated as a transmission source, a higher-level station of the group to which the wireless communication terminal 101 belongs is designated as a destination, and the wireless communication terminal 101 is designated as an external relay terminal. The new wireless communication terminal is set as an external destination terminal, and a new packet specifying transmission information specifying the reception power of the packet Z as a transmission parameter is registered in the reception queue (step S1221), and the process proceeds to step S1207. .

  If such a new packet is registered in the reception queue, regardless of whether the wireless communication terminal 101 is an upper station or a lower station, transmission parameters are registered in step S1209, and the wireless communication terminal 101 If it is an upper station, the transmission parameter is transmitted to each lower station, and if the wireless communication terminal 101 is a lower station, the transmission parameter is transmitted to the upper station.

  On the other hand, when the reception queue is empty (step S1218; Yes), the process returns to step S1201. At this time, it is also possible to wait appropriately or return after executing other parallel processing.

  By performing such control, communication between groups is expected to be performed through a route that is assumed to have the highest transmission efficiency.

  Note that by loading a predetermined program into a programmable electronic circuit such as a DSP or FPGA, or a software radio having a CPU or the like, the DSP or FPGA is configured with the electronic circuit, or the CPU or the like is caused to execute the program. Accordingly, the wireless communication terminal may function.

  As described above, according to the present invention, in wireless communication that autonomously forms a group, a wireless communication terminal suitable for efficiently communicating with wireless communication terminals belonging to different groups, a wireless communication method, and , It is possible to provide a program for realizing these on a software radio.

It is a schematic diagram which shows schematic structure of the element which concerns on group formation of the radio | wireless communication terminal which concerns on embodiment of this invention. It is a flowchart which shows the flow of control of the operation mode transition process which changes the operation mode of a radio | wireless communication terminal. It is explanatory drawing which shows a mode that a radio | wireless communication terminal is mounted in a vehicle, mutually detects, and determines an operation mode. It is explanatory drawing which shows the result of the simulation experiment of a mode that a terminal group is comprised. It is a schematic diagram which shows the structure of the slot used for transmission of data information. It is explanatory drawing which shows a mode that transmission to the destination terminal which belongs to a different terminal group from a transmission origin terminal is performed. It is explanatory drawing which shows a mode that transmission to a destination terminal is performed via the relay terminal which is a high-order terminal of the destination terminal which belongs to a different terminal group from a transmission origin terminal. Transmission from a source terminal to a destination terminal via a relay terminal that is a higher order terminal of a destination terminal belonging to a different terminal group and a sub relay station that is a lower order terminal of this relay terminal It is explanatory drawing which shows. It is a graph which shows the experimental result of the relationship between the input traffic of the basic technology of this embodiment, and communication throughput. It is a graph which shows the experimental result of the relationship between the input traffic and communication delay of the basic technique of this embodiment. It is a schematic diagram which shows schematic structure of the element which concerns on communication of the radio | wireless communication terminal which concerns on this embodiment. It is a flowchart which shows the flow of control of the communication process performed with the radio | wireless communication terminal which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Wireless communication terminal 102 Initial detection part 103 Antenna 104 Low-order station mode setting part 105 Operation mode storage part 106 High-order terminal storage part 107 High-order station mode setting part 108 Low-order terminal registration part 109 Low-order terminal storage part 110 High-order station maintenance detection part 111 Low order Station maintenance detection unit 112 Undecided mode setting unit 113 Transmission unit 114 Reception unit 501 Slot 502 Control signal period 503 Data transfer period 1101 Reception unit 1102 In-group transmission unit 1103 Out-group transmission unit 1104 Storage unit 1105 Reception unit 1106 Received power processing unit 1107 Packet acceptance processing unit 1108 Outside-group relay unit 1109 Attenuating unit

Claims (5)

A wireless communication terminal that forms a group by becoming an upper station or a lower station, and each group includes one upper station and zero or more lower stations, and the wireless communication terminals belong to the same group or different groups. Communicate packets with other wireless communication terminals to which it belongs,
A reception unit that accepts input of a packet in which a destination, a source, and transmission information are specified;
An in-group transmission unit that transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal belonging to the same group as the wireless communication terminal;
An out-of-group transmission unit that transmits a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal belonging to a group different from the wireless communication terminal;
When the destination of the accepted packet is another wireless communication terminal belonging to the same group as the wireless communication terminal,
(A) If the wireless communication terminal is an upper station, the intra-group transmission unit transmits the packet to the other wireless communication terminal,
(B) If the wireless communication terminal is a lower station, an intra-group relay unit that causes the intra-group transmission unit to transmit the packet to an upper station of the group;
A storage unit for storing a transmission parameter in association with a candidate set of an external relay terminal and an external destination terminal;
A receiving unit for receiving a packet transmitted from another wireless communication terminal;
When the source of the received packet is another wireless communication terminal belonging to a group different from the wireless communication terminal, the wireless communication terminal is an external relay terminal, and the other wireless communication terminal is an external destination terminal. The received power of the packet is associated with a transmission parameter as a transmission parameter and stored in the storage unit, the wireless communication terminal is specified as a transmission source, and the upper station of the group to which the wireless communication terminal belongs is specified as a destination. Let the reception unit accept as input a new packet that specifies transmission information that specifies the wireless communication terminal as an external relay terminal, the other wireless communication terminal as an external destination terminal, and the reception power of the packet as a transmission parameter. Received power processing unit,
When the destination of the received packet or the received packet is the wireless communication terminal,
(C) If the transmission information specified in the packet is another packet, the reception unit accepts the other packet as input,
(D) When an external relay terminal, an external destination terminal, and a transmission parameter are specified in the transmission information specified in the packet, a candidate set of the specified external relay terminal and the specified external destination terminal If the wireless communication terminal is an upper station, the transmission parameters are associated with each other and stored in the storage unit, and each of the lower stations belonging to the same group as the wireless communication terminal is not the source of the packet, The reception unit accepts a new packet that designates the transmission information of the packet as transmission information with the wireless communication terminal as a source,
(E) In cases other than (c) and (d) above, a packet acceptance processing unit that outputs the transmission information,
When the destination of the accepted packet is another wireless communication terminal belonging to a group different from the wireless communication terminal,
(F) If the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, the packet Is transmitted to the other wireless communication terminal by the out-of-group transmission unit,
(G) If other than the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, Out-of-group relay unit that accepts a new packet that designates the packet as transmission information, the destination being the candidate external relay terminal with the maximum transmission parameter, the wireless communication terminal as a source ,
A wireless communication terminal comprising: an attenuation unit that attenuates each transmission parameter stored in the storage unit as time elapses . The wireless communication terminal according to claim 1 ,
The attenuation unit multiplies each transmission parameter stored in the storage unit by a predetermined constant larger than 0 and smaller than 1 every time a predetermined unit time elapses to attenuate the wireless communication terminal. . A wireless communication method executed by a wireless communication device that forms a group by becoming an upper station or a lower station, wherein one upper station and zero or more lower stations belong to each group, and the wireless communication terminal Communicates packets with other wireless communication terminals belonging to the same group or different groups, and the wireless communication apparatus stores a transmission parameter in association with a candidate set of an external relay terminal and an external destination terminal Part
An accepting step for accepting an input of a packet in which a destination, a source, and transmission information are specified;
An intra-group transmission step of transmitting a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal belonging to the same group as the wireless communication terminal;
An out-group transmission step of transmitting a packet in which a destination, a transmission source, and transmission information are specified to another wireless communication terminal belonging to a group different from the wireless communication terminal;
When the destination of the accepted packet is another wireless communication terminal belonging to the same group as the wireless communication terminal,
(A) If the wireless communication terminal is an upper station, in the intra-group transmission step, the packet is transmitted to the other wireless communication terminal,
(B) If the wireless communication terminal is a lower station, an intra-group relay step of transmitting the packet to an upper station of the group in the intra-group transmission step;
A receiving step of receiving a packet transmitted from another wireless communication terminal;
When the source of the received packet is another wireless communication terminal belonging to a group different from the wireless communication terminal, the wireless communication terminal is an external relay terminal, and the other wireless communication terminal is an external destination terminal. The received power of the packet is associated with a transmission parameter as a transmission parameter and stored in the storage unit, the wireless communication terminal is specified as a transmission source, and the upper station of the group to which the wireless communication terminal belongs is specified as a destination. A new packet that specifies transmission information that specifies a wireless communication terminal as an external relay terminal, the other wireless communication terminal as an external destination terminal, and the reception power of the packet as a transmission parameter is input to the reception step as an input. Received power processing process,
When the destination of the received packet or the received packet is the wireless communication terminal,
(C) When the transmission information specified in the packet is another packet, the other packet is received as an input in the receiving step,
(D) When an external relay terminal, an external destination terminal, and a transmission parameter are specified in the transmission information specified in the packet, a candidate set of the specified external relay terminal and the specified external destination terminal If the wireless communication terminal is an upper station, the transmission parameters are associated with each other and stored in the storage unit, and each of the lower stations belonging to the same group as the wireless communication terminal is not the source of the packet, The reception step accepts a new packet that designates the transmission information of the packet as transmission information with the wireless communication terminal as a source,
(E) Packet reception processing step for outputting the transmission information in cases other than (c) and (d) above,
When the destination of the accepted packet is another wireless communication terminal belonging to a group different from the wireless communication terminal,
(F) If the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, the packet Is transmitted to the other wireless communication terminal in the out-of-group transmission step,
(G) If other than the wireless communication terminal is stored in the storage unit as an external relay terminal of a candidate set having the maximum transmission parameter among candidate sets having the other wireless communication terminal as an external destination terminal, Out-of-group relay process in which the receiving process accepts a new packet that has a candidate set of external relay terminals with the largest transmission parameter as a destination, the wireless communication terminal as a source, and designates the packet as transmission information ;
A wireless communication method comprising: an attenuation step of attenuating each of transmission parameters stored in the storage unit over time . The wireless communication method according to claim 3 ,
In the attenuation step, each time a predetermined unit time elapses, each transmission parameter stored in the storage unit is multiplied by a predetermined constant larger than 0 and smaller than 1, and is attenuated. . A program causing a software radio to function as each unit of the wireless communication terminal according to claim 1 or 2 .

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