JP5815334B2 - Transmitting apparatus, communication system, communication condition determining method, and communication condition determining program - Google Patents

Description

  The present invention relates to a transmission device, a communication system, a communication condition determination method, and a communication condition determination program. The present invention relates to a transmission apparatus such as a wireless LAN terminal suitable for saving power consumption at the time of transmission, a communication system, or a communication condition determination method and a communication condition determination program that can be suitably used for these.

  In this specification, a wireless LAN slave device comprising various communication terminals such as a wireless LAN master device serving as an access point of a wireless LAN (Local Area Network) and a mobile terminal that performs communication by wireless LAN through the wireless LAN master device is described. These are collectively referred to as wireless LAN terminals.

  The wireless LAN terminal includes a wireless circuit that amplifies a weak signal at the time of wireless transmission on both the parent device side and the child device side. Such wireless circuits consume more power than other common electronic circuits. Therefore, in the case of a portable wireless LAN terminal that is often driven by a secondary battery, how to reduce power consumption is an important issue in product development in order to extend the operating time. On the other hand, if the transmission power of the transmission device is insufficient as a result of saving power consumption, the quality of communication cannot be ensured.

  Therefore, in the related art of the present invention, the value related to the noise component included in the carrier wave of the received signal is compared with a plurality of reference values to determine whether or not the wireless communication situation is good. Then, it has been proposed to lower or increase the level of transmission power according to the environment in which communication is performed (see, for example, Patent Document 1).

  With this related technology, when it is determined that the state of wireless communication is “good”, the power consumption is reduced by referring to the power table prepared in advance to reduce the transmission power to the extent that the communication rate does not decrease. I have to. Further, when the state in which wireless communication is performed is determined to be “medium”, the transmission power is increased from the first level in order to achieve a good balance between securing a predetermined communication rate and suppressing power consumption.

Japanese Patent Laying-Open No. 2008-211161 (paragraphs 0042 to 0047, FIG. 1)

  However, in this related technology, when the situation of performing wireless communication becomes worse, the communication rate itself is reduced in relation to power consumption, and relatively large capacity data or data that requires real-time performance is required. In some cases, it was not suitable for communication.

  Accordingly, an object of the present invention is to provide a transmission apparatus, a communication system, and a communication condition determination method capable of satisfying a communication request for both a communication rate and a transmission output and avoiding wasteful power consumption within a range satisfying the request. And providing a communication condition determination program.

  In the present invention, (b) a communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions, and (b) the communication described above prior to communication with the communication partner. Communication condition initial selection means for selecting one combination having a high possibility of successful communication from the table as an initial communication condition; and (c) transmission for transmitting a signal to the communication partner described above under one specified communication condition. Means, (d) a response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmitting means, and (e) the response receiving means. A communication environment determining means for determining the communication environment with the communication partner according to the received response status; and (f) the communication condition selected by the communication condition initial selecting means as the first Then, according to the determination result of the communication environment determination means for the communication condition adopted for the transmission of the transmission means, the transmission is performed from the communication table along the direction in which the communication rate increases or the transmission output decreases. A communication condition revision means for selecting a revised communication condition to be used for (1) selecting the next communication condition revised by the communication condition revision means according to the determination result of the communication environment determination means, The transmission apparatus includes communication condition determining means for determining whether to hold the communication condition.

  In the present invention, (a) a communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as a communication condition, and the communication table described before communication with the communication partner described above. Communication condition initial selection means for selecting one combination having a high possibility of successful communication as an initial communication condition, transmission means for transmitting a signal to the communication partner described above under one specified communication condition, and When there is a response indicating successful reception from the communication partner that has received the signal transmitted by the transmission unit, a response reception unit that receives the response, and the communication described above according to the response status received by the response reception unit The communication environment determination means for determining the communication environment with the other party, and the transmission means selected from the communication condition initial selection means described above as the first transmission condition. The revised communication condition used for transmission along the direction in which the communication rate increases or the transmission output decreases from the communication table according to the determination result of the communication environment determination means with respect to the communication condition adopted in FIG. Communication condition revision means for selecting the communication, and communication for judging whether to select the next revised communication condition by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means (B) a receiving means for receiving a signal sent from the transmitting means of the transmitting apparatus, and reception of the signal when the signal is successfully received by the receiving means. The communication system includes a receiving device including a response unit that makes a response indicating success.

  Furthermore, in the present invention, (b) the communication table described above prior to communication with the communication partner described above, out of the communication tables in which a plurality of combinations of communication rates and transmission outputs when communicating with the communication partner are defined as communication conditions. A communication condition initial selection step for selecting one combination having a high possibility of successful communication as an initial communication condition; (b) a transmission step for transmitting a signal to the communication partner described above under one communication condition; C) a response reception step for receiving a response indicating successful reception from the communication partner receiving the signal transmitted in this transmission step; and (d) a response status received in this response reception step. A communication environment determination step of determining a communication environment with the communication partner according to the above, and (e) the communication condition initial selection step described above The direction in which the communication rate increases or the transmission output decreases from the communication table according to the determination result in the communication environment determination step with respect to the communication condition adopted for the transmission in the transmission step starting from the selected communication condition The communication condition revision step for selecting the revised communication condition to be used for transmission along the direction of transmission and the next revision using the communication condition revision step according to the determination result in (f) the communication environment determination step. The communication condition determination method includes a communication condition determination step for determining whether to select a communication condition or to maintain a current communication condition.

  Furthermore, in the present invention, as a communication condition determination program, (a) a communication partner described above from a communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions. Communication condition initial selection processing for selecting, as an initial communication condition, one combination that is likely to succeed in communication from the communication table described above prior to communication with (ii) the communication partner described above under one communication condition (C) a response reception process for receiving a response indicating a successful reception from the communication partner receiving the signal transmitted in the transmission process; A communication environment determination process for determining the communication environment with the communication partner according to the response status received by the response reception process; The communication rate is increased from the communication table according to the determination result by the communication environment determination process for the communication condition adopted for transmission by the transmission process starting from the communication condition selected by the communication condition initial selection process. A communication condition revision process for selecting a revised communication condition to be used for transmission along a direction or a direction in which the transmission output decreases, and (f) the communication condition revision process described above according to the determination result by the communication environment determination process. And a communication condition determination process for determining whether to select the next revised communication condition or to keep the current communication condition.

  As described above, according to the present invention, a plurality of combinations of both the communication rate and the transmission output used when the transmission device communicates with the reception device are stored as communication conditions in the communication table. did. Therefore, it is possible to select appropriate communication conditions from various viewpoints such as power saving and securing a communication rate according to the determination result of the communication environment from the plurality of communication conditions.

It is a claim corresponding | compatible figure of the transmitter of this invention. It is a claim corresponding | compatible figure of the communication system of this invention. It is a claim corresponding | compatible figure of the communication condition determination method of this invention. It is a claim corresponding | compatible figure of the communication condition determination program of this invention. 1 is a system configuration diagram showing an outline of a wireless LAN communication system in an embodiment of the present invention. It is a block diagram showing the outline | summary of the structure of the wireless LAN main | base station used by this Embodiment. It is explanatory drawing showing an example of the content of the transmission output setting table used by this Embodiment. 6 is a flowchart specifically showing a part of packet transmission processing for a wireless LAN slave device by the wireless LAN master device of the present embodiment. FIG. 9 is a flowchart specifically illustrating a communication rate determination process in the process of FIG. 8. FIG. 9 is a flowchart showing the subsequent processing of the wireless LAN base unit based on the transmission of the packet signal described in the processing of FIG. 8. It is a block diagram showing the structure of the wireless LAN main | base station in the wireless LAN communication system of the 1st modification of this invention. It is a flowchart showing the principal part of the transmission process of the packet signal of the wireless LAN base unit in a 1st modification. It is a block diagram showing the structure of the wireless LAN main | base station in the wireless LAN communication system of the 2nd modification of this invention. It is a flowchart showing the principal part of the transmission process of the packet signal of the wireless LAN main unit in a 2nd modification. It is a block diagram showing the structure of the wireless LAN base unit in the wireless LAN communication system of the 3rd modification of this invention. It is the flowchart which showed the principal part of the calibration process of the transmission power reduction threshold value with the change of the communication environment by the wireless LAN main | base station of a 3rd modification, and a transmission output increase threshold value. It is explanatory drawing which showed an example of the table for favorable communication environments in a 3rd modification. It is explanatory drawing which showed an example of the table for poor communication environments in a 3rd modification.

  FIG. 1 is a diagram corresponding to claims of the transmitting apparatus of the present invention. The transmission apparatus 10 of the present invention includes a communication table 11, a communication condition initial selection unit 12, a transmission unit 13, a response reception unit 14, a communication environment determination unit 15, a communication condition revision unit 16, and a communication condition determination unit. 17 is provided. Here, the communication table 11 defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions. The communication condition initial selection means 12 selects, as an initial communication condition, one combination that is likely to be successfully communicated from the communication table 11 prior to communication with the communication partner. The transmission means 13 transmits a signal to the communication partner described above under one specified communication condition. The response receiving unit 14 receives a response indicating successful reception from the communication partner that has received the signal transmitted by the transmission unit 13. The communication environment determining unit 15 determines the communication environment with the communication partner described above according to the response status received by the response receiving unit 14. The communication condition revision means 16 described above from the communication table 11 according to the determination result of the communication environment determination means 15 for the communication condition adopted for the transmission of the transmission means 13 with the communication condition selected by the communication condition initial selection means 12 as the first. A revised communication condition used for transmission is selected along the direction in which the communication rate increases or the transmission output decreases. The communication condition determination unit 17 determines whether to select the next communication condition revised by the communication condition revision unit 16 or to hold the current communication condition according to the determination result of the communication environment determination unit 15.

  FIG. 2 is a diagram corresponding to the claims of the communication system of the present invention. The communication system 20 of the present invention includes a transmission device 21 and a reception device 22. Here, the transmission device 21 includes a communication table 21a, a communication condition initial selection unit 21b, a transmission unit 21c, a response reception unit 21d, a communication environment determination unit 21e, a communication condition revision unit 21f, and a communication condition determination unit. 21g is provided. The communication table 21a defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions. The communication condition initial selection means 21b selects, as an initial communication condition, one combination having a high possibility of successful communication from the communication table 21a prior to communication with the communication partner. The transmission means 21c transmits a signal to the communication partner described above under one specified communication condition. The response receiving unit 21d receives a response indicating successful reception from the communication partner that has received the signal transmitted by the transmission unit 21c. The communication environment determination unit 21e determines the communication environment with the communication partner described above according to the response status received by the response reception unit 21d. The communication condition revision unit 21f described above from the communication table 21a according to the determination result of the communication environment determination unit 21e with respect to the communication condition adopted for the transmission of the transmission unit 21c starting with the communication condition selected by the communication condition initial selection unit 21b. A revised communication condition used for transmission is selected along the direction in which the communication rate increases or the transmission output decreases. The communication condition determination unit 21g determines whether to select the next revised communication condition by the communication condition revision unit 21f or to keep the current communication condition according to the determination result of the communication environment determination unit 21e. The receiving device 22 includes a receiving unit 22a and a response unit 22b. The receiving unit 22a receives a signal transmitted from the transmitting unit 21c of the transmitting device 21. The reply means 22b makes a reply indicating the above-described successful reception when the reception means 22a successfully receives the signal.

  FIG. 3 is a diagram corresponding to claims of the communication condition determination method of the present invention. The communication condition determination method 30 of the present invention includes a communication condition initial selection step 31, a transmission step 32, a response reception step 33, a communication environment determination step 34, a communication condition revision step 35, and a communication condition determination step 36. ing. Here, in the communication condition initial selection step 31, prior to the communication with the communication partner described above from the communication table in which a plurality of combinations of the communication rate and the transmission output when communicating with the communication partner are defined as the communication condition. One combination having a high possibility of successful communication is selected as an initial communication condition from the communication table. In the transmission step 32, a signal is transmitted to the communication partner described above under one communication condition. In the response reception step 33, when there is a response indicating successful reception from the communication partner that has received the signal transmitted in the transmission step 32, this is received. In the communication environment determining step 34, the communication environment with the communication partner is determined according to the response status received in the response receiving step 33. In the communication condition revision step 35, the communication condition selected in the communication condition initial selection step 31 is set as the first, and the communication table is selected from the communication table according to the determination result in the communication environment determination step 34 for the communication condition adopted for the transmission in the transmission step 32. The revised communication condition used for transmission is selected along the direction in which the communication rate increases or the transmission output decreases. In the communication condition determination step 36, it is determined whether the next revised communication condition is selected or the current communication condition is maintained using the communication condition revision step 35 according to the judgment result in the communication environment judgment step 34.

  FIG. 4 shows a claim correspondence diagram of the communication condition determination program of the present invention. The communication condition determination program 40 according to the present invention includes a computer that performs communication condition initial selection processing 41, transmission processing 42, response reception processing 43, communication environment determination processing 44, communication condition revision processing 45, and communication condition determination processing. 46 is executed. Here, in the communication condition initial selection process 41, prior to communication with the communication partner described above from the communication table in which a plurality of combinations of communication rates and transmission outputs when communicating with the communication partner are defined as communication conditions. One combination having a high possibility of successful communication is selected as an initial communication condition from the communication table. In the transmission process 42, a signal is transmitted to the communication partner described above under one communication condition. In the response reception process 43, when there is a response indicating successful reception from the communication partner that has received the signal transmitted in the transmission process 42, this is received. In the communication environment determination process 44, the communication environment with the communication partner is determined according to the response status received by the response reception process 43. In the communication condition revision process 45, the communication condition selected from the communication table is selected from the communication table according to the determination result by the communication environment determination process 44 for the communication condition adopted for transmission by the transmission process 42 with the communication condition selected by the communication condition initial selection process 41 as the first. The revised communication condition used for transmission is selected along the direction in which the communication rate increases or the transmission output decreases. In the communication condition determination process 46, it is determined whether to select the next revised communication condition or to keep the current communication condition using the communication condition revision process 45 according to the discrimination result of the communication environment discrimination process 44.

  <Embodiment of the Invention>

  Next, an embodiment of the present invention will be described.

  FIG. 5 shows an outline of the wireless LAN communication system according to the embodiment of the present invention. The wireless LAN communication system 100 includes a wireless LAN master device 101 as an access point and a wireless LAN slave device 102 that communicates with the wireless LAN master device 101 wirelessly. This figure shows the simplest example in which one wireless LAN slave device 102 exists in an area where the wireless LAN master device 101 exists. There may be a case where there are a plurality of wireless LAN slave devices 102 relative to the wireless LAN master device 101. Also, there may be a plurality of wireless LAN base units 101 so as to be close to each other.

In the wireless LAN communication system 100, the wireless LAN base unit 101 can set the transmission output in a plurality of stages. When the transmission output is the smallest, the wireless LAN master device 101 can communicate only with the wireless LAN slave device 102 existing in the first communicable area 111 ₁ as the inside of the circle indicated by the solid line. When the transmission power of the radio LAN base unit 101 is one step larger, also communicates with the wireless LAN terminal 102 exists in ₂ inside the donut-shaped second communicable area 111 of the circle shown by a broken line outside the circle indicated by a solid line be able to. Of course, the wireless LAN base unit 101 in this case can communicate with the wireless LAN terminal 102 which exists in _one first service area 111, waste occurs in the transmission output.

  In the wireless LAN communication system 100 of the present embodiment, the wireless transmission output is controlled by the communication rate at the time of wireless communication and the RSSI (Received Signal Strength Indicator) value at the time of reception. Thereby, the power consumption of the wireless circuit that performs transmission is reduced. In addition, by controlling the wireless transmission output, the communicable area is prevented from expanding more than necessary, and interference with other wireless communications sharing the same channel can be suppressed.

  In the wireless LAN communication system 100 of the present embodiment described below, the wireless LAN master device 101 and the wireless LAN slave device 102 each have a 2.4 GHz band IEEE (The Institute of Electrical and Electronics Engineers, Inc.) 802. The description will be made assuming that it corresponds to 11n. IEEE802.11n is a specification for performing communication at a maximum of 600 Mbps (bits / second) with a radio of 2.4 GHz band or 5 GHz band. Both the wireless LAN master device 101 and the wireless LAN slave device 102 can change the output of the wireless circuit for switching the communicable area. However, in this embodiment, only the wireless LAN master device 101 is used to simplify the explanation. Will be described as having the function.

  FIG. 6 shows an outline of the configuration of the wireless LAN base unit. The wireless LAN base device 101 includes a wireless unit 121 including a wireless circuit that transmits and receives packet signals. The wireless unit 121 is connected to a communication rate determining unit 122 that determines a communication rate, a transmission output determining unit 123 that determines a transmission output, and an over-threshold acknowledge counter unit 124.

  The threshold value exceeding acknowledge counter unit 124 counts packets having a communication rate at which the wireless LAN base unit 101 has successfully communicated. Packets to be counted have a communication rate that is less than the transmission output reduction threshold or greater than the transmission output increase threshold. Here, the “transmission output reduction threshold” is set to a higher communication rate that reduces the transmission output when the wireless LAN base unit 101 communicates with the wireless LAN handset 102. When the number of packets exceeding the “transmission output reduction threshold” exceeds a specified value because the set communication rate is high, control for reducing the transmission output is performed.

  On the other hand, the “transmission output increase threshold” is set to a lower communication rate that increases the transmission output when the wireless LAN base unit 101 communicates with the wireless LAN handset 102. When the number of packets exceeding the “transmission output increase threshold” exceeds a specified value because the set communication rate is low, control to increase the transmission output is performed.

  Whether or not the packet communication is successful can be determined by whether or not an acknowledge response is obtained from the receiving side of the packet signal. In order to count packets, the threshold value exceeding acknowledge counter unit 124 includes a transmission output reduction threshold number counter 125 and a transmission output increase threshold number counter 126. The transmission output determining unit 123 refers to the transmission output setting table in the transmission output setting table unit 127 when setting the transmission output.

  Such a wireless LAN base device 101 includes a control unit 130 including a CPU (Central Processing Unit) 128 and a memory 129 such as a ROM (Read Only Memory) storing a program executed by the CPU 128. At least a part of each unit such as the communication rate determining unit 122 constituting the wireless LAN base device 101 may be realized by software by the CPU 128 executing a program stored in the memory 129. .

  FIG. 7 shows an example of the contents of the transmission output setting table. This will be described with reference to FIGS.

  The transmission output setting table 127T stored in the transmission output setting table unit 127 includes a communication rate, a communication rate classification, an MCS (Modulation and Modulation and) when the wireless LAN base unit 101 transmits a data packet to the wireless LAN handset 102. Three levels of transmission output are specified for each combination of (Coding Scheme). Here, the three-stage transmission output (mW / MHz) is “small output value” as the smallest output value, “medium output value” as the next largest output value, and “maximum output value” as the maximum output value. Value ". The division of the transmission output does not need to be in three stages, and may be more or less than this, but in the present embodiment, there are three stages.

  “Communication rate (Mbps)” has a minimum communication rate of 1 Mbps. The lowest communication rate of 1 Mbps is also used for a management packet for securing a wireless LAN connection. Therefore, the lowest communication rate in the present embodiment is the same value as the communication rate of the management packet in all transmission output settings. Of course, the lowest communication rate may be set to a value different from the communication rate of the management packet.

  “Communication rate classification” indicates three types of IEEE 802.11b, IEEE 802.11g, and IEEE 802.11n, and the number of streams for IEEE 802.11n. The HT 20 performs communication at 20 MHz for one channel, and the HT 40 performs communication at a 40 MHz width for two channels. The number of streams is the number of spatially multiplexed signals by MIMO (Multi Input Multi Output).

  The “MCS” used varies depending on the number of streams during wireless communication. When the number of streams is “1” when the MCS is “0” to “7”, when the number of streams is “2” when the MCS is “8” to “15”, the MCS is “16” to “23”. ”Is when the number of streams is“ 3 ”, and when the MCS is“ 24 ”to“ 31 ”, the number of streams is“ 4 ”. However, in the wireless LAN communication system of the present embodiment, as shown in FIG. 7, since the number of streams is “1” and “2”, the MCS is from “0” to “15”. ing. Of course, the wireless LAN communication system may use MCS from “0” to “31”.

  In the table shown in FIG. 7, symbols indicated by white triangles indicate communication rates that serve as transmission output reduction thresholds. By setting the “transmission output reduction threshold”, it is possible to reduce transmission power while maintaining a communication rate of a certain level or higher. Of course, as the transmission power decreases, the communicable area in which a communication rate of a certain level or more can be secured decreases. Symbols indicated by black triangles indicate a communication rate that is a transmission output increase threshold.

Now, assume that the wireless LAN base device 101 shown in FIG. 5 is communicating with the connected wireless LAN slave device 102 with the maximum output value in the transmission output shown in the transmission output setting table 127T of FIG. At this time, it is assumed that the wireless LAN slave device 102 is located in the _first communicable area 1111 as shown in FIG.

  The wireless LAN master device 101 transmits to the wireless LAN slave device 102 at a communication rate equal to or higher than the communication rate that is the transmission output reduction threshold, and the wireless LAN slave device 102 has successfully received more than the specified number of packets in this communication Assume that each acknowledge response is returned. In this case, there is a margin in the transmission output performed by the wireless LAN base unit 101. Therefore, the next time the wireless LAN base unit 101 performs transmission to the wireless LAN handset 102, the medium output value that is set to a transmission output that is one step lower than the maximum output value is applied.

In this way, the wireless LAN base unit 101 communicates with the wireless LAN handset 102 while maintaining a communication rate higher than a certain level, checks the state of an acknowledge response, and transmits the transmission power according to the result. Can be reduced. In this example, the size of the communicable area of the wireless LAN base device 101 is reduced from the _second communicable area 111 ₂ to the first communicable area 111 ₁ while maintaining the communication rate. Therefore, when the wireless LAN slave device 102 is located in the _first communicable area 1111, as shown in FIG. 5, the transmission power of the wireless LAN master device 101 can be reduced.

  As described above, in the wireless LAN communication system 100 according to the present embodiment, when the transmission output is controlled, special communication for measuring the line quality is unnecessary. For this reason, the problem of band compression does not occur.

  FIG. 8 specifically shows a part of packet transmission processing to the wireless LAN slave device by the wireless LAN master device. This will be described with reference to FIGS.

  When the timing for starting packet transmission to the wireless LAN slave unit 102 arrives (step S201: Y), the wireless LAN base unit 101 determines one communication rate from the communication rates that can be used by the communication rate determination unit 122. (Step S202). The determined communication rate is notified to the wireless unit 121 and the transmission output determining unit 123.

  The transmission output determining unit 123 refers to the transmission output setting table unit 127 based on the determined communication rate, and determines the transmission output of the wireless LAN base unit 101 from the relationship with the setting contents of the currently operating transmission output ( Step S203). For example, it is assumed that the currently set transmission output is “medium output value” shown in FIG. 7 and the communication rate is 40.5 Mbps (11n HT40 1stream MCS2). In this case, the transmission output is determined to be 7 (mW / MHz).

  The control unit 130 of the wireless LAN base device 101 determines whether the communication rate determined in step S202 is less than the transmission output increase threshold (step S204). In this example, the communication rate is 40.5 Mbps, and the transmission output increase threshold at the “medium output value” is 6 Mbps from FIG. Therefore, the communication rate determined in step S202 is not less than the transmission output increase threshold (step S204: N).

  In this case, the control unit 130 determines whether or not the communication rate determined in step S202 is equal to or higher than the transmission output reduction threshold (step S205). In FIG. 7, the transmission output reduction threshold value in the “medium output value” is 104 Mbps. Therefore, the communication rate of 40.5 Mbps is not more than 104 Mbps as the transmission output reduction threshold (N). Therefore, the control unit 130 transmits a packet signal with the communication rate determined in step S202 and the transmission output determined by the transmission output determination unit 123 (step S206).

  Thereafter, the wireless LAN base device 101 waits for an acknowledgment response from the wireless LAN slave device 102 (step S207). If the wireless LAN base unit 101 normally receives the packet signal transmitted by the wireless LAN base unit 101 in step S206, an acknowledge signal is returned to the wireless LAN base unit 101 within a predetermined time. On the other hand, when the wireless LAN slave unit 102 fails to receive the packet signal, the acknowledge signal is not returned.

  If there is an acknowledge response from the wireless LAN slave device 102 (step S207: Y), the wireless LAN master device 101 notifies the threshold counter acknowledge counter unit 124 that the communication with the wireless LAN slave device 102 has succeeded (step S208). ). Thereby, the packet transmission processing by the wireless LAN base unit 101 ends (end).

  In this example, when an acknowledge response is not returned from the wireless LAN slave device 102 within a predetermined time (step S207: N), the wireless LAN master device 101 performs a packet signal retransmission process. The wireless unit 121 of the wireless LAN base device 101 determines whether this retransmission processing has exceeded a predetermined upper limit number (step S209). If not exceeded (N), the wireless unit 121 causes the communication rate determining unit 122 to select a communication rate that is one step lower than the current rate from the available communication rates (step S202). In this example, since the IEEE 802.11n communication is performed, the communication rate is changed from 40.5 Mbps to 39 Mbps. Then, retransmission of the packet signal to the wireless LAN slave unit 102 is attempted by the processing after step S203.

  Assuming that such retransmission processing of the packet signal is repeated within a failure, it is finally determined in step S209 that the wireless unit 121 has exceeded the upper limit number of retransmissions (Y). In this case, the wireless unit 121 of the wireless LAN master device 101 discards the packet signal that was scheduled to be transmitted to the wireless LAN slave device 102 (step S210). In this case, the packet transmission process by the wireless LAN base unit 101 ends in an unsuccessful state (end).

  FIG. 9 specifically shows the communication rate determination process in FIG. This will be described with reference to FIGS.

  When the packet transmission process is started, the control unit 130 of the wireless LAN base device 101 determines whether this is a new packet transmission (step S221). When new packet transmission is performed with the wireless LAN slave unit 102 (Y), a new communication rate is determined according to the communication status (step S222), and the communication rate determination process is terminated. (End)

  If it is not a new packet transmission (step S221: N), it is determined whether the rate of successful communication with the wireless LAN slave device 102 at the communication rate set up to the previous time (the rate at which the acknowledgment is returned) is greater than or equal to the specified value. Check (step S223). For example, assume that communication is successful for 50 packets out of 100 packets with a communication rate of 40.5 Mbps. In this case, the control unit 130 checks whether the communication rate that is one higher than the previous packet transmission rate can be selected in the table shown in FIG. 7 (step S224).

  In this example, since the wireless LAN handset 102 supports IEEE802.11n communication, a communication rate of 52 Mbps, which is one higher than the communication rate of 40.5 Mbps, exists and can be selected (step S224: Y). Therefore, the next higher communication rate of 52 Mbps is determined (step S225), and the process ends (end).

  On the other hand, with the communication rate set to 40.5 Mbps, the number of packets that can be statistically checked for the rate of successful packets is not transmitted, or the rate of successful communication is specified. If the value has not been reached (step S223: N), the currently set communication rate is determined (step S226), and the process ends (end). Even if the communication rate one level above does not exist in the table shown in FIG. 7 in step S224 (N), the currently set communication rate is similarly determined (step S226), and the process ends (end).

  As described above, when there is a margin in the transmission output of the packet, the communication speed is increased within a selectable range by the processing shown in FIG. As a result, the wireless LAN base unit 101 can shorten the communication time with the wireless LAN handset 102 and suppress power consumption during communication.

  Next, returning to FIG. 8, when the communication rate initially determined in step S202 is less than the transmission output increase threshold in the determination in step S204, the communication rate is reduced in step S205. A case where the result of comparison with the threshold value is equal to or greater than the transmission output increase threshold value will be described.

  First, when the communication rate initially determined in step S202 is less than the transmission output increase threshold value in the determination in step S204 (Y), the control unit 130 determines the determined communication rate and its communication. A threshold exceeding acknowledge counter unit 124 is notified that the rate is less than the transmission output increase threshold (step S211). The wireless unit 121 transmits a packet signal at this communication rate and transmission output (step S212).

  On the other hand, if the result of comparing the communication rate with the transmission output reduction threshold in step S205 is greater than or equal to the transmission output increase threshold (Y), the control unit 130 determines that the determined communication rate and the communication rate is greater than or equal to the transmission output reduction threshold. It is notified to the acknowledge counter unit 124 that the threshold value has been exceeded (step S213). In this case, the wireless unit 121 transmits a packet signal at this communication rate and transmission output (step S214).

  FIG. 10 shows the subsequent processing of the wireless LAN base unit based on the transmission of the packet signal described in FIG. This will be described with reference to FIGS.

  First, a case where the wireless LAN base unit 101 transmits a packet signal in step S212 in FIG. 8 will be described. In this example, the communication rate is less than the transmission output increase threshold, and is a low value that increases the transmission output.

  After sending the packet signal, the wireless LAN base device 101 waits for an acknowledge response from the wireless LAN slave device 102 (step S241). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN master device 101 notifies the acknowledge counter counter 124 that the communication with the wireless LAN slave device 102 has succeeded (step S242). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124 increases the transmission output increase threshold number as the count value of the transmission output increase threshold number counter 126 by “1” (step S243). The initial value of the count value of the transmission output increase threshold number counter 126 is “0”, and the count value is increased by “1” every time the communication success notification is received in step S242.

  The threshold value exceeding acknowledge counter unit 124 determines whether or not the count value of the transmission output increase threshold number counter 126 exceeds a predetermined value set in advance for the transmission output increase threshold number (step S244). The specified value determined for the transmission output increase threshold number is, for example, 30 (times).

  If the count value of the transmission output increase threshold number counter 126 exceeds the specified value as a result of the successful transmission of the packet signal (Y), the threshold excess acknowledge counter unit 124 transmits to the transmission output determination unit 123. The change of the output setting to the high output side is notified (step S245). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124 are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101 is performed. Will end (end).

  With the above processing, the transmission output of the packet increases, so that the communication is performed more stably at the initially set lower communication rate. As a result, the communication rate can be increased to a possible range by the communication rate determination process described in FIG. In this way, communication between the wireless LAN master device 101 and the wireless LAN slave device 102 is optimized, and efficient communication becomes possible.

  On the other hand, if the count value of the transmission output increase threshold number counter 126 after counting up in step S244 does not exceed a predetermined value (N), the wireless LAN is performed without performing the process described in step S245. The packet transmission process by the base unit 101 ends (END). If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S241 (N), the process proceeds to step S202 in FIG. 8, and a low-speed communication rate is obtained by the process omitted in FIG. The packet retransmission processing is performed as processing after step S203 at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded (step S210), and the packet transmission process by the wireless LAN base unit 101 ends (end).

  Finally, a case where the wireless LAN base unit 101 transmits a packet signal in step S214 of FIG. 8 will be described. In this example, the communication rate is equal to or higher than the transmission output reduction threshold, and is a higher value that will reduce the transmission output.

  After transmitting the packet signal, the wireless LAN base device 101 waits for an acknowledge response from the wireless LAN slave device 102 (step S247). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN master device 101 notifies the threshold counter acknowledge counter unit 124 that the communication with the wireless LAN slave device 102 has been successful (step S248). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124 increases the transmission output reduction threshold number as the count value of the transmission output reduction threshold number counter 125 by “1” (step S249). The initial value of the count value of the transmission output reduction threshold number counter 125 is “0”, and the count value is incremented by “1” each time the communication success notification in step S248 is received.

  The threshold value exceeding acknowledge counter unit 124 determines whether or not the count value of the transmission output reduction threshold number counter 125 exceeds a predetermined value determined in advance for the transmission output reduction threshold number (step S250). The specified value determined for the number of transmission output reduction thresholds is, for example, 50 (times). If the count value of the transmission output reduction threshold number counter 125 exceeds the specified value (Y) as a result of continuous transmission of the packet signal, the threshold excess acknowledge counter unit 124 transmits to the transmission output determination unit 123. The change of the output setting to the low output side is notified (step S251). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124 are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101 is performed. Will end (end).

  As a result of the above processing, the packet transmission output decreases, so that communication between the wireless LAN master device 101 and the wireless LAN slave device 102 is performed with reduced power consumption.

  If the count value of the transmission output reduction threshold number counter 125 after counting up in step S250 has not exceeded a predetermined value (N), the wireless LAN base unit is not performed without performing the processing described in step S251. The packet transmission processing by 101 ends (END). If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S247 (N), the process proceeds to step S202 in FIG. 8 to change to a low communication rate as described above. Packet retransmission processing as processing after step S203 is performed at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded (step S210), and the packet transmission process by the wireless LAN base unit 101 ends (end).

  As described above, according to the wireless LAN communication system 100 of the present embodiment, the power consumption in the wireless unit can be controlled by dynamically controlling the communication rate and transmission output without using a special packet for measuring the line quality. Can be suppressed. Thereby, the overhead of wireless communication can be eliminated.

  Further, according to the wireless LAN communication system 100 of the present embodiment, when the wireless LAN master device 101 or the wireless LAN slave device 102 that transmits a packet signal uses a secondary battery as a power source, the transmission output is dynamically controlled. Long power communication is possible due to the power saving effect.

  Furthermore, according to the wireless LAN communication system 100 of the present embodiment, it is possible to automatically control the transmission output and configure an optimal communicable area. Thereby, the influence on other radio | wireless communications can be reduced. Therefore, when the present invention is applied to 2.4 GHz band wireless LAN communication using an ISM (Industry-Science-Medical) band, a practical effect is great.

  The present invention is not limited to the embodiment described above, and various modifications can be made.

  <First Modification of Invention>

  FIG. 11 shows the configuration of the wireless LAN base unit in the wireless LAN communication system of the first modification of the present invention. In FIG. 11, the same parts as those in FIG.

In the wireless LAN master device 101A of the first modified example, a timer 301 is arranged in the threshold exceeding acknowledge counter unit 124A. The timer 301 is connected to the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126, and measures the time t ₁ from the time of activation. The timer 301 is started when the count value of the transmission output reduction threshold number counter 125 or the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124A is counted up from the initial value “0” to “1”. Done. For example, the timer 301 sets the time t ₁ to 2 seconds. If the number of transmission output reduction thresholds or the number of transmission output increase thresholds does not exceed a specified number during this period, these count values are reset to “0”. It is like that. A program for performing such control is stored in the memory 129A in the control unit 130A.

  FIG. 12 shows a main part of packet signal transmission processing of the wireless LAN base unit in the first modification. FIG. 12 corresponds to FIG. 10 in the previous embodiment. Therefore, in FIG. 12, the same step numbers as in FIG. This will be described with reference to FIGS.

  In the first modification, as in the previous embodiment, the wireless LAN base unit 101A determines the communication rate and transmission output of the packet signal for the wireless LAN handset 102 (steps S202 and S203 in FIG. 8), and the communication Will start. Assume that the wireless LAN base unit 101A transmits a packet signal with the communication rate set to a state less than the transmission output increase threshold in step S212 in FIG. In this case, control for increasing the transmission output is performed.

  After transmitting the packet signal, the wireless LAN master device 101A waits for an acknowledge response from the wireless LAN slave device 102 (step S241). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN base unit 101A notifies the acknowledge counter unit 124A that the communication with the wireless LAN handset 102 has been successful (step S242). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124A increases the transmission output increase threshold number as the count value of the transmission output increase threshold number counter 126 by “1” (step S243).

  The initial value of the count value of the transmission output increase threshold number counter 126 is “0”. Therefore, the control unit 130A checks whether or not the timer 301 is already activated when the count value of the transmission output increase threshold number counter 126 is increased by “1” (step S401). If the timer 301 is not activated (N), it is activated (step S402). Then, the current packet transmission process ends (END).

If the timer 301 has already started (step S401: Y), it is determined whether the elapsed time t ₁ from the start (step S403). When the time t ₁ has elapsed since the start (Y), the process proceeds to step S246, and the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124A are set to “ It is initialized to “0” and the current packet transmission process is terminated (END).

If the start is not elapsed time t ₁ (step S403: N), the count value of the threshold exceeds acknowledge counter unit 124A is transmitted to increased output threshold number counter 126, exceeded the predetermined specified value for advance transmission power increase threshold number It is determined whether or not it has been done (step S244). The specified value determined for the transmission output increase threshold number is, for example, 30 (times). If the count value of the transmission output increase threshold number counter 126 exceeds the specified value as a result of the success of the transmission of the packet signal (Y), the threshold excess acknowledge counter unit 124A transmits to the transmission output determination unit 123. The change of the output setting to the high output side is notified (step S245). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124A are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101A Will end (end).

  On the other hand, if the count value of the transmission output increase threshold number counter 126 after counting up in step S244 does not exceed a predetermined value (N), the wireless LAN is performed without performing the process described in step S245. The packet transmission process by the base unit 101A is finished (end). If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S241 (N), the process proceeds to step S202 in FIG. 8, and a low-speed communication rate is obtained by the process omitted in FIG. The packet retransmission processing is performed as processing after step S203 at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded and the packet transmission process by the wireless LAN base unit 101A ends (end).

  Next, processing in the first modification when the wireless LAN base device 101A transmits a packet signal in step S214 of FIG. 8 will be described. In this example, the communication rate is equal to or higher than the transmission output reduction threshold, and is a higher value that will reduce the transmission output.

  After transmitting the packet signal, the wireless LAN master device 101A waits for an acknowledge response from the wireless LAN slave device 102 (step S247). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN base unit 101A notifies the acknowledge counter unit 124A that the communication with the wireless LAN handset 102 has been successful (step S248). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124A increases the transmission output reduction threshold number as a count value of the transmission output reduction threshold number counter 125 by “1” (step S229).

  The initial value of the count value of the transmission output reduction threshold number counter 125 is “0”. Therefore, the control unit 130A checks whether the timer 301 has already been activated when the count value of the transmission output reduction threshold number counter 125 increases by “1” (step S404). If the timer 301 is not activated (N), it is activated (step S402). Then, the current packet transmission process ends (END).

If the timer 301 has already started (step S404: Y), it is determined whether the elapsed time t ₁ from the start (step S405). When the time t ₁ has elapsed since the start (Y), the process proceeds to step S246, and the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124A are set to “ It is initialized to “0” and the current packet transmission process is terminated (END).

When the time t ₁ has not elapsed since the start (step S405: N), the threshold value exceeding acknowledge counter unit 124A indicates that the count value of the transmission output reduction threshold number counter 125 exceeds a predetermined value defined for the transmission output reduction threshold number in advance. It is determined whether it has been done (step S250). The specified value determined for the number of transmission output reduction thresholds is, for example, 50 (times). If the count value of the transmission output reduction threshold number counter 125 exceeds the specified value as a result of the successful transmission of the packet signal (Y), the threshold excess acknowledge counter unit 124A transmits to the transmission output determination unit 123. The change of the output setting to the low output side is notified (step S251). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124A are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101A Will end (end).

  If the count value of the transmission output reduction threshold number counter 125 after counting up in step S250 has not exceeded a predetermined value (N), the wireless LAN base unit is not performed without performing the processing described in step S251. The packet transmission processing by 101A ends (end). If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S247 (N), the process proceeds to step S202 in FIG. 8 to change to a low communication rate as described above. Packet retransmission processing as processing after step S203 is performed at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded and the packet transmission process by the wireless LAN base unit 101A ends (end).

  In the first modified example described above, fine transmission power control that follows changes in the communication environment can be performed by control using the timer 301.

  <Second Modification of Invention>

  FIG. 13 shows the configuration of a wireless LAN base unit in the wireless LAN communication system of the second modification of the present invention. In FIG. 13, the same parts as those in FIG.

  The wireless LAN master device 101B according to the second modification includes a threshold value excess count monitoring unit 501. The threshold excess number monitoring unit 501 monitors the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124B. When both the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 exceed a predetermined communication environment determination number, for example, 20 times, the transmission output determination unit 123B sends the transmission output reduction threshold number and the transmission output. It is determined that both of the increase threshold counts have exceeded the communication environment determination count, and a change to the high output side of the transmission output setting is notified. When this notification is made, the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 initialize these count values to “0”. A program for performing such control is stored in the memory 129B in the control unit 130B.

  FIG. 14 shows a main part of packet signal transmission processing of the wireless LAN base unit in the second modification. FIG. 14 corresponds to FIG. 10 in the previous embodiment and FIG. 12 of the first modification. Therefore, in FIG. 14, the same step numbers as in FIG. This will be described with reference to FIGS.

  In the second modification, the wireless LAN base unit 101B determines the communication rate and transmission output of the packet signal to the wireless LAN handset 102 as in the previous embodiment (steps S202 and S203 in FIG. 8), and the communication Will start. It is assumed that the wireless LAN base device 101B transmits a packet signal with the communication rate set to a state below the transmission output increase threshold in step S212 in FIG. In this case, control for increasing the transmission output is performed.

  After transmitting the packet signal, the wireless LAN master device 101B waits for an acknowledge response from the wireless LAN slave device 102 (step S241). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN master device 101B notifies the acknowledge counter counter 124B that the communication with the wireless LAN slave device 102 has succeeded (step S242). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124B increases the transmission output increase threshold number as a count value of the transmission output increase threshold number counter 126 by “1” (step S243). The initial value of the count value of the transmission output increase threshold number counter 126 is “0”, and the count value is increased by “1” every time the communication success notification is received in step S242.

  The threshold value exceeding acknowledge counter unit 124B determines whether or not the count value of the transmission output increase threshold number counter 126 exceeds a predetermined value set in advance for the transmission output increase threshold number (step S244). The specified value determined for the transmission output increase threshold number is, for example, 30 (times). If the count value of the transmission output increase threshold number counter 126 exceeds a specified value as a result of the success of successful transmission of the packet signal (Y), the threshold excess acknowledge counter unit 124B transmits to the transmission output determination unit 123B. The change of the output setting to the high output side is notified (step S245). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124B are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101B Will end (end).

  On the other hand, if the count value of the transmission output increase threshold number counter 126 after counting up does not exceed a predetermined value in step S244 (N), the threshold excess number monitoring unit 501 transmits the transmission output reduction threshold number counter 125. And whether the count value of the transmission output increase threshold number counter 126 exceeds the prescribed communication environment determination number (step S601). If the communication environment determination count has not been exceeded (N), the packet transmission process by the wireless LAN base unit 101B ends without performing the process described in step S245 as in the previous embodiment (end).

  When both the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 exceed the prescribed communication environment determination number (step S601: Y), the threshold excess acknowledge counter unit 124B sends to the transmission output determination unit 123B. The change of the transmission output setting to the high output side is notified (step S245). In response to this notification, the threshold value exceeding acknowledge counter unit 124B initializes the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 to “0” (step S246). Then, the packet transmission process by the wireless LAN master device 101B is finished (end). Here, the number of communication environment judgments to be determined in step S601 is smaller than both the prescribed communication environment judgment times of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126.

  If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S241 (N), the process proceeds to step S202 in FIG. 8, and a low-speed communication rate is obtained by the process omitted in FIG. The packet retransmission processing is performed as processing after step S203 at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded, and the packet transmission process by the wireless LAN base unit 101B ends (end).

  Finally, the case where the wireless LAN base device 101B transmits a packet signal in step S214 of FIG. 8 will be described. In this example, the communication rate is equal to or higher than the transmission output reduction threshold, and is a higher value that will reduce the transmission output.

  After transmitting the packet signal, the wireless LAN master device 101B waits for an acknowledge response from the wireless LAN slave device 102 (step S247). If there is an acknowledge response within a predetermined time from the transmission of the packet signal (Y), the wireless LAN master device 101B notifies the acknowledge counter counter 124B that the communication with the wireless LAN slave device 102 has succeeded (step S248). ). Upon receipt of this notification, the threshold value exceeding acknowledge counter unit 124B increases the transmission output reduction threshold number as the count value of the transmission output reduction threshold number counter 125 by “1” (step S249). The initial value of the count value of the transmission output reduction threshold number counter 125 is “0”, and the count value is incremented by “1” each time the communication success notification in step S248 is received.

  The threshold value exceeding acknowledge counter unit 124B determines whether or not the count value of the transmission output reduction threshold number counter 125 has exceeded a predetermined value determined in advance for the transmission output reduction threshold number (step S250). The specified value determined for the number of transmission output reduction thresholds is, for example, 50 (times). If the count value of the transmission output reduction threshold number counter 125 exceeds the specified value (Y) as a result of continuous transmission of the packet signal, the threshold excess acknowledge counter unit 124B transmits to the transmission output determination unit 123B. The change of the output setting to the low output side is notified (step S251). Then, the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 in the threshold excess acknowledge counter unit 124B are initialized to “0” (step S246), and packet transmission processing by the wireless LAN base unit 101B Will end (end).

  If the count value of the transmission output reduction threshold number counter 125 after counting up in step S250 does not exceed a predetermined value (N), the threshold value excess monitoring unit 501 and the transmission output reduction threshold number counter 125 and the transmission It is checked whether the count values of the output increase threshold number counter 126 both exceed the prescribed communication environment judgment number (step S601). If the communication environment determination count has not been exceeded (N), the packet transmission process by the wireless LAN base unit 101B ends without performing the process described in step S251, as in the previous embodiment (end).

  When both the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 exceed the prescribed communication environment determination number (step S601: Y), the threshold excess acknowledge counter unit 124B sends to the transmission output determination unit 123B. The change of the transmission output setting to the high output side is notified (step S245). In response to this notification, the threshold value exceeding acknowledge counter unit 124B initializes the count values of the transmission output reduction threshold number counter 125 and the transmission output increase threshold number counter 126 to “0” (step S246). Then, the packet transmission process by the wireless LAN master device 101B is finished (end).

  If the acknowledge response from the wireless LAN slave unit 102 is not within the predetermined time in step S247 (N), the process proceeds to step S202 in FIG. 8 to change to a low-speed communication rate as described above. Packet retransmission processing as processing after step S203 is performed at the changed communication rate. When the upper limit of the packet retransmission process is exceeded (step S209: Y), the packet is discarded, and the packet transmission process by the wireless LAN base unit 101B ends (end).

  <Third Modification of the Invention>

  FIG. 15 shows a configuration of a wireless LAN base unit in a wireless LAN communication system according to a third modification of the present invention. 15, the same parts as those in FIG. 6 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

  The wireless LAN base device 101C of the third modification includes a transmission output threshold value calibration unit 701. The transmission output setting table 127C includes a good communication environment table 721 and bad communication for extracting the transmission output reduction threshold 711 and the transmission output increase threshold 712 for both cases where the communication environment is good and bad. An environment table 722 is newly stored. The memory 129C in the control unit 130C stores a program for the wireless LAN base unit 101C to change the transmission power reduction threshold and the transmission output increase threshold according to the change in the communication environment in the third modification. .

  FIG. 16 shows the main part of the calibration process of the transmission power reduction threshold and the transmission output increase threshold accompanying the change in the communication environment by the wireless LAN master of the third modification. This will be described with reference to FIGS.

  When receiving the packet signal from the wireless LAN slave device 102 shown in FIG. 5 (step S801), the wireless unit 121 of the wireless LAN master device 101C notifies the transmission output threshold value calibration unit 701 of the RSSI value (step S802). The RSSI value is the intensity of the received signal and can take a value from “0” to “255”. However, even if the same power is input to the wireless unit 121, it is known that the RSSI value varies depending on the received device. Therefore, in this embodiment, the maximum RSSI value is set to 100 percent, and a relative value expressed in percent is notified to the transmission output threshold value calibration unit 701.

  The transmission output threshold value calibration unit 701 first determines whether the notified RSSI value is 70% or more (step S803). If the RSSI value is 70% or more (Y), the transmission output threshold value calibration unit 701 determines that the wireless LAN base unit 101C is communicating with the wireless LAN handset 102 in a good communication environment. Therefore, the transmission output threshold value calibration unit 701 extracts the transmission output reduction threshold value 711 and the transmission output increase threshold value 712 using the good communication environment table 721, calibrates these threshold values (step S804), and is shown in FIG. End processing (END).

  On the other hand, when the RSSI value notified to the transmission output threshold value calibration unit 701 is less than 70 percent (step S803: N), it is determined whether this value is 30 percent or less (step S805). If it is 30% or less (Y), the transmission output threshold value calibration unit 701 determines that the wireless LAN master device 101C is communicating with the wireless LAN slave device 102 in a poor communication environment. Therefore, the transmission output threshold value calibration unit 701 extracts the transmission output reduction threshold value 711 and the transmission output increase threshold value 712 using the poor communication environment table 722, calibrates these threshold values (step S806), and is shown in FIG. End processing (END).

  Unlike the above, when the RSSI value notified to the transmission output threshold value calibration unit 701 is neither 70% nor more and 30% or less (step S803: N, step S805: N), the transmission output is performed without performing any particular calibration. Is controlled.

  FIG. 17 shows an example of a table for good communication environment, and FIG. 18 shows an example of a table for poor communication environment. In the good communication environment table 721 and the poor communication environment table 722, the transmission output increase threshold value and the transmission output decrease threshold value are set differently due to the difference in the communication environment.

  The transmission output control according to the third modification is performed independently in accordance with changes in the respective communication environments when the wireless LAN master device 101C communicates with a plurality of wireless LAN slave devices 102. As a result, it is possible to set the optimum transmission power for each wireless LAN slave device 101.

  In the embodiment and the first to third modifications described above, transmission control on the wireless LAN base units 101, 101A, 101B, 101C side has been described. The same control is possible on the wireless LAN handset 102 side. Further, the present invention can be similarly applied in a communication environment in which a plurality of wireless LAN master units share a channel by CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance).

  Further, in the transmission output setting table 127T shown in FIG. 7, the transmission output increase threshold values of “small output value” and “medium output value” and the transmission output decrease threshold values of “medium output value” and “maximum output value” are the same. Although it is a communication rate, these changes are also possible. For example, if the transmission output increase threshold value of “medium output value” is changed from 6 Mbps to 36 Mbps, the setting can be changed to the “maximum output value” transmission output earlier when the communication rate is not stable.

  When there is a communication rate to be secured at the minimum in the present invention, the initial transmission is started using the communication rate as a transmission output increase threshold, and the transmission output is sequentially decreased within a range in which the communication rate can be secured. It is also possible to make a selection. In addition, when there is a minimum communication rate to be secured in the wireless LAN communication system 100 according to the embodiment, a transmission output capable of securing the communication rate can be selected by setting the communication rate as a transmission output increase threshold. It becomes possible.

  Furthermore, in the embodiment and the first to third modifications described above, the wireless LAN is taken as an example of communication, but the present invention is not limited to this. The present invention can be similarly applied when the communication environment fluctuates even in general wireless or wired communication.

  Some or all of the embodiments described above are described as in the following supplementary notes, but are not limited to the following descriptions.

(Appendix 1)
A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions;
Prior to communication with the communication partner, communication condition initial selection means for selecting, as an initial communication condition, one combination that is likely to succeed from the communication table;
Transmitting means for transmitting a signal to the communication partner under one specified communication condition;
A response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmission means;
A communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result of the communication environment determination unit with respect to the communication condition adopted for transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit A communication condition revision means for selecting a revised communication condition to be used for transmission along the direction in which the output decreases;
Communication condition determination means for determining whether to select the next communication condition revised by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means, Transmitting device.

(Appendix 2)
In the communication table, communication conditions for a plurality of communication methods to be adapted to the communication method of the communication partner are defined, and the communication condition initial selection means and the communication condition revision means are communication adapted to the communication partner. The transmission apparatus according to appendix 1, wherein a communication condition is selected from among the methods.

(Appendix 3)
The transmission apparatus according to appendix 1, wherein a threshold value that serves as an index for the communication condition initial selection unit to select an initial communication condition is set in the communication table.

(Appendix 4)
The communication environment determining unit determines that there is a margin in the communication environment when the response receiving unit receives a response indicating success of the reception continuously for a predetermined number of times or more with respect to the signal transmission of the transmitting unit, and the communication environment The transmission apparatus according to appendix 1, wherein the condition determination means determines that the communication condition revision means can be revised to the next communication condition.

(Appendix 5)
The communication environment determining unit determines that there is a margin in the communication environment when a ratio of reception of the response indicating the success of the reception to the number of signal transmissions of the transmission unit in the same communication condition exceeds a predetermined number, The transmission apparatus according to appendix 1, wherein the condition determination means determines that the communication condition revision means can be revised to the next communication condition.

(Appendix 6)
The communication environment determination means counts when the time limit is reached before reaching the predetermined number of times, a timer for measuring a time limit for continuously receiving the response indicating the successful reception for the predetermined number of times or more The transmission apparatus according to appendix 5, further comprising count clear means for clearing the number of times.

(Appendix 7)
The transmitting apparatus according to claim 1, wherein the communication environment determining unit determines a communication environment using an RSSI (Received Signal Strength Indicator) value of a signal received by the response receiving unit.

(Appendix 8)
The transmission apparatus according to appendix 1, wherein the communication table defines a communication condition when performing communication using a wireless LAN.

(Appendix 9)
The transmission apparatus according to claim 1, wherein the communication condition revision unit revises the communication condition in a direction to decrease the communication output from the communication table and then further revise the communication condition in a direction to increase the communication rate.

(Appendix 10)
The transmission apparatus according to claim 1, wherein the communication table includes a dedicated table corresponding to each communication environment determined by the communication environment determination unit.

(Appendix 11)
A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as a communication condition, and one communication that is highly likely to succeed from the communication table prior to communication with the communication partner. Communication condition initial selection means for selecting a combination as an initial communication condition, transmission means for transmitting a signal to the communication partner under one specified communication condition, and the communication that has received the signal transmitted by the transmission means A response receiving means for receiving a response indicating successful reception from the other party, and a communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means; The determination of the communication environment determination unit with respect to the communication condition adopted for the transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit Depending on the result, the communication condition revision means for selecting the revised communication condition used for transmission along the direction in which the communication rate increases or the transmission output decreases from the communication table, and the determination result of the communication environment determination means A transmission apparatus comprising: communication condition determination means for determining whether to select the next communication condition revised by the communication condition revision means or to hold the current communication condition according to
A receiving means for receiving a signal sent from the transmitting means of the transmitting apparatus; and a receiving apparatus provided with a reply means for making a response indicating the success of the reception when the signal is successfully received by the receiving means. A communication system.

(Appendix 12)
The receiving device includes a communication method response unit that returns a communication method capable of communicating with the transmitting device, and the communication condition revision unit of the transmitting device receives the communication condition after selecting the revised communication condition from the communication table. 12. The communication system according to appendix 11, wherein one of communication methods in which the apparatus can communicate is selected.

(Appendix 13)
Among communication tables that define a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions, communication is highly likely to succeed from the communication table prior to communication with the communication partner 1 A communication condition initial selection step of selecting one combination as an initial communication condition;
A transmission step of transmitting a signal to the communication partner under one communication condition;
A response reception step for receiving a response indicating successful reception from the communication partner that has received the signal transmitted in the transmission step;
A communication environment determining step for determining a communication environment with the communication partner according to the response status received in the response receiving step;
Direction or transmission in which the communication rate increases from the communication table according to the determination result of the communication environment determination step for the communication condition adopted for transmission by the transmission step starting from the communication condition selected in the communication condition initial selection step A communication condition revision step for selecting a revised communication condition to be used for transmission along the direction in which the output decreases,
A communication condition determination step for determining whether to select the next revised communication condition or to keep the current communication condition using the communication condition revision step according to the determination result of the communication environment determination step. A characteristic communication condition determination method.

(Appendix 14)
When there is a minimum communication rate to be secured, the communication condition initial selection step selects transmission output with the communication rate as a part of the communication condition, and the communication condition revision step selects and fixes the communication rate. 14. The communication condition determination method according to appendix 13, wherein the communication condition is selected in a direction in which the transmission output decreases.

(Appendix 15)
On the computer,
Among communication tables that define a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions, communication is highly likely to succeed from the communication table prior to communication with the communication partner 1 Communication condition initial selection processing for selecting one combination as an initial communication condition;
A transmission process for transmitting a signal to the communication partner under one communication condition;
A response reception process for receiving a response indicating successful reception from the communication partner that has received the signal transmitted in the transmission process; and
A communication environment determination process for determining a communication environment with the communication partner according to the response status received by the response reception process;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result by the communication environment determination process for the communication condition adopted for transmission by the transmission process starting from the communication condition selected by the communication condition initial selection process A communication condition revision process for selecting a revised communication condition to be used for transmission along the direction in which the output decreases,
Performing a communication condition determination process for determining whether to select the next revised communication condition using the communication condition revision process or to keep the current communication condition according to the determination result of the communication environment determination process. A characteristic communication condition determination program.

(Appendix 16)
When there is a minimum communication rate to be secured, the communication condition initial selection process selects the transmission output as a part of the communication condition, and the communication condition revision process selects and fixes the communication rate. The communication condition determination program according to appendix 15, wherein the communication condition is selected in a direction in which the transmission output decreases.

10, 21 Transmitting device 11, 21a Communication table 12, 21b Communication condition initial selection means 13, 21c Transmission means 14, 21d Response receiving means 15, 21e Communication environment determination means 16, 21f Communication condition revision means 17, 21g Communication condition determination means DESCRIPTION OF SYMBOLS 20 Communication system 22 Receiving device 22a Receiving means 22b Reply means 30 Communication condition determination method 31 Communication condition initial selection step 32 Transmission step 33 Reply reception step 34 Communication environment determination step 35 Communication condition revision step 36 Communication condition determination step 40 Communication condition determination program 41 Communication condition initial selection process 42 Transmission process 43 Response reception process 44 Communication environment determination process 45 Communication condition revision process 46 Communication condition determination process 100 Wireless LAN communication system 101, 101A, 101B, 101C Wireless LAN base unit 102 wireless LAN slave device 121 wireless unit 122 communication rate determination unit 123, 123B, 123C transmission output determination unit 124, 124A, 124B, 124C threshold exceeded acknowledge counter unit 125 transmission output decrease threshold number counter 126 transmission output increase threshold number counter 127 127C Transmission output setting table section 127T Transmission output setting table 128 CPU
129, 129A, 129B, 129C Memory 130, 130A, 130B, 130C Control unit 301 Timer 501 Number monitoring unit 701 Transmission output threshold calibration unit 711 Transmission output reduction threshold 712 Transmission output increase threshold 721 Good communication environment table 722 For poor communication environment table

Claims (5)

A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions;
Prior to communication with the communication partner, communication condition initial selection means for selecting, as an initial communication condition, one combination that is likely to succeed from the communication table;
Transmitting means for transmitting a signal to the communication partner under one specified communication condition;
A response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmission means;
A communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result of the communication environment determination unit with respect to the communication condition adopted for transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit A communication condition revision means for selecting a revised communication condition to be used for transmission along the direction in which the output decreases;
Communication condition determination means for determining whether to select the next revised communication condition by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means,
In the communication table, communication conditions for a plurality of communication methods to be adapted to the communication method of the communication partner are defined, and the communication condition initial selection means and the communication condition revision means are communication adapted to the communication partner. A transmission apparatus, wherein a communication condition is selected from among methods. A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions;
Prior to communication with the communication partner, communication condition initial selection means for selecting, as an initial communication condition, one combination that is likely to succeed from the communication table;
Transmitting means for transmitting a signal to the communication partner under one specified communication condition;
A response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmission means;
A communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result of the communication environment determination unit with respect to the communication condition adopted for transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit A communication condition revision means for selecting a revised communication condition to be used for transmission along the direction in which the output decreases;
Communication condition determination means for determining whether to select the next revised communication condition by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means,
In the communication table, a threshold value is set as an index for the communication condition initial selection means to select an initial communication condition. A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions;
Prior to communication with the communication partner, communication condition initial selection means for selecting, as an initial communication condition, one combination that is likely to succeed from the communication table;
Transmitting means for transmitting a signal to the communication partner under one specified communication condition;
A response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmission means;
A communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result of the communication environment determination unit with respect to the communication condition adopted for transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit A communication condition revision means for selecting a revised communication condition to be used for transmission along the direction in which the output decreases;
Communication condition determination means for determining whether to select the next revised communication condition by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means,
The communication environment determining unit determines that there is a margin in the communication environment when the response receiving unit receives a response indicating success of the reception continuously for a predetermined number of times or more with respect to the signal transmission of the transmitting unit, and the communication environment The condition discriminating unit discriminates that the communication condition revision unit can revise the communication condition to the next communication condition. A communication table that defines a plurality of combinations of communication rates and transmission outputs when communicating with a communication partner as communication conditions;
Prior to communication with the communication partner, communication condition initial selection means for selecting, as an initial communication condition, one combination that is likely to succeed from the communication table;
Transmitting means for transmitting a signal to the communication partner under one specified communication condition;
A response receiving means for receiving a response indicating successful reception from the communication partner receiving the signal transmitted by the transmission means;
A communication environment determining means for determining a communication environment with the communication partner according to the response status received by the response receiving means;
Direction or transmission in which the communication rate increases from the communication table in accordance with the determination result of the communication environment determination unit with respect to the communication condition adopted for transmission of the transmission unit starting from the communication condition selected by the communication condition initial selection unit A communication condition revision means for selecting a revised communication condition to be used for transmission along the direction in which the output decreases;
Communication condition determination means for determining whether to select the next revised communication condition by the communication condition revision means or to keep the current communication condition according to the determination result of the communication environment determination means,
The communication environment determining unit determines that there is a margin in the communication environment when a ratio of reception of the response indicating the success of the reception to the number of signal transmissions of the transmission unit in the same communication condition exceeds a predetermined number, The condition discriminating unit discriminates that the communication condition revision unit can revise the communication condition to the next communication condition.     The communication environment determining means counts when the time limit is reached before reaching the predetermined number of times, and a timer for measuring a time limit for continuously receiving the response indicating the success of the reception for the predetermined number of times or more. 5. The transmission apparatus according to claim 4, further comprising count clear means for clearing the number of times.

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