JP5376886B2 - Wireless transmission apparatus, program, and method - Google Patents

Wireless transmission apparatus, program, and method Download PDF

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JP5376886B2
JP5376886B2 JP2008252225A JP2008252225A JP5376886B2 JP 5376886 B2 JP5376886 B2 JP 5376886B2 JP 2008252225 A JP2008252225 A JP 2008252225A JP 2008252225 A JP2008252225 A JP 2008252225A JP 5376886 B2 JP5376886 B2 JP 5376886B2
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transmission
data transmission
time
period
data
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JP2010087660A (en
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康貴 川本
潔 福井
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沖電気工業株式会社
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THIR OWN ENERGY USE
    • Y02D70/00Techniques for reducing energy consumption in wireless communication networks

Abstract

<P>PROBLEM TO BE SOLVED: To reduce throughput of data transmission in a radio transmission device setting a data transmission stop period stopping data transmission for a period not less than a shortest data transmission stop period for each period setting a longest data transmission period as a limit upon performing data transmission. <P>SOLUTION: The invention relates to a radio transmission device performing data transmission to a radio reception device. The radio transmission device has a means clocking an elapse time from the start of data transmission after the radio transmission device has started or a data transmission stop period has elapsed, a means estimating a transmission completion time from the time when the radio transmission device starts the transmission of transmission scheduled data which is going to be transmitted to the completion of the transmission, and a means performing control for prohibition of data transmission by the radio transmission device based on at least a period of data transmission under clocking and an estimated transmission completion time. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wireless transmission device, a program, and a method, and can be applied to, for example, a wireless transmission device that sets a data transmission stop period for stopping data transmission after a data transmission period for transmitting data to the wireless reception device. .

  Use of radio waves transmitted by wireless communication devices may be restricted by laws and regulations. For example, as described in Non-Patent Document 1, when wireless communication is performed in the 950 MHz band, a wireless transmission device has a data transmission period when a data transmission period continues for a predetermined time (hereinafter referred to as “data transmission longest period”). It is required to perform transmission control in which transmission is stopped and transmission is controlled to be stopped unless a predetermined time (hereinafter referred to as a “data transmission stop shortest period”) elapses.

For example, when wireless communication is performed in the 950 MHz band, the maximum data transmission period corresponding to the carrier sense time is set, and if the carrier sense time is 128 microseconds after starting data transmission for the first time, a minimum of 100 milliseconds When the carrier sense time is 10 milliseconds, data transmission must be stopped for at least 100 milliseconds after a maximum of one second.

In the conventional communication apparatus, the above-described control is realized by measuring the transmission time (radio wave transmission time) in the physical (PHY) layer. That is, it is realized by starting the timing simultaneously with the start of transmission (radio wave transmission) and stopping the transmission when the continuous transmission time has passed when a predetermined time has passed.
Information and Communications Council, "Information and Communications Council, Information and Communication Technology Subcommittee, Power Saving System Committee Report", [Online], INTERNET, [Retrieved on August 27, 2008], <http: //www.soumu.go .jp / s-news / 2007 / pdf / 071214_1_bt3.pdf>, pp. 37-41

  However, in the conventional communication apparatus, when the data to be transmitted is packet communication, if the data transmission is stopped at the same time as the remaining transmission period remaining time becomes 0, the transmission is stopped in the middle of the packet transmission. Since transmission is performed again from the beginning when transmission is possible, there is a problem that wasteful processing occurs and power is wasted.

  Therefore, when performing data transmission, in a wireless transmission device that sets a data transmission stop period for stopping data transmission for a period longer than the data transmission stop minimum period for each period with the maximum data transmission period as a limit, A wireless transmission apparatus, program, and method that can reduce the amount of processing are desired.

The wireless transmission device according to the first aspect of the present invention is (1) when performing data transmission, data transmission for a period equal to or longer than the minimum data transmission stop period for each period that is limited to the maximum data transmission period regardless of the surrounding radio wave condition. In the wireless transmission device for setting the data transmission suspension period for stopping the transmission, (2) the elapsed time from the start of data transmission after the wireless transmission device is activated or after the data transmission suspension period has elapsed (3) a transmission completion time estimating means for estimating a transmission completion time from when the wireless transmission apparatus starts transmission to completion of transmission scheduled data to be transmitted; and (4) A data transmission stop period timing means for timing the time related to the data transmission stop period; (5) at least the time measured by the data transmission period timing means; and the transmission completion time estimation Data transmission control means for performing control related to prohibition of data transmission by the wireless transmission device based on the transmission completion time estimated by the stage, and (6) the data transmission control means If it is determined that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time counted by the means is a time equal to or longer than the data transmission set time that is equal to or shorter than the data transmission longest period, the data The data transmission by the wireless transmission device is prohibited until the time measured by the transmission stop period timing means reaches the data transmission stop set time equal to or longer than the data transmission stop minimum period . (7) The data transmission control means A time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period timing means is equal to or longer than the data transmission set time. If it is determined that there is a condition in which the radio transmission apparatus performs data transmission, transmission completion time at which the transmission completion time estimating means for estimating is changed to shorter it becomes conditions applying to determine again Features.

The wireless transmission program according to the second aspect of the present invention provides: (1) When performing data transmission, data transmission is performed for a period equal to or longer than the minimum data transmission stop period for each period that is limited to the maximum data transmission period regardless of surrounding radio wave conditions. (2) From the time when the data transmission is started after the wireless transmission device is activated or after the data transmission suspension period elapses. And (3) a transmission completion time estimation means for estimating a transmission completion time from the start of transmission of the wireless transmission device to completion of transmission scheduled data to be transmitted. And (4) a data transmission stop period timing means for measuring a time related to the data transmission stop period, and (5) a time measured by at least the data transmission period timing means. And, based on the transmission completion time estimated by the transmission completion time estimation means, function as data transmission control means for performing control related to prohibition of data transmission by the wireless transmission device, (6) the data transmission control means, When it is determined that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period time measurement means is equal to or longer than the data transmission set time that is equal to or less than the data transmission longest period The wireless transmission device prohibits data transmission until the time measured by the data transmission stop period timing means reaches a data transmission stop set time equal to or longer than the minimum data transmission stop period , and (7) the data The transmission control means adds the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period timing means. If it is determined that the interval is equal to or longer than the data transmission set time, the condition for the data transmission by the wireless transmission device is changed to a condition for shortening the transmission completion time estimated by the transmission completion time estimation means. Then, it is applied to the determination again .

The wireless transmission method of the third aspect of the present invention is as follows: (1) When performing data transmission, data transmission is performed for a period equal to or longer than the minimum data transmission stop period for each period that is limited to the maximum data transmission period regardless of the surrounding radio wave condition. (2) a data transmission period timing means, a transmission completion time estimation means, a data transmission stop period timing means, and a data transmission control means, 3) The data transmission period timing unit counts the elapsed time from the start of data transmission after the wireless transmission device is activated or after the data transmission stop period has elapsed, and (4) the transmission is completed. The time estimation means estimates a transmission completion time from the start of transmission by the wireless transmission apparatus to transmission completion data to be transmitted, and (5) the data transmission The stop period timing unit counts the time related to the data transmission stop period. (6) The data transmission control unit includes at least the time measured by the data transmission period timing unit and the transmission estimated by the transmission completion time estimation unit. And (7) the data transmission control means is configured to perform the transmission completion time estimation means at a time measured by the data transmission period time measuring means, based on the completion time. If it is determined that the time obtained by adding the estimated transmission completion time is a time equal to or longer than the data transmission set time equal to or shorter than the data transmission maximum period, the time measured by the data transmission stop period time measuring means until it reaches the stop shortest period or more data transmission stop set time, to disable data transmission by the wireless transmitting device, (8) the data transmission control If it is determined that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation unit to the time measured by the data transmission period timing unit is equal to or longer than the data transmission set time, the wireless transmission The condition that the apparatus performs data transmission is changed to a condition that the transmission completion time estimated by the transmission completion time estimation means becomes shorter, and is applied to the determination again .

  When performing data transmission, the amount of processing related to data transmission in a wireless transmission device that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the minimum data transmission stop period for each period up to the maximum data transmission period Reduce.

(A) First Embodiment Hereinafter, a first embodiment of a wireless transmission device, a program, and a method according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing the overall configuration of the wireless communication system 1 of this embodiment.

  The wireless communication system 1 includes a wireless transmission device 10 and a wireless reception device 20. Since the existing communication device or the like can be applied as the wireless reception device 20, detailed description is omitted. The wireless transmission device 10 may be applied to wireless transmission in, for example, a wireless communication device in a low-power wireless system described in Non-Patent Document 1, but the wireless communication device to be applied is not limited.

  In the wireless communication system 1, radio transmission is performed by transmitting a radio wave from the wireless transmission device 10, and the wireless reception device 20 receives the data. In FIG. 1, for simplicity of explanation, the wireless reception device 20 has a single configuration, but a plurality of wireless reception devices 20 may be provided, and the number of the wireless reception devices 20 is not limited. In this embodiment, as an example, the wireless transmission device 10 is installed in a wireless communication device that performs wireless communication using the 950 MHz band in the low-power wireless system described in Non-Patent Document 1, and has a carrier sense time. Is 128 microseconds. That is, in the wireless transmission device 10, it is assumed that the maximum data transmission period is set to 100 msec and the minimum data transmission stop period is set to 100 msec. In addition, data transmission from the wireless transmission device 10 to the wireless reception device 20 is performed in units of packets. In addition, data transmission from the wireless transmission device 10 to the wireless reception device 20 is performed in units of packets.

  The wireless transmission device 10 includes a transmission time counting unit 101, a packet transmission time estimation unit 102, a control unit 103, a wireless communication unit 104, and a transmission stop time counting unit 105. The wireless transmission device 10 has a program execution configuration such as a CPU, ROM, RAM, EEPROM, and hard disk, and a device having an interface for wireless communication (not limited to one device, so that a plurality of devices can be distributedly processed). It is constructed by installing the wireless transmission program of the embodiment, etc., and can be functionally shown as in FIG. 1 described above.

  The wireless communication unit 104 has a function of transmitting radio waves to the wireless reception device 20 and transmitting data. In the wireless transmission device 10, when a data transmission request is generated, the control unit 103 determines whether transmission is possible. When it is determined that transmission is possible, the wireless communication unit 104 inserts the data into a packet and transmits the packet. To do.

  The transmission time counting unit 101 has a function of measuring the data transmission period. The transmission time counting unit 101 starts time measurement and initializes the time being measured under the control of the control unit 103. The transmission time counting unit 101 measures the elapsed time from the time when the wireless transmission device 10 is started or after transmission is started for the first time after initialization. Then, when the time measured reaches a set time that is equal to or shorter than the maximum data transmission period (hereinafter referred to as “data transmission set time”), the transmission time counting unit 101 notifies the control unit 103 to that effect.

When the wireless communication unit 104 changes from a state in which radio wave transmission is stopped to a state in which radio wave transmission is performed, it starts counting the continuous transmission time.

  The packet transmission time estimation unit 102 estimates the time (hereinafter referred to as “packet transmission completion time”) required for completing the packet transmission in which the data is inserted when a data transmission request is generated in the wireless transmission device 10. The control unit 103 is notified of the estimation result.

  The packet transmission time estimation unit 102 estimates the packet transmission completion time based on each parameter related to packet transmission in the wireless transmission device 10. The parameters used by the packet transmission time estimation unit 102 for estimating the packet transmission completion time include, for example, the length of a packet preamble (for example, a clock synchronization signal arranged at the beginning of a MAC frame), the packet header length, and the packet A combination of one or a plurality of parameters is conceivable among the payload length, carrier sense time, maximum backoff time at the time of carrier sense, and the like.

  For example, the packet transmission time estimation unit 102 may estimate the packet transmission completion time using the following equation (1).

Packet transmission completion time T1 = ((packet preamble length + packet header length + payload length) / (communication speed of wireless communication unit 104)) + (time required for carrier sense) + (maximum back-off time during carrier sense) (1)
In the wireless communication system 1 of the first embodiment, a confirmation response (hereinafter referred to as “ACK”) is notified from the wireless transmission device 10 as means for reliably transmitting data (packets) to the wireless reception device 20. And That is, when data (packet) is transmitted from the wireless transmission device 10 to the wireless reception device 20, the wireless reception device 20 notifies the wireless transmission device 10 that is the transmission source that the data (packet) has been received. Then, a confirmation (hereinafter referred to as “ACK packet”) is notified from the wireless reception device 20 to the wireless transmission device 10. When performing ACK communication, if the wireless transmission device 10 does not notify the ACK packet from the wireless reception device 20 after packet transmission, it is assumed that transmission has failed and the packet is retransmitted.

  When the ACK communication as described above is performed in the wireless communication system 1, for example, when the wireless transmission device 103 performs an acknowledgment (hereinafter referred to as “ACK”) communication in the data communication, the packet transmission time estimation is performed. In unit 102, the maximum ACK reception waiting time and ACK reception time may be further used to estimate the packet transmission completion time by the following equation (2). In addition, T1 in above-mentioned (1) Formula is applied to T1 in (2) Formula.

Packet transmission completion time T2 = T1 + (T2 + maximum ACK reception waiting time) × maximum number of retransmissions (2)
Normally, when ACK communication is performed, retransmission of packets in the case of ACK reception failure is often performed by hardware. In this case, it is often the case that software does not know that a packet has been retransmitted due to an ACK reception failure. For this reason, it is not realistic to “recalculate the packet transmission completion time each time retransmission occurs due to ACK reception failure”. When the packet transmission completion time during ACK communication takes the longest time, that is, when retransmission is performed up to the maximum number of retransmissions, it is necessary to calculate the time required for packet transmission. As the maximum number of retransmissions, the same number of times may be applied to all packets, or the number of times according to the type of data inserted in the packet or the priority information inserted in the header information of the packet. You may make it apply. Further, there may be a case where the maximum number of retransmissions is 1, that is, retransmission is not performed.

  The packet transmission completion time in the packet transmission time estimation unit 102 may be estimated using the above formulas (1) and (2), and the estimation method is not limited.

  The transmission stop time counting unit 105 has a function of measuring a period during which data transmission is stopped in the wireless transmission device 10 (hereinafter referred to as “data transmission stop period”). When the wireless transmission device 10 transitions from the data transmission state to the transmission suspension state, the transmission suspension time counting unit 105 counts the transmission suspension time from the transition timing, and further, the wireless transmission device 10 performs the data transmission state. When the transition is made, the time measurement is stopped and the time being measured is initialized. In addition, the transmission stop time timing unit 105 notifies the control unit 103 when the time being measured reaches a set time equal to or longer than the data transmission stop minimum period (hereinafter referred to as “data transmission stop set time”). To do. Also, the transmission stop time counting unit 105 may start the time measurement when the transmission time counting unit 101 reaches the data transmission set time, or a control unit described later. In 103, when the result of determining whether or not transmission of the data transmission requested to be transmitted is not possible, the timing of the time may be started, and the timing at which the data transmission stop period can be counted is acceptable. For example, the timing to start timing is not limited.

  When a request for data transmission occurs in the wireless transmission device 10, the control unit 103 determines whether the data transmission is possible. If the determination result is transmittable, the control unit 103 permits the wireless communication unit 104 to transmit the data, If the determination result is not transmittable, the data transmission request is rejected.

  When a request for data transmission occurs in the wireless transmission device 10, the control unit 103 causes the packet transmission time estimation unit 102 to estimate the packet transmission completion time when the data is transmitted. Refer to the time being measured. Then, based on at least the time measured by the transmission time counting unit 101 and the packet transmission completion time estimated by the packet transmission time estimation unit 102, it is determined whether or not transmission of data transmission requested for transmission is possible. For example, when the time obtained by adding the packet transmission completion time to the time measured by the transmission time measuring unit 101 exceeds the data transmission setting time, it is determined that data transmission is possible, and the time is equal to or less than the data transmission setting time. Alternatively, it may be determined that data transmission is impossible.

  If the result of determining whether or not the transmission of the data transmission requested to be transmitted is not possible, the control unit 103 then sets the time measured from the transmission stop time counting unit 105 to the data transmission stop set time. The transmission time timer 101 and the transmission stop time timer 105 are initialized after prohibiting data transmission by the wireless communication unit 104 until the notification of the arrival is received. In addition, when the result of determining whether or not the transmission of the data transmission requested to be transmitted is not possible, the control unit 103 sets the data transmission stop setting from the transmission stop time measuring unit 105 thereafter. Transmission may be permitted and transmitted at a timing after receiving notification that the time has been reached.

  In addition, when the control unit 103 receives a notification that the time counted from the transmission time counting unit 101 has reached the data transmission set time, the control unit 103 subsequently counts the time from the transmission stop time counting unit 105. The transmission time timer 101 and the transmission stop time timer 105 are initialized after prohibiting data transmission by the wireless communication unit 104 until the notification that the time has reached the data transmission stop set time is received. Also good. In addition, when the transmission time counting unit 101 is measuring the time, the control unit 103 receives a notification from the transmission stop time counting unit 105 that the measured time has reached the data transmission stop set time. The transmission time measuring unit 101 and the transmission stop time measuring unit 105 may be initialized, and the time measurement by the transmission time measuring unit 101 may be resumed.

(A-2) Operation of the First Embodiment Next, the operation of the wireless transmission device 10 of the first embodiment having the above configuration will be described.

  FIG. 2 is a flowchart illustrating an operation when a data transmission request is generated in the wireless transmission device 10.

  When a data transmission request is generated in the wireless transmission device 10 (S101), the control unit 103 controls the packet transmission time estimation unit 102, and the packet transmission completion time of the data (packet) requested to be transmitted in step S101. It is estimated (S102). Then, the control unit 103 refers to the time measured by the transmission time counting unit 101 (S103).

  Next, based on the packet transmission completion time estimated in the above-described step S101 and the time acquired in the above-described step S102, the control unit 103 determines whether or not to transmit the data requested to be transmitted in the above-described step S101. When the determination result indicates that transmission is possible, the operation starts from step S105, which will be described later. When the determination result cannot be transmitted, operation starts from step S106, which will be described later (S104).

  If it is determined in step S104 that data transmission is possible, the packet in which the data requested to be transmitted is inserted in step S101 is transmitted (S105), and then the wireless transmission device 10 transmits the data. If there is a request, the operation starts again from step S101 described above.

  If it is determined in step S105 that data transmission is impossible, the data requested to be transmitted in step S101 is rejected without being transmitted (S106), and then the wireless transmission device 10 performs data transmission. When there is a request, the operation starts again from step S101 described above.

  Next, an example of data transmission operation by the wireless transmission device 10 will be described.

  FIG. 3 is a timing chart illustrating an example of data transmission operation by the wireless transmission device 10.

  In FIG. 3, it is assumed that the wireless transmitter 10 is activated at time t11 and the time measured by the transmission time timer 101 and the transmission stop time timer 105 are both in the initial state (0). Further, in FIG. 3, description will be made assuming that the data transmission set time is 100 msec and the data transmission stop set time is 100 msec.

  First, it is assumed that data (packet) is continuously transmitted in the wireless transmission device 10 for 70 msec from time t11 to time t12.

  At time t12, a new data transmission request is generated in the wireless transmission device 10, and the packet transmission completion time of the packet into which the data is inserted is estimated to be 20 msec by the packet transmission time estimation unit 102. . At time t12, the time measured by the transmission time counting unit 101 is 70 msec, and even if 20 msec is added, the time is 90 msec, which is less than the data transmission set time. It is determined that transmission is possible and transmitted.

  At time t13, a new data transmission request is generated in the wireless transmission device 10, and the packet transmission completion time of the packet into which the data is inserted is estimated to be 15 msec by the packet transmission time estimation unit 102. . At time t13, the time measured by the transmission time counting unit 101 is 90 msec, and adding 15 msec exceeds the data transmission setting time. Therefore, the control unit 103 cannot transmit the data requested to be transmitted. A decision is made and the data transmission is rejected. At time t <b> 13, data transmission in the wireless transmission device 10 is rejected, data transmission is prohibited thereafter, and transmission stop time counting unit 105 starts measuring the transmission stop time.

  Then, at time t14 after 100 msec from t13, since the transmission stop time counting unit 105 reaches the data transmission stop set time, the data transmission prohibition in the wireless transmission device 10 is canceled, and the data rejected at the above-described time t13 Transmission retransmission can be started.

(A-3) Effect of First Embodiment In the wireless transmission device 10, a transmission request is made using the time measured by the transmission time counting unit 101 and the packet transmission completion time estimated by the packet transmission time estimation unit 102. It is determined whether or not to send the data immediately. Thereby, for example, the data transmission period reaches the longest data transmission period during data (packet) transmission, and extra data (packet) transmission such as retransmission after the data transmission stop period is not performed. Effects such as reduction and power saving can be achieved.

(B) Second Embodiment Hereinafter, a second embodiment of the wireless transmission device, program and method according to the present invention will be described in detail with reference to the drawings.

(B-1) Configuration of Second Embodiment FIG. 4 is a block diagram showing an overall configuration of a wireless communication system 1A of this embodiment.

  In the second embodiment, in the wireless transmission device, when the remaining transmittable period is short, the condition related to data (packet) transmission by the wireless communication unit is changed to shorten the time required for packet transmission, and packet transmission is performed again. This is different from the first embodiment in that the time required for the transmission is estimated and compared with the remaining transmission time.

  Hereinafter, the difference between the second embodiment and the first embodiment will be described.

  The wireless communication system 1A includes a wireless transmission device 10A and a wireless reception device 20. Since the wireless reception device 20 is the same as that of the first embodiment, detailed description thereof is omitted.

  The wireless transmission device 10A includes a transmission time counting unit 101, a packet transmission time estimation unit 102, a control unit 103A, and a wireless communication unit 104.

  Since the transmission time counting unit 101 and the packet transmission time estimation unit 102 are the same as those in the first embodiment, detailed description thereof will be omitted.

  When the time obtained by adding the packet transmission completion time to the time measured by the transmission time counting unit 101 exceeds the data transmission setting time, the control unit 103A estimates the setting of the wireless communication unit 104. The packet transmission completion time is changed so that the packet transmission completion time is shortened, and the packet transmission completion time is re-estimated by the packet transmission time estimation unit 102 and applied again to the determination of whether or not packet transmission is possible. This is different from the part 103.

  The means for changing the estimated packet transmission completion time to be shortened may be realized by, for example, shortening the packet size or reducing the number of retransmissions, or combining a plurality of the above-described means And so on.

  Specifically, the preamble length is shortened, the maximum number of retransmissions when ACK reception fails is reduced, or the contents of the packet header are shortened. For example, in IEEE 802.15.4, communication is possible using two types of addresses, a 16-bit address and a 64-bit address. In order to shorten the packet header, data communication may be performed using a 16-bit address.

(B-2) Operation of Second Embodiment FIG. 5 is a flowchart illustrating an operation when a data transmission request is generated in the wireless transmission device 10A.

  When a data transmission request is generated in the wireless transmission device 10A (S201), the control unit 103A controls the packet transmission time estimation unit 102, and in step S201, the packet transmission completion time related to the data requested for transmission is estimated. (S202). Then, the control unit 103A refers to the time measured by the transmission time counting unit 101 (S203).

  Next, based on the packet transmission completion time estimated in step S201 described above and the time acquired in step S202 described above, the control unit 103A determines whether or not to transmit data requested for transmission in step S201 described above. When the determination result indicates that transmission is possible, the operation starts from step S205, which will be described later. When the determination result cannot be transmitted, operation starts from step S206, which will be described later (S204).

  If it is determined in step S204 that data transmission is possible, the packet in which the data requested to be transmitted is inserted in step S201 is transmitted (S205), and then the wireless transmission device 10A transmits the data. If there is a request, the operation starts again from step S201 described above.

  If it is determined in step S205 that data transmission is impossible, the control unit 103A controls the wireless communication unit 104 to shorten the packet transmission completion time, and starts again from step S202. (S206).

  Note that in step S206 described above, even if the control unit 103A executes control for shortening the estimated packet transmission completion time for the wireless communication unit 104 a predetermined number of times (or one or more times), If it is not determined that transmission is possible, the control for shortening the packet transmission completion time is stopped, the packet of the data requested to be transmitted in step S201 is rejected without being transmitted, and the period data of the data transmission stop set time You may make it operate | move from the above-mentioned step S201 after prohibiting transmission.

  Next, an example of data transmission operation by the wireless transmission device 10A will be described.

  FIG. 6 is a timing chart illustrating an example of data transmission operation by the wireless transmission device 10A.

  In FIG. 6, description will be made assuming that the wireless transmitter 10 </ b> A is activated at time t <b> 21 and the time measured by the transmission time measuring unit 101 and the transmission stop time measuring unit 105 are both in the initial state (0). In FIG. 6, description will be made assuming that the data transmission set time is 100 msec and the data transmission stop set time is 100 msec.

  First, it is assumed that data (packet) is continuously transmitted in the wireless transmission device 10A during 70 msec from time t21 to time t22.

  Then, at time t22, a new data transmission request is generated in the wireless transmission device 10A, and the packet transmission time estimation unit 102 estimates that the packet transmission completion time of the packet into which the data is inserted is 20 msec. . At time t22, the time measured by the transmission time counting unit 101 is 70 msec, and even if 20 msec is added, it is 90 msec, which is equal to or less than the data transmission setting time. It is determined that transmission is possible and transmitted.

  At time t23, a new data transmission request is generated in the wireless transmission device 10A, and the packet transmission time estimation unit 102 estimates that the packet transmission completion time of the packet into which the data is inserted is 15 msec. . At time t23, the time measured by the transmission time measuring unit 101 is 90 msec, and adding 15 msec exceeds the data transmission setting time, so that the control unit 103A cannot transmit the data requested to be transmitted. Once determined. Then, the control unit 103A controls the wireless communication unit 104 to shorten the packet transmission completion time by the process of step S206 described above, and as a result, the packet transmission time estimation unit under new conditions. Assume that the packet transmission completion time of the packet into which the data is inserted is estimated to be 9 msec. At time t23, the time measured by the transmission time counting unit 101 is 90 msec, and even if 9 msec is added, it is 99 msec, which is equal to or less than the data transmission setting time. It is determined that data can be transmitted and transmitted.

  Thereafter, the time measured by the transmission time counting unit 101 at time t24 becomes the data transmission setting time, and data transmission is prohibited in the wireless transmission device 10 for 100 msec from time t24 to t25.

(B-3) Effect of Second Embodiment The control unit 103A determines that the time obtained by adding the packet transmission completion time to the time measured by the transmission time measuring unit 101 exceeds the data transmission set time. Since the setting of the wireless communication unit 104 is changed so that the estimated packet transmission completion time is shortened, the frequency of rejecting the data transmission request is reduced compared to the first embodiment, More efficient data transmission can be performed.

(C) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(C-1) In the second embodiment, the control unit 103A uses the preamble for data (packet) transmission as means for changing the setting of the wireless communication unit 104 so as to shorten the estimated packet transmission completion time. The length may be set short. For example, when the antenna of the wireless communication unit 104 employs antenna diversity, the preamble length may be automatically set to be long. In this case, the preamble length can be set shorter by disabling the antenna diversity function.

(C-2) In each of the above embodiments, the packet transmission completion time is estimated by the packet transmission time estimation unit every time a data transmission request is made. The time may be set in the control unit as the packet transmission completion time of all data, and the packet transmission time estimation unit may be omitted. As a result, the wireless transmission apparatus does not have to perform the process of estimating the packet transmission completion time each time a data transmission request is made, so that the amount of processing related to data transmission can be reduced.

  Further, in each of the above embodiments, in the estimation of the packet transmission completion time by the packet transmission time estimation unit, when applying the above equation (2), the maximum number of transmissions is applied as the same number of times for all packets, The packet transmission completion time estimation for each packet to be transmitted may be omitted.

(C-3) In each of the above embodiments, when the wireless transmission device 10 transitions from the data transmission state to the transmission suspension state, the transmission suspension time counting unit 105 counts the transmission suspension time from the transition timing. However, for example, a data transmission period and a period during which data transmission is prohibited (that is, a data transmission stop period) may be repeated alternately at the same interval. For example, it is possible to repeat the provision of a 100 msec data transmission period and then a period of prohibiting 100 msec data transmission. In this case, for example, the transmission time measuring unit 101 and the transmission stop time measuring unit 105 alternately measure the time, and at least the data transmission stop time measuring unit 105 measures the time, the data in the wireless transmission device 10 Transmission may be prohibited.

It is the block diagram shown about the whole structure of the radio | wireless communications system which concerns on 1st Embodiment. 5 is a flowchart illustrating data transmission in the wireless transmission device according to the first embodiment. 6 is a timing chart illustrating an example of an operation when a data transmission request is made in the wireless transmission device according to the first embodiment. It is the block diagram shown about the whole structure of the radio | wireless communications system which concerns on 2nd Embodiment. 6 is a timing chart illustrating an example of an operation when there is a data transmission request in the wireless transmission device according to the second embodiment. 10 is a timing chart illustrating an example of data transmission operation in the wireless transmission device according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Radio transmission apparatus, 101 ... Transmission time measuring part, 102 ... Packet transmission time estimation part, 103 ... Control part, 104 ... Wireless communication part, 105 ... Transmission stop time measuring part, 20 ... Wireless reception apparatus.

Claims (9)

  1. In a wireless transmission device that sets a data transmission stop period for stopping data transmission for a period longer than the minimum data transmission stop period for each period that limits the maximum data transmission period regardless of the surrounding radio wave condition when performing data transmission ,
    A data transmission period timing means for counting the elapsed time from the time when the data transmission is started after the wireless transmission device is activated or after the data transmission stop period has elapsed;
    Transmission completion time estimating means for estimating a transmission completion time from the start of transmission of the wireless transmission device to completion of transmission scheduled data to be transmitted;
    A data transmission suspension period timing means for timing the time associated with the data transmission suspension period;
    Data transmission control means for performing control related to prohibition of data transmission by the wireless transmission device based on at least the time measured by the data transmission period time measuring means and the transmission completion time estimated by the transmission completion time estimation means Have
    The data transmission control means is configured such that a time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to a time measured by the data transmission period timing means is equal to or longer than a data transmission set time equal to or shorter than the data transmission longest period. If it is determined that it is time, data transmission by the wireless transmission device is prohibited until the time measured by the data transmission stop period timing means reaches a data transmission stop set time that is equal to or longer than the minimum data transmission stop period. And
    When the data transmission control means determines that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period timing means is equal to or longer than the data transmission set time. The wireless transmission device is characterized in that the condition for performing data transmission by the wireless transmission device is changed to a condition in which the transmission completion time estimated by the transmission completion time estimation means becomes shorter, and is applied to the determination again .
  2. If the data related to the confirmation response cannot be received from the other wireless transmission device after transmitting the data to the other wireless transmission device, a retransmission means for retransmitting the data to the other wireless transmission device up to the maximum number of retransmissions Further comprising
    The radio transmission apparatus according to claim 1 , wherein the transmission completion time estimation means estimates a time until the transmission-scheduled data is retransmitted for the maximum number of retransmissions as a transmission completion time.
  3. When the data transmission control means changes the condition for the data transmission by the radio transmission apparatus to a condition for shortening the transmission completion time estimated by the transmission completion time estimation means, at least the radio transmission apparatus performs data transmission. The radio transmission apparatus according to claim 1 or 2 , wherein the preamble length at the time of transmission is changed to be shorter.
  4. The transmission completion time estimation unit applies, as an estimation result, a transmission completion time related to data of a maximum size that can be transmitted by the wireless transmission device for all transmission scheduled data. 4. The wireless transmission device according to any one of 3 .
  5. The data transmission maximum period, the data transmission stop shortest period, and the data transmission stop period, claims 1-4, characterized in that the radio communication in a predetermined frequency band, those defined by law The wireless communication device according to any one of the above.
  6. The wireless communication apparatus according to claim 5 , wherein the predetermined frequency band is a 920 MHz to 950 MHz band.
  7. After the wireless communication device completes data transmission, it confirms that data transmission by the wireless communication device has been completed normally by receiving a confirmation response to the effect that data reception has been completed from the wireless communication device that is the data transmission destination. the wireless communication apparatus according to any one of claims 1 to 6, further comprising a response confirmation unit configured to.
  8. When transmitting data, a wireless transmission device that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the minimum data transmission stop period for each period up to the maximum data transmission period regardless of surrounding radio wave conditions Install the computer
    A data transmission period timing means for counting the elapsed time from the time when the data transmission is started after the wireless transmission device is activated or after the data transmission stop period has elapsed;
    Transmission completion time estimating means for estimating a transmission completion time from the start of transmission of the wireless transmission device to completion of transmission scheduled data to be transmitted;
    A data transmission suspension period timing means for timing the time associated with the data transmission suspension period;
    Function as data transmission control means for performing control related to prohibition of data transmission by the wireless transmission device based on at least the time measured by the data transmission period time measuring means and the transmission completion time estimated by the transmission completion time estimation means Let
    The data transmission control means is configured such that a time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to a time measured by the data transmission period timing means is equal to or longer than a data transmission set time equal to or shorter than the data transmission longest period. If it is determined that it is time, data transmission by the wireless transmission device is prohibited until the time measured by the data transmission stop period timing means reaches a data transmission stop set time that is equal to or longer than the minimum data transmission stop period. And
    When the data transmission control means determines that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period timing means is equal to or longer than the data transmission set time. A wireless transmission program , wherein the wireless transmission device changes data transmission conditions to a condition that the transmission completion time estimated by the transmission completion time estimation means becomes shorter, and is applied to the determination again .
  9. In a wireless transmission device that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the minimum data transmission stop period for each period that limits the maximum data transmission period regardless of surrounding radio wave conditions when performing data transmission In the wireless transmission method,
    Data transmission period timing means, transmission completion time estimation means, data transmission stop period timing means, data transmission control means,
    The data transmission period timing means counts the elapsed time from the start of data transmission after the wireless transmission device is activated or after the data transmission stop period has elapsed,
    The transmission completion time estimation means estimates the transmission completion time from the start of transmission of the wireless transmission device to transmission completion data to be transmitted,
    The data transmission stop period timing means measures the time related to the data transmission stop period,
    The data transmission control means performs control related to prohibition of data transmission by the wireless transmission device based on at least the time measured by the data transmission period time measuring means and the transmission completion time estimated by the transmission completion time estimation means. Do,
    The data transmission control means is configured such that a time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to a time measured by the data transmission period timing means is equal to or longer than a data transmission set time equal to or shorter than the data transmission longest period. If it is determined that it is time, data transmission by the wireless transmission device is prohibited until the time measured by the data transmission stop period timing means reaches a data transmission stop set time that is equal to or longer than the minimum data transmission stop period. And
    When the data transmission control means determines that the time obtained by adding the transmission completion time estimated by the transmission completion time estimation means to the time measured by the data transmission period timing means is equal to or longer than the data transmission set time. A wireless transmission method characterized in that the condition for performing data transmission by the wireless transmission device is changed to a condition in which the transmission completion time estimated by the transmission completion time estimation means becomes shorter, and is applied to the determination again .
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