JP2011049771A - Radio communication device and program, and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve communication efficiency in a communication system having limitation related to the continuous data transmission of each radio communication device. <P>SOLUTION: The radio communication system has a plurality of the radio communication devices each setting a data transmission stop period for stopping data transmission for a period of the shortest data transmission stop period or longer in each period in which the longest data transmission period is limited when continuously performing data transmission to the other radio communication device. Each radio communication device includes: a means for holding a start time related to a data transmission stop period at least in the radio communication device of a transmission source in the case of receiving transfer data needed to be transferred to the radio communication device of a transfer destination from the radio communication device of the transmission source; and a means for storing the transfer data needed to be transferred to the radio communication device of the transfer destination and starting data transmission to the radio communication device of the transfer destination after starting an estimated data transmission stop period of the radio communication device of the transmission source. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless communication device, a program, and a wireless communication system, and can be applied to, for example, a wireless communication system that performs multi-hop communication.

  In a wireless communication system in which a plurality of wireless communication apparatuses share the same channel (frequency) and perform multi-hop communication, CSMA / CA is a method for avoiding contention when a plurality of wireless communication apparatuses access the same channel. (Carrier Sense Multiple Access / Collision Avoidance) method. In communication between wireless communication apparatuses adopting the CSMA / CA method, collision (collision of signals flowing through the same channel) cannot be detected directly. Make sure that the data is sent.

  In addition, in a communication system that performs similar multi-hop communication, it is known that intermittent transmission of data rather than continuous transmission of data has higher throughput (see Patent Document 1, FIG. 13, etc.). ). This is because if the data is continuously transmitted, the adjacent wireless communication device detects the carrier and cannot perform data transmission. Even when CSMA / CA is not used, if data is transmitted continuously, collision occurs during data transfer and data cannot be received correctly.

  Next, an example of a technique for avoiding collision in a conventional wireless communication system that performs multi-hop communication in a plurality of wireless communication devices will be described with reference to the drawings (FIGS. 7 to 10).

  FIG. 7 is an explanatory diagram illustrating a configuration example of a conventional communication system. As illustrated in FIG. 7, the conventional communication system 300 is described as including three wireless communication devices 301 to 303. . In the communication system 300, data is transmitted from the wireless communication device 301 to the wireless communication device 303 via the wireless communication device 302 by multi-hop communication.

  FIG. 8 is an explanatory diagram showing communication timings of the wireless communication apparatuses 301 to 303 in the communication system 300.

  As shown in FIG. 8, data (data T) transmitted from the wireless communication device 301 at an arbitrary time T is first received by the wireless communication device 302 (S 401), and then transmitted from the wireless communication device 302 to the wireless communication device 303. (S402).

  FIG. 9 is an explanatory diagram illustrating communication timing when continuous data transmission is performed between wireless communication devices in the communication system 300. FIG. 10 is a diagram illustrating intermittent data transmission between wireless communication devices in the communication system 300. It is explanatory drawing shown about the communication timing in the case of transmitting.

  As shown in FIG. 9, in the communication system 300, when continuous data transmission is performed between wireless communication devices, the wireless communication device 301 continuously transmits data T to the wireless communication device 302 immediately after transmitting data T at time T. (S501). In that case, when the wireless communication apparatus 302 transfers the data T to the wireless communication apparatus 303, the wireless communication apparatus 301 transmits another data to the wireless communication apparatus 302, so that a collision occurs and the data T is transferred. (S502), and there is a problem that the throughput is reduced.

  In order to solve the problem as shown in FIG. 9, there has conventionally been a method of intermittently transmitting data between wireless communication apparatuses as shown in FIG. 10.

  As shown in FIG. 10, when the wireless communication device 301 transmits data T to the node 302 (S601), the data T is further transferred from the wireless communication device 302 to the wireless communication device 303 (S602).

  When the wireless communication device 301 transmits the next data to the wireless communication device 302 after completing the data transmission in step S601, the wireless communication device 301 is sufficient to complete the data transmission in step S602 described above by the node 302. After waiting for time (transmission standby time), data transmission is resumed (S603).

  As shown in FIG. 10, when the wireless communication device 301 intermittently transmits data, the above-described collision or the like as shown in FIG. 9 does not occur, and multihop communication between the wireless communication devices can be performed smoothly. Can do.

JP 2006-319787 A

  However, in the conventional wireless communication system, even when data is transmitted intermittently between the wireless communication devices (wireless communication devices) as shown in FIG. There are problems as described below.

  For example, in Japan, 950 MHz band wireless communication requires that data transmission be prohibited for at least 100 milliseconds (legal transmission prohibition period) after 100 milliseconds (legal continuous transmission possible period) have elapsed since the start of transmission. However, if transmission is stopped within 100 milliseconds (legal continuous transmission possible period) after transmission is started, data transmission can be resumed if data transmission is suspended for 100 milliseconds (legal transmission prohibited period) from that time. "

  FIG. 11 is an explanatory diagram showing restrictions on continuous data transmission in 950 MHz band wireless communication.

  As shown in FIG. 11, in a wireless communication device that uses a frequency of 950 MHz for wireless communication, when data transmission is continuously performed to another wireless communication device, a data transmission period is started after data transmission is started ( The longest period of (continuous transmission period) must be (statutory) continuous transmission possible period, and after the data transmission is stopped, the minimum period of data transmission stop (transmission stop period) is (legal) transmission It is illegal if it is not prohibited.

  FIG. 12 shows communication timing when data is intermittently transmitted between wireless communication devices (see FIG. 10) in the conventional communication system 300 described above (see FIG. 11) and there is a restriction on the continuous communication possible time (see FIG. 11). It is explanatory drawing shown about.

  In the communication system 300, when there is a restriction related to continuous data transmission, as shown in FIG. 12, after the wireless communication device 301 transmits data T to the wireless communication device 302 (S701), after the transmission standby time, the next data It is assumed that transmission is to be performed (S702).

  At this time, for example, if the transmission standby time of the wireless communication device 301 is equal to or longer than the legally continuous transmittable period, the next attempt to transmit data to the wireless communication device 302 in step S702 will enter the legal transmission prohibition period. Transmission cannot be performed, and it is necessary to wait further until the legal transmission prohibition period elapses.

  As shown in FIG. 12, in the wireless communication apparatus 301, the next data transmission cannot be performed until both the transmission standby time and the legal transmission prohibition period elapse, and the throughput is reduced.

  Therefore, there is a demand for a wireless communication device and program capable of improving communication efficiency and a wireless communication system in a communication system with restrictions on continuous data transmission of each wireless communication device.

  In the first aspect of the present invention, when data is continuously transmitted to another wireless communication device, data transmission is performed such that data transmission is stopped 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. In the wireless communication device that sets the stop period, (1) when transfer data that needs to be transferred to the transfer destination wireless communication device is received from the transmission source wireless communication device, at least in the transmission source wireless communication device. Data transmission stop period holding means for holding the start time of the data transmission stop period; and (2) when transfer data that needs to be transferred to the transfer destination wireless communication apparatus is received from the transmission source wireless communication apparatus, The transfer data is accumulated, and after the data transmission stop period held by the data transmission stop period holding means starts, the transmission of the accumulated transfer data to the transfer destination wireless communication device is started. And having a data transfer means for starting a.

  The wireless communication program of the second aspect of the present invention is (1) when continuously transmitting data to other wireless communication devices, for each period that is limited to the maximum data transmission period, When a computer mounted in a wireless communication device that sets a data transmission suspension period for stopping data transmission is received from the transmission source wireless communication device (2) transfer data that needs to be transferred to the wireless communication device of the transfer destination And at least data transmission stop period holding means for holding a start time of a data transmission stop period in the transmission source wireless communication apparatus, and (3) transfer data that needs to be transferred to the transfer destination wireless communication apparatus, When the data is received from the wireless communication apparatus as the transmission source, the transfer data is accumulated, and after the data transmission stop period held by the data transmission stop period holding means starts, the transfer is started. To previous wireless communication device, characterized in that to function as a data transfer means for initiating transmission of the accumulated transferred data.

  According to a third aspect of the present invention, in a wireless communication system including a plurality of wireless communication devices, the wireless communication device of the first aspect of the present invention is applied as each of the wireless communication devices.

  ADVANTAGE OF THE INVENTION According to this invention, communication efficiency can be improved in the communication system with the restriction | limiting which concerns on the continuous data transmission of each radio | wireless communication apparatus.

It is the block diagram shown about the functional structure of the radio | wireless communication apparatus which concerns on 1st Embodiment. It is explanatory drawing shown about the whole structure of the radio | wireless communications system which concerns on 1st Embodiment. In the radio | wireless communications system which concerns on 1st Embodiment, it is explanatory drawing shown about the example of the communication timing of each radio | wireless communication apparatus. In the radio | wireless communications system which concerns on 1st Embodiment, it is explanatory drawing shown about the example of the communication timing of each radio | wireless communication apparatus in case data transfer is repeated in multiple times. It is explanatory drawing shown about the whole structure of the radio | wireless communications system which concerns on 2nd Embodiment. In the radio | wireless communications system which concerns on 2nd Embodiment, it is explanatory drawing shown about the example of the communication timing of each radio | wireless communication apparatus. It is explanatory drawing shown about the whole structure of the conventional radio | wireless communications system. It is explanatory drawing shown about the example of the communication timing of the radio | wireless communication apparatus in the conventional radio | wireless communications system. It is explanatory drawing shown about the communication timing at the time of performing continuous data transmission between radio | wireless communication apparatuses in the conventional radio | wireless communications system. It is explanatory drawing shown about the communication timing in the case of performing data transmission intermittently between radio | wireless communication apparatuses in the conventional radio | wireless communications system. It is explanatory drawing shown about the restrictions which concern on the continuous data transmission in the radio | wireless communication of 950 MHz band. In the conventional communication system, it is explanatory drawing shown about the example of the communication timing when there exists a restriction | limiting in continuous communication possible time.

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

(A-1) Configuration of the First Embodiment FIG. 2 is a block diagram showing the overall configuration of the wireless communication system 10 of the first embodiment. In FIG. 2, the reference numerals in parentheses are used only in the second embodiment described later.

  In the wireless communication system 10, three wireless communication devices 20 (20-1 to 20-3) are arranged. Note that the number of wireless communication devices 20 arranged in the wireless communication system 10 is not limited.

  In the first embodiment, the wireless communication devices 20-1 to 20-3 are described as being capable of multihop communication, but communication other than multihop communication (for example, two wireless communication devices simply communicate directly). Case). When performing multi-hop communication between the wireless communication devices 20-1 to 20-3, for example, data transmitted from the wireless communication device 20-1 to the wireless communication device 20-3 is transmitted to the wireless communication device 20-. 2 will be described as reaching the wireless communication apparatus 20-3.

  In the first embodiment, as an example, each wireless communication device 20 performs data transmission in frame units (packet units) and continuously transmits a plurality of frames (packets) is called continuous data transmission. Will be described.

  Further, in the wireless communication system 10, it is assumed that each wireless communication device 20 has restrictions related to continuous data transmission. As specific contents of the restrictions related to continuous data transmission in the wireless communication system 10, it is assumed that a continuous transmission enable period and a transmission prohibition period as shown in FIG. 11 are set. In addition, the continuous transmission possible period and the transmission prohibition period applied in the wireless communication system 10 are not limited to those statutory. In other words, the wireless communication system 10 may apply an arbitrarily determined length to the continuous transmission enable period and the transmission prohibition period.

  FIG. 1 is a block diagram illustrating a functional configuration inside the wireless communication device 20.

  The wireless communication device 20 includes a transmission unit 201, a reception unit 202, a transmission source transmission stop period estimation unit 203, and a control unit 204.

  Here, for example, the wireless communication apparatus 20 performs communication processing, data processing (data transmission / reception processing, transfer processing, etc.), etc., in addition to a hardware communication unit (transmission unit 201, reception unit 202, etc.). CPU, ROM, RAM, and the like, and a program (including the wireless communication program of the embodiment) executed by the CPU is installed. FIG. 1 shows a functional configuration of the wireless communication apparatus 20 including the above-described program.

  The transmission unit 201 and the reception unit 202 are communication interfaces for performing wireless communication with other wireless communication devices 20 in the wireless communication device 20, and the communication method is not limited, but a wireless LAN (for example, IEEE 802. 11 series, etc.), ZigBee, wireless tags and the like in existing wireless communication devices such as wireless tags can be applied. Further, the frequency band used by each wireless communication device 20 in the wireless communication system 10 for wireless communication is not limited to the communication band such as the 950 MHz band, and an arbitrary band may be used.

  The receiving unit 202 also provides the data received from other communication devices to the transmission source transmission stop period estimating unit 203.

  The transmission source transmission stop period estimation unit 203 receives data (hereinafter referred to as “transfer data”) that needs to be transferred from the reception unit 202 to another wireless communication device 20, and transmits the direct transmission source of the transfer data. In the communication apparatus, the next estimated time when the transmission prohibition period starts (hereinafter referred to as “transmission prohibition start estimated time”) and the length of the transmission prohibition period (hereinafter referred to as “transmission suspension period length”) are estimated. (Or hold), and notifies the control unit 204 of the estimation result (or held content). The transmission source transmission stop period estimation unit 203 may omit the transmission stop period length estimation process and estimate only the transmission stop period start time.

  In this embodiment, in the communication system 10, the transmission suspension period of each wireless communication device 20 is described as a period that coincides with the transmission prohibited period. However, a period longer than the transmission prohibited period is applied. Also good. In the first embodiment, it is desirable in terms of communication efficiency that the transmission suspension period of each wireless communication device 20 is the same as the transmission prohibition period.

  As a method of estimating the transmission stop period start time and the transmission stop period length in the transmission source transmission stop period estimation unit 203, there are the following three methods, for example.

(Estimation Method 1) A time at which continuous data transmission is terminated from the communication device that is the transmission data transmission source (hereinafter referred to as “continuous transmission end time”) is estimated as the transmission stop period start time, and the transmission stop period The length is estimated to be the same as the transmission prohibition period. As the continuous transmission end time, for example, when there is no data transmission for a predetermined time or more in the communication device, the time when data transmission was last performed can be applied.

(Estimation method 2) The time at which the continuous transmission period has elapsed from the start time of continuous data transmission of the communication device that is the transmission data transmission source is estimated as the transmission stop period start time, and the transmission stop period length is the transmission prohibition period Is the same as

(Estimation method 3) A notification of the transmission stop period start time and the transmission stop period length is received from the communication device that is the transmission data transmission source, and the notification content is retained. In this case, when each wireless communication device 20 performs continuous data transmission on the transfer data (data that the other wireless communication device 20 needs to further transfer) to the other wireless communication device 20, the next transmission is stopped. It is necessary to separately provide a means for notifying the radio communication apparatus 20 of the transmission destination of the scheduled time of the period start time.

  The control unit 204 controls the operation of each unit in the wireless communication device 20 and performs communication control related to the transmission unit 201 and the reception unit 202. The control unit 204 performs communication control in the wireless communication device 20 using the estimation result from the transmission source transmission stop period estimation unit 203.

  The control unit 204 controls the start of data transmission / reception, the control of prohibiting data transmission / reception, and the transfer from the transmission unit 201 when the data received from the reception unit 202 is transfer request data. In addition, the control unit 204 performs control so that data transmission is not performed when it is estimated that the transmission source is not the transmission prohibited period based on the information notified from the transmission source transmission stop period estimation unit 203.

  When the wireless communication device 20 is the transmission side when the control unit 204 controls transmission / reception of transfer data related to multi-hop communication in a frequency band with restrictions related to continuous data transmission, Continuous data transmission is performed with respect to the communication device 20 within the continuous transmission possible period. In addition, when the wireless communication device 20 is on the receiving side, the control unit 204 accumulates the received transfer data while the transmitting-side wireless communication device 20 is capable of continuous transmission, and the transfer data is transferred. Control not to do.

  For example, when data is transmitted from the wireless communication device 20-1 to the wireless communication device 20-3 via the wireless communication device 20-2, the data is continuously transmitted from the wireless communication device 20-1 to the wireless communication device 20-2. During the transmission of data, the wireless communication device 20-2 performs only storage without transferring the received data, and after the wireless communication device 20-1 enters the transmission prohibited period, the wireless communication device 20-3 Start data transfer to In this case, since the data transmitted from the wireless communication device 20-1 is the final destination of the wireless communication device 20-3, the wireless communication device 20-3 does not perform data transfer. It is not necessary to estimate the transmission stop period start time according to 20-2.

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

  FIG. 3 is an explanatory diagram showing an example of communication timing of each wireless communication device 20 in the wireless communication system 10.

  FIG. 3 illustrates a case where data transmission by multi-hop communication is performed from the wireless communication device 20-1 via the wireless communication device 20-2 to the wireless communication device 20-3.

  First, it is assumed that data transmission is performed from the wireless communication device 20-1 to the wireless communication device 20-2 during a continuous transmission possible period (S101).

  In step S101, when data transmission is started from the wireless communication device 20-1 to the wireless communication device 20-2, in the wireless communication device 20-2, the control unit 204 determines whether or not the received data is transfer data. Here, it is assumed that the data is transfer data. Then, in the wireless communication device 20-2, under the control of the control unit 204, the transmission source transmission stop period estimation unit 203 starts the next transmission stop period in the wireless communication device 20-1 that is the transmission data transmission source. The time and the transmission stop period length are estimated, and the estimation result is returned to the control unit 204.

  Next, the wireless communication device 20-2 accumulates the transfer data received from the wireless communication device 20-1 until the estimated transmission stop period start time, and when the transmission stop period start time elapses, the wireless communication device 20 -3 starts transmission of the transfer data accumulated in S-3 (S102).

(A-3) Effects of the First Embodiment According to the first embodiment, the following effects can be achieved.

  In the wireless communication device 20 of the wireless communication system 10, in the above-described example, when data transmission is performed by multi-hop communication from the wireless communication device 20-1 to the wireless communication device 20-3 via the wireless communication device 20-2, In the wireless communication device 20-2, data is accumulated and data transfer to the wireless communication device 20-3 is not started until the wireless communication device 20-1 enters a transmission stop period. As a result, it is possible to prevent overlapping periods of data transmission between the wireless communication device 20-1 and the wireless communication device 20-2, so that collision is avoided, data transfer is performed smoothly, and communication efficiency is improved. Can be improved.

(B) Second Embodiment Hereinafter, a wireless communication apparatus and program according to the present invention and a first embodiment of a wireless communication system will be described in detail with reference to the drawings.

  In the wireless communication system 10 of the first embodiment, when performing multi-hop communication, the wireless communication device 20 continues to transmit data from the wireless communication device 20-1 to the wireless communication device 20-2. -2 is described as performing only storage without transferring received data and starting data transfer to the wireless communication device 20-3 after the wireless communication device 20-1 enters the transmission suspension period.

  However, for example, in the communication system 10, a fourth wireless communication device 20-4 is additionally arranged, and the wireless communication device 20-1 passes through the wireless communication devices 20-2 and 20-3 to the wireless communication device 20-4. When multi-hop communication is performed by repeating data transfer a plurality of times, collision may occur as described later.

  FIG. 4 is an explanatory diagram showing an example of communication timing of each wireless communication device 20 when data transfer is repeated a plurality of times in the wireless communication system 10. Hereafter, the operation | movement which the above-mentioned collision generate | occur | produces is demonstrated using FIG.

  In FIG. 4, the case where the 4th radio | wireless communication apparatus 20-4 is further arrange | positioned in the communication system 10 as mentioned above is assumed. In FIG. 4, the data transmitted from the wireless communication device 20-1 to the wireless communication device 20-2 is transferred to the wireless communication device 20-3, and further re-transferred to the wireless communication device 20-4. It is shown as an example.

  First, data is continuously transmitted from the wireless communication device 20-1 to the wireless communication device 20-2 (S201), and further, the data is transferred from the wireless communication device 20-2 to the wireless communication device 20-3. (S202).

  Since operations in steps S201 and S202 are the same as those in steps S101 and S102 described above, detailed description thereof will be omitted.

  Then, next continuous data transmission from the wireless communication device 20-1 to the wireless communication device 20-2 (S203), and data transfer from the wireless communication device 20-3 to the wireless communication device 20-4 (S204). When this occurs at the same time, as shown in FIG. 4, collision occurs in the wireless communication device 20-2.

  In the second embodiment, a configuration for eliminating the occurrence of collision as shown in FIG. 4 will be described.

(B-1) Configuration of Second Embodiment FIG. 5 is an explanatory diagram showing an overall configuration of a wireless communication system 10A of the second embodiment.

  Four wireless communication devices 20A (20A-1 to 20A-4) are arranged in the wireless communication system 10A. Note that the number of radio communication devices 20A arranged in the radio communication system 10A is not limited.

  The functional configuration inside each wireless communication system 10A can also be described using the block diagram of FIG. In FIG. 1, the reference numerals in parentheses are the reference signs used only in the second embodiment.

  The wireless communication device 20A includes a transmission unit 201, a reception unit 202, a transmission source transmission stop period estimation unit 203A, and a control unit 204A.

  Since the transmission unit 201, the reception unit 202, and the transmission source transmission stop period estimation unit 203 are the same as those in the first embodiment, detailed description thereof is omitted.

  Similarly to the control unit 204 of the first embodiment, when the wireless communication device 20A is the transmission side when the control unit 204A performs transmission data transmission / reception control related to multi-hop communication, the control unit 204A Continuous data transmission is performed within the period in which continuous transmission is possible to the wireless communication device 20A. In addition, when the wireless communication device 20 is on the receiving side, the control unit 204A accumulates the received transfer data while the transmitting-side wireless communication device 20A is continuously transmittable, and the transfer data is transferred. Control not to do.

  In the control unit 204 of the first embodiment, the transmission stop period after the continuous transmission possible period is basically described as being the same period as the transmission prohibition period. However, the control unit 204A of the second embodiment The transmission stop period after the continuous transmission possible period is set to a period longer than the transmission prohibition period.

  In the control unit 204A, for example, the transmission suspension period after the continuous transmission possible period is a period obtained by adding a predetermined period (hereinafter referred to as “transmission suspension period”) to the transmission inhibition period (ie, transmission suspension period = transmission inhibition period). (+ Transmission suspension period).

  The length of the transmission suspension period is not limited, but may be set to be the same as the continuous transmission possible period.

  In addition, when the total length of the transmission suspension period and the transmission prohibition period is shorter than the transmission prohibition period, the transmission suspension period and the transmission prohibition are set so that the sum of the transmission suspension period and the transmission prohibition period is the same as the transmission prohibition period. It is desirable that the length of the period is set. If the continuous transmission possible period and the transmission suspension period can be set to half the length of the transmission prohibition period, the communication efficiency is improved.

  In the second embodiment, for simplicity of explanation, the transmission suspension period and the transmission prohibition period are described as having the same length as the continuous transmission possible period. That is, transmission stop period = continuous transmission possible period × 2.

  In addition, in the control unit 204A, when the destination of data transmitted from the wireless communication device 20A to the other wireless communication device 20A is the other wireless communication device 20, the transmission suspension period is set to the transmission prohibition period. A period that coincides with the transmission prohibition period may be used instead of the long period. In other words, the control unit 204A sets the transmission suspension period only when the data transmitted by the wireless communication device 20A to the other wireless communication device 20A needs to be further transferred by the other wireless communication device 20A. As described above, it may be set to a period longer than the transmission prohibition period.

(B-2) Operation | movement of 2nd Embodiment Next, operation | movement (wireless communication method) of 10 A of radio | wireless communications systems of 2nd Embodiment which has the above structures is demonstrated.

  FIG. 6 is an explanatory diagram showing an example of communication timing of each wireless communication device 20A in the wireless communication system 10A.

  In FIG. 6, the operation when the data transmitted from the wireless communication device 20A-1 to the wireless communication device 20A-2 is transferred to the wireless communication device 20A-3 and further transferred to the wireless communication device 20A-4. An example is shown.

  First, data is continuously transmitted from the wireless communication device 20A-1 to the wireless communication device 20A-2 (S301), and further, the data is transferred from the wireless communication device 20A-2 to the wireless communication device 20A-3. (S302).

  Since the operations in S301 and S302 are the same as those in steps S101 and S102 described above, detailed description thereof will be omitted.

  Then, in the wireless communication device 20A-1, the transmission stop period starts after the end of the continuous transmission of data in step S301 described above. Here, the transmission stop period = transmission prohibited period + transmission suspension period (transmission stop period = continuous transmission). Since the possible period × 2), the transmission suspension period continues even after the transmission prohibition period has elapsed.

  Then, the wireless communication device 20A-1 transmits the data from the wireless communication device 20A-2 to the wireless communication device 20A-3, in addition to the period of the above-described step S302, the wireless communication device 20-3 transmits the data to the wireless communication device 20A. -4 also continues during the period of performing data retransfer (S303) to S-4, and collision as shown in FIG. 4 does not occur.

(B-3) Effect of Second Embodiment In the above-described FIG. 4 using the wireless communication device 20 of the first embodiment, the next continuation from the wireless communication device 20-1 to the wireless communication device 20-2. Since data transmission and data retransfer from the wireless communication device 20-3 to the wireless communication device 20-4 occur at the same time, a collision occurred in the wireless communication device 20-2. On the other hand, in the second embodiment, as shown in FIG. 6, data transmission from the wireless communication device 20 </ b> A- 3 to the wireless communication device 20 </ b> A- 4 is performed by setting the transmission suspension period = transmission prohibited period + transmission suspension period. Thus, it is possible to prevent the timing of data transmission from the wireless communication device 20A-1 from overlapping, reduce the frequency of occurrence of collisions in the communication system 10, and improve the communication efficiency.

(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 each of the above embodiments, each wireless communication device has a mode in which the operation of the communication unit (transmitting unit and receiving unit) of the wireless communication device is stopped while the transmission suspension period is applied. Anyway. For example, by turning off the power supplied to the communication unit (transmission unit and reception unit), power consumption in the wireless communication device can be reduced.

  In each of the above embodiments, each wireless communication device may have a mode in which only the reception unit is operated while the transmission suspension period is applied. In that case, each wireless communication device can reduce the power consumption of the transmission unit during the transmission stop period, so that data transmitted to the own device can be received during the transmission stop period while reducing the power consumption. Therefore, highly efficient communication can be performed.

(C-2) In each of the above-described embodiments, each wireless communication device constituting the communication system performs communication complying with the continuous transmission possible period and the transmission prohibited period in a frequency band with restrictions on continuous data transmission. However, when communication is performed in a frequency band other than that, communication control complying with the above-described restrictions may not be performed.

DESCRIPTION OF SYMBOLS 10 ... Communication system 20, 20-1-20-4 ... Wireless communication apparatus 201 ... Transmission part, 202 ... Reception part, 203 ... Transmission origin transmission prohibition period estimation part, 204 ... Control part.

Claims (12)

Wireless communication 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 when continuously transmitting data to other wireless communication devices In the device
Data transmission stop that holds at least the start time of the data transmission stop period in the transmission source wireless communication device when transfer data that needs to be transferred to the transfer destination wireless communication device is received from the transmission source wireless communication device Period holding means;
When the transfer data that needs to be transferred to the transfer destination wireless communication apparatus is received from the transmission source wireless communication apparatus, the transfer data is accumulated and the data transmission stop held by the data transmission stop period holding means And a data transfer means for starting transmission of the stored transfer data to the transfer destination wireless communication device after the period starts.   The data transmission stop period holding means estimates a time when transmission of transfer data from the transmission source wireless communication apparatus to the wireless communication apparatus is stopped as a start time of a data transmission stop period in the transmission source wireless communication apparatus. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is held.   The data transmission stop period holding means determines the time after the longest data transmission period has elapsed from the start time of transmission of transfer data from the transmission source wireless communication apparatus to the wireless communication apparatus in the transmission source wireless communication apparatus. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus estimates and holds the start time of the data transmission stop period.   The wireless communication apparatus according to claim 1, wherein the data transmission stop period holding unit receives and holds a start time of a data transmission stop period from the transmission source wireless communication apparatus.   When the wireless communication device continuously transmits data to other wireless communication devices, a data transmission stop period for notifying other wireless communication devices of the time when the next data transmission stop period starts in the wireless communication device The wireless communication apparatus according to claim 1, further comprising a notification unit.   The wireless communication apparatus according to claim 1, wherein a period obtained by adding a predetermined data transmission suspension period to the minimum data transmission suspension period is applied as the data transmission suspension period.   The wireless communication apparatus according to claim 6, wherein the data transmission suspension period is the longest data transmission period. The data transmission stop shortest period is the same length as the data transmission longest period,
The wireless communication apparatus according to claim 6, wherein the data transmission suspension period has the same length as the longest data transmission period.   The wireless communication apparatus further includes power saving mode setting means for setting the wireless communication apparatus in a state of lower power consumption compared to a period not in the data transmission stop period while the wireless communication apparatus is in the data transmission stop period. The wireless communication apparatus according to claim 1.   The power saving mode setting means sets the communication unit that communicates with another wireless communication device so that the wireless communication device only performs data reception while the wireless communication device is in the data transmission suspension period. The wireless communication apparatus according to claim 9, wherein: Wireless communication 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 when continuously transmitting data to other wireless communication devices The computer installed in the device
Data transmission suspension that holds at least the start time of the data transmission suspension period in the transmission source wireless communication device when transfer data that needs to be transferred to the transmission destination wireless communication device is received from the transmission source wireless communication device Period holding means;
When the transfer data that needs to be transferred to the transfer destination wireless communication apparatus is received from the transmission source wireless communication apparatus, the transfer data is accumulated and the data transmission stop held by the data transmission stop period holding means A wireless communication program for causing a wireless communication apparatus as a transfer destination to function as data transfer means for starting transmission of accumulated transfer data after a period starts. In a wireless communication system comprising a plurality of wireless communication devices,
A wireless communication system, wherein the wireless communication device according to claim 1 is applied as each of the wireless communication devices.

Images