JP5769582B2 - Wireless communication system, master station wireless communication device, and wireless communication method - Google Patents

Description

  The present invention relates to a radio communication system including a master station radio communication device and a plurality of slave station radio communication devices.

  Conventionally, there are cases where restrictions are imposed on the radio waves emitted by the wireless communication device due to laws and regulations. For example, in the following Non-Patent Documents 1 and 2, the total sum of radio wave transmission times per hour is defined to be 360 seconds or less when the carrier sense time is 128 μs in the 900 MHz band low-power radio. In this way, technical conditions are or are being defined by the frequency band.

  In order to shorten the carrier sense time as much as possible while complying with the regulations of the maximum transmission time that differ depending on the carrier sense time, it is necessary to control to observe the maximum transmission time according to the carrier sense time. A technique for changing the carrier sense time according to the data amount together with the transmission control is disclosed.

Standard ARIB STD-T96 1.1 edition http://www.arib.or.jp/english/html/overview/doc/1-STD-T96v1_1.pdf Outline of technical conditions such as 920MHz band electronic tag system http://www.soumu.go.jp/main_content/000119517.pdf (The full-width “_” in the above URL is actually half-width.)

JP 2010-87669 A

  However, according to the conventional technique, there is no description of a transmission control method for complying with the maximum transmission time linked with polling communication in a system that performs polling communication. Therefore, if the maximum transmission time is observed in a system that performs polling communication, the maximum transmission time may be exceeded due to continuous polling for a specific time, and radio wave transmission or polling communication may not be started for a certain period of time. There was a problem that polling communication might be interrupted due to the radio wave transmission time being exceeded.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a wireless communication system that can efficiently perform polling communication without interruption.

  In order to solve the above-described problems and achieve the object, the present invention provides a wireless communication system that performs polling between a master station wireless communication device and a plurality of slave station wireless communication devices, wherein the master station wireless communication The apparatus controls polling transmission to the target slave station radio communication apparatus, and notifies polling start and polling end, and starts polling based on the polling start and polling end notifications from the polling control means. Radio wave transmission time control means for calculating a cumulative transmission time during which radio waves are transmitted during a polling time from the end to the end, and the slave station radio communication device transmits a polling response to the polling transmission to the master station radio communication device Polling response means, and a port of the master station wireless communication device. The polling control means uses the accumulated transmission time, the maximum radio wave transmission time defined per predetermined time, and the predetermined time to determine a non-polling time during which polling is not performed until the next polling is started. It is characterized by setting.

  According to the present invention, in wireless communication in which the maximum transmission time is specified, there is an effect that polling communication can be performed efficiently without interruption while satisfying the maximum transmission time specification.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication system according to the first embodiment. FIG. 2 is a block diagram showing the configuration of the master station radio communication apparatus. FIG. 3 is a block diagram showing a configuration of the slave station wireless communication apparatus. FIG. 4 is a sequence diagram illustrating an operation of polling communication in the wireless communication system according to the first embodiment. FIG. 5 is a flowchart showing a control process of polling communication. FIG. 6 is a diagram illustrating a configuration example of a wireless communication system according to the second embodiment. FIG. 7 is a sequence diagram illustrating an operation of polling communication in the wireless communication system according to the second embodiment.

  Embodiments of a wireless communication system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system according to the present embodiment. The radio communication system includes a master station radio communication device 1, a slave station radio communication device 2-1, a slave station radio communication device 2-2, and a slave station radio communication device 2-3. Between master station radio communication apparatus 1 and slave station radio communication apparatus 2-1, between master station radio communication apparatus 1 and slave station radio communication apparatus 2-2, and between master station radio communication apparatus 1 and slave station radio communication Each of the devices 2-3 is connected by a wireless link. The master station radio communication device 1 performs polling communication with the slave station radio communication devices 2-1 to 2-3 at regular intervals or at arbitrary time intervals.

  Next, the configuration of the master station wireless communication device 1 will be described. FIG. 2 is a block diagram showing a configuration of the master station radio communication apparatus 1. The master station wireless communication device 1 includes a wireless communication unit 11, a data reception unit 12, a polling control unit 13, a data transmission unit 14, a radio wave transmission time control unit 15, and a radio wave transmission control unit 16.

  The wireless communication unit 11 performs wireless communication with the slave station wireless communication devices 2-1 to 2-3. Polling transmission is performed to the slave station wireless communication apparatuses 2-1 to 2-3, and a polling response to the polling transmission is received from the slave station wireless communication apparatuses 2-1 to 2-3.

  The data receiving unit 12 receives the received polling response data, confirms that the data is normal, transfers the data to the host device or application, and notifies the polling control unit 13 of normal reception.

  The polling control unit 13 sequentially issues data transmission instructions for polling communication, and confirms the normality of polling communication by receiving polling responses from the slave station wireless communication devices 2-1 to 2-3. Further, the start time and end time of polling are notified to the radio wave transmission time control unit 15, and the non-polling time is controlled according to the radio wave transmission time notification within the polling period from the radio wave transmission time control unit 15.

  The data transmission unit 14 transfers data from a higher-level device or an application to the radio wave transmission control unit 16 according to an instruction from the polling control unit 9.

  The radio wave transmission time control unit 15 sets the upper limit of the accumulated time for transmitting radio waves per predetermined time as the maximum transmission time, and performs radio wave transmission (per predetermined time) between the present time or a specified time and a predetermined time before. Radio wave transmission time counting means for measuring the accumulated transmission time, and when the accumulated transmission time exceeds the maximum transmission time, the radio transmission stop is instructed.

  The radio wave transmission control unit 16 controls radio wave transmission and radio wave stop according to instructions from the radio wave transmission time control unit 15.

  Next, the configuration of the slave station wireless communication devices 2-1 to 2-3 will be described. FIG. 3 is a block diagram illustrating a configuration of the slave station wireless communication device 2-1. The slave station radio communication device 2-1 includes a radio communication unit 21, a data reception unit 22, a polling response control unit 23, a data transmission unit 24, a radio wave transmission time control unit 25, a radio wave transmission control unit 26, Is provided. In addition, although demonstrated using the slave station radio | wireless communication apparatus 2-1, the slave station radio | wireless communication apparatuses 2-2 and 2-3 are also the same structures.

  The wireless communication unit 21 performs wireless communication with the master station wireless communication device 1. The polling transmission data is received from the master station wireless communication device 1 and a polling response to the polling transmission is transmitted to the master station wireless communication device 1.

  The data receiving unit 22 receives the polling transmission data, confirms that the data is normal, and then transfers the data to the host device or application, and also indicates that the polling transmission data has been received normally. To notify.

The polling response control unit 23 performs control such that data from the host device or application is transmitted as polling response data for polling transmission from the master station wireless communication device 1.
The polling response control unit 23 may request a polling response for polling transmission from the master station wireless communication device 1 to the host device or application, and the host device or application may return polling response data.

  The data transmission unit 24 transfers data from the host device or application to the radio wave transmission control unit 26 in accordance with an instruction from the polling response control unit 23.

  The radio wave transmission time control unit 25 sets the upper limit of the accumulated time for transmitting radio waves per predetermined time as the maximum transmission time, and measures the accumulated transmission time during which radio wave transmission was performed between the present time or a specified time and a predetermined time before. Radio wave transmission time counting means for instructing to stop radio wave transmission when the accumulated transmission time exceeds the maximum transmission time.

  The radio wave transmission control unit 26 controls radio wave transmission and radio wave stop according to an instruction from the radio wave transmission time control unit 25.

  Next, polling communication control processing in the wireless communication system shown in FIG. 1 will be described. FIG. 4 is a sequence diagram showing an operation of polling communication in the wireless communication system of the present embodiment. Here, the period during which polling communication is performed from the master station radio communication device 1 to the slave station radio communication devices 2-1 to 2-3 is the polling time, and the period from the end of the polling time to the start of the next polling time is the non-polling time. The period from the start of the polling time to the start of the next polling time, that is, the period combining one polling time and one non-polling time is defined as a polling period.

  FIG. 5 is a flowchart showing control processing of polling communication in the wireless communication system. First, as a premise of the control processing of polling communication, in the master station wireless communication device 1 and the slave station wireless communication devices 2-1 to 2-3, the maximum radio wave transmission time per predetermined time is limited to a predetermined condition. Yes. For example, when the carrier sense time is 128 μs and the total radio wave transmission time per hour is 360 seconds or less, the master station wireless communication device 1 and slave station wireless communication devices 2-1 to 2-3 The radio wave transmission time control unit 15 and the radio wave transmission time control unit 25 always measure the radio wave transmission time per hour. When the sum of radio wave transmission times exceeds 360 seconds during radio wave transmission, the radio wave transmission time control unit 15 and the radio wave transmission time control unit 25 transmit radio waves to the radio wave transmission control unit 16 and the radio wave transmission control unit 26, respectively. By issuing a stop instruction, control for stopping radio wave transmission from the radio wave transmission control unit 16 and the radio wave transmission control unit 26 is performed.

  Next, as shown in FIG. 1 and FIG. 4, in order to start polling communication under the initiative of the master station wireless communication device 1, first, in the master station wireless communication device 1, the data transmission unit is controlled under the control of the polling control unit 13. 14. Perform polling transmission 30-1 to the slave station wireless communication device 2-1 via the radio wave transmission control unit 16 and the wireless communication unit 11 (step S1). At this time, since the slave station wireless communication device 2-1 is the first slave station wireless communication device (step S2: Yes), the polling control unit 13 notifies the radio wave transmission time control unit 15 of the polling start time, The radio wave transmission time control unit 15 starts measuring the radio wave transmission time (step S3).

  In the slave station wireless communication device 2-1, the polling response control unit 23 transmits data to the polling transmission 30-1 from the master station wireless communication device 1 received via the wireless communication unit 21 and the data receiving unit 22. The polling response 40-1 is transmitted to the master station wireless communication device 1 via the unit 24, the radio wave transmission control unit 26, and the wireless communication unit 21 (step S4).

  In the master station wireless communication device 1, the polling control unit 13 receives the polling response 40-1 through the wireless communication unit 11 and the data receiving unit 12. Here, when the polling for all the slave station wireless communication devices to be polled has not been completed (step S5: No), the master station wireless communication device 1 returns to the above step S1 and the next slave station wireless communication is completed. Polling transmission is performed with respect to the communication device (step S1), and the slave station wireless communication device that has received the polling transmission repeatedly transmits the polling response to the master station wireless communication device 1 (step S4).

  Specifically, polling transmission 30-2 is performed from the master station wireless communication device 1 to the slave station wireless communication device 2-2, and the slave station wireless communication device 2-2 responds to the polling response to the master station wireless communication device 1 40-2, and further, polling transmission 30-3 is performed from the master station radio communication apparatus 1 to the slave station radio communication apparatus 2-3, and the slave station radio communication apparatus 2-3 responds to the master station radio communication apparatus 1. A polling response 40-3 is performed. Note that in the master station wireless communication device 1, the slave station wireless communication device 2-2 and the subsequent ones are not the first slave station wireless communication device (step S2: No), so the process of starting the measurement of the radio wave transmission time (step S3) ) Is not implemented here.

  When polling for all the slave station wireless communication devices to be polled is completed (step S5: Yes), in the master station wireless communication device 1, the polling control unit 13 sets the polling end time to the radio wave transmission time control unit. 15, the radio wave transmission time control unit 15 ends the measurement of the radio wave transmission time (step S <b> 6). Polling communication from the master station wireless communication device 1 to all the slave station wireless communication devices 2-1 to 2-3 is continuously performed, and a series of polling communication is completed. As shown in FIG. 4, after the master station wireless communication device 1 performs polling transmission 30-1 to the slave station wireless communication device 2-1, the slave station wireless communication device 2-3 is connected to the master station wireless communication device 1. The period until the polling response 40-3 is performed, that is, the period defined by the polling start time notification to the polling end time notification is defined as the polling time.

  In this polling communication, in the master station wireless communication device 1, the accumulated transmission time during which the radio wave transmission time control unit 15 was transmitting radio waves during the polling time according to the polling start time and end time notifications from the polling control unit 13. Is obtained (step S7). The radio wave transmission time control unit 15 notifies the polling control unit 13 of the calculated accumulated transmission time as the radio wave transmission time within the polling period.

  The polling control unit 13 polls the polling time using the radio wave transmission time within the polling period notified from the radio wave transmission time control unit 15, the predetermined time, and the maximum radio wave transmission time at the predetermined time. A non-polling time during which no polling communication is performed from the end time to the next polling start time is set (step S8). By taking a sufficient non-polling time and ensuring a margin for the maximum radio wave transmission time at the next polling time, the master station radio communication device 1 performs polling communication so as not to cause interruption while satisfying the radio wave transmission conditions. Can be controlled.

  Specifically, in the master station wireless communication device 1, the polling control unit 13 sets a non-polling time that satisfies the following expression (1) for each polling period.

Radio transmission time within polling cycle / (polling time + non-polling time)
≦ Radio wave transmission time ratio specified in radio wave transmission conditions (1)

  In all polling cycles, control is performed such that the ratio of the time for transmitting radio waves is equal to or less than the radio wave transmission time ratio defined by the radio wave transmission conditions. As a result, in a radio communication system, radio wave transmission time exceeded due to continuous polling for a specific time while observing the maximum transmission time, radio wave transmission or polling communication cannot be started for a certain period of time, and radio wave transmission during polling communication It is possible to prevent polling communication from being interrupted due to excessive time, and polling communication can be performed efficiently.

  For example, when the carrier sense time is 128 μs, the predetermined time is 1 hour (3600 seconds), and the sum of the radio wave transmission times per hour (maximum radio wave transmission time) is 360 seconds or less, the radio wave transmission time ratio is 0.1. Since (= 360/3600), the above equation (1) can be expressed as the following equation (2).

Radio transmission time within polling cycle / (polling time + non-polling time) ≤ 0.1
... (2)

  In the master station wireless communication device 1, the polling control unit 13 sets a non-polling time that satisfies the above equation (2), and starts the next polling communication after the non-polling time has elapsed.

  In FIG. 4, at the next polling time, the master station wireless communication device 1 performs polling transmission 31-1 to the slave station wireless communication device 2-1, and is the same as the previous polling communication. The device 2-3 performs processing until the master station wireless communication device 1 performs the polling response 41-3.

Here, in the master station wireless communication device 1, when radio wave transmission is performed only during the polling time, or the radio wave transmission time during the non-polling time is a minute time compared to the radio wave transmission time during the polling time. In this case, it can be expressed as in the above formulas (1) and (2).
When the radio wave transmission time in the non-polling time is not negligible with respect to the radio wave transmission time in the polling time, for example, the numerator on the left side of the above equation (1) is transformed to the following equation (3). Thus, the non-polling time can be obtained.

(Radio wave transmission time during polling time + Radio wave transmission time during non-polling time) /
(Polling time + non-polling time)
≦ Radio wave transmission time ratio specified in radio wave transmission conditions (3)

  In this case, the radio wave transmission time control unit 15 of the master station radio communication device 1 calculates the accumulated transmission time including the radio wave transmission time during the non-polling time. Here, if the radio wave transmission time scheduled for the non-polling time to be set in the future is known, the time may be set as the radio wave transmission time during the non-polling time, but is not limited thereto. For example, the radio wave transmission time during the non-polling time of the previous polling cycle may be used as the radio wave transmission time during the non-polling time when the next non-polling time is obtained. In addition, if the radio wave transmission time during the non-polling time stably shifts within a certain range, the predicted maximum value may be set as the radio wave transmission time during the non-polling time. Thereby, the non-polling time can be set in consideration of the radio wave transmission time during the non-polling time.

  Note that there may be a case where normal communication cannot be performed due to deterioration in wireless quality from the start to the end of polling communication. In this case, each transmission process may be regarded as completed by retransmission or transmission abortion.

  As described above, in this embodiment, the master station wireless communication device obtains the accumulated transmission time during which the radio wave is transmitted within the polling period, and adds the accumulated transmission time, the polling time and the non-polling time. The non-polling time is set so that the ratio between the maximum radio wave transmission time defined in the predetermined time and the predetermined time is smaller. As a result, the master station wireless communication device can perform polling communication efficiently without interruption, and radio wave transmission or polling communication cannot be started for a certain period of time, or polling communication is interrupted due to excessive radio wave transmission time during polling communication. Can be avoided.

  In addition, although the case where polling is performed from the master station wireless communication device 1 to all the slave station wireless communication devices 2-1 to 2-3 has been described, the present invention is not limited to this. For example, when only a part of slave station wireless communication devices are subject to polling, or only by continuous transmission from the master station wireless communication device 1 to the slave station wireless communication devices 2-1 to 2-3, The present invention can also be applied to a case where no response is made from the wireless communication devices 2-1 to 2-3.

  Further, the present invention is not limited to polling communication, and can be applied to, for example, individual unicast communication, multicast communication, broadcast communication, and other control system communication and polling communication.

Embodiment 2. FIG.
FIG. 6 is a diagram illustrating a configuration example of a wireless communication system according to the present embodiment. The wireless communication system includes a master station wireless communication device 1, a slave station wireless communication device 2-1, a slave station wireless communication device 2-2, a slave station wireless communication device 2-3, and a slave station wireless communication device 2- 4 and a slave station wireless communication device 2-5. Between master station radio communication apparatus 1 and slave station radio communication apparatus 2-1, between master station radio communication apparatus 1 and slave station radio communication apparatus 2-2, and between master station radio communication apparatus 1 and slave station radio communication Each of the devices 2-3 is connected by a wireless link. The slave station wireless communication device 2-1 and the slave station wireless communication device 2-4 and the slave station wireless communication device 2-2 and the slave station wireless communication device 2-5 are respectively connected by wireless links. It is connected. The configuration of the slave station wireless communication devices 2-4 and 2-5 is the same as that of the slave station wireless communication devices 2-1 to 2-3.

  The master station wireless communication device 1 performs polling communication with the slave station wireless communication devices 2-1 to 2-3 by direct communication at regular intervals or at arbitrary time intervals. The master station wireless communication device 1 performs polling communication with the slave station wireless communication devices 2-4 and 2-5 by multi-hop communication at regular intervals or at arbitrary time intervals.

  FIG. 7 is a sequence diagram showing an operation of polling communication in the wireless communication system of the present embodiment. A period for performing polling communication from the master station radio communication device 1 to the slave station radio communication devices 2-1 to 2-5 is set as a polling time, and a period from the end of the polling time to the start of the next polling time is set as a non-polling time. A period from the start to the start of the next polling time is defined as a polling cycle.

  Specifically, polling communication between the master station radio communication device 1 and the slave station radio communication devices 2-1 to 2-3 is the same as that in the first embodiment (see FIG. 4). Next, polling transmission 50-1 is performed from the master station wireless communication device 1 to the slave station wireless communication device 2-1, and the slave station wireless communication device 2-1 polls transmission 60-1 to the slave station wireless communication device 2-4. In response to this, the slave station wireless communication device 2-4 makes a polling response 70-1 to the slave station wireless communication device 2-1, and the slave station wireless communication device 2-1 polls the master station wireless communication device 1 Perform 80-1. Also, polling transmission 50-2 is performed from the master station wireless communication device 1 to the slave station wireless communication device 2-2, and the slave station wireless communication device 2-2 performs polling transmission 60-2 to the slave station wireless communication device 2-5. In response, the slave station wireless communication device 2-5 sends a polling response 70-2 to the slave station wireless communication device 2-2, and the slave station wireless communication device 2-2 sends a polling response 80 to the master station wireless communication device 1. -2.

  Thereafter, in the master station wireless communication device 1, the polling control unit 13 sets a non-polling time and starts the next polling communication after the non-polling time has elapsed.

  In FIG. 7, at the next polling time, the master station wireless communication device 1 performs polling transmission 31-1 to the slave station wireless communication device 2-1, and is similar to the previous polling communication. The device 2-2 performs processing until the polling response 81-2 is made to the master station wireless communication device 1.

  Thus, since the polling time and the non-polling time can be defined as in the first embodiment, the master station radio communication device 1 can set the non-polling time using the above equation (1) and the like. Thereby, even in a multi-hop wireless communication system, polling communication can be performed efficiently without interruption.

  As described above, the radio communication system according to the present invention is useful for a system including a master station radio communication device and a plurality of slave station radio communication devices, and in particular, the master station radio communication device and a plurality of slave station radio communications. This is suitable for polling with the device.

DESCRIPTION OF SYMBOLS 1 Master station radio | wireless communication apparatus 2-1, 2-2, 2-3, 2-4, 2-5 Slave station radio | wireless communication apparatus 11 Wireless communication part 12 Data reception part 13 Polling control part 14 Data transmission part 15 Radio wave transmission time Control unit 16 Radio wave transmission control unit 21 Wireless communication unit 22 Data reception unit 23 Polling response control unit 24 Data transmission unit 25 Radio wave transmission time control unit 26 Radio wave transmission control unit

Claims (9)

A wireless communication system that performs polling between a master station wireless communication device and a plurality of slave station wireless communication devices,
The master station wireless communication device
Polling control means for controlling polling transmission to the target slave station wireless communication device and notifying polling start and polling end;
A radio wave transmission time control unit that calculates a cumulative transmission time during which a radio wave is transmitted in a polling time from the polling start to the end based on a polling start and polling end notification from the polling control unit;
With
The slave station wireless communication device
Polling response means for transmitting a polling response to the polling transmission to the master station wireless communication device;
With
The polling control means of the master station wireless communication device uses the cumulative transmission time, the maximum radio wave transmission time defined per predetermined time, and the predetermined time to perform polling until the next polling is started. Set non-polling time,
A wireless communication system. The polling control means of the master station wireless communication device is configured to perform non-polling in which a ratio of the cumulative transmission time to a polling cycle obtained by adding the polling time and the non-polling time is equal to or less than a ratio of the maximum radio wave transmission time to the predetermined time. Find the time and set the next non-polling time,
The wireless communication system according to claim 1. The radio wave transmission time control means of the master station radio communication device includes the radio wave transmission time during the non-polling time in the cumulative transmission time.
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. The master station radio communication device in a radio communication system that performs polling between a master station radio communication device and a plurality of slave station radio communication devices,
Polling control means for controlling polling transmission to the target slave station wireless communication device and notifying polling start and polling end;
A radio wave transmission time control unit that calculates a cumulative transmission time during which a radio wave is transmitted in a polling time from the polling start to the end based on a polling start and polling end notification from the polling control unit;
With
The polling control means uses the accumulated transmission time, the maximum radio wave transmission time defined per predetermined time, and the predetermined time, and then performs non-polling time until polling is started next Set
A master station wireless communication apparatus. The polling control means obtains a non-polling time in which a ratio of the cumulative transmission time to a polling period obtained by adding the polling time and the non-polling time is equal to or less than a ratio of the maximum radio wave transmission time to the predetermined time. Set a non-polling time for
The master station radio communication apparatus according to claim 4. The radio wave transmission time control means includes the radio wave transmission time during the non-polling time in the cumulative transmission time.
The master station radio communication apparatus according to claim 4 or 5, A wireless communication method in a wireless communication system that performs polling between a master station wireless communication device and a plurality of slave station wireless communication devices,
A polling transmission step in which the master station wireless communication device performs polling transmission to a target slave station wireless communication device;
Radio wave transmission time measurement start step for starting measurement of radio wave transmission time at the start of polling by the master station wireless communication device,
A polling response step in which the target slave station wireless communication device transmits a polling response to the polling transmission to the master station wireless communication device;
Radio wave transmission time measurement ending step in which the master station radio communication device ends measurement of radio wave transmission time when polling to all polling target slave station radio communication devices is completed,
A cumulative transmission time calculating step in which the master station wireless communication device calculates a cumulative transmission time in which a radio wave is transmitted in a polling time from a polling start to an end;
The master station wireless communication device does not perform polling until the next polling is started using the accumulated transmission time, the maximum radio wave transmission time defined per predetermined time, and the predetermined time. A non-polling configuration step for setting the polling time;
A wireless communication method comprising: In the non-polling setting step, a ratio of the accumulated transmission time to a polling period obtained by adding the polling time and the non-polling time is determined to be a non-polling time that is equal to or less than a ratio of the maximum radio wave transmission time to the predetermined time. Set the next non-polling time,
The wireless communication method according to claim 7. In the cumulative transmission time calculating step, the radio transmission time during the non-polling time is included in the cumulative transmission time.
The wireless communication method according to claim 7 or 8, wherein

Images