Wireless communication device, method, and program

Abstract

A wireless communication device is provided that can estimate the extent to which data can be transmitted within an allowable transmission time. [Solution] The wireless communication device includes a wireless communication unit that performs wireless LAN communication, an acquisition unit that acquires statistical data including an MCS (Modulation and Coding Scheme) index and transmission data volume of transmission data previously transmitted by the wireless communication unit, and an estimation unit that estimates the transmittable data volume or the transmittable number of times the transmission data can be transmitted within an allowable transmission time based on the statistical data.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device, method, and program. [Background technology]

[0002] Patent Document 1 discloses a technology that limits the amount of data that can be transmitted per unit time, thereby avoiding exceeding the total transmission time allocated to a communication path and ensuring transmission opportunities for urgent applications. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-050940 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, wireless LAN communications may impose limitations on transmission time, but even when transmitting the same data, the applied MCS (Modulation and Coding Scheme) changes depending on factors such as the distance between devices, making it difficult to determine how much data can be transmitted within the allowed transmission time.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its main purpose is to provide a wireless communication device, method, and program that can estimate the extent to which data can be transmitted within an allowable transmission time. [Means for solving the problem]

[0006] In order to solve the above problem, a wireless communication device according to one aspect of the present invention includes a wireless communication unit that performs wireless LAN communication, an acquisition unit that acquires statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by the wireless communication unit, and an estimation unit that estimates, based on the statistical data, an amount of transmittable data that can be transmitted within an allowable transmission time or an allowable number of times that the transmission data can be transmitted. This makes it possible to estimate the extent to which data can be transmitted within the allowable transmission time.

[0007] In the above aspect, the estimation unit may estimate the amount of transmittable data that can be transmitted within the remaining time of the permissible transmission time or the number of times that transmission can be performed. This makes it possible to estimate the extent to which data can be transmitted within the remaining time.

[0008] In the above aspect, the present invention may further include a determination unit that determines the number of consecutive transmissions or retransmissions of the transmission data based on the transmittable data amount or the transmittable number of times. This makes it possible to determine the number of consecutive transmissions or retransmissions of the transmission data based on the estimation result.

[0009] In the above aspect, the estimation unit may further include a determination unit that estimates the amount of transmittable data or the number of times that transmissions can be made within the remaining time after transmission of the transmission data within the permissible transmission time, and determines the number of times that the transmission data can be retransmitted based on the amount of transmittable data or the number of times that transmissions can be made. This makes it possible to estimate the extent to which data can be transmitted within the remaining time, and to determine the number of times that the transmission data can be continuously transmitted or retransmitted based on the estimation result.

[0010] In the above aspect, the wireless communication unit may perform 802.11ah wireless LAN communication, which makes it possible to transmit transmission data to a remote upper communication device.

[0011] In the above aspect, the wireless communication unit may further include a sensor, and the wireless communication unit may periodically transmit sensor data detected by the sensor to a higher-level communication device, thereby making it possible to estimate the extent to which the sensor data can be transmitted within the transmission allowable time.

[0012] In the above aspect, the present invention may further include a determination unit that determines the MCS index of the transmission data based on the transmittable data amount or the transmittable number of times. This makes it possible to determine the MCS index based on the estimation result.

[0013] In another aspect of the present invention, a method acquires statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication, and estimates the amount of transmittable data or the number of times that the transmission data can be transmitted within an allowable transmission time based on the statistical data. This makes it possible to estimate the extent to which data can be transmitted within the allowable transmission time.

[0014] According to another aspect of the present invention, a program causes a computer to acquire statistical data including an MCS (Modulation and Coding Scheme) index and an amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication, and estimate, based on the statistical data, an amount of transmittable data that can be transmitted within an allowable transmission time or an allowable number of times that the transmission data can be transmitted. This makes it possible to estimate the extent to which data can be transmitted within the allowable transmission time. [Effects of the Invention]

[0015] According to the present invention, it is possible to estimate the extent to which data can be transmitted within the permissible transmission time. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 illustrates an example of a wireless communication system. [Figure 2] FIG. 1 illustrates an example of an access point. [Figure 3] FIG. 1 illustrates an example of a relay device. [Figure 4] FIG. 2 illustrates an example of a sensor terminal. [Figure 5] FIG. 2 illustrates an example of a control unit. [Figure 6] FIG. 10 is a diagram illustrating an example of statistical data. [Figure 7] FIG. 10 is a diagram illustrating an example of a method for determining the number of retransmissions. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions thereof may be omitted as appropriate.

[0018] 1 is a block diagram showing an example of the configuration of a wireless communication system 100. The wireless communication system 100 includes an access point 1, one or more relay devices 2A and 2B, and a sensor terminal 3. The wireless communication system 100 further includes a management server 4.

[0019] The access point 1 and the management server 4 are connected to a communication network such as a wired LAN or the Internet, and are capable of network communication with each other.

[0020] The relay devices 2A and 2B relay wireless communications between the access point 1 and the sensor terminal 3. Hereinafter, the relay devices 2A and 2B are also collectively referred to as "relay devices 2." The relay device 2 is also called a repeater.

[0021] The sensor terminal 3 is a wireless communication terminal equipped with a sensor, and periodically transmits sensor data detected by the sensor. The sensor terminal 3 is a so-called IoT device, and is also called a station.

[0022] The sensor of the sensor terminal 3 is, for example, a light sensor, an image sensor, a pressure sensor, a temperature sensor, a humidity sensor, or an acceleration sensor.

[0023] The sensor data is transmitted from the sensor terminal 3 to the relay device 2B, further transmitted from the relay device 2B to the relay device 2A, further transmitted from the relay device 2A to the access point 1, and further transmitted from the access point 1 to the management server 4.

[0024] The management server 4 centrally manages the settings of the access points 1, relay devices 2, and sensor terminals 3. The management server 4 transmits setting information to these devices and receives status information from these devices.

[0025] The access point 1, the relay device 2, and the sensor terminal 3 are capable of wireless LAN communication using the 920 MHz band. Specifically, the access point 1, the relay device 2, and the sensor terminal 3 perform wireless LAN communication in accordance with the IEEE standard 802.11ah.

[0026] The 920 MHz band is suitable for long-distance communication, and furthermore, by having a relay device 2 interposed in series between the access point 1 and the sensor terminal 3, the wireless communication system 100 is able to collect sensor data from remote sensor terminals 3.

[0027] Therefore, the wireless communication system 100 is suitable for applications in which information such as temperature, humidity, or video images is collected and managed at each location in a wide area such as farmland.

[0028] However, in the 920MHz band, the Radio Law limits the transmission time per unit time (also called transmission duty) to 10%. Specifically, the transmission time is limited to 6 minutes per hour.

[0029] 2 is a block diagram showing an example of the configuration of the access point 1. The access point 1 includes a control unit 10, a wireless communication unit 11, and a wired communication unit 12.

[0030] The control unit 10 is a computer including a CPU, RAM, ROM, nonvolatile memory, an input / output interface, etc. The CPU executes information processing in accordance with a program loaded from the ROM or nonvolatile memory to the RAM.

[0031] The wireless communication unit 11 performs 802.11ah wireless LAN communication. The wired communication unit 12 is connected to a wired LAN. The control unit 10 bridges the wireless communication device connected to the wireless communication unit 11 and the wired LAN connected to the wired communication unit 12.

[0032] 3 is a block diagram showing an example of the configuration of the relay device 2. The relay device 2 includes a control unit 20 and a wireless communication unit 21. The control unit 20 and the wireless communication unit 21 have the same configurations as the control unit 10 and the wireless communication unit 11 of the access point 1.

[0033] The access point 1 and the relay device 2 may be devices with the same configuration, and may function as either the access point 1 or the relay device 2 by switching the mode.

[0034] 4 is a block diagram showing an example of the configuration of the sensor terminal 3. The sensor terminal 3 includes a control unit 30, a wireless communication unit 31, and a sensor 33. The control unit 30 and the wireless communication unit 31 have the same configurations as the control unit 10 and the wireless communication unit 11 of the access point 1 described above.

[0035] The control unit 30 generates sensor data based on the signal output from the sensor 33. The number of sensors 33 is not limited to one, and may be multiple.

[0036] The access point 1, the relay device 2, and the sensor terminal 3 are equipped with solar panels (not shown), are installed outdoors, and operate by receiving power from the solar panels.

[0037] As mentioned above, in the 920 MHz band where the 802.11ah standard can be used, the Radio Law limits the transmission duty to 10%. Hereinafter, the time allowed for data transmission under this limit will be referred to as the "allowed transmission time."

[0038] In wireless LAN communication, when transmitting data, an MCS (Modulation and Coding Scheme) index is set appropriately. As shown in FIG. 6, there are various MCS indices such as MCS0 to MCS10.

[0039] As for the modulation method, BPSK is used for MCS0, QPSK is used for MCS1 and MCS2, 16-QAM is used for MCS3 and MCS4, and 64-QAM is used for MCS5 to MCS7.

[0040] For example, if the distance between devices is short, MSC7, MSC8, etc., which have a low packet time occupancy rate, will be selected, allowing large amounts of data to be transmitted in a short time. On the other hand, if the distance between devices is long, MSC0, etc., which have a high packet time occupancy rate, will be selected.

[0041] Therefore, even when transmitting the same data, if the applied MCS index differs, the time occupancy rate of the packet differs, making it difficult to determine how much data can be transmitted within the allowed transmission time.

[0042] Therefore, in this embodiment, as will be described below, the extent to which data can be transmitted within the transmission allowable time is estimated, and the number of times data can be retransmitted is made variable, thereby improving communication reliability.

[0043] 5 is a block diagram showing an example of the configuration of the control unit 30 of the sensor terminal 3. Here, the control unit 30 of the sensor terminal 3 is taken as an example, but the control unit 20 of the relay device 2 may also be configured in the same way.

[0044] The control unit 30 includes a transmission processing unit 41, a statistical data acquisition unit 42, a transmittable amount estimation unit 43, and a retransmission count determination unit 44. These functional units are realized by the control unit 30 executing information processing in accordance with a program.

[0045] The control unit 30 can also access a statistical data storage unit 49. The statistical data storage unit 49 may be provided in the memory of the control unit 30 or may be provided outside the control unit 30.

[0046] The transmission processing unit 41 periodically transmits sensor data detected by the sensor 33 to the relay device 2B via the wireless communication unit 31. The cycle for transmitting the sensor data is set to match the cycle at which the permissible transmission time arrives, for example.

[0047] The statistical data acquisition unit 42 acquires statistical data from the statistical data storage unit 48. The statistical data is data including the MCS index and the amount of transmission data transmitted by the wireless communication unit 31 in the past.

[0048] 6, the statistical data includes, for example, an MCS index, the number of transmitted packets, and the amount of transmitted data, and indicates, for example, how much data was transmitted at which MCS index during one or more recent permitted transmission times. Generally, a memory for such statistical data is built into a wireless LAN chip.

[0049] The transmittable amount estimation unit 43 estimates the amount of transmittable data that can be transmitted within the permissible transmission time based on the statistical data acquired by the statistical data acquisition unit 42. However, the transmittable amount estimation unit 43 may also estimate the number of times that the transmission data can be transmitted.

[0050] The statistical data indicates the average time occupancy rate of transmission packets per unit time (e.g., one hour), so the transmittable amount estimation unit 43 can estimate the transmittable amount of data that can be transmitted within the permissible transmission time based on the usage history of the MCS index.

[0051] The retransmission count determination unit 44 determines the number of retransmissions of the transmission data based on the estimation result by the transmittable amount estimation unit 43. However, in the case of a protocol that does not send an ACK response or one-way communication, the retransmission count determination unit 44 may determine the number of consecutive transmissions of the transmission data.

[0052] 7 is a flow diagram showing an example of the procedure of a method realized in the wireless communication system 100. The diagram mainly shows the process related to determining the number of retransmissions. The control unit 30 of the sensor terminal 3 executes the information processing shown in the diagram in accordance with a program. The control unit 20 of the relay device 2 may also execute the same information processing.

[0053] First, after the control unit 30 is started (S11), it is in an idle state until the permitted transmission time comes (S12).

[0054] Next, when the transmission allowable time arrives, the control unit 30 transmits the sensor data to the higher-level communication device (S13, processing as the transmission processing unit 41).

[0055] Next, the control unit 30 acquires statistical data from the statistical data storage unit 49 (S14, processing as the statistical data acquisition unit 42).

[0056] Next, the control unit 30 calculates the number of retransmissions n that can be performed to retransmit the sensor data within the remaining time of the permissible transmission time (S15, processing as the transmittable amount estimation unit 43 and the retransmission number determination unit 44).

[0057] The spatial occupancy time required to transmit a given amount of data (e.g., one packet) for each MCS index can be calculated in advance, and by using this, it is possible to calculate, for each MCS index, the amount of data that can be retransmitted within the remaining time allowed for transmission, as well as the number of retransmissions that can be performed.

[0058] Among these, the number of retransmissions possible for the MCS index with the most frequently used MCS index is selected as the "number of retransmissions possible n." If there are multiple MCS indexes with the most frequently used MCS indexes, the number of retransmissions possible is calculated based on the ratio of the number of packets or amount of data transmitted.

[0059] Next, the control unit 30 determines whether or not an ACK (acknowledgement) has been received (S16).

[0060] If ACK is received (S16: YES), the control unit 30 performs a transmission completion process (S17) and returns to the idle state (S12).

[0061] On the other hand, if ACK is not received (S16: NO), the control unit 30 determines whether the number of retransmissions exceeds the allowable number of retransmissions n or is equal to or less than the allowable number of retransmissions n (S18).

[0062] If the number of retransmissions exceeds the allowable number of retransmissions n (S18: YES), the control unit 30 performs a transmission completion process (S17) and returns to the idle state (S12).

[0063] On the other hand, if the number of retransmissions is equal to or less than the allowable number of retransmissions n (S18: NO), the control unit 30 retransmits the sensor data (S19) and again determines whether or not an ACK has been received (S16).

[0064] According to the process described above, if an ACK is not received after transmitting sensor data, the number of possible retransmissions n is calculated and the sensor data is retransmitted. This enables dynamic adjustment, such as increasing the upper limit of the number of retransmissions as much as possible, thereby improving communication reliability and reducing data loss.

[0065] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made by those skilled in the art.

[0066] In the above embodiment, the determination of the number of retransmissions of data in two-way communication has been described, but the present invention is not limited to this, and a similar method may also be applied to determining the number of consecutive transmissions of data in protocols that do not send ACK responses or in one-way communication. Repeated transmission is a method of reducing the packet error rate by concatenating the same data in one packet and transmitting it.

[0067] In the above embodiment, the number of retransmissions of transmission data is variable based on the amount of data that can be transmitted within the permissible transmission time. However, this is not limiting, and the MCS index applied to the transmission data may be variable.

[0068] Representative embodiments of the present invention will be listed below.

[0069] (1) a wireless communication unit that performs wireless LAN communication; an acquisition unit that acquires statistical data including an MCS (Modulation and Coding Scheme) index and an amount of transmission data previously transmitted by the wireless communication unit; an estimation unit that estimates an amount of data that can be transmitted within an allowable transmission time or an allowable number of times that transmission data can be transmitted based on the statistical data; A wireless communication device comprising:

[0070] (2) the estimation unit estimates the amount of transmittable data that can be transmitted within the remaining time of the permissible transmission time or the number of times that the data can be transmitted; (1) A wireless communication device.

[0071] (3) a determination unit that determines the number of consecutive transmissions or the number of retransmissions of the transmission data based on the amount of transmittable data or the number of times of transmission; A wireless communication device according to (1) or (2).

[0072] (4) the estimation unit estimates the amount of transmittable data or the number of transmittable times that can be transmitted within a remaining time after transmission of the transmission data within the permissible transmission time; a determination unit that determines the number of retransmissions of the transmission data based on the transmittable data amount or the transmittable number of times; A wireless communication device according to any one of (1) to (3).

[0073] (5) The wireless communication unit performs 802.11ah wireless LAN communication. A wireless communication device according to any one of (1) to (4).

[0074] (6) Further comprising a sensor; the wireless communication unit periodically transmits sensor data detected by the sensor to a higher-level communication device; A wireless communication device according to any one of (1) to (5).

[0075] (7) A determination unit that determines the MCS index of the transmission data based on the transmittable data amount or the transmittable number of times. A wireless communication device according to any one of (1) to (6).

[0076] (8) Acquire statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication; Based on the statistical data, an amount of data that can be transmitted within the permissible transmission time or an allowable number of times that the transmission data can be transmitted is estimated. method.

[0077] (9) Acquiring statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication; and estimating the amount of data that can be transmitted within the permissible transmission time or the number of times that the transmission data can be transmitted based on the statistical data; A program that causes a computer to execute the following. [Explanation of symbols]

[0078] REFERENCE SIGNS LIST 1 access point, 2A, 2B relay devices, 3 sensor terminal, 4 management server, 10 control unit, 11 wireless communication unit, 12 wired communication unit, 20 control unit, 21 wireless communication unit, 30 control unit, 31 wireless communication unit, 33 sensor, 41 transmission processing unit, 42 statistical data acquisition unit, 43 transmittable amount estimation unit, 44 retransmission number determination unit, 49 statistical data storage unit, 100 wireless communication system

Claims

1. a wireless communication unit that executes wireless LAN communication; an acquisition unit that acquires statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by the wireless communication unit; an estimation unit that estimates an amount of data that can be transmitted within an allowable transmission time or an allowable number of times that transmission data can be transmitted based on the statistical data; A wireless communication device comprising:

2. the estimation unit estimates the amount of transmittable data that can be transmitted within the remaining time of the permissible transmission time or the number of times that the data can be transmitted; The wireless communication device according to claim 1 .

3. a determination unit that determines the number of consecutive transmissions or the number of retransmissions of the transmission data based on the amount of transmittable data or the number of times of transmission; The wireless communication device according to claim 1 .

4. the estimation unit estimates the amount of transmittable data or the number of transmittable times that can be transmitted within a remaining time after transmission of the transmission data within the permissible transmission time; a determination unit that determines the number of retransmissions of the transmission data based on the transmittable data amount or the transmittable number of times; The wireless communication device according to claim 1 .

5. The wireless communication unit performs 802.11ah wireless LAN communication. The wireless communication device according to claim 1 .

6. Further comprising a sensor; the wireless communication unit periodically transmits sensor data detected by the sensor to a higher-level communication device; The wireless communication device of claim 1 .

7. a determination unit that determines the MCS index of the transmission data based on the transmittable data amount or the transmittable number of times; The wireless communication device according to claim 1 .

8. Acquire statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication; Based on the statistical data, an amount of data that can be transmitted within the permissible transmission time or an allowable number of times that the transmission data can be transmitted is estimated. method.

9. Acquiring statistical data including an MCS (Modulation and Coding Scheme) index and a transmission data amount of transmission data previously transmitted by a wireless communication unit that performs wireless LAN communication; and estimating the amount of data that can be transmitted within the permissible transmission time or the number of times that the transmission data can be transmitted based on the statistical data; A program that causes a computer to execute the following.

Images