Wireless communication device and wireless communication method

Abstract

A wireless communication device according to one embodiment is characterized by comprising: a determination unit that determines whether a transmission frame is a wireless communication frame that requires frame exchange to establish communication; and a control unit that controls the switching of a wireless communication module that transmits transmission frames such that transmission frames, which are determined by the determination unit as wireless communication frames requiring frame exchange, are transmitted on a channel that has a limit on a total transmission time rate, and transmission frames, which are determined by the determination unit not to be the wireless communication frames requiring frame exchange, are transmitted on a channel that does not have a limit on a total transmission time rate.

Description

[Technical Field]

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

[0002] With the development of IoT (Internet of Things) wireless communications, there is a need to transmit not only sensor data but also image data and large volumes of data over wide wireless areas. For example, the 920 MHz band is being broadened and transmission capacity is being expanded through revisions to domestic laws and regulations.

[0003] However, the 920 MHz band has a total transmission time rate (a limit on the total transmission time per hour) of 10%, which means that the amount of data that a single terminal can transmit can be significantly less than the actual performance of the radio.

[0004] However, the limit on the total transmission time rate is a regulation for the shared band between active tags (wireless communication terminals such as sensor communication systems that transmit and receive by sensing the carrier before transmitting). There is no limit on the total transmission time rate for the priority band of passive tags (wireless communication terminals of electronic tag systems such as RFID that do not transmit radio waves themselves but return a response to transmitted radio waves). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] IEEE Standard for Information Technology-Telecommunications and Information Exchange between Systems Local and Metropolitan Area Networks- Specific Requirements, Part 11: Wireless LAN Medium Access Control(MAC) and Physical Layer (PHY) Specifications, IEEE Computer Society, Developed by the LAN / MAN Standards Committee, IEEE Std 802.11-2020 (Revision of IEEE Std 802.11-2016), Approved 3 December 2020, IEEE SA Standards Board [Non-patent document 2] "920MHz-BAND TELEMETER, TELECONTROL AND DATA TRANSMISSION RADIO EQUIPMENT", ARIB STANDARD, ARIB STD-T108 Version 1.4, Established February 14, 2012, Revised April 23, 2021, Association of Radio Industries and Businesses Summary of the Invention [Problem to be solved by the invention]

[0006] Although there is no limit on the total transmission time rate for the passive tag priority band, the carrier sense time before transmission is specified to be 5 msec or more, which is significantly longer than the carrier sense time (128 μsec or more) for the active tag shared band.

[0007] Furthermore, the passive tag priority band requires a 50 msec pause after the radio wave is emitted (the time to stop transmission of anything other than response signals such as ACK) (see Non-Patent Document 2). However, once a carrier sense of 5 msec or more is performed in the passive tag priority band, there is no pause and the carrier sense time is 128 μsec, as long as it is within 4 seconds of the initial radio wave emission.

[0008] Furthermore, in the passive tag priority band, when single frames such as beacon frames are periodically generated and transmission is attempted, the waiting time of surrounding terminals becomes long even if transmission is attempted all at once.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication device and a wireless communication method that can maximize transmission capacity within a predetermined range while also using channels with limited total transmission time rates. [Means for solving the problem]

[0010] A wireless communication device according to one embodiment of the present invention is a wireless communication device having a plurality of wireless communication modules that each perform wireless communication using a different channel, and is characterized by having a judgment unit that judges whether a transmission frame is a wireless communication frame that requires frame exchange to establish communication, and a control unit that controls the wireless communication module that transmits the transmission frame to switch so that a transmission frame that the judgment unit judges to be a wireless communication frame that requires frame exchange is transmitted on a channel with a limit on the total transmission time rate, and a transmission frame that the judgment unit judges not to be a wireless communication frame that requires frame exchange is transmitted on a channel without a limit on the total transmission time rate.

[0011] Furthermore, a wireless communication method according to one embodiment of the present invention is a wireless communication method performed by a wireless communication device having a plurality of wireless communication modules that each perform wireless communication using a different channel, and is characterized in that it includes a determination step of determining whether a transmission frame is a wireless communication frame that requires frame exchange to establish communication, and a control step of controlling the wireless communication module that transmits the transmission frame to switch so that a transmission frame determined to be a wireless communication frame that requires frame exchange is transmitted on a channel with a limit on the total transmission time rate, and a transmission frame determined not to be a wireless communication frame that requires frame exchange is transmitted on a channel without a limit on the total transmission time rate. [Effects of the Invention]

[0012] According to the present invention, it is possible to maximize the transmission capacity within a predetermined range while also using channels with a limited total transmission time rate. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates an example of the configuration of a wireless communication device according to an embodiment. [Figure 2] FIG. 10 is a diagram showing combinations of parameters for transmission time restrictions in each frequency band of the 920 MHz band. [Figure 3] FIG. 1 is a diagram showing channels and center frequencies of a passive tag priority band in the 920 MHz band. [Figure 4] FIG. 2 is a functional block diagram illustrating functions of a wireless communication device according to an embodiment. [Figure 5] 10 is a diagram illustrating timings at which a wireless communication device according to an embodiment transmits a transmission frame in a passive tag priority band. [Figure 6] FIG. 10 is a diagram showing transmission timing when multiple wireless communication devices interrupt even within the transmission time limit. [Figure 7] FIG. 1 illustrates an example of transmission of uplink and downlink traffic using multiple frequency channels. [Figure 8]10 is a flowchart illustrating a process performed by a wireless communication device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] A wireless communication device according to an embodiment will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a wireless communication device 1 according to an embodiment. As shown in Fig. 1, the wireless communication device 1 according to an embodiment includes, for example, a memory 10, a drive 11, a timer 12, a user interface 13, a wired communication module 14, a first wireless communication module 15-1, a second wireless communication module 15-2, and a control circuit 16, which are connected via a bus 17.

[0015] The memory 10 is a storage device that stores, for example, a control program 100 and management information 102. The drive 11 reads and writes data from and to a storage medium 110. The timer 12 measures the time when the wireless communication device 1 performs control. The user interface 13 is an input / output device that includes, for example, a keyboard and a display.

[0016] The wired communication module 14 is a module that performs wired communication with other devices. The first wireless communication module 15-1 and the second wireless communication module 15-2 each have a different NIC, and each perform wireless communication with other devices using a different channel.

[0017] The first wireless communication module 15-1 performs wireless communication using, for example, a passive tag priority band (see FIG. 2). The second wireless communication module 15-2 performs wireless communication using, for example, an active tag shared band (see FIG. 2). The number of wireless communication modules included in the wireless communication device 1 is not limited to two.

[0018] The control circuit 16 includes a CPU 160 and controls each component of the wireless communication device 1. For example, the control circuit 16 performs control using the time measured by the timer 12.

[0019] Figure 2 shows the combination of parameters for transmission time limits in each frequency band in the 920 MHz band. Figure 3 shows the channels and center frequencies of the passive tag priority band in the 920 MHz band. (A) in Figure 2 shows the parameters of the passive tag priority band. (B) in Figure 2 shows the parameters of the active tag shared band.

[0020] The passive tag priority band is a channel with no limit on the total transmission time rate. In the passive tag priority band, the carrier sense time is specified to be long so that the passive tag operation is not hindered by the transmission of the active tag, and a pause time is provided.

[0021] Specifically, the passive tag priority band is stipulated to have a carrier sense time of 5 msec or more before transmission, and a pause time of 50 msec or more after the radio wave is emitted during which transmissions other than response signals are stopped. Note that once a carrier sense of 5 msec or more is performed, the passive tag priority band does not require a pause time as long as it is within 4 seconds of the initial radio wave emission, and the carrier sense time is also stipulated to be 128 μsec.

[0022] In other words, the passive tag priority band is free from these restrictions for 4 seconds after the radio wave is emitted after a carrier sense of 5 msec or more, allowing for efficient transmission.

[0023] The active tag shared band is a channel with a limit on the total transmission time rate. Specifically, the active tag shared band has a limit of 10% or less, and the carrier sense time before transmission is set to 128 μsec. In other words, the active tag priority band has a limit of 360 seconds per hour for the total transmission time, which can make large-volume communication difficult.

[0024] 4 is a functional block diagram illustrating functions of the wireless communication device 1 according to an embodiment. As shown in FIG. 4, the wireless communication device 1 includes a determination unit 20 and a control unit 22, for example.

[0025] The determination unit 20 determines whether or not a transmission frame transmitted by the wireless communication device 1 is a wireless communication frame that requires frame exchange to establish communication, and outputs the determination result to the control unit 22.

[0026] The control unit 22 controls to switch between the first wireless communication module 15-1 and the second wireless communication module 15-2 that transmits the transmission frame so that a transmission frame that the determination unit 20 determines to be a wireless communication frame requiring frame exchange is transmitted on a channel with a limit on the total transmission time rate, and a transmission frame that the determination unit 20 determines not to be a wireless communication frame requiring frame exchange is transmitted on a channel with no limit on the total transmission time rate. Furthermore, the control unit 22 controls to perform burst transmission on a channel with no limit on the total transmission time rate.

[0027] 5 is a diagram showing the timing at which the wireless communication device 1 according to an embodiment transmits a transmission frame in the passive tag priority band. IEEE 802.11ah is one of the wireless communication standards used in the sub-1 GHz band. In IEEE 802.11ah, the time length of a wireless communication frame is 28 msec.

[0028] Therefore, even if the transmission time limit is 4 seconds or less, if there are multiple wireless communication devices and traffic, the delay time for the traffic of each wireless communication device may be long if there are many of them.In addition, between data frame communications such as TCP ACK, necessary uplink and downlink communications are also transmitted alternately.

[0029] Figure 6 shows the transmission timing when multiple wireless communication devices interrupt even within the transmission time limit. As shown in Figure 6, if 5 msec or more is required for carrier sensing before transmission, delays will increase significantly. On the other hand, in the active tag shared band, which has a limit on the total transmission time rate, sufficient communication capacity cannot be obtained.

[0030] Therefore, the wireless communication device 1 transmits only specific wireless communication devices or traffic in the passive tag priority band, and transmits other TCP layer response signals and management frames in the active tag band. For example, the wireless communication device 1 transmits the same TCP frame using different channels over multiple NICs using multipath TCP or the like.

[0031] Furthermore, when the traffic is asymmetric between the uplink and downlink (video transmission or large-volume data transmission), the wireless communication device 1 can transmit without being subject to restrictions on the total transmission time rate by also using the passive tag priority band rather than using only the active tag shared band.

[0032] 7 is a diagram showing an example of uplink and downlink traffic transmission using multiple frequency channels. The wireless communication device 1 performs burst transmission in the passive tag priority band for transmitting data frames that require a large transmission capacity. The wireless communication device 1 also uses the active tag shared band, which has a short pause time before transmission and a short carrier sense time, for other frames of the TCP protocol required for data frame communication.

[0033] In addition, since wireless communication device 1 cannot transmit L2 layer responses (ACK frames) using the passive tag priority band, it transmits data using the active tag shared band with a policy setting of "no ACK," and determines whether to retransmit at the application level using TCP ACK.

[0034] Furthermore, the wireless communication device 1 refrains from using the passive tag priority band for beacon frames that need to be transmitted periodically, and instead sets a longer "Max Idle Period" so that the connection will not be cut off even if a beacon frame does not arrive for a certain period of time using the active tag shared band.The wireless communication device 1 also uses the active tag shared band for other communications that do not require the use of the passive tag priority band.

[0035] 8 is a flowchart illustrating a process performed by the wireless communication device 1 according to an embodiment. As shown in FIG. 8, in the wireless communication device 1, for example, the determination unit 20 determines whether or not a transmission frame is a TCP layer data frame (S100). If the determination unit 20 determines that the transmission frame is a TCP layer data frame (S100: Yes), the wireless communication device 1 proceeds to the process of S102, and if the determination unit 20 determines that the transmission frame is not a TCP layer data frame (S100: No), the wireless communication device 1 proceeds to the process of S104.

[0036] In step 102 (S102), the wireless communication device 1 performs wireless communication using the passive tag priority band.

[0037] In step 104 (S104), the wireless communication device 1 performs wireless communication using the active tag shared band.

[0038] In this way, the wireless communication device 1 of one embodiment switches the wireless communication module that transmits the transmission frame so that, for a transmission frame that the determination unit 20 determines to be a wireless communication frame that requires frame switching, the transmission frame is transmitted on a channel with a limit on the total transmission time rate, and, for a transmission frame that the determination unit 20 determines not to be a wireless communication frame that requires frame switching, the transmission frame is transmitted on a channel with no limit on the total transmission time rate.Therefore, it is possible to maximize the transmission capacity within a predetermined range while also using channels with a limit on the total transmission time rate.

[0039] In addition, each function of the wireless communication device 1 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0040] For example, the wireless communication device 1 according to the present invention can be realized using a computer and a program, and the program can be recorded on a storage medium or provided via a network. [Explanation of symbols]

[0041] 1 wireless communication device, 10 memory, 12 timer, 13 user interface, 14 wired communication module, 15-1 first wireless communication module, 15-2 second wireless communication module, 16 control circuit, 17 bus, 20 determination unit, 22 control unit, 100 control program, 102 management information, 110 storage medium, 160 CPU

Claims

1. A wireless communication device includes a plurality of wireless communication modules that perform wireless communication using different channels, a determination unit that determines whether or not a transmission frame is a wireless communication frame that requires frame exchange to establish communication; a control unit that controls switching of the wireless communication module that transmits a transmission frame so that a transmission frame that the determination unit determines to be a wireless communication frame that requires frame exchange is transmitted on a channel that has a limit on a total transmission time rate, and a transmission frame that the determination unit determines not to be a wireless communication frame that requires frame exchange is transmitted on a channel that does not have a limit on a total transmission time rate; A wireless communication device comprising:

2. The channel with a limit on the total transmission time rate is A channel using the active tag shared band, The channel with no restriction on the total transmission time rate is The channel must use the passive tag priority band.

2. The wireless communication device according to claim 1,

3. The active tag shared band is The total transmission time rate is specified to be 10% or less, and the carrier sense time before transmission is specified to be 128 μsec. The passive tag priority band is: The carrier sense time before transmission is specified to be 5 msec or more, the pause time for stopping transmission other than the response signal is specified to be 50 msec or more from the emission of radio waves, and once a carrier sense of 5 msec or more has been performed, the pause time is not required as long as it is within 4 seconds from the first emission of radio waves, and the carrier sense time is also specified to be 128 μsec.

3. The wireless communication device according to claim 2, wherein:

4. The control unit In channels with no limit on the total transmission time rate, control is performed to perform burst transmission.

4. The wireless communication device according to claim 1, wherein:

5. A wireless communication method performed by a wireless communication device having a plurality of wireless communication modules that perform wireless communication using different channels, a determining step of determining whether the transmission frame is a wireless communication frame that requires frame exchange to establish communication; a control step of controlling the wireless communication module transmitting the transmission frame to switch the wireless communication module so that the transmission frame determined to be a wireless communication frame requiring frame exchange is transmitted on a channel having a limit on the total transmission time rate, and the transmission frame determined not to be a wireless communication frame requiring frame exchange is transmitted on a channel having no limit on the total transmission time rate; A wireless communication method comprising:

6. The channel with a limit on the total transmission time rate is A channel using the active tag shared band, The channel with no restriction on the total transmission time rate is The channel must use the passive tag priority band.

6. The wireless communication method according to claim 5,

7. The active tag shared band is The total transmission time rate is specified to be 10% or less, and the carrier sense time before transmission is specified to be 128 μsec. The passive tag priority band is: The carrier sense time before transmission is specified to be 5 msec or more, the pause time for stopping transmission other than the response signal is specified to be 50 msec or more from the emission of radio waves, and once a carrier sense of 5 msec or more has been performed, the pause time is not required as long as it is within 4 seconds from the first emission of radio waves, and the carrier sense time is also specified to be 128 μsec.

7. The wireless communication method according to claim 6, wherein:

8. The control step includes: In channels with no limit on the total transmission time rate, control is performed to perform burst transmission. The wireless communication method according to any one of claims 5 to 7,

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