Wireless communication device and wireless communication method

Abstract

To provide a radio communication device and a radio communication method that can prevent communication contents from being intercepted.SOLUTION: A radio communication device 10 includes: a generation unit 11 that generates a first unique word based on operation time information of the radio communication device 10 before communication with a radio communication device 20 starts, and generates an i-th unique word based on a (i-1)th unique word (i is an integer of two or more) for each radio frame when communication is started; and a transmission unit 12 that transmits a first radio frame including the first unique word and an i-th radio frame including the i-th unique word to the radio communication device 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In digital wireless communication between a wireless communication device on the transmitting side and a wireless communication device on the receiving side, the wireless frame to be transmitted and received contains a frame synchronization code indicating a code string for frame synchronization so that the start timing of the wireless frame to be transmitted and received can be detected. The frame synchronization code is also called a unique word.

[0003] Here, if a third party other than the user of the receiving wireless communication device detects the unique word used in communication, the data included in the wireless frame can also be detected, and there is a risk that the communication content will be intercepted. Therefore, a technique for switching unique words is known as a technique for preventing a third party from intercepting the communication content (for example, Patent Document 1). Patent Document 1 discloses that a microphone, which is a transmitting wireless communication device, switches unique words depending on the communication mode.

[0004] However, in Patent Document 1, if the communication mode is not changed from the start to the end of communication, the same unique word is added to the transmitted wireless frame. Therefore, if a third party knows the communication mode, there is a risk that they will detect the unique word added to the wireless frame, which may result in the communication content being intercepted. Therefore, technologies to further prevent third parties from intercepting the communication content are being considered (for example, Patent Documents 2 to 4).

[0005] Patent Document 2 discloses that a wireless communication device on the transmitting side holds multiple unique word patterns, and adds to each wireless frame a unique word generated according to a unique word pattern selected from the multiple unique word patterns. Patent Document 3 discloses that a transmitting unit in a communication system adds to each wireless frame a unique word generated based on a reference unique word pattern and multiple special unique word patterns. Patent Document 4 discloses that a transmitting unit in a communication system generates a first unique word based on a reference unique word pattern and a special unique word pattern. Patent Document 4 also discloses that a pseudo-random pattern based on a special unique word pattern is generated for each wireless frame, and second and subsequent unique words are generated based on the generated pseudo-random pattern and the reference unique word pattern. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-124847 A [Patent Document 2] Japanese Patent Application Publication No. 01-077234 [Patent Document 3] Japanese Patent Application Publication No. 08-195739 [Patent Document 4] JP 2002-016589 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the techniques disclosed in Patent Documents 2 to 4, the unique word added to a wireless frame is changed for each wireless frame. The technique disclosed in Patent Document 2 uses a plurality of unique word patterns, but since the number of unique word patterns is finite, a third party may be able to know the unique word pattern used in the communication by continuously monitoring the communication contents. When the techniques disclosed in Patent Documents 3 and 4 are used, at least the unique word generated initially is based on a fixed reference unique word pattern and a special unique word pattern that are independent of the communication, so the unique word used for each communication is fixed. Therefore, even when the techniques disclosed in Patent Documents 3 and 4 are used, a third party may be able to know the unique word used in the communication by continuously monitoring the communication contents. Therefore, even when the techniques disclosed in Patent Documents 2 to 4 are used, a third party may be able to eavesdrop on the communication contents.

[0008] An object of the present disclosure is to solve the above-mentioned problems, and to provide a wireless communication device and a wireless communication method that can prevent communication contents from being intercepted. [Means for solving the problem]

[0009] A wireless communication device according to a first aspect of the present disclosure includes: 1. A wireless communication device, comprising: a generating unit that generates a first unique word based on operation time information of the wireless communication device before communication with another wireless communication device is started, and generates an i-th unique word based on an (i-1)-th unique word (i: an integer equal to or greater than 2) for each wireless frame when the communication is started; a transmitter configured to transmit a first radio frame including the first unique word and the i-th radio frame including the i-th unique word to the other radio communication device.

[0010] A wireless communication device according to a second aspect of the present disclosure includes: 1. A wireless communication device, comprising: a generation unit that generates a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device, the second operating time information corresponding to first operating time information used by the other wireless communication device to generate a first transmission unique word, before communication with the other wireless communication device is started; a receiving unit that receives a radio frame including the first transmission unique word based on the first reception unique word, the generation unit generates, when the communication is started, for each wireless frame, an i-th reception unique word corresponding to an i-th transmission unique word generated by the other wireless communication device, based on an (i-1)-th reception unique word (i: an integer equal to or greater than 2); The receiver receives a radio frame including the ith transmission unique word based on the ith reception unique word.

[0011] A wireless communication method according to a first aspect of the present disclosure includes: 1. A wireless communication method performed by a wireless communication device, comprising: generating a first unique word based on operation time information of the wireless communication device before communication with another wireless communication device is started; When the communication is started, a first wireless frame including the first unique word is transmitted to the other wireless communication device; generating an ith unique word for each radio frame based on an (i-1)th unique word (i: an integer equal to or greater than 2); The i-th wireless frame including the i-th unique word is transmitted to the other wireless communication device.

[0012] A wireless communication method according to a second aspect of the present disclosure includes: 1. A wireless communication method performed by a wireless communication device, comprising: before communication with another wireless communication device is started, generating a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device, the second operating time information corresponding to first operating time information used by the other wireless communication device to generate a first transmission unique word; receiving a wireless frame including the first transmission unique word based on the first reception unique word when the communication is started; generating an ith reception unique word corresponding to an ith transmission unique word generated by the other wireless communication device, based on an (i-1)th reception unique word (i: an integer equal to or greater than 2) for each wireless frame; A radio frame including the i-th transmission unique word is received based on the i-th reception unique word. Effect of the Invention

[0013] According to the present disclosure, it is possible to provide a wireless communication device and a wireless communication method capable of preventing communication content from being intercepted. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to a first embodiment. [Diagram 2] 4 is a sequence diagram showing an example of operation of the wireless communication system according to the first embodiment. FIG. [Diagram 3] FIG. 11 is a diagram illustrating a configuration example of a wireless communication system according to a second embodiment. [Figure 4] 11 is a diagram for explaining the flow of UW update in a wireless communication device according to a second embodiment. FIG. [Diagram 5] FIG. 11 is a diagram illustrating a configuration example of a random number reference sequence generating circuit according to a second embodiment. [Figure 6] FIG. 11 is a diagram for explaining an example of a random number table according to the second embodiment; [Figure 7] FIG. 11 is a diagram illustrating a configuration example of a conversion sequence generating circuit according to a second embodiment. [Figure 8] FIG. 11 is a diagram illustrating an example of the operation of the wireless communication system according to the second embodiment. [Figure 9] FIG. 11 is a diagram illustrating an example of the operation of the wireless communication system according to the second embodiment. [Figure 10] FIG. 11 is a diagram illustrating an example of the operation of the wireless communication system according to the second embodiment. [Figure 11] FIG. 11 is a diagram for explaining an outline of the operation of a wireless communication device in the third embodiment. [Figure 12] FIG. 11 is a diagram illustrating a configuration example of a wireless communication system according to a third embodiment. [Figure 13] FIG. 11 is a diagram illustrating an example of the operation of a wireless communication system according to a third embodiment. [Figure 14] FIG. 2 is a block diagram illustrating a hardware configuration of a computer (information processing device) capable of implementing a wireless device according to each embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the following description and drawings are omitted and simplified as appropriate for clarity of explanation. In addition, in each of the following drawings, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0016] (Embodiment 1) A configuration example of a wireless communication system 100 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a configuration example of a wireless communication system according to the first embodiment. The wireless communication system 100 includes a wireless communication device 10 and a wireless communication device 20. The wireless communication devices 10 and 20 perform digital wireless communication with the wireless communication devices 20 and 10, respectively, via wireless lines.

[0017] The wireless communication device 10 operates as a wireless communication device on the transmitting side, and the wireless communication device 20 operates as a wireless communication device on the receiving side. Note that the wireless communication device 10 can also operate as a wireless communication device on the receiving side, and the wireless communication device 20 can also operate as a wireless communication device on the transmitting side. Therefore, the wireless communication device 10 may include a receiving unit of the wireless communication device 20, which will be described later, and the wireless communication device 20 may include a transmitting unit of the wireless communication device 10, which will be described later. In the following description, the wireless communication device on the transmitting side may be described as a transmitting station, and the wireless communication device on the receiving side may be described as a receiving station.

[0018] The wireless communication device 10 generates a unique word, which is a frame synchronization code, for each wireless frame, and transmits to the wireless communication device 20 the wireless frame including the generated unique word. The wireless communication device 20 generates a unique word for each wireless frame transmitted from the wireless communication device 10, and receives the wireless frames based on the generated unique word.

[0019] The wireless communication device 10 includes a generation unit 11 and a transmission unit 12 . Before communication with the wireless communication device 20 is started, the generation unit 11 generates a first transmission unique word based on the first operation time information of the wireless communication device 10. The first transmission unique word is a unique word that is added to a first wireless frame indicating the first wireless frame transmitted to the wireless communication device 20 immediately after communication with the wireless communication device 20 is started. The first operation time information is operation time information used for the operation of the wireless communication device 10. The first operation time information may be, for example, time information that is determined by calculating the elapsed time from a reference time using an operation clock.

[0020] As will be described later, the wireless communication device 20 also generates a unique word for detecting a wireless frame received from the wireless communication device 10. Therefore, in this disclosure, in order to distinguish between a unique word generated by the wireless communication device 10 on the transmitting side and a unique word generated by the wireless communication device 20 on the receiving side, the unique word generated by the wireless communication device 10 is described as a transmission unique word. Also, the unique word generated by the wireless communication device 20 is described as a reception unique word. The transmission unique word is a unique word generated by the wireless communication device on the transmitting side and is a unique word added to a wireless frame transmitted by the wireless communication device on the transmitting side. Also, the reception unique word is a unique word generated by the wireless communication device on the receiving side and is a unique word used to detect a wireless frame received by the wireless communication device on the receiving side and to receive the detected wireless frame.

[0021] When communication with wireless communication device 20 is started, generation unit 11 generates an ith transmission unique word for each wireless frame based on the (i-1)th transmission unique word (i: an integer equal to or greater than 2). The ith transmission unique word is a transmission unique word that is added to an ith wireless frame indicating the wireless frame transmitted for the ith time after communication with wireless communication device 20 is started. Generation unit 11 updates the transmission unique word for each wireless frame by generating the ith transmission unique word based on the (i-1)th transmission unique word.

[0022] When communication with the wireless communication device 20 is started, the transmitter 12 transmits a first wireless frame including a first transmission unique word to the wireless communication device 20. In addition, the transmitter 12 transmits an ith wireless frame including an ith transmission unique word to the wireless communication device 20.

[0023] The wireless communication device 20 includes a generation unit 21 and a reception unit 22 . Before communication with the wireless communication device 10 is started, the generation unit 21 generates a first reception unique word corresponding to the first transmission unique word based on second operation time information, which is second time information of the wireless communication device 20 and corresponds to the first operation time information. The first reception unique word is a reception unique word used to detect the first transmission unique word included in the first wireless frame and to receive the first wireless frame. The second operation time information is operation time information used for the operation of the wireless communication device 20. The second operation time information may be, for example, time information determined by calculating the elapsed time from a reference time using an operation clock.

[0024] Furthermore, when communication with wireless communication device 10 is started, generation unit 21 generates, for each wireless frame, an ith reception unique word corresponding to the ith transmission unique word generated by wireless communication device 10, based on the (i-1)th reception unique word. The ith reception unique word is a reception unique word that is used to detect the ith transmission unique word added to the ith wireless frame indicating the wireless frame transmitted i-th after communication with wireless communication device 10 is started, and to receive the ith wireless frame. The generation unit 21 updates the reception unique word for each wireless frame by generating the ith reception unique word based on the (i-1)th reception unique word.

[0025] When communication with the wireless communication device 10 is started, the receiving unit 22 receives a wireless frame including a first transmission unique word based on the first reception unique word. The receiving unit 22 receives a wireless frame including the i-th transmission unique word based on the i-th reception unique word.

[0026] Next, an operation example of the wireless communication system 100 will be described with reference to Fig. 2. Fig. 2 is a sequence diagram showing an operation example of the wireless communication system according to the first embodiment. Before communication with the wireless communication device 20 is started, the generation unit 11 generates a first transmission unique word based on the first operation time information of the wireless communication device 10 (step S1-1).

[0027] Before communication with the wireless communication device 10 is started, the generation unit 21 generates a first reception unique word corresponding to the first transmission unique word based on the second operation time information corresponding to the first operation time information (step S1-2). Note that since it is only necessary for the generation unit 21 to generate a first reception unique word corresponding to the first transmission unique word, step S1-2 may or may not be performed simultaneously with step S1-1.

[0028] When communication with the wireless communication device 20 is started, the transmitter 12 transmits a first wireless frame including a first transmission unique word to the wireless communication device 20 (step S1-3). When communication with the wireless communication device 10 is started, the receiver 22 receives a first wireless frame including a first transmission unique word based on the first reception unique word (step S1-4).

[0029] When communication with the wireless communication device 20 is started, the generation unit 11 generates a second transmission unique word for a second wireless frame based on the first transmission unique word (step S2-1).

[0030] When communication with the wireless communication device 10 is started, the generation unit 21 generates a second reception unique word corresponding to the second transmission unique word based on the first reception unique word (step S2-2). Note that since it is only necessary for the generation unit 21 to generate a second reception unique word corresponding to the second transmission unique word, step S2-2 may or may not be performed simultaneously with step S2-1.

[0031] The transmitter 12 transmits the second wireless frame including the second transmission unique word to the wireless communication device 20 (step S2-3). The receiver 22 receives a second wireless frame including a second transmission unique word based on the second reception unique word (step S2-4). The wireless communication devices 10 and 20 repeatedly execute steps S2-1 to S2-4 for each wireless frame until the communication is terminated.

[0032] As described above, the wireless communication device 10 generates the first transmission unique word using the first operation time information of the wireless communication device 10, and therefore can generate a different first transmission unique word each time communication is performed with the wireless communication device 20. Furthermore, the wireless communication device 10 updates the transmission unique word for each wireless frame, which can prevent a third party from intercepting the communication content. Therefore, even if a third party continuously monitors the communication between the wireless communication device 10 and the wireless communication device 20, the third party cannot know the transmission unique word used in the communication between the wireless communication device 10 and the wireless communication device 20. Therefore, the wireless communication device 10 according to the first embodiment can prevent the communication content from being intercepted.

[0033] Furthermore, the wireless communication device 20 generates a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device 20, which corresponds to the first operating time information. The wireless communication device 20 generates an ith reception unique word corresponding to the ith transmission unique word based on the first reception unique word. Therefore, even if the wireless communication device 10 generates a different transmission unique word for each wireless frame and for each communication, it is possible to receive wireless frames transmitted from the wireless communication device 10. In other words, the wireless communication system 100 including the wireless communication device 10 and the wireless communication device 20 can perform normal communication while preventing a third party from eavesdropping on the communication contents.

[0034] (Embodiment 2) Next, a description will be given of embodiment 2. Embodiment 2 is an embodiment in which embodiment 1 is made more specific. <Example of wireless communication system configuration> A configuration example of a wireless communication system 200 according to the second embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing a configuration example of a wireless communication system according to the second embodiment. The wireless communication system 200 includes a wireless communication device 30 and a wireless communication device 40.

[0035] The wireless communication device 30 corresponds to the wireless communication device 10 in the first embodiment. The wireless communication device 30 performs digital wireless communication with the wireless communication device 40 via a wireless line. The wireless communication device 30 operates as a transmitting station, which is a wireless communication device on the transmitting side. The wireless communication device 30 may also be capable of operating as a wireless communication device on the receiving side. Therefore, the wireless communication device 30 may include a receiving unit included in the wireless communication device 40. The wireless communication device 30 generates wireless frames to be transmitted to the wireless communication device 40, and generates a transmission UW (Unique word), which is a frame synchronization code, for each wireless frame. The wireless communication device 30 transmits the wireless frame including the generated transmission UW to the wireless communication device 40.

[0036] The wireless communication device 40 corresponds to the wireless communication device 20 in the first embodiment. The wireless communication device 40 operates as a receiving station, which is a wireless communication device on the receiving side. The wireless communication device 40 may also be capable of operating as a wireless communication device on the transmitting side. Therefore, the wireless communication device 40 may include a transmitting unit included in the wireless communication device 30. The wireless communication device 40 generates a reception UW for each wireless frame transmitted from the wireless communication device 30, and receives a wireless frame including the generated reception UW.

[0037] In this embodiment, it is assumed that the operation times of the wireless communication device 30 and the wireless communication device 40 are synchronized with an accuracy of a certain error or less. In other words, it is assumed that the error between the transmitting station operation time information indicating the operation time used by the wireless communication device 30 for the operation of the wireless communication device 30 and the receiving station operation time information indicating the operation time used by the wireless communication device 40 for the operation of the wireless communication device 40 is a certain value or less.

[0038] Here, before describing the details of the configuration example of the wireless communication devices 30 and 40, a description will be given of the timing of generating UWs and the UWs generated in the wireless communication devices 30 and 40. Fig. 4 is a diagram for explaining the flow of UW update in the wireless communication device according to the second embodiment.

[0039] The horizontal axis in Fig. 4 indicates time. The upper side of Fig. 4 shows the generation timing of UWs generated in wireless communication device 30, which is the transmitting station, and the generated UWs. The lower side of Fig. 4 shows the generation timing of UWs generated in wireless communication device 40, which is the receiving station, and the generated UWs.

[0040] In Fig. 4, UW(t)0 indicates a transmission UW generated based on the transmitting station operation time information when the operation time indicated by the transmitting station operation time information is time t. Also, for example, UW(t+2)2 indicates a transmission UW in which UW(t+2)0, which is a transmission UW generated based on the transmitting station operation time information when the operation time indicated by the transmitting station operation time information is time (t+2), has been updated twice. The above content also applies to the receiving UW.

[0041] In a standby state before communication starts, the wireless communication device 30 generates a transmission standby UW that can be used for the first transmission UW for the first wireless frame transmitted immediately after communication starts, based on the transmitting station operation time information. The wireless communication device 30 generates a transmission standby UW and updates the transmission standby UW at a predetermined periodic time. The predetermined periodic time may be one second or one minute.

[0042] 4, when the wireless communication device 30 generates a transmission standby UW at time t, the wireless communication device 30 generates UW(t)0 as a transmission standby UW based on the transmitting station operation time information corresponding to the time t. When the wireless communication device 30 generates a transmission standby UW at time (t+1), the wireless communication device 30 generates UW(t+1)0 as a transmission standby UW based on the transmitting station operation time information corresponding to the time (t+1). When the wireless communication device 30 generates a transmission standby UW at time (t+2), the wireless communication device 30 generates UW(t+2)0 as a transmission standby UW based on the transmitting station operation time information corresponding to the time (t+2).

[0043] In a communication state after the start of communication, the wireless communication device 30 generates an i-th transmission UW for an i-th wireless frame based on the (i-1)-th transmission UW for each wireless frame. Specifically, in the communication state, the wireless communication device 30 uses the transmission standby UW generated immediately before the start of communication as the first transmission UW, and updates the (i-1)-th transmission UW based on the first transmission UW for each wireless frame. The wireless communication device 30 generates an i-th transmission UW for an i-th wireless frame by updating the (i-1)-th transmission UW.

[0044] For example, when communication is started between time (t+2) and time (t+3), the wireless communication device 30 uses UW(t+2)0, which is the transmission standby UW immediately before the start of communication, as the first transmission UW and adds it to the first wireless frame 1_1, indicated by the thick dotted line. The wireless communication device 30 transmits the wireless frame 1_1 including the first transmission UW to the wireless communication device 40. For ease of explanation, information other than the UW and data is omitted in FIG. 4.

[0045] The wireless communication device 30 updates UW(t+2)0 based on UW(t+2)0, which is the first transmission UW, to generate UW(t+2)1, which is the second transmission UW to be added to the second wireless frame, and updates the transmission UW. The wireless communication device 30 adds the second transmission UW to the second wireless frame 1_2, which is indicated by a thick dotted line, and transmits the wireless frame 1_2 to the wireless communication device 40. The wireless communication device 30 thereafter similarly updates the i-th transmission UW to be added to the i-th wireless frame to UW(t+2), which is the (i-1)th transmission UW. i-2 and generates the i-th transmission UW to be added to the i-th wireless frame. The wireless communication device 30 transmits the i-th wireless frame including the i-th transmission UW to the wireless communication device 40.

[0046] In the standby state, the wireless communication device 40 generates a reception standby UW that can be used as a reception UW for receiving the first wireless frame transmitted immediately after the start of communication, based on the receiving station operation time information. The wireless communication device 40 generates the reception standby UW at the same timing as the wireless communication device 30 generates the transmission standby UW. The wireless communication device 40 generates the reception standby UW and updates the reception standby UW.

[0047] When the information used to generate the reception UW is the same as the information used to generate the transmission UW, the wireless communication device 40 is configured to be able to generate a reception UW that is identical to the transmission UW generated by the wireless communication device 30. In this embodiment, the receiving station operation time information is within a certain error range from the transmitting station operation time information, and the wireless communication device 40 generates a reception standby UW with the same periodic time and the same generation timing as the wireless communication device 30. Therefore, the wireless communication device 40 generates a reception standby UW that is identical to the transmission standby UW.

[0048] 4, when the wireless communication device 30 generates a transmission standby UW at time t, the wireless communication device 40 generates a reception standby UW, UW(t)0, which is the same as the transmission UW generated by the wireless communication device 30, based on the receiving station operation time information corresponding to the time t. When the wireless communication device 30 generates a transmission standby UW at time (t+1), the wireless communication device 40 generates a reception standby UW, UW(t+1)0, which is the same as the transmission UW generated by the wireless communication device 30, based on the receiving station operation time information corresponding to the time (t+1). When the wireless communication device 30 generates a transmission standby UW at time (t+2), the wireless communication device 40 generates a reception standby UW, UW(t+2)0, which is the same as the transmission UW generated by the wireless communication device 30, based on the receiving station operation time information corresponding to the time (t+2).

[0049] In a communication state, the wireless communication device 40 generates an i-th reception UW for receiving an i-th wireless frame based on an (i-1)-th reception UW for each wireless frame. Specifically, in a communication state, the wireless communication device 40 uses a reception standby UW generated immediately before the start of communication as the first reception UW, and generates an (i-1)-th reception UW based on the first reception UW for each wireless frame. The wireless communication device 40 generates an i-th reception UW for receiving an i-th wireless frame by updating the (i-1)-th reception UW. The wireless communication device 40 generates an i-th reception UW that is the same as the i-th transmission UW. The wireless communication device 40 detects a transmission UW that is the same as the generated reception UW, and receives a wireless frame including a transmission UW that is the same as the reception UW.

[0050] In FIG. 4, when communication is started, wireless communication device 40 uses UW(t+2)0, which is the UW waiting to be received immediately before communication is started, as the first received UW, detects UW(t+2)0, and receives the first wireless frame including UW(t+2)0. When wireless communication device 40 receives a wireless frame including UW(t+2)0, it updates UW(t+2)0, which is the first received UW, and generates UW(t+2)1 as the second received UW. Thereafter, wireless communication device 40 similarly updates UW(t+2), which is the (i-1)th received UW, when it receives the (i-1)th wireless frame. i-2 and generates the i-th reception UW for receiving the i-th wireless frame. The wireless communication device 40 detects the i-th transmission UW that is identical to the i-th reception UW, and receives the i-th wireless frame that includes the i-th transmission UW.

[0051] Thus, in the standby state, the wireless communication device 30 periodically generates a first transmission UW based on the transmitting station operation time information, thereby generating a different first transmission UW for each communication, and preventing a third party from intercepting the first wireless frame. When transitioning to the communication state, the wireless communication device 30 updates the first transmission UW, which is different for each communication, for each wireless frame, thereby generating a different transmission UW for each communication and for each wireless frame, and preventing a third party from intercepting the second and subsequent wireless frames.

[0052] Moreover, wireless communication device 40 is configured to generate a receiving UW that is identical to the transmitting UW generated by wireless communication device 30, and to be able to receive wireless frames normally even if wireless frames including different transmitting UWs are transmitted for each communication and for each wireless frame. Thus, in this embodiment, wireless communication device 40 realizes normal communication while preventing a third party from eavesdropping on wireless frames.

[0053] <Example of wireless communication device configuration> 3, a description will be given of an example configuration of the wireless communication device 30. The wireless communication device 30 includes a storage unit 31, a generating unit 32, and a transmitting unit .

[0054] The storage unit 31 stores transmitting station operation time information indicating operation time used for operation of the wireless communication device 30. The transmitting station operation time information may be determined based on a reference time and an operation clock used for operation of the wireless communication device 30, or the operation clock may calculate the elapsed time from the reference time and determine the transmitting station operation time information.

[0055] The transmitting station operation time information may be configured to include 26 bits, including 9 bits for forming a date (month and day) and 17 bits for forming a time (hour, minute, and second). The transmitting station operation time information may be configured, for example, with 4 bits indicating the month (January to December), 5 bits indicating the day (1st to 31st), 5 bits indicating the hour (0:00 to 23:00), 6 bits indicating the minute (0 minutes to 59 minutes), and 6 bits indicating the second (0 seconds to 59 seconds).

[0056] The generating unit 32 corresponds to the generating unit 11 in the first embodiment. Before communication with the wireless communication device 40 is started, the generating unit 32 generates a transmission standby UW based on the transmitting station operation time information. The generating unit 32 generates a transmission standby UW based on the transmitting station operation time information at a predetermined periodic time and periodically updates the transmission standby UW. The transmission standby UW is a transmission UW that can be used as the first transmission UW that is added to the first wireless frame transmitted immediately after the start of communication. That is, in a standby state before communication with the wireless communication device 40 is started, the generating unit 32 generates a transmission standby UW based on the transmitting station operation time information at a predetermined periodic time and updates the transmission standby UW.

[0057] When communication with the wireless communication device 40 is started, the generation unit 32 generates an i-th transmission UW for each wireless frame based on the (i-1)-th transmission UW to be added to the i-th wireless frame transmitted from the start of communication. When data is input to the wireless communication device 30 and the wireless communication device 30 transitions to a communication state, the generation unit 32 determines that communication with the wireless communication device 40 has started. When communication with the wireless communication device 40 is started, the generation unit 32 uses the transmission standby UW generated immediately before the start of communication as the first transmission UW, updates the first transmission UW (i-1) times for each wireless frame, and generates the i-th transmission UW. Since the transmission standby UW is used as the first transmission UW, it can also be said that the generation unit 32 updates the transmission standby UW generated immediately before the start of communication (i-1) times for each wireless frame to generate the i-th transmission UW.

[0058] The generation unit 32 includes a reference sequence output unit 321 , a random number output unit 322 , and a converted sequence output unit 323 . The reference sequence output unit 321 is configured to be able to output a random number reference sequence, which is a pseudo-random number sequence, and outputs the random number reference sequence to the random number output unit 322. In the standby state, the reference sequence output unit 321 outputs a random number reference sequence, which is a pseudo-random number sequence, based on transmitting station operation time information. In the following description, a random number reference sequence based on operation time information (transmitting station operation time information or receiving station operation time information) will be described as the first random number reference sequence. Also, a random number reference sequence based on the first random number reference sequence will be described as the second random number reference sequence, and a random number reference sequence based on the (i-1)th random number reference sequence will be described as the i-th random number reference sequence.

[0059] The reference sequence output unit 321 includes a random number reference sequence generation circuit 50 that outputs a random number reference sequence that is a pseudo-random number sequence, and uses the random number reference sequence generation circuit 50 to generate and output the random number reference sequence. Here, a configuration example of the random number reference sequence generating circuit 50 will be described with reference to Fig. 5. Fig. 5 is a diagram showing a configuration example of the random number reference sequence generating circuit according to the second embodiment.

[0060] The random number reference sequence generating circuit 50 includes a shift register 51, a feedback tap 53, AND circuits 55-1 to 55-N, and XOR (exclusive or) circuits 56-1 to 56-(N-1), where N is an integer of 2 or more. Shift register 51 includes taps 52-1 to 52-N. The number of taps included in shift register 51 corresponds to the number of bits constituting the transmitting station operation time information. For example, when the transmitting station operation time information is composed of 26 bits, N is 26, and shift register 51 includes taps 52-1 to 52-26.

[0061] The shift register 51 inputs each of the multiple bits constituting the transmitting station operation time information to each of the taps 52-1 to 52-N. For example, it is assumed that the transmitting station operation time information is composed of 26 bits, and the shift register 51 includes the taps 52-1 to 52-26. If the information indicating the month is composed of 4 bits, the shift register 51 inputs each of the 4 bits indicating the month to the taps 52-1 to 52-4. If the information indicating the day is composed of 5 bits, the shift register 51 inputs each of the 5 bits indicating the day to the taps 52-5 to 52-9. If the information indicating the hour is composed of 5 bits, the shift register 51 inputs each of the 5 bits indicating the hour to the taps 52-10 to 52-14. If the information indicating the minute is composed of 6 bits, the shift register 51 inputs each of the 6 bits indicating the minute to the taps 52-15 to 52-20. If the information indicating the second is composed of 6 bits, the shift register 51 inputs each of the 6 bits indicating the second to the taps 52-21 to 52-26. The shift register 51 may receive, in order from the lowest numbered tap, a bit indicating the second, a bit indicating the minute, a bit indicating the hour, a bit indicating the day, and a bit indicating the month.

[0062] A clock signal is input to the shift register 51, and the shift register 51 sequentially transmits the values ​​of each bit constituting the transmitting station operation time information input to the taps 52-1 to 52-N in synchronization with the clock signal. The clock signal is supplied by a clock possessed by the random number reference sequence generating circuit 50, and operates at a constant repetition frequency. The shift register 51 transmits (outputs) the value of the tap 52-m (m:1 to N-1) to the tap 52-(m+1) and the AND circuit 55-m by advancing the clock time of the clock possessed by the random number reference sequence generating circuit 50 by one. The shift register 51 also transmits (outputs) the value of the tap 52-N to the AND circuit 55-N by advancing the clock time of the clock by one. In other words, the shift register 51 sequentially shifts the shift register 51 by advancing the clock time by one. Moreover, the shift register 51 advances the clock time of the clock by one to output the values ​​of the taps 52-1 to 52-N to the reference sequence output unit 321. The shift register 51 advances the clock time by one to output the values ​​of each tap as values ​​P1 to PN constituting the random number reference sequence.

[0063] The feedback tap 53 specifies a tap, among the taps 52-1 to 52-N, whose tap value is fed back to the shift register 51. The feedback tap 53 is configured, for example, so that 0 or 1 is set for each of the taps 52-1 to 52-N. The feedback tap 53 specifies the tap to be fed back by inputting 1 to an AND circuit, among the AND circuits 55-1 to 55-N, corresponding to the tap whose tap value is fed back, and inputting 0 to an AND circuit, corresponding to the tap whose tap value is not fed back.

[0064] The AND circuits 55-1 to 55-N are provided corresponding to the taps 52-1 to 52-N of the shift register 51. The AND circuits 55-1 to 55-N respectively receive the values ​​output from the taps 52-1 to 52-N and the values ​​output from the feedback tap 53, and multiply the values ​​output from the taps 52-1 to 52-N by the values ​​output from the feedback tap 53. The AND circuits 55-1 to 55-(N-1) respectively output values ​​obtained by multiplying the values ​​output from the taps 52-1 to 52-(N-1) by the values ​​input from the feedback tap 53 to the XOR circuits 56-1 to 56-(N-1). The AND circuit 55-N outputs a value obtained by multiplying the value output from the tap 52-N by the value input from the feedback tap 53 to the XOR circuit 56-(N-1).

[0065] The XOR circuits 56-1 to 56-(N-1) are provided corresponding to the AND circuits 55-1 to 55-(N-1), respectively. The AND circuits 55-1 to 55-N and the XOR circuits 56-1 to 56-(N-1) are calculation circuits that calculate an exclusive OR on the value output from the tap to be fed back designated by the feedback tap 53, and feed back the calculated value. The XOR circuit 56-(N-1) calculates an exclusive OR on the value output from the AND circuit 55-N and the value output from the AND circuit 55-(N-1), and outputs the result to the XOR circuit 56-(N-2). The XOR circuits 56-2 to 56-(N-2) calculate an exclusive OR on the values ​​output from the XOR circuits 56-3 to 56-(N-1) and the values ​​output from the AND circuits 55-2 to 55-(N-2), respectively. The XOR circuits 56-2 to 56-(N-2) output the operation results to the XOR circuits 56-1 to 56-(N-3), respectively. The XOR circuit 56-1 performs an exclusive OR on the value output from the XOR circuit 56-2 and the value output from the AND circuit 55-1, and feeds back the operation result to the tap 52-1.

[0066] In the standby state, the reference sequence output unit 321 inputs the transmitting station operation time information to the shift register 51 of the random number reference sequence generation circuit 50 at the timing of generating a transmission standby UW at every predetermined periodic time. The reference sequence output unit 321 advances the clock time of the clock of the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. After shifting the shift register 51 a predetermined number of times, the reference sequence output unit 321 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence, and outputs the first random number reference sequence to the random number output unit 322. After outputting the first random number reference sequence, the reference sequence output unit 321 holds each value of the taps 52-1 to 52-N of the shift register 51.

[0067] When communication with the wireless communication device 40 is started, the reference sequence output unit 321 advances the clock time of the clock of the random number reference sequence generation circuit 50 by one while the corresponding values ​​of the first random number reference sequence are held in the taps 52-1 to 52-N. After the shift register 51 is shifted once, the reference sequence output unit 321 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a second random number reference sequence. The reference sequence output unit 321 outputs the second random number reference sequence to the random number output unit 322. After outputting the second random number reference sequence, the reference sequence output unit 321 holds the values ​​of the taps 52-1 to 52-N.

[0068] Similarly, when the reference sequence output unit 321 generates the (i-1)th transmission UW, it holds the values ​​of the taps 52-1 to 52-N and advances the clock time of the clock in the random number reference sequence generation circuit 50 by one before generating a radio frame. The reference sequence output unit 321 generates the i-th random number reference sequence by combining the values ​​P1 to PN output from the taps 52-1 to 52-N after the shift register 51 is shifted once. The reference sequence output unit 321 outputs the i-th random number reference sequence to the random number output unit 322. After outputting the i-th random number reference sequence, the reference sequence output unit 321 holds the values ​​of the taps 52-1 to 52-N.

[0069] When the reference sequence output unit 321 outputs the transmission standby UW and the transmission UW, the reference sequence output unit 321 may store each value of the taps 52-1 to 52-N of the shift register 51 in the storage unit 31. Then, the reference sequence output unit 321 may obtain each value of the taps 52-1 to 52-N from the storage unit 31 at the timing of generating the transmission UW, and input the obtained transmission UW to the shift register 51.

[0070] Returning to Fig. 3, the random number output unit 322 will be described. The random number output unit 322 holds a random number table T1. The random number output unit 322 receives an input of the first random number reference sequence output by the reference sequence output unit 321, and outputs a first output value to the conversion sequence output unit 323 based on the random number table T1. The random number output unit 322 also receives an input of the i-th random number reference sequence output by the reference sequence output unit 321, and outputs the i-th output value to the conversion sequence output unit 323 based on the random number table T1.

[0071] Here, the random number table T1 will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining an example of a random number table according to the second embodiment. The random number table T1 includes a left column in which candidate random number reference sequences that can be output by the reference sequence output unit 321 are set, and a right column in which output values ​​corresponding to the input random number reference sequence are set. For example, a value corresponding to the candidate random number reference sequence is set in the output value, and the output value is determined by generating random numbers in advance. For example, a 10-bit value consisting of a bit string of 0 and 1 is set in the output value. Note that the output value is not limited to 10 bits, and may be set to a number of bits of 26 bits or more, or any number of bits.

[0072] For example, when the reference sequence output unit 321 outputs “0000...0101” as a random number reference sequence, the random number output unit 322 inputs “0000...0101” output by the reference sequence output unit 321. The random number output unit 322 searches for “0000...0101” in the left column of the random number table T1, determines an output value corresponding to “0000...0101” from the right column of the random number table T1, and outputs the determined output value to the conversion sequence output unit 323.

[0073] Returning to Fig. 3, the conversion sequence output unit 323 will be described. The conversion sequence output unit 323 receives the output value output by the random number output unit 322 and outputs a conversion sequence that is a pseudo-random number sequence. The conversion sequence output unit 323 outputs a first conversion sequence based on a first output value as a transmission standby UW that can be used as a first transmission UW, and outputs an i-th conversion sequence based on an i-th output value as the i-th transmission UW.

[0074] The converted sequence output unit 323 includes a converted sequence generating circuit 80 that outputs a pseudo-random number sequence, and generates and outputs a converted sequence using the converted sequence generating circuit 80. Here, a configuration example of the conversion sequence generating circuit 80 will be described with reference to Fig. 7. Fig. 7 is a diagram showing a configuration example of the conversion sequence generating circuit according to the second embodiment.

[0075] The converted sequence generating circuit 80 is a circuit that outputs a GOLD sequence having a sequence length of 31 bits. The converted sequence generating circuit 80 may be a circuit that outputs an M sequence, or may be a circuit that outputs another sequence, and may have an arbitrary sequence length other than 31 bits. The converted sequence generating circuit 80 includes shift registers 81 and 83, and XOR circuits 85-1 to 85-3, 86-1 and 87.

[0076] The shift register 81 includes taps 82-1 to 82-5. The shift register 81 inputs the lowest five bits of the output value output by the random number output unit 322 to the taps 82-1 to 82-5. The shift register 81 inputs, for example, the lowest 1st to 5th bits of the output value output by the random number output unit 322 to the taps 82-1 to 82-5, respectively.

[0077] The shift register 83 includes taps 84-1 to 84-5. The shift register 83 inputs the most significant five bits of the output value output by the random number output unit 322 to the taps 84-1 to 84-5. The shift register 83 inputs, for example, the most significant 1st to 5th bits of the output value output by the random number output unit 322 to the taps 84-1 to 84-5, respectively.

[0078] A clock signal is input to the shift registers 81 and 83, and the values ​​input to the taps 82-1 to 82-5 and 84-1 to 84-5 are sequentially transmitted in synchronization with the clock signal. The clock signal is supplied by a clock included in the conversion sequence generating circuit 80, and operates at a constant repetition frequency.

[0079] The shift register 81 sequentially shifts the shift register 81 by advancing the clock time of the clock of the conversion sequence generating circuit 80 by one. The shift register 81 transmits (outputs) the value of the tap 82-1 to the tap 82-2 by advancing the clock time of the clock by one. The shift register 81 transmits the value of the tap 82-2 to the tap 82-3 and the XOR circuit 85-1 by advancing the clock time by one. The shift register 81 transmits the value of the tap 82-3 to the tap 82-4 and the XOR circuit 85-2 by advancing the clock time by one. The shift register 81 transmits the value of the tap 82-4 to the tap 82-5 and the XOR circuit 85-3 by advancing the clock time by one. The shift register 81 transmits the value of the tap 82-5 to the XOR circuit 85-3 and the XOR circuit 87 by advancing the clock time by one.

[0080] The shift register 83 sequentially shifts the shift register 83 by advancing the clock time of the clock of the conversion sequence generating circuit 80 by one. The shift register 83 transmits the value of the tap 84-1 to the tap 84-2 by advancing the clock time of the clock of the conversion sequence generating circuit 80 by one. The shift register 83 transmits the value of the tap 84-2 to the tap 84-3 and the XOR circuit 86-1 by advancing the clock time of the clock of the conversion sequence generating circuit 80 by one. The shift register 83 transmits the value of the tap 84-3 to the tap 84-4 by advancing the clock time by one. The shift register 83 transmits the value of the tap 84-4 to the tap 84-5 by advancing the clock time by one. The shift register 83 transmits the value of the tap 84-5 to the XOR circuit 86-1 and the XOR circuit 87 by advancing the clock time by one.

[0081] The XOR circuit 85-1 performs an exclusive OR on the value transmitted (output) from the tap 82-2 and the value output from the XOR circuit 85-2, and outputs the result of the operation to the tap 82-1. The XOR circuit 85-2 performs an exclusive OR on the value transmitted (output) from the tap 82-3 and the value output from the XOR circuit 85-3, and outputs the result of the operation to the XOR circuit 85-1. The XOR circuit 85-3 performs an exclusive OR on the values ​​transmitted (output) from the taps 82-4 and 82-5, and outputs the result of the operation to the XOR circuit 85-2.

[0082] The XOR circuit 86-1 performs an exclusive OR operation on the values ​​transmitted (output) from the taps 84-2 and 84-5, and outputs the operation result to the tap 84-1. The XOR circuit 87 performs an exclusive OR on the value output from the tap 82 - 5 and the value output from the tap 84 - 5 , and outputs the result of the operation to the converted sequence output unit 323 .

[0083] The number of XOR circuits included in the conversion sequence generating circuit 80 and their positions are determined based on one preferred pair selected for the GOLD sequence generated by the conversion sequence generating circuit 80. The preferred pair of the conversion sequence generating circuit 80 is an M sequence whose M sequence generating polynomial is [5,4,3,2] and an M sequence whose M sequence generating polynomial is [5,2]. Therefore, the number of XOR circuits provided corresponding to the shift register 81 is three. The XOR circuit 85-3 is placed at a position where an exclusive OR is calculated for the value of the tap 82-4 and the value of the tap 82-5. The XOR circuit 85-2 is placed at a position where an exclusive OR is calculated for the value of the tap 82-3, the value of the tap 82-4, and the value of the tap 82-5. The XOR circuit 85-1 is placed at a position where an exclusive OR is calculated for the value of the tap 82-2, the value of the tap 82-3, the value of the tap 82-4, and the value of the tap 82-5. Moreover, the number of XOR circuits provided corresponding to the shift register 83 is one, and the XOR circuit 86-1 is disposed at a position where an exclusive OR operation is performed on the value of the tap 84-2 and the value of the tap 84-5. Note that the preferred pairs of the conversion sequence generating circuit 80 are not limited to the above two M-sequence generating polynomials, and therefore the conversion sequence generating circuit 80 can be a circuit configured with different selectable preferred pairs.

[0084] In the standby state, the conversion sequence output unit 323 inputs the first output value output by the random number output unit 322 to the shift registers 81 and 83 of the conversion sequence generation circuit 80 at the timing of generating a transmission standby UW at every predetermined periodic time. The conversion sequence output unit 323 advances the clock time of the clock of the conversion sequence generation circuit 80 by one, and shifts the shift registers 81 and 83 by one. The conversion sequence output unit 323 holds the value output from the XOR circuit 87. The conversion sequence output unit 323 advances the clock time by another 30 times, and shifts the shift registers 81 and 83 by another 30 times, so that a total of 31 values ​​are output from the XOR circuit 87. The conversion sequence output unit 323 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. Conversion sequence output unit 323 generates a GOLD sequence by combining the 31 values ​​output from XOR circuit 87, and outputs the generated GOLD sequence to transmission unit 34 as a transmission standby UW that can be used as the first transmission UW. In the following description, the GOLD sequence output based on the first output value will be described as the first GOLD sequence, and the GOLD sequence output based on the i-th output value will be described as the i-th GOLD sequence.

[0085] When communication with the wireless communication device 40 is started, the conversion sequence output unit 323 inputs the i-th output value output by the random number output unit 322 to the shift registers 81 and 83 of the conversion sequence generation circuit 80. The conversion sequence output unit 323 advances the clock time of the clock of the conversion sequence generation circuit 80 31 times, thereby shifting the shift registers 81 and 83 31 times. The conversion sequence output unit 323 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. The conversion sequence output unit 323 generates the i-th GOLD sequence by combining the 31 values ​​output from the XOR circuit 87, and outputs the i-th GOLD sequence to the transmission unit 34 as the i-th transmission UW.

[0086] Returning to Fig. 3, the transmitting unit 34 will be described. The transmitting unit 34 corresponds to the transmitting unit 12 according to the first embodiment. When data is input to an input device such as a microphone included in the wireless communication device 30, or when data is input from another communication device, the transmitting unit 34 transitions the wireless communication device 30 to a communication state. The transmitting unit 34 divides data to be transmitted to the wireless communication device 40 into wireless frames.

[0087] The transmitter 34 uses the transmission standby UW generated immediately before the start of communication with the wireless communication device 40 as the first transmission UW, and generates a first wireless frame including the first transmission UW and transmission data for the first wireless data. The transmitter 34 transmits the first wireless frame to the wireless communication device 40. The transmitter 34 generates an i-th wireless frame including the i-th transmission UW and transmission data for the i-th wireless data. The transmitter 34 transmits the i-th wireless frame to the wireless communication device 40. The transmitter 34 may transmit a wireless frame including a symbol synchronization code, which is a code string for detecting symbol timing of a modulated signal, to the wireless communication device 40, and the symbol synchronization code may be referred to as an SSW (Symbol Sync Word).

[0088] Next, a description will be given of a configuration example of the wireless communication device 40. The wireless communication device 40 has a basically similar configuration to the wireless communication device 30. Therefore, the configuration example of the wireless communication device 40 will be described while omitting descriptions common to the configuration example of the wireless communication device 30 as appropriate.

[0089] The wireless communication device 40 includes a storage unit 41, a generation unit 42, and a reception unit 44. The storage unit 41 stores receiving station operation time information indicating operation time used for operation of the wireless communication device 40. The receiving station operation time information may be determined based on a reference time and an operation clock used for operation of the wireless communication device 40, or the operation clock may calculate the elapsed time from the reference time and determine the receiving station operation time information. The receiving station operation time information is operation time information corresponding to the transmitting station operation time information and has a certain error range from the transmitting station operation time information.

[0090] The receiving station operation time information may be configured to include 26 bits, including 9 bits for forming a date (month and day) and 17 bits for forming a time (hour, minute, and second). The receiving station operation time information may be configured, for example, with 4 bits indicating the month (January to December), 5 bits indicating the day (1st to 31st), 5 bits indicating the hour (0:00 to 23:00), 6 bits indicating the minute (0 minutes to 59 minutes), and 6 bits indicating the second (0 seconds to 59 seconds).

[0091] The generating unit 42 corresponds to the generating unit 21 in the first embodiment. The generating unit 42 is configured to be able to generate a receiving UW that is the same as the transmitting UW generated by the generating unit 32. Before communication with the wireless communication device 30 is started, the generating unit 42 generates a receiving standby UW that corresponds to the transmitting standby UW generated by the generating unit 32 based on the receiving station operation time information. The receiving standby UW is a receiving UW that can be used as the first receiving UW for receiving the first wireless frame transmitted immediately after the start of communication. In this embodiment, since the transmitting station operation time information and the receiving station operation time information are within a certain error, the generating unit 42 generates a receiving UW that is the same as the transmitting UW generated by the generating unit 32. The generating unit 42 generates a receiving standby UW based on the receiving station operation time information at the timing when the generating unit 32 generates a transmitting standby UW at a predetermined periodic time, and periodically updates the receiving standby UW.

[0092] When communication with the wireless communication device 30 is started, the generation unit 42 generates an i-th reception UW for receiving the wireless frame transmitted i-th from the start of communication based on the (i-1)-th reception UW for each wireless frame. When the wireless communication device 40 transitions to a communication state, the generation unit 42 determines that communication with the wireless communication device 30 has started. When communication with the wireless communication device 30 is started, the generation unit 42 uses the reception standby UW generated immediately before the start of communication as the first reception UW, updates the first reception UW (i-1) times for each wireless frame, and generates the i-th reception UW. Since the reception standby UW is used as the first reception UW, it can also be said that the generation unit 42 updates the reception standby UW generated immediately before the start of communication (i-1) times for each wireless frame to generate the i-th reception UW.

[0093] The generation unit 42 includes a reference sequence output unit 421 , a random number output unit 422 , and a conversion sequence output unit 423 . The reference sequence output unit 421 has basically the same configuration as the reference sequence output unit 321. Therefore, the description will be omitted as appropriate for the same parts as those in the reference sequence output unit 321. The reference sequence output unit 421 is configured to be capable of outputting a random number reference sequence which is a pseudo-random number sequence, and outputs the random number reference sequence to the random number output unit 422. The reference sequence output unit 421 is configured to be capable of generating a random number reference sequence identical to the random number reference sequence output by the reference sequence output unit 321.

[0094] In a standby state before communication is started, the reference sequence output unit 421 outputs a random number reference sequence, which is a pseudo-random number sequence, based on the receiving station operation time information and is the same as the random number reference sequence based on the transmitting station operation time information, at every predetermined period of time based on the receiving station operation time information. The reference sequence output unit 421 inputs the receiving station operation time information and outputs a first random number reference sequence based on the receiving station operation time information to the random number output unit 422.

[0095] When communication is started and wireless communication device 40 transitions to a communication state, reference sequence output unit 421 outputs an i-th random number reference sequence based on the (i-1)-th random number reference sequence for each wireless frame to random number output unit 422. Reference sequence output unit 421 outputs an i-th random number reference sequence that is the same as the i-th random number reference sequence output by reference sequence output unit 321.

[0096] The reference sequence output unit 421 includes the random number reference sequence generating circuit 50 shown in FIG. Here, the reference sequence output unit 421 will be described in detail with reference to FIG. 5. In a standby state, the reference sequence output unit 421 inputs the receiving station operation time information to the shift register 51 of the random number reference sequence generation circuit 50 at the timing of generating a reception standby UW at every predetermined periodic time. The reference sequence output unit 421 advances the clock time of the clock of the random number reference sequence generation circuit 50 by a predetermined number and shifts the shift register 51 a predetermined number of times. After shifting the shift register 51 a predetermined number of times, the reference sequence output unit 421 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence, and outputs the first random number reference sequence to the random number output unit 422. After outputting the first random number reference sequence, the reference sequence output unit 421 holds each value of the taps 52-1 to 52-N of the shift register 51.

[0097] When communication with the wireless communication device 30 is started, the reference sequence output unit 421 advances the clock time of the clock in the random number reference sequence generation circuit 50 by one while the corresponding values ​​of the first random number reference sequence are held in the taps 52-1 to 52-N. After the shift register 51 is shifted once, the reference sequence output unit 421 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a second random number reference sequence. The reference sequence output unit 421 outputs the second random number reference sequence to the random number output unit 422. After outputting the second random number reference sequence, the reference sequence output unit 421 holds the values ​​of the taps 52-1 to 52-N.

[0098] The reference sequence output unit 421 outputs a random number reference sequence for the second reception UW based on the reception standby UW that is the same as the transmission standby UW. Therefore, the reference sequence output unit 421 outputs the second reception UW that is the same as the second transmission UW.

[0099] The reference sequence output unit 421 similarly outputs the (i-1)th random number reference sequence, then holds each value of the taps 52-1 to 52-N, and advances the clock time of the clock in the random number reference sequence generation circuit 50 by one before generating a radio frame. The reference sequence output unit 421 generates the i-th random number reference sequence by combining the values ​​P1 to PN output from the taps 52-1 to 52-N after the shift register 51 is shifted once. The reference sequence output unit 421 outputs the i-th random number reference sequence to the random number output unit 422. The reference sequence output unit 421 outputs the i-th random number reference sequence, then holds each value of the taps 52-1 to 52-N.

[0100] Returning to Fig. 3, the random number output unit 422 will be described. The random number output unit 422 holds a random number table T1 that is the same as the random number table held by the random number output unit 322 shown in Fig. 6. The random number output unit 422 receives an input of the first random number reference sequence output by the reference sequence output unit 421, and outputs a first output value to the conversion sequence output unit 423 based on the random number table T1. The random number output unit 422 also receives an input of the i-th random number reference sequence output by the reference sequence output unit 421, and outputs the i-th output value to the conversion sequence output unit 423 based on the random number table T1.

[0101] The random number output unit 422 receives an input of the same random number reference sequence as the random number reference sequence output by the reference sequence output unit 321, and holds the same random number table T1 as the random number output unit 322, so that the random number output unit 422 outputs the same output value as the output value output by the random number output unit 322. In other words, the random number output unit 422 outputs the same first output value as the random number output unit 322, and outputs the same i-th output value as the random number output unit 322.

[0102] The converted sequence output unit 423 has a basically similar configuration to the converted sequence output unit 323. Therefore, in the following description, the configuration of the converted sequence output unit 423 will be described while appropriately omitting parts that are similar to the configuration of the converted sequence output unit 323. The converted sequence output unit 423 receives the output value output by the random number output unit 422 and outputs a converted sequence that is a pseudo-random number sequence. The converted sequence output unit 423 outputs a first converted sequence based on a first output value as a reception waiting UW that can be used as a first reception UW, and outputs an i-th converted sequence based on an i-th output value as an i-th reception UW.

[0103] The transformed sequence output unit 423 includes the transformed sequence generating circuit 80 shown in FIG. 7, and uses the transformed sequence generating circuit 80 to generate and output a GOLD sequence, which is a transformed sequence. In the standby state, the conversion sequence output unit 423 inputs the first output value output by the random number output unit 422 to the shift registers 81 and 83 of the conversion sequence generation circuit 80 at the timing of generating a reception standby UW at every predetermined periodic time. The conversion sequence output unit 423 advances the clock time of the clock of the conversion sequence generation circuit 80 31 times and shifts the shift registers 81 and 83 31 times. The conversion sequence output unit 423 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. The conversion sequence output unit 423 combines the 31 values ​​output from the XOR circuit 87 to generate the first GOLD sequence, and outputs the first GOLD sequence to the receiving unit 44 as a reception standby UW.

[0104] When communication with the wireless communication device 30 is started, the conversion sequence output unit 423 inputs the i-th output value output by the random number output unit 422 to the shift registers 81 and 83 of the conversion sequence generation circuit 80. The conversion sequence output unit 423 advances the clock time of the clock of the conversion sequence generation circuit 80 31 times, thereby shifting the shift registers 81 and 83 31 times. The conversion sequence output unit 423 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. The conversion sequence output unit 423 generates the i-th GOLD sequence by combining the 31 values ​​output from the XOR circuit 87, and outputs the i-th GOLD sequence to the receiving unit 44 as the i-th received UW.

[0105] Random number output unit 422 outputs the same output value as the output value of random number output unit 322, and converted sequence output unit 423 has the same converted sequence generation circuit 80 as converted sequence output unit 323. Therefore, converted sequence output unit 423 outputs a GOLD sequence that is the same as the GOLD sequence output by converted sequence output unit 323. Furthermore, since converted sequence output units 323 and 423 respectively output GOLD sequences as the transmission UW and reception UW, the reception UW is the same as the transmission UW.

[0106] Returning to FIG. 3, the receiving unit 44 will be described. The receiving unit 44 corresponds to the receiving unit 22 according to the first embodiment. The receiving unit 44 uses the reception standby UW generated immediately before the start of communication as the first reception UW, detects the first transmission UW that is the same as the first reception UW based on the first reception UW, and receives the first wireless frame including the first reception UW. When the receiving unit 44 detects the first transmission UW, it transitions the wireless communication device 40 to a communication state. The receiving unit 44 detects the i-th transmission UW that is the same as the i-th reception UW based on the i-th reception UW, and receives the i-th wireless frame including the i-th reception UW.

[0107] <Example of wireless communication system operation> Next, an operation example of the wireless communication system 200 according to the second embodiment will be described. First, an operation example showing the overall operation of the wireless communication system 200 according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing an operation example of the wireless communication system according to the second embodiment, and is a sequence diagram showing the overall operation of the wireless communication system according to the second embodiment. Fig. 8 is executed after the wireless communication devices 30 and 40 are started up.

[0108] In the standby state, the generating unit 32 generates a transmission standby UW that can be used as the first transmission UW to be added to the first radio frame based on the transmitting station operation time information, and updates the transmission standby UW (step S11). In the standby state, step S11 is repeatedly executed periodically at a predetermined period of time.

[0109] In the standby state, the generation unit 42 generates a reception standby UW that can be used as the first reception UW for receiving the first radio frame based on the receiving station operation time information, and updates the reception standby UW (step S12). Since the transmitting station operation time information and the receiving station operation time information are within a certain error range, the generation unit 42 generates a reception standby UW that is the same as the transmission standby UW at the timing when the generation unit 32 generates the transmission standby UW. In the standby state, step S12 is executed repeatedly and periodically.

[0110] When the transmitting unit 34 receives the data to be transmitted to the wireless communication device 40, the transmitting unit 34 causes the wireless communication device 30 to transition to a communication state, and the wireless communication device 30 transitions to a communication state (step S13). The transmitter 34 divides the data to be transmitted to the wireless communication device 40, uses the transmission standby UW generated immediately before the start of communication as the first transmission UW, and transmits a first wireless frame including the first transmission UW and the divided data to the wireless communication device 40 (step S14).

[0111] The receiving unit 44 uses the reception waiting UW generated immediately before the start of communication as the first reception UW, detects the first transmission UW that is identical to the first reception UW based on the first reception UW, and receives the first wireless frame including the first transmission UW (step S15). When the receiver 44 detects the first transmission UW, it transitions the wireless communication device 40 to a communication state, and the wireless communication device 40 transitions to a communication state (step S16).

[0112] The generation unit 32 generates a second transmission UW based on the first transmission UW (step S17). Step S17 is executed after the transmission unit 34 transmits the first wireless frame to the wireless communication device 40 and before the generation of the second wireless frame.

[0113] The generation unit 42 generates a second received UW based on the first received UW (step S18). Step S18 is executed when the reception unit 44 detects the first transmitted UW and before the second wireless frame is transmitted from the wireless communication device 40. The generation unit 42 generates a second received UW that is the same as the second transmitted UW based on the same received UW that is the same as the transmitted UW. Note that step S18 may or may not be executed at the same timing as step S17.

[0114] The transmitter 34 transmits the second wireless frame including the second transmission UW and the divided data to the wireless communication device 40 (step S19). Based on the second received UW, the receiving unit 44 detects a second transmitted UW that is identical to the second received UW, and receives a second wireless frame including a second transmitted UW that is identical to the second received UW (step S20).

[0115] After that, the wireless communication system 200 repeatedly executes steps S17 to S20 until the communication is completed. When the communication is completed, each of the wireless communication devices 30 and 40 transitions from the communication state to the standby state, and repeatedly executes steps S11 and S12 until the next communication is started.

[0116] The operations in steps S17 to S20 can be generalized and described as follows. The generation unit 32 generates the i-th transmission UW based on the (i-1)-th transmission UW (step S17). Step S17 is executed after the transmission unit 34 transmits the (i-1)-th wireless frame to the wireless communication device 40 and before generating the i-th wireless frame.

[0117] The generation unit 42 generates the i-th reception UW based on the reception waiting UW, which is the (i-1)-th reception UW (step S18). Step S18 is executed before the reception unit 44 detects the (i-1)-th transmission UW and the i-th wireless frame is transmitted from the wireless communication device 30. The generation unit 42 generates the i-th reception UW that is the same as the i-th transmission UW.

[0118] The transmitter 34 transmits the i-th wireless frame including the i-th transmission UW and the divided data to the wireless communication device 40 (step S19). Based on the i-th received UW, the receiving unit 44 detects the i-th transmitted UW that is identical to the i-th received UW, and receives the i-th wireless frame that includes the i-th transmitted UW that is identical to the i-th received UW (step S20).

[0119] <Details of step S11> Next, the details of the operation executed in step S11 in Fig. 8 will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of the operation of the wireless communication system according to the second embodiment. Fig. 9 is a flowchart for explaining the details of the operation executed by the generation unit 32 in step S11 in Fig. 8, which is repeatedly executed periodically at a predetermined period of time.

[0120] The reference sequence output unit 321 inputs the transmitting station operation time information to the shift register 51 of the random number reference sequence generation circuit 50, and outputs the first random number reference sequence to the random number output unit 322 (step S111).

[0121] The reference sequence output unit 321 inputs each of the multiple bits constituting the transmitting station operation time information to each of the taps 52-1 to 52-N. The reference sequence output unit 321 advances the clock time of the clock in the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. The reference sequence output unit 321 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence, and outputs the first random number reference sequence to the random number output unit 322. After outputting the first random number reference sequence, the reference sequence output unit 321 holds the value of the shift register 51.

[0122] The random number output unit 322 receives the first random number reference sequence, and outputs the first output value to the converted sequence output unit 323 based on the random number table T1 (step S112). The conversion sequence output unit 323 inputs the first output value to the shift registers 81 and 83 of the conversion sequence generating circuit 80 (step S113).

[0123] The converted sequence output unit 323 inputs the lowest 5 bits of the output value output by the random number output unit 322 to taps 82-1 to 82-5 of the shift register 81. The converted sequence output unit 323 inputs the highest 5 bits of the output value output by the random number output unit 322 to taps 84-1 to 84-5 of the shift register 83. The converted sequence output unit 323 advances the clock time of the clock in the converted sequence generating circuit 80 31 times, and shifts the shift registers 81 and 83 31 times.

[0124] The conversion sequence output unit 323 generates a first GOLD sequence based on the 31 values ​​output from the XOR circuit 87, and outputs the first GOLD sequence to the transmission unit 34 as a transmission waiting UW that can be used as the first transmission UW (step S114).

[0125] <Details of step S12> Next, the operation executed in step S12 in Fig. 8 will be described in detail. Step S12 in Fig. 8 is basically the same as step S11 in Fig. 8, so it will be described with reference to Fig. 9, with some explanation omitted as appropriate. Step S12 in Fig. 8 is executed periodically and repeatedly at a predetermined cycle time. The difference between step S11 and step S12 is that the transmitting station operation time information in step S11 is replaced with the receiving station operation time information, and the transmission standby UW in step S11 is replaced with the reception standby UW.

[0126] The reference sequence output unit 421 inputs the receiving station operation time information to the shift register 51 of the random number reference sequence generation circuit 50, and outputs the first random number reference sequence to the random number output unit 322 (step S111).

[0127] The reference sequence output unit 421 inputs each of the multiple bits constituting the receiving station operation time information to each of the taps 52-1 to 52-N. The reference sequence output unit 421 advances the clock time of the clock in the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. The reference sequence output unit 421 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence, and outputs the first random number reference sequence to the random number output unit 422. After outputting the first random number reference sequence, the reference sequence output unit 321 holds the value of the shift register 51.

[0128] The random number output unit 422 receives the first random number reference sequence, and outputs the first output value to the converted sequence output unit 423 based on the random number table T1 (step S112). The conversion sequence output unit 423 inputs the first output value to the shift registers 81 and 83 of the conversion sequence generating circuit 80 (step S113).

[0129] The converted sequence output unit 423 inputs the lowest 5 bits of the output value output by the random number output unit 422 to taps 82-1 to 82-5 of the shift register 81. The converted sequence output unit 423 inputs the highest 5 bits of the output value output by the random number output unit 422 to taps 84-1 to 84-5 of the shift register 83. The converted sequence output unit 423 advances the clock time of the clock in the converted sequence generating circuit 80 31 times, and shifts the shift registers 81 and 83 31 times.

[0130] The conversion sequence output unit 423 generates a first GOLD sequence based on the 31 values ​​output from the XOR circuit 87, and outputs the first GOLD sequence to the receiving unit 44 as a receiving waiting UW that can be used as the first receiving UW (step S114).

[0131] <Details of step S17> Next, the operation of the generation unit 32 generating the i-th transmission UW in step S17 in Fig. 8 will be described in detail with reference to Fig. 10. Fig. 10 is a diagram showing an example of the operation of the wireless communication system according to the second embodiment. Fig. 10 is a flowchart for explaining the details of the operation executed by the generation unit 32 in step S17 in Fig. 8. Fig. 10 is repeatedly executed for each wireless frame. Note that Fig. 10 is executed in a state where the shift register 51 of the reference sequence output unit 321 holds the value of the (i-1)-th random number reference sequence.

[0132] The reference sequence output unit 321 outputs the i-th random number reference sequence based on the (i-1)-th random number reference sequence held in the shift register 51 of the random number reference sequence generation circuit 50 to the random number output unit 322 (step S171).

[0133] The reference sequence output unit 321 advances the clock time of the clock in the random number reference sequence generation circuit 50 by one, and shifts once the shift register 51 holding the value of the (i-1)th random number reference sequence. The reference sequence output unit 321 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate the ith random number reference sequence, and outputs the ith random number reference sequence to the random number output unit 322.

[0134] The random number output unit 322 receives the i-th random number reference sequence, and outputs the i-th output value to the converted sequence output unit 323 based on the random number table T1 (step S172). The conversion sequence output unit 323 inputs the i-th output value to the shift registers 81 and 83 of the conversion sequence generating circuit 80 (step S173).

[0135] The converted sequence output unit 323 inputs the lowest 5 bits of the output value output by the random number output unit 322 to taps 82-1 to 82-5 of the shift register 81. The converted sequence output unit 323 inputs the highest 5 bits of the output value output by the random number output unit 322 to taps 84-1 to 84-5 of the shift register 83. The converted sequence output unit 323 advances the clock time of the clock in the converted sequence generating circuit 80 31 times, and shifts the shift registers 81 and 83 31 times.

[0136] The converted sequence output unit 323 generates the i-th GOLD sequence based on the 31 values ​​output from the XOR circuit 87, and outputs the i-th GOLD sequence to the transmitting unit 34 as the i-th transmission UW (step S174).

[0137] <Details of step S18> Next, the operation performed in step S18 of Fig. 8 will be described in detail. Step S18 of Fig. 8 is basically the same as step S17 of Fig. 8, so it will be described with reference to Fig. 10, with some explanation omitted as appropriate. Step S18 of Fig. 8 is repeatedly executed for each radio frame. Note that the difference between step S17 and step S18 is that the transmission UW in step S17 is replaced with the reception UW. Also, step S18 of Fig. 8 is executed in a state where shift register 51 holds the value of the (i-1)th random number reference sequence for the (i-1)th reception UW.

[0138] The reference sequence output unit 421 outputs the i-th random number reference sequence based on the (i-1)-th random number reference sequence held in the shift register 51 of the random number reference sequence generation circuit 50 to the random number output unit 422 (step S171).

[0139] The reference sequence output unit 421 advances by one clock time the clock that supplies a clock signal to the random number reference sequence generation circuit 50, and shifts once the shift register 51 that holds the value of the (i-1)th random number reference sequence. The reference sequence output unit 421 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate the ith random number reference sequence, and outputs the ith random number reference sequence to the random number output unit 422.

[0140] The random number output unit 422 receives the i-th random number reference sequence, and outputs the i-th output value to the converted sequence output unit 423 based on the random number table T1 (step S172). The conversion sequence output unit 423 inputs the i-th output value to the shift registers 81 and 83 of the conversion sequence generating circuit 80 (step S173).

[0141] The converted sequence output unit 423 inputs the lowest 5 bits of the output value output by the random number output unit 422 to taps 82-1 to 82-5 of the shift register 81. The converted sequence output unit 423 inputs the highest 5 bits of the output value output by the random number output unit 422 to taps 84-1 to 84-5 of the shift register 83. The converted sequence output unit 423 advances the clock time of the clock in the converted sequence generating circuit 80 31 times, and shifts the shift registers 81 and 83 31 times.

[0142] The converted sequence output unit 423 generates the i-th GOLD sequence based on the 31 values ​​output from the XOR circuit 87, and outputs the i-th GOLD sequence to the receiving unit 44 as the i-th received UW (step S174).

[0143] As described above, the wireless communication device 30 generates a different transmission UW for each wireless frame transmitted to the wireless communication device 40, and therefore, it is possible to prevent a third party from eavesdropping on the communication contents. In addition, the wireless communication device 30 generates a transmission standby UW to be used as the first transmission UW using the transmission station operation time information, and therefore, it is possible to generate a different transmission UW each time communication is performed with the wireless communication device 40. Since the first transmission UW is different for each communication with the wireless communication device 40, the wireless communication device 30 can generate a different i-th transmission UW each time communication is performed with the wireless communication device 40. Therefore, even if a third party continuously monitors the communication between the wireless communication device 30 and the wireless communication device 40, it is not possible to grasp the transmission UW used in the communication between the wireless communication device 30 and the wireless communication device 40. Therefore, according to the wireless communication device 30 according to the second embodiment, it is possible to prevent the communication contents from being eavesdropped on.

[0144] Furthermore, the wireless communication device 40 generates a reception standby UW to be used as the first reception UW, which is the same as the transmission standby UW to be used as the first transmission UW, based on the reception station operation time information. The wireless communication device 40 generates an i-th reception UW that is the same as the i-th transmission UW. Therefore, even if the wireless communication device 30 generates a different transmission UW for each wireless frame and for each communication, it is possible to detect the transmission UW included in the wireless frame transmitted from the wireless communication device 30 and receive the wireless frame. In other words, the wireless communication system 200 including the wireless communication device 30 and the wireless communication device 40 can perform normal communication while preventing a third party from eavesdropping on the communication contents.

[0145] Furthermore, in the standby state before communication is started, the wireless communication devices 30 and 40 periodically update the transmission standby UW and the reception standby UW at a predetermined cycle time. Therefore, the wireless communication system 200 according to the second embodiment can suppress the interception of communication contents more than the first embodiment.

[0146] Furthermore, since the wireless communication devices 30 and 40 update the transmission UW and the reception UW for each wireless frame and each communication, a third party cannot generate a UW used in the communication between the wireless communication devices 30 and 40. Therefore, a third party cannot generate jamming radio waves by duplicating the UW used in the communication between the wireless communication devices 30 and 40, for example. Furthermore, even if a third party transmits radio waves for the purpose of jamming the communication, the wireless communication device 40 does not receive the radio waves because the UW is different. That is, by using the wireless communication system 200 according to the present embodiment, a third party cannot generate effective jamming radio waves, and cannot transmit effective jamming radio waves. Therefore, the wireless communication system 200 according to the second embodiment can prevent a third party from eavesdropping on the communication contents and can avoid attacks by a third party by jamming the communication.

[0147] (Modification) In the second embodiment, the generation unit 32 may not include the random number output unit 322. That is, the generation unit 32 may include the reference sequence output unit 321 and the transformation sequence output unit 323. Similarly, the generation unit 42 may not include the random number output unit 422, but may include the reference sequence output unit 421 and the transformation sequence output unit 423.

[0148] In this case, the reference sequence output unit 321 selects any 10 bits from P1 to PN output from the random number reference sequence generating circuit 50, and outputs them to the conversion sequence output unit 323. The conversion sequence output unit 323 can be realized by inputting the lower 5 bits of the selected 10 bits to the shift register 81 and the upper 5 bits to the shift register 83. The reference sequence output unit 421 selects the same 10 bits as the 10 bits selected by the reference sequence output unit 321 from P1 to PN output from the random number reference sequence generating circuit 50, and outputs them to the conversion sequence output unit 423. The conversion sequence output unit 423 can be realized by inputting the lower 5 bits of the selected 10 bits to the shift register 81 and the upper 5 bits to the shift register 83. In this way, even if the generation units 32 and 42 in the second embodiment do not include the random number output units 322 and 422, respectively, the same effect as that of the second embodiment can be obtained.

[0149] (Embodiment 3) Next, a description will be given of embodiment 3. Embodiment 3 is an improved example of embodiment 2. Note that a modified example of embodiment 2 may be applied to embodiment 3. <Summary> First, before describing the details of the third embodiment, an overview of the third embodiment will be described. In the second embodiment, it has been described that the error between the transmitting station operation time information and the receiving station operation time information is within a certain range, and the same transmitting UW and receiving UW are generated. However, it is also assumed that the error between the transmitting station operation time information and the receiving station operation time information is large, and the transmitting UW and receiving UW are not the same. In this case, the wireless communication device, which is the receiving station, cannot detect the transmitting UW included in the transmitted wireless frame, and normal communication cannot be performed. Therefore, in this embodiment, normal communication is achieved even when the error between the transmitting station operation time information and the receiving station operation time information is large, and the transmitting UW and receiving UW are not the same.

[0150] An overview of the operation of the wireless communication devices 110 and 120 according to the third embodiment will be described with reference to Fig. 11. Fig. 11 is a diagram for explaining the overview of the operation of the wireless communication device according to the third embodiment. Fig. 11 shows the generation timing of UWs generated in the wireless communication devices 110 and 120 and the generated UWs.

[0151] The horizontal axis in Fig. 11 indicates time. The upper side of Fig. 11 indicates the generation timing of a UW generated in wireless communication device 110, which is a transmitting station, and the generated UW. The lower side of Fig. 11 indicates the generation timing of a UW generated in wireless communication device 120, which is a receiving station, and the generated UW. Note that, similar to Fig. 4, UW(t)0 indicates a UW (transmitting UW or receiving UW) generated when the operation time indicated by the operation time information (transmitting station operation time information or receiving station operation time information) is time t. Also, for example, UW(t+2)2 indicates a UW in which UW(t+2)0, which is a UW generated based on the transmitting station operation time information when the operation time is time (t+2), has been updated twice.

[0152] In the standby state, wireless communication device 110, which is the transmitting station, generates a transmission standby UW that can be used as the first transmission UW at predetermined periodic times based on transmitting station operation time information, similar to embodiment 2. As shown in Fig. 11, wireless communication device 110 generates a transmission standby UW at operation times (t+1), (t+2), ..., which are used for the operation of wireless communication device 110.

[0153] In the standby state, the wireless communication device 120, which is the receiving station, generates a reception standby UW to be used as the first receiving UW at every predetermined period of time based on the receiving station operation time information. 11, assume that there is a time error of Δt between the operation time of wireless communication device 120 and the operation time of wireless communication device 110. In this case, when wireless communication device 120 generates a standby UW when wireless communication device 120 operates at time (t+1), time (t+2), ..., the reception standby UW may differ from the transmission standby UW generated by wireless communication device 110.

[0154] Therefore, the wireless communication device 120 generates a reception standby UW every predetermined period, and further generates a first candidate UW based on the receiving station operation time information corresponding to the operation time one period before, and a second candidate UW based on the receiving station operation time information corresponding to the operation time one period after. Specifically, as shown in FIG. 11, for example, when the operation time of the wireless communication device 120 is time (t+1), the wireless communication device 120 generates a reception standby UW based on the receiving station operation time information corresponding to time (t+1). Furthermore, the wireless communication device 120 generates a first candidate UW based on the receiving station operation time information corresponding to time t one period before time (t+1), and generates a second candidate UW based on the receiving station operation time information corresponding to time (t+2) one period after time (t+1). In this way, the wireless communication device 120 generates a reception standby UW, a first candidate UW, and a second candidate UW every predetermined period in the standby state so that normal communication can be performed even if the same reception UW as the transmission UW is not generated. When communication is started, the wireless communication device 120 is configured to detect the first transmission UW based on the reception standby UW, the first candidate UW, and the second candidate UW, and to receive the first wireless frame 1_1.

[0155] Furthermore, when communication is started, the wireless communication device 110 transmits a first wireless frame 1_1 in which the transmitting station operation time information used to generate the first transmission UW is set so that the wireless communication device 120 can generate a receiving UW identical to the second transmission UW. Specifically, the wireless communication device 110 sets the transmitting station operation time information used to generate the first transmission UW in the control header of the first wireless frame 1_1 immediately after the start of communication, and transmits the first wireless frame 1_1 including the transmitting station operation time information to the wireless communication device 120. The wireless communication device 120 acquires the transmitting station operation time information used to generate the first transmission UW from the received first wireless frame 1_1 based on the reception waiting UW, the first candidate UW, and the second candidate UW. The wireless communication device 120 generates a receiving UW identical to the second transmission UW based on the acquired transmitting station time information.

[0156] In this way, wireless communication device 110 notifies wireless communication device 120 of the transmitting station operation time information used to generate the first transmitted UW, thereby notifying wireless communication device 120 of the operation time at which the transmitted UW was generated. Furthermore, wireless communication device 120 can ascertain the operation time at which the transmitted UW was generated based on the notified transmitting station operation time information. Wireless communication device 120 generates a received UW based on the notified transmitting station operation time information so that the second received UW is identical to the transmitted UW, thereby realizing normal communication even if there is an error in the operation time and the transmitted UW and the received UW are not identical.

[0157] <Example of wireless communication system configuration> A configuration example of a wireless communication system 400 according to the third embodiment will be described with reference to Fig. 12. Fig. 12 is a diagram showing a configuration example of a wireless communication system according to the third embodiment. The wireless communication system 400 includes a wireless communication device 110 and a wireless communication device 120. The wireless communication system 400 is basically the same as the second embodiment, except that the wireless communication devices 30 and 40 according to the second embodiment are replaced with the wireless communication devices 110 and 120, respectively. Therefore, a description of the configuration example of the wireless communication system 400 will be omitted.

[0158] <Example of wireless communication device configuration> Next, the wireless communication device 110 will be described. The wireless communication device 110 includes a storage unit 31, a generation unit 32, and a transmission unit 111. The wireless communication device 110 has a configuration in which the transmission unit 34 according to the second embodiment is replaced with the transmission unit 111. The configuration examples of the storage unit 31 and the generation unit 32 are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0159] When data is input to an input device included in the wireless communication device 110, or when data is input from another communication device, the transmission unit 111 transitions the wireless communication device 110 to a communication state. The transmission unit 111 divides data to be transmitted to the wireless communication device 120 into radio frames.

[0160] The transmitting unit 111 acquires the transmitting station operation time information used to generate the transmission standby UW generated immediately before the start of communication from the generating unit 32. In other words, the transmitting unit 111 acquires from the generating unit 32 the transmitting station operation time information used to generate the first transmission UW generated before transitioning to a communication state.

[0161] The transmitter 111 uses the transmission standby UW as the first transmission UW, and sets the first transmission UW and the acquired transmission station operation time information in the control header of the first wireless frame. The transmitter 111 generates a first wireless frame including the first transmission UW, the acquired transmission station operation time information, and transmission data for the first wireless frame. The transmitter 111 transmits the first wireless frame to the wireless communication device 120. The transmitter 111 generates an i-th wireless frame including the i-th transmission UW and transmission data for the i-th wireless data, and transmits the i-th wireless frame to the wireless communication device 120.

[0162] Next, the wireless communication device 120 will be described. The wireless communication device 120 includes a storage unit 121, a generating unit 122, and a receiving unit 124. The wireless communication device 120 has a configuration in which the storage unit 41, the generating unit 42, and the receiving unit 44 according to the second embodiment are replaced with the storage unit 121, the generating unit 122, and the receiving unit 124, respectively. Note that, regarding the configuration of the wireless communication device 120, the same contents as those in the second embodiment will be appropriately omitted in the description.

[0163] The storage unit 121 stores the receiving station operation time information. The storage unit 121 stores the reception standby UW, the first candidate UW, and the second candidate UW generated by the generation unit 122.

[0164] Before communication with the wireless communication device 110 is started, the generating unit 122 generates a reception standby UW corresponding to the transmission standby UW based on the receiving station operation time information at the timing of generating the reception standby UW at every predetermined period. At the operation time predetermined between the wireless communication device 110 and the wireless communication device 120, the generating unit 122 generates a reception standby UW corresponding to the transmission standby UW based on the receiving station operation time information. In other words, if the error between the operation time of the wireless communication device 110 and the operation time of the wireless communication device 120 is equal to or less than a certain value, the generating unit 122 generates a reception standby UW based on the receiving station operation time information at the operation time when the transmission standby UW and the reception standby UW are the same. At the timing of generating the reception standby UW, the generating unit 122 generates a first candidate UW based on one-period-before time information indicating the receiving station operation time information one period before the current time. The generating unit 122 generates a second candidate UW based on one-period-after time information indicating the receiving station operation time information one period after the current time.

[0165] When communication with the wireless communication device 110 is started, the generation unit 122 acquires the transmitting station operation time information included in the control header of the first wireless frame from the reception unit 124. The generation unit 122 identifies a receiving UW that is the same as the transmitting UW based on the acquired transmitting station operation time information from among the reception standby UW, the first candidate UW, and the second candidate UW. The generation unit 122 updates the identified receiving UW and generates a second receiving UW for the second wireless frame. For the third and subsequent receiving UWs, the generation unit 122 generates the i-th receiving UW based on the (i-1)-th receiving UW for each wireless frame, as in the second embodiment.

[0166] The generation unit 122 includes a reference sequence output unit 1221 , a random number output unit 1222 , and a converted sequence output unit 1223 . The reference sequence output unit 1221 includes a random number reference sequence generating circuit 50, and generates and outputs a random number reference sequence using the random number reference sequence generating circuit 50. At the timing of generating a reception standby UW, the reference sequence output unit 1221 calculates one cycle ago time information indicating the operating time information one cycle ago from the current time, and one cycle later time information indicating the operating time information one cycle later from the current time.

[0167] In a standby state, the reference sequence output unit 1221 inputs receiving station operation time information to the shift register 51 of the random number reference sequence generation circuit 50 at the timing of generating a reception standby UW at every predetermined periodic time. The reference sequence output unit 1221 advances the clock time of the clock in the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. The reference sequence output unit 1221 combines values ​​P1 to PN output from taps 52-1 to 52-N to generate a first random number reference sequence for generating a reception standby UW, and outputs the first random number reference sequence for generating a reception standby UW to the random number output unit 1222.

[0168] In a standby state, the reference sequence output unit 1221 inputs one-cycle previous time information to the shift register 51 of the random number reference sequence generation circuit 50 at the timing of generating a reception standby UW every predetermined period time. The reference sequence output unit 1221 advances the clock time of the clock in the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. The reference sequence output unit 1221 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence for the first candidate UW, and outputs the first random number reference sequence for the first candidate UW to the random number output unit 1222.

[0169] In a standby state, the reference sequence output unit 1221 inputs one-cycle later time information to the shift register 51 of the random number reference sequence generation circuit 50 at the timing of generating a reception standby UW every predetermined period time. The reference sequence output unit 1221 advances the clock time of the clock of the random number reference sequence generation circuit 50 by a predetermined number, and shifts the shift register 51 a predetermined number of times. The reference sequence output unit 1221 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a first random number reference sequence for the second candidate UW, and outputs the first random number reference sequence for the second candidate UW to the random number output unit 1222.

[0170] When communication with wireless communication device 110 is started and the first wireless frame is received, reference sequence output unit 1221 acquires transmitting station operation time information included in the control header of the first wireless frame from receiving unit 124. Reference sequence output unit 1221 reads out the reception standby UW, the first candidate UW, and the second candidate UW from memory unit 121, and identifies a receiving UW that is the same as the transmitting UW based on the acquired transmitting station operation time information, from among the reception standby UW, the first candidate UW, and the second candidate UW.

[0171] The reference sequence output unit 1221 may determine whether the receiving station operation time information used to generate the reception standby UW, the first candidate UW, and the second candidate UW matches the acquired transmission station operation time information, and identify a receiving UW that is identical to the transmitting UW based on the acquired transmission station operation time information. Alternatively, the reference sequence output unit 1221 may generate a receiving UW based on the acquired transmission station operation time information, and identify a receiving UW that matches the first transmitting UW among the reception standby UW, the first candidate UW, and the second candidate UW.

[0172] The reference sequence output unit 1221 may correct the receiving station operation time information based on the acquired transmitting station operation time information by overwriting the receiving station operation time information stored in the storage unit 121 with the acquired transmitting station operation time information. By correcting the receiving station operation time information based on the acquired transmitting station operation time information, the reference sequence output unit 1221 can suppress an increase in the error between the receiving station operation time information and the transmitting station operation time information.

[0173] The reference sequence output unit 1221 inputs the identified received UW to the shift register 51 of the random number reference sequence generation circuit 50. The reference sequence output unit 1221 advances the clock time of the clock in the random number reference sequence generation circuit 50 by one, and shifts the shift register 51 once. The reference sequence output unit 1221 combines the values ​​P1 to PN output from the taps 52-1 to 52-N to generate a second random number reference sequence, and outputs the second random number reference sequence to the random number output unit 1222. After outputting the second random number reference sequence, the reference sequence output unit 1221 holds each value of the taps 52-1 to 52-N of the shift register 51.

[0174] The reference sequence output unit 1221 generates the third and subsequent received UWs, as in the second embodiment. With the (i-1)th random number reference sequence held in the shift register 51, the reference sequence output unit 1221 advances the clock time of the clock in the random number reference sequence generation circuit 50 by one. The reference sequence output unit 1221 combines values ​​P1 to PN output from taps 52-1 to 52-N to generate the i-th random number reference sequence, and outputs the i-th random number reference sequence to the random number output unit 1222. After outputting the i-th random number reference sequence, the reference sequence output unit 1221 holds each value of the taps 52-1 to 52-N.

[0175] The random number output unit 1222 corresponds to the random number output unit 422 according to the second embodiment, and has a basically similar configuration to the random number output unit 422. Therefore, the description of the configuration of the random number output unit 1222 being the same as that of the random number output unit 422 will be omitted as appropriate. The random number output unit 1222 receives the first random number reference sequence for the reception standby UW output by the reference sequence output unit 1221, and outputs the first output value for the reception standby UW to the conversion sequence output unit 1223 based on the random number table T1. The random number output unit 1222 receives the first random number reference sequence for the first candidate UW output by the reference sequence output unit 1221, and outputs the first output value for the first candidate UW to the conversion sequence output unit 1223 based on the random number table T1. The random number output unit 1222 receives the first random number reference sequence for the second candidate UW output by the reference sequence output unit 1221, and outputs the first output value for the second candidate UW to the conversion sequence output unit 1223 based on the random number table T1. The random number output unit 1222 also receives the i-th random number reference sequence output by the reference sequence output unit 1221, and outputs the i-th output value to the conversion sequence output unit 1223 based on the random number table T1.

[0176] The converted sequence output unit 1223 corresponds to the converted sequence output unit 423 according to the second embodiment, and has basically the same configuration as the converted sequence output unit 423. Therefore, regarding the configuration of the converted sequence output unit 1223, descriptions that are similar to that of the converted sequence output unit 423 will be omitted as appropriate.

[0177] In the standby state, the conversion sequence output unit 1223 inputs the first output value for the reception standby UW output by the random number output unit 1222 to the shift registers 81 and 83 of the conversion sequence generation circuit 80 at the timing of generating the reception standby UW at every predetermined period time. The conversion sequence output unit 1223 advances the clock time of the clock of the conversion sequence generation circuit 80 31 times and shifts the shift registers 81 and 83 31 times. The conversion sequence output unit 1223 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. The conversion sequence output unit 1223 combines the 31 values ​​output from the XOR circuit 87 to generate the first GOLD sequence, and outputs the first GOLD sequence to the receiving unit 124 as the reception standby UW. The conversion sequence output unit 1223 stores the reception standby UW in the storage unit 121.

[0178] In the standby state, the conversion sequence output unit 1223 inputs the first output value for the first candidate UW output by the random number output unit 1222 to the shift registers 81 and 83 of the conversion sequence generation circuit 80 at the timing of generating a reception standby UW at each predetermined periodic time. The conversion sequence output unit 1223 generates a first GOLD sequence by combining the 31 values ​​output from the XOR circuit 87 in the same manner as the reception standby UW, and outputs the first GOLD sequence to the receiving unit 124 as the first candidate UW. The conversion sequence output unit 1223 stores the first candidate UW in the memory unit 121.

[0179] In the standby state, the conversion sequence output unit 1223 inputs the first output value for the second candidate UW output by the random number output unit 1222 to the shift registers 81 and 83 of the conversion sequence generation circuit 80 at the timing of generating a reception standby UW at every predetermined periodic time. The conversion sequence output unit 1223 generates a first GOLD sequence by combining the 31 values ​​output from the XOR circuit 87 in the same manner as the reception standby UW, and outputs the first GOLD sequence to the receiving unit 124 as the second candidate UW. The conversion sequence output unit 1223 stores the second candidate UW in the memory unit 121.

[0180] When communication with the wireless communication device 30 is started, the conversion sequence output unit 1223 inputs the i-th output value output by the random number output unit 1222 to the shift registers 81 and 83 of the conversion sequence generation circuit 80. The conversion sequence output unit 1223 advances the clock time of the clock of the conversion sequence generation circuit 80 31 times, thereby shifting the shift registers 81 and 83 31 times. The conversion sequence output unit 1223 holds the value output from the XOR circuit 87 every time the shift registers 81 and 83 are shifted. The conversion sequence output unit 1223 generates the i-th GOLD sequence by combining the 31 values ​​output from the XOR circuit 87, and outputs the i-th GOLD sequence to the reception unit 124 as the i-th reception UW.

[0181] The receiving unit 124 receives a radio frame including any one of the reception standby UW, the first candidate UW, and the second candidate UW used as the first reception UW as the first radio frame. The receiving unit 124 detects a first transmission UW based on the reception standby UW, the first candidate UW, and the second candidate UW. The receiving unit 124 receives a radio frame including a first transmission UW that is the same as any one of the reception standby UW, the first candidate UW, and the second candidate UW as the first radio frame. The receiving unit 124 acquires the transmission station operation time information used to generate the first transmission UW from the control header of the first radio frame, and transmits the acquired transmission station operation time information to the generating unit 122. When the receiving unit 124 detects the first transmission UW, it transitions the wireless communication device 120 to a communication state. The receiving unit 124 detects the i-th transmission UW that is the same as the i-th reception UW based on the i-th reception UW, and receives the i-th radio frame including the i-th reception UW.

[0182] <Example of wireless communication system operation> Next, an operation example of the wireless communication system 400 according to the third embodiment will be described with reference to Fig. 13. Fig. 13 is a diagram showing an operation example of the wireless communication system according to the third embodiment. Fig. 13 corresponds to Fig. 8, and steps performing the same operations as those shown in Fig. 8 are given the same reference numerals. In Fig. 13, operations described with the same reference numerals as those in Fig. 8 are the same as those in the second embodiment, and therefore will be omitted as appropriate. Fig. 13 is executed after the wireless communication devices 110 and 120 are started up.

[0183] In the standby state, the generating unit 32 generates a transmission standby UW that can be used as the first transmission UW based on the transmitting station operation time information, and updates the transmission standby UW (step S11). In the standby state, step S11 is repeatedly executed periodically at a predetermined period of time.

[0184] In the standby state, the generating unit 122 generates a reception standby UW based on the receiving station operation time information, a first candidate UW based on the one-cycle previous time information, and a second candidate UW based on the one-cycle later time information, and updates the reception standby UW, the first candidate UW, and the second candidate UW (step S31). In the standby state, step S31 is executed periodically and repeatedly at a predetermined cycle time.

[0185] At the timing of generating a receiving standby UW, the reference sequence output unit 1221 calculates one cycle ago time information indicating the operating time information one cycle ago from the current time, and one cycle later time information indicating the operating time information one cycle later from the current time.

[0186] The reference sequence output unit 1221 inputs the receiving station operation time information to the shift register 51 of the random number reference sequence generation circuit 50, and outputs the first random number reference sequence for the reception standby UW. The random number output unit 1222 inputs the first random number reference sequence for the reception standby UW, and outputs the first output value for the reception standby UW based on the random number table T1. The conversion sequence output unit 1223 outputs the first GOLD sequence based on the first output value for the reception standby UW to the receiving unit 124 as the reception standby UW. The conversion sequence output unit 1223 stores the reception standby UW in the memory unit 121.

[0187] The reference sequence output unit 1221 inputs the one-cycle previous time information to the shift register 51 of the random number reference sequence generation circuit 50, and outputs the first random number reference sequence for the first candidate UW. The random number output unit 1222 inputs the first random number reference sequence for the first candidate UW, and outputs the first output value for the first candidate UW based on the random number table T1. The converted sequence output unit 1223 outputs the first GOLD sequence based on the first output value for the first candidate UW to the receiving unit 124 as the first candidate UW. The converted sequence output unit 1223 stores the first candidate UW in the memory unit 121.

[0188] The reference sequence output unit 1221 inputs the one-cycle later time information to the shift register 51 of the random reference sequence generation circuit 50, and outputs the first random reference sequence for the second candidate UW. The random number output unit 1222 inputs the first random reference sequence for the second candidate UW, and outputs the first output value for the second candidate UW based on the random number table T1. The converted sequence output unit 1223 outputs the first GOLD sequence based on the first output value for the second candidate UW to the receiving unit 124 as the second candidate UW. The converted sequence output unit 1223 stores the second candidate UW in the memory unit 121.

[0189] When the transmitting unit 111 receives the data to be transmitted to the wireless communication device 40, it transitions the wireless communication device 30 to a communication state, and the wireless communication device 30 transitions to a communication state (step S13). The transmitting unit 111 transmits a first radio frame to the wireless communication device 120, the first radio frame including the first transmission UW, the transmitting station operation time information used to generate the first transmission UW, and the transmission data for the first radio frame (step S32).

[0190] The transmitter 111 acquires from the generator 32 the transmitting station operation time information used to generate the transmission standby UW generated before transitioning to the communication state. The transmitter 111 uses the transmission standby UW as the first transmission UW, and sets the first transmission UW and the transmitting station operation time information acquired from the generator 32 in the control header of the first wireless frame. The transmitter 111 generates a first wireless frame including the first transmission UW, the transmitting station operation time information used to generate the first transmission UW, and transmission data for the first wireless frame, and transmits the wireless frame to the wireless communication device 120.

[0191] When communication is started, the receiving unit 124 receives the first wireless frame based on the reception standby UW, the first candidate UW, and the second candidate UW (step S33). The receiving unit 124 uses the reception waiting UW as the first reception UW, and detects the first transmission UW based on the first reception UW, the first candidate UW, and the second candidate UW. The receiving unit 124 receives a radio frame including a transmission UW that is the same as any of the first reception UW, the first candidate UW, and the second candidate UW as the first radio frame. The receiving unit 124 obtains the transmitting station operation time information used to generate the first transmission UW from the control header of the first radio frame, and transmits the obtained transmitting station operation time information to the generating unit 122.

[0192] When the receiver 124 detects the first transmission UW, it transitions the wireless communication device 120 to a communication state (step S16). The generation unit 32 generates a second transmission UW based on the first transmission UW (step S17). Step S17 is executed after the transmission unit 34 transmits the first wireless frame to the wireless communication device 40 and before the generation of the second wireless frame.

[0193] The generation unit 122 generates a second received UW based on the transmitting station operation time information acquired from the first radio frame, the first received UW, the first candidate UW, and the second candidate UW (step S34).

[0194] The reference sequence output unit 1221 acquires the transmitting station operation time information included in the control header of the first radio frame from the receiving unit 124. The reference sequence output unit 1221 identifies a receiving UW that is the same as a transmitting UW based on the acquired transmitting station operation time information from among the first receiving UW, the first candidate UW, and the second candidate UW. The reference sequence output unit 1221 inputs the identified receiving UW to the shift register 51 of the random number reference sequence generating circuit 50. The reference sequence output unit 1221 shifts the shift register 51 once to generate a second random number reference sequence, and outputs the second random number reference sequence to the random number output unit 1222. After outputting the second random number reference sequence, the reference sequence output unit 1221 holds each value of the taps 52-1 to 52-N of the shift register 51.

[0195] The random number output unit 1222 receives the second random number reference sequence and outputs a second output value based on the random number table T1. The converted sequence output unit 1223 outputs the second GOLD sequence based on the second output value to the receiving unit 124 as the second received UW.

[0196] The transmitter 111 transmits a second wireless frame including a second transmission UW and transmission data to the wireless communication device 40 (step S19). Based on the second received UW, the receiving unit 124 detects a second transmitted UW that is identical to the second received UW, and receives a second wireless frame including a second transmitted UW that is identical to the second received UW (step S20).

[0197] After that, the wireless communication system 400 repeatedly executes steps S17 to S20 until the communication ends. When the communication ends, each of the wireless communication devices 110 and 120 transitions to a standby state and repeatedly executes steps S11 and S31 until the next communication starts.

[0198] The operations in steps S17 to S20 can be generalized and described as follows. The generation unit 32 generates the i-th transmission UW based on the (i-1)-th transmission UW (step S17). Step S17 is executed after the transmission unit 111 transmits the (i-1)-th wireless frame to the wireless communication device 40 and before generating the i-th wireless frame.

[0199] The generation unit 122 generates the i-th received UW based on the (i-1)-th received UW (step S18). Step S18 is executed before the reception unit 124 detects the (i-1)-th transmitted UW and the i-th wireless frame is transmitted from the wireless communication device 110. Note that the generation unit 122 generates the i-th received UW that is the same as the i-th transmitted UW to generate the second received UW that is the same as the second transmitted UW based on the transmitting station operation time information acquired from the first wireless frame.

[0200] The transmitter 111 transmits the i-th wireless frame including the i-th transmission UW and the transmission data to the wireless communication device 120 (step S19). Based on the i-th received UW, the receiving unit 124 detects the i-th transmitted UW that is identical to the i-th received UW, and receives the i-th wireless frame that includes the i-th transmitted UW that is identical to the i-th received UW (step S20).

[0201] As described above, even if the second embodiment is changed to the third embodiment, the same effect as the second embodiment can be obtained. Also, in this embodiment, the wireless communication device 120 generates a reception standby UW, a first candidate UW, and a second candidate UW at each predetermined periodic time. Therefore, even if there is an error between the operation time of the wireless communication device 110 and the operation time of the wireless communication device 120 and a reception UW that is the same as the transmission UW cannot be generated, the wireless communication device 110 and the wireless communication device 120 can communicate normally.

[0202] Furthermore, in this embodiment, wireless communication device 110 transmits the first wireless frame including the transmitting station operation time information used to generate the first transmitting UW to wireless communication device 120. Therefore, wireless communication device 120 can generate a receiving UW that is the same as the transmitting UW for the second and subsequent wireless frames without generating multiple receiving UWs. Therefore, according to wireless communication system 400 of the fourth embodiment, even if there is a large error between the transmitting station operation time information and the receiving station operation time information, normal communication can be performed while suppressing the communication contents from being intercepted.

[0203] (Other embodiments) The wireless communication devices 10, 20, 30, 40, 110, and 120 (hereinafter referred to as wireless communication device 10, etc.) according to the above-described embodiments may have the following hardware configuration. Fig. 14 is a block diagram illustrating an example of the hardware configuration of a computer (information processing device) capable of realizing the wireless device according to each embodiment.

[0204] 14, the wireless communication device 10 includes antennas 1201-1 to 1201-L (L: an integer equal to or greater than 1), a network interface 1202, a processor 1203, and a memory 1204. The antennas 1201-1 to 1201-L and the network interface 1202 are used to communicate with other wireless communication devices. The network interface 1202 may include, for example, a network interface card (NIC) that complies with the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series, IEEE 802.3 series, or the like.

[0205] The processor 1203 reads out and executes software (computer programs) from the memory 1204 to perform the processing of the wireless communication device 10 and the like described using the flowcharts in the above-mentioned embodiments. The processor 1203 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). The processor 1203 may include multiple processors.

[0206] The memory 1204 is configured by a combination of volatile memory and non-volatile memory. The memory 1204 may include storage located away from the processor 1203. In this case, the processor 1203 may access the memory 1204 via an I / O (Input / Output) interface (not shown).

[0207] 14, the memory 1204 is used to store software modules. The processor 1203 reads out and executes the software modules from the memory 1204 to perform the processing of the wireless communication device 10 and the like described in the above-mentioned embodiment.

[0208] As described with reference to FIG. 14, each of the processors included in the wireless communication device 10 etc. executes one or more programs including a set of instructions for causing a computer to execute the algorithm described with reference to the drawing.

[0209] In the above example, the program can be stored and provided to the computer using various types of non-transitory computer readable media. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives) and magneto-optical recording media (e.g., magneto-optical disks). Further, examples of the non-transitory computer readable media include CD-ROM (Read Only Memory), CD-R, and CD-R / W. Further, examples of the non-transitory computer readable media include semiconductor memory. The semiconductor memory includes, for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, and RAM (Random Access Memory). The program may also be provided to the computer by various types of transitory computer readable media. Examples of the transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire or an optical fiber, or via a wireless communication path.

[0210] In addition, the present disclosure is not limited to the above-described embodiment, and can be appropriately modified without departing from the spirit and scope of the present disclosure. In addition, the present disclosure may be implemented by appropriately combining the respective embodiments.

[0211] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) 1. A wireless communication device, comprising: a generating unit that generates a first unique word based on operation time information of the wireless communication device before communication with another wireless communication device is started, and generates an i-th unique word based on an (i-1)-th unique word (i: an integer equal to or greater than 2) for each wireless frame when the communication is started; a transmitter configured to transmit a first radio frame including the first unique word and the i-th radio frame including the i-th unique word to the other radio communication device. (Appendix 2) The generation unit is a reference sequence output unit that outputs a first reference sequence, which is a pseudo-random number sequence, based on the operation time information, and outputs an i-th reference sequence for each radio frame based on an (i-1)-th reference sequence; a converted sequence output unit that outputs a first converted sequence which is a pseudo-random number sequence, and outputs an i-th converted sequence which is a pseudo-random number sequence for each radio frame, 2. The wireless communication device according to claim 1, wherein the converted sequence output unit outputs the first converted sequence based on the first reference sequence as the first unique word, and outputs the i converted sequence based on the i reference sequence as the i unique word. (Appendix 3) The generation unit is A random number output unit that outputs the first output value and the i output value based on a random number table, the random number output unit outputs the first output value based on the first reference sequence, and outputs the i-th output value based on the i-th reference sequence for each radio frame; 3. The wireless communication device according to claim 2, wherein the converted sequence output unit outputs the first converted sequence based on the first output value as the first unique word, and outputs the i converted sequence based on the i output value as the i unique word. (Appendix 4) The reference sequence output unit a shift register including a plurality of taps, the shift register inputting a plurality of bits constituting the operation time information to the plurality of taps; a feedback tap that designates a tap among the plurality of taps whose tap value is fed back to the shift register; an arithmetic circuit that performs an exclusive OR operation on the value output from the tap that is fed back and feeds back the calculated value to the shift register; The wireless communication device according to claim 2 or 3, wherein the reference sequence output unit shifts the shift register a predetermined number of times and outputs the first reference sequence based on values ​​output from the multiple taps. (Appendix 5) 5. The wireless communication device according to claim 1, wherein the transmission unit transmits the first wireless frame including the operating time information and the first unique word. (Appendix 6) 6. The wireless communication device according to claim 1, wherein the generation unit periodically updates the first unique word before the communication is started. (Appendix 7) 1. A wireless communication device, comprising: a generation unit that generates a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device, the second operating time information corresponding to first operating time information used by the other wireless communication device to generate a first transmission unique word, before communication with the other wireless communication device is started; a receiving unit that receives a radio frame including the first transmission unique word based on the first reception unique word, the generation unit generates, when the communication is started, for each wireless frame, an i-th reception unique word corresponding to an i-th transmission unique word generated by the other wireless communication device, based on an (i-1)-th reception unique word (i: an integer equal to or greater than 2); The wireless communication device, wherein the receiving unit receives a wireless frame including the ith transmission unique word based on the ith reception unique word. (Appendix 8) The generation unit is a reference sequence output unit that outputs a first reception reference sequence, which is a pseudo-random number sequence corresponding to a first transmission reference sequence generated by the other wireless communication device, based on the second operation time information, and outputs an i-th reception reference sequence corresponding to the i-th transmission reference sequence generated by the other wireless communication device, based on the (i-1)-th reception reference sequence for each wireless frame; a converted sequence output unit that outputs a first converted sequence for reception corresponding to a first converted sequence for transmission generated by the other wireless communication device, and outputs an ith converted sequence for reception corresponding to an ith converted sequence for transmission generated by the other wireless communication device for each wireless frame, The wireless communication device described in claim 7, wherein the conversion sequence output unit outputs the first reception conversion sequence based on the first reception reference sequence as the first reception unique word, and outputs the i reception conversion sequence based on the i reception reference sequence as the i reception unique word. (Appendix 9) The generation unit is a random number output unit that outputs a first reception output value corresponding to a first transmission output value output by the other wireless communication device based on a random number table, and outputs an i-th reception output value corresponding to an i-th transmission output value output by the other wireless communication device for each wireless frame, the random number output unit outputs the first reception output value based on the first reception reference sequence, and outputs the i-th reception output value based on the i-th reception reference sequence; The wireless communication device described in claim 8, wherein the conversion sequence output unit outputs the first reception conversion sequence based on the first reception output value as the first reception unique word, and outputs the i reception conversion sequence based on the i reception output value as the i reception unique word. (Appendix 10) The reference sequence output unit a shift register including a plurality of taps, the shift register inputting a plurality of bits constituting the second operating time information to the plurality of taps; a feedback tap that designates a tap among the plurality of taps whose tap value is fed back to the shift register; an arithmetic circuit that calculates an exclusive OR on the fed-back tap value and feeds back the calculated value to the shift register; 10. The wireless communication device according to claim 8, wherein the reference sequence output unit shifts the shift register a predetermined number of times and outputs the first received reference sequence based on values ​​output from the multiple taps. (Appendix 11) the generation unit periodically updates the first received unique word at a predetermined periodic time before the communication is started, and periodically generates a first candidate unique word based on third operating time information corresponding to a time before the periodic time from the time indicated by the second operating time information, and a second candidate unique word based on fourth operating time information corresponding to a time after the periodic time from the time indicated by the second operating time information; 11. The wireless communication device according to any one of appendixes 7 to 10, wherein the receiving unit receives a wireless frame including any one of the first received unique word, the first candidate unique word, and the second candidate unique word. (Appendix 12) when the receiving unit receives a wireless frame including any one of the first received unique word, the first candidate unique word, and the second candidate unique word, it acquires operating time information included in the received wireless frame as the first operating time information; The wireless communication device described in Appendix 11, wherein the generation unit identifies a received unique word that corresponds to the first transmission unique word from among the first received unique word, the first candidate unique word, and the second candidate unique word based on the first operating time information, and generates a second received unique word based on the identified received unique word. (Appendix 13) 13. The wireless communication device according to claim 12, wherein the generation unit corrects the operating time of the wireless communication device based on the first operating time information. (Appendix 14) 1. A wireless communication method performed by a wireless communication device, comprising: generating a first unique word based on operation time information of the wireless communication device before communication with another wireless communication device is started; When the communication is started, a first wireless frame including the first unique word is transmitted to the other wireless communication device; generating an ith unique word for each radio frame based on an (i-1)th unique word (i: an integer equal to or greater than 2); a wireless communication method for transmitting the i-th wireless frame including the i-th unique word to the other wireless communication device; (Appendix 15) 1. A wireless communication method performed by a wireless communication device, comprising: before communication with another wireless communication device is started, generating a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device, the second operating time information corresponding to first operating time information used by the other wireless communication device to generate a first transmission unique word; receiving a wireless frame including the first transmission unique word based on the first reception unique word when the communication is started; generating an ith reception unique word corresponding to an ith transmission unique word generated by the other wireless communication device, based on an (i-1)th reception unique word (i: an integer equal to or greater than 2) for each wireless frame; receiving a radio frame including the i-th transmission unique word based on the i-th reception unique word; (Appendix 16) A wireless communication program executed by a wireless communication device, generating a first unique word based on operation time information of the wireless communication device before communication with another wireless communication device is started; When the communication is started, a first wireless frame including the first unique word is transmitted to the other wireless communication device; generating an ith unique word for each radio frame based on an (i-1)th unique word (i: an integer equal to or greater than 2); a wireless communication device that transmits the i-th wireless frame including the i-th unique word to the other wireless communication device; (Appendix 17) A wireless communication program to be executed by a wireless communication device, 1. A wireless communication method performed by a wireless communication device, comprising: before communication with another wireless communication device is started, generating a first reception unique word corresponding to the first transmission unique word based on second operating time information of the wireless communication device, the second operating time information corresponding to first operating time information used by the other wireless communication device to generate a first transmission unique word; receiving a wireless frame including the first transmission unique word based on the first reception unique word when the communication is started; generating an ith reception unique word corresponding to an ith transmission unique word generated by the other wireless communication device, based on an (i-1)th reception unique word (i: an integer equal to or greater than 2) for each wireless frame; receiving a wireless frame including the i-th transmission unique word based on the i-th reception unique word. (Appendix 18) A first wireless communication device and a second wireless communication device, The first wireless communication device is generating a first transmission unique word based on first operation time information of the first wireless communication device before communication with the second wireless communication device is started, and when the communication is started, generating an i-th transmission unique word for each wireless frame based on an (i-1)-th transmission unique word (i: an integer equal to or greater than 2); Transmitting a first wireless frame including the first transmission unique word to the second wireless communication device, and transmitting the i wireless frame including the i transmission unique word to the second wireless communication device; The second wireless communication device is before the communication is started, a first reception unique word corresponding to the first transmission unique word is generated based on second operating time information of the second wireless communication device, the second operating time information corresponding to the first operating time information, and when the communication is started, an ith reception unique word corresponding to the ith transmission unique word is generated for each wireless frame based on an (i-1)th reception unique word; a first wireless frame received based on the first received unique word, and a i-th wireless frame received based on the i-th received unique word; (Appendix 19) The first wireless communication device is transmitting the first wireless frame including the first operating time information and the first transmission unique word; The second wireless communication device is before the communication is started, periodically updating the first received unique word at a predetermined periodic time, and periodically generating a first candidate unique word based on third operating time information corresponding to a time before the periodic time from the time indicated by the second operating time information, and a second candidate unique word based on fourth operating time information corresponding to a time after the periodic time from the time indicated by the second operating time information; 19. The wireless communication system of claim 18, further comprising: receiving a wireless frame including any one of the first received unique word, the first candidate unique word, and the second candidate unique word. [Explanation of symbols]

[0212] 10, 20, 30, 40, 110, 120 Wireless communication device 11, 21, 32, 42, 122 generation section 12, 34, 111 Transmitter 22, 44, 124 Receiver 31, 41, 121 storage section 321, 421, 1221 Reference series output section 322, 422, 1222 Random number output section 323, 423, 1223 conversion sequence output section 50 Random number reference sequence generator 51, 81, 83 Shift Registers 52-1~52-N, 82-1~82-5, 84-1~84-5 Tap 53 Return Tap 55-1~55-N AND circuit 56-1~56-(N-1), 85-1~85-3, 86-1, 87 XOR circuit 80 Transformation sequence generator 100, 200, 400 Wireless communication system 1201-1~1201-L Antenna 1202 Network Interface 1203 Processor 1204 Memory

Claims

1. 1. A wireless communication device, comprising: a generation unit that forms a reference sequence based on reception operation time information, acquires a random number value based on the formed reference sequence, and generates a conversion sequence as a reception unique word based on the acquired random number value; a receiving unit that receives a wireless frame including a transmission unique word transmitted from another wireless communication device based on the generated reception unique word, The generation unit is before communication with the other wireless communication device is started, a first reference sequence is formed based on first reception operation time information corresponding to first transmission operation time information used by the other wireless communication device to generate a first transmission unique word, a first random value is obtained based on the first reference sequence, and a first conversion sequence is periodically generated as a first reception unique word at a predetermined periodic time based on the obtained first random value, and a first front side candidate unique word is periodically generated based on first front side reception operation time information corresponding to a time before the periodic time from the time indicated by the first reception operation time information, and a first rear side candidate unique word is periodically generated based on first rear side reception operation time information corresponding to a time after the periodic time from the time indicated by the first reception operation time information, when communication with the other wireless communication device is started, for each wireless frame, form an ith reference sequence based on an (i-1)th reference sequence (i: an integer of 2 or more), obtain an ith random value based on the ith reference sequence, and generate an ith conversion sequence as an ith received unique word based on the obtained ith random value; A wireless communication device, wherein the receiving unit receives a first wireless frame including any one of the first received unique word, the first front side candidate unique word, and the first rear side candidate unique word.

2. when the receiving unit receives a first radio frame including any one of the first receiving unique word, the first front side candidate unique word, and the first rear side candidate unique word, it acquires operation time information included in the received first radio frame as the first transmitting operation time information; The wireless communication device of claim 1, wherein the generation unit identifies a receiving unique word from among the first receiving unique word, the first front-side candidate unique word, and the first rear-side candidate unique word that corresponds to the first transmitting unique word and is used to receive the first wireless frame based on the first transmitting operation time information.

3. 1. A wireless communication method performed by a wireless communication device, comprising: forming a reference sequence based on the operation time information, acquiring a random value based on the formed reference sequence, and generating a conversion sequence as a reception unique word based on the acquired random value; receiving a wireless frame including a transmission unique word transmitted from another wireless communication device based on the generated reception unique word; Including, generating the received unique word comprises: before communication with the other wireless communication device is started, forming a first reference sequence based on first receiving operation time information corresponding to first transmitting operation time information used by the other wireless communication device to generate a first transmission unique word, acquiring a first random value based on the first reference sequence, and periodically generating a first converted sequence as a first receiving unique word at a predetermined periodic time based on the acquired first random value, and periodically generating a first front-side candidate unique word based on first front-side receiving operation time information corresponding to a time before the periodic time from the time indicated by the first receiving operation time information, and a first back-side candidate unique word based on first back-side receiving operation time information corresponding to a time after the periodic time from the time indicated by the first receiving operation time information; when communication with the other wireless communication device is started, forming an ith reference sequence for each wireless frame based on an (i-1)th reference sequence (i: an integer equal to or greater than 2), obtaining an ith random value based on the ith reference sequence, and generating an ith conversion sequence as an ith received unique word based on the obtained ith random value; Including, The wireless communication method, wherein the receiving includes receiving a first wireless frame including any one of the first received unique word, the first front side candidate unique word, and the first rear side candidate unique word.

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