JP2017199963A - Wireless communication system and wireless device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform communication between wireless devices, under communication conditions set adaptively according to communication environment between wireless devices.SOLUTION: A terminal 14 transmits a test signal to a base station 12 under first communication conditions (e.g., communication channel f1, transmission rate M1). Upon receiving the test signal, the base station 12 transmits ACK to the terminal 14 under first communication conditions. When not receiving the ACK from the base station 12 within a predetermined time after transmission of the test signal, the terminal 14 retransmits the test signal to the base station 12 under second communication conditions (e.g., communication channel f2, transmission rate M2) different from the first communication conditions. When the ACK is received by the terminal 14 within a predetermined time after the test signal was transmitted under second communication conditions, communication conditions between the base station 12 and the terminal 14 are set to second communication conditions.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wireless communication system and a wireless device.

  Conventionally, wireless communication is used as a method for realizing communication between apparatuses. Wireless communication eliminates the need for cable laying and management maintenance required when wired communication is used, and can reduce initial costs and running costs. Therefore, a wireless communication system having a plurality of wireless devices and performing wireless communication between wireless devices is used (for example, Patent Document 1).

  When a specific frequency band is shared by various wireless communication systems, communication quality between wireless devices may be reduced due to frequency interference between the wireless communication systems. If the communication quality deteriorates too much, communication may not be possible between wireless devices.

  As a countermeasure when the communication quality between the wireless devices deteriorates, it is conceivable to change the communication conditions between the wireless devices. For example, it is conceivable to change the communication channel (center frequency) or transmission rate between wireless devices. The change of the transmission rate is realized by changing the bandwidth or the modulation method, for example.

  Communication conditions between wireless devices need to be shared between two wireless devices that perform communication. Therefore, conventionally, in order to share communication conditions between wireless devices, a process called negotiation is performed using a control channel provided between wireless devices (communication conditions that enable communication with a general wireless device). It was done.

JP 2006-100932 A

  When communication quality between wireless devices is poor and communication using a control channel is not possible, there is a problem that communication conditions cannot be shared between wireless devices. For example, if information indicating the communication condition cannot be transmitted from one wireless device to the other wireless device, the communication condition cannot be shared between the wireless devices. In addition, when information indicating communication conditions can be transmitted from one wireless device to the other wireless device, but one wireless device cannot receive an acknowledgment message from the other wireless device, the communication conditions between the two wireless devices May occur, and communication may not be performed at all.

  Further, since the communication for negotiation is performed using the control channel, the communication condition is generally different from the communication condition shared between wireless devices. Therefore, it can be pointed out that there is no guarantee that the communication condition shared in the negotiation becomes an appropriate communication condition between the wireless devices.

  An object of the present invention is to perform communication between wireless devices under communication conditions adaptively set according to the communication environment between the wireless devices.

  The present invention is a wireless communication system including a first wireless device and a second wireless device connected so as to be capable of wireless communication, and the first wireless device receives a communication test signal from the second wireless device. A reception confirmation signal transmitting unit that transmits a reception confirmation signal to the second wireless device, wherein the second wireless device includes a communication condition setting unit that sets a communication condition for the first wireless device, and a first communication condition. The communication test signal is transmitted to the first wireless device, and the reception confirmation signal is not received from the first wireless device within a predetermined time after the communication test signal is transmitted under the first communication condition. A communication test signal transmitter configured to transmit the communication test signal to the first wireless device under a second communication condition different from the first communication condition, wherein the second wireless device includes the first communication condition. To send the communication test signal. When the reception confirmation signal is received from the first wireless device within a predetermined time after the first wireless device and the second wireless device start communication under the first communication condition, the second wireless device When the reception confirmation signal is received from the first wireless device within a predetermined time after transmitting the communication test signal under the second communication condition, the first wireless device and the second wireless device Communication is started under communication conditions.

  Preferably, the second wireless device further includes a communication quality detection unit that detects communication quality between the first wireless device and the second wireless device, and the first wireless device and the second wireless device. Is communicating under the first communication condition, and when the detected communication quality falls below a predetermined level, the communication test signal transmitting unit transmits the communication test signal under the second communication condition. It transmits to 1 radio | wireless apparatus, It is characterized by the above-mentioned.

  Preferably, the first communication condition and the second communication condition include a communication channel and a transmission rate.

  The present invention also relates to a wireless device connected to another wireless device so as to be able to perform wireless communication, a communication condition setting unit for setting communication conditions for the other wireless device, and a communication test signal under the first communication condition. The first communication is performed when the reception confirmation signal is not received from the other wireless device within a predetermined time after being transmitted to the other wireless device and further transmitting the communication test signal under the first communication condition. A communication test signal transmitter for transmitting the communication test signal to the other wireless device under a second communication condition different from the condition, and within a predetermined time after transmitting the communication test signal under the first communication condition When the reception confirmation signal is received from the other wireless device, communication with the other wireless device is started under the first communication condition, and the communication test signal is transmitted under the second communication condition. The other wireless device within a predetermined time When receiving the acknowledgment signal, starts communication by the second communication condition between said another wireless device, and wherein the.

  ADVANTAGE OF THE INVENTION According to this invention, the communication between the said radio | wireless apparatuses can be performed on the communication conditions set adaptively according to the communication environment between radio | wireless apparatuses.

1 is a schematic configuration diagram of a wireless communication system according to the present embodiment. It is a conceptual diagram which shows the example in which the communication conditions between a base station and a terminal are set. It is a conceptual diagram which shows the other example in which the communication conditions between a base station and a terminal are set. It is a flowchart which shows the flow of a process of the radio | wireless communications system which concerns on this embodiment.

<Configuration outline of wireless communication system>
Hereinafter, embodiments of the present invention will be described. FIG. 1 is a schematic configuration diagram of a wireless communication system 10 according to the present embodiment. The wireless communication system 10 includes a base station 12 as a first wireless device, a terminal 14 as a second wireless device, and a PC (Personal Computer) 16.

  The base station 12 is a wireless device that performs wireless communication with one or a plurality of terminals 14. The base station 12 is a wireless communication unit, for example, but is not limited thereto. The terminal 14 is a wireless device connected to the base station 12 so that wireless communication is possible. The terminal 14 is, for example, a remote monitoring terminal (for example, one that detects opening / closing of a door and transmits it to the base station 12), but is not limited thereto. The wireless communication method between the base station 12 and the terminal 14 may be, for example, specific low power wireless communication, wireless communication using a mobile phone line such as LTE (Long Time Evolution), or wireless LAN communication. .

  The PC 16 is communicably connected to the base station 12 by wired communication or wireless communication. For example, the base station 12 and the PC 16 are connected with an RS232C cable. The PC 16 is used by an administrator (user) of the wireless communication system 10 and displays or stores data transmitted from the terminal 14, for example.

  Hereinafter, details of the configuration of the base station 12 will be described.

  The storage unit 20 includes, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory). The storage unit 20 stores a program for operating each unit of the base station 12. The storage unit 20 also stores information indicating communication conditions with the terminal 14. When a plurality of terminals 14 are wirelessly connected to the base station 12, a plurality of communication conditions are stored for each terminal. Various conditions may be included as communication conditions. In the present embodiment, the communication conditions include a communication channel (center frequency used for data transmission / reception) and a transmission rate (data transmission / reception amount per unit time). As will be described later, the transmission rate is a modulation method (modulation method) applied to data transmitted / received between the base station 12 and the terminal 14 or a frequency range used for data transmission / reception. It is determined according to a certain bandwidth.

  The control unit 22 is configured by, for example, a microcontroller and controls each unit of the base station 12 according to a program stored in the storage unit 20.

  The transmission frame processing unit 24 performs processing for converting a frame of data to be transmitted from the base station 12 to the terminal 14 into a frame suitable for wireless communication between the base station 12 and the terminal 14. As data to be transmitted from the base station 12 to the terminal 14, for example, the ACK for notifying the terminal 14 that the base station 12 has received a test signal (described later) from the terminal 14, or for controlling the terminal 14 There is data.

  The modulation unit 26 performs a process of modulating the data output from the transmission frame processing unit 24. The modulation unit 26 can switch the modulation method and bandwidth for modulating data in accordance with an instruction from the control unit 22. Note that the modulation unit 26 may have a digital filter, and the bandwidth may be controlled by the digital filter. By switching the modulation method or the bandwidth, the transmission rate when data is transmitted from the base station 12 to the terminal 14 is changed. That is, the modulation unit 26 constitutes a communication condition setting unit on the base station 12 side. The modulation unit 26 can modulate data by various modulation methods. For example, FSK (Frequency Shift Keying), PSK (Phase Shift Keying), ASK (Amplitude Shift Keying), multilevel QAM (Quadrature Amplitude Modulation), OFDM (Orthogonal Frequency Division Multiplexing), etc. can be used.

  The D / A processing unit 28 performs processing for converting the data modulated by the modulation unit 26 from a digital signal to an analog signal.

  The transmission RF unit 30 up-converts the analog baseband signal converted by the D / A processing unit 28 and converts it to a high-frequency signal. Data is transmitted from the antenna 34 at the frequency of the high-frequency signal. The transmission RF unit 30 can switch the center frequency of the converted high-frequency signal in accordance with an instruction from the control unit 22. Thereby, the communication channel when data is transmitted from the base station 12 to the terminal 14 is changed. That is, the transmission RF unit 30 constitutes a communication condition setting unit on the base station 12 side. Further, the transmission RF unit 30 performs amplification processing for amplifying the converted high-frequency signal.

  The RF switch 32 is a switch that switches the path of the high-frequency signal. The RF switch 32 switches between supplying a high-frequency signal from the transmission RF unit 30 to the antenna 34 or supplying a high-frequency signal from the antenna 34 to the reception RF unit 36 in accordance with an instruction from the control unit 22.

  The antenna 34 radiates (transmits) a high-frequency signal from the RF switch 32 into the air as a radio wave. In addition, radio waves are received from the air, converted into high frequency signals, and supplied to the RF switch 32.

  The reception RF unit 36 performs amplification processing for amplifying the high-frequency signal from the RF switch 32, down-converts the amplified high-frequency signal, and converts it into a baseband signal.

  The A / D processing unit 38 performs processing for converting the baseband signal converted by the reception RF unit 36 from an analog signal to a digital signal.

  The channel filter group 40 includes a plurality of channel filters. The channel filter is a band pass filter, and is a filter that passes a signal having a frequency within a predetermined range. The frequency ranges that each channel filter passes are different. The frequency range that each channel filter passes corresponds to each communication channel that can be set between the base station 12 and the terminal 14. In FIG. 1, the channel filter group 40 includes four channel filters, but the number of channel filters included in the channel filter group 40 is not limited thereto.

  The demodulating unit group 42 includes a plurality of demodulating units. Each demodulator included in the demodulator group 42 is provided corresponding to each channel filter included in the channel filter group 40. Each demodulator receives data that has passed through the channel filter at the transmission rate set by the controller 22. That is, the demodulator demodulates the data in a manner according to the instruction from the controller 22. Specifically, the demodulator demodulates data by a method according to the modulation method and bandwidth set in the modulation unit 54 (described later) of the terminal 14.

  The reception frame processing unit 44 performs processing for converting the frame of data demodulated by each demodulation unit into a frame suitable for communication between the base station 12 and the PC 16.

  Of the components included in the base station 12, the transmission frame processing unit 24, the modulation unit 26, the D / A processing unit 28, the transmission RF unit 30, the RF switch 32, the reception RF unit 36, and the A / D processing unit 38. The functions of the channel filter group 40, the demodulation unit group 42, and the reception frame processing unit 44 can be realized by using hardware such as a processor, for example. Further, it may be realized by cooperation of hardware such as a processor and software for operating the processor.

  As described above, the base station 12 performs modulation processing of data to be transmitted to the terminal 14 and conversion processing to a high frequency signal and transmits the radio wave from the antenna 34 as a radio wave. Also, conversion processing and demodulation processing of data received from the terminal 14 into a baseband signal are performed. As described above, the base station can communicate with the terminal 14 using a plurality of communication channels and a plurality of transmission rates. Further, the base station 12 is provided with a plurality of channel filters and demodulation units, so that a plurality of signals received by different communication channels and different transmission rates can be processed simultaneously.

  Details of the configuration of the terminal 14 will be described below. The terminal 14 has substantially the same configuration as the base station 12. A detailed description of the same components as the base station 12 is omitted.

  The modulation unit 54 performs processing for modulating data to be transmitted from the terminal 14 to the base station 12. Data to be transmitted from the terminal 14 to the base station 12 includes a test signal for determining communication conditions between the base station 12 and the terminal 14. Alternatively, for example, when the terminal 14 is a remote monitoring terminal, there is a detection signal (for example, a detection signal indicating an open state of a door) detected by a detection unit (not shown) included in the terminal 14. The modulation unit 54 can switch the modulation scheme and bandwidth for modulating the data to be transmitted in accordance with an instruction from the control unit 52. By switching the modulation method or bandwidth, the transmission rate when data is transmitted from the terminal 14 to the base station 12 is changed. That is, the modulation unit 54 constitutes a communication condition setting unit on the terminal 14 side.

  The data modulated by the modulation unit 54 is converted into an analog signal by the D / A processing unit 56. Further, the analog baseband signal is up-converted by the transmission RF unit 58 and converted into a high-frequency signal. The transmission RF unit 58 can switch the center frequency of the converted high-frequency signal in accordance with an instruction from the control unit 52. Thereby, the communication channel when data is transmitted from the terminal 14 to the base station 12 is changed. That is, the transmission RF unit 58 constitutes a communication condition setting unit on the terminal 14 side.

  The high frequency signal from the transmission RF unit 58 is transmitted from the antenna 62 via the RF switch 60.

  The high frequency signal received by the antenna 62 from the base station 12 is sent to the reception RF unit 64 via the RF switch 60. The high frequency signal is converted into a baseband signal by the reception RF unit 64, and further converted into a digital signal by the A / D conversion unit 66.

  The channel filter 68 passes a signal in the frequency range instructed from the control unit 52, and the demodulation unit 70 demodulates the data that has passed through the channel filter 68 in a method according to the instruction from the control unit 22.

  Desirably, the terminal 14 is provided with a received signal strength detector 72 as a communication quality detector. The reception signal strength detection unit 72 detects the strength of the reception signal received by the antenna 62 from the base station 12 and sends the detection signal to the control unit 52. The received signal strength detection unit 72 may constantly monitor the strength of the received signal or may detect it intermittently. As will be described later, the intensity of the received signal is used as a trigger for changing the communication condition between the base station 12 and the terminal 14.

  The outline of the configuration of the wireless communication system 10 is as described above. As described above, the terminal 14 can communicate with the base station 12 using a plurality of communication channels and a plurality of transmission rates. In the wireless communication system 10, prior to starting wireless communication between the base station 12 and the terminal 14, communication conditions are shared between both devices. In the wireless communication system 10, communication conditions are shared between the base station 12 and the terminal 14 without using a control channel that has been used conventionally. Hereinafter, the specific processing contents of communication condition sharing (setting) between the base station 12 and the terminal 14 will be described with reference to FIG. 1 and FIG. 2 and FIG. 3.

<Sharing of communication conditions between base station and terminal>
FIG. 2 is a conceptual diagram showing an example of the operation of both apparatuses when setting communication conditions between the base station 12 and the terminal 14. First, before starting communication with the base station 12, the terminal 14 transmits a test signal as a communication test signal to the base station 12 under predetermined communication conditions. The test signal may be stored in the storage unit 50 in advance.

  In the example of FIG. 2, transmission is performed using the communication channel f1 and the transmission rate M1. Specifically, the test signal is modulated by the modulation unit 26 with a modulation method and a bandwidth corresponding to the transmission rate M1, and the modulation signal is converted into a frequency corresponding to the communication channel f1 by the transmission RF unit 30 to be transmitted. It is transmitted from an antenna 62 as a test signal transmitter.

  The communication condition for transmitting the test signal first may be appropriately set by the user. For example, when it is desired to perform communication between the base station 12 and the terminal 14 as fast as possible, the highest transmission rate that can be set in the base station 12 and the terminal 14 may be set. Alternatively, since the transmission rate and the transmission distance are in an inversely proportional relationship, for example, when the terminal 14 is installed in a place far from the base station 12 and when it is desired to start communication reliably at an early stage, the base station 12 and The lowest transmission rate that can be set in the terminal 14 may be set.

  The test signal received by the antenna 34 of the base station 12 is sent to the control unit 22 through processing from the RF switch 32 to the reception frame processing unit 44. The control unit 22 outputs ACK as a reception confirmation signal, triggered by receiving the test signal. ACK is a signal for notifying the terminal 14 that the base station 12 has received the test signal. The ACK is transmitted from the antenna 34 serving as the reception confirmation signal transmission unit to the terminal 14 through the processing from the transmission frame processing unit 24 to the RF switch 32. Preferably, the base station 12 transmits ACK to the terminal 14 under the same communication condition as that when the test signal is transmitted from the terminal 14. That is, ACK is transmitted by communication channel f1 and transmission rate M1.

  Since the base station 12 can receive signals with a plurality of channels and a plurality of transmission rates, the base station 12 can set the channel and the transmission rate in advance, so that the test signal from the terminal 14 can be received. Communication conditions can be acquired.

  When the control unit 22 receives a test signal from the terminal 14, the control unit 22 associates the terminal 14 with a communication condition (communication channel f 1, transmission rate M 1) when the test signal is transmitted to the storage unit 20. Remember.

  When the terminal 14 receives an ACK from the base station 12, it means that communication is possible between the base station 12 and the terminal 14 under the communication conditions (communication channel f1, transmission rate M1). Accordingly, the communication condition between the base station 12 and the terminal 14 is set to the communication channel f1 and the transmission rate M1. Specifically, the control unit 52 of the terminal 14 stores the communication condition when the test signal is transmitted in the storage unit 50 as the communication condition with the base station 12. The control unit 22 of the base station 12 uses the communication condition stored in the storage unit 20 when the test signal is received as the communication condition with the terminal 14. Thereafter, communication is started between the base station 12 and the terminal 14 under the set communication conditions.

  FIG. 3 is a conceptual diagram illustrating another example of the operation of both apparatuses when setting communication conditions between the base station 12 and the terminal 14.

  In the example of FIG. 3, as in the example of FIG. 2, first, the terminal 14 sends a test signal to the base station 12 under a predetermined communication condition (communication channel f1, transmission rate M1) before starting communication with the base station 12. Send to. The base station 12 that has received the test signal transmits the ACK to the terminal 14 under the communication condition (communication channel f1, transmission rate M1), and stores the terminal 14 and the communication condition in association with each other in the storage unit 20.

  In the example of FIG. 3, it is assumed that the ACK from the base station 12 does not reach the terminal 14 because the communication environment between the base station 12 and the terminal 14 is bad. If the terminal 14 cannot receive ACK from the base station 12 within a predetermined time after transmitting the test signal, the terminal 14 changes the communication condition and transmits the test signal to the base station 12 again. In this example, the communication channel is changed, and the test signal is retransmitted at the communication channel f2 and the transmission rate M1.

  In this example, it is assumed that the test signal transmitted at the communication channel f2 and the transmission rate M1 does not reach the base station 12. Then, naturally, since the base station 12 does not return ACK, the terminal 14 changes the communication condition again and transmits a test signal to the base station 12. In this example, the transmission rate is changed, and the test signal is retransmitted at the communication channel f2 and the transmission rate M2.

  The base station 12 that has received the test signal transmitted at the communication channel f2 and the transmission rate M2 transmits an ACK to the terminal 14 under the communication condition (communication channel f2 and transmission rate M2), and performs communication associated with the terminal 14. Update the condition to the communication condition. When the terminal 14 receives an ACK from the base station 12, the communication condition between the base station 12 and the terminal 14 is set to the communication channel f2 and the transmission rate M2.

  The example of FIGS. 2 and 3 is an example in which communication conditions are set before the communication between the base station 12 and the terminal 14 is started. However, after the communication conditions are once set and communication is started, the above method is used. Communication condition change processing may be performed. For example, when communication is performed between the base station 12 and the terminal 14 in the communication channel f1 and the transmission rate M1, the received signal strength detected by the received signal strength detecting unit 72 is equal to or lower than a predetermined level. In this case, the terminal 14 transmits a test signal to the base station 12 under a communication condition (for example, communication channel f2, transmission rate M1) different from the current communication condition. Thereafter, the communication conditions between the base station 12 and the terminal 14 are changed by the same processing as in the example shown in FIG. 2 or FIG.

  As described above, according to the wireless communication system 10, communication conditions can be shared between the base station 12 and the terminal 14 without using a conventionally used control channel. According to the present embodiment, the base station 12 receives the test signal transmitted from the terminal 14 under the communication conditions actually used for communication, and the terminal 14 receives the ACK transmitted from the base station 12 under the same communication conditions. With the reception (that is, after confirming that communication is possible between the two devices under the same communication conditions), the communication conditions between the two devices are set. Therefore, it is possible to set communication conditions that allow reliable communication between the base station 12 and the terminal 14.

  Preferably, the communication condition can be changed based on the detection result of the communication quality by monitoring the communication quality between both devices. As a result, even when the communication quality deteriorates due to a change in the communication environment between the two devices, the communication conditions can be dynamically changed (improved).

  Hereinafter, the processing flow of the wireless communication system 10 will be described with reference to the flowchart shown in FIG.

  In step S10, the terminal 14 transmits a test signal to the base station 12 under the first communication condition (for example, communication channel f1, transmission rate M1).

  In step S <b> 12, the base station 12 determines whether a test signal has been received from the terminal 14. If a test signal has been received, the process proceeds to step S14. If a test signal has not been received, the process proceeds to step S20.

  In step S14, the base station 12 associates and stores the terminal 14 and the first communication condition while transmitting ACK to the terminal 14 under the first communication condition.

  In step S16, the terminal 14 determines whether or not an ACK is received from the base station 12 within a predetermined time after transmitting the test signal in step S10.

  If ACK is received in step S16, the process proceeds to step S18. In step S18, the terminal 14 starts communication with the base station 12 under the first communication condition and ends the process. Furthermore, in this case, in step S20, the base station 12 determines that communication has started, and ends the process.

  If ACK is not received in step S16, the process proceeds to step S22, and the terminal 14 transmits a test signal to the base station under a second communication condition (for example, communication channel f2, transmission rate M1) different from the first communication condition. 12 to send.

  In step S24, as in step S12, the base station 12 determines whether or not a test signal has been received from the terminal 14. If a test signal has been received, the process proceeds to step S26. If a test signal has not been received, the process proceeds to step S32.

  In step S26, the base station 12 updates the communication condition associated with the terminal 14 to the second communication condition while transmitting ACK to the terminal 14 under the second communication condition.

  In step S28, the terminal 14 determines whether or not an ACK has been received from the base station 12 within a predetermined time after transmitting the test signal in step S22.

  If an ACK is received in step S28, the process proceeds to step S30. In step S30, the terminal 14 starts communication with the base station 12 under the second communication condition and ends the process. Further, in this case, in step S32, the base station 12 determines that communication has started and ends the process.

  If ACK is not received in step S28, the process returns to step S22, and the terminal 14 uses a third communication condition (for example, communication channel f2, transmission rate M2) different from the first communication condition and the second communication condition. A test signal is transmitted to the base station 12.

  Thereafter, the processing from step S22 to step S32 is repeatedly executed until communication conditions between the base station 12 and the terminal 14 are set. If communication between the base station 12 and the terminal 14 cannot be performed under all communication conditions that can be set in the base station 12 and the terminal 14, the processing is terminated. In this case, the PC 16 may display to notify the user that the base station 12 and the terminal 14 cannot communicate.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning of this invention.

  For example, in the above-described embodiment, the terminal 14 transmits a test signal, and the base station 12 that has received the test signal returns an ACK to set the communication condition between the two apparatuses. However, the base station 12 transmits the test signal. Then, the communication condition between the two devices may be set by the terminal 14 receiving it returning ACK.

  In the above embodiment, the terminal 14 transmits a test signal once under the first communication condition, and transmits a test signal under another communication condition (second communication condition) when an ACK is not returned. However, when an ACK to the test signal transmitted in the first communication condition is not returned, the test signal is transmitted a plurality of times under the first communication condition, and when the ACK is not returned, the second communication condition is set. Then, a test signal may be transmitted.

  Moreover, in the said embodiment, although the received signal strength detection part 72 was used as a communication quality detection part, another structure may be sufficient as a communication quality detection part. For example, when the S / N ratio detection unit for detecting the S / N ratio of the received signal is provided in the terminal 14 as the communication quality detection unit, and the S / N ratio of the received signal becomes a predetermined level or less, the base station 12 And the communication conditions between the terminals 14 may be reset. In addition, as a communication quality detection unit, a communication history acquisition unit that acquires a communication success / communication failure history and stores it in the storage unit 50 each time communication is performed between the base station 12 and the terminal 14 is provided in the terminal 14. When the number of communication failures becomes a predetermined number or more, the communication conditions between the base station 12 and the terminal 14 may be reset.

  10 wireless communication systems, 12 base stations, 14 terminals, 16 PCs, 20, 50 storage units, 22, 52 control units, 24 transmission frame processing units, 26, 54 modulation units, 28, 56 D / A processing units, 30, 58 transmit RF unit, 32, 60 RF switch, 34, 62 antenna, 36, 64 receive RF unit, 38, 66 A / D processing unit, 40 channel filter group, 42 demodulation unit group, 44 receive frame processing unit, 68 channels Filter, 70 demodulator, 72 received signal strength detector.

Claims (4)

A wireless communication system including a first wireless device and a second wireless device connected so as to be capable of wireless communication,
The first wireless device is
A reception confirmation signal transmitter for transmitting a reception confirmation signal to the second wireless device when a communication test signal is received from the second wireless device;
With
The second wireless device is
A communication condition setting unit for setting communication conditions for the first wireless device;
The communication test signal is transmitted to the first wireless device under a first communication condition, and the reception confirmation signal is transmitted from the first wireless device within a predetermined time after transmitting the communication test signal under the first communication condition. A communication test signal transmitter for transmitting the communication test signal to the first wireless device under a second communication condition different from the first communication condition when not received;
With
When the second wireless device receives the reception confirmation signal from the first wireless device within a predetermined time after transmitting the communication test signal under the first communication condition, the first wireless device and the second wireless device The device starts communication under the first communication condition, and the second wireless device receives the reception confirmation signal from the first wireless device within a predetermined time after transmitting the communication test signal under the second communication condition. In this case, the first wireless device and the second wireless device start communication under the second communication condition.
A wireless communication system. The second wireless device is
A communication quality detection unit for detecting communication quality between the first wireless device and the second wireless device;
Further comprising
When the first wireless device and the second wireless device are communicating under the first communication condition and the detected communication quality is equal to or lower than a predetermined level, the communication test signal transmitting unit Transmitting the communication test signal to the first wireless device under two communication conditions;
The wireless communication system according to claim 1, wherein: The first communication condition and the second communication condition include a communication channel and a transmission rate.
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. A wireless device connected to another wireless device for wireless communication,
A communication condition setting unit for setting communication conditions for the other wireless device;
A communication test signal is transmitted to the other wireless device under a first communication condition, and a reception confirmation signal is received from the other wireless device within a predetermined time after the communication test signal is transmitted under the first communication condition. If not, a communication test signal transmitter for transmitting the communication test signal to the other wireless device under a second communication condition different from the first communication condition;
With
If the reception confirmation signal is received from the other wireless device within a predetermined time after transmitting the communication test signal under the first communication condition, communication is performed with the other wireless device under the first communication condition. And when the reception confirmation signal is received from the other wireless device within a predetermined time after transmitting the communication test signal under the second communication condition, the second wireless device receives the second Start communication under communication conditions.
A wireless device characterized by the above.

Images