JP2006121394A - Wireless communication apparatus and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus in which information defect by receiving errors at the time of broadcast communication is suppressed and processing load at the time of two-way communication is suppressed. <P>SOLUTION: In the radio communication apparatus which performs a TDMA communication at a control station 300, a first driven station 100, and a second driven station 200; in the case of data communication where retransmission control is disbled, data communication is conducted with a packet size packetized by a data memory 306 transmittable in one slot, and in the case of data communication where retransmission control is enabled, the data communication is performed by increasing the packet size packetized by the data memory 306. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication apparatus that performs data transmission by wireless communication.

  In recent years, security cameras have been installed to increase security awareness. In conventional security cameras, since the camera and the monitor are connected by wire, the installation place of each camera is greatly limited. In recent years, a system in which the camera and the monitor are connected wirelessly has been developed.

  The operation of such a data transmission system such as a wireless camera using wireless will be described. A data transmission system is disclosed in Patent Document 1, for example. When performing data communication by wireless communication, a technique of performing data communication based on an OSC hierarchical structure is generally used. Even in a security camera in which a camera and a monitor are connected wirelessly, the physical layer, data link layer, and network layer are cameras. The security layer is configured for wireless communication between the monitor and the upper layer, and the upper layer uses the configuration of a conventional security camera connected by wire. That is, when transmitting image data from the camera to the monitor, first, a wireless communication path is established according to the protocol below the network layer, and the image data passed from the upper layer is transferred from the camera to the monitor according to the data link layer protocol. Sent.

In addition, as disclosed in Japanese Patent Application No. 2004-109800 of an unpublished in-house application, data from one camera is received by a plurality of monitors by broadcast communication in which the same transmission signal from the camera is received by a plurality of monitors. We proposed a method to display with.
JP 60-67954 A

  However, a conventional wireless communication system that transmits image data by broadcast communication has a problem that when the wireless quality deteriorates, the received data is lost and the image is disturbed. In the above-described invention that reduces the frequency of occurrence of missing received data by transmitting the same data multiple times, there is a problem that image disturbance becomes noticeable when missing received data occurs. It was.

  Further, in a conventional wireless communication system that transmits image data by broadcast communication, image data transmitted by a camera is directly received by a monitor, so that control is complicated when a plurality of cameras are viewed on a single monitor. It had the problem that.

  In the present invention, data from a transmission source (camera) is transmitted to a reception side (monitor) via a control station, and the packetized data length is variable according to the communication state of data transmission between the control station and the reception side. The main feature is to control.

  The wireless communication device and the wireless communication system of the present invention transmit data from a transmission source (camera) to a reception side (monitor) via a control station, and according to the communication state of data transmission between the control station and the reception side. Since the data length to be packetized is variably controlled, in the case of broadcast communication in which the communication method does not perform retransmission control, transmission is performed by reducing the packet size, thereby causing a reception error that occurs during broadcast communication. Information loss can be reduced, packet size can be increased during bidirectional communication with retransmission control, the number of packets when transmitting the same amount of data can be reduced, and additional information for packetization can be reduced There is an advantage that the effective transmission rate of the transmission data is suppressed from decreasing.

  In addition, since the wireless communication device and the wireless communication system of the present invention transmit data from the transmission source (camera) to the reception side (monitor) via the control station, the reception side is connected to the same control station. It is possible to receive data from multiple transmission sources (cameras) simply by performing reception, and multiple cameras can be viewed on individual monitors without complicating the control of individual receivers (monitors). There is an advantage that

  The present invention easily realizes a wireless system that receives transmission data from one or a plurality of transmission sources (cameras) by a plurality of devices (monitors), and receives transmission data from one transmission source by a plurality of devices. In order to reduce the loss of information due to reception errors that occur during broadcast communications and to suppress the decrease in the effective transmission rate of transmission data during bidirectional communication, the sender (camera ) Is transmitted to the reception side (monitor), and the data length to be packetized is variably controlled according to the communication state of data transmission between the control station and the reception side.

  In order to solve the above problems, a first invention is composed of a first dependent station that transmits data, one or more second dependent stations that receive data, and a control station. The control station receives the data transmitted from the dependent station, the control station transmits the received data, and the second dependent station transmits the data transmitted by the control station from the first dependent station. A wireless communication device that receives received data at a second subordinate station, wherein the control station modulates a transmission signal to generate a wireless signal, and demodulates the received wireless signal to generate reception data. A first data communication means for performing data communication with the first dependent station, a data storage means for storing data received from the first dependent station, and a second dependent station Communication with the second data communication means for performing data communication and the second dependent station A communication state storage means for storing the system and a control means for controlling the entire apparatus, wherein the second data communication means is packetized in a predetermined size according to the state of the communication state storage means and is second dependent. The control station receives data transmitted from the first subordinate station, and transmits the data from the control station to the second subordinate station. By receiving a signal from the control station, the station can receive data transmitted from a plurality of first dependent stations without performing complicated control at the second dependent station. is there.

  Further, by changing the packet size when data is transmitted from the control station to the second subordinate station according to the communication method between the control station and the second subordinate station, the control station and the second subordinate station are changed. Enables optimal packetization according to the communication method between stations. In data communication that does not perform retransmission control, the packet size is reduced to reduce transmission data loss when a reception error occurs. Has an advantage that the packet size can be increased and a decrease in data transmission rate due to the addition of additional information for packetization can be suppressed.

According to a second aspect of the present invention for solving the above-mentioned problems, one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N times at a predetermined time (hereinafter referred to as a slot), and A wireless communication apparatus that performs wireless communication by a time division multiplexing (hereinafter referred to as TDMA) method for performing communication in a slot, adds an error detection code for error detection to each piece of data transmitted in each slot, and performs transmission and reception. The communication state storage means stores whether the data transmission to the second dependent station is a communication state in which retransmission control is not performed or a communication state in which retransmission control is performed, and when the communication state storage means is in a communication state in which retransmission control is not performed The second transmission data communication means packetizes the data with a data length that can be transmitted in one slot or less, and when the communication state storage means is in a communication state in which retransmission control is performed, Is packetized with a data length that can be transmitted in at least one slot or less, and is transmitted so as to be transmitted to the second subordinate station. In a data communication state in which retransmission control is not performed, one slot Packets are transmitted within a data length that can be transmitted in the above manner, so that the loss of transmission data when a reception error occurs is suppressed to a data length that is transmitted in one slot or less, and at least one slot or more in a data communication state in which retransmission control is performed. Since the packetization is performed with a data length that is less than or equal to the data length that can be transmitted, the advantage is that it is possible to suppress a decrease in data transmission rate due to the addition of additional information for packetization.

  According to a third aspect of the present invention for solving the above-mentioned problems, one slot of a predetermined time interval (hereinafter referred to as a frame) is divided into N times at a predetermined time (hereinafter referred to as a slot), and each slot is divided. A wireless communication apparatus that performs wireless communication by a time division multiplexing (hereinafter referred to as TDMA) system for performing communication, adds an error detection code for error detection to each data transmitted in each slot, and performs transmission / reception. The state storage means stores whether the data transmission to the second dependent station is a communication state by broadcast communication or a communication state by bidirectional communication, and when the communication state storage means is a communication state by broadcast communication, The transmission data communication means is packetized with a data length that can be transmitted in one slot or less, and when the communication state storage means is in a communication state by bidirectional communication, the second transmission data communication means is at least Data that can be transmitted in one slot when it is in a communication state by broadcast communication and packetized with a data length that can be transmitted in the slot or longer and transmitted to the second dependent station. Since packetization is performed with a length less than or equal to the length of the packet, transmission data loss when a reception error occurs is suppressed to less than or equal to the data length transmitted in one slot. Since packetization is performed below, there is an advantage that it is possible to suppress a decrease in data transmission rate due to addition of additional information for packetization.

  In order to solve the above problems, a fourth invention comprises a first dependent station that transmits data, one or more second dependent stations that receive data, and a control station. The control station receives the data transmitted from the dependent station, the control station transmits the received data, and the second dependent station transmits the data transmitted by the control station from the first dependent station. Communication system for receiving data to be received by a second subordinate station, wherein the control station combines packets received from the first subordinate station as necessary and transmits them to the second subordinate station. The packet is converted into a packet having a data length determined in advance according to the communication method between the station and the second subordinate station, and is transmitted to the second subordinate station. From the first subordinate station, Receive data to be transmitted at the control station, By transmitting the signal to the second dependent station and receiving the signal from the control station, the second dependent station can perform complex control from the plurality of first dependent stations without performing complicated control by the second dependent station. There is an advantage that it is possible to receive data to be transmitted. Further, by changing the packet size when data is transmitted from the control station to the second subordinate station according to the communication method between the control station and the second subordinate station, the control station and the second subordinate station are changed. Enables optimal packetization according to the communication method between stations. In data communication that does not perform retransmission control, the packet size is reduced to reduce transmission data loss when a reception error occurs. Has an advantage that the packet size can be increased and a decrease in data transmission rate due to the addition of additional information for packetization can be suppressed.

According to a fifth aspect of the present invention for solving the above-mentioned problems, one slot of a predetermined time interval (hereinafter referred to as a frame) is divided into N times at a predetermined time (hereinafter referred to as a slot), and each slot is divided. A wireless communication system that performs wireless communication using a time division multiplexing (hereinafter referred to as TDMA) method for performing communication and adds an error detection code for error detection to each data transmitted in each slot and performs transmission and reception. When the packet transmission between the control station and the second subordinate station does not perform retransmission control, the packet is transmitted within a data length that can be transmitted in one slot, and the second subordinate station sends the packet to the second subordinate station. When transmitting a packet to a station and transmitting a packet while performing retransmission control during packet transmission between the control station and the second subordinate station, the packet is transmitted in at least one slot. Packetized with a data length shorter than the possible data length and operated so as to be transmitted to the second subordinate station. When in a data communication state in which retransmission control is not performed, the data length is shorter than the data length that can be transmitted in one slot. Since packetization is performed, transmission data loss when a reception error occurs is suppressed to a data length that is transmitted in one slot or less, and in a data communication state in which retransmission control is performed, a data length that can be transmitted in at least one slot or less. Since packetization is performed, there is an advantage that it is possible to suppress a decrease in data transmission rate due to addition of additional information for packetization.

  According to a sixth aspect of the present invention for solving the above-described problems, one slot (hereinafter referred to as a frame) having a predetermined time interval is divided into N times at a predetermined time (hereinafter referred to as a slot). A wireless communication system that performs wireless communication using a time division multiplexing (hereinafter referred to as TDMA) method for performing communication and adds an error detection code for error detection to each data transmitted in each slot and performs transmission and reception. When the packet transmission between the control station and the second dependent station is performed by broadcast transmission, the packet is transmitted within the data length that can be transmitted in one slot, and the packet is transmitted from the control station to the second dependent station. When transmission is performed and packet transmission between the control station and the second subordinate station is performed by bidirectional communication, data that can be transmitted in at least one slot or more is transmitted. It is designed to be packetized below the length and transmitted to the second subordinate station, and when it is in a communication state by broadcast communication, it is packetized below the data length that can be transmitted in one slot. The loss of transmission data when a reception error occurs is suppressed to the data length that is transmitted in one slot or less, and when the communication state is bidirectional communication, it is packetized within the data length that can be transmitted in at least one slot or more. There is an advantage that it is possible to suppress a decrease in the data transmission rate due to the addition of additional information for the purpose of conversion.

  According to a seventh aspect of the present invention for solving the above-described problems, one slot (hereinafter referred to as a frame) of a predetermined time interval is divided into N times at a predetermined time (hereinafter referred to as a slot), and each slot is divided. A control station for transmitting a control signal for synchronizing with TDMA, and a first subordinate station for transmitting data in synchronization with the control station. The control station receives data transmitted from the first dependent station, and the control station transmits the received data. The second dependent station is configured by one or more second dependent stations that receive data. The station is a wireless communication apparatus that receives data transmitted from the first dependent station at the second dependent station by receiving data transmitted by the control station, and the first dependent station Use one or more slots synchronously Data communication means for packetizing transmission data into packets to be transmitted in one or more slots and performing transmission while performing predetermined retransmission control in the control station is provided, and the control station uses the one or more slots to A first data communication means for receiving packetized transmission data transmitted from one subordinate station while performing predetermined retransmission control, and received data received by the first data communication means And a second data communication means for packetizing the received data stored in the storage means into packets that can be transmitted in one slot and transmitting the same by broadcast transmission in a predetermined procedure. The station includes data communication means for receiving packetized transmission data transmitted from the control station in a predetermined procedure. From the dependent station to the control station, data is transmitted at high speed in a plurality of slots. The control station temporarily stores the received data and transmits the stored received data to the second dependent station by broadcast transmission at a constant rate. Therefore, the radio state between the first dependent station and the control station is temporarily deteriorated, data retransmission occurs, and the communication speed can be temporarily transmitted to the second dependent station by broadcast transmission. Even if the communication speed is lower than the communication speed, the received data from the first subordinate station stored in the storage means can be transmitted, and the communication speed can be kept constant. Since transmission is performed in packets that can be transmitted in one slot, there is an advantage that it is possible to reduce reception data that is lost when a reception error occurs.

According to an eighth aspect of the present invention made to solve the above-described problem, the second dependent station includes response input notification means for notifying the control station of a response input when an input for responding to data communication is performed, When the second data communication means of the station is notified that the response input has been made from the second dependent station, the transmission data stored in the storage means is packetized into packets transmitted in one or more slots. The operation is switched to perform transmission while performing predetermined retransmission control to the second dependent station, and the data communication means of the second dependent station performs predetermined retransmission control when a response operation is performed. The operation is switched so as to perform reception, and the communication system between the control station and the second dependent station is switched from the broadcast communication to the communication system performing retransmission control by operating the second dependent station. thing The advantage is that convenience is improved, and the processing load can be reduced by packetizing and transmitting / receiving packets during communication after response to packets transmitted in one or more slots. There is.

  According to a ninth aspect of the invention for solving the above-mentioned problems, when data is transmitted from the control station to the second dependent station by broadcast transmission, the packet is broadcast in the slot transmitting the control signal. As a result, broadcast transmission from the control station to the second subordinate station eliminates the need for transmission in a new slot, enables efficient use of frequency and slot resources, and allows data from the first subordinate station to be transmitted. When received, there is an advantage that transmission to the second dependent station is always possible.

  According to a tenth aspect of the present invention, the first dependent station starts data transmission in two or more sets of radio slots, the second dependent station responds, and is determined in advance as a control station. When switching the operation to perform reception while performing retransmission control, the number of radio slots used between the first dependent station and the control station is reduced, and the control station performs retransmission control with the second dependent station. When performing bidirectional communication involving the first and second dependent stations, the number of wireless slots used between the first dependent station and the control station is reduced, and bidirectional wireless communication between the second dependent station and the control station is started. There is no risk that there will be no free space and frequency for bidirectional wireless communication between the two dependent stations and the control station, and the bidirectional wireless communication between the second dependent station and the control station is always possible. There is.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a wireless communication apparatus according to the present invention. FIG. 2 is an explanatory view for explaining the operation of wireless communication by TDMA of the wireless communication apparatus of the present invention. FIG. 3 is an explanatory diagram showing a format of data transmitted in one slot of the wireless communication apparatus of the present invention. FIG. 4 is an explanatory diagram showing a format of data transmitted in one information data field in the broadcast communication of the wireless communication apparatus of the present invention. FIG. 5 is an explanatory diagram showing a format of data transmitted in one information data field in the bidirectional communication of the wireless communication apparatus of the present invention.

  FIG. 6 is an explanatory diagram showing how transmission data (image data) is divided by the wireless communication apparatus of the present invention. FIG. 7 is a sequence diagram when data is transmitted in the broadcast communication of the wireless communication apparatus of the present invention. FIG. 8 is a sequence diagram when data is transmitted in the bidirectional communication of the wireless communication apparatus of the present invention.

In FIG. 1, reference numeral 100 denotes a wireless camera that transmits captured image data, an antenna 101 that transmits and receives wireless signals, a wireless unit that modulates transmission data to generate wireless signals, and demodulates received wireless signals. 102, an error detection code is added to the transmission data to generate a data sequence of the transmission slot synchronized with the TDMA frame, and the data sequence of the reception slot synchronized with the TDMA frame is separated from the demodulated data received. A frame processing unit 103 that performs error detection, and a transmission packet that is transmitted in one slot by dividing packetized image data into data lengths that can be transmitted in TDMA slots, adding information necessary for retransmission control, and the like. A data communication processing unit 104 that performs retransmission control of a transmission packet by a generated retransmission control command; The camera unit 110 that converts the captured video to analog and outputs it, the image data processing unit 111 that digitally converts the signal input from the camera unit 110 to generate image data, and the image data processing unit 111 A transmission image data processing unit 112 that performs packetization for transmitting image data by wireless communication, a detection unit 130 that detects that a person approaches the camera, and a control unit 150 that performs overall control of the wireless camera 100 Composed.

  Reference numeral 200 denotes a wireless monitor that displays image data received from the wireless camera 100. The antenna 201 transmits and receives wireless signals, modulates transmission data to generate wireless signals, and demodulates received wireless signals. Radio section 202 adds an error detection code to transmission data, generates a data sequence of a transmission slot synchronized with a TDMA frame, and receives a data sequence of a reception slot synchronized with a TDMA frame from the demodulated data received and demodulated The frame processing unit 203 for detecting errors, the data communication processing unit 204 for performing retransmission control as necessary based on the sequence number of the received data, and the image based on the output of the data communication processing unit 204 A received image data processing unit 212 that reconstructs data, and an image data processing unit 21 that performs analog conversion on the received image data. When a display unit 210 for displaying the received image, in response, an operation unit 230 for inputting a cutting operation, consists of a control unit 250 that performs overall control of the wireless monitor 200.

  Reference numeral 300 denotes a control station that receives data from the wireless camera 100 and transmits the received data to the wireless monitor 200. The antenna 301 transmits and receives wireless signals, modulates transmission data, generates wireless signals, and A radio unit 302 that demodulates the received radio signal, adds an error detection code to the transmission data, generates a data sequence of a transmission slot synchronized with the TDMA frame, and generates a TDMA frame from the demodulated data received and demodulated A frame processing unit 303 that performs error detection and separates a data sequence of reception slots that are synchronized with each other, a first data communication processing unit 304 that performs retransmission control for receiving a packet of image data from the wireless camera 100, One slot is divided by dividing the image packet into data lengths that can be transmitted in TDMA slots and adding information necessary for retransmission control, etc. A transmission packet to be transmitted is generated, and a data communication processing unit 305 that performs retransmission control of the transmission packet according to the received retransmission control command, and image data received from the wireless camera 100 are stored, and a communication state storage to be described later Whether the image data received from the wireless camera 100 with a data length according to the state of the unit 313 is packetized and output, whether the communication state of the data storage unit 306 and the second data communication processing unit 305 is in communication with retransmission control. The communication state storage unit 313 stores whether communication is performed without control, and the control unit 350 performs overall control of the control station 300.

  Next, operations of the wireless camera 100, the wireless monitor 200, and the control station 300 configured as described above will be described.

  The control station 300 operates as a TDMA control station, and transmits a control signal for synchronization in a specific slot of each TDMA frame. When the wireless camera 100 operating as a dependent station transmits an image, it synchronizes with the TDMA timing of the control station 300 and retransmits with the control station 300 by bidirectional communication using a corresponding transmission / reception slot of the TDMA. The image data is transmitted to the control station 300 while performing the control. The wireless monitor 200 operating as a dependent station receives a control signal and prepares for reception of image data sent from the control station 300 while maintaining TDMA synchronization with the control station 300. That is, when the detection unit 130 of the wireless camera 100 detects that a person is approaching, the wireless camera establishes a wireless link for two-way communication with the control station 300 and performs retransmission control to the image to the control station 300. Start sending data. When reception of image data from the wireless camera 100 is started, the control station 300 starts an operation of transmitting the received image data to the wireless monitor 200 without performing retransmission control by broadcast communication. When the wireless monitor 200 receives the image data from the control station 300, the wireless monitor 200 displays the received image on the display unit 210. When a response operation is performed on the operation unit 230 of the wireless monitor 200, bidirectional communication between the control station 300 and the wireless monitor 200 is started until the disconnection operation is performed on the operation unit 230 while performing retransmission control. Communication continues.

  Next, the operation of TDMA will be described with reference to FIG. In FIG. 2, the camera corresponds to the wireless camera 100, and the monitor corresponds to the wireless monitor 200. In FIG. 2, one frame is divided into eight slots from slot 1 to slot 8, and the control station 300 performs transmission in the first half slot, that is, slot 1 to slot 4, and in the second half slot, that is, slot 5 to slot 8. The operation example of TDMA which the wireless camera 100 and the wireless monitor 200 which are subordinate stations transmit is shown. In FIG. 2, slot 1 of each frame is a control slot (hereinafter referred to as a control slot), and the control station 300 transmits a control signal in slot 1 of each frame. In addition, the control station 300 prepares for transmission of a call request signal from the wireless camera 100 and the wireless monitor 200, and sets a slot 5 which is a transmission slot of the wireless camera 100 and the wireless monitor 200 and is opposite to the control slot of the control station 300. The slots 6, 7, and 8 are received except for the above.

  In the example of FIG. 2, until the frame 1, the wireless camera 100 and the wireless monitor 200 only receive control signals from the control station 300. The detection unit 130 of the wireless camera 100 reacts in the frame 2, and the wireless camera 100 transmits a wireless link establishment request message to the control station 300 in the slot 6. The control station 300 determines a wireless link establishment request message and transmits a wireless link establishment request response message to the wireless camera 100 in the slot 2 of the frame 3 which is the opposite slot of the slot 6. Thereafter, a wireless link between the wireless camera 100 and the control station 300 is established in the slot 2 and the slot 6, and a bidirectional data communication state is established. Image data is transmitted from the wireless camera 100 to the control station 300 while performing retransmission control. Become so.

  In addition, the control station 300 transmits data to the wireless monitor 200 after the data communication with the wireless camera 100 is established, that is, from the frame 4 (not shown) to the wireless monitor 200 by broadcast communication without retransmission control in the control slot. Transmission of image data received from the wireless camera 100 is started. The wireless monitor 200 is controlled to receive image data from the wireless camera 100 transmitted in the control slot of the control station 300 and display it on the display unit 210. With the above operation, image data is transmitted from the wireless camera 100 to the control station 300 by data communication with retransmission control, and the control station 300 wirelessly transmits the received image data to the wireless monitor 200 by broadcast communication without retransmission control. A state for transmission to the monitor 200 is established.

  In such a state, when the response operation is started by operating the operation unit 230 of the wireless monitor 200 in the frame 10, the wireless monitor 200 sends a wireless link establishment request message to the control station 300 in the slot 7 of the frame 10. Send. The control station 300 determines a radio link establishment request message and transmits a radio link establishment request response message to the radio monitor 200 in the slot 3 of the frame 11 which is the opposite slot of the slot 7. Thereafter, a wireless link is established in slot 3 and slot 7 to establish a bidirectional data communication state, a data communication path for performing retransmission control is established, and data communication between the control station 300 and the wireless monitor 200 performs retransmission control. There is a change from non-broadcast communication to bidirectional data communication with retransmission control.

  FIG. 3 shows a format of a signal transmitted in one slot. As shown in FIG. 3, a signal transmitted in one slot controls a synchronization signal for synchronizing the slot, an identification code for identifying the sender, and the start and end of bidirectional communication. It consists of a control data field composed of control data such as a control signal, an information data field composed of image data and a command for retransmission control, and a CRC code for error detection. The data length of each component is all It is fixed at a constant value in the slots.

FIG. 4 shows the structure of an information packet transmitted in the information data field of 1 slot during broadcast communication without retransmission control. As shown in FIG. 4, the information packet transmitted in the information data field includes an information packet sequence number, an information length header portion indicating the effective information length of transmission data, and a transmission data packet portion for transmitting a transmission packet of image data. Consists of. Similarly, FIG. 5 shows the structure of an information packet transmitted in the information data field of 1 slot during bidirectional communication with retransmission control. As shown in FIG. 5, the information packet transmitted in the information data field includes a connection information portion of the transmission data packet, a header portion of the information length indicating the sequence number of the information packet and an effective information length of the transmission data, and a transmission packet of the image data. Is composed of a transmission data packet portion for transmitting. The concatenation information is used to transmit an image packet that exceeds the data length that can be transmitted in one information data field. In the case of an image packet in the middle of division, the concatenation information is 0, and the last of the divided image packets. In the case of data or an image packet that is not divided, the connection information is set to 1 so that the image packet is divided and reconstructed.

  FIG. 6 shows an example in which image data for one screen is divided into image packets and packetized. As shown in FIG. 6, the image data sequence for one screen is divided into data lengths that can be transmitted in one transmission data packet, or data length longer than that, and each packet is packetized with a header. Is completed, and each image packet is transmitted in an information data field of one slot or a plurality of slots.

  Next, the operation of each unit when the wireless camera 100 starts image transmission and performs a response operation on the wireless monitor 200 will be described.

  When the detection unit 130 of the wireless camera 100 detects that a person is approaching, the control unit 150 generates a wireless link establishment request message to establish a wireless link with the control station 300, and the frame processing unit Control to send a message to 103. When the response message of the transmitted wireless link establishment request message is received from the control station 300, the control unit 150 controls to transmit the image captured by the camera unit 110 to the control station 300 by data communication with retransmission control. . That is, the transmission image data processing unit 112 requests the image data processing unit 111 to output image data, and the image data processing unit 111 digitally converts the image signal input from the camera unit 110 and outputs one image. Are generated and output to the transmission image data processing unit 112. Then, the transmission image data processing unit 112 divides one piece of image data, adds a header to packetize, and outputs one completed image packet to the data communication processing unit 104. Thereafter, each time the transmission of an image packet is notified from the data communication processing unit 104, the image packet is sequentially output to the data communication processing unit 104. When transmission of one image packet is completed, the image data processing unit 111 is requested to output image data again, and thereafter, the image data is packetized and output to the data communication processing unit 104 in the same manner. Thus, the transmission of the image data is continued.

  Note that the control station 300 performs image data reception processing while performing retransmission control with the wireless camera 100 by establishing a wireless link with the wireless camera 100. The control unit 350 controls the first data communication processing unit 304 to start data communication for performing retransmission control. The first data communication processing unit 304 reconstructs the reception data based on the header information of the reception data transmitted from the wireless camera 100. The first data communication processing unit 304 determines whether there is a missing number in the sequence number of the information packet shown in FIG. 5, and if there is no missing number, extracts the received data based on the effective information length of the transmission data. When there is a missing number, a retransmission request (hereinafter referred to as NAK) in which the missing number is set is transmitted to request the wireless camera 100 to retransmit the missing number, and the received data is discarded. Further, the first data communication processing unit 304 determines whether or not there is continuous data based on the connection information of the transmission data packet. If there is continuous data, the first data communication processing unit 304 holds the received data. If there is no continuous data, the first data communication processing unit 304 holds it. The received data is reconstructed by concatenating the received data this time with the received data, and the data is output to the data storage unit 306, and a delivery confirmation (hereinafter referred to as ACK) is set with a number added to the sequence number of the received information packet Transmit and request the wireless camera 100 for the next data packet. The data storage unit 306 holds the received image data from the first data communication processing unit 304.

The control station 300 transmits image data to the wireless monitor 200 by broadcast communication without retransmission control while receiving image data from the wireless camera 100 by bidirectional communication with retransmission control.
The control station 350 sets “no retransmission control” in the communication state storage unit 313 and controls the second data communication processing unit 305 to transmit data by broadcast communication. The data storage unit 306 packetizes the image data received from the wireless camera 100 into a packet size that can be transmitted in one predetermined slot when the communication state storage unit 313 is “no retransmission control”, and the second data communication processing To the unit 305. At this time, in order to complete the transmission of one image packet in the information data field transmitted in one slot, the data length of one image packet is broadcast by broadcast communication that does not perform retransmission control from the information data field length. The header (information length indicating the order number of the information packet and the effective information length of the transmission data) given by the second data communication processing unit 305 and the header given by the data storage unit 306 are subtracted when transmitting the image packet. The image data is divided so as to be less than or equal to the value.

  The second data communication processing unit 305 adds a header including a transmission number and an information length that are updated one by one for each transmission data packet to be transmitted in one slot to the received image packet, generates a transmission data packet, and generates a frame processing unit It outputs to 303. In the slot that is transmitting the control signal, the frame processing unit 303 transmits the identification code of the transmission source in the control data field and the synchronization signal for slot synchronization and the CRC for error detection so as to transmit the communication data packet in the information data field. And a data string of the control slot is generated and output to the radio unit 302. Then, the signal is modulated by the wireless unit 302 and transmitted from the antenna 301 to the wireless monitor 200. Further, when the data transmission is completed, the frame processing unit 303 notifies the second data communication processing unit 305 of the transmission completion, and the second data communication processing unit 305 determines that the transmission of the transmission data packet is completed, and the data storage unit 306 Next, the data storage unit 306 packetizes to a packet size that can be transmitted in one predetermined slot and transmits the packet to the second data communication processing unit 305, so that the image data is transmitted by broadcast communication. Transmission continues.

  On the other hand, the control unit 250 of the wireless monitor 200 controls each unit so as to receive the transmission signal of the control slot transmitted from the control station 300. The radio signal transmitted from the control station 300 is demodulated by the radio unit 202, and the demodulated signal is output to the frame processing unit 203. In the frame processing unit 203, data received based on the synchronization signal is separated into a control data field, an information data field, and a CRC, and a reception error is determined based on a CRC error detection code, and there is no reception error. In this case, the data in the information data field is output to the data communication processing unit 204.

  The data communication processing unit 204 extracts an image data packet from the data in the information data field based on the information length, and outputs it to the received image data processing unit 212. The received image data processing unit 212 deletes the header of the image data packet and reconstructs the image data, and outputs the image data to the image data processing unit 211 each time image data for one sheet is completed. The processing unit 211 operates to display the received image on the display unit 210 by converting the received image data into analog data and outputting it to the display unit 210. At this time, the data communication processing unit 204 monitors for a missing received packet based on the sequence number of the received transmission data packet. That is, each time a transmission data packet is received, the data communication processing unit 204 stores the sequence number, compares it with the sequence number of the previously received transmission data packet, and if the sequence number is lost, it is lost. The received image data processing unit 212 is notified of the number of transmitted communication packets. Then, the received image data processing unit 212 performs processing to replace the missing image data portion with data that displays a white color according to the number of missing communication packets, and performs reproduction processing of image data including a reception error. Do.

  FIG. 7 shows a sequence when image data is transmitted in the broadcast communication without retransmission. The transmission side in FIG. 7 refers to the control station 300, and the reception side refers to the wireless monitor 200. In FIG. 7, the transmission request indicates that one image packet is output from the data storage unit 306 to the second data communication processing unit 305. An arrow from the transmission side to the reception side indicates that one slot of data is transmitted by one arrow, and a number in parentheses indicates a sequence number. The reception display indicates that one image packet extracted from the communication packet received by the data communication processing unit 204 is output to the reception image data processing unit 212. As shown in FIG. 7, the image packets output from the data storage unit 306 are sequentially transmitted in one slot with a sequence number assigned thereto, and every time transmission is completed, the transmission completion is notified, and the next image packet is transmitted. Sent. On the receiving side, every time an image packet is received, the received image is transferred to the received image data processing unit 212.

  If the signal DATA (3) with the sequence number 3 cannot be received as in the example of FIG. 7, the signal DATA (4) with the sequence number 4 is next to the signal DATA (2) with the sequence number 2 on the receiving side. Is received by the data communication processing unit 204, it is detected that the signal DATA (3) with the sequence number 3 has not been received, and an error reception display for notifying the occurrence of one image packet missing is displayed. 212 is notified.

  Next, the operation of each unit when a response operation is performed on the wireless monitor 200 will be described.

  When a response operation is performed on the operation unit 230 of the wireless monitor 200 while image data is being received by the above-described broadcast communication, the operation is shifted to perform image communication while performing retransmission control by bidirectional communication. That is, when a response operation is performed on the operation unit 230 of the wireless monitor 200, the control unit 250 transmits a communication request to the control station 300 in the transmission slot on the dependent station side (slot 6 to slot 8 in FIG. 2). Control is performed so as to receive the receiving slot. At this time, a communication request command is transmitted in the control data field. On the other hand, the control station 300 always receives from slot 6 to slot 8, and received data received in these slots is separated into slots by the frame processing unit 303 and notified to the control unit 350.

  When the communication request command is received, the control unit 350 sets the communication state storage unit 313 to “with retransmission control” and notifies the frame processing unit 303 and the second data communication processing unit 305 of the start of retransmission control. Then, each part is controlled to perform image packet transmission while performing retransmission control in a transmission slot corresponding to the received slot. The data storage unit 306 changes the size of the image packet generated from the image data to a predetermined size when the communication state storage unit 313 is in the “with retransmission control” state. In the first embodiment, the following description will be given with an example in which the image packet size at this time is changed to the image packet size divided and transmitted in three slots. The data storage unit 306 is notified of the completion of transmission of the image packet from the second data communication processing unit 305 as in the case of the broadcast communication in which the retransmission control is not performed except for changing the size for dividing the image data. The image packets are sequentially output to the second data communication processing unit 305 every time.

On the other hand, the second data communication processing unit 305 that has received the notification of the start of retransmission control from the control unit 350 thereafter divides the received image packet into lengths that can be transmitted in one slot, and the concatenation information as shown in FIG. A header composed of a sequence number and an information length that are updated one by one for each transmission data packet is added, and a transmission data packet is generated and output to the frame processing unit 303. The frame processing unit 303 detects a synchronization signal for slot synchronization and error detection so as to transmit a transmission source identification code in the control data field and a communication data packet in the information data field in the transmission slot corresponding to the slot that has received the call request. Is added to the wireless unit 302. At this time, the second data communication processing unit 305 divides the received image packet into three data that can be transmitted in one slot, and the first and second transmission data packets have 0 and 3 pieces of connection information. For each transmission data packet, the concatenation information is set to 1, and every time transmission completion is notified from the frame processing unit 303, the divided transmission data packet is sent to the frame processing unit 303, and the last packet of the concatenation information 0 is sent. Is transmitted to the frame processing unit 303, and when the ACK for the last packet of the connection information 1 is received from the wireless monitor 200, the data storage unit 306 is notified of the completion of transmission. Further, if the ACK from the radio monitor 200 cannot be received after a lapse of a certain time after transmitting the transmission data packet of the connection information 1, the transmission data packet of the connection information 1 transmitted last is retransmitted.

  Next, the image data reception operation of the wireless monitor 200 in bidirectional communication will be described. When a response operation is performed on the operation unit 230 of the wireless monitor 200 while receiving image data by broadcast communication, the control unit 250 notifies the frame processing unit 203 and the data communication processing unit 204 of the start of retransmission control, and A communication request is transmitted to the control station 300, and each unit is controlled to receive the corresponding reception slot. The radio signal transmitted from the control station 300 in the slot newly activated for bidirectional communication is demodulated by the radio unit 202, and the demodulated signal is output to the frame processing unit 203. The frame processing unit 203 separates the received data based on the synchronization signal into the control data field, the information data field, and the CRC in the reception slot for two-way communication, and detects the reception error based on the CRC error detection code. When the determination is made and there is no reception error, the data in the information data field is output to the data communication processing unit 204.

  The data communication processing unit 204 first checks the sequence number, and if it is a transmission data packet of the sequence number next to the previously received sequence number, stores the received sequence number, and based on the connection information and the information length. The image packet is reconstructed. At this time, if the concatenation information of the received transmission data packet is 1, the ACK notifying that the concatenation information has been successfully received up to the transmission data packet of 1 is transmitted in the transmission slot for bidirectional communication, and is completed. The image data packet is output to the received image data processing unit 212.

  The received image data processing unit 212 deletes the header of the image data packet, reconstructs the image data, and outputs the image data processing unit 211 to the image data processing unit 211 every time one piece of image data is completed. In 211, the received image data is analog-converted and output to the display unit 210, and the display unit 210 operates to display the received image. If it is not the transmission data packet of the sequence number next to the previously received sequence number, a retransmission request is transmitted to the control station 300 so as to perform retransmission from the transmission data packet that could not be received. For example, when a transmission data packet with sequence number 4 is received next to a transmission data packet with sequence number 2, a retransmission request from sequence number 3 is bidirectionally transmitted to control station 300 so as to retry transmission from the transmission data packet with sequence number 3. Transmit in the transmitting slot during communication.

  FIG. 8 is a sequence when transmitting the image data with the retransmission. The transmission side in FIG. 8 refers to the control station 300, and the reception side refers to the wireless monitor 200. In FIG. 8, the transmission request indicates that one image packet is output from the data storage unit 306 to the second data communication processing unit 305. An arrow from the transmission side to the reception side indicates that one slot of data is transmitted by one arrow, and a number in parentheses indicates a sequence number. The reception display indicates that one image packet extracted from the communication packet received by the data communication processing unit 204 is output to the reception image data processing unit 212.

As shown in FIG. 8, the image packet output from the data storage unit 306 is divided into three transmission data packets, which are sequentially transmitted with an order number. When the transmission of three transmission data packets obtained by dividing one image packet is completed and the receiving side receives an ACK, the data storage unit 306 is notified of the completion of transmission and the next image packet is transmitted. On the receiving side, when the image packet is reconstructed from the received transmission data packet and the transmission data packet of the connection information 1 is received, the reconstructed image packet is received from the data communication processing unit 204 by the reception image data processing unit 212. And ACK is transmitted to the transmitting side.

  FIG. 8 shows an example of retransmission control, and shows the retransmission control operation when the transmission data packet with sequence number 5 (DATA (5) in FIG. 8) cannot be received. When the signal DATA (5) with the sequence number 5 cannot be received as in the example of FIG. 8, the signal transmission data packet with the sequence number 6 is next to the signal transmission data packet DATA (4) with the sequence number 4 on the receiving side. When the data communication processing unit 204 receives DATA (6), it is detected that the transmission data packet DATA (5) with the sequence number 5 has not been received, and is retransmitted from the transmission data packet DATA (5) with the sequence number 5. Retransmission request NACK (5) is transmitted. When the transmission side receives the retransmission request NACK (5), the transmission side again operates to transmit the transmission data packet from the transmission data packet DATA (5) with the sequence number 5.

  Next, how the image information is divided and packetized will be described with reference to FIG. The upper image information in FIG. 6 is image data for one screen received from the wireless camera 100. The second row shows the division in the data storage unit 306. In the example of FIG. 6, one piece of image data is divided into five image packets D11, D21, D31, D4, and D5, and each packet is packetized by adding an image packet header (H in FIG. 6). Is shown (FIG. 6, third stage). D11, D21, and D31 show the state of division and packetization when transmitting without retransmission control in broadcast communication, and D4 and D5 are the division and packet when transmitting with retransmission control in bidirectional communication. The state of conversion is shown. The fourth row shows an example in which the second data communication unit 305 divides the D4 and D5 image packets into three communication data packets. As in this example, during the transmission of an image, when a transition is made from a state in which broadcast transmission is performed without retransmission control to a state in which bidirectional transmission is performed with retransmission control, the size of the image packet is converted, and the broadcast is performed. In the state of transmission without retransmission control in communication, image data is packetized in a size that can be transmitted in one slot, and in the state of transition to the state of transmission with retransmission control in bidirectional communication, it is divided into multiple slots. Image data is packetized by size.

(Embodiment 2)
Next, another embodiment of the present invention will be described. Note that the block diagram of the wireless communication apparatus of the second embodiment is the same as the block diagram of FIG. 1 of the first embodiment, and a description thereof will be omitted.

  In the second embodiment, an operation example when the data communication speed between the wireless camera and the control station is different from the data communication speed between the control station and the wireless monitor will be described.

  In the wireless communication apparatus according to the second embodiment, data transmission from the wireless camera to the control station is performed while performing retransmission control in a plurality of slots (two pairs in this example), and data transmission between the control station and the wireless monitor is performed. Shows an example in which broadcast transmission is performed without retransmission control in one slot as in the first embodiment, and transmission is performed while performing retransmission control in one set of slots after a response by the radio monitor.

First, the operation of TDMA will be described with reference to FIG. In FIG. 9, the camera corresponds to the wireless camera 100, the monitor corresponds to the wireless monitor 200, and the control station corresponds to the control station 300. In FIG. 9, one frame is divided into eight slots from slot 1 to slot 8, and the control station 300 performs transmission in the first half slot, that is, slot 1 to slot 4, and in the second half slot, that is, slot 5 to slot 8. The operation example of TDMA which the wireless camera 100 and the wireless monitor 200 which are subordinate stations transmit is shown. In FIG. 9, slot 1 of each frame is a control slot, and the control station 300 transmits a control signal in slot 1 of each frame. Further, the control station 300 prepares for transmission of a call request signal from the wireless camera 100 and the wireless monitor 200, and sets a slot 5 which is a transmission slot of the wireless camera 100 and the wireless monitor 200 and is a slot opposite to the control slot of the control station 300. The slots 6, 7, and 8 are received except for the above.

  In the example of FIG. 9, as in the operation of FIG. 2 of the first embodiment, until the frame 1, the wireless camera 100 and the wireless monitor 200 are only receiving the control signal of the control station 300 (frame 1 is shown in FIG. 9). Not shown). The detection unit 130 of the wireless camera 100 reacts in the frame 2, and the wireless camera 100 transmits a wireless link establishment request message to the control station 300 in the slots 6 and 8. The control station 300 discriminates the wireless link establishment request message, and transmits a wireless link establishment request response message to the wireless camera 100 in the slot 2 and the slot 4 of the frame 3 which are the opposite slots of the slot 6 and the slot 8. Thereafter, the wireless link between the wireless camera 100 and the control station 300 is established in the two slots of the slot 2 and the slot 6 and the slot 4 and the slot 8, and the two-way data communication state is established, and the retransmission control is performed. Image data is transmitted from the wireless camera 100 to the control station 300. In addition, after data communication with the wireless camera 100 is established, that is, from the frame 4, the control station 300 receives the wireless monitor 200 from the wireless camera 100 by broadcast communication without retransmission control in the control slot. The transmission of the processed image data is started. The wireless monitor 200 is controlled to receive image data from the wireless camera 100 transmitted in the control slot of the control station 300 and display it on the display unit 210.

  With the above operation, image data is transmitted from the wireless camera 100 to the control station 300 by data communication with retransmission control, and the control station 300 wirelessly transmits the received image data to the wireless monitor 200 by broadcast communication without retransmission control. A state for transmission to the monitor 200 is established. In such a state, when the response operation is started by operating the operation unit 230 of the wireless monitor 200 in the frame 10, the wireless monitor 200 sends a wireless link establishment request message to the control station 300 in the slot 7 of the frame 10. Send. The control station 300 determines a radio link establishment request message and transmits a radio link establishment request response message to the radio monitor 200 in the slot 3 of the frame 11 which is the opposite slot of the slot 7. Thereafter, a wireless link is established in slot 3 and slot 7 to establish a bidirectional data communication state, a data communication path for performing retransmission control is established, and data communication between the control station 300 and the wireless monitor 200 performs retransmission control. There is a change from non-broadcast communication to bidirectional data communication with retransmission control.

  Next, the flow control of data processing when data is transferred via the control station 300 will be described with reference to FIG. The data communication processing unit 104 of the wireless camera 100 can transmit the received image packet in one slot when receiving a transmission request for image data from the transmission image data processing unit 112, as in the wireless communication apparatus of the first embodiment. Each time transmission is performed by dividing into packets, every time a delivery confirmation (ACK) is received from the control station 300, the transmission image data processing unit 112 is notified of the completion of transmission, and images are sequentially transmitted. At this time, as shown in FIG. 9, wireless camera 100 according to the second embodiment performs data transmission using two sets of slots in one frame, so that one image packet has three slots as shown in FIG. In the case of transmission by one, one image packet is transmitted by 1.5 frames.

On the other hand, the first data communication processing unit 304 of the control station 300 reconstructs the image packet every time it receives the packet of the connection information 1 and outputs it to the data storage unit 306. When there is an area for writing the received image packet, the data storage unit 306 stores the received packet, notifies the first data communication processing unit 304 of the reception confirmation, and the first data communication processing unit 304 If there is not enough area to write the received image packet, the received image packet is discarded and the retransmission request is sent to the first data communication process. The first data communication processing unit 304 operates to transmit a retransmission request (NAK) to the transmission side (wireless camera 100). Thus, when the image packet from the wireless camera 100 is received and the image data is stored in the data storage unit 306, the control unit 350 of the control station 300 stores the stored image as in the first embodiment. Control for transmitting data to the wireless monitor 200 is started. In other words, the data storage unit 306 packetizes the stored image data into packets that can be transmitted in one slot when broadcast transmission without retransmission control is performed according to the state of the communication state storage unit 313. 2 When outputting to the data communication processing unit 305 and performing bi-directional communication for performing retransmission control, it is packetized into packets transmitted across a plurality of slots and output to the second data communication processing unit 305.

  In FIG. 10, when the third image packet is received from the wireless camera 100, the free space in the data storage unit 306 is insufficient, the third image packet is discarded, and a retransmission request is made to the wireless camera 100. An example of operation is shown. In addition, when a lack of received data due to a radio error occurs between control stations from the wireless camera, the control station 300 uses the NAK to identify the missing number of the received packet as in FIG. 8 of the first embodiment. Is notified, the packet that has not been received is retransmitted (not shown).

  As described above, when transmitting the image data, the wireless communication apparatus according to the second embodiment packetizes the image data from the transmission source (wireless camera) to the control station with a packet length that extends over a plurality of slots. It operates to transmit at high speed using a plurality of slots. When image data is transmitted from the control station to the receiving side (wireless monitor), when image data received from the transmission source (wireless camera) is broadcast without retransmission control, it can be transmitted in one slot. When packetized into image packets of packet length and transmitted in one slot and transmitted by bidirectional communication while performing retransmission control, it is packetized into packet packets of a packet length extending over a plurality of slots and transmitted in one set of slots. Further, retransmission control (retransmission control protocol) between the control station and the receiving side (wireless monitor) is the same as in FIG. 8 of the first embodiment, and is the same control as the retransmission control between the transmission source (wireless camera) and the control station. (Protocol).

  As another operation example of the second embodiment, when the wireless monitor responds and bi-directional communication between the control station and the wireless monitor is started, an operation of changing the number of slots used between the wireless camera and the control station is also effective. It is. For example, when the control station transmits image data by broadcast communication using the control slot, the wireless camera and the control station communicate image data using two sets of slots and perform a response operation on the wireless monitor. When the control station and the wireless monitor start bidirectional communication, it is possible to reduce the number of slots used for communication between the wireless camera and the control station to one set and start bidirectional communication between the control station and the wireless monitor. It is.

  Further, in the second embodiment, an example is shown in which a radio communication monitor is selected, a communication request is made to the control station in the selected slot, and a radio link for bidirectional data communication is established. The control station transmits a control signal, the subordinate station makes a communication request in the slot corresponding to the slot for transmitting the control signal, selects a slot for data communication from the control station, and becomes a subordinate station in the control slot. In a system that notifies and starts bidirectional communication in the notified slot, when the wireless monitor makes a communication request, transmission / reception of a set of slots used between the wireless camera and the control station is stopped and stopped. It is also possible to use a set of slots for communication between the time control station and the radio monitor.

As described above, in the wireless communication device and the wireless communication system of the present invention, when information is transmitted without performing retransmission control, the data link layer for controlling data communication has a data size equal to or smaller than a data size that can detect a reception error, That is, in TDMA communication, transmission is performed in units of packets packetized with a packet size that is less than or equal to the data size that can be transmitted in one slot, reception error packets are discarded on the receiving side, retransmission control is performed, and information is transmitted. In the case of TDMA communication, retransmission control is performed by performing transmission in units of packets packetized with a packet size greater than the data size that can be transmitted in one slot. If not, keep information loss due to wireless communication errors small and perform retransmission control. Reduce the number of packets exchanged Link Layer which the application layer, has the effect of making it possible to reduce the processing load.

  Also, at the start of communication, data was transmitted by broadcast communication without retransmission control, and switched to bidirectional communication with retransmission control in response from the receiving side. There is an effect that data can be received simultaneously by a plurality of receiving devices without limitation, and since retransmission control is not performed during broadcast communication, processing of the entire device (system) is performed even if transmission data is reduced to a small packet. This has the effect of suppressing an increase in load.

  In addition, the packet size when transmitting information without performing retransmission control is fixed to a size that can be transmitted in one slot, and is transmitted with a sequence number, so that the order of received packets on the receiving side. It is possible to estimate the amount of missing information based on the number, and when the transmission data is image data, it becomes possible to perform supplementary processing such as replacing the missing image data portion with a white color, which is due to missing received data This has the effect of reducing the adverse effect on the application layer.

  In addition, when the control station and the receiving side are performing broadcast communication, the control station and the transmission side use multiple TDMA slots to perform data transmission at a speed higher than the communication speed of the broadcast communication. By performing the flow control in accordance with the transmission speed at, the risk of losing data to be transmitted from the control station to the receiving side is reduced, and communication at the transmission speed in theoretical broadcast communication becomes possible. Has an effect.

  At the start of communication, transmission is performed in a plurality of slots from the transmitting side, the control station performs broadcast transmission in the control slot, the receiving side responds, and the control station and the receiving side start bidirectional communication. By reducing the number of slots used between the transmission side and the control station so that the control station and the reception side perform two-way communication, the communication status between the control station and the reception side can be changed during both broadcast and bidirectional communication. The number of slots used in the whole can be made the same, and the wireless slot and the frequency resource can be effectively used.

  Furthermore, since the wireless camera transmits the image data with the retransmission control from the control station, and the wireless monitor is configured to receive the image data of the wireless camera through the control station, a plurality of wireless cameras are installed on the system. Even in the case of a wireless monitor, it is possible to view images of a plurality of wireless cameras without complicated control on the wireless monitor, and in addition, data communication is performed between the wireless camera and the control station with retransmission control. The image held in the memory has an effect that image data is not lost due to a reception error.

  The present invention relates to a TDMA wireless communication apparatus, and when retransmission control is not performed, information loss due to a wireless communication error is suppressed, and when retransmission control is performed, the number of packet exchanges between a data link layer and an application layer. And the processing load can be reduced.

Block diagram of the wireless communication apparatus of the present invention Explanatory drawing explaining operation | movement of the radio | wireless communication by TDMA of the radio | wireless communication apparatus of this invention. Explanatory drawing which shows the format of the data of the radio | wireless communication apparatus of this invention Explanatory drawing which shows the format of the data transmitted by one information data field in the broadcast communication of the radio | wireless communication apparatus of this invention Explanatory drawing which shows the format of the data transmitted by one information data field in the bidirectional | two-way communication of the radio | wireless communication apparatus of this invention. Explanatory drawing which shows the mode of the division | segmentation of the transmission data (image data) of the radio | wireless communication apparatus of this invention Sequence diagram in the case of transmitting data in the broadcast communication of the wireless communication device of the present invention Sequence diagram in the case of transmitting data in bidirectional communication of the wireless communication device of the present invention Explanatory drawing explaining operation | movement of the radio | wireless communication by TDMA of the radio | wireless communication apparatus of Embodiment 2 of this invention. Sequence diagram for explaining the operation of the second embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless camera 101 Antenna 102 Wireless part 103 Frame processing part 104 Data communication processing part 110 Camera part 111 Image data processing part 112 Transmission image data processing part 130 Detection part 150 Control part 200 Wireless monitor 201 Antenna 202 Radio | wireless part 203 Frame processing part 204 Data communication processing unit 212 Received image data processing unit 211 Image data processing unit 210 Display unit 230 Operation unit 250 Control unit 300 Control station 301 Antenna 302 Radio unit 303 Frame processing unit 304 First data communication processing unit 305 Second data communication processing unit 306 Data storage unit 313 Communication state storage unit 350 Control unit

Claims (10)

A first dependent station that transmits data, and one or more second dependent stations that receive data and a control station, and the control station receives data transmitted from the first dependent station The control station transmits the received data, and the second dependent station receives the data transmitted from the first dependent station by receiving the data transmitted by the control station. A wireless communication apparatus for receiving at a station, wherein the control station modulates a transmission signal to generate a wireless signal, demodulates the received wireless signal, and generates reception data; and Data communication is performed between the first data communication means for performing data communication with the dependent station, data storage means for storing data received from the first dependent station, and the second dependent station. Second data communication means; and the second dependent station; A communication state storage means for storing a communication method and a control means for controlling the entire apparatus, wherein the second data communication means is packetized with a predetermined size according to the state of the communication state storage means, and A wireless communication apparatus that operates to transmit to a second dependent station. A time division multiplexing (hereinafter referred to as TDMA) system in which one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N at a predetermined time (hereinafter referred to as a slot) and communication is performed in each of the slots. The wireless communication apparatus performs wireless communication and performs transmission / reception by adding an error detection code for error detection to each data transmitted in each slot, and the communication state storage means transmits the data to the second dependent station. The data transmission is stored in a communication state in which retransmission control is not performed or in a communication state in which retransmission control is performed. When the communication state storage unit is in a communication state in which retransmission control is not performed, the second transmission data communication unit includes: When the communication state storage means is in a communication state in which retransmission control is performed, the second transmission data communication means has at least 1 Packetized below the data length that can be sent over the lot, the radio communication apparatus according to claim 1 that has been characterized that operates to transmit the second tributary station. A time division multiplexing (hereinafter referred to as TDMA) system in which one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N at a predetermined time (hereinafter referred to as a slot) and communication is performed in each of the slots. The wireless communication apparatus performs wireless communication and performs transmission / reception by adding an error detection code for error detection to each data transmitted in each slot, and the communication state storage means transmits the data to the second dependent station. The second transmission data communication means is one slot when the communication state storage means is in the communication state by broadcast communication. When packetized with a data length that can be transmitted or less, and when the communication state storage means is in a communication state by bidirectional communication, the second transmission data communication means is at least one slot or more Packetized below the data length transmittable, the second radio communication apparatus according to claim 1 that has been characterized that operates to transmit to the dependent stations. A first dependent station that transmits data, and one or more second dependent stations that receive data and a control station, and the control station receives data transmitted from the first dependent station The control station transmits the received data, and the second dependent station receives the data transmitted from the first dependent station by receiving the data transmitted by the control station. A wireless communication system for receiving at a station,
When the control station combines the packets received from the first subordinate station as necessary and transmits the packet to the second subordinate station, it depends on the communication method between the control station and the second subordinate station. A radio communication system, characterized in that the radio communication system operates to packetize a packet having a predetermined data length and transmit the packet to the second dependent station. A time division multiplexing (hereinafter referred to as TDMA) system in which one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N at a predetermined time (hereinafter referred to as a slot) and communication is performed in each of the slots. A wireless communication system for performing wireless communication for performing transmission and reception by adding an error detection code for error detection to each piece of data transmitted in each slot, wherein the control station transmits the second dependent station When packet transmission is performed without performing retransmission control, packetization is performed with a data length that can be transmitted in one slot or less, and packet transmission is performed from the control station to the second dependent station.
When packet transmission between the control station and the second dependent station is performed while performing retransmission control, the packet is packetized with a data length that can be transmitted in at least one slot and transmitted to the second dependent station. The wireless communication system according to claim 4, wherein the wireless communication system operates as described above. A time division multiplexing (hereinafter referred to as TDMA) system in which one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N at a predetermined time (hereinafter referred to as a slot) and communication is performed in each of the slots. A wireless communication system for performing wireless communication for performing transmission and reception by adding an error detection code for error detection to each piece of data transmitted in each slot, wherein the control station transmits the second dependent station When packet transmission is performed by broadcast transmission, packets are packetized with a data length that can be transmitted in one slot or less, and packet transmission is performed from the control station to the second subordinate station. When the packet transmission between the second subordinate stations is performed by bidirectional communication, the packet length must be less than the data length that can be transmitted in at least one slot. DOO reduction, and wireless communication system of claim 4 which is characterized in that operate to transmit to said second subordinate station. A time division multiplexing (hereinafter referred to as TDMA) system in which one section (hereinafter referred to as a frame) of a predetermined time interval is divided into N at a predetermined time (hereinafter referred to as a slot) and communication is performed in each of the slots. And a control station that transmits a control signal for TDMA synchronization, a first subordinate station that transmits data in synchronization with the control station, and one or more second subordinates that receive data Composed of stations,
The control station receives data transmitted from the first dependent station, the control station transmits the received data, and the second dependent station receives data transmitted by the control station. A wireless communication apparatus for receiving data transmitted from the first dependent station by the second dependent station,
The first subordinate station packetizes transmission data into packets transmitted in one or more slots using one or more slots in synchronization with the control station, and performs predetermined retransmission control on the control station. Data communication means for performing transmission while performing,
The control station receives first packetized transmission data transmitted from the first dependent station using one or more slots while performing the predetermined retransmission control. And storage means for storing received data received by the first data communication means;
A second data communication unit configured to packetize the received data stored in the storage unit into packets that can be transmitted in one slot and transmit the same by broadcast transmission in a predetermined procedure;
The wireless communication apparatus, wherein the second dependent station includes data communication means for receiving packetized transmission data transmitted from the control station in accordance with the predetermined procedure. The second dependent station includes response input notification means for notifying the control station of a response input when input for responding to data communication is performed,
When the second data communication means of the control station is notified that a response input has been made from the second dependent station, the transmission data stored in the storage means is transmitted in one or more slots. The operation is switched so that transmission is performed while performing predetermined retransmission control to the second dependent station, and the data communication means of the second dependent station performs the response operation when the response operation is performed. 8. The wireless communication apparatus according to claim 7, wherein the operation is switched to perform reception while performing predetermined retransmission control. 9. The transmission of a packet in a slot transmitting a control signal when transmitting data from the control station to the second dependent station by broadcast transmission. Wireless communication device. The first subordinate station starts data transmission in two or more sets of radio slots, the second subordinate station responds, and operates to perform reception while performing predetermined retransmission control with the control station. 10. The wireless communication apparatus according to claim 8, wherein when switching is performed, a wireless slot used between the first dependent station and the control station is reduced.

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