JP2007013544A - Radio communication system and its communication method - Google Patents

Radio communication system and its communication method Download PDF

Info

Publication number
JP2007013544A
JP2007013544A JP2005191432A JP2005191432A JP2007013544A JP 2007013544 A JP2007013544 A JP 2007013544A JP 2005191432 A JP2005191432 A JP 2005191432A JP 2005191432 A JP2005191432 A JP 2005191432A JP 2007013544 A JP2007013544 A JP 2007013544A
Authority
JP
Japan
Prior art keywords
wireless communication
data
reception
communication
transmitted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2005191432A
Other languages
Japanese (ja)
Inventor
Shinji Fukuda
Kumiko Matsuo
Toshiyuki Sugitani
俊幸 杉谷
久美子 松尾
真二 福田
Original Assignee
Matsushita Electric Ind Co Ltd
松下電器産業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Ind Co Ltd, 松下電器産業株式会社 filed Critical Matsushita Electric Ind Co Ltd
Priority to JP2005191432A priority Critical patent/JP2007013544A/en
Publication of JP2007013544A publication Critical patent/JP2007013544A/en
Pending legal-status Critical Current

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that an effective rate is delayed when an image information is transmitted by a broadcast communication and a processing load for correcting an error is increased. <P>SOLUTION: A master machine 200 divides the image information photographed by a camera 101 for an entrance slave machine 100 stored in an image storage 203 into transmittable lengths in one time slot of a TDMA, sequence numbers are given respectively, and the same information is transmitted only by numbers determined on the basis of a receiving quality made to inform from a codeless slave machine 300. The overlapped and received image information is annulled, and a display is conducted on the basis of the sequence numbers given to the received image information, while the receiving quality at a time when the image information is received is made to inform to the master machine 200 in the codeless slave machine 300 on the receiving side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication system that performs data transmission by one-way broadcast communication by wireless communication and a communication method thereof.

  In recent years, due to heightened security awareness, devices that handle image signals and audio signals simultaneously, such as door phones and security cameras, are rapidly spreading. These devices are equipped with cameras, microphones, and speakers to eliminate the hassle of cabling. Wireless devices that wirelessly communicate image signals and audio signals between an input device side provided with a monitor, a microphone, and an output device side provided with a speaker are becoming widespread.

  As described above, when communication between devices is changed from wired communication to wireless communication, communication failure occurs due to the influence of interference waves from the arrangement between devices and peripheral devices. Countermeasures are essential.

  Usually, when audio signals are transmitted and received by wireless communication, even if a part of the audio signal is missing and the audio of that part is not reproduced, there is little discomfort, for example, a cordless telephone that communicates the audio signal wirelessly, etc. A special retransmission control is not performed for reception errors, and a mechanism for muting the sound of the error part is devised so that the deterioration of the sound quality when a reception error occurs is not noticeable.

  On the other hand, in the case of image data, even if a reception error occurs and a part of the image data is lost, the quality of the image may be greatly deteriorated. Image data retransmission control is performed. That is, when a reception error occurs, the reception side requests retransmission of the data with the reception error, and the transmission side retransmits the corresponding data in response to the retransmission request, thereby degrading communication quality due to the occurrence of the reception error. (Data missing) is eliminated.

  In addition, in devices such as door phones and security cameras that simultaneously transmit image and audio data by wireless communication, in order to compensate for transmission of image and audio data in real time, the reduction in effective communication rate due to the above-mentioned retransmission is considered. Thus, the transmission rate of the image and audio data is set lower than the communication rate in the wireless section. In order to prevent the effective communication rate from falling below the transmission rate of image and audio data when retransmission control due to an unforeseen reception error occurs, the occurrence status of reception errors and reception Depending on the communication state such as electric field strength, the number of retransmissions of error data is limited and the transmission rate of image and audio data is controlled.

  For example, as a method of controlling the number of retransmissions of error data and the transmission rate control of image and audio data (Patent Document 1), when the communication state is good, the number of retransmission restrictions is reduced and the image and audio data are reduced. When the transmission condition deteriorates with low compression and the transmission rate of image and audio data is deteriorated, the number of retransmissions is increased and the image and audio data are highly compressed and the transmission rate of image and audio data is increased. A method is disclosed in which the transmission rate of image and audio data is controlled not to be smaller than the effective transmission rate in the wireless section due to a change in the communication state by performing transmission at a low value.

  In addition, there is a method of suppressing deterioration of communication quality at the time of reception error by using an error correction code in an apparatus that performs wireless communication of image and audio data simultaneously. This method simultaneously transmits error detection / correction codes together with audio and image data to be transmitted, and if a reception error is detected, normal data is estimated based on the received data and the correction code. It is a method of doing. In this method, the correction capability improves as the ratio of the correction code to the actual data increases, but there is a problem that the effective communication rate decreases. As a method for solving this problem, in Patent Document 2, an error correction code is not added to each of video / audio, but an error correction code is added only to image data, that is, video signal data. A method of controlling an audio signal according to an error state of signal data is disclosed.

A method for improving communication quality by establishing a plurality of wireless links and sending transmission data a plurality of times is disclosed in (Patent Document 3). In (Patent Document 3), in the communication in which the time axis is equally divided and the time division multiplexing is performed in each slot obtained by dividing the divided fixed time into N, the first wireless link transmitted and received every N slots and the first Using the second radio link that is transmitted and received every N slots in a slot different from the radio link, the same data is transmitted on the first radio link and the second radio link, and the data that can be received correctly on the receiving side The communication quality of data communication is improved by selecting and performing reception processing.
Japanese Patent Laying-Open No. 2005-6288 JP-A-10-136319 Special table 2003-500595 gazette

  However, in a conventional wireless communication apparatus, when a reception error occurs due to retransmission control, it is necessary to retransmit data for which a retransmission request has been received on the transmission side. It is necessary to hold the data, and a storage unit such as a large RAM is required on the transmission side device, and complicated control for retransmission control for reception error data is required on each transmission side reception side, and control is performed. The load on the control unit such as a microcomputer was heavy.

  In addition, countermeasures for the occurrence of a reception error using an error correction code include the problem that the effective rate is slow even when no reception error has occurred, and the processing load for error correction is large, such as a microcomputer that performs arithmetic processing. The load was great.

  Also, the method of improving communication quality by sending the same data multiple times using multiple radio links requires negotiations to increase or decrease the radio links, so the load on the control unit such as a microcomputer that performs control There is no radio resource for establishing the second radio link, and a problem that causes a decrease in radio resources capable of simultaneous communication because a plurality of communication links are always activated to improve communication quality. And the problem that the upper limit of the number of transmissions is limited to the number of slots that can be multiplexed within a certain period of time divided, so that the effect of improving communication quality is limited by the configuration of time division multiplexing, When transmitting the same data to other communication partners, it is necessary to activate the wireless link for each partner, and the load on the control unit such as a microcomputer that performs further control is heavy. Kunar and at the same time there has been a problem that restricted the radio resources.

  In view of the above problems, the present invention reduces the occurrence of data loss due to a reception error during wireless communication with a simple circuit and control, and effectively uses wireless resources to simultaneously deal with a plurality of partners. It is an object of the present invention to provide a wireless communication system capable of data transmission and capable of data transmission at an optimum communication rate corresponding to wireless communication quality and a communication method thereof.

  The present invention is a wireless communication system for performing one-way data communication from a first wireless communication device to a second wireless communication device, wherein the second wireless communication device performs first communication by the one-way data communication. Received data selection means for selecting only new received data from data sent from the wireless communication device and sequentially received, and reception status detection means for detecting a reception status in data communication with the first wireless communication device And the first wireless communication device is notified from the second wireless communication device, and the first wireless communication device is notified of the reception state detected by the reception state detecting means. Data transmission processing means for determining the number of times of data transmission based on the received reception state, the data transmission processing means increases the number of times of data transmission when notified of the deterioration of the reception state, the deterioration of the reception state It is characterized in that it works to reduce the number of times to transmit and it is notified not.

  The wireless communication system and communication method according to the present invention allows the second wireless communication device to transmit data from the first wireless communication device (for example, a door phone parent device) to the second wireless communication device (for example, a doorless cordless child device). The number of times the same data is transmitted is determined in accordance with the reception state notified from the communication device, and the second wireless communication device starts a new transmission from the data sequentially received from the first wireless communication device. By transmitting / receiving data so that only received data is selected, the first wireless communication device on the transmission side retransmits the transmitted data in response to a retransmission request from the second wireless communication device on the reception side. Therefore, there is no need to hold data for which transmission has been completed for a certain period of time in preparation for a retransmission request, and a storage unit such as a RAM is not required or the capacity can be reduced. In addition, there is no need for complicated control for retransmission control for received error data and calculation processing for error correction using an error correction code, and the microcomputer performs control in both the first wireless communication device and the second wireless communication device. Thus, the load on the control unit can be reduced. Also, compared to the case where communication quality is improved by adding an error correction code, there is less data to be added besides the actual data to be transmitted, and it is possible to suppress a decrease in effective rate when the communication state is good. .

  In addition, the wireless communication system and the communication method of the present invention perform data transmission by one-way wireless communication that does not require negotiation for the wireless link, so even if there are a plurality of transmission partners, negotiation for the wireless link is performed. Therefore, it is possible to reduce the load on the control unit, and to simultaneously transmit high-quality data to a plurality of partners without increasing the radio resources to be used.

  In addition, since the wireless communication system and the communication system of the present invention transmit the same data as many times as the communication state within the usable wireless resources, there is even one wireless resource (communication slot) that can be used. Alternatively, even when multiplex communication is not performed, it is possible to suppress a decrease in communication quality of data transmission to a plurality of other parties at the same time.

  The present invention reduces the occurrence of data loss due to reception errors during wireless communication with a simple circuit and control, and can effectively transmit data to a plurality of other parties at the same time by effectively using wireless resources. No wireless link negotiation is required from the first wireless communication device to the second wireless communication device for the purpose of providing a wireless communication system and communication method capable of transmitting data at an optimal communication rate according to the communication quality of the first wireless communication device. Data transmission is performed using one-way wireless communication, and the number of times the same data is transmitted is determined according to the reception state notified from the second wireless communication device. The second wireless communication device This was realized by transmitting / receiving data so that only new received data is selected from data sent from the wireless communication device and sequentially received.

  A first invention made to solve the above problems is a wireless communication system that performs one-way data communication from a first wireless communication device to a second wireless communication device, wherein the second wireless communication device Detecting a reception state in data communication between the first wireless communication device and reception data selection means for selecting only new reception data from among the data sent from the first wireless communication device and sequentially received. A reception state detection unit, and operates to notify the first wireless communication device of the reception state detected by the reception state detection unit. The first wireless communication device is notified from the second wireless communication device. Data transmission processing means for determining the number of times of data transmission based on the received reception state, the data transmission processing means increases the number of times of data transmission when notified of the deterioration of the reception state, and recovers the deterioration of the reception state What you did When notified, it operates so as to reduce the number of times of transmission. When data is transmitted from the first wireless communication apparatus to the second wireless communication apparatus, notification is sent from the second wireless communication apparatus. The number of times the same data is transmitted is determined according to the received state, and the second wireless communication device receives only new received data from the data transmitted from the first wireless communication device and sequentially received. By transmitting and receiving data as selected, the first wireless communication apparatus on the transmission side does not need to retransmit the transmitted data in response to a retransmission request from the second wireless communication apparatus on the reception side. Therefore, there is no need to hold data for which transmission has been completed in preparation for a retransmission request for a certain period of time, and there is an effect that a storage unit such as a RAM is unnecessary or the capacity can be reduced. In addition, there is no need for complicated control for retransmission control for received error data and calculation processing for error correction using an error correction code, and the microcomputer performs control in both the first wireless communication device and the second wireless communication device. Thus, the load on the control unit can be reduced. Also, compared to the case where communication quality is improved by adding an error correction code, there is less data to be added besides the actual data to be transmitted, and it is possible to suppress a decrease in effective rate when the communication state is good. . In addition, since data transmission is performed by one-way wireless communication that does not require negotiation for the wireless link, control for negotiation for the wireless link becomes unnecessary even if there are multiple transmission partners. The effect is that the load can be reduced, and the effect that high-quality data transmission to a plurality of partners can be performed simultaneously without increasing the radio resources to be used. In addition, since the same data is transmitted as many times as the number of available radio resources according to the communication state, there is only one radio resource (communication slot) that can be used or no multiplex communication. However, there is an effect that it is possible to suppress a decrease in communication quality of data transmission to a plurality of partners at the same time.

  In addition, since the reception state detection means detects the reception electric field strength of the data transmitted from the first wireless communication device, the physical distance between the first wireless communication device and the second wireless communication device is increased. Optimum according to the received electric field strength of the second wireless communication device, such as a decrease in the joint received electric field due to the decrease in the received electric field strength due to an obstacle between the first wireless communication device and the second wireless communication device Data transmission can be performed by determining the number of transmissions, and even when the received electric field strength decreases, the deterioration of communication quality can be reduced, and there is an effect that optimal data transmission can be controlled in accordance with changes in the received electric field strength.

  In addition, since the reception state detection means detects the state of occurrence of a reception error in the data transmitted from the first wireless communication device, the reception due to the deterioration of the received electric field strength or the interference wave emitted from another device. Data transmission is possible by determining the optimal number of transmissions according to the error occurrence state, and it is possible to reduce deterioration in communication quality even in environments where the received electric field strength has deteriorated or where there are interference waves that affect communication quality. Thus, there is an effect that it is possible to control the optimum data transmission according to the change in the occurrence state of the reception error.

  Further, since the reception state detecting means detects the interruption of continuity of the received data of the data transmitted from the first wireless communication device, the reception data detection means is in a state of occurrence of the interruption of continuity of the reception data caused by some factor. Therefore, it is possible to determine the optimal number of transmissions and transmit data, reduce communication quality deterioration regardless of the cause of reception error, and optimal data transmission according to changes in the state of interruption of received data continuity It is possible to control this.

  Further, the reception state detecting means transmits the reception electric field strength of the data transmitted from the first wireless communication device, the occurrence state of the reception error of the data transmitted from the first wireless communication device, or the transmission from the first wireless communication device. By detecting any two or more of discontinuities in the continuity of the received data, the physical distance between the first wireless communication device and the second wireless communication device, the presence or absence of an obstacle, It is possible to detect the deterioration of communication quality caused by various factors such as the occurrence of jamming waves and combine the control of the number of transmissions for each deterioration factor of communication quality to determine the more suitable number of transmissions suitable for the wireless environment. There is an effect that it is possible to control the optimal data transmission in accordance with the change of.

  According to a second aspect of the present invention, in the reception state detection means according to the first aspect of the present invention, the data error detection means for detecting presence / absence of missing reception data and reception quality detection means for detecting the radio quality of the reception signal are provided. The second wireless communication apparatus operates to notify the first wireless communication apparatus of the presence or absence of reception data detected by the data error detection means and the reception quality detection means and the reception quality. Is provided with data transmission processing means for determining the number of times of data transmission based on the presence or absence of reception data and reception quality notified from the second wireless communication device, the data transmission processing means, Alternatively, the number of times of data transmission is increased when the reception quality deterioration is notified, and the number of transmissions is decreased based on the notified reception quality when notification of no missing reception data is received. It is designed to operate, and when reception data loss occurs, the number of transmissions can be increased immediately to suppress deterioration in communication quality, so the effect of reducing reception data loss with good responsiveness even if the communication environment changes Have In addition, when reception quality deteriorates, the number of transmissions can be increased and communication quality deterioration can be suppressed, so that even if reception quality deteriorates, reception data can be prevented from being lost in advance, and communication quality deterioration can be reduced. In addition, since the number of transmissions is reduced when the reception quality is recovered without any missing reception data, the number of transmissions is reduced by mistake, so there is less risk of reception data loss, so even if the communication environment changes There is an effect that it is possible to select the optimum number of transmissions while reducing the loss of received data.

  Further, since the reception quality detection means detects the reception electric field strength of the data transmitted from the first wireless communication device, the physical distance between the first wireless communication device and the second wireless communication device. Optimum according to the received electric field strength of the second wireless communication device, such as a decrease in the received electric field joint strength caused by the interference and a decrease in the received electric field strength caused by an obstacle between the first wireless communication device and the second wireless communication device Thus, it is possible to determine the number of transmissions and perform data transmission. Even when the received electric field strength decreases, it is possible to reduce the deterioration of communication quality and to control optimal data transmission according to the change in received electric field strength.

  Further, the reception quality detection means detects the occurrence state of the reception error of the data transmitted from the first wireless communication device, so that the reception due to the deterioration of the received electric field strength or the interference wave emitted from another device. Data transmission is possible by determining the optimal number of transmissions according to the error occurrence state, and it is possible to reduce deterioration in communication quality even in environments where the received electric field strength has deteriorated or where there are interference waves that affect communication quality. Thus, there is an effect that it is possible to control the optimum data transmission according to the change in the occurrence state of the reception error.

  Further, the reception state detecting means in the second invention detects the reception electric field strength of the data transmitted from the first wireless communication device and the occurrence state of the reception error of the data transmitted from the first wireless communication device. By doing so, the communication quality is detected by detecting deterioration in communication quality caused by various factors such as the physical distance between the first wireless communication device and the second wireless communication device, the presence or absence of an obstacle, and the occurrence of an interference wave. By combining the control of the number of transmissions for each degradation factor, it is possible to determine a more suitable number of transmissions suitable for the wireless environment, and it is possible to control optimal data transmission according to changes in the wireless environment.

  In addition to the above-described configuration, the first wireless communication apparatus includes a dividing unit that divides transmission data into predetermined lengths, and a sequence number assignment that assigns a sequence number to each transmission data divided by the dividing unit. The reception data selection means selects new reception data based on the sequence number, and the reception status detection means or the data error detection means detects the presence or absence of reception data based on the sequence number. As a result, the unnecessary additional information required for communication control is reduced to only the sequence number, and the effect of reducing the effective rate due to the additional information required for communication control can be reduced. Further, by monitoring the sequence number, new data can be selected, that is, congestion data can be discarded, and the lack of received data can be determined, thereby reducing the processing burden associated with communication control.

  According to a third aspect of the present invention, in the wireless communication system including the first wireless communication device and the second wireless communication device, when the one-way data communication is performed from the first wireless communication device to the second wireless communication device. At the same time, communication is performed using a multiplexing method that performs bidirectional wireless communication between the first wireless communication device and the second wireless communication device, and the reception state detected by the reception state detection means is set to the first state. When notifying the wireless communication device, a transmission signal from the second wireless communication device to the first wireless communication device in the bidirectional wireless communication between the first wireless communication device and the second wireless communication device is used. As a result, the control for notifying the reception state of the one-way wireless communication can be performed by transmitting the reception state of the one-way wireless communication using the transmission signal of the two-way wireless communication established separately. Has the effect of being simple. In addition, there is no need to secure a new radio resource in order to notify the reception state of the one-way wireless communication, and it is possible to prevent the reception state from being unable to be notified due to a shortage of wireless resources.

  Furthermore, in the bidirectional wireless communication between the first wireless communication device and the second wireless communication device, the data string transmitted in one section that is self-division multiplexed is a control data field for transmitting a control signal. An information data field for transmitting an information signal is included, and the reception state detected by the reception state detection means is transmitted in the control data field, so that the reception state of one-way wireless communication is established separately. It is possible to notify the reception state of one-way wireless communication without affecting the wireless communication in the information field of two-way wireless communication by transmitting using the control field of the transmission signal of two-way wireless communication It has the effect. Further, by incorporating control for compensating the delivery of control data transmitted in the control field of the transmission signal for bidirectional wireless communication, it becomes possible to reliably notify the reception state of one-way wireless communication. Has an effect.

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

  FIG. 1 is a block diagram of a door phone that performs image transmission using the wireless communication system according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram showing a TDMA frame and slot configuration in the wireless communication system according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of a format of a data string communicated in the wireless communication system according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram illustrating an operation of dividing and transmitting image information in the wireless communication system according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram for explaining the operation of the door phone that performs image transmission using the wireless communication system according to the first embodiment of the present invention.

  Hereafter, each functional block of the door phone of Embodiment 1 comprised with the radio | wireless communications system of this invention is demonstrated using FIG.

  In FIG. 1, 100 is an entrance cordless handset. In the entrance device 100, 101 is a camera unit that captures an image and outputs a video signal, 102 is composed of a microphone, a speaker, an amplifier, etc., and outputs an audio signal from the speaker, and also amplifies the input signal from the microphone and visits A call unit for outputting a voice signal of a person, 103 is a call button for notifying a visitor of a visitor and a call detection unit configured by a circuit for generating a notification signal when the call button is pressed, 104 is a video This is a demultiplexing circuit that synthesizes a signal, a voice signal, and a notification signal and outputs the synthesized signal to the doorphone master unit 200 and also separates the voice signal from the doorphone master unit 200 and outputs it to the call unit 102.

  Reference numeral 200 denotes a master unit. In the parent device 200, 220 is a demultiplexing circuit that separates the video signal, the audio signal, and the notification signal from the entrance slave device 100 and outputs them to each unit, and outputs the audio signal from the master device 200 to the entrance slave device 100; 201 is a monitor circuit that outputs the video signal from the entrance cordless handset 100 separated and output by the demultiplexing circuit 220 to the monitor 202, and also converts the video signal into digital information and outputs it as image information. 202 is a monitor that displays the video signal. , 203 is a digitally converted video signal output from the monitor circuit 201, that is, an image information storage unit for storing image information, and 204 is a notification signal received from the entrance cordless handset 100 that is separated and output by the demultiplexing circuit 220. The control unit 214 is notified and a call detection unit that activates the notification unit 205, 205 is a notification unit that sounds a notification sound for notifying a visitor, 206 The audio signal from the entrance slave unit 100 separated and output by the demultiplexing circuit 220 is output to the call unit 207, the audio signal from the call unit 207 is output to the demultiplexing circuit, and the audio signal from the entrance unit 100 is also output. Is converted into digital information and output as audio information, and audio information sent from the cordless handset 300 is converted into analog data and output to the demultiplexing circuit 220. Reference numeral 207 is an audio signal including a microphone, a speaker, an amplifier, and the like. Is output from a speaker, and a voice communication unit that amplifies an input signal from a microphone and outputs a voice signal; 208, a response button that activates a response operation when responding to a visitor in the main unit 200; 209, voice information; A synchronization signal necessary for time division multiplex communication (hereinafter referred to as TDMA) and an error detection code for error detection are added to image information, control signals, etc. A transmission data sequence is generated in accordance with the frame and time slot, and error detection processing is performed in accordance with the TDMA frame and time slot from the received reception data sequence. A frame processing unit 210 for outputting audio information and control signals modulates and amplifies an input data sequence, and amplifies and demodulates a received radio signal to output received data (hereinafter referred to as TDMA). A wireless unit that performs wireless transmission and reception, 213 an antenna, 214 a dividing unit that divides the image information stored in the image information storage unit 203 into a predetermined length, and a sequence number for each divided image information And a reception number (hereinafter referred to as a reception state) of reception data that are notified from a cordless handset 300 to be described later. The data transmission processing means for determining the number of times of transmission of the image information divided based on the information), control of each unit for transmitting the image information to the cordless slave unit, and a visitor by the master unit 200 It is a control part which performs control of the whole main | base station 200, such as control of each part at the time of responding to.

  Reference numeral 300 denotes a cordless slave unit. In the cordless handset 300, reference numeral 301 denotes a notification unit that sounds a notification sound for notifying a visitor. An audio circuit 302 converts the audio information from the parent device 200 into an analog signal and outputs it to the call unit 207, and converts the audio signal sent from the call unit 207 into a digital signal and outputs it to the frame processing unit 306. A call unit 303 includes a microphone, a speaker, an amplifier, and the like, outputs a voice signal from the speaker, and amplifies an input signal from the microphone and outputs a voice signal. A monitor circuit 304 generates and outputs a video signal based on image information and error information from the master device 200, and a monitor 305 displays the video signal.

  306 outputs image information, audio information, and control signals received in a time slot in which no error has occurred, and also transmits synchronization information necessary for TDMA communication and error detection codes for error detection to audio information and control signals to be transmitted. Is a frame processing unit that generates a transmission data string in accordance with a TDMA frame and a time slot. The frame processing unit 306 also operates as one of reception state detection means and reception quality detection means, performs error detection processing from the received data sequence in accordance with TDMA frames and time slots, and determines the radio quality of the received signal. Detect.

  Reference numeral 307 denotes a wireless unit that performs TDMA wireless transmission / reception that modulates and amplifies an input data string, amplifies and demodulates a received wireless signal, and outputs received data. Reference numeral 310 denotes a response button for notifying activation of a response operation or call termination when responding to a visitor with the cordless handset 300. A control unit 311 performs overall control of the cordless slave device 300. The control unit 311 discards image information received redundantly based on the sequence number given to the received image information, and outputs received image information to the monitor circuit 304 without the redundant image information. In addition, a detection operation as a data error detection means for detecting the presence or absence of image information, which is one of the reception state detection means, is performed. In addition, the control unit 311 operates to notify the base unit 200 of reception state information for notifying the presence or absence of reception data and reception quality, and receiving image information, audio information, and the like transmitted from the base unit 200. Control of each part for performing the response and control of each part when responding to the visitor with the cordless handset 300.

  An external view of the entrance cordless handset 100 is shown in FIG. On the front surface of the entrance cordless handset, a camera lens 1201 (camera unit 101) for imaging the visitor, a microphone 1202 and a speaker 1203 (call unit 102) for making a call with the visitor, A call button 1204 (call detection unit 103) that informs the cordless handset 300 of a visit is arranged.

  An external view of the parent device 200 is shown in FIG. An LCD panel 1020 (monitor 202) that displays an image of a visitor of the front door slave device 100, a response button 208, and an LED 1017 that displays the visit with light are arranged on the front surface of the parent device 200. Moreover, it has the microphone 1015 and the speaker 1016 (call part 102) for calling with the visitor of the entrance cordless handset 100.

  An external view of the cordless handset 300 is shown in FIG. On the front of the cordless handset 300, there is an LCD panel 1107 (monitor 305) that displays an image of a visitor of the entrance handset 100, a response button 310, and an LED 1108 (notification unit 301) that displays the visit with light. Moreover, it has a microphone 1110 for making a call with a visitor of the entrance cordless handset 100, and a speaker 1111 on the back of the cordless handset 300.

  With this configuration, a visitor can talk with a user in the room using the entrance cordless handset 100. Here, the image of the entrance cordless handset is sent to the cordless cordless handset 300 via the base phone 200 having the door phone interface 1001, and the entrance cord on the LCD panel 1107 of the cordless cordless handset 300 carried by the user in the room. The image of the plane is projected and you can talk while watching the visitors. In addition, users in the room can talk while moving with the cordless handset 300. Further, the cordless handset 300 can be placed in a convenient place during standby.

  Next, the operation of the above door phone will be described. When a visitor presses a call button provided in the call detection unit 103 of the front door device 100, a notification signal is output from the call detection unit 103 and output to the parent device 200 via the demultiplexing circuit 104. In master device 200, the notification signal from entrance slave device 100 is output from demultiplexing circuit 220 to call detection unit 204. Then, the call detection unit 204 activates the notification unit 205, and a notification sound for notifying a visitor is output from the notification unit 205. In addition, when the call detection unit 204 receives the notification signal, the call detection unit 204 notifies the control unit 214 that the call button of the call detection unit 103 of the front door device 100 has been pressed. Then, the control unit 214 starts control for transmitting notification information for notifying the cordless handset 300 of the call activation and the start of transmission of image information.

  Cordless handset 300 operates as a subordinate station of base unit 200 and normally operates to receive a control signal of base unit 200, receives notification information from base unit 200, and controls unit 311. , The control unit 311 activates the notification unit 301, and a notification sound for notifying a visitor is output from the notification unit 301. In addition, when the call button of the entrance slave device 100 is pressed, the master device 200 and the cordless slave device 300 are notified that the call button described above has been pressed, and a notification sound is generated by the notification unit 205 and the notification unit 301, respectively. At the same time, control is performed so that a video signal photographed by the camera unit 101 of the entrance slave device 100 is sent to the master device 200 and the cordless slave device 300 and displayed on the monitor 202 and the monitor 305, respectively. It is.

  A video signal photographed by the camera unit 101 of the front door device 100 is sent to the demultiplexing circuit 104 and output to the parent device 200. The video signal sent from the entrance slave unit 100 is output from the demultiplexing circuit 220 to the monitor circuit 201, and the monitor circuit 201 outputs the video signal to the monitor 202, and the monitor 202 uses the camera unit 101 of the entrance slave unit 100. The video being shot is displayed. Further, the control unit 214 of the parent device 200 requests the image storage unit 203 to start image data accumulation in parallel with the control for transmitting the notification information to the cordless child device 300 described above.

  When receiving a request to start image data accumulation, the image storage unit 203 requests the monitor circuit 201 to output image information, and stores the image information output from the monitor circuit 201. In response to an output request for image information, the monitor circuit 201 digitally converts a signal for one screen of the video signal sent from the entrance slave device 100 and outputs the converted signal to the image storage unit 203 as image information.

  When the image storage unit 203 stores the image information for one screen output from the monitor circuit 201, the image storage unit 203 outputs a storage end notification to the control unit 214. Upon receiving a notification of the end of accumulation, the control unit 214 sequentially reads the image information stored in the image information storage unit 203 into data lengths that can be transmitted in one slot, and reads the divided image for one slot that has been read. Control is performed so that the information is transmitted a predetermined number of times in a predetermined time slot. On the other hand, when receiving the broadcast information, the control unit 311 of the cordless slave device 300 controls the radio unit 307 and the frame processing unit 209 so as to receive a predetermined time slot, and the image sent from the master device 200 is received. Receive information. When the control unit 311 receives the image information from the parent device 200, the control unit 311 outputs the received image information to the monitor circuit 304 except for the divided image information received redundantly. The information is converted to analog and output to the monitor 305, and the image sent from the parent device 200 is displayed on the monitor 305.

  Further, when the base unit control unit 214 transmits the image information for one screen stored in the image information storage unit 203, it performs the above-described operation, that is, the image data storage start request, and the image information accordingly. Is updated, and control is performed so as to repeat the operation of transmitting new image information to the cordless handset 300. At this time, the control unit 214 can also transmit the notification information for notifying the start of transmission of image information every time transmission of image information for one new screen is started.

  Next, the response operation will be described. When the response button 208 of the parent device 200 is pressed and detected by the control unit 214, the control unit 214 activates the voice circuit 206 so that voice communication between the front door device 100 and the parent device 200 becomes possible. Take control. That is, the sound input from the microphone of the call unit 102 of the front door device 100 is output from the speaker of the call unit 207 of the base unit 200, and the sound input from the microphone of the call unit 207 of the base unit 200 is Control is performed to output from the speaker of the communication unit 102 of the device 100.

  In addition, when the response button 310 of the cordless handset 300 is pressed and detected by the control unit 311, the control unit 311 activates the voice circuit 302 and can perform a voice call between the entrance handset 100 and the cordless handset 300. Control is performed so as to be in a state. That is, the control unit 311 first activates a bidirectional wireless link, starts bidirectional communication with the parent device 200, and sets the voice path of the parent device 200. Then, the voice input from the microphone of the call unit 303 of the cordless handset 300 is digitally converted by the voice circuit 302, output to the frame processing unit 306, transmitted to the base unit 200 wirelessly, and the frame processing unit 306. Is output to the audio circuit 302, converted into an analog signal, and controlled so as to be output from the speaker of the calling unit 303. On the other hand, when the bidirectional wireless link with the cordless slave device 300 is activated and the bidirectional communication with the cordless slave device 300 is started, the control unit 214 of the master device 200 receives the voice sent from the entrance slave device 100. The signal is digitally converted by the audio circuit 206 and output to the frame processing unit 209, wirelessly transmitted to the cordless handset 300, and the audio information output from the frame processing unit 209 is output to the audio circuit 206 and analog After the conversion, the demultiplexing path 201 is met and sent to the entrance unit 100, and control is performed so that the signal is output from the speaker of the communication unit 102 of the entrance unit 100.

  Next, wireless communication control between the parent device 200 and the cordless child device 300 will be described. Here, as TDMA control, when one frame is divided into eight time slots and bidirectional wireless communication is performed between the parent device 200 operating as a control station and the cordless child device 300 operating as a subordinate station, An example in which transmission to the cordless handset 300 is performed in the first half of the frame (time slots 1 to 4) and transmission from the cordless handset 300 to the base unit 200 is performed in the second half of the frame (time slots 5 to 8). To do. The time slot used for transmission / reception of image information includes a time slot in which the base unit 200 transmits a control signal and a time slot in which the control signal is transmitted, and a predetermined positional relationship, that is, a time slot in which the control signal is transmitted. An example in which transmission is performed in two time slots of four time slots apart from each other is shown.

  The states of the base unit 200 operating as a control station and the cordless slave unit 300 operating as a subordinate station are the image communication state in which image information is transmitted from the master unit 200 to the cordless slave unit 300, and the master unit 200 and the cordless slave unit. There are three states: a voice communication state in which 300 performs bidirectional wireless communication and transmits and receives voice signals, and other idle states.

  First, the operation in the idle state will be described. In the idle state, base unit 200 transmits a control signal in a specific time slot in the frame. FIG. 2 shows an example of the configuration of the time slot in the first embodiment. In this example, an example in which the control signal for each frame is transmitted in the time slot 1 is shown. FIG. 3 shows an example of a format of a data string transmitted in each time slot, and FIG. 3A shows an example of a format used in a time slot for transmitting a control signal. That is, in this example, base unit 200 transmits a control signal in slot 1 of each frame by placing it in the control data field of FIG. The control signal transmitted here includes the identification information of the master unit and the number of the transmission slot used for transmitting the control signal. The control unit 214 outputs a control signal to the frame processing unit 209 in accordance with the timing of the transmission slot of the control signal, and the frame processing unit 209 adds a synchronization signal and an error detection signal to the control signal and transmits them to the radio unit. Output. The error detection signal is described in the CRC1 field of FIG. 3A, and an error detection code string (for example, CRC code) generated from the control signal transmitted in the control data field is used. In addition, the control unit 214 sets the transmission frequency of the wireless unit 210 in accordance with the transmission timing of the control signal.

  Next, reception control of the idle base device 200 will be described. Master device 200 receives a call from cordless slave device 300 in a time slot other than the time slot for transmitting a control signal in the latter half of the frame. The control unit 214 sets the reception frequency of the radio unit 210 in accordance with the timing of the received time slot. When a call from the cordless handset 300 is received and the received data is output to the frame processing unit 209, the frame processing unit 209 controls the control signal in the control data field and the error detection based on the synchronization signal. The signal is separated, and the error determination of the control signal is performed based on the received error detection signal. When it is determined that the signal is normally received, the received control signal is notified to the control unit 214. The example of FIG. 2 shows an example in which reception is performed in time slots 6 to 8 of each frame.

  Next, control of the cordless cordless handset 300 in the idle state will be described. Since cordless handset 300 receives the control signal of base unit 200, cordless handset 300 continuously receives the frequency at which base unit 200 is transmitting the control signal, and performs a supplementary operation of base unit 200. When the control signal of the parent device is received by continuous reception, the reception is sequentially performed for each frame thereafter, and the control signal of the parent device is continuously received. And the number information of the transmission slot used for transmission of the control signal included in the control signal of the parent device is received, and the synchronization of the frame and time slot with the parent device is established. That is, the control unit 311 performs control so that the wireless unit 307 is continuously received at the transmission frequency of the control signal transmitted by the parent device 200. The reception data string received and demodulated by the radio unit 307 is output to the frame processing unit 306. The frame processing unit 306 detects the synchronization signal included in the received data string. When the synchronization signal is detected, the control signal in the control data field is separated from the error detection signal based on the synchronization signal. Then, the control signal error is determined based on the received error detection signal, and when it is determined that the signal is normally received, the control unit 311 is notified of the received control signal.

  Based on the identification information of the parent device included in the control signal, the control unit 311 determines whether or not the parent device is waiting. If the parent device is waiting, the control unit 311 shifts to an intermittent reception operation for each frame. Control is performed. That is, the control unit 311 controls the radio unit 307 so as to perform reception in accordance with the timing of the time slot in which the control signal of the base unit has been received first. When the number of the transmission slot used for transmission of the control signal included in the control signal transmitted by the parent device 200 is received, synchronization between the parent device 200 and the time slot is established.

  Next, the operation in the image communication state will be described. When the call detection unit 204 notifies that the call button of the call detection unit 103 of the front door device 100 has been pressed, the control unit 214 of the parent device 200 shifts the operation from the idle state to the image communication state. Start control. The control unit 214 outputs, to the frame processing unit 209, a control signal (hereinafter referred to as broadcast information) for notifying the calling and the start of image information transmission in accordance with the timing of the time slot for transmitting the control signal. Then, transmission of the image information is started from the next frame in which the notification information is transmitted. The image information is transmitted in the time slot corresponding to the time slot that transmits the control signal and the time slot that transmits the control signal. For example, when the control signal is transmitted in time slot 1 as shown in FIG. 2, the image information is transmitted in time slot 1 and time slot 5. At this time, in time slot 1, the format of the transmission data string is changed so that the control signal and the image information are transmitted simultaneously.

  FIG. 3B shows an example of a format when transmitting image information. In this example, the image information is transmitted in the information data field. In addition, a new error detection code is added as error detection data in the information data field for transmitting image information. (In FIG. 3B, it is described as CRC2.) Also, the format of the transmission data string used for communication in the time slot (time slot 5) corresponding to the time slot (time slot 1) for transmitting the control signal is the same. The format shown in FIG. 3B is used, and image information is transmitted in the information data field.

  The control unit 214 reads the image information stored in the image storage unit 203 while dividing the image information into data lengths that can be transmitted in one time slot, and sets the same sequence number for the divided image information a predetermined number of times. And control to perform retransmission. The frame processing unit 209 matches the transmission timing so that the sequence number and the divided image information are transmitted in the information data field of the time slot corresponding to the time slot for transmitting the control signal and the time slot for transmitting the control signal, respectively. Is output. The frame processing unit 209 adds an error detection code (CRC2) based on the data sequence of the information data field, generates a data sequence in the format of FIG. 3B, and outputs the data sequence to the radio unit 210. Then, the radio unit 210 transmits the divided image information and the like for each time slot in accordance with the control from the control unit 214.

  On the other hand, the control unit 311 of the cordless child device 300 notifies the user that the call button of the call detection unit 103 of the entrance child device 100 has been pressed and transmits notification information for notifying the start of transmission of image information. When received, control is started to shift the operation from the idle state to the image communication state.

  Cordless handset 300 is in a receiving state in synchronization with base unit 200 in the idle state, receiving a time slot in which base unit 200 transmits a control signal, and time when base unit 200 transmits a control signal. When broadcast information is transmitted in the slot, a data sequence including the broadcast information is received and demodulated by the radio unit 307 and output to the frame processing unit 306. The frame processing unit 306 separates the control data field based on the synchronization signal included in the received data sequence, and notifies the control unit 311 of it. Since the control unit 311 analyzes the data string of the notified control data field and receives the image information transmitted from the parent device 200 from the next frame in the case of broadcast information, the control unit 311 already receives the control signal. In addition to the time slot that receives the control signal, the control of the wireless unit 307 is started so as to start the reception of the time slot corresponding to the time slot that is receiving the control signal.

  Thus, the cordless handset 300 that has received the broadcast information is in a state in which it can receive the image information sent from the base unit 200 in the time slot corresponding to the time slot that receives the control signal and the time slot that receives the control signal. become. Then, when the signal including the image information transmitted from the parent device 200 is received and demodulated by the wireless unit 307 and output to the frame processing unit 306, the frame processing unit 306 uses the synchronization signal included in the received data sequence as a source. The data of the information data field and the error detection code (CRC2) of the information data field are separated, and the presence or absence of a reception error in the information data field is analyzed based on the error detection code (CRC2). If it is, the data in the information data field is output to the control unit 311.

  When the control unit 311 receives the data in the information data field, that is, the image information divided into the sequence numbers, the control unit 311 analyzes whether or not the image information has been received in duplicate based on the sequence numbers. If it is information, the image information is output to the monitor circuit 304 and the image is displayed on the monitor 305.

  In addition, when the sequence number assigned to the received divided image information is lost, the control unit 311 discards all received data including the same divided image information that has been retransmitted due to a reception error. Assuming that the image information is missing, error information is output to the monitor circuit 304, and the monitor circuit 304 complements the missing image information to display the monitor 305. For example, when the image information transmitted from the master unit is well-known bitmap data, the control unit 311 calculates the number of missing time slots based on the received sequence number, and the missing time slot. The number of lost image information data is calculated based on the number and the communication format, and the number of lost image information data is notified to the monitor circuit 304 along with the error information. Correction is performed so that pixel information corresponding to the number of data is displayed in black, and control is performed so that the image displayed on the monitor 305 is not shifted due to lack of image information.

  Next, how the image information is divided and transmitted will be described with reference to FIG. When base unit 200 transitions from the idle state where only the control signal is transmitted to the image communication state, first, broadcast information is transmitted in the time slot where the control signal was transmitted. In the example of FIG. 4, broadcast information is transmitted in time slot 1 of frame 1. Then, transmission of image information starts from frame 2. In the example of FIG. 4, the image information for one surface is divided into three, D1, D2, and D3, and each is assigned a sequence number of 1 to 3, and transmission is performed three times. . That is, the divided first image information D1 is assigned a sequence number 1, and is transmitted in three time slots of time slot 1 of frame 2, time slot 5 of frame 2, and time slot 1 of frame 3. . Similarly, the divided second image information D2 is assigned a sequence number 2, and is assigned to three time slots of time slot 5 of frame 3, time slot 1 of frame 4 and time slot 5 of frame 4, or The divided third image information D3 is assigned a sequence number 3 and is transmitted in three time slots of time slot 1 of frame 5, time slot 5 of frame 5 and time slot 1 of frame 6, respectively. .

  Next, the operation in the voice communication state will be described.

  When the cordless handset 300 is in the image communication state, when the response button 310 is pressed, the cordless handset 300 starts control to shift to the voice communication state. When the control unit 311 of the cordless slave device 300 detects that the response button 310 is pressed, it selects a time slot other than the time slot that is receiving image information, and starts bidirectional wireless communication with the master device 200. Start control. For example, when cordless handset 300 selects time slot 6, time slot 6 is used for transmission from cordless handset 300 to base unit 200, and time slot 2 is used for transmission from base unit 200 to cordless handset 300. Is used.

  The control unit 311 sets the transmission frequency of the radio unit 307 and outputs a control signal for a radio link activation request to the frame processing unit 306. The frame processing unit 306 generates a transmission data sequence in which the control signal for the radio link activation request is placed in the control data field in the format of FIG. 3B, and outputs the transmission data sequence to the radio unit 307. Sent. Thereafter, in order to communicate with base unit 200, control unit 311 determines the time slot for transmitting the radio link activation request control signal and the reception time slot corresponding to the time slot for transmitting the radio link activation request control signal. Control to send and receive both.

  On the other hand, base unit 200 always receives a reception time slot other than the reception time slot corresponding to the time slot for transmitting an unused control signal, and controls the radio link activation request from cordless slave unit 300. When the data sequence including the signal is transmitted, the radio unit 210 receives and demodulates the data sequence, and outputs it to the frame processing unit 209. The frame processing unit 209 separates the control data field based on the synchronization signal included in the received data sequence, and notifies the control unit 214 of it. The control unit 214 analyzes the data string of the notified control data field, and when the control signal is a wireless link activation request control signal, in order to perform bidirectional communication with the cordless handset 300 from the next frame, Control of the radio unit 210 is started so as to start transmission / reception in the time slot corresponding to the time slot that has received the control signal for the link activation request. Then, control unit 214 outputs a control signal in response to the radio link activation request to frame processing unit 209 in accordance with the timing of the time slot for transmission of the time slot for performing bidirectional wireless communication with cordless slave unit 300. To do.

  The frame processing unit 209 generates a transmission data string in which a control signal for a response to the radio link activation request is placed in the control data field in the format of FIG. 3B, outputs the transmission data sequence to the radio unit 210, and a response to the radio link activation request Control signal is transmitted. In addition, the control unit 214 performs bidirectional communication connection with the cordless handset 300, and at the same time controls the sound circuit 206 to digitally convert the sound signal from the front door device 100 and output it to the frame processing unit 209. Then, control is performed so that the audio signal output from the frame processing unit 209 is converted into an analog signal and output to the entrance unit 100 via the demultiplexing circuit 220. On the other hand, when the cordless handset 300 receives the control signal for the response to the radio link activation request from the base unit 200, the cordless handset 300 similarly sets the voice path, controls the voice circuit 306, and receives the voice signal from the call unit 303. The digital signal is converted and output to the frame processing unit 306, and the audio signal output from the frame processing unit 306 is converted into an analog signal and output to the calling unit 303. Note that the digitally converted audio signal transmitted and received at this time is transmitted and received in the information data field of FIG.

  When the state shifts to the voice communication state and bidirectional wireless communication is established, the control unit 214 of the parent device 200 notifies the frame processing unit 209 of a time slot for performing bidirectional wireless communication, and the frame processing unit 209 The data string of the information data field of the notified time slot is processed as voice information. Similarly, the control unit 311 of the cordless handset 300 notifies the frame processing unit 306 of the time slot for performing bidirectional wireless communication, The frame processing unit 306 operates to process the data string of the notified information data field of the time slot as audio information.

  Next, an operation for shifting from the image communication state to the voice communication state will be described with reference to FIG. FIG. 5 shows a state in which the cordless handset 300 responds and is transmitted / received in the slot 1 and the slot 5 in a state where the base unit 200 transmits the image divided in the slot 1 and the slot 5 by one-way wireless communication. An example is shown in which the parent device 200 and the cordless child device 300 perform wireless communication for two-way audio communication in the slots 2 and 6 while maintaining one-way wireless communication of images.

  In FIG. 5, when a response operation is performed in the cordless slave device 300 (S10), the cordless slave device 300 transmits a control signal for a radio link activation request in the slot 6 (S11). On the other hand, when receiving the radio link activation request control signal (S12), base unit 200 transmits a control signal in response to the radio link activation request in slot 2, which is a transmission slot corresponding to the slot that has received the radio link activation request. Then, the voice path between the entrance slave device 100 and the cordless slave device 300 is set (, S13). When the cordless handset 300 receives a control signal in response to the wireless link activation request, the cordless handset 300 sets a voice path (S14). Thereafter, audio signals are transmitted and received in the slot 2 and the slot 6. In FIG. 5, a one-way wireless communication slot for transmitting image information is indicated by black, and a bidirectional wireless communication slot for transmitting and receiving audio signals is indicated by diagonal lines.

  Next, control of the number of image transmissions will be described. After the response operation is performed, that is, when the two-way wireless communication for voice communication is started, the control unit 311 causes the number of reception errors generated during a predetermined time and the received data It operates to count the number of omissions and notify the base unit 200 of reception state information.

  The number of reception errors is measured based on the detection information of the reception error in the reception slot of the image information detected by the frame processing unit 306. That is, the frame processing unit 306 detects the presence or absence of an error in the received data based on the error detection code added to the received data in the slot that receives the image information. The control unit 311 is notified. The control unit 311 counts the number of reception errors (notification of occurrence of reception errors from the frame processing unit 306) that occurred during a predetermined time.

  Further, the number of reception data loss is measured based on the sequence number assigned to the image information notified from the frame processing unit 306. That is, when the sequence number attached to the normally received image information notified from the frame processing unit 306 is lost, the control unit 311 receives the received data including the same divided image information being retransmitted. Are discarded by the frame processing unit 306 due to a reception error, and it is determined that the image information is missing, and the number thereof is measured. For example, the control unit 311 is notified of the normal reception of the data having the sequence number “1” given to the image information from the frame processing unit 306, and is not notified of the data having the sequence number “2”. When the normal reception of the data whose number is “3” or later is notified, it is determined that the image information is missing, and the number of times or the number of divided pieces of image information actually missing is measured.

  As described above, the control unit 311 counts the number of reception errors and the number of missing reception data occurring during a predetermined time, and after the predetermined time has elapsed, the number of reception errors and the lack of reception data. It operates so as to notify the base unit 200 of the reception state information for notifying the number of times. That is, the control unit 311 transmits the reception state information as one of the control information to the parent device 200 in the control field of the transmission slot for voice communication that performs bidirectional wireless communication.

  On the other hand, when receiving the reception state information, base unit 200 transmits the number of times the same image information is transmitted (hereinafter referred to as the number of image transmissions) based on the notified number of reception errors and the number of missing reception data. decide.

  If the number of received data loss is other than 0, the image transmission count is set to a value larger than the current value (for example, the current value is set to +1). At this time, the maximum value of the number of image transmissions may be limited. In addition, when a loss of received data occurs in the cordless handset 300 and control is performed to increase the number of image transmissions, a time lag from when the cordless handset 300 notifies the lack of received data until the number of image transmissions is increased. In some cases, the absence of received data is notified by the reception status information after the master 200 is controlled to increase the number of times of image transmission. Therefore, as a more preferable operation, when the reception state information immediately after performing the control for increasing the number of image transmissions is notified of the lack of received data, the control for preventing the number of image transmissions from increasing is not performed again. On the device 300 side, control is performed so that reception data loss that occurs within a certain time after transmission of reception status information other than zero reception data loss is not included in the number of reception data loss next time. .

  If the number of reception data loss is 0, it is determined whether to set the image transmission count to a value smaller than the current value based on the notified reception error count. Examples of threshold values used for the determination are shown in (Table 1).

  (Table 1) shows an example of the number of reception errors notified from the cordless child device 300 according to the first embodiment and the number of times that the parent device 200 transmits the same image information, which is set for the number of reception errors. ing. For example, if the number of reception errors is 6, the number of transmissions is 3. If the number of transmissions selected based on this (Table 1) is smaller than the current number of transmissions, the number of image transmissions is set to a value smaller than the current value. At this time, the number of times of change may be the number according to (Table 1), or may be the current value −1 in order to eliminate a sudden change.

  When reducing the number of times of image transmission, the number of times of image transmission is reduced in a case where a reception error occurs continuously at a fixed period by limiting the number of times of reception data loss to 0. This is because a value smaller than the number of consecutive reception errors is selected to reduce the risk of missing image information.

  Currently, a frequency band called a so-called ISM band such as the 2.4 GHz band is open as a frequency band for multipurpose use. When performing data communication in this frequency band, proprietary protocols and standards between wireless communication devices can be used, but it is necessary to satisfy the transmission characteristics for the purpose of avoiding interference with other wireless communication devices Spread spectrum and frequency hopping methods are used. When performing communication using the frequency hopping method, communication is performed while switching the communication frequency at regular intervals. When a frequency hopping method is applied to a TDMA wireless communication apparatus, transmission / reception is performed by switching the communication frequency for each slot while switching the frequency in a predetermined order on the transmission side and the reception side.

  In wireless communication by frequency hopping in the ISM band, communication control related to frequency hopping such as center frequency, bandwidth, switching period and order is not defined, and unique settings are possible. For this reason, when there are two wireless communication apparatuses that perform wireless communication using frequency hopping using the same band, interference between the wireless communication may occur continuously in a specific cycle. In addition, since the 2.4 GHz band is also used in the microwave oven, the wireless communication quality may deteriorate due to the influence of the microwave oven in a part of the 2.4 GHz band. For example, when the 2.4 GHz band is divided into 100 channels from f0 to f99, the frequencies are sequentially switched as f0, f1, f2,..., And the frequencies are switched so as to cycle through the 100 channels from f0 to f99. , When receiving the interference of the microwave oven at the frequency of f51, three consecutive errors occur during 100 receptions.

  When a reception error occurs due to the influence of an interference wave as described above, the occurrence of reception errors may occur periodically and continuously. Therefore, if the number of transmissions is set only by the number of occurrences of reception errors in the environment, the expected effect may not be obtained. For example, if the number of transmissions is determined only by the number of occurrences of reception errors in a system that allows the occurrence of data loss in one of three images, it is selected when the same threshold is used as in (Table 1). The number of transmissions is two. At this time, in an environment where reception errors always occur three times in succession, data loss occurs in all images. On the other hand, by limiting the number of transmissions so that the number of transmissions is reduced only when there is no data loss, the number of transmissions is selected from 3 to 4 times, and data loss is allowed in one image in three images. The conditions to be satisfied can be satisfied.

  Next, the transition from the voice communication state or the image communication state to the idle state will be described. When the call disconnect operation is performed with the response button 310 of the cordless handset 300 during the voice communication state and detected by the control unit 311, the voice call disconnect processing is started. The control unit 311 outputs a disconnection control signal to the frame processing unit 306 in accordance with the timing of the slot that is transmitting the voice communication, and the disconnection control signal is transmitted when the control signal for establishing the radio link is transmitted. Similarly, it is transmitted to base unit 200. When the control signal for confirming the disconnection is received from the parent device 200, the slot is in a predetermined positional relationship with the control slot among the slots that are transmitting and receiving the voice communication and receiving the image information. Stop receiving the slot, shift to receiving only the control slot, and shift to the idle state.

  On the other hand, when receiving the disconnection control signal from cordless slave unit 300, base unit 200 confirms the disconnection in the same manner as when a response signal to the wireless link establishment request is transmitted in the slot where the voice signal was transmitted. Transmission of control signals, transmission / reception of slots that were performing voice communication, and transmission of slots that are in a predetermined positional relationship with the control slot out of slots that were transmitting image information, The image transmission in the control slot is stopped and the state transitions to the idle state.

  If the master unit 200 does not receive a wireless link establishment request from the cordless slave unit 300 within a predetermined time in the image communication state, the master unit 200 stops transmission of a slot having a predetermined positional relationship with the control slot. Also, the image transmission in the control slot is stopped, and the state transitions to the idle state.

  In the description of the operation of the first embodiment, the control unit 311 counts the number of reception errors and the number of missing data received during a predetermined time, and receives the reception after the predetermined time has elapsed. Although the example in the case of operating to notify the base unit 200 of the reception status information for notifying the number of errors and the number of missing reception data has been shown, the control unit 311 immediately when detecting the lack of reception data, The master unit 200 may be notified of the lack of received data, and the master unit 200 may operate to increase the number of transmissions.

  In the description of the operation of the first embodiment, an example in which the parent device 200 operates so as to increase the number of transmissions when the lack of received data is notified from the cordless child device 300 is shown. The device 200 may add control that operates to increase the number of transmissions based on the number of reception errors notified from the cordless child device 300. For example, when the number of transmissions is two and the number of reception errors that occurred during a predetermined time is four, the number of transmissions is increased to three even if no missing data is notified. At this time, the comparison between the number of reception errors and the number of transmissions can be realized without increasing an extra storage area or the like by making it the same as the relationship of the threshold values used when reducing the number of transmissions described above. This makes it possible to increase the number of transmissions before receiving data is lost, thereby further improving communication quality.

  In the description of the operation of the first embodiment, one-way data transmission is divided into a time slot for transmitting a control signal, a time slot for transmitting a control signal, and two time slots in a predetermined position system. Although an example in which data transmission in a direction is performed has been shown, data transmission in one direction may be performed only in a time slot in which a control signal is transmitted. Further, data transmission may be performed using a time slot for transmitting a control signal, a time slot for transmitting a control signal, and a slot other than two time slots in a predetermined position system. In this case, as a more preferable operation, the master unit performs control to notify the time slot for transmitting data in one direction, the transmission frequency, etc., in the time slot for transmitting the control signal.

(Embodiment 2)
Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of a door phone that performs image transmission using the wireless communication system according to the second embodiment of the present invention. FIG. 7 is an explanatory diagram for explaining the operation of the door phone that performs image transmission using the wireless communication system according to the second embodiment of the present invention.

(Table 2)
Is an example of setting the number of transmissions for reception state information used in the wireless communication system of the present invention according to the second embodiment, and (Table 3) is transmission for reception state information used in the wireless communication system of the present invention of the second embodiment. It is a 2nd example of the setting of the frequency | count.

  Hereafter, each functional block of the door phone of Embodiment 2 comprised with the radio | wireless communications system of this invention is demonstrated using FIG. In addition, about each functional block which has an effect effect similar to each functional block of the doorphone of Embodiment 1 shown in FIG. 1 mentioned above, the same number is attached | subjected and description is abbreviate | omitted.

  In FIG. 6, reference numeral 400 denotes a master unit. In the base unit 400, a control unit 414 controls the entire base unit 400. The control unit 414 includes a dividing unit that divides the image information stored in the image information storage unit 203 into a predetermined length, a sequence number adding unit that assigns a sequence number to each of the divided image information, and a later-described unit. Determines the number of times to transmit the divided image information based on the received reception electric field strength notified from the cordless cordless handset 500, the occurrence state of the reception error, and the presence or absence of reception data (hereinafter referred to as reception state information). Operates as data transmission processing means. The control unit 414 controls each unit for transmitting image information to the cordless slave unit and controls each unit when responding to a visitor by the master unit 400.

  Reference numeral 500 denotes a cordless slave unit. In the cordless slave unit 500, 506 outputs image information, voice information, and control signals received in a time slot in which no error has occurred, and voice information and control signals to be transmitted. Is a frame processing unit that adds a synchronization signal necessary for TDMA communication and an error detection code for error detection to generate a transmission data string in accordance with a TDMA frame and time slot. The frame processing unit 506 also operates as one of a reception state detection unit and a reception error detection unit. The frame processing unit 506 performs an error detection process in accordance with a TDMA frame and a time slot from the received reception data string, and detects a reception error.

  510 is one of the reception state detection means, which is a reception field strength detection means for detecting the reception field strength of the reception signal received from the base unit 200 received by the wireless unit 307. Reference numeral 511 denotes a control unit that performs overall control of the cordless handset 500, and discards image information received redundantly based on the sequence number assigned to the received image information, and removes the redundant image information. Are received data selection means for outputting to the monitor circuit 304, and detection operation as data error detection means for detecting the presence or absence of image information, which is one of the reception status detection means. Further, the control unit 511 receives the received electric field strength detected by the received electric field strength detection unit 510, the occurrence state of the reception error detected by the reception error detection unit of the frame processing unit 506, and the received data detected by the data error detection unit. It operates to notify the base unit 400 of the reception state information for notifying the absence, and controls each unit for receiving image information, audio information, etc. sent from the base unit 400 and visits by the cordless handset 500 Control each part when responding to a person.

  Next, the operation of the above door phone will be described.

  Master device 400 and cordless slave device 500 of the second embodiment perform TDMA communication and operate as a control station, similar to master device 200 and cordless slave device 300 of the first embodiment. The cordless handset 500 operates as a dependent station. That is, base unit 400 transmits a control signal at a specific time slot in the frame, and cordless handset 500 establishes time slot synchronization with base unit 400 in the same manner as in the first embodiment. By receiving the control signal transmitted by 400, TDMA synchronization is maintained, and the arrival of a control signal notifying that the call button of the call detecting unit 103 of the front door device 100 from the parent device 400 has been pressed is awaited.

  Next, the operation in the image communication state will be described. When the control unit 414 of the base unit 400 detects that the call detection unit 103 of the front door device 100 is pressed, the call button of the call detection unit 103 of the front handset device 100 is similar to the operation of the first embodiment. A control signal notifying that the user has been pressed is transmitted, and the image of the visitor photographed by the camera unit 101 is divided and transmitted with a sequence number in the slot that transmitted the control signal.

  On the other hand, when the cordless handset 500 is notified that the call button of the call detecting unit 103 of the entrance handset 100 from the base unit 400 has been pressed, the cordless handset 500 notifies the visitor, and the order added to the received image information. Display is started by selecting image information based on the number. At this time, in the operation of receiving the image information, the received electric field strength detecting unit 510 detects the received electric field strength of the slot that received the image information and outputs it to the control unit 511. The reception error detecting unit of the frame processing unit 506 Based on the synchronization signal of the slot that received the image information and the error detection code for error detection, the presence or absence of a reception error is detected and output to the control unit 511, and the image information including the normally received sequence number is output to the control unit 514. To do.

  In the control unit 511, the reception data selection means selects image information based on the sequence number and starts display, and the data error detection means monitors the continuity of the sequence number to detect the presence or absence of image information. Then, the control unit 511 receives the average value of the received electric field strength notified from the received electric field strength detection unit 510 within a predetermined time at predetermined intervals, the number of reception error occurrences detected by the reception error detection unit, and Then, the master unit 400 is notified of the number of missing image information detected by the data error detection means as reception state information. Then, the data transmission processing unit of the control unit 414 of the base unit 400 operates to change the number of transmissions based on the notified reception state information.

  Next, the operation when transmitting the above reception status information will be described with reference to FIG. In the example of FIG. 7, as in the first embodiment, one frame is divided into eight time slots as TDMA control, and the base unit 400 operating as a control station and the cordless slave unit 500 operating as a subordinate station are wireless. When communication is performed, transmission from the base unit 400 to the cordless handset 500 is performed in the first half of the frame (1 to 4 of the time slot), and transmission from the cordless handset 500 to the base unit 400 is performed in the second half of the frame (time slot 5 to 5). An example of performing communication in 8) will be described. In addition, the time slot used for transmission / reception of image information is an example in which base unit 400 transmits only in a time slot in which a control signal is transmitted, and reception state information is transmitted in a slot corresponding to the control slot. In the example of FIG. 7, an example is shown in which a control signal is transmitted in time slot 1 and reception state information is transmitted in time slot 5.

  As shown in FIG. 7, base unit 400 corresponds to the time slot that transmitted the control signal while transmitting the image information with the sequence number in time slot 1 that transmitted the control signal in the image communication state. The radio signal is received from the cordless slave unit in the reception slot including the time slot 5 of the reception slot.

  On the other hand, the cordless handset 500 corresponds to the time slot that received the control signal at regular intervals while receiving the image information with the sequence number in the time slot 1 that received the control signal in the image communication state. The reception state information is transmitted in time slot 5 of the transmission slot. That is, when the control unit 511 of the cordless slave device 500 shifts to the image communication state, it starts a timer for determining the transmission timing of the reception state information, and when the timer expires (, S20), when the previous timer expires ( (Not shown) of the received electric field intensity notified from the received electric field intensity detecting means 510, the number of reception errors notified from the receiving error detecting means 506, and the image information detected by the data error detecting means 511. The number of missing times is transmitted as reception status information to timetable 5 of the transmission slot to base unit 400 (S21), and the timer is restarted. On the other hand, when receiving the reception state information from cordless child device 500, base unit 400 increases or decreases the number of transmissions based on the reception state information (S22). Thereafter, every time the timer expires, the reception state information is transmitted from the cordless handset 500, and every time the base unit 400 receives the reception state information, the number of transmissions is increased or decreased based on the received reception state information ( S30, S31, S32).

  Next, an example of setting the number of transmissions based on the reception state information will be described using (Table 2).

  (Table 2) shows the reception status information notified from the cordless handset 500, that is, the correspondence between the average value of the received electric field strength, the number of reception errors, and the number of times the base unit 400 set at that time transmits the same image information. An example is shown.

  Base unit 400 compares the reception status information notified from cordless handset 500, that is, the average value of the received electric field strength and the number of reception errors, with the threshold values shown in (Table 2), and determines the number of transmissions. At this time, if the number of times determined from the average value of the received electric field strength is different from the number of times determined from the number of reception error occurrences, the larger number is selected. If the number of missing image information in the reception state information is other than 0, a setting is made such that the number of transmissions is increased by selecting the number of times selected earlier and the number of times of adding 1 to the current number of transmissions. . On the other hand, when the number of missing image information in the reception state information is 0, the number of transmissions is reduced to the determined number.

  Note that when the number of transmissions is reduced by the above determination, the number of transmissions may be reduced to one less than the current value. For example, when increasing / decreasing the number of transmissions according to the threshold of (Table 2), the average value of the received electric field intensity is 40 or more and less than 50, the number of occurrences of reception errors is 0, If the number of omissions is 0, the number of transmissions determined by the average value of the received electric field strength is 2, and the number of transmissions determined by the number of reception error occurrences is 1, so the higher number of transmissions is selected, The number of transmissions is changed to 2. In addition, when the current number of transmissions is three, the average value of the received electric field strength is 40 or more and less than 50, the number of reception error occurrences is three, and the number of missing image information is one, the average value of the received electric field strength Both the number of transmissions determined by the number of transmissions and the number of transmissions determined by the number of occurrences of reception errors are two, but the number of transmissions is changed to 4 times, which is the number of times the image information is missing is not 0. The

  Next, a second example of a method for determining the number of transmissions for reception status information will be described. In the above description, the information related to the occurrence of the reception error in the reception state information is an example of the number of reception errors that occurred at a predetermined time. In the second example, the information related to the occurrence of the reception error in the reception state information is The maximum number of consecutive reception errors that occurred at a predetermined time. That is, in the second example, the control unit 511 of the cordless slave device 500 continuously generates a continuous time that occurs at a predetermined time based on whether or not a reception error is notified from the reception error detection unit of the frame processing unit 506. The maximum number of reception errors is measured and notified to base unit 400.

  Table 3 shows an example of setting the number of transmissions based on the reception state information in the second example. As shown in Table 3, the number of transmissions determined for the maximum number of continuous reception errors is a value obtained by adding 1 to the maximum number of continuous reception errors. Since the wireless communication system of the present invention operates to reduce the loss of received data by transmitting the same data multiple times, the same data is transmitted N + 1 times in an environment where consecutive reception errors occur N times. By doing so, it is possible to prevent the loss of received data. That is, in the control of the second example, with regard to the reception error that occurs randomly with the deterioration of the reception electric field strength, the continuous reception error is determined from the probability of reception error with respect to the reception electric field strength determined by the reception characteristics of the wireless communication device. Determine the probability of occurrence and determine the threshold for the number of transmissions for the received field strength so that the frequency of reception data loss due to the occurrence of continuous reception errors due to the deterioration of the received field strength is within the allowable value required for wireless communication systems. For a reception error due to a specific interference wave that causes a continuous reception error, an optimum transmission frequency is selected by determining a threshold value of the transmission frequency for the maximum number of continuous reception errors. The method of determining the number of transmissions by combining the number of transmissions determined by the received electric field strength, the number of transmissions determined by the maximum number of consecutive reception errors, the number of missing image information, and the current number of transmissions is as described above. The description is omitted.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments. In the second embodiment, the average value of the received electric field strength, the number of reception errors, and the image Although the number of transmissions is determined by combining the number of missing information, two combinations such as the number of reception errors and the number of missing image information may be used as in the first embodiment, or may be determined independently. . For example, when determining the number of transmissions based only on the number of missing image information, increase the number of transmissions every time notification of missing image information, and reduce the number of transmissions if there is no missing image information for a certain period of time. May work. Preferably, the number of pieces of information to be used as the reception state information should be determined by a trade-off between the reliability and response speed of data communication required for the system and the cost for realizing it. For example, when the present invention is applied to a system that requires reliability of data communication such as a security camera, a reliable method of determining the number of transmissions based on a plurality of reception state information is used, such as a door phone. If the reliability of data communication is low, the number of times of transmission of one or two pieces of reception state information is determined to simplify the circuit and control of the apparatus.

  In the above embodiment, the information notified as the reception state is an example of the average value of the received electric field strength, the number of reception errors, and the number of missing image information. It only needs to be able to determine the superiority or inferiority of the state, and is an index of superiority or inferiority in reception quality such as bit error rate, received signal S / N (ratio of desired wave to noise), eye opening of demodulated signal, etc. If available.

  In the first and second embodiments, the example in which the cordless slave unit operates by one unit has been shown. However, like a door phone configured by one master unit and a plurality of cordless slave units, the reception side This is also applicable to a plurality of wireless communication systems, and a plurality of cordless slave units may receive one-way data communication information transmitted from the master unit. That is, in the wireless communication system and the communication method of the present invention, data transmission from the first wireless communication device to the second wireless communication device is performed by one-way wireless communication that does not require wireless link negotiation. The number of second wireless communication devices on the receiving side is not limited.

  As a preferable operation example in the case of transmitting data from the first wireless communication device to a plurality of second wireless communication devices, each second wireless communication device detects a reception state, and each of them receives the first wireless communication device. The first wireless communication device determines the number of transmissions according to the second wireless communication device with the worst reception state based on the reception state notified from each second wireless communication device. By operating so as to set, good communication is possible even when there are a plurality of second wireless communication apparatuses.

  The present invention can reduce deterioration in communication quality when the first wireless communication device and one or more second wireless communication devices perform one-way data transmission, so that one or more devices from the first wireless communication device can be reduced. This is suitable for a wireless communication system that transmits data to the second wireless communication apparatus.

1 is a block diagram of a door phone that performs image transmission using the wireless communication system according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram showing a TDMA frame and slot configuration in the wireless communication system according to the first embodiment of the present invention. Explanatory drawing which shows the example of the format of the data sequence communicated with the radio | wireless communications system of Embodiment 1 of this invention. Explanatory drawing explaining operation | movement which divides | segments and transmits image information in the radio | wireless communications system of Embodiment 1 of this invention. Explanatory drawing explaining operation | movement of the door phone which performs image transmission using the radio | wireless communications system of Embodiment 1 of this invention. Block diagram of a doorphone that performs image transmission using the wireless communication system according to the second embodiment of the present invention Explanatory drawing explaining operation | movement of the door phone which performs image transmission using the radio | wireless communications system of Embodiment 2 of this invention. FIG. 1 is an external view of an entrance terminal of a wireless communication system according to an embodiment of the present invention 1 is an external view of a door phone master unit of a wireless communication system according to an embodiment of the present invention. External view of cordless telephone cordless handset of wireless communication system according to an embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Entrance child machine 101 Camera part 102 Calling part 103 Call detection part 104 Demultiplexing circuit 200 Master unit 220 Demultiplexing circuit 201 Monitor circuit 202 Monitor 203 Image information storage part 204 Call detection part 205 Notification part 206 Voice circuit 207 Calling part 208 Response Button 209 Frame processing unit 210 Radio unit 213 Antenna 214 Control unit 300 Cordless handset 301 Notification unit 302 Voice circuit 303 Calling unit 304 Monitor circuit 305 Monitor 306 Frame processing unit 307 Radio unit 308 Antenna 310 Response button 311 Control unit

Claims (25)

  1. A wireless communication system for performing data communication between a first wireless communication device and a second wireless communication device,
    The second wireless communication device comprises: received data selection means for selecting only new received data from data sequentially received from the first wireless communication device by one-way communication; and the first wireless communication device A reception state detection unit that detects a reception state in data communication with the wireless communication device, and operates to notify the reception state detected by the reception state detection unit to the first wireless communication device;
    The first wireless communication device includes data transmission processing means for determining the number of times to transmit data based on the reception state notified from the second wireless communication device,
    The data transmission processing means operates to increase the number of times of transmitting data when notified of the deterioration of the reception state, and to decrease the number of transmissions when notified of recovery of the deterioration of the reception state. Wireless communication system.
  2. 2. The wireless communication system according to claim 1, wherein the reception state detecting means detects a received electric field strength of data transmitted from the first wireless communication device.
  3. 2. The wireless communication system according to claim 1, wherein the reception state detection means detects a state of occurrence of a reception error of data transmitted from the first wireless communication device.
  4. 2. The wireless communication system according to claim 1, wherein the reception state detecting means detects a discontinuity in continuity of received data of data transmitted from the first wireless communication device.
  5. The reception state detection means is a reception electric field strength of data transmitted from the first wireless communication device, a generation state of a reception error of data transmitted from the first wireless communication device, or from the first wireless communication device. 2. The wireless communication system according to claim 1, wherein any two or more interruptions in continuity of received data of transmitted data are detected.
  6. The reception state detection means of the second wireless communication device comprises data error detection means for detecting the presence or absence of reception data, and reception quality detection means for detecting the wireless quality of the received signal,
    The second wireless communication device operates to notify the first wireless communication device of the presence or absence of reception data detected by the data error detection means and the reception quality detection means and reception quality,
    The first wireless communication apparatus includes data transmission processing means for determining the number of times of data transmission based on the presence / absence of missing reception data and reception quality notified from the second wireless communication apparatus, and the data transmission The processing means increases the number of times of transmitting data when notified of reception data loss or reception quality deterioration, and transmits based on the notified reception quality when notified of no reception data loss. The wireless communication system according to claim 1, wherein the wireless communication system operates so as to reduce the number of times to perform.
  7. 7. The wireless communication system according to claim 6, wherein the reception quality detecting means detects a received electric field strength of data transmitted from the first wireless communication device.
  8. 7. The wireless communication system according to claim 6, wherein the reception quality detection means detects an occurrence state of a reception error of data transmitted from the first wireless communication device.
  9. The reception quality detection means detects a reception electric field strength of data transmitted from the first wireless communication device and a state of occurrence of a reception error of data transmitted from the first wireless communication device. The wireless communication system according to claim 6.
  10. The first wireless communication device includes a dividing unit that divides transmission data into a predetermined length;
    A sequence number giving means for giving a sequence number to each transmission data divided by the dividing means, the received data selecting means selecting new received data based on the sequence number, and the reception status detecting means or 10. The wireless communication system according to claim 1, wherein the data error detection means detects the presence or absence of reception data based on the sequence number.
  11. The wireless communication system including the first wireless communication device and the second wireless communication device performs one-way data communication from the first wireless communication device to the second wireless communication device and simultaneously performs the first wireless communication. A wireless communication system that performs communication using a multiplexing method that performs bidirectional wireless communication between a device and a second wireless communication device, wherein the reception state detected by the reception state detection means is the first wireless communication When notifying the device, a transmission signal from the second wireless communication device to the first wireless communication device in bidirectional wireless communication between the first wireless communication device and the second wireless communication device is used. 11. The wireless communication system according to claim 1, wherein:
  12. In bi-directional wireless communication between the first wireless communication device and the second wireless communication device, a data string transmitted in one section that is self-division multiplexed is a control data field for transmitting a control signal. 12. The wireless communication system according to claim 11, further comprising an information data field for transmitting an information signal, wherein the reception state detected by the reception state detection means is transmitted in the control data field.
  13. A wireless communication device that performs communication with another wireless communication device that changes the number of transmissions based on the reception state of the communication partner while transmitting the transmission data by dividing it into a predetermined length,
    Received data selection means for selecting only new received data from the data sent from the other wireless communication device and sequentially received;
    A reception state detection means for detecting a reception state of data sent from the other wireless communication device,
    A wireless communication system, wherein a reception state detected by the reception state detection means is notified to another wireless communication device that is a transmission source of the data.
  14. The reception state detection means is a reception electric field strength of data transmitted from another wireless communication device, a reception error occurrence state of data transmitted from another wireless communication device, or transmitted from another wireless communication device. 14. The wireless communication system according to claim 13, wherein any two or more discontinuities in received data continuity are detected.
  15. The reception data selection means selects new reception data based on a sequence number assigned to data transmitted from another wireless communication device, and the reception state detection means selects reception data based on the sequence number. The wireless communication system according to claim 13, wherein presence / absence of a lack is detected.
  16. Communicating with other wireless communication devices that detect the reception state of data while selecting only new reception data from sequentially received data, and notify the transmission source, to the other wireless communication devices A wireless communication device that transmits data by one-way communication,
    A dividing means for dividing the transmission data into a predetermined length;
    Data transmission processing means for determining the number of times to transmit data based on the reception state notified from the other wireless communication device,
    The data transmission processing means operates to increase the number of times of transmitting data when notified of the deterioration of the reception state, and to decrease the number of transmissions when notified of recovery of the deterioration of the reception state. Wireless communication system.
  17. 17. The wireless communication system according to claim 16, further comprising sequence number assigning means for assigning a sequence number to each transmission data divided by the dividing means.
  18. Data transmission processing means for determining the number of times of data transmission based on the presence or absence of reception data and reception quality notified from other wireless communication devices,
    The data transmission processing means increases the number of times of data transmission when notified of reception data loss or reception quality deterioration, and based on the notified reception quality when notified of no reception data loss. The wireless communication system according to claim 16, wherein the number of transmissions is reduced.
  19. A communication method for performing data communication between a first wireless communication device and a second wireless communication device, wherein the second wireless communication device is transmitted from the first wireless communication device by one-way communication. Selecting only new received data from the sequentially received data, performing reception processing, notifying the first wireless communication device of the reception state in data communication with the first wireless communication device, The first wireless communication apparatus determines the number of times to transmit data based on the reception state notified from the second wireless communication apparatus.
  20. The reception state of the one-way data communication notified to the first wireless communication device is the received electric field strength of the data transmitted from the first wireless communication device or the data transmitted from the first wireless communication device. 20. The communication system according to claim 19, wherein the communication system is either in a state of occurrence of a reception error or in a state of occurrence of a discontinuity in continuity of received data transmitted from the first wireless communication device.
  21. The second wireless communication apparatus notifies the first wireless communication apparatus of the presence or absence of reception data and the reception quality at the time of reception as a reception state, and the first wireless communication apparatus transmits the second wireless communication apparatus. The number of times that data is transmitted may be increased when there is a lack of received data or reception quality is notified based on the presence or absence of received data and reception quality notified from the communication device, and there is no lack of received data. 20. The communication method according to claim 19, wherein when notified, the number of times of transmitting data is determined so as to reduce the number of times of transmission based on the notified reception quality.
  22. The reception quality notified to the first wireless communication device includes the reception field strength of the data transmitted from the first wireless communication device and the occurrence state of the reception error of the data transmitted from the first wireless communication device. The communication method according to claim 21, wherein:
  23.   The first wireless communication apparatus divides transmission data into predetermined lengths, assigns a sequence number to each of the divided transmission data, and transmits the data. The first wireless communication apparatus 23. The method according to claim 19, wherein new received data is selected based on the sequence number, and the second wireless communication apparatus detects presence / absence of missing received data based on the sequence number. Communication method described
  24. Using a multiplexing system that performs one-way data communication from the first wireless communication device to the second wireless communication device and simultaneously performs bidirectional wireless communication between the first wireless communication device and the second wireless communication device. A communication method of a wireless communication system for performing communication, wherein when the first wireless communication device is notified of a reception state in data communication with the first wireless communication device, the first wireless communication device and the second wireless communication device 24. The communication method according to claim 19, wherein a transmission signal from the second wireless communication device to the first wireless communication device in bidirectional wireless communication between the wireless communication devices is used. .
  25. In bi-directional wireless communication between the first wireless communication device and the second wireless communication device, a data string transmitted in one section that is self-division multiplexed is a control data field for transmitting a control signal. 25. The communication system according to claim 24, further comprising an information data field for transmitting an information signal, wherein a reception state in data communication with the first wireless communication device is transmitted in the control data field.
JP2005191432A 2005-06-30 2005-06-30 Radio communication system and its communication method Pending JP2007013544A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005191432A JP2007013544A (en) 2005-06-30 2005-06-30 Radio communication system and its communication method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005191432A JP2007013544A (en) 2005-06-30 2005-06-30 Radio communication system and its communication method

Publications (1)

Publication Number Publication Date
JP2007013544A true JP2007013544A (en) 2007-01-18

Family

ID=37751443

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005191432A Pending JP2007013544A (en) 2005-06-30 2005-06-30 Radio communication system and its communication method

Country Status (1)

Country Link
JP (1) JP2007013544A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008244988A (en) * 2007-03-28 2008-10-09 Kyocera Corp Information distribution apparatus and system, and control method of multicast distribution
JP2011060192A (en) * 2009-09-14 2011-03-24 Sumitomo Electric Ind Ltd Road-vehicle communication system and on-board unit
WO2013077472A1 (en) * 2011-11-24 2013-05-30 Panasonic Corporation Wireless communication apparatus, wireless communication system and wireless communication method
WO2014016960A1 (en) * 2012-07-27 2014-01-30 三菱電機株式会社 Network system
JP2014123859A (en) * 2012-12-21 2014-07-03 Fujitsu Ltd Communication base station, collection control device and communication method
JP2014204398A (en) * 2013-04-09 2014-10-27 パナソニック株式会社 Radio communication method
KR20150090145A (en) * 2012-11-26 2015-08-05 퀄컴 인코포레이티드 Opportunistic decoding of transmissions on a forward link in a machine-to-machine wireless wide area network

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008244988A (en) * 2007-03-28 2008-10-09 Kyocera Corp Information distribution apparatus and system, and control method of multicast distribution
JP2011060192A (en) * 2009-09-14 2011-03-24 Sumitomo Electric Ind Ltd Road-vehicle communication system and on-board unit
WO2013077472A1 (en) * 2011-11-24 2013-05-30 Panasonic Corporation Wireless communication apparatus, wireless communication system and wireless communication method
JP2013110708A (en) * 2011-11-24 2013-06-06 Panasonic Corp Wireless communication system and wireless communication apparatus
US9148905B2 (en) 2011-11-24 2015-09-29 Panasonic Intellectual Property Management Co., Ltd. Wireless communication apparatus , wireless communication system and wireless communication method
WO2014016960A1 (en) * 2012-07-27 2014-01-30 三菱電機株式会社 Network system
KR102110864B1 (en) * 2012-11-26 2020-06-08 퀄컴 인코포레이티드 Opportunistic decoding of transmissions on a forward link in a machine-to-machine wireless wide area network
KR20150090145A (en) * 2012-11-26 2015-08-05 퀄컴 인코포레이티드 Opportunistic decoding of transmissions on a forward link in a machine-to-machine wireless wide area network
US9973879B2 (en) 2012-11-26 2018-05-15 Qualcomm Incorporated Opportunistic decoding of transmissions on a forward link in a machine-to-machine wireless wide area network
JP2015537482A (en) * 2012-11-26 2015-12-24 クゥアルコム・インコーポレイテッドQualcomm Incorporated Opportunistic decoding of transmissions on the forward link in machine-to-machine wireless wide area networks
JP2014123859A (en) * 2012-12-21 2014-07-03 Fujitsu Ltd Communication base station, collection control device and communication method
US9413453B2 (en) 2013-04-09 2016-08-09 Panasonic Intellectual Property Management Co., Ltd. Wireless communication method and wireless communication system
JP2014204398A (en) * 2013-04-09 2014-10-27 パナソニック株式会社 Radio communication method

Similar Documents

Publication Publication Date Title
US20170127191A1 (en) Hearing aid using wireless test modes as diagnostic tool
JP6017731B2 (en) Method and system for using a Wi-Fi display transport mechanism for performing voice and data communications
US9712266B2 (en) Synchronization of multi-channel audio communicated over bluetooth low energy
US9185721B2 (en) Random access preamble transmission design with multiple available random access channel resources
KR100972405B1 (en) Method and apparatus for improving MIMO operation in a wireless communications system
US7389318B2 (en) Data processor capable of preventing data overflows and underflows
US8620154B2 (en) Methods and apparatus for fast and energy-efficient light recovery in a visible light communication (VLC) system
US6011784A (en) Communication system and method using asynchronous and isochronous spectrum for voice and data
KR100792586B1 (en) Method and apparatus for handling control PDUS during re-establishing receiving sides in a wireless communications system
US9350770B2 (en) Redundant transmission channels for real-time applications on mobile devices
US9553913B2 (en) Seamless video pipeline transition between WiFi and cellular connections for real-time applications on mobile devices
US6839079B2 (en) Video-telephony system
KR100953151B1 (en) Method of enhancing continuous packet connectivity in a wireless communications system and related apparatus
US8107999B2 (en) Communication device and method of communicating transmissions
US6774928B2 (en) Mobile for video-conferencing
US8204435B2 (en) Wireless headset supporting enhanced call functions
US7999840B2 (en) Method for performing video communication service and mobile communication terminal therefor
DE602004012457T2 (en) Wireless audio transmission system and method with dynamic time slot assignment
US8498678B2 (en) System and method for reducing power consumption in a wireless device
JP4575915B2 (en) Communication of conversation data signals between terminal devices via wireless links
JP4637109B2 (en) Group call management with incoming / outgoing synchronization
US8291273B2 (en) Communication device, non-transitory computer-readable medium storing a communication program
JP5087479B2 (en) Method and apparatus for improving HARQ function in a wireless communication system
JP3021101B2 (en) Frequency division multiplexing (FDM) -time division duplex (TDD) communication device operating method
EP0877513A1 (en) Dynamic configuration of radio link protocol in a telecommunications system