JP2007306498A - Communication apparatus, data communication method, and data communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus, a data communication method, and a data communication system capable of improving the communication quality in the case of communicating data to a plurality of destinations. <P>SOLUTION: The communication apparatus 10 in order to solve the task above for making data communication with a plurality of other communication apparatuses connected via a network includes: a reception means 32 for receiving the data addressed to the destinations from the other communication apparatuses; a response signal generating means 34 for generating a response signal denoting failed reception when the communication apparatus 10 is failed to receive the data addressed to the destinations; and a transmission means 31 for transmitting the response signal to senders of the destinations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication device, a data communication method, and a data communication system, and more particularly to a communication device, a data communication method, and a data communication system that transmit / receive data of a plurality of destinations.

  For example, in a network capable of data communication, toward a unicast that designates a single communication device and transmits data, a multicast that designates a plurality of communication devices and transmits the same data, and an unspecified number of communication devices Broadcast that transmits the same data is used for the purpose of data communication.

  In unicast, a communication device that receives data (hereinafter referred to as a receiving station) returns a reception confirmation (acknowledgement: ACK) to a communication device that transmits data (hereinafter referred to as a transmitting station). The ACK is a response from the receiving station to the transmitting station that data has been successfully received.

  FIG. 1 is an explanatory diagram showing an example of ACK in unicast. FIG. 1 shows a case where the own device is a transmitting station. Normally, in unicast, the receiving station returns a reception confirmation (acknowledgement: ACK) to the transmitting station. In the unicast in FIG. 1, after transmitting a unicast frame as a transmission frame to a reception station, an ACK frame is received as a reception frame from the reception station.

  On the other hand, in multicast and broadcast, when a receiving station returns an ACK to a transmitting station, ACKs are simultaneously returned from a plurality of receiving stations to the transmitting station.

  FIG. 2 is an explanatory diagram showing an example of ACK in multicast. FIG. 2 shows a case where the own device is a transmitting station. As shown in FIG. 2, in multicast, if a transmitting station transmits a multicast frame as a transmission frame to a receiving station and then receives an ACK frame as a reception frame from the receiving station, interference occurs.

  Multicast and broadcast capable of transmitting the same data to a plurality of destinations have very high compatibility with wireless communication that performs data communication using radio waves. In wireless communication, wireless media may not be in an appropriate state for communication due to noise of other devices, and in the case of unicast, an ACK frame is returned to ensure communication quality.

  On the other hand, in the case of multicast and broadcast, if ACK is returned, ACK is returned from a plurality of receiving stations to the transmitting station at the same time. For this reason, in the case of multicast and broadcast, the transmitting station cannot confirm whether or not the receiving station has received correctly, and there is a problem in communication quality.

For example, Patent Document 1 describes the content of transmitting the same data multiple times using a communication idle time as one of solutions to the above problem by not returning an ACK frame in multicast.
Patent Document: Japanese Patent Laid-Open No. 9-266493

  However, the content described in Patent Document 1 is to supplement missing data in subsequent data when the same data is transmitted a plurality of times and the first data is missing. The content described in Patent Document 1 increases the probability that the receiving station can receive correctly by transmitting the same data multiple times, but can confirm whether the receiving station has received correctly. is not.

  In particular, wireless communication is often not in an appropriate state for communication due to noise from other devices as compared to wired communication, and communication quality is ensured if the transmitting station cannot confirm whether it has received correctly. There was a problem that I could not.

  SUMMARY An advantage of some aspects of the invention is that it provides a communication device, a data communication method, and a data communication system capable of improving communication quality when data communication is performed on data of a plurality of destinations. .

  In order to solve the above-described problems, the present invention provides a communication device that performs data communication with a plurality of other communication devices connected via a network, and receives data of a plurality of destinations from the other communication devices. Receiving means for receiving, response signal generating means for generating a response signal indicating failure in reception when reception of the data at the plurality of destinations has failed, and transmission means for transmitting the response signal to a transmission source for the data at the plurality of destinations. It is provided with.

  In order to solve the above-described problem, the present invention provides a communication device that performs data communication with a plurality of other communication devices connected via a network. Transmitting means for transmitting to the communication device, receiving means for receiving a response signal indicating failure in receiving the data at the plurality of destinations from at least one of the plurality of other communication devices, and reception failure of the data at the plurality of destinations received. And a retransmission determination unit that instructs the transmission unit to retransmit the data of the plurality of destinations based on the response signal.

  In order to solve the above-described problem, the present invention provides a data communication method for a communication device that performs data communication with a plurality of other communication devices connected via a network, and the other communication device. A reception step of receiving data of a plurality of destinations, a response signal generation step of generating a response signal of reception failure when reception of the data of the plurality of destinations fails, and the response signal to a transmission source of the data of the plurality of destinations And a transmission step for transmitting.

  Further, the present invention is a data communication method for a communication apparatus for performing data communication with a plurality of other communication apparatuses connected via a network, in order to solve the above-described problem. A transmission step of transmitting to the plurality of other communication devices; a reception step of receiving a response signal indicating failure in reception of the data of the plurality of destinations from at least one of the plurality of other communication devices; A retransmission determination step for instructing retransmission of the data of the plurality of destinations based on a response signal indicating failure in data reception.

  In order to solve the above problems, the present invention includes a plurality of communication devices connected via a network, and performs data communication between one communication device and a plurality of other communication devices. The plurality of other communication devices receive a first reception means for receiving data of a plurality of destinations from the one communication device, and a reception failure response signal when reception of the data of the plurality of destinations fails. Response signal generating means for generating and first transmission means for transmitting the response signal to the one communication apparatus, wherein the one communication apparatus transmits the data of the plurality of destinations to the plurality of other communication apparatuses. Second transmission means for receiving, a second reception means for receiving a response signal indicating failure in reception of the data at the plurality of destinations from at least one of the plurality of other communication devices, and reception failure of the data at the plurality of destinations received. Response signal Based, wherein the retransmission data of the plurality of destinations and a retransmission decision unit for instructing said second transmission means.

  In the present invention, the communication device that has failed to receive data returns a response signal indicating that the data has been received to the communication device that has transmitted the data. Therefore, communication quality can be improved.

  In addition, what applied the component, expression, or arbitrary combination of the component of this invention to a method, an apparatus, a system, a computer program, a recording medium, a data structure, etc. is also effective as an aspect of this invention.

  According to the present invention, it is possible to provide a communication apparatus, a data communication method, and a data communication system that can improve communication quality when data communication is performed on data of a plurality of destinations.

  Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings. In addition, although a wireless communication is demonstrated to an example in a present Example, the application to wired communication and in-device communication is also possible.

  FIG. 3 is a block diagram of an embodiment of a data communication system including a plurality of communication devices. The data communication system shown in FIG. 3 is configured to include one transmitting station 1 and four receiving stations 2A to 2D. Here, an example in which multicasting is performed from the transmitting station 1 to the receiving stations 2A to 2D will be described. In addition, when any of the receiving stations 2A to 2D may be used, it is simply referred to as a receiving station 2.

  Note that the transmitting station 1 and the receiving stations 2A to 2D are realized by a communication device 10 having a hardware configuration as shown in FIG. FIG. 4 is a hardware configuration diagram of an example of the communication apparatus. The communication device 10 includes a control unit 11, an I / F unit 12, a protocol processing unit 13, a modem unit 14, and an RF unit 15. The I / F unit 12 is an interface with a device 10 such as a multifunction peripheral (MFP) or a PC connected to the communication device 10.

  The protocol processing unit 13 converts the data received from the device 20 according to a predetermined protocol and transmits the converted data to the modulation / demodulation unit 14, or returns the data according to the predetermined protocol received from the modulation / demodulation unit 14 and transmits the data to the device 20. To do. The modem unit 14 modulates data (modulated signal) according to a predetermined protocol received from the protocol processing unit 13, and transmits the modulated wave to the RF unit 15. Further, the modem unit 14 demodulates the modulated wave received from the RF unit 15 and transmits data according to a predetermined protocol to the protocol processing unit 13.

  The RF unit 15 converts the modulation wave received from the modulation / demodulation unit 14 into a radio frequency (RF) and outputs it from the antenna, or converts the modulation wave of the radio frequency input from the antenna into the original frequency and converts the modulation wave to the modulation / demodulation unit 14. Send to. The control unit 11 controls the I / F unit 12, the protocol processing unit 13, the modem unit 14, and the RF unit 15.

  With the hardware configuration shown in FIG. 4, the communication apparatus 10 realizes a processing block as shown in FIG. 5. FIG. 5 is a processing block diagram of an example of the communication apparatus. The communication device 10 includes a transmission unit 31, a reception unit 32, an interface unit 33, a response signal generation unit 34, and a retransmission determination unit 35.

  The transmission unit 31 transmits a frame to the transmission station 1. The receiving unit 32 receives a frame from the transmitting station 1. The interface unit 33 is an interface with the device 20. When the response signal generation unit 34 fails to receive the multicast frame, the response signal generation unit 34 generates a response signal of reception failure (not acknowledge: NACK). When receiving a NACK response signal from the receiving station 2, the retransmission determination unit 35 instructs the transmission unit 31 to retransmit the multicast frame. NACK is a response from the receiving station 2 to the transmitting station 1 that reception of a multicast frame has failed.

  Hereinafter, the present invention will be described based on the message sequence chart of FIG. FIG. 6 is an example message sequence chart showing the processing procedure of the data communication system according to the present invention.

  Each communication device 10 (transmitting station 1, receiving station 2A to 2D) constituting the data communication system does not respond to a multicast frame in order to cope with communication in which compatibility with a normal communication device and signal quality do not matter. It is desirable that data communication is possible. Assuming that data communication not responding to a multicast frame is normally performed, in the data communication system, when the multicast data communication according to the present invention is started, it is confirmed that the receiving stations 2A to 2D can communicate with the transmitting station 1. is required. For example, the transmitting station 1 confirms that the receiving stations 2A to 2D are in a communicable position.

  In steps S1 to S4, the transmitting station 1 notifies the receiving stations 2A to 2D of the start of multicast data communication according to the present invention using a unicast frame or a multicast frame using a start notification frame. The receiving stations 2A to 2D that have received the start notification frame proceed to steps S5 to S8, and respond to the transmitting station 1 with a start response frame that multicast data communication according to the present invention can be started.

  The transmitting station 1 considers that the receiving station 2 that has not received the start response frame at this stage cannot participate in the multicast data communication according to the present invention. If the start response frame cannot be received from the receiving station 2 that needs to participate in the multicast data communication according to the present invention, the start notification frame is transmitted again from the transmitting station 1 to the receiving stations 2A to 2D. As an error occurs, multicast data communication according to the present invention is stopped.

  Proceeding to steps S9 to S12, the transmitting station 1 transmits a multicast frame to the receiving stations 2A to 2D. In steps S9 to S12, it is assumed that the receiving stations 2A to 2D have successfully received the multicast frame. When the receiving stations 2A to 2D have successfully received the multicast frame, no special processing is performed in the data communication system according to the present invention.

  If the transmitting station 1 does not receive a NACK response signal (NACK frame) for a predetermined time after transmitting a multicast frame in steps S9 to S12, the process proceeds to steps S13 to S16. In steps S13 to S16, the transmitting station 1 transmits a multicast frame to the receiving stations 2A to 2D. In steps S13 to S16, it is assumed that the receiving stations 2A to 2D have successfully received the multicast frame. As in steps S9 to S12, since the receiving stations 2A to 2D have successfully received the multicast frame, no special processing is performed in the data communication system according to the present invention.

  If the transmitting station 1 does not receive a NACK response signal (NACK frame) for a predetermined time after transmitting a multicast frame in steps S13 to S16, the process proceeds to steps S17 to S20.

  In steps S17 to S20, the transmitting station 1 transmits a multicast frame to the receiving stations 2A to 2D. In steps S17 to S20, it is assumed that the receiving station 2D has failed to receive the multicast frame for some reason. The receiving station 2D determines that the reception of the multicast frame has failed when the multicast frame is not received for a predetermined time, or when the received multicast frame is broken and cannot be restored.

  In step S21, the receiving station 2D generates a NACK frame and transmits the NACK frame to the transmitting station 1, thereby responding to the transmitting station 1 that reception of the multicast frame has failed. When receiving the NACK frame from the receiving station 2D, the transmitting station 1 proceeds to steps S22 to S25 and retransmits the multicast frame to the receiving stations 2A to 2D.

  Receiving stations 2A to 2C that have successfully received the multicast frame may ignore the retransmitted multicast frame, or may adopt the retransmitted multicast frame in steps S22 to S24.

  If the transmitting station 1 does not receive a NACK response signal (NACK frame) for a predetermined time after retransmitting the multicast frame in steps S22 to S25, the process proceeds to steps S26 to S29. In steps S22 to S25, it is assumed that the receiving stations 2A to 2D have successfully received the multicast frame.

  In steps S26 to S29, the transmitting station 1 transmits a multicast frame to the receiving stations 2A to 2D. In steps S26 to S29, it is assumed that the receiving stations 2C and 2D have failed to receive the multicast frame for some reason.

  Proceeding to steps S30 and S31, the receiving stations 2C and 2D generate a NACK frame and transmit the NACK frame to the transmitting station 1, thereby attempting to respond to the transmitting station 1 that reception of the multicast frame has failed. There is a possibility that the receiving stations 2C and 2D transmit the NACK frame at the same time. In this case, there is a high possibility that the transmitting station 1 will not be able to restore the NACK frame due to interference.

  The transmitting station 1 can expect that the receiving station 2 has failed to receive the multicast frame when the wireless medium becomes busy at the timing when the NACK frame is received. When the wireless medium becomes busy at the timing when the NACK frame is received, the transmitting station 1 determines that the NACK frame has been received. Then, the transmitting station 1 proceeds to steps S32 to S35, and retransmits the multicast frame to the receiving stations 2A to 2D.

  The wireless media is busy is a state where some radio wave is generated in the frequency band used by the wireless media. In wireless USB as an example of wireless communication, when detecting by MAC, it can be determined whether or not the wireless medium is busy depending on whether or not the CCA_STATUS signal is active. Wireless USB is a wireless interface based on ultra-wideband wireless (UWB) technology that is an extension of USB. Details of the CCA_STATUS signal are described in the wireless USB PHY specification.

  If the transmitting station 1 does not receive the NACK frame for a predetermined time after retransmitting the multicast frame in steps S32 to S35, it determines that the receiving stations 2A to 2D have successfully received the multicast frame.

  When all transmission of the multicast frame assumed by the transmission station 1 is completed or when data communication is stopped, it is desirable to perform an end process. For example, the receiving station 2A to 2D can return to normal data communication not responding to the multicast frame by the end process of transmitting the end notification frame from the transmitting station 1 to the receiving stations 2A to 2D.

  When the end process is not performed, the end process can be performed by a timeout process or a frame number out process by setting the end time or the number of frames in the start notification frame. By setting the frame number in the start notification frame, the end process can be performed when the frame number is reached.

  Further, the WiMedia standard allows vendor-specific command frames, and the start notification frame and the end notification frame can be omitted by performing multicast data communication according to the present invention using the unique frame.

  The present invention is not limited to the specifically disclosed embodiments, and various modifications and changes can be made without departing from the scope of the claims.

It is explanatory drawing which showed the example of ACK in unicast. It is explanatory drawing which showed the example of ACK in a multicast. It is a block diagram of one Example of the data communication system containing a some communication apparatus. It is a hardware block diagram of an example of a communication apparatus. It is a process block diagram of an example of a communication apparatus. It is a message sequence chart of an example showing the processing procedure of the data communication system by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmitting station 2, 2A-2D Receiving station 10 Communication apparatus 11 Control part 12 I / F part 13 Protocol processing part 14 Modulation / demodulation part 15 RF part 20 Equipment 31 Transmission part 32 Reception part 33 Interface part 34 Response signal generation part 35 Retransmission judgment Part

Claims (20)

A communication device that performs data communication with a plurality of other communication devices connected via a network,
Receiving means for receiving data of a plurality of destinations from the other communication device;
A response signal generating means for generating a reception failure response signal when reception of the data of the plurality of destinations fails;
A communication apparatus comprising: a transmission unit configured to transmit the response signal to a transmission source of the plurality of destination data.   The response signal generation means receives the data of the plurality of destinations when the data of the plurality of destinations scheduled to be received cannot be received after a predetermined time based on the information indicating the data of the plurality of destinations scheduled to be received. The communication device according to claim 1, wherein the communication device is determined to have failed.   3. The information indicating the data of the plurality of destinations scheduled to be received is received from the other communication device in advance or embedded at the beginning and end of the data of the plurality of destinations. Communication equipment. A communication device that performs data communication with a plurality of other communication devices connected via a network,
Transmitting means for transmitting data of a plurality of destinations to the plurality of other communication devices;
Receiving means for receiving a response signal indicating failure in receiving the data of the plurality of destinations from at least one of the plurality of other communication devices;
A communication apparatus, comprising: a retransmission determination unit that instructs the transmission unit to retransmit the multi-destination data based on a received failure response signal of the multi-destination data.   5. The communication according to claim 4, wherein when the receiving unit receives a response signal that cannot be restored, the retransmission determining unit determines that a response signal indicating failure in receiving the data of the plurality of destinations has been received. apparatus.   The retransmission determination unit determines that a response signal indicating failure in receiving the data of the plurality of destinations has been received when interference occurs in the frequency band used for the data communication at the timing of receiving the response signal. The communication apparatus according to claim 4.   The communication apparatus according to claim 1, wherein the communication apparatus performs wireless communication. A data communication method of a communication device for performing data communication with a plurality of other communication devices connected via a network,
A receiving step of receiving data of a plurality of destinations from the other communication device;
A response signal generating step of generating a response signal indicating failure in reception when reception of the data of the plurality of destinations fails;
A data communication method comprising: a transmission step of transmitting the response signal to a transmission source of the plurality of destination data.   The response signal generation step receives the data of the plurality of destinations when the data of the plurality of destinations scheduled to be received cannot be received even after a predetermined time based on the information indicating the data of the plurality of destinations scheduled to be received. 9. The data communication method according to claim 8, wherein the data communication method is determined to have failed.   10. The information indicating the data of the plurality of destinations scheduled to be received is received from the other communication device in advance or embedded at the beginning and end of the data of the plurality of destinations. Data communication method. A data communication method of a communication device for performing data communication with a plurality of other communication devices connected via a network,
Transmitting a plurality of destination data to the plurality of other communication devices;
A reception step of receiving a response signal indicating failure in receiving the data of the plurality of destinations from at least one of the plurality of other communication devices;
A data communication method comprising: a retransmission determination step for instructing retransmission of the data of the plurality of destinations based on the received failure response signal of the data of the plurality of destinations.   12. The data according to claim 11, wherein, in the retransmission determination step, when the reception unit receives a response signal that cannot be restored, it is determined that a response signal indicating failure in reception of the data of the plurality of destinations has been received. Communication method.   In the retransmission determination step, it is determined that a response signal indicating failure in reception of the data of the plurality of destinations is received when interference occurs in the frequency band used for the data communication at the timing of receiving the response signal. The data communication method according to claim 11.   The data communication method according to claim 8, wherein the communication device performs wireless communication. A data communication system including a plurality of communication devices connected via a network and performing data communication between one communication device and a plurality of other communication devices,
The plurality of other communication devices include:
First receiving means for receiving data of a plurality of destinations from the one communication device;
A response signal generating means for generating a reception failure response signal when reception of the data of the plurality of destinations fails;
First transmission means for transmitting the response signal to the one communication device,
The one communication device is:
Second transmission means for transmitting the plurality of destination data to the plurality of other communication devices;
Second receiving means for receiving a response signal indicating failure in receiving the data of the plurality of destinations from at least one of the plurality of other communication devices;
A data communication system comprising: a retransmission determination unit that instructs the second transmission unit to retransmit the multi-destination data based on a received failure response signal for the multi-destination data.   The response signal generation means receives the data of the plurality of destinations when the data of the plurality of destinations scheduled to be received cannot be received after a predetermined time based on the information indicating the data of the plurality of destinations scheduled to be received. 16. The data communication system according to claim 15, wherein the data communication system is determined to have failed.   The information indicating the data of the multiple destinations to be received is received in advance by the other communication devices from the one communication device, or is embedded at the beginning and end of the data of the multiple destinations. The data communication system according to claim 16.   18. The retransmission determination unit, when the second reception unit receives a response signal that cannot be restored, determines that it has received a response signal indicating failure in receiving the data of the plurality of destinations. Data communication system.   The retransmission determination unit determines that a response signal indicating failure in receiving the data of the plurality of destinations has been received when interference occurs in the frequency band used for the data communication at the timing of receiving the response signal. The data communication system according to claim 17.   The data communication system according to claim 15, wherein the communication device performs wireless communication.

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