JP4563201B2 - Communication method - Google Patents

Description

  The present invention relates to a data communication method, a data communication apparatus, and a data communication program recording medium, and in particular, data communication that transmits and receives in units of frames by an unbalanced half-duplex HDLC communication method, and further, primary and secondary stations by infrared rays. The present invention relates to a data communication method, a data communication apparatus, and a data communication program recording medium in an IrDA (Infrared Data Association) communication system that performs communication with the data communication program.

  Infrared communication is centered on portable personal terminals such as mobile phones, notebook personal computers, electronic notebooks, etc., and data between these electronic devices that are suitable for carrying or with desktop personal computers, infrared printers, etc. In exchange, it has become popular in recent years. There are IrDA, ASK, and other communication methods in infrared communication. The IrDA method is based on the HDLC communication method, which is a communication method for high-speed and highly efficient transmission mainly between computers. Is a communication protocol that is widely used as a general communication protocol.

  Further, in data transmission in a computer or the like, it is common to use packet exchange for transmitting and receiving packets composed of data of a certain size and information indicating serial numbers and addresses assigned before and after the data. Packets used in the scheme and IrDA communication scheme are called frames and are managed in the IrLAP layer.

  The frame is composed of fields of address (A), control (C), information (I), and FCS, and flags attached before and after, and is used for information (data) transfer. There are an (Information) frame, an S (Supervisory) frame for monitoring control of communication, and a U (Unnumbered) frame used for data communication without connection / disconnection or retransmission in communication.

  Usually, since data to be transmitted cannot be transmitted in one frame in many cases, it is divided into a plurality of frames (I frame or UI frame) and transmitted. The I frame has data to be transmitted in the I field and has a serial number used for checking for missing data, so that highly reliable communication can be realized. The UI frame has data to be transmitted in the I field but does not have a serial number used for checking for missing data. The S frame does not have an I field for holding data, and is used to transmit a reception preparation completion, a busy state, a retransmission request, and the like. Since the U frame does not have a number like an I frame, it is called an unnumbered frame, and is used for setting a communication mode, reporting a response or an abnormal state, and establishing or disconnecting a data link.

  As described above, the IrDA communication method is based on the HDLC communication method. Generally, the communication method includes a full-duplex communication method capable of simultaneously performing transmission and reception, and a half-duplex communication method not performing simultaneously. In the case of the half-duplex communication method, it is necessary to define a signal for switching between transmission and reception.

  In the HDLC system, the full-duplex system can be adopted, but in the case of the IrDA communication system, the baseband modulation infrared ray propagating in the free space is used for data transmission, and two or more stations are in communication range. If they are transmitted simultaneously, infrared interference will occur and normal communication will not be possible. For this reason, the IrDA communication method performs transmission only when infrared rays do not exist within the communication range before establishing a communication link, and periodically exchanges transmission rights between two communicating stations after establishing the communication link. The half-duplex method is used.

  FIG. 6 is a diagram for explaining the application of such a communication method. In the HDLC communication system and the IrDA communication system, what performs transmission or reception is called a “station”. Generally, a primary station that performs data link control for controlling communication, and a secondary station that follows control of the primary station are Is transmitted and received as a command (primary station → secondary station) and a response (secondary station → primary station). Such a method is called an unbalanced communication method. As shown in the figure, a TV, such as a computer, a mobile phone, and an electronic notebook, functions as a station in communication, and can exchange data using infrared as a transmission medium.

  FIG. 7 is a diagram showing frame exchange at the time of connection in these communications. Station A transmits an SNRM (Set Normal Response Packet) frame representing a connection request. At this time, parameters such as the maximum transferable speed at the time of data transfer, the maximum frame length, and the maximum turnaround time of the own station are also transmitted. In response to this, station B transmits a UA (Unnumbered Acknowledgment) frame.

  At this time, similarly, parameters such as the maximum transferable speed at the time of data transfer of the own station, the maximum frame length, and the maximum turnaround time of the own station are also transmitted. By doing this, it is possible to know the maximum transfer speed of the partner station, and determine the maximum transfer speed during communication from the maximum transfer speed of the own station and the maximum transfer speed of the partner station. The transfer is performed at the determined transfer rate.

  By exchanging the maximum frame length, it is possible to know the capacity of the reception buffer of the counterpart station, and it is necessary to transmit a frame with a frame length that is equal to or less than the maximum frame length of the counterpart station. The maximum turnaround time is the maximum value of the time during which the partner station can maintain the transmission right, and is the maximum time during which it is necessary to wait for a reply from the partner station after delegating the transmission right to the partner station. At the time of frame transmission, it is not preferable to transmit the frame beyond the maximum turnaround time of the own station because it may lead to frame collision.

  FIG. 8 is a sequence diagram for explaining a general procedure using an I frame in these communication systems. Here, a case where data divided into a plurality of I frames is transmitted from station A to station B is shown. The window size at this time is 3. First, the primary station A transmits a data frame as an I frame with numbers “0”, “1”, and “2” assigned thereto. When transmitting frames with serial numbers “0” and “1”, the P / F (Pole / Final) bit is set to 0 so that the transmission right is not transferred to the B station as the secondary station. When transmitting the frame with the serial number “2”, the P / F bit is set to 1 in order to transfer the transmission right to the secondary station.

  The B station that has received the frames having the serial numbers “0”, “1”, and “2”, when receiving each frame normally, receives the frame having the serial number “2” with the P / F bit set to “2”. The frame to which the number “3” next to “3” is returned is transmitted, and the meaning of “send the third data” is transmitted. This response frame is an S frame called an RR frame. When the secondary station transmits the RR frame, the P / F bit is set to 1 in order to transfer the transmission right to the primary station.

  The A station confirms the response of the B station, and again assigns serial numbers “3”, “4”, and “5” from the third data and transmits the data. By repeating this procedure as many times as necessary, the accuracy of multi-frame communication can be improved.

  When station B detects an error or missing data, it sends the RR frame with the data number that it wants to retransmit, and station A retransmits it from the data number that it wants to retransmit Is possible. In data transfer using I frames, the number of frames that can be transmitted by the primary station at a time is limited by the window size. In IrDA's IrLAP (Infrared Link Access Protocol) (Ver1.1), the maximum number is seven. ing. For this reason, when a large amount of data is transferred, a response frame is transmitted from the secondary station for each window size. This causes a deterioration in communication efficiency in a communication situation where there is no error.

  FIG. 9 is a signal sequence diagram for explaining a general procedure using a UI frame in these communication methods. Here, a case where data divided into a plurality of UI frames is transmitted from the A station to the B station is shown. In the case of data transfer using a UI frame, since the window size is not limited, the station A can continuously transmit frames during the maximum turnaround time.

  When the maximum turnaround time of station A elapses, station A transmits an RR frame for delegating the transmission right to station B, which is the secondary station. The maximum turnaround time is the time during which a station can maintain the transmission right, and if there is no response from the other station even after the maximum turnaround time of the other station has passed since the transfer right was delegated to the other station The station that transmitted the transmission right delegation frame can know that the transmission right delegation frame has not arrived at the other station. The maximum turnaround time of the partner station can be known by exchanging parameters at the connection probability. In IrLAP, a maximum turnaround time of up to 500 ms is specified.

  The B station to which the transmission right is delegated by the RR frame, when there is no transmission data transfer request in the own station, sets the P / F bit to 1 and transmits the RR frame, thereby the A station which is the primary station Delegate the transmission right to.

  In the data transfer using the UI frame, retransmission is not performed when the I frame is used. However, in a situation where the quality of the communication channel is good and no error occurs, the station A has a maximum time of 500 ms as described above. Continuous frame transmission is possible, leading to improved communication efficiency.

(Frame format)
FIG. 10 shows the frame formats of the I frame, RR frame, and UI frame described above. In the I frame, the least significant bit of the control field of the second byte is set to 0. The serial number of the transmission frame is set in the Ns field. When delegating the transmission right, set the P / F bit to 1, and when not delegating the transmission right, set the P / F bit to 0. In the Nr field, a value obtained by adding 1 to the serial number of I frames that have been normally received normally is set. Transmission data is set in the Information field.

  In the UI frame, the lower 4 bits of the Control field of the second byte are set to “0011”. Similarly to the I frame, the P / F bit is set to 1 when the transmission right is delegated, and is set to 0 when the transmission right is not delegated. It does not have an Ns field that represents a serial number. Transmission data is set in the Information field.

  In the RR frame, the lower 4 bits of the Control field of the second byte are set to “0001”. Similarly to the I frame, the P / F bit is set to 1 when the transmission right is delegated, and is set to 0 when the transmission right is not delegated. In the Nr field, a value obtained by adding 1 to the serial number of consecutively received I frames is set. If the I-frame Ns field is normally received up to 2, and the I-frame with Ns of 3 has failed to be received, the transmission right is transferred to the local station, and then the value of Nr is set to 3 and transmitted. To do. When receiving the RR frame with Nr of 3, the station A can recognize that the reception of the frame with Ns of 3 has failed, and can retransmit the I frame from the frame with Ns of 3. It becomes. Does not have an Information field.

(Image transfer application)
In recent years, there has been proposed an application that uses IrDA to transfer and display image data in a transmitting terminal such as a mobile phone to a receiving terminal such as a TV. In the application, the image data has a data size from several hundred kB to over 1 MB, and it takes a long transfer time. In such an application, it is a condition that the quality of the communication path is good, but the data transfer using the UI frame has less response from the secondary station and the transfer efficiency is higher than the data transfer using the I frame. good.
Japanese Patent Laid-Open No. 11-154908 (Publication date: June 8, 1999)

  However, in the above-described conventional configuration, when data transfer using a UI frame with high transfer efficiency is used, frames are alternately arranged between the primary station and the secondary station so as not to overlap each other. At the time of exchange, when one side is transmitting a frame, the other side transmits a frame due to misidentification, which causes a problem called frame collision.

  That is, FIG. 11 shows a case where data transfer is performed using a UI frame. T601, T603, and T605 are the transmission start times of the first, second, and third UI frames, respectively. T602, T604, and T606 are the first, second, and third UIs, respectively. This is the frame transmission end time. Assume that the maximum turnaround time of station A is reached at timing T609. At the start of transmission of the third UI frame, since the timer value has not reached the maximum turnaround time of station A, station A starts transmission by setting the P / F bit to 0. Although the maximum turnaround time of station A has been reached at the timing of T609, frame transmission is continued because frame transmission has not yet been completed. After completing the third frame transmission at T606, it recognizes that the maximum turnaround time of its own station has been exceeded, and at T607, by setting the P / F bit to 1 and transmitting the RR command, The transmission right is transferred to the B station.

  As described above, in the current IrDA standard, the maximum turnaround time of the local station may be exceeded during frame transmission, and the transmission frame of station A does not reach station B depending on the quality of the communication path. After the transfer right is transferred to the A station, the B station determines that it has the right to transmit after the maximum turnaround time and transmits the frame, which may cause a frame collision. There is.

  In Patent Document 1, an EOF monitoring timer is provided for detecting an identifier indicating the end of a frame when an identifier indicating the end of the frame cannot be received or is affected by other infrared rays. It starts after receiving the identifier indicating the head, and waits for the reception of the identifier indicating the end of the frame, and then finishes monitoring the EOF timer timeout and receiving processing from the slave station, so that the maximum turnaround time is exceeded. A method for not cutting in case is described.

  However, Patent Document 1 does not describe a method for preventing the maximum turnaround time from being exceeded.

  The present invention avoids frame collision by delegating the transmission right to the other station as soon as possible when transmitting a frame whose purpose exceeds the maximum turnaround time of the own station as described above. It is to provide a communication method, a transmission / reception circuit, and a mobile phone.

A first communication method according to the present invention that achieves the above object is a communication that performs frame transmission by a half-duplex communication method using a timer that measures the turnaround time of the local station and a flag that delegates transmission rights. in the method according to the own station is a first frame format having a transmission right, while performing a transmission to the other station, when the transmission is determined to reach the maximum turnaround time of the own station, the transmission right The value of the meaning of delegation is set in the flag for delegating the transmission right, and transmission is performed to the partner station .

  As a result, the above method makes it possible to set a frame that exceeds the maximum turnaround time of the local station as the final transmission frame of the local station, accelerates the timing for delegating the transmission right, and reduces the possibility of frame collision. .

The second communication method according to the present invention that achieves the above object is a communication that performs frame transfer in a half-duplex communication system using a timer that measures the turnaround time of the local station and a flag that delegates transmission rights. In the method, if the value of the timer for measuring the turnaround time has reached a predetermined value shorter than the maximum turnaround time of the own station that has the transmission right and is transmitting to the other station , set the value of the sense to transfer the transmission right to the flag to delegate the transmission right according to a second frame format, and performs frame transmission to the other station.

  As a result, the above method can delegate the transmission right to the partner station before exceeding the maximum turnaround time of the own station, and can suppress the collision of frames.

The third communication method according to the present invention for achieving the above object is to transmit data using a half-duplex communication method using a timer for measuring the turnaround time of the own station and a flag for delegating the transmission right . In the communication method to be performed, if the local station having the transmission right reaches the maximum turnaround time of the local station while performing transmission to the other station according to the third frame format, immediately terminates the transmission frame, according to a fourth frame format immediately thereafter, the frame sets a flag to transfer the transmission right to the means to transfer the transmission right to send to the other station, the local station, the third frame format or from the other station In accordance with the fourth frame format, after receiving the frame meaning to transfer the transmission right, the third frame format is started from the continuation of the previous transmission data. The transmission of frames in accordance with the Tsu preparative and performing the other station.

  As a result, when the above method exceeds the maximum turnaround time of the local station, it is possible to immediately terminate the frame transmission and transfer the transmission right to the partner station, thereby reducing the possibility of a frame collision. Become.

  A fourth communication method according to the present invention that achieves the above object is the communication method according to any one of the first to third methods described above, and is characterized by using infrared rays as a communication medium.

  As a result, the above method eliminates physical contact of a connector or the like, eliminates deterioration of the connection portion, and leads to improvement in convenience.

  A fifth communication method according to the present invention that achieves the above object is the first communication method described above, wherein the first frame format is an IrDA UI frame format. Thereby, the above method enables data transfer based on IrDA.

  The sixth communication method according to the present invention for achieving the above object is the first communication method described above, wherein the time determined to reach the maximum turnaround time of the local station is frame transmission. A value obtained by adding the maximum frame transfer time obtained from the data transfer rate determined at the time of connection and the maximum frame length to the start time exceeds the maximum turnaround time of the own station.

  This eliminates the need for calculating the time to set the P / F bit to 1 for each frame to be transmitted, and simplifies the processing.

  The seventh communication method according to the present invention for achieving the above object is the first communication method described above, wherein the time determined to reach the maximum turnaround time of the local station is frame transmission. The value obtained by adding the frame transfer time obtained from the data transfer rate determined at connection and the frame length of the frame to be transmitted to the start time exceeds the maximum turnaround time of the own station. .

  Thus, in the above method, when the frame is shorter than the maximum frame length and does not exceed the maximum frame length of the local station during transmission, the P / F bit is set to 0, and the frame has the same length as the maximum frame length. Only when it is determined that the maximum turnaround time is exceeded during transmission, the P / F bit can be set to 1, which improves efficiency.

  An eighth communication method according to the present invention for achieving the above object is the second communication method described above, wherein the second frame format is an IrDA RR frame format. To do. Thereby, the above method enables data transfer based on IrDA.

  The ninth communication method according to the present invention for achieving the above-described object is the second communication method described above, wherein the predetermined value is determined from the maximum turnaround time of the own station at the time of connection. It is a value obtained by subtracting the maximum frame transfer time obtained from the determined data transfer rate and maximum frame length.

  Thereby, since the said method does not transmit a frame exceeding the maximum turnaround time, it is possible to suppress frame collision.

  A tenth communication method according to the present invention for achieving the above object is the third communication method described above, wherein the third frame format is an IrDA UI frame format, The frame format is an IrDA RR frame format. Thereby, the above method enables data transfer based on IrDA.

  In the communication method of the present invention, as described above, when it is determined that the maximum turnaround time is exceeded at the time of UI frame transmission, the P / F bit of the frame can be set to 1, and the transmission right can be delegated to the other station. , Leading to suppression of frame collisions.

  In addition, when a data transmission request is generated within the local station, the communication method of the present invention transmits a UI frame if the value obtained by adding the maximum frame transfer time to the timer value is equal to or greater than the maximum turnaround time. Instead, by transmitting the RR frame, it becomes possible to delegate the transmission right to the partner station, leading to suppression of frame collision.

  The communication method of the present invention also terminates UI frame transmission once when the maximum turnaround time is reached during UI frame transmission, transmits an RR frame with the P / F bit set to 1, and sets the transmission right to the other party. After delegating to the station, when the transmission right of the own station is obtained again, the remaining data is transmitted in the UI frame, which leads to suppression of frame collision.

  Each embodiment of a communication method according to the present invention and a transmission / reception circuit using the communication method will be described with reference to FIGS. 1 to 5 as follows. That is, a block diagram showing the first embodiment of the present invention is shown in FIG. In the present embodiment, an IrDA communication method will be described as an example, but the present invention is not limited to this. In addition, each component in the block diagram may be configured by hardware or software. Each function in the block diagram exists in, for example, a mobile phone or a notebook personal computer, but there is no problem with other terminals having the transmission function of the present invention.

  The function of each component will be described below. As shown in FIG. 1, the state machine 701 is a part that manages communication. When connected to a partner station, the state machine 701 notifies the transmission frame generation unit 702 to transmit an SNRM command, and connects the parameters (local station). The maximum transferable speed, maximum frame length, maximum turnaround time of the local station, etc.).

  When there is a connection request from the state machine 701, the transmission frame generation unit 702 generates a transmission frame by putting the value of the connection parameter in the SNRM command and passes it to the transmitter 703. The transmitter 703 is a part that converts an electrical signal in the format of the SNRM command into infrared rays and transmits it. In this case, it becomes LED (light emitting diode) and LD (laser diode). If a communication medium other than infrared rays is still used, the transmitter is also suitable for the communication medium.

  In the first embodiment of the present invention, since the receiver 704 uses infrared rays as a communication medium, for example, it includes a PD (photodiode) and is provided so as to convert the received infrared rays into an electrical signal. Yes. In the case of using a communication medium other than infrared rays, the receiver is also suitable for the communication medium.

  The received frame analysis unit 705 is a part that analyzes the frame received by the receiver 704. For example, if the received frame is a UA response, this is notified to the state machine 701 and the connection parameters in the UA response (maximum transferable speed of the partner device, maximum frame length, maximum turnaround time, etc.) are matched. Be notified.

  The state machine 701 determines the transfer speed at the time of data transfer from the maximum transferable speed of its own station and the maximum transferable speed of the counterpart device, and records it in the transfer speed storage unit 706. Further, the maximum frame length of the partner station is stored in the maximum frame length storage unit 707. At the time of data transfer, a frame length larger than this value cannot be transmitted.

  When the connection with the partner station is completed and a data transfer request is generated within the local station, the state machine 701 passes the transmission data to the transmission frame generation unit 702, and also transmits whether the transmission is an I frame or a UI frame. Notice. In the first embodiment of the present invention, transmission in a UI frame will be described.

  In the communication method of the present invention, the state machine 701 starts communication after resetting the timer 709 when the transmission right is transferred to the local station. Subsequently, when the state machine 701 notifies the transmission frame generation unit 702 of the data transfer request, the state machine 701 calculates the value of the timer 709 from the values stored in the transfer rate storage unit 706 and the maximum frame length storage unit 707. If the value obtained by adding the maximum frame transfer time is larger than the maximum turnaround time, the transmission frame generation unit 702 is notified that the transmission right is delegated, and if it is smaller, the transmission right is not delegated.

  Further, when a data transfer request generated in the state machine 701 is stored, the data length to be transmitted is stored in the transmission frame length storage unit 708, and when the data transfer request is notified to the transmission frame generation unit, the value of the timer 709 is set. If the value obtained by adding the maximum frame transfer time calculated by the values stored in the transfer rate storage unit 706 and the transmission frame length storage unit 708 is larger than the maximum turnaround time, the transmission right is transferred. If not, the transmission frame generation unit 702 may be notified that the transmission right is not delegated.

  In response to a data transfer request from the state machine, the transmission frame generation unit 702 sets the P / F bit to 1 when delegating the transmission right, and the P / F bit when not delegating the transmission right. Is set to 0, and transmission data is transmitted in the UI frame.

  With the above configuration, when transmitting a UI frame within the maximum turnaround time or exceeding the maximum turnaround, the transmission right can be delegated to the other station by setting the P / F bit to 1.

  FIG. 2 is a flowchart showing the operation of the state machine 701 at the time of data transfer according to the first embodiment of the present invention. The flowchart will be described below. Step S801 indicates that the transmission right is delegated to the own station. First, the process proceeds to step S801. Subsequently, step S802 is a step of resetting and starting the timer. After completion, the process proceeds to step S803.

  Step S803 is a step of determining whether or not a data transfer request has occurred within the own station. If it has occurred, the process proceeds to step S804. If it has not occurred, the process proceeds to step S808. Step S804 is a step of determining whether or not the sum of the maximum frame transfer time obtained from the product of the transfer rate and the maximum frame length and the timer value is equal to or less than the maximum turnaround time. If the sum is less than or equal to the maximum turnaround time, the process proceeds to step S805. If the sum exceeds the maximum turnaround time, the process proceeds to step S806.

  Step S805 is a step of setting the transmission right delegation flag to 0 and requesting the transmission frame generation unit 702 to start transmission of the UI frame. After the transmission start request, the process proceeds to step S803. Step S806 is a step of setting the transmission right delegation flag to 1 and requesting the transmission frame generation unit 702 to start transmission of a UI frame. After the transmission start request, the process proceeds to step S809.

Step S807 is a step of setting the transmission right delegation flag to 1 and requesting the transmission frame generation unit to start transmission of the RR frame. After the transmission start request, the process proceeds to step S809.
Step S808 is a step of determining whether or not the timer value has reached the maximum turnaround time. If it has reached, the process proceeds to step S807, and if not, the process proceeds to step S803.

  Step S809 is a step of determining whether or not the transmission right has been delegated to the own station. If it is delegated, the process proceeds to step S801, and if it is not delegated, the process proceeds to step S809.

  By realizing the above-described flowchart, it is possible to delegate the transmission right to the partner station by setting the P / F bit to 1 when transmitting a UI frame within the maximum turnaround time or exceeding the maximum turnaround.

  FIG. 3 is a flowchart showing another operation of the state machine 701 at the time of data transfer according to the first embodiment of the present invention. The flowchart will be described below. Step S901 indicates that the transmission right is delegated to the own station. Transition to step S901. Step S902 is a step of resetting and starting the timer. After completion, the process proceeds to step S903.

  Step S903 is a step of determining whether or not a data transfer request is generated in the own station. If it has occurred, the process proceeds to step S904. If it has not occurred, the process proceeds to step S908. Step S904 is a step of determining whether the sum of the frame transfer time obtained from the product of the transfer rate and the transmission frame length and the timer value is equal to or less than the maximum turnaround time. If the sum is less than or equal to the maximum turnaround time, the process proceeds to step S905. If the sum exceeds the maximum turnaround time, the process proceeds to step S906.

  Step S905 is a step of setting the transmission right delegation flag to 0 and requesting the transmission frame generation unit 702 to start transmission of the UI frame. After the transmission start request, the process proceeds to step S903. Step S906 is a step of setting the transmission right delegation flag to 1 and requesting the transmission frame generation unit 702 to start transmission of the UI frame. After the transmission start request, the process proceeds to step S909.

  Step S907 is a step of setting the transmission right delegation flag to 1 and requesting the transmission frame generation unit 702 to start transmission of the RR frame. After the transmission start request, the process proceeds to step S909. Step S908 is a step of determining whether or not the timer value has reached the maximum turnaround time. If it has reached, the process proceeds to step S907, and if not, the process proceeds to step S903.

  Step S909 is a step of determining whether or not the transmission right is delegated to the own station. If it is delegated, the process proceeds to step S901. If it is not delegated, the process proceeds to step S909.

  By realizing the above-described flowchart, it is possible to delegate the transmission right to the partner station by setting the P / F bit to 1 when transmitting a UI frame within the maximum turnaround time or exceeding the maximum turnaround.

  FIG. 1 is a block diagram showing a second embodiment of the present invention. In the present embodiment, an IrDA communication method will be described as an example, but the present invention is not limited to this. In addition, each component in the block diagram may be configured by hardware or software. Each function of the block diagram exists in, for example, a mobile phone or a notebook personal computer, but there is no problem with other terminals having the transmission function of the present invention. Since the functions of the constituent elements other than the state machine 701 have the same functions as those in the first embodiment of the present invention, their description is omitted.

  When a data transfer request is generated in the own station, the state machine 701 passes transmission data to the transmission frame generation unit 702 and notifies whether transmission is performed using an I frame or transmission using a UI frame. In the second embodiment of the present invention, transmission in a UI frame will be described.

  In the communication method according to the present embodiment, state machine 701 starts after resetting timer 709 when the transmission right is transferred to the local station. Next, when the state machine 701 notifies the transmission frame generation unit 702 of the data transfer request, the state machine 701 calculates the value of the timer 709 from the values stored in the transfer rate storage unit 706 and the maximum frame length storage unit 707. If the value obtained by adding the maximum frame transfer time is greater than the maximum turnaround time, data transmission is not performed and only the transmission right is delegated. The transmission frame generation unit 702 is notified that the delegation is not performed.

  In response to the frame transfer request from the state machine 701, the transmission frame generation unit 702 transmits the RR frame with the P / F bit set to 1 when only transferring the transmission right without performing the data transfer. When data transmission is performed but transmission right is not delegated, the P / F bit is set to 0, and transmission data is transmitted in a UI frame.

  According to said structure, it becomes possible not to perform UI frame transmission exceeding the maximum turnaround time.

  FIG. 4 is a flowchart showing the operation of the state machine 701 at the time of data transfer according to the second embodiment of the present invention. The flowchart will be described below. Step S1001 indicates that the transmission right has been delegated to the own station. First, the process proceeds to step S1001. Step S1002 is a step of resetting and starting the timer. After completion, the process proceeds to step S1003.

  Step S1003 is a step of determining whether or not a data transfer request has occurred within the own station. If it has occurred, the process proceeds to step S1004. If it has not occurred, the process proceeds to step S1008. Step S1004 is a step of determining whether or not the sum of the maximum frame transfer time obtained from the transfer rate and the maximum frame length and the timer value is equal to or less than the maximum turnaround time.

  If it is less than the maximum turnaround time, the process proceeds to step S1005, and if it exceeds the maximum turnaround time, the process proceeds to step S1007. Step S1005 is a step of setting the transmission right delegation flag to 0 and requesting the transmission frame generation unit 702 to start transmission of the UI frame. After the transmission start request, the process proceeds to step S1003.

  Step S1007 is a step of setting the transmission right delegation flag to 1 and requesting the transmission frame generation unit 702 to start transmission of the RR frame. After the transmission start request, the process proceeds to step S1009.

  Step S1008 is a step of determining whether or not the timer has reached the maximum turnaround time. If it has reached, the process proceeds to step S1007, and if not, the process proceeds to step S1003.

  Step S1009 is a step of determining whether or not the transmission right is delegated to the own station. If it is delegated, the process proceeds to step S1001, and if it is not delegated, the process proceeds to step S1009.

  By realizing the above-described flowchart, it is possible not to perform UI frame transmission exceeding the maximum turnaround.

  A block diagram showing a third embodiment of the present invention is shown in FIG. In the present embodiment, an IrDA communication method will be described as an example, but the present invention is not limited to this. In addition, each component in the block diagram may be configured by hardware or software. Each function of the block diagram exists in, for example, a mobile phone or a notebook personal computer, but there is no problem with other terminals having the transmission function of the present invention. Since the functions of the constituent elements other than the state machine 701 have the same functions as those in the first embodiment of the present invention, description thereof will be omitted.

  When a data transfer request is generated in the own station, the transmission data is transferred to the transmission frame generation unit 702 and notified whether transmission is performed using an I frame or transmission using a UI frame. In the third embodiment of the present invention, transmission in a UI frame will be described.

  When the transmission right is transferred to the local station, the state machine 701 starts after resetting the timer 709. When the data transfer request is notified to the transmission frame generation unit 702, if the value of the timer 709 has reached the maximum turnaround time, data transmission is not performed and only the transmission right is delegated. Data is transmitted, and the transmission frame generation unit 702 is notified that the transmission right is not delegated.

  In response to the frame transfer request from the state machine 701, the transmission frame generation unit 702 transmits the RR frame with the P / F bit set to 1 when only transferring the transmission right without performing the data transfer. When data transmission is performed but transmission right is not delegated, the P / F bit is set to 0, and transmission data is transmitted in a UI frame.

  The state machine 701 monitors the value of the timer 709 after notifying the transmission frame generation unit 702 of the start of transmission. When the value of the timer 709 reaches the maximum turnaround time, the transmission frame generation unit 702 is notified to that effect, and the transmission frame generation unit 702 that has received the notification once ends the UI frame transmission at this point, and immediately The RR frame is transmitted with the P / F bit set to 1.

  Thereafter, when the frame received by the receiver 704 is analyzed by the received frame analysis unit 705, when the state machine 701 recognizes that the P / F bit is 1 and the transmission right has been transferred to the own station, the transmission frame In response to notifying the generation unit 702 that the previous data is to be transmitted, the transmission frame generation unit 702 sets the P / F bit to 0 and transmits the UI frame from the previous data.

  With the above configuration, when the turnaround time is reached during UI frame transmission, it is possible to transmit an RR frame with the P / F bit set to 1, and to suppress frame collision.

  FIG. 5 is a flowchart showing the operation of the state machine 701 at the time of data transfer according to the third embodiment of the present invention. The flowchart will be described below. Step S1101 indicates that the transmission right has been delegated to the own station. First, the process proceeds to step S1101. Step S1102 is a step of resetting and starting the timer. After completion, the process proceeds to step S1103.

  Step S1103 is a step of determining whether or not a data transfer request has occurred within the own station. If it has occurred, the process proceeds to step S1104. If it has not occurred, the process proceeds to step S1108. Step S1104 is a step of determining whether or not the timer value has reached the maximum turnaround time. If not reached, the process proceeds to step S1105. If reached, the process proceeds to step S1107.

  Step S1105 is a step of setting the transmission right delegation flag to 0 and requesting the transmission frame generation unit to start transmission of the UI frame. After the transmission start request, the process proceeds to step S1110. Step S1107 is a step of setting the transmission right transfer flag to 1 and requesting the transmission frame generation unit to start transmission of the RR frame. After the transmission start request, the process proceeds to step S1109.

  Step S1108 is a step of determining whether or not the timer value has reached the maximum turnaround time. If reached, the process proceeds to step S1107, and if not reached, the process proceeds to step S1103. Step S1109 is a step of determining whether or not the transmission right is delegated to the own station. If it is delegated, the process proceeds to step S1101, and if it is not delegated, the process proceeds to step S1109.

  Step S1110 is a step of determining whether or not the timer value has reached the maximum turnaround time during frame transmission. If reached, the process proceeds to step S1111. If the transmission ends before reaching, the process proceeds to step S1103.

  Step S1111 is a step of making a transmission end request to the transmission frame generation unit 702, setting the transmission right delegation flag to 1 in the transmission frame generation unit 702 after once transmitting the UI frame, and making an RR frame transmission request It is. After completion, the process proceeds to step S1112.

  Step S1112 is a step of determining whether or not the transmission right is delegated to the own station. If it is delegated, the process proceeds to step S1113. If it is not delegated, the process proceeds to step S1112.

  Step S1113 is a step of requesting the transmission frame generation unit to transmit the remaining data of the previous UI frame by setting the transmission right transfer flag to 0 after resetting the timer. After completion, the process proceeds to step S1103.

  By realizing the above flowchart, it is possible to transmit an RR frame with the P / F bit set to 1 when the maximum turnaround time is reached during UI frame transmission, and to suppress frame collision. Become.

  In addition, each communication method shown in each of the above embodiments can be a program described so as to be executable by a computer, and a CD-R that stores the program so as to be readable by the computer. It can also be distributed to the market as a recording medium.

  The communication method, transmission / reception circuit, and mobile phone of the present invention can suppress the collision of frames at the time of communication between each other and can facilitate the above-mentioned communication. Therefore, the communication method, particularly a small communication field such as a mobile phone is suitable. Available.

It is a block diagram which shows the 1st Embodiment of this invention, 2nd Embodiment, and 3rd Embodiment. It is a flowchart which shows an example in 1st Embodiment of the communication method which concerns on this invention. It is a flowchart which shows the other example in the said 1st Embodiment. It is a flowchart which shows 2nd Embodiment of the communication method which concerns on this invention. It is a flowchart which shows 3rd Embodiment of the communication method which concerns on this invention. It is a block diagram for demonstrating communication between the stations in the data communication by a prior art. It is a signal sequence diagram for demonstrating the connection between the stations in the data communication by a prior art. It is a signal sequence diagram which shows the data transfer using the I frame by a prior art. It is a signal sequence diagram which shows the data transfer using UI frame by a prior art. It is each frame format diagram of an I frame, UI frame, and RR frame according to the prior art. FIG. 10 is a signal sequence diagram illustrating a case where a maximum turnaround time is exceeded during data transfer using a UI frame according to a conventional technique.

Explanation of symbols

T601 First UI frame transmission start time
T602 First UI frame transmission end time
T603 Second UI frame transmission start time
T604 Transmission end time of the second UI frame
T605 Third UI frame transmission start time
T606 Third UI frame transmission end time
T607 RR frame transmission start time
T608 RR frame transmission end time
T609 Maximum turnaround time
701 state machine
702 Transmission frame generator
703 transmitter
704 receiver
705 Received frame analysis unit
706 Transfer rate storage
707 Maximum frame length storage
708 Transmission frame length storage
709 timer

Claims (10)

In a communication method in which frame transmission is performed by a half-duplex communication method using a timer for measuring the turnaround time of the own station and a flag for delegating a transmission right,
Meaning delegating the transmission right when it is determined that the transmission reaches the maximum turnaround time of the local station while the local station having the transmission right performs transmission to the other station according to the first frame format. A value is set as a flag for delegating the transmission right, and transmission is performed to the partner station. In a communication method in which frame transfer is performed by a half-duplex communication method using a timer for measuring the turnaround time of the own station and a flag for delegating a transmission right,
If the value of the timer for measuring the turnaround time has reached a predetermined value shorter than the maximum turnaround time of the own station that has the transmission right and is transmitting to the other station, the second A communication method comprising: transmitting a frame to the partner station by setting a value for delegating a transmission right to a flag for delegating the transmission right according to a frame format. In a communication method that performs data transmission by a half-duplex communication method using a timer that measures the turnaround time of the local station and a flag that delegates transmission rights,
If the local station having the transmission right reaches the maximum turnaround time of its own station while transmitting to the other station in accordance with the third frame format, it immediately ends the transmission frame and immediately after the fourth frame In accordance with the frame format of the above, a frame in which the flag for delegating the transmission right is set to the meaning of delegating the transmission right is transmitted to the partner station,
After the local station receives a frame meaning to delegate the transmission right according to the third frame format or the fourth frame format from the partner station, it follows the third frame format from the continuation of the previous transmission data. A communication method characterized by transmitting a transmitted frame to the other station.   4. The communication method according to claim 1, wherein infrared is used as a communication medium.   2. The communication method according to claim 1, wherein the first frame format is an IrDA UI frame format.   2. The communication method according to claim 1, wherein the time determined to reach the maximum turnaround time of the own station is obtained from a data transfer rate determined at connection and a maximum frame length at a frame transmission start time. A communication method characterized in that a value obtained by adding a maximum frame transfer time exceeds a maximum turnaround time of the local station.   2. The communication method according to claim 1, wherein the time determined to reach the maximum turnaround time of the local station is a frame transmission start time, a data transfer rate determined at connection, and a frame to be transmitted. A communication method characterized in that the value obtained by adding the frame transfer time obtained from the frame length of the frame exceeds the maximum turnaround time of the local station.   3. The communication method according to claim 2, wherein the second frame format is an IrDA RR frame format.   3. The communication method according to claim 2, wherein the predetermined value is a maximum frame transfer time obtained from a data transfer rate and a maximum frame length determined at connection from a maximum turnaround time of the local station. A communication method characterized by being a subtracted value.   4. The communication method according to claim 3, wherein the third frame format is an IrDA UI frame format, and the fourth frame format is an IrDA RR frame format. Method.

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