JP2008154087A - Communication system and communication control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malfunctions of each terminal even when a communication network is constituted so that an old terminal which operates according to the existing old protocol and a new terminal adopting a new protocol formed by adding modification to the old protocol are mixed. <P>SOLUTION: This communication system is provided with a control part 160 which performs control according to a second standard located in higher order of a first predetermined standard regarding a control signal transmission protocol for communication, wherein the control part 160 generates a first signal out of the first standard so that a receiving part of a partner terminal which operates according to the first standard generates an error when a control signal is transmitted according to the second standard and generates a second signal out of the first standard as a response signal so that the receiving part of the partner terminal generates the error when the control signal from the partner terminal which operates according to the first standard is received. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication apparatus and a communication control method applicable to a communication system such as a third generation mobile communication system (IMT-2000).

  For example, a standard for the 3G-324 protocol used in the real-time communication of the third generation mobile communication system is defined by the third generation partnership project (3GPP). Accordingly, various terminal products that perform communication operations in accordance with this standard are manufactured by various companies.

  In the 3G-324 protocol, when a control signal is transmitted, the control signal is transmitted by a protocol called SRP (Simple Retransmission Protocol) or NSRP (Numbered SRP) obtained by extending SRP. In this protocol, after one control signal is transmitted, control is performed so as to transmit the next data after receiving a reception response from the other party.

For example, Patent Document 1 discloses a conventional technique somewhat related to the present invention. In this prior art, the transmitting side adds the error with different error patterns to the same data and transmits it, and the receiving side solves the received data error and selects the most reliable data by majority voting. Propose to treat as.
JP 2003-324733 A

  However, in the currently standardized 3G-324 protocol, when a plurality of control signals are to be transmitted, it is necessary to wait for a response from the partner each time, and a plurality of control signals are transmitted. In order to do this, the operation must be repeated many times. Therefore, there is a problem that it takes a lot of time to transmit all data.

  However, since this protocol has already been established as a standard and many products have already been made, it is very difficult to change such a control signal transmission protocol.

  That is, when a new terminal that operates according to a new protocol is manufactured, an old terminal that operates according to the conventional protocol and a new terminal that operates according to the new protocol are mixed on a common communication network. Operates without considering a new protocol, so it is highly likely that the operation of each terminal will be abnormal. Because of such protocol limitations, it has been impossible to improve the communication capability of the terminal by improving the protocol.

  Even if the communication network is configured so that an old terminal that operates according to an existing old protocol and a new terminal that adopts a new protocol obtained by modifying the old protocol are mixed, each terminal An object of the present invention is to provide a communication device and a communication control method capable of preventing malfunction of the communication.

  A first invention (Claim 1) is a communication apparatus that communicates between a plurality of communication stations in accordance with a protocol defined in advance, and relates to a control signal transmission protocol for communication that is defined in advance as a first standard. A control unit that performs control in accordance with a second standard located above the control terminal, and when the control unit transmits a control signal in accordance with the second standard, If the receiving unit generates a first signal out of the first standard so that an error occurs, and receives a control signal from a partner terminal operating in accordance with the first standard, the partner A second signal that is out of the first standard is generated as a response signal so that the receiving unit of the terminal generates an error.

  In the first invention, an attempt is made to execute a control signal transmission protocol between a first terminal (new terminal) operating according to the second standard and a second terminal (old terminal) operating according to the first standard. In this case, since the first terminal transmits a signal out of the first standard as the control signal, the receiving unit of the second terminal that has received the control signal detects a reception error. Therefore, the second terminal regards the control signal from the first terminal as a meaningless signal as well as noise and discards it. In addition, even when a control signal from the second terminal arrives at the first terminal, the first terminal receives the control signal because it transmits a signal outside the standard of the first standard as a response. The receiving unit of the second terminal detects a reception error.

  Therefore, the control signal sent by the first terminal does not have a special influence on the operation of the second terminal, and the control signal sent by the second terminal also has a special influence on the operation of the first terminal. Therefore, even if the new terminal and the old terminal are mixed, the occurrence of malfunction is avoided.

  According to a second invention (Claim 2), in the first invention, the control unit is configured so that a receiving unit of a counterpart terminal operating according to the first standard generates a predetermined fixed pattern error. A first signal and a second signal are generated.

  In the second aspect of the invention, the receiving unit of the counterpart terminal generates an error of a predetermined fixed pattern by the first signal and the second signal. Therefore, it is ensured regardless of the type and content of the control signal to be transmitted. An error can occur.

  According to a third invention (Claim 3), in the second invention, the control unit performs a logical operation on data of a specific area of a predetermined control signal frame and a predetermined constant, and outputs the result of the first signal or It outputs as a 2nd signal, It is characterized by the above-mentioned.

  For example, the value of each bit in the first signal or the second signal can be controlled by the content of the constant by performing an exclusive OR operation in bit units, so that the control signal to be transmitted Regardless of the type and content, a signal outside the standard with respect to the first standard can be reliably generated, and an error can be reliably generated in the counterpart terminal.

  A fourth invention (Claim 4) is a communication device that communicates between a plurality of communication stations in accordance with a protocol defined in advance, and relates to a control signal transmission protocol for communication that is defined in advance as a first standard. A control unit that performs control in accordance with a second standard located above the control terminal, and when the control unit transmits a control signal in accordance with the second standard, Generating at least a part of information required by the first standard as a first signal outside the standard of the first standard so that the receiving unit generates an error. To do.

  For example, H.M. In an SRP frame of a control signal defined by the H.324 standard, a header and a sequence number are required at the beginning of the frame. Therefore, if the header, which is a part of the SRP frame, is deleted and transmitted, the partner terminal recognizes it as a reception error because necessary information is missing in the received frame. Therefore, as in the first invention, the occurrence of malfunction is avoided even if the new terminal and the old terminal are mixed. When the new terminals communicate with each other, a correct control signal frame can be reproduced by prescribing the protocol so as to complement the missing information in the received frame.

  According to a fifth invention (Claim 5), in any one of the first invention and the fourth invention, a video processing unit for encoding / decoding video information and an encoding / decoding of audio information. An audio processing unit, and a wireless communication unit that transmits and receives a signal obtained by multiplexing the signal of the video processing unit and the signal of the audio processing unit as a radio signal are further provided.

  In the fifth aspect, similarly to the third generation mobile communication system, a radio signal in which video information and audio information are multiplexed can be transmitted and received, so that it can be used for mobile communication such as a videophone.

  A sixth invention (Claim 6) is a communication control method for communicating between a plurality of communication stations according to a protocol defined in advance, and controls a control signal transmission protocol for communication of each communication station. When the control unit performs control in accordance with a second standard positioned at a higher level than the first standard defined in advance, when transmitting a control signal from the own station to the counterpart terminal in accordance with the second standard, It is characterized in that the first signal outside the standard of the first standard is generated so that the receiving unit of the counterpart terminal operating according to the first standard generates an error.

  By applying the method of the sixth invention to a predetermined communication system, the same result as that of the first invention can be obtained.

  According to a seventh invention (invention 7), in the sixth invention, a control unit for controlling a control signal transmission protocol for communication of each communication station is located above the first standard defined in advance. When the control is performed according to the second standard, when the control signal is received from the counterpart terminal operating according to the first standard, the first standard is set so that the receiving unit of the counterpart terminal generates an error. The second signal outside the standard is generated as a response signal.

  In the seventh invention, even if the counterpart terminal transmits the control signal first, it is possible to prevent the malfunction.

  According to the present invention, even when configuring a communication network so that an old terminal that operates in accordance with an existing old protocol and a new terminal that adopts a new protocol with modifications to the old protocol are mixed, It is possible to prevent a malfunction from occurring in each terminal. Accordingly, it is possible to introduce a communication device that operates according to a new protocol different from the old protocol, thereby improving the communication performance.

(First embodiment)
One embodiment relating to a communication apparatus and a communication control method of the present invention will be described below with reference to FIGS.

  FIG. 1 is a sequence diagram illustrating an example of main operations of the communication apparatus and communication operations with other stations in the first embodiment. FIG. 2 is a block diagram illustrating a configuration example of the communication apparatus. FIG. 3 is a flowchart showing a detailed operation at the time of reception of the communication apparatus in the first embodiment. FIG. 4 is a sequence diagram illustrating an example of a communication operation between the communication apparatus and another station according to the first embodiment. FIG. 5 is a sequence diagram illustrating an example of a communication operation between the communication apparatus and another station according to the first embodiment. FIG. 6 is a sequence diagram illustrating an example of a communication operation with another station having the same function as the communication device according to the first embodiment. FIG. 7 is a sequence diagram illustrating an example of a communication operation with another station having the same function as the communication device according to the first embodiment. FIG. 8 is a schematic diagram illustrating a data configuration of a control signal handled by the communication apparatus according to the first embodiment.

  In this mode, communication is performed on a communication network in which a communication terminal of a third generation mobile communication system that performs communication using the 3G-324 protocol defined by the third generation partnership project (3GPP) exists. It is assumed that the present invention is applied to a communication device such as a mobile phone terminal. Of course, the present invention can also be applied to devices other than mobile phone terminals as long as they can apply the same communication protocol.

  In this embodiment, it is assumed that the wireless communication terminal 100 configured as shown in FIG. 2 is used as a communication apparatus that implements the present invention. Referring to FIG. 2, the wireless communication terminal 100 includes a wireless unit 110, a multiplexing unit 120, a video encoding / decoding unit 130, an audio encoding / decoding unit 140, a control signal generation unit 150, and an error assignment. / Removal unit 160 and control unit 170.

  Radio section 110 performs radio communication with a radio base station of a mobile communication system to which this terminal belongs, and secures a line for communication with other stations. The multiplexing unit 120 multiplexes signals such as video and audio to be transmitted, and separates and outputs video signals and audio signals included therein from the multiplexed received signals.

  The video encoding / decoding unit 130 restores a reproducible video by encoding video information to be transmitted or decoding the received video information. The audio encoding / decoding unit 140 encodes audio information to be transmitted or decodes the received audio information to restore reproducible audio.

  The control signal generation unit 150 generates various control signals necessary for communication between the own station and another station. The control information to be generated is determined according to a control signal transmission protocol defined in advance by the standard.

  In wireless communication terminal 100 of this form, it is assumed that a new protocol positioned above the 3G-324 protocol that already exists as a standard is adopted as the control signal transmission protocol. As will be described later, this new protocol causes a problem even when an existing terminal adopting the existing 3G-324 protocol as a counterpart terminal (hereinafter referred to as an existing terminal or SRP terminal) coexists on the same communication network. The content of control is devised so that there is no. In other words, the counterpart terminal that exchanges control signals with the local station may be a terminal that supports the same new protocol as the local station, or may be an existing terminal.

  The error adding / removing unit 160 intentionally changes the error to be transmitted to the other party terminal so that the other terminal, which is an existing terminal, generates a specific error (error addition). Processing). Further, when the error giving / removal unit 160 receives the control signal subjected to the error giving process, the error giving / removing unit 160 removes the error from the received signal and restores the original control signal. The control unit 170 controls the entire terminal of the local station and performs processing so that communication can be performed between the local station and the partner terminal according to a predetermined protocol.

  The actual control signal is configured as shown in FIG. For example, when performing videophone communication, capability exchange information or the like is generated as function information 10 representing the contents of the control signal.

  A control signal frame 20 is configured by adding ID information, a sequence number (Seq No.), and an error detection code FCS (Frame Check Sequence) to the function information 10. The control signal frame 20 is configured as a frame conforming to the standard 3G-324 protocol.

  The error addition / removal unit 160 generates an altered control signal frame 20B by performing error addition processing on the control signal frame 20. For example, an exclusive OR bit operation (XOR) with a predetermined constant (for example, 0x1E: hexadecimal notation) is performed on N bytes from the head of the control signal frame 20, and the result is changed to the control signal frame. Output as 20B. The changed control signal frame 20B is transmitted to the counterpart terminal via the multiplexing unit 120 and the radio unit 110.

  When the terminal corresponding to the new protocol receives the changed control signal frame 20B, the error adding / removing unit 160 in the receiving terminal removes the error from the control signal frame 20B, and the control signal frame 20 is displayed. Restore. Specifically, the exclusive OR bit operation (XOR) with the same constant (for example, 0x1E) as the transmission side is performed on N bytes from the head of the control signal frame 20B, and the result is output as the control signal frame 20 To do. Therefore, control signals can be correctly transferred between terminals compatible with the new protocol.

  On the other hand, when the existing terminal receives the changed control signal frame 20B, the content of the N bytes from the beginning is a non-standard value (abnormal value) of the 3G-324 protocol. The existing terminal considers the received modified control signal frame 20B as an error or mere noise and discards it. Therefore, even when a control signal is exchanged between a terminal compatible with the new protocol and an existing terminal, a problem due to a difference in protocol does not occur.

  Next, a specific communication control sequence will be described. In FIG. 1, it is assumed that a control signal is exchanged between the wireless communication terminal 100 which is a terminal corresponding to the above-described new protocol and the wireless communication terminal 200 which is an existing terminal.

  In FIG. 1, the wireless communication terminal 100 creates an SRP (more precisely NSRP) frame corresponding to the control signal frame 20 of FIG. 8 in step S11. The SRP frame is a data frame whose configuration is defined by a standard.

  In step S12 of FIG. 1, the wireless communication terminal 100 uses the exclusive OR bit of the ID information (that is, the header) and the sequence number (Seq No.) that are present in the head region of the SRP frame and a constant (0x5b) that is predetermined. An operation (XOR) is performed, and the result is output as a WNSRP frame (frame corresponding to the new protocol).

  In step S13, either the SRP frame with the sequence number # 0 or the WNSRP frame with the sequence number # 0 is transmitted to the radio communication terminal 200 that is the counterpart terminal.

  On the other hand, since the wireless communication terminal 200 is an existing terminal, an SRP frame is transmitted in step S21 of FIG.

  In step S22 of FIG. 1, the wireless communication terminal 200 processes the received control signal frame. If the received control signal frame is an SRP frame conforming to the standard, the contents of the SRP frame are examined and the operation specified by the protocol is executed. On the other hand, when the wireless communication terminal 200 receives a WNSRP frame from the wireless communication terminal 100, the content of this frame is out of the standard value range, so that it is assumed that a reception error has occurred, and the wireless communication terminal 200 discards the WNSRP frame.

  When the wireless communication terminal 200 receives the SRP frame, the wireless communication terminal 200 transmits a response control signal frame (SRP Res Seq # 0) in subsequent step S23.

  On the other hand, the wireless communication terminal 100 processes the control signal frame transmitted from the counterpart terminal in step S14 in FIG. In step S14, an exclusive OR bit operation (XOR) with a predetermined constant (0x5b) is added to the ID information (that is, the header) and the sequence number (Seq No.) existing in the head region of the received control signal frame. Perform and examine the results. When the transmission source is an existing terminal such as the wireless communication terminal 200, an SRP frame is received. However, when the above calculation process is performed on the SRP frame, an error is added as in step S12. The Therefore, in step S14, it is possible to identify whether the counterpart terminal is a terminal (WNSRP terminal) or an existing terminal (SRP terminal) compatible with the new protocol by checking whether an error has occurred in the control signal frame after the arithmetic processing. .

  When the wireless communication terminal 100 receives a control signal frame from the WNSRP terminal, it transmits a control signal frame (WNSRP Res Seq # 0) in response in the next step S15.

  By the way, there is a possibility that noise may be added or the signal may be deformed in the transmission path from the transmission station to the reception station, so that a control signal frame that does not include an error is transmitted. In some cases, an error may occur at the receiving station.

  In the operation example illustrated in FIG. 4, it is assumed that an error has occurred on the transmission path in the control signal frame transmitted by the wireless communication terminal 100 in step S13. However, when a WNSRP frame is transmitted as a control signal frame, information that causes an error in the protocol handled by the wireless communication terminal 200 that is an existing terminal is added in advance. Therefore, when an error further occurs on the transmission path in the WNSRP frame to which an error is added on the transmission side, the two errors are offset and a WNSRP frame without an error reaches the wireless communication terminal 200 (referred to as occurrence of emulation). There is.

  Therefore, in step S22 of FIG. 4, when an SRP frame is received, an error that has occurred on the transmission path is detected by the receiving unit, so this SRP frame is regarded as an invalid frame and discarded. When a WNSRP frame is received and emulation occurs due to an error that has occurred on the transmission path, the WNSRP frame is recognized as an error-free SRP frame and processed.

  Therefore, in the example shown in FIG. 4, even if the wireless communication terminal 100 transmits a WNSRP frame with an error added, this frame is not discarded on the wireless communication terminal 200 side, and the wireless communication terminal 200 returns a response SRP frame. It will be. However, even in that case, the wireless communication terminal 100 can recognize that the counterpart wireless communication terminal 200 is an SRP terminal from the content of the response SRP frame (performs the same processing as S14), and thus malfunction occurs. It can respond so that there is not.

  In the operation example illustrated in FIG. 5, it is assumed that an error has occurred on the transmission path in the control signal frame (SRP frame) transmitted by the wireless communication terminal 200 in step S21. In this case, the wireless communication terminal 100 processes an SRP frame in which an error has occurred on the transmission path, and when emulation occurs, the received SRP frame is erroneously recognized as a WNSRP frame.

  Accordingly, in step S15 of FIG. 5, the wireless communication terminal 100 generates a response WNSRP frame and transmits it to the wireless communication terminal 200. However, since the WNSRP frame transmitted here is pre-added with information that causes an error in the protocol handled by the existing wireless communication terminal 200, the wireless communication terminal 200 transmits the received WNSRP frame to the WNSRP frame. In step S24, it is discarded as an error.

  On the other hand, in each operation example shown in FIGS. 6 and 7, it is assumed that communication is performed between the same types of wireless communication terminals 100 (A) and 100 (B). That is, an operation in the case where communication is performed between WNSRP terminals (100) corresponding to the new protocol is shown. 6 assumes a case where no error occurs in the frame on the transmission path, and FIG. 7 assumes a case where an error occurs in the frame on the transmission path. 6 and 7, processes corresponding to the steps in FIG. 1 are denoted by the same reference numerals.

  In FIG. 6, the radio communication terminal 100 (A) creates an SRP (more precisely NSRP) frame corresponding to the control signal frame 20 of FIG. 8 in step S11. Also, in the next step S12, the radio communication terminal 100 (A) is exclusive of the constant (0x5b) predetermined for the ID information (that is, the header) and the sequence number (Seq No.) existing in the head area of the SRP frame. Logical OR operation (XOR) is performed, and the result is output as a WNSRP frame (frame corresponding to the new protocol).

  In step S13, either the SRP frame with the sequence number # 0 or the WNSRP frame with the sequence number # 0 is transmitted to the radio communication terminal 100 (B) that is the counterpart terminal.

  On the other hand, the wireless communication terminal 100 (B) also executes control corresponding to the new protocol. That is, the wireless communication terminal 100 (B) performs the same processes as the steps S11, S12, S13, S14, and S15 in the wireless communication terminal 100 (A) in steps S11B, S12B, S13B, S14B, and S15B, respectively. .

  Therefore, regardless of whether the wireless communication terminal 100 (A) transmits either the SRP frame or the WNSRP frame in step S13, the wireless communication terminal 100 (B) determines whether the received frame is an SRP frame or a WNSRP frame. Whether it exists can be correctly recognized in step S14B. Then, the wireless communication terminal 100 (B) generates a response SRP frame if the received frame is an SRP frame, and generates a response WNSRP frame if the received frame is a WNSRP frame in step S15B. Transmit to the radio communication terminal 100 (A).

  Therefore, when communication is performed between the wireless communication terminal 100 (A) and the wireless communication terminal 100 (B) that support the new protocol, communication is performed using either the SRP frame or the WNSRP frame. The transmitted frame can be correctly recognized.

  In the operation example illustrated in FIG. 7, it is assumed that an error has occurred on the transmission path for the control signal frame transmitted by the wireless communication terminal 100 (A) in step S13.

  Since the wireless communication terminal 100 (B) supports the new protocol in the same manner as the wireless communication terminal 100 (A), the wireless communication terminal 100 (B) distinguishes between the SRP frame and the WNSRP frame in step S14B of FIG. be able to. However, in the example of FIG. 7, since a frame in which an error has occurred on the transmission path is received, if the received frame is an SRP frame, it is recognized as an error and discarded. If the received frame is a WNSRP frame, the WNSRP frame may be erroneously recognized as an SRP frame due to the occurrence of emulation.

  Therefore, in the example illustrated in FIG. 7, when the wireless communication terminal 100 (A) transmits the WNSRP frame, the wireless communication terminal 100 (B) is compatible with the WNSRP frame even though the wireless communication terminal 100 (A) supports the WNSRP frame. Generates a response SRP frame in step S15B and transmits it to the radio communication terminal 100 (A). That is, at this time, the wireless communication terminal 100 (B) operates in an existing operation mode (SRP protocol) that is not a new protocol.

  However, when the wireless communication terminal 100 (B) subsequently receives the WNSRP frame from the wireless communication terminal 100 (A), the wireless communication terminal 100 (B) determines the wireless communication terminal 100 (A) from the contents of the WNSRP frame. Since the wireless communication terminal 100 (B) can recognize that it corresponds to the new protocol, it can switch from the operation mode corresponding to the SRP protocol to the operation mode corresponding to the new protocol in step S16.

  Details of the operation when the wireless communication terminal 100 corresponding to the new protocol receives the control signal frame are shown in FIG. The operation of FIG. 3 will be described below. In FIG. 3, A [0] and A [1] represent memories that hold a part of the contents of the received control signal frame (SRP command frame). Further, “==” in the figure means checking whether or not the contents on the right side and the contents on the left side match.

  When receiving the control signal frame, the wireless communication terminal 100 first executes step S31. In step S31, whether the value of the memory A [0] holding the header data (corresponding to “ID” shown in FIG. 8) at the beginning of the received control signal frame matches a predetermined value (SRP_DLCI) Check for no. If they match, the process proceeds to step S32, and if they do not match, the process proceeds to step S35.

  In step S32, the presence or absence of a transmission error in this frame is checked using the error detection code FCS added to the received control signal frame. If no transmission error is found, the process proceeds to the next step S34, and a response is transmitted to the partner station using the SRP frame. If a transmission error is found, the process proceeds to step S40 and the received data of this frame is discarded.

  For example, when the above-described WNSRP frame is transmitted as a control signal frame from the other station, an error is added to the WNSRP frame on the transmission side, so that the value of the memory A [0] is determined in advance in step S31 described above. Since the value (SRP_DLCI) does not match, the process proceeds to step S35.

  In step S35, the same process as the process performed by the transmission-side error adding / removal unit 160 is performed on the received control signal frame. That is, the value of the memory A [0] that holds the data of the header (corresponding to “ID” in FIG. 8) at the head of the received control signal frame, and a predetermined constant (0x5b: the same value as that on the transmission side) Are obtained, and the result is stored in the memory A [0]. Further, an exclusive OR bit operation between the value of the memory A [1] holding the data of the sequence number (Seq No.) following the header and a predetermined constant (0x5b: the same value as that on the transmission side) is performed, The result is stored in the memory A [1].

  That is, by executing Step S35, it is possible to remove the error added to the control signal frame on the transmission side and restore the content of the original control signal frame. Therefore, in the next step S36, the same comparison process as in step S31 is performed again. That is, it is checked whether or not the value of the memory A [0] matches a predetermined value (SRP_DLCI). If they match, the process proceeds to step S37, and if they do not match, the process proceeds to step S41.

  In step S37, the presence or absence of a transmission error in this frame is checked using the error detection code FCS added to the received control signal frame. If no transmission error is found, the process proceeds to step S39 through step S38, and a response is transmitted to the other station using the WNSRP frame. An error is added to the WNSRP frame transmitted as a response in step S39 using the error adding / removing unit 160 as in the case of transmitting the command first. If a transmission error is found, the process proceeds to step S40 and the received data of this frame is discarded.

  In step S41, whether or not the value of the memory A [0] holding the header data (corresponding to “ID” in FIG. 8) at the head of the received control signal frame matches a predetermined value (NSRP_response). Find out. If they match, the process proceeds to step S42, and if they do not match, the process proceeds to step S45.

  In step S42, the presence or absence of a transmission error in this frame is checked using the error detection code FCS added to the received control signal frame. If no transmission error is found, the process proceeds to step S44 through step S43, and the partner terminal is recognized as a terminal (NSRP terminal) compatible with the “NSRP” protocol. If a transmission error is found, the process proceeds to step S40 and the received data of this frame is discarded.

  In step S45, whether or not the value of the memory A [0] holding the header data (corresponding to “ID” in FIG. 8) at the head of the received control signal frame matches a predetermined value (SRP_response). Find out. If they match, the process proceeds to step S46, and if they do not match, the process proceeds to step S49.

  In step S46, the presence or absence of a transmission error in this frame is checked using the error detection code FCS added to the received control signal frame. If no transmission error is found, the process proceeds to step S48 through step S47 and recognizes that the partner terminal is a terminal (SRP terminal) compatible with the “SRP” protocol. If a transmission error is found, the process proceeds to step S40 and the received data of this frame is discarded.

  In step S49, the same process as step S35 is performed again. That is, the value of the memory A [0] holding data of the header (corresponding to “ID” in FIG. 8) at the head of the control signal frame processed in step S35 and a predetermined constant (0x5b: transmission) Bit value of exclusive OR with the same value on the side) and the result is stored in the memory A [0]. Further, an exclusive OR bit operation between the value of the memory A [1] holding the data of the sequence number (Seq No.) following the header and a predetermined constant (0x5b: the same value as that on the transmission side) is performed, The result is stored in the memory A [1]. Thereby, the process of step S35 is canceled and the control signal frame before executing it is restored.

In step S50, when the value of the memory A [0] holding the header data at the head of the received control signal frame is a predetermined value (SRP_response), the data length of the control signal frame is the correct length. Determine if there is. That is, when A [0] is SRP_response, it is checked whether or not the data length N of the control signal frame matches 4 bytes that is the correct data length. If they match, the process proceeds to step S51. If they do not match, the process proceeds to S40. In step S51, the presence or absence of a transmission error in this frame is checked using the error detection code FCS added to the received control signal frame. If no transmission error is found, the process proceeds to step S53 through step S52, and the partner terminal is recognized as a terminal (WNSRP terminal) compatible with the “WNSRP” protocol. If a transmission error is found, the process proceeds to step S40 and the received data of this frame is discarded.

  Note that a different value may be used as necessary for the constant (“0x5b” in steps S12, S14, S35, and S49) used by the error adding / removing unit 160 to add an error to the control signal frame. In order to remove the added error, it is necessary to use the same value on the transmission side and the reception side.

(Second Embodiment)
Another embodiment relating to the communication apparatus and the communication control method of the present invention will be described below with reference to FIGS.

  FIG. 9 is a sequence diagram illustrating a main operation of the communication apparatus and an example of a communication operation with another station in the second embodiment. FIG. 10 is a sequence diagram illustrating a main operation of the communication apparatus and an example of a communication operation with another station in the second embodiment. FIG. 11 is a schematic diagram illustrating a data configuration of a control signal handled by the communication device according to the second embodiment.

  This embodiment is a modification of the first embodiment, and assumes a case in which a terminal having the same configuration as that of the wireless communication terminal 100 shown in FIG. 2 is used as a communication apparatus for implementing the present invention. However, the operation of the wireless communication terminal 100 in the second embodiment is slightly different from that in the first embodiment. That is, the type of error added to the control signal frame transmitted by the error adding / removing unit 160 is changed.

  A configuration of a control signal frame handled by the wireless communication terminal 100 according to the second embodiment is shown in FIG. Here, since the modified SRP layer is assumed as a protocol, as shown in FIG. 11, the control signal frame 300A generated on the transmission side includes a header area 301 having a length of 1 octet and a sequence having a length of 1 octet. There are a number area 302, an information area 303 having an arbitrary length, and an FCS area 304 having a length of 2 octets.

  ID information indicating the type of control signal frame and the like is stored in the header area 301 of the control signal frame 300A, the sequence number of the control signal frame is stored in the sequence number area 302, and “H.245” is stored in the information area 303. Information such as a command defined in the above is stored, and a code necessary for checking the frame is stored in the FCS area 304.

  When operating in accordance with the SRP protocol, the entire control signal frame 300A is transmitted, but the error assignment / removal unit 160 of the second embodiment removes the header area 301 from the control signal frame 300A. A control signal frame 300B is generated, and the control signal frame 300B is transmitted.

  When the wireless communication terminal 100 according to the second embodiment receives the control signal frame 300B, the error addition / removal unit 160 on the receiving side adds the header area 301 to the control signal frame 300B and adds the control signal frame 300B. Restore 300A.

  That is, since the header region 301 does not exist in the control signal frame 300B transmitted from the wireless communication terminal 100, an error is surely generated when the receiving terminal operates according to the SRP protocol. However, the error addition / removal unit 160 adds the header region 301 in the terminal on the receiving side, so that the added error can be removed.

  In the operation example illustrated in FIG. 9, it is assumed that communication is performed between the wireless communication terminal 100A (WNSRP terminal) of the second embodiment and the wireless communication terminal 200 (existing terminal, that is, SRP terminal) operating according to the SRP protocol. is doing.

  In FIG. 9, the wireless communication terminal 100A generates control information including a command to be transmitted to the counterpart station in step S61, that is, the control signal frame 300A of FIG.

  In the next step S62, the error assignment / removal unit 160 on the wireless communication terminal 100A removes the header region 301 from the control signal frame 300A generated in step S61 and generates the control signal frame 300B. This control signal frame 300B is transmitted as a WNSRP frame (WNSRP Seq # 0) in step S63. When it is determined that the partner station is an SRP terminal, a normal SRP frame (SRP Seq # 0) is transmitted.

  On the other hand, since the wireless communication terminal 200 operates in accordance with the SRP protocol in FIG. 9, a normal SRP frame (SRP Seq # 0) is transmitted in step S71.

  When the wireless communication terminal 200 receives the control signal frame, the process proceeds to the next step S72, and the received frame is processed. Here, since there is no problem when the received frame is an SRP frame, the frame is processed as a command. However, if the received frame is a WNSRP frame, an error is detected because the header area 301 does not exist, and this frame is discarded.

  When the wireless communication terminal 200 receives the SRP frame, the SRP frame (SRP Res Seq # 0) is transmitted as a response in the next step S73.

  On the other hand, when receiving the control signal frame from the counterpart station, the radio communication terminal 100A proceeds to step S64 and inspects the received control signal frame. When the SRP frame is received from the wireless communication terminal 200, there is no problem in the contents of the frame, so the process proceeds from step S64 to step S65, and a response SRP frame (SRP Res Seq # 0) is generated and transmitted. . In addition, the process after step S66 is needed when communicating between WNSRP terminals.

  In the operation example illustrated in FIG. 10, it is assumed that communication is performed between the wireless communication terminal 100A and the wireless communication terminal 100B, that is, a case where the wireless communication terminals 100 (WNSRP terminals) of the second embodiment communicate with each other. Yes. Since the wireless communication terminal 100A shown in FIG. 9 and the wireless communication terminal 100A shown in FIG. 10 basically perform the same operation, the corresponding steps are indicated by the same step numbers.

  The radio communication terminal 100B shown in FIG. 10 has the same function as the radio communication terminal 100A, but in FIG. 10, the radio communication terminal 100B initially operates according to the SRP protocol.

  When receiving the control signal frame from the partner station, the wireless communication terminal 100B identifies whether the type of the received control signal frame is a WNSRP frame in step S82. That is, it is determined whether the control signal frame is an SRP frame or a WNSRP frame by checking whether or not the SRP frame header is present at the head position of the received control signal frame.

  When it is detected that the WNSRP frame has been received, the process proceeds from step S82 to step S83, and its own operation mode is switched so that the wireless communication terminal 100B operates according to the new protocol (WNSRP protocol).

  In step S84, when the wireless communication terminal 100B is operating according to the WNSRP protocol, a response is transmitted using the WNSRP frame, and when the wireless communication terminal 100B is operating according to the SRP protocol, a response is transmitted using the SRP frame.

  When the wireless communication terminal 100B transmits a WNSRP frame, since no header is included in this frame, an error is detected in step S64 of the wireless communication terminal 100A. As a result, the processing of the wireless communication terminal 100A is performed in step S66. Proceed to

  In step S66, a WNSRP header (contents of the header area 301 in FIG. 11: 0xF1) prepared in advance is added to the received frame, and then the frame is checked again. When the wireless communication terminal 100A receives the WNSRP frame from the wireless communication terminal 100B, the original control signal frame (300A in FIG. 11) is restored by adding a header to the head of the received frame, so that an error occurs. Is removed and the inspection succeeds. In that case, the wireless communication terminal 100B transmits a response of the WNSRP frame in the next step S67.

  In any case, when a WNSRP frame corresponding to the new protocol is transmitted from the wireless communication terminal 100A corresponding to the new protocol, the existing terminal (200) reliably discards the WNSRP frame as an error, so that an abnormal operation occurs. Absent.

  As for the control signal frame for response, the WNSRP frame and the SRP frame can be distinguished on the receiving side by the difference in the data length (number of bytes) of the received frame.

  As described above, by applying the present invention to a mobile phone terminal of a third generation mobile communication system or a communication device that communicates with such a terminal, an existing protocol that supports only an existing protocol can be used. Even when a terminal and a new terminal corresponding to a new protocol positioned above the existing protocol are mixed on the same communication network, abnormal operation can be prevented, and between the existing terminal and the new terminal can be prevented. It is also possible to communicate with each other. Therefore, in addition to the protocol defined in the standard, a newly developed control signal retransmission protocol can be used, and the problems in the existing standard can be solved.

It is a sequence diagram showing the main operation | movement of the communication apparatus in 1st Embodiment, and the communication operation example between other stations. It is a block diagram which shows the structural example of a communication apparatus. It is a flowchart which shows the detailed operation | movement at the time of reception of the communication apparatus in 1st Embodiment. It is a sequence diagram showing the example of a communication operation between the communication apparatus and other station in 1st Embodiment. It is a sequence diagram showing the example of a communication operation between the communication apparatus and other station in 1st Embodiment. It is a sequence diagram showing the communication operation example between the other stations which have the same function as the communication apparatus in 1st Embodiment. It is a sequence diagram showing the communication operation example between the other stations which have the same function as the communication apparatus in 1st Embodiment. It is a schematic diagram which shows the data structure of the control signal which the communication apparatus in 1st Embodiment handles. It is a sequence diagram showing main operation | movement of the communication apparatus in 2nd Embodiment, and the communication operation example between other stations. It is a sequence diagram showing main operation | movement of the communication apparatus in 2nd Embodiment, and the communication operation example between other stations. It is a schematic diagram which shows the data structure of the control signal which the communication apparatus in 2nd Embodiment handles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Function information 20 Control signal frame 20B Changed control signal frame 100 Wireless communication terminal 110 Wireless unit 120 Multiplexing unit 130 Video coding / decoding unit 140 Voice coding / decoding unit 150 Control signal generating unit 160 Error adding / removing unit 170 Control unit 200 Wireless communication terminal 300A, 300B Control signal frame 301 Header area 302 Sequence number area 303 Information area 304 FCS area

Claims (7)

A communication device that communicates between a plurality of communication stations according to a protocol defined in advance,
Regarding a control signal transmission protocol for communication, a control unit is provided that performs control according to a second standard that is positioned above the first standard defined in advance, and the control unit controls the control signal according to the second standard. Is transmitted, a first signal outside the standard of the first standard is generated so that the receiving unit of the counterpart terminal operating according to the first standard generates an error, and the first standard is generated. When a control signal is received from a counterpart terminal operating according to the above, a second signal outside the first standard is generated as a response signal so that the receiver of the counterpart terminal generates an error. A communication device characterized by the above.   2. The communication device according to claim 1, wherein the control unit includes the first signal and the second signal so that a receiving unit of a counterpart terminal operating according to the first standard generates an error of a predetermined fixed pattern. A communication device characterized by generating a signal.   3. The communication device according to claim 2, wherein the control unit outputs a result obtained by performing a logical operation on data in a specific area of a predetermined control signal frame and a predetermined constant as the first signal or the second signal. A communication device. A communication device that communicates between a plurality of communication stations according to a protocol defined in advance,
Regarding a control signal transmission protocol for communication, a control unit is provided that performs control according to a second standard that is positioned above the first standard defined in advance, and the control unit controls the control signal according to the second standard. Is transmitted, the information lacking at least a part of the information required by the first standard is deleted so that the receiving unit of the counterpart terminal operating according to the first standard generates an error. A communication apparatus, characterized in that the first signal is generated as a first signal outside the standard of one standard.   5. The communication apparatus according to claim 1, wherein a video processing unit that encodes / decodes video information, an audio processing unit that encodes / decodes audio information, and a video processing unit. And a wireless communication unit for transmitting and receiving a signal obtained by multiplexing the signal of the voice processing unit and the signal of the audio processing unit as a wireless signal. A communication control method for communicating between a plurality of communication stations according to a protocol defined in advance in a standard,
When the control unit that controls the control signal transmission protocol for communication of each communication station performs control in accordance with the second standard located above the first standard defined in advance,
When transmitting a control signal from the local station to the counterpart terminal in accordance with the second standard, the receiver of the counterpart terminal operating in accordance with the first standard is out of the standard of the first standard so that an error occurs. The communication control method characterized by producing | generating the 1st signal of. The communication control method according to claim 6,
When the control unit that controls the control signal transmission protocol for communication of each communication station performs control in accordance with the second standard located above the first standard defined in advance,
When receiving a control signal from a counterpart terminal operating in accordance with the first standard, a response is made to a second signal outside the standard of the first standard so that the receiver of the counterpart terminal generates an error. A communication control method characterized by generating as a signal.

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