JP2011188509A - Radio transmitter and radio transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that instantaneous interruption of transmission data may be generated in the process of switching a modulation mode in a present radio transmission method used in a radio transmitter. <P>SOLUTION: In the radio transmission method, the radio transmitter identifies and monitors the state of communication environment for each system by monitoring communication environment of radio transmission paths of a current system and a preliminary system; selects modulation/demodulation systems based on identification result for each of the systems; generates a switching signal for switching the current system and the preliminary system, based on the identification result for each system; and switches the current system and the preliminary system, based on the switching signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless transmission apparatus and a wireless transmission method for transmitting a data string signal using a plurality of systems.

  This type of wireless transmission device is described in Patent Document 1, for example.

  FIG. 4 is a block diagram showing the wireless transmission system of Patent Document 1. As shown in FIG.

  The wireless transmission system described in Patent Document 1 performs data transmission between the wireless transmission device D1 and the wireless transmission device D2. The wireless transmission device D1 includes a transceiver D3, a modulation circuit D5, a demodulation circuit D7, a modulator control circuit D11, and an interface circuit D9. The wireless transmission device D2 includes a transceiver D4, a modulation circuit D6, a demodulation circuit D8, a modulation system control circuit D12, a delay circuit D13, and an interface circuit D10.

  The demodulation circuit D8 of the wireless transmission device D2 outputs a line quality signal d101 to the modulation scheme control circuit D12 when the wireless line quality of the wireless transmission path changes. The modulation system control circuit D12 determines the modulation system based on the channel quality signal d101, and transmits the modulation system instruction signal d102 from the modulation circuit D6 to the demodulation circuit D7 of the opposite radio transmission apparatus D1 via the transceiver D4.

  The demodulation circuit D7 of the wireless transmission device D1 transmits the modulation method instruction signal d104 to the modulator control circuit D11, and switches the modulation method in the modulation circuit D5 based on the modulator control signal d105. Further, the delay circuit D13 delays the demodulator control signal d103 to the demodulation circuit D8 until the modulation system switching of the modulation circuit D5 is completed by the modulator control signal d105.

  That is, Patent Document 1 describes a wireless transmission device that monitors the line quality of a wireless transmission path, switches a modulation system in a timely manner, and transmits data using a modulation system according to the line state of the wireless transmission path. If this technology is used, transmission can be performed with a modulation scheme according to the line state of the wireless transmission path, and a limited transmission path band can be used effectively.

JP 2005-223835 A

  However, even in the wireless transmission system described in Patent Document 1, it can be found that instantaneous interruption of transmission data occurs in the process of switching the modulation method. This is because the timing for switching the modulation method on the transmission side does not necessarily match the timing for switching the modulation method on the reception side.

  An object of the present invention is to provide a wireless transmission apparatus that solves the above-described problems and eliminates transmission data loss in a process of switching a modulation scheme in accordance with the transmission path state of the wireless transmission path.

  A wireless transmission device according to the present invention monitors a communication environment of a wireless transmission path of the working system and the standby system in a wireless transmission device having a working system and a standby system that transmits a data string signal using wireless communication. The monitoring means for identifying the state of the communication environment for each system, the modulation / demodulation method selecting means for selecting the modulation / demodulation method using the identification result for each system of the monitoring means, and the identification result for each system of the monitoring means And a switching signal generating means for generating a switching signal for switching between the working system and the standby system.

  The wireless transmission device according to the present invention includes a first pulse train serving as a reference signal in the wireless transmission device having a working system and a standby system for transmitting a data train signal using wireless communication, and the first pulse train. A reference signal generating circuit for generating a second pulse train having a smaller repetition frequency, and multiplexing a data train signal to be transmitted in synchronization with the first pulse train as a frame multiplexed signal of the working system and the standby system, The frame multiplexed signals of the working system and the standby system may be synchronized with the second pulse train.

  ADVANTAGE OF THE INVENTION According to this invention, the wireless transmission apparatus which eliminates the loss of the transmission data in the process which switches a modulation system according to the transmission-line state of a wireless transmission path can be provided.

1 is a block diagram illustrating a wireless transmission system according to an embodiment. It is a timing chart used for operation | movement description of this Embodiment. It is a timing chart which illustrates the synchronous timing of each modulation system. 1 is a block diagram showing a wireless transmission system of Patent Document 1. FIG.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram illustrating a wireless transmission system according to an embodiment. In FIG. 1, a wireless transmission device A100 and a wireless transmission device B200 are the same device. In the description of the present embodiment, the wireless transmission device A100 is a PDH (Plesiochronous Digital Hierachy) signal transmission side (input side), and the wireless transmission device B200 is a reception side (output side). The configuration of the transmission system and the like will be described with the wireless transmission device A100, and the reception system will be described with the wireless transmission device B200.

  The wireless transmission device A100 includes a reference frame generation circuit A1, a stuff circuit A2, an active frame multiplexing circuit A3, a standby frame multiplexing circuit A4, an active modulation circuit A5, and a standby modulation circuit A6 as transmission circuits.

  The reference frame generation circuit A1 (reference signal generation circuit) is configured to generate a reference clock (first pulse train) and a reference frame pulse a002 (second output), which are generation references for a working radio frame multiplexed signal a004 and a backup radio frame multiplexed signal a005, which will be described later. Pulse train) is generated and output to the stuff circuit A2, the active system frame multiplexing circuit A3 and the standby system frame multiplexing circuit A4.

  The stuff circuit A2 performs stuff synchronization processing on n (n is a natural number) received PDH data string signals a001 inputted from the outside with respect to the reference clock and the reference frame pulse a002, and n stuff synchronization data strings a003. Are output to the active frame multiplexing circuit A3 and the standby frame multiplexing circuit A4.

  The active frame multiplex circuit A3 has n stuff synchronizations input from the stuff circuit A2 in accordance with the reference clock, the reference frame pulse a002, and the active modulation scheme control signal a016 transmitted by the active frame synchronization circuit A10 which is a transmission system circuit. The data string a003 and the modulation scheme control information are multiplexed according to the modulation scheme and output as a working radio frame multiplexed signal a004.

  The working modulation circuit A5 modulates the working radio frame multiplexed signal a004 input from the working frame multiplexing circuit A3 by using the modulation method indicated by the working modulation method control signal a016, and the working radio transmission signal a006 is sent to the wireless transmission path C30.

  The spare frame multiplex circuit A4 has n stuff synchronizations input from the stuff circuit A2 in accordance with the reference clock, the reference frame pulse a002, and the spare modulation scheme control signal a017 transmitted by the spare frame synchronization circuit A11 which is a transmission circuit. The data string a003 and the modulation scheme control information are multiplexed according to the modulation scheme and output as a spare radio frame multiplexed signal a005. The frame period of the radio frame multiplexed signal uses the same period for both the active system and the standby system.

  The backup modulation circuit A6 modulates the backup radio frame multiplexed signal a005 input from the backup frame multiplexing circuit A4 using the modulation scheme indicated by the backup modulation scheme control signal a017, and performs backup radio transmission signal. a007 is sent to the wireless transmission path C31.

  The radio transmission apparatus A100 includes a reception monitoring circuit A7, an active demodulation circuit A8, a standby demodulation circuit A9, an active frame synchronization circuit A10, a standby frame synchronization circuit A11, an uninterruptible switching circuit A12, and a reception system circuit. It has a stuff circuit A13. Since the reception system circuit of the wireless transmission device A100 has the same configuration as the reception system circuit of the wireless transmission device B200, which will be described later, description thereof is omitted in the description of the wireless transmission device B200.

  The radio transmission apparatus B200 includes a reference frame generation circuit B1, a stuff circuit B2, an active frame multiplexing circuit B3, a standby frame multiplexing circuit B4, an active modulation circuit B5, and a standby modulation circuit B6 as transmission circuits. Since the transmission system circuit of the wireless transmission device B200 has the same configuration as the transmission system circuit of the wireless transmission device A100, the description thereof is omitted.

  The radio transmission apparatus B200 includes a reception monitoring circuit B7, an active demodulation circuit B8, a standby demodulation circuit B9, an active frame synchronization circuit B10, a standby frame synchronization circuit B11, an uninterruptible switching circuit B12, and a reception system circuit. It has a stuff circuit B13.

  The working demodulation circuit B8 measures the reception level of the working radio reception signal b008 input from the radio transmission apparatus A100 via the radio transmission path C30, and outputs the working reception level monitor signal b011 to the reception monitoring circuit B7. Similarly, the current demodulation method is switched according to the current demodulation method control signal b012 input from the reception monitoring circuit B7, and the current demodulation signal b010 is output to the current frame synchronization circuit B10.

  The working frame synchronization circuit B10 detects the radio frame synchronization of the working demodulated signal b010 and outputs the working radio frame data string b019 to the uninterruptible switching circuit B12. Also, the working frame synchronization circuit B10 extracts the modulation scheme control information multiplexed on the working radio frame multiplexed signal a004 by the working frame multiplexing circuit A3 of the radio transmission apparatus A100, and uses the working modulation scheme control signal b016 as the working frame. The data is output to the multiplexing circuit B3 and the working modulation circuit B5.

  Since the standby demodulation circuit B9 and the standby frame synchronization circuit B11 have the same structure as the active demodulation circuit B8 and the active frame synchronization circuit B10, description thereof is omitted.

  The reception monitoring circuit B7 discriminates the line states of the radio transmission path C30 and the radio transmission path C31 from the current reception monitor signal b011 and the standby reception monitor signal b014, and the current demodulation system control signal b012 is used as the current demodulation circuit B8 and the current system frame. The spare demodulation system control signal b015 is output to the multiplexer B3 to the spare demodulator B9 and the spare frame multiplexer B4. The reception monitoring circuit B7 outputs a switching control signal a018 to the uninterruptible switching circuit B12.

  The uninterruptible switching circuit B12 includes a memory for aligning the phase difference between input frames, switches the line between the active radio frame data string b019 and the backup radio frame data string b020 in accordance with the switching control signal b018, and after switching The radio frame data is output to the destuff circuit B13 as a radio frame data string b021.

  The destuffing circuit B13 extracts the transmission PDH data string signal b022 from the radio frame data string b021 by the destuffing process and outputs it to the outside.

  With such a configuration, the wireless transmission system according to the present embodiment can reduce transmission data loss in the process of switching the modulation scheme according to the transmission path state of the wireless transmission path.

  Next, the operation of the wireless transmission system will be described with reference to FIGS.

  In this description of operation, if four (n = 4) received PDH data string signals a001 are input from the outside and the modulation method is QPSK (Quadrature Phase Shift Keying), two of the four received PDH data string signals are included. In the following description, it is assumed that all the received PDH data string signals are transmitted, and if four QPDs (Quadrature Amplitude Modulation) are transmitted, all four received PDH data string signals are transmitted. In the configuration of this wireless transmission system, the symbol frequency in each modulation method is the same frequency. Therefore, the radio transmission capacity in 16QAM is twice the radio transmission capacity in QPSK.

  Also, the working radio frame multiplexed signal a004 and the backup radio frame multiplexed signal a005, which are radio frame multiplexed signals described in the description of the operation, are composed of an overhead area and a payload area as shown in the timing chart of FIG.

  FIG. 2 is a timing chart used for explaining the operation of this embodiment.

  The radio frame multiplexed signal is synchronized with the frequency of the reference clock and the reference frame pulse, and the synchronization timing is the same regardless of the modulation method.

  In the overhead area of the radio frame multiplexed signal, a frame bit for establishing frame synchronization and an alarm transfer bit to the opposite station are assigned. In the payload area, two of the four stuff synchronization data sequences in the case of QPSK and all four stuff synchronization data sequences in the case of 16QAM are time-division multiplexed in accordance with the phase of the reference frame pulse.

  The wireless transmission system including the wireless transmission device A100 and the wireless transmission device B200 operates as follows using a synchronized wireless frame multiplexed signal regardless of the modulation method. For the sake of clarity, the detailed operation of each part is omitted.

  The reference frame generation circuit A1 of the wireless transmission device A100 generates a reference clock and a reference frame pulse a002 that serve as a reference for the working radio frame multiplexed signal a004 and the standby radio frame multiplexed signal a005, and the stuff circuit A2 and working system frame multiplexing circuit A3. And output to the standby frame multiplexing circuit A4.

  The stuff circuit A2 stuffs four received PDH data string signals a001 inputted from the outside with respect to a reference clock, and stuffs the four stuff synchronization data strings a003 after stuff processing into the working frame multiplexing circuit A3 and Output to the spare frame multiplexing circuit A4.

  The working radio frame multiplexing circuit A3 generates a stuff synchronization data string a003 as a working radio frame multiplexed signal a004 according to the reference clock and the reference frame pulse a002. The modulation scheme is specified by a modulation scheme control signal described later.

  The working modulation circuit A5 modulates the working radio frame multiplexed signal a004 to the working radio frame multiplexed signal a004 by a modulation method designated by a working modulation method control signal a016 described later, and sends the working radio signal a006 to the radio transmission line C30.

  Since the operations of the standby radio frame multiplexing circuit A4 and the standby modulation circuit A6 are the same as those of the active frame multiplexing circuit A3 and the active modulation circuit A5, the description thereof is omitted.

  The radio transmission paths C30 and C31 propagate the active and standby radio signals. The wireless transmission path has a temporal and spatial influence on the wireless signal due to the influence of fading or the like.

  The working demodulation circuit B8 of the wireless transmission device B200 receives the working radio reception signal b008 via the transmission line C30, monitors the reception level, and outputs the working reception level monitor signal b011 to the reception monitoring circuit B7.

  The reception monitoring circuit B7 uses the working reception level monitor signal b011 to identify the working modulation system, determines the demodulation system, and outputs it to the working demodulation circuit B8 as the working demodulation system control signal b012.

  The working demodulation circuit B8 identifies the working demodulation system control signal b012, demodulates the working radio reception signal b008 according to the working demodulation method determined by the reception monitoring circuit B7, and uses the working demodulation signal b010 as the working frame synchronization circuit. Output to B10.

  The working frame synchronization circuit B10 detects the radio frame synchronization of the working demodulated signal b010, establishes frame synchronization, and outputs the working radio frame data string b019 to the uninterruptible switching circuit B12. At the same time, the working frame synchronization circuit B10 extracts the modulation scheme control information multiplexed on the working radio frame multiplexed signal a004 by the working frame multiplexing circuit A3 of the radio transmission apparatus A100, and uses the working modulation scheme control signal b016. The data is output to the system frame multiplexing circuit B3 and the working system modulation circuit B5.

  Since the operations of the standby demodulation circuit B9 and the standby frame synchronization circuit B11 are the same as those of the current demodulation circuit B8 and the current frame synchronization circuit B10, description thereof will be omitted.

  The uninterruptible switching circuit B12 receives the working radio frame data sequence b019 and the backup radio frame data sequence b020, and aligns both radio frame data sequences at the same timing using a built-in memory. Further, the uninterruptible switching circuit B12 selects one of the current radio frame data sequence b019 and the backup radio frame data sequence b020 in accordance with the switching control signal b018 input from the reception monitoring circuit B7, and destuffs it as the radio frame data sequence b021. Output to circuit B13.

  The destuff circuit B13 extracts two or four stuff synchronization data sequences from the radio frame data sequence b021 in accordance with the selected active or standby modulation / demodulation method, performs destuffing processing, and performs two or four stuffing data sequences. The transmission PDH data string signal b201 is output to the outside. When the modulation / demodulation method is QPSK, two PDH data string signals are transmitted, and when it is 16 QAM, four PDH data string signals are transmitted.

  Next, the switching operation of the modulation system and the switching operation (selection operation) of the uninterruptible switching circuit B12 will be described in detail. Note that the threshold of the reception level for switching between the active system and the standby system and switching of each modulation method is T1.

  The reception monitoring circuit B7 monitors the reception levels of the wireless transmission path C30 and the wireless transmission path C31 and determines whether the reception level is good (communication environment is good). The reception monitoring circuit B7 selects an appropriate modulation method from both the active and standby communication environments, notifies the active demodulation circuit B8 and the standby demodulation circuit B9 of the selected appropriate modulation method, The selection result is notified to the instantaneous interruption switching circuit B12. Further, when the communication environment of the standby system is better than that of the active system, the instantaneous interruption switching circuit B12 is notified of the use of the standby system by using the switching control signal b018. Furthermore, the selected modulation scheme is notified to the working frame multiplexing circuit B3 and the standby frame multiplexing circuit B4.

  Specifically, the reception monitoring circuit B7 identifies the communication environment of the wireless transmission paths C30 and C31 using the current reception level monitor signal b011 and the standby reception level monitor signal b014, and if the reception environment is higher than the threshold value T1, 16QAM modulation is performed. QPSK is selected when it is lower than the threshold value T1, the selection result is notified to the active demodulation circuit B8 using the active demodulation control signal b012, and the standby demodulation control signal is sent to the standby demodulation circuit B9. Notification is made using b015. Simultaneously, the uninterruptible switching circuit B12 is notified of a selection result of a system having a good communication state as a switching control signal b018. Furthermore, the selected modulation scheme is notified to the working frame multiplexing circuit B3 and the standby frame multiplexing circuit B4.

  The working demodulation circuit B8 demodulates the received working radio reception signal b008 in accordance with the modulation / demodulation method notified from the reception monitoring circuit B7, and outputs it to the working frame synchronization circuit B10 as the working demodulation signal b010.

  The standby demodulation circuit B9 demodulates the received standby radio reception signal b009 according to the modulation / demodulation method notified from the reception monitoring circuit B7, and outputs it to the backup frame synchronization circuit B11 as the backup demodulation signal b013.

  The working frame synchronization circuit B10 detects the synchronization of the working demodulated signal b010, outputs the working radio frame data string b019 to the uninterruptible switching circuit B12, and also modulates the modulation scheme control information multiplexed on the working demodulated signal b010. And is output to the working frame multiplexing circuit B3 and the working modulation circuit B5 as the working modulation system control signal b016.

  The spare frame synchronization circuit B11 detects the synchronization of the spare demodulated signal b013, outputs the spare radio frame data string b020 to the uninterruptible switching circuit B12, and also modulates the modulation scheme control information multiplexed on the spare demodulated signal b013. And is output to the backup frame multiplexing circuit B4 and the backup modulation circuit B6 as the current modulation scheme control signal b017.

  The uninterruptible switching circuit B12 aligns the phase differences between the active radio frame data sequence b019 and the backup radio frame data sequence b020, and, according to the switching control signal b018, the active radio frame data sequence b019 and the backup radio frame data sequence b020. And the switched radio frame data are output to the destuff circuit B13 as a radio frame data string b021.

  Here, by aligning the phase difference between frames of the active radio frame data sequence b019 and the backup radio frame data sequence b020, when switching to the system or the like indicated by the switching control signal b018, instantaneous interruption caused by the phase difference is prevented. Can be prevented.

  On the other hand, the working frame multiplexing circuit B3 multiplexes the modulation / demodulation method notified from the reception monitoring circuit B7 into the working radio frame multiplexed signal b004 as modulation method control information.

  The backup frame multiplexing circuit B4 multiplexes the modulation / demodulation method notified from the reception monitoring circuit B7 as modulation method control information to the generated standby radio frame multiplexed signal b005.

  The radio frame multiplexed signals (b004, b005) on which the modulation system control information of each system is multiplexed are modulated by the active modulation circuit B5 and the standby modulation circuit B6, and pass through the radio transmission paths (C30, C31). And transmitted to the wireless transmission device A100.

  The demodulation circuits (A8, A9) of the wireless transmission device A100 receive the radio reception signals (a008, a009) multiplexed with the modulation system control information of the respective systems, demodulate them, and use them as demodulated signals (a010, a013). The frame synchronization circuit (A10, A11) is notified.

  The frame synchronization circuit (A10, A11) acquires modulation scheme information used in each system of the wireless transmission device A100 from the demodulated signal (a010, a013), outputs a modulation scheme control signal (a016, a017), and wirelessly The modulation / demodulation method of each system used for wireless communication from the transmission apparatus A100 to the wireless transmission apparatus B200 is designated.

  By operating in this way, switching of the system can be switched without instantaneous interruption, and further, each modulation method can be switched after the instantaneous switching is performed.

  That is, the received signals of the active system and the standby system received via the wireless transmission path are synchronized using the reference clock pulse, respectively, and the received signals of the active system and the standby system are processed using the reference clock pulse, respectively. Modulation method according to the transmission path state of the wireless transmission path by enabling the system to be switched between the received signal of the active system and the standby system that is synchronized using the reference frame pulse and synchronized using the reference frame pulse. It is possible to prevent loss of transmission data that occurs due to asynchronous or loss of synchronization at the time of switching.

  Specifically, there is an effect that a plurality of PDH data string signals transmitted between wireless transmission apparatuses are not lost when switching between wireless modulation systems. This is because the modulation system is switched separately for the radio transmission path of the selection system (working system) and the non-selection system (standby system), and the frame period (symbol period) of the radio frame data string is set for each modulation system. This is because the data period of the stuff synchronization data sequence after the stuff process multiplexed in the payload area is set to the same phase.

  Further, since the timely processing is performed, the data delay amount can be suppressed. This is because, even if the type of modulation system is changed on the transmission side, the PDH data string signal after the stuffing process in which the frame start positions of the active and standby radio frame multiplexed signals are made the same and multiplexed in the payload area This is because the modulation system is switched using a memory that aligns the start positions of the data phases (symbol periods) of the data and absorbs the transmission delay difference between the active transmission line and the standby transmission line on the receiving side.

  Note that it is desirable to prioritize the system that is not currently selected for switching between the active and standby modulation methods.

  As an example of an operation that gives priority to a system that is not currently selected, when the transmission path state of the standby radio transmission path C31, which is a 16QAM transmission system, is changed to QPSK after the active modulation / demodulation system is changed to QPSK, The uninterruptible switching circuit B12 switches from the standby radio frame data string b019 to the working radio frame data string b020.

  The standby system has a 16QAM transmission method, and transmits four transmission PDH data string signals while the reference clock is four clocks. The active system transmits two PDH data string signals by the QPSK transmission method. Is transmitting. As shown in the timing chart of FIG. 2, the two stuff synchronization data strings CH1 and CH2 after the stuff process are assigned to the same phase in synchronization with the reference frame pulse, and even in different transmission paths and different modulation schemes, There is no phase difference between the generated frames. This is an effect of the memory that aligns the phase differences of the uninterruptible switching circuit B12. In addition, since there is no phase difference between frames, it is possible to switch between the active system and the standby system without interruption.

  After the radio frame data sequence is switched, the working modulation system is changed from 16QAM to QPSK by the same operation as the working system, so that both the working system and the working system become the QPSK modulation system.

  When the reception level of the transmission path is improved, the modulation system of the system that has not been selected is switched from QPSK to 16QAM, and then the selection system is switched in the uninterruptible switching circuit B12. As a result, the number of transmissions of the PDH data string signal is increased from two to four, and the two PDH data string signals passed through the QPSK modulation method can be transmitted without being interrupted.

  In the above embodiment, a radio transmission apparatus that switches between 16QAM and QPSK modulation schemes has been described. However, the present invention is also applicable to multi-level modulation schemes of 32QAM or higher.

  Further, even when switching between three or more types of modulation schemes, the modulation schemes can be switched without instantaneously interrupting a certain number of PDH data string signals.

  FIG. 3 is a timing chart illustrating the synchronization timing of each modulation method.

  If the symbol frequency (symbol period) is constant for each modulation scheme, 16QAM has a transmission capacity twice that of QPSK. Similarly, the transmission capacity of 32QAM is 2.5 times that of QPSK, 64QAM is 3 times, 128QAM is 3.5 times, and 256QAM is 4 times the transmission capacity.

  When the modulation method is QPSK and a frame multiplexed signal for transmitting two PDH data string signals is generated (illustrated in FIG. 3), four 16QAM, five 32QAM, six 64QAM, seven 128QAM, 256QAM can assign eight PDH data string signals.

  As described above, when the modulation schemes of the active system and the standby system are different, by assigning the stuff synchronization data string after the stuff processing to the same phase with respect to the reference frame pulse, the active system transmission line and the standby system transmission line Match the frame phase. By matching the frame phases of the active transmission line and the standby transmission line, it is possible to prevent instantaneous interruption of the PDH data string signal by switching between the active system and the standby system.

  In this way, the continuity of each stuff synchronization data sequence multiplexed in the frame data sequence at the time of system switching is ensured.

  Further, by ensuring the continuity of each stuff synchronization data string by not selecting the system that is executing the modulation system switching control, the instantaneous interruption of the PDH data string transmission that occurs at the time of switching between the active system and the standby system and at the time of switching the modulation system prevent.

  In the above-described embodiment, the active system is one system and the standby system is one system. However, the active system and the standby system are not necessarily limited to one system. The active system may be a plurality of systems and the standby system may be a single system, or the active system may be a plurality of systems and the standby system may be a plurality of systems. Also at this time, by performing the same configuration and operation, it is possible to prevent instantaneous interruption at the time of system switching.

100 Wireless transmission device A
200 Wireless transmission device B
A1, B1 Reference frame generation circuit A2, B2 Stuff circuit A3, B3 Active frame multiplexing circuit A4, B4 Standby frame multiplexing circuit A5, B5 Active modulation circuit A6, B6 Standby modulation circuit A7, B7 Reception monitoring circuit A8, B8 Active demodulation circuit A9, B9 Standby demodulation circuit A10, B10 Active frame synchronization circuit A11, B11 Standby frame synchronization circuit A12, B12 Uninterruptible switching circuit A13, B13 Destuff circuit C30, C31 Wireless transmission path

Claims (11)

A wireless transmission method for transmitting a data string signal by switching a system used in a wireless transmission device having an active system and a standby system,
The wireless transmission device is:
Monitor the communication environment of the wireless transmission path of the working system and the standby system to identify and monitor the state of the communication environment for each system,
Based on the identification result for each system by the monitoring, select a modulation / demodulation method,
Based on the identification result for each system by the monitoring, to generate a switching signal for switching the working system and the standby system,
A wireless transmission method characterized in that a working system and a standby system are switched based on the switching signal. The wireless transmission method according to claim 1,
The modulation / demodulation method selected in each of the working system and the backup system is transmitted to the opposing wireless transmission device,
A radio transmission method characterized in that the opposite radio transmission apparatus performs modulation according to a selected modulation / demodulation method to set the modulation / demodulation method of each data string signal of the working system and the backup system. The wireless transmission method according to claim 1 or 2,
For each of the working system and the standby system, the start bit of the demodulated received signal sequence is synchronized with the reference frame,
A wireless transmission method characterized by performing a process of aligning the phase difference between the signal trains of the signal train of the active system and the signal train of the standby system that have been subjected to the synchronization process. In a wireless transmission device having a working system and a standby system for transmitting a data string signal using wireless communication,
Monitoring means for monitoring the communication environment of the wireless transmission path of the working system and the standby system and identifying the state of the communication environment for each system;
Modulation / demodulation method selection means for selecting a modulation / demodulation method using the identification result for each system of the monitoring means,
A radio transmission apparatus comprising: a switching signal generating unit configured to generate a switching signal for switching between the active system and the standby system using the identification result of each system of the monitoring unit. The wireless transmission device according to claim 4,
A wireless transmission device comprising means for transmitting the modulation / demodulation method selected by the modulation / demodulation method selection means to an opposing wireless transmission device. The wireless transmission device according to claim 4 or 5,
Demodulating means for performing demodulation using the selection result of the modulation / demodulation system from the modulation / demodulation system selection means for each of the working system and the standby system;
Synchronizing means for synchronizing the start bit of the signal sequence demodulated by the demodulating means with a reference frame for each of the working system and the standby system,
A wireless transmission apparatus comprising: means for equalizing a phase difference between the signal trains of the active system signal train and the standby system signal train, synchronized by the synchronization means. The wireless transmission device according to any one of claims 4 to 6,
A radio transmission apparatus, wherein a modulation scheme suitable for a communication environment state is selected from modulation schemes having the same symbol frequency in accordance with a communication environment state for each system monitored by the monitoring means. The wireless transmission device according to any one of claims 4 to 7,
A radio transmission apparatus characterized in that a signal sequence transmitted through the radio transmission apparatus is a PDH (Plesiochronous Digital Hierachy) signal. A wireless transmission device according to any one of claims 4 to 8,
The modulation / demodulation method selection means can select three or more modulation / demodulation methods. The wireless transmission device according to any one of claims 4 to 9,
A wireless transmission apparatus characterized in that a modulation / demodulation method used between wireless transmission apparatuses is any one or a combination of 256 QAM (Quadrature Amplitude Modulation), 128 QAM, 64 QAM, 32 QAM, 16 QAM, and QPSK (Quadrature Phase Shift Keying). The wireless transmission device according to any one of claims 4 to 10,
A wireless transmission apparatus having a configuration in which one or both of an active system and a standby system are formed into a plurality of lines.

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