JP2007124474A - Wireless entrance system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless entrance system wherein a receiver side wireless communication apparatus absorbs an offset of a transmission signal caused when an active system transmitter side wireless communication apparatus is switched into a standby system transmitter side wireless communication apparatus. <P>SOLUTION: When detecting a switching prediction signal from a first wireless frame before the switching, a switching prediction signal detection means 184 holds an AGC circuit 170 and a carrier recovery circuit 174 and informs an estimate signal reception circuit 178 about a timing when the circuit 178 acquires an estimate signal. The estimate signal reception circuit 178 acquires the estimate signal from a second wireless frame after the switching on the basis of the timing to provide an output of the estimate signal to a phase difference estimate circuit 180 and a gain difference estimate circuit 182. The phase difference estimate circuit 180 estimates a phase offset of the wireless frames before and after the switching, and the gain difference estimate circuit 182 estimates a gain offset of the wireless frames before and after the switching. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless entrance system that transmits a transmission signal from a transmitting-side wireless communication device to a receiving-side wireless communication device via a wireless line, and at the time of switching from an active device to a standby device in the transmitting-side wireless communication device The present invention relates to a wireless entrance system that absorbs the generated impact on the receiving side with the receiving-side wireless communication device.

  Conventionally, in a wireless entrance system in which wireless communication devices are arranged on a transmission side and a reception side, the transmission side wireless communication device has a redundant configuration including two devices, an active device and a standby device. A highly reliable system is realized in which a line is not disconnected when switching from the active system device to the standby system device required for maintenance of the wireless communication device.

  In this case, the reception-side wireless communication device has a redundant configuration in which an active device and a standby device are arranged in the same manner as the transmission-side wireless communication device. Therefore, the switching is performed on either the transmission side or the reception side. However, in this specification, switching on the transmission side will be described.

  In Patent Document 1, when a transmission signal is transmitted from a transmission-side wireless communication device to a reception-side wireless communication device via a wireless line, it occurs at the time of switching from the active device to the standby device in the transmission-side wireless communication device. In order to absorb the impact on the receiving side such as deterioration of the bit error rate (so-called phase gap or local phase jump) by the receiving side wireless communication device, the receiving side wireless communication device is configured as shown in FIG.

  That is, as shown in FIG. 15, the reception-side wireless communication apparatus 2 receives a transmission signal of a QPSK modulated wave from a transmission-side wireless communication apparatus (not shown) via a wireless line, and the carrier synchronization circuit 4 Outputs a reproduction clock signal, an Ich component and a baseband signal of the Qch component to the QPSK modulated wave identification circuit 6 based on the received QPSK modulated wave.

  The A / D converters 8a and 8b of the QPSK modulated wave identification circuit 6 convert the baseband signals into digital signals and output them to the identification table circuit 10 and the phase difference detection circuit 12, respectively. The identification table circuit 10 outputs an identification circuit pattern corresponding to each baseband signal to the identification output selection circuit 14. The phase difference detection circuit 12 calculates the phase difference of the QPSK modulated wave due to the switching from the active device to the standby device of the transmission-side wireless communication device based on the input baseband signals. An identification output selection signal based on the phase difference is output to the identification output selection circuit 14. The identification output selection circuit 14 outputs Ich and Qch demodulated signals based on the input identification circuit pattern and the identification output selection signal.

JP-A-4-74043

  In the above-described reception-side wireless communication device 2 of Patent Document 1, if the transmission signal is a QPSK system, the transmission-side wireless communication device can be used as an element of the impact that occurs before and after switching from the active device to the standby device. The reception-side wireless communication device 2 can absorb the phase difference offset of the transmission signal.

  Here, the offset of the transmission signal generated before and after switching includes an offset related to the phase difference of the transmission signal (hereinafter referred to as phase offset) and an offset related to the gain of the transmission signal (hereinafter referred to as gain offset). Is included.

  However, when the transmission signal is a signal of another multilevel modulation system, the reception-side wireless communication device 2 instantaneously detects the phase difference of the transmission signal at the time of switching, or the identification output from the identification table circuit 10 It is difficult to quickly output the identification circuit pattern to the selection circuit 14, and as a result, the phase offset of the transmission signal cannot be absorbed by the reception-side wireless communication device 2.

  Further, the reception-side wireless communication device 2 cannot cope with the gain offset of the transmission signal before and after switching.

  The present invention has been made in order to solve the above-described problem. Regardless of the transmission signal modulation method, the transmission signal generated at the time of switching from the active device to the standby device in the transmission-side wireless communication device is provided. An object of the present invention is to provide a wireless entrance system that can absorb an offset by a receiving-side wireless communication device.

  The wireless entrance system according to the present invention is a wireless entrance system that transmits a transmission signal from a transmitting-side wireless communication device to a receiving-side wireless communication device via a wireless line, wherein the transmitting-side wireless communication device includes an active device and a standby system. The receiving-side wireless communication device includes a switching advance notice signal detection means, a carrier recovery circuit, an AGC circuit, a phase difference estimation circuit, and a gain difference estimation circuit, and the transmission signal includes transmission data, and the current use A switching advance notice signal inserted into the transmission data in order to notify the receiving-side wireless communication apparatus of the switch from the standby system apparatus to the standby system apparatus, and the standby system apparatus from the active system apparatus after insertion of the switching advance notice signal. And an estimation signal inserted into the transmission data to notify the receiving-side wireless communication device that the switching has been performed, and the active device is configured to transmit the transmission data. The switching notice signal is inserted into data, and the standby system apparatus inserts the estimation signal into the transmission data when switching from the active system apparatus to the standby system apparatus after insertion of the switching notice signal, Switching notice signal detection means determines a timing at which the receiving wireless communication apparatus receives the estimated signal based on the detected switching notice signal, and holds the carrier regeneration circuit and the AGC circuit based on the determined timing. The phase difference estimation circuit estimates a phase offset of the transmission signal before and after switching when the reception-side wireless communication apparatus receives the estimation signal, and the estimated phase offset is input to the carrier recovery circuit. The gain difference estimation circuit outputs the transmission signal before and after switching when the reception-side wireless communication apparatus receives the estimation signal. The in-offset is estimated and the estimated gain offset is output to the AGC circuit. The carrier recovery circuit skips the input phase offset and then releases its own hold state. The AGC circuit In this case, the hold state is canceled after skipping the input gain offset.

  According to this configuration, since not only the estimation of the phase offset but also the estimation of the gain offset is performed, the gain offset can be absorbed by the reception-side wireless communication device. In other words, deviations in the power level of the transmission signal before and after switching can be absorbed by the reception-side wireless communication device. As a result, the reception-side radio communication apparatus can absorb the offset (phase offset and gain offset) of the transmission signal configured by a multi-level modulation scheme other than the QPSK scheme.

  Further, since the AGC circuit and the carrier recovery circuit skip by the offsets during the hold state, gain control and carrier recovery can be performed on the transmission signal without being affected by the offsets.

  Here, the phase difference estimation circuit includes a first phase rotation unit, a second phase rotation unit, and a phase estimation unit, and the first phase rotation unit is included in the first to fourth quadrants on the constellation. The phase direction of the estimated signal with respect to the predetermined reference phase set in the detected quadrant is detected by detecting in which quadrant the estimated signal is located and comparing the Qch component and the Ich component of the estimated signal And rotating the estimation signal around the reference phase by a predetermined first angle in the direction opposite to the phase direction to reverse the magnitude relationship between the Qch component and the Ich component, and the second phase rotation unit includes: The estimation signal rotated by the first angle is rotated in the phase direction every second angle smaller than the first angle, and the magnitude relationship between the Qch component and the Ich component is reversed again at the reference phase. The phase estimation unit estimates and estimates the phase offset based on the phase difference of the estimation signal with respect to the reference phase calculated by {first angle−second angle × (number of rotations of the second angle)}. The phase offset is preferably output to the carrier recovery circuit.

  Thereby, the estimation speed of the phase offset is improved, and the phase offset can be estimated in a short time. The reference phase is a phase of a transmission signal before switching, which is a known signal.

  The gain difference estimation circuit includes a power calculation unit and a multiplication determination unit, and the power calculation unit compares a magnitude relationship between a predetermined reference power on the constellation and the power of the estimation signal, and When the power of the estimated signal is greater than the reference power, the multiplication determining unit decreases the estimated signal power for each predetermined power value, and the magnitude relationship between the estimated signal power and the reference power is reversed. , {Estimated signal power−power value × (number of power value reductions)} is the power difference of the estimated signal with respect to the reference power, while the power of the estimated signal is greater than the reference power. If it is smaller, the estimated signal power is increased for each predetermined power value, and when the magnitude relationship between the estimated signal power and the reference power is reversed, {estimated signal power + power value × (number of power value increases) } Power difference calculated by Is the power difference of the estimated signal with respect to the reference power, the gain offset is estimated based on the power difference, and the estimated gain offset is output to the AGC circuit.

  This makes it possible to estimate the gain offset before and after switching from the active device to the standby device. The reference power refers to the power of the transmission signal before switching, which is a known signal.

  Further, the receiving-side wireless communication device further includes an estimated signal receiving circuit, the switching notice signal detecting means outputs the timing to the estimated signal receiving circuit, and the estimated signal receiving circuit is inputted When the estimated signal is received based on timing, the Qch component and the Ich component of the estimated signal are averaged, and the average values of the Qch component and the Ich component are averaged by the phase difference estimation circuit and the gain difference estimation. The phase difference estimation circuit estimates the phase offset based on the input average values, and the gain difference estimation circuit determines the gain offset based on the input average values. Is preferably estimated.

  Furthermore, the transmission-side wireless communication device further includes a switching control unit that outputs a switching control signal to each of the active device and the standby device, and the active device is based on the input switching control signal. Preferably, the switch notice signal is inserted into the transmission data, and the standby device inserts the estimation signal into the transmission data based on the input switching control signal.

  Furthermore, when the transmission-side radio communication device transmits a radio frame as the transmission signal to the reception-side radio communication device, the switching notice signal and the estimation signal are transmitted at the timing at which a frame synchronization signal is inserted. It is preferable to be inserted into the.

  According to the present invention, not only the phase offset but also the gain offset is estimated, so that the gain offset can be absorbed by the receiving-side radio communication device. As a result, the reception-side radio communication apparatus can absorb the offset of the transmission signal configured by a multi-level modulation scheme other than the QPSK scheme.

  A preferred embodiment of the wireless entrance system according to the present invention will be described below with reference to the accompanying drawings. Prior to the description, the configuration of the wireless entrance system which is a premise of the present embodiment and its problems will be described. Will be described.

  First, the configuration of the wireless entrance system 50 that is a premise of the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is an overall block diagram of a communication system 52 including a wireless entrance system 50. FIG. 2 is a block diagram showing an internal configuration of radio entrance devices (radio communication devices) 54 and 56 arranged on the transmission side and the reception side of the radio entrance system 50, respectively.

  The wireless entrance system 50 is provided to securely connect a line wirelessly in an area (for example, between the main island and a remote island) where it is difficult to connect the line using a wired public line network or a telephone network. As shown in FIG. 1, a wireless entrance device (transmission-side wireless communication device) 54 and an antenna 58 are respectively arranged on the transmission side (left side of FIG. 1) of the communication system 52, while the reception side thereof A wireless entrance device (reception-side wireless communication device) 56 and an antenna 60 are respectively disposed on the right side of FIG. The wireless entrance device 54 is connected from the antenna 58 to the receiving-side antenna 60 and the wireless entrance device 56 via the wireless line 62.

  In addition to the wireless entrance device 54 and the antenna 58 described above, for example, a base station 64 and a multiplexer (MUX) 68 in which an antenna 66 is installed are arranged on the transmission side of the communication system 52. The multiplexer 68 and the wireless entrance device 54 are arranged. Are connected via an optical fiber cable 70.

  On the other hand, on the reception side of the communication system 52, in addition to the above-described wireless entrance device 56 and antenna 60, for example, a multiplexer 72, 74, 78, and a wireless entrance system 76 and an antenna 82 having the same configuration as the wireless entrance system 50 are installed. Each base station 80 is arranged. In this case, the wireless entrance device 56 and the multiplexer 72 are connected via an optical fiber cable 84, and the multiplexer 72 and the multiplexer 74 are connected via a public line network 86 such as a telephone line, and the multiplexer 74 and the wireless entrance system 76 are connected. Are connected via an optical fiber cable 88, and the wireless entrance system 76 and the multiplexer 78 are connected via an optical fiber cable 90.

  In this communication system 52, by using the wireless entrance systems 50 and 76, the mobile phone 94 connected to the antenna 66 of the base station 64 via the wireless line 92 and the antenna 82 of the base station 80 via the wireless line 96. It is possible to transmit transmission data such as the contents of a call between the mobile phone 98 connected in this manner.

  FIG. 2 is a block diagram showing the internal configuration of the radio entrance devices 54 and 56. The radio entrance device (not shown) of the radio entrance system 76 (see FIG. 1) has the same configuration as the radio entrance devices 54 and 56. Here, the configuration of the wireless entrance device 54 will be described as a representative.

  The wireless entrance device 54 transmits / receives an interface unit 100, a transmission active device 102a, a transmission standby device 102b, a reception active device 104a, a reception standby device 104b, and a monitoring control unit 110. Part 112.

  Here, the call contents of the caller of the mobile phone 94 (see FIG. 1) are transmitted as transmission data from the mobile phone 94 to the antenna 66 of the base station 64 via the radio line 92, and the multiplexer 68 is connected to the optical fiber cable 70. When generating a frame signal corresponding to the transmission speed (for example, STM-1) and including the transmission data, and converting the frame signal from an electrical signal to light and outputting it to the interface unit 100, the interface unit 100 The input light is converted into an electrical signal, and the transmission data included in the frame signal is output to the transmission active device 102a and the transmission standby device 102b via the hybrid unit (HYB) 120, respectively. .

  The transmission active device 102a includes a modulation unit 126a including a transmission radio frame processing unit 122a and a frame modulation unit (MOD) 124a, and a frequency conversion unit (TX) 128a. On the other hand, the standby device for transmission 102b has the same configuration as that of the active device for transmission 102a, and includes a modulation unit 126b including a transmission radio frame processing unit 122b and a frame modulation unit 124b, and a frequency conversion unit 128b. . The transmission / reception unit 112 includes a switch 130, a transmission filter 132, a reception filter 134, a low noise amplifier 136, and a hybrid unit 138.

  The transmission radio frame processing units 122a and 122b insert a frame synchronization signal into the input transmission data to generate first and second radio frames (transmission signals), respectively, and the generated first and second radios The frame is output to the frame modulators 124a and 124b. The frame modulators 124a and 124b perform digital modulation by superimposing a carrier wave signal of a predetermined frequency (for example, 400 [MHz]) on the input first and second radio frames, and the modulated first and second frames are modulated. Two radio frames are output to the frequency converters 128a and 128b. The frequency conversion units 128a and 128b convert the input first and second radio frames into signals having a frequency higher than the predetermined frequency (for example, 10 [GHz]).

  Here, when the transmission active device 102a and the transmission filter 132 are connected by the switching operation of the switch 130 by the monitoring control unit 110, the frequency conversion unit 128a converts the frequency-converted first radio frame into the switch 130. And output to the antenna 58 via the transmission filter 132. As a result, the first radio frame is transmitted as a radio wave from the antenna 58 via the radio line 62 to the antenna 60 on the receiving side.

  On the other hand, when the transmission standby system device 102b and the transmission filter 132 are connected by the switching operation of the switch 130 by the monitoring control unit 110, the frequency conversion unit 128b converts the frequency-converted second radio frame into the switch 130 and The signal is output to the antenna 58 via the transmission filter 132. As a result, the second radio frame is transmitted as a radio wave from the antenna 58 via the radio line 62 to the receiving-side antenna 60.

  On the other hand, the call contents of the caller of the cellular phone 98 (see FIG. 1) are transmitted as transmission data to the radio entrance device 56, and the first or second radio frame including the transmission data is transmitted from the antenna 60 through the radio line 62. When transmitted as a radio wave to the antenna 58, the radio frame converted from the radio wave to an electric signal by the antenna 58 passes through the reception filter 134 and is amplified by the low noise amplifier 136. The amplified radio frame is hybridized. The data are output to the reception active device 104a and the reception standby device 104b via the unit 138, respectively.

  The reception-use active device 104a includes a frequency conversion unit (RX) 140a, and a demodulation unit 146a including a frame demodulation unit (DEM) 142a and a reception radio frame processing unit 144a. On the other hand, the reception standby device 104b has the same configuration as that of the reception active device 104a, and includes a frequency conversion unit 140b, and a demodulation unit 146b including a frame demodulation unit 142b and a reception radio frame processing unit 144b. .

  Here, when the reception active device 104a and the interface unit 100 are connected by the switching operation of the switch 150 in the interface unit 100 by the monitoring control unit 110, the frequency conversion unit 140a of the reception active device 104a is: The first or second radio frame obtained by converting the input first or second radio frame into a signal (eg, 400 [MHz]) having a frequency lower than a predetermined frequency (eg, 10 [GHz]). The frame is output to the frame demodulation unit 142a. The frame demodulator 142a demodulates the input first or second radio frame and outputs the demodulated radio frame to the reception radio frame processor 144a. The reception radio frame processing unit 144a extracts the transmission data from the first or second radio frame based on the frame synchronization signal included in the input first or second radio frame, and extracts the extracted transmission data. The data is output to the interface unit 100. The interface unit 100 generates an STM-1 frame signal including the input transmission data, converts the generated frame signal from an electrical signal to light, and converts the converted light via an optical fiber cable 70. Output to the multiplexer 68.

  When the reception standby system device 104b is connected to the interface unit 100 by the switching operation of the switch 150 in the interface unit 100 by the monitoring control unit 110, the reception standby system device 104b is connected to the reception active system device 104a. Similarly, the transmission data is extracted from the received first or second radio frame, and the extracted transmission data is output to the interface unit 100.

  The monitoring control unit 110 (1) monitors and controls the interface unit 100, the transmission active device 102a, the transmission standby device 102b, the reception active device 104a, the reception standby device 104b, and the transmission / reception unit 112. (2) By controlling the switching operation of the switches 130 and 150, the device operating in the wireless entrance device 54 is changed from the active device of the transmission active device 102a and the active device of reception 104a to the standby system for transmission. Switch to the standby system of the device 102b and the reception standby system 104b, or switch from the standby system to the active system.

  The above is the description regarding the configuration of the wireless entrance system 50.

  Next, problems of the wireless entrance system 50 will be described with reference to FIGS.

  In order to ensure the reliability of the entire system, the radio entrance system 50, as shown in FIG. 2, includes an active system device for transmission 102a and an active device for reception 104a, a standby system device for transmission 102b, A set preliminary configuration including the standby system device of the reception standby system device 104b is employed. In this case, as described above, the standby devices (the standby device for transmission 102b and the reception device for transmission) are received from the active device (the active device for transmission 102a and the active device for reception 104a) by the switching operation of the switches 130 and 150. Switching to the standby system device 104b) or switching from the standby system device to the active system device is possible.

  For such switching, (1) during maintenance work of the wireless entrance device 54, switching from the active system device to the standby system device or operation from the standby system device by the operation of the supervisory control unit 110 by an operator. (2) When the active device is abnormal, the active device is automatically switched from the active device to the standby device by the switching operation of the switches 130 and 150 based on the control of the monitoring controller 110. Alternatively, there is automatic switching that switches from the standby system device to the active system device.

  Here, since the manual switching is assumed to be performed when the wireless entrance device 54 is normal, it is possible to reduce the impact on the receiving side to the wireless line 62 and the wireless entrance device 56 at the time of switching as much as possible. A switching method is required.

  Further, switching between the active system device and the standby system device is performed by transmitting side switching for switching between the active system device for transmission 102a and the standby system device for transmission 102b by the switching operation of the switch 130, and the switching operation of the switch 150. There is reception side switching for switching between the reception active device 104a and the reception standby device 104b.

  In the following description, a description will be given of the transmission-side switching in which the impact on the reception side during switching is a problem, particularly the case of switching from the transmission active device 102a to the transmission standby device 102b. In this case, it is assumed that the switch 150 on the reception side does not perform the switching operation, and the interface unit 100 is connected to the reception active device 104a and the reception standby device 104b. In addition, the first wireless frame is output from the transmission active device 102a to the transmission / reception unit 112 before switching the switch 130, and the second wireless frame is output from the transmission standby device 102b to the transmission / reception unit 112 after switching. To do.

  Furthermore, in the following description, it is assumed that the first and second radio frames are transmitted from the transmission side (the radio entrance device 54 side in FIG. 1) of the communication system 52 to the reception side (the radio entrance device 56 side in FIG. 1). explain.

  FIG. 3 shows five offset elements that cause an impact applied to the reception side {wireless entrance device 56 (see FIGS. 1 and 2)} by switching from the transmission active device 102a to the transmission standby device 102b. It is the block diagram which illustrated.

  2 and 3, when the connection between the transmission-use active device 102 a and the transmission / reception unit 112 is switched to the connection between the transmission standby-system device 102 b and the transmission / reception unit 112 by the switching operation of the switch 130, Between the first radio frame output from the transmission active device 102a to the transmission / reception unit 112 and the second radio frame output from the transmission standby device 102b to the transmission / reception unit 112, The five offset elements are generated.

  That is, the five offset elements are (1) the timing difference between the first and second radio frames in the transmission radio frame processing units 122a and 122b, and (2) the carrier signal in the frame modulation units 124a and 124b (described above). 400 [MHz] signal) frequency error and phase difference, frequency converter 128a, 128b high frequency signal (10 [GHz] signal described above) frequency error and phase difference, (3) frame modulator 124a, 124b And the delay difference between the first and second radio frames in the frequency converters 128a and 128b, (4) the switching time from the transmission active device 102a to the transmission standby device 102b, and (5) the transmission active device 102a. Power of the first radio frame output from the transmission / reception unit 112 to the transmission / reception unit 112 and the second radio frame output from the transmission standby system device 102b to the transmission / reception unit 112 Which is a deviation of the frame of power.

  The timing difference (1) described above is caused by the timing of energization from the power source (not shown) to the transmission radio frame processing units 122a and 122b. The frequency error and phase difference in (2) are caused by the wiring pattern in the frame modulators 124a and 124b and the frequency converters 128a and 128b. If such frequency error and phase difference exist, The phase difference of the second radio frame increases. The delay difference (3) is caused by the wiring pattern in the frame modulators 124a and 124b and the frequency converters 128a and 128b. If such a delay difference exists, the order of the first and second radio frames is increased. The phase difference increases. The switching time (4) is the time from the switching time of the switch 130 until the second radio frame is stabilized. The deviation of (5) is caused by the structure of the transmission active device 102a and the transmission standby device 102b.

  Therefore, in the radio entrance device 56 on the receiving side, when switching from the transmission active device 102a to the transmission standby device 102b, between the first and second radio frames due to the offset elements (1) to (5). In order to reliably absorb the phase offset and gain offset (impact) of the transmission and efficiently extract the transmission data from the first and second radio frames, the first radio frame from the transmission active device 102a and the transmission It is necessary to establish frame synchronization with the second radio frame from the standby apparatus 102b.

  The following two methods (A) and (B) are considered as a switching method on the transmission side necessary for obtaining the frame synchronization.

  In the method (A), the first and second radio frames are synchronized, the carrier frequency is synchronized, and the high frequency signal is synchronized between the transmission active device 102a and the transmission standby device 102b. The phase offset and gain offset of the first and second radio frames generated at the time of switching are minimized, and as a result, the first active device 104a for reception and the standby device 104b for reception of the first in the radio entrance device 56 And transmission data input to the frame demodulation units 142a and 142b within the holding time of the second radio frame and the synchronization holding time of the STM-1 frame signal in the interface unit 100 of the radio entrance device 56. (Hereinafter referred to as a high-speed pull-in method or hitless switching method).

  In the method (B), before the switch 130 is switched, the first radio frame is configured by inserting a switching notice signal for notifying the wireless entrance device 56 to switch the transmission data, and when the switch 130 is switched (after switching). In addition, an offset estimation signal notifying the radio entrance device 56 that the switching is completed is inserted into the transmission data to form a second radio frame, and the first and second radio frames are transmitted to the radio entrance device 56. (Hereinafter referred to as errorless switching). As a result, the demodulation units 146a and 146b of the wireless entrance device 56 can instantaneously absorb the phase offset and gain offset generated at the time of switching on the receiving side, and the interface unit 100 includes the STM-1 including the transmission data. It is possible to prevent the occurrence of an error when generating the frame signal.

  However, the high-speed pull-in method (A) does not require a sequence between transmission and reception, and has an advantage that an error frequent occurrence time of an STM-1 frame signal is shortened. And a change in the propagation path due to rainfall, etc.) and the hardware configuration for synchronizing the carrier frequency and the high-frequency signal is complicated.

  On the other hand, the error-less switching method of (B) has an advantage that the quality of the wireless line 62 at the time of switching is ensured, but it is easily influenced by the state of the wireless line 62 as in the high-speed pull-in method of (A). In addition, the hardware configuration for synchronizing the carrier frequency and the high-frequency signal is complicated, and the switching sequence is complicated.

  Furthermore, in (A) and (B), the above-mentioned (1) to (5) that occur when the switch 130 is switched as the modulation scheme of the first and second radio frames is a multilevel modulation scheme and has a higher symbol rate. ), It is difficult to cope with the offset element.

  Therefore, regardless of the modulation schemes of the first and second radio frames, the offsets (phase offsets and phase offsets) of the first and second radio frames generated before and after switching from the active device for transmission 102a to the standby device for transmission 102b. A wireless entrance system that can efficiently absorb (gain offset) by the wireless entrance device 56 on the receiving side is desired.

  The above is the description regarding the problem of the wireless entrance system 50.

  Next, the wireless entrance system 160 according to the present embodiment will be described with reference to FIGS. Note that the same components as those of the wireless entrance system 50 (see FIGS. 1 to 3) and the reception-side wireless communication device 2 (see FIG. 15) according to the conventional technology are the same. The detailed description is abbreviate | omitted.

  This wireless entrance system 160 is a system that adopts the above-mentioned (A) high-speed pull-in method and (B) error-less switching method and has improved the disadvantages of (B). As shown in FIG. 56, the switch 162 is arranged in the transmission / reception unit 112, and the switching control signal is output from the monitoring control unit (switching control unit) 110 to the transmission radio frame processing units 122a and 122b. On the other hand, as shown in FIG. In the demodulating units 146a and 146b of the radio entrance devices 54 and 56, the radio entrance which is the premise of the present embodiment is that the phase offset and gain offset estimation processing before and after switching is performed based on the detection of the switching notice signal. It differs from the system 50 (refer FIGS. 1-3).

  4 and 5, in order to facilitate the illustration of the characteristic configuration of the wireless entrance system 160 according to the present embodiment, the same components as those of the wireless entrance system 50 that is the premise of the present embodiment are as follows. Some of them are omitted.

  In the following description, the radio entrance device 54 digitally modulates the first and second radio frames (transmission signals) by the PSK method, and the radio channel 62 (see FIG. 1) is used for the modulated first and second radio frames. It is assumed that data is transmitted to the wireless entrance device 56 via the network. In the wireless entrance device 54, it is assumed that the various synchronizations described above are established between the transmission active device 102a and the transmission standby device 102b.

  In FIG. 4, when the monitoring control unit (switching control unit) 110 supplies a switching control signal for instructing the transmission radio frame processing units 122a and 122b of the transmission active device 102a to output the first radio frame, Based on the input switching control signal, the transmission radio frame processing unit 122a inserts a switching advance notice signal into the transmission data from the interface unit 100 (see FIG. 2) at the timing of inserting the frame synchronization signal. One radio frame is generated. Further, the transmission radio frame processing unit 122a outputs a first switching timing signal instructing switching of the switch 130 to the switch 162 based on the input switching control signal.

  The switch 162 outputs the input first switching timing signal to the switch 130 as a third switching timing signal. The switch 130 connects the transmission active device 102a and the transmission filter 132 (see FIG. 2) based on the input third switching timing signal. As a result, the first radio frame that has been digitally modulated by the frame modulator 124 a and frequency-converted by the frequency converter 128 a is output to the transmission filter 132 via the switch 130.

  On the other hand, when the monitoring control unit 110 supplies a switching control signal for instructing the transmission radio frame processing units 122a and 122b to output the second radio frame, the transmission radio frame processing unit 122b receives the input Based on the switching control signal, an estimated signal is inserted into transmission data from the interface unit 100 (see FIG. 2) at the timing of inserting a frame synchronization signal to generate a second radio frame, and an instruction to switch the switch 130 is given. The second switching timing signal is output to the switch 162.

  The switch 162 outputs the second switching timing signal input instead of the first switching timing signal to the switch 130 as a third switching timing signal. Based on the input third switching timing signal, the switch 130 connects the active device for transmission 102a and the transmission filter 132 (see FIG. 2), and connects the standby device for transmission 102b and the transmission filter 132. Switch to. As a result, the second radio frame that has been digitally modulated by the frame modulator 124 b and frequency-converted by the frequency converter 128 b is output to the transmission filter 132 via the switch 130.

  Therefore, in the radio entrance device 54, as shown in the time chart of FIG. 6, the time zone in which the transmission active device 102a (see FIG. 4) and the transmission / reception unit 112 are connected (the “active device in FIG. 6”). In the "transmission by 102a" time zone), a switch warning signal is inserted into the transmission data from the transmission-use active device 102a via the transmission / reception unit 112 (see FIGS. 2 and 4) and the wireless line 62 (see FIG. 1). The first radio frame configured as described above is transmitted to the radio entrance device 56.

  Next, at a time when a predetermined time has passed since the insertion of the switching notice signal, the transmission standby unit 102b and the transmission / reception unit 112 are connected by switching the switch 130 based on the switching control signal. As a result, when the switch 130 is switched, the estimation signal is inserted into the transmission data to generate a second radio frame, and the generated second radio frame is transmitted from the transmission standby system device 102b to the transmission / reception unit 112 (FIG. 2 and FIG. 2). 4) and the wireless line 62 (see FIG. 1).

  Further, since the wireless entrance system 160 employs (A) a high-speed pull-in method, as shown in FIG. 4, between the transmission wireless frame processing units 122a and 122b, the first and second wireless frames are transmitted. Frame synchronization is performed, the frequency and phase of the carrier wave signal are synchronized between the frame modulators 124a and 124b, and the frequency and phase of the high-frequency signal are synchronized between the frequency converters 128a and 128b.

  On the other hand, as shown in FIG. 5, the frame demodulation units 142a and 142b of the radio entrance device 56 on the receiving side include a carrier synchronization circuit 4, A / D converters 8a and 8b, an AGC circuit 170, a complex multiplication circuit 172, and a carrier regeneration circuit. 174, a determination circuit 176, an estimation signal reception circuit 178, a phase difference estimation circuit 180, and a gain difference estimation circuit 182. In addition, the reception radio frame processing units 144 a and 144 b include a switching notice signal detection unit 184.

  When the first and second radio frames are transmitted from the radio entrance device 54 (see FIGS. 1, 2, and 4) to the radio entrance device 56 via the radio line 62, the carrier synchronization circuit 4 performs frequency conversion. The first and second radio frames input from the units 140a and 140b are converted into baseband signals of Ich components and Qch components, and the baseband signals of the Ich components are output to the A / D converter 8a. The baseband signal of the Qch component is output to the A / D converter 8b. The carrier synchronization circuit 4 also generates a recovered clock signal from the first and second radio frames, and the generated recovered clock signal is received by the radio frame processing units 144a and 144b, the estimated signal receiving circuit 178, the phase difference It outputs to the estimation circuit 180 and the gain difference estimation circuit 182 respectively.

  The A / D converter 8a digitally converts the input baseband signal of the Ich component and outputs it to the AGC circuit 170, while the A / D converter 8b converts the input baseband signal of the Qch component. Digitally convert and output to AGC circuit 170.

  The AGC circuit 170 controls the gain of a variable gain amplifier (not shown), and outputs it to the complex multiplication circuit 172 while maintaining the level of each input baseband signal at a predetermined level.

  The complex multiplication circuit 172 multiplies the input baseband signals of the Ich component and Qch component by the carrier wave signal generated by the carrier recovery circuit 174 to perform synchronous detection of the baseband signals and perform synchronous detection. The baseband signals are output to the determination circuit 176.

  Based on the baseband signals output from the complex multiplier circuit 172, the carrier recovery circuit 174 and the carrier signal superimposed on the baseband signals of the Ich component and the Qch component input to the complex multiplier circuit 172 The same carrier signal is reproduced, and the reproduced carrier signal is output to the complex multiplication circuit 172.

  The determination circuit 176 uses the basebands of the Ich component and the Qch component based on the input reproduction clock signal so that the transmission radio frame processing units 144a and 144b can extract the transmission data and the switching notice signal. The signal is converted into a serial data signal and output to the reception radio frame processing units 144a and 144b.

  The reception radio frame processing units 144a and 144b extract the transmission data from the first and second radio frames input as the serial data signal based on the input reproduction clock signal, and the extracted transmission data The data is output to the interface unit 100.

  In this case, when the switch notice signal detection means 184 extracts the switch notice signal from the first radio frame, the switch notice signal 184 is wirelessly transmitted by the switching operation of the switch 130 at a time after a predetermined time has elapsed from the detection time of the switch notice signal. It is determined that the device that outputs the frame is switched from the active device for transmission 102a to the standby device for transmission 102b, and the estimated signal is received by the estimated signal receiving circuit 178 at the time of switching.

  Therefore, based on the determination, the switching notice signal detection means 184 provides the AGC circuit 170 with an AGC hold signal for temporarily stopping the gain control operation in the AGC circuit 170 for a predetermined period before and after the switch 130 is switched. In addition to outputting, a carrier reproduction hold signal for temporarily stopping the carrier signal reproduction output operation in the carrier reproduction circuit 174 for the predetermined period is output to the carrier reproduction circuit 174. Further, the switching notice signal detecting means 184 notifies the estimated signal receiving circuit 178 that the time after the predetermined time has elapsed since the detection of the switching notice signal is the timing for receiving the estimated signal.

  Here, the predetermined time from the detection time determined by the switching notice signal detection means 184 is that the monitoring control unit 110 (see FIG. 4) of the wireless entrance device 54 outputs a switching control signal to the transmission wireless frame processing unit 122a. Then, it corresponds to the time until the switching control signal is output to the transmission radio frame processing unit 122b (see FIG. 6). Accordingly, these predetermined times can be set in advance by the monitoring control unit 110 and the switching notice signal detecting means 184.

  Further, as described above, the switching notice signal detection means 184 sends the AGC hold signal and the carrier reproduction hold signal to the AGC circuit 170 and the carrier reproduction circuit 174 before the estimated signal reception time in the estimated signal reception circuit 178. As shown in FIG. 6, the predetermined period before and after switching of the switch 130 is due to the impact of the phase offset and gain offset generated at the time of switching of the switch 130 from the predetermined time before switching of the switch 130. This refers to the period up to the time when the occurrence of error ends (see “control period by switching notice signal” shown in FIG. 6). Therefore, if the operations of the AGC circuit 170 and the carrier regeneration circuit 174 are temporarily held only during this period, the influence of the impact can be avoided.

  When the estimated signal receiving circuit 178 acquires the estimated signal based on the input timing and the recovered clock signal, the estimated signal receiving circuit 178 keeps the baseband signals of the Ich component and the Qch component output from the complex multiplier circuit 172 constant. Time acquisition, each average value of each acquired baseband signal is calculated, the calculated average values of the Ich component and Qch component, and the timing at which the averaging of each signal level is completed are phase difference estimation circuit 180 and Each is output to the gain difference estimation circuit 182.

  Here, the fixed time refers to a time during which the estimated signal is inserted into the transmission data. Therefore, the estimated signal receiving circuit 178 captures each baseband signal of the Ich component and the Qch component related to the estimated signal. (See FIG. 6). Therefore, the averaging end timing is the insertion end time of the estimated signal.

  The phase difference estimation circuit 180 is based on a phase difference between a phase (reference phase) serving as a reference in any one of the first to fourth quadrants on the constellation and a phase of an estimation signal on the quadrant. , A circuit for estimating the phase offset of the first and second radio frames, and includes a first rotation unit 186, a second rotation unit 188, and a phase estimation unit 190. The reference phase refers to the phase of the first radio frame before switching of the switch 130, which is a known signal.

  The first rotating unit 186 detects which quadrant of the estimated signal is in the constellation based on the average values of the Ich component and the Qch component related to the input estimated signal and the averaging end timing. Then, the phase direction of the estimated signal with respect to a reference phase (for example, any one of 45 °, 135 °, 225 °, and 315 °) preset in the detected quadrant is detected. Next, the first rotating unit 186 rotates the estimated signal around the reference phase by a predetermined first angle (for example, 22.5 °) in the direction opposite to the phase direction, and the magnitude relationship between the average values. , And the average values obtained by the reverse rotation are output to the second rotating unit 188.

  The second rotating unit 188 rotates the input estimation signal having each average value in the phase direction every second angle (for example, 1 °) smaller than the first angle, After the magnitude relationship between the Ich component and the Qch component is reversed again, the first angle, the second angle, the number of rotations n of the second angle, and the reference phase are output to the phase estimation unit 190.

  The phase estimation unit 190 calculates {first angle−second angle × (number of rotations of the second angle) from the input first angle, second angle, number of rotations n of the second angle, and the reference phase. n)} is the phase difference of the estimated signal with respect to the reference phase. Here, since the reference phase is the phase of the first radio frame, the phase difference is a phase offset of the first and second radio frames. Therefore, the phase estimation unit 190 outputs the estimated phase offset to the carrier recovery circuit 174.

  The gain difference estimation circuit 182 determines the first and second radio signals based on the deviation between the reference power on the constellation (reference power) and the power of the estimated signal on the constellation (estimated signal power). This is a circuit for estimating a gain offset of a frame, and has a power calculation unit 192 and a multiplication determination unit 194. Note that the reference power refers to the power of the first radio frame before switching of the switch 130, which is a known signal.

  The power calculation unit 192 compares the estimated signal power with the reference power, compares the reference power and the estimated signal power with information about whether the estimated signal power is larger or smaller than the reference power. Are output to the multiplication determination unit 194.

  When the input information is information that the estimated signal power is larger than the reference power, the multiplication determining unit 194 decreases the estimated signal power for each predetermined power value, and the estimated signal power When the magnitude relation between the reference power and the reference power is reversed, a numerical value calculated by {estimated signal power−power value × (number of reductions of the power value)} is set as a power difference of the estimated signal with respect to the reference power. .

  On the other hand, when the input information is information that the estimated signal power is smaller than the reference power, the multiplication determining unit 194 increases the estimated signal power for each predetermined power value, and the estimated signal power And the reference power, the numerical value calculated by {estimated signal power + power value × (number of increases in the power value)} is the power difference of the estimated signal with respect to the reference power. .

  Further, the multiplication determining unit 194 estimates the gain offset of the first and second radio frames based on the calculated power difference, and outputs the estimated gain offset to the AGC circuit 170.

  The carrier regeneration circuit 174 holds the estimated signal reception circuit 178 before obtaining the estimated signal based on the input carrier regeneration hold signal, stops the carrier signal regeneration process, and after a predetermined time has elapsed, When a phase offset is input, the carrier signal is skipped by the amount of the phase offset, and then the own hold state is released (see FIG. 6).

  On the other hand, the AGC circuit 170 stops the gain control based on the input AGC circuit hold signal before acquiring the estimated signal by the estimated signal receiving circuit 178 and stops the gain control. When this is done, the baseband signals of the Ich component and Qch component are skipped by the amount of the gain offset, and then the own hold state is released (see FIG. 6).

  Here, the time after the lapse of the predetermined time is the end time of the error section described above.

  Next, the basic operation of the wireless entrance device 56 before and after the switching of the switch 130 will be described with reference to FIGS.

  In the radio entrance device 56 shown in FIG. 5, as described above, when the first radio frame is received from the radio entrance device 54 (see FIGS. 1, 2 and 4) via the radio line 62, the switching notice signal When the detection means 184 detects the switching notice signal from the first radio frame, the switching notice signal detection means 184 detects the time (timing) at which the switch 130 switches from the detection time of the switching notice signal, and before this timing, the carrier The reproduction hold signal is output to the carrier reproduction circuit 174 to stop the reproduction process of the carrier signal of the carrier reproduction circuit 174, while the AGC circuit hold signal is output to the AGC circuit 170, and the gain of the AGC circuit 170 is Control is stopped (see FIG. 6). Further, the switching notice signal detecting means 184 outputs the timing to the estimated signal receiving circuit 178.

  When the estimated signal receiving circuit 178 acquires the estimated signal based on the input timing, the estimated signal receiving circuit 178 calculates an average value of the baseband signals of the Ich component and the Qch component related to the estimated signal, The average value and the averaging end timing that is the insertion completion time of the estimated signal are output to the phase difference estimating circuit 180 and the gain difference estimating circuit 182, respectively.

  The phase difference estimation circuit 180 estimates the phase offsets of the first and second radio frames within an error interval based on each of the inputted average values and the averaging end timing, and the estimated phase offset is calculated as the error. The signal is output to the carrier reproduction circuit 174 at the end time of the section. The carrier recovery circuit 174 cancels its own hold state after skipping the carrier signal by the amount of the input phase offset.

  On the other hand, the gain difference estimation circuit 182 estimates the gain offsets of the first and second radio frames within the error interval based on the inputted average values and the averaging end timing, and calculates the estimated gain offset. Output to the AGC circuit 170 at the end time of the error section. The AGC circuit 170 cancels its own hold state after skipping the baseband signals of the Ich component and the Qch component by the input gain offset.

  Next, the phase offset estimation operation in the phase difference estimation circuit 180 will be described with reference to FIGS. 7 to 11, and the gain offset estimation operation in the gain difference estimation circuit 182 will be described with reference to FIGS. While explaining.

  Here, as shown in FIG. 7, it is assumed that a constellation in which 64QAM symbols 200 can be arranged, and one of the symbols 200 is a symbol 202 of an estimated signal. In FIG. 7, the distal point of 45 ° with respect to the coordinate origin O and the Ich coordinate axis is the symbol 202 of the estimation signal.

  First, the phase offset estimation operation in the phase difference estimation circuit 180 (see FIG. 5) will be described.

  FIG. 8 is a flowchart for explaining the phase offset estimation operation. FIG. 9 is a graph showing a state where the symbol 202 of the estimation signal and the center axis 204 of the reference phase are plotted on the constellation. FIG. 10 is a graph for explaining the operation of the first rotating unit 186. FIG. 11 is a graph for explaining the operation of the second rotating unit 188.

  Here, it is assumed that the center axis 204 of the reference phase and the symbol 202 of the estimation signal are arranged in the second quadrant of the constellation as shown in FIG. 9, and the reference phase is 135 ° with respect to the Ich coordinate axis. explain. In addition, the coordinates of the symbol 202 are (I1, Q1). Further, it is assumed that the phase of the symbol 202 is advanced with respect to the central axis 204 of the reference phase. These values I1 and Q1 are average values of the Ich component and the Qch component of the estimation signal input to the first rotating unit 186 (see FIG. 5).

  In FIG. 8, the first rotating unit 186 (see FIG. 5) detects in which quadrant of the constellation the symbol 202 exists (step S1). In this case, the first rotating unit 186 determines that the symbol 202 (see FIG. 9) exists in the second quadrant based on the coordinates (I1, Q1), and sets the reference phase (135 °) and its phase in the second quadrant. The central axis 204 is set. When the symbol 202 exists in another quadrant (first, third, or fourth quadrant), the reference phase and the central axis 204 are set in the other quadrant.

  Next, the first rotating unit 186 detects the phase direction of the symbol 202 with respect to the central axis 204 based on the positional relationship between the central axis 204 and the coordinates (I1, Q1) in the second quadrant. In this case, the phase direction can be specified by comparing the magnitude relationship between the absolute values of I1 and Q1 (step S2). That is, if | I1 |> | Q1 |, the phase of the symbol 202 of the estimated signal is ahead of the center axis 204 of the reference phase (see FIG. 9), so the first rotating unit 186 It is determined that the reference phase is offset in the positive rotation direction (+ direction).

  Next, as shown in FIG. 10, the first rotating unit 186 (see FIG. 5) moves the symbol 202 around the central axis 204 in the direction opposite to the phase direction (− direction), based on the determination result of the phase direction. ) By a predetermined first angle (step S3 in FIG. 8). In this case, the first angle is preferably larger than the phase difference between the central axis 204 and the symbol 202. In FIG. 10, the symbol 202 is rotated in the − direction by −22.5 ° (first angle). ing.

  As a result, the symbol of the estimated signal changes from the symbol 202 to the symbol 206 due to the rotation, and when the coordinates (I1, Q1) of the symbol 202 and the coordinates (I2, Q2) of the symbol 206 are compared, The magnitude relationship with the Qch component is reversed. That is, by changing the symbol 202 that was in the relationship of | I1 |> | Q1 | in FIG. 9 to the symbol 206 by rotating the symbol 202 by the first angle, the relationship of | I2 | <| Q2 | It becomes.

  Here, when the first angle is set to −22.5 °, since the magnitude relationship between the Ich component and the Qch component is reversed, the first rotating unit 186 (see FIG. 5) It is determined that the phase offset of the estimation signal with respect to the reference phase is between 22.5 ° and 0 ° (see FIG. 10).

  Then, the first rotation unit 186 outputs the coordinates (I1, Q1) of the symbol 202, the coordinates (I2, Q2) of the symbol 206, and the reference phase of the central axis 204 to the second rotation unit 188.

  In the second rotation unit 188 (see FIG. 5), based on the input coordinates (I1, Q1), coordinates (I2, Q2) and the reference phase, as shown in FIG. 206 is rotated every predetermined second angle in the phase direction (step S4 in FIG. 8). In this case, since the symbol 206 is present in the − direction with respect to the central axis 204, the second rotating unit 188 moves the symbol 206 in the + direction to + 1 ° (second) smaller than the first angle (22.5 °). Rotate every angle).

  As a result, when the symbol 206 is rotated n times, the symbol 206 changes to the symbol 208 in the positive direction with respect to the central axis 204, and the magnitude relationship between the Ich component and the Qch component is reversed again. That is, when the coordinates (In, Qn) of the symbol 208 and the coordinates (I2, Q2) of the symbol 206 are compared, the symbol 206 having the relationship of | I2 | <| Q2 | in FIG. By changing the symbol 208 by n rotations every time, the relationship | In |> | Qn | shown in FIG. 11 is obtained.

  Then, the second rotating unit 188 (see FIG. 5) sends the first angle, the second angle, the number of rotations n of the second angle, and the reference phase of the central axis 204 to the phase estimating unit 190. Output.

  The phase estimation unit 190 uses the input first angle, the second angle, the rotation number n of the second angle, and the reference phase of the central axis 204 (see FIGS. 9 to 11), A phase difference of the estimation signal with respect to the reference phase is calculated based on a mathematical formula of {first angle (22.5 °) −second angle (1 °) × n + 135 °} (step S5). As described above, since the reference phase is the phase of the first radio frame before the switch 130 (see FIGS. 2 and 4) is switched, the phase estimation unit 190 calculates the phase difference of the calculated estimation signal. The phase offsets of the first and second radio frames are estimated, and the estimated phase offset is output to the carrier recovery circuit 174 (see FIG. 5) (step S6).

  The above description is the description of the phase offset estimation operation when the phase of the estimation signal is ahead of the reference phase, but on the negative direction side of the central axis 204 (see FIGS. 9 to 11) of the reference phase. If there is the symbol 202, it is detected that the phase direction of the symbol 202 is the negative direction with respect to the central axis 204 in step S2 of FIG. The symbol 206 is rotated by .5 ° (first angle) to be changed to the symbol 206. In step S4, the symbol 206 is rotated every -1 ° (second angle). In step S5, {first angle (22.5 The phase offset is calculated on the basis of the following equation: °) + second angle (1 °) × n + 135 °}.

  The above description is the description of the phase offset estimation operation in the phase difference estimation circuit 180 (see FIG. 5).

  Next, the gain offset estimation operation in the gain difference estimation circuit 182 will be described with reference to FIGS.

  FIG. 12 is a flowchart for explaining the gain offset estimation operation. FIG. 13 is a graph showing a state in which the symbol 202 of the estimated signal and the circle 210 of the reference power are plotted on the constellation. FIG. 14 is a graph for explaining the operation of the multiplication determining unit 194 (see FIG. 5).

  Here, as shown in FIG. 13, a case will be described in which the symbol 202 of the estimation signal is outside the radius of the circle 210 of the reference power centered on the coordinate origin O. Note that the radius of the circle 210 indicates the magnitude of the reference power.

In step S7 of FIG. 12, the power calculator 192 (see FIG. 5) compares the magnitude relationship between the estimated signal power (I1 ² + Q1 ² ) ^1/2 on the constellation and the reference power. As shown in FIG. 13, since the estimated signal power is larger than the reference power, the power calculator 192 (see FIG. 5) determines that the estimated signal power is larger than the reference power and the estimated signal power. The reference power is output to the multiplication determination unit 194.

Next, based on the input information, the multiplication determining unit 194 decreases the estimated signal power for each predetermined power value and brings the symbol 202 closer to the circle 210 as shown in FIG. 14 (FIG. 12). Step S8). In this case, when the symbol of the estimated signal power moves inward from the circle 210 and changes to the symbol 212, the magnitude relationship between the estimated signal power and the reference power is reversed. That is, the reduction number of the power value and m, if the coordinates of the symbol 212 (Im, Qm) and the estimated signal power (Im ² + Qm ^{2) 1/2} a relationship of <reference power. Accordingly, the multiplication determining unit 194 calculates the power difference of the estimated signal with respect to the reference power based on the formula {estimated signal power−power value × (number of times the power value is reduced m)} (step S9).

  Here, as described above, since the reference power is the power of the first radio frame before switching of the switch 130 (see FIGS. 2 and 4), the power difference is the first and second radio frames. Gain offset. Therefore, the multiplication determining unit 194 (see FIG. 5) estimates the calculated power difference as the gain offset of the first and second radio frames, and outputs the estimated gain offset to the AGC circuit 170.

In the above description, the estimation operation of the gain offset when the relationship of the estimated signal power (I1 ² + Q1 ² ) ^1/2 > reference power is described, but the estimated signal power (I 1 ² + Q1 ² ) ^1/2 <If the relationship is the reference power, in step S8 of FIG. 12, the estimated signal power is increased for each predetermined power value, and when the number of increases is m times, the estimated signal power and the reference power are When the magnitude relationship is reversed, in step S9, a gain offset is calculated based on the formula {estimated signal power + power value × (number of increases in the power value m)}.

  As described above, according to the radio entrance system 160 according to the present embodiment, not only the phase offset but also the gain offset is estimated, the transmission side active device 102a in the transmission side radio entrance device 54 and the transmission offset are transmitted. It is possible to absorb the gain offset that occurs before and after switching with the trusted standby system device 102b by the radio entrance device 56 on the receiving side. In other words, the gain offset caused by the power level of the first radio frame and the power level of the second radio frame before and after switching can be absorbed by the radio entrance device 56 on the reception side. As a result, the radio entrance device 56 can absorb the offset (phase offset and gain offset) generated before and after switching in the multi-level modulation method other than the QPSK method.

  Further, since the AGC circuit 170 and the carrier recovery circuit 174 skip each offset during the hold state, the gain control and the carrier recovery are performed for the first and second radio frames without being affected by the offset. be able to.

  Furthermore, by estimating the phase offset using the phase difference estimation circuit 180, the phase offset can be estimated in a short time.

  Furthermore, by estimating the gain offset using the gain difference estimation circuit 182, it is possible to estimate the gain offset before and after switching from the transmission active device 102 a to the transmission standby device 102 b.

  Furthermore, since the first and second radio frames are generated by inserting the switching notice signal and the estimation signal into the transmission data at the timing of inserting the frame synchronization signal, the influence of the insertion on the transmission data is reduced. Is possible.

  Further, since the transmission data is subjected to error correction using an error correction code in the radio entrance device 56 on the receiving side in order to improve its reliability, the error occurrence section shown in FIG. By absorbing the phase offset and gain offset, the errorless switching can be performed efficiently regardless of the occurrence of an error.

  Of course, the wireless entrance system according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

It is a block diagram of the communication system containing the radio | wireless entrance system used as the premise of this embodiment. It is a block diagram of the radio | wireless entrance apparatus of FIG. It is a block diagram which shows the offset element which generate | occur | produces by switching from the active apparatus for transmission to the standby apparatus for transmission. It is a partial block diagram which shows the structure of the transmission side of the radio | wireless entrance system which concerns on this embodiment. It is a partial block diagram which shows the structure of the receiving side of the radio | wireless entrance system which concerns on this embodiment. 6 is a time chart showing transmission / reception of radio frames in the radio entrance system of FIGS. 4 and 5. It is a flowchart for demonstrating the estimation operation | movement of a phase offset. It is a graph which shows the constellation used for estimation of a phase offset and a gain offset. It is a graph which shows the state which plotted the symbol of the estimation signal, and the center axis of the reference phase on the constellation. It is a graph for demonstrating operation | movement of a 1st rotation part. It is a graph for demonstrating operation | movement of a 2nd rotation part. It is a flowchart for demonstrating the estimation operation | movement of a gain offset. It is a graph which shows the state which plotted the symbol of the estimation signal, and the circle | round | yen of reference electric power on the constellation. It is a graph for demonstrating operation | movement of a multiplication determination part. It is a block diagram of the receiving side radio | wireless communication apparatus concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 160 ... Wireless entrance system 162 ... Switch 170 ... AGC circuit 172 ... Complex multiplication circuit 174 ... Carrier reproduction circuit 176 ... Judgment circuit 178 ... Estimation signal receiving circuit 180 ... Phase difference estimation circuit 182 ... Gain difference estimation circuit 184 ... Switch notice signal detection Means 186 ... first rotating unit 188 ... second rotating unit 190 ... phase estimating unit 192 ... power calculating unit 194 ... multiplication determining unit

Claims (6)

In a wireless entrance system that transmits a transmission signal from a transmission-side wireless communication device to a reception-side wireless communication device via a wireless line,
The transmission side wireless communication device includes an active device and a standby device,
The reception-side wireless communication device includes a switching notice signal detection means, a carrier regeneration circuit, an AGC circuit, a phase difference estimation circuit, and a gain difference estimation circuit,
The transmission signal includes transmission data, a switching notification signal inserted into the transmission data to notify the receiving wireless communication device of switching from the active device to the standby device, and the switching notification signal. Including an estimated signal inserted into the transmission data to notify the receiving wireless communication device that the active device has been switched to the standby device after insertion,
The active device inserts the switching notice signal into the transmission data,
The standby device inserts the estimated signal into the transmission data at the time of switching from the active device to the standby device after insertion of the switching notice signal,
The switching notice signal detecting means determines a timing at which the receiving wireless communication apparatus receives the estimation signal based on the detected switching notice signal, and determines the carrier regeneration circuit and the AGC circuit based on the determined timing. Hold,
The phase difference estimation circuit estimates a phase offset of the transmission signal before and after switching when the reception-side wireless communication apparatus receives the estimation signal, and outputs the estimated phase offset to the carrier recovery circuit. ,
The gain difference estimation circuit estimates a gain offset of the transmission signal before and after switching when the reception-side wireless communication device receives the estimation signal, and outputs the estimated gain offset to the AGC circuit;
The carrier regeneration circuit skips the input phase offset and then releases its own hold state.
The AGC circuit skips an amount corresponding to the input gain offset and then releases its own hold state. The wireless entrance system according to claim 1, wherein
The phase difference estimation circuit includes a first phase rotation unit, a second phase rotation unit, and a phase estimation unit,
The first phase rotation unit detects in which quadrant the first to fourth quadrants on the constellation, and compares the Qch component and the Ich component of the estimated signal, A phase direction of the estimated signal with respect to a predetermined reference phase set in the detected quadrant is detected, and the Qch is rotated about the reference phase by a predetermined first angle in a direction opposite to the phase direction. Reverse the magnitude relationship between the component and the Ich component,
The second phase rotation unit rotates the estimation signal rotated by the first angle in the phase direction every second angle smaller than the first angle, and the Qch component and the Ich at the reference phase. Reverse the magnitude relationship of the components again,
The phase estimation unit estimates and estimates the phase offset based on a phase difference of the estimation signal with respect to the reference phase calculated by {first angle−second angle × (number of rotations of the second angle)}. The wireless entrance system, wherein the phase offset is output to the carrier recovery circuit. The wireless entrance system according to claim 1 or 2,
The gain difference estimation circuit includes a power calculation unit and a multiplication determination unit,
The power calculator compares the magnitude relationship between a predetermined reference power on the constellation and the power of the estimated signal,
When the power of the estimated signal is greater than the reference power, the multiplication determining unit decreases the estimated signal power for each predetermined power value, and the magnitude relationship between the estimated signal power and the reference power is reversed. In addition, the power difference calculated by {estimated signal power−power value × (number of power value reductions)} is the power difference of the estimated signal with respect to the reference power, while the power of the estimated signal is greater than the reference power. When the estimated signal power is increased for each predetermined power value, and the magnitude relationship between the estimated signal power and the reference power is reversed, {estimated signal power + power value × (number of power value increases) )} Is used as the power difference of the estimated signal with respect to the reference power, the gain offset is estimated based on the power difference, and the estimated gain offset is output to the AGC circuit. Wireless Entrance system according to claim. The radio entrance system according to any one of claims 1 to 3,
The receiving-side wireless communication device further includes an estimated signal receiving circuit,
The switching notice signal detecting means outputs the timing to the estimated signal receiving circuit,
When the estimated signal is received based on the inputted timing, the estimated signal receiving circuit averages the Qch component and the Ich component of the estimated signal, and averages the Qch component and the Ich component. Are respectively output to the phase difference estimation circuit and the gain difference estimation circuit,
The phase difference estimation circuit estimates the phase offset based on each of the inputted average values,
The gain difference estimation circuit estimates the gain offset based on each of the inputted average values. In the radio | wireless entrance system of any one of Claims 1-4,
The transmission-side wireless communication device further includes a switching control unit that outputs a switching control signal to the active device and the standby device,
The active device inserts the switching notice signal into the transmission data based on the input switching control signal,
The standby system apparatus inserts the estimation signal into the transmission data based on the input switching control signal. In the radio | wireless entrance system of any one of Claims 1-5,
When the transmission side wireless communication device transmits a wireless frame as the transmission signal to the reception side wireless communication device, the switching notice signal and the estimation signal are inserted into the transmission data at a timing of inserting a frame synchronization signal. This is a wireless entrance system.

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