JP7455461B2 - wireless receiving device - Google Patents

Description

The present invention relates to a radio receiving device, and particularly to a radio receiving device as a mechanism related to reception in a radio communication device.

As a technology related to wireless communication devices, for example, a main signal modulated by an arbitrary multi-level modulation method and an auxiliary signal modulated by a modulation method with a phase number equal to or less than the number of phases of the multi-level modulation of this main signal. is time-division multiplexed, auxiliary signals are placed in multiple consecutive symbols at the beginning of each frame, followed by the main signal, and auxiliary signals are placed dispersed at regular intervals within the main signal. Input a digital modulated wave, convert the frequency of this digital modulated wave using a reproduced carrier signal, detect the phase error of the frequency-converted signal, and adjust the frequency and phase of the reproduced carrier so that the phase error is reduced. In a carrier regeneration circuit that performs carrier regeneration by controlling, there is a frame detection means for detecting the beginning of a frame of a digital modulated wave, and a frame detection means for detecting the beginning of a frame of a digital modulated wave, and a frame detection means for detecting the beginning of a frame from an auxiliary signal of a plurality of consecutive symbols at the beginning of the frame based on the frame detection timing detected by this means. A first phase error detection means for determining a first phase error of the reproduced carrier; and a second phase error of the reproduced carrier from an auxiliary signal dispersed in the main signal based on the frame detection timing detected by the frame detection means. and a second phase error detection means for determining the error, the frequency of the reproduced carrier is pulled in by the first phase error determined by the first phase error detection means, and the frequency of the reproduced carrier is pulled in by the first phase error determined by the first phase error detection means. A device is known in which the phase of the reproduced carrier is pulled in using a phase error of 2 (Patent Document 1).

Patent No. 3926945

By the way, in wireless communication equipment, amplifier systems related to transmission and reception (e.g., preamplifiers, power amplifiers) may momentarily drop in level due to fluctuations or vibrations in the power supply of the equipment, or vibrations in the equipment may cause frequency conversion problems. The carrier phase/local phase of the signal may momentarily slip (in other words, rotate). However, in conventional wireless communication devices, the purpose of the carrier regeneration method is to perform stable initial pull-in at startup, and does not guarantee stable operation against momentary abnormalities in the device. For this reason, in conventional wireless communication devices, as mentioned above, the amplifier system related to transmission and reception may momentarily drop in level, or the carrier phase/local phase for frequency conversion may momentarily slip. The problem arises that it cannot be addressed.

Therefore, the present invention operates the carrier regeneration loop stably by controlling the state of the carrier regeneration loop based on the detection results of instantaneous fluctuations in the level of the amplifier system related to transmission and reception and carrier phase/local phase slips. The purpose of the present invention is to provide a wireless receiving device that can perform the following functions.

In order to solve the above problem, the invention according to claim 1 includes a power drop detection unit that monitors the power of a received radio frame and determines whether or not there is a fluctuation in the power, and a power drop detection unit that monitors the phase state of the radio frame. a phase slip detection unit that determines whether or not there is a phase slip , and a numerically controlled oscillator that outputs a phase rotation control signal to a phase rotator that rotates the phase of the wireless frame; It has a carrier regeneration unit including a loop filter that outputs an error signal, and a switch capable of switching parameters to be supplied to the carrier regeneration unit, and the power drop detection unit detects fluctuations in the power of the radio frame. or when the phase slip detection section detects the phase slip of the radio frame, the switch switches the parameter to be supplied to the carrier regeneration section. .

The invention according to claim 2 is the wireless receiving device according to claim 1, in which the parameter is supplied to the loop filter, and a phase error detection range on a complex plane is set to a predetermined range. The phase error is

The invention according to claim 3 is characterized in that, in the wireless receiving device according to claim 1, the parameter is a loop filter coefficient indicating a loop bandwidth of a PLL, which is supplied to the loop filter. do.

The invention according to claim 4 is characterized in that, in the radio receiving apparatus according to claims 1 to 3, the modulation method of the radio frame is quadrature amplitude modulation.

According to the invention described in claim 1, the parameters supplied to the carrier regeneration section are switched when power fluctuation or phase slip of the radio frame is detected, so that carrier regeneration malfunction due to instantaneous equipment abnormality is avoided. (Specifically, loss of synchronization) can be prevented, and it is possible to stably operate the carrier regeneration unit and achieve good demodulation performance (in other words, bit error rate).

According to the second aspect of the invention, a phase error having predetermined characteristics can be set as a parameter by adjusting the phase error detection range on the complex plane, and the phase error can be used as a parameter to detect the carrier. By controlling the regeneration process, it is possible to accurately prevent carrier regeneration malfunctions (specifically, loss of synchronization) due to instantaneous abnormalities in the equipment.

According to the invention described in claim 3, by adjusting the loop bandwidth of the PLL, a loop filter coefficient having predetermined characteristics can be set as a parameter, and the loop filter coefficient can be used as a parameter to reproduce the carrier. By controlling the processing, it is possible to accurately prevent carrier regeneration malfunctions (specifically, loss of synchronization) due to momentary abnormalities in the equipment.

According to the invention set forth in claim 4, it is possible to achieve the above effects in wireless communication performed using the quadrature amplitude modulation method.

1 is a diagram showing a schematic configuration of a wireless communication system in an embodiment of the present invention. 1 is a functional block diagram showing a schematic configuration of a radio receiving device according to Embodiment 1 of the present invention. FIG. FIG. 2 is a diagram showing an example of a constellation of a radio frame (received signal) output from a receiving unit, and is a diagram illustrating a state in which the power and phase of the radio frame (received signal) are normal. FIG. 4 is a diagram illustrating a state in which the power of a radio frame is decreasing in the constellation of FIG. 3; FIG. 4 is a diagram illustrating a state in which the phase of a radio frame has slipped in the constellation of FIG. 3; 4 is a diagram illustrating a state in which the phase of a radio frame is stable in the constellation of FIG. 3. FIG. FIG. 3 is a conceptual diagram showing a detection method of an all-signal point detection section of the radio receiving device in FIG. 2; FIG. 3 is a conceptual diagram showing a detection method of a specific range detection section of the radio receiving device of FIG. 2; FIG. 3 is a diagram illustrating the operation of the wireless receiving device of FIG. 2. FIG. FIG. 2 is a functional block diagram showing a schematic configuration of a wireless receiving device according to Embodiment 2 of the present invention. FIG. 11 is a diagram illustrating the operation of the wireless receiving device in FIG. 10.

The present invention will be described below based on the illustrated embodiments. In addition, below, the characteristic structure of this invention is demonstrated, and the description of the structure similar to the past when performing wireless communication is abbreviate|omitted.

FIG. 1 is a diagram showing a schematic configuration of a wireless communication system 100 in an embodiment of the invention. FIG. 1 shows a schematic configuration of a wireless communication system 100 (upper side of FIG. 1), and functional blocks of a schematic configuration of a wireless communication device 101 disposed at each wireless communication transmitting/receiving station (lower side of FIG. 1). ).

A wireless communication device 101 and an antenna 102 are arranged at each of the wireless communication transmitting and receiving stations that constitute the wireless communication system 100 (see the upper side of FIG. 1). The wireless communication devices 101 are connected to each other by a wireless line 103 via an antenna 102 .

First, a schematic configuration of a wireless communication device 101 as a base configuration to which the wireless receiving device 1 is applied in this embodiment will be described.

The wireless communication device 101 includes a modulating section 120 and a transmitting section 130 for transmission, a receiving section 150 and a demodulating section 160 for receiving, and an interface section 110 (see the bottom of FIG. 1). .

Here, the wireless communication device 101 is a device that is equipped with a transmission mechanism and a reception mechanism and performs transmission and reception, and in the following explanation, processing related to transmission is performed using the transmission mechanism. The wireless communication device 101 in the case where the wireless communication device 101 performs the processing related to reception using the receiving mechanism is referred to as the “receiving side”.

The interface unit 110 mainly includes a data line termination device 111 (including equipment called a data communication device or a data line device). The interface unit 110 receives input of transmission data to be communicated, and outputs the transmission data to the modulation unit 120 via the data line termination device 111.

The modulating section 120 receives the transmission data output from the interface section 110, inserts a frame synchronization signal into the transmission data to generate a radio frame (transmission signal), and further adds a frame synchronization signal to the radio frame (transmission signal). A carrier wave signal of a predetermined frequency is superimposed, digitally modulated, and output. The modulator 120 performs digital modulation by superimposing a carrier signal having a frequency of, for example, about 400 MHz on the radio frame. Although the modulation method used in the wireless communication system 100 is not limited to a specific method, for example, quadrature amplitude modulation (QAM) is used.

The transmitter 130 receives the digitally modulated radio frame (transmission signal) output from the modulator 120, and converts the digitally modulated radio frame (transmission signal) from digital to analog using a D/A converter. Then, it is converted into a signal (transmission wave signal) with a higher frequency than the predetermined frequency (for example, about 400 MHz) using a local oscillator and a mixer. The transmitter 130 converts the digitally modulated radio frame into a signal having a frequency of, for example, about 10 GHz.

The transmitter 130 also passes the frequency-converted radio frame (transmission wave signal) through a transmission filter that passes only signals in a predetermined frequency band, amplifies it with a power amplifier, and then outputs it.

The radio frame (transmission wave signal) that has been digitally modulated in the modulation section 120 and frequency-converted in the transmission section 130 is guided from the transmission section 130 to the antenna 102 via the demultiplexer 140, and from the antenna 102 to the radio frame. It is transmitted as a radio wave to the antenna 102 of the other wireless communication device 101 (in other words, on the receiving side in this communication) via the line 103.

In addition, the wireless frame is transmitted from the antenna 102 of the other wireless communication device 101 (in other words, the transmitting side in this communication) via the wireless line 103 to the wireless communication device (in other words, the receiving side in this communication). When the received radio frame is transmitted as a radio wave to the antenna 102 of 101, the antenna 102 converts the received radio frame into an electrical signal (received wave signal) and outputs it.

A radio frame (received wave signal) output from the antenna 102 and converted into an electric signal is guided to the receiving section 150 via the duplexer 140.

The receiving unit 150 receives input of a radio frame (received wave signal), passes the radio frame (received wave signal) through a reception filter that passes only signals in a predetermined frequency band, and amplifies it with a preamplifier. The high frequency (eg, about 10 GHz) is converted into a signal of a lower frequency (eg, about 400 MHz) using a local oscillator and a mixer.

The receiving unit 150 further amplifies the frequency-converted signal with a power amplifier, performs analog-to-digital conversion with an A/D converter, and outputs a digital signal (radio frame (received signal)).

Note that the receiving unit 150 performs orthogonal detection processing on the radio frame (received wave signal) to generate an in-phase component (Ich) baseband signal and a quadrature component (Qch) baseband signal whose phases are orthogonal to each other. However, in the following explanation, unless it is necessary to focus on the in-phase component and the orthogonal component separately, the in-phase component and the orthogonal component will not be particularly distinguished and will be explained as contents common to both. Further, in the drawings, an in-phase component signal and a quadrature component signal are represented by one signal line.

The demodulation unit 160 receives the input of the radio frame (reception signal) output from the reception unit 150, demodulates the radio frame (reception signal), and also demodulates the frame inserted into the demodulated radio frame (reception signal). Transmission data is extracted from the radio frame (received signal) based on the synchronization signal, and the extracted transmission data is output to the interface section 110.

In the wireless communication system 100 described above, in the local oscillators of the transmitter 130 and the receiver 150, vibrations of the equipment cause instantaneous slip (in other words, rotation) of the carrier phase/local phase for frequency conversion. A problem arises. In the wireless communication system 100 described above, the power amplifier of the transmitting section 130 and the preamplifier and power amplifier of the receiving section 150 may experience instantaneous level fluctuations due to fluctuations in the power supply of devices (also called "momentary interruptions") or vibrations. The problem arises that a drop occurs and the constellation shrinks.

Therefore, the radio receiving device 1 according to the present invention detects instantaneous power fluctuations and carrier phase/local phase slips (in other words, rotations), and controls operations related to carrier regeneration based on the detection results. A mechanism is provided to prevent carrier regeneration malfunctions (specifically, loss of synchronization) due to device vibrations or instantaneous power fluctuations, and to stably perform processing related to carrier regeneration.

(Embodiment 1)
FIG. 2 is a functional block diagram showing a schematic configuration of radio receiving device 1 according to Embodiment 1 of the present invention. Note that while FIG. 2 is based on a configuration such as the wireless communication device 101 in the wireless communication system 100 described above (see FIG. 1), in consideration of clearly showing the characteristic configuration of the present invention, A part of the configuration of the wireless communication device 101 is omitted. Specifically, FIG. 2 shows a characteristic configuration applied to a configuration corresponding to the demodulation unit 160 between the reception unit 150 and the interface unit 110 of the wireless communication device 101 described above. It is shown as a wireless receiving device 1 as a mechanism related to.

The radio receiving device 1 according to this embodiment includes a power drop detection unit 2 that monitors the power of a received radio frame to determine whether there is a power fluctuation, and a power drop detection unit 2 that monitors the phase state of the radio frame to determine whether there is a phase slip. a phase slip detection unit 3 that determines the phase of the radio frame, and a numerically controlled oscillator 13 that outputs a phase rotation control signal to the phase rotator 11 that rotates the phase of the wireless frame; and a phase error signal to the numerically controlled oscillator 13. The carrier regeneration unit 10 includes a loop filter 12 that performs the following steps, and a carrier regeneration control switch 20 that can switch parameters to be supplied to the carrier regeneration unit 10. or when the phase slip detection section 3 detects a phase slip of the radio frame, the carrier regeneration control switch 20 switches the parameters to be supplied to the carrier regeneration section 10.

The radio receiving device 1 according to this embodiment further includes the above parameter being a phase error detected with the phase error detection range on the complex plane set to a predetermined range, which is supplied to the loop filter as 12. , I'm trying to do that.

The radio receiving device 1 according to this embodiment is a circuit that performs carrier wave regeneration processing in digital radio transmission, and mainly includes a power drop detection section 2, a phase slip detection section 3, and a carrier regeneration section 10. , and a carrier regeneration control switch 20.

The carrier regeneration unit 10 includes a phase rotator 11, a loop filter 12, and a numerically controlled oscillator 13. In the radio receiving apparatus 1, the phase rotator 11, symbol determination section 4, error calculation section 5, loop filter 12, and numerically controlled oscillator 13 constitute a carrier recovery loop that is PLL (abbreviation for Phase Locked Loop).

The phase rotator 11 has a function of rotating the phase of the analog-to-digital converted radio frame (received signal) output from the receiving section 150. Specifically, the phase rotator 11 performs phase rotation on the radio frame (received signal) based on a sine wave or cosine wave as a phase rotation control signal output from the numerically controlled oscillator 13. Phase error compensation is performed, and a phase error compensated signal is generated and output.

The loop filter 12 is a filter that removes high frequency components of the phase error signal output from the carrier regeneration control switch 20 according to a predetermined loop bandwidth. Specifically, the loop filter 12 receives the input of the phase error signal after setting a predetermined loop filter coefficient, removes unnecessary high frequency components from the phase error signal, and removes unnecessary high frequency components from the phase error signal. A phase error signal is output to the frequency control terminal of the numerically controlled oscillator 13.

The numerically controlled oscillator 13 (also referred to as "NCO (abbreviation for Numerical Controlled Oscillator)") generates a phase signal for performing phase error compensation by phase rotation based on the phase error signal output from the loop filter 12 after removing high frequency components. Equipped with a function to generate rotation control signals. Specifically, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal with an opposite phase based on the phase error signal after high frequency component removal output from the loop filter 12, and outputs the generated phase rotation control signal as a sine wave signal or a cosine wave signal. A sine wave signal and a cosine wave signal are output to the phase rotator 11. The phase rotation by the phase rotator 11 is controlled by the phase rotation control signal output from the numerically controlled oscillator 13.

The power drop detection unit 2 monitors the power (in other words, signal strength) of the radio frame (received signal) output from the phase rotator 11 of the carrier regeneration unit 10, and detects power that may cause equipment malfunction. Determine whether there is a change in

For example, when the modulation method used in the wireless communication system 100 is multi-value quadrature amplitude modulation (multi-value QAM; specifically, 16QAM, 64QAM, 256QAM), the determination of the presence or absence of power fluctuation can be made by: It is conceivable that this is performed based on the degree of constellation contraction with respect to the rectangular frame of multilevel QAM that corresponds to the case where the power is in a normal state (see FIGS. 3 and 4). In FIGS. 3 to 6, the horizontal axis is the I-axis of the complex plane, which corresponds to the in-phase component (Ich) after orthogonal detection processing, and the vertical axis is the Q-axis of the complex plane, which corresponds to the orthogonal Corresponds to the orthogonal component (Qch) after detection processing.

The determination of whether there is a power fluctuation may be made based on the average value of power over a predetermined length of time, or the number of consecutive symbols whose power is less than a predetermined value (specifically, For example, it may be performed based on the number of times (about 2 to 10 times).

When the power drop detection unit 2 detects a power fluctuation that may cause equipment malfunction, it sends a power fluctuation notification signal to the carrier regeneration control switch 20 to notify that a power fluctuation has occurred. Output. After detecting the power fluctuation, the power drop detection unit 2 also detects that the power fluctuation has subsided and the power has returned to normal, and then performs a power recovery function to notify that the power has returned to normal. A notification signal is output to the carrier regeneration control switch 20.

The phase slip detection section 3 monitors the phase state of the radio frame (received signal) output from the phase rotator 11 of the carrier regeneration section 10 and determines whether there is a phase slip. The determination of the presence or absence of a phase slip is made using a known pattern signal inserted into transmission data in the wireless communication device 101 on the transmitting side. For example, when the modulation method used in the wireless communication system 100 is multi-value quadrature amplitude modulation (multi-value QAM; specifically, 16QAM, 64QAM, 256QAM), the phase is It is conceivable to determine the presence or absence of a phase slip based on the proportion of signal points that protrude outside the rectangular frame of multilevel QAM in a normal state (see FIGS. 3 and 5). The ratio of the signal points used to determine whether or not there is a phase slip is not limited to a specific value, but may be set to an appropriate value after taking into consideration the characteristics of the communication equipment and modulation method, for example. will be set appropriately.

In the case of a phase slip, the phase state is not determined, and the distribution of signal points fluctuates by lagging behind or leading the rectangular frame of multilevel QAM when the phase is in a normal state. Signal points protrude into all areas around the rectangular frame of multilevel QAM (see FIG. 5). On the other hand, when the phase slip has subsided and the phase is stable, the distribution of signal points that protrude outside the rectangular frame of the multi-value QAM when the phase is in a normal state is the same as that of the multi-value QAM. It consistently lags or advances with respect to the rectangular frame, and is biased toward a specific area outside the rectangular frame of the multilevel QAM (see FIG. 6; in FIG. 6, area 1 is the phase Area 2 is an area where signal points protrude when the phase is rotating in a leading direction, and area 2 is an area where signal points protrude when the phase is rotating in a lag direction). Therefore, it may be possible to determine the presence or absence of a phase slip by taking into account the distribution of signal points that protrude outside the rectangular frame of multilevel QAM.

When the phase slip detection section 3 detects a phase slip, it outputs a slip notification signal to the carrier regeneration control switch 20 to notify that a phase slip has occurred. After detecting a phase slip, the phase slip detection unit 3 also performs phase recovery to notify that the phase state has returned to normal when it detects that the phase slip has subsided and the phase state has returned to normal. A notification signal is output to the carrier regeneration control switch 20.

The symbol determination unit 4 performs symbol determination on the signal output from the phase rotator 11 of the carrier recovery unit 10, the phase of which has been rotated by the phase rotator 11 and phase error compensation has been performed.

The error calculation unit 5 calculates the phase error between the ideal symbol and the received symbol for the signal output from the symbol determination unit 4. Specifically, the error calculation section 5 is constituted by a subtracter.

The decoding unit 6 receives the signal output from the symbol determining unit 4, performs error correction decoding processing on the signal, and outputs transmission data generated by the decoding processing to the interface unit 110.

The carrier regeneration control switch 20 has a function of selecting one of the signals output from each of the all signal point detection section 21 , the hold output section 22 , and the specific range detection section 23 and supplying it to the loop filter 12 . Be prepared. The carrier regeneration control switch 20 connects to any one of the all signal point detection section 21, the hold output section 22, and the specific range detection section 23 according to the signals output from the power drop detection section 2 and the phase slip detection section 3. Switch.

The carrier regeneration control switch 20 is normally connected to the all signal point detection section 21 that detects phase errors for all signal points on the complex plane, and is connected to the loop filter 12 of the carrier regeneration section 10 (and , to the numerically controlled oscillator 13), and the phase error related to all signal points (a signal expressing the phase error related to all signal points as a voltage value is referred to as a "full range phase error signal") as a parameter supplied to the carrier regeneration unit 10. ).

In this case, the loop filter 12 removes unnecessary high frequency components from the full range phase error signal supplied from the full signal point detection section 21 via the carrier regeneration control switch 20, and removes unnecessary high frequency components from the full range phase error signal after removing the high frequency components. A signal is output to the frequency control terminal of the numerically controlled oscillator 13. Then, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal of opposite phase based on the full range phase error signal after high frequency component removal output from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13, on the analog-to-digital converted radio frame (received signal) output from the reception unit 150. . That is, the carrier reproducing section 10 performs carrier reproducing processing using the full range phase error signal supplied from the all signal point detecting section 21.

As shown in FIG. 7, the all signal point detection unit 21 detects all signal points S2 on the complex plane within a predetermined range (“phase error detection range W1 It has a function to detect the phase error within the Note that the reference point is also called an ideal point.

That is, a plurality of reference points S1 are arranged vertically and horizontally at equal intervals on a complex plane in advance, and rectangular shapes centered on each reference point S1 are arranged so as to divide each reference point S1 at equal intervals vertically and horizontally. The phase error detection range W1 is set densely (see FIG. 7). Then, the all-signal point detection unit 21 calculates a phase error indicating how far the signal point S2 deviates from the reference point S1 in the leading direction or the delayed direction in each phase error detection range W1. To detect. Note that when there is no phase error, the reference point S1 and the signal point S2 overlap each other. Here, only the signal point S2 located within the phase error detection range W1 is detected, and the signal point S2 located outside the phase error detection range W1 is not detected.

In such an all-signal point detection unit 21, since the phase error is detected for all the signal points S2 on the complex plane, the phase error can be detected with high accuracy, but the phase error detection range W1 becomes narrow due to high multi-value If this happens, unstable operation may occur due to instantaneous equipment abnormalities such as power fluctuations or phase slips, which may lead to loss of synchronization in carrier regeneration.

The carrier regeneration control switch 20 is also connected to the all signal point detection unit 21 and supplies a full range phase error signal to the loop filter 12 (and by extension to the numerically controlled oscillator 13). , when the power fluctuation notification signal output from the power drop detection section 2 is input, or when the slip notification signal output from the phase slip detection section 3 is input, the regeneration hold signal is stored in advance. The connection is switched to the output section 22, and a reproduced hold signal is outputted to the loop filter 12 of the carrier reproducing section 10 as a parameter to be supplied to the carrier reproducing section 10.

Note that after the carrier regeneration control switch 20 is connected to the hold output section 22 and outputs the regeneration hold signal to the loop filter 12, the power fluctuation notification signal output from the power drop detection section 2 is further inputted, Alternatively, if the slip notification signal output from the phase slip detection section 3 is further input, the loop filter 12 of the carrier regeneration section 10 is sent to the carrier regeneration section 10 while being connected to the hold output section 22. A playback hold signal is output as a parameter to be supplied.

The regeneration hold signal is a signal for temporarily holding the carrier regeneration loop in the carrier regeneration unit 10, and is a signal that instructs the loop filter 12 to temporarily stop the high frequency component removal operation and output operation. Alternatively, the signal may set the loop bandwidth of the PLL in the loop filter 12 to be extremely narrow.

When the loop filter 12 receives the regenerated hold signal output from the hold output section 22 via the carrier regeneration control switch 20, it stops the operation of removing the high frequency component of the phase error signal and the output operation, or stops the operation of removing the high frequency component of the phase error signal and the output operation. A predetermined frequency component of the phase error signal is removed while the loop bandwidth of the phase error signal is extremely narrowed. Note that by setting the loop bandwidth of the PLL used in the high frequency component removal processing by the loop filter 12 to be extremely narrow, the PLL lock time (i.e., the time until synchronization is achieved) is lengthened, and the carrier regeneration unit 10 It is possible to hold the carrier regeneration loop in a pseudo manner.

The carrier regeneration control switch 20 further connects to the hold output section 22 and outputs the regeneration hold signal to the loop filter 12, and then receives the power recovery notification signal output from the power drop detection section 2. Alternatively, when the phase recovery notification signal output from the phase slip detection section 3 is input, the signal is connected to the specific range detection section 23 that detects a phase error for signal points located within a specific range on the complex plane. The loop filter 12 of the carrier regeneration unit 10 (and by extension, the numerically controlled oscillator 13) receives the phase related to signal points located within a specific range as a parameter to be supplied to the carrier regeneration unit 10. An error (a signal expressing a phase error regarding signal points located within a specific range as a voltage value is referred to as a "specific range phase error signal") is supplied.

As shown in FIG. 8, the specific range detection unit 23 detects a signal point S2 located outside a region of a first radius C1 centered on the origin on the complex plane (i.e., the intersection of the I axis and the Q axis). and a signal point S2 located within an area of a second radius C2 centered on the origin on the complex plane and smaller than the first radius C1. It has the function to

That is, on a complex plane in which a plurality of reference points S1 are pre-arranged vertically and horizontally at equal intervals, outside the area of the first radius C1 centered on the origin, the reference point S1 and the corresponding signal point S2 are The number (for example, 3 points in FIG. 8) is small. Similarly, on a complex plane in which a plurality of reference points S1 are pre-arranged vertically and horizontally at equal intervals, within a region of a second radius C2 (C2≪C1) centered on the origin, the reference point S1 and this The number of signal points S2 corresponding to (for example, 3 points in FIG. 8) is small. In other words, such a small number of reference points S1 and signal points S2 are to be detected, and the sizes of radius C1 and radius C2 are set so that unstable operation does not occur.

In such a region where there are few reference points S1 and signal points S2, the phase error detection range (in other words, the detectable range) is wide, so it is unstable due to momentary equipment abnormalities such as power fluctuations and phase slips. This makes it possible to prevent and suppress a situation in which the movement is less likely to occur and the carrier regeneration becomes out of synchronization. In other words, by determining the direction of shift of the signal point S2 with respect to the reference line L with an inclination angle of 45 degrees, it is possible to reliably detect whether the phase is rotating in the leading direction or in the delayed direction. Furthermore, by calculating the amount of deviation and rotation of the signal point S2 from the reference line L, it becomes possible to reliably detect the amount of phase error. On the other hand, since phase errors are detected only for a small number of signal points S2, the accuracy of phase error detection is low.

It should be noted that the phase error is detected only at the signal point S2 located outside the region of the first radius C1, or the phase error is detected only at the signal point S2 located within the region of the second radius C2, or Whether or not to detect a phase error at both signal points S2 is determined based on the required accuracy, the predicted amount of phase error, and the like.

Further, the detection of phase errors by the all signal point detection section 21 and the specific range detection section 23 is always performed in parallel, and the all signal point detection section 21 sends a full range phase error signal to the carrier regeneration control switch 20. is constantly supplied, and a specific range phase error signal is also constantly supplied from the specific range detection section 23.

The loop filter 12 removes unnecessary high frequency components from the specific range phase error signal supplied from the specific range detection unit 23 via the carrier regeneration control switch 20, and numerically controls the specific range phase error signal after the high frequency component has been removed. It is output to the frequency control terminal of the oscillator 13. Then, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal of opposite phase based on the specific range phase error signal after removing the high frequency component output from the loop filter 12, and outputs it as a phase rotation control signal. The phase rotator 11 performs phase rotation, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13, on the analog-to-digital converted radio frame (received signal) output from the reception unit 150. . That is, the carrier reproducing section 10 performs carrier reproducing processing using the specific range phase error signal supplied from the specific range detecting section 23.

The carrier regeneration control switch 20 is connected to the specific range detection unit 23 and supplies the specific range phase error signal to the loop filter 12 (and by extension to the numerically controlled oscillator 13), and when the power decreases. A predetermined period of time has elapsed since the power recovery notification signal output from the detection unit 2 was input (excluding cases where the power recovery notification signal was not input), and the phase slip detection unit 3 outputs the power recovery notification signal. When a predetermined period of time has elapsed since the phase recovery notification signal was input (excluding cases where the phase recovery notification signal was not input), connection with the all signal point detection unit 21 is established for normal carrier regeneration. Then, a full range phase error signal is supplied to the loop filter 12 of the carrier regeneration unit 10 (and by extension, to the numerically controlled oscillator 13) as a parameter to be supplied to the carrier regeneration unit 10.

Note that when the specific range phase error output from the specific range detection section 23 becomes less than a predetermined threshold, the carrier regeneration control switch 20 is switched to connection with the all signal point detection section 21, and the carrier regeneration is started. A full range phase error signal may be supplied to the loop filter 12 of the section 10 (and by extension to the numerically controlled oscillator 13) as a parameter to be supplied to the carrier regeneration section 10.

Further, while the carrier regeneration control switch 20 is connected to the specific range detection section 23 and supplies the specific range phase error signal to the loop filter 12 (and by extension to the numerically controlled oscillator 13), When the power fluctuation notification signal output from the power drop detection section 2 is input, or when the slip notification signal output from the phase slip detection section 3 is input, the connection with the hold output section 22 is made. Then, a reproduced hold signal is output to the loop filter 12 of the carrier reproducing unit 10 as a parameter to be supplied to the carrier reproducing unit 10.

Next, the operation and effect of the radio receiving device 1 having such a configuration will be described with reference to FIG. 9 as well.

First, a wireless frame transmitted from another wireless communication device 101 (the wireless communication device 101 on the transmitting side in this communication) via the wireless line 103 is sent to the wireless communication device 101 (the wireless communication device 101 on the receiving side in this communication). ) is being received. At this time, normally, the carrier regeneration control switch 20 of the wireless communication device 101 on the receiving side connects to the all signal point detection section 21 and controls the loop filter 12 of the carrier regeneration section 10 (by extension, the numerical control The loop filter 12 removes high frequency components from the full range phase error signal supplied from the carrier regeneration control switch 20 and outputs it. Further, the numerically controlled oscillator 13 generates an opposite phase sine wave signal or cosine wave signal based on the full range phase error signal after removing the high frequency component output from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerically controlled oscillator 13 on the analog-to-digital converted radio frame (received signal) output from the receiving unit 150. ing. That is, the carrier reproducing section 10 performs carrier reproducing processing using the full range phase error signal supplied from the all signal point detecting section 21 (step S0).

When the wireless communication device 101 on the receiving side receives a wireless frame transmitted from the wireless communication device 101 on the transmitting side via the wireless line 103, the receiving unit 150 of the wireless communication device 101 on the receiving side performs frequency conversion and analog-to-analog conversion. Outputs digitally converted wireless frames (received signals). Further, the phase rotator 11 generates and outputs a signal obtained by performing phase error compensation on the analog-to-digital converted radio frame (received signal) output from the receiving unit 150 (step S1).

Then, when the power drop detection unit 2 detects a power fluctuation of the wireless frame (received signal) output from the phase rotator 11 to a degree that may cause malfunction of the equipment (step S2a), the carrier regeneration control switch 20 A power fluctuation notification signal is output to (step S3a). Alternatively, when the phase slip detection unit 3 detects a phase slip in the radio frame (received signal) output from the phase rotator 11 (step S2b), it outputs a slip notification signal to the carrier regeneration control switch 20 ( Step S3b).

Subsequently, the carrier regeneration control switch 20 to which the power fluctuation notification signal or the slip notification signal has been input is switched to connection with the hold output section 22, and outputs a regeneration hold signal to the loop filter 12 of the carrier regeneration section 10. (Step S4). Then, the loop filter 12 to which the reproduction hold signal is input stops the operation of removing the high frequency component of the phase error signal and the output operation, or extremely narrows the loop bandwidth of the PLL while controlling a predetermined value of the phase error signal. A frequency component removal process is performed (that is, the carrier regeneration loop in the carrier regeneration unit 10 is held; step S5).

Next, when the power drop detection unit 2 that outputs the power fluctuation notification signal detects that the power fluctuation has subsided and the power has returned to normal with respect to the radio frame (received signal) output from the phase rotator 11, ( Step S6a), a power recovery notification signal is output to the carrier regeneration control switch 20 (step S7a). Alternatively, when the phase slip detection unit 3 that outputs the slip notification signal detects that the phase state of the radio frame (received signal) output from the phase rotator 11 has returned to normal (step S6b), carrier regeneration control is performed. A phase recovery notification signal is output to the switch 20 (step S7b).

The carrier regeneration control switch 20 to which the power recovery notification signal or the phase recovery notification signal has been input is switched to connection with the specific range detection unit 23 and sends the specific range phase error signal to the loop filter 12 of the carrier recovery unit 10. supply (step S8). Then, the loop filter 12 removes high frequency components from the specific range phase error signal supplied from the carrier regeneration control switch 20 and outputs the signal. Further, the numerically controlled oscillator 13 generates an opposite phase sine wave signal or cosine wave signal based on the specific range phase error signal after high frequency component removal output from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerically controlled oscillator 13 on the analog-to-digital converted radio frame (received signal) output from the receiving unit 150. and resumed career rebirth. That is, the carrier reproducing unit 10 performs phase error compensation using the specific range phase error signal supplied from the specific range detecting unit 23 and restarts the carrier reproducing process (step S9).

Here, the all signal point detection unit 21 detects phase errors for all signal points S2 on the complex plane, so it is possible to detect phase errors with high accuracy. If unstable operation occurs, carrier reproduction in the carrier reproduction section 10 may become out of synchronization. On the other hand, the specific range detection unit 23 detects the phase error only for the signal points S2 on the far outer side or the inner side of the origin on the complex plane, so although the phase error detection accuracy is low, these signal points S2 Since the detectable range is wide, unstable operation is unlikely to occur even if a momentary abnormality occurs in the device, and it is possible to prevent and suppress a situation that leads to loss of synchronization of carrier regeneration in the carrier regeneration unit 10. Therefore, when restarting the carrier regeneration process in the carrier regeneration unit 10, by using a wider phase error detection range (detectable range) than normal as the initial phase error detection range (detectable range), the carrier regeneration process can be restarted. It becomes possible to smoothly perform the carrier reproduction process (in other words, the carrier reproduction synchronization process) at the beginning of restart when the reproduction process of the carrier tends to become unstable.

Subsequently, while the carrier regeneration control switch 20 is connected to the specific range detection section 23 and supplies the specific range phase error signal to the loop filter 12 (and by extension to the numerically controlled oscillator 13). , a predetermined period of time has elapsed since the power recovery notification signal output from the power drop detection unit 2 was input (except when the power recovery notification signal was not input), and the phase slip detection unit 3 After a predetermined period of time has passed since the output phase recovery notification signal was input (excluding cases where no phase recovery notification signal has been input), all signal point detection units 21 and connection, and supplies a full range phase error signal to the loop filter 12 of the carrier regeneration unit 10 (and by extension to the numerically controlled oscillator 13). Then, the loop filter 12 removes high frequency components from the full range phase error signal supplied from the carrier regeneration control switch 20 and outputs the signal. Further, the numerically controlled oscillator 13 generates an opposite phase sine wave signal or cosine wave signal based on the full range phase error signal after removing the high frequency component output from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13, on the analog-to-digital converted radio frame (received signal) output from the receiver 150. . That is, the carrier reproducing section 10 performs carrier reproducing processing using the full range phase error signal supplied from the all signal point detecting section 21 (step S10).

According to the radio receiving device 1 according to this embodiment, the parameters supplied to the carrier regeneration unit 10 are switched when power fluctuation or phase slip of the radio frame is detected. Malfunctions in carrier recovery (specifically, loss of synchronization) can be prevented, and carrier recovery section 10 can operate stably to achieve good demodulation performance (in other words, bit error rate). Become.

According to the radio receiving device 1 according to this embodiment, it is further possible to set a phase error having predetermined characteristics as a parameter by adjusting the phase error detection range on the complex plane, and the phase error can be set as a parameter by adjusting the phase error detection range on the complex plane. By controlling the carrier regeneration process by using the carrier regeneration process, it is possible to accurately prevent carrier regeneration malfunctions (specifically, loss of synchronization) due to instantaneous abnormalities in the equipment.

(Embodiment 2)
FIG. 10 is a functional block diagram showing a schematic configuration of a wireless receiving device 1 according to Embodiment 2 of the present invention. Note that FIG. 10 is based on a configuration such as the wireless communication device 101 in the wireless communication system 100 described above (see FIG. 1), and in consideration of showing the characteristic configuration of the present invention in an easy-to-understand manner, A part of the configuration of the wireless communication device 101 is omitted. Specifically, FIG. 10 shows a characteristic configuration applied to the configuration corresponding to the demodulation unit 160 between the reception unit 150 and the interface unit 110 of the wireless communication device 101 described above. It is shown as a wireless receiving device 1 as a mechanism related to.

The radio receiving device 1 according to this embodiment includes a power drop detection unit 2 that monitors the power of a received radio frame to determine whether there is a power fluctuation, and a power drop detection unit 2 that monitors the phase state of the radio frame to determine whether there is a phase slip. a phase slip detection unit 3 that determines the phase of the radio frame, and a numerically controlled oscillator 13 that outputs a phase rotation control signal to the phase rotator 11 that rotates the phase of the wireless frame; and a phase error signal to the numerically controlled oscillator 13. The carrier regeneration unit 10 includes a loop filter 12 that performs the following steps, and a carrier regeneration control switch 30 that can switch parameters to be supplied to the carrier regeneration unit 10. or when the phase slip detection section 3 detects a phase slip in the radio frame, the carrier regeneration control switch 30 switches the parameters to be supplied to the carrier regeneration section 10.

The radio receiving device 1 according to this embodiment is further configured such that the parameter is a loop filter coefficient that is supplied to the loop filter 12 and indicates the loop bandwidth of the PLL.

The radio receiving device 1 according to this embodiment is a circuit that performs carrier wave regeneration processing in digital radio transmission, and mainly includes a power drop detection section 2, a phase slip detection section 3, and a phase error detection section 7. It is configured as a mechanism including a carrier regeneration unit 10, and a carrier regeneration control switch 30.

The carrier regeneration unit 10 includes a phase rotator 11, a loop filter 12, and a numerically controlled oscillator 13. In the radio receiving apparatus 1, the phase rotator 11, symbol determination section 4, error calculation section 5, loop filter 12, and numerically controlled oscillator 13 constitute a carrier recovery loop that is PLL (abbreviation for Phase Locked Loop).

The phase rotator 11 has a function of rotating the phase of the analog-to-digital converted radio frame (received signal) output from the receiving section 150. Specifically, the phase rotator 11 performs phase rotation on the radio frame (received signal) based on a sine wave or cosine wave as a phase rotation control signal output from the numerically controlled oscillator 13. Phase error compensation is performed, and a phase error compensated signal is generated and output.

The loop filter 12 is a filter that removes high frequency components of the phase error signal output from the phase error detection section 7 according to a predetermined loop bandwidth. Specifically, the loop filter 12 receives the input of the phase error signal, receives the input of the loop filter coefficient output from the carrier regeneration control switch 30, and removes unnecessary high frequency components from the phase error signal. , outputs the phase error signal after high frequency component removal to the frequency control terminal of the numerically controlled oscillator 13.

The numerically controlled oscillator 13 (also referred to as "NCO (abbreviation for Numerical Controlled Oscillator)") generates a phase signal for performing phase error compensation by phase rotation based on the phase error signal output from the loop filter 12 after removing high frequency components. Equipped with a function to generate rotation control signals. Specifically, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal with an opposite phase based on the phase error signal after high frequency component removal output from the loop filter 12, and outputs the generated phase rotation control signal as a sine wave signal or a cosine wave signal. A sine wave signal and a cosine wave signal are output to the phase rotator 11. The phase rotation by the phase rotator 11 is controlled by the phase rotation control signal output from the numerically controlled oscillator 13.

The power drop detection unit 2 monitors the power (in other words, signal strength) of the radio frame (received signal) output from the phase rotator 11 of the carrier regeneration unit 10, and detects power that may cause equipment malfunction. Determine whether there is a change in

For example, when the modulation method used in the wireless communication system 100 is multi-value quadrature amplitude modulation (multi-value QAM; specifically, 16QAM, 64QAM, 256QAM), the determination of the presence or absence of power fluctuation can be made by: It is conceivable that this is performed based on the degree of constellation contraction with respect to the rectangular frame of multilevel QAM that corresponds to the case where the power is in a normal state (see FIGS. 3 and 4). In FIGS. 3 to 6, the horizontal axis is the I-axis of the complex plane, which corresponds to the in-phase component (Ich) after orthogonal detection processing, and the vertical axis is the Q-axis of the complex plane, which corresponds to the orthogonal Corresponds to the orthogonal component (Qch) after detection processing.

The determination of whether there is a power fluctuation may be made based on the average value of power over a predetermined length of time, or the number of consecutive symbols whose power is less than a predetermined value (specifically, For example, it may be performed based on the number of times (about 2 to 10 times).

When the power drop detection unit 2 detects a power fluctuation that may cause equipment malfunction, it sends a power fluctuation notification signal to the carrier regeneration control switch 30 to notify that a power fluctuation has occurred. Output. After detecting the power fluctuation, the power drop detection unit 2 also detects that the power fluctuation has subsided and the power has returned to normal, and then performs a power recovery function to notify that the power has returned to normal. A notification signal is output to the carrier regeneration control switch 30.

The phase slip detection section 3 monitors the phase state of the radio frame (received signal) output from the phase rotator 11 of the carrier regeneration section 10 and determines whether there is a phase slip. The determination of the presence or absence of a phase slip is made using a known pattern signal inserted into transmission data in the wireless communication device 101 on the transmitting side. For example, when the modulation method used in the wireless communication system 100 is multi-value quadrature amplitude modulation (multi-value QAM; specifically, 16QAM, 64QAM, 256QAM), the phase is It is conceivable to determine the presence or absence of a phase slip based on the proportion of signal points that protrude outside the rectangular frame of multilevel QAM in a normal state (see FIGS. 3 and 5). The ratio of the signal points used to determine whether or not there is a phase slip is not limited to a specific value, but may be set to an appropriate value after taking into consideration the characteristics of the communication equipment and modulation method, for example. will be set appropriately.

In the case of a phase slip, the phase state is not determined, and the distribution of signal points fluctuates by lagging behind or leading the rectangular frame of multilevel QAM when the phase is in a normal state. Signal points protrude into all areas around the rectangular frame of multilevel QAM (see FIG. 5). On the other hand, when the phase slip has subsided and the phase is stable, the distribution of signal points that protrude outside the rectangular frame of the multi-value QAM when the phase is in a normal state is the same as that of the multi-value QAM. It consistently lags or advances with respect to the rectangular frame, and is biased toward a specific area outside the rectangular frame of the multilevel QAM (see FIG. 6; in FIG. 6, area 1 is the phase Area 2 is an area where signal points protrude when the phase is rotating in a leading direction, and area 2 is an area where signal points protrude when the phase is rotating in a lag direction). Therefore, it may be possible to determine the presence or absence of a phase slip by taking into account the distribution of signal points that protrude outside the rectangular frame of multilevel QAM.

When the phase slip detection unit 3 detects a phase slip, it outputs a slip notification signal to the carrier regeneration control switch 30 to notify that a phase slip has occurred. After detecting a phase slip, the phase slip detection unit 3 also performs phase recovery to notify that the phase state has returned to normal when it detects that the phase slip has subsided and the phase state has returned to normal. A notification signal is output to the carrier regeneration control switch 30.

The symbol determination unit 4 performs symbol determination on the signal output from the phase rotator 11 of the carrier recovery unit 10, the phase of which has been rotated by the phase rotator 11 and phase error compensation has been performed.

The error calculation unit 5 calculates the phase error between the ideal symbol and the received symbol for the signal output from the symbol determination unit 4. Specifically, the error calculation section 5 is constituted by a subtracter.

The decoding unit 6 receives the signal output from the symbol determining unit 4, performs error correction decoding processing on the signal, and outputs transmission data generated by the decoding processing to the interface unit 110.

The phase error detection section 7 detects a phase error component in cooperation with the error calculation section 5, and generates a phase error signal (specifically, a phase error expressed as a voltage value) corresponding to the detected phase error component. signal) is output to the loop filter 12.

The carrier regeneration control switch 30 has a function of selecting one of the signals output from each of the normal coefficient output section 31 , the narrowband coefficient output section 32 , and the wideband coefficient output section 33 and supplying the selected signal to the loop filter 12 . Equipped with. The carrier regeneration control switch 30 is connected to one of the normal coefficient output section 31, the narrowband coefficient output section 32, and the wideband coefficient output section 33 according to the signals output from the power drop detection section 2 and the phase slip detection section 3. Switch.

In normal times, the carrier regeneration control switch 30 is connected to a normal coefficient output section 31 in which loop filter coefficients for normal times are stored in advance, and outputs signals to the loop filter 12 of the carrier regeneration section 10 from the carrier regeneration section 10. A loop filter coefficient (referred to as a "normal coefficient") indicating a normal loop bandwidth is supplied as a parameter.

In this case, the loop filter 12 uses the normal coefficients supplied from the normal coefficient output section 31 via the carrier regeneration control switch 30 to remove unnecessary high-frequency signals from the phase error signal output from the phase error detection section 7. The phase error signal after removing the high frequency component is output to the frequency control terminal of the numerically controlled oscillator 13. Then, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal of opposite phase based on the phase error signal after removing the high frequency component outputted from the loop filter 12 and outputs it as a phase rotation control signal, thereby rotating the phase. The receiver 11 performs phase rotation on the analog-to-digital converted radio frame (received signal) output from the receiver 150, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13. That is, the carrier reproducing section 10 performs carrier reproducing processing using the normal coefficients supplied from the normal coefficient output section 31.

The carrier regeneration control switch 30 is also connected to the normal coefficient output section 31 to supply the normal coefficient to the loop filter 12, and receives the power fluctuation notification signal output from the power drop detection section 2 as input. or when the slip notification signal output from the phase slip detection unit 3 is input, the connection is switched to the narrowband coefficient output unit 32 in which narrowband loop filter coefficients are stored in advance. , a loop filter coefficient (referred to as a "narrowband coefficient") indicating a narrowband loop bandwidth is supplied to the loop filter 12 of the carrier regeneration unit 10 as a parameter to be supplied to the carrier regeneration unit 10 .

Note that after the carrier regeneration control switch 30 is connected to the narrowband coefficient output section 32 and supplies the narrowband coefficient to the loop filter 12, the power fluctuation notification signal output from the power drop detection section 2 is further inputted. Or, if the slip notification signal output from the phase slip detection section 3 is further input, the carrier signal is sent to the loop filter 12 of the carrier regeneration section 10 while being connected to the narrowband coefficient output section 32. Narrowband coefficients are supplied as parameters to the reproduction section 10.

The narrowband coefficient is a signal that sets the loop bandwidth used in high frequency component removal processing by the loop filter 12 to be extremely narrow.

When the loop filter 12 is supplied with the narrowband coefficient output from the narrowband coefficient output section 32 via the carrier regeneration control switch 30, the loop filter 12 uses the narrowband coefficient to extremely narrow the loop bandwidth of the PLL. At the same time, processing is performed to remove a predetermined frequency component from the phase error signal output from the phase error detection section 7.

As the narrow band coefficient, a loop bandwidth value narrower than the normal coefficient is set. The loop bandwidth as a narrowband coefficient is not limited to a specific value, but the loop bandwidth used in the process of removing high frequency components by the loop filter 12 is made extremely narrow, and the PLL lock time (i.e., synchronization is set to a value that allows the carrier regeneration loop in the carrier regeneration unit 10 to be held in a pseudo manner.

The carrier regeneration control switch 30 is further connected to the narrowband coefficient output unit 32 and outputs the narrowband coefficient to the loop filter 12, and then receives the power recovery notification signal output from the power drop detection unit 2. Or, when the phase recovery notification signal output from the phase slip detection unit 3 is input, the connection is switched to the wideband coefficient output unit 33 in which the wideband loop filter coefficients are stored in advance, and carrier regeneration is performed. A loop filter coefficient (referred to as a "wideband coefficient") indicating a wideband loop bandwidth is supplied to the loop filter 12 of the section 10 as a parameter to be supplied to the carrier regeneration section 10 .

As the broadband coefficient, a loop bandwidth value wider than the normal coefficient is set. The loop bandwidth as a wideband coefficient is not limited to a specific value, but may increase due to fluctuations in the power of the radio frame (received signal) or detection errors that occur during normal operation before a phase slip is detected. It is set to an appropriate value, taking into consideration appropriate removal of phase errors caused by the noise and shortening of the PLL lock time (that is, the time until synchronization is achieved). Note that when a power recovery notification signal is output to the carrier regeneration control switch 30 after a power fluctuation notification signal is output from the power drop detection unit 2 (that is, when a power fluctuation occurs and the power is recovered). The wideband coefficient may be different depending on when the phase recovery notification signal is output after the phase slip detection unit 3 outputs the slip notification signal (that is, when the phase slip occurs and is recovered). Furthermore, the wideband coefficient may be settable by the user as appropriate.

The loop filter 12 removes a predetermined frequency component from the phase error signal output from the phase error detection section 7 by using the wideband coefficient supplied from the wideband coefficient output section 33 via the carrier regeneration control switch 30. The phase error signal after predetermined frequency component removal is output to the frequency control terminal of the numerically controlled oscillator 13. Then, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal of opposite phase based on the phase error signal after removing a predetermined frequency component outputted from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13, on the analog-to-digital converted radio frame (received signal) output from the reception unit 150. . That is, the carrier reproducing section 10 performs carrier reproducing processing using the wideband coefficients supplied from the wideband coefficient output section 33.

The carrier regeneration control switch 30 is connected to the wideband coefficient output unit 33 and supplies the wideband coefficient to the loop filter 12, and after the power recovery notification signal output from the power drop detection unit 2 is input. A predetermined time has elapsed (excluding cases where no power recovery notification signal has been input), and a predetermined time has elapsed since the phase recovery notification signal output from the phase slip detection unit 3 was input ( However, when the phase recovery notification signal is not input (except when the phase recovery notification signal is not input), the connection is switched to the normal coefficient output section 31 for carrier regeneration during normal operation, and the connection is switched to the normal coefficient output section 31, and the connection is , the normal coefficient is supplied as a parameter to the carrier reproducing unit 10.

Note that the wideband coefficient output unit 33 outputs and supplies a loop filter coefficient indicating a wideband loop bandwidth as a wideband coefficient to the carrier regeneration control switch 30 and further to the loop filter 12 at a predetermined time. The output/supply may be performed while gradually decreasing the broadband coefficient over time until it becomes the same as the loop filter coefficient indicating the normal loop bandwidth as the normal time coefficient.

Further, the carrier regeneration control switch 30 is connected to the wideband coefficient output section 33 and supplies the wideband coefficient to the loop filter 12, and the power fluctuation notification signal output from the power drop detection section 2 is inputted thereto. or when the slip notification signal output from the phase slip detection section 3 is input, the connection is switched to the narrowband coefficient output section 32 and the signal is output to the loop filter 12 of the carrier regeneration section 10. Then, the narrowband coefficient is output as a parameter to be supplied to the carrier reproducing section 10.

Next, the operation and effects of the radio receiving device 1 having such a configuration will be described with reference to FIG. 11 as well.

First, a wireless frame transmitted from another wireless communication device 101 (the wireless communication device 101 on the transmitting side in this communication) via the wireless line 103 is sent to the wireless communication device 101 (the wireless communication device 101 on the receiving side in this communication). ) is being received. At this time, the carrier regeneration control switch 30 of the wireless communication device 101 on the receiving side connects with the normal coefficient output section 31 to supply the normal time coefficient to the loop filter 12 of the carrier regeneration section 10, and , the loop filter 12 uses the normal coefficient supplied from the carrier regeneration control switch 30 to remove high frequency components from the phase error signal output from the phase error detection section 7 and outputs the result. Further, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal with an opposite phase based on the phase error signal after high frequency component removal outputted from the loop filter 12, and outputs it as a phase rotation control signal, thereby rotating the phase. The receiver 11 performs phase rotation on the analog-to-digital converted radio frame (received signal) output from the receiver 150, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13. . That is, the carrier reproducing unit 10 performs carrier reproducing processing using the normal coefficients supplied from the normal coefficient output unit 31 (step S0).

When the wireless communication device 101 on the receiving side receives a wireless frame transmitted from the wireless communication device 101 on the transmitting side via the wireless line 103, the receiving unit 150 of the wireless communication device 101 on the receiving side performs frequency conversion and analog-to-analog conversion. Outputs digitally converted wireless frames (received signals). Further, the phase rotator 11 generates and outputs a signal obtained by performing phase error compensation on the analog-to-digital converted radio frame (received signal) output from the receiving unit 150 (step S1).

Then, when the power drop detection unit 2 detects a power fluctuation of the wireless frame (received signal) output from the phase rotator 11 to a degree that may cause malfunction of the equipment (step S2a), the carrier regeneration control switch 30 A power fluctuation notification signal is output to (step S3a). Alternatively, when the phase slip detection unit 3 detects a phase slip in the radio frame (received signal) output from the phase rotator 11 (step S2b), it outputs a slip notification signal to the carrier regeneration control switch 30 ( Step S3b).

Subsequently, the carrier regeneration control switch 30 to which the power fluctuation notification signal or the slip notification signal is input is switched to the connection with the narrowband coefficient output section 32, and outputs the narrowband coefficient to the loop filter 12 of the carrier regeneration section 10. is supplied (step S4). Then, the loop filter 12 to which the narrowband coefficients are supplied uses the narrowband coefficients to extremely narrow the loop bandwidth of the PLL, and outputs a predetermined amount of the phase error signal output from the phase error detection section 7. Performs processing to remove frequency components. In this case, since the loop bandwidth used in the high frequency component removal process by the loop filter 12 is extremely narrow, the PLL lock time (that is, the time until synchronization is achieved) becomes long, and the carrier recovery loop in the carrier recovery unit 10 becomes It is held in a pseudo manner (step S5).

Next, when the power drop detection unit 2 that outputs the power fluctuation notification signal detects that the power fluctuation has subsided and the power has returned to normal with respect to the radio frame (received signal) output from the phase rotator 11, ( Step S6a), a power recovery notification signal is output to the carrier regeneration control switch 30 (step S7a). Alternatively, when the phase slip detection unit 3 that outputs the slip notification signal detects that the phase state of the radio frame (received signal) output from the phase rotator 11 has returned to normal (step S6b), carrier regeneration control is performed. A phase recovery notification signal is output to the switch 30 (step S7b).

The carrier regeneration control switch 30 to which the power recovery notification signal or the phase recovery notification signal is input is switched to the connection with the wideband coefficient output section 33, and supplies the wideband coefficient to the loop filter 12 of the carrier regeneration section 10 ( Step S8). Then, the loop filter 12 uses the broadband coefficients supplied from the carrier regeneration control switch 30 to remove a predetermined frequency component from the phase error signal output from the phase error detection section 7 and outputs the removed signal. Further, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal of opposite phase based on the phase error signal after removing a predetermined frequency component output from the loop filter 12, and outputs it as a phase rotation control signal, The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerically controlled oscillator 13 on the analog-to-digital converted radio frame (received signal) output from the receiving unit 150. and resumed career rebirth. That is, the carrier regeneration unit 10 performs phase error compensation using the wideband coefficients supplied from the wideband coefficient output unit 33 and restarts the carrier regeneration process (step S9).

Here, the normal coefficients output from the normal coefficient output section 31 are the PLL lock time (in other words, the followability of the carrier recovery loop with respect to phase changes) and the phase noise value (also called "C/N value"). 7 between the If this occurs, the lock time of the PLL becomes longer, and the carrier recovery loop may not be able to sufficiently follow the change in phase, resulting in a significant drop in the phase noise value. On the other hand, in the wideband coefficient outputted from the wideband coefficient output section 33, a loop bandwidth value wider than that of the normal coefficient is set, so that the high frequency component of the phase error signal outputted from the phase error detection section 7 Although the phase noise value decreases slightly because the phase noise cannot be removed, the lock time of the PLL is shortened and the ability to follow phase changes is improved, so unstable operation is less likely to occur even if a momentary abnormality occurs in the equipment. , the lock time of the PLL is shortened, and the carrier regeneration loop can sufficiently follow the change in phase. Therefore, when restarting the carrier reproducing process in the carrier reproducing unit 10, using a wider loop bandwidth than usual as the loop bandwidth at the beginning of the restart, the carrier reproducing process tends to become unstable. It is possible to smoothly perform carrier reproduction processing (in other words, carrier reproduction synchronization processing) at the beginning.

Subsequently, while the carrier regeneration control switch 30 is connected to the wideband coefficient output section 33 and supplies the wideband coefficient to the loop filter 12, the power recovery notification signal output from the power drop detection section 2 is input. A predetermined time has elapsed since the power recovery notification signal was input (except when the power recovery notification signal has not been input), and a predetermined time has passed since the phase recovery notification signal output from the phase slip detection section 3 was input. has passed (except when the phase recovery notification signal is not input), the connection is switched to the normal coefficient output section 31 for carrier regeneration during normal operation, and the connection is switched to the loop filter 12 of the carrier regeneration section 10. supply the normal coefficient. Then, the loop filter 12 uses the normal coefficient supplied from the carrier regeneration control switch 30 to remove high frequency components from the phase error signal output from the phase error detection section 7 and outputs the result. Further, the numerically controlled oscillator 13 generates a sine wave signal or a cosine wave signal with an opposite phase based on the phase error signal after high frequency component removal outputted from the loop filter 12, and outputs it as a phase rotation control signal, thereby rotating the phase. The receiver 11 performs phase rotation on the analog-to-digital converted radio frame (received signal) output from the receiver 150, which is controlled by the phase rotation control signal output from the numerically controlled oscillator 13. That is, the carrier reproducing unit 10 performs carrier reproducing processing using the normal coefficients supplied from the normal coefficient output unit 31 (step S10).

According to the radio receiving device 1 according to this embodiment, the parameters supplied to the carrier regeneration unit 10 are switched when power fluctuation or phase slip of the radio frame is detected. Malfunctions in carrier recovery (specifically, loss of synchronization) can be prevented, and carrier recovery section 10 can operate stably to achieve good demodulation performance (in other words, bit error rate). Become.

According to the radio receiving device 1 according to this embodiment, a loop filter coefficient having predetermined characteristics can be further set as a parameter by adjusting the loop bandwidth of the PLL, and the loop filter coefficient can be set as a parameter. By controlling the carrier regeneration process using the above, it becomes possible to accurately prevent carrier regeneration malfunctions (specifically, loss of synchronization) due to instantaneous abnormalities in the equipment.

Although the embodiments of this invention have been described above, the specific configuration is not limited to the above embodiments, and even if there are changes in the design within the scope of the gist of this invention, Included in invention. Specifically, in the above embodiment, the wireless communication device 101 shown in FIG. 1 is cited as a base configuration to which the wireless receiving device 1 according to the present invention is applied, but the wireless communication device 101 shown in FIG. The configuration is not limited to the wireless communication device 101 shown in FIG. 1, and the configuration of the wireless receiving device 1 as described above can be applied as a mechanism related to reception (in other words, Any wireless communication device (which can be incorporated into the system) may be used. Specifically, for example, any wireless communication device may have any configuration as long as it includes a configuration corresponding to the carrier reproducing unit 10 in the above embodiment.

Further, although the above embodiment includes both the power drop detection section 2 and the phase slip detection section 3, providing these two is not an essential configuration in the present invention, and the power drop detection section 2 and a phase slip detection section 3.

1 Radio receiving device 2 Power drop detection section 3 Phase slip detection section 4 Symbol determination section 5 Error calculation section 6 Decoding section 7 Phase error detection section 10 Carrier regeneration section 11 Phase rotator 12 Loop filter 13 Numerical control oscillator 20 Carrier regeneration control switch (Embodiment 1)
21 All signal point detection section 22 Hold output section 23 Specific range detection section 30 Carrier regeneration control switch (Embodiment 2)
31 Normal coefficient output section 32 Narrowband coefficient output section 33 Wideband coefficient output section 100 Wireless communication system 101 Wireless communication device 102 Antenna 103 Wireless line 110 Interface section 111 Data line termination device 120 Modulation section 130 Transmission section 140 Brancher 150 Receiving section 160 Demodulator

Claims (4)

a power drop detection unit that monitors the power of the received wireless frame and determines whether there is a fluctuation in the power;
a phase slip detection unit that monitors the phase state of the wireless frame and determines whether there is a phase slip;
a carrier regeneration unit including a numerically controlled oscillator that outputs a phase rotation control signal to a phase rotator that rotates the phase of the radio frame, and a loop filter that outputs a phase error signal to the numerically controlled oscillator;
a switch capable of switching parameters supplied to the carrier regeneration unit,
When the power drop detection section detects a variation in the power of the radio frame, or when the phase slip detection section detects the phase slip of the radio frame,
the switch switches the parameter supplied to the carrier regeneration unit;
A wireless receiving device characterized by: The parameter is a phase error detected with a phase error detection range on a complex plane set to a predetermined range, which is supplied to the loop filter.
The radio receiving device according to claim 1, characterized in that: The parameter is a loop filter coefficient indicating a loop bandwidth of a PLL, which is supplied to the loop filter.
The radio receiving device according to claim 1, characterized in that: the modulation method of the radio frame is quadrature amplitude modulation;
The wireless receiving device according to any one of claims 1 to 3.

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