JP2021114664A - Radio receiver - Google Patents

Abstract

To provide a radio receiver capable of stably operating a carrier regeneration loop by controlling the state of the carrier regeneration loop, based on a detection result of instantaneous variation of level in a series of amplifiers relating to transmission and reception or a slip of a carrier phase or a local phase.SOLUTION: A radio receiver includes: a power decrease detection part 2 for determining existence of power variation of a radio frame; a phase slip detection part 3 for determining existence of phase slip of the radio frame; a carrier regeneration part 10 including a numerical control oscillator 13 for outputting a phase rotation control signal to a phase rotator 11 and a loop filter 12 for outputting a phase error signal to the numerical control oscillator; and a carrier regeneration control switch 20 capable of switching over a parameter to be supplied to the carrier regeneration part 10. The carrier regeneration control switch 20 switches over the parameter supplied to the carrier regeneration part 10 if the power decrease detection part 2 detects power variation of the radio frame or the phase slip detection part 3 detects a phase slip of the radio frame.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless receiving device, and more particularly to a wireless receiving device as a mechanism associated with reception in a wireless communication device.

As a technique related to a wireless communication device, for example, a main signal modulated by an arbitrary multi-value modulation method and an auxiliary signal modulated by a phase number equal to or less than the number of phases of the multi-value modulation of this main signal. Is time-divided and multiplexed, and auxiliary signals are placed on multiple consecutive symbols at the beginning of each frame, followed by the main signal, and the auxiliary signals are distributed in the main signal at regular intervals. The phase error of the frequency conversion signal generated by inputting a digitally modulated wave and frequency-converting the digitally modulated wave using the reproduction carrier signal is detected, and the frequency and phase of the reproduction carrier are set so as to reduce the phase error. In the carrier reproduction circuit that performs carrier reproduction by control, from the frame detection means for detecting the frame head of the digitally modulated wave and the auxiliary signals of a plurality of continuous symbols at the frame head based on the frame detection timing detected by this means. The first phase error detecting means for obtaining the first phase error of the reproduction carrier and the second phase of the reproduction carrier from the auxiliary signals distributed in the main signal based on the frame detection timing detected by the frame detecting means. A second phase error detecting means for obtaining an error is provided, the frequency of the reproduction carrier is pulled in by the first phase error obtained by the first phase error detecting means, and the second phase error detecting means obtains the frequency. It is known that the phase of the reproduction carrier is pulled in by the phase error of 2 (Patent Document 1).

Japanese Patent No. 3926945

By the way, in a wireless communication device, the level of an amplifier system (for example, a preamplifier or a power amplifier) related to transmission / reception may drop momentarily due to fluctuations or vibration of the power supply of the device, or frequency conversion may occur due to the vibration of the device. Carrier phase / local phase may momentarily slip (in other words, rotate). However, in the conventional wireless communication device, the purpose of the carrier reproduction method is to perform a stable initial pull-in at the time of startup, and the stable operation is not guaranteed against a momentary abnormality of the device. For this reason, in the conventional wireless communication device, the level of the amplifier system related to transmission / reception as described above may drop momentarily, or the carrier phase / local phase for frequency conversion may slip momentarily. There is a problem that it cannot be dealt with.

Therefore, the present invention controls the state of the carrier reproduction loop based on the instantaneous fluctuation of the amplifier system level related to transmission / reception and the detection result of the carrier phase / local phase slip to operate the carrier reproduction loop stably. It is an object of the present invention to provide a wireless receiver capable of providing a capable wireless receiver.

In order to solve the above problem, the invention according to claim 1 has a power reduction detection unit that monitors the power of the received wireless frame to determine whether or not the power fluctuates, and monitors the phase state of the wireless frame. A numerically controlled oscillator and the numerical value that have at least one of a phase slip detecting unit for determining the presence or absence of phase slip and output a phase rotation control signal to a phase rotator that rotates the phase of the wireless frame. It has a carrier reproduction unit including a loop filter that outputs a phase error signal to a control oscillator, and a switch that can switch parameters supplied to the carrier reproduction unit, and the power reduction detection unit is the wireless frame. When a fluctuation in power is detected, or when the phase slip detection unit detects the phase slip of the wireless frame, the switch switches the parameter supplied to the carrier reproduction unit. It is a wireless receiver.

According to the second aspect of the present invention, in the wireless receiving device according to the first aspect, the parameter is supplied to the loop filter, and the phase error detection range on the complex plane is set to a predetermined range for detection. It is characterized in that it is a phase error.

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 the loop bandwidth of the PLL supplied to the loop filter. do.

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

According to the first aspect of the present invention, when the fluctuation of the power of the wireless frame or the phase slip is detected, the parameter supplied to the carrier reproduction unit is switched, so that the carrier reproduction malfunctions due to an instantaneous abnormality of the device. (Specifically, out-of-synchronization) can be prevented, and the carrier reproduction unit can be operated stably to realize good demodulation performance (in other words, a bit error rate).

According to the invention according to claim 2, a phase error having a predetermined characteristic 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 for the carrier. By controlling the reproduction process, it is possible to accurately prevent a carrier reproduction malfunction (specifically, out of synchronization) due to an instantaneous abnormality of the device.

According to the third aspect of the present invention, a loop filter coefficient having a predetermined characteristic can be set as a parameter by adjusting the loop bandwidth of the PLL, and carrier regeneration is performed using the loop filter coefficient as a parameter. By controlling the processing, it is possible to accurately prevent the carrier reproduction malfunction (specifically, out of synchronization) due to an instantaneous abnormality of the device.

According to the invention of claim 4, the above-mentioned effect can be obtained in wireless communication performed by using the quadrature phase amplitude modulation method.

It is a figure which shows the schematic structure of the wireless communication system in embodiment of this invention. It is a functional block diagram which shows the schematic structure of the wireless receiver device which concerns on Embodiment 1 of this invention. It is a figure which shows the example of the constellation of the wireless frame (received signal) output from a receiving part, and is the figure explaining the state which the power and phase of a wireless frame (received signal) are normal. It is a figure explaining the state which the power of the radio frame is low about the constellation of FIG. It is a figure explaining the state which the phase of a radio frame is slipping about the constellation of FIG. It is a figure explaining the state which the phase of a radio frame is stable about the constellation of FIG. It is a conceptual diagram which shows the detection method of all the signal point detection part of the wireless receiver of FIG. It is a conceptual diagram which shows the detection method of the specific range detection part of the wireless receiver of FIG. It is a figure explaining the operation of the wireless receiver of FIG. It is a functional block diagram which shows the schematic structure of the wireless receiver device which concerns on Embodiment 2 of this invention. It is a figure explaining the operation of the wireless receiver device of FIG.

Hereinafter, the present invention will be described based on the illustrated embodiment. In the following, the characteristic configuration of the present invention will be described, and the description of the same mechanism as the conventional one when performing wireless communication will be omitted.

FIG. 1 is a diagram showing a schematic configuration of a wireless communication system 100 according to an embodiment of the present invention. FIG. 1 shows the schematic configuration of the wireless communication system 100 (upper side of FIG. 1) and shows the functional blocks of the schematic configuration of the wireless communication device 101 arranged in each of the transmitting and receiving stations of wireless communication (lower side of FIG. 1). ).

A wireless communication device 101 and an antenna 102 are arranged at each of the transmission / reception stations for wireless communication constituting 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 the 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 modulation unit 120 and a transmission unit 130 for transmission, a reception unit 150 and a demodulation unit 160 for reception, and an interface unit 110 (see the lower side of FIG. 1). ..

Here, the wireless communication device 101 is a device that includes a transmission mechanism and a reception mechanism to perform transmission / reception. However, in the following description, processing related to transmission is performed using the transmission mechanism. The wireless communication device 101 in the case of performing the process is referred to as a "transmitting side", and the wireless communication device 101 in the case of performing the processing related to the reception using the receiving mechanism is referred to as the "receiving side".

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

The modulation unit 120 receives the input of the transmission data output from the interface unit 110, inserts a frame synchronization signal into the transmission data to generate a wireless frame (transmission signal), and further inserts the frame synchronization signal into the wireless frame (transmission signal). A carrier signal of a predetermined frequency is superimposed, digitally modulated, and output. The modulation unit 120 superimposes a carrier signal having a frequency of, for example, about 400 MHz on the wireless frame to perform digital modulation. The modulation method used in the wireless communication system 100 is not limited to a specific method, but for example, quadrature amplitude modulation (QAM: an abbreviation for Quadrature Amplitude Modulation) is used.

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

The transmission unit 130 also passes the frequency-converted wireless 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 the signal.

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

Further, the wireless frame 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 is the wireless communication device (in other words, the receiving side in this communication). When transmitted as a radio wave to the antenna 102 of the 101, the antenna 102 converts the received wireless frame into an electric signal (received wave signal) and outputs the signal.

The radio frame (received wave signal) converted into an electric signal, which is output from the antenna 102, is guided to the receiving unit 150 via the demultiplexer 140.

The receiving unit 150 receives an input of a radio frame (received wave signal), passes the radio frame (received wave signal) through a reception filter that allows only signals in a predetermined frequency band to pass, and amplifies the radio frame (received wave signal) with a preamplifier. It is converted into a signal having a frequency lower than the high frequency (for example, about 10 GHz) (for example, about 400 MHz) by a local oscillator and a mixer.

The receiving unit 150 further amplifies the frequency-converted signal with a power amplifier and analog-digitally converts it with an A / D converter to output a digital signal (radio frame (received signal)).

In the receiving unit 150, the radio frame (received wave signal) is subjected to orthogonal detection processing, and the baseband signal of the in-phase component (Ich) and the baseband signal of the orthogonal component (Qch) whose phases are orthogonal to each other are displayed. Although it is generated, in the following explanation, unless it is necessary to pay attention to each of the in-phase component and the orthogonal component separately, the in-phase component and the orthogonal component will be explained as contents common to both without any particular distinction. Further, in the drawing, the signal of the in-phase component and the signal of the orthogonal component are represented by one signal line.

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

In the wireless communication system 100 described above, in the local oscillator of the transmitting unit 130 and the receiving unit 150, a momentary slip (in other words, rotation) of the carrier phase / local phase for frequency conversion occurs due to the vibration of the device. Problems arise. In the wireless communication system 100 described above, the power amplifier of the transmitting unit 130 and the preamplifier and power amplifier of the receiving unit 150 are at a momentary level due to fluctuations (also referred to as “instantaneous interruption”) or vibration of the power supply of the device. The problem arises that the constellation shrinks due to the drop.

Therefore, the wireless receiver 1 according to the present invention detects instantaneous fluctuation of electric power and slip of carrier phase / local phase (in other words, rotation), and controls the operation related to carrier reproduction based on the detection result. It is equipped with a mechanism to prevent malfunction of carrier regeneration (specifically, out of synchronization) due to vibration of equipment or instantaneous fluctuation of electric power, and to stably perform processing related to carrier regeneration.

(Embodiment 1)
FIG. 2 is a functional block diagram showing a schematic configuration of the wireless receiver 1 according to the first embodiment of the present invention. Note that FIG. 2 is based on the configuration (see FIG. 1) like the wireless communication device 101 in the wireless communication system 100 described above, 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. 2 specifically receives a characteristic configuration applied to a configuration corresponding to a 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 receiver 1 as a mechanism associated with.

The wireless receiving device 1 according to this embodiment includes a power drop detection unit 2 that monitors the power of the received wireless frame to determine the presence or absence of power fluctuation, and a phase state of the wireless frame that monitors the presence or absence of phase slip. It has a phase slip detection unit 3 for determining the above, and outputs a phase error signal to the numerical control oscillator 13 and the numerical control oscillator 13 which output the phase rotation control signal to the phase rotor 11 which rotates the phase of the wireless frame. The carrier regeneration unit 10 including the loop filter 12 and the carrier regeneration control switch 20 capable of switching the parameters supplied to the carrier regeneration unit 10 are provided, and the power reduction detection unit 2 detects fluctuations in the power of the wireless frame. When the phase slip detection unit 3 detects the phase slip of the wireless frame, the carrier regeneration control switch 20 switches the parameter supplied to the carrier regeneration unit 10.

The wireless receiver 1 according to this embodiment further has the above parameter supplied to the loop filter 12 and is a phase error detected by setting the phase error detection range on the complex plane to a predetermined range. , And so on.

The wireless receiver 1 according to this embodiment is a circuit that performs carrier wave regeneration processing in digital wireless transmission, and mainly includes a power reduction detection unit 2, a phase slip detection unit 3, and a carrier reproduction unit 10. , The mechanism including the 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 receiver 1, the phase rotating unit 11, the symbol determination unit 4, the error calculation unit 5, the loop filter 12, and the numerically controlled oscillator 13 form a carrier regeneration loop which is a PLL (abbreviation of Phase Locked Loop).

The phase rotator 11 has a function of rotating the phase of the analog-to-digital converted wireless frame (received signal) output from the receiving unit 150. Specifically, the phase rotator 11 performs phase rotation on the wireless frame (received signal) based on a sine wave or a cosine wave as a phase rotation control signal output from the numerical control oscillator 13. Phase error compensation is performed, and a signal with phase error compensation 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 an unnecessary high frequency component from the phase error signal, and removes the high frequency component. The phase error signal is output to the frequency control terminal of the numerical control oscillator 13.

The numerically controlled oscillator 13 (also called "NCO (abbreviation of Numerical Controlled Oscillator)") is a phase for performing phase error compensation by phase rotation based on the phase error signal after removing the high frequency component output from the loop filter 12. It has a function to generate a rotation control signal. Specifically, the numerical control oscillator 13 generates an antiphase sine wave signal or a chord wave signal based on the phase error signal after removing the high frequency component output from the loop filter 12, and uses the generated phase rotation control signal as the generated phase rotation control signal. The sine wave signal and the cosine wave signal of the above are output to the phase rotator 11. The phase rotation by the phase rotor 11 is controlled by the phase rotation control signal output from the numerically controlled oscillator 13.

The power reduction detection unit 2 monitors the power (in other words, signal strength) of the wireless frame (received signal) output from the phase rotator 11 of the carrier reproduction unit 10, and has a power sufficient to cause a malfunction of the device. Judge whether or not there is a change in.

The presence or absence of power fluctuation is determined, 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). It is conceivable that this is done based on the degree of contraction of the constellation with respect to the corresponding multi-level QAM rectangular frame when 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 and corresponds to the in-phase component (Ich) after the orthogonal detection process, and the vertical axis is the Q-axis of the complex plane and is orthogonal. Corresponds to the orthogonal component (Qch) after the detection process.

The presence or absence of fluctuations in electric power may be determined based on the average value of electric power over a predetermined time length, or the number of consecutive symbols in which electric power is less than a predetermined value (specifically, For example, it may be performed based on (about 2 to 10 times).

When the power reduction detection unit 2 detects a power fluctuation that may cause a malfunction of the device, the power fluctuation detection unit 2 sends a power fluctuation notification signal to the carrier regeneration control switch 20 to notify that the power fluctuation has occurred. Output. When the power reduction detection unit 2 detects that the power fluctuation has subsided and the power has returned to normal after detecting the power fluctuation, the power recovery for notifying that the power has returned to normal A notification signal is output to the carrier reproduction control switch 20.

The phase slip detection unit 3 monitors the phase state of the radio frame (received signal) output from the phase rotator 11 of the carrier reproduction unit 10 and determines the presence or absence of the phase slip. The presence or absence of phase slip is determined by using a known pattern signal inserted into the 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 rotated to change the phase. It is conceivable to determine the presence or absence of phase slip based on the proportion of signal points protruding outside the rectangular frame of the multi-level QAM in the normal state (see FIGS. 3 and 5). The ratio of the signal points for determining whether or not the phase slip is not limited to a specific value, and is an appropriate value after considering, for example, the characteristics of the communication device and the modulation method. Is set as appropriate.

In the case of phase slip, the phase state is not determined, and the distribution of signal points fluctuates with respect to the rectangular frame of the multi-level QAM when the phase is normal, and the above-mentioned Signal points extend beyond any area around the rectangular frame of the multi-level QAM (see FIG. 5). On the other hand, when the phase slip has subsided and the phase is stable, the distribution of the signal points protruding outside the rectangular frame of the multi-level QAM when the phase is normal is the distribution of the multi-level QAM. It is constant whether it lags or advances with respect to the rectangular frame, and is biased to a specific area outside the rectangular frame of the multi-value QAM (see FIG. 6; in FIG. 6, the area 1 is phased. Is the area where the signal point protrudes when rotating in the forward direction, and area 2 is the area where the signal point protrudes when the phase is rotating in the lagging direction). Therefore, it is conceivable to determine the presence or absence of phase slip in consideration of the distribution of signal points protruding outside the rectangular frame of the multi-level QAM.

When the phase slip detection unit 3 detects the phase slip, the phase slip detection unit 3 outputs a slip notification signal for notifying that the phase slip has occurred to the carrier regeneration control switch 20. When the phase slip detection unit 3 detects that the phase slip has subsided and the phase state has returned to normal after detecting the phase slip, the phase retrieval unit 3 is for notifying that the phase state has returned to normal. A notification signal is output to the carrier reproduction control switch 20.

The symbol determination unit 4 performs symbol determination on a signal output from the phase rotator 11 of the carrier reproduction unit 10 whose phase is rotated by the phase rotator 11 and whose phase error is compensated.

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 unit 5 is composed of a subtractor.

The decoding unit 6 receives the input of the signal output from the symbol determination unit 4, performs an error correction decoding process on the signal, and outputs the transmission data generated by the decoding process 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 unit 21, the hold output unit 22, and the specific range detection unit 23 and supplying the signal to the loop filter 12. Be prepared. The carrier regeneration control switch 20 connects to any of the all signal point detection unit 21, the hold output unit 22, and the specific range detection unit 23 according to the signals output from the power reduction detection unit 2 and the phase slip detection unit 3. Switch.

Normally, the carrier regeneration control switch 20 is connected to the all signal point detection unit 21 that detects a phase error for all signal points on the complex plane, and is connected to the loop filter 12 of the carrier regeneration unit 10 (by extension, the carrier regeneration control switch 20). , For the numerically controlled oscillator 13), as a parameter to be supplied to the carrier reproduction unit 10, the phase error for all signal points (the signal expressing the phase error for all signal points by the voltage value is the "full range phase error signal". To supply).

In this case, the loop filter 12 removes unnecessary high-frequency components from the full-range phase error signal supplied from the full-range phase error signal 21 via the carrier regeneration control switch 20, and removes the high-frequency components, and then the full-range phase error. The signal is output to the frequency control terminal of the numerically controlled oscillator 13. Then, the numerical control oscillator 13 generates an antiphase sine wave signal or a 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 the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. .. That is, the carrier reproduction unit 10 performs carrier reproduction processing using the full range phase error signal supplied from the all signal point detection unit 21.

As shown in FIG. 7, the all signal point detection unit 21 has a predetermined range (“phase error detection range W1” centered on the reference point S1 corresponding to each of the signal points S2 for all signal points S2 on the complex plane. It has a function to detect the phase error in (called). 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 the complex plane, and a quadrangle centered on each reference point S1 is divided vertically and horizontally at equal intervals between the reference points S1. The phase error detection range W1 is densely set (see FIG. 7). Then, the all signal point detection unit 21 calculates the phase error of how much the signal point S2 deviates from the reference point S1 in the advance direction or the lag direction in each phase error detection range W1. To detect. 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 narrower as the value increases. In that case, unstable operation may occur due to a momentary abnormality of the device such as power fluctuation or phase slip, which may lead to out-of-synchronization of carrier reproduction.

The carrier regeneration control switch 20 is also connected to the full signal point detection unit 21 to supply a full range phase error signal to the loop filter 12 (to the numerical control oscillator 13). , When the power fluctuation notification signal output from the power reduction detection unit 2 is input, or when the slip notification signal output from the phase slip detection unit 3 is input, the reproduction hold signal is stored in advance. The connection with the output unit 22 is switched, and a reproduction hold signal is output to the loop filter 12 of the carrier reproduction unit 10 as a parameter to be supplied to the carrier reproduction unit 10.

The carrier reproduction control switch 20 may be connected to the hold output unit 22 to output a reproduction hold signal to the loop filter 12, and then a power fluctuation notification signal output from the power reduction detection unit 2 may be further input. Alternatively, when the slip notification signal output from the phase slip detection unit 3 is further input, the loop filter 12 of the carrier reproduction unit 10 is connected to the carrier reproduction unit 10 while being connected to the hold output unit 22. The playback hold signal is output as a parameter to be supplied.

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

When the reproduction hold signal output from the hold output unit 22 is input via the carrier reproduction control switch 20, the loop filter 12 stops the operation of removing the high frequency component of the phase error signal and the output operation, or the PLL. While extremely narrowing the loop bandwidth of the above, the process of removing a predetermined frequency component of the phase error signal is performed. By setting the loop bandwidth of the PLL used in the removal processing of the high frequency component by the loop filter 12 to be extremely narrow, the lock time of the PLL (that is, the time until synchronization is achieved) is lengthened, and the carrier reproduction unit 10 The carrier reproduction loop in the above can be held in a pseudo manner.

When the carrier regeneration control switch 20 is further connected to the hold output unit 22 to output a regeneration hold signal to the loop filter 12, and then a power recovery notification signal output from the power reduction detection unit 2 is input, the carrier regeneration control switch 20 is connected. Alternatively, when the phase recovery notification signal output from the phase slip detection unit 3 is input, the connection with the specific range detection unit 23 that detects the phase error for the signal points located within the specific range on the complex plane is established. After switching, the phase with respect to the signal point located within a specific range as a parameter supplied to the carrier reproduction unit 10 with respect to the loop filter 12 of the carrier reproduction unit 10 (to the numerical control oscillator 13). An error (a signal in which the phase error of a signal point located within a specific range is expressed by a voltage value is called a "specific range phase error signal") is supplied.

As shown in FIG. 8, the specific range detection unit 23 is a signal point S2 located outside the region of the first radius C1 centered on the origin on the complex plane (that is, the intersection of the I axis and the Q axis). And, the phase shift error is detected for at least one signal point S2 of the signal point S2 located in the region of the second radius C2 smaller than the first radius C1 centered on the origin on the complex plane. It has a function to do.

That is, on a complex plane in which a plurality of reference points S1 are arranged vertically and horizontally at equal intervals, outside the region of the first radius C1 centered on the origin, the reference points S1 and the corresponding signal points S2 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 arranged vertically and horizontally at equal intervals, the reference points S1 and the reference points S1 and the like are within the region of the second radius C2 (note that C2 << C1) centered on the origin. 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 detection targets, and the sizes of the radius C1 and the radius C2 are set so that unstable operation does not occur.

In such a region where the reference point S1 and the signal point S2 are small, the phase error detection range (in other words, the detectable range) is wide, so that the instability is caused by a momentary abnormality of the device such as power fluctuation or phase slip. It is possible to prevent / suppress a situation in which operation is unlikely to occur and the carrier reproduction is out of phase. That is, by determining the deviation direction of the signal point S2 with respect to the reference line L having an inclination angle of 45 degrees, it is possible to reliably detect whether the phase is rotating in the direction of advance or the phase is rotating in the direction of delay. In addition, the phase error amount can be reliably detected by calculating the deviation amount / rotation amount of the signal point S2 from the reference line L. On the other hand, since the phase error is detected only at a small number of signal points S2, the detection accuracy of the phase error is low.

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. Whether to detect the phase error at both signal points S2 is set based on the required accuracy, the predicted phase error amount, and the like.

Further, the phase error is always detected by each of the full signal point detection unit 21 and the specific range detection unit 23 in parallel, and the full range phase error signal is transmitted from the full signal point detection unit 21 to the carrier reproduction control switch 20. Is constantly supplied and a specific range phase error signal is constantly supplied from the specific range detection unit 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 reproduction control switch 20, and numerically controls the specific range phase error signal after removing the high frequency components. Output to the frequency control terminal of the oscillator 13. Then, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the specific range phase error signal after removing the high frequency component output from the loop filter 12, and outputs the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. .. That is, the carrier regeneration unit 10 performs carrier regeneration processing using the specific range phase error signal supplied from the specific range detection unit 23.

The carrier regeneration control switch 20 is connected to the specific range detection unit 23 to supply a specific range phase error signal to the loop filter 12 (to the numerical control oscillator 13), and the power is reduced. A predetermined time has elapsed since the power recovery notification signal output from the detection unit 2 was input (except when the power recovery notification signal is not input), and the phase slip detection signal 3 outputs the signal. When a predetermined time has elapsed since the phase recovery notification signal was input (except when the phase recovery notification signal is not input), the connection with the all signal point detection unit 21 is performed as normal carrier reproduction. To the loop filter 12 of the carrier regeneration unit 10 (and by extension, to the numerical control oscillator 13), a full-range phase error signal is supplied as a parameter to be supplied to the carrier regeneration unit 10.

When the specific range phase error output from the specific range detection unit 23 becomes less than a predetermined threshold value, the carrier reproduction control switch 20 switches to the connection with the all signal point detection unit 21 to reproduce the carrier. A full-range phase error signal may be supplied to the loop filter 12 of the unit 10 (by extension, to the numerically controlled oscillator 13) as a parameter to be supplied to the carrier reproduction unit 10.

Further, the carrier regeneration control switch 20 is connected to the specific range detection unit 23 to supply a specific range phase error signal to the loop filter 12 (to the numerical control oscillator 13). When the power fluctuation notification signal output from the power drop detection unit 2 is input, or when the slip notification signal output from the phase slip detection unit 3 is input, the connection with the hold output unit 22 is established. After switching, the loop filter 12 of the carrier reproduction unit 10 outputs a reproduction hold signal as a parameter to be supplied to the carrier reproduction unit 10.

Next, the operation and operation of the wireless receiver 1 having such a configuration will be described with reference to FIG.

First, the 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 transferred to the wireless communication device 101 (the wireless communication device 101 on the receiving side in this communication). ) Is receiving. At this time, as usual, the carrier reproduction control switch 20 of the wireless communication device 101 on the receiving side is connected to the all signal point detection unit 21 and is connected to the loop filter 12 of the carrier reproduction unit 10 (by extension, numerical control). A full-range phase error signal (to the oscillator 13) is supplied, and the loop filter 12 removes and outputs a high-frequency component of the full-range phase error signal supplied from the carrier regeneration control switch 20. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a 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 the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. ing. That is, the carrier reproduction unit 10 performs carrier reproduction processing using the full-range phase error signal supplied from the all signal point detection unit 21 (step S0).

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

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

Subsequently, the carrier reproduction control switch 20 to which the power fluctuation notification signal or the slip notification signal is input switches to the connection with the hold output unit 22, and outputs the reproduction hold signal to the loop filter 12 of the carrier reproduction unit 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 determines a predetermined phase error signal while extremely narrowing the loop bandwidth of the PLL. The frequency component is removed (that is, the carrier reproduction loop in the carrier reproduction unit 10 is held; step S5).

Next, when the power reduction detection unit 2 that outputs the power fluctuation notification signal detects that the power fluctuation has subsided and the power has returned to normal for the wireless frame (received signal) output from the phase rotator 11 ( In 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 wireless frame (received signal) output from the phase rotator 11 has returned to normal (step S6b), carrier regeneration control is performed. A phase retrieval 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 retrieval notification signal is input switches to the connection with the specific range detection unit 23, and sends a specific range phase error signal to the loop filter 12 of the carrier reproduction unit 10. Supply (step S8). Then, the loop filter 12 removes the high frequency component of the specific range phase error signal supplied from the carrier regeneration control switch 20 and outputs the signal. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the specific range phase error signal after removing the high frequency component output from the loop filter 12, and outputs the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. And resume carrier regeneration. That is, the carrier regeneration unit 10 restarts the carrier regeneration process by performing phase error compensation using the specific range phase error signal supplied from the specific range detection unit 23 (step S9).

Here, since the all signal point detection unit 21 detects the phase error for all the signal points S2 on the complex plane, the phase error can be detected with high accuracy, but a momentary abnormality of the device such as power fluctuation and phase slip can be detected. If the unstable operation due to the above occurs, the carrier reproduction in the carrier reproduction unit 10 may be out of phase. On the other hand, since the specific range detection unit 23 detects the phase error only at the signal points S2 on the outer side or the inner side far from the origin on the complex plane, the detection accuracy of the phase error is low, but these signal points S2 Since the detectable range of the device is wide, unstable operation is unlikely to occur even if a momentary abnormality occurs in the device, and it is possible to prevent / suppress a situation in which the carrier reproduction unit 10 is out of sync with the carrier reproduction. Therefore, when the carrier regeneration process in the carrier reproduction unit 10 is restarted, the carrier is used as the phase error detection range (detectable range) at the beginning of the restart, which is wider than the normal phase error detection range (detectable range). At the beginning of resumption, when the reproduction process tends to be unstable, the carrier reproduction process (in other words, the carrier reproduction synchronization process) can be smoothly performed.

Subsequently, the carrier regeneration control switch 20 is connected to the specific range detection unit 23 to supply the specific range phase error signal to the loop filter 12 (to the numerical control oscillator 13). , A predetermined time has elapsed since the power recovery notification signal output from the power reduction detection unit 2 was input (except when the power recovery notification signal is not input), and the phase slip detection unit 3 After a predetermined time has passed since the output phase recovery notification signal was input (except when the phase recovery notification signal is not input), the all signal point detection unit 21 and the carrier reproduction in the normal state are performed. The full range phase error signal is supplied to the loop filter 12 of the carrier reproduction unit 10 (and to the numerical control oscillator 13). Then, the loop filter 12 removes the high frequency component of the full-range phase error signal supplied from the carrier regeneration control switch 20 and outputs the signal. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a 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 the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. .. That is, the carrier reproduction unit 10 performs carrier reproduction processing using the full range phase error signal supplied from the all signal point detection unit 21 (step S10).

According to the wireless receiver 1 according to this embodiment, when a fluctuation in the power of the wireless frame or a phase slip is detected, the parameter supplied to the carrier reproduction unit 10 is switched, so that it is caused by an instantaneous abnormality of the device. It is possible to prevent malfunction of carrier reproduction (specifically, out of synchronization), and to stably operate the carrier reproduction unit 10 to realize good demodulation performance (in other words, bit error rate). Become.

According to the wireless receiver 1 according to this embodiment, a phase error having a predetermined characteristic can be set as a parameter by further adjusting the phase error detection range on the complex plane, and the phase error can be set as a parameter. By controlling the carrier regeneration process, it is possible to accurately prevent the carrier regeneration malfunction (specifically, out of synchronization) due to an instantaneous abnormality of the device.

(Embodiment 2)
FIG. 10 is a functional block diagram showing a schematic configuration of the wireless receiver 1 according to the second embodiment of the present invention. Note that FIG. 10 is based on the configuration (see FIG. 1) like the wireless communication device 101 in the wireless communication system 100 described above, 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 specifically receives a characteristic configuration applied to a configuration corresponding to a 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 receiver 1 as a mechanism associated with.

The wireless receiving device 1 according to this embodiment includes a power drop detection unit 2 that monitors the power of the received wireless frame to determine the presence or absence of power fluctuation, and a phase state of the wireless frame that monitors the presence or absence of phase slip. It has a phase slip detection unit 3 for determining the above, and outputs a phase error signal to the numerical control oscillator 13 and the numerical control oscillator 13 which output the phase rotation control signal to the phase rotor 11 which rotates the phase of the wireless frame. The carrier regeneration unit 10 including the loop filter 12 and the carrier regeneration control switch 30 capable of switching the parameters supplied to the carrier regeneration unit 10 are provided, and the power reduction detection unit 2 detects fluctuations in the power of the wireless frame. When the phase slip detection unit 3 detects the phase slip of the wireless frame, the carrier regeneration control switch 30 switches the parameter supplied to the carrier regeneration unit 10.

The radio receiver 1 according to this embodiment further sets the parameter to be a loop filter coefficient indicating the loop bandwidth of the PLL supplied to the loop filter 12.

The wireless receiver 1 according to this embodiment is a circuit that performs carrier wave regeneration processing in digital wireless transmission, and mainly includes a power drop detection unit 2, a phase slip detection unit 3, and a phase error detection unit 7. The carrier regeneration unit 10 and the carrier regeneration control switch 30 are included in the mechanism.

The carrier regeneration unit 10 includes a phase rotator 11, a loop filter 12, and a numerically controlled oscillator 13. In the radio receiver 1, the phase rotating unit 11, the symbol determination unit 4, the error calculation unit 5, the loop filter 12, and the numerically controlled oscillator 13 form a carrier regeneration loop which is a PLL (abbreviation of Phase Locked Loop).

The phase rotator 11 has a function of rotating the phase of the analog-to-digital converted wireless frame (received signal) output from the receiving unit 150. Specifically, the phase rotator 11 performs phase rotation on the wireless frame (received signal) based on a sine wave or a cosine wave as a phase rotation control signal output from the numerical control oscillator 13. Phase error compensation is performed, and a signal with phase error compensation 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 unit 7 according to a predetermined loop bandwidth. Specifically, the loop filter 12 receives the input of the phase error signal and the input of the loop filter coefficient output from the carrier reproduction control switch 30, and removes unnecessary high frequency components from the phase error signal. , The phase error signal after removing the high frequency component is output to the frequency control terminal of the numerical control oscillator 13.

The numerically controlled oscillator 13 (also called "NCO (abbreviation of Numerical Controlled Oscillator)") is a phase for performing phase error compensation by phase rotation based on the phase error signal after removing the high frequency component output from the loop filter 12. It has a function to generate a rotation control signal. Specifically, the numerical control oscillator 13 generates an antiphase sine wave signal or a chord wave signal based on the phase error signal after removing the high frequency component output from the loop filter 12, and uses the generated phase rotation control signal as the generated phase rotation control signal. The sine wave signal and the cosine wave signal of the above are output to the phase rotator 11. The phase rotation by the phase rotor 11 is controlled by the phase rotation control signal output from the numerically controlled oscillator 13.

The power reduction detection unit 2 monitors the power (in other words, signal strength) of the wireless frame (received signal) output from the phase rotator 11 of the carrier reproduction unit 10, and has a power sufficient to cause a malfunction of the device. Judge whether or not there is a change in.

The presence or absence of power fluctuation is determined, 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). It is conceivable that this is done based on the degree of contraction of the constellation with respect to the corresponding multi-level QAM rectangular frame when 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 and corresponds to the in-phase component (Ich) after the orthogonal detection process, and the vertical axis is the Q-axis of the complex plane and is orthogonal. Corresponds to the orthogonal component (Qch) after the detection process.

The presence or absence of fluctuations in electric power may be determined based on the average value of electric power over a predetermined time length, or the number of consecutive symbols in which electric power is less than a predetermined value (specifically, For example, it may be performed based on (about 2 to 10 times).

When the power reduction detection unit 2 detects a power fluctuation that may cause a malfunction of the device, the power fluctuation detection unit 2 sends a power fluctuation notification signal to the carrier regeneration control switch 30 to notify that the power fluctuation has occurred. Output. When the power reduction detection unit 2 detects that the power fluctuation has subsided and the power has returned to normal after detecting the power fluctuation, the power recovery for notifying that the power has returned to normal A notification signal is output to the carrier reproduction control switch 30.

The phase slip detection unit 3 monitors the phase state of the radio frame (received signal) output from the phase rotator 11 of the carrier reproduction unit 10 and determines the presence or absence of the phase slip. The presence or absence of phase slip is determined by using a known pattern signal inserted into the 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 rotated to change the phase. It is conceivable to determine the presence or absence of phase slip based on the proportion of signal points protruding outside the rectangular frame of the multi-level QAM in the normal state (see FIGS. 3 and 5). The ratio of the signal points for determining whether or not the phase slip is not limited to a specific value, and is an appropriate value after considering, for example, the characteristics of the communication device and the modulation method. Is set as appropriate.

In the case of phase slip, the phase state is not determined, and the distribution of signal points fluctuates with respect to the rectangular frame of the multi-level QAM when the phase is normal, and the above-mentioned Signal points extend beyond any area around the rectangular frame of the multi-level QAM (see FIG. 5). On the other hand, when the phase slip has subsided and the phase is stable, the distribution of the signal points protruding outside the rectangular frame of the multi-level QAM when the phase is normal is the distribution of the multi-level QAM. It is constant whether it lags or advances with respect to the rectangular frame, and is biased to a specific area outside the rectangular frame of the multi-value QAM (see FIG. 6; in FIG. 6, the area 1 is phased. Is the area where the signal point protrudes when rotating in the forward direction, and area 2 is the area where the signal point protrudes when the phase is rotating in the lagging direction). Therefore, it is conceivable to determine the presence or absence of phase slip in consideration of the distribution of signal points protruding outside the rectangular frame of the multi-level QAM.

When the phase slip detection unit 3 detects the phase slip, the phase slip detection unit 3 outputs a slip notification signal for notifying that the phase slip has occurred to the carrier regeneration control switch 30. When the phase slip detection unit 3 detects that the phase slip has subsided and the phase state has returned to normal after detecting the phase slip, the phase retrieval unit 3 is for notifying that the phase state has returned to normal. A notification signal is output to the carrier reproduction control switch 30.

The symbol determination unit 4 performs symbol determination on a signal output from the phase rotator 11 of the carrier reproduction unit 10 whose phase is rotated by the phase rotator 11 and whose phase error is compensated.

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 unit 5 is composed of a subtractor.

The decoding unit 6 receives the input of the signal output from the symbol determination unit 4, performs an error correction decoding process on the signal, and outputs the transmission data generated by the decoding process to the interface unit 110.

The phase error detection unit 7 detects the phase error component in cooperation with the error calculation unit 5, and represents the phase error signal (specifically, the phase error as a voltage value) corresponding to the detected phase error component. The 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 unit 31, the narrow band coefficient output unit 32, and the wideband coefficient output unit 33 and supplying them to the loop filter 12. To be equipped. The carrier regeneration control switch 30 is connected to any one of the normal coefficient output unit 31, the narrow band coefficient output unit 32, and the wideband coefficient output unit 33 according to the signals output from the power reduction detection unit 2 and the phase slip detection unit 3. To switch.

In the normal state, the carrier regeneration control switch 30 is connected to the normal coefficient output unit 31 in which the loop filter coefficient in the normal state is stored in advance, and the loop filter 12 of the carrier reproduction unit 10 is connected to the carrier reproduction unit 10. As a parameter to be supplied, a loop filter coefficient (referred to as “normal time coefficient”) indicating a normal loop bandwidth is supplied.

In this case, the loop filter 12 uses the normal time coefficient supplied from the normal coefficient output unit 31 via the carrier regeneration control switch 30, and uses an unnecessary high frequency of the phase error signal output from the phase error detection unit 7. The component is removed, and 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 numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the phase error signal after removing the high frequency component output from the loop filter 12, outputs the signal as a phase rotation control signal, and performs phase rotation. The device 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. That is, the carrier regeneration unit 10 performs carrier regeneration processing using the normal time constant supplied from the normal coefficient output unit 31.

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

The carrier regeneration control switch 30 is connected to the narrow band coefficient output unit 32 to supply the narrow band coefficient to the loop filter 12, and then the power fluctuation notification signal output from the power reduction detection unit 2 is further input. Or, when the slip notification signal output from the phase slip detection unit 3 is further input, the carrier is connected to the loop filter 12 of the carrier reproduction unit 10 while being connected to the narrow band coefficient output unit 32. A narrow band coefficient is supplied as a parameter to be supplied to the reproduction unit 10.

The narrow band coefficient is a signal whose content is such that the loop bandwidth used in the removal process of the high frequency component by the loop filter 12 is set extremely narrow.

When the narrow band coefficient output from the narrow band coefficient output unit 32 is supplied via the carrier reproduction control switch 30, the loop filter 12 uses the narrow band coefficient to extremely narrow the loop bandwidth of the PLL. However, a process of removing a predetermined frequency component from the phase error signal output from the phase error detection unit 7 is performed.

As the narrow bandwidth coefficient, a value with a loop bandwidth narrower than the normal time coefficient is set. The loop bandwidth as the narrow bandwidth coefficient is not limited to a specific value, but the loop bandwidth used in the removal processing of the high frequency component by the loop filter 12 is extremely narrowed, and the lock time of the PLL (that is, synchronization) is made. The carrier regeneration loop in the carrier regeneration unit 10 is set to a value that can be held in a pseudo manner by lengthening the time until the carrier regeneration unit 10 is taken.

The carrier regeneration control switch 30 is further connected to the narrow band coefficient output unit 32 to output the narrow band coefficient to the loop filter 12, and then the power recovery notification signal output from the power reduction detection unit 2 is input. 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 coefficient is stored in advance, and carrier reproduction is performed. A loop filter coefficient (referred to as “broadband coefficient”) indicating a wideband loop bandwidth is supplied to the loop filter 12 of the unit 10 as a parameter to be supplied to the carrier reproduction unit 10.

As the wideband coefficient, a value with a loop bandwidth wider than the normal time coefficient is set. The loop bandwidth as a broadband coefficient is not limited to a specific value, but increases due to fluctuations in the power of the radio frame (received signal) and detection errors that occur in normal times before phase slip is detected. It is appropriately set to an appropriate value after considering the appropriate removal of the phase error and the shortening of the PLL lock time (that is, the time until synchronization). When the power recovery notification signal is output to the carrier regeneration control switch 30 after the power fluctuation detection signal is output from the power reduction detection unit 2 (that is, when the power fluctuation occurs and the power is recovered). , The broadband coefficient may be different depending on whether the phase recovery notification signal is output after the slip notification signal is output from the phase slip detection unit 3 (that is, when the phase slip occurs and recovers). Further, the broadband coefficient may be appropriately set by the user.

The loop filter 12 removes a predetermined frequency component of the phase error signal output from the phase error detection unit 7 by using the wideband coefficient supplied from the wideband coefficient output unit 33 via the carrier reproduction control switch 30. The phase error signal after removing the predetermined frequency component is output to the frequency control terminal of the numerically controlled oscillator 13. Then, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the phase error signal after removing the predetermined frequency component output from the loop filter 12, and outputs the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. .. That is, the carrier regeneration unit 10 performs carrier regeneration processing using the broadband coefficient supplied from the broadband coefficient output unit 33.

The carrier regeneration control switch 30 is connected to the wideband coefficient output unit 33 to supply the wideband coefficient to the loop filter 12, and after the power recovery notification signal output from the power reduction detection unit 2 is input. A predetermined time has elapsed (except when the power recovery notification signal has not 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, a predetermined time has elapsed (except when the power recovery notification signal has not been input). However, when the phase retrieval notification signal is not input), the connection with the normal coefficient output unit 31 is switched to the normal coefficient output unit 31 as the carrier reproduction in the normal time, and the loop filter 12 of the carrier reproduction unit 10 is used. , The normal time coefficient is supplied as a parameter to be supplied to the carrier regeneration unit 10.

The wideband coefficient output unit 33 sets a loop filter coefficient, which indicates a wideband loop bandwidth as a wideband coefficient to be output / supplied to the carrier reproduction control switch 30 and thus to the loop filter 12, at a predetermined time. Over time, the output / supply may be gradually reduced from the wideband coefficient 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 unit 33 to supply the wideband coefficient to the loop filter 12, and the power fluctuation notification signal output from the power reduction detection unit 2 is input. Or, when a slip notification signal output from the phase slip detection unit 3 is input, the connection with the narrow band coefficient output unit 32 is switched to the loop filter 12 of the carrier reproduction unit 10. Then, the narrow band coefficient is output as a parameter to be supplied to the carrier reproduction unit 10.

Next, the operation and operation of the wireless receiver 1 having such a configuration will be described with reference to FIG.

First, the 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 transferred to the wireless communication device 101 (the wireless communication device 101 on the receiving side in this communication). ) Is receiving. At this time, as a normal time, the carrier reproduction control switch 30 of the wireless communication device 101 on the receiving side connects with the normal coefficient output unit 31 to supply the normal time coefficient to the loop filter 12 of the carrier reproduction unit 10, and then , The loop filter 12 removes the high frequency component of the phase error signal output from the phase error detection unit 7 and outputs it by using the normal time coefficient supplied from the carrier reproduction control switch 30. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the phase error signal after removing the high frequency component output from the loop filter 12, outputs the signal as a phase rotation control signal, and performs phase rotation. The device 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. .. That is, the carrier regeneration unit 10 performs carrier regeneration processing using the normal time constant supplied from the normal coefficient output unit 31 (step S0).

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

Then, when the power reduction detection unit 2 detects a power fluctuation of the wireless frame (received signal) output from the phase rotator 11 to the extent that it may cause a malfunction of the device (step S2a), the carrier regeneration control switch 30 A power fluctuation notification signal is output to the above (step S3a). Alternatively, when the phase slip detection unit 3 detects the phase slip of the wireless frame (received signal) output from the phase rotator 11 (step S2b), the phase slip detection unit 3 outputs a slip notification signal to the carrier reproduction control switch 30 (step S2b). 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 narrow band coefficient output unit 32, and the narrow band coefficient is set with respect to the loop filter 12 of the carrier reproduction unit 10. (Step S4). Then, the loop filter 12 to which the narrow band coefficient is supplied uses the narrow band coefficient to extremely narrow the loop bandwidth of the PLL, and determines the predetermined phase error signal output from the phase error detection unit 7. Performs a process to remove the frequency component of. In this case, since the loop bandwidth used in the processing for removing the high frequency component by the loop filter 12 is extremely narrow, the lock time of the PLL (that is, the time until synchronization is achieved) becomes long, and the carrier regeneration loop in the carrier regeneration unit 10 becomes long. It is held in a pseudo manner (step S5).

Next, when the power reduction detection unit 2 that outputs the power fluctuation notification signal detects that the power fluctuation has subsided and the power has returned to normal for the wireless frame (received signal) output from the phase rotator 11 ( Step S6a), the 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 wireless frame (received signal) output from the phase rotator 11 has returned to normal (step S6b), carrier regeneration control is performed. A phase retrieval 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 retrieval notification signal is input switches to the connection with the wideband coefficient output unit 33, and supplies the wideband coefficient to the loop filter 12 of the carrier reproduction unit 10 ( Step S8). Then, the loop filter 12 removes a predetermined frequency component from the phase error signal output from the phase error detection unit 7 and outputs the band using the wideband coefficient supplied from the carrier reproduction control switch 30. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the phase error signal after removing the predetermined frequency component output from the loop filter 12, and outputs the signal as a phase rotation control signal. The phase rotator 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 with respect to the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. And resume carrier regeneration. That is, the carrier regeneration unit 10 restarts the carrier regeneration process by performing phase error compensation using the broadband coefficient supplied from the broadband coefficient output unit 33 (step S9).

Here, the normal time coefficient output from the normal coefficient output unit 31 is the lock time of the PLL (in other words, the followability of the carrier reproduction loop to the phase change) and the phase noise value (also referred to as “C / N value”). 7 between and is set to be appropriate, and although a good phase noise value can be secured in normal times, unstable operation due to momentary abnormalities of the equipment such as power fluctuation and phase slip may occur. If this occurs, the locking time of the PLL becomes long, the carrier reproduction loop cannot sufficiently follow the phase change, and the phase noise value may drop significantly. On the other hand, in the wideband coefficient output from the wideband coefficient output unit 33, a loop bandwidth value wider than the normal time coefficient is set, so that the high frequency component of the phase error signal output from the phase error detection unit 7 is set. Although the phase noise value is slightly reduced because the , The lock time of the PLL is shortened, and the carrier reproduction loop can sufficiently follow the phase change. Therefore, when resuming the carrier regenerating process in the carrier regenerating unit 10, by using a loop bandwidth wider than the normal time as the loop bandwidth at the beginning of resuming, the regenerating process of the carrier tends to be unstable. Initially, carrier regeneration processing (in other words, carrier regeneration synchronization processing) can be smoothly performed.

Subsequently, the power recovery notification signal output from the power reduction detection unit 2 is input while the carrier regeneration control switch 30 is connected to the broadband coefficient output unit 33 to supply the broadband coefficient to the loop filter 12. A predetermined time has elapsed since the 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 unit 3 was input. After the lapse of time (except when the phase retrieval notification signal is not input), the connection with the normal coefficient output unit 31 is switched to the loop filter 12 of the carrier reproduction unit 10 as the carrier reproduction in the normal time. And supplies the normal time coefficient. Then, the loop filter 12 removes the high frequency component of the phase error signal output from the phase error detection unit 7 and outputs it by using the normal time coefficient supplied from the carrier reproduction control switch 30. Further, the numerical control oscillator 13 generates an antiphase sine wave signal or a cosine wave signal based on the phase error signal after removing the high frequency component output from the loop filter 12, outputs the signal as a phase rotation control signal, and performs phase rotation. The device 11 performs phase rotation controlled by the phase rotation control signal output from the numerical control oscillator 13 on the analog-digitally converted wireless frame (received signal) output from the receiving unit 150. That is, the carrier regeneration unit 10 performs carrier regeneration processing using the normal time constant supplied from the normal coefficient output unit 31 (step S10).

According to the wireless receiver 1 according to this embodiment, when a fluctuation in the power of the wireless frame or a phase slip is detected, the parameter supplied to the carrier reproduction unit 10 is switched, so that it is caused by an instantaneous abnormality of the device. It is possible to prevent malfunction of carrier reproduction (specifically, out of synchronization), and to stably operate the carrier reproduction unit 10 to realize good demodulation performance (in other words, bit error rate). Become.

According to the wireless receiver 1 according to this embodiment, a loop filter coefficient having a predetermined characteristic can be set as a parameter by further 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 device, it is possible to accurately prevent the carrier regeneration malfunction (specifically, out of synchronization) due to an instantaneous abnormality of the device.

Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like within a range that does not deviate from the gist of the present invention, this embodiment is described. Included in the invention. Specifically, in the above-described embodiment, the wireless communication device 101 shown in FIG. 1 is mentioned as a base configuration to which the wireless reception device 1 according to the present invention is applied. 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 associated with reception (in other words, related to reception). Any configuration may be used as long as it is a wireless communication device (which can be incorporated into the mechanism). Specifically, for example, any configuration may be used as long as it is a wireless communication device including a configuration corresponding to the carrier reproduction unit 10 in the above embodiment.

Further, in the above embodiment, both the power reduction detection unit 2 and the phase slip detection unit 3 are provided, but the provision of these two is not an essential configuration in the present invention, and the power reduction detection unit is not essential. At least one of 2 and the phase slip detection unit 3 may be provided.

1 Wireless receiver 2 Power drop detection unit 3 Phase slip detection unit 4 Symbol judgment unit 5 Error calculation unit 6 Decoding unit 7 Phase error detection unit 10 Carrier regeneration unit 11 Phase rotor 12 Loop filter 13 Numerically controlled oscillator 20 Carrier regeneration control switch (Embodiment 1)
21 All signal point detection unit 22 Hold output unit 23 Specific range detection unit 30 Carrier regeneration control switch (Embodiment 2)
31 Normal coefficient output unit 32 Narrowband coefficient output unit 33 Broadband coefficient output unit 100 Wireless communication system 101 Wireless communication device 102 Antenna 103 Wireless line 110 Interface unit 111 Data line termination device 120 Modulation unit 130 Transmitter unit 140 Demultiplexer 150 Receiver unit 160 Demoder

Claims (4)

A power reduction detection unit that monitors the power of the received wireless frame and determines whether or not the power fluctuates.
It has at least one of a phase slip detection unit that monitors the phase state of the radio frame and determines the presence or absence of phase slip, and also has
A carrier reproduction unit including a numerical control oscillator that outputs a phase rotation control signal to a phase rotator that rotates the phase of the wireless frame and a loop filter that outputs a phase error signal to the numerical control oscillator.
It has a switch capable of switching parameters supplied to the carrier reproduction unit, and has.
When the power reduction detection unit detects the fluctuation of the power of the radio frame, or when the phase slip detection unit detects the phase slip of the radio frame,
The switch switches the parameter supplied to the carrier reproduction unit.
A wireless receiver characterized by that. The parameter is the phase error detected by setting the phase error detection range on the complex plane to a predetermined range, which is supplied to the loop filter.
The wireless receiving device according to claim 1. The parameter is a loop filter coefficient indicating the loop bandwidth of the PLL supplied to the loop filter.
The wireless receiving device according to claim 1. 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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