JP5735863B2 - Wireless communication apparatus, transmission method, and program - Google Patents

Description

  The present invention relates to a wireless communication apparatus that transmits a signal by switching between a wide directional antenna and a narrow directional antenna, a transmission method of the wireless communication apparatus, and a program.

  In a communication system, an omnidirectional antenna or a wide directional antenna having a wide beam width can generally communicate with a wireless communication apparatus existing in a wide angle range, but the antenna gain is not large, so the communicable distance is short. . For this reason, it is necessary to increase transmission power in order to communicate with a wireless communication device that exists far away. On the other hand, a narrow directional antenna with a narrow beam width has advantages such as a large antenna gain, a long communication distance, and communication with a distant wireless communication apparatus with the same power as a wide directional antenna. However, the narrow directional antenna has a problem that it can communicate only with a wireless communication device existing in a narrow angle range.

  As a narrow directional antenna, a phased array antenna having a high antenna gain in a direction in which a plurality of antenna elements are arranged and the phase of a signal input to each antenna element is matched has been known. The phased array antenna is characterized in that the directivity direction and beam width can be changed by changing the phase of a signal input to each antenna element. Patent Document 1 and Patent Document 2 describe that an antenna pattern having a wide directivity can be obtained by using only a part of the phased array antenna. In addition, by switching to a wide directional antenna different from the phased array antenna, communication utilizing both narrow directivity and wide directivity characteristics is possible.

JP-A-6-164233 JP 2003-229713 A

  In a phased array antenna having a general configuration, an individual amplifier is connected to each antenna element. FIG. 7 shows an example of an RF circuit configuration using a general phased array antenna. In the phased array antenna, the reception power at an ideal reception point is the square of the number of amplifiers if the individual amplifier outputs are ideally combined. This is because, for example, at the point where the phases of sine waves output from a plurality of antenna elements match, the waves are strengthened and radio waves having a current whose amplitude is several times that of the antenna elements are received. For example, in FIG. 7, when radio waves radiated from the four antenna elements 7051 to 7054 of the phased array antenna 705 are received with ideally the same phase, the power is about 16 times that when only one antenna element is used. Will receive radio waves. Therefore, the amplification capability of each amplifier may be small.

  On the other hand, in FIG. 7, there is an RF switch 704 for turning on / off the RF signal between each antenna element and the amplifier as in Patent Document 1 and Patent Document 2, and a part of this RF switch 704 is turned off. Thus, the antenna can have a wide directivity. However, as is clear from the above description, when the RF switches 704b to 704d are turned off and only the antenna element 7051 is fed, the reception power at the ideal reception point when using the phased array antenna is 1/16. Become. For this reason, there existed a subject that communication distance will become very short.

  On the other hand, as shown in FIG. 8, a separate circuit may be configured for the wide directional antenna 804, and an amplifier 802 having a large output power may be used. However, there is a problem that an extremely high performance amplifier must be used in order to amplify linearly without distortion for a signal having a large peak power to average power ratio such as OFDM.

  For a signal having a large peak power to average power ratio, it is conceivable that the combiner 904 combines the output of the amplifier 903 having a relatively small output power as shown in FIG. However, in this case, the signal distributed from the distributor 901 has a phase difference due to the difference in the length of each transmission line and the matching of ICs such as amplifiers and RF switches while reaching the input terminal of the combiner 904. Deviation occurs. For this reason, in the synthesizer 904, the phase shifter 902 needs to be inserted in order to match the phases of these distributed signals, and there is a problem that the circuit scale increases.

  The present invention has been made in view of the above problems, and relates to a wireless communication apparatus that switches between a wide directional antenna and a narrow directional antenna, and a technique for transmitting a signal with sufficient power while suppressing a circuit scale. The purpose is to provide.

In order to achieve the above object, a wireless communication apparatus according to the present invention includes a distribution unit that distributes an input signal to a plurality of signals, and at least changes a phase of at least one of the plurality of signals. and one phase shifting means, a plurality of amplifying means for amplifying the power of the plurality of signals, for each of a plurality of signal power is amplified by the amplifying means, the plurality of antennas corresponding to each of said amplifying means A plurality of switching means for switching whether to output to a combiner that combines the plurality of signals and outputs to at least one antenna, and the plurality of switching means select the output destination of the plurality of signals And control means for controlling the amount of the phase to be changed by the at least one phase shifting means based on how it is switched.

In order to achieve the above object, a wireless communication apparatus according to the present invention includes a distribution unit that distributes an input signal belonging to a baseband or an intermediate frequency band to a plurality of signals, and a center frequency of the plurality of signals. A plurality of conversion means for converting using any one of a plurality of reference signals obtained by distributing from one reference signal, and a phase of at least one of the plurality of reference signals At least one phase shifting means for changing, a plurality of amplifying means for amplifying the power of the plurality of signals, and a plurality of signals corresponding to each of the amplifying means for each of the plurality of signals whose power is amplified by the amplifying means. whether to output to the antenna, or switches whether to output to the synthesizer output to at least one antenna by combining the plurality of signals, and a plurality of switching means, said plurality Switching means, based on how switches the output destination of the plurality of signals, said characterized in that it comprises a control means for controlling the amount of the phase of at least one phase shifting means is varied, the.

  According to the present invention, in a wireless communication apparatus that switches between a wide directional antenna and a narrow directional antenna, a signal can be transmitted with sufficient power while suppressing a circuit scale.

1 is a block diagram illustrating a configuration example of a wireless communication device. The block diagram which shows the structural example of a phase control part. The block diagram which shows the structural example of the radio | wireless communication apparatus in case one of the antenna elements of an array antenna is used as a wide directivity antenna. The block diagram which shows the structural example of a radio | wireless communication apparatus provided with a frequency conversion part. The block diagram which shows the structural example of the radio | wireless communication apparatus provided with a frequency conversion part and changing the phase of a reference signal. The block diagram which shows the structural example of the radio | wireless communication apparatus in the case of making the output of an amplifier variable. The block diagram which shows the structural example of the radio | wireless communication apparatus based on a prior art in case one of the antenna elements of an array antenna is used as a wide directivity antenna. The block diagram which shows the structural example of the radio | wireless communication apparatus which concerns on the prior art provided with the circuit for wide directivity antennas separately from an array antenna. The block diagram which shows the structural example of the radio | wireless communication apparatus which concerns on the prior art in the case of providing the circuit for wide directivity antennas separately from an array antenna, and synthesize | combining the output of an amplifier. The block diagram which shows the structural example of the radio | wireless communication apparatus at the time of using an amplifier separately also as a phase shifter.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<< Embodiment 1 >>
(Configuration of wireless communication device)
A configuration example of the wireless communication apparatus according to the first embodiment is shown in FIG. The wireless communication apparatus inputs a signal from a radio frequency (RF) signal input terminal 100 and radiates a radio wave from the phased array antenna 105 or the wide directional antenna 107. The input RF signal is distributed into a plurality by the distributor 101. The signal distributed by the distributor 101 is input to the phase shifter 102. The phase shifter 102 changes the phase of the plurality of distributed RF signals and inputs it to the amplifier (PA) 103. Note that the phase shifter 102 does not need to change the phase with respect to all of the plurality of distributed RF signals. For example, the phase may be fixed for a part of the RF signals, and the phase of the components other than the part of the RF signals may be changed using the fixed RF signal as a reference. The example of FIG. 1 is an example of a configuration in which the phase of one RF signal is not changed. When the phase is not changed, the phase shifter 102 can be omitted.

  The amplifier 103 inputs the amplified RF signal to the RF switch 104. In addition, although the amplifier 103 is inserted in the subsequent stage of the phase shifter 102 in the example of a figure, it is not restricted to this. For example, the amplifier 103 may be inserted before the phase shifter 102 or may be inserted both before and after. The RF switch 104 is a switching device that switches output destinations of the amplified RF signals from the antenna elements 1051 to 1054 corresponding to the amplifiers 103 and the combiner 106 that combines the RF signals. In other words, the RF switch 104 switches whether the wireless communication apparatus transmits a signal using the phased array antenna 105 or transmits a signal using the single wide directional antenna 107. Note that the output destination of the signal input to the RF switch 104 is controlled by the switch control unit 109.

  The signal synthesized by the synthesizer 106 is radiated from a single wide directional antenna 107. Note that signal synthesis is performed, for example, by adding input signals.

  Each antenna element 1051 to 1054 of the phased array antenna 105 radiates a signal input from the corresponding amplifier 103. Here, the phased array antenna is formed by arranging a plurality of antenna elements, and a beam having a specific shape is formed according to the phase of the signal input from each of the antenna elements 1051 to 1054. That is, by controlling the phase of the signal input to the antenna elements 1051 to 1054, the shape of the formed beam can be controlled. In the present embodiment, the pointing direction and the beam width are controlled by changing the phase of the signal in the phase shifter 102 corresponding to the antenna elements 1052 to 1054. The directivity direction is, for example, the principal axis direction of the emitted beam. In this embodiment, the phased array antenna 105 operates as a narrow directional antenna, and the phase shifter 102 corresponding to the antenna elements 1052 to 1054 is used for controlling the directivity.

  The phase control unit 108 controls the phase shifter 102 and adjusts the phase of signals input to the phased array antenna 105 and the combiner 106. Specifically, for the signal input to the phased array antenna 105, initial phase correction of each of the antenna elements 1051 to 1054 and phase adjustment for controlling the directivity direction are performed. In addition, the signal input to the combiner 106 is subjected to phase correction to make the signal phase substantially in phase in order to increase the output from the wide directional antenna 107. Note that the phase of the signal input to the combiner 106 does not have to be completely in phase, and may be in phase. That is, it suffices if a plurality of input signal components are added in substantially the same phase and can be mutually strengthened.

  The wireless communication apparatus according to the present embodiment controls the phase shifter 102 so that the phase control unit 108 causes a different amount of phase fluctuation depending on whether the phased array antenna 105 or the wide directional antenna 107 is used. To do. That is, the phase control unit 108 changes the phase amount of the signal to be shifted in accordance with the signal output destination in the RF switch 104. As a result, when switching between the phased array antenna 105 and the wide directional antenna 107, a phase shifter and an amplifier can be shared between the antennas, and radio waves can be radiated with sufficient power while suppressing the circuit scale. It becomes.

(Configuration of phase control unit)
FIG. 2 shows an example of the internal configuration of the phase control unit 108. In the figure, a processing unit 1081 controls the phase of each of a plurality of phase shifters 102. The first memory 1082 stores a value for correcting the initial phase of the antenna elements 1051 to 1054 of the phased array antenna 105, and the second memory 1083 stores a phase correction value for adjusting the input phase of the combiner 106. The initial phase correction value when signals are input to the phased array antenna 105 and the combiner 106 is determined in advance and stored in the first memory 1082 and the second memory 1083. These initial values may be stored individually before shipping the product, for example, and before use, the initial phase is determined by exchanging test signals with a receiver (not shown), and the result is obtained. It may be memorized.

  An example of a method for determining the initial phase in each of the antenna elements 1051 to 1054 of the phased array antenna 105 is shown below. First, the antenna element 1051 and one of the other antenna elements, for example, the antenna element 1052 are selected and a signal is output. Specifically, the RF switches 104 a and 104 b are connected to the antenna elements 1051 and 1052 of the phased array antenna 105. Then, signals are not input to other antenna elements by a signal breaker (not shown), for example, an output enabler of the amplifier 103. Then, a specific signal is transmitted while changing the phase of the input signal to the antenna element 1052 by the phase shifter 102a. The transmitted signal is received by a receiver (not shown), a power meter, or the like at a reception point having a predetermined positional relationship with the phased array antenna 105. For example, when the processing unit 1081 receives an information signal related to received power from a not-shown receiver or the like, the processing unit 1081 temporarily stores the relationship between the phase change amount and the received power. Then, the processing unit 1081 searches for the phase of the antenna element 1052 having the maximum combined power received at the reception point, and stores the phase in the first memory 1082 as an initial phase correction value.

  The processing unit 1081 searches for the correction value of the initial phase for the other antenna elements 1053 and 1054 in the same procedure, and stores it in the first memory 1082. Note that, for example, when the antenna elements are arranged in a straight line, the predetermined positional relationship described above is preferably a position sufficiently separated from the central portion of the antenna array in the vertical direction of the array direction. In addition, even if this position is other than this, as long as the relative positional relationship with an antenna can be understood, it may be anywhere.

  Next, an example of a method for determining the initial phase of the input signal of the combiner 106 in the wide directivity antenna 107 will be described below. First, the RF switch 104 a and one of the other RF switches, for example, the RF switch 104 b are connected to the combiner 106. And the signal input into other RF switch 104c, 104d is interrupted | blocked with a signal breaker not shown. Then, a specific signal is transmitted while the phase of the input signal to the RF switch 104b is changed by the phase shifter 102a. This transmitted signal is received at a predetermined reception point by a receiver (not shown), a power meter or the like. The predetermined reception point here may be at an arbitrary position. For example, when the processing unit 1081 receives an information signal related to received power from a not-shown receiver or the like, the processing unit 1081 temporarily stores the relationship between the phase change amount and the received power. Then, the processing unit 1081 searches for the phase of the antenna element 1052 that maximizes the power of the signal received at the reception point, and stores the phase in the second memory 1083 as an initial phase correction value. For the signals input to the other RF switches 104c and 104d, the initial phase correction value is acquired in the same procedure and stored in the second memory 1083.

  The processing unit 1081 receives from the switch control unit 109 a signal indicating which of the phased array antenna 105 or the wide directional antenna 107 has been selected. If the phased array antenna 105 is selected according to the value, the initial phase correction value is read from the first memory 1082, and if the wide directivity antenna 107 is selected, the initial phase correction value is read from the second memory 1083. Further, when the phased array antenna 105 is selected, the processing unit 1081 causes the phase to be taken by the plurality of signals input to the antenna elements 1051 to 1054 so that the main axis direction of the beam is the pointing direction input from the outside. Calculate the value of. Then, based on the calculated phase value and the initial phase correction value called from the first memory 1082, the amount of phase to be changed in each of the plurality of phase shifters 102 is determined. Here, the amount of phase to be changed is, for example, the sum of the calculated phase value and the initial phase correction value. The processing unit 1081 controls the phase shifter 102 in accordance with the determined amount of phase to be changed.

  As described above, when the phased array antenna 105 is used, the phase shifter 102 is controlled so that the main axis direction of the beam is directed in a predetermined direction in addition to the correction of the initial phase. When wide directional antenna 107 is used, phase shifter 102 is controlled so that the signal input to combiner 106 has substantially the same phase so that the combined signal has sufficient power. Thereby, when the phased array antenna 105 and the wide directional antenna 107 are switched and used, sufficient transmission signal power can be ensured without increasing the number of phase shifters 102 and amplifiers 103.

<< Embodiment 2 >>
FIG. 3 is a diagram showing a configuration example when one of the antenna elements 1051 of the phased array antenna 105 is used as a wide directional antenna in the wireless communication apparatus of FIG. In FIG. 3, the RF switch 301 outputs the output of the combiner 106 when the wide directional antenna 107 is selected, and the signal output from the RF switch 104a when the phased array antenna 105 is selected. Output.

  If a wide directional antenna is used as another antenna as shown in FIG. 1, there is an effect that the antenna can be customized for wide directivity, and if one of the phased array antennas is used as a wide directional antenna as shown in FIG. This has the effect of reducing the number of antennas. That is, an appropriate form can be adopted depending on the situation from the wireless communication apparatus of FIG. 1 and the wireless communication apparatus of FIG.

  Note that the output of the antenna element 1051 may be less than the other antenna elements 1052 to 1054 due to loss in the RF switch 301. Such loss, gain error of the arrayed circuit, and the like can be adjusted by a gain adjustment circuit (not shown) by measuring the antenna output power for each individual antenna element in advance.

  FIG. 6 shows a configuration example in which the amplifier output is changed when the phased array antenna 105 and the wide directional antenna 107 are switched. In FIG. 6, reference numeral 603 denotes a variable gain amplifier, which is connected to a switch control unit 109 that switches between the phased array antenna 105 and the wide directional antenna 107. With such a configuration, when power is regulated by the antenna output, a signal with sufficient power is transmitted when a wide directional antenna with a low antenna gain is used by increasing the gain of the variable gain amplifier 603. It becomes possible. Furthermore, when the phased array antenna is selected, the signal level input to each antenna can be adjusted by the variable gain amplifier 603, so that it is possible to form a desired directivity pattern such as sidelobe suppression.

<< Embodiment 3 >>
A third embodiment of the present invention is shown in FIG. In the figure, the same numbers as those in FIG. A local signal represented by a sine wave of a reference frequency (local frequency) output from a local oscillator or the like is input to the local signal input terminal 401. The input local signal is distributed by the distributor 402 and input to the mixer 403. The mixer 403 multiplies the local signal by the signal input from the phase shifter 404 and the distributor 101, and converts the center frequency of the signal.

  On the other hand, an intermediate frequency (IF) signal is input from the input terminal 400. The phase shifter 404 is inserted to change the phase in the intermediate frequency band. The input signal may be a baseband signal instead of an intermediate frequency band signal.

  With this configuration, the circuit scale is larger than that of the first embodiment, but the phase of a signal in a frequency band sufficiently lower than that of the RF band can be adjusted, and the phase shifter 404 can be created and adjusted. It becomes easy. In general, since the phase shifter has a larger phase shift range as the frequency is higher, this configuration example is particularly effective in communication with a communication bandwidth that is small (a relative bandwidth is small) with respect to the center frequency.

<< Embodiment 4 >>
A fourth embodiment of the present invention is shown in FIG. In the figure, the same numbers as those in FIGS. 1 and 4 are not described. In this configuration example, the phase of the local signal is changed without changing the phase with respect to the signal in the intermediate frequency band or the baseband. Since the phase shifter 501 is inserted in the local signal output circuit, the circuit scale becomes larger than that of the first embodiment. However, for example, when the mixer 403 converts an IF band signal into an RF band signal, the local signal is a signal having a frequency lower than that of the RF band, and therefore phase adjustment can be performed in the lower frequency band. Note that the phase shifter 501 does not need to be applied to all of the plurality of local signals, as shown in FIG. The mixer multiplies the local signal whose phase has been changed by a plurality of signals in the intermediate frequency band or the baseband, and converts the center frequency.

  In general, the local frequency has a higher frequency than the signals in the intermediate frequency band and baseband, but since it is a single frequency, the phase shifter 501 can be easily created and adjusted. Further, when the phase of the local frequency is changed, the RF signal changes the same amount of phase at all frequencies, and thus the directivity direction of the phased array antenna 105 is not affected. Therefore, it is effective when the communication bandwidth is large with respect to the center frequency or when it is difficult to create and adjust the phase shifter in the RF frequency band.

<< Other Embodiments >>
In the above description, the number of antenna elements of the phased array antenna 105 is four and the number of wide directional antennas 107 is one. However, the number of phased array antennas 105 and wide directional antennas is not limited. However, when implemented in a limited size of the wireless communication device, if there are a large number of wide directional antennas 107, it is conceivable that the pointing accuracy is limited thereby. For this reason, it is preferable that the number of wide directional antennas 107 is smaller than the number of antenna elements of the phased array antenna 105. In the above description, the case where the phased array antenna 105 is used has been described in detail. However, the present invention is not limited to this. For example, even when an array antenna is used as in the above-described example, the phase may be controlled so as to form a null in that direction so as not to radiate radio waves in a predetermined direction.

  In each embodiment, parts not directly related to the present invention are omitted, so that filters, amplifiers, matching devices, attenuators, etc. may be inserted as necessary, but these functions are added. However, the present invention is not restricted.

  Further, in order to reduce the loss from the output of the amplifier to the antenna as much as possible, only the phase shifter may be used as the phased array antenna 105 and the wide directional antenna 107 as shown in FIG.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (8)

Distributing means for distributing the input signal to a plurality of signals;
At least one phase shifting means for changing the phase of at least one of the plurality of signals;
A plurality of amplification means for amplifying the power of the plurality of signals;
For each of the plurality of signals whose power is amplified by the amplifying unit, the signals are output to a plurality of antennas corresponding to the plurality of amplifying units, or the plurality of signals are combined and output to at least one antenna. A plurality of switching means for switching whether to output to the combiner;
Control means for controlling the amount of the phase changed by the at least one phase shift means based on the output destinations of the plurality of signals by the plurality of switching means;
A wireless communication apparatus comprising:   When the control means outputs each of the plurality of signals to a plurality of antennas corresponding to the amplification means, a directivity direction formed by sending signals from the plurality of antennas becomes a predetermined direction. The wireless communication apparatus according to claim 1, wherein the amount of the phase changed by the at least one phase shifter is controlled.   The control means, for each of the plurality of signals, when the signal is output to the combiner, the at least one of the plurality of signals output to the combiner is substantially in phase. The radio communication apparatus according to claim 1, wherein the phase amount changed by the phase shift means is controlled. A plurality of conversion means for converting a center frequency for the plurality of signals belonging to the intermediate frequency band;
4. The wireless communication apparatus according to claim 1, wherein the phase shift section changes a phase of the plurality of signals belonging to the intermediate frequency band. 5. Distributing means for distributing the input signal belonging to the baseband or intermediate frequency band to a plurality of signals;
A plurality of conversion means for converting the center frequency of the plurality of signals using any one of a plurality of local signals obtained by distributing from one local signal;
At least one phase shifting means for changing the phase of at least one of the plurality of local signals;
A plurality of amplification means for amplifying the power of the plurality of signals;
For each of the plurality of signals whose power has been amplified by the amplification means, output to a plurality of antennas corresponding to each of the plurality of amplification means, or combine the plurality of signals and output to at least one antenna A plurality of switching means for switching whether to output to the synthesizer,
Control means for controlling the amount of the phase changed by the at least one phase shift means based on the output destinations of the plurality of signals by the plurality of switching means;
A wireless communication apparatus comprising: Distributing means for distributing an input signal to a plurality of signals, at least one phase shifting means for changing the phase of at least one of the plurality of signals, and amplifying the power of the plurality of signals A signal transmission method in a wireless communication device comprising a plurality of amplification means,
A plurality of switching means outputs each of the plurality of signals whose power is amplified by the amplification means to a plurality of antennas corresponding to each of the plurality of amplification means, or combines the plurality of signals. Switching between output to a combiner that outputs to at least one antenna;
A control unit controlling the amount of the phase changed by the at least one phase shift unit based on output destinations of the plurality of signals by the plurality of switching units;
A transmission method characterized by comprising: Distribution means for distributing an input signal belonging to the baseband or intermediate frequency band to a plurality of signals, and a plurality of local signals obtained by distributing the center frequency of the plurality of signals from one local signal, A plurality of conversion means for converting using any one of the above, at least one phase shift means for changing the phase of at least one of the plurality of local signals, and amplifying the power of the plurality of signals A plurality of amplification means, and a signal transmission method in a wireless communication device comprising:
A plurality of switching means outputs each of the plurality of signals whose power is amplified by the amplification means to a plurality of antennas corresponding to each of the plurality of amplification means, or combines the plurality of signals. Switching between output to a combiner that outputs to at least one antenna;
A control unit controlling the amount of the phase changed by the at least one phase shift unit based on output destinations of the plurality of signals by the plurality of switching units;
A transmission method comprising:   The program for functioning a computer as each means with which the radio | wireless communication apparatus of any one of Claim 1 to 5 is provided.

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