JP4955324B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system having a radio transmitter and a radio receiver suitable for transmitting signals at high speed.

  In digital wireless communication, as a method for transmitting a signal at high speed, (1) a method for increasing a symbol rate or (2) a method for performing multilevel modulation is generally used. However, (1) in order to increase the symbol rate, it is necessary to operate digital circuits such as A / D converters and D / A converters at high speeds and to increase the bandwidth of baseband circuits. Or power consumption increases significantly. On the other hand, when the latter (2) multilevel modulation is performed, the load on the digital circuit and the baseband circuit is reduced, but the envelope of the modulated signal fluctuates, and the ratio of the peak power to the average power of the signal ( PAPR: Peak to Average Power Ratio) increases. In order to linearly amplify such a signal with a large PAPR, it is necessary to use an amplifier having a large saturation output and operate with sufficient back-off from the saturation output. In the amplifier to be used, there is a problem that the efficiency is remarkably lowered. In particular, in a communication system in the microwave or millimeter wave region where it is difficult to realize a high-output and high-efficiency amplifier, the transmitter is expensive and the efficiency is remarkably lowered, resulting in the need for an expensive heat dissipation device. Problems such as becoming.

  Furthermore, there is a method using multicarrier as another method for high-speed transmission by wireless communication. FIG. 11 is a block diagram illustrating a configuration of a conventional wireless transmission device using multicarrier (see, for example, Patent Document 1).

  The conventional wireless transmission device shown in FIG. 11 has a data input unit 101 to which an input digital signal is serially input, and a plurality of serial input digital signals input to the data input unit 101 are received by a serial / parallel converter 102. Are converted into parallel channels, and the converted digital signal of each channel is encoded by the convolutional encoder 103. This convolutionally encoded digital signal is subjected to multilevel modulation by a modulator 104. The multi-level modulated signal is converted into a plurality of signals having different carrier frequencies by the frequency converters 105a to 105d, further synthesized by the multiplexer 106, and then wirelessly transmitted from the antenna 107.

  In such a conventional wireless transmission device, since the carrier frequencies of the wirelessly transmitted signals are separated from each other, it is unlikely that signals of adjacent frequencies will be lost simultaneously due to fading, and a convolutionally encoded signal is used. Therefore, even if a part of the signal is lost, it can be restored, and a radio apparatus with good communication quality can be realized even in a fading environment.

  Although not specifically shown in the block diagram of the conventional wireless transmission apparatus in FIG. 11, when the apparatus is actually configured, it is considered necessary to obtain power necessary for wireless transmission by an amplifier. In this case, an amplifier 108 is inserted after each of the frequency converters 105a to 105d as shown in FIG. 12 (a), or one amplifier is interposed between the multiplexer 106 and the antenna 107 as shown in FIG. 12 (b). It is conceivable to insert an amplifier 108. However, in both cases of FIG. 12A and FIG. 12B, since a multi-level modulated signal is used, a signal with a large PAPR in which the envelope of the signal fluctuates is input to the amplifier 108. For this reason, it is necessary to use the amplifier 108 having a large saturated output, and there is a problem that the efficiency of the amplifier 108 is lowered because it is used by taking back-off from the saturated output level.

  FIG. 13 is a block diagram showing a configuration of another conventional wireless transmission device using multicarrier (see, for example, Patent Document 1).

  In another conventional wireless transmission apparatus shown in FIG. 13, an input digital signal is divided into a plurality of channels, and the digital signal of each channel is modulated using a modulator 104, and further, different carriers are used in frequency converters 105a to 105d. Frequency converted to frequency. Signals frequency-converted at different carrier frequencies of the respective channels are wirelessly transmitted from a plurality of antennas 107 arranged at a distance of ¼ wavelength or more. In this way, a plurality of antennas 107 that are spaced apart by a quarter wavelength or more are used, and a signal with a different carrier frequency is wirelessly transmitted from each antenna 107, thereby using a receiving device with one receiving antenna. Even in the case, it is possible to obtain the same function as that of space diversity, and to prevent a reduction in communication quality due to fading.

  As described above, the other conventional wireless transmission device shown in FIG. 13 aims to prevent a reduction in communication quality due to fading even when a single reception device is used as a reception antenna. Although not shown in FIG. 13, it is generally necessary to load an amplifier after each of the frequency converters 105a to 105d in order to obtain power necessary for wireless transmission when actually configuring the apparatus. Become. However, as a signal modulation method, a PAPR is increased because a modulation method in which an envelope such as BPSK, ASK, PSK, or multilevel QAM varies is used. For this reason, in order to linearly amplify the signal, it is necessary to use an amplifier having a large saturated output, and there is a problem that the efficiency of the amplifier is lowered because it is used by taking backoff from the saturated output level. Further, in the other conventional wireless transmission device of FIG. 13, since it is an indispensable system to use a plurality of antennas 107 for transmission, problems such as an increase in the number of channels and an increase in the cost of the transmission device occur. .

Japanese Patent No. 3346945

  In the conventional wireless transmission apparatus as described above, when transmitting a signal at high speed, an amplifier having a large saturated output is used as an amplifier to linearly amplify the signal, and the amplifier is used by taking a back-off from the saturated output level. There is a problem that the efficiency of the system becomes low.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a wireless transmission apparatus and a wireless communication apparatus that are highly efficient and easy to configure even when signals are transmitted at high speed. A wireless communication system having a receiving device is obtained.

A radio communication system according to the present invention is a radio communication system for communicating a signal between a radio transmission device and a radio reception device by a multi-carrier in a millimeter wave band, wherein the radio transmission device per symbol of an input digital signal a plurality of n (n is an integer of 2 or more) parallel converter for dividing a serial digital signal composed of data of the plurality of n-channel included in the time T (sec), the split by serial-to-parallel converter The constant envelope modulator provided for each channel that modulates the digital signal by the constant envelope modulation method, and the signal voltage V (t) by the constant envelope modulation method is expressed by equations (1) to (3) described later. In the equations (1) to (3), A is the amplitude (constant value) of the signal, f ₀ is the carrier frequency, t is the time, a is the data, h is a constant, and T is the time per symbol. And A digital signal modulated by the constant envelope modulator is converted to an analog signal, and a D / A converter provided for each channel, and the analog signal converted by the D / A converter is different from other channels. A first frequency converter provided for each channel for frequency conversion to a frequency; an amplifier provided for each channel for amplifying a signal frequency-converted by the first frequency converter with high efficiency; and A transmission antenna provided for each channel that wirelessly transmits the signal amplified by the amplifier to the space, and the wireless reception device includes a single reception antenna that wirelessly receives the signal wirelessly transmitted to the space a demultiplexer for dividing the signals received by said one reception antennas into a signal of each channel having a different carrier frequency, divided by the demultiplexer A second frequency converter provided for each channel that converts the frequency of the received signal to a baseband frequency, and a signal that is converted by the second frequency converter to a digital signal. A / D converter, a constant envelope demodulator provided for each channel for demodulating the digital signal converted by the A / D converter, and a parallel for each channel demodulated by the constant envelope demodulator A parallel-serial converter that restores the digital signal to the original serial digital signal is provided.

  The wireless communication system according to the present invention has an effect that the efficiency of the amplifier is high and the configuration is easy even when a signal is transmitted at high speed.

Embodiment 1 FIG.
A radio communication system according to Embodiment 1 of the present invention will be described with reference to FIG. 1 and FIG. 1 is a diagram showing a configuration of a radio transmission apparatus and a flow of transmission signals in a radio communication system according to Embodiment 1 of the present invention. FIG. 2 is a diagram showing the configuration of the radio reception apparatus and the flow of received signals in the radio communication system according to Embodiment 1 of the present invention. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

  In FIG. 1, a wireless transmission device 10 of the wireless communication system according to the first embodiment includes a serial-parallel converter (first dividing means) 11, a constant envelope modulator 12, a D / A converter 13, Frequency converters (first frequency converting means) 14a, 14b, 14c, 14d, an amplifier (amplifying means) 15, and four transmitting antennas (transmitting means) 19 are provided. The constant envelope modulator 12 and the D / A converter 13 constitute modulation means.

  In FIG. 2, a radio reception apparatus 20 of the radio communication system according to the first embodiment includes one reception antenna (reception means) 21, a duplexer (second division means) 22, and a frequency conversion. (Second frequency conversion means) 23a, 23b, 23c, 23d, an A / D converter 24, a constant envelope demodulator 25, and a parallel-serial converter (restoration means) 26 are provided. The A / D converter 24 and the constant envelope demodulator 25 constitute demodulation means.

  Next, the operation of the wireless communication system according to the first embodiment will be described with reference to the drawings. 1 and 2 also show the flow of transmission / reception signals of a wireless communication system in which an input digital signal is divided into four channels and transmitted / received as an example.

  On the wireless transmission device 10 side, as shown in FIG. 1, the input digital signal is divided into four channels by the serial-parallel converter 11, and the divided signals are respectively modulated by the constant envelope modulator 12.

  Here, the signal voltage V (t) by the constant envelope modulation method is, for example, “CE sundberg,“ Continuous Phase Modulation, ”IEEE Communication Magazine, Vo.24, No.4, pp.25-38, April 1986.” As shown in FIG. 4, the amplitude envelope is given by the following equation.

In the above equations (1) to (3), A is the amplitude (constant value) of the signal, f ₀ is the carrier frequency, t is the time, a is the data, h is a constant, and T is the time per symbol.

  Next, the signals modulated for each channel by the D / A converter 13 are converted into analog signals, and the analog signals of the respective channels are subjected to frequency conversion by frequency converters 14a, 14b, 14c, and 14d having different carrier frequencies. Next, each signal is amplified with high efficiency by the amplifier 15 and sent to the space by the antenna 19.

  On the radio receiver 20 side, as shown in FIG. 2, the signal received by the antenna 21 is divided by the demultiplexer 22 into signals for each channel having different carrier frequencies. Next, the signals separated for each channel are converted into baseband frequencies by frequency converters 23a, 23b, 23c, and 23d, respectively, and digitized by A / D converters 24, respectively. Next, the signal is demodulated by the constant envelope demodulator 25, and the parallel digital signal for each channel is restored to the original serial digital signal by the parallel-serial converter 26.

  This method realizes high speed by performing multi-leveling by hardware, so if it is divided into 4 channels, the multi-level conversion rate in the case of transmission with 1 channel is equivalent to 4 times, Alternatively, it is possible to have a speed equivalent to a symbol rate of 4 times. For this reason, it is possible to reduce problems of high-speed operation of the digital circuit and widening of the baseband circuit, which are adverse effects of high-speed operation by increasing the symbol rate or performing multi-level modulation.

  Furthermore, the reduction in efficiency due to the PAPR problem due to fluctuations in the envelope of the signal, which is a problem in the conventional example of FIGS. 11 and 13 shown in Patent Document 1, can be solved by individually amplifying the constant envelope modulation signal. It is.

  Therefore, it is not necessary to use a high-speed / broadband device, and it is possible to use inexpensive parts in the D / A converter 13, the A / D converter 24, etc., and no PAPR problem occurs. Therefore, the amplifier can be used at a high saturation output level. Accordingly, a wireless communication system capable of low cost, low power consumption, and high speed data transmission can be realized. In particular, in the millimeter wave band where a wide band can be used for wireless communication, it is very expensive and technically difficult to realize a high-performance device. However, the present invention relaxes these requirements. Suitable for waveband wireless communication.

Embodiment 2. FIG.
A radio communication system according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of a radio transmission apparatus of the radio communication system according to Embodiment 2 of the present invention.

  In FIG. 3, the radio transmission apparatus 10 of the radio communication system according to the second embodiment includes a series-parallel converter 11, a constant envelope modulator 12, a D / A converter 13, frequency converters 14a and 14b, 14c and 14d, an amplifier 15, a multiplexer (multiplexing means) 16, and one transmission antenna 19 are provided.

  On the wireless transmission device 10 side, a modulated signal with a different carrier frequency amplified for each channel is multiplexed by a multiplexer 16 and transmitted using a single antenna 19. Thereby, it is not necessary to use a plurality of antennas, and the apparatus can be miniaturized.

Embodiment 3 FIG.
A radio communication system according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of a wireless transmission device of a wireless communication system according to Embodiment 3 of the present invention.

  In FIG. 4, the radio transmission apparatus 10 of the radio communication system according to the third embodiment includes a series-parallel converter 11, a constant envelope modulator 12, a D / A converter 13, frequency converters 14a and 14b, 14c and 14d, a saturation amplifier 15a, a multiplexer 16, and one transmitting antenna 19 are provided.

  On the radio transmitting apparatus 10 side, a saturation amplifier 15a operating at a saturated output level with high efficiency is used as a device corresponding to the amplifier 15 of the first and second embodiments. As a result, the power consumption of the wireless transmission device 10 can be reduced.

Embodiment 4 FIG.
A radio communication system according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of a radio reception apparatus of a radio communication system according to Embodiment 4 of the present invention.

  In FIG. 5, the radio reception apparatus 20 of the radio communication system according to the fourth embodiment includes two reception antennas 21, two duplexers 22, four multiplexers 27, and a frequency. Converters 23a, 23b, 23c, and 23d, an A / D converter 24, a constant envelope demodulator 25, and a parallel-serial converter 26 are provided.

  On the wireless receiver 20 side, wireless reception is performed using two or more receiving antennas 21. For example, in FIG. 5, a signal having four carrier frequencies is wirelessly received using two antennas 21. Shows when to do.

  Each signal wirelessly received by the two antennas 21 is separated by the demultiplexer 22 for each of the four carrier frequencies, and the separated signal for each carrier frequency is multiplexed by the multiplexer 27. . The combined signal of each carrier frequency is converted to a baseband frequency by frequency converters 23a, 23b, 23c, and 23d, and digitized by an A / D converter 24, respectively. Next, the signal is demodulated by the constant envelope demodulator 25, and the parallel digital signal for each channel is restored to the original serial digital signal by the parallel-serial converter 26. With this method, since a plurality of receiving antennas 21 are used, the antenna gain can be increased.

Embodiment 5 FIG.
A radio communication system according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of a radio reception apparatus of the radio communication system according to Embodiment 5 of the present invention.

  In FIG. 6, the wireless reception device 20 of the wireless communication system according to the fifth embodiment includes two (plural) reception antennas 21, a duplexer 22 for each antenna 21, and a frequency for each antenna 21. Converters 23a, 23b, 23c, 23d, A / D converter 24 for each antenna 21, constant envelope demodulator 25 for each antenna 21, weighted adder (weighted addition means) 28, and parallel-serial converter 26 And are provided.

  In the fifth embodiment, the radio reception apparatus 20 also performs radio reception using two or more reception antennas 21. For example, FIG. 6 shows two signals having four carrier frequencies. A case of wireless reception using the reception antenna 21 is shown.

  The respective signals wirelessly received by the two receiving antennas 21 are respectively separated by the demultiplexer 22, the frequency converters 23 a, 23 b, 23 c, 23 d, the A / D converter 24, and the constant envelope demodulator 25. Each carrier frequency is converted into a digital signal. The digital signal received and demodulated by each antenna 21 is added by a weighting adder 28 for each channel corresponding to each antenna 21. The digital signal for each channel subjected to the weighted addition is restored from the parallel digital signal for each channel to the original serial digital signal by the parallel-serial converter 26.

  On the wireless reception device 20 side, the quality of communication can be improved by the diversity function by receiving by two or more antennas 21 and weighting and adding a plurality of digital signals for each channel received by the respective antennas 21.

Embodiment 6 FIG.
A radio communication system according to Embodiment 6 of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing configurations of a radio transmission apparatus and radio reception apparatus of a radio communication system according to Embodiment 6 of the present invention.

  In FIG. 7A, the radio transmission apparatus 10 of the radio communication system according to the sixth embodiment includes a series-parallel converter 11, a constant envelope modulator 12, a D / A converter 13, and a frequency converter 14a. , 14b, 14c, 14d, an amplifier 15, a gain adjustment circuit (gain adjustment means) 17, and four transmission antennas 19 are provided.

  In FIG. 7B, the radio reception apparatus 20 of the radio communication system according to the sixth embodiment includes one reception antenna 21, a duplexer 22, and frequency converters 23a, 23b, 23c, and 23d. An A / D converter 24, a constant envelope demodulator 25, and a parallel-serial converter 26 are provided.

  The gain of the amplifier 15 of each channel on the wireless transmission device 10 side is adjusted by the gain adjustment circuit 17 so that the received power of each channel becomes equal even when there is a large difference in the carrier frequency of each channel. As a result, it is possible to prevent deterioration in communication quality due to variations in received power, and high-quality signal transmission is possible. Information regarding the variation in the received power is obtained from the transmission destination through another wireless line. In the configuration of FIG. 7, the gain of the amplifier 15 on the wireless transmission device 10 side is adjusted to equalize the reception power for each channel. However, the antenna 19 and the wireless reception device 20 have an adjustment function. There may be.

Embodiment 7 FIG.
A radio communication system according to Embodiment 7 of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing a partial configuration of a radio reception apparatus of the radio communication system according to Embodiment 7 of the present invention.

  FIG. 8 shows another configuration example of a circuit portion for frequency separation and frequency conversion in the wireless reception device of the wireless communication system of each embodiment. As in the configuration of FIG. 8, frequency separation and frequency conversion may be performed simultaneously using mixers 31 a, 31 b, 31 c, and 31 d having different local oscillation frequencies and a low-pass filter 32. That is, for example, the duplexer 22 and the frequency converters 23a, 23b, 23c, and 23d of FIGS. 2, 6, and 7B are replaced with the mixers 31a, 31b, 31c, and 31d and the low-pass filter 32. It may be replaced.

Embodiment 8 FIG.
A radio communication system according to Embodiment 8 of the present invention will be described with reference to FIGS. FIG. 9 is a block diagram showing configurations of a radio transmission apparatus and radio reception apparatus of a radio communication system according to Embodiment 8 of the present invention. Moreover, FIG. 10 is a figure which shows the frequency bandwidth of the radio | wireless communications system which concerns on Embodiment 8 of this invention.

  In FIG. 9A, the radio transmission apparatus 10 of the radio communication system according to the eighth embodiment includes a serial / parallel converter (dividing means) 11, a constant envelope modulator 12, a D / A converter 13, Frequency converters (first frequency converting means) 14a ', 14b', 14c ', 14d', amplifier (amplifying means) 15, two multiplexers (multiplexing means) 16, and two for transmission Directivity antennas (first and second transmitting antennas) 19a and 19b are provided. The constant envelope modulator 12 and the D / A converter 13 constitute modulation means.

  In FIG. 9 (b), the wireless reception device 20 of the wireless communication system according to the eighth embodiment includes two reception directional antennas (first and second reception antennas) 21a and 21b, Number of demultiplexers (demultiplexing means) 22, frequency converters (second frequency converting means) 23 a ′, 23 b ′, 23 c ′, 23 d ′, A / D converter 24, and constant envelope demodulator 25 And a parallel-serial converter (restoring means) 26 are provided. The A / D converter 24 and the constant envelope demodulator 25 constitute demodulation means.

  In the eighth embodiment, in addition to the effects described in the above embodiments, effective use of the used frequency band is intended. That is, the frequency occupation bandwidth can be reduced as compared with each of the above embodiments.

  Assuming that the signal bandwidth required per channel (single channel occupation bandwidth) is Bw, the total frequency bandwidth required in each of the above embodiments is 4 Bw ( = Bw × 4 channels) In the eighth embodiment, for example, as shown in FIG. 10B, it can be reduced to 2.5 Bw.

  Next, the operation of the wireless communication system according to the eighth embodiment will be described focusing on differences from the other embodiments described above.

  In FIG. 10B, a signal 41 is a first channel signal frequency-converted by the frequency converter 14a ′ of the wireless transmission device 10, a signal 42 is a second channel signal frequency-converted by the frequency converter 14b ′, The signal 43 is a third channel signal frequency-converted by the frequency converter 14c ′, and the signal 44 is a fourth channel signal frequency-converted by the frequency converter 14d ′.

  The frequency converters 14 a ′, 14 b ′, 14 c ′, and 14 d ′ on the radio transmission device 10 side convert the center frequency of each channel into the frequency positional relationship shown in FIG. Next, the directional antenna 19 a transmits a signal obtained by combining the signal 41 and the signal 43 toward the directional antenna 21 a of the wireless reception device 20. Similarly, the directional antenna 19 b transmits a signal obtained by combining the signal 42 and the signal 44 toward the directional antenna 21 b of the wireless reception device 20.

  These directional antennas 19a and 19b can be controlled by always directing the direction of the antenna toward the transmission destination even when the wireless transmission device 10 or the wireless reception device 20 is moving, for example, by applying a beam forming antenna or the like. Good.

  On the other hand, in the wireless reception device 20, the directional antenna 21a receives a signal from the directional antenna 19a, and the directional antenna 21b receives a signal from the directional antenna 19b. For these directional antennas 21a and 21b, for example, by applying a beam forming antenna or the like, even when the wireless transmission device 10 or the wireless reception device 20 is moving, control is performed so that the direction of the antenna is always directed to the transmission source. Good.

  Next, the signals 41, 42, 43, and 44 extracted by the branching filter 22 are converted into baseband frequencies by frequency converters 23a ′, 23b ′, 23c ′, and 23d ′, respectively, and the A / D converter 24 is used. Is input.

  Thus, in the eighth embodiment, the occupied bandwidth of the frequency can be reduced from 4 Bw to 2.5 Bw. Further, problems that occur at that time include the influence of interference input from the transmission antenna 19b on the main wave from the transmission antenna 19a received by the reception antenna 21a, and the reception antenna. The influence of interference input from the transmission antenna 19a can be considered on the main wave from the transmission antenna 19b received by the antenna 21b. This effect is (1) directional antenna for both transmission and reception. (2) The center frequency of each channel is arranged at the null point of the channel transmitted from another antenna to reduce the frequency.

  In the eighth embodiment, the number of channels is four, but any value may be used as long as the number of channels is two or more. In the eighth embodiment, transmission and reception are directional antennas. However, an antenna having directivity may be only on the transmission side or only on the reception side.

  Furthermore, as described above, in the eighth embodiment, the antenna has directivity as a means for avoiding the influence of interference with the antenna. However, the polarization method of the antennas 19a and 21a and the antennas 19b and 21b These polarization methods may be orthogonal to each other (for example, vertical polarization and horizontal polarization, left turn polarization and right turn polarization), and the influence of interference may be further reduced.

  As described above, the wireless communication system of each of the above-described embodiments enables multi-valued hardware by using a constant envelope modulation system. For this reason, the increase in PAPR can be completely prevented by the constant envelope modulation method, so that the power consumption can be reduced by using a highly efficient amplifier. Further, it is possible to reduce the symbol rate acceleration rate and reduce the load on devices such as A / D converters, D / A converters, filters, and the like, so that the cost of a single device can be reduced. Furthermore, since a single antenna and a plurality of antennas can be properly used according to the system, it is possible to satisfy the needs for downsizing and high quality. As described above, a high-speed wireless communication device can be provided with high performance and low cost.

  Further, in the wireless communication system of the eighth embodiment, in addition to the effects of the wireless communication systems of the first to seventh embodiments, the frequency occupation band can be reduced to about half, and the effect of greatly improving the frequency utilization efficiency is achieved.

It is a figure which shows the structure of the radio | wireless transmission apparatus of the radio | wireless communications system which concerns on Embodiment 1 of this invention, and the flow of a transmission signal. It is a figure which shows the structure of the radio | wireless receiving apparatus of the radio | wireless communications system which concerns on Embodiment 1 of this invention, and the flow of a received signal. It is a block diagram which shows the structure of the radio | wireless transmission apparatus of the radio | wireless communications system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the radio | wireless transmission apparatus of the radio | wireless communications system which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the radio | wireless receiver of the radio | wireless communications system which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the radio | wireless receiving apparatus of the radio | wireless communications system which concerns on Embodiment 5 of this invention. It is a block diagram which shows the structure of the radio | wireless transmission apparatus and radio | wireless receiving apparatus of the radio | wireless communications system which concern on Embodiment 6 of this invention. It is a figure which shows the partial structure of the radio | wireless receiver of the radio | wireless communications system which concerns on Embodiment 7 of this invention. It is a block diagram which shows the structure of the radio | wireless transmission apparatus and radio | wireless receiving apparatus of the radio | wireless communications system which concern on Embodiment 8 of this invention. It is a figure which shows the frequency bandwidth of the radio | wireless communications system which concerns on Embodiment 8 of this invention. It is a block diagram which shows the structure of the conventional radio | wireless transmitter which uses a multicarrier. It is a block diagram which shows another structure of the conventional radio | wireless transmitter which uses a multicarrier. It is a block diagram which shows the structure of the other conventional radio | wireless transmitter which uses a multicarrier.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Radio transmitter, 11 Serial-parallel converter, 12 Constant envelope modulator, 13 D / A converter, 14a, 14b, 14c, 14d Frequency converter, 15 amplifier, 15a Saturation amplifier, 16 multiplexer, 17 Gain adjustment Circuit, 19 antenna, 19a, 19b directional antenna, 20 radio receiver, 21 antenna, 21a, 21b directional antenna, 22 duplexer, 23a, 23b, 23c, 23d frequency converter, 24 A / D converter, 25 constant envelope demodulator, 26 parallel-serial converter, 27 multiplexer, 28 weighted adder.

Claims (7)

A wireless communication system for communicating signals between a wireless transmission device and a wireless reception device by a multi-carrier in the millimeter wave band,
The wireless transmission device
A serial-parallel converter for dividing a serial digital signal composed of a plurality of n (n is an integer of 2 or more) data included in a time T (sec) per symbol of an input digital signal into the n channels;
A constant envelope modulator provided for each channel for modulating the digital signal divided by the serial-parallel converter by a constant envelope modulation method;
Here, the signal voltage V (t) by the constant envelope modulation method is given by the following equations (1) to (3):

In the above formulas (1) to (3), A is the amplitude (constant value) of the signal, f ₀ is the carrier frequency, t is the time, a is the data, h is a constant, and T is the time per symbol.
A D / A converter provided for each channel for converting the digital signal modulated by the constant envelope modulator into an analog signal;
A first frequency converter provided for each channel that converts the analog signal converted by the D / A converter to a carrier frequency different from that of other channels;
An amplifier provided for each channel for amplifying the signal frequency-converted by the first frequency converter with high efficiency;
A wireless transmission of the signal amplified by the amplifier to the space, and a transmission antenna provided for each channel,
The wireless receiver is
One receiving antenna for wirelessly receiving a signal wirelessly transmitted to the space;
A duplexer for dividing a signal received by the one receiving antenna into signals for each channel having different carrier frequencies;
A second frequency converter provided for each channel for frequency-converting the signal divided by the branching filter to a baseband frequency;
An A / D converter provided for each channel for converting the signal frequency-converted by the second frequency converter into a digital signal;
A constant envelope demodulator provided for each channel for demodulating the digital signal converted by the A / D converter;
A wireless communication system comprising: a parallel-serial converter that restores a parallel digital signal for each channel demodulated by the constant envelope demodulator to an original serial digital signal. The wireless transmission device, instead of the transmission antenna provided for each channel,
A multiplexer that multiplexes modulation signals of different carrier frequencies amplified for each channel by the amplifier;
The wireless communication system according to claim 1, further comprising: one transmission antenna that wirelessly transmits a signal combined by the multiplexer. The wireless communication system according to claim 1, wherein the amplifier is a saturation amplifier that operates at a saturation output level. The wireless receiver is configured to replace the one receiving antenna and the duplexer,
A plurality of receiving antennas for wirelessly receiving signals wirelessly transmitted to the space;
A plurality of demultiplexers that respectively demultiplex signals received by the plurality of receiving antennas into different channels for each carrier frequency;
A plurality of multiplexers for respectively multiplexing the signals demultiplexed by the plurality of demultiplexers for each signal of the same carrier frequency,
The second frequency converter provided for each channel converts the signals combined for each channel by the plurality of multiplexers to baseband frequencies, respectively. The wireless communication system described. Instead of the wireless receiver,
A plurality of receiving antennas for wirelessly receiving signals wirelessly transmitted to the space;
A duplexer provided for each receiving antenna, which divides the signals received by the plurality of receiving antennas into signals for each channel having different carrier frequencies;
A second frequency converter provided for each receiving antenna and each channel for frequency-converting the signal divided by the branching filter to a baseband frequency;
An A / D converter provided for each receiving antenna and each channel for converting a signal frequency-converted by the second frequency converter into a digital signal;
A constant envelope demodulator provided for each receiving antenna and each channel for demodulating the digital signal converted by the A / D converter;
A weighted adder provided for each channel for weighted addition of signals for each receiving antenna demodulated by the constant envelope demodulator;
4. The radio receiver according to claim 1, further comprising: a parallel-serial converter that restores the parallel digital signal for each channel weighted by the weighted adder to the original serial digital signal. Wireless communication system. At least one of the wireless transmission device and the wireless reception device is:
The wireless communication system according to any one of claims 1 to 5, further comprising a gain adjustment circuit provided for each channel for adjusting the gain so that the reception power of each channel becomes equal. A wireless communication system for communicating signals between a wireless transmission device and a wireless reception device by a multi-carrier in the millimeter wave band,
The wireless transmission device
Plurality of n included in one symbol per time T (sec) of the input digital signal (n is an integer of 2 or more) and serial-to-parallel converter for dividing a serial digital signal composed of data of the plurality of n-channel,
A constant envelope modulator provided for each channel for modulating the digital signal divided by the serial-parallel converter by a constant envelope modulation method;
Here, the signal voltage V (t) by the constant envelope modulation method is given by the following equations (1) to (3):

In the above formulas (1) to (3), A is the amplitude (constant value) of the signal, f ₀ is the carrier frequency, t is the time, a is the data, h is a constant, and T is the time per symbol.
A D / A converter provided for each channel for converting the digital signal modulated by the constant envelope modulator into an analog signal;
Of the constant envelope modulation signal of the analog signal converted by the D / A converter, the interval between the odd-numbered channels and the interval between the even-numbered channels are set as a single channel occupied bandwidth, and the odd-numbered channel A first frequency converter provided for each channel for converting a difference between the frequency and the frequency of the even-numbered channel into a carrier frequency different from that of the other channel so as to be half of the single channel occupied bandwidth;
An amplifier provided for each channel for amplifying the signal frequency-converted by the first frequency converter with high efficiency;
A first multiplexer for multiplexing the signals amplified by the amplifier for each odd-numbered channel;
A second multiplexer for multiplexing the signal amplified by the amplifier for each even-numbered channel;
A first antenna for transmission that wirelessly transmits a signal of an odd-numbered channel combined by the first multiplexer to space;
A second transmission antenna for wirelessly transmitting the signal of the even-numbered channel combined by the second multiplexer to space;
The wireless receiver is
A first receiving antenna for wirelessly receiving a signal wirelessly transmitted by the first transmitting antenna;
A second receiving antenna for wirelessly receiving a signal wirelessly transmitted by the second transmitting antenna;
A first demultiplexer for demultiplexing a signal received by the first receiving antenna into a different channel for each carrier frequency;
A second duplexer for demultiplexing a signal received by the second receiving antenna into different channels for each carrier frequency;
A second frequency converter provided for each channel for frequency-converting the signal divided by the first and second duplexers to a baseband frequency;
An A / D converter provided for each channel for converting the signal frequency-converted by the second frequency converter into a digital signal;
A constant envelope demodulator provided for each channel for demodulating the digital signal converted by the A / D converter;
A parallel-serial converter for restoring the parallel digital signal for each channel demodulated by the constant envelope demodulator to the original serial digital signal;
The first and second transmitting antennas and the first and second receiving antennas are directional antennas,
A wireless communication system, wherein a center frequency of each channel is arranged at a null point of a channel transmitted from another transmitting antenna.

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