JP2005072749A - Radio system and communication method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a speedy and stable radio system by estimating the state of a communication path, based on the transmission/reception antenna gain and the propagation loss of a communication system, and selecting a communication system based on it; and to achieve a communication system using the radio system. <P>SOLUTION: The radio system comprises a first communication system 101 equipped with a direction estimation circuit 107a for estimating the arrival direction of reception radio waves, and an antenna gain calculation circuit 108a for calculating the reception antenna gain based on the estimated arrival direction; and a second communication system 102 equipped with a direction estimation circuit 107b for estimating the arrival direction of radio waves transmitted from the first communication system 101, an antenna gain calculation circuit 108b for calculating the gain of the transmission antenna based on the estimated arrival direction, a propagation loss calculation circuit 110 for calculating the propagation loss of carriers based on the two antenna gains, and a communication system selection circuit 111 for selecting a communication system by estimating the state of the communication path based on the two antenna gains and the propagation loss. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to a radio system including a plurality of communication apparatuses that perform communication by switching a plurality of communication methods in a communication apparatus that performs communication using UHF band to millimeter wave band signals as carrier waves, and a communication method using the same. About.

  In recent years, with the rapid expansion of Internet services, there has been an increasing demand for mobile Internet services using wireless communication devices. Specific examples include services using mobile phones, indoors and offices such as offices and stores, Wireless access where people gather. In addition, communication between fixed stations using radio typified by an FWA (Fixed Wireless Access) system can be said to be a mobile Internet service with a very slow moving speed when considered as a service that can be easily installed, removed, and relocated.

  For these services, development and commercialization of devices using various frequencies such as 800MHz band and 1.5GHz band mobile phones and 2.4GHz band or 5GHz band ISM band (Industry Science Medical Band) It is being advanced.

FIG. 4 shows an example of a multimode wireless communication converter capable of switching between a plurality of communication systems (for example, see Patent Document 1). This multi-mode converter has a selectable multiple or multiband antenna 1401, an antenna duplexer 1402, and a local synthesizer 1404 capable of oscillation at a plurality of oscillation frequencies selectable by a plurality of VCOs (1 to n) 1403. Then, using one oscillation frequency selected from the plurality of oscillation frequencies, a transmission mixer 1405 and a reception mixer 1412 that perform frequency conversion of the first input signal, and a second input signal are selected from a plurality of communication systems. A modulation unit 1406 that modulates and demodulates the signal so as to correspond to a single communication system, a demodulation unit 1411, a specific modulation unit 1413 that modulates and demodulates the third input signal to correspond to the specific communication system, and a specific demodulation unit 1419. ing. Furthermore, it has a software memory 1407, a memory 1408, a software 1409, and a control unit 1410, and an optimum communication frequency band is selected by switching the VCO in the local synthesizer 1404 by a switching command 1423 from the control unit 1410. In addition, the modulation / demodulation method corresponding to each frequency band is switched by selecting the software 1409.
JP 2000-269848 A

  As described in the prior art, in order to perform communication with a plurality of communication systems, attempts have been made to perform communication by switching between 2.4 GHz band and 5 GHz band, or other systems having lower frequency bands. As the switching determination information, the received power level itself or the demodulated signal level is used, and a communication path that changes from time to time cannot be predicted. Therefore, an optimal communication method cannot be selected.

  The present invention estimates the state of a communication path based on a transmission / reception antenna gain and a propagation path loss of a communication device, and selects a communication method based on this, thereby enabling a high-speed and stable wireless system and communication using the same The aim is to realize the method.

In order to solve this problem, the present invention calculates the antenna gain of the transmission antenna and the reception antenna based on the arrival direction of the received radio wave, and calculates the propagation loss of the carrier wave between the communication devices from the transmission power and the reception power. Thus, the state of the communication path is estimated, and based on this, a radio system that performs communication by switching the optimum carrier frequency or modulation / demodulation method and a communication method using the same are configured.

  As a result, communication can be performed by switching to a communication method suitable for the state of the communication path, and a high-speed and stable wireless system can be realized.

  As described above, according to the present invention, the antenna gains of the transmission antenna and the reception antenna are calculated based on the arrival direction of the received radio wave, and the propagation loss of the carrier wave between the communication devices is calculated from the transmission gain and the reception power. Thus, it is advantageous in that a stable wireless system can be realized at low cost at high speed by estimating the state of the communication path and performing communication by switching the optimum communication method, for example, the carrier frequency or the modulation / demodulation method, based on this. An effect is obtained.

  According to a first aspect of the present invention, there is provided first direction estimation means for estimating an arrival direction of a received radio wave, and a first antenna gain based on the arrival direction of the received radio wave estimated by the first direction estimation means. A first communication device comprising a first antenna gain calculating means for calculating a first direction, a second direction estimating means for estimating an arrival direction of a radio wave transmitted from the first communication device, and the second direction. Second antenna gain calculating means for calculating a second antenna gain based on the direction of arrival of the radio wave estimated by the estimating means, and based on the first antenna gain and the second antenna gain. A propagation loss calculating means for calculating a propagation loss until the carrier wave transmitted from the first communication device reaches the second communication device; the first antenna gain; the second antenna gain; and the propagation loss. Based on the And a communication system selection means for selecting a communication system, and a wireless system characterized by comprising: a communication path state by calculating a gain and a transmission loss of a transmission / reception antenna; And a high-performance wireless system can be realized at low cost by selecting an optimal communication method based on this.

  Further, according to a second invention, in the first invention, the communication system selection means selects a communication system using temporal changes of the first antenna gain, the second antenna gain, and the propagation loss. A high-performance wireless system at low cost by estimating the change in the communication path based on the time change in the state of the communication path and selecting the optimal communication method based on this. Can be realized.

  According to a third invention, in the first or second invention, the first communication device and the second communication device communicate with each other using a carrier wave in at least two frequency bands. The wireless system is characterized by selecting a carrier frequency according to the state of the communication path from the at least two frequency bands as a communication method, and differs by estimating the state of the communication path and switching the frequency of the carrier A high-performance wireless system can be realized by properly using communication with different propagation characteristics, different communication areas, and different transmission bands.

  Furthermore, a fourth invention is characterized in that, in the third invention, at least one of the frequency bands of the at least two carrier waves is a frequency band of 20 GHz to 70 GHz or a frequency band of 6 GHz or less. Since the wavelength is short, the antenna can be miniaturized, and since the usable frequency band is wide, the frequency band of 20 to 70 GHz suitable for broadband large-capacity communication, the propagation loss is small, and not only the direct wave but also the reflected wave A high-performance wireless system can be realized by selectively using a frequency band of 6 GHz or less that can be communicated by diffracted waves and has a wide communication area.

  In particular, as in the fifth invention, the fourth invention uses a carrier wave of 24.75 GHz to 25.25 GHz or 26.75 to 27.25 GHz as a carrier wave in the frequency band of 20 GHz to 70 GHz. It is preferable to use a wireless system.

  The sixth invention is characterized in that, in the first or second invention, the first communication device and the second communication device communicate with each other using a signal using a spread spectrum code. It is a wireless system, and it is possible to select the optimal communication method by calculating the distance between communication devices and estimating the state of the communication path more accurately by communicating with signals using spread spectrum codes It becomes possible, and a high-performance wireless system can be realized at low cost.

  According to a seventh invention, in the first or second invention, the first communication device and the second communication device communicate with each other by at least two modulation / demodulation methods, and the communication method selection means is a communication device. A wireless system characterized by selecting a modulation / demodulation method according to the state of the communication path from the at least two modulation / demodulation methods as a method, estimating the state of the communication path, and switching the modulation / demodulation method, By using communication with different delay characteristics, a high-performance wireless system can be realized.

  In particular, as in the eighth invention, in the seventh invention, it is preferable that at least one of the at least two modulation / demodulation systems is a QAM system or a 16QAM system. .

  According to a ninth aspect of the present invention, there is provided a communication method using a wireless system configured by using a first communication device that is a terminal station and a second communication device that is a base station. A survey request step in which the first communication device transmits a survey request signal to the second communication device; and the second communication device receives the survey request signal and transmits a transmission voltage Pt to the first communication device. A response step of transmitting a response signal, and a first direction estimating step in which the first communication device receives the response signal and calculates a reception voltage Pr and estimates a direction of the second communication device; A first antenna gain calculating step in which the first communication device calculates a first antenna gain Gr, which is an antenna gain in the first communication device, using the received voltage Pr; and the first communication device. Is received voltage Pr with respect to the second communication device. And a reception information transmission step for outputting the first antenna gain Gr, a second direction estimation step for the second communication device to estimate a direction of the first communication device, and the first communication. A second antenna gain calculating step of calculating a second antenna gain Gt, which is an antenna gain in the second communication device, using the transmission voltage Pt; and Transmission loss d of a carrier wave in communication between the first communication device and the second communication device using Pt, the second antenna gain Gt, the reception voltage Pr, and the first antenna gain Gr. A transmission loss calculating step for calculating the transmission loss, and the second communication device using the transmission voltage Pt, the second antenna gain Gt, the reception voltage Pr, the first antenna gain Gr, and the transmission loss d. Communication path A communication method selection step for estimating a state and selecting a communication method, and a communication method using a wireless system, estimating a state of a communication path by calculating a gain and a transmission loss of a transmission / reception antenna, and based on this By selecting an optimal communication method, a high-performance wireless system can be realized at low cost.

  Furthermore, a tenth aspect of the invention is the ninth aspect of the invention, wherein the first communication device and the second communication device communicate with each other using carrier waves in at least two frequency bands, and the communication method selection step includes a communication method. As a communication method using a wireless system characterized by selecting a carrier frequency according to the state of the communication path from the at least two frequency bands, by estimating the state of the communication path and switching the frequency of the carrier A high-performance wireless system can be realized by properly using different propagation characteristics, different communication areas, and different transmission band communications.

  Furthermore, an eleventh invention is the radio system according to the tenth invention, wherein at least one of the frequency bands of the at least two carrier waves is a frequency band of 20 GHz to 70 GHz or a frequency band of 6 GHz or less. This is a communication method using an antenna, which can be miniaturized because the wavelength is short, and can be used in a frequency band of 20 to 70 GHz suitable for broadband large-capacity communication because of a wide usable frequency band. In addition to communication using reflected waves and diffracted waves, a high-performance wireless system can be realized by selectively using a wide frequency band of 6 GHz or less with a wide communication area.

  In particular, as in the twelfth aspect, in the eleventh aspect, a carrier wave of 24.75 GHz to 25.25 GHz or 26.75 to 27.25 GHz is used as the carrier wave in the frequency band of 20 GHz to 70 GHz. It is preferable to use a communication method using a wireless system.

  In a thirteenth aspect based on the ninth aspect, the first communication device and the second communication device communicate with each other using a signal using a spread spectrum code. Select the optimal communication method by calculating the distance between communication devices and estimating the state of the communication path more accurately by communicating with signals using spread spectrum codes. And a high-performance wireless system can be realized at low cost.

  In a fourteenth aspect based on the ninth aspect, the first communication device and the second communication device communicate with each other by at least two modulation / demodulation methods, and the communication method selection step includes the communication method as the communication method. It is a communication method using a wireless system characterized by selecting a modulation / demodulation method according to the state of the communication path from at least two modulation / demodulation methods. The reception method is different by estimating the state of the communication path and switching the modulation / demodulation method. By using communication with different sensitivity and different delay characteristics, a high-performance wireless system can be realized.

  In particular, as in the fifteenth aspect, in the fourteenth aspect, at least one of the at least two modulation / demodulation schemes is a QAM scheme or a 16QAM scheme. Is preferred.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram of a communication device used in the wireless system of the present invention, and FIG. 2 is a flowchart of communication method switching. In the present embodiment, the wireless system includes a first communication device 101 and a second communication device 102. The first and second communication devices 101 and 102 are large, and antennas 103a and 103b and a wireless unit 104a. , B, modulation / demodulation units 105a, 105b, and processing units / terminals 106a, 106b.

  The first communication device 101 receives the signal transmitted from the second communication device 102, estimates the direction of the second communication device 102 by the direction estimation circuit 107a in the processing unit / terminal 106a, and calculates the antenna gain. The reception antenna gain Gr when the signal is received from the direction of the second communication device 102 by the circuit 108a is calculated, and the value of the reception antenna gain Gr is transmitted to the second communication device together with the value of the reception power Pr.

The second communication device 102 calculates the transmission antenna gain Gt of its own station based on the signal transmitted to the first communication device 101 in the same manner as the first communication device 101. Further, in the second communication device 102, the propagation loss calculation circuit 110 uses the antenna gain Gr and the reception power Pr sent from the first communication device, and the antenna gain Gt and the transmission power Pt of the own station, between the communication devices. The propagation loss d is calculated, and the first communication device 101 and the second communication device 102 are calculated based on the transmission antenna gain Gt, the reception antenna gain Gr, the propagation loss d, and the time change in the communication method selection circuit 111. Is predicted, the optimum carrier frequency is selected, and the wireless unit 104b is instructed to perform communication at the selected carrier frequency.

  The communication system switching flowchart of FIG. 2 shows an example in which the 25 GHz band and the 5 GHz band are used as the carrier frequency.

  The advantage of using the 25 GHz band as the carrier frequency (hereinafter referred to as 25 G mode) is that if, for example, 24.75 GHz to 25.25 GHz or 26.75 to 27.25 GHz is used, the band of 500 MHz can be used. Thus, high-speed communication using a wide band is possible.

  Moreover, since the wavelength is as short as 1/10 or less compared with 2 GHz or less used in general microwave band communication, for example, an antenna having sharp directivity can be realized in a small size.

  On the other hand, when the 5 GHz band is used as the carrier frequency (hereinafter referred to as 5G mode), it is possible to use highly versatile components used in, for example, IEEE 802.11a or HiSWANa compliant equipment. Can be realized at low cost.

  In addition, the propagation loss at the same distance is smaller than that of a 25 GHz band carrier wave, and communication is possible using not only direct waves but also reflected waves and diffracted waves, so that a wide communication area can be secured. .

  The flowchart will be described with the first communication device 101 of FIG. 1 as a terminal station and the second communication device 102 as a base station. The terminal station makes a communication request to the base station in the 5G mode (201). The base station returns permission / non-permission in the 5G mode (202). The reason why the 5G mode is used here is because the communication area is more important than the communication speed. The terminal station determines whether or not the communication is permitted (203). If the permission is obtained, the communication state is first checked (204).

  The terminal station transmits an investigation request to the base station in the 5G mode (205), and in response thereto, a signal is transmitted from the base station with transmission power Pt (206), and the terminal station receives this signal (received power). Pr), the direction of the signal is estimated by the direction estimation circuit 107a (207), and the reception antenna gain Gr is calculated by the antenna gain calculation circuit 108a (208).

  The base station receives the signal from the terminal station, estimates the direction of the signal by the direction estimation circuit 107b (209), and calculates the transmission antenna gain Gt by the antenna gain calculation circuit 108b (210).

  As a method for estimating the direction of the signal, there are a method for comparing phase differences of signals received by a plurality of antennas and a method for comparing received power.

  If it is possible to change the antenna directivity, the terminal station determines whether the terminal direction is appropriate (211). If not, the terminal corrects the direction (212), and again receives the antenna gain. Gr is calculated.

  In the base station, based on the transmission power Pt of the local station, the reception voltage Pr of the terminal station, the transmission antenna gain Gt of the local station and the reception antenna gain Gr of the terminal station, the propagation loss d of the signal is transmitted by the propagation loss calculation circuit 110. Is calculated (214).

  As a method for calculating the propagation loss d, the following equation may be used. It is also possible to reduce the calculation time by creating a table calculated based on this formula in advance.

Propagation loss calculation formula:
Propagation loss d
= Transmission power Pt-Reception power Pr + Transmission antenna gain Gt + Reception antenna gain Gr.

  Next, the base station determines the communication mode with the received power Pr of the terminal station. Although the estimation of the communication path so far has been performed in the 5G mode, since the positional relationship between the base station and the terminal station can be estimated, the communication state when communicating in the 25G mode can be estimated. Based on this, the communication method selection circuit 111 determines the communication state when communication is performed in the 25G mode based on the received power Pr (215). Communication is performed in the mode (216).

  Finally, based on the transmission antenna gain Gt, the reception antenna gain Gr, the propagation loss value d, and the time change thereof, the communication mode selection circuit 111 estimates the state and change of the communication path, and selects the communication mode. (217). Here, an example is shown in which the following three states are estimated and each communication mode is selected.

[Case 1]
: The antenna gain is large. Propagation loss is small. Small or temporary changes in antenna gain and propagation loss over time.
→ The communication path is stable. High-speed communication is performed in 25G mode. Note that the temporary change is determined to be an instantaneous disconnection of the line, and communication in the 25G mode is maintained (218).

[Case 2]
: Regardless of antenna gain and propagation loss, time change is continuously large.
→ Judged that the communication path has changed drastically, such as the terminal station moving,
Stable communication is performed in the 5G mode with a wide communication area (219).

[Case 3]
: The antenna gain is large. Propagation loss is also large. Time change is small.
→ In order to confirm the possibility of a null point due to multipath, communication is performed using a plurality of channels in the 25G mode (220), and the received power level P′r is confirmed (221). If the received power level is sufficient, the 25G mode is selected (222). If the received power level is insufficient, the base station and the terminal station are determined to be far away, and the 5G mode is selected.
Stable communication is performed in the 5G mode with a wide communication area (223).

  With the above configuration and communication method selection flow, a wireless system capable of stable, high-speed communication at low cost is realized by estimating the state and change of the communication path and selecting the optimum carrier frequency. it can.

  It is also possible to measure the signal delay by communicating with a signal using a spread spectrum code, estimate the distance between the communication devices based on this, and use it as a parameter to replace or supplement the propagation loss. Good.

(Embodiment 2)
FIG. 3 shows a flowchart when the modulation / demodulation method is switched as the communication method. The difference from the first embodiment is that the modulation / demodulation method is switched instead of the carrier frequency based on the state of the communication path and the estimation of the change.

  In the present embodiment, an example of switching between 16QAM and QAM is shown as a modulation / demodulation method.

  When 16QAM is used as a modulation / demodulation method (hereinafter referred to as 16QAM mode), data can be transmitted / received at a communication speed four times that when QAM is used (hereinafter referred to as QAM mode). In particular, it is easily affected by noise when demodulating a received signal, requires a larger S / N ratio than the QAM mode, and needs to receive a larger carrier signal.

  The flowchart will be described with the first communication device 101 of FIG. 1 as a terminal station and the second communication device 102 as a base station. The terminal station makes a communication request to the base station in the QAM mode (301). The base station returns permission / non-permission in the QAM mode (302). The QAM mode is used here because the communication area is more important than the communication speed. The terminal station determines whether or not the communication is permitted (303). If the permission is obtained, the communication state is first checked (304).

  The terminal station transmits a survey request to the base station in the QAM mode (305), and in response thereto, a signal is transmitted from the base station with transmission power Pt (306), and the terminal station receives this signal (received power). Pr), the direction of the signal is estimated by the direction estimation circuit 107a (307), and the reception antenna gain Gr is calculated by the antenna gain calculation circuit 108a (308).

  The base station receives the signal from the terminal station, estimates the direction of the signal by the direction estimation circuit 107b (309), and calculates the transmission antenna gain Gt by the antenna gain calculation circuit 108b (310).

  If it is possible to change the antenna directivity, the terminal station determines whether or not the terminal direction is appropriate (311). If not, the terminal corrects the direction (312), and again receives the antenna gain. Gr is calculated.

  In the base station, based on the transmission power Pt of the local station, the reception voltage Pr of the terminal station, the transmission antenna gain Gt of the local station and the reception antenna gain Gr of the terminal station, the propagation loss d of the signal is transmitted by the propagation loss calculation circuit 110. Is calculated (314).

  Next, the base station determines the communication mode with the received power Pr of the terminal station. The communication path estimation so far has been performed in the QAM mode, but since the positional relationship between the base station and the terminal station can be estimated, the communication state when communicating in the 16QAM mode can be estimated. Based on this, the communication mode selection circuit 111 determines the communication state when communicating in the 16QAM mode based on the received power Pr (315). If the received power Pr is low, the QAM mode with a wide communication area is determined. (316).

  Finally, based on the transmission antenna gain Gt, the reception antenna gain Gr, the propagation loss value d, and the time change thereof, the communication mode selection circuit 111 estimates the state and change of the communication path, and selects the communication mode. (317). Here, an example is shown in which the following three states are estimated and each communication mode is selected.

[Case 1]
: The antenna gain is large. Propagation loss is small. Small or temporary changes in antenna gain and propagation loss over time.
→ The communication path is stable. High-speed communication is performed in 16QAM mode. In addition,
The temporary change is determined as an instantaneous interruption of the line, and communication in the 16QAM mode is maintained (318).

[Case 2]
: Regardless of antenna gain and propagation loss, time change is continuously large.
→ Judged that the communication path has changed drastically, such as the terminal station moving,
Stable communication is performed in the QAM mode with a wide communication area (319).

[Case 3]
: The antenna gain is large. Propagation loss is also large. Time change is small.
→ In order to confirm the possibility of a null point due to multipath, communication is performed using a plurality of channels in the 16QAM mode (320), and the reception power level P′r is confirmed (321). If the received power level is sufficient, the 16QAM mode is selected (322). If the received power level is insufficient, the base station and the terminal station are determined to be far away, and the QAM mode is selected.
Stable communication is performed in the QAM mode with a wide communication area (323).

  With the above configuration and communication method selection flow, a wireless system capable of stable and high-speed communication at low cost is realized by estimating the state and change of the communication path and selecting the optimal modulation / demodulation method. it can.

  In the above description, an example in which QAM and 16QAM are switched and used as the modulation / demodulation method has been shown. The same effect can be obtained even when these are used in combination with 64QAM capable of communication.

  The wireless system according to the present invention calculates the antenna gain of the transmission antenna and the reception antenna based on the arrival direction of the received radio wave, and calculates the propagation loss of the carrier wave between the communication devices from this, the transmission power, and the reception power. By estimating the state of the communication path and performing communication by switching the optimum communication method, for example, the carrier frequency or the modulation / demodulation method based on this, it is possible to realize an advantageous effect that it is possible to realize a low-speed, high-speed and stable wireless system. A communication device that performs communication using a UHF band to millimeter wave band signal as a carrier, for example, a wireless system that includes a plurality of communication devices that perform communication by switching communication methods such as a plurality of carrier frequencies or modulation / demodulation methods, etc. Applicable to usage.

The block diagram of the radio | wireless system by one embodiment of this invention Communication system switching flowchart according to an embodiment of the present invention Communication system switching flowchart according to an embodiment of the present invention Block diagram of a conventional multi-mode communication device

Explanation of symbols

101 First communication device 102 Second communication device 103a, 103b Antenna 104a, 104b Radio unit 105a, 105b Modulation / demodulation unit 106a, 106b Processing unit / terminal 107a, 107b Direction estimation circuit 108a, 108b Antenna gain calculation circuit 109a, 109b Data Processing 110 Propagation loss calculation circuit 111 Communication system selection circuit

Claims (15)

First direction estimating means for estimating a direction of arrival of a received radio wave;
First antenna gain calculating means for calculating a first antenna gain based on the direction of arrival of the received radio wave estimated by the first direction estimating means;
A first communication device comprising:
Second direction estimating means for estimating an arrival direction of the radio wave transmitted from the first communication device;
Second antenna gain calculating means for calculating a second antenna gain based on the direction of arrival of the radio wave estimated by the second direction estimating means;
Propagation loss calculating means for calculating a propagation loss until a carrier wave transmitted from the first communication device reaches the second communication device based on the first antenna gain and the second antenna gain. When,
A communication system selection means for selecting a communication system by estimating a state of a communication path based on the first antenna gain, the second antenna gain, and the propagation loss;
A wireless system characterized by comprising a second communication device having 2. The radio system according to claim 1, wherein the communication system selection unit selects a communication system using a time change of the first antenna gain, the second antenna gain, and the propagation loss. The first communication device and the second communication device communicate with each other using carrier waves in at least two frequency bands, and the communication method selection unit responds to a state of a communication path from the at least two frequency bands as a communication method. 3. The radio system according to claim 1, wherein the carrier frequency is selected. The wireless system according to claim 3, wherein at least one of the frequency bands of the at least two carrier waves is a frequency band of 20 GHz to 70 GHz or a frequency band of 6 GHz or less. The radio system according to claim 4, wherein a carrier wave of 24.75 GHz to 25.25 GHz or 26.75 to 27.25 GHz is used as the carrier wave of the frequency band of 20 GHz to 70 GHz. The wireless system according to claim 1 or 2, wherein the first communication device and the second communication device communicate with each other using a signal using a spread spectrum code. The first communication device and the second communication device communicate with each other by at least two modulation / demodulation schemes, and the communication scheme selection unit modulates / demodulates the communication scheme from the at least two modulation / demodulation schemes according to the state of the communication path. The radio system according to claim 1 or 2, wherein a system is selected. 8. The radio system according to claim 7, wherein at least one of the at least two modulation / demodulation schemes is a QAM scheme or a 16QAM scheme. A communication method using a wireless system configured using a first communication device that is a terminal station and a second communication device that is a base station,
An investigation request step in which the first communication device transmits an investigation request signal to the second communication device, and the second communication device receives the investigation request signal and transmits a transmission voltage to the first communication device. A response step of transmitting a response signal at Pt;
A first direction estimating step in which the first communication device receives the response signal, calculates a reception voltage Pr, and estimates a direction of the second communication device;
A first antenna gain calculating step in which the first communication device calculates a first antenna gain Gr, which is an antenna gain in the first communication device, using the received voltage Pr;
A reception information transmission step in which the first communication device outputs the reception voltage Pr and the first antenna gain Gr to the second communication device;
A second direction estimating step in which the second communication device estimates the direction of the first communication device;
A second antenna gain calculating step in which the first communication device calculates a second antenna gain Gt, which is an antenna gain in the second communication device, using the transmission voltage Pt;
The second communication device uses the transmission voltage Pt, the second antenna gain Gt, the reception voltage Pr, and the first antenna gain Gr to use the first communication device and the second communication device. A transmission loss calculation step of calculating a carrier transmission loss d in communication with
The second communication device estimates a communication path state using the transmission voltage Pt, the second antenna gain Gt, the reception voltage Pr, the first antenna gain Gr, and the transmission loss d, and performs communication. A communication method selection step for selecting a method;
A communication method using a wireless system. The first communication device and the second communication device communicate with each other using carrier waves in at least two frequency bands, and the communication method selection step corresponds to a state of a communication path from the at least two frequency bands as a communication method. 10. A communication method using a wireless system according to claim 9, wherein the carrier frequency is selected. The communication method using a wireless system according to claim 10, wherein at least one of the frequency bands of the at least two carrier waves is a frequency band of 20 GHz to 70 GHz or a frequency band of 6 GHz or less. The communication method using a wireless system according to claim 11, wherein a carrier wave of 24.75 GHz to 25.25 GHz or 26.75 to 27.25 GHz is used as the carrier wave of the frequency band of 20 GHz to 70 GHz. The communication method using a wireless system according to claim 9, wherein the first communication device and the second communication device communicate with each other using a signal using a spread spectrum code. The first communication device and the second communication device communicate with each other by at least two modulation / demodulation methods, and the communication method selection step includes modulation / demodulation according to the state of a communication path from the at least two modulation / demodulation methods as communication methods. The communication method using the wireless system according to claim 9, wherein a method is selected. 15. The communication method using a radio system according to claim 14, wherein at least one of the at least two modulation / demodulation schemes is a QAM scheme or a 16QAM scheme.

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