JP3544891B2 - Wireless transmission system and method for determining directivity direction of antenna - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless transmission system and a method for determining a directivity direction of an antenna. In particular, the present invention relates to a communication system that automatically sets an antenna direction for performing wireless transmission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a network system (wireless LAN) using a radio frequency in which each terminal device has a wireless interface has been proposed.
[0003]
In particular, in response to recent demand for high-speed broadband wireless communication, a simple transmission / reception system using an extremely high radio frequency as disclosed in Japanese Patent Application Laid-Open No. 5-304526 has been proposed. JP-A-5-304526 discloses a base station provided with an antenna 801 having a sufficiently wide-angle radiation characteristic, which is mounted at a high position such as a ceiling and directed downward as shown in FIG. And an arbitrary number of terminal stations 803 that exchange data with the parent transceiver, which are placed at a low position, form a premises network. The terminal station 803 has a sufficiently narrow-angle radiation characteristic. An antenna 804 including an antenna 808 is provided, and a layer including a substance 802 that absorbs radio waves in the use frequency band is provided on the ceiling or the like.
[0004]
In this configuration, when the antenna 804 of the terminal station is directed toward the base station antenna 801, the radio wave absorber 802 around the base station antenna absorbs interference and reflected radio waves 806. Since all the interfering waves 807 due to multipaths other than the radio waves 805 are removed, interference and multipath are extremely reduced.
[0005]
[Problems to be solved by the invention]
However, in the above configuration, the transmission / reception device is simple, but the antenna 801 and the larger radio wave absorber 802 must be installed at the center of the ceiling. In addition, only terminals at a position where a wave can reach directly from the position of the antenna 801, that is, a terminal at a line of sight can transmit and receive, and the installation is limited to a room having a very high ceiling or the like.
[0006]
Furthermore, when used in ordinary homes, if there is a lighting device such as a fluorescent lamp in the center of the room, the antenna cannot be installed in the center of the room. Since the multipath wave enters the station antenna, there is a problem that the radio wave absorber 802 does not function sufficiently.
[0007]
In wireless communication at a very high frequency, such as a millimeter wave band of 10 GHz or more, particularly 30 GHz or more, a small directional antenna can be created relatively easily and the radio wave travels well, so a directional antenna is used for transmission. Thereby, the antenna gain can be increased and the output power can be reduced. Thereby, radio waves in unnecessary directions can be minimized, and interference and multipath can be reduced. In this case, line-of-sight communication is also possible using the reflection of radio waves on structures such as buildings (walls, ceilings, floors) and furniture. The result compensates for the attenuation and is more preferable.
[0008]
However, using a directional antenna for transmission is extremely difficult to set a radio wave propagation path with a receiver, because communication may not be established if the antenna direction is inappropriate in the initial state. As a result, an omnidirectional antenna having a wide radiation angle as in the prior art is to be used.
[0009]
An object of the present invention is to provide a wireless transmission system that does not require installation of a central antenna and a huge radio wave absorber and that can easily set a radio wave propagation path. Another object of the present invention is to provide a wireless transmission system that can easily set a radio wave propagation path while using a directional antenna for transmission.
[0010]
[Means for Solving the Problems]
The wireless transmission system of the present invention (claim 1) mainly includes a transmitter and a receiver,Means for automatically changing the directivity direction of the transmitting antenna, and means for determining the direction of the transmitting antennaWireless transmission systemAnd,
Perform wireless transmission between transmitter and receiverUsing radio waves of 10 GHz or moreFirst communication means;
SaidSecond communication means for transmitting a signal for determining the directivity direction of the transmitting antenna,
The second communication means,Communication means by any one of power line communication, optical communication, and sound wave communicationIt is characterized by the following.
[0011]
It is preferable that the information communication accompanying the setting of the antenna direction uses a different communication means which has an extremely small amount of information with respect to the original information content and can perform reliable communication. This is particularly effective when automatically selecting the directivity direction of the antenna.
[0012]
In this method, it is preferable to use a frequency having a high directivity of radio waves and a small directional antenna which is easy to produce. Therefore, it is preferable to use a frequency of 10 GHz or more. More preferably, when used at a frequency of 30 GHz to 90 GHz in the millimeter wave band, in which attenuation in the air and attenuation in reflection are rather large, interference with other stations and communication failure due to multipath can be prevented, and more stable communication can be achieved. A system can be built.
[0013]
Further, as information other than the directivity direction, selection of communication start / end information (power ON / OFF), communication channel (including frequency, TDMA, CDMA), communication content, and the like are performed by the second communication. It is possible to make the system easier to use. In particular, when the first wireless transmission is one-way communication, the second communication enables a transmitter and a receiver to control a power supply in cooperation with each other, which is particularly effective.
[0014]
In one embodiment,The wireless transmission system may be any one of power line communication, optical communication, sound wave communication, or wireless communication having a frequency different from the first communication means, or a combination thereof, as the second communication means. UsingYou.
[0015]
In the case of power line communication, power line communication is a method in which an electric signal is superimposed on a power line such as 100 V for home use for communication. Since the transmitting device and the receiving device are basically powered, mutual communication is possible almost certainly. Also, in an area where power line communication is not to be leaked, for example, when separating from each home to a neighbor or each floor in a building or the like, a signal can be easily cut off by attaching a band filter to the power line. It is suitable for a system such as a wireless LAN that uses a limited area.
[0016]
In the case of optical communication, the light is reflected on walls and ceilings in a room, and communication can be performed in almost all areas in a normal house. More preferably, it is infrared communication.
[0017]
In the case of sonic communication, communication is possible in almost all areas in a room of a normal house. More preferably, it is an ultrasonic wave. In the case of sound waves, there is an advantage that the coverage area is wider than that of optical communication.
[0018]
In the case of wireless communication with different frequencies, the radio wave propagation changes greatly due to the different frequencies, and the radio wave can wrap around to a non-line-of-sight region at the frequency of the first communication. More preferably, a frequency of 3 GHz or less, at which communication can be performed with almost no obstacle in a room or a building unit, is more preferable, and a frequency of 500 Hz or more and 2.5 GHz or less, at which radio waves do not fly too far, is preferable. Specifically, specific low-power communication, cordless telephone, PHS parent-child communication, and the like are preferable. It is preferable to use a communication between the parent and child units such as a cordless telephone because interference avoidance and confidentiality are already ensured and there is no interference with the same adjacent system.
[0019]
In the case of a plurality of these combinations, mutual coverage areas can be complemented. In particular, it is preferable to combine power line communication and other wireless communication. This is because, in addition to the reliability of the wired communication, it is possible to cover a portable device that is not wirelessly connected to the power line.
[0020]
In one embodiment,The wireless transmission system has means for automatically changing the directivity direction of the transmitting antenna, and means for determining at least one of the receiving strength of the receiver, interference, and multipath to determine the direction of the transmitting antenna. AlsoOne.
[0021]
The determination of the transmitting antenna is made by automatically and sequentially changing the directivity direction of the transmitting antenna and evaluating the reception situation at that time. The evaluation of the reception situation can be performed most simply by selecting a direction in which the reception intensity is high. However, it is more preferable to select a communication path free from interference and multipath.
[0022]
In this case, it is also effective to reduce the evaluation time by evaluating interference and multipath after evaluating the reception intensity.
[0023]
The final determination of the directivity direction of the transmitting antenna may be performed by the transmitting side by communicating the quality of the receiving side to the transmitting side in the second communication, or by transmitting the directivity angle from the transmitting side to the receiving side. It is also possible to do with. When the receiving side determines the directivity direction of the transmitting antenna, the transmitting side is finally instructed to set the antenna direction.
[0024]
It is also effective to reduce the evaluation time by roughly evaluating the angle while sequentially changing the angle and finely evaluating the good points. Also, by using a channel (frequency, CDMA, TDMA) for the transmission signal at this time, which is different from the content of the transmission, it is possible to prevent reception interference to others.
[0025]
In one embodiment,In a wireless transmission system, a transmitter has a plurality of transmission antennas including both a non-directional or low directivity first antenna and a high directivity second antenna, and uses the first antenna Transmit to multiple receivers simultaneouslyYou.
[0026]
Since the omni-directional or low-directivity antenna can cover many terminal stations at a time, a line-of-sight propagation path can be simultaneously provided to each terminal in the line-of-sight position. Therefore, the number of transmission antennas having high directivity can be reduced. In this case, it is more desirable to reduce the transmission output than an antenna with high directivity in order to reduce multipath and interference caused by radio waves from an antenna with low directivity.
[0027]
In one embodiment,A method of determining the directivity direction of an antenna in a wireless transmission system includes a method in which a receiver includes a first receiving antenna having no directivity or low directivity, and a second receiving antenna having higher directivity than the first receiving antenna. After selecting the directivity direction of the transmitting antenna using the first receiving antenna, selecting the directivity direction of the second receiving antennaYou.
[0028]
When the transmitting antenna is a directional antenna, if a directional antenna is used as the receiving antenna, it is necessary to evaluate the reception strength while changing the directions of both antennas, so that it becomes more difficult to set the propagation path.
[0029]
By using an omni-directional receiving antenna, the transmitting antenna is first set, and then the directional direction of the receiving antenna is changed, so that the directional directions of the transmitting and receiving antennas can be set one by one. It is possible to evaluate the directivity direction of the transmitting antenna.
[0030]
It is also possible to perform the first receiving antenna and the second receiving antenna using the same antenna whose directivity can be changed.
[0031]
In one embodiment,A method for determining the directivity direction of an antenna in a wireless transmission system is to store in advance a plurality of good directivity directions of a transmission antenna and to change the directivity direction of the transmission antenna to one of the plurality of directions when a communication failure occurs.You.
[0032]
In one embodiment,The method of determining the directivity direction of the antenna in the wireless transmission system is as follows. Change to transmitting antennaYou.
[0033]
In one embodiment,A method of determining the directivity direction of an antenna in a wireless transmission system is based on the fact that a transmitter has a plurality of transmission antennas and a communication path with one receiver is determined according to the degree of reception failure at each of a plurality of receivers. Eliminate reception problems at desired receivers by increasing or decreasing the number of transmit antennas assignedYou.
[0034]
The reception state of each terminal station is never the same, and for terminals where reception failure does not occur or hardly occurs, it is possible to reduce the allocation of transmission antennas of the base station, and a terminal having many reception failures Can be assigned a transmit antenna. This makes it possible to more reliably communicate with many terminals with a minimum number of transmission antennas.
[0035]
At this time, the reception failure uses a numerical value of a comprehensive evaluation made by evaluating the radio wave intensity, the presence or absence of interference, the degree of multipath, and the like.
[0036]
In actual operation, since the tolerance varies depending on the content and purpose of use of the information to be communicated, in addition to making a judgment based only on the above-mentioned evaluation, a weight between the above-mentioned judgments is set by a terminal, or A more stable communication system can be constructed by setting the weight between terminals.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram illustrating a method of setting the directivity direction of a transmission antenna when there is an obstacle in the transmission / reception system of the present invention.
[0038]
In FIG. 1, there are a base station 102 having a directional transmitting antenna 101 and a terminal station 104 having a non-directional receiving antenna 103 installed indoors or on the premises. A first wireless communication 105 is performed between the two.
[0039]
As the first wireless communication 105, simultaneous multi-channel video communication at 60 GHz was performed. As the video information, satellite broadcasting (about 300 channels including BS broadcasting and CS broadcasting) was used, and the entire band was set to 2 GHz. The communication was one-way communication transmitted from the base station and received by the terminal station.
[0040]
Hereinafter, in all figures, a directional antenna near 60 GHz is small and its direction is difficult to show, so that the directions of each antenna are replaced by simply showing the direction of the directional beam. In the case of an omnidirectional or low directivity antenna, it is tentatively displayed in the form of a rod antenna.
[0041]
Actually, it is composed of a horn antenna, a patch antenna (planar antenna) and the like. The directivity of the antenna was changed by changing the angle of the antenna itself with a step motor or the like. The directional antenna preferably has a radiation angle as narrow as possible and a high antenna gain.
[0042]
The base station 102 needs to direct the directivity direction of the transmission antenna 101 to the optimal direction for connection of the first wireless communication line. FIG. 1 shows a situation where the line-of-sight direction 106, which is one of the optimal directions, is blocked by an obstacle 107 that does not transmit radio waves.
[0043]
When performing communication with the base station 102 at the terminal station 104, the operator uses the remote control device 110 to transmit a setting signal of the antenna directivity to the base station 102 by the ultrasonic wave 109, and the base station 102 The antenna direction 112 is set according to the above, and test transmission is performed in the frequency band of the first communication 105. The terminal station 104 measures and displays the wireless reception intensity of the communication 105 (or displays the received image by using the test transmission as a video signal itself), and the operator evaluates the intensity (or image quality).
[0044]
The operator repeats the above method, sequentially changes 112 the directivity direction of the transmitting antenna 101, and selects the best antenna directivity direction from among them, in the case of FIG. Is selected, the antenna directivity direction is designated to the base station 102, and the first communication is started. By the above method, even if there is an obstacle, the directivity direction of the transmitting antenna can be easily selected, and a communication path using reflection of ceiling, wall, furniture, etc. can be easily secured, and broadband wireless communication is possible. Met.
[0045]
The remote controller 110 was able to save energy at the base station by controlling the power of the base station to be turned on and off in addition to the direction of the antenna.
[0046]
An audible sound wave can be used in place of the ultrasonic wave for the second communication, but the ultrasonic wave is preferable because the communication time is quiet. Further, light can be used instead of sound waves. In this case, infrared light is not visible during the second communication, which is preferable. Furthermore, it is also possible to use radio waves of a different frequency from the first communication for the second communication. By using 110 and 111 in the figure as communication devices having a cordless telephone handset function, reliable communication was possible. In this case, the interference of the second communication with the neighbor was prevented by the cordless telephone's own interference prevention and confidentiality functions, and more stable communication was achieved.
(Embodiment 2)
Next, an example in which the directivity direction of the transmission antenna is automatically set will be described.
[0047]
FIG. 2 shows a method of automatically setting the directivity direction of the transmitting antenna 201 of the base station 202, assuming the base station 202 and the terminal station 204 in the same situation as in FIG.
[0048]
Therefore, 201 to 209, 211, and 212 in the figure correspond to 101 to 109, 111, and 112 in FIG. The same communication information and communication frequency as in Embodiment 1 were used.
[0049]
FIG. 3 shows a procedure of the first communication by wireless and the second communication by sound waves.
[0050]
The terminal station 204 transmits the setting signal S1 of the antenna directivity by the ultrasonic wave 209 from the ultrasonic remote control transmitting device 210, and the base station 202 receives the signal by the ultrasonic remote control receiving device 211 and sets the direction of the antenna 201 accordingly. , The test signal S2 is transmitted in the frequency band of the first communication 205. The terminal station 204 measures the wireless reception strength of the communication 205.
[0051]
The terminal station 204 repeats the above method a plurality of times (S3 in FIG. 3), sequentially changes the directivity direction of the transmitting antenna 201, stores the corresponding reception intensity, and selects the strongest reception intensity from among them. The terminal station 204 transmits a signal S4 designating the directivity direction and the start of information to the base station 202.
[0052]
The base station 202 sets the antenna 201 to the designated directivity direction and starts the first wireless communication 205 (S5 in FIG. 3), so that communication can be performed with the transmission antenna having the optimal directivity direction.
[0053]
The order of changing the directivity direction of the transmission antenna is such that the numbers are sequentially assigned to the directions that can be simply set, and the sweep is performed in the order of the numbers according to the instruction of the terminal station. In this case, after measuring the reception intensities of all the numbers, it was possible to finally set the antenna direction by specifying a preferable number from the terminal station. If the signal from the terminal station is made up of two-axis angle data, the terminal station can freely specify the angle. Therefore, the omnidirectional search is performed coarsely, and the preferable direction is more finely investigated. The direction of directivity can be set, and time can be reduced.
[0054]
It is also possible to instruct the base station to turn on / off the power supply of the information source for information communication (in this example, the reception antenna for satellite broadcasting and the power supply for the converter) together with the S1 signal from the terminal station. , Transmitting selection information such as selection of a plurality of information sources, for example, CS broadcast and BS broadcast, or selection of vertical polarization channel of CS broadcast, vertical polarization channel, etc., and selection of transmission information corresponding to the base station. By doing so, it is possible to make the system easier to use.
[0055]
Further, when the first communication is completed, a signal S6 for instructing the base station to end the communication is transmitted, and the base station turns off the power source of the information source unless another terminal station uses the information. It is also possible to build an energy-saving system by turning it off.
[0056]
In the present embodiment, the second communication is one-way communication from the terminal 204 to the base station 202. However, the second communication is a two-way communication, and a signal indicating completion of changing the directivity direction of the antenna, By transmitting information such as the range to the terminal station, it is possible to more stably determine the antenna directivity direction.
(Embodiment 3)
Next, an example in which there are two terminal devices will be described.
[0057]
FIG. 4A shows an example in which there are two terminal devices (401, 402) and one base station 403 but a plurality of antennas.
[0058]
The same communication information, communication frequency, and second communication method as in Embodiment 1 were used. The terminal devices 401 and 402 select a plurality of candidates of preferred directions of the directional transmission antennas 404a to 404e of the base station 403 by the same method (S1, S2, and S3 in FIG. 3) as in the first embodiment. The second communication is not shown.
[0059]
When the reception state is relatively poor (this is the case of the terminal device 401 in this figure), the plurality of transmission antennas 404a to 404c are set as candidates for different directivity directions, and one of them is used for communication (S4 in FIG. Perform S5).
[0060]
Then, when the communication path is interrupted, an instruction to switch to a different transmission antenna (S7 in FIG. 3) is issued from the terminal 401 to the base station 403, and the base station 403 sets the transmission antenna set as a candidate for a different directivity direction. The transmission was switched (S8 in FIG. 3) to prevent the communication from being interrupted.
[0061]
If the reception condition is relatively good (for example, the terminal device 402 corresponds to the position almost directly below the base station and there is no obstruction in this figure), a wireless communication path is secured by one of the transmission antennas 404d, When the worst route is interrupted, communication interruption can be minimized by changing to another candidate 404e that stores the directivity of the antenna and responding.
[0062]
In that case, it is effective to increase the number of allocated antennas in preparation for the interruption of the next radio wave propagation path. Specifically, the assignment of the antenna 404c to the terminal station 401 is removed from the assignment to the terminal station 402, and the same direction as 404e (original 404d direction when 404d is oriented to 404e) is set next time. When the radio wave propagation path is interrupted, communication can be interrupted by switching the antenna immediately.
[0063]
In this case, how many antennas to secure for each terminal can be determined by transmitting the reception status from the terminal station to the base station, and the base station can make a judgment. A method of increasing / decreasing is also possible, and depending on the communication method, it is also possible to adjust between the terminals 401 and 402 to increase / decrease.
[0064]
Also, if the base station 403 has one omnidirectional antenna 405, terminal stations in all directions can be used, so that the number of antennas required for the base station 403 can be reduced. In the case of FIG. 4, the number of directional antennas 404a and 404d used for direct wave communication of each terminal can be reduced, and more stable communication can be performed by distributing the new antenna to another path. In this case, since the omnidirectional antenna 405 emits radio waves in all directions, the output needs to be smaller than that of the directional antennas 404a to 404d so as not to increase interference and multipath.
[0065]
FIG. 4B shows a conceptual relationship between the antenna directivity angle of the transmission antenna and the reception intensity of the receiver. Here, the reception intensity becomes maximum in the direction of P1, and takes different maximum values in P3. In this case, the P1 direction is the first candidate of the selected direction. As the second candidate, for example, the reception intensity in the direction of P2 is larger than the reception intensity in the direction of P3, but it is more preferable to set it to P3. This is because P1 and P2 have propagated on almost the same route, and if the route is interrupted by movement of a person or the like, there is a high possibility that the route will be interrupted at the same time. Therefore, it is preferable to sequentially select candidates for different directivity directions from different local maxima that are as far apart from each other as possible. Further, although the vertical axis in FIG. 4B is described as the reception intensity of the receiver, a candidate for the directivity direction of the transmission antenna is selected by the above method as an evaluation taking into account interference and multipath failure. Thus, more stable communication can be performed.
(Embodiment 4)
An example in which the second communication for determining the transmission antenna directivity is performed by a power line in the transmission / reception system of the present invention will be described with reference to FIG.
[0066]
In FIG. 5A, there are a base station 502 having a directional transmitting antenna 501 and a terminal station 504 having a directional receiving antenna 513 installed indoors or on the premises. A first wireless communication is performed between the stations 504.
[0067]
The same communication information and communication frequency as in Embodiment 1 were used.
[0068]
In this figure, the communication for determining the directivity of the transmitting antenna is performed by communication 509 from the power line communication transmitting device 510 of the terminal station to the power line communication receiving device 511 of the base station via the power line (home power supply 100 V) 515. ing.
[0069]
In addition, a band filter 516 is provided so that a signal of the second communication using the power line does not leak to the outside (outdoor or off-premises) through the power line.
[0070]
Since the receiving antenna 513 has directivity, the scan direction 514 of the receiving antenna 513 is changed every time the directivity direction of the transmitting antenna 501 is changed 512, and the directivity angle and the receiving intensity at the highest receiving intensity are stored. Then, after confirming all directions of the transmitting antenna 501, the transmitting antenna directivity direction having the highest receiving strength is transmitted to the base station 502, and the receiving antenna 513 is set to the corresponding directivity direction.
[0071]
Here, since the direct wave 506 is shielded by the obstacle 507 as in the first and second embodiments, the reflected wave 508 shows an optimal state.
[0072]
An omnidirectional or weakly directional antenna 503 is separately used for the receiver, and the strength of the transmitting antenna 501 is evaluated, so that the omnidirectional antenna 503 is used instead of scanning the entire receiving antenna 513 every time the direction is changed. By selecting the optimum candidate for the transmitting antenna direction and then scanning the direction of the receiving antenna 513, the setting time for the antenna direction can be reduced.
[0073]
When the receiving state of the omnidirectional antenna 503 is good, the receiving antenna can be used as one of the wireless communication paths similarly to the directional antenna 513 to increase the number of paths, and a more stable communication system is possible. is there.
[0074]
In this embodiment, the first communication is described as one-way communication from the base station to the terminal station. However, the first communication can also be applied to phase communication, and in this case, the first communication can also serve as a directional receiving antenna. Alternatively, transmission and reception can be performed by different routes.
[0075]
FIG. 5B shows another embodiment of the terminal station. The terminal device 504 is a general electronic device (such as a television), and 517 is its power line and antenna line. Here, the power line communication transmitting apparatus 510 monitors the power supply of the terminal apparatus 504, automatically turns on the power of the antenna unit 518 when the power supply of the terminal apparatus 504 is turned on, and starts setting the antenna directivity direction of the base station. Like that. With a terminal station having this configuration, a general electronic device can be connected as it is, so that a dedicated television or the like is not required, and the system can be configured at a low price.
[0076]
FIG. 6A shows another embodiment of the terminal station. The terminal device 612 is a portable device, and is not connected to a power line. The situation is the same as FIG. 5A except that the base station has the same number of transmitting antennas 601 as the number of terminal devices (in this case, two). The terminal device 621 transmits an antenna directivity direction setting signal with the infrared remote control transmitting device 623 to determine the direction of the transmitting antenna 601 of the base station 602, and the repeater 620 receives the infrared remote control signal and converts the signal into the power line communication signal 609. Conversion and transmission to the power line communication receiver. With this configuration, equipment not connected to the power line could be used.
[0077]
The infrared communication and power line communication repeater 620 can be installed near the ceiling of a room or on a wall, or as shown in FIG. 6B, an infrared communication unit 632, a power line communication unit 631, and an outlet plug 633 are integrated. In this case, it is possible to reduce the construction cost of the equipment by carrying the portable device 604 to each room in accordance with the movement of the portable device 604 and plugging it into the household 100V outlet 634 so that the portable device 604 can be used. In FIGS. 6A and 6B, infrared rays are used, but wireless communication having a different frequency from that of sound waves, light, and the first communication is possible. In the form of FIG. And a repeater when using power line communication.
(Embodiment 5)
Next, switching of the transmitting / receiving antenna of the present invention will be described with reference to FIG. In FIG. 7, there are two terminal devices (701, 702) and one base station 703. The same communication information and communication frequency as in Embodiment 1 were used. The second communication is not shown.
[0078]
The terminal devices 701 and 702 select a plurality of candidates for the preferred directions of the transmitting antennas 704a to 704d of the base station 703 and the preferred directions of the receiving antennas 707a to 707d in the same manner as in the fourth embodiment. The use of the omnidirectional antenna 706 of the terminal station can shorten the transmission / reception antenna selection time as in the third embodiment.
[0079]
The terminal device 701 secures a wireless communication path with a plurality of antennas 705a to 705c, and performs reception using the antenna 705a having a good reception state. If the reception state deteriorates, the terminal device 701 switches to another better antenna 705b, c. Switch.
[0080]
In this case, the transmission is always performed from all the antennas 704a to 704c, and only the switching of the reception antenna 705 may be performed. However, only the transmission antenna 704 that is normally used is used, and the reception antenna 704a is used when the path is switched. It is also possible to switch 705 and the transmitting antenna 704 from a to b at the same time. Since the latter does not emit unnecessary radio waves from the base station, interference and multipath failure can be reduced. Alternatively, by transmitting the transmission antennas 704a and 704b redundantly only during a certain period of switching, it is effective to prevent disconnection of communication due to a time lag of switching between transmission and reception.
[0081]
In this way, when the terminal station has a plurality of antennas and the wireless communication path is interrupted, it is possible to immediately use another antenna direction. In that case, how many antennas are secured for each terminal can be performed in the same manner as in Embodiment 3. In FIG. 7, the terminal 702 is almost directly under the base station and is not blocked, and one antenna is used. This shows the state of being assigned. Only the antennas of the terminal stations 701 and 702 used in the description are shown, and a greater number of antennas may be provided.
[0082]
In addition, if the base station has one omni-directional antenna 706, the terminal stations in all directions can be used, so that the number of antennas required for the base station can be reduced. Therefore, it is necessary to sufficiently reduce the transmission output.
[0083]
When the reception state of the omnidirectional antenna 707 is good, the number of paths can be increased by using the omnidirectional antenna 707 as a radio communication path in the same manner as the directional antenna, and a more stable communication system is possible.
[0084]
In the first to fifth embodiments, the base station performs transmission and the terminal station performs reception. However, if the configuration is reversed, the base station can perform reception and the terminal station can perform transmission. Alternatively, the base station and the terminal station have both configurations, so that transmission and reception in the phase direction can be performed. In that case, it goes without saying that the antenna can be shared if possible for transmission and reception.
[0085]
Although the contents of wireless communication are described in the case of satellite broadcasting, there is no particular designation, and television (terrestrial broadcasting, satellite broadcasting (BS broadcasting, CS broadcasting), radio, home video, surveillance video camera signal, videophone, etc. In particular, in a broadband communication in which a plurality of pieces of information are transmitted and received collectively, it is difficult to secure a communication path by a diversity system or the like in each channel. The configuration is particularly effective.
[0086]
Although the example of the radio frequency is 60 GHz, it is preferable to use a frequency of 10 GHz or more because it is preferable to use a frequency in which the directivity of radio waves is high and the directional antenna is small and easy to make. More preferably, when used at a frequency of 30 GHz to 90 GHz in the millimeter wave band, in which attenuation in the air and attenuation in reflection are rather large, interference with other stations and communication failure due to multipath can be prevented, and more stable communication can be achieved. A system can be built.
[0087]
Although not particularly described in the embodiments, the terminal station is an electronic device corresponding to the above communication contents. With the above configuration, a communication path can be reliably ensured even in a small portable TV or the like. For terminals that hardly move, such as a large TV, the above-mentioned antenna setting is performed only when the antenna is set up or when the arrangement of furniture in the room is changed. Usually, the stored transmission antenna direction is used to perform communication. It is also possible to shorten the time until the start.
[0088]
When a communication path is secured using a plurality of antennas, the first communication is started when one path is found, and the procedure for securing another path is continued in parallel with the first communication. The time to start can be shortened.
[0089]
The obstacles shown in FIGS. 1, 2, 5, and 6 are metallic ones that reflect radio waves, and wooden ones become obstacles by absorbing radio waves above 30 GHz. Room partitions, furniture, and lockers and bookcases in offices are equivalent.
[0090]
In the first, second, and third embodiments, the ultrasonic wave is set, in the fourth and fifth embodiments, the power line carrier communication is set, and in a part of the fourth embodiment (FIG. 6A), the combination of the power line communication and the infrared communication is set. The communication method used for the communication is not limited to ultrasonic waves, but may be sound waves in the audible range, or may be light in the visible range in addition to infrared rays. In addition, wireless communication different from the frequency of the first communication, in particular, a wireless communication having a low frequency and a wider radio wave propagation area than that of the first frequency can be used. In this configuration, since these communications are used for line setting, the transmission / reception capacity may be extremely small as compared with the first communication, so that a very simple circuit configuration is possible.
[0091]
Rather, since certainty between transmission and reception is more important, it is preferable to increase the certainty by combining a plurality. In particular, it is more preferable to combine wireless methods such as the above-described radio waves, light, and sound waves in order to secure reliable communication using wired communication such as power line communication and cover a portable device not connected to the power line. . In the case of using radio waves, it is practical to use a frequency band for communication between parent and child units, such as a cordless telephone and a PHS telephone, so as to cover a room, a house, a premises, and the like.
[0092]
In the embodiment of the present invention, an example has been described in which the receiver issues an instruction and the transmitter performs antenna setting. However, in this method, it is possible to include an instruction to start a communication procedure to the base station. One-way communication from the receiver is sufficient, and in the case where the original wireless communication is one-way communication by transmission from the base station, there is an advantage that after the communication path is set, the communication becomes bidirectional with a minimum configuration.
[0093]
If it is only the evaluation of the communication line, the receiver transmits the reception intensity, the transmitter changes the directivity direction of the antenna, and it is also possible to evaluate with the reception intensity signal from the receiver. The time lag is also preferable because the transmitter can be taken into consideration, but usually there is a drawback that the terminal station is often at hand, so that communication is performed in two directions due to an instruction to the base station.
[0094]
The directivity of the transmitting antenna can be simply changed by changing the antenna direction of the directional antenna, but it is also possible to change the direction by moving a phased array antenna or a reflector installed in front of the antenna. . In particular, when the same ultra-wide band signal is output from a plurality of antennas, there is an advantage that a plurality of paths can be easily secured by branching a radio wave by a reflector and changing the path, rather than adding an additional antenna.
[0095]
【The invention's effect】
Of the present inventionAccording to the configuration, it is possible to secure the communication path by selecting the directivity direction of the antenna without depending on the radio wave propagation characteristic of the first wireless transmission, and it is possible to configure the circuit with a simple circuit at a low cost.
[0096]
In one embodiment,According to the configuration, a stable communication system can be operated by selecting a preferable communication path.
[0097]
In one embodiment,With the configuration, the number of transmission antennas having high directivity can be reduced.
[0098]
In one embodiment,According to the configuration, it is possible to set the directivity direction of the transmitting and receiving antennas one by one by setting the transmitting antenna first by using the non-directional receiving antenna and then changing the directivity direction of the receiving antenna. Therefore, it is possible to evaluate the directivity direction of the transmitting antenna in a short time.
[0099]
In one embodiment,According to the configuration, SendBy evaluating the directivity direction of the transmitting antenna and storing the good directivity directions of a plurality of different directions in advance, the directivity direction of the transmitting antenna can be changed in a short time.
[0100]
In one embodiment,According to the configuration, by setting a plurality of transmission antennas in good directivity directions in different directions in advance, it is possible to change the directivity direction of the transmission antenna in a short time.
[0101]
In one embodiment,According to the configuration, it is possible to more reliably communicate with many terminals with the minimum number of transmission antennas.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a method of setting a directivity direction of a transmission antenna when an obstacle is present in a transmission / reception system of the present invention.
FIG. 2 is a diagram illustrating a method for automatically setting the directivity direction of a transmission antenna in the transmission / reception system of the present invention.
FIG. 3 is a diagram showing a procedure of a first communication by radio and a second communication by sound waves in the transmission / reception system of the present invention.
FIG. 4 is a diagram illustrating a case where there are a plurality of terminal devices and a base station has a plurality of antennas in the transmission / reception system of the present invention.
FIG. 5 is a diagram illustrating an example in which communication for determining transmission antenna directivity is performed by a power line in the transmission / reception system of the present invention.
FIG. 6 is a diagram showing an example in which communication for determining transmission antenna directivity is performed using a power line and infrared light in the transmission / reception system of the present invention.
FIG. 7 is a diagram showing switching of a transmitting / receiving antenna in the transmitting / receiving system of the present invention.
FIG. 8 is a diagram showing a conventional transmission / reception system.
[Explanation of symbols]
101: Directional transmitting antenna
102 ... Base station
103 omnidirectional receiving antenna
104 ... Terminal station
105: First communication by wireless
106 ... Line of sight
107: Obstacle that does not transmit radio waves
108: Connection path of wireless communication line using reflection from ceiling and wall
109: Setting signal of antenna directivity direction by ultrasonic wave
110 ... Ultrasonic remote control transmitter
111 ... Ultrasonic remote control receiver
112... Change in directionality of transmitting antenna
201: Directional transmitting antenna
202 ... Base station
203 ... omnidirectional receiving antenna
204 ... Terminal station
205: First communication by wireless
206: Optimal direction (line of sight)
207: Obstacle that does not transmit radio waves
208: Connection path of wireless communication line using reflection from ceiling and wall
209: Transmitting setting signal of antenna directivity direction by ultrasonic wave
210 ... Ultrasonic remote control transmitter
211 ... Ultrasonic remote control receiver
212: Change in directionality of transmission antenna
401: Terminal device with relatively poor reception
402: Terminal device with relatively good reception status
403 ... Base station
404a-d ... directional transmission antenna
405 omnidirectional transmitting antenna
406 omnidirectional receiving antenna
410: Directivity direction (angle) of transmitting antenna
411 ... Reception strength
412: Directivity direction of transmission antenna with maximum reception intensity
413: Directivity direction of the transmitting antenna having the maximum reception intensity
414: Directivity direction of transmitting antenna with high receiving strength
501 ... directional transmission antenna
502 ... Base station
503 omnidirectional receiving antenna
504 ... terminal station
505: First communication by wireless
506: Optimal direction (line of sight)
507: Obstacle that does not transmit radio waves
508: Connection path of wireless communication line using reflection from ceiling and wall
509: Setting signal of antenna directivity direction by power line communication
510 ... Power line communication transmitting device
511: Power line communication receiver
512: Change in directionality of transmission antenna
513: Directional receiving antenna
514... Change in directionality of receiving antenna
515 ... Power line
516… Band filter
517: power line (100 V), antenna cable
601 directional transmission antenna
602: base station
604 ... terminal station
607: Obstacle that does not transmit radio waves
609: Setting signal of antenna directivity direction by power line communication
610: Power line communication transmitting device
611: Power line communication receiver
615: Power line
616 ... Band filter
618 ... High frequency unit
620: Relay device for infrared remote control and power line communication
621: portable terminal
622: Infrared communication
623 ... Infrared remote control transmitter
631 infrared communication, power line communication repeater
632: infrared receiving unit
633: outlet plug
634… Home 100V outlet
701: Terminal device with relatively poor reception
702: Terminal device with relatively good reception
703 ... Base station
704a-d ... directional transmission antenna
705 omnidirectional transmitting antenna
706 omnidirectional receiving antenna
707a-c: Directional receiving antenna
801 ... Base station antenna
802: radio wave absorber
803 ... Terminal station
804 ... directional antenna
805: direct wave
806: reflected wave
807: Multipath wave
808: Radiation characteristics of narrow band

Claims (3)

A wireless transmission system mainly including a transmitter and a receiver, and a means for automatically changing a directivity direction of a transmission antenna, and a means for determining a direction of the transmission antenna,
First communication means using radio waves of 10 GHz or more for wireless transmission between a transceiver and
And second communication means for transmitting a signal for determining the directivity direction of the transmission antenna,
The wireless transmission system according to claim 2, wherein the second communication unit is a communication unit based on any one of power line communication, optical communication, and sound wave communication. A wireless transmission system mainly including a transmitter and a receiver, and a means for automatically changing a directivity direction of a transmission antenna, and a means for determining a direction of the transmission antenna,
First communication means using radio waves of 10 GHz or more for wireless transmission between a transceiver and
And second communication means for transmitting a signal for determining the directivity direction of the transmission antenna,
A wireless transmission system, wherein the second communication unit is a communication unit combining a plurality of power line communication, optical communication, sound wave communication, and communication using radio waves of 3 GHz or less . A wireless transmission system mainly including a transmitter and a receiver, and a means for automatically changing a directivity direction of a transmission antenna, and a means for determining a direction of the transmission antenna,
First communication means using radio waves of 10 GHz or more for wireless transmission between a transceiver and
And second communication means for transmitting a signal for determining the directivity direction of the transmission antenna,
A wireless transmission system, wherein the second communication means is a communication means in which any one of optical communication, sound wave communication, or communication using radio waves of 3 GHz or less is combined with power line communication. .

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