JP2000049672A - Radio transmission/reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To receive wide band signals including multi channels without the need of diversity circuits for the number of the channels by selecting a route where the wide band signals including multi channels are not superimposed by multi-path. SOLUTION: In order to select an optimum reception antenna, the plural reference signals of a frequency different from that of super wide band signals 206 and the same signal strength are simultaneously transmitted from a transmission antenna 201. When the ones of the low strength are included in the signal strength of a part of the reference signals 207 received by a reception antenna 202, the substantial decline of the strength occurs in a part of signals for reception signals 208. Thus, in the case of receiving them by the reception antenna 202, the ones with more than fixed difference in the plural reference signals 207 are excluded as the signals including the multi-path. Also, in the case that the strength of the received reference signals are the same (reference signals 209 and 211), the reception antenna is selected in the descending order of the strength of the reference signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for wirelessly transmitting and receiving wideband signals such as BS and CS, and more particularly to a method for wirelessly transmitting and receiving wideband signals indoors and premises using millimeter waves.

[0002]

2. Description of the Related Art Normally, in mobile radio communication, diversity reception has been devised in order to perform stable reception while avoiding the effects of multipath fading. As disclosed in Japanese Patent Application Laid-Open No. 29995, a method using reception intensity comparison circuits and antenna switching circuits for the number of channels has been devised.

[0003] As an apparatus for collectively receiving a large number of radio waves including multi-channel signals disclosed in Japanese Patent Application Laid-Open No. 5-29995, the present application will describe a case where the apparatus is applied to broadcast communication such as satellite broadcasting. FIG. 11 shows a wireless transmission / reception device of the prior art.

A multi-channel transmission signal 1004 in which each channel is arranged on the frequency axis is transmitted by a transmission antenna 100.
Sent from 1. Intensity is significantly reduced in some channels due to the effect of fading due to multipath in spatial transmission. Therefore, when reception is performed by a plurality of antennas 1002 and 1003, reception is performed by selecting an antenna having high intensity in each channel (diversity). Receiving). For example,
In channel 1005 of the received signal, channel 1005
5, the antenna 1003 having a high strength is independently selected for the channel 1006 of the received signal. As a result, stable reception is possible on a plurality of channels.

[0005]

The information of each channel of the transmission signal 1004 is a TV video signal, and in order to display a multi-screen video on a cathode ray tube, as many selection circuits as the number of antennas 1002 and 1003 are required. It will be. If only the counter program is displayed, two channels are required, and 16 channels are required to display a plurality of channels on a 16-split screen. Also, considering a case where transmission methods are different between channels such that a certain channel is a digital signal and a certain channel is an analog signal,
An antenna switching circuit corresponding to each transmission method is required, resulting in a very complicated system.

In the above-mentioned method, it is inevitable that diversity circuits are required for the number of channels.
In Japanese Patent Application No. 29995, the circuit is devised in order to reduce the number of circuits. However, a reception intensity comparison circuit and an antenna switching circuit are required for the number of channels. Furthermore, in the case of this system, the diversity circuit must follow the diversity circuit when switching the reception channel and switch the evaluation frequency, and the entire receiving system needs to be a system dedicated to the diversity circuit.

An object of the present invention is to provide a radio transmitting / receiving method capable of receiving a wideband signal including multiple channels without requiring a diversity circuit of the number of channels.

[0008]

According to a first aspect of the present invention, there is provided a wireless transmitting / receiving method having a plurality of paths for transmitting / receiving a wideband signal including multiple channels from a transmitter to a receiver via a receiving antenna. Wherein a path on which the wideband signal is not superimposed is selected by multipath.

[0009] A wireless transmitting / receiving method according to a second aspect of the present invention is characterized in that the broadband signal is a millimeter wave band signal.

[0010] According to a third aspect of the present invention, there is provided the radio transmission / reception method, wherein reference signals having the same signal strength on a plurality of frequencies are inserted into the wideband signal and transmitted, and a signal strength difference between the plurality of received reference signals is received. By choosing routes with smaller
A path on which a wideband signal is not superimposed is selected by the multipath.

According to a fourth aspect of the present invention, there is provided the radio transmission / reception method, wherein a reference signal having a constant signal strength is transmitted to the wide band signal by sweeping the frequency, and a difference in signal strength during the sweep of the received reference signal is small. By selecting
A path on which a wideband signal is not superimposed is selected by the multipath.

[0012] According to a fifth aspect of the present invention, there is provided a radio transmission / reception method, wherein spectrum information in a signal band is inserted and transmitted on a frequency different from the wideband signal, and the frequency distribution of the received wideband signal and the signal band are transmitted. And selecting a path in which the difference between the frequency distribution of the wideband signal and the spectral information in the signal band is small by comparing the spectrum information within the wideband signal and a path on which the wideband signal is not superimposed by the multipath. It is characterized by the following.

According to a sixth aspect of the present invention, there is provided a radio transmission / reception method according to any one of the third to fifth aspects, wherein the strength of the received reference signal is selected from the paths on which the wideband signal is not superimposed by the multipath. Is selected.

According to a seventh aspect of the present invention, there is provided a radio transmission / reception method according to any one of the third to fifth aspects, wherein the reference signal is superimposed on the multipath by the multipath at the start of transmission or at the start of reception. Select multiple routes that are not
The method is characterized in that a path having a high strength of the received reference signal is selected by appropriately inserting the reference signal at a frequency different from the wideband signal.

[0015] In a wireless transmission / reception method according to an eighth aspect of the present invention, the antenna is movable, and the direction of the antenna is selected by the method according to any one of the third to seventh aspects. And

According to a ninth aspect of the present invention, in the wireless transmission / reception method, the antenna is a phase array antenna.

[0017] A wireless transmission / reception method according to a tenth aspect of the present invention is characterized in that the arrangement of the antenna is angle diversity.

[0018] A wireless transmission / reception method according to claim 11 of the present invention is characterized in that the arrangement of the antenna is position diversity.

[0019] A wireless transmission / reception method according to a twelfth aspect of the present invention is characterized in that the arrangement of the antenna is frequency diversity.

[0020] A wireless transmitting / receiving method according to claim 13 of the present invention is characterized in that the transmitter has a directional antenna.

According to a fourteenth aspect of the present invention, there is provided a wireless transmitting / receiving method, wherein the transmitter includes a plurality of or repeaters.

[0022]

(Embodiment 1) FIG. 1 shows an embodiment of a radio transmitting / receiving method according to the present invention. Here, BS, C
An example of a system for simultaneously transmitting and receiving all channels of S broadcast will be described.

Since there are a large number of channels, all channels are converted into one ultra wide band signal (60 GHz to 61.5 GHz).
This is shown as 105. The transmitter receives BS and CS broadcasts and converts them to IF frequencies of about 1 to 1.5 GHz using block converters used in general apartment buildings, and converts them to millimeter waves (60 to 61.5 GHz). And the ultra wideband signal 105 is transmitted from the transmission antenna 101. The ultra wideband signal 105 is received by a plurality of receiving antennas 102, 103, 104.

At this time, in the present embodiment, it is assumed that the receiving situation is as follows. Due to the multipath in the receiving antenna 102, the received signal 106 is a received signal 106 in which the strength of some of the signals is significantly reduced. Receiving antenna 10
In No. 3, only the direct wave from the transmitting antenna is received, and the received signal 107 has no difference in intensity between the channels.
Since the receiving antenna 103 receives the reflected wave,
The reception signal 108 has a channel whose reception intensity is low but has no extremely low reception intensity because there is no multipath.
In this case, good reception becomes possible by selecting the receiving antenna 103. Further, when the receiving sensitivity of the receiving antenna 103 is reduced (eg, shadowing) due to a person blocking the transmitting / receiving antenna, switching to the receiving antenna 104 enables stable reception. A specific method for selecting the receiving antennas 103 and 104 will be described below.

FIG. 2A shows a method for selecting an optimum receiving antenna in the first embodiment. Ultra wideband signal 2
A plurality of reference signals 205 having the same signal strength and different frequencies from those of the reference signal 205 are simultaneously transmitted from the transmitting antenna 201. If the signal strengths of the plurality of reference signals at the time of reception are different, it is determined that the path has a multipath. In this embodiment,
When the signal strength of a part of the reference signal 207 received by the receiving antenna 202 includes a small signal strength, it can be understood that the received signal 208 has a remarkable decrease in the strength of the part of the signal. Therefore, when the signal is received by the receiving antenna 202, even if the signal having the lowest signal strength among the plurality of reference signals 207 does not fall below the receiving sensitivity, the receiving sensitivity greatly decreases in all the frequencies of the actual received video signal. Since the received signal 208 includes a channel that is present, a signal having a certain difference or more is excluded as a signal including a multipath.

In the case of antennas having the same signal strength of a plurality of received reference signals, the receiving antennas are selected in descending order of the strength of the reference signals. In the present embodiment, in the case of the receiving antennas 203 and 204, the received reference signal 20
9 and 211 are the same, and the received signals 210 and 212 are not affected by multipath. In this case,
Receiving antenna 20 having high signal strength of received reference signal
Select 3. Note that the path to the receiving antenna 203 is an example in which a single path is a path directly transmitted and received from the transmitting antenna to the receiving antenna.
The route to 04 is an example of a route reflected during transmission and reception.

Next, FIG. 2B shows a circuit example of a receiving apparatus used in the radio transmission / reception method described with reference to FIG. 2A.
The signal received by the receiving antenna 231 is transmitted to the RF amplifier 23
, And enters the mixer 234, where the local oscillator 2
The signal is mixed with the frequency from the signal 33 and becomes a signal in the IF frequency band. The reference signal is extracted by the filter 236 and enters the reference signal comparison circuit 237. In FIG. 2B, 3
In this example, three circuits having the same configuration are arranged in parallel, and each of them is input to the reference signal comparison circuit. The reference signal comparison circuit 237 selects the most suitable antenna based on the reference signal, turns on the switch 238,
Turn off. The output from the mixer 234 is the filter 2
35, a wideband signal is output from the filter 235, and the IF signal output terminal 2
Output to 39. Normal B signal output terminal
If an S / CS broadcast IF signal receiving device is connected, any channel can be selected only by selecting the channel of the receiving device. It is also possible to connect a plurality of receivers and to independently select different channels.

In this embodiment, by providing a plurality of receiving antennas, an optimum antenna is selected from the plurality of receiving antennas. However, one receiving antenna is made movable and an optimum position of the receiving antenna is determined. Alternatively, the method of the present invention may be used.

(Embodiment 2) FIG. 3 shows an example of an antenna selection method different from that of Embodiment 1. A reference signal 305 that has been frequency-swept on a frequency different from that of the ultra-wideband signal 306 is transmitted from the transmitting antenna 301. If the signal strength of the received reference signal changes during the sweep, the path is determined to have a multipath, and the receiving antenna used for the path is excluded. In this embodiment, the signal strength changes during the sweep of the reference signal received by the receiving antenna 302, and the receiving antenna 302 is excluded because there is a change exceeding a certain value. Here, the change exceeding a certain value is a value appropriately determined by the user according to the use environment and the like.

If the received reference signal does not change during the sweep, a path having a large reference signal strength is selected. In the case of the present embodiment, the signal strength of the reference signal 309 received by the reception antenna 303 and the signal strength of the reference signal 311 received by the reception antenna 304 are compared, and the path of the reception antenna 303 having a large signal strength is selected. .

In the path where the strength of the reference signal has not changed, the antennas are selected in descending order of the strength of the reference signal. Therefore, in the present embodiment, the path of the receiving antenna 303 having a large received reference signal strength is selected.

In the case where the frequency sweep is performed as in the present embodiment and a path is selected based on the change, the sampling frequency can be made larger than that in the first embodiment, so that it is very effective to find a multipath. is there.

FIG. 4 shows a method for more reliably eliminating a multipath route. In FIG. 4, the signal frequency band 40
The sweep 402 of the reference signal is performed in a frequency band equal to or wider than 1 in the frequency band. Signal frequency band 4
By performing sweep 402 wider than 01, the presence or absence of fading can be reliably checked.

(Embodiment 3) FIG. 5 shows a method of examining the presence or absence of multipath by using a signal such as an actual image, unlike a fixed reference signal as in the first and second embodiments.

Actual video signals, audio signals, and the like have different intensities and bandwidths, and since they vary with time, the state is simplified and shown as an ultra-wide band signal 507. The ultra-wide band signal 507 of the present embodiment includes three bands including a certain band signal 506 (band signal with an arrow). The spectrum information 505 in the band signal is added separately from the actual ultra-wide band signal 507 and transmitted from the transmission antenna 501.

Here, the spectrum information 50 in the signal band is obtained.
Reference numeral 5 includes the intensity information of the ultra-wide band signal 507, and compares the signal actually received by the receiver with the spectrum information in the band signal to determine the presence or absence of multipath by examining the presence or absence of multipath. . In this example, a signal obtained by sweeping the signal strength of the ultra-wide band signal 507 on the frequency axis as the spectrum information 505 in the band signal is AM-modulated and transmitted. The intensity information signal is transmitted to have the same intensity as the current sweep portion (band signal 506).

Since the spectrum information 505 in the band signal and the actual signal (band signal 506) have different frequencies, it is expected from the spectrum information 505 in the received band signal that there is a multipath like the receiving antenna 502. The signal strength (dotted line) and the actual strength (solid line) at each frequency are different. Since the receiving antennas 503 and 504 have a single path, the spectrum information and the actual signal (band signal 50
6) has the same strength.

In this method, it is possible to check the presence or absence of multipath in the entire actual channel frequency, and it is only necessary to add the spectrum information in the signal band for comparison, so that the frequency band to be used is hardly increased. be able to.

Naturally, the spectrum information 505 in the band signal
In addition, an information signal of a frequency sweep may be input, and it is possible to use an information signal other than the AM modulation. Here, the reason why the AM modulation is used is that even when the signal strength is reduced by the reflection (the receiving antenna 504), the strength signal information similarly has a reduced strength, so that there is a merit that direct comparison can be made. This method can always check all frequencies in use, unlike frequency sweeping with a fixed reference signal.

(Embodiment 4) In this embodiment, an actual operation according to the present invention will be described. Most simply, at the start of transmission or the start of reception, the presence or absence of multipath is checked once by frequency sweep. FIG. 6A shows a state of the frequency sweep. At this time, it is possible to select the most suitable antenna and then use the most suitable antenna. FIG. 6B shows a wideband signal. in this case,
This is effective when there is no shadowing, change in multipath, etc. during reception in a place where reception is very good. Here, the method is based on the frequency sweep, but the spectrum information described in the third embodiment may be used.

In the case where there is a human movement and shadowing, once at the start of transmission or at the start of reception as shown in FIG. 7 (FIG. 7A shows the frequency sweep transmitted at this time). , The presence or absence of multipath is checked by frequency sweep, and a plurality of suitable antennas are selected. Thereafter, the reference signal 60 is used at regular intervals by using the aforementioned reference signal.
The method using a strong material of No. 4 is possible. This state is shown in FIG. In this case, the received signal 60
1 is selected so that 1 can be received. Next, FIG.
If the strength of the received signal 605 is reduced by shadowing as shown in FIG.
8, an antenna that can receive another received signal 606 is used. When the operation as shown in FIG. 7 is performed, humans are mainly radio wave absorbers and are suitable for communication in the millimeter wave band where reflection is almost negligible.

Even in the case of the millimeter wave communication, when a door, a window, a blind, or another large object reflecting the millimeter wave moves, the generation of a new multipath path cannot be ignored. It is good to attach an absorber.

In this method, after the multipath is evaluated first, the evaluation is performed only with the reference signal strength, so that the configuration can be simplified. In the above example, the influence of the multipath is evaluated by the frequency sweep, but a method as in the first and third embodiments may be used.

In this embodiment, the multipath check is performed at the start of transmission or reception. However, depending on the use environment, the multipath check may be performed only when the transmission / reception method of the present invention is installed. Alternatively, it may be performed when the user feels necessary from the reception status.

(Embodiment 5) An actual antenna arrangement and a system configuration example will be described. FIG. 8A shows an example in which the direction of a directional antenna is evaluated by the above-described method at the start of transmission or at the start of reception, and the direction of the antenna is determined. An appropriate antenna direction is selected by manually changing the direction of the antenna 711 and notifying the antenna direction with light, sound or the like in the case of the favorable antenna direction 701. Of course, the antenna may be driven automatically.

FIG. 8B shows a similar example using the phased array antenna 712. Since there are no moving parts, the direction can be changed very quickly.

FIG. 8C shows a case where a plurality of directional antennas are evaluated by the above-described method, and the directional antennas are evaluated by using the methods of the third and fourth embodiments.
This is an example in which 01, 702, 703, and 704 are switched and used. This is equivalent to angle diversity. More preferably, it is most efficient if the individual antennas are movable as shown in FIG. 8 (a) and can be mutually selected after facing a preferred direction.

FIG. 8D shows a similar example in position diversity. In the case of millimeter waves, shadowing (mainly by the human body) causes fatal reception interference,
The combination with the angle diversity as shown in FIG. Because, in many cases, a plurality of transmitters are arranged relatively above, basically a direct wave is selectively received. However, if antennas are installed at both ends of the receiver, a device of a certain size can be obtained. If so, it is unlikely that the human body covers all of the antennas arranged at the plurality of locations.

FIG. 8F shows a similar example in frequency diversity. If there is enough frequency, transmitting at different frequencies from a plurality of locations (transmission directions 705 and 706) is very effective because fading due to interference between transmitters is reduced. In this case, on the receiving side, a plurality of antennas can be similarly switched and received, but it is necessary to select a transmitter (transmission direction 705) that can receive with the same antenna 713 and receive without frequency and multipath. Is also possible.

(Embodiment 6) FIG. 9 shows an example in which the transmitter 801 is a multi-beam. The receiver 805 receives the radio wave from the transmission antenna 802, but has an obstacle 806 such as a metal locker that reflects the radio wave, and avoids a path 807 (dotted line) where a multipath occurs (the transmission antenna 80).
3 is not directed toward the obstacle 806), the system can be operated more stably. Further, it is possible to transmit to a receiver 809 outside the line of sight by transmitting the signal with the antenna 804 while avoiding the obstacle 808 of the radio wave. In this case, if there is no directivity, many multipath paths are generated at the obstacle 808, and there is a possibility that the reception of the receiver 805 may be impaired. Therefore, directivity is important.

(Embodiment 7) FIG. 9 shows an example in which a plurality of transmitters are arranged, a plurality of routes from different angles, and a reception failure due to shadowing is actively avoided. Here, instead of placing a plurality of transmitters, a signal is transmitted from the transmitter 901 to the repeater 902 using the directional antenna 903, and the repeater 902 relays the signal to the receiver using the transmission / reception antenna 904. Route 905 from transmitter 901
And the path 906 from the repeater 902 is positively configured. This is a very effective method of avoiding shadowing and increasing the reliability of communication, and also increases the possibility of undesired multipath reception failure.
It is very important to evaluate whether or not multipath is performed in the method of this patent.

[0052]

According to the method of the present invention, a diversity circuit for each channel is not required, and a plurality of channels can be selected and received from a signal after processing by using an ordinary receiving device, or a plurality of receptions can be performed. Devices can be connected to receive different channels.

Further, since the information of the modulation system of the transmission signal, the channel interval, the band of each channel, and other transmission systems is not necessary for the diversity circuit, simultaneous reception is possible even for a signal in which a plurality of transmission systems are mixed. Becomes

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a wireless transmission / reception method according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of selecting an optimal transmission / reception path in the wireless transmission / reception method according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a wireless transmission / reception method according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a signal frequency band to be transmitted according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a wireless transmission / reception method according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a wireless transmission / reception method according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating a wireless transmission / reception method according to a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating a wireless transmission / reception method according to a fifth embodiment of the present invention.

FIG. 9 is a diagram illustrating a wireless transmission / reception method according to a sixth embodiment of the present invention.

FIG. 10 is a diagram illustrating a wireless transmission / reception method according to a seventh embodiment of the present invention.

FIG. 11 is a diagram illustrating a conventional wireless transmission / reception method.

[Explanation of symbols]

101, 201, 301, 501 Transmitting antennas 102, 103, 104 Receiving antennas 202, 203, 204 Receiving antennas 302, 303, 304 Receiving antennas 502, 503, 504 Receiving antennas 105, 206, 306, 507 Ultra wideband signals 106, 107 , 108 received signal 208, 210, 212 received signal 308, 310, 312 received signal 601, 602, 603, 605, 606, 607 received signal 205, 305, 604, 608 reference signal 207, 209, 211, 307, 309, 311, 6
08 received reference signal 231 reception antenna 232 RF amplifier 233 local oscillator 234 mixer 235, 236 filter 237 reference signal comparison circuit 238 switch 239 IF signal output terminal 401 signal frequency band 402 sweep 505 spectrum information in band signal 506 band signal 508 , 510, 512 Received reference signal 509, 511, 513 Received band signal 701, 702, 703, 704 Antenna direction 711, 713 Antenna 712 Phase array antenna 705, 706 Transmission direction 801 Transmitter 802, 803, 804 Transmission Antenna 805 Receiver 806, 808 Obstacle 807 Path where multipath occurs 809 Receiver 901 Transmitter 902 Repeater 903 Directional antenna 904 Transmit / receive antenna 90 5,906 routes

Claims (14)

[Claims] 1. A wireless transmission / reception method having a plurality of paths for transmitting / receiving a wideband signal including multiple channels from a transmitter to a receiver via a receiving antenna, wherein a path on which the wideband signal is not superimposed is selected by multipath. A wireless transmission / reception method, comprising: 2. The method according to claim 1, wherein the broadband signal is a millimeter wave band signal. 3. The multipath by inserting a reference signal having the same signal strength on a plurality of frequencies into the wideband signal and transmitting the signal, and selecting a path having a small signal strength difference between the received plurality of reference signals. 3. The wireless transmission / reception method according to claim 1, wherein a path on which a wideband signal is not superimposed is selected. 4. A wideband signal is transmitted by frequency sweeping a reference signal having a constant signal strength to the wideband signal, and a path having a small signal strength difference during sweeping of the received reference signal is selected, whereby the multipath causes a wideband signal. 3. The wireless transmission / reception method according to claim 1 or 2, wherein a path on which is not superimposed is selected. 5. On a frequency different from the wideband signal,
The spectrum information in the signal band is inserted and transmitted, and the difference between the frequency distribution of the wideband signal and the spectrum information in the signal band is compared by comparing the frequency distribution of the received wideband signal with the spectrum information in the signal band. The radio transmission / reception method according to claim 1 or 2, wherein a path on which a wideband signal is not superimposed by the multipath is selected by selecting a path having a smaller value. 6. A radio apparatus, wherein a path having a higher strength of the received reference signal is selected from paths on which a wideband signal is not superimposed by the multipath according to any one of claims 3 to 5. Transmission / reception method. 7. The method according to claim 3, wherein at the start of transmission or at the start of reception, a plurality of paths on which a wideband signal is not superimposed are selected by the multipath by the method according to claim 3. A radio transmission / reception method comprising: selecting a path having a higher strength of the received reference signal by inserting the reference signal into a frequency different from the above. 8. The antenna according to claim 3, wherein said antenna is movable.
A wireless transmission / reception method, wherein the direction of the antenna is selected by the method according to any one of claims 1 to 7. 9. The radio transmission / reception method according to claim 3, wherein said antenna is a phase array antenna. 10. The wireless transmission / reception method according to claim 3, wherein an arrangement of the antenna is angle diversity. 11. The wireless transmission / reception method according to claim 3, wherein an arrangement of the antenna is position diversity. 12. The wireless transmission / reception method according to claim 3, wherein an arrangement of said antennas is frequency diversity. 13. The wireless transmission / reception method according to claim 3, wherein the transmitter includes a directional antenna. 14. The wireless transmission / reception method according to claim 3, wherein the transmitter includes a plurality of or repeaters.