JPH1117604A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform communication even when a mobile communication equipment is positioned in a blind zone by receiving radio waves outputted from a satellite by plural antennas and radio-transmitting the one of maximum reception strength among the reception output to a spot affected by an obstacle. SOLUTION: Plural antennas 1 and 2 are installed so as to be turned to the visible range (orbit) of the satellite at all times, at a spot unaffected by obstacles which become the cause for blind zone generation, on the roof of a building B1 for instance. The satellite is captured by the plural antennas 1 and 2, the one of the maximum radio wave (signal) strength in the installed antennas 1 and 2 is selected at all times, and signals are transmitted from the antennas up to portable terminal equipment 8a and 8b. Thus, since it is communication within a perspective by direct waves, interference hardly occurs, and the need for connection construction from the installed place of the antennas 1 and 2 to the portable terminal equipment 8a and 8b is eliminated. Thus, even if the portable terminal equipment 8a and 8b are positioned inside the blind zone, continuous communication is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna system, and more particularly to an antenna system for receiving radio waves transmitted from a mobile communication satellite.

[0002]

2. Description of the Related Art Generally, satellite communication is performed when a mobile terminal (portable terminal) is located in a visible range of a satellite used for communication, that is, in a range where radio waves can reach. Conventionally, as shown in FIG. 3A, since the satellite S to be used is a geostationary satellite, the visible range 30 is fixed.

However, as shown in FIG. 3 (b), the satellites S1 and S2 used for mobile communication are orbiting, so that the visible ranges 31 and 32 are restricted by the time zone. . Therefore, when performing communication continuously, it is necessary to enter the visible range of the plurality of satellites S1 or S2 existing on the orbit 40. In FIGS. 3A and 3B, E is the earth, and 8 is a mobile terminal.

As described above, in mobile satellite communication, continuous communication is enabled by sequentially capturing satellites orbiting in the same orbit and entering the visible range. However, in practice, if there is a building around the location where the mobile terminal is used, or if the mobile terminal moves into a valley or mountainous area, these will become obstacles and will cause a gap until the next satellite enters the visible range. Time (where radio waves do not arrive directly or indirectly) occurs. Therefore, unless the communication position is changed in order to capture the next satellite, continuous communication cannot be performed.

That is, as shown in FIG. 4, when the terminal 8 is located at a point between the buildings B1 and B2, the radio wave range 41 of the satellite S1 and the satellite S2
Is not located in any range of the radio wave reach range 42 of FIG. Therefore, since the satellite cannot be captured at the position of the terminal 8 in the figure, communication cannot be performed.

Japanese Patent Laid-Open No. 57-116443 discloses a transceiver, a plurality of antennas, a switching circuit for selecting this antenna and connecting it to a receiver, and a circuit for driving this at a predetermined period. And a stop circuit for stopping the operation of the drive circuit when the electric field strength of one selected antenna exceeds a predetermined value. In such an apparatus, a plurality of antennas are installed in a wireless base station, and the antennas are selected at predetermined intervals by the operation of a switching circuit and a driving circuit, and are connected to a receiver. When the received electric field strength of the selected antenna exceeds a certain level, the operation of the switching circuit is stopped.

[0007] A plurality of antennas are provided in a radio communication apparatus, and all antennas are used for transmission, and any one of the antennas is selected and used for reception. To increase the communication range.

[0008]

The prior art described in the above publication has the following disadvantages. That is, the condition is that a direct wave or a reflected wave arrives at the antenna unit of the wireless device, and is not suitable for a place where a radio wave does not arrive (a blind spot).

Also, depending on the electric field strength, it is necessary to make the shape of the antenna large, and when the wireless device is a portable device, it is difficult to carry it. In addition, wired work from the antenna installation location to the wireless device is required, resulting in an increase in construction costs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has as its object to provide an antenna system which enables communication even when a mobile communication device is located in a blind spot. is there.

[0011]

SUMMARY OF THE INVENTION An antenna system according to the present invention comprises first and second antennas installed at points where radio waves output from a satellite can be received without being affected by obstacles, and the first and second antennas are provided. Selecting means for wirelessly transmitting the reception output of the second antenna having the highest reception intensity to a point affected by the obstacle.

Further, the selection means is provided corresponding to the first and second antennas and detects the intensity of the reception output of the corresponding antenna, respectively, and selects the largest one of the detection outputs. It is characterized by including a switch and a transmitting antenna for transmitting an output of the switch. The radio wave output from the satellite is a radio wave for communication between mobile communication devices.

In short, the antenna system receives a radio wave output from a satellite by a plurality of antennas, and wirelessly transmits a radio wave having the highest reception intensity among the reception outputs to a point affected by an obstacle. It is. This allows
The blind spot can be eliminated without changing the shape of the mobile communication device itself.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the antenna system according to the present invention. In this figure, the same parts as those in FIGS. 3 and 4 are indicated by the same reference numerals,
A detailed description of that part is omitted.

As described above, if there is a building or the like around the place where the portable terminal is used, it becomes an obstacle and a blank time occurs before the portable terminal enters the visible range of the next satellite. Therefore, in order to prevent this, in this system, a plurality of antennas 1 and 2 are installed at a point where there is no obstacle (the roof of a building or a mountaintop) to capture a satellite, and the installed antennas 1 and 2 are used.
2, the radio wave (signal) having the highest strength is always selected, and the signal is transmitted from the antenna to the portable terminal. By doing so, continuous communication becomes possible even when the portable terminals 8a and 8b are located in the blind area.

That is, as shown in FIG. 1, a plurality of points which are not affected by an obstacle causing a blind spot, for example, the roof of a building B 1, always face the visible range (orbit) of the satellite. The antennas 1 and 2 are installed. As shown in FIG. 2, detectors (DET) 4 and 5 are connected to these antennas 1 and 2, respectively. The detectors 4 and 5 detect the reception intensity of radio waves (signals) for each antenna, and transmit them to the switching controller (CONT) 7. The switching controller 7 compares the detection signals 6 and outputs a selection signal for selecting the output of the antenna having the maximum strength. Thereby, the switch 70 in the switch 7 connects the transmission line connecting the antenna and the antenna 3. Therefore, a transmission path from the satellite to the portable mobile terminals 8a and 8b is formed by wireless transmission.

As described above, according to the present antenna system, the antenna is installed at a point which is not affected by the obstacle causing the dead area, and the radio signal is transmitted to the communication terminal. For this reason, direct-wave line-of-sight communication is used, so that interference is less likely to occur, and connection work from the antenna installation location to the communication device is not required. Further, the communication terminal itself may have the same shape (configuration) as it is. In addition, if the output radio wave of the antenna for the communication device is within the visible range, connection to a plurality of communication terminals becomes possible without requiring additional work of signal branching and combining processing.

Since the present system includes only the antenna section, the system can be downsized. The present invention is applicable regardless of the shape of the antenna other than the parabolic antenna.

In the above, a case has been described in which two antennas capable of receiving radio waves from satellites are provided, but it is clear that three or more antennas may be provided. In such a case, a detector may be provided for each antenna to detect the reception intensity of the corresponding antenna, and the output of the antenna having the highest detected reception intensity may be switched and output by the switch.

The present invention can also take the following aspects in connection with the description of the claims.

(1) The plurality of receiving antennas are installed on the roof of a building.
3. The antenna system according to any one of 3.

(2) The antenna system according to any one of claims 1 to 3, wherein the plurality of receiving antennas are installed on a mountaintop.

[0024]

As described above, according to the present invention, a radio wave output from a satellite is received by a plurality of antennas, and of these reception outputs, the one having the highest reception intensity is determined at the point affected by the obstacle. By performing wireless transmission, there is an effect that good communication can be performed without any blind spots without changing the mobile communication device itself.

[Brief description of the drawings]

FIG. 1 is a diagram showing a usage example of an antenna system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an antenna system according to an embodiment of the present invention.

3A and 3B are diagrams illustrating an example of a satellite communication system, in which FIG. 3A illustrates a case of a geostationary satellite, and FIG. 3B illustrates a case of a mobile satellite.

FIG. 4 is a diagram illustrating a state in which a blind spot occurs.

[Explanation of symbols]

 1,2,3 Antenna 4,5 Detector 7 Switching Controller 8,8a, 8b Terminal

Claims (3)

[Claims] 1. A first and a second antenna installed at a point where radio waves output from a satellite can be received without being affected by an obstacle, and a reception intensity of a reception output among the first and second antennas. Selecting means for wirelessly transmitting the largest one to a point affected by the obstacle. 2. The detector according to claim 1, wherein said detector is provided in correspondence with said first and second antennas and detects the intensity of the reception output of each of the corresponding antennas. The antenna system according to claim 1, further comprising: a switch that performs switching, and a transmission antenna that transmits an output of the switch. 3. The antenna system according to claim 1, wherein the radio wave output from the satellite is a radio wave for communication between mobile communication devices.