JPH01136432A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To send information surely with excellent S/N by constituting a channel for plural frequencies with a radio wave of minute power between a relay means and a reception means and adding outputs of the reception means. CONSTITUTION:A radio wave in a frequency f1 sent by a transmitter 1 is received by plural relay devices 2, 3... arranged near the transmitter 1. The repeaters 2-4 send respectively the radio wave received in the frequencies f2-f4 different from each other again. The radio wave in the frequencies f2-f4 sent by the repeaters 2-4 is received by reception sections 6-8, demodulated and outputted to an adder 10. Thus, even when the transmission power is decreased to a degree to satisfy the condition of the electric field strength enabling unpermitted communication, random noise is cancelled and the power transmission with excellent S/N is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless communication device, and particularly to a wireless communication device that performs communication using weak power.

[Prior Art J] In the field of wireless communication using radio waves, various types of information such as audio, images, and other data are transmitted and received. In wireless communication, various conditions such as frequency and transmission power are regulated by law, and it is impossible for anyone to transmit using a desired frequency and transmission power without permission.

However, wireless stations with low transmission power, for example, wireless stations with a field strength of 15 ILV/m or less at room distance, can be operated without permission, and their modulation methods can be freely selected. Therefore, devices using such weak radio waves are widely used in wireless microphones and the like.

[Problems to be Solved by the Invention] However, the electric field strength described above is not necessarily strong enough for practical use, and cannot be used for applications that require reliability. Ideally, it would be desirable to be able to communicate over long distances with the minimum amount of radiated power, and it goes without saying that it would be better to be able to communicate reliably with an electric field strength that does not interfere with other communications as mentioned above. stomach.

[Means for Solving the Problems] In order to solve the above problems, the present invention includes a transmitting means for transmitting information using radio waves of a predetermined frequency and weak power, and a method for receiving the radio waves transmitted by the transmitting means. a plurality of relay means for transmitting information received using radio waves of different frequencies and weak power; a plurality of reception means for receiving radio waves of different frequencies transmitted from these plurality of relay means; A configuration consisting of an addition output means for adding and outputting the received outputs of the means is adopted.

[Operation] According to the above configuration, communication channels of a plurality of frequencies are established between the relay means and the reception means. Random noise can be removed by adding the outputs of multiple receiving means,
Furthermore, even if the transmission condition of a communication channel of a certain frequency is poor, information can be reliably transmitted with a good S/N ratio via another communication channel.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the structure of a communication system employing the present invention. In FIG. 1, the reference numeral 1 indicates a transmitter that modulates a carrier wave of a predetermined frequency using a predetermined modulation method and transmits the modulated signal with weak power. The information used to modulate the carrier wave may be various information such as audio, image, and character data, and the modulation method may be amplitude modulation, frequency modulation, or other various methods.

The transmission power of the transmitter I is preferably set to a value that satisfies the field strength conditions described in the section on the conventional example.

A radio wave having a frequency fl transmitted by the transmitter 1 is received by a plurality of repeaters 2, 3.4 (...) placed near the transmitter 1. The distance between transmitter 1 and repeaters 2 to 4 is transmission 4
! ! Set it at a distance where you can receive the radio waves transmitted from No.1. The repeaters 2 to 4 retransmit the received radio waves at different frequencies f2, f3, and f4, respectively. At this time, the transmission power of each repeater is also preferably set so as to satisfy the above-mentioned field strength condition.

Radio waves of frequencies f2, f3, and f4 transmitted by repeaters 2 to 4 are received by receivers 6.7 and 8. Receiving section 6
.about.8 demodulate the received radio waves using a demodulation method corresponding to the modulation method at the time of transmission, and output the demodulated signals to the adder IO. Adder 10 adds input signals and outputs the result from output terminal 11. The receivers 6 to 8 do not necessarily have to perform demodulation; for example, they may output an intermediate frequency signal to the adder IO and perform demodulation at a stage subsequent to the adder 10.

Receiving units 6 to 8 and adder IO constitute a receiver.

According to the above configuration, even when the transmitter 1 that transmits radio waves and the repeaters 2 to 4 transmit power are reduced to a level that satisfies the field strength conditions that allow unauthorized communication, the repeater and the receiver A plurality of communication paths using radio waves with frequencies f2 to f4 are constructed between the parts, and the received outputs of these communication paths □ are added together and output, so the addition process cancels out random noise and improves the SIN ratio. It is possible to perform good electric transmission. Even if the repeater and receiver are relatively far apart and reception conditions are poor, multiple frequency bands are used and the same demodulated signals are added together.
The reliability of electrical transmission can be increased. - The above configuration can be widely used for transmitting and receiving audio, images, and various other data. In addition, if the electric field strength conditions for unlicensed stations are satisfied as described above, wireless communication can be easily performed using small-scale, simple, and inexpensive transmitters and repeaters without the need for troublesome permission applications. Ru.

Although the above embodiment shows an example in which three repeaters are set, the number of repeaters may be larger than this. Moreover, you may provide another repeater in multiple stages between the repeaters 2-4 and the receiving parts 6-8.

This allows the reach distance to be further extended.

Moreover, although the structure for one-way communication from the transmitting side to the receiving side has been shown above, a similar configuration can be used when two stations share a transmitting/receiving section. Further, in the case of GI, full-duplex communication can be performed by setting the frequencies of all relay radio waves to different values depending on the communication direction.

Furthermore, if the communication range is relatively narrow and there is a high possibility that the output of the transmitting fit can be received as is, a configuration as shown in FIG. 2 may be considered. Figure 2 shows a transmitter l in the configuration of Figure 1.
A reception frequency receiving section 9 is added which can directly receive radio waves of frequency f1 emitted by. The demodulated outputs of the receivers 6 to 9 are input to an adder 10, and similarly output from an output terminal 11.

According to such a configuration, the S/N ratio can be further improved compared to the above embodiment. However, repeater 2
4, if there is an internal delay time and there is a time difference between the communication units 6 to 8 and 9, a circuit that delays the output of the repeaters 6 to 8 for a predetermined period of time may be inserted.

Various modifications as described above can be applied to the configuration shown in FIG. 2 as well.

[Effects of the Invention] As is clear from the above, according to the present invention, there is a transmitting means for transmitting information using radio waves of a predetermined frequency and weak power, and a transmitting means for receiving radio waves transmitted by the transmitting means, each having a different frequency and a weak power. A plurality of relay means for transmitting information received using radio waves with weak power, a plurality of reception means for receiving radio waves of different frequencies transmitted from these plurality of relay means, and a summation of the reception outputs of these plurality of reception means. Since it adopts a configuration consisting of an addition output means that outputs the information, the information is transmitted via multiple communication channels established between multiple repeaters and receivers, and the outputs of the multiple receivers are summed. By doing so, the S/N ratio can be improved and information can be transmitted reliably with low transmission power. Further, by setting the transmission power of the transmitting and relaying means to satisfy a predetermined field strength condition, there is an excellent advantage that it is possible to provide an inexpensive communication system for local use that can be easily operated without permission.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wireless communication device adopting the present invention;
FIG. 2 is a block diagram showing a modification of the configuration of FIG. 1.

Claims (1)

[Claims] A transmitting means that transmits information using radio waves of a predetermined frequency and weak power; a plurality of relay means that receive the radio waves transmitted by the transmitting means and transmit the received information using radio waves of different frequencies and weak power; A wireless communication device comprising: a plurality of receiving means each receiving radio waves of different frequencies transmitted from a plurality of relay means; and an addition output means adding and outputting received outputs of the plurality of receiving means.