JP2005159629A - Radio communication system, radio communication method, and transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to set up a communicable range by limiting a specific location apart from a transmitter. <P>SOLUTION: Transmitters 1A-1D are installed at different points to transmit partial signals SA-SD in time slots corresponding to the transmitters 1A-1D among transmission signals obtained by transforming desired data, respectively. The receiver 2 receives radio waves transmitted from each transmitter 1A-1D as original transmission signals to reproduce original data from the transmission signals. The transmission power or the transmission timing is adjusted according to the arrangement position or the circuit constitution of each of transmitters 1A-1D. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless communication technique, and more particularly to a wireless communication system and a wireless communication method for performing data communication between a receiver and a transmitter located in a predetermined communicable range.

  One of the data communication methods is a spread spectrum communication method. In this spread spectrum communication system, on the transmitting side, a spread signal obtained by frequency-spreading a baseband signal to be transmitted with a spreading code composed of a pseudo-random code is transmitted, and on the receiving side, the received spread signal is transmitted on the transmitting side. The original baseband signal is demodulated by despreading with the same original spreading code as that used for frequency spreading. As a result, digital signals can be distributed over a wide band with very low power and transmitted at the same time. Even if noise occurs during communication, the noise is diffused during demodulation, so communication quality is less degraded and the transmission level is reduced. As a result, there is an effect that interference with other communications is small.

Conventionally, as such a spread spectrum radio communication system, a communication system including a transmitter and a receiver as shown in FIGS. 18 and 19 has been proposed (see, for example, Non-Patent Document 1).
On the transmitter side, as shown in FIG. 18, a carrier signal 80S is generated by a local oscillator 80, and this is multiplied by a multiplier 82 by a baseband signal 81S to be transmitted, thereby modulating the carrier signal 80S. Then, the modulated signal 82S and the spread code 83S from the spread code generator 83 are multiplied by the multiplier 84 to spread the modulated signal 82, and the obtained spread signal 84S is obtained from the power amplifier 85. The signal is amplified and transmitted from the antenna 86.

  On the other hand, on the receiver side, as shown in FIG. 19, the received signal 90S received via the antenna 90 is amplified by a low noise amplifier (LNA) 91, and then image components are removed by an image removal filter 92. The spread signal 92S and the spread code 93S from the spread code generator 93 are multiplied by a multiplier 94 to despread the spread signal 92S. The resulting modulated signal 94S and the carrier signal 95S from the local oscillator 95 are multiplied by a multiplier 96 to down-convert the modulated signal 94S to an intermediate frequency band, and the obtained intermediate frequency signal 96S is channel-converted. A desired baseband 98S is reproduced by detecting with the detector 98 via the selection filter 97.

  In such a conventional wireless communication system, when performing wireless communication, a communicable range as shown in FIG. 20 is formed. The transmission signal power from the transmitter is attenuated according to a function using the distance from the transmitter and the carrier signal frequency as parameters, and the receiver receives the signal thus attenuated. When the received signal power, that is, the electric field strength is larger than the receiver sensitivity, the receiver can demodulate the received signal. When the received signal power is lower than the receiver sensitivity, the receiver has difficulty in demodulating the received signal. .

  As shown in FIG. 20, generally, the transmission radio wave from the transmitter 8 propagates in all directions from the transmitter 8 to 360 °, and therefore the communicable range 7A of the receiver 9 that can communicate with the transmitter 8 is A circle is formed around the transmitter 8. In addition, if a directional antenna is used, the transmission direction of the transmission radio wave can be limited, and a fan-shaped communicable range 7B can be formed.

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
Hideo Ohba, Hideki Tsutsukasaka, "Wireless Communication Equipment", Nippon Riko Publishers, pp141-265, ISBN4-89019-136-4

However, in the conventional wireless communication system, as shown in FIG. 20 described above, the communicable range of the transmitter 8 and the receiver 9 is a circular communicable range 7A centering on the transmitter 8, or a fan-shaped communicable range. Although the communication range 7A and 7B includes a space between the transmitter 8 and the receiver 7, the communication range 7A and 7B includes a space between the transmitter 8 and the receiver 7. There was a problem that could not be done.
The present invention is for solving such problems, and provides a radio communication system, a radio communication method, and a transmitter that can limit a specific place away from a transmitter to be within a communicable range. The purpose is that.

  In order to achieve such an object, the wireless communication system according to the present invention is arranged at different points, and among the transmission signals obtained by converting desired data, the time interval corresponding to the transmitter is obtained. A plurality of transmitters each transmitting a partial signal as a radio wave, and a receiver that receives the radio wave transmitted from each transmitter as an original transmission signal and reproduces the original data from the transmission signal. is there.

  At this time, the transmitter may be configured to transmit a partial signal as a radio wave with a transmission power that is a demodulation limit electric field intensity at the receiver arrangement point, or from another transmitter at the receiver arrangement point. You may make it transmit a partial signal as a radio wave at the timing which becomes a transmission signal continuously with a radio wave.

  In addition, the transmitter may be arranged at a point where the radio wave transmitted from the transmitter has a demodulation limit electric field intensity at the receiver arrangement point, or the radio wave transmitted from the transmitter is located at the receiver arrangement point. You may arrange | position in the point used as a transmission signal continuously with the electromagnetic wave from another transmitter.

  As a more specific configuration, the transmitter is provided with signal generation means for generating a partial signal by converting data using a partial code consisting of a part corresponding to the transmitter of a spreading code having a predetermined code length. The receiver may be provided with demodulation means for demodulating the original data by converting a continuous transmission signal obtained by receiving radio waves from each transmitter with a spreading code having a predetermined code length.

  At this time, the transmitter may be further provided with a transmission power control unit for controlling the transmission power of the partial signal generated by the signal generation means, or the partial code using a spreading code synchronized with other transmitters. A spreading code generator for generating the signal and a timing control unit for controlling the transmission timing of the partial signal may be further provided.

  In addition, the wireless communication method according to the present invention is a transmitter arranged at different points, and among the transmission signals obtained by converting desired data, a partial signal in a time interval corresponding to the transmitter is used as a radio wave. A first step of transmitting each and a second step of receiving a radio wave transmitted from each transmitter as an original transmission signal and reproducing the original data from the transmission signal by one receiver. It is.

  In this case, the first step may be provided with a step of transmitting a partial signal as a radio wave with a transmission power having a demodulation limit electric field intensity at the receiver arrangement point. Alternatively, the receiver may be arranged in the first step. You may provide the step which transmits a partial signal as a radio wave at the timing which becomes a transmission signal continuously with the radio wave from another transmitter at a point.

  In addition, the transmitter may be arranged at a point where the radio wave transmitted from the transmitter has a demodulation limit electric field intensity at the receiver arrangement point, or the radio wave transmitted from the transmitter is located at the receiver arrangement point. You may arrange | position in the point used as a transmission signal continuously with the electromagnetic wave from another transmitter.

  As a more specific step, the first step includes a step of generating a partial signal by converting data using a partial code consisting of a part corresponding to the transmitter in a spreading code of a predetermined code length. In the second step, a step of demodulating the original data by converting a continuous transmission signal obtained by receiving radio waves from each transmitter with a spreading code having a predetermined code length may be provided.

  In this case, the first step may further include a step of controlling the transmission power of the generated partial signal, or a step of generating a partial code using a spreading code synchronized with other transmitters. The step of controlling the transmission timing of the partial signal may be further provided.

  The transmitter according to the present invention is a transmitter used in a wireless communication system that transmits desired data to a single receiver using a plurality of transmitters, and is obtained by converting desired data. In the transmission signal, a partial signal in a time interval corresponding to the transmitter is transmitted as a radio wave.

  At this time, the partial signal may be transmitted as a radio wave with a transmission power that becomes the demodulation limit electric field strength at the receiver placement point, or continuously with the radio wave from another transmitter at the receiver placement point. You may make it transmit a partial signal as a radio wave at the timing used as a transmission signal.

  Also, the radio wave to be transmitted may be placed at a point where the field strength of the demodulation limit is reached at the receiver placement point, or the radio wave to be sent is transmitted continuously from the other transmitters at the receiver placement point. You may arrange | position in the point used as a signal.

  As a more specific configuration, there may be provided signal generating means for generating a partial signal by converting data using a partial code consisting of a part corresponding to the transmitter in a spreading code having a predetermined code length.

  At this time, a transmission power control unit for controlling the transmission power of the partial signal generated by the signal generation unit may be further provided, or spreading for generating a partial code using a spreading code synchronized with other transmitters. You may further provide a code generator and the timing control part which controls the transmission timing of a partial signal.

  As described above, according to the present invention, a plurality of transmitters are arranged at different points, and among the transmission signals obtained by converting desired data, partial signals in the time interval corresponding to the transmitter are used as radio waves. Each transmitter and receiver receives the radio wave transmitted from each transmitter as the original transmission signal and reproduces the original data from this transmission signal, so the data transmitted from each transmitter is received. The communicable range that can be demodulated by the transmitter can be arbitrarily set according to the arrival conditions of the radio waves from each transmitter, for example, transmission power and transmission timing, and includes the point between the transmitter and the receiver as in the past In addition, it is possible to limit a specific place away from the transmitter to be a communicable range. Thereby, it is possible to avoid leakage of communication contents at receivers arranged at other points, and it is possible to distribute individual data for each point.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a radio communication system according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration example of a wireless communication system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the receiver according to the present embodiment. FIG. 3 is a block diagram showing a configuration of the transmitter according to the present embodiment.
This wireless communication system is composed of a plurality of transmitters 1 and one receiver 2 that are arranged at different points. In the present embodiment, a case where a spread spectrum radio communication system is configured by using four transmitters 1A to 1D and one receiver 2 will be described as an example.

[Transmitter]
The transmitter 1 (1A to 1D) is a wireless device that transmits, as radio waves, partial signals in a time interval corresponding to the transmitter among one transmission signal obtained by converting desired data.
As shown in FIG. 2, the transmitter 1 includes a spread code generator 11, a multiplier 12, a local oscillator 13, a multiplier 14, a power amplifier (hereinafter referred to as PA) 15, a band pass filter (hereinafter referred to as BPF). ) 16 and an antenna 17 are provided.

  The spread code generator 11 is a circuit unit that generates a spread code 11S at a predetermined timing based on a synchronous clock f1 distributed to each transmitter 1 via a communication network (not shown). The multiplier 12 is a circuit unit that generates a modulated signal (spread signal) 12S by frequency-spreading the baseband signal 10S by multiplying the spread code 11S and the baseband signal 10S to be transmitted. The local oscillator 13 is a circuit unit that generates a carrier signal 13S having a predetermined frequency. The multiplier 14 is a circuit unit that multiplies the modulated signal 12S and the carrier signal 13S to modulate the carrier signal 13S with the modulated signal 12S and generates a modulated signal 14S.

The PA 15 is a circuit unit that amplifies the modulated signal 14S and outputs it as a transmission signal 15S. The BPF 16 is a circuit unit that passes only a signal component of a desired frequency band in the transmission signal 15S and outputs it as the transmission signal 16S. The antenna 17 transmits the transmission signal 16S as a radio wave.
Among these, the spread code generator 11, the multiplier 12, and the multiplier 14 constitute a signal generating means.

[Receiving machine]
The receiver 2 is a wireless device that receives radio waves transmitted from the transmitters 1A to 1D as one transmission signal at a specific point and reproduces original data from the transmission signal.
As shown in FIG. 3, the receiver 2 includes an antenna 21, a bandpass filter (hereinafter referred to as BPF) 22, a low noise amplifier (hereinafter referred to as LNA) 23, a local oscillator 24, a multiplier 25, and a spread code generator. 26 and a despreading processing unit 27 are provided.

  The antenna 21 receives radio waves transmitted from the transmitters 1A to 1D and outputs them as received signals 21S. The BPF 22 is a circuit unit that passes only a signal component in a frequency band necessary for demodulation in the received signal 21S and outputs the signal as the received signal 22S. The LNA 22 is a circuit unit that amplifies the reception signal 22S and outputs it as a reception signal 23S. The local oscillator 24 is a circuit unit that generates a local oscillation signal 24S having a frequency equal to or lower than the carrier signal frequency used on the transmission side. The multiplier 25 is a circuit unit that converts (down-converts) the received signal 23S into a modulated signal (spread signal) 25S in a frequency band lower than the carrier signal frequency by multiplying the received signal 23S and the local oscillation signal 24S. .

The spread code generator 26 is a circuit unit that generates the same spread code 26S as that used on the transmission side. The despreading processing unit 27 is a circuit unit that demodulates and outputs the original baseband signal 27S by despreading the modulation signal 25S with the spreading code 26S.
Among these, the local oscillator 24, the multiplier 25, the spreading code generator 26, and the despreading processing unit 27 constitute demodulation means.

[Operation of First Embodiment]
Next, with reference to FIGS. 4-6, operation | movement of the radio | wireless communications system concerning the 1st Embodiment of this invention is demonstrated. FIG. 4 is a timing chart showing the transmission signal 16S of each of the transmitters 1A to 1D and the reception signal 21S of the receiver 2. FIG. 5 is an explanatory diagram showing the communicable range determined by the demodulation limit. FIG. 6 is an explanatory diagram showing a communicable range determined on the simultaneous arrival line.

First, each of the transmitters 1A to 1D transmits, as a radio wave, a partial signal in a time interval corresponding to each transmitter among one transmission signal obtained by converting a baseband signal to be transmitted.
In FIG. 4, a transmission signal S is one transmission signal obtained by converting a baseband signal to be transmitted, and is a signal unit capable of demodulating significant data. Each transmitter 1A-1D is assigned in advance a unique time interval T0-T1, T1-T2, T2-T3, T3-T4, and a partial signal corresponding to each time interval in the transmission signal S. A transmission signal 16S composed of SA to SD is transmitted as a radio wave.

  These transmission signals 16S arrive at the receiver 2 at a timing t0 after Δt from the transmission start timing T0. The receiver 2 receives the radio waves transmitted from the transmitters 1A to 1D in order from the time t0. Then, the partial signals SA to SD are combined by the antenna 21 to obtain the same reception signal 21S as the original transmission signal S. The reception signal 21S is converted and the original baseband signal 27S is converted. can get.

At this time, in order for the receiver 2 to demodulate the original baseband signal, it has electric field strength that allows the radio waves of the partial signals SA to SD transmitted from the transmitters 1A to 1D to be demodulated as radio wave arrival conditions. If any one of the partial signals SA to SD has insufficient limit strength, the baseband signal cannot be demodulated normally.
Therefore, for example, as shown in FIG. 5, the transmitters 1A to 1D are arranged at points PA to PD on the same circumference centered on the point Q, and the demodulation limit 3A extends from each transmitter 1A to 1D to the point Q. When the radio wave is transmitted with the same transmission power of ˜3D, the receiver 2 transmits the original baseband signal only at the point Q surrounded by the demodulation limits 3A to 3D determined by the transmission power of the transmitters 1A to 1D. Can be demodulated.

In addition, in order to demodulate the original baseband signal by the receiver 2, the radio wave of each of the partial signals SA to SD transmitted from the transmitters 1A to 1D as the radio wave arrival conditions is the time position in the original transmission signal S. If any one of the partial signals SA to SD is received at the same timing and overlapped with other partial signals, the baseband signal cannot be demodulated normally.
Therefore, for example, as shown in FIG. 6, the transmitters 1A to 1D are arranged at points PA to PD on the same circumference centered on the point Q, and the partial signals SA to SD are included from the transmitters 1A to 1D. When the radio wave is transmitted in synchronization with the transmission start timing of the transmission signal 16S, the receiver 2 receives the original baseband signal only at the point Q surrounded by the simultaneous arrival lines 4A to 4D indicating the positions where the radio wave arrival times are equal. Can be demodulated.

As described above, in this embodiment, each transmitter 1A to 1D transmits a partial signal in a time interval corresponding to the transmitter out of one transmission signal obtained by converting desired data. Since the receiver 2 receives the radio waves transmitted from the transmitters 1A to 1D as one transmission signal and reproduces the original data from the transmission signals, the electric field strength and transmission timing of these radio waves are reproduced. It is possible to communicate only at a point determined by.
Therefore, an arbitrary place away from the transmitter can be set as a communicable range without including a point between the transmitter and the receiver as in the prior art. Thereby, it is possible to avoid leakage of communication contents at receivers arranged at other points, and it is possible to distribute individual data for each point.

[Partial signal generation]
Next, with reference to FIG. 7, partial signal generation processing in each of the transmitters 1 </ b> A to 1 </ b> D will be described. FIG. 7 is a timing chart showing the generation of partial signals in each transmitter.
In a general spread spectrum system, as shown in FIG. 7, a spread signal SS is generated by frequency-spreading the baseband signal B using a spread code PN composed of a pseudo-random code in a transmitter, and this spread signal SS is generated. The transmission signal S is generated by modulating the carrier signal using.

In the present embodiment, when each of the transmitters 1A to 1D generates unique partial signals SA to SD, as shown in FIG. 7, it corresponds to the time interval pre-assigned to the transmitter of the spread code PN. The frequency spread is performed using the spreading code 11S composed of the parts to be performed, that is, the partial codes PN0 to PN3.
These spreading codes 11S are generated from the original spreading code PN by the spreading code generator 11 of the transmitters 1A to 1D based on the synchronization clock f1 distributed to each of the transmitters 1A to 1D.

The spread code 11S is composed of partial codes PN0 to PN3 and a code value “0” for masking the baseband signal 10S in other sections.
The partial codes PN0 to PN3 are obtained by dividing the original spreading code PN by the number of the transmitters 1 or more. In the example of FIG. 7, PN of 31 chips length per symbol is converted to PN0 to PN2 of 8 chips length. It is divided into 7-chip length PN3. For example, the partial code PN0 used in the transmitter 1A is composed of a code having a length of 8 chips from the beginning of the PN corresponding to the time intervals T0 to T1, and is “0” from the remaining 9th chip to the 31st chip. .

Here, when each transmitter 1A-1D frequency-spreads the same baseband signal 10S using each spreading code 11S, each transmitter 1A-1D has baseband only in the section corresponding to the partial codes PN0-PN3. Each of the signals 10S is subjected to frequency spreading. In this way, the transmission signal 16S composed of the individual partial signals SA to SD is generated based on the modulation signal 12S obtained from the multiplier 12, and these are transmitted from the antenna 117 as radio waves.
In the receiver 2, the radio wave of the transmission signal 16 </ b> S transmitted from each of the transmitters 1 </ b> A to 1 </ b> D is received by the antenna 21 in synchronization.

At this time, when the receiver 2 continuously receives the partial signals SA to SD corresponding to the partial codes PN0 to PN3 included in each transmission signal 16S, these radio waves are combined and transmitted from one transmitter. Equal to the radio wave. Therefore, the original baseband signal 27S can be demodulated by despreading using the spreading code PN.
Further, when any one of the partial signals SA to SD overlaps or separates from another partial signal by one chip or more, it is not normally despread with the spreading code PN, and the original baseband signal cannot be demodulated.

  As described above, in this embodiment, transmitters 1A to 1D frequency-spread a baseband signal using partial codes PN0 to PN3 that are part of a spread code PN having a predetermined code length and that correspond to the transmitter. Thus, the partial signals SA to SD are generated and transmitted, and the continuous reception signal 21S obtained by receiving the radio waves from the transmitters 1A to 1D is despread by the spreading code PN having a predetermined code length. By doing so, the original data is demodulated, so that the communicable range can be accurately limited with accuracy according to the chip width (chip rate) of the spread code PN.

Further, even when there is interference with radio waves from transmitters of other communication systems, a desired baseband signal can be accurately reproduced by using a unique spreading code.
Further, since the partial signals SA to SD are generated by using the partial codes PN0 to PN3 and the spreading code 11S composed of values for masking other time intervals, a general circuit configuration is not required without requiring a new circuit configuration. The partial signals SA to SD specific to the transmitters 1A to 1D can be generated with the same circuit configuration as that used in the spread spectrum system.

In the present embodiment, each transmitter 1A to 1D has been described as an example in which individual partial signals SA to SD are generated using spreading codes 11S made up of partial codes PN0 to PN3. The partial signals SA to SD may be generated with other configurations without being limited thereto.
For example, a gate circuit is provided between the multiplier 12 and the multiplier 14 of each of the transmitters 1A to 1D, the baseband signal 10S is frequency-spread using the spreading code PN, and the modulated signal 12S is generated. The multiplier 14 may generate the respective partial signals SA to SD by outputting the modulated signal 12S only in the time interval corresponding to the individual transmitters 1A to 1D in the circuit.

In the present embodiment, the case where the multiplier 14 of the transmitter 1 performs on-off keying modulation on the carrier signal 13S based on the modulation signal 12S has been described as an example. However, the present invention is not limited to this, and the modulation signal 12S is not limited thereto. As long as the carrier signal 13S is AM-modulated based on the above, any configuration can be applied.
In the present embodiment, the case where the partial signals SA to SD are generated based on the spread spectrum method has been described as an example. However, the communication method serving as a base for generating the partial signal is not limited to this, and other The partial signal may be generated based on the communication method.

[Second Embodiment]
Next, a radio communication system according to the second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram showing a configuration of a transmitter used in the wireless communication system according to the second embodiment of the present invention.
In the first embodiment described above, the case where radio waves are transmitted from the transmitters 1A to 1D with the same transmission power has been described as an example. However, in the present embodiment, the transmission power of the transmitters 1A to 1D is changed. By setting individually, the communicable range can be set to a desired point.

Compared with the first embodiment described above (see FIG. 2), the transmitter 1 (1A to 1D) is obtained by adding a transmission power control unit 18 as means for adjusting transmission power. The configuration is the same as described above. In FIG. 8, the same or equivalent parts as in FIG.
The transmission power control unit 18 outputs a control signal 18S instructing the specific transmission power set in advance to each of the transmitters 1A to 1D to the PA 15, and controls the amplification factor of the PA 15 to obtain a desired transmission power. Part.

[Operation of Second Embodiment]
Next, the operation of the radio communication system according to the second embodiment of the present invention will be described with reference to FIG. 9 and FIG. FIG. 9 is a timing chart showing the transmission signal 16S of each of the transmitters 1A to 1D and the reception signal 21S of the receiver 2. FIG. 10 is an explanatory diagram showing the communicable range determined by the demodulation limit.

In each of the transmitters 1A to 1D, the transmission power control unit 18 is set in advance with its own transmission power PW1 to PW4, and each transmission power control unit 18 has an amplification factor corresponding to the corresponding transmission power PW1 to PW4, respectively. A control signal 18S for instructing is output.
Thereby, as shown in FIG. 9, the transmission signal 16S composed of the partial signals SA to SD unique to each of the transmitters 1A to 1D is transmitted with the desired transmission power PW1 to PW4, and Δt after the transmission start timing T0. At the timing t0, the receiver 2 is reached and sequentially received.

  Here, as shown in FIG. 10, for example, the transmitters 1A to 1D are arranged at points PA to PD on the same circumference centered on the point Q, and the transmission power of the transmitters 1A and 1C is set to the first level. When the transmission power PW2 of the transmitter 1B is set larger than PW1 and the transmission power PW4 of the transmitter 1D is smaller than PW1, the transmission power of each of the transmitters 1A to 1D is The communicable range surrounded by the determined demodulation limits 3A to 3D is a point Q ′ on the transmitter 1D side from the original reception point Q.

  As described above, in this embodiment, the transmitters 1A to 1D are provided with the transmission power control unit 18 that controls the amplification factor of the PA 15, and radio waves are transmitted from the transmitters 1A to 1D with preset individual transmission power. Thus, the communicable range can be arbitrarily set without changing the installation positions of the transmitters 1A to 1D.

[Third Embodiment]
Next, with reference to FIG. 11, the radio | wireless communications system concerning the 3rd Embodiment of this invention is demonstrated. FIG. 11 is a block diagram showing a configuration of a transmitter used in the wireless communication system according to the third embodiment of the present invention.
In the first embodiment described above, the case where radio waves are transmitted from the transmitters 1A to 1D at the same transmission timing has been described as an example. However, in the present embodiment, the transmission timings of the transmitters 1A to 1D are changed. By setting individually, the communicable range can be set to a desired point.

Compared with the first embodiment described above (see FIG. 2), the transmitter 1 (1A to 1D) is provided with a timing control unit 19 between the multiplier 12 and the multiplier 14 as means for adjusting the transmission timing. The other configurations are the same as described above. In FIG. 11, the same or equivalent parts as in FIG.
The timing control unit 19 is a circuit unit that receives the modulated signal 12S generated by the multiplier 12 and outputs the modulated signal 19S to the multiplier 14 at a specific transmission timing set in advance in each of the transmitters 1A to 1D.

[Operation of Third Embodiment]
Next, the operation of the radio communication system according to the third embodiment of the present invention will be described with reference to FIG. 12 and FIG. FIG. 12 is a timing chart showing the transmission signal 16S of each of the transmitters 1A to 1D and the reception signal 21S of the receiver 2. FIG. 13 is an explanatory diagram showing a communicable range determined on the simultaneous arrival line.

In each of the transmitters 1A to 1D, unique transmission timings Δt1 to Δt4 are set in advance in the timing control unit 19, and each timing control unit 19 is delayed by a corresponding transmission timing Δt1 to Δt4 from the transmission start timing T0. The modulated signal 19S is output.
As a result, the transmission signal 16S composed of the partial signals SA to SD unique to each of the transmitters 1A to 1D is transmitted at a desired transmission timing Δt1 to Δt4 with respect to the transmission start timing T0 as shown in FIG. At the timing t0 after Δt from the start timing T0, the receiver 2 is reached and received sequentially.

  Here, as shown in FIG. 13, for example, the transmitters 1A to 1D are arranged at points PA to PD on the same circumference centered on the point Q, and the transmission timing Δt2 of the transmitter 1B is made equal to T0 ( Δt2 = 0), the transmission timings of the transmitters 1A and 1C are delayed by Δt1 (= Δt3) from T0, and the transmission timing of the transmitter 1D is delayed by Δt4 (> Δt1) from T0. The communicable range surrounded by the simultaneous arrival lines 4A to 4D determined at the transmission timing of 1D is the point Q ′ on the transmitter 1D side from the original reception point Q.

  Thus, in this Embodiment, the timing control part 19 which controls transmission timing is provided in each transmitter 1A-1D, and it transmits so that a radio wave may be transmitted from each transmitter 1A-1D at the preset individual transmission timing. Therefore, the communicable range can be arbitrarily set without changing the installation positions of the transmitters 1A to 1D.

[Fourth Embodiment]
Next, with reference to FIG. 14, the radio | wireless communications system concerning the 4th Embodiment of this invention is demonstrated. FIG. 14 is an explanatory diagram showing a communicable range determined by a demodulation limit in the wireless communication system according to the fourth embodiment of the present invention.
In the second embodiment described above, the case of adjusting the transmission power for transmitting radio waves from the transmitters 1A to 1D has been described as an example. However, in this embodiment, each transmitter 1A for a desired communicable range is described. The transmission power is individually adjusted according to the arrangement position of ˜1D, and the communicable range is set to a desired point.

The configuration diagram of the transmitters 1A to 1D used in the present embodiment, and the timing chart showing the transmission signal 16S of each of the transmitters 1A to 1D and the reception signal 21S of the receiver 2, are the diagrams of the first embodiment described above. 2 and FIG. 4, and a detailed description thereof is omitted here.
For example, as shown in FIG. 14, the transmitter 1A is arranged at a point PA on the same circumference centered on the point Q, and the transmitter 1B is moved to the point PB ′ moved from the original point PB to the inside of the circumference. The transmitter 1C is arranged at a point PC ′ moved from the original point PC to the transmitter 1D on the circumference, and the transmitter 1D is moved to the point PD ′ moved from the original point PD to the outside of the circle. When arranged, the communicable range surrounded by the demodulation limits 3A to 3D determined by the transmission power of each of the transmitters 1A to 1D is the point Q ′ on the transmitter 1D side from the original reception point Q.

  Thus, in this Embodiment, since transmission power was individually set by the arrangement position of each transmitter 1A-1D with respect to a desired communicable range, transmission power is adjusted with each transmitter 1A-1D. Therefore, the communicable range can be arbitrarily set without requiring a configuration for the above. In addition, transmission power itself in each transmitter 1A-1D may mutually be equal, and may differ.

[Fifth Embodiment]
Next, with reference to FIG. 15, the radio | wireless communications system concerning the 5th Embodiment of this invention is demonstrated. FIG. 15 is an explanatory diagram showing a communicable range determined by the simultaneous arrival line in the wireless communication system according to the fifth embodiment of the present invention.
In the third embodiment described above, the case of adjusting the transmission timing for transmitting radio waves from the transmitters 1A to 1D has been described as an example. However, in the present embodiment, each transmitter 1A for a desired communicable range is described. The transmission timing is individually adjusted according to the arrangement position of ˜1D, and the communicable range is set to a desired point.

The configuration diagram of the transmitters 1A to 1D used in the present embodiment, and the timing chart showing the transmission signal 16S of each of the transmitters 1A to 1D and the reception signal 21S of the receiver 2, are the diagrams of the first embodiment described above. 2 and FIG. 4, and a detailed description thereof is omitted here.
For example, as shown in FIG. 15, the transmitter 1A is arranged at a point PA on the same circumference centered on the point Q, and the transmitter 1B is moved to the point PB ′ moved from the original point PB to the inside of the circumference. The transmitter 1C is arranged at a point PC ′ moved from the original point PC to the transmitter 1D on the circumference, and the transmitter 1D is moved to the point PD ′ moved from the original point PD to the outside of the circle. When arranged, the communicable range surrounded by the simultaneous arrival lines 4A to 4D determined by the transmission timings of the transmitters 1A to 1D is the point Q ′ on the transmitter 1D side from the original reception point Q.

  As described above, in the present embodiment, the transmission timing is individually adjusted according to the arrangement positions of the transmitters 1A to 1D with respect to a desired communicable range, so the transmission timings of the transmitters 1A to 1D are adjusted. The communicable range can be arbitrarily set without requiring a configuration. In addition, the transmission timing itself in each transmitter 1A-1D may mutually be same, or may differ.

[Sixth Embodiment]
Next, with reference to FIG. 16 and FIG. 17, the radio | wireless communications system concerning the 6th Embodiment of this invention is demonstrated. FIG. 16: is a block diagram which shows the structure of the transmitter used with the radio | wireless communications system concerning the 6th Embodiment of this invention. FIG. 17: is a block diagram which shows the structure of the receiver used with the radio | wireless communications system concerning the 6th Embodiment of this invention.
The radio communication system according to the present embodiment includes a transmitter and a receiver that perform radio communication using a spread spectrum method without using a carrier signal.

As shown in FIG. 16, this transmitter is provided with a spread code generator 11, a multiplier 12, a signal generation means 18, a PA 15, a BPF 16, and an antenna 17, and the first embodiment described above. Compared with such a transmitter (see FIG. 2), a signal generating means 18 is provided instead of the local oscillator 13 and the multiplier 14. The signal generating means 18 suppresses a frequency component near the direct current (DC) in the modulated signal 12S from the multiplier 12, and generates a pulse signal generated in response to the rising and falling edges of the modulated signal 12S as the modulated signal 18S. Is output to PA15.
As shown in FIG. 17, the receiver includes an antenna 21, a BPF 22, an LNA 23, a spreading code generator 26, and a despreading processing unit 27. The receiver according to the first embodiment described above. Compared to (see FIG. 3), the local oscillator 24 and the multiplier 25 are omitted.

  These transmitters and receivers perform wireless communication by transmitting and receiving frequency-spread baseband signals as they are without using carrier signals, but are similar to the transmitter of the first embodiment described above. In addition, each transmitter 1A to 1D transmits, as a radio wave, a partial signal in a time interval corresponding to the transmitter among one transmission signal obtained by converting desired data. Since the radio waves transmitted from the transmitters 1A to 1D are received as one transmission signal and the original data is reproduced from the transmission signal, communication is performed only at a point determined by the electric field strength of these radio waves and the transmission timing. The first embodiment can also be applied to a wireless communication system that performs wireless communication without using a carrier signal by a spread spectrum method. Hunt.

  In the present embodiment, the case where the first embodiment is applied to a wireless communication system that performs wireless communication without using a carrier signal by a spread spectrum method has been described as an example. Similarly, this embodiment can be applied to a wireless communication system that performs wireless communication without using a carrier signal by a spread spectrum method, and the same effects as those described above can be obtained.

In addition, although each embodiment described above may be implemented independently, a plurality of embodiments may be combined.
In each embodiment, the case where the wireless communication system is configured by four transmitters and one receiver has been described as an example. However, the number of transmitters and receivers is not limited to the above. The present embodiment can be applied to any wireless communication system having at least two transmitters 1 and one receiver 2.

1 is a configuration example of a wireless communication system according to a first embodiment of the present invention. It is a block diagram which shows the structure of the transmitter used with the radio | wireless communications system of FIG. It is a block diagram which shows the structure of the receiver used with the radio | wireless communications system of FIG. It is a timing chart which shows the transmission signal of each transmitter, and the reception signal of a receiver. It is explanatory drawing which shows the communicable range determined by a demodulation limit. It is explanatory drawing which shows the communicable range determined by a simultaneous arrival line. It is a timing chart which shows the production | generation of the partial signal in each transmitter. It is a block diagram which shows the structure of the transmitter used with the radio | wireless communications system concerning the 2nd Embodiment of this invention. It is a timing chart which shows the transmission signal of each transmitter, and the reception signal of a receiver. It is explanatory drawing which shows the communicable range determined by a demodulation limit. It is a block diagram which shows the structure of the transmitter used with the radio | wireless communications system concerning the 3rd Embodiment of this invention. It is a timing chart which shows the transmission signal of each transmitter, and the reception signal of a receiver. It is explanatory drawing which shows the communicable range determined by a simultaneous arrival line. It is explanatory drawing which shows the communicable range determined by the demodulation limit by the radio | wireless communications system concerning the 4th Embodiment of this invention. It is explanatory drawing which shows the communicable range determined by the simultaneous arrival line by the radio | wireless communications system concerning the 5th Embodiment of this invention. It is a block diagram which shows the structure of the transmitter used with the radio | wireless communications system concerning the 6th Embodiment of this invention. It is a block diagram which shows the structure of the receiver used with the radio | wireless communications system concerning the 6th Embodiment of this invention. It is a block diagram which shows the structure of the transmitter used with the conventional radio | wireless communications system. It is a block diagram which shows the structure of the receiver used with the conventional radio | wireless communications system. It is an example of the communicable range by the conventional radio | wireless communications system.

Explanation of symbols

11A, 1B, 1C, 1D ... transmitter, 10S ... baseband signal, 11 ... spread code generator, 11S ... spread code, 12 ... multiplier, 12S ... modulated signal, 13 ... local oscillator, 13S ... carrier signal, 14 DESCRIPTION OF SYMBOLS ... Multiplier, 14S ... Modulated signal, 15 ... Power amplifier (PA), 15S, 16S ... Transmission signal, 16 ... Band pass filter (BPF), 17 ... Antenna, 18 ... Transmission power control part, 18S ... Control signal, DESCRIPTION OF SYMBOLS 19 ... Timing control part, 19S ... Modulation signal, 2 ... Receiver, 21 ... Antenna, 21S, 22S, 23S ... Reception signal, 22 ... Band pass filter (BPF), 23 ... Low noise amplifier (LNA), 24 ... Local oscillator 24S ... Local oscillation signal, 25 ... Multiplier, 25S ... Modulation signal, 26 ... Spreading code generator, 26S ... Spreading code, 27 ... Despreading processing unit, 27S ... Sband signal, 3A, 3B, 3C, 3D ... demodulation limit, 4A, 4B, 4C, 4D ... simultaneous arrival line, PN0, PN1, PN2, PN3 ... partial code, SA, SB, SC, SD ... partial signal, PW1, PW2, PW3, PW4 ... transmission power, Δt1, Δt2 ... transmission timing, PA, PB, PC, PD, PA ', PB', PC ', PD' ... transmission point, Q, Q '... reception point.

Claims (24)

A plurality of transmitters that are arranged at different points, respectively, and transmit a partial signal of a time section corresponding to the transmitter as a radio wave among transmission signals obtained by converting desired data;
A wireless communication system comprising: a receiver that receives radio waves transmitted from the transmitters as original transmission signals and reproduces original data from the transmission signals. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the transmitter transmits the partial signal as a radio wave with a transmission power having a demodulation limit electric field intensity at an arrangement point of the receiver. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the transmitter transmits the partial signal as a radio wave at a timing at which the transmission signal is continuous with a radio wave from another transmitter at a location where the receiver is located. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the transmitter is disposed at a point where a radio wave transmitted from the transmitter is at a demodulation limit electric field intensity at a position where the receiver is disposed. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the transmitter is disposed at a point where a radio wave transmitted from the transmitter is the transmission signal continuously with a radio wave from another transmitter at a location where the receiver is disposed. . The wireless communication system according to claim 1, wherein
The transmitter includes signal generation means for generating the partial signal by converting the data using a partial code consisting of a part corresponding to the transmitter in a spreading code of a predetermined code length,
The receiver includes demodulation means for demodulating original data by converting a continuous transmission signal obtained by receiving radio waves from the transmitters with a spreading code having a predetermined code length. A wireless communication system. The wireless communication system according to claim 6.
The wireless communication system, wherein the transmitter further includes a transmission power control unit that controls transmission power of the partial signal generated by the signal generation unit. The wireless communication system according to claim 6.
The transmitter further includes a spreading code generator that generates the partial code using a spreading code synchronized with another transmitter, and a timing control unit that controls transmission timing of the partial signal. A wireless communication system. A first step of transmitting, as a radio wave, a partial signal in a time section corresponding to the transmitter among transmission signals obtained by converting desired data in transmitters arranged at different points;
A radio communication method comprising: a second step of receiving a radio wave transmitted from each of the transmitters as an original transmission signal by one receiver and reproducing the original data from the transmission signal. The wireless communication method according to claim 9, wherein
The wireless communication method according to claim 1, wherein the first step includes a step of transmitting the partial signal as a radio wave with a transmission power that is a demodulation limit electric field intensity at an arrangement point of the receiver. The wireless communication method according to claim 9, wherein
The first step includes a step of transmitting the partial signal as a radio wave at a timing that becomes the transmission signal continuously with a radio wave from another transmitter at a location where the receiver is disposed. Method. The wireless communication method according to claim 9, wherein
The wireless communication method according to claim 1, wherein the transmitter is disposed at a point where a radio wave transmitted from the transmitter has a demodulation limit electric field intensity at a position where the receiver is disposed. The wireless communication method according to claim 9, wherein
The wireless communication method, wherein the transmitter is disposed at a point where a radio wave transmitted from the transmitter is the transmission signal continuously with a radio wave from another transmitter at a location where the receiver is disposed. . The wireless communication method according to claim 9, wherein
The first step includes the step of generating the partial signal by converting the data using a partial code consisting of a part corresponding to the transmitter in a spreading code having a predetermined code length,
The second step includes a step of demodulating original data by converting a continuous transmission signal obtained by receiving radio waves from each transmitter with a spreading code having a predetermined code length. A wireless communication method. The wireless communication method according to claim 14, wherein
The wireless communication method according to claim 1, further comprising the step of controlling transmission power of the generated partial signal in the first step. The wireless communication method according to claim 14, wherein
The radio | wireless characterized by further comprising the step which produces | generates the said partial code using the spreading code mutually synchronized with another transmitter in the said 1st step, and the step which controls the transmission timing of the said partial signal. Communication method. A transmitter used in a wireless communication system for transmitting desired data to a single receiver using a plurality of transmitters,
A transmitter characterized by transmitting a partial signal of a time section corresponding to the transmitter as a radio wave among transmission signals obtained by converting desired data. The transmitter of claim 17, wherein
A transmitter characterized in that the partial signal is transmitted as a radio wave with a transmission power that provides an electric field intensity at a demodulation limit at an arrangement point of the receiver. The transmitter of claim 17, wherein
The transmitter, wherein the partial signal is transmitted as a radio wave at a timing at which the transmission signal is generated continuously from a radio wave from another transmitter at a location where the receiver is disposed. The transmitter of claim 17, wherein
A transmitter, characterized in that a radio wave to be transmitted is disposed at a point where a demodulation limit electric field intensity is obtained at a location where the receiver is disposed. The transmitter of claim 17, wherein
A transmitter characterized in that a radio wave to be transmitted is arranged at a point where the transmission signal is continuous with a radio wave from another transmitter at the location of the receiver. The transmitter of claim 17, wherein
A transmitter comprising: signal generation means for generating the partial signal by converting the data using a partial code consisting of a part corresponding to the transmitter in a spreading code having a predetermined code length. 23. The transmitter of claim 22, wherein
The transmitter further comprising a transmission power control unit that controls transmission power of the partial signal generated by the signal generation means. 23. The transmitter of claim 22, wherein
A transmitter further comprising: a spread code generator that generates the partial code using a spread code that is mutually synchronized with another transmitter; and a timing control unit that controls transmission timing of the partial signal.

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