JP3404530B2 - Communication device, communication method, and information recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device, a communication method, and an information recording medium.

In particular, the present invention relates to a communication device and a communication method suitable for detecting the intensity and power of an interference signal in a radio wave propagation path, and a computer-readable information recording medium recording a program for realizing these.

[0003]

2. Description of the Related Art In recent years, a technique of wireless mobile communication using a mobile terminal or the like has become widespread. For this reason, the frequency bands that can be used in each wireless communication system are becoming tighter, and the same frequency band is being shared and used more and more.

On the other hand, since a large amount of data is transmitted in multimedia communication, it is necessary to use broadband transmission.
Therefore, short-range communication is mainly used, but in this case, there is a high possibility that a strong interference signal will be received from a short distance.

Further, it is becoming clear that measures such as transmission power control and modulation method control are effective for improving communication quality.

Conventionally, in such a radio communication system, when receiving a radio wave signal transmitted from another radio terminal, interference in the radio wave propagation path is detected.

[0007]

However, in a wireless communication system, if it becomes possible to detect interference around the transmitting side when transmitting a radio signal to another wireless terminal, the above-mentioned control can be performed at high speed. You can do it. Therefore, a technique for detecting such interference at high speed is desired.

The present invention has been made to solve the above problems, and is a communication device, a communication method, and a communication method suitable for performing high-speed interference detection around a transmitting terminal in a wireless communication system. It is an object of the present invention to provide a computer-readable information recording medium in which a program for realizing these is recorded.

[0009]

In order to achieve the above object, the following invention is disclosed according to the principle of the present invention.

A communication device according to a first aspect of the present invention comprises an input reception unit, a modulation unit, a transmission unit, an extraction unit, a reception unit, an acquisition unit, and a detection result output unit. To configure.

Here, the input receiving unit receives the input of the data signal.

On the other hand, the modulator modulates the data signal, the input of which is accepted, and outputs the resulting modulated signal.

Further, the transmitting section transmits the modulated signal by wireless transmission.

Then, the extraction unit extracts the zero-crossing timing of the modulated signal.

On the other hand, the receiver receives the radio wave signal.

Further, the acquisition unit acquires the strength or the power at the zero-crossing timing when the radio signal is extracted.

Then, the detection result output section outputs the acquired intensity or power as the intensity or power of the detected interference signal.

Further, the communication device of the present invention can be configured such that the acquisition unit performs the acquisition when the modulated signal is being transmitted by the transmission unit.

The communication device of the present invention further comprises a demodulation section and an output section, and can be configured as follows.

That is, the demodulation section demodulates the radio signal and outputs the resulting demodulated signal.

On the other hand, the output section outputs the demodulated signal as a data signal transmitted by radio transmission when the modulated signal is not transmitted by the transmitting section.

The communication device of the present invention further includes an attenuator, and can be configured as follows.

That is, the attenuator attenuates the radio wave signal when the modulated signal is being transmitted by the transmitter, and outputs the resultant attenuated signal.

On the other hand, the acquisition unit acquires the intensity or power at the zero-crossing timing when the attenuation signal is extracted, instead of the radio signal.

Further, in the communication device of the present invention, the attenuating unit determines the time average of the intensity or power of the modulated signal and the intensity or power of the attenuated signal during the period in which the modulated signal is transmitted by the transmitting unit. The radio signal may be attenuated so that the time average of the period becomes equal.

Further, in the communication device of the present invention, the transmitting unit and the receiving unit are coupled by a directional coupler, and the transmission of the modulation signal and the reception of the radio wave signal are performed via the same antenna. Can be configured to be exposed.

A communication method according to a second aspect of the present invention comprises an input receiving step, a modulating step, a transmitting step, an extracting step,
It is configured to include a receiving step, an acquiring step, and a detection result output step.

Here, in the input receiving step, the input of the data signal is received.

On the other hand, in the modulation step, the data signal of which the input is accepted is modulated and the resulting modulated signal is output.

Further, in the transmitting step, the modulated signal is transmitted by radio transmission.

Then, in the extraction step, the zero-crossing timing of the modulation signal is extracted.

On the other hand, in the receiving step, a radio wave signal is received.

Further, in the acquisition step, the strength or power at the zero crossing timing where the radio signal is extracted is acquired.

Then, in the detection result output step, the acquired intensity or power is output as the intensity or power of the detected interference signal.

Further, in the communication method of the present invention, the acquisition in the acquisition step can be performed when the modulated signal is transmitted in the transmission step.

Further, the communication method of the present invention comprises a demodulation step,
And an output step.

Here, in the demodulation step, the radio wave signal is demodulated and the resulting demodulated signal is output.

On the other hand, in the output step, when the modulated signal is not transmitted in the transmitting step, the demodulated signal is output as the data signal transmitted by radio transmission.

Further, the communication method of the present invention further includes an attenuation step, and can be configured as follows.

Here, in the attenuating step, when the modulated signal is being transmitted in the transmitting step, the radio wave signal is attenuated and the resultant attenuated signal is output.

On the other hand, in the acquisition step, instead of the radio signal,
The strength or power at the extracted zero-crossing timing of the attenuation signal is acquired.

Further, in the communication method of the present invention, in the attenuation step, the time average of the intensity or power of the modulation signal and the intensity or power of the attenuation signal in the period during which the modulation signal is transmitted in the transmission step. The radio signal can be attenuated so that the time average of the period becomes equal to.

In the communication method of the present invention, in the transmitting step and the receiving step, the modulated signal is transmitted and the radio wave signal is received through the same antenna by using the directional coupler. Can be configured.

A program for implementing the communication device and communication method of the present invention can be recorded on an information recording medium such as a compact disk, a floppy disk, a hard disk, a magneto-optical disk, a digital video disk, a magnetic tape, a semiconductor memory.

The program recorded on the information recording medium of the present invention is executed by a storage device, a computing device, an output device, an information processing device such as a general-purpose computer or parallel computer having an interface for wireless transmission, a mobile terminal, etc. By doing so, the above communication device and communication method can be realized.

Further, the information recording medium recording the program of the present invention can be distributed and sold independently of the information processing apparatus.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. The embodiments described below are for the purpose of explanation, and do not limit the scope of the present invention. Therefore, a person skilled in the art can adopt an embodiment in which each of these elements or all the elements are replaced with equivalent elements thereof, but these embodiments are also included in the scope of the present invention.

Further, in the following embodiments, in order to facilitate understanding, a communication device of a wireless communication system using an amplitude phase modulation method (CAM, QPSK, etc.) and a time division duplexing method (so-called “ping-pong transmission”) will be described. As described by way of example, the principle of the present invention can be similarly applied to a communication device of a wireless communication system that employs another modulation / demodulation system or a duplex system, and such an embodiment is also included in the scope of the present invention. .

(Embodiment of the Invention) FIG. 1 is a schematic diagram showing a schematic configuration of a communication device according to an embodiment of the present invention. Further, FIG. 2 shows a schematic diagram showing a schematic configuration of a conventional communication device. In these drawings, elements having the same functions are designated by the same reference numerals. Hereinafter, description will be given with reference to these drawings.

First, the function of each element when transmitting a data signal to another communication terminal will be described.

The BSG (Baseband Signal Generator) of the communication device 101 of the present invention and the conventional communication device 151;
The baseband signal generator) 102 accepts the input of the data signal, adds a unique data signal and the like necessary for identifying the wireless station in the communication partner, and passes this to the modulator 103.

The modulator 103 modulates the received data signal and passes it to an LPF (Low Pass Filter) 104. As a result, the frequency band of the signal output by the LPF 104 becomes fa as shown in the figure.
This and the LO (Local Oscillator) 105
A frequency converter (mixer) 106 couples the signal in the frequency band fo generated by the above to up-convert the frequency band.

The up-converted signal is the BPF.
After removing unnecessary frequency band noise with (Band Pass Filter) 107, PA (Power
Amplifier; power is amplified by 108,
A signal in the frequency band fa + fo is transmitted from the antenna 110 via the directional coupler 109.

Next, the function of each element when receiving a data signal from another communication terminal will be described.

The antenna 110 passes the received radio signal to the BPF 111 via the directional coupler 109. BPF
111 removes unnecessary frequency band noise and
(Radio Frequency Amplifier) 112
To amplify the signal.

Further, the frequency converter 113 has the LO 1
The signal component of frequency fo generated by 05 is removed from the output of RF 112 to down-convert the frequency band.

Further, the LPF 114 removes unnecessary high frequency band noise from the down-converted signal to obtain a signal in the frequency band fa.

This signal is demodulated by the demodulator 115,
The BSG 116 extracts a unique data signal or the like, extracts only the data signal, and outputs the transmitted data signal.

In the ping-pong transmission adopted in the conventional communication device 151, as can be seen from the time chart shown in FIG. 3, generally, when the transmission is being performed, the reception is not performed, and when the reception is being performed, Do not send.

However, let us consider the waveform of the signal when the signal transmitted by the communication device 151 is received by the communication device 151. Figure 4
FIG. 4 is an explanatory diagram showing the appearance of this waveform. Hereinafter, description will be given with reference to this figure.

As shown in FIG. 4, when the amplitude level of the transmission signal of the own station is larger than the zero point (in the case of + A), it is set to "1",
When it is smaller than the zero point (in the case of −A), it is associated with “0” and the signal is transmitted. Therefore, the point where the amplitude level crosses the zero point always appears during the transmission of the signal. This time point is called “zero crossing timing”.

When a digital signal is transmitted, the zero-crossing timing appears at the time indicated by the arrow in the figure, that is, at intervals of an integral multiple of a predetermined time.

In this embodiment, the zero point at the output of the modulator 103, the zero point at the output of the BSG 102, and the zero point at the output of the LPF 114 all match, so the zero crossing timing from the output of the BSG 102 is the same. Is extracted to extract the zero-crossing timing of the modulated signal. However, it is also possible to adopt an embodiment in which the amplitude level of the modulation signal (the output of the modulator 103 or the output of the LFP 114) is monitored and the zero-crossing timing is extracted. It is included in the scope of the invention.

Now, when there is no interference around the own station, the amplitude level of the received signal at the zero crossing timing should be zero. Therefore, this amplitude level (or power level) at the zero crossing timing is the amplitude level (or power level) of the interference signal.

In the present invention, the deviation of the intensity (amplitude) or power at the zero-crossing timing of the received signal from the zero point is detected as the intensity or power of the interference signal, and this is averaged as appropriate and output.

That is, the zero-crossing timing extractor 201
Is the zero-crossing timing (specifically, the timing at which the data signal changes from “0” to “1”, or
The timing of changing from “1” to “0”) is extracted.

In the communication device 101, a highly accurate timing generation source such as a crystal oscillator is used for signal generation timing (not shown). Therefore, the extraction of the zero-crossing timing can be performed with extremely high accuracy.

Then, the extraction switch 202 is controlled according to the extracted timing, and the extraction switch 202 is turned on at the zero-crossing timing, and if not, OF
Set to F.

On the other hand, since the signal transmitted by the local station is received by the local station, there is a possibility that the high frequency signal is oversaturated.
Therefore, when an interference wave is detected using the reception switch 203, the received signal is passed through an ATT (ATTenator) 204 to take measures against oversaturation.

FIG. 5 is a time chart of transmission / reception and switching of each switch in the communication device 101. Hereinafter, description will be given with reference to this figure.

As shown in the figure, in the communication device 101, the receiving switch 203 is set to a when the local station is receiving, the receiving switch 203 is set to b when the local station is transmitting,
Each can be switched.

The extraction switch 202 is turned on at the zero-crossing timing, and turned off otherwise.

As shown in the figure, in the present embodiment, the zero crossing timings are arranged at intervals of an integral multiple of a predetermined time between the transmission times.

The interference signal level can be obtained by averaging the intensity (amplitude) or power of the received signal at the zero-crossing timing extracted in this way by the averaging unit 205.

As long as the zero-crossing timing can be accurately extracted, even if a communication method is adopted in which the timing is not arranged at intervals of an integral multiple of a predetermined time, the same applies. The principles of the present invention can be applied.

(Theoretical Background) FIG. 6 is an explanatory diagram showing how the result obtained in this embodiment relates to the interference signal level. Note that, in this figure, elements having the same functions as those in the above figures are denoted by the same reference numerals. The elements shown in this explanatory diagram represent the communication device 101 in the above diagram by an equivalent low-frequency system model. Hereinafter, description will be given with reference to this figure.

Since the interference wave signal level is detected when transmitting the data signal, the level of the received data signal is
Let it be Rt (t). The amplification factor of PA 108 is Gt. The gain of the antenna 110 is Ag, and the interference wave signal level is Pi.
(t) and the amplification factor of ATT 204 is Att. Further, the amplification factor of RF 112 is Gr.

In this way, the received signal level Rr (t) of the received data signal of its own station can be expressed as follows. Rr (t) ² = Rt (t) ² GtGr / Att + Pi (t) AgGr / Att

Since the detectable interference wave signal level is Rt (t) = 0 in the received signal level Rr (t), it can be expressed as follows. Ri (t) ² = Pi (t) AgGr / Att

Here, when the amplification factor Att of the ATT 204 is a constant value, AgGr / Att is a constant, and therefore the following relationship is established. Ri (t) ² ∝ Pi (t)

Further, let us consider a case where a general automatic attenuation function, which has been conventionally used, is used such that the amplification factor Att of the ATT 204 is adaptively changed according to the received signal level as follows. Note that Ave [•] means to take a time average. Ave [Rr (t) ² ] = Ave [Rt (t) ² ]

In general, the interference wave signal level is considered to be smaller than the transmission signal level, so the following assumption can be made. Rt (t) ² GtGr / Att >> Pi (t) AgGr / Att

In this case, the following holds. Att = GtGr

Therefore, the following relationship is established. Ri (t) ² = Pi (t) / Ag / Gt ∝ Pi (t)

As described above, in any case, it is understood that the detected signal level (power) has a proportional relationship with the actual interference signal level (power).

Even if such a model is not adopted, the communication device 101 is placed in a known interference signal level and the correspondence with the detection result is investigated in advance, and the interference signal level is used by using this correspondence. May be the result of actual detection.

[0087]

As described above, according to the present invention,
To provide a communication device, a communication method, and a computer-readable information recording medium which records a program for realizing these, in a wireless communication system, for performing high-speed interference detection around a transmitting terminal. You can

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a communication device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of a conventional communication device.

FIG. 3 is a time chart showing how a conventional communication device transmits and receives.

FIG. 4 is an explanatory diagram showing a relationship between a signal state and a zero-crossing timing when a signal transmitted by the local station is received by the local station.

FIG. 5 is a time chart showing how the communication device according to the embodiment of the present invention transmits and receives.

FIG. 6 is a schematic diagram showing the communication device according to the embodiment of the present invention by an equivalent low-frequency system model.

[Explanation of symbols]

101 Communication device according to an embodiment of the present invention 102 BSG 103 modulator 104 LPF 105 LO 106 frequency converter 107 BPF 108 PA 109 directional coupler 110 antenna 111 BPF 112 RF 113 Frequency converter 114 LPF 115 demodulator 116 BSG 151 Conventional Communication Device 201 Zero-crossing timing extractor 202 extraction switch 203 Receive switch 204 ATT 205 Average part

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 17/00 H04B 1/04 H04B 7/26

Claims (19)

(57) [Claims] 1. An input accepting unit for accepting an input of a data signal, a modulator for modulating the data signal for which the input is accepted and outputting a resulting modulated signal, and transmitting the modulated signal by wireless transmission. A transmitting unit, an extracting unit that extracts the zero-crossing timing of the modulated signal, a receiving unit that receives a radio signal, an acquiring unit that acquires the intensity or power of the radio signal at the extracted zero-crossing timing, A detection result output unit that outputs the acquired strength or power as the strength or power of the detected interference signal. 2. The communication device according to claim 1, wherein the acquisition unit acquires the modulated signal while the modulated signal is being transmitted by the transmitting unit. 3. A demodulation section for demodulating the radio wave signal and outputting a resulting demodulation signal, and data transmitted by radio transmission of the demodulation signal when the modulation signal is not transmitted by the transmission section. The communication device according to claim 2, further comprising: an output unit that outputs as a signal. 4. An attenuator for attenuating the radio wave signal when the modulated signal is being transmitted by the transmitter, and outputting the resultant attenuated signal, wherein the acquiring unit replaces the radio wave signal. The communication device according to claim 3, wherein the intensity or power of the attenuation signal at the extracted zero-crossing timing is acquired. 5. The attenuator, for the period during which the modulated signal is transmitted by the transmitter, a time average of the intensity or power of the modulated signal during the period, and the period of intensity or power of the attenuated signal during the period. The communication device according to claim 4, wherein the radio wave signal is attenuated so that the time average of is equal to. 6. The transmitting unit and the receiving unit are coupled by a directional coupler, and the transmission of the modulated signal and the reception of the radio wave signal are performed via the same antenna. The communication device according to claim 1, wherein the communication device is a communication device. 7. An input accepting step of accepting an input of a data signal, a modulating step of modulating the data signal of which the input is accepted and outputting a resulting modulated signal, and transmitting the modulated signal by wireless transmission. A transmitting step, an extracting step of extracting the zero-crossing timing of the modulated signal, a receiving step of receiving a radio signal, an acquiring step of acquiring the intensity or power of the radio signal at the extracted zero-crossing timing, And a detection result output step of outputting the acquired intensity or power as the intensity or power of the detected interference signal. 8. The communication method according to claim 7, wherein the acquisition in the acquisition step is performed when the modulated signal is being transmitted in the transmission step. 9. A demodulation step of demodulating the radio wave signal and outputting a resulting demodulation signal; and, when the modulation signal is not transmitted in the transmission step, the demodulation signal is transmitted by radio transmission. The communication method according to claim 8, further comprising: an output step of outputting as a data signal. 10. The method further comprises an attenuating step of attenuating the radio signal when the modulated signal is being transmitted in the transmitting step, and outputting a resulting attenuated signal, wherein in the obtaining step, the radio signal is converted to the radio signal. 10. Instead, the intensity or power at the extracted zero-crossing timing of the attenuation signal is acquired, and the communication method according to claim 9. 11. In the attenuating step, for a period during which the modulated signal is transmitted in the transmitting step, a time average of the intensity or power of the modulated signal and a period average of the intensity or power of the attenuated signal. The communication method according to claim 10, wherein the radio signal is attenuated so that the time average of the periods becomes equal to. 12. In the transmitting step and the receiving step, transmission of the modulated signal and reception of the radio wave signal are performed using a directional coupler through the same antenna. The communication method according to any one of claims 7 to 11. 13. A computer (Digital Signal Processor (DSP) and FPG)
Includes A (Field Programmable Gate Array). ), An input receiving unit that receives an input of a data signal, a modulation unit that modulates the data signal that has received the input and outputs a resulting modulated signal, a transmitting unit that transmits the modulated signal by wireless transmission, An extraction unit that extracts the zero-crossing timing of the modulation signal, a reception unit that receives a radio signal, an acquisition unit that acquires the intensity or power of the radio signal at the extracted zero-crossing timing, and the acquired intensity or power. Is a computer-readable information recording medium having a program recorded thereon, which functions as a detection result output unit that outputs the detected interference signal strength or power. 14. The program in the computer, when the modulated signal is being transmitted by the transmitting unit,
The information recording medium according to claim 13, characterized in that the information recording medium is caused to function so as to be acquired by the acquisition unit. 15. The program causes the computer to demodulate the radio wave signal and output a resulting demodulated signal; and when the modulated signal is not transmitted by the transmitter, the demodulator The information recording medium according to claim 14, further functioning as an output unit that outputs a signal as a data signal transmitted by wireless transmission. 16. The program causes the computer, when the modulated signal is transmitted by the transmitting unit,
The radio signal is attenuated, and further functioned as an attenuator that outputs a resultant attenuation signal, and the acquisition unit replaces the radio signal with the intensity or power at the extracted zero-crossing timing of the attenuation signal. The information recording medium according to claim 15, wherein the information recording medium is caused to function to acquire. 17. The computer program according to claim 17, wherein the attenuating unit is configured such that, for a period during which the modulation signal is transmitted by the transmitting unit, a time average of intensity or power of the modulation signal during the period, and the attenuation. 17. The information recording medium according to claim 16, wherein the information recording medium is caused to function so as to attenuate the radio wave signal so that the signal intensity or the time average of the power in the period becomes equal to. 18. In the computer, the transmission unit and the reception unit are coupled by a directional coupler, and the transmission of the modulation signal and the reception of the radio wave signal are the same. 18. A device as claimed in any one of claims 13 to 17, characterized in that it is operated as if via an antenna.
The information recording medium described in the item. 19. The information recording medium is a compact disc, a floppy (registered trademark) disc, a hard disc, a magneto-optical disc, a digital video disc, a magnetic tape, or a semiconductor memory. The information recording medium according to any one of 1.