JP2005277910A - Wireless communication apparatus, wireless communication method, and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus for transmitting / receiving different data through two systems of diversity systems when the state of a radio propagation path is excellent so as to increase a transmission capacity. <P>SOLUTION: A switch 11 opposed to a transmitter outputs either of transmission data D11 and D12 depending on a control signal from a receiver side. A level detector 23 at the receiver side monitors the received power of a receiver 22 and transmits a detection output. A phase shift amount of a phase shifter 24 is controlled on the basis of a phase difference denoted by an output of a phase detector 25. When discriminating that the state of radio wave propagation (channel quality) is excellent on the basis of a received electric field detected by the level detector 23, a control unit 27 transmits a control signal for stopping diversity operation to a transmitter side switch 11 and receiver side switches 28, 29. When discriminating that the channel quality is not excellent, the control unit 27 transmits a control signal denoting the use of diversity operation to transmitter side switches 11, 28 and 29. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio communication apparatus and a radio communication system, and more particularly to a radio communication apparatus and a radio communication system that can effectively use a frequency band by increasing a transmission capacity when radio wave propagation is good.

  In the conventional digital radio communication system, the space diversity system or the frequency diversity system is used as a means for overcoming the deterioration of the line quality due to attenuation (selective fading) of the received electric field due to reflection or refraction of radio waves. . Each of these diversity schemes combines signals that have passed through two or more paths in a section where reception level reduction due to selective fading and intersymbol interference can be considered, thereby reducing deterioration in channel quality. As an example, it is shown that the S / N ratio is improved by combining signal components after controlling two signals received in two frequency bands in phase (see, for example, Patent Document 1). ).

  However, in this conventional frequency diversity combining method, a different frequency band is used in each path regardless of the fading state of the radio wave propagation path, and therefore a frequency band twice or more is always required.

JP 2002-319879 A

  The conventional wireless communication apparatus described above has a drawback that it always requires a frequency band that is twice or more the signal frequency band regardless of the fading status of the radio wave propagation path.

  An object of the present invention is to provide a wireless communication apparatus capable of effectively using a frequency band by eliminating such conventional drawbacks.

  The wireless communication apparatus of the present invention is a wireless communication apparatus having an antenna, a plurality of transmission / reception means, and a control unit that determines channel quality, and the control unit determines that the channel quality is good from the radio wave propagation status and is good. In the case where the antenna and the plurality of transmission / reception means control the switching operation of the own device and the opposite device so that different data are transmitted and received, and the line quality is judged unsatisfactory, the diversity method It is characterized by controlling the switching operation for transmission / reception.

  Further, the control unit controls the switching operation based on each signal level received by the plurality of transmission / reception means.

  Further, the control unit controls switching operation based on an error rate of individual signals or combined signals received by the plurality of transmission / reception means.

  Further, the wireless communication method of the present invention is a wireless communication method of a wireless communication device having a plurality of transmission / reception functions that can be transmitted / received at the same time, whether to transmit / receive the same signal or to transmit / receive different signals according to radio wave propagation conditions. It is characterized by switching control.

  The switching control is characterized in that the switching operation is controlled based on the respective signal levels received by the plurality of transmission / reception means.

  Further, the switching control is characterized in that the switching operation is controlled based on an error rate of individual signals or combined signals received by the plurality of transmitting / receiving means.

  The wireless communication system of the present invention is characterized in that the opposing wireless communication devices are configured based on the above-described wireless communication method.

  According to the wireless communication device and the wireless communication system of the present invention, when the fading state of the radio wave propagation path is good, there is an effect that the frequency band can be effectively used by doubling the transmission capacity.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a radio communication system according to an embodiment of the present invention.

  The present embodiment shown in FIG. 1 includes a switch 11, transmitters 12a and 12b, and a combiner 13 on the transmission side. On the receiving side, the duplexer 21, the receivers 22a and 22b, the level detectors 23a and 23b, the phase shifter 24, the phase detector 25, the combiner 26, the switches 28 and 29, It is comprised from the control part 27. FIG.

  Next, the operation of the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 shows relevant portions for explaining the gist of the present invention.

  According to FIG. 1, the transmission-side switch 11 receives transmission data D11 and D12, and transmits either transmission data D11 or D12 to the transmitter based on the control signal notified from the control unit 27 of the opposite receiving station. To 12b. When the control signal indicates diversity operation, control is performed to pass the signal D11, and when the control signal indicates non-diversity operation, control is performed to pass the signal D12.

  The transmitters 12a and 12b output frequency signals fa and fb obtained by converting the transmission data D11 or D12 in the intermediate frequency band or the baseband band into a radio frequency band.

  The combiner 13 combines the two frequency signals fa and fb and outputs them to the antenna 40.

  On the other hand, the duplexer 21 on the receiving side demultiplexes the two frequency signals fa and fb received by the antenna 50 and outputs them to the receivers 22a and 22b, respectively.

  The receivers 22a and 22b frequency-convert the radio frequency band signals fa and fb into an intermediate frequency band or a baseband band and output the signals.

  The level detectors 23 a and 23 b detect the reception power level and send the detection result to the control unit 27.

  The phase shifter 24 is controlled by the output of the phase detector 25 so that the phase delays of the outputs of the receivers 22a and 22b coincide.

  The phase detector 25 detects the phase difference between the outputs of the receivers 22a and 22b, and sends a control signal that brings the phase difference close to zero to the phase shifter 24.

  The synthesizer 26 synthesizes the signals whose phase differences are controlled and sends them to the switch 28.

  The switch 28 is controlled so as to output the synthesized signal D21 in the case of diversity operation and not to output it in the case of non-diversity operation.

  The switch 29 receives the outputs of the receivers 22a and 22b, does not output in the case of diversity operation, and outputs the input signals as D22 and D23 in the case of non-diversity operation, respectively.

  The controller 27 determines whether or not the diversity operation is possible based on the detection results output from the level detectors 23a and 23b, and outputs control signals corresponding to the determination results to the switches 11, 28, and 29.

  With the above configuration, according to the present embodiment, when the controller 27 determines that the state of radio wave propagation (line quality) is good based on the received electric field detected by the level detectors 23a and 23b, diversity is achieved. A control signal for stopping the operation is sent to the switch 11 on the transmission side and the switches 28 and 29 on the reception side. When it is determined that the line quality is not good, a control signal for diversity operation is sent to the switch 11 on the transmission side and the switches 28 and 29 on the reception side.

  In this way, in this embodiment, the amount of data to be transmitted can be increased according to the situation of radio wave propagation. That is, when the radio wave propagation characteristics are good and the C / N is high, the diversity operation is stopped and the data amount is doubled by effectively using the frequency band. When the radio wave propagation characteristics deteriorate and the C / N ratio becomes low, the diversity operation is performed to improve the S / N ratio and maintain the line quality.

  In the above embodiment, the phase shifter 24 is inserted into the output of the receiver 22b. However, the same effect can be obtained by inserting it into the output of the receiver 22a.

  Further, the antennas 40 and 50 can be configured by a total of four surfaces including two antennas for transmission and two antennas for reception without using the combiner 13 and the duplexer 21. Furthermore, frequency diversity combining is also effective for a combining method of three or more waves. The synthesizer 26 can also be configured as a selective diversity by a switch.

  Next, another embodiment of the wireless communication system of the present invention will be described. FIG. 2 is a block diagram showing another example of the present embodiment.

  Referring to FIG. 2, it is different from FIG. 1 in that error rate detectors 31 and 32 are used instead of level detectors 23a and 23b for detecting the received power level.

  The error rate detector 31 receives the combined output output from the combiner 26, detects the error rate, and outputs it to the control unit 33.

  The error rate detector 32 receives the respective signals output from the receivers 22 a and 22 b, detects the respective error rates, and outputs them to the control unit 33.

  Error control for detecting the error rate can be appropriately selected from a parity check method, a count check method, a CRC (Cyclic Redundancy Check) method, a Hamming code method, and the like.

  Based on the information output from the error rate detectors 31 and 32, the control unit 33 determines whether or not the radio wave propagation status is good. If the control unit 33 determines that the radio wave propagation status is good, the control signal stops the diversity operation. Is sent to the switch 11 on the transmission side and the switches 28 and 29 on the reception side. If it is determined that the state of radio wave propagation is not good, diversity control, that is, the same data is transmitted in two systems on the transmission side, and the control signal for performing diversity combining is transmitted to the switch 11 and switch 28 on the reception side. To the switch 29.

  In this way, by determining whether the radio wave propagation status is good or not based on the error rate, it is possible to increase the transmission capacity when the line quality is good while ensuring the line quality more reliably.

  Further, in the embodiment described above, the radio wave propagation status can be calculated as a digital value, so that it is possible to easily integrate LSI or the like, such as being configured with a programmable device (FPGA or the like). And the device can be miniaturized.

It is a block diagram which shows schematic structure of the radio | wireless communications system of embodiment of this invention. It is a block diagram which shows the other Example of this Embodiment.

Explanation of symbols

11 switch 12a, 12b transmitter 13 combiner 21 duplexer 22a, 22b receiver 23a, 23b level detector 24 phase shifter 25 phase detector 26 combiner 27, 33 control unit 28, 29 switch 31, 32 error rate Detector 40, 50 Antenna

Claims (7)

A wireless communication apparatus having an antenna and a plurality of transmission / reception means and a control unit for determining line quality, and when the control unit determines that the line quality is good from the state of radio wave propagation, The switching operation of the own device and the opposite device is controlled so that different data is transmitted / received by the plurality of transmission / reception means, and when the line quality is judged unsatisfactory, the switching operation for diversity transmission / reception is controlled. A wireless communication device. The wireless communication apparatus according to claim 1, wherein the control unit controls a switching operation based on each signal level received by the plurality of transmission / reception means. The radio communication apparatus according to claim 1, wherein the control unit controls a switching operation based on an error rate of an individual signal or a combined signal received by the plurality of transmission / reception units. In a wireless communication method of a wireless communication apparatus having a plurality of transmission / reception functions capable of transmitting / receiving simultaneously, wireless control is performed to perform switching control between transmission / reception of the same signal or transmission / reception of different signals depending on radio wave propagation conditions Communication method. 5. The wireless communication apparatus according to claim 4, wherein the switching control controls a switching operation based on respective signal levels received by the plurality of transmission / reception means. 5. The wireless communication method according to claim 4, wherein the switching control controls a switching operation based on an error rate of individual signals or combined signals received by the plurality of transmission / reception means. A radio communication system comprising: a radio communication device that is opposed to the radio communication method according to any one of claims 4 to 6.

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