JP2009016921A - Diversity receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a diversity receiver of high receiving quality. <P>SOLUTION: First main waves x1-x4 from receivers 11-14 are inputted to a second main wave generation means 20 to generate second main waves y1-y4 of delay main components. The first main wave and the second main wave are inputted to band split means 31 and 32, and are divided into low, middle and high bands before input to a signal converting section 40. In the signal converting section 40, the main waves are rearranged to a set of x1, x2, y3, y4 and a set of x3, x4, y1, y2 in each band. They are synthesized for every set to generate first and second synthetic signals. Three first synthetic signals for respective bands are synthesized by a synthesizer 61 and three second thynthetic signals for respective bands are synthesized by a synthesizer 62. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a diversity receiver useful for mobile communication and the like provided with a plurality of antennas.

  As diversity receivers useful for mobile communication and the like, those described in Patent Documents 1 to 4, for example, are known.

  Patent Documents 1 and 2 disclose diversity receivers that can ensure high reception quality by separating a signal mainly composed of a delayed wave from a received signal. In Patent Documents 1 and 2, a plurality of reception signals received by a plurality of antennas are combined, and the combined signal is subtracted from each reception signal to generate a signal having a delayed wave as a main component.

  Patent Document 3 discloses a diversity receiver that divides a received signal into a plurality of frequency bands, weights and synthesizes the received signals divided for each frequency band, and combines the combined signals for each frequency band. Has been. Since the signal level for each frequency band is leveled, according to the diversity receiver according to Patent Document 3, the influence of frequency selective fading due to multipath is reduced, and the reception quality is improved.

Patent Document 4 shows that when a diversity receiver is mounted on a vehicle, the communication quality can be improved by switching the combination for synthesizing received signals according to the speed of the vehicle. Specifically, antennas are arranged at four locations on the left front, right front, left rear, and right rear of the vehicle, and when the vehicle speed is higher than a predetermined speed, a set of reception signals of the left front and right front antennas, If the vehicle's speed is slower than the predetermined speed, the left rear and right rear antennas receive signals, and the left front and left rear antennas receive signals. It is shown that the received signals are combined for each set.
JP2003-174391 JP 2004-120334 A JP2004-221808 JP 2006-261815 A

  According to Patent Document 1, it is possible to extract only a desired wave that arrives from a first direction with high received power with higher purity. According to Patent Document 2, the first wave extracted with the characteristic having directivity in the first direction and the second wave extracted with the characteristic not having directivity in the first direction are combined for each carrier. Therefore, delayed waves are also used. However, in both documents, there is only one type of signal that can be obtained, such as in mobile communications, where the direction of arrival of radio waves, the intensity ratio of desired and delayed waves, the delay time of delayed waves, etc. change frequently. In this case, high quality reception cannot be realized stably.

  According to Patent Document 3, the desired wave can be extracted with high accuracy even in an environment where the delay time of the delayed wave is long. However, since one type of signal is obtained, radio waves such as mobile communication can be obtained. In an environment where the direction of arrival and the intensity ratio between the desired wave and the delayed wave frequently change, it is not possible to realize high-quality reception stably.

  Further, according to Patent Document 4, since the antenna to be combined is switched according to the traveling speed of the moving body, higher quality reception is possible regardless of low speed traveling or high speed traveling. However, since only the maximum ratio combining or equal gain combining is performed to combine the signals of the respective antennas, only the incoming wave having the maximum power is extracted. Therefore, in an environment where the direction of arrival of radio waves, the intensity ratio of desired and delayed waves, the delay time of delayed waves, etc. change frequently, such as in mobile communications, it is stable only by switching the antenna to be combined. Thus, high quality reception cannot be realized.

  Therefore, in any of the above-described techniques, a reception state with high reception quality cannot be maintained for a long time when the radio wave environment changes rapidly such as in mobile communication.

  Accordingly, an object of the present invention is that the direction of the desired wave that arrives and the direction of the delayed wave thereof change frequently in time, and the power of those radio waves changes frequently in time. It is to be able to maintain high-quality communication even in a mobile communication environment.

  In a diversity receiver having N (N ≧ 2) antennas, the first invention is configured to obtain N second main waves mainly composed of delayed waves from the N first main waves received by each antenna. Second main wave generating means for generating, band dividing means for dividing each first main wave and each second main wave for each of a plurality of frequency bands, and for each divided frequency band, the first main wave and A signal conversion unit that combines a total of 2N signals combined with the second main wave into two sets, a first combining unit that weights and combines one of the two sets, and outputs a first combined signal; A second combining means for weighting and combining the other of the two sets and outputting a second combined signal; a first inter-band combining means for combining the first combined signal for each frequency band; and for each frequency band Having a second inter-band synthesizing unit for synthesizing the second synthesized signal. A diversity receiving apparatus according to claim.

  Further, the second invention is a diversity receiver having N (N ≧ 2) antennas, and N second main components each including a delayed wave as a main component from the N first main waves received by each antenna. A second main wave generating means for generating a wave, a signal conversion unit for combining a total of 2N signals including the first main wave and the second main wave into two sets, and each of the sets output from the signal conversion unit The first synthesized signal is obtained by weighting and synthesizing one of the two sets output from the band dividing means for each divided frequency band and the band dividing means for dividing the output into a plurality of frequency bands, respectively. Each of the divided frequency bands, a second combining unit that weights and combines the other of the two sets output by the band dividing unit, and outputs a second combined signal; First band for synthesizing the first synthesized signal for each frequency band And while synthesizing means, a diversity receiving apparatus, characterized in that a second band between synthesizing means for synthesizing the second combined signal for each frequency band.

  In the first and second inventions, the first main wave and the second main wave are generated at a stage before band division. In the first invention, after the band division, a combination of processing signals of each antenna system is determined for each divided frequency band and synthesized by maximum ratio synthesis or equal gain synthesis. In contrast, the second invention determines the combination of the processing signals of each antenna system before the band division. Then, band division is performed on the processed signals of the combined antenna systems, and synthesis is performed for each frequency band by maximum ratio synthesis, equal gain synthesis, or the like. In short, the positional relationship between the band dividing means and the signal converting unit is different between the first invention and the second invention.

  In both of the above inventions, the combination of dividing the total of 2N first and second main waves into two sets is arbitrary. It is not always necessary to divide into a set of N signals and a set of N signals, and it is not necessary to make the total of the signals of the two sets be 2N. For example, 8 may be selected from 16 signals, and the combination may be selected so that the 8 signals are divided into 5 groups and 3 groups. In the above description, the first main wave means a reception signal itself received by each antenna, and the second main wave means a delay wave of a desired wave. In the above invention, the first combined signal and the second combined signal can be obtained using the first main wave and the second main wave. These signals may be at least two signals, and three or more. It may be. That is, if a third main wave having a delay time different from that of the second main wave and having the second largest power after the second main wave is generated, the first, second, and third combined signals are generated using three signals. Can be obtained.

  According to a third invention, in the first invention or the second invention, the signal converter has a synthesis mode switching means for selecting one of the combinations divided into two groups and switching the combination. A diversity receiver characterized by the above.

  In a fourth invention according to any one of the first to third inventions, the second main wave generating means generates a composite wave by weighting and synthesizing the N first main waves. A diversity receiver that generates N second main waves by subtracting a composite wave component from one main wave.

  According to a fifth invention, in any one of the first to fourth inventions, the signal converters are combined such that each of the two sets includes at least both the first main wave and the second main wave. This is a diversity receiving apparatus.

  According to a sixth invention, in any one of the first to fifth inventions, the signal conversion unit includes a subtracter that subtracts each second main wave from each first main wave, and the signal output from the subtractor A diversity receiver characterized by combining a total of 2N signals including the second main wave into two sets.

  In a seventh aspect based on any one of the first aspect to the fifth aspect, the signal conversion unit includes a subtracter that subtracts each second main wave from each first main wave, and the signal output from the subtractor And a diversity receiving apparatus characterized by combining a total of 2N signals including the first main wave into two sets.

  According to an eighth invention, in any one of the first to seventh inventions, the diversity receiver is mounted on the moving body, and the N antennas are arranged forward and backward with respect to the traveling direction of the moving body. The signal conversion unit is a diversity receiver characterized by combining two sets of a signal set from an antenna arranged at the front and a set of signals from an antenna arranged at the rear.

In the first invention, after the second main wave is separated and generated from the first main wave, the first main wave and the second main wave are divided for each frequency band, and each antenna is divided for each divided frequency band. System processing signals are selected and combined, and at least two types of combined signals are obtained. Therefore, in a mobile communication environment in which the direction of the desired wave that arrives and the direction of the delayed wave each change frequently in time, and the power of those radio waves frequently changes in time. Can maintain high-quality communications.
In the second invention, after the second main wave is separated and generated from the first main wave, the processing signals of each antenna system are selected and divided into two groups, and then the signals of the antenna systems of each group are selected. On the other hand, after dividing for each frequency band, synthesis is performed for each frequency band. Therefore, as in the first invention, the direction of the desired wave that arrives and the direction of the delayed wave thereof change frequently in time, and the power of these radio waves changes frequently in time. Even in such a mobile communication environment, high-quality communication can be maintained. Furthermore, it is possible to realize a diversity receiver having high reception quality.

  Further, according to the third invention, the combination mode switching means selects and changes the optimum combination according to the environment to be used or the environment that fluctuates with time, and thus, stable and high reception for a long time. Quality can be ensured.

  According to the fourth invention, it is possible to separate and generate N second main waves whose main components are delay waves from the first main wave.

  According to the fifth aspect of the present invention, since the first synthesized signal and the second synthesized signal are output even if there is no delay wave and there is no second main wave output, the outputs of the first synthesized signal and the second synthesized signal are Stabilize.

  Further, according to the sixth and seventh inventions, the correlation between signals is lowered, that is, two waves arriving from different directions are extracted, and the first combination is performed by selectively combining those waves of each antenna system. Since the signal and the second combined signal are obtained, radio waves can be received in the mobile environment with higher reception quality.

  According to the eighth aspect of the invention, since the signals from the antennas arranged in the front and the signals from the antennas arranged in the rear are combined, the influence of the Doppler effect caused by the movement of the moving body is reduced. .

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a block diagram illustrating the configuration of the diversity receiver 1 according to the first embodiment. Diversity receiver 1 is roughly composed of two parts, a front end part A and a back end part B. Hereinafter, a specific description will be given with reference to FIG.

  The front end part A of the diversity receiver 1 includes antennas A1, A2, A3, A4, receivers 11, 12, 13, 14, second main wave generating means 20, band dividing means 31, 32, signal converting part 40, The synthesizers 51, 52, 53, 54, 55, 56, 61, 62 are configured. The second main wave generating means 20 includes a synthesizer 21 and a subtracter 22. The synthesizers 51, 52, and 53 correspond to the first synthesizer of the present invention, and the synthesizers 54, 55, and 56 correspond to the second synthesizer of the present invention. The synthesizer 61 corresponds to the first interband synthesizer of the present invention, and the synthesizer 62 corresponds to the second interband synthesizer of the present invention. The band dividing means 31 and 32 divide the input signal into three bands, a low band, a middle band, and a high band, and output them. The synthesizers 51 and 54 are used for synthesizing the low band, the synthesizers 52 and 55 are used for the middle band, and the synthesizers 53 and 56 are used for synthesizing the high band signal.

  The diversity receiver 1 is mounted on a vehicle, the antenna A1 is disposed on the right front side of the vehicle, the antenna A2 is disposed on the left front side of the vehicle, the antenna A3 is disposed on the right rear side of the vehicle, and the antenna A4 is disposed on the left rear side of the vehicle.

  Next, the operation of the diversity receiver 1 will be described. The signals received by the antennas A1 to A4 are down-converted, A / D converted, and quadrature demodulated by the receivers 11 to 14, respectively, and the first main waves x1, x2, x3 composed of I component and Q component, x4 is output, and the output is controlled by auto gain control. Each first main wave is a signal that has been received by each antenna, and is a signal having the highest power that is not extracted from a desired wave that has arrived from a specific direction. Thereafter, the first main waves x1 to x4 are input to the band dividing unit 31 and the second main wave generating unit 20.

  The second main wave generating means 20 generates the second main waves y1, y2, y3, y4 as follows. First, in the synthesizer 21, the input first main waves x1 to x4 of each antenna system are combined by weighting with a weighting coefficient to generate a combined wave. In the weighting synthesis, the weighting coefficient is determined so that the cross-correlation between the synthesized signal and the signal of each antenna system becomes high. Therefore, the directivity of this synthesized signal is controlled so as to extract a wave having the maximum power, that is, a desired wave is obtained. This combining method is a well-known method such as maximum ratio combining and equal gain combining. Next, the subtractor 22 generates the second main waves y1 to y4 by subtracting the composite wave component (the composite wave obtained by multiplying the composite wave by the complex conjugate of the weight coefficient) from the first main waves x1 to x4. Since the synthesized wave is mainly composed of the desired wave, the remaining delayed wave can be obtained by subtracting the desired wave from the received signal. Therefore, the second main wave is a signal whose main component is a delayed wave received by delaying the desired wave. The reason why the complex conjugate of the weight coefficient is used is to convert the combined signal into components of each antenna system corresponding to the combined signal. Thereafter, the second main waves y <b> 1 to y <b> 4 are input to the band dividing unit 32.

  The first main waves x1 to x4 input to the band dividing unit 31 and the second main waves y1 to y4 input to the band dividing unit 32 are respectively divided into three bands of low band, middle band, and high band. Is output.

  As described above, in the diversity receiver 1 of the present invention, after separating and generating the second main wave mainly composed of the delayed wave from the first main wave, the first and second main waves are separately divided into bands. is doing. Therefore, by separating and generating the second main wave, it is possible to draw out both the advantage that the delayed wave can be used as an information source and the advantage that the frequency fading resistance is improved by dividing and synthesizing the band. Therefore, the reception quality can be further improved in the mobile environment in which the arrival direction and power fluctuation are converted temporally.

  Hereinafter, signal processing in the signal converter 40 and the combiners 51 and 54 in the low band will be described with reference to FIG. The signal combinations of the low-band first main waves x1 to x4 and the second main waves y1 to y4 are changed in the signal conversion unit 40, and the combination of x1, x2, y3, and y4, and y1, y2, x3, and x4 Divided into groups. Then, x1, x2, y3, and y4 are input to the combiner 51, and y1, y2, x3, and x4 are input to the combiner 54. In the synthesizer 51, x1, x2, y3, and y4 are weighted with a weighting coefficient and synthesized, and a first synthesized signal is output. That is, the weighting factor is determined so that the cross-correlation between the first combined signal and each of the signals x1, x2, y3, and y4 becomes large. This method of determining the weighting factor is well known as maximum ratio combining, equal gain combining, and the like. In the synthesizer 54, the weights y1, y2, x3, and x4 are weighted by weighting coefficients and combined to output a second combined signal. That is, the weighting factor is determined so that the cross-correlation between the second combined signal and each of the signals y1, y2, x3, and x4 is increased. Hereinafter, a combination of a set of x1, x2, y3, and y4 and a set of y1, y2, x3, and x4 is referred to as a combination mode 1.

  In this synthesis mode 1, the first main waves x1 to x4 as shown in FIG. 3 are synthesized by the synthesizer 51, and the second main waves y1 to y4 are synthesized by the synthesizer 54 (hereinafter referred to as synthesis mode 0). There are the following advantages. In the synthesis mode 0, since the first main waves and the second main waves are combined with each other, the output of the second composite signal depends only on the second main wave, and the second main wave is output when there is no output of the second main wave. The synthesized signal is not generated and the output is not stable. On the other hand, in the synthesis mode 1, since the first main wave is input to both the combiners 51 and 54, the first and second synthesized signals are generated regardless of the presence or absence of the second main wave, and the output is stabilized. ing.

  Similarly, in the middle band and the high band, the first and second main waves are synthesized in the synthesis mode 1. In the middle band, the first and second combined signals are output from the combiners 52 and 55, and in the high band, the first and second combined signals are output from the combiners 53 and 56.

  The first synthesized signal of the three bands of low band, middle band and high band output from the combiners 51 to 53 is input to the combiner 61, and the three bands of low band, middle band and high band output from the combiners 54 to 56. The second synthesized signal is input to the synthesizer 62. The synthesizer 61 synthesizes and outputs the first synthesized signal of the three bands after phase matching between them, and the synthesizer 62 synthesizes and outputs the second synthesized signal of the three bands. Output signals from the synthesizers 61 and 62 are sent to the back-end unit B at the subsequent stage.

  The signal input to the back-end unit B is demodulated into a modulated signal of each carrier by a decoder 90 using FFT, is combined with each code, and then input to the video processing unit 91 and the audio processing unit 92, respectively. . The video processor 91 extracts the video signal, and the audio processor 92 extracts the audio signal, and the video data and audio data are output.

  The diversity receiving device 2 according to the second embodiment is obtained by replacing the signal converting unit 40 of the diversity receiving device 1 with a signal converting unit 41. Hereinafter, signal processing in the signal conversion unit 41 and the combiners 51 and 54 will be described with reference to FIG. The signal conversion unit 41 includes a subtractor 70. The subtractor 70 subtracts the second main waves y1 to y4 from the first main waves x1 to x4 to obtain signals z1 to z4 (zi = xi-yi, i = 1). ~ 4) is output. This output signal is a desired wave from the first arrival direction with high power as a result of removing the second main wave, which is a delayed wave, from the received signal. Therefore, the signals z1 to z4 correspond to the corrected first main wave. In the synthesizer 51, the signals z1 to z4 are weighted and synthesized, and a first synthesized signal is output. In the synthesizer 54, the second main waves y1 to y4 are weighted and synthesized, and a second synthesized signal is output. Hereinafter, the signal synthesis by the signal converter 41 and the combiners 51 and 54 is referred to as a synthesis mode 2.

  In the synthesis mode 2, the first synthesized signal is a desired wave having the maximum power, and the second synthesized signal is a delayed wave having the next highest power. That is, since the obtained first and second synthesized signals are obtained from radio waves propagated through different paths, the correlation between the two signals can be lowered, and in an environment where the arrival direction and the power of the incoming radio wave fluctuate with time. High quality reception state can be maintained for a long time. In this mode, the power of the desired wave arriving from the first direction and the delayed wave arriving from the second direction are approximately the same, and when these radio waves are received uniformly by each antenna, the power is Since two first and second combined signals of the same degree can be obtained, it is optimal for use in such an environment.

  The diversity receiving device 3 according to the third embodiment is obtained by replacing the signal converting unit 40 of the diversity receiving device 1 with a signal converting unit 42. Hereinafter, signal processing in the signal converter 42 and the combiners 51 and 54 will be described with reference to FIG. The signal conversion unit 42 includes a subtracter 71. In the subtractor 71, signals z1 to z4 (zi = xi-yi, i = 1) are obtained by subtracting the second main waves y1 to y4 from the first main waves x1 to x4. ~ 4) is output. These signals z1 to z4 become desired waves and become the corrected first main wave. Then, a combination of the signals z1, z2 and the second main wave y3, y4 and a combination of the signals z3, z4, the second main wave y1, y2 are combined, and z1, z2, y3, y4 are sent to the combiner 51, z3 , Z4, y1, and y2 are input to the combiner 54. In the combiner 51, z1, z2, y3, and y4 are weighted and combined, and a first combined signal is output. The synthesizer 54 weights and synthesizes z3, z4, y1, and y2, and outputs a second synthesized signal. Hereinafter, the synthesis of signals by this combination is referred to as synthesis mode 3.

  The synthesis mode 3 is a combination of the synthesis mode 1 and the synthesis mode 2, and has an advantage that the correlation between signals is low and the outputs of the first synthesized signal and the second synthesized signal are stable.

  Note that the inputs of the signals y1 and y2 to the combiner 54 may be switched to the combiner 51, and the inputs of the first combiner 51 of the signals y3 and y4 may be switched to the combiner 54 for input. In this case, for example, four signals of the first main waves x1 and x2 and the second main waves y1 and y2 from the antenna system installed in front of the vehicle are combined to obtain a first combined signal. . Further, the four signals of the first main waves x3 and x4 and the second main waves y3 and y4 by the antenna system installed at the rear of the vehicle are combined to obtain a second combined signal. This eliminates the Doppler effect because the synthesis by the desired wave and the delayed wave coming from the front of the vehicle and the synthesis by the desired wave and the delayed wave coming from the rear of the vehicle are executed independently. Highly reliable and stable reception is possible.

  The diversity receiving device 4 according to the fourth embodiment is obtained by replacing the signal converting unit 40 of the diversity receiving device 1 with a signal converting unit 43. Hereinafter, signal processing in the signal conversion unit 43 and the combiners 51 and 54 will be described with reference to FIG. In the signal converter 43, the first main waves x1 to x4 and the second main waves y1 to y4 are converted into a set of signals from an antenna disposed in front of the vehicle and signals from the antenna disposed in the rear of the vehicle. Combine with the pair. Here, x1 and y1 are signals from the antenna A1 arranged at the front right of the vehicle, x2 and y2 are signals from the antenna A2 arranged at the left front, x3 and y3 are signals from the antenna A3 arranged at the right rear, x4 and y4 are signals from the antenna A4 arranged at the rear left. Therefore, in the signal conversion unit 43, the combination of x1, x2, y1, and y2 and the combination of x3, x4, y3, and y4 are combined. x1, x2, y1, and y2 are input to the combiner 51, and x3, x4, y3, and y4 are input to the combiner 54. In the combiner 51, x1, x2, y1, and y2 are weighted and combined, and the first combined signal is output. In the synthesizer 54, x3, x4, y3, and y4 are weighted and synthesized, and a second synthesized signal is output. Hereinafter, the synthesis of signals by this combination is referred to as synthesis mode 4.

  In this combination mode 4, signals from antennas arranged in the front and signals from antennas arranged in the rear are synthesized. Therefore, the antenna installed in the front receives the radio wave coming from the front and the delayed wave, and the antenna arranged in the rear receives the radio wave coming from the rear and the delayed wave. Compared with the above, the influence of the Doppler effect caused by the movement of the vehicle is reduced.

  In the diversity receiving device 5 of the fifth embodiment, the signal converting unit 40 of the diversity receiving device 1 is replaced with a signal converting unit 44. Hereinafter, signal processing in the signal conversion unit 44 and the combiners 51 and 54 will be described with reference to FIG. The signal conversion unit 44 includes a subtractor 72. The subtractor 72 subtracts the second main waves y1 to y4 from the first main waves x1 to x4 to obtain signals z1 to z4 (zi = xi−yi, i = 1). ~ 4) is output. These signals z1 to z4 become desired waves and become the corrected first main wave. Then, the signals z1 to z4 are combined into a set of signals from the antenna arranged at the front and a set of signals from the antenna arranged at the rear, that is, a set of z1 and z2 and a set of z3 and z4. z1 and z2 are input to the combiner 51, and z3 and z4 are input to the combiner 54. In the synthesizer 51, z1 and z2 are weighted and synthesized, and a first synthesized signal is output. In the synthesizer 54, z3 and z4 are weighted and synthesized, and a second synthesized signal is output. Hereinafter, the synthesis of signals by this combination is referred to as synthesis mode 5.

  In the synthesis mode 5, since signals z1 to z4 obtained by subtracting the second main waves y1 to y4 from the first main waves x1 to x4 are used for synthesis, only the desired wave coming from the first direction is extracted, Synthesis with only the desired wave is possible. In addition, since the signals are combined by a set of z1 and z2 which are signals from the antenna arranged at the front and a set of z3 and z4 which are signals from the antenna which is arranged at the rear, the influence of the Doppler effect is reduced. The In this case, it is most suitable for communication of an object moving at high speed in an environment where the power of the desired wave is strong and the power of the delayed wave is weak.

  The diversity receiving device 6 of the sixth embodiment is obtained by replacing the signal converting unit 40 of the diversity receiving device 1 with a signal converting unit 45. Hereinafter, signal processing in the signal converter 45 and the combiners 51 and 54 will be described with reference to FIG. The signal conversion unit 45 includes a subtractor 73. The subtractor 73 subtracts the second main waves y1 to y4 from the first main waves x1 to x4 to obtain signals z1 to z4 (zi = xi−yi, i = 1). ~ 4) is output. Since this signal is obtained by subtracting the second main wave from the first main wave, the signal becomes a desired wave having a large power coming from the first direction. The signals z1 to z4 become the corrected first main wave. Then, the signals z1 to z4 and the second main waves y1 to y4 are divided into a set of signals from the antenna arranged at the front and a set of signals from the antenna arranged at the rear, that is, z1, z2, y1, y2 And a set of z3, z4, y3, and y4. z1, z2, y1, and y2 are input to the combiner 51, and z3, z4, y3, and y4 are input to the combiner 54. In the combiner 51, z1, z2, y1, and y2 are weighted and combined, and a first combined signal is output. In the synthesizer 54, z3, z4, y3, and y4 are weighted and synthesized, and a second synthesized signal is output. Hereinafter, the synthesis of signals by this combination is referred to as synthesis mode 6.

  This synthesis mode 6 is a combination of the synthesis mode 4 and the synthesis mode 5, and has the advantage that the influence of the Doppler effect caused by the movement of the vehicle is reduced and the correlation between signals can be lowered. It is. In the synthesis mode 5, only the signals z1 to z4 obtained by subtracting the second main waves y1 to y4 from the first main waves x1 to x4 are combined. In the synthesis mode 6, the second main waves y1 to y4 are also included. This mode is suitable for high-speed mobile communication in an environment where the power of the delayed wave is not weak.

  FIG. 9 is a block diagram illustrating a configuration of the diversity receiver 7 according to the seventh embodiment. The difference from the diversity receiver 1 is that the signal conversion unit 40 includes a synthesis mode switching unit 80. The synthesis mode switching means 80 can select one of the synthesis modes 0 to 6 and change the synthesis mode. The synthesis mode is automatically controlled and changed according to the environment. For example, when the vehicle speed is high, the mode automatically shifts to the synthesis mode 4 to reduce the influence of the Doppler effect. In the case of low-speed driving and urban driving, mode 3 or mode 1, the radio wave environment in the countryside on flat ground If it is good, control is performed as in mode 5 or the like. In this way, the diversity receiver 7 can ensure higher reception quality by selecting and changing the optimum combining mode in accordance with the environment.

In the present embodiment, as shown in FIG. 10, the signal converters 46 that select the signals of each antenna system and combine them into two sets have the first main waves x1, x2, x3, x4 of each antenna system, This is executed for the two main waves y1, y2, y3, and y4. Then, for each set of component signals, the band is divided by the band dividing means 31 and 32, and the cross-correlation with the synthesized signal is increased for each divided band by the combiner 51-56. Each set of component signals is synthesized. Then, the synthesizers 61 and 62 synthesize the synthesized signals for each band to obtain the first synthesized signal and the second synthesized signal.
In this embodiment, the position for performing the band division processing is different from that of the first to seventh embodiments. The present embodiment can be applied to each of the above embodiments 1-7.

  Instead of the second main wave generating means 20 in the first to eighth embodiments, a second main wave generating means 23 shown in FIG. 11 may be used. The second main wave generating means 23 includes synthesizers 24 and 25 and subtractors 26 and 27. In this second main wave generating means 23, x1 and x2 are synthesized by the synthesizer 24, x3 and x4 are synthesized by the synthesizer 25, and the subtracter 26 subtracts the synthesized wave output from the synthesizer 24 from x1 and x2. Thus, the second main waves y1 and y2 are generated, and the subtractor 27 generates the second main waves y1 and y2 by subtracting the combined wave output from the combiner 25 from x3 and x4. That is, for example, for the signals of the antenna group installed in front of the vehicle, the second main wave is obtained using only the signals received by those antennas, and the signal of the antenna group installed in the rear of the vehicle is obtained. Thus, the second main wave is obtained using only signals received by those antennas. Thereby, even in the case of a vehicle moving at high speed, the second main wave can be extracted with high accuracy. Therefore, when this method is also used, it is optimal for use in a mode in which the signal of the antenna system installed in front of the vehicle and the signal of the antenna system installed in the rear are processed in separate groups. is there.

  In the present invention, the first main wave means a signal that is received by each antenna, that is, a signal in which a desired wave and its delayed wave are mixed, and a second signal from the signal that has been received is second. It also means a desired wave from which the main wave is removed.

  The diversity receiving apparatus of the present invention can be applied to viewing such as terrestrial digital television broadcasting on a moving body such as a vehicle.

1 is a block diagram illustrating a configuration of a diversity receiving device according to Embodiment 1. FIG. The figure explaining the synthesis mode 1. FIG. The figure explaining the synthesis mode 0. The figure explaining the synthesis mode 2. FIG. The figure explaining the synthesis mode 3. FIG. The figure explaining the synthesis mode 4. FIG. The figure explaining the synthesis mode 5. FIG. The figure explaining the synthesis mode 6. FIG. FIG. 10 is a block diagram illustrating a configuration of a diversity receiving device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a diversity receiving device according to an eighth embodiment. The block diagram which showed the structure of the 2nd main wave production | generation means 23. FIG.

Explanation of symbols

A1, A2, A3, A4: Antennas 11, 12, 13, 14: Receiver 20: Second main wave generation means 31, 32: Band division means 40, 41, 42, 43, 44, 45: Signal conversion section 51 52, 53, 54, 55, 56, 61, 62: Synthesizer 80: Synthesis mode switching means

Claims (8)

In a diversity receiver having N (N ≧ 2) antennas,
Second main wave generating means for generating N second main waves mainly composed of delayed waves from the N first main waves received by the antennas;
Band dividing means for dividing each first main wave and each second main wave into a plurality of frequency bands;
For each of the divided frequency bands, a signal conversion unit that combines a total of 2N signals including the first main wave and the second main wave into two sets;
First combining means for weighting and combining one of the two sets and outputting a first combined signal;
Second combining means for weighting and combining the other of the two sets and outputting a second combined signal;
First interband synthesizing means for synthesizing the first synthesized signal for each frequency band;
Second interband combining means for combining the second combined signal for each frequency band;
A diversity receiver characterized by comprising: In a diversity receiver having N (N ≧ 2) antennas,
Second main wave generating means for generating N second main waves mainly composed of delayed waves from the N first main waves received by the antennas;
A signal converter for combining a total of 2N signals including the first main wave and the second main wave into two sets;
Band division means for dividing each output of each set output by the signal conversion unit for each of a plurality of frequency bands;
For each of the divided frequency bands, first combining means for weighting and combining one of the two sets output by the band dividing means and outputting a first combined signal;
For each of the divided frequency bands, second combining means for weighting and combining the other of the two sets output by the band dividing means and outputting a second combined signal;
First interband synthesizing means for synthesizing the first synthesized signal for each frequency band;
Second interband combining means for combining the second combined signal for each frequency band;
A diversity receiver characterized by comprising:   3. The diversity reception according to claim 1, wherein the signal conversion unit includes a combination mode switching unit that selects one of the combinations divided into two groups and switches the combination. 4. apparatus.   The second main wave generating means generates a composite wave by weighting and synthesizing the N first main waves, and subtracting the composite wave component from each of the first main waves to thereby generate the N first main waves. The diversity receiver according to any one of claims 1 to 3, wherein two main waves are generated.   5. The signal conversion unit according to claim 1, wherein each of the two pairs is combined so that each of the two sets includes at least both of the first main wave and the second main wave. Diversity receiver.   The signal conversion unit includes a subtracter that subtracts each second main wave from each first main wave, and outputs a signal output from the subtractor and a total of 2N signals including the second main wave, The diversity receiver according to claim 1, wherein the diversity receiver is combined into a set.   The signal conversion unit includes a subtracter that subtracts each second main wave from each first main wave, and outputs a signal output from the subtractor and a total of 2N signals including the first main wave, The diversity receiver according to claim 1, wherein the diversity receiver is combined into a set. The diversity receiver is mounted on a mobile object,
The N antennas are arranged forward and backward with respect to the moving direction of the moving body,
The signal conversion unit is combined into two sets, a set of signals from the antenna arranged in the front and a set of signals from the antenna arranged in the rear.
The diversity receiver according to any one of claims 1 to 7, wherein:

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