JP2010062603A - Wireless receiver - Google Patents

Abstract

A radio receiving apparatus capable of effectively suppressing interference wave power from another adjacent system is provided.
A radio receiving apparatus in which a use frequency band of another system is adjacent to one end or both ends of a channel band of a desired signal via a guard band, and includes a plurality of antenna elements 1 and the plurality of antenna elements 1 A weighted adder (weight multiplier 7 and adder 8) for weighting and adding signals based on the received signals, and a signal detecting unit for detecting signals in the band of the guard band from the received signals of the plurality of antenna elements 1 (High band side guard band signal extraction unit 3, low band side guard band signal extraction unit 4) and weight control unit 6 for controlling the weight of the weight addition unit according to the signal detected by the signal detection unit A wireless receiving device.
[Selection] Figure 3

Description

  The present invention relates to a radio reception apparatus that receives and combines signals using a plurality of antenna elements.

  The ITS (Intelligent Transport Systems) inter-vehicle communication system scheduled to start service in 2012 is expected to notify other vehicles of the position and speed information of the vehicle that is out of sight as one of its applications. It is considered to prevent encounter vehicle collision accidents at bad intersections, etc., and the 720 MHz band will be used. As shown in FIG. 1, the use frequency band of the digital terrestrial television broadcasting system is adjacent to the end of the use frequency band low frequency side of the ITS inter-vehicle communication system with the guard band of 5 MHz interposed therebetween. A frequency band used for electrical communication is adjacent to the end of the system on the high frequency side with a guard band of 5 MHz.

  As described above, since the frequency bands of other systems are adjacent to each other with the guard band sandwiched between both ends of the frequency band of the ITS inter-vehicle communication system, the ITS inter-vehicle communication system is affected by interference waves received from other adjacent systems. There is a concern that the reception performance of the inter-vehicle communication system deteriorates. Conventionally, AAA (adaptive array antenna) technology has been effective for suppressing interference waves.

In AAA (adaptive array antenna) technology, weights are determined using a MMSE (least square error method) algorithm (see Non-Patent Document 1) as a weight determination algorithm. Specifically, the weight is determined so that the evaluation function J ₀ that is the expected value of the square of the error signal is minimized.
J ₀ = E | r (n) −w ^H Z (n) | ²

  Here, r (n) represents a known signal as a reference signal, and Z (n) = [Z1 (n),..., ZM (n)] represents the nth sample in each antenna of the time waveform of the received signal. ,..., ZM (n) in the vector format, the reception amplitude of the nth sample at each antenna of the signal vector is represented, and w represents the weight vector to be obtained.

  To further strongly suppress paths with different Doppler frequencies, Patent Document 1 employs AAA (adaptive array antenna) technology in multicarrier transmission to monitor virtual subcarriers that are not used for transmission. There has been proposed a radio receiving apparatus that determines a combination weighting coefficient for each array antenna.

JP 2002-271240 A Nobuyoshi Kikuma, “Adaptive Antenna Technology”, 1st Edition, Ohm Co., Ltd., October 10, 2003, p. 35-37 Nobuyoshi Kikuma, “Adaptive Antenna Technology”, 1st Edition, Ohm Co., Ltd., October 10, 2003, p. 85-90 Shuichi Sasaoka, “Mobile Communications”, 1st edition, Ohm Co., Ltd., May 25, 1998, p. 291-293

  However, since the wireless receiver proposed in Patent Document 1 controls the weight so that the combined signal level of signals called virtual subcarriers in the use frequency band of the wireless receiver approaches 0, It is not possible to effectively suppress the interference wave power from another system whose use frequency band is adjacent to the use frequency band of the wireless reception device. In addition, the wireless receiving device proposed in Patent Document 1 is capable of controlling the weights only after the synchronization processing for synchronizing the desired signals of the respective antenna systems is completed and further converted into the frequency domain. Therefore, the wireless reception device proposed in Patent Document 1 is in a poor environment where the interference wave power from another system whose use frequency band is adjacent to the use frequency band of the wireless reception device is large and synchronization processing cannot be performed. Therefore, the interference wave cannot be effectively suppressed.

  In the above, the problems in the ITS inter-vehicle communication system have been described. However, a wireless system other than the ITS inter-vehicle communication system in which the use frequency band of another system is adjacent to both ends of the use frequency band or one end of the use frequency band. As in the case of the ITS inter-vehicle communication system, even in a wireless system in which the use frequency band of another system is adjacent to each other, it is possible to effectively suppress the interference wave received from the other system adjacent to the wireless system. This is an important issue in the wireless system.

  In view of the above situation, an object of the present invention is to provide a wireless reception device and a wireless reception method that can effectively suppress interference wave power from other adjacent systems.

  In order to achieve the above object, a radio receiving apparatus according to the present invention is a radio receiving apparatus in which a use frequency band of another system is adjacent to one or both ends of a channel band of a desired signal via a guard band. Antenna elements, a weighted adder for weighting and adding signals based on the received signals of the plurality of antenna elements, a signal in the guard band from the received signals of the plurality of antenna elements, and use of the other system A signal detection unit that detects at least one of the signals in the frequency band and a weight control unit that controls the weighting of the weighting addition unit according to the signal detected by the signal detection unit.

  Further, the weight control unit may control the weighting of the weighting addition unit so that the power of the signal detected by the signal detection unit is minimized.

  Further, the weight control unit controls weighting of the weighting addition unit so that a square error between a component corresponding to a known signal included in reception signals of the plurality of antenna elements and a reference signal is minimized. May be.

  Further, until the synchronization processing for synchronizing desired signals included in the reception signals of the plurality of antenna elements is completed, the weight control unit is configured so that the power of the signal detected by the signal detection unit is minimized. After controlling the weighting of the weighting addition unit and completing the synchronization process, the weight control unit has a square error between a component corresponding to a known signal included in the reception signals of the plurality of antenna elements and a reference signal. You may make it control the weight of the said weight addition part so that it may become the minimum.

  A desired signal extraction unit configured to extract the desired signal for each antenna system from reception signals of the plurality of antenna elements, wherein the weighting addition unit extracts the desired signal for each antenna system extracted by the desired signal extraction unit; May be output after weighted addition.

  In order to achieve the above object, a radio reception method according to the present invention is a radio reception method in which a frequency band of another system is adjacent to one or both ends of a channel band of a desired signal via a guard band. A weighted addition step of weighting and adding signals based on the reception signals of the plurality of antenna elements, and outputting the signals of the guard band band and the signals of the use frequency band of the other system from the reception signals of the plurality of antenna elements A signal detection step of detecting at least one; and a weight control step of controlling weighting in the weighting addition step in accordance with the signal detected in the signal detection step.

  In the weight control step, the weighting in the weighting addition step may be controlled so that the power of the signal detected in the signal detection step is minimized.

  In the weight control step, the weighting in the weighting and adding step is controlled so that a square error between the component corresponding to the known signal included in the received signals of the plurality of antenna elements and the reference signal is minimized. May be.

  Further, in the weight control step, the power of the signal detected in the signal detection step is minimized until synchronization processing for synchronizing desired signals included in the reception signals of the plurality of antenna elements is completed. After controlling the weighting in the weighting addition step and completing the synchronization process, in the weight control step, there is a square error between the component corresponding to the known signal included in the reception signals of the plurality of antenna elements and the reference signal. You may make it control the weight in the said weighting addition step so that it may become the minimum.

  In addition, a desired signal extraction step for extracting the desired signal for each antenna system from reception signals of the plurality of antenna elements is provided, and in the weighted addition step, the desired signal for each antenna system extracted in the desired signal extraction step May be output after weighted addition.

  According to the present invention, since the signal power in the guard band different from the frequency band of the desired signal and / or the signal power of the other system is detected, even if the synchronization processing is not performed on the desired signal, AAA (adaptive (Array antenna) directivity control becomes possible. Therefore, even in a poor reception environment in which synchronization processing cannot be performed due to the influence of interference wave power, nulls are directed to the interference wave by the directivity control of AAA (adaptive array antenna), and interference from other adjacent systems Wave power can be effectively suppressed.

  Embodiments of the present invention will be described below with reference to the drawings. Here, as an example of an ITS vehicle, an in-vehicle wireless reception device used in an ITS inter-vehicle communication system will be described as a wireless reception device according to the present invention. The in-vehicle wireless reception device 100 is installed in the vehicle 200 as shown in FIG. 2 and receives reception data of inter-vehicle communication used in the ITS inter-vehicle communication system.

<First embodiment>
FIG. 3 shows a schematic configuration of the in-vehicle wireless receiver according to the first embodiment of the present invention. The in-vehicle wireless reception apparatus shown in FIG. 3 includes M (M is a natural number of 2 or more) antennas 1, M desired signal extraction units 2, M high band guard band signal extraction units 3, and M The low-band guard band signal extraction units 4, 3M A / D converters 5, weight control units 6, M weight multipliers 7, and adders 8 are provided.

  Each antenna 1 receives a high frequency signal. Each desired signal extraction unit 2 extracts only a desired signal, that is, a signal in the occupied frequency band of the ITS inter-vehicle communication system. Each desired signal extraction unit 2 can be realized by, for example, a bandpass filter.

  Each high band side guard band signal extraction part 3 extracts only the signal of the guard band band (725 MHz-730 MHz) adjacent to the high band side of the use frequency band (715 MHz-725 MHz) of the ITS inter-vehicle communication system. Each low band side guard band signal extraction part 4 extracts only the signal of the guard band band (710 MHz-715 MHz) adjacent to the low band side of the use frequency band (715 MHz-725 MHz) of the ITS inter-vehicle communication system. Each high band guard band signal extraction unit 3 and each low band guard band signal extraction unit 4 can be realized by, for example, a band pass filter.

  The guard band is a band where the signal power is essentially zero. However, when the interference wave power from other systems whose use frequency band is adjacent to the use frequency band of the ITS inter-vehicle communication system increases and the desired signal is deteriorated, the signal power of the guard band band does not become zero. It is possible. FIG. 4 shows an example of an image diagram when the signal extracted by each high band side guard band signal extraction unit 3 is viewed on the frequency axis when the signal power of the guard band does not become zero. FIG. 5 shows an example of an image diagram when the signal extracted by the band guard band signal extraction unit 4 is viewed on the frequency axis. The guard band signal extracted by the high band guard band signal extraction unit 3 and the low band guard band signal extraction unit 4 is a signal in a part of the guard band band even if the signal is in the entire guard band band. It may be.

  Each A / D converter 5 converts each analog signal extracted by each desired signal extraction unit 2, each high band side guard band signal extraction unit 3, and each low band side guard band signal extraction unit 4 into a digital signal. Convert.

  The weight control unit 6 performs A / D conversion on the high band side guard band signal extracted by each high band side guard band signal extraction unit 3 and the low band side guard band signal extraction unit 4 extracts it. A signal obtained by A / D-converting the low band side guard band signal is input, and the weight for each antenna system is determined so as to minimize the signal of the guard band adjacent to the use frequency band of the ITS inter-vehicle communication system.

Here, the guard band signal vector obtained from the system of the high band side guard band signal extraction unit 3 is X, the guard band signal vector obtained from the system of the low band side guard band signal extraction unit 4 is Y, and the weight vector to be obtained Is set to w, the weight controller 6 uses the power inversion adaptive array (PIAA) (see Non-Patent Documents 2 and 3) to determine the weight so that the following evaluation function J ₁ is minimized.
J ₁ = E [α | 0−w ^H X | ² + β | 0−w ^H Y | ² ]

Α and β are constants. For example, when α = 1 and β = 0, the expectation of the square of the signal of the guard band band (725 MHz to 730 MHz) adjacent to the high frequency side of the use frequency band (715 MHz to 725 MHz) of the ITS inter-vehicle communication system The weight is determined so that the evaluation function J _{1 as} a value is minimized, and the signal power of the guard band band (725 MHz to 730 MHz) adjacent to the high frequency side of the use frequency band (715 MHz to 725 MHz) of the ITS inter-vehicle communication system Is minimized.

  Each weight multiplier 7 multiplies the digitally converted desired signal and the weight for each antenna system output from the weight control unit 6. The adder 8 adds and combines the outputs of the weight multipliers 7.

  Since the in-vehicle wireless receiver shown in FIG. 3 detects signal power in a guard band that is different from the frequency band of the desired signal, AAA (adaptive array antenna) can be used even if synchronization processing is not performed on the desired signal. ) Directivity control is possible. Therefore, even in a poor reception environment in which synchronization processing cannot be performed due to the influence of interference wave power, nulls are directed to the interference wave by AAA (adaptive array antenna) directivity control, and the frequency band used across the guard band However, it is possible to effectively suppress the interference wave power from other systems adjacent to the use frequency band of the ITS inter-vehicle communication system.

<Second embodiment>
FIG. 6 shows a schematic configuration of a radio reception apparatus according to the second embodiment of the present invention. In FIG. 6, the same parts as those in FIG. The in-vehicle wireless reception device shown in FIG. 6 includes M (M is a natural number of 2 or more) antennas 1, M desired signal extraction units 2, M high band side guard band signals and other system signal extraction units. 13, M low band side guard band signal / other system signal extraction units 14, 3M A / D converters 5, weight control units 6, M weight multipliers 7, and adders 8. And.

  Each antenna 1 receives a high frequency signal. Each desired signal extraction unit 2 extracts only a desired signal, that is, a signal in the occupied frequency band of the ITS inter-vehicle communication system. Each desired signal extraction unit 2 can be realized by, for example, a bandpass filter.

  Each high band side guard band signal / other system signal extraction unit 13 includes a guard band band (725 MHz to 730 MHz) signal adjacent to the high band side of the use frequency band (715 MHz to 725 MHz) of the ITS inter-vehicle communication system, and a guard. Only the signal of the other system adjacent to the high frequency side end of the use frequency band of the ITS inter-vehicle communication system is extracted through the band band (725 MHz to 730 MHz). Each high band side guard band signal / other system signal extraction unit 13 can be realized by, for example, a band pass filter.

  Each low band side guard band signal / other system signal extraction unit 14 includes a guard band band (710 MHz to 715 MHz) signal adjacent to the low band side of the use frequency band (715 MHz to 725 MHz) of the ITS inter-vehicle communication system, and a guard. Only the signals of other systems that are adjacent to the lower end of the use frequency band of the ITS inter-vehicle communication system are extracted via the band band (710 MHz to 715 MHz). Each low band side guard band signal / other system signal extraction unit 14 can be realized by, for example, a band pass filter.

  The guard band is a band where the signal power is essentially zero. However, when the interference wave power from other systems whose use frequency band is adjacent to the use frequency band of the ITS inter-vehicle communication system increases and the desired signal is deteriorated, the signal power of the guard band band does not become zero. It is possible. FIG. 7 shows an example of an image diagram when the signal extracted by each high band side guard band signal / other system signal extraction unit 13 is viewed on the frequency axis when the signal power of the guard band is not zero. FIG. 8 shows an example of an image diagram when the signal extracted by each low band side guard band signal / other system signal extraction unit 14 is viewed on the frequency axis. The guard band signal extracted by the high band guard band signal / other system signal extractor 13 and the low band guard band signal / other system signal extractor 14 may be a signal in the entire guard band band, It may be a signal that is part of the guard band. Further, the signals of other systems extracted by the high band side guard band signal / other system signal extraction unit 13 and the low band side guard band signal / other system signal extraction unit 14 are signals in the entire use frequency band of the other system. Alternatively, the signal may be a part of a frequency band used by another system.

Here, the guard band signal / other system signal vector obtained from the system of the high band side guard band signal / other system signal extraction unit 13 is X ′, and from the system of the low band side guard band signal / other system signal extraction unit 14. When the obtained guard band signal / other system signal vector is Y ′ and the obtained weight vector is w, the weight controller 6 determines the weight so that the following evaluation function J ₂ is minimized. Α and β are constants.
J ₂ = E [α | 0−w ^H X ′ | ² + β | 0−w ^H Y ′ | ² ]

  Each weight multiplier 7 multiplies the digitally converted desired signal and the weight for each antenna system output from the weight control unit 6. The adder 8 adds and combines the outputs of the weight multipliers 7.

  Since the in-vehicle wireless reception device shown in FIG. 6 detects signal power in a guard band band different from the frequency band of the desired signal, similarly to the in-vehicle wireless reception device shown in FIG. 3, synchronization processing is performed on the desired signal. Even if it is not done, directivity control of AAA (adaptive array antenna) becomes possible. Therefore, even in a poor reception environment in which synchronization processing cannot be performed due to the influence of interference wave power, nulls are directed to the interference wave by AAA (adaptive array antenna) directivity control, and the frequency band used across the guard band However, it is possible to effectively suppress the interference wave power from other systems adjacent to the use frequency band of the ITS inter-vehicle communication system.

  6 differs from the in-vehicle radio receiver shown in FIG. 3 in that the frequency used is not only the signal in the guard band but also the frequency used in the ITS inter-vehicle communication system via the guard band. Since the weight is controlled based on the signals of other systems adjacent to the end of the ITS, interference occurs when the power of the desired signal in the use frequency band of the ITS inter-vehicle communication system leaks to the guard band. A state of being suppressed as a wave can be avoided, and the possibility of reception being impossible can be reduced.

<Third embodiment>
FIG. 9 shows a schematic configuration of a wireless reception apparatus according to the third embodiment of the present invention. In FIG. 9, the same parts as those in FIG. The on-vehicle wireless reception device shown in FIG. 9 includes M (M is a natural number of 2 or more) antennas 1, M desired signal extraction units 2, M high frequency side other system signal extraction units 23, M Low-frequency side other system signal extraction units 24, 3M A / D converters 5, a weight control unit 6, M weight multipliers 7, and an adder 8.

  Each antenna 1 receives a high frequency signal. Each desired signal extraction unit 2 extracts only a desired signal, that is, a signal in the occupied frequency band of the ITS inter-vehicle communication system. Each desired signal extraction unit 2 can be realized by, for example, a bandpass filter.

  Each high-frequency side other system signal extraction unit 23 uses only the signals of other systems adjacent to the high-frequency side end of the usage frequency band of the ITS inter-vehicle communication system via the guard band (725 MHz to 730 MHz). To extract. Each high frequency side other system signal extraction part 23 is realizable by a band pass filter, for example.

  Each low-frequency side other system signal extraction unit 24 uses only the signals of other systems adjacent to the low-frequency side end of the usage frequency band of the ITS inter-vehicle communication system via the guard band (710 MHz to 715 MHz). To extract. Each low frequency side other system signal extraction part 24 is realizable by a band pass filter, for example.

  FIG. 10 shows an example of an image when the signal extracted by each high frequency side other system signal extraction unit 23 is seen on the frequency axis, and the signal extracted by each low frequency side other system signal extraction unit 24 is shown on the frequency axis. FIG. 11 shows an example of an image diagram when seen in FIG. Note that the signals of the other systems extracted by the high frequency side other system signal extraction unit 23 and the low frequency side other system signal extraction unit 24 may be signals in the other system use frequency bands even if they are signals in the entire use frequency band of other systems. May be a part of the signal.

Here, the other system signal vector obtained from the system of the high frequency side other system signal extraction unit 23 is set as X ", and the other system signal vector obtained from the system of the low frequency side other system signal extraction unit 24 is set as Y". When the weight vector is w, the weight controller 6 determines the weight so that the following evaluation function J ₃ is minimized. Α and β are constants.
J ₃ = E [α | 0−w ^H X ″ | ² + β | 0−w ^H Y ″ | ² ]

  Each weight multiplier 7 multiplies the digitally converted desired signal and the weight for each antenna system output from the weight control unit 6. The adder 8 adds and combines the outputs of the weight multipliers 7.

  Since the in-vehicle wireless receiver shown in FIG. 9 detects the signal power of another system different from the frequency band of the desired signal, AAA (adaptive array antenna) can be used even if the synchronization processing is not performed on the desired signal. Directivity control is possible. Therefore, even in a poor reception environment in which synchronization processing cannot be performed due to the influence of interference wave power, nulls are directed to the interference wave by AAA (adaptive array antenna) directivity control, and the frequency band used across the guard band However, it is possible to effectively suppress the interference wave power from other systems adjacent to the use frequency band of the ITS inter-vehicle communication system.

  In addition, the in-vehicle wireless reception device shown in FIG. 9 controls the weight based on the signal of another system whose use frequency band is adjacent to the end of the use frequency band of the ITS inter-vehicle communication system across the guard band. As a result, it is possible to avoid a state where the power of the desired signal in the use frequency band of the ITS inter-vehicle communication system is suppressed as an interference wave when leaking up to the guard band, and reception may be impossible. Can be reduced.

<Fourth embodiment>
FIG. 12 shows a schematic configuration of the in-vehicle wireless reception device according to the fourth embodiment of the present invention. In FIG. 12, the same parts as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. The in-vehicle wireless reception device shown in FIG. 12 has a configuration in which the weight control unit 6 of the in-vehicle wireless reception device shown in FIG. 3 is replaced with a weight control unit 16 and the output of the adder 8 is supplied to the weight control unit 16. It is.

Here, the guard band signal vector obtained from the system of the high band side guard band signal extraction unit 3 is X, the guard band signal vector obtained from the system of the low band side guard band signal extraction unit 4 is Y, and the weight vector to be obtained Is set to w, r (n) is a known signal as a reference signal, and Z (n) = [Z1 (n),..., ZM (n)] is received at the nth sample at each antenna of the time waveform of the received signal. amplitude Z1 (n), ..., when the received amplitude of the n-th sample of each antenna signal vector representing ZM (n) is in vector form, the weight control section 16, so that the following evaluation function J ₄ is minimized The weight is determined. The weight controller 16 generates a known signal r (n).
J ₄ = E [α | 0−w ^H X | ²
+ Β | 0−w ^H Y (n) | ²
+ Γ | r (n) −w ^H Z (n) | ² ]

α, β, and γ are constants, and when α = 0, β = 0, and γ = 1, the evaluation function J ₄ used by the weight control unit 16 is a conventional MMSE (least square error method). This is substantially the same as the evaluation function J ₀ used in the algorithm.

  For example, until the in-vehicle wireless reception device shown in FIG. 12 completes the synchronization process, γ = 0, α, and β are arbitrary values, and the used frequency band is the used frequency band of the ITS inter-vehicle communication system across the guard band. After suppressing the interference wave power from other systems adjacent to the in-vehicle wireless receiver shown in FIG. 12 and completing the synchronization process, α = 0, β = 0, and γ = 1. As described above, the values of the constants α, β, and γ can be changed.

  As a result, signal power in a guard band different from the frequency band of the desired signal is detected until the synchronization processing is completed, so even in a poor reception environment where synchronization processing cannot be performed due to the influence of interference wave power. The interference wave power from other systems adjacent to the use frequency band of the ITS inter-vehicle communication system with the guard band in between is directed toward the interference wave by the AAA (adaptive array antenna) directivity control. Can be effectively suppressed, and the establishment of synchronization can be improved. After the synchronization processing is completed, the directivity control of AAA (adaptive array antenna) can be performed by the conventional MMSE (least square error method) algorithm.

<Fifth embodiment>
FIG. 13 shows a schematic configuration of a wireless reception apparatus according to the fifth embodiment of the present invention. In FIG. 13, the same parts as those in FIG. 13 replaces the high band guard band signal extraction unit 3 and the low band guard band signal extraction unit 4 of the vehicle wireless reception apparatus shown in FIG. As a result, the A / D converter installed after the high band side guard band signal extraction unit 3 and the A / D converter installed after the low band side guard band signal extraction unit 4 are integrated. It is a configuration.

  The gain characteristic G33 of each desired signal removal unit 33 is shown in FIG. Each desired signal removing unit 33 removes only the desired signal, that is, the signal in the occupied frequency band of the ITS inter-vehicle communication system, and passes other signals. Each desired signal removal unit 33 can be realized by a band elimination filter, for example.

Here, when the signal vector obtained from the system of the desired signal removing unit 33 is Q and the weight vector to be obtained is w, the weight is determined so that the following evaluation function J ₅ is minimized in the weight control unit 6. .
J ₅ = E | 0−w ^H Q | ²

  The in-vehicle wireless receiving device according to the fifth embodiment of the present invention shown in FIG. 13 has a frequency band of use of the ITS inter-vehicle communication system as compared with the in-vehicle wireless receiving device according to the first embodiment of the present invention shown in FIG. Since weight control is performed to detect and suppress signals from other systems adjacent to the frequency band (signals that cause interference waves) over a wide range, the power of the desired signal in the frequency band used by the ITS inter-vehicle communication system is guarded. A state of being suppressed as an interference wave when leaking up to a band can be avoided, and the possibility of reception failure can be reduced.

<Modification of Fifth Embodiment>
A modification of the fifth embodiment of the present invention is shown in FIG. In FIG. 15, the same parts as those in FIG. The in-vehicle wireless reception device shown in FIG. 15 has a configuration in which the desired signal removal unit 33 of the in-vehicle wireless reception device shown in FIG.

  FIG. 16 shows the gain characteristics G43 of each desired signal / high band side signal removing unit 43. As shown in FIG. Each desired signal / high band side signal removal unit 43 includes a desired signal, a high band guard band signal, and a signal of another system adjacent to the high band side end of the use frequency band of the ITS inter-vehicle communication system. Remove everything. Each desired signal / high band side signal removal unit 43 can be realized by, for example, a low-pass filter.

Here, when the signal vector obtained from the system of the desired signal / high band side signal removal unit 43 is Q ′ and the weight vector to be obtained is w, the weight control unit 6 minimizes the following evaluation function J _6. The weight is determined.
J ₆ = E | 0−w ^H Q ′ | ²

  According to the configuration shown in FIG. 15, for example, the use frequency band of the ITS inter-vehicle communication system is higher than the interference wave from another system adjacent to the high frequency side of the use frequency band of the ITS inter-vehicle communication system. When interference waves from other systems adjacent to the low frequency side of the used frequency band are dominant, the ITS inter-vehicle communication system uses a filter with a simpler configuration than the in-vehicle wireless reception device shown in FIG. In this case, it is possible to avoid a state where the power of the desired signal in the used frequency band is suppressed as an interference wave when it leaks up to the guard band, and it is possible to reduce the possibility of reception failure.

  On the other hand, the desired signal / higher band side signal removal unit 43 can be replaced with the desired signal / lower band signal removal unit 53 having the gain characteristic G53 shown in FIG. .

  Each desired signal / low-band side signal removing unit 53 is a signal of a desired signal, a low-band guard band signal, and a signal of another system adjacent to the low-band side end of the use frequency band of the ITS inter-vehicle communication system. Remove everything. Each desired signal / low-frequency side signal removal unit 53 can be realized by, for example, a high-pass filter.

Here, assuming that the signal vector obtained from the system of the desired signal / low-frequency side signal removal unit 53 is Q ″ and the weight vector to be obtained is w, the weight control unit 6 minimizes the following evaluation function J _7. The weight is determined.
J ₇ = E | 0−w ^H Q ″ | ²

  According to the configuration shown in FIG. 18, for example, the use frequency band of the ITS inter-vehicle communication system is higher than the interference wave from another system adjacent to the low frequency side of the use frequency band of the ITS inter-vehicle communication system. When interference waves from other systems adjacent to the high frequency side of the used frequency band are dominant, the ITS inter-vehicle communication system uses a filter having a simpler configuration than the in-vehicle wireless reception device shown in FIG. In this case, it is possible to avoid a state where the power of the desired signal in the used frequency band is suppressed as an interference wave when it leaks up to the guard band, and it is possible to reduce the possibility of reception failure.

<Others>
In the fourth embodiment described above, the weight control unit 6 of the radio reception apparatus according to the first embodiment is replaced with the weight control unit 16 so that the output of the adder 8 is supplied to the weight control unit 16. Although the configuration of one embodiment has been changed, the configuration of the second embodiment, the configuration of the third embodiment, the configuration of the fifth embodiment, and the configurations of the two modifications of the fifth embodiment are the same. Can be changed.

  In the above-described embodiment, the desired signal extraction unit 2 is provided in each antenna system, but a configuration in which the desired signal extraction unit is not provided in each antenna system is also possible.

  In the above-described embodiment, the in-vehicle wireless reception device used in the ITS inter-vehicle communication system has been described as an example. However, ITS in which the use frequency band of another system is adjacent to both ends of the use frequency band. The present invention can also be applied to a wireless reception apparatus used in a wireless system other than the inter-vehicle communication system or a wireless system in which the use frequency band of another system is adjacent to only one end of the use frequency band.

  Further, the present invention can be applied not only to a wireless reception device that performs only reception, but also to a wireless transmission / reception device that performs transmission and reception.

These are the figures which show the frequency allocation around 720MHz in Japan. These are figures which show the state by which the vehicle-mounted radio | wireless receiver used by the ITS inter-vehicle communication system was mounted in the vehicle. These are figures which show schematic structure of the vehicle-mounted radio | wireless receiver which concerns on 1st embodiment of this invention. These are an example of an image figure at the time of seeing on the frequency axis the signal which each high frequency side guard band signal extraction part extracts. These are an example of the image figure at the time of seeing the signal which each low band side guard band signal extraction part extracts on a frequency axis. These are figures which show schematic structure of the vehicle-mounted wireless receiver which concerns on 2nd embodiment of this invention. These are an example of the image figure at the time of seeing on the frequency axis the signal which each high frequency side guard band signal and the other system signal extraction part extract. These are an example of an image figure at the time of seeing on the frequency axis the signal which each low band side guard band signal and other system signal extraction part extracts. These are figures which show schematic structure of the vehicle-mounted radio | wireless receiver which concerns on 3rd embodiment of this invention. These are an example of an image figure at the time of seeing on the frequency axis the signal which each high frequency side other system signal extraction part extracts. These are an example of an image figure at the time of seeing on the frequency axis the signal which each low frequency side other system signal extraction part extracts. These are figures which show schematic structure of the vehicle-mounted wireless receiver which concerns on 4th embodiment of this invention. These are figures which show schematic structure of the vehicle-mounted wireless receiver which concerns on 5th embodiment of this invention. These are figures which show the gain characteristic of a desired signal removal part. These are figures which show the modification of 5th embodiment of this invention. These are figures which show the gain characteristic of a desired signal and a high region side signal removal part. These are figures which show the gain characteristic of a desired signal and the low frequency side signal removal part. These are figures which show the other modification of 5th embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Desired signal extraction part 3 High band side guard band signal extraction part 4 Low band side guard band signal extraction part 5 A / D converter 6, 16 Weight control part 7 Weight multiplier 8 Adder 13 High band side guard band Signal / other system signal extraction unit 14 Low band side guard band signal / other system signal extraction unit 23 High band side other system signal extraction unit 24 Low band side other system signal extraction unit 33 Desired signal removal unit 43 Desired signal / high band side Signal removal unit 53 Desired signal / low frequency side signal removal unit 100 In-vehicle wireless reception device 200 used in ITS inter-vehicle communication 200 Vehicle

Claims (5)

A wireless reception device in which a frequency band of another system is adjacent to one or both ends of a channel band of a desired signal via a guard band,
A plurality of antenna elements;
A weighted adder that weights and outputs signals based on the received signals of the plurality of antenna elements; and
A signal detection unit for detecting at least one of a signal in a band of the guard band and a signal in a use frequency band of the other system from reception signals of the plurality of antenna elements;
A radio receiving apparatus comprising: a weight control unit that controls weighting of the weighting addition unit according to a signal detected by the signal detection unit.   The radio reception apparatus according to claim 1, wherein the weight control unit controls the weighting of the weighting addition unit so that the power of the signal detected by the signal detection unit is minimized.   The weight control unit controls weighting of the weighting addition unit so that a square error between a component corresponding to a known signal included in reception signals of the plurality of antenna elements and a reference signal is minimized. The wireless receiver according to claim 2. Until the synchronization processing for synchronizing the desired signals included in the reception signals of the plurality of antenna elements is completed, the weight control unit performs the weighting so that the power of the signal detected by the signal detection unit is minimized. Control the weight of the adder,
After the synchronization processing is completed, the weight controller adds the weight adder so that the square error between the component corresponding to the known signal included in the received signals of the plurality of antenna elements and the reference signal is minimized. The wireless receiving device according to claim 3, wherein weighting of the receiver is controlled. A desired signal extraction unit that extracts the desired signal for each antenna system from the reception signals of the plurality of antenna elements,
The radio reception apparatus according to any one of claims 1 to 4, wherein the weighting addition unit weights and adds the desired signal for each antenna system extracted by the desired signal extraction unit.

Images