JP2016146518A - Radio communication device and method for detecting channel occupation state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device which can detect a radio channel occupation state with a simple structure, without adding a change to a radio communication method.SOLUTION: A receiver 1000 includes a predetermined number of plurality of RF units 1200.1-1200.2 for converting signals from a plurality of antennas 1100.1-1100.2 into base band signals. To detect a radio channel occupation state, a sensing calculation unit 1330 divides a signal from one antenna by a divider 1120, to determine, based on cross correlation power calculated on each signal from the RF units 1200.1-1200.2, whether or not a radio channel through which communication is to be made is currently occupied.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radio communication apparatus and a radio channel occupation state detection method used in the radio communication apparatus.

  It is resistant to frequency selective fading in wireless communication systems such as LTE (Long Term Evolution) and LTE-A (Long Term Evolution-Advanced), which are mobile phone standards, or IEEE 802.11n / ac, which is a wireless LAN standard. OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multiple Input-Multiple Output) transmission technology to achieve high-speed transmission without expanding the frequency band by using multiple transmitting and receiving antennas Is adopted.

  As described above, in order to improve frequency utilization efficiency, an increasing number of communication devices adopt the MIMO scheme and have a plurality of antennas and a plurality of RF circuits.

  On the other hand, in recent years, effective utilization of frequency bands that are not used spatially and temporally is one of the means for improving frequency utilization efficiency to cope with the tightness of frequency resources and the explosive increase of mobile traffic. Are listed.

  1) Frequency sharing of wireless communication devices based on, for example, CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) (carrier sensing function) is realized between the same wireless systems such as wireless LAN communication terminals. Yes.

  2) Between different types of wireless systems, for example, 3GPP, a standardization organization, standardizes LAA (License Assisted Access) technology as a technology that enables LTE to be used in an unlicensed frequency band where a system such as a wireless LAN has already been used. Is being considered. Also, if there is an unused frequency band that is not used by the primary user among the frequencies allocated to the primary user using cognitive radio network technology, the secondary user A technique for communicating in an available frequency band (white space) among frequency bands has been proposed (for example, Patent Document 1).

  In such a wireless communication system that efficiently uses a frequency band by sharing a frequency with other users, it is necessary to appropriately grasp the spatial and temporal availability for each frequency.

  As a method for detecting the occupation state of the wireless channel by such other users, for example, there is a method using a spectrum sensing technique. In this method, the presence / absence of a spectrum at the position where the sensor (reception device) is arranged can be detected to detect the radio channel occupation status by other users.

  As a device for detecting an unused frequency spectrum, for example, a technique described in Non-Patent Document 1 is known.

JP 2013-183226 A

T. Yucek, “A Survey of Spectrum Sensing Algorithm for Cognitive Radio Applications,” IEEE Communications Surveys and Tutorials, Vol. 11, No. 1, 2009.

  However, in the technique described in Patent Document 1, it is necessary for the secondary user's communication device to add a ZP (Zero Padding) section to the guard interval section, or to change the communication format itself. There was a problem.

  Furthermore, Non-Patent Document 1 describes various methods related to spectrum sensing. Among the methods described in these, the simple method significantly deteriorates the detection accuracy when the noise power is relatively high with respect to the signal power. On the other hand, a highly accurate sensing method needs to know in advance the feature amount of a signal of a wireless system that performs frequency sharing, and the processing becomes complicated.

  The present invention has been made to solve the above-described problems, and its object is to detect the occupation status of a radio channel with high accuracy with a simple configuration without changing the radio communication system. It is to provide a wireless communication apparatus and a wireless channel occupation state detection method that can be performed.

  According to one aspect of the present invention, a wireless communication device includes a predetermined plurality of antennas and a signal switching unit for selectively switching a transmission path of signals from the predetermined plurality of antennas. The switching unit includes distribution means for dividing a signal from one of a plurality of predetermined antennas into a predetermined plurality and outputting from the signal switching unit, and is provided corresponding to each of the plurality of antennas. A plurality of predetermined high-frequency processing units for converting the output of the signal switching unit into a baseband signal, and a baseband processing unit for performing demodulation processing and decoding processing on the signal from the high-frequency processing unit The signal switching unit includes a first state in which signals from a plurality of predetermined antennas are transmitted to the corresponding high frequency processing units, and a signal from one antenna among the plurality of predetermined antennas. The wireless communication device is switched to any one of the second states in which the signal is transmitted to the distributing means, and in the second state, based on the cross-correlation power calculated for the signals from the predetermined plurality of high frequency processing units The apparatus further comprises sensing means for determining whether or not a wireless channel to be communicated with is available.

  Preferably, in the first state, the sensing means measures the received signal power for a signal from each of the predetermined plurality of antennas, and selects one antenna having the maximum received signal power in the second state. To do.

  Preferably, the sensing means determines that the radio channel is occupied when the maximum received signal power exceeds the first predetermined threshold.

  Preferably, the sensing means is responsive to the cross-correlation power not exceeding the predetermined second threshold when the maximum received signal power does not exceed the first predetermined threshold. Judge as unoccupied.

  Preferably, the baseband processing unit performs signal separation processing for MIMO (Multiple Input-Multiple Output) communication.

  According to another aspect of the present invention, wireless communication is performed in a wireless communication apparatus having a plurality of predetermined antennas and a plurality of predetermined high-frequency processing units for converting signals from the plurality of predetermined antennas into baseband signals. A wireless channel occupation state detection method for detecting a channel occupation state, wherein a signal from one antenna among a plurality of predetermined antennas is divided into a predetermined plurality of high frequency processing units Whether the radio channel to be communicated by the radio communication device is occupied based on the step of supplying the divided signals to each other and the cross-correlation power calculated for the signals from the predetermined plurality of high-frequency processing units Determining whether or not.

  Preferably, in a state where signals from the predetermined plurality of antennas are transmitted to the corresponding high frequency processing units, the received signal power is measured for the signals from each of the predetermined plurality of antennas, and the maximum received signal power is measured. The method further includes the step of specifying one antenna having the above, and in the step of supplying each of the divided signals, the signal from the specified one antenna is divided into a predetermined plurality.

  Preferably, the step of determining includes the step of determining that the radio channel is occupied when the maximum received signal power exceeds a first predetermined threshold.

  Preferably, the step of determining determines whether the cross-correlation power does not exceed the predetermined second threshold if the maximum received signal power does not exceed the first predetermined threshold. Determining that is unoccupied.

  Preferably, the wireless communication apparatus performs MIMO (Multiple Input-Multiple Output) communication using a predetermined plurality of antennas.

  According to the present invention, it is possible to detect the occupation state of the radio channel with a simple configuration without changing the radio communication system.

3 is a schematic block diagram for illustrating a configuration of a receiver 1000 of the wireless communication system according to the first embodiment. FIG. FIG. 10 is a diagram for explaining the state of each switch of the signal switching unit 1110. 10 is a flowchart for explaining processing performed by a sensing calculation unit 1330. 6 is a schematic block diagram for illustrating a configuration of receiver 2000 of the wireless communication system according to the second embodiment. FIG. FIG. 10 is a diagram for explaining the state of each switch of the signal switching unit 1110. 10 is a flowchart for explaining processing performed by a sensing calculation unit 1330.

Hereinafter, configurations of a wireless communication system and a wireless communication apparatus according to an embodiment of the present invention will be described. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.
[Embodiment 1]
FIG. 1 is a schematic block diagram for explaining a configuration of receiver 1000 of the wireless communication system according to the first embodiment.

  In FIG. 1, as an example, it is assumed that the number of antennas is two.

  Referring to FIG. 1, signals received by antenna 1100.1 and antenna 1100.2 are input to signal switching unit 1110.

  Signal switching unit 1110 includes switch circuit SW1 and switch circuit SW2 that receive signals from antenna 1100.1, and switch circuit SW1 and switch circuit SW3 that receive signals from antenna 1100.2. The switch circuit SW1 receives the signal from the antenna 1100.1 and the signal from the antenna 1100.2, and selectively supplies one of them to the input of the divider 1120 or the neutral state (which antenna Is also not connected to the divider 1120). Switch circuit SW2 selectively outputs a signal from antenna 1100.1 and one output of divider 1120. Switch circuit SW3 selectively outputs the signal from antenna 1100.2 and the other output of divider 1120. Divider 1120 divides the input signal into one output and the other output, and outputs the result.

  The operation of each switch circuit of the signal switching unit 1110 is controlled by the switch control unit 1400.

  An output from the signal switching unit 1110 is given to the baseband unit 1300 through the RF unit 1200.1 and the RF unit 1200.2.

  The output from the switch circuit SW2 is low-noise amplified by the RF unit 1200.1 and converted from an analog signal to a digital signal. In the baseband unit 1300, the demodulation unit 1310 performs demodulation processing.

  Similarly, the output from the switch circuit SW3 is amplified with low noise by the RF unit 1200.2 and converted from an analog signal to a digital signal. In the baseband unit 1300, the demodulation unit 1310 performs demodulation processing.

  Here, it is assumed that the demodulation unit 1310 performs signal demodulation processing using a well-known MIMO method.

  Although not particularly limited, for example, when MIMO in the OFDM communication scheme is adopted, the demodulation unit 1310 performs FFT processing to convert a time domain signal into a frequency domain signal, and performs FFT. (Fast Fourier Transform) Signal processing is performed on the signal for each subcarrier in the subsequent stage. .

  The decoding unit 1320 demaps the output of the demodulation unit 1310 on the constellation, and performs a deinterleaving process, an error correction process, and the like as necessary to obtain a decoded sequence.

  On the other hand, as will be described later, the sensing calculation unit 1330 determines that the wireless channel to be used by the receiver 1000 is based on outputs from the RF unit 1200.1 and the RF unit 1200.2. A determination process is performed to determine whether or not the channel is occupied by another device.

  The switch control unit 1400 controls each switch circuit of the signal switching unit 1110 according to the processing in the sensing calculation unit 1330.

  In the receiver 1000, when it is determined that a certain radio channel is empty, the information may be fed back to the transmitter side.

  FIG. 2 is a diagram for explaining the state of each switch of the signal switching unit 1110.

  Referring to FIG. 2, the state of signal switching unit 1110 shown in FIG. 1 is divided into three states, state 1, state 2, and state 3, and switch control unit 1400 changes the states of switch circuits SW1 to SW3. Control to either state.

  The state 1 is a state in which the baseband unit 1300 performs a communication signal reception process in the normal mode, is in an idle state of communication, or is a sensing initial process in the sensing calculation unit 1330 described later.

  In the state 1, the switch control unit 1400 controls the switch circuit SW1, the switch circuit SW2, and the switch circuit SW3 by transmitting signals of state codes “00”, “0”, and “0”, respectively. To do. At this time, the switch circuit SW1 is in a neutral position, the switch circuit SW2 is in a position connecting the antenna 1100.1 (antenna 1 in FIG. 2) and the RF unit 1200.1, and the switch circuit SW3 is 1100.2 (antenna 2 in FIG. 2) and the RF section 1200.2 are connected.

  In the state 2, the switch control unit 1400 controls the switch circuit SW1, the switch circuit SW2, and the switch circuit SW3 by transmitting signals of state codes “01”, “1”, and “1”, respectively. To do. At this time, the switch circuit SW1 is at a position connecting the antenna 1100.1 and the input of the divider 1120, and the switch circuit SW2 is at a position connecting one output of the divider 1120 and the RF unit 1200.1, and the switch circuit SW3. Is at a position connecting the other output of the divider 1120 and the RF section 1200.2.

  Therefore, in state 2, the sensing calculation unit 1330 divides the signal received by the same antenna 1100.1 into equal parts by the divider 1120 and processes them by different RF units 1200.1 and 1200.2. Based on the signal, the wireless channel will determine whether the channel is occupied by another wireless system or other device.

  In the state 3, the switch control unit 1400 controls the switch circuit SW1, the switch circuit SW2, and the switch circuit SW3 by transmitting signals of state codes “10”, “1”, and “1”, respectively. To do. At this time, the switch circuit SW1 is at a position connecting the antenna 1100.2 and the input of the divider 1120, and the switch circuit SW2 is at a position connecting one output of the divider 1120 and the RF unit 1200.1, and the switch circuit SW3. Is at a position connecting the other output of the divider 1120 and the RF section 1200.2.

  Therefore, in the state 3, as in the state 2, the sensing calculation unit 1330 divides the signal received by the same antenna 1100.2 into equal parts by the divider 1120, and the RF unit 1200.1 and the RF unit 1200 which are different from each other. Based on the signal processed in .2, it is determined whether the radio channel is occupied by another radio system or another device.

  In general, in a receiver configuration, noise generated in the RF section is often dominant. In this case, as described above, when signals from the same antenna are processed by a plurality of RF units, the noises generated in each RF unit among the noises included in the baseband signal are uncorrelated with each other. become.

  FIG. 3 is a flowchart for explaining processing performed by the sensing calculation unit 1330 in the configuration of FIG.

Referring to FIG. 3, when the process is started (S100), in the sensing initial process, switch control unit 1400 controls each switch of signal switching unit 1110 to be in state 1, and sensing calculation unit 1330 The received signal power P _i of each antenna is acquired by processing based on the following equation (S102).

Here, K is the number of samples for correlation calculation by time averaging, n indicates the timing of the current time, and * indicates a complex conjugate.

  Subsequently, the sensing calculation unit 1330 selects the antenna imax that maximizes the received power Pi (S104). Here, “antenna imax” means the imax antenna.

The sensing calculation unit 1330 compares the maximum received power Pi _max at the antenna imax with a predetermined threshold Threshold1, and if it is greater than the predetermined threshold Threshold1 (Y in S106), the sensing calculation unit 1330 The wireless channel to be used is determined to be occupied by another wireless system or another device (S120).

  On the other hand, when the sensing calculation unit 1330 is less than the predetermined threshold value Threshold1 (N in S106), the switch control unit 1400 then selects the signal switching unit 1110 based on the determination result from the sensing calculation unit 1330. Are controlled so as to transition to the state (imax + 1) (S110). For example, when the received power P1 of the antenna 1 is the maximum, each switch of the signal switching unit 1110 transitions to the state 2.

  The sensing calculation unit 1330 performs a process based on the following equation on the received baseband signal in which the signal from the antenna with the maximum received power is processed by the RF unit 1200.1 and the RF unit 1200.2, respectively. The signal from the part i, the signal from the RF part j, and the cross-correlation power Pij are calculated.

The RF unit i is a circuit that is provided corresponding to the antenna i and performs amplification and analog-digital conversion processing on the signal from the antenna i in the communication signal reception processing in the normal mode. For example, the antenna 1100.1 refers to the RF unit 1200.1.

  Subsequently, the sensing calculation unit 1330 compares the cross-correlation power Pij with a predetermined threshold Threshold2 using the following formula (S114).

Here, the coefficient 2 before the cross-correlation power Pij means 2, which is the number of antennas, and corresponds to correcting the signal power divided by the divider. .

  As described above, since the noise generated in the RF unit i and the RF unit j is considered to be uncorrelated, the cross-correlation power Pij is calculated if there is no signal of another radio or radio system in the radio channel to be sensed. The value will be extremely small.

  When the cross-correlation power is larger than the predetermined threshold Threshold2 (Y in S114), the sensing calculation unit 1330 occupies the wireless channel to be used by another wireless system or another device. (S120). On the other hand, if the cross-correlation power is less than the predetermined threshold value Threshold2 (N in S114), the sensing calculation unit 1330 occupies the channel that is to be used by another wireless system or other device. It is determined that it is not present (S130).

  Through the processing as described above, the receiver 1000 can determine whether or not the wireless channel to be used is occupied by another wireless system or another device.

  Note that the sensing initial process is not necessarily an essential process, and can be omitted if it is defined in advance that the subsequent process is performed by a signal from a predetermined antenna (for example, the antenna 1100.1). It is.

In addition, when implementing such a method for detecting the radio channel occupation status, a plurality of antennas used in the MIMO communication system and a plurality of antennas corresponding to these antennas are provided by additionally providing a signal switching unit. The RF channel occupancy status detection process can be executed using the RF unit. Therefore, a part of the configuration of the reception processing unit used for data communication in the normal mode is shared as the configuration for detecting the radio channel occupation status, and the radio channel occupation status can be detected with a simple device configuration. Can be executed.
[Embodiment 2]
In Embodiment 1, the number of antennas has been described as two. In the embodiment, a case where the number of antennas is larger will be described. Here, the description will be made assuming that the number of antennas is four as an example, but the number of antennas may be more than three as long as it is three or more.

  FIG. 4 is a schematic block diagram for explaining a configuration of receiver 2000 of the wireless communication system according to the second embodiment.

  Referring to FIG. 4, signals received by antennas 1100.1 to 1100.4 are input to signal switching unit 1110.

  Signal switching unit 1110 includes switch circuit SW1 that receives signals from all antennas 1100.1 to 1100.4, and switch circuits SW2 to SW5 that individually receive signals from antennas 1100.1 to 1100.4.

  The switch circuit SW1 selectively supplies one of the signals from the antennas 1100.1 to 1100.4 to the input of the divider 1120, or is in a neutral state (no antenna is connected to the divider 1120) )

  The switch circuit SWi (i = 2, 3, 4, 5) has a corresponding antenna 1100. The signal from (i-1) and the (i-1) th output of the divider 1120 are selectively output. The divider 1120 divides the input signal into four parts and outputs the first to fourth outputs.

  The operation of each switch circuit of the signal switching unit 1110 is controlled by the switch control unit 1400.

  The output from the signal switching unit 1110 is given to the baseband unit 1300 through the RF units 1200.1 to 1200.4, respectively.

  The output from the switch circuit SWi (i = 2, 3, 4, 5) is output from the corresponding RF unit 1200. Low noise amplification is performed at (i-1) and the analog signal is converted to a digital signal. In the baseband unit 1300, the demodulation unit 1310 performs demodulation processing.

  Here, it is assumed that the demodulation unit 1310 performs signal demodulation processing using a well-known MIMO method.

  Although not particularly limited, MIMO in the OFDM communication scheme may be employed in the second embodiment as well as in the first embodiment.

  The decoding unit 1320 demaps the output of the demodulation unit 1310 on the constellation, and performs a deinterleaving process, an error correction process, and the like as necessary to obtain a decoded sequence.

  On the other hand, as will be described later, the sensing calculation unit 1330 determines that the wireless channel to be used by the receiver 2000 is based on the outputs from the RF units 1200.1 to 1200.4. A determination process is performed to determine whether or not the channel is occupied by another device.

  The switch control unit 1400 controls each switch circuit of the signal switching unit 1110 according to the processing in the sensing calculation unit 1330.

  Even in the receiver 2000, when a certain radio channel is determined to be empty, the information may be fed back to the transmitter.

  FIG. 5 is a diagram for explaining the state of each switch of the signal switching unit 1110 shown in FIG.

  Referring to FIG. 5, the state of signal switching unit 1110 shown in FIG. 4 is divided into five states of state 1, state 2, state 3, state 4, and state 5, and switch control unit 1400 includes switch circuit SW1. Control the state of .about.SW5 to any one of these states.

  The state 1 is a state in which the baseband unit 1300 performs a communication signal reception process in the normal mode, is in an idle state of communication, or is a sensing initial process in the sensing calculation unit 1330 described later.

  In the state 1, the switch control unit 1400 controls the switch circuits SW1 to SW5 by transmitting signals of state codes “000”, “0”, “0”, “0”, “0”, respectively. Shall. At this time, the switch circuit SW1 is in the neutral position, and the switch circuits SWi (i = 2, 3, 4, 5) are respectively connected to the antennas 1100. (I-1) (antenna (i-1) in FIG. 5) and the RF unit 1200. It is in a position connecting (i-1).

  In state 2, the switch control unit 1400 controls the switch circuits SW1 to SW5 by transmitting signals of state codes “001”, “1”, “1”, “1”, and “1”, respectively. Shall. At this time, the switch circuit SW1 is at a position connecting the antenna 1100.1 and the input of the divider 1120, and the switch circuits SWi (i = 2, 3, 4, 5) are respectively connected to the first (i−1) th of the divider 1120. ) Output and RF section 1200. It is in a position connecting (i-1).

  Similarly, in the state i (i = 3, 4, 5), the switch control unit 1400 receives the antenna 1100. (I-1) A signal for selecting the side is controlled by transmitting signals of status codes “1”, “1”, “1”, “1” to the switch circuits SW2 to SW5, respectively. And At this time, the switch circuit SW1 includes the antenna 1100. (I-1) and the input of the divider 1120 are connected to each other, and the switch circuit SWi (i = 2, 3, 4, 5) is connected to the output (i-1) of the divider 1120 and the RF unit 1200. It is in a position connecting (i-1).

  Therefore, in the state i (i = 2, 3, 4, 5), the sensing calculation unit 1330 uses the same antenna 1100. The signal received in (i-1) is divided equally by the divider 1120, and based on the signals processed by the different RF units 1200.1 to 1200.4, the radio channel may be another radio system or other. It is determined whether the channel is occupied by the device.

  Again, in general, in the configuration of the receiver, when noise generated in the RF unit is dominant, as described above, when signals from the same antenna are processed in a plurality of RF units, basebands are obtained. Of the noise included in the signal, the noise generated in each RF unit is uncorrelated with each other.

  FIG. 6 is a flowchart for explaining processing performed by the sensing calculation unit 1330 in the configuration of FIG.

Referring to FIG. 6, when the process is started (S200), in the sensing initial process, switch control unit 1400 controls each switch of signal switching unit 1110 to be in state 1, and sensing calculation unit 1330 The received signal power P _i of each antenna is acquired by processing based on the following equation (S102).

Again, K is the number of samples for correlation calculation by time averaging, n indicates the timing of the current time, and * indicates a complex conjugate.

  Subsequently, the sensing calculation unit 1330 selects the antenna imax that maximizes the received power Pi (S204).

The sensing calculation unit 1330 compares the maximum received power Pi _max at the antenna imax with a predetermined threshold Threshold1, and if it is greater than the predetermined threshold Threshold1 (Y in S206), the sensing calculation unit 1330 The wireless channel to be used is determined to be occupied by another wireless system or another device (S220).

  On the other hand, when the sensing calculation unit 1330 is less than the predetermined threshold value Threshold1 (N in S206), the switch control unit 1400 then selects the signal switching unit 1110 based on the determination result from the sensing calculation unit 1330. Are controlled so as to transition to the state (imax + 1) (S210). For example, when the received power P1 of the antenna 1 is the maximum, each switch of the signal switching unit 1110 transitions to the state 2.

  The sensing calculation unit 1330 performs processing based on the following expression on the received baseband signal in which the signal from the antenna with the maximum received power is processed by the RF units 1200.1 to 1200.4, and performs the RF unit 1200. . i and the RF unit 1200. The signal from j and the cross-correlation power Pij are calculated.

N _RX is the number of antennas or the number of RF circuits corresponding to the number of antennas. i is the antenna 1100. This is a circuit that is provided corresponding to i (antenna i) and performs amplification and analog-digital conversion processing on the signal from antenna i in the communication signal reception processing in the normal mode.

  Therefore, the cross-correlation power Pij represents an average value of cross-correlation per pair of a plurality of antennas.

  Subsequently, the sensing calculation unit 1330 compares the cross-correlation power Pij with a predetermined threshold Threshold2 according to the following equation (S214).

Here, as described above, noise generated in the RF unit i and the RF unit j is considered to be uncorrelated. Therefore, if there is no signal of another radio or radio system in the radio channel to be sensed, the cross-correlation The electric power Pij becomes an extremely small value.

  When the cross-correlation power is larger than the predetermined threshold value Threshold2 (Y in S214), the sensing calculation unit 1330 occupies the wireless channel to be used by another wireless system or another device. Is determined (S220). On the other hand, when the cross-correlation power is less than the predetermined threshold value Threshold2 (N in S214), the sensing calculation unit 1330 occupies the channel that is about to be used by another wireless system or another device. It is determined that it is not present (S230).

  Also in this case, the sensing initial process is not necessarily an essential process, and will be omitted if it is defined in advance that the subsequent process is performed by a signal from a predetermined antenna (for example, antenna 1100.1). It is also possible.

  Through the processing as described above, the receiver 2000 can determine whether the wireless channel to be used is occupied by another wireless system or another device.

  Further, it is possible to achieve the same effect as that of the first embodiment.

  Embodiment disclosed this time is an illustration of the structure for implementing this invention concretely, Comprising: The technical scope of this invention is not restrict | limited. The technical scope of the present invention is shown not by the description of the embodiment but by the scope of the claims, and includes modifications within the wording and equivalent meanings of the scope of the claims. Is intended.

  1000, 2000 receiver, 1100.1 to 1100.4 antenna, 1110 signal switching unit, 1120 divider, SW1 to SW4 switch circuit, 1200.1 to 1200.4 RF unit, 1300 baseband unit, 1310 demodulating unit, 1320 decoding Part, 1330 sensing calculation part, 1400 switch control part.

Claims (10)

A wireless communication device,
A plurality of predetermined antennas;
A signal switching unit for selectively switching transmission paths of signals from the predetermined plurality of antennas;
The signal switching unit includes distribution means for dividing a signal from one of the predetermined plurality of antennas into the predetermined plurality and outputting from the signal switching unit,
A plurality of predetermined high-frequency processing units provided corresponding to the plurality of antennas, respectively, for converting the output of the signal switching unit into baseband signals;
A baseband processing unit for performing demodulation processing and decoding processing on the signal from the high frequency processing unit,
The signal switching unit transmits a signal from one antenna among the plurality of predetermined antennas, and a first state in which signals from the plurality of predetermined antennas are respectively transmitted to a corresponding high frequency processing unit. Switch to one of the second states to be transmitted to the distribution means,
In the second state, based on the cross-correlation power calculated for the signals from the predetermined plurality of high-frequency processing units, whether or not a radio channel to be communicated by the radio communication device is occupied A wireless communication apparatus further comprising sensing means for determining.   In the first state, the sensing means measures received signal power for signals from each of the predetermined plurality of antennas, and sets one antenna having the maximum received signal power in the second state. The wireless communication apparatus according to claim 1, which is selected.   The radio communication apparatus according to claim 2, wherein the sensing means determines that the radio channel is occupied when the maximum received signal power exceeds a first predetermined threshold.   The sensing means is responsive to the cross-correlation power not exceeding a predetermined second threshold when the maximum received signal power does not exceed a first predetermined threshold. The wireless communication device according to claim 2, wherein the wireless communication device determines that is unoccupied.   The wireless communication apparatus according to claim 1, wherein the baseband processing unit executes signal separation processing for MIMO (Multiple Input-Multiple Output) communication. A radio communication apparatus having a plurality of predetermined antennas and the predetermined plurality of high-frequency processing units for converting signals from the plurality of predetermined antennas into baseband signals, detects an occupation state of a radio channel A wireless channel occupancy status detection method for
Dividing a signal from one of the predetermined plurality of antennas into the predetermined plurality, and respectively supplying the divided signals to the predetermined plurality of high frequency processing units;
Determining whether or not a wireless channel to be communicated by the wireless communication device is occupied based on cross-correlation power calculated for signals from the predetermined plurality of high-frequency processing units, Wireless channel occupation status detection method. In a state where signals from the predetermined plurality of antennas are transmitted to the corresponding high frequency processing units, the received signal power is measured for the signals from each of the predetermined plurality of antennas, and the maximum received signal power is determined. Further comprising identifying one antenna having
The radio channel occupation state detection method according to claim 6, wherein in the step of supplying each of the divided signals, a signal from the specified one antenna is divided into the predetermined plurality.   8. The radio channel occupation state according to claim 7, wherein the determining step includes a step of determining that the radio channel is occupied when the maximum received signal power exceeds a first predetermined threshold. Detection method.   The determining step includes the step of determining whether the cross-correlation power does not exceed a predetermined second threshold when the maximum received signal power does not exceed a first predetermined threshold. The radio channel occupation state detection method according to claim 7, further comprising the step of determining that the channel is not occupied.   10. The radio channel occupation state detection method according to claim 6, wherein the radio communication device performs MIMO (Multiple Input-Multiple Output) communication using the predetermined plurality of antennas. 11.