JP2005268959A - Radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a radio receiver capable of obtaining sufficient gain by suppressing the change of an improper antenna that deteriorates communication quality. <P>SOLUTION: The radio receiver comprises a frame processor 15 for a frame that is transmitted from a communication device and is received, and an antenna change 20 for changing antennas 11, 12 used for reception, based on a frame processing result at least at the frame processor 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radio reception apparatus that includes a plurality of antennas and performs antenna switching according to a reception state.

  In wireless communication, communication quality may deteriorate due to a fading phenomenon in which the strength of received radio waves (received electric field strength) varies. For this reason, the diversity technique is used as the fading countermeasure.

  As an example of the diversity technique, there is a technique in which a radio reception apparatus is provided with a plurality of antennas, and when a received electric field intensity becomes a predetermined level or less, the antenna to be used is switched to receive radio waves. In addition to the received electric field strength, for example, the antenna may be switched based on the value of a signal-to-noise ratio (SNR) or modulation accuracy (EVM: Error Vector Magnitude) related to the received signal. Has been done. The antenna is referred to as a diversity antenna.

  A general radio receiving apparatus including the diversity antenna includes a receiving unit that is commonly used for the plurality of antennas in addition to the plurality of antennas. Here, an example of the configuration of the wireless reception device will be described with reference to FIG. Note that the radio reception device 90 shown in the figure is configured to switch antennas based on the received electric field strength, and is configured to include two antennas. In the following description, it is assumed that the wireless reception device 90 receives a signal (modulation signal) after the communication device modulates a frame created by a communication device that is a radio wave (signal) transmission source. .

  The wireless receiver 90 includes a first antenna 91, a second antenna 92, a receiver 93, a signal demodulator 94, a frame processor 95, a host processor 96, a comparator 97, and antenna switching, as shown in FIG. A portion 98 is provided. The receiving unit 93 includes a received electric field strength calculating unit 99.

  In the wireless reception device 90, a signal (modulated signal) from the outside is received by the first antenna 91 or the second antenna 92. In the figure, a state in which the second antenna 92 is used is shown.

  The receiving unit 93 receives a modulated signal via an antenna (second antenna 92 in the figure) connected to the receiving unit 93. Then, the receiver 93 sends a signal to the signal demodulator 94. The received electric field strength calculation unit 99 in the receiving unit 93 calculates the received electric field strength from the received modulation signal.

  The signal demodulator 94 demodulates the modulated signal sent via the receiver 93. Then, the demodulated signal (demodulated signal) is sent to the frame processing unit 95. The frame processing unit 95 creates a frame from the demodulated signal. More specifically, the frame processing unit 95 converts the modulated signal into header information such as a frame type, a transmission source address, a transmission destination address, payload data that is a frame body, an FCS (Frame Check Sequence). Restore to. Then, the frame processing unit 95 sends the header information, payload data, and FCS to the upper processing unit 96.

  For example, if the frame is a video frame, the upper processing unit 96 converts the frame into a format that can be displayed by a video display device (not shown). Further, the upper processing unit 96 performs the decryption process when the frame is subjected to the encryption process. In addition, depending on the frame, the wireless reception device needs to respond to the transmission device that is the transmission source of the frame. In such a case, the host processing unit 96 determines whether it is necessary to respond, and creates a transmission frame if necessary.

  The comparison unit 97 compares the received electric field strength calculated by the received electric field strength calculation unit 99 with a predetermined threshold value. Then, the comparison unit 97 sends an antenna switching instruction to the antenna switching unit 98 when the received electric field strength is smaller than the predetermined threshold. Note that the comparison unit 97 ends the process without sending an antenna switching instruction to the antenna switching unit 98 when the received electric field strength is larger than the predetermined threshold value.

  The antenna switching unit 98 switches the antenna used for communication between the first antenna 91 and the second antenna 92 in response to a switching instruction from the comparison unit 97. That is, the antenna connected to the receiving unit 93 is selectively switched. For example, in the figure, the second antenna 92 is used, but when the received electric field strength becomes smaller than a predetermined threshold, the antenna switching unit 98 switches the second antenna 92 to the first antenna 91.

Patent Document 1 discloses a receiver that improves diversity gain without degrading communication quality by switching antennas not only by the received field strength but also by taking into account the bit error rate of received data. It is disclosed.
JP-A-9-191305 (release date: July 22, 1997)

  However, the wireless receiver 90 has the following problems.

  For example, when the wireless reception device 90 and a plurality of wireless communication devices exist and communication is performed between the devices, radio waves and noise used in communication between devices other than the wireless reception device 90 are transmitted via an antenna. In some cases, the wireless reception device 90 receives the signal. If the received electric field strength of the received radio wave or noise is smaller than a predetermined threshold value, the antenna is switched. For this reason, the problem that the communication quality of the radio | wireless receiving apparatus 90 falls arises.

  Also in Patent Document 1, the following problems occur as in the wireless receiver.

  For example, when the receiver of Patent Document 1 and a plurality of wireless communication devices exist and communication is performed between the devices, radio waves and noise used in communication between devices other than the receiver are transmitted via an antenna. May be received by the receiver. If the bit error rate calculated from the received radio wave and noise is larger than a predetermined threshold, the antenna is switched. For this reason, the problem that the communication quality of the said receiver falls arises.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to obtain an appropriate gain (diversity gain) by suppressing inappropriate antenna switching that degrades communication quality. Is to provide a wireless receiving apparatus.

  In order to solve the above-described problem, a wireless reception device according to the present invention includes a plurality of antennas, and a wireless reception device that switches an antenna used for reception between the plurality of antennas is transmitted and received from a communication device. A frame processing unit that processes a frame and an antenna switching unit that switches an antenna used for reception based on at least a frame processing result of the frame processing unit.

  According to the above configuration, the antenna switching unit switches the antenna used for reception based on the frame processing result by the frame processing unit. Here, the frame processing result indicates the data itself included in the frame, and values that can be calculated when frame processing such as the frame error rate and the number of frame continuous errors is performed.

  Therefore, it is possible to perform highly accurate antenna switching as compared with a configuration in which the antenna is switched based on the received electric field strength and the bit error rate required at the time of signal modulation.

  Therefore, there is an effect that it is possible to provide a wireless reception device that can suppress an inappropriate antenna switching that degrades communication quality and can obtain a sufficient gain (diversity gain).

  The radio reception apparatus according to the present invention is the first identification for identifying whether the transmission destination of the frame is the own apparatus based on a frame processing result in the frame processing means in the radio reception apparatus. And when the transmission destination of the frame is its own device, the antenna switching means switches the antenna used for reception according to the reception state of the frame.

  According to the above configuration, the first identification unit can identify whether or not the transmission destination of the frame is the own apparatus based on the frame processing result in the frame processing unit. Then, when the transmission destination of the frame is the own apparatus, the antenna used for reception is switched by the antenna switching unit according to the reception state of the frame.

  By the way, when the transmission destination of the frame is not the own apparatus, if the antenna used for reception is switched according to the reception state of the frame, the own apparatus switches the antenna even though the frame is not addressed to the own apparatus. Sometimes. For this reason, there is a possibility that the reception state of the own device with respect to the frame addressed to the own device is deteriorated and the communication quality is deteriorated.

  However, the first identification means determines whether or not the transmission destination of the frame is the own device, and when the transmission destination of the frame is the own device, the necessity of antenna switching is determined to determine the frame addressed to the own device. There is no possibility that the reception state of the device itself deteriorates.

  Therefore, there is an effect that it is possible to provide a wireless reception device capable of suppressing an inappropriate antenna switching that deteriorates communication quality and obtaining a sufficient gain.

  Further, the wireless reception device according to the present invention includes a first identification unit for identifying whether or not the transmission destination of the frame is the own device based on a frame processing result in the frame processing unit, and the frame processing unit. Second identification means for identifying whether or not the type of the frame is a frame that requires real-time property based on the result of frame processing in step (b), and the transmission destination of the frame is the own device. When the frame type is a frame that requires real-time property, the antenna switching means switches the antenna used for reception according to the reception state of the frame.

  According to the above configuration, the first identification unit can identify whether or not the transmission destination of the frame is the own apparatus based on the frame processing result in the frame processing unit. Further, the second identification means identifies whether or not the type of the frame is a frame that requires real-time property based on the received frame. When the transmission destination of the frame is the own apparatus and the frame type is a frame requesting real-time property, the antenna switching unit performs reception according to the reception state of the frame. Switch the antenna to be used.

  By the way, when the transmission destination of the frame is not the own apparatus, if the antenna used for reception is switched according to the reception state of the frame, the own apparatus switches the antenna even though the frame is not addressed to the own apparatus. Sometimes. For this reason, there is a possibility that the reception state of the own device with respect to the frame addressed to the own device is deteriorated and the communication quality is deteriorated.

  Moreover, the frame which requires the real-time property generally has a long frame length. For this reason, there is a greater risk that an error may be applied to a frame due to the influence of noise or the like, or a part or all of the frame may be lost, compared to a frame that does not require real-time characteristics. Therefore, if a frame that requires real-time performance can be received with high accuracy, efficient reception can be realized.

  Therefore, as described above, when the transmission destination of a frame is the own apparatus and the frame type is a frame that requires real-time property, the antenna used for reception depends on the reception state of the frame. By switching between the two, there is an effect that efficient reception can be realized.

  Further, the wireless reception device according to the present invention includes a first identification unit for identifying whether or not the transmission destination of the frame is the own device based on a frame processing result in the frame processing unit, and the frame processing unit. Based on the result of frame processing at, second priority means for identifying whether or not the frame type is a frame that requires real-time property, and an index indicating the degree of request for real-time property of the frame is set as a priority In this case, based on the frame processing result in the frame processing means, the priority identifying means for identifying the priority of the frame, and whether the priority identified by the priority identifying means is higher than a predetermined degree. Determination means for determining whether or not the transmission destination of the frame is the own apparatus, and the frame type is a frame requesting real-time characteristics. A case where, and when the priority is higher than a predetermined degree, the antenna switching means, in response to the reception state of the frame, is characterized by switching the antenna used for reception.

  According to the above configuration, the first identification unit can identify whether or not the transmission destination of the frame is the own apparatus based on the frame processing result in the frame processing unit. Further, the second identification means identifies whether or not the type of the frame is a frame that requires real-time property based on the received frame. Further, the priority identifying unit identifies the priority of the frame based on the frame processing result in the frame processing unit. The determination unit compares the priority identified by the priority identification unit with a predetermined degree.

  When the transmission destination of the frame is its own device, and when the type of the frame is a frame that requires real-time properties, and when the priority is higher than a predetermined degree The antenna switching means switches the antenna used for reception according to the reception state of the frame.

  By the way, when the transmission destination of the frame is not the own apparatus, if the antenna used for reception is switched according to the reception state of the frame, the own apparatus switches the antenna even though the frame is not addressed to the own apparatus. Sometimes. For this reason, there is a possibility that the reception state of the own device with respect to the frame addressed to the own device is deteriorated and the communication quality is deteriorated.

  Moreover, the frame which requires the real-time property generally has a long frame length. For this reason, there is a greater risk that an error may be applied to a frame due to the influence of noise or the like, or a part or all of the frame may be lost, compared to a frame that does not require real-time characteristics. Therefore, if a frame that requires real-time performance can be received with high accuracy, efficient reception can be realized.

  Furthermore, if a frame requiring high real-time property among frames requiring real-time property can be received with high accuracy, even more efficient reception is possible.

  Therefore, as described above, the frame transmission destination is the own apparatus, and the frame type is a frame that requires real-time property, and the priority is higher than a predetermined degree. In this case, there is an effect that efficient reception can be realized by switching the antenna used for reception according to the reception state of the frame.

  Further, in the wireless reception device according to the present invention, in the wireless reception device described above, a storage unit that stores, for each communication device, a reception state of a frame addressed to itself by each antenna, and a transmission destination of the frame is not the own device. A third identification unit for identifying whether or not the received frame includes data indicating grant of a transmission right of the frame based on a result of the frame processing performed by the frame processing unit; and transmission to the received frame When data indicating the grant of the right is included, a fourth identification unit for identifying the communication device to which the transmission right is granted and the transmission right are granted based on the frame processing result in the frame processing unit For the communication device, based on the reading means for reading out the reception state of the frame addressed to the own device in each antenna from the storage means, It is characterized in that it comprises an antenna determining means for determining an antenna to be used for signal.

  According to the above configuration, when a frame whose transmission destination is not its own device is received, the third identification unit indicates granting of a frame transmission right to the received frame based on the frame processing result in the frame processing unit. Whether data is included is identified. When the received frame includes data indicating the grant of transmission right, the fourth identification unit identifies the communication device to which the transmission right is granted based on the frame processing result in the frame processing unit. The Therefore, the communication device having the next transmission right can be identified by the third identifying means and the fourth identifying means.

  Further, the storage means stores the reception state of the frame addressed to the own device at each antenna for each communication device. Then, with respect to the communication device to which the transmission right is given by the reading unit, the reception state of the frame addressed to the own device at each antenna can be read from the storage unit. In other words, the reading means can read from the storage means the reception state when each antenna is used for the communication apparatus having the next transmission right.

  Further, the antenna determining means determines an antenna for reception based on the read reception state. For example, the antenna having the best reception state may be determined as the antenna used for communication.

  Therefore, by switching the antenna used for reception according to the above determination, there is an effect that it is possible to improve the frame reception state in the own apparatus.

  In addition, in the wireless reception device according to the present invention, in the above wireless reception device, when the transmission destination of the frame is the own device, the storage means receives the frame transmission source and the antenna used for reception. It is characterized by comprising writing means for writing in association with the state.

  According to the above configuration, when the transmission destination of the frame is its own device, the writing means writes the frame transmission source in association with the communication state at the antenna used for reception in the storage means. Is included.

  Therefore, information on the reception state can be stored in the storage means. Therefore, in the subsequent antenna switching process, the reception state information written by the writing means can be used.

  Further, the wireless reception device according to the present invention is the above wireless reception device, wherein the frame length calculation means for calculating the frame length based on the received frame, and whether the calculated frame length is a predetermined length or more. Frame length judging means for judging whether or not, and when the frame length is equal to or longer than a predetermined length, the antenna switching means switches an antenna used for reception according to a reception state of the frame. Yes.

  According to the above configuration, the frame length determination unit can determine whether or not the frame length calculated by the frame length calculation unit is greater than or equal to a predetermined length. And when the frame length of the said frame is more than predetermined length, an antenna switching means switches the antenna utilized for reception according to the reception state of the said frame.

  By the way, a frame with a long frame length is stronger than a frame with a short frame length in that there is a risk that an error may be caused in the frame due to the influence of noise or the like, or a part or all of the frame may be lost. Therefore, if a frame with a long frame length can be received with high accuracy, efficient reception can be realized.

  Therefore, when the frame length is equal to or longer than a predetermined length, there is an effect that efficient reception can be realized by switching the antenna used for reception according to the reception state of the frame.

  Further, the wireless reception device according to the present invention is the above wireless reception device, wherein a modulation rate calculation means for calculating a modulation rate based on the received frame and whether the calculated modulation rate is equal to or higher than a predetermined rate. Modulation rate determination means for determining whether or not the antenna switching means switches the antenna used for reception according to the reception state of the frame when the modulation speed is equal to or higher than a predetermined speed.

  According to the above configuration, the modulation speed determination means can determine whether the modulation speed calculated by the modulation speed calculation means is equal to or higher than a predetermined speed. And when the said modulation speed is more than predetermined speed, an antenna switching means switches the antenna utilized for reception according to the reception state of the said frame.

  By the way, a frame with a high modulation speed is more likely to have an error in the frame due to the influence of noise or the like than a frame with a low modulation speed. Therefore, if a frame with a high modulation speed can be received with high accuracy, efficient reception can be realized.

  Therefore, when the modulation rate is equal to or higher than a predetermined rate, there is an effect that efficient reception can be realized by switching the antenna used for reception according to the reception state of the frame.

  Further, the wireless reception device according to the present invention is the above wireless reception device, wherein the reception field strength calculation means for calculating the reception field strength based on the received frame, the calculated reception field strength, a predetermined threshold value, and And the reception state is indicated by the received electric field strength, and when the received electric field strength is smaller than the predetermined threshold, the antenna switching means selects an antenna used for reception. It is characterized by switching.

  According to the above configuration, the received electric field strength is calculated by the received electric field strength calculating means based on the received frame. The comparison means compares the calculated received electric field strength with a predetermined threshold value. And when the said received electric field strength is smaller than the said predetermined threshold value, an antenna switching means switches the antenna used for reception.

  That is, the antenna is switched when the received electric field strength is below a certain level (when the reception state is not good).

  Therefore, the antenna can be switched based on the received electric field strength indicating the reception state.

  The radio reception apparatus according to the present invention, in the radio reception apparatus described above, compares modulation accuracy calculation means for calculating modulation accuracy based on the received frame, and compares the calculated modulation accuracy with a predetermined threshold value. Comparing means, and the communication state is indicated by the modulation accuracy, and when the modulation accuracy is higher than the predetermined threshold, the antenna switching means switches the antenna used for reception. It is a feature.

  According to the above configuration, the modulation accuracy is calculated by the modulation accuracy calculation means based on the received frame. Further, the comparison means compares the calculated modulation accuracy with a predetermined threshold value. When the modulation accuracy is higher than the predetermined threshold, the antenna switching means switches the antenna used for reception.

  That is, when the modulation accuracy becomes a certain level or more (when the reception state is not good), the antenna is switched.

  Therefore, the antenna can be switched based on the modulation accuracy indicating the reception state.

  Further, the wireless reception device according to the present invention is the above-described wireless reception device, wherein the signal-to-noise ratio calculation means for calculating the signal-to-noise ratio based on the received frame, the calculated signal-to-noise ratio, Comparing means for comparing with a threshold value of the antenna, the communication state is indicated by the signal-to-noise ratio, and when the signal-to-noise ratio is smaller than the predetermined threshold value, the antenna switching means The antenna used for reception is switched.

  According to the above configuration, the signal-to-noise ratio is calculated by the signal-to-noise ratio calculation means based on the received frame. The comparison means compares the calculated signal-to-noise ratio with a predetermined threshold value. When the signal-to-noise ratio is smaller than the predetermined threshold, the antenna switching unit switches the antenna used for reception.

  That is, when the signal-to-noise ratio is below a certain level (when the reception state is not good), the antenna is switched.

  Therefore, the antenna can be switched based on the signal-to-noise ratio indicating the reception state.

  Further, the wireless reception device according to the present invention is the above-described wireless reception device, wherein the bit error rate calculation means for calculating the bit error rate based on the received frame, the calculated bit error rate, a predetermined threshold value, And the reception state is indicated by the bit error rate, and when the bit error rate is higher than the predetermined threshold, the antenna switching unit selects an antenna used for reception. It is characterized by switching.

  According to the above configuration, the bit error rate is calculated by the bit error rate calculation means based on the received frame. Further, the calculated bit error rate is compared with a predetermined threshold value by the comparison means. When the bit error rate is higher than the predetermined threshold, the antenna switching unit switches the antenna used for reception.

  That is, when the bit error rate exceeds a certain level (when the reception state is not good), the antenna is switched.

  Therefore, the antenna can be switched based on the bit error rate indicating the reception state.

  Further, the wireless reception device according to the present invention is the above wireless reception device, wherein the frame error rate calculation means for calculating a frame error rate based on the received frame, the calculated frame error rate, a predetermined threshold value, And the reception state is indicated by the frame error rate, and when the frame error rate is higher than the predetermined threshold, the antenna switching unit selects an antenna used for reception. It is characterized by switching.

  According to the above configuration, the frame error rate is calculated by the frame error rate calculation means based on the received frame. Further, the comparison means compares the calculated frame error rate with a predetermined threshold value. When the frame error rate is higher than the predetermined threshold, the antenna used for reception is switched.

  That is, when the frame error rate exceeds a certain level (when the reception state is not good), the antenna switching unit switches the antenna.

  Therefore, there is an effect that the antenna can be switched based on the frame error rate indicating the reception state.

  Further, the radio reception apparatus according to the present invention is the radio reception apparatus described above, wherein continuous error calculation means for calculating the number of consecutive errors of the frame based on the received frame, the number of consecutive errors of the calculated frame, And the reception state is indicated by the number of consecutive errors in the frame, and the antenna switching means is provided when the number of consecutive errors in the frame is greater than the predetermined threshold. Is characterized by switching the antenna used for reception.

  According to the above configuration, the continuous error frequency calculation means calculates the continuous error frequency of the frame based on the received frame. Further, the comparison means compares the calculated number of consecutive frame errors with a predetermined threshold value. When the number of continuous errors in the frame is greater than the predetermined threshold, the antenna switching unit switches the antenna used for reception.

  That is, when the number of consecutive frame errors reaches a certain level (when reception is not good), the antenna is switched.

  Therefore, there is an effect that the antenna can be switched based on the number of consecutive errors in the frame indicating the reception state.

  As described above, the wireless reception device according to the present invention is used for reception based on a frame processing unit that processes a received frame transmitted from the communication device and at least a frame processing result in the frame processing unit. Since the antenna switching means for switching the antenna is provided, it is possible to obtain a sufficient gain by suppressing inappropriate antenna switching that lowers the communication quality.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 is a functional block diagram of radio receiving apparatus 1 according to the present embodiment. As shown in the figure, the radio receiving apparatus 1 includes a first antenna 11, a second antenna 12, a receiving unit 13, a signal demodulating unit 14, a frame processing unit 15, a higher order processing unit 16, a first identification unit (first identification unit). Means) 17, a second identification unit (second identification unit) 18, a comparison unit (comparison unit) 19, and an antenna switching unit (antenna switching unit) 20. The receiving unit 13 includes a received electric field strength calculating unit (received electric field strength calculating unit) 21.

  In the following description, it is assumed that the wireless reception device 1 receives a signal (modulated signal) after the communication device modulates a frame created by a communication device that is a radio wave (signal) transmission source. . The same applies to the radio receiving apparatus 1 'according to the second embodiment described later.

  In addition, the first antenna 11, the second antenna 12, the receiving unit 13, the signal demodulating unit 14, the higher order processing unit 16, and the antenna switching unit 20 are respectively the first antenna 91 and the second antenna described as the prior art. Since the antenna 92, the receiving unit 93, the signal demodulating unit 94, the higher order processing unit 96, and the antenna switching unit 98 have the same functions, descriptions thereof are omitted here.

  The frame processing unit 15 receives the demodulated signal from the signal demodulating unit 14. Then, the frame processing unit 15 creates a frame from this demodulated signal. More specifically, the frame processing unit 15 restores the modulated signal into header information such as a frame type, a transmission source address, a transmission destination address, payload data that is a frame body, and FCS. Then, the frame processing unit 15 sends the header information, payload data, and FCS to the upper processing unit 16. These functions are the same as those of the frame processing unit 95 described above.

  In addition to the above functions, the frame processing unit 15 notifies the first identification unit 17 and the second identification unit 18 of the header information of the frame.

  Here, an example of the format of the frame created by the frame processing unit 15 will be described with reference to FIG. This frame is composed of a plurality of fields. Specifically, the frame is Frame Control (Frame Control), Duration / ID, Address1, Address2, Address3, Sequence Control (sequence control), Address4, QoS (Quality of Service) Control (service quality control), Frame Body ( Frame body) and FCS. Note that the Frame Control, Duration / ID, Address1, Address2, Address3, Sequence Control, Address4, and QoS Control correspond to the header information.

  The Frame Control is a field indicating the type of frame. The Address 1 is a field indicating the address of the frame transmission source. Further, Address2 is a field indicating the address of the transmission destination of the frame. The QoS control is a field indicating the priority of the QoS data frame. Here, the priority is an index indicating the required degree of real-time frame. Note that description of other fields in the frame is omitted.

  The received electric field strength calculating unit 21 calculates the received electric field strength from the modulated signal received by the receiving unit 13. Then, the received electric field strength calculating unit 21 sends data indicating the calculated received electric field strength (hereinafter referred to as received electric field strength data) to the comparing unit 19.

  The first identification unit 17 identifies whether the transmission destination of the frame is the own device (wireless reception device 1) based on the frame. Specifically, based on the field of Address 2 (transmission destination address) in the frame, it is identified whether or not the transmission destination of the frame is its own device. Further, when the first identification unit 17 identifies that the transmission destination of the frame is the own device, the first identification unit 17 notifies the second identification unit 18 of information indicating that the transmission destination of the frame is the own device.

  When receiving the information indicating that the transmission destination of the frame is the own apparatus, the second identification unit 18 identifies whether or not the frame type is a frame that requires real-time property based on the frame. In the present embodiment, as an example of a frame requesting the real-time property, the second identification unit 18 identifies whether or not the frame type is a QoS data frame.

  When the frame type is a QoS data frame, the second identification unit 18 notifies the comparison unit 19 of information indicating that the frame type is a QoS data frame. Note that the frame type is a QoS data frame indicates that the frame type is a frame that guarantees QoS.

  The comparison unit 19 first receives reception field strength data from the reception field strength calculation unit 21. Further, when information indicating that the frame type is a QoS data frame is received from the second identification unit 18, the received electric field strength is compared with a predetermined threshold value. Then, the comparison unit 19 sends an antenna switching instruction to the antenna switching unit 20 when the received electric field strength is smaller than a predetermined threshold.

  The antenna switching unit 20 switches the antenna used for communication between the first antenna 11 and the second antenna 12 in response to a switching instruction from the comparison unit 19. That is, the antenna connected to the receiving unit 13 is selectively switched. For example, in the figure, the second antenna 12 is used. However, when the received electric field strength becomes smaller than a predetermined threshold, the antenna switching unit 20 switches the second antenna 12 to the first antenna 11.

  As described above, the wireless reception device 1 is based on the frame processing result in the frame processing unit 15 and identifies whether the transmission destination of the frame is the first device (first identification). Means) 17, and when the transmission destination of the frame is the own apparatus 1, the antennas (11 and 12) used for reception are switched according to the reception state of the frame (reception state indicated by the received electric field strength) It is a configuration.

  According to the above configuration, the first identification unit 17 can identify whether the transmission destination of the frame is the device 1 based on the received frame. Then, when the transmission destination of the frame is the device 1, the antennas (11 and 12) used for reception are switched according to the reception state of the frame.

  By the way, when the transmission destination of the frame is not the own apparatus, if the antenna used for reception is switched according to the reception state of the frame, the own apparatus switches the antenna even though the frame is not addressed to the own apparatus. The problem arises. For this reason, there is a possibility that the reception state in the own device with respect to the frame addressed to the own device is deteriorated and the communication quality is deteriorated.

  However, in the wireless reception device 1, the first identification unit 17 determines whether or not the transmission destination of the frame is the own device, and determines the necessity of antenna switching when the transmission destination of the frame is the own device 1. Thus, there is no possibility that the reception state of the frame addressed to the own apparatus will deteriorate.

  Therefore, in the wireless reception device 1, inappropriate antenna switching that lowers the communication quality can be suppressed, and as a result, a sufficient gain can be obtained.

  Further, the wireless reception device 1 uses a second identification unit 18 (second identification) for identifying whether or not the type of the frame is a frame that requires real-time property based on a frame processing result in the frame processing unit. And the frame is used for reception according to the reception state of the frame when the transmission destination of the frame is the own apparatus and the type of the frame is a frame that requires real-time characteristics. It is also the structure which switches an antenna (11 * 12).

  According to said structure, it is discriminate | determined by the 2nd identification part 18 based on the received frame whether the kind of said frame is a flame | frame which requires real-time property. When the frame type is a frame that requires real-time characteristics, the antennas (11 and 12) used for reception are switched according to the reception state of the frame.

  Here, the frame requiring the real-time property generally has a long frame length. For this reason, there is a greater risk that a frame with an error may be received or a part or all of the frame may be lost due to the influence of noise or the like, compared to a frame that does not require real-time performance. Therefore, efficient communication can be realized if a frame requiring real-time performance can be received with high accuracy.

  Therefore, in the wireless reception device 1, as described above, when the frame type is a frame that requires real-time performance, the efficiency is improved by switching the antenna used for communication according to the reception state of the frame. Good reception can be realized.

  Next, the flow of the antenna switching process in the radio receiving apparatus 1 will be described based on the flowchart of FIG.

  First, radio waves (signals) are received by any of the antennas (11, 12) (S1). Here, one of the antennas is an antenna that has been used until immediately before receiving the radio wave. After S1, the received electric field strength calculation unit 21 calculates the received electric field strength (S2). After S2, the signal demodulator 14 demodulates the signal (S3).

  After S3, based on the demodulated signal, the frame processing unit 15 performs frame processing to create a frame (S4). After S4, the first identification unit 17 identifies whether or not the transmission destination of the frame is the own apparatus based on the frame (S5).

  In S5, when the transmission destination of the frame is not the own apparatus (in the case of No), the process is terminated without performing the antenna switching process. On the other hand, in S5, when the transmission destination of the frame is its own device (in the case of Yes), the second identifying unit 18 identifies whether or not the frame type is a QoS data frame (S6).

  In S6, if the frame type is not a QoS data frame (No), the process is terminated without performing the antenna switching process. On the other hand, when the frame type is a QoS data frame (in the case of Yes), the comparison unit 19 compares the received electric field strength calculated by the received electric field strength calculation unit 21 with the predetermined threshold value. Specifically, it is determined whether or not the received electric field strength is smaller than a predetermined threshold (S7).

  In S7, when the received electric field strength is larger than the predetermined threshold (in the case of No), the process is terminated without performing the antenna switching process. On the other hand, when the received electric field strength is smaller than the predetermined threshold (in the case of Yes), antenna switching processing is performed by the antenna switching unit 20 (S8). After S8, the process ends.

  Note that the step of calculating the received electric field intensity indicated by S2 is not necessarily performed before the signal demodulating step indicated by S3, and may be performed at least by the step indicated by S7.

  In the above description, the configuration including two antennas has been described as an example, but the number of antennas is not limited to two.

  In the above description, the second identification unit 18 is provided, and the second identification unit 18 is configured to identify whether or not the frame type is a QoS data frame. It is good also as a structure which is not provided with the 2nd identification part 18. FIG.

  That is, when the first identification unit 17 identifies that the transmission destination of the frame is its own device, the first identification unit 17 sends information indicating that the transmission destination of the frame is its own device to the comparison unit 19. It is good also as a structure which transmits. In this case, when receiving the information, the comparison unit 19 compares the received electric field strength with a predetermined threshold value as described above. As a result, if the received electric field strength is smaller than the predetermined threshold value, the antenna switching unit An antenna switching instruction may be sent to 20.

  In the above description, the wireless reception device 1 includes the reception electric field strength calculation unit 21, and the comparison unit 19 compares the reception electric field strength with a predetermined threshold value to determine whether the antenna switching process is performed. However, the present invention is not limited to this.

  For example, the frame processing unit 15 is provided with a frame error rate calculation unit (frame error calculation unit) that calculates a frame error rate, and the comparison unit 19 determines the frame error rate calculated by the frame error rate calculation unit and a predetermined threshold value. It is good also as a structure to compare. In this case, when the frame error rate is higher than a predetermined threshold, the comparison unit 19 may be configured to instruct the antenna switching unit 20 to switch the antenna.

  Further, the frame processing unit 15 is provided with a continuous error calculation unit (continuous error calculation means) for calculating the number of continuous errors in the frame, and a comparison unit that compares the number of continuous errors in the frame calculated by the continuous error calculation unit with a predetermined threshold value. It is good also as a structure compared with 19. In this case, the comparison unit 19 may instruct the antenna switching unit 20 to switch the antenna when the number of consecutive frame errors is greater than a predetermined threshold.

  Note that the number of consecutive frame errors is the number of times that an event “an antenna switching target frame has been received but an error has been detected” has occurred continuously. In this case, “error” refers to an error in the frame.

  Further, the signal demodulating unit 14 is provided with a bit error rate calculating unit (bit error calculating means) for calculating a bit error rate, and the bit error rate calculated by the bit error rate calculating unit and a predetermined threshold value are compared by the comparing unit 19. It is good also as a structure to compare. In this case, when the bit error rate is higher than a predetermined threshold, the comparison unit 19 may be configured to instruct the antenna switching unit 20 to switch the antenna.

  The signal demodulator 14 is provided with a signal-to-noise ratio calculator (signal-to-noise ratio calculator) for calculating a signal-to-noise ratio (SNR), and the signal-to-noise ratio calculated by the signal-to-noise ratio calculator The comparison unit 19 may compare the predetermined threshold value. In this case, when the signal-to-noise ratio is smaller than a predetermined threshold, the comparison unit 19 may be configured to instruct the antenna switching unit 20 to switch the antenna.

  Further, the signal demodulation unit 14 is provided with a modulation accuracy calculation unit (modulation accuracy calculation means) for calculating the modulation accuracy (EVM), and the modulation accuracy calculated by the modulation accuracy calculation unit is compared with a predetermined threshold by the comparison unit 19. It is good also as composition to do. In this case, when the modulation accuracy is higher than a predetermined threshold, the comparison unit 19 may be configured to instruct the antenna switching unit 20 to switch the antenna.

  Furthermore, as a configuration for determining whether to switch antennas using two or more of received electric field strength, frame error rate, number of consecutive frame errors, bit error rate, signal-to-noise ratio, and modulation accuracy Also good. As a specific example, the antenna may be switched when the received electric field strength is smaller than a predetermined threshold and the frame error rate is larger than the predetermined threshold.

  By the way, in the above embodiment, when the type of frame is a frame that requires real-time property, the configuration in which the antenna used for reception is switched according to the reception state is shown. Only when the degree is high, the antenna used for reception may be switched.

  That is, when an index indicating the degree of request for real-time frame is used as the priority, a priority identifying unit (priority identifying unit) that identifies the priority of the frame based on the frame processing result in the frame processing unit 15. And a priority judgment unit (priority judgment means) for judging whether or not the priority identified by the priority identification means is higher than a predetermined degree, and the transmission destination of the frame is the own device If the frame type is a frame that requires real-time characteristics and the priority is higher than a predetermined level, reception is performed according to the reception state of the frame. It is good also as a structure which switches the antenna to be used.

  In this configuration, among frames that require real-time performance, a frame that has a high real-time performance requirement can be received with high accuracy, so that more efficient reception is possible.

  In the above-described embodiment, the configuration in which the antenna used for reception is switched according to the reception state of the frame when the transmission destination of the frame is the own apparatus has been described. However, the present invention is not limited to this. That is, regardless of the transmission destination of the frame, the antenna used for reception may be switched based on the frame processing result in the frame processing unit. The frame processing result is a value that can be calculated when the frame processing such as the data itself (see FIG. 2) included in the frame, the frame error rate, and the number of continuous errors of the frame is performed.

  In the case of this configuration, it is possible to perform highly accurate antenna switching as compared with a configuration in which the antenna is switched based simply on the received electric field strength and the bit error rate required at the time of signal modulation. Therefore, even with this configuration, it is possible to obtain an adequate gain (diversity gain) by suppressing inappropriate antenna switching that degrades communication quality.

  Also, the signal demodulator 14 determines a frame length calculator (frame length calculator) that calculates a frame length based on the received frame, and determines whether the calculated frame length is equal to or greater than a predetermined length. A frame length determination unit (frame length determination unit), and when the frame length is equal to or longer than a predetermined length, the antenna switching unit 20 switches an antenna used for reception according to a reception state of the frame. It is good also as a structure.

  Here, a frame with a long frame length is stronger than a frame with a short frame length in that there is a risk that an error may be caused in the frame due to the influence of noise or the like, or a part or all of the frame may be lost. Therefore, if a frame with a long frame length can be received with high accuracy, efficient reception can be realized. Therefore, when the frame length is equal to or longer than a predetermined length, efficient reception can be realized by switching the antenna used for reception according to the reception state of the frame.

  Further, the signal demodulator 14 includes a modulation rate calculator (modulation rate calculator) that calculates a modulation rate based on the received frame, and a modulation that determines whether the calculated modulation rate is equal to or higher than a predetermined rate. A configuration including a speed determining unit (modulation rate determining means), and when the modulation rate is equal to or higher than a predetermined rate, the antenna switching unit 20 switches an antenna used for reception according to a reception state of the frame It is good.

  The modulation speed (modulation rate) refers to header information, frame body, and FCS modulation rate. This modulation rate field is not shown in FIG. 2, but is stored before the header information (the frame length field is the same). The signal demodulator 14 demodulates the header information, the frame body, and the FCS based on the modulation speed information.

  Here, a frame with a high modulation speed is more likely to have an error in the frame due to the influence of noise or the like than a frame with a low modulation speed. Therefore, if a frame with a high modulation speed can be received with high accuracy, efficient reception can be realized. Therefore, when the modulation rate is equal to or higher than a predetermined rate, efficient reception can be realized by switching the antenna used for reception according to the reception state of the frame.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. 4 and FIG. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 4 is a functional block diagram of radio receiving apparatus 1 ′ according to the present embodiment. As shown in the figure, the radio receiving apparatus 1 'includes a first antenna 11, a second antenna 12, a receiving unit 13, a signal demodulating unit 14, a frame processing unit 15', an upper processing unit 16, a first identification unit (first identification unit). 1 identifying means) 17 ', second identifying section (second identifying means) 18, comparing section (comparing means) 19, antenna switching section (antenna switching means) 20', third identifying section (third identifying means) 22, A fourth identification unit (fourth identification unit) 23, a fifth identification unit 24, a data writing processing unit (writing unit) 25, a storage unit (storage unit) 26, a data reading processing unit (reading unit) 27, and An antenna determination unit (antenna determination means) 28 is provided. The reception unit 13 includes a reception field strength calculation unit (reception field strength calculation means) 21 ′.

  The frame processing unit 15 ′ converts the header information of the frame described in the first embodiment into the first identifying unit 17 ′, the second identifying unit 18, the third identifying unit 22, the fourth identifying unit 23, and the fifth identifying unit. Except for notifying the identification unit 24, the same processing as that of the frame processing unit 15 of the first embodiment is performed. The received electric field strength calculating unit 21 ′ notifies the calculated received electric field strength to the comparing unit 19 and the data writing processing unit 25.

  The first identification unit 17 ′ identifies whether or not the transmission destination of the frame is the own device (radio reception device 1 ′) based on the frame created by the frame processing unit 15 ′. This identification is the same as the first identification unit 17 of the first embodiment.

  In the following, each functional block is divided into a case where the first identifying unit 17 ′ identifies that “the transmission destination of the frame is its own device” and a case where it identifies that “the transmission destination of the frame is not its own device”. The function of will be described.

  First, a case where the first identification unit 17 ′ identifies that “the transmission destination of the frame is the own apparatus” will be described.

  In this case, the first identification unit 17 ′ notifies the second identification unit 18 of information indicating that the transmission destination of the frame is its own device. Note that the processing in the second identification unit 18 and the comparison unit 19 has been described in the first embodiment, and thus will be omitted. However, the comparison unit 19 is configured to send a switching instruction to the antenna switching unit 20 ′ instead of the antenna switching unit 20 of the first embodiment.

  The antenna switching unit 20 ′ notifies the data writing processing unit 25 of information indicating the antenna being used (the first antenna 11 or the second antenna 12). In this notification, for example, information “1” is notified in the case of the first antenna 11 and information “2” is notified in the case of the second antenna.

  The method of notifying the information by the antenna switching unit 20 ′ is not particularly limited. For example, it is good also as a structure which notifies the information which shows the said antenna with respect to the data writing process part 25, whenever the switching process of an antenna is performed. Alternatively, the antenna switching unit 20 ′ is configured to store information indicating the currently used antenna, and the first identification unit 17 ′, for example, transmits data to the data writing processing unit 25 with respect to the antenna switching unit 20 ′. An instruction may be sent to transmit information indicating the antenna. Alternatively, the fifth identification unit 24 may send the instruction instead of the first identification unit 17 ′.

  The fifth identification unit 24 identifies the wireless communication device that is the transmission source of the frame based on the frame created by the frame processing unit 15. Specifically, the source address is identified based on the Address 1 (source address) field in the frame. Then, the fifth identification unit 24 notifies the data write processing unit 25 of the identified transmission source address.

  The storage unit 26 includes a table as shown in FIG. 5 that uses as parameters the address of the wireless communication apparatus that is the transmission source (address of the transmission source) and each antenna (11, 12). As will be described in detail later, the received field strength is written in the table corresponding to the address of the transmission source and the antenna.

  The data writing processing unit 25 receives information indicating the antenna being used from the antenna switching unit 20 ′, received field strength data from the received field strength calculating unit 21 ′, and the transmission source from the fifth identifying unit 24. Receive the address. Then, the data write processing unit 25 writes the received electric field strength in the storage unit 26 based on the antenna used and the address of the transmission source.

  In addition, when the antenna switching process is performed by the antenna switching unit 20 ′, the data writing processing unit 25 uses the antenna after the switching based on the antenna used after the switching and the address of the transmission source. The received electric field strength at the antenna is written in the storage unit 26.

  When the transmission source wireless communication device is changed to another wireless communication device, the data writing processing unit 25 uses the address of the other wireless communication device (transmission source address) and the antenna used. Based on the above, the received electric field strength is written in the storage unit 26. In addition, when the antenna is switched during communication with another wireless communication device, the data writing processing unit 25 performs the switching after switching based on the source address and the antenna used after switching. The received electric field strength at the antenna being used is written into the storage unit 26.

  As a result, for example, table information as shown in FIG. 6 is stored in the storage unit 26. For example, when the antenna “1” (that is, the first antenna 11) is used for the wireless communication apparatus having the address “001”, “31” as the received electric field strength is changed to the antenna “2” (that is, the first antenna 11). When the second antenna 12) is used, “10” is written as the received electric field strength.

  Further, since there is no received field strength data when the antenna “1” or “2” is used for the wireless communication apparatus with the address “002”, this field is blank. Furthermore, when the antenna “2” is used for the wireless communication apparatus with the address “004”, “10” is written as the received electric field strength, but the case where the antenna “1” is used is written. Since there is no received field strength data, this area is blank.

  As described above, the wireless reception device 1 ′ is transmitted from the communication device and, based on the received frame, the first identification unit (the first identification unit) that identifies whether the transmission destination of the frame is the device itself. 1), and when the transmission destination of the frame is the own apparatus 1 ', an antenna (11.multidot.11) used for reception according to the reception state of the frame (reception state indicated by the received electric field strength). 12) is switched. Therefore, it is possible to obtain the same effect as that obtained by radio receiving apparatus 1 shown in the first embodiment. Further, the received electric field strength can be stored in the table of the storage unit 26 in correspondence with the address of the transmission source and the antenna.

  Note that the method of storing the received electric field intensity in the storage unit 26 using the table as described above is merely an example, and the present invention is not limited to this. As long as the data writing processing unit 25 is configured to write the frame transmission source and the received electric field strength (communication state) obtained by the antenna used for reception in association with the storage unit 26. .

  In addition, when the received electric field strength is already written in the storage unit 26, the overwriting process is performed to update the received electric field strength data stored in the storage unit 26. Further, when a new communication device joins the network to which the wireless reception device 1 ′ is subscribed and there is no address in the table, a new address is added.

  Next, a case where the first identification unit 17 ′ identifies that “the transmission destination of the frame is not the own apparatus” will be described.

  In this case, the first identification unit 17 ′ notifies the third identification unit 22 of information indicating that the transmission destination of the frame is not its own device. When receiving information indicating that the transmission destination of the frame is not its own device, the third identification unit 22 determines whether or not the frame created by the frame processing unit 15 includes data indicating grant of the transmission right of the frame. Identify

  In other words, in a network system in which a plurality of wireless communication devices and a central management device are connected via a communication network, where the central management device manages transmission rights in the network system, the communication network Thus, the communication device that can transmit data is a wireless communication device having a transmission right at that time. In such a network system, the central control apparatus transmits a frame (QoS-CF (Contention Free) -Poll frame) indicating transmission right grant to the wireless communication apparatus. For this reason, the third identification unit 22 is configured to identify whether or not the frame created by the frame processing unit 15 includes data indicating the granting of the transmission right of the frame.

  If the third identification unit 22 determines that data indicating the transmission right of the frame is included, the fourth identification unit 23 includes data indicating the transmission right of the frame. Notify that The fourth identification unit 23 identifies the wireless communication device to which the transmission right is granted based on the frame when receiving the notification that the data indicating the transmission right of the frame is included. To do. Specifically, as shown in the first embodiment, the address of the transmission destination is identified based on the field of Address 2 (transmission destination address) in the frame. Further, the fourth identification unit 23 sends the data of the identified address (hereinafter referred to as address data) to the data read processing unit 27.

  The data read processing unit 27 receives address data from the fourth identification unit 23. Then, the data read processing unit 27 reads the received electric field strength from the storage unit 26 based on the received address data. Specifically, the received electric field strength corresponding to the address is read for each antenna. For example, when the address is “001”, the received electric field intensity when using the antenna number “1” (that is, the first antenna 11) is 31, and the antenna number “2” (that is, the second antenna 12). The data read processing unit 27 reads that the received electric field strength is 10 when using (see FIG. 6).

  Then, the data read processing unit 27 notifies the antenna determination unit 28 of the information of the antenna number read from the storage unit 26 and the received electric field strength data corresponding to the antenna number for each antenna.

  The antenna determination unit 28 receives the information transmitted from the data read processing unit 27 to the antenna determination unit 28. Then, when the antenna determination unit 28 receives the above information, first, it is determined whether or not the received field strength data at each antenna regarding the wireless communication device that is the transmission source of the frame is stored for both antennas (11 and 12). to decide. The antenna determination unit 28 determines the magnitude of the received electric field strength between these antennas from the received electric field strength data at each antenna.

  Furthermore, the antenna determination unit 28 determines an antenna to be used in the future based on the determined result. Specifically, when the received electric field strength at the currently used antenna is larger than the received electric field strength at the other antennas, it is determined that the currently used antenna will be used in the future. On the other hand, when the received electric field strength at the currently used antenna is smaller than the received electric field strength at the other antenna, it is determined that another antenna will be used in the future.

  For example, when the address is “001”, the antenna determination unit 28 first determines the magnitude of the received electric field strength at the first antenna 11 and the received electric field strength at the second antenna 12. Here, since the received electric field strength at the first antenna 11 is larger than the received electric field strength at the second antenna 12, when the currently used antenna is the first antenna 11, the received electric field strength is currently used. The antenna (that is, the first antenna 11) is to be used in the future. On the other hand, when the currently used antenna is the second antenna 12, it is determined that another antenna (that is, the first antenna 11) will be used in the future.

  Further, the antenna determination unit 28 notifies the antenna switching unit 20 ′ of the antenna determined to be used in the future. When only the received electric field strength at one antenna is stored in the storage unit 26, or when no received electric field strength is stored in the storage unit 26, the antenna determining unit 28 includes the antenna switching unit. The process is terminated without performing the above notification to 20 '.

  When receiving the notification from the antenna determination unit 28, the antenna switching unit 20 ′ performs antenna switching processing in response to the notification. That is, when the notification from the antenna determination unit 28 is an antenna that is currently used, the antenna switching process is not performed, and when the notification is an antenna that is not currently used, the antenna switching process is performed. Do.

  As described above, the wireless reception device 1 ′ includes the storage unit (storage unit) 26 that stores the reception state (electric field reception intensity) of the frame addressed to itself at each antenna (11, 12) for each communication device. A third identification unit (third identification means) 22 for identifying whether or not the received frame includes data indicating the grant of the transmission right of the frame when the transmission destination of the frame is not its own device 1 ′; A fourth identification unit (fourth identification means) 23 for identifying a communication device to which a transmission right is granted based on the received frame, when the received frame includes data indicating transmission right grant; For the communication device to which the transmission right is given, the data reading processing unit (reading unit) 27 for reading the reception state of the frame addressed to the own device at each antenna (11, 12) from the storage unit 26, and the reading Based on the reception state, it is configured to include an antenna determining unit (antenna determining means) 28 for determining the antenna used for reception.

  According to the above configuration, when a frame whose transmission destination is not the own apparatus 1 ′ is received, the third identification unit 22 determines whether the received frame includes data indicating granting of the transmission right of the frame. Identified. When the received frame includes data indicating the transmission right, the fourth identification unit 23 identifies the communication device to which the transmission right is granted based on the received frame. Therefore, the third identification unit 22 and the fourth identification unit 23 can identify the communication device having the next transmission right.

  Moreover, the memory | storage part 26 has memorize | stored the reception state of the flame | frame addressed to the own apparatus in each antenna (11 * 12) for every communication apparatus. Then, the data reading processing unit 27 can read the reception state of the frame addressed to the own device at each antenna (11, 12) from the storage unit 26 for the communication device to which the transmission right is given. That is, the data reading processing unit 27 can read out the reception state from the storage unit 26 when each antenna (11, 12) is used for the next communication apparatus having the transmission right.

  Further, the antenna determination unit 28 determines an antenna for reception based on the read reception state. For example, the antenna having the best reception state may be determined as the antenna used for communication.

  Therefore, by switching the antennas (11, 12) used for communication in accordance with the above determination, it is possible to improve the frame reception state in the own apparatus 1 ′.

  In addition, when the transmission destination of the frame is the own device 1 ′, the wireless reception device 1 ′ associates the transmission source of the frame with the reception state at the antenna used for reception in the storage unit 26. A data writing processing unit (writing means) 25 for writing is provided.

  According to the above configuration, when the transmission destination of the frame is the own apparatus 1 ′, the data write processing unit 25 causes the storage unit 26 to communicate with the transmission source of the frame and the antenna used for reception. Written in association with the state.

  Accordingly, the reception state information can be stored in the storage unit 26. Therefore, in the subsequent antenna switching processing, the reception state information written by the data writing processing unit 25 can be used.

  Next, the flow of antenna switching processing in the radio receiving apparatus 1 ′ will be described based on the flowchart of FIG.

  First, radio waves (signals) are received by any of the antennas (11, 12) (S11). Here, one of the antennas is an antenna that has been used until immediately before receiving the radio wave. After S11, the received electric field strength calculation unit 21 ′ calculates the received electric field strength (S12). After S12, the signal demodulator 14 demodulates the signal (S13).

  After S13, the frame processing unit 15 performs frame processing based on the demodulated signal to create a frame (S14). After S14, the first identification unit 17 'identifies whether the transmission destination of the frame is the own apparatus based on the frame (S15).

  In S15, when the transmission destination of the frame is its own device (in the case of Yes), the data writing processing unit 25 obtains the storage unit 26 from the transmission source of the frame and the antenna used for communication. In association with the received electric field strength to be written. (S16). If the transmission destination of the frame is its own device, the second identification unit 18 further identifies whether or not the frame type is a QoS data frame (S17).

  In S17, when the frame type is not a QoS data frame (No), the process is terminated without performing the antenna switching process. On the other hand, when the frame type is a QoS data frame, the comparison unit 19 compares the received electric field strength calculated by the received electric field strength calculation unit 21 ′ with the predetermined threshold value. Specifically, it is determined whether or not the received electric field strength is smaller than a predetermined threshold (S18).

  In S18, when the received electric field strength is larger than the predetermined threshold (in the case of No), the process is terminated without performing the antenna switching process. On the other hand, when the received electric field strength is smaller than the predetermined threshold (in the case of Yes), the antenna switching unit 20 ′ performs antenna switching processing (S19). After S19, the process ends.

  On the other hand, in S15, when the transmission destination of the frame is not its own device (in the case of No), the third identification unit 22 includes data indicating granting of the transmission right of the frame in the frame created by the frame processing unit 15. It is determined whether or not. In other words, the third identifying unit 22 determines whether or not the frame created by the frame processing unit 15 is a frame (QoS-CF (Contention Free) -Poll frame) indicating transmission right grant (S20). .

  In S20, when the created frame is not a QoS-CF-Poll frame (in the case of No), the process ends. On the other hand, when the created frame is a QoS-CF-Poll frame in S20 (in the case of Yes), the fourth identification unit 23 determines the frame transmission source based on the frame created by the frame processing unit 15. A communication device is identified (S21).

  After S21, is the antenna determination unit 28 stored in the table of the storage unit 26, the received field strength data at each antenna regarding the wireless communication device that is the frame transmission source is stored for both antennas (11 and 12)? It is determined whether or not (S22).

  In S22, when the received electric field strength is not stored for both antennas (11, 12) (No), the process is terminated. On the other hand, when the received field strength is stored for both antennas (11, 12) in S22 above (in the case of Yes), the antenna determination unit 28 receives the received signal between these antennas from the received field strength data at each antenna. Determine the magnitude of the electric field strength. Specifically, it is determined whether the received electric field strength at the currently used antenna is smaller than the received electric field strength at the other antennas (S23).

  In S23, when the received electric field strength at the currently used antenna is larger than the received electric field strength at the other antennas (in the case of No), the antenna switching unit 20 ′ performs antenna switching processing. Without ending the process. On the other hand, in S23, when the received electric field strength at the currently used antenna is smaller than the received electric field strength at the other antennas (in the case of Yes), the antenna switching unit 20 ′ performs the antenna switching process. Perform (S19).

  Note that the step of calculating the received electric field intensity shown in S12 is not necessarily performed before the signal demodulating step shown in S13, and may be performed at least by the step shown in S16.

  Also in the present embodiment, the number of antennas is not limited to two as in the first embodiment.

  Also in the present embodiment, similarly to the first embodiment, the configuration of the wireless reception device 1 ′ may be a configuration that does not include the second identification unit 18.

  Similarly to the first embodiment, the frame processing unit 15 is provided with a frame error rate calculation unit for calculating a frame error rate, and the frame error rate calculated by the frame error rate calculation unit is compared with a predetermined threshold value. It is good also as a structure compared in the part 19. FIG.

  Further, the frame processing unit 15 is provided with a continuous error calculation unit for calculating the number of continuous errors in the frame, and the comparison unit 19 compares the number of continuous errors in the frame calculated by the continuous error calculation unit with a predetermined threshold. Also good.

  Further, the signal demodulator 14 may be provided with a bit error rate calculator that calculates the bit error rate, and the comparison unit 19 may compare the bit error rate calculated by the bit error rate calculator with a predetermined threshold value. .

  The signal demodulator 14 is provided with a signal-to-noise ratio calculator (signal-to-noise ratio calculator) for calculating a signal-to-noise ratio (SNR), and the signal-to-noise ratio calculated by the signal-to-noise ratio calculator The comparison unit 19 may compare the predetermined threshold value.

  Further, the signal demodulation unit 14 is provided with a modulation accuracy calculation unit (modulation accuracy calculation means) for calculating the modulation accuracy (EVM), and the modulation accuracy calculated by the modulation accuracy calculation unit is compared with a predetermined threshold by the comparison unit 19. It is good also as composition to do.

  Furthermore, as a configuration for determining whether to switch antennas using two or more of received electric field strength, frame error rate, number of consecutive frame errors, bit error rate, signal-to-noise ratio, and modulation accuracy Also good.

  When using the frame error rate, the number of consecutive frame errors, the bit error rate, the signal-to-noise ratio, and / or the modulation accuracy, these values are stored in a table similar to the received electric field strength. Use the configuration.

  Also, as shown in the first embodiment, the antenna used for reception may be switched only when the frame real-time requirement is high.

  Also in this embodiment, as shown in Embodiment 1, the antenna used for reception may be switched based on the frame processing result in the frame processing unit regardless of the transmission destination of the frame.

  Similarly to the first embodiment, the signal demodulation unit 14 is provided with the frame length calculation unit and the frame length determination unit. When the frame length is equal to or longer than a predetermined length, reception is performed according to the reception state of the frame. It can also be set as the structure which switches the antenna to be used.

  Similarly to the first embodiment, the signal demodulation unit 14 is provided with the modulation rate calculation unit and the modulation rate determination unit. When the modulation rate is equal to or higher than a predetermined rate, the antenna used for reception depends on the reception state of the frame. It is good also as a structure which switches.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  In addition, since the wireless communication device includes the wireless reception device (1 · 1 ′), the wireless communication device can obtain the effects of the wireless reception device described above.

  In addition, each part (except an antenna and a memory | storage part) and each process step of the radio | wireless receiver (1 * 1 ') of the said embodiment are memory | storage means, such as arithmetic means, such as CPU, ROM (Read Only Memory), RAM It can be realized by executing the program stored in the above and controlling input means such as a keyboard, output means such as a display, or communication means such as an interface circuit. Therefore, the computer having these means reads the recording medium storing the program and executes the program, thereby realizing various functions and various processes of the wireless reception device (1 · 1 ′) of the present embodiment. be able to. In addition, by recording the program on a removable recording medium, the various functions and various processes described above can be realized on an arbitrary computer.

  As this recording medium, a program medium such as a memory (not shown) such as a ROM may be used for processing by the microcomputer, or a program reader is provided as an external storage device (not shown). It may be a program medium that can be read by inserting a recording medium therein.

  In any case, the stored program is preferably configured to be accessed and executed by the microprocessor. Furthermore, it is preferable that the program is read out, and the read program is downloaded to a program storage area of the microcomputer and the program is executed. It is assumed that this download program is stored in advance in the main unit.

  The program medium is a recording medium configured to be separable from the main body, such as a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a flexible disk or a hard disk, or a disk such as a CD / MO / MD / DVD. Fixed disk system, card system such as IC card (including memory card), or semiconductor memory such as mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash ROM, etc. In particular, there are recording media that carry programs.

  Further, if the system configuration is capable of connecting to a communication network including the Internet, the recording medium is preferably a recording medium that fluidly carries the program so as to download the program from the communication network.

  Further, when the program is downloaded from the communication network as described above, it is preferable that the download program is stored in the main device in advance or installed from another recording medium.

  The present invention is applicable to mobile communication devices such as mobile phones and PDAs (Personal Digital Assistants) having communication functions, and other wireless communication devices.

It is a functional block diagram of the radio | wireless receiver which concerns on embodiment of this invention. It is the figure which showed the example of the format of the flame | frame which the said radio | wireless receiver receives. It is the flowchart which showed the flow of the antenna switching process in the said radio | wireless receiver. It is a functional block diagram of the radio | wireless receiver which concerns on other embodiment of this invention. It is the figure which showed the table where reception electric field strength is memorize | stored. It is the figure which showed the state by which the received electric field strength was written in the said table. It is the flowchart which showed the flow of the antenna switching process in the said radio | wireless receiver. It is a functional block diagram of the conventional radio | wireless receiving apparatus.

Explanation of symbols

1 '1' Wireless receiver 11 First antenna 12 Second antenna 13 Receiver 14 Signal demodulator 15 Frame processor 16 Upper processor 17/17 'First identification unit (first identification means)
18 2nd identification part (2nd identification means)
19 Comparison part (comparison means)
20.20 'Antenna switching part (antenna switching means)
21 · 21 ′ Received electric field strength calculating section
22 3rd identification part (3rd identification means)
23 4th identification part (4th identification means)
24 5th identification part 25 Data writing process part (writing means)
26 storage unit (storage means)
27 Data reading processor (reading means)
28 Antenna determining unit (antenna determining unit)

Claims (14)

In a radio receiving apparatus comprising a plurality of antennas and switching an antenna used for reception between the plurality of antennas,
Frame processing means for processing a frame transmitted and received from the communication device;
A radio receiving apparatus comprising: an antenna switching unit that switches an antenna used for reception based on at least a frame processing result in the frame processing unit. First identification means for identifying whether or not the transmission destination of the frame is its own device based on a frame processing result in the frame processing means;
The radio reception apparatus according to claim 1, wherein when the transmission destination of the frame is the own apparatus, the antenna switching unit switches an antenna used for reception according to a reception state of the frame. First identification means for identifying whether the transmission destination of the frame is its own device based on a frame processing result in the frame processing means;
Second identification means for identifying whether or not the type of the frame is a frame that requires real-time properties based on a frame processing result in the frame processing means;
When the transmission destination of the frame is its own apparatus, and the frame type is a frame that requires real-time property, the antenna switching means performs reception according to the reception state of the frame. The radio receiving apparatus according to claim 1, wherein an antenna to be used is switched. First identification means for identifying whether the transmission destination of the frame is its own device based on a frame processing result in the frame processing means;
Second identification means for identifying whether or not the type of the frame is a frame that requires real-time property based on a frame processing result in the frame processing means;
When the index indicating the degree of real-time request of the frame is set as the priority, priority identifying means for identifying the priority of the frame based on the frame processing result in the frame processing means;
Determination means for determining whether the priority identified by the priority identification means is higher than a predetermined degree;
When the transmission destination of the frame is its own device, and when the type of the frame is a frame that requires real-time properties, and when the priority is higher than a predetermined degree, The radio receiving apparatus according to claim 1, wherein the antenna switching means switches an antenna used for reception according to a reception state of the frame. Storage means for storing for each communication device the reception state of the frame addressed to itself at each antenna;
Third identification for identifying whether or not the received frame includes data indicating grant of a transmission right of the frame based on a frame processing result in the frame processing means when the transmission destination of the frame is not its own device Means,
A fourth identification unit that identifies a communication device to which a transmission right is granted based on a frame processing result in the frame processing unit when the received frame includes data indicating transmission right grant;
For the communication device to which the transmission right is granted, reading means for reading the reception state of the frame addressed to the own device at each antenna from the storage means;
The radio receiving apparatus according to any one of claims 2 to 4, further comprising an antenna determining unit that determines an antenna to be used for reception based on the read reception state.   When the transmission destination of the frame is its own apparatus, the storage unit includes a writing unit that writes the transmission source of the frame in association with the reception state at the antenna used for reception. Item 6. The wireless communication device according to Item 5. Frame length calculating means for calculating a frame length based on the received frame;
Frame length determination means for determining whether or not the calculated frame length is equal to or longer than a predetermined length;
The radio reception apparatus according to claim 1, wherein when the frame length is equal to or longer than a predetermined length, the antenna switching unit switches an antenna used for reception according to a reception state of the frame. A modulation rate calculating means for calculating a modulation rate based on the received frame;
Modulation speed determining means for determining whether the calculated modulation speed is equal to or higher than a predetermined speed;
2. The radio receiving apparatus according to claim 1, wherein when the modulation speed is equal to or higher than a predetermined speed, the antenna switching unit switches an antenna used for reception according to a reception state of the frame. A received electric field strength calculating means for calculating a received electric field strength based on the received frame;
Comparing means for comparing the calculated received electric field strength with a predetermined threshold,
The reception state is indicated by the reception electric field strength,
9. The radio receiving apparatus according to claim 2, wherein, when the received electric field strength is smaller than the predetermined threshold, the antenna switching unit switches an antenna used for reception. Modulation accuracy calculating means for calculating the modulation accuracy based on the received frame;
Comparing means for comparing the calculated modulation accuracy with a predetermined threshold,
The communication state is indicated by the modulation accuracy,
The radio reception apparatus according to any one of claims 2 to 8, wherein when the modulation accuracy is higher than the predetermined threshold, the antenna switching unit switches an antenna used for reception. A signal-to-noise ratio calculating means for calculating a signal-to-noise ratio based on the received frame;
Comparing means for comparing the calculated signal-to-noise ratio with a predetermined threshold,
The communication state is indicated by the signal-to-noise ratio,
The radio reception apparatus according to any one of claims 2 to 8, wherein when the signal-to-noise ratio is smaller than the predetermined threshold, the antenna switching unit switches an antenna used for reception. A bit error rate calculating means for calculating a bit error rate based on the received frame;
Comparing means for comparing the calculated bit error rate with a predetermined threshold,
The reception state is indicated by the bit error rate,
9. The radio reception apparatus according to claim 2, wherein when the bit error rate is higher than the predetermined threshold, the antenna switching unit switches an antenna used for reception. Frame error rate calculating means for calculating a frame error rate based on the received frame;
Comparing means for comparing the calculated frame error rate with a predetermined threshold,
The reception state is indicated by the frame error rate,
9. The radio reception apparatus according to claim 2, wherein when the frame error rate is higher than the predetermined threshold, the antenna switching unit switches an antenna used for reception. Based on the received frame, continuous error calculation means for calculating the number of continuous errors of the frame,
Comparing means for comparing the calculated number of consecutive errors of the frame with a predetermined threshold,
The reception state is indicated by the number of consecutive errors in the frame,
9. The radio reception apparatus according to claim 2, wherein when the number of consecutive errors in the frame is greater than the predetermined threshold, the antenna switching unit switches an antenna used for reception.

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