JP5380995B2 - Radio receiving apparatus and method - Google Patents

Description

  The present invention relates to a radio receiving apparatus and method for receiving data transmitted using a multicarrier transmission scheme.

  In recent years, short-range wireless communication, called PAN (Personal Area Network), can realize high-quality video and sound communication and large-volume data exchange between personal computers and AV devices. Wireless USB (Universal Serial Bus) Is attracting attention. The wireless USB employs the UWB (Ultra Wideband) system promoted by the WiMedia Alliance as a wireless communication system. UWB has low power consumption, but can perform high-speed communication far exceeding the popular 802.11a / b / g, so that it can improve the efficiency of communication in the office and the convenience of life. It is expected to be installed in various devices. In UWB, as shown in Fig. 1, the 3.1GHz to 10.6GHz band is divided into 14 bands as 1 band 528MHz band, and band # 1, band # 2, ..., band # 14 are numbered from the lower band. Is attached. Three bands are grouped and called a channel. Furthermore, when performing communication on channel # 1, depending on the hopping pattern, communication may be performed using only one band as shown in FIG. 2, or communication may be performed using three bands as shown in FIG. Can do.

  According to "MultiBand OFDM Physical Layer Specification Version 1.2" established by the WiMedia Alliance, a multiband OFDM signal has a bandwidth of 528 MHz and 128 subcarriers. Of these subcarriers, 6 are null subcarriers, 10 are guard subcarriers, and 12 are pilot subcarriers. Data is transmitted on the remaining 100 subcarriers. FIG. 4 shows the arrangement of each subcarrier in the frequency domain. Further, according to the specification, various transmission rates are defined by the modulation scheme, frequency domain spreading (FDS), and time domain spreading (TDS). FIG. 5 shows PHY parameters related to the transmission rate. As shown in FIG. 5, a DCM (Dual-carrier modulation) modulation method is employed as a modulation method when the transmission rate is 320 Mbps or higher. The DCM modulation method will be described.

  In the DCM modulation method, 200 bits are divided into 50 groups of 4 bits each. If each bit is b [i] (i∈ [0, 199]), the 4-bit group is b [g (k)], b [g (k) +1], b [g (k) +50]. , B [g (k) +51]. Here, k∈ [0, 49], and g (k) is g (k) = 2k when k∈ [0, 24], and g (k) when k∈ [25, 49]. = 2k + 50. This 4-bit group is mapped to two IQ planes (d [k], d [k + 50]). Here, d [i] (iε [0, 99]) is set, and d [0] is allocated to the data subcarrier having the lowest frequency and d [99] is allocated to the highest frequency. Here, the data subcarrier indicates a subcarrier for transmitting data. FIG. 6 shows two IQ planes (d [k], d [k + 50]). FIG. 7 shows an example of a coding table of the DCM modulation method. The two IQ planes shown in FIG. 6 are d [k], which is a low frequency subcarrier, and d [k + 50], which is a high frequency subcarrier, which are 50 data subcarriers apart, and the distance is 200 MHz. That's it. In general, when demodulating a DCM modulated signal, the I component of d [k] and d [k + 50] or the Q component of d [k] and d [k + 50] is demodulated in the same manner as QPSK demodulation. . The probability that the subcarriers of d [k], which is a low frequency subcarrier, and d [k + 50], which is a high frequency subcarrier, are deteriorated simultaneously by fading is lower. When the influence of fading on the subcarriers d [k], which is a low frequency subcarrier and d [k + 50], which is a high frequency subcarrier, is small, a frequency diversity effect is obtained.

  Further, even if demodulation is not performed using two subcarriers, 16QAM is performed using only one subcarrier of only d [k] that is a low frequency subcarrier or only d [k + 50] that is a high frequency subcarrier. Demodulation can be performed in the same manner as demodulation. A general demodulation method using two subcarriers has high resistance to frequency selective fading, but is good when the characteristics of either the low band or the high band are extremely deteriorated. There is a drawback that the characteristics of the subcarrier are also deteriorated. An example is shown below.

  FIG. 8 shows a reception spectrum of the wireless reception device when receiving in band 2. Since another wireless communication apparatus transmits and receives data in band 3 which is an adjacent band of band 2 on which the wireless communication apparatus is performing reception processing, a reception signal is also present in band 3. In this case, the received signal of the band 3 is large, and the shoulder of the received signal spectrum of the band 3 is affected by the signal spectrum of the band 2, which deteriorates the characteristics of the high frequency subcarriers of the band 2. In such a case, the DCM modulation signal can be demodulated by performing demodulation using only d [k] of the low frequency subcarrier. Conversely, if demodulation processing is performed using both the low-frequency subcarrier d [k] and the high-frequency subcarrier d [k + 50], reception is performed due to the influence of the high-frequency subcarrier d [k + 50] having poor characteristics. There is a problem that the characteristics deteriorate.

  As shown in FIG. 5, FDS is adopted when the transmission rate is 80 Mbps or less. The FDS will be described.

In FDS, the subcarrier d [i] (iε [0, 49]) modulated by the QPSK modulation method is used. Assuming that the data subcarrier after FDS is C [i] (i∈ [0, 99]), when k∈ [0, 49], C [k] = d [k] and k∈ [50 , 99], C [k] = d ^* [99−k] (where * indicates a conjugate complex number). That is, the same data is transmitted to two data subcarriers separated by 8.25 MHz to 462 MHz. In general, at the time of demodulation, demodulation processing is performed using the average of data subcarriers that transmitted two identical data apart. The probability that two subcarriers are deteriorated simultaneously due to fading is lower. When the influence of fading on the two subcarriers is small, a frequency diversity effect can be obtained. Of course, since the same data is transmitted, it is possible to demodulate only one of the subcarriers without using two data subcarriers.
JP 2008-124815 A

  In general, a demodulation method using two subcarriers has a high tolerance to frequency selective fading, but if one of the subcarrier characteristics is extremely deteriorated, a good subcarrier characteristic is also obtained. There is a drawback of making it worse. Even in the case of FDS, in order to demodulate the band 2 signal in the environment shown in FIG. 8 described above, it is better to perform demodulation using only the subcarriers on the low frequency side with respect to the center frequency. Characteristics are obtained. If demodulation processing is performed using two data subcarriers, there is a problem that reception characteristics deteriorate due to the influence of high frequency subcarriers with poor characteristics.

  On the other hand, in many cases, a wireless network access point is installed in an office or public, and a dedicated network administrator sets an appropriate channel or location in advance so as not to cause radio wave interference with neighboring access points. However, in short-distance wireless communication such as PAN, a dedicated network administrator is not set up, so channel setting in consideration of radio wave interference with neighboring wireless devices cannot be performed. For this reason, in wireless USB, the occurrence of radio wave interference is unavoidable, and a wireless receiver that is resistant to radio wave interference is required.

  Determine whether the interference signal wave from another device is on the low frequency side or the high frequency side with respect to the center frequency of the signal transmission band of its own station, and based on the determination result, the band side where the interference signal exists A method is disclosed in which transmission subcarriers corresponding to half of the transmission signal band of the own station are deleted and transmitted (for example, see Patent Document 1). In this method, if the transmitting-side radio communication apparatus does not notify the receiving-side radio communication apparatus that the transmission subcarrier is deleted before deleting the transmission subcarrier, the reception performance is greatly deteriorated. . Therefore, it takes time to notify, and it takes time to deal with the interference signal. Therefore, it is desirable that the number and arrangement of subcarriers for transmitting data transmitted from the wireless communication device are not changed. Further, since the influence of interference from UWB communication that communicates in the adjacent band differs between the wireless communication device on the transmission side and the wireless communication device on the reception side, interference from the adjacent band in the wireless communication device on the reception side. There is a problem that it cannot be handled properly.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a radio reception apparatus and method that can improve tolerance to interference from adjacent bands.

In order to solve the above problem, the wireless receiving device
A wireless reception device in a wireless communication system that transmits and receives data using a multicarrier transmission scheme in which frequency bands including a plurality of subcarriers are arranged at predetermined frequency intervals,
Each subcarrier for transmitting data transmitted and received in the wireless communication system is modulated by a predetermined modulation method,
An adjacent frequency band communication status detection unit that detects a received signal strength of data from a radio communication apparatus that transmits data using a frequency band adjacent to a frequency band used for data reception by the wireless reception apparatus; ,
Based on the received signal strength of the data from the radio communication device detected by the adjacent frequency band communication status detection unit, the data modulated by the predetermined modulation method is reduced so as to reduce interference from the radio communication device. A demodulated data subcarrier determining unit that determines the number of subcarriers in the frequency band used for the reception used in the demodulation process;
A demodulation unit that performs demodulation processing using the subcarriers used for the demodulation processing determined in the demodulated data / subcarrier determination unit, and
The demodulated data / subcarrier determination unit includes:
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication apparatus is adjacent to the high frequency side of the frequency band used for reception Only the subcarrier on the low frequency side is determined as the subcarrier used for the demodulation process,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication device is adjacent to the low frequency side of the frequency band used for reception Only the subcarriers on the high frequency side are determined as the subcarriers used for the demodulation process.

This method
A method in a wireless reception device of a wireless communication system for transmitting and receiving data using a multicarrier transmission method in which frequency bands including a plurality of subcarriers are arranged at predetermined frequency intervals,
Subcarriers transmitted and received in the wireless communication system are modulated by a predetermined modulation scheme,
Detecting a received signal strength of data from a wireless communication device that transmits data using a frequency band adjacent to a frequency band used for data reception by the wireless reception device; and
Based on the received signal strength data from a wireless communication device detected in the step of detecting the received signal strength, so as to reduce interference from the wireless communications device, the data modulated by the predetermined modulation scheme Determining the number of subcarriers in the frequency band used for the reception used for demodulation processing;
Performing demodulation processing using the subcarriers used for demodulation processing determined in the step of determining the number of subcarriers in the frequency band used for the reception, and
Determining the number of subcarriers in the frequency band used for the reception,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication apparatus is adjacent to the high frequency side of the frequency band used for reception Only the subcarrier on the low frequency side is determined as the subcarrier used for the demodulation process,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication device is adjacent to the low frequency side of the frequency band used for reception Only the subcarriers on the high frequency side are determined as the subcarriers used for the demodulation process.

  According to the disclosed radio reception apparatus and method, it is possible to improve resistance to interference from adjacent bands.

Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  Hereinafter, the radio receiving apparatus according to the present embodiment will be described with reference to FIG.

  The wireless receiving device 100 according to the present embodiment is included in a wireless communication device, and wireless USB is applied as a communication technology for wireless connection. Wireless USB uses spread spectrum technology based on UWB (Ultra wideband). UWB is a wireless technology that uses a very wide band of several GHz.

  FIG. 9 shows a configuration example of a wireless reception device that performs wireless communication by wireless USB. FIG. 9 shows only the DCM demodulation function unit related to the present embodiment, and the function units related to reception and transmission are omitted.

  The wireless reception device 100 includes an antenna 102, an RF unit 104 that receives an RF signal from the antenna 102, an ADC (Analog to Digital Converter) unit 106, a baseband reception unit 108, a DCM demodulation unit 110, and demodulated data. -It has the subcarrier determination part 112 and the adjacent frequency band communication condition detection part 114.

  The RF unit 104 receives a DCM modulated signal transmitted from a wireless transmission device included in another wireless communication device via the antenna 102. For example, the wireless transmission device transmits data using a multicarrier transmission scheme in which a plurality of subcarriers are arranged at predetermined frequency intervals.

  The RF unit 104 amplifies the DCM modulation signal, generates an I signal and a Q signal, performs gain adjustment, and inputs the signal to the ADC 106.

  The ADC 106 converts the input I signal and Q signal subjected to gain adjustment to digital signals, and inputs the I signal and Q signal converted to the digital signals to the baseband receiving unit 108.

  The adjacent frequency band communication status detection unit 114 detects another radio communication apparatus that transmits and / or receives data using a frequency band close to the frequency band used by the radio reception apparatus 100. Then, the adjacent frequency band communication status detection unit 114 monitors the communication status of the wireless communication device when the other wireless communication device exists. From the viewpoint of detecting other wireless communication devices having a large influence on the wireless communication device 100, the adjacent frequency band communication status detection unit 114 uses a frequency band adjacent to the frequency band used by the wireless reception device 100. It is preferable to detect other wireless communication devices that transmit data. The adjacent frequency band communication status detection unit 114 inputs the communication status information of other wireless communication devices to the demodulated data / subcarrier determination unit 112. For example, the adjacent frequency band communication status detection unit 114 may input information transmitted by another wireless communication device to the demodulated data / subcarrier determination unit 112.

  Demodulated data / subcarrier determining section 112 determines a data subcarrier to be used for demodulation processing in DCM demodulating section 110 based on the input communication status of another wireless communication apparatus. For example, the demodulated data / subcarrier determination unit 112 is a subcarrier (hereinafter referred to as a data subcarrier) that transmits data used for demodulation processing by the DCM demodulation unit 110 based on the input communication status of another wireless communication device. May be determined. Data is mapped to the data subcarrier. The demodulated data / subcarrier determining unit 112 inputs information indicating the determined data / subcarrier to the DCM demodulating unit 110.

  The DCM demodulator 110 performs a demodulation process on the DCM modulated signal according to the data subcarrier input by the demodulated data subcarrier determiner 112. In this way, it can be applied when the transmission rate is 320 Mbps or more.

  In FIG. 9, the demodulated data / subcarrier determining unit 112 and the adjacent frequency band communication status detecting unit 114 are provided outside the baseband receiving unit 108. The detection unit 114 may be included in the baseband reception unit 108, or may be included in the DCM demodulation unit 110.

  The operation of the radio receiving apparatus 100 according to the present embodiment will be described with reference to FIG.

  The DCM modulated signal transmitted by the wireless transmission device is received by the RF unit 104 via the antenna 102 (step S1002). The RF unit 104 amplifies the DCM modulation signal, generates an I signal and a Q signal, performs gain adjustment, and inputs the signal to the ADC 106. The ADC 106 converts the input I signal and Q signal subjected to gain adjustment to digital signals, and inputs the I signal and Q signal converted to the digital signals to the baseband receiving unit 108.

  On the other hand, the adjacent frequency band communication status detection unit 114 detects another wireless communication device that transmits and / or receives data using the adjacent frequency band (step S1004).

  When the information indicating that there is no other wireless communication device that transmits and / or receives data using the adjacent frequency band is output from the adjacent frequency band communication status detection unit 114 (step S1004: YES). The demodulated data / subcarrier determining unit 112 determines to perform demodulation using both the data / subcarriers of the subcarriers d [k] and d [k + 50] (kε [0, 49]) (step S1006). Therefore, demodulated data subcarrier determining section 112 determines all data subcarriers as data subcarriers used for demodulation.

  When the adjacent frequency band communication status detection unit 114 outputs information indicating that there is another wireless communication device that transmits data using the adjacent frequency band (step S1004: NO), the demodulated data sub The carrier determination unit 112 determines whether the adjacent frequency band in which another wireless communication apparatus transmits data is a high frequency (step S1008). Here, it may be determined whether an adjacent frequency band in which another wireless communication apparatus transmits data is a low frequency band.

  When the adjacent frequency band in which another wireless communication apparatus transmits data is higher than the frequency band used for reception by the wireless reception apparatus, the demodulation data / subcarrier determination unit 112 Information indicating that there is another wireless communication device that transmits data using adjacent frequency bands in the band is input. When information indicating that there is another wireless communication device that transmits data using a high frequency adjacent frequency band is output (step S1008: YES), the demodulated data / subcarrier determining unit 112 It is determined that the reception characteristics of the data subcarriers in the region are greatly deteriorated, and d [k + 50 in the high region among the data subcarriers of d [k] and d [k + 50] (kε [0, 49]). ] Is not used for the DCM demodulation process, and it is determined that the demodulation process is performed using only the d [k] subcarriers in the low band (step S1010). Therefore, the demodulated data subcarrier determination unit 112 determines 50 low frequency data subcarriers as data subcarriers used for demodulation.

  On the other hand, when the adjacent frequency band in which another wireless communication apparatus transmits data is lower than the frequency band used for reception by the wireless reception apparatus, the demodulated data subcarrier determination unit 112 includes Information indicating that there is another wireless communication device that transmits data using the adjacent low frequency band is input. When information indicating that there is another wireless communication apparatus that transmits data using the adjacent low frequency band is output (step S1008: NO), the demodulated data / subcarrier determining unit 112 is It is determined that the reception characteristics of the data subcarriers in the region are greatly deteriorated, and d [k] in the lower region among the data subcarriers of d [k] and d [k + 50] (kε [0, 49]). ] Is not used in the DCM demodulation process, and it is determined that the demodulation process is performed using only the d [k + 50] subcarrier in the high band (step S1012). Therefore, the demodulated data subcarrier determining unit 112 determines 50 high frequency data subcarriers as data subcarriers used for demodulation.

  The DCM demodulation unit 110 performs DCM demodulation using the data subcarriers used for demodulation determined by the demodulation data / subcarrier determination unit 112.

According to the present embodiment, in a wireless communication system that transmits and / or receives data using a signal modulated by the DCM modulation method, the number and arrangement of subcarriers used for data to be transmitted are changed in the wireless transmission device. Without using the data subcarrier used in the DCM demodulation processing depending on the communication status of other wireless communication devices that transmit data using the frequency band adjacent to the frequency band with which the wireless reception device communicates. To decide. By doing so, it is possible to determine data subcarriers used for demodulation processing, and it is possible to increase resistance to interference from adjacent bands.
(Modification (Part 1))
A radio reception apparatus 100 according to this modification will be described with reference to FIG.

  The radio receiving apparatus 100 according to this modification includes a QPSK / FDS demodulator 116 instead of the DCM demodulator 110 in the radio receiver according to the above-described embodiment. In this way, the present invention can be applied when the transmission rate is 80 Mbps or less.

  FIG. 11 shows a configuration example of a wireless reception apparatus that performs wireless communication by wireless USB. FIG. 11 shows only the QPSK / FDS demodulation function unit related to the present embodiment, and omits the function units related to reception and transmission.

  The radio receiving apparatus 100 includes an antenna 102, an RF unit 104 that receives an RF signal from the antenna 102, an ADC unit 106, a baseband receiving unit 108, a QPSK / FDS demodulating unit 116, and a demodulation data / subcarrier determination. Unit 112 and adjacent frequency band communication status detection unit 114.

  The RF unit 104 receives a modulated signal (hereinafter referred to as a QPSK / FDS modulated signal) that is modulated by the QPSK modulation scheme transmitted by the wireless transmission apparatus and is transmitted by applying FDS via the antenna 102. For example, the wireless transmission device transmits data using a multicarrier transmission scheme in which a plurality of subcarriers are arranged at predetermined frequency intervals.

  The RF unit 104 amplifies the QPSK / FDS modulation signal, generates an I signal and a Q signal, performs gain adjustment, and inputs the signal to the ADC 106.

  The ADC 106 converts the input I signal and Q signal subjected to gain adjustment to digital signals, and inputs the I signal and Q signal converted to the digital signals to the baseband receiving unit 108.

  The adjacent frequency band communication status detection unit 114 detects another wireless communication device that transmits and / or receives data using a frequency band close to the frequency band used by the wireless communication device 100. Then, the adjacent frequency band communication status detection unit 114 monitors the communication status of the wireless communication device when the other wireless communication device exists. From the viewpoint of detecting other wireless communication devices having a large influence on the wireless communication device 100, the adjacent frequency band communication status detection unit 114 uses a frequency band adjacent to the frequency band used by the wireless communication device 100. It is preferable to detect other wireless communication devices that transmit data. The adjacent frequency band communication status detection unit 114 inputs the communication status information of other wireless communication devices to the demodulated data / subcarrier determination unit 112. For example, the adjacent frequency band communication status detection unit 114 may input information transmitted by another wireless communication device to the demodulated data / subcarrier determination unit 112.

  Demodulated data / subcarrier determining section 112 determines a data subcarrier to be used for demodulation processing by QPSK / FDS demodulating section 116 based on the input communication status of another wireless communication apparatus. For example, the demodulated data / subcarrier determining unit 112 determines the number of data subcarriers to be used in the demodulation process by the QPSK / FDS demodulating unit 116 based on the input communication status of another wireless communication apparatus. Also good. Demodulated data / subcarrier determining section 112 inputs information indicating the determined number of data subcarriers to QPSK / FDS demodulating section 116.

  The QPSK / FDS demodulator 116 demodulates the QPSK / FDS modulated signal according to the number of data subcarriers input from the demodulated data / subcarrier determiner 112.

  In FIG. 11, the demodulated data / subcarrier determination unit 112 and the adjacent frequency band communication status detection unit 114 are provided outside the baseband reception unit 108. The detection unit 114 may be provided in the baseband reception unit 108, or may be provided in the QPSK / FDS demodulation unit 116.

  An operation of the wireless reception device 100 according to the present embodiment will be described.

  The operation of the wireless reception device 100 is different from the operation described with reference to FIG. 10 in steps S1002, S1006, S1010, and S1012.

  In step S1002, a modulated signal that is modulated by the QPSK modulation scheme transmitted by the wireless transmission device and is transmitted by applying FDS is received.

  In steps S1006, S1010, and S1012, the QPSK / FDS demodulator 116 demodulates the QPSK / FDS modulated signal in accordance with (using) the data subcarrier input by the demodulated data subcarrier determiner 112.

  In this modification, a case has been described in which a modulated signal that has been modulated by a QPSK modulation scheme transmitted by a wireless transmission device and demodulated by applying FDS is demodulated, but is modulated by a QPSK modulation scheme transmitted by a wireless transmission device. The present invention can also be applied to the case of demodulating a modulated signal transmitted by applying TDS.

According to this modification, in a wireless communication system that transmits and / or receives data using a signal to which frequency domain spreading is applied, the number and arrangement of subcarriers used for data to be transmitted are changed in the wireless transmission device. Without using the frequency domain spread demodulation processing depending on the communication status of other wireless communication devices that transmit data using a frequency band adjacent to the frequency band with which the wireless reception device communicates. Determine the number of subcarriers. By doing in this way, the tolerance with respect to the interference from an adjacent band can be made high.
(Modification (Part 2))
This modification will be described with reference to FIG.

  FIG. 12 shows a reception spectrum of the wireless reception device 100 when receiving in band 2.

  FIG. 12A shows a situation in which another wireless communication device transmits and receives data with high reception intensity in band 3 which is a band adjacent to the band used by the wireless reception device 100. In FIG. 12A, a large received signal exists in band 3. In such a case, the adjacent frequency band communication status detection unit 114 transmits other data to the demodulated data / subcarrier determination unit 112 using the frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that the received signal strength of data from the wireless communication device is high is output.

  FIG. 12B shows a situation in which another wireless communication device transmits and receives data with a relatively low reception intensity in band 3 which is a band adjacent to the band used by wireless reception device 100. It is. In FIG. 12B, a relatively small received signal exists in band 3. In such a case, the adjacent frequency band communication status detection unit 114 transmits other data to the demodulated data / subcarrier determination unit 112 using the frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that the received signal strength of data from the wireless communication device is small is output.

  FIG. 12C shows a situation in which no other wireless communication device is communicating in a band adjacent to the band used by the wireless reception device 100. In such a case, the adjacent frequency band communication status detection unit 114 transmits other data to the demodulated data / subcarrier determination unit 112 using the frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that there is no data reception signal from the wireless communication device is output.

  When performing communication in the environment shown in FIG. 12, in the wireless reception device 100, the adjacent frequency band communication status detection unit 114 inputs the information as described above to the demodulated data / subcarrier determination unit 112. Demodulated data / subcarrier determining section 112 determines a subcarrier to be demodulated. Radio receiving apparatus 100 performs demodulation processing using each data subcarrier as shown in FIG. In FIG. 13, a square indicates a subcarrier, and a number indicated in the square indicates a subcarrier number.

  When performing communication in the environment illustrated in FIG. 12A, the adjacent frequency band communication status detection unit 114 transmits data using a frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that the received signal strength of data from the wireless communication apparatus is large is input to the demodulated data / subcarrier determining unit 112. The demodulated data / subcarrier determining unit 112 has a large deterioration in reception characteristics due to interference from the band 3, and therefore, as shown in FIG. 13A, d [k] and d [k + 50] (kε [0, 49). ]) Of the data subcarriers of d] [k + 50] in the high frequency band are not used for the DCM demodulation process, and only the d [k] data subcarriers are used for the demodulation process. decide. In FIG. 13A, black squares indicate subcarriers used for demodulation, and white squares indicate subcarriers not used for demodulation. In this case, the demodulated data subcarrier determining unit 112 determines 50 low frequency data subcarriers as demodulated data subcarriers.

  Also, the demodulated data / subcarrier determining unit 112, when reception characteristics are greatly deteriorated due to interference from band 1, determines the data subs of d [k] and d [k + 50] (k∈ [0, 49]). Of the carriers, the data subcarrier of d [k] in the low band is not used for the DCM demodulation process, but may be determined to perform the demodulation process using only the data subcarrier of d [k + 50]. Good.

  When performing communication in the environment illustrated in FIG. 12B, the adjacent frequency band communication status detection unit 114 transmits data using a frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that the received signal strength of data from the wireless communication device is small is input to the demodulated data / subcarrier determining unit 112. The demodulated data subcarrier determining unit 112 has a relatively small deterioration in reception characteristics due to interference from adjacent bands, and therefore, as shown in FIG. 13B, data subcarriers d [0] to d [74]. Is used for the DCM demodulation process and is determined to be demodulated. That is, the demodulated data / subcarrier determination unit 112 demodulates d [0] to d [24] and d [50] to d [74] using two data subcarriers in the same manner as in QPSK demodulation. . The demodulated data / subcarrier determining unit 112 uses one data subcarrier for d [25] to d [49] and performs demodulation in the same manner as in 16QAM demodulation. In FIG. 13B, black squares indicate subcarriers that are demodulated using one data subcarrier, and thick white squares indicate subcarriers that are not used for demodulation. The other squares indicate subcarriers that are demodulated using two data subcarriers. In this case, the demodulated data subcarrier determining unit 112 determines data subcarriers excluding 25 high frequencies as demodulated data subcarriers.

  When performing communication in the environment illustrated in FIG. 12C, the adjacent frequency band communication status detection unit 114 transmits data using a frequency band adjacent to the frequency band used by the wireless reception device 100. Information indicating that there is no data reception signal from the wireless communication apparatus is input to the demodulated data / subcarrier determination unit 112. Since there is no interference from the adjacent band, the demodulated data / subcarrier determining unit 112 has the data d [k] and d [k + 50] (k∈ [0, 49]) as shown in FIG. It is determined that demodulation processing is performed using both subcarriers. In FIG. 13C, white squares indicate subcarriers that are demodulated using two data subcarriers. In this case, demodulated data subcarrier determining section 112 determines all data subcarriers as demodulated data subcarriers.

  The number of data subcarriers used in the demodulation process shown in FIG. 13 is an example. The value may be changed to an appropriate value due to the influence of interference from adjacent bands or the influence of fading. By doing in this way, the tolerance with respect to the interference from an adjacent band can be improved, obtaining the frequency diversity effect more.

  This modification may be applied to the demodulation processing of the DCM modulated signal transmitted by the wireless transmission device, or is modulated by the QPSK modulation method transmitted by the wireless transmission device and transmitted by applying the FDS. The present invention may be applied to the demodulation process. Moreover, you may apply to the demodulation process of the modulation | alteration signal modulated with the other modulation system transmitted by the wireless transmitter.

  According to this modification, the number of data subcarriers used for demodulation processing can be determined finely, and the tolerance to interference from adjacent bands can be increased while obtaining the frequency diversity effect.

  According to this embodiment, based on the communication status of other wireless communication devices that transmit data using adjacent frequency bands, the number of subcarriers and the arrangement of transmitted data are not changed, and demodulation processing is performed. By determining the number of data subcarriers to be used, resistance against interference from adjacent bands can be increased.

  Although the present invention has been described above with reference to specific embodiments and modifications, these are merely examples, and those skilled in the art will understand various modifications, modifications, alternatives, substitutions, and the like. I will. Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The division of examples, modifications, or items is not essential to the present invention, and the matters described in two or more examples or items may be used in combination as necessary. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be realized by hardware, software, or a combination thereof. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

It is explanatory drawing which shows the band structure of MultiBand-OFDM. It is explanatory drawing which shows an example of the transmission method of the symbol in MultiBand-OFDM. It is explanatory drawing which shows an example of the transmission method of the symbol in MultiBand-OFDM. It is explanatory drawing which shows arrangement | positioning in the frequency domain of each subcarrier. It is explanatory drawing which shows the PHY parameter regarding a transmission rate. It is explanatory drawing which shows IQ plane. It is explanatory drawing which shows an example of the encoding table of a DCM modulation system. It is explanatory drawing which shows an example of the frequency spectrum detected in a radio | wireless receiver. It is a functional block diagram which shows the radio | wireless receiver which concerns on one Example. It is a flowchart which shows operation | movement of the radio | wireless receiver which concerns on one Example. It is a functional block diagram which shows the radio | wireless receiver which concerns on one Example. It is explanatory drawing which shows an example of the frequency spectrum detected in a radio | wireless receiver. It is explanatory drawing which shows an example of the subcarrier used for a demodulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Radio | wireless receiver 102 Antenna 104 RF part 106 ADC (Analog to Digital Converter) part 108 Baseband receiving part 110 DCM (Dual-carrier modulation) demodulation part 112 Demodulated data subcarrier determination part 114 Adjacent frequency band communication condition detection part 116 QPSK / FDS demodulator

Claims (6)

A wireless reception device in a wireless communication system that transmits and receives data using a multicarrier transmission scheme in which frequency bands including a plurality of subcarriers are arranged at predetermined frequency intervals,
Each subcarrier for transmitting data transmitted and received in the wireless communication system is modulated by a predetermined modulation method,
An adjacent frequency band communication status detection unit that detects a received signal strength of data from a radio communication apparatus that transmits data using a frequency band adjacent to a frequency band used for data reception by the wireless reception apparatus; ,
Based on the received signal strength of the data from the radio communication device detected by the adjacent frequency band communication status detection unit, the data modulated by the predetermined modulation method is reduced so as to reduce interference from the radio communication device. A demodulated data subcarrier determining unit that determines the number of subcarriers in the frequency band used for the reception used in the demodulation process;
A demodulation unit that performs demodulation processing using the subcarriers used for the demodulation processing determined in the demodulated data / subcarrier determination unit, and
The demodulated data / subcarrier determination unit includes:
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication apparatus is adjacent to the high frequency side of the frequency band used for reception Only the subcarrier on the low frequency side is determined as the subcarrier used for the demodulation process,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication device is adjacent to the low frequency side of the frequency band used for reception Only the high frequency side subcarrier is determined as a subcarrier used for the demodulation processing. The wireless receiver according to claim 1,
Subcarriers transmitted and received in the wireless communication system are modulated by a DCM modulation scheme,
The radio receiver according to claim 1, wherein the demodulator performs demodulation processing on a signal modulated by a DCM modulation method. The wireless receiver according to claim 1,
Subcarriers transmitted and received in the wireless communication system are modulated by a QPSK modulation method, frequency domain spreading is applied,
The radio receiving apparatus, wherein the demodulating section performs demodulation processing on a signal modulated by a QPSK modulation method and applied with frequency domain spreading. The radio reception apparatus according to any one of claims 1 to 3,
The adjacent frequency band communication status detection unit detects a communication status of a radio communication device that transmits data using a frequency band adjacent to a frequency band used by the radio reception device for data reception. A wireless receiving device. In the radio | wireless receiver of any one of Claim 1 thru | or 4 ,
The radio reception apparatus characterized in that the number of subcarriers transmitted in the radio communication system is not changed. A method in a wireless reception device of a wireless communication system for transmitting and receiving data using a multicarrier transmission method in which frequency bands including a plurality of subcarriers are arranged at predetermined frequency intervals,
Subcarriers transmitted and received in the wireless communication system are modulated by a predetermined modulation scheme,
Detecting a received signal strength of data from a wireless communication device that transmits data using a frequency band adjacent to a frequency band used for data reception by the wireless reception device; and
Based on the received signal strength data from a wireless communication device detected in the step of detecting the received signal strength, so as to reduce interference from the wireless communications device, the data modulated by the predetermined modulation scheme Determining the number of subcarriers in the frequency band used for the reception used for demodulation processing;
Performing demodulation processing using the subcarriers used for demodulation processing determined in the step of determining the number of subcarriers in the frequency band used for the reception, and
Determining the number of subcarriers in the frequency band used for the reception,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication apparatus is adjacent to the high frequency side of the frequency band used for reception Only the subcarrier on the low frequency side is determined as the subcarrier used for the demodulation process,
Among the plurality of subcarriers included in the frequency band used for reception when the frequency band used by the wireless communication device is adjacent to the low frequency side of the frequency band used for reception A method of determining only a subcarrier on a high frequency side as a subcarrier used for the demodulation processing.

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