JP4633782B2 - Wireless base station equipment - Google Patents

Description

  The present invention relates to a radio base station apparatus of a radio communication system using an Orthogonal Frequency Division Multiplexing (OFDM) system, and more particularly to a directional transmission / reception apparatus using an array antenna.

  Conventionally, a communication method using OFDM is widely known. In addition, adaptive array antenna technology is being studied for the purpose of increasing traffic capacity, expanding communication areas, suppressing interference, and the like. And the application of the adaptive array antenna technology in this OFDM system is attracting attention, and some are disclosed. For example, there is Patent Document 1 as one of them. In the disclosed example of this publication, the transmission / reception weight is calculated based on the frequency interval of the OFDM subcarrier and the antenna element interval of the array antenna, and the directional transmission / reception is performed by weighting each subcarrier.

JP-A-11-205026

  In the prior art according to the above disclosed example, it is possible to eliminate a directional beam pattern shift that occurs at subcarrier frequency intervals by setting a transmission weight and a reception weight for each subcarrier. However, when an amplitude deviation or a phase deviation occurs between the transmission / reception branches, the formed beam pattern is shifted from the desired beam pattern. Each transmission / reception branch is composed of many analog elements in the radio frequency circuit section. In these analog elements, the characteristics vary due to individual differences of the elements, and the characteristics fluctuate due to the ambient temperature and the passage of time. Due to such characteristics of the analog element, an amplitude / phase deviation occurs between the transmission / reception branches. In particular, in a wideband signal such as an OFDM signal, frequency characteristics may occur in the amplitude / phase deviation between the branches, and in this case, the beam pattern is shifted for each subcarrier frequency.

  The present invention solves such a problem, and when an amplitude phase deviation occurs between each branch of an array antenna, especially when the amplitude / phase deviation has a frequency characteristic, a desired directional beam is provided. An object of the present invention is to provide a radio base station apparatus that can form a pattern.

  In the present invention, a correction value for correcting the characteristics of the radio circuit unit in each transmission / reception branch of the array antenna is stored, and the calculated transmission / reception weight is corrected by the correction value, thereby forming a desired transmission / reception beam pattern. To do. At this time, a correction value can be calculated for each subcarrier of the OFDM signal.

  In the present invention, the amplitude / phase deviation between the branches generated from the variation in the characteristics of the radio circuit section in each transmission / reception branch of the array antenna is detected, and a correction value for correcting this deviation is calculated and stored. At this time, by detecting each subcarrier of the OFDM signal, a correction value can be calculated for each subcarrier. And, by correcting the transmission / reception weight using the correction value and weighting the signal, a desired beam pattern can be formed even when there is an amplitude / phase deviation between the branches, and good communication is possible. It becomes.

  As described above, according to the present invention, in a transmitting apparatus that transmits an OFDM signal directionally using an array antenna, the amplitude / phase deviation generated between transmission branches is detected for each subcarrier and has a correction value. The transmission weight can be corrected, and the beam pattern deviation caused by the amplitude / phase deviation between the transmission branches and the frequency characteristics of these deviations can be brought close to the desired beam pattern. In addition, by detecting a correction matrix for correcting coupling between antenna elements for each subcarrier, it is possible to perform coupling correction between antenna elements within the signal bandwidth and obtain a desired beam pattern, enabling good communication. The advantageous effect of being can be obtained.

  According to the first aspect of the present invention, there is provided a transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal, and a transmission correction value for storing a correction value for correcting the transmission weight. A memory unit, and a transmission weight correction unit that corrects the transmission weight with the correction value. The transmission weight calculation unit divides the signal bandwidth of the OFDM signal into a plurality of bands, One transmission weight is calculated for each of a plurality of subcarriers for each band, and the transmission weight correction unit uses the correction value for subcarriers existing in the band in which the transmission weight is calculated. The transmission weight is corrected, and when the OFDM signal is directionally transmitted using an array antenna, the transmission weight is corrected by the correction value. When transmitting beamforming, set the transmission weight is performed at each divided band in the OFDM signal bandwidth, compensation has the effect of performing for each subcarrier of the OFDM signal.

  The invention according to claim 2 of the present invention is a transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal, and a transmission correction value for storing a correction value for correcting the transmission weight. A memory unit, and a transmission weight correction unit that corrects the transmission weight with the correction value. The transmission correction value memory unit divides the signal bandwidth of the OFDM signal into a plurality of bands, One correction value is stored for each of the bands for a plurality of subcarriers existing in the, and the transmission weight is corrected by the correction value when OFDM signals are directionally transmitted using an array antenna. When performing transmission beam forming, the correction value has an effect of correcting the amplitude deviation and phase deviation between the transmission branches for each divided band within the OFDM signal bandwidth.

  The invention according to claim 3 of the present invention is a transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal, and a transmission correction value for storing a correction value for correcting the transmission weight. A memory unit, and a transmission weight correction unit that corrects the transmission weight with the correction value. The transmission correction value memory unit divides the signal bandwidth of the OFDM signal into a plurality of bands, The number of correction values smaller than the number of subcarriers present in the band is stored for each of the plurality of subcarriers in the band, and an OFDM signal is transmitted using an array antenna. When performing transmission beam formation by correcting the transmission weight with a correction value, the correction value indicates the amplitude deviation and phase deviation between the transmission branches within the OFDM signal bandwidth. An effect that is a value corrected for each divided band.

  The invention according to claim 9 of the present invention is a reception weight calculation unit for calculating a reception weight for directivity reception using an OFDM signal, and a reception correction value for storing a correction value for correcting the reception weight. A memory unit, and a reception weight correction unit that corrects the reception weight with the correction value. The reception weight calculation unit divides the signal bandwidth of the OFDM signal into a plurality of bands, One reception weight is calculated for each of a plurality of subcarriers for each band, and the reception weight correction unit uses the correction value for a subcarrier existing in the band in which the reception weight is calculated. When the OFDM signal is directionally received using an array antenna, the reception weight is corrected by the correction value. When performing a reception beam formed by the setting of the reception weights is carried out in each divided band in the OFDM signal bandwidth, compensation has the effect of performing for each subcarrier of the OFDM signal.

  The invention according to claim 10 of the present invention is a reception weight calculation unit for calculating a reception weight for directional transmission using an OFDM signal, and a reception correction value for storing a correction value for correcting the reception weight. A memory unit, and a reception weight correction unit that corrects the reception weight with the correction value. The reception correction value memory unit divides the signal bandwidth of the OFDM signal into a plurality of bands, One correction value is stored for each of the bands for a plurality of subcarriers existing in the antenna, and when receiving an OFDM signal directionally using an array antenna, the reception weight is corrected by the correction value. When performing reception beam forming, the correction value has an effect of correcting the amplitude deviation and phase deviation between the reception branches for each divided band within the OFDM signal bandwidth.

  According to an eleventh aspect of the present invention, there is provided a reception weight calculation unit for calculating a reception weight for directional transmission using an OFDM signal, and a reception correction value for storing a correction value for correcting the reception weight. A memory unit, and a reception weight correction unit that corrects the reception weight with the correction value. The reception correction value memory unit divides the signal bandwidth of the OFDM signal into a plurality of bands, The number of correction values smaller than the number of subcarriers present in the band is stored for each of the plurality of subcarriers in the band, and an OFDM signal is transmitted using an array antenna. When performing reception beam shaping by correcting the reception weight with the correction value, the correction value indicates the amplitude deviation and phase deviation between the reception branches and the OFDM signal bandwidth. An effect that is a value corrected for each divided band.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block connection diagram of a radio base station apparatus according to the first embodiment of the present invention. This radio base station apparatus is an apparatus for transmitting a signal of an OFDM modulation scheme, has an array antenna composed of a plurality of antenna elements, and controls the amplitude and phase of a signal radiated from each antenna element, Enable directional transmission. Here, detailed description of the OFDM modulation scheme is omitted. The description of OFDM includes, for example, the document “˜OFDM modulation technology for digital broadcasting / mobile communication” (Makoto Itami, Trikes, 1999).

  In FIG. 1, 100 is a transmission data generation unit, 102-1, 102-2,... 102-N is a weighting operation unit, 103-1, 103-2,. IFFT) arithmetic units, 104-1, 104-2,... 104-N are digital / analog (D / A) converters, 105-1, 105-2,. 106-N are antenna elements, 111 is a transmission weight calculation unit, 112 is a transmission correction value memory unit, and 113 is a transmission weight correction unit. Reference numeral 101 denotes a transmission branch in which a weighting calculation unit 102, an IFFT calculation unit 103, a D / A conversion unit 104, and a transmission radio circuit unit 105 are collected. Here, if the number of antenna elements is N, the number of transmission branches is N.

  In FIG. 1, St1 is a transmission data string generated by the 100 transmission data generation unit, Wt1 is a transmission weight calculated by the 111 transmission weight calculation unit, and Ct is stored in the 112 transmission correction value memory unit. Wt2 is the output transmission weight of the transmission weight correction unit 113, St2-1, St2-2,... St2-N is the output signal of each of the weighting calculation units 102, St3-1, St3-2, ... St3-N is the output signal of each IFFT operation unit 103, St4-1, St4-2, ... St4-N is the output signal of each D / A conversion unit 104, St5-1, St5- 2,..., St5-N are output signals of 105 transmission system radio circuit units.

  The radio base station apparatus configured as described above will be described below.

  The transmission data generation unit 100 generates information to be transmitted and outputs a transmission data string St1. In general, the transmission data string St1 has a radio access channel configuration and is subjected to processing such as encoding and multiplexing. For example, in frequency division multiplexing (Frequency Division Multiple Access, FDMA), multiplexing is performed in the frequency domain, and in time division multiplexing (Time Division Multiple Access, TDMA), multiplexing is performed in the time domain, and code division multiplexing is performed. In the system (Code Division Multiple Access, CDMA), there is a process of performing code multiplexing. Here, in the 100 transmission data generation units and the St1 transmission data string, such a signal format is not particularly limited. For example, as the transmission data sequence of St1, there is a complex data sequence composed of an in-phase component (I channel) and a quadrature component (Q channel).

  A transmission weight calculation unit 111 calculates a transmission weight Wt1 for controlling the amplitude and phase of the transmission signal radiated from each antenna element. In general, the transmission weight is complex data that can represent amplitude and phase. There are several methods for calculating the transmission weight Wt1, but the 111 transmission weight calculation unit is not particularly limited. Here, an example of the transmission weight calculation method is as follows. The direction of the mobile station is estimated from the signal from the mobile station received at the base station. The transmission weight is calculated so as to obtain a beam pattern that directs directivity with respect to the direction of the mobile station thus obtained.

  Here, since the transmission signal is an OFDM signal, a transmission weight can be set for each subcarrier. As shown in FIG. 2, when a transmission weight is set for each subcarrier, an optimum transmission weight can be set for each subcarrier by calculating a separate transmission weight for each subcarrier. In FIG. 2, n indicates a subcarrier number. In calculating the transmission weight in this case, the frequency of each subcarrier and the antenna interval of the array antenna associated therewith are required. When the total number of subcarriers of the OFDM signal is F, F calculation processes are required to calculate all transmission weights.

  In addition, as shown in FIG. 2, it is also possible to divide the signal band of the OFDM signal into a plurality of bands and set subcarriers existing in the band as one group with the same transmission weight. In FIG. 2, m indicates the number of the divided band. In this case, it is desirable to use the center frequency of the band to be calculated as the frequency necessary for calculating the transmission weight. When the signal band of the OFDM signal is divided into M signals, M calculation processes are required to calculate all transmission weights. However, it is possible to reduce the amount of calculation compared to the case where the transmission weight is set for each subcarrier. Further, when the OFDM signal band is divided, it may be divided at regular intervals or at irregular intervals. Furthermore, it is possible to set only one transmission weight for all subcarriers. In this case, the transmission weight is calculated only once. The transmission weight Wt1 calculated in this way is output.

  The transmission correction value memory unit 112 stores a correction value Ct for correcting amplitude deviation and phase deviation generated between the 101 transmission branches. When the signal band of the transmission signal is wide, the amplitude deviation and the phase deviation generated between the 101 transmission branches have frequency characteristics that vary depending on the frequency. In the OFDM signal, it is possible to correct such frequency characteristics of amplitude deviation and phase deviation for each subcarrier. Therefore, the transmission correction value memory unit 112 stores a correction value for each subcarrier for each transmission branch. That is, assuming that the number of transmission branches is N and the total number of subcarriers is F, (N × F) correction values are stored.

  Similarly to the transmission weight calculation unit 111, the signal band is divided into a plurality of parts, and the correction values Ct are stored for the number of the divided bands, and only one correction value is obtained for the entire signal band. It is also possible to store only Ct.

  A method for obtaining the correction value Ct for correcting the amplitude deviation and the phase deviation between the transmission branches 101 will be described later. Here, as the data format of the correction value Ct, for example, there is complex number data that can represent the amplitude and the phase.

  The transmission weight correction unit 113 corrects the transmission weight Wt1 calculated by the transmission weight calculation unit 111 with the correction value Ct stored in the transmission correction value memory unit 112. When the transmission weight Wt1 and the correction value Ct are both complex data, it can be corrected by complex multiplication of the transmission weight Wt1 and the correction value Ct. Here, as an example, when the transmission weight Wt1 is calculated for each subcarrier, and the correction value Ct is also stored for each subcarrier, the corrected transmission weight Wt2 output from the 113 transmission weight correction unit is used. Shown below.

  Here, N is the number of elements of the array antenna, and F is the number of subcarriers of the OFDM signal.

  Next, the operation in the 101 transmission branch will be described. The functions of the weighting calculation unit 102, the IFFT calculation unit 103, the D / A conversion unit 104, and the transmission radio circuit unit 105 that constitute each transmission branch are the same. Therefore, here, the operation of the Nth transmission branch will be described as a representative.

  The weighting calculation unit 102-N weights the transmission data St1 output from the 100 transmission data generation unit with the transmission weight Wt2 output from 113. If each of the transmission data St1 and the transmission weight Wt2 is complex number data, it is possible to perform a weighting operation by complex multiplication. Here, an outline of the operation of the weighting calculation unit 102 when the transmission weight Wt2 is set for each subcarrier of the OFDM signal will be described with reference to FIG. In FIG. 3, reference numeral 102 denotes a weighting calculation unit, 102-A denotes a first serial / parallel (S / P) conversion unit, 102-B denotes a second serial / parallel (S / P) conversion unit, 102- Each C is a multiplier. St1 is transmission data output from the 100 transmission data generation unit, Wt2 is transmission weight output from the transmission weight correction unit 113, and outputs the weighted transmission data of St2. The outline of the weighting calculation unit 102 will be described below.

  In general, transmission data is time-series data, and St1 is also time-series data. When a transmission weight is set for each subcarrier of the OFDM signal, weighting can be performed by converting the transmission data St1 for each subcarrier and multiplying the transmission weight for each subcarrier. In order to achieve this, the first S / P converter 102-A converts the transmission data St1 that is serial in time into parallel transmission data corresponding to each subcarrier. The second S / P converter 102-B also converts the transmission weight Wt2 into parallel data for each subcarrier. The 102-C multiplier multiplies transmission data St1 and transmission weight Wt2 that are parallelized for each subcarrier. The output data St2 of each multiplier can be expressed as follows.

  Here, f indicates a subcarrier number. Since the transmission data St1 and the transmission weight Wt2 are generally complex number data, complex multiplication is performed in the 102-C multiplier. Therefore, the output signal St2 of the weighting calculation unit 102 can output a signal for each subcarrier. However, in the example of FIG. 3, the input transmission data St1 is converted into parallel data for each subcarrier, but this is not specified. This can be realized as long as the transmission data St1 remains time-series data and the transmission weight for each subcarrier can be weighted.

  Next, the IFFT operation unit 103 performs inverse Fourier transform on the output data St2 of the weighting operation unit 102. Here, as a calculation method of the inverse Fourier transform, there is a discrete Fourier transform or the like, but the inverse fast Fourier transform (IFFT) is desirable from the viewpoint of calculation time and calculation processing amount. Here, detailed description regarding IFFT is omitted. As shown in FIG. 3, when the output data St2 of the weighting calculation unit 102 is parallel data for each subcarrier, the IFFT calculation unit 103 performs inverse Fourier calculation with the parallel data. When St2 is time-series data, serial / parallel (S / P) conversion is performed once, and inverse Fourier transform is performed as parallel data. As a result of performing the inverse Fourier transform, time waveform transmission data St3 is output. St3 can be expressed as follows.

Here, F ⁻¹ indicates an inverse Fourier transform. Thereafter, the transmission signal is a time waveform, but is shown by a frequency waveform. The D / A conversion unit 104 converts the output time waveform transmission data St3 from the IFFT operation unit 103 from a digital signal to an analog signal. An output signal St4 of the D / A conversion unit 104 is an analog time waveform transmission signal.

  The transmission system radio circuit unit 105 performs frequency conversion on the analog time waveform transmission signal St4, which is an output signal of the D / A conversion unit 104, from the baseband frequency to the radio frequency, and radiates it from the antenna element for power amplification. Perform transmission signal processing in the radio frequency band. In addition, there are filters. Then, a radio transmission signal St5, which is an output signal of the transmission system radio circuit unit 105, is radiated from the antenna element 106.

  Here, the transmission system radio circuit unit 105 includes a large number of analog circuits. In such an analog circuit, characteristic deviations occur between the transmission branches due to individual differences in the elements themselves, and changes in the characteristics of the elements themselves occur due to the influence of ambient temperature and time. Further, in the line to the antenna element, a difference occurs in the delay time between the transmission branches due to the difference in the line length to each antenna, the characteristic of the line, and the like. Further, when transmitting a wideband signal, frequency characteristics occur in the systematic characteristic deviation of each transmission branch as described above.

  Because of these factors, the amplitude phase relationship set by the transmission weight is lost between the antenna elements, and an ideal beam pattern cannot be obtained. Also, when transmitting a wideband signal, a beam pattern that differs depending on the frequency is formed due to the frequency characteristic of the characteristic deviation.

  Here, it is assumed that the frequency characteristics of the amplitude fluctuation and the phase fluctuation in the transmission system radio circuit unit 105 are as follows.

  When Expressions 3 and 4 are used, a transmission signal St5 that is an output of the transmission system radio circuit unit 105 is as follows.

  For example, when there is no correction value, that is, when Ct = 1, the transmission signal St5-N of the Nth branch is as follows.

  The transmission signal St5-1 of the first branch is as follows.

  From Expressions 6 and 7, the transmission signals St5-1 and St5-N radiated from each antenna element include 105 transmission weights Wt1-1 and Wt1-N of each transmission branch weighted to the transmission signal St1, There is an influence of Z-1 and ZN which are amplitude phase fluctuation characteristics of the transmission system radio circuit section. A pattern different from the beam pattern controlled by the transmission weight Wt1 is formed by Z-1 and Z-N.

  Next, a method for obtaining the correction value Ct will be described. The correction value Ct is for detecting the frequency characteristic of the amplitude phase deviation of the transmission system radio circuit unit 105 and correcting the characteristic, so that the frequency characteristic of the amplitude phase deviation of the transmission system radio circuit unit 105 can be detected. If it is good. For example, there are the following methods. This will be described with reference to FIG. In FIG. 4, 100 to 106 and 111 to 113 are the same as the blocks described in FIG. 1, which is a block diagram of the radio base station apparatus according to the present embodiment, and have the same functions. In FIG. 4, 122 is a correction branch radio circuit unit, 123 is an analog / digital (A / D) conversion unit, 124 is a fast Fourier transform (FFT) calculation unit, and 114 is a frequency response correction value detection unit. Reference numeral 121 denotes a correction branch in which 122 correction branch radio circuit units, 123 A / D conversion units, and 124 FFT calculation units are combined.

  In FIG. 4, Sct1 is a transmission signal directly input to the correction branch, Sct2 is an output signal of the correction branch radio circuit unit, Sct3 is an output signal of the A / D conversion unit, Sct4 is an output signal of the FFT operation unit, Ct Is an output signal of the frequency response correction value detector.

  Here, as shown in FIG. 4, the connection between the 101 transmission branch and the 121 correction branch, and the connection between the 102 weight calculation unit output and the 114 frequency response correction value detection unit, the Nth transmission branch. A correction value detection method will be described. For other transmission branches, the connection of 101 transmission branch and 121 correction branch, and the output of 102 weighting calculation unit and the connection of 114 frequency response correction value detection unit are changed for any branch. There is a similar effect.

  First, the antenna element connected to the 101-N transmission branch is removed. The line connected to the antenna element is connected to the input of 121 correction branches. Thus, the transmission signal St5-N of the Nth transmission branch becomes the input signal Sct1 of the correction branch. As shown in Equation 6, when there is no correction value, that is, when C = 1, Sct1 is as follows.

  This input signal Sct1 is a radio frequency signal. The correction branch radio circuit unit 122 performs frequency conversion of the radio frequency signal to a baseband frequency or an intermediate frequency. In addition, processing such as a filter is included. The 122 correction branch radio circuit units are composed of many analog circuits, like the 105 transmission system radio circuit units. Due to the characteristics of the analog element, a frequency characteristic is generated in the second wireless circuit unit 122. This frequency characteristic is assumed as follows.

  From Expressions 8 and 9, the output signal Sct2 from the correction branch wireless circuit unit 122 is as follows.

  The A / D converter 123 converts the analog signal Sct2 output from the correction branch radio circuit 122 into a digital signal Sct3. Here, the clock used for the 123 A / D converter is the same as that of the 104 D / A converter, so that the 123 A / D converter has the same sampling rate as the 104 D / A converter. In addition, a synchronized digital signal Sct3 can be output.

  The FFT calculation unit 124 performs Fourier transform on the digital signal Sct3 output from the A / D conversion unit 123 and outputs frequency waveform data Sct4. The frequency waveform data Sct4 is input to the frequency response correction value detection unit 114.

  Further, the output signal St2 of the weighting calculation unit 102 is input to the frequency response correction value detection unit 114 as with the frequency waveform data Sct4. At this time, the signal St2 of the transmission branch connected to the correction branch is input. Here, since the correction value is detected for the Nth transmission branch, the signal St2-N is input to the 114 frequency response correction value detector.

  The frequency response correction value detection unit 114 detects the frequency characteristics of the amplitude deviation and phase deviation of the signal Sct2 from the correction branch 121 with reference to the output signal St2 of the weighting calculation unit in the transmission branch 102. Assuming that the frequency characteristic of the amplitude deviation and the phase deviation is h, for example, there are the following detection methods.

  From the frequency characteristic h of the amplitude deviation and the phase deviation thus obtained, the correction value Ct can be obtained as follows.

  In this way, it is possible to detect the correction value Ct-N for correcting the frequency characteristics of the amplitude deviation and the phase deviation of the transmission system radio circuit unit 105-N with respect to the N-th transmission branch of 101-N. Then, the detected correction value Ct-N can be input and stored in the 112 transmission correction value memory unit to be used when correcting the transmission weight. Then, by performing this correction value detection operation for all transmission branches, the correction values for all branches and all subcarriers can be stored in the 112 transmission correction value memory unit.

  The correction value Ct stored in the 112 transmission correction value memory unit includes the frequency characteristic Zc in the 122 correction branch radio circuit units in the 121 correction branch. Since it is common to all branches, the relative relationship between the branches in each subcarrier is maintained, so that the transmission weight is not affected. However, it is possible to remove the frequency characteristic Zc from the correction value Ct by separately measuring only the correction branch 121 and detecting the frequency characteristic Zc of the 122 correction branch radio circuit unit.

  As described above, according to the embodiment of the present invention, when a wideband OFDM signal is directionally transmitted, amplitude and phase deviations and frequency characteristics that occur between transmission branches are corrected for each subcarrier. Therefore, it is possible to form a desired beam pattern within the bandwidth of the OFDM signal, thereby realizing efficient transmission.

  When the radio base station apparatus according to the present embodiment is used for FDMA, 100 transmission data generation units generate signals that are frequency-multiplexed so that a plurality of subcarriers are allocated for each user. In addition, the transmission weight calculation unit 111 generates a transmission weight for each subcarrier assigned to each user corresponding to the data generated by the 100 transmission data generation unit.

  When the radio base station apparatus according to the present embodiment is used for TDMA, 100 transmission data generation units generate time-multiplexed signals so that time is allocated for each user. In addition, the transmission weight calculation unit 111 performs processing for each user divided by time in the transmission weight correction unit 113 and each weighting calculation unit 102.

  When the radio base station apparatus according to the present embodiment is used for CDMA, transmission data is generated for each user, a transmission weight is calculated for each user, weighting is performed for each user, and then code multiplexing is performed. Is done.

(Embodiment 2)
FIG. 5 is a block connection diagram of a radio base station apparatus according to the second embodiment of the present invention. In FIG. 5, reference numeral 200 denotes a transmission data generation unit, 202-1, 202-2,... 202-N denotes a weighting calculation unit, 203-1, 203-2,. IFFT) arithmetic units, 204-1, 204-2,... 204-N are digital / analog (D / A) converters, 205-1, 205-2,. 206-N are antenna elements, 207-1, 207-2,... 207-N are power distribution means, 211 is a transmission weight calculation unit, and 212 is transmission correction. Value memory unit, 213 is a transmission weight correction unit, 214 is a frequency response correction value detection unit, 222 is a correction branch radio circuit unit, 223 is an analog / digital (A / D) conversion unit, and 224 is a fast Fourier transform (FFT) operation Part Reference numeral 201 denotes a transmission branch including a weighting calculation unit 202, an IFFT calculation unit 203, a D / A conversion unit 204, and a transmission radio circuit unit 205, and 221 a correction branch radio circuit unit 222. 223 is a correction branch in which the A / D conversion unit 223 and the FFT calculation unit 224 are combined. Here, if the number of antenna elements is N, the number of transmission branches is N, and the correction branches are also N.

  In FIG. 5, St1 is a transmission data string generated by the 200 transmission data generation unit, Wt1 is a transmission weight calculated by the 211 transmission weight calculation unit, and Ct is stored in the 212 transmission correction value memory unit. Wt2 is the output transmission weight of the transmission weight correction unit 213, St2-1, St2-2,... St2-N is the output signal of each weighting operation unit 202, St3-1, St3-2 ... St3-N is the output signal of each IFFT operation unit 203, St4-1, St4-2, ... St4-N is the output signal of each D / A conversion unit 204, St5-1, St5- 2,..., St5-N is an output signal of each transmission system radio circuit unit 205, Sct1 is a signal distributed by the power distribution means 207 and inputted to the correction branch 221 and Sct2 is 2 2 is an output signal of the correction branch radio circuit unit, Sct3 is an output signal of the A / D conversion unit of 223, Sct4 is an output signal of the FFT operation unit of 224, and Ct is an output correction value of the frequency response correction value detection unit of 214. is there.

  The radio base station apparatus configured as described above will be described below.

  201 composed of 200 transmission data generation units, 202 weighting operation units, 203 IFFT operation units, 204 D / A conversion units, 205 transmission system radio circuit units, and 202 to 205 blocks. The basic operations in the transmission branches, the antenna elements in 206, the transmission weight calculation unit in 211, the transmission correction value memory unit in 212, and the transmission weight correction unit in 213 are the same as the operations in the blocks in the first embodiment. is there.

  The basic operation of the correction branch wireless circuit unit 222, the A / D conversion unit 223, the FFT operation unit 224, and the correction branch 221 configured by the blocks 222 to 224 is described in the first embodiment. The operation is the same as that of each block in FIG. When the number of antenna elements is N, the number of transmission branches is N, and one correction branch is provided for each transmission branch. Therefore, the number of correction branches is N.

  Differences from the first embodiment will be described below. The present embodiment is a radio base station apparatus that performs directional transmission as in the first embodiment. In the first embodiment, in order to detect a correction value for correcting an amplitude deviation or phase deviation between transmission branches and a frequency characteristic thereof, a method of detecting and storing a correction value by removing an antenna element from each transmission branch And configuration. This is effective when there is no change in the amplitude deviation and phase deviation between the transmission branches and the frequency characteristics thereof with respect to the passage of time or the change is negligible. However, if these changes are so large that the stored correction value cannot be corrected, the antenna must be removed and the correction value must be detected and stored each time. Is problematic because it stops communication.

  Therefore, in the present embodiment, it is realized to detect and store the correction value without removing the antenna and without stopping communication. In the present embodiment, 207 power distribution means are installed in the vicinity of 206 antenna elements. Since all operations are the same for each transmission branch, only the Nth branch will be described here as a representative.

  The power distribution means 207-N distributes the power of the transmission signal St5-N output from the transmission branch 201-N and outputs it to the correction branch 221-N. At that time, a small amount of power that does not affect the power supplied to the antenna element 206-N is distributed. The power-distributed transmission signal is input to the correction branch 221-N. The basic operation of the correction branch 221-N is the same as the operation of the correction branch of FIG. Therefore, the correction branch 221-N outputs the frequency waveform data Sct4-N. The frequency waveform data Sct4-N is input to the frequency response correction value detection unit 214. Similarly, the output signal St2-N of the weighting calculation unit 202-N in the transmission branch 201-N is also input to the frequency response correction value detection unit 214. In the frequency response correction value detection unit 214, as in the example shown in the first embodiment, the frequency waveform from the correction branch 221-N is based on the output signal St2-N of the weighting calculation unit 202-N. The frequency characteristic of the amplitude deviation and phase deviation of the data Sct4-N is detected, and the correction value Ct-N of the 205-N transmission radio circuit unit in the Nth transmission branch is detected. At this time, the characteristics of the 222-N correction branch radio circuit unit in the correction branch of 221-N are measured in advance and stored. Then, the correction value Ct-N of the Nth transmission branch detected by the frequency response correction value detection unit 214 is stored in the 212 transmission correction value memory unit. By providing the above configuration for each transmission branch, it is possible to detect the correction value of the transmission radio circuit unit in each transmission branch in parallel in time. The correction value memory unit 212 stores the correction value of the transmission system radio circuit unit of each transmission branch, and performs directivity transmission with a desired beam pattern from each antenna by the same operation as in the first embodiment. It can be carried out.

  As described above, according to the invention of the present embodiment, the same effect as that of the invention described in Embodiment 1 can be corrected so as to always form a desired beam pattern without stopping communication. It is possible to realize efficient transmission.

  The signal used for detecting the correction value is a transmission signal transmitted from the radio base station apparatus, and the correction value can be detected using any part of the transmission signal. A signal such as a transmission pilot signal transmitted at a timing determined in time may be used, or a transmission data signal that is always communicated may be used.

  Although the correction value is detected for each transmission branch, it is possible to improve the accuracy of the correction value by performing detection a plurality of times and taking the temporal average value as the correction value.

  Although the correction value is detected for each subcarrier, it is possible to improve the accuracy of the correction value by taking an average value using the correction values of adjacent subcarriers and using the correction value.

(Embodiment 3)
FIG. 6 is a block connection diagram of a radio base station apparatus according to the third embodiment of the present invention. 6, 300 is a transmission data generation unit, 302-1 and 302-2,... 302-N are weighting operation units, 303-1, 303-2,... 303-N are inverse fast Fourier transforms ( IFFT) arithmetic units, 304-1, 304-2,... 304-N are digital / analog (D / A) converters, 305-1, 305-2,. 306-N are antenna elements, 307-1, 307-2,... 307-N are power distribution means, 311 is a transmission weight calculation unit, and 312 is transmission correction. Value memory unit, 313 is a transmission weight correction unit, 314 is a frequency response correction value detection unit, 315 is a first switch, 316 is a second switch, 322 is a correction branch radio circuit unit, 323 is analog / digital (A / D) Conversion unit 324 is a fast Fourier transform (FFT) calculation unit. Reference numeral 301 denotes a transmission branch including a weighting calculation unit 302, an IFFT calculation unit 303, a D / A conversion unit 304, and a transmission wireless circuit unit 305. Reference numeral 321 denotes a correction branch wireless circuit unit 322. 323 is a correction branch in which the A / D conversion unit 323 and the FFT operation unit 324 are combined. Here, if the number of antenna elements is N, there are N transmission branches.

  In FIG. 6, St1 is a transmission data string generated by the 300 transmission data generation unit, Wt1 is the transmission weight calculated by the 311 transmission weight calculation unit, and Ct is stored in the correction value memory unit 312. Correction value, Wt2 is the output transmission weight of the transmission weight correction unit 313, St2-1, St2-2,... St2-N is the output signal of each of the weighting calculation units 302, St3-1, St3-2,. ... St3-N is an output signal of each IFFT operation unit 303, St4-1, St4-2,... St4-N is an output signal of each D / A conversion unit 304, St5-1, St5-2 ,... St5-N is an output signal of each transmission system radio circuit unit 305, Sct1 is a signal output from the first switch 315 and input to the correction branch 321, and Sct2 is 322. The output signal of the positive branch radio circuit section, SCT3 the output signal of the A / D conversion unit 323, Sct4 the output signal of the FFT calculation unit of 324, Ct is the output correction value of the frequency response correction value detection unit 314.

  The radio base station apparatus configured as described above will be described below.

  A transmission data generation unit 300, each weighting calculation unit 302, each IFFT calculation unit 303, each D / A conversion unit 304, each transmission radio circuit unit 305, and each block 302-305 The basic operations of the transmission branches, the antenna elements of 306, the power distribution means of 307, the transmission weight calculation unit of 311, the transmission correction value memory unit of 312, and the transmission weight correction unit of 313 are the same as those in the first embodiment. This is the same as the operation of each block in the second embodiment. The basic operation of the correction branch wireless circuit unit 322, the A / D conversion unit 323, the FFT calculation unit 324, and the correction branch 321 configured by blocks 322 to 324 is described in the first embodiment. The operation is the same as that of each block in FIG.

  Differences from the first embodiment will be described below. The present embodiment shows a system and configuration for correcting the amplitude deviation and phase deviation between the transmission branches and the frequency characteristics thereof without stopping communication as in the second embodiment.

  In the present embodiment, power is distributed to the transmission signal St5 from each transmission branch 301 by each power distribution unit 307. At that time, a slight amount of power that does not affect the power supplied to the antenna element 306-N is distributed. The transmission signal St5 distributed by the power distribution units 307 is input to the first switch 315. The first switch 315 selects one of the input transmission signals and outputs it. The output signal of the first switch 315 is input to the correction branch 321. In the correction branch 321, the frequency waveform data Sct 4 is output and input to the frequency response correction value detection unit 314 as in the second embodiment. Here, when the transmission signal St5-N in the Nth transmission branch is selected in the first switch 315, the output signal Sct4 of the correction branch 321 is the transmission signal St5-N of the Nth transmission branch. Frequency waveform data.

  The second switch 316 receives the output signal St2 of the weighting calculation unit 202 in each of the 301 transmission branches, selects one, and outputs it to the frequency response correction value detection unit 314. At this time, the second switch 316 operates in conjunction with the first switch 315. That is, the transmission branch number to be selected and the selection timing are the same in the first switch 315 and the second switch 316. Therefore, the signal input to the frequency response correction value detection unit 314 is a signal from the same transmission branch. In the frequency response correction value detection unit 314, the amplitude deviation and phase of the output signal from the 324 FFT operation unit are based on the output signal from the second switch 316 as in the example shown in the first embodiment. The frequency characteristic of the deviation is detected, and the correction value Ct-N of the transmission system radio circuit unit of 305-N in the Nth transmission branch is detected. Then, the correction value Ct-N of the Nth transmission branch detected by the frequency response correction value detection unit 314 is stored in the correction value memory unit 312. By switching the transmission branch by interlocking the first switch 315 and the second switch 316 with the above operation, even if the number of correction branches 321 is one, the first in each transmission branch. It is possible to detect the correction value of the wireless circuit section.

  As described above, according to the invention of the present embodiment, the same effect as that of the invention described in Embodiment 1 can be obtained with a simpler configuration than that of Embodiment 2 without stopping communication. Correction can be performed so as to form a pattern, and efficient transmission can be realized.

  Note that the transmission branch selection method in the first switch 315 and the second switch 316 may be determined in advance or may be selected adaptively.

  Note that the transmission branch selection time for the first switch 315 and the second switch 316 may be the same time for each transmission branch, or the selection time may be changed for each transmission branch.

(Embodiment 4)
FIG. 7 is a block connection diagram of a radio base station apparatus according to the fourth embodiment of the present invention. In FIG. 7, 400 is a transmission data generation unit, 401-1, 402-2,... 402-N is a weighting operation unit, 403-1, 403-2,. IFFT) arithmetic units, 404-1, 404-2, ... 404-N are digital / analog (D / A) converters, 405-1, 405-2, ... 405-N are transmission radio circuits. 406-N are antenna elements, 411 is a transmission weight calculation unit, 412 is a transmission correction value memory unit, 413 is a transmission weight correction unit, and 417 is a transmission correction matrix memory unit. is there. Reference numeral 401 denotes a transmission branch in which a weighting operation unit 402, an IFFT operation unit 403, a D / A conversion unit 404, and a transmission radio circuit unit 405 are collected. Here, if the number of antenna elements is N, there are N transmission branches.

  In FIG. 6, St1 is a transmission data string generated by 400 transmission data generation units, Wt1 is a transmission weight calculated by a transmission weight calculation unit 411, and Ct is stored in a transmission correction value memory unit 412. 405 is a correction value for correcting the characteristics of each transmission system radio circuit unit, Mt is a correction matrix for correcting coupling between antenna elements stored in the transmission correction matrix memory unit 414, and Wt2 is a transmission weight correction unit 413. Output transmission weights, St2-1, St2-2,... St2-N are output signals of 402 weighting operation units, St3-1, St3-2,... St3-N are 403 IFFT operation units. , St4-1, St4-2,... St4-N are output signals of 404 D / A converters, St5-1, St5-2,... St5-N are 405. Which is the output signal of the transmission system wireless circuit section.

  The radio base station apparatus configured as described above will be described below.

  401 composed of 400 transmission data generation units, 402 weighting calculation units, 403 IFFT calculation units, 404 D / A conversion units, 405 transmission system radio circuit units, and 402 to 405 blocks. The basic operations of the transmission branches, the antenna elements of 406, the transmission weight calculation unit of 411, the transmission correction value memory unit of 412 are the same as the operations of the blocks in the first embodiment.

  Differences from the first embodiment will be described below. The difference from the first embodiment is that a transmission correction matrix memory unit 414 is provided, a correction matrix Mt for correcting coupling between antenna elements is stored, and a transmission weight correction unit 413 performs transmission weight W01 with respect to transmission weight W01. In addition to correcting the characteristics of the transmission radio circuit unit in each transmission branch, the coupling between antenna elements is corrected.

  As a method for detecting a correction value for correcting the characteristics of each wireless circuit unit 405 in each transmission branch 401, for example, there is the method described in the first embodiment. As a method for correcting the mutual coupling by the antenna elements 406, for example, the following documents are known methods. Literature "Sensor-Array Calibration Using a Maximum-Likelihood Approach" (Boon Chong Ng, Chong Meng Samson See, IEEE Transactions on Antennas and Propagation, vol.44, No.6, June 1996) and, the document "Calibration of a Smart Antenna for Carrying Out Vector Channel Sounding at 1.9 GHz "(Jean-Rene Laroque, John Litva, Jim Reilly, Wireless Personal Communications: Emerg. g Technologies for Enhanced Communications, p.259-268, there is a method that has been shown by 1999). In these documents, the transmission weight is corrected by calculating a correction matrix for correcting the coupling between antenna elements and multiplying the transmission weight. Here, the correction matrix is stored in the correction matrix memory unit 414 as Mt. As a calculation method of the correction matrix Mt, for example, there is a method described in the above-mentioned document. Here, as described in Embodiment 1, since the transmission signal is an OFDM signal, the transmission weight can be corrected for each subcarrier. In order to realize this, the transmission correction matrix memory unit 414 stores a correction matrix for each subcarrier. As a method for calculating the correction matrix for each subcarrier, for example, the method described in the above-mentioned document can be realized by measuring the correction matrix for each subcarrier and calculating the correction matrix. Further, as described in the first embodiment, the signal band of the OFDM signal is divided into a plurality, and subcarriers existing in the band are collectively calculated and stored, or OFDM It is also possible to calculate and store a correction matrix for all the signal bands.

  The transmission weight correction unit 413 performs correction by multiplying the transmission weight calculated by the transmission weight calculation unit 411 by a correction matrix stored in the transmission correction matrix memory unit 414. Further, the transmission weight correction unit 413 simultaneously performs correction on the radio circuit unit of each transmission branch by using the correction value stored in the correction value memory unit 412.

  As described above, according to the invention of the present embodiment, in addition to the effects of the first embodiment, a desired beam pattern is obtained within the bandwidth of the OFDM signal by correcting the coupling between antenna elements for each OFDM subcarrier. Thus, efficient transmission can be realized.

  In the second and third embodiments, the effect of the present embodiment can be obtained by adding the function and operation of the correction matrix memory unit 414 in the present embodiment.

(Embodiment 5)
FIG. 8 is a block connection diagram of a radio base station apparatus according to the fifth embodiment of the present invention. In FIG. 8, 506-1, 506-2,... 506-N are antenna elements, 552-1, 552-2,... 552-N are reception system radio circuit units, 553-1, 553-2. ,... 553-N is an analog / digital (A / D) conversion unit, 554-1, 554-2,... 554-N is a fast Fourier transform (FFT) operation unit, 555-1, 555-2. ,... 555-N is a weighting calculation unit, 561 is a reception weight calculation unit, 562 is a reception correction value memory unit, 563 is a reception weight correction unit, and 550 is a reception data synthesis unit. Reference numeral 551 denotes a reception branch in which the reception system radio circuit unit 552, the A / D conversion unit 553, the FFT operation unit 554, and the weighting operation unit 555 are collected. Here, if the number of antenna elements is N, there are N reception branches.

  In FIG. 8, Sr1-1, Sr1-2,... Sr1-N are signals received by the respective antenna elements 506, and Sr2-1, Sr2-2,. Sr3-1, Sr3-2,... Sr3-N is an output signal of each A / D converter 553, Sr4-1, Sr4-2,. 554, the output signal of each FFT calculation unit, Sr5-1, Sr5-2,... Sr5-N is the output signal of the weighting calculation unit, Wr1 is the reception weight calculated by the reception weight calculation unit 561, Cr is 562 Wr2 is an output reception weight of the reception weight correction unit 563, and Wr2 is a correction value for correcting the characteristics of each of the reception system wireless circuit units 552 stored in the reception correction value memory unit.

  The radio base station apparatus configured as described above will be described below.

  The radio base station apparatus according to the first embodiment is an apparatus that transmits an OFDM signal, whereas the radio base station apparatus according to the present embodiment is an apparatus that receives an OFDM signal, and the transmission system is replaced with a reception system. However, the basic object and method in the present invention are the same.

  First, operations in the antenna element 506 and the reception branch 551 will be described. Each of the antenna elements 506 and each of the reception system radio circuit units 552 constituting each reception branch of 551, each A / D conversion unit of 553, each FFT calculation unit of 554, each weight calculation unit of 555 The functions are the same. Here, the operation of the Nth reception branch will be described as a representative.

  The antenna element 506-N receives the OFDM signal from the mobile station and outputs a signal Sr1-N.

  The reception system wireless circuit unit 552-N amplifies the power of the signal Sr1-N from 506-N and receives the signal in a radio frequency band such as frequency conversion processing from a radio frequency to a baseband frequency or an intermediate frequency. Signal processing is performed and a signal Sr2-N is output. Other wireless circuit processing includes filter processing for the purpose of noise removal and unnecessary signal removal.

  Here, similarly to the transmission system radio circuit unit 105 in the first embodiment, the difference in the characteristics of the analog elements in the reception system radio circuit unit 552 causes an amplitude deviation and a phase deviation between the reception branches.

  The A / D conversion unit 553-N converts the output signal Sr2-N of the reception wireless circuit unit 552-N from an analog signal to a digital signal. The output signal Sr3-N is a digital signal.

  The FFT operation unit of 554-N performs Fourier transform on the output digital signal Sr3-N of the A / D conversion unit of 553-N. Here, the Fourier transform calculation method includes discrete Fourier transform, but fast Fourier transform (FFT) is preferable in terms of calculation time and calculation processing amount.

  The 555-N weighting operation unit weights the output signal Sr4-N of the 554-N FFT operation unit by the reception weight Wr2 output from the 563 reception weight correction unit. The operation is the same as that of the weighting calculation unit 102 in the first embodiment, and weighting is performed for each subcarrier of the OFDM signal. A signal Sr5-N weighted by the reception weight is output. Here, a method of calculating the reception weight Wr2 will be described later.

  The above is the operation of each receiving branch 551. The output signal Sr5 is input to the received data combining unit 550, and the received data combining unit 550 combines the input signals to obtain received data.

  The reception weight calculation unit 561 receives the output signal Sr4 of each of the FFT operation units 554 in each reception branch 551, and calculates the reception weight Wr1 using the information. Although there are several methods for calculating the reception weight, the reception weight calculation unit 561 is not particularly limited. For example, as a method for calculating the reception weight, there is a method for calculating the reception weight for forming the directivity by estimating the arrival direction of the reception signal and using the estimated direction.

  Here, since the reception signal is an OFDM signal, it can be set for each subcarrier when calculating the reception weight Wr1. Further, the signal band of the OFDM signal can be divided into a plurality of bands, and subcarriers existing in the band can be set as one group with the same reception weight. This is the same as the description when the transmission weight Wt is set in the first embodiment.

  The reception correction value memory unit 562 stores a correction value Cr for correcting an amplitude deviation and a phase deviation generated between the reception branches 551 for each subcarrier. Similarly to the reception weight calculation, the signal band is divided into a plurality of bands, and the correction values Cr are stored for the number of the divided bands, and only one correction value Cr is stored for the entire signal band. It is also possible to memorize it.

  The reception weight correction unit 563 corrects the reception weight Wr1 calculated by the reception weight calculation unit 561 with the correction value Cr stored in the reception correction value memory unit 562.

  The above is the description of the operation in the present embodiment.

  Next, a method for obtaining the correction value Cr will be described. The correction value Cr is for detecting the frequency characteristic of the amplitude phase deviation in the receiving wireless circuit unit 552 and correcting the characteristic, so that the frequency characteristic of the amplitude phase deviation in the receiving wireless circuit unit 552 can be detected. It ’s fine. For example, there are the following methods. This will be described with reference to FIG. Although the transmission system and the reception system are switched, the basic correction value detection operation is the same as the example described in the first embodiment.

  9 adds blocks of a reference signal generation unit 570, an IFFT calculation unit 573, a D / A conversion unit 574, and a correction branch radio circuit unit 575 to the radio base station apparatus shown in FIG. It is a block diagram. The functions and operations of the IFFT operation unit 573, the D / A conversion unit 574, and the correction branch radio circuit unit 575 are the IFFT operation unit 103 and the D / A conversion unit 104 in the transmission branch according to the first embodiment. , 105 is the same as the transmission system radio circuit unit, and these are collectively referred to as a correction branch 571.

  The reference signal generator 570 generates a reference signal Scr1. In the correction branch 571, Scr1 is input and a signal Scr4 subjected to transmission processing is output. The transmission process corresponds to the transmission branch process in the first embodiment. In the radio base station apparatus, the antenna element 506 is removed from the reception branch 551, and the signal Scr4 from the correction branch 571 is directly input.

  In the reception branch 551, reception processing is performed on the input signal Scr4, and Sr4, which is an output signal of the FFT operation unit 553, is input to the frequency response correction value detection unit 564. The frequency response correction value detection unit 564 receives the signal Scr1 from the reference signal generation unit 570.

  The frequency response correction value detection unit 564 detects the amplitude deviation and the phase deviation of the signal Sr4 from the reception branch for each subcarrier using the signal Scr1 from the reference signal generation unit 570 as a reference, and a correction value for each subcarrier. Is calculated.

  By performing the above detection method for all reception branches, correction values Cr for all branches and all subcarriers can be stored in the reception correction value memory unit 562.

  As described above, according to the present invention, amplitude and phase deviations and frequency characteristics that occur between reception branches when a wideband OFDM signal is directionally transmitted are corrected for each subcarrier. As a result, a desired beam pattern can be formed within the bandwidth of the OFDM signal, thereby realizing efficient reception.

  As shown in FIG. 9, a reception correction matrix memory unit for storing a correction matrix for correcting coupling between antenna elements can be added to the present embodiment. The correction matrix for correcting the coupling between the antenna elements has been described in the fourth embodiment. By doing so, in addition to correction of amplitude and phase deviation between reception branches, correction of coupling between antenna elements can be performed, and efficient reception can be realized.

(Embodiment 6)
FIG. 10 is a block connection diagram of a radio base station apparatus according to the sixth embodiment of the present invention. 10, 600 is a transmission data generation unit, 602-1,... 602-N is a weighting operation unit, 603-1,... 603-N are IFFT operation units, 604-1,. N is a D / A conversion unit, 605-1, ... 605-N is a transmission radio circuit unit, 606-1, ... 606-N is an antenna element, 608-1, ... 608-N is Switch means, 611 is a transmission weight calculation unit, 612 is a transmission correction value memory unit, 613 is a transmission weight correction unit, 650 is a reception data synthesis unit, 652-1,... 652-N is a reception system radio circuit unit, 653 -1,... 653-N is an A / D conversion unit, 654-1,... 654-N is an FFT operation unit, 655-1 ... 655-N is a weighting operation unit, and 661 is a reception weight. A calculation unit 662 is a reception correction value memory unit 66. Is a receiving weight correction unit. Reference numeral 601 denotes a transmission branch in which a weighting calculation unit 602, an IFFT calculation unit 603, a D / A conversion unit 604, and a transmission wireless circuit unit 605 are combined. 651 is a reception wireless circuit unit 652. , 653 A / D converter, 654 FFT calculator, and 655 weight calculator. Here, if the number of antenna elements is N, the number of transmission branches and the number of reception branches are N.

  In FIG. 10, St1 is a signal output from the transmission data generation unit, St2 is an output signal of each weighting calculation unit 602, St3 is an output signal of each IFFT calculation unit 603, and St4 is each D / A of 604. An output signal of the conversion unit, St5 is an output signal of each transmission system radio circuit unit 605, Sr1 is a reception signal received by each antenna element, Sr2 is an output signal of each reception system radio circuit unit 652, and Sr3 is 653 , Sr4 is an output signal of each of the 654 FFT operation units, and Sr5 is an output signal of each of the 655 weighting operation units. Wt1 is a transmission weight calculated by the transmission weight calculation unit 611, Ct is a transmission correction value stored in the transmission correction value memory unit 612, and Wt2 is an output transmission weight of the transmission weight correction unit 613. Wr1 is a reception weight calculated by the reception weight calculation unit 661, Cr is a reception correction value stored in the reception correction value memory unit 662, and Wr2 is an output reception weight of the reception weight correction unit 663.

  The radio base station apparatus configured as described above will be described below.

  Reference numeral 601 includes a transmission data generation unit 600, weighting calculation units 602, IFFT calculation units 603, D / A conversion units 604, transmission radio circuit units 605, and blocks 602 to 605. The basic operations of the transmission branches, the antenna elements of 606, the transmission weight calculation unit of 611, the transmission correction value memory unit of 612, and the transmission weight correction unit of 613 are the same as the operations of the blocks in the first embodiment. is there.

  Also, it is composed of 650 received data synthesizing units, 652 receiving radio circuit units, 653 A / D conversion units, 654 FFT computing units, 655 weighting computing units, and 652 to 655 blocks. The basic operations in the respective reception branches 651, the reception weight calculation unit 661, the reception correction value memory unit 662, and the reception weight correction unit 663 are the same as the operations of the respective blocks in the fifth embodiment.

  In the present embodiment, 608 switch means is installed in the vicinity of each antenna element 606, and a transmission signal from the transmission branch to the antenna element and a reception signal from the antenna element to the reception branch are switched to transmit each signal. Thus, the operations of the first embodiment and the fifth embodiment are combined.

  In each of the switch means 608, the signal from the transmission branch 601 is transmitted only to the 606 antenna element and not transmitted to the reception branch 651. Further, the signal from the 606 antenna element is transmitted only to the reception branch 651 and not transmitted to the transmission branch 601.

  The reception weight calculation unit 661 calculates the reception weight Wr1 using the signal Sr4 obtained by processing the received signal. The transmission weight calculation unit 611 can calculate the transmission weight Wt1 using the reception weight Wr1 calculated by the reception weight calculation unit 661. For example, in the time division duplex method (Time Division Duplex, TDD), the reception weight Wr1 is used as it is as the transmission weight Wt1, and in the frequency division duplex method (Frequency Division Duplex, FDD), the reception direction information from the reception weight Wr1. Is used for calculating the transmission weight Wt1.

  As described above, according to the invention of the present embodiment, amplitude and phase deviations and frequency characteristics that occur between transmission branches and between reception branches when performing directional transmission and reception of wideband OFDM signals. Is corrected for each subcarrier, a desired beam pattern can be formed within the bandwidth of the OFDM signal, thereby realizing efficient transmission and reception.

  Similarly to the present embodiment, by combining the radio base station apparatuses according to the second embodiment and the fifth embodiment, a radio base station apparatus having the functions described in the respective embodiments can be realized.

  Similarly to the present embodiment, by combining the radio base station apparatuses according to the third and fifth embodiments, a radio base station apparatus having the functions described in the respective embodiments can be realized.

  Similarly to the present embodiment, by combining the radio base station apparatuses according to the fourth and fifth embodiments, radio base station apparatuses having the functions described in the respective embodiments can be realized.

Block connection diagram of radio base station apparatus according to Embodiment 1 of the present invention OFDM signal reception weight allocation conceptual diagram in Embodiment 1 Operational concept diagram of weighting operation unit in embodiment 1 Block connection diagram showing an example of a correction value detection method in the first embodiment Block connection diagram of radio base station apparatus according to Embodiment 2 Block connection diagram of radio base station apparatus according to Embodiment 3 Block connection diagram of radio base station apparatus according to Embodiment 4 Block connection diagram of radio base station apparatus according to Embodiment 5 Block connection diagram showing an example of a correction value detection method in the fifth embodiment Block connection diagram of radio base station apparatus according to Embodiment 6

Explanation of symbols

100, 200, 300, 400, 600 Transmission data generation unit 101, 201, 301, 401, 601 Transmission branch 102, 202, 302, 402, 602 Weighting operation unit 103, 203, 303, 403, 603 Inverse fast Fourier transform ( IFFT) arithmetic units 104, 204, 304, 404, 604 Digital / analog (A / D) converters 105, 205, 305, 405, 605 Transmission system radio circuit units 106, 206, 306, 406, 505, 606 Antenna elements 207, 307 Power distribution means 608 Switch 111, 211, 311, 411, 611 Transmission weight calculation unit 112, 212, 312, 412, 612 Transmission correction value memory unit 113, 213, 313, 413, 613 Transmission weight correction unit 114, 214, 314 Frequency response correction Value detection unit 315 First switch 316 Second switch 417 Transmission correction matrix memory unit 102-A First serial / parallel (S / P) conversion 102-B Second serial / parallel (S / P) conversion 103 -C multipliers 550 and 650 reception data synthesis units 551 and 651 reception branches 552 and 652 reception radio circuit units 553 and 653 analog / digital (A / D) conversion units 554 and 654 fast Fourier transform (FFT) calculation units 555, 655 Weighting calculation unit 561, 651 Reception weight calculation unit 562, 652 Reception correction value memory unit 563, 653 Reception weight correction unit

Claims (27)

A transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal;
A transmission correction value memory unit for storing a correction value for correcting the transmission weight;
A transmission weight correction unit that corrects the transmission weight with the correction value;
The transmission weight calculation unit divides the signal bandwidth of the OFDM signal into a plurality, and calculates one transmission weight for each of the plurality of subcarriers existing in the divided band for each band.
The radio base station apparatus, wherein the transmission weight correction unit corrects the transmission weight using the correction value for a subcarrier existing within a band in which the transmission weight is calculated. A transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal;
A transmission correction value memory unit for storing a correction value for correcting the transmission weight;
A transmission weight correction unit that corrects the transmission weight with the correction value;
The transmission correction value memory section divides the signal bandwidth of the OFDM signal into a plurality of pieces, and stores one correction value for each of the plurality of subcarriers existing in the divided bands. A radio base station apparatus. A transmission weight calculation unit for calculating a transmission weight for directional transmission using an OFDM signal;
A transmission correction value memory unit for storing a correction value for correcting the transmission weight;
A transmission weight correction unit that corrects the transmission weight with the correction value;
In the transmission correction value memory unit, the signal bandwidth of the OFDM signal is divided into a plurality of subcarriers existing in the divided band, and the number of subcarriers existing in the band is A radio base station apparatus that stores a smaller number of correction values for each band.   The radio base station apparatus according to any one of claims 1 to 3, wherein the transmission correction value memory unit stores a correction value for correcting a deviation occurring between transmission branches.   4. The radio base station according to claim 1, wherein the transmission correction value memory unit stores a correction value for correcting an amplitude deviation and a phase deviation that occur between transmission branches. 5. apparatus.   The radio base station apparatus according to claim 1, wherein the transmission correction value memory unit stores a correction value for each band.   The radio base station apparatus according to claim 1, wherein the transmission correction value memory unit stores a smaller number of correction values than the number of subcarriers existing in the band. A transmission correction matrix memory for storing a correction matrix for correcting coupling between antenna elements;
In the transmission weight correction unit, the transmission weight calculated by the transmission weight calculation unit is corrected by using the correction value stored in the transmission correction value memory unit, and stored in the transmission correction matrix memory unit. The radio base station apparatus according to any one of claims 1 to 7, wherein correction is performed using a correction matrix. A reception weight calculation unit for calculating a reception weight for directivity reception using an OFDM signal;
A reception correction value memory unit for storing a correction value for correcting the reception weight;
A reception weight correction unit that corrects the reception weight with the correction value;
The reception weight calculation unit divides the signal bandwidth of the OFDM signal into a plurality of parts, calculates one reception weight for each of the plurality of subcarriers existing in the divided band, and
The radio base station apparatus, wherein the reception weight correction unit corrects the reception weight using the correction value for a subcarrier existing in a band in which the reception weight is calculated. A reception weight calculation unit for calculating a reception weight for directional transmission using an OFDM signal;
A reception correction value memory unit for storing a correction value for correcting the reception weight;
A reception weight correction unit that corrects the reception weight with the correction value;
In the reception correction value memory unit, the signal bandwidth of the OFDM signal is divided into a plurality of, and one correction value is stored for each of the plurality of subcarriers existing in the divided band. A radio base station apparatus. A reception weight calculation unit for calculating a reception weight for directional transmission using an OFDM signal;
A reception correction value memory unit for storing a correction value for correcting the reception weight;
A reception weight correction unit that corrects the reception weight with the correction value;
In the reception correction value memory unit, the signal bandwidth of the OFDM signal is divided into a plurality of subcarriers existing in the divided band, and the number of subcarriers existing in the band is A radio base station apparatus that stores a smaller number of correction values for each band.   The radio base station apparatus according to any one of claims 9 to 11, wherein the reception correction value memory unit stores a correction value for correcting a deviation occurring between reception branches.   The radio base station according to any one of claims 9 to 11, wherein the reception correction value memory unit stores correction values for correcting amplitude deviations and phase deviations generated between reception branches. apparatus.   The radio base station apparatus according to claim 9, wherein the reception correction value memory unit stores a correction value for each band.   The radio base station apparatus according to claim 9, wherein the reception correction value memory unit stores a smaller number of correction values than the number of subcarriers existing in the band. A reception correction matrix memory for storing a correction matrix for correcting coupling between antenna elements;
In the reception weight correction unit, the reception weight calculated by the reception weight calculation unit is corrected using the correction value stored in the reception correction value memory unit, and is stored in the reception correction matrix memory unit. The radio base station apparatus according to any one of claims 9 to 15, wherein correction is performed using a correction matrix. In a radio base station apparatus that has an array antenna composed of a plurality of antenna elements and communicates with a mobile station using an OFDM signal,
A transmission weight calculation unit for calculating a transmission weight for directional transmission;
A transmission correction value memory unit for storing a correction value for correcting the transmission weight;
A transmission weight correction unit for correcting the transmission weight with the correction value;
A transmission data generation unit that generates an information data string to be transmitted;
A plurality of weighting calculators for weighting transmission data output from the transmission data generation unit with transmission weights output from the transmission weight correction unit;
A plurality of inverse fast Fourier transform computation units for performing inverse Fourier transform on the output signal of the weighting computation unit;
A plurality of D / A converters for converting an output signal of the inverse fast Fourier transform operation unit into an analog signal;
A plurality of transmission system radio circuit units that perform frequency conversion to radio frequency on the output analog signal of the D / A conversion unit;
A plurality of antenna elements that radiate the output signal of the transmission branch that combines the plurality of transmission system radio circuit units;
A plurality of power distribution means connected to the plurality of antenna elements;
A first switch that selects and outputs one of the signals distributed by the plurality of power distribution means;
A correction branch radio circuit unit that inputs a signal output from the first switch and performs frequency conversion at least at a radio frequency;
An A / D converter that converts the output signal of the correction branch radio circuit unit into a digital signal;
A fast Fourier transform operation unit that performs Fourier transform on the output digital signal of the A / D conversion unit;
A second switch for selecting and outputting one of the signals before inverse Fourier transform in the plurality of transmission branches;
A frequency response correction detection unit for detecting a correction value by inputting an output signal of the fast Fourier transform calculation unit and a signal from the second switch;
The radio base station apparatus, wherein the transmission correction value memory unit stores the correction value detected by the frequency response correction value detection unit.   The radio base station apparatus according to claim 17, wherein the first switch and the second switch operate in conjunction so as to select the same transmission branch.   The frequency response correction value detection unit detects the amplitude and phase of the output signal of the fast Fourier transform operation unit for each subcarrier of the OFDM signal with reference to the output signal of the second switch, and the amplitude and phase The radio base station apparatus according to claim 17 or 18, wherein a correction value for correcting an amplitude deviation and a phase deviation between the transmission branches is calculated using a detection result.   The radio base station according to claim 17, wherein the frequency response correction value detection unit detects a correction value using output data from the transmission data generation unit and stores the correction value in the transmission correction value memory unit. Station equipment. In a radio base station apparatus that has an array antenna composed of a plurality of antenna elements and communicates with a mobile station using an OFDM signal,
A transmission weight calculation unit for calculating a transmission weight for directional transmission;
A transmission correction value memory unit for storing a correction value for correcting the transmission weight;
A transmission weight correction unit for correcting the transmission weight with the correction value;
A transmission data generation unit that generates an information data string to be transmitted;
A plurality of weighting calculators for weighting transmission data output from the transmission data generation unit with transmission weights output from the transmission weight correction unit;
A plurality of inverse fast Fourier transform computation units for performing inverse Fourier transform on the output signal of the weighting computation unit;
A plurality of D / A converters for converting an output signal of the inverse fast Fourier transform operation unit into an analog signal;
A plurality of transmission system radio circuit units that perform frequency conversion to radio frequency on the output analog signal of the D / A conversion unit;
A plurality of antenna elements that radiate the output signal of the transmission branch that combines the plurality of transmission system radio circuit units;
A transmission correction matrix memory for storing a correction matrix for correcting coupling between antenna elements,
In the transmission weight correction unit, in addition to correcting the transmission weight calculated by the transmission weight calculation unit with the correction stored in the transmission correction value memory unit, the transmission weight correction unit stores the transmission weight in the transmission correction matrix memory unit. Correct with the correction matrix,
In the transmission correction matrix memory unit, the signal bandwidth of the OFDM signal is divided into a plurality, and a correction matrix for correcting the coupling between antenna elements is calculated in advance for a plurality of subcarriers existing in the divided band. A radio base station apparatus characterized by being stored in advance.   The wireless transmission according to claim 21, wherein the transmission correction matrix memory unit calculates and stores in advance a correction matrix for correcting coupling between antenna elements for each subcarrier of the OFDM signal. Base station device. In a radio base station apparatus that communicates with a mobile station using an OFDM signal,
An array antenna composed of a plurality of antenna elements for receiving signals from a mobile station;
A plurality of reception system radio circuit units that amplify power with respect to signals received by the plurality of antenna elements and perform frequency conversion at least in a radio frequency;
A plurality of A / D converters for converting the output signals of the plurality of reception system radio circuit units into digital signals;
A plurality of fast Fourier transform operation units for performing Fourier transform on the output digital signals of the plurality of A / D conversion units;
A reception weight calculation unit that calculates a reception weight using a plurality of signals output from the plurality of fast Fourier transform calculation units;
A reception correction value memory unit for storing a correction value for correcting the reception weight;
A reception weight correction unit for correcting the reception weight with the correction value;
A plurality of weighting operation units for weighting the output signals from the plurality of fast Fourier transform operation units with the reception weight output from the reception weight correction unit;
A reception data combining unit that combines the output signals of the plurality of weighting calculation units,
The reception weight calculation unit divides the signal bandwidth of the OFDM signal into a plurality of pieces, calculates one reception weight for a plurality of subcarriers existing in the divided band,
The reception weight correction unit corrects each subcarrier using the correction value stored in the reception correction value memory unit with respect to the reception weight calculated by the reception weight calculation unit. A wireless base station device.   The reception weight calculation unit calculates a reception weight for each subcarrier of the OFDM signal, and the reception weight correction unit compares the reception weight calculated by the reception weight calculation unit with the reception correction value memory unit. The radio base station apparatus according to claim 23, wherein correction is performed for each subcarrier using the stored correction value.   25. The reception correction value memory unit stores a correction value for correcting an amplitude deviation and a phase deviation generated between reception branches for each subcarrier of an OFDM signal. The radio base station apparatus described. In a radio base station apparatus that communicates with a mobile station using an OFDM signal,
An array antenna composed of a plurality of antenna elements for receiving signals from a mobile station;
A plurality of reception system radio circuit units that amplify power with respect to signals received by the plurality of antenna elements and perform frequency conversion at least in a radio frequency;
A plurality of A / D converters for converting the output signals of the plurality of reception system radio circuit units into digital signals;
A plurality of fast Fourier transform operation units for performing Fourier transform on the output digital signals of the plurality of A / D conversion units;
A reception weight calculation unit that calculates a reception weight using a plurality of signals output from the plurality of fast Fourier transform calculation units;
A reception correction value memory unit for storing a correction value for correcting the reception weight;
A reception weight correction unit for correcting the reception weight with the correction value;
A plurality of weighting operation units for weighting the output signals from the plurality of fast Fourier transform operation units with the reception weight output from the reception weight correction unit;
A reception data combining unit that combines the output signals of the plurality of weighting calculation units,
In the reception correction value memory unit, the signal bandwidth of the OFDM signal is divided into a plurality of parts, and the amplitude deviation and the phase deviation generated between the reception branches are corrected for a plurality of subcarriers existing in the divided band. A radio base station apparatus storing a correction value to be stored.   Each of the weighting calculation units weights the output signal of the fast Fourier transform calculation unit for each subcarrier by the reception weight of each subcarrier corrected by the reception weight correction unit. Item 27. The radio base station apparatus according to any one of Items 23 to 26.

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