JP4408262B2 - Adaptive antenna array transmission apparatus and adaptive antenna array transmission method - Google Patents

Description

  The present invention relates to an adaptive antenna array transmission apparatus and an adaptive antenna array transmission method used in a radio transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations.

  As a very useful technique for increasing subscriber capacity, cell radius (cell coverage area), and throughput in a cell in a wireless transmission system, there is adaptive antenna array transmission / reception. This is because multiple antennas are arranged in an array, and the antenna gain is increased by directing the main beam toward the direction of arrival of the desired wave signal by adaptively controlling the weighting factor (weight) of each antenna by signal processing. The antenna gain is reduced by directing nulls (zero points) of the directivity toward the arrival direction of the interference wave signal, and directivity can be controlled.

  Adaptive antenna array transmission / reception using the principle of directivity beam transmission / reception is also realized in W-CDMA (Wideband Code Division Multiple Access), which is one of the radio access systems of the third generation mobile communication system. Research and development has been actively conducted. For example, Non-Patent Document 1 shows a reception technique using an adaptive antenna array, and Non-Patent Document 2 shows a transmission technique using an adaptive antenna array.

  In the study of adaptive antenna array transmission / reception shown in these documents, an array antenna is prepared on the base station side in signal transmission between the base station and the mobile station of the mobile communication system, and the mobile station adaptively receives the base station. A receiving antenna weighting factor is generated for each, and efficient directivity reception in the uplink is realized. In addition, calibration is performed on the received antenna weighting coefficient of each antenna obtained to generate a transmitting antenna weighting coefficient, and this is multiplied by the transmission signal to each mobile station, thereby directing in the desired mobile station direction. To reduce interference in the direction of other mobile stations.

  Here, in the wireless transmission systems such as cellular to date, circuit-switched communication represented by voice is the mainstream, and in this case, communication in the uplink and downlink (number of communication channels, data transmission rate, etc.) is symmetric. In addition, the communication channel is continuously transmitted and received. For this reason, in the conventional adaptive antenna array transmission / reception assuming such circuit-switched communication, the uplink reception antenna weighting coefficient is set to an adaptive value such as LMS (Least Mean Square) or RLS (Recursive Least Square) algorithm. The algorithm is used to generate the optimal antenna weighting factor sequentially over a relatively long time. In addition, the transmission antenna weighting coefficient in the downlink is generated by performing calibration based on the weighting coefficient generated in the uplink. This is because, in circuit switching, the direction of a user transmitting a communication channel that causes interference in the uplink is the direction of the user that also causes interference in the downlink.

  However, in the future wireless transmission systems, it is considered that the switching from the circuit switching type to the more efficient packet type is considered in consideration of the compatibility with the Internet network. At this time, the communication channel is transmitted and received in bursts (only when transmitting data packets). Further, as can be seen from an example of data download or the like, the number of uplink and downlink communication channels is different, and the transmission rate is different between uplink and downlink. That is, the symmetry of uplink / downlink communication is greatly lost.

  In such a case, reception antenna weight coefficient generation using an adaptive algorithm such as LMS or RLS takes time to converge, and is inappropriate for short packet transmission. Also, when the user (channel) and data rate communicating in the uplink and the downlink are different, the downlink transmission antenna weight coefficient generated from the reception antenna weight coefficient generated in the uplink In some cases, interference suppression cannot be sufficiently performed. For example, when there are accesses from a large number of users in the uplink and the reception antenna weighting factor and thus the transmission antenna weighting factor are generated based on the access, when only a small number of users are actually transmitted, By forming a null in the direction of the user, the main beam for the original transmission target user becomes dull, and sufficient gain cannot be secured and sufficient interference suppression cannot be performed.

In order to solve these problems, a method for estimating the signal arrival direction for each uplink mobile station in base station reception and generating reception and transmission weighting factors based on the obtained arrival direction estimation results has been proposed. (See, for example, Non-Patent Documents 3 and 4.) Also, downlink propagation path estimation from each transmitting antenna is performed for each mobile station, and the obtained propagation path estimation result is reported via the uplink channel, thereby calculating the optimal transmission weighting coefficient for the downlink. Have been proposed (see, for example, Non-Patent Documents 5 and 6).
S. Tanaka, M. Sawahashi, and F. Adachi, “Pilot symbol-assisted decision-directed coherent adaptive array diversity for DS-CDMA mobile radio reverse link”, IEICE Trans. Fundamentals, Vol. E80-A, pp.2445- 2454, Dec. 1997. A. Harada, S. Tanaka, M. Sawahashi, and F. Adachi, “Performance of Adaptive Antenna Array Diversity Transmitter for W-CDMA Forward Link”, Proc. PIMRC99, pp.1134-1138, Osaka, Japan, Sep. 1999 . T. Kataoka, H. Taoka, K. Higuchi, and M. Sawahashi, “Adaptive Antenna Array-Beam Forming with Simultaneous Received Path Timing and DOA Estimations Based on Two-Dimensional Power Profile in Broadband CDMA Reverse Link”, Proc. ISSSE2004, Linz, Austria, Aug. 2004. T. Taoka, T. Kataoka, K. Higuchi, and M. Sawahashi, “Optimum Beam Generation Method of Adaptive Antenna Array-Beam Forming Transmitter for OFCDM Broadband Packet Wireless Access in Forward Link”, Proc. WPMC2004, Abano Terme, Italy, Sep. 2004. D. Gerlach and A. Paulraj, “Adaptive Transmitting Antenna Arrays with Feedback”, IEEE Signal Processing Letters, vol.1, pp.150-152, Oct. 1994. Hara, Kamio, “Beam-forming method for base station in W-CDMA downlink considering multimedia communication environment”, IEICE Technical Report RCS2001-172, pp.25-32, Nov.2001.

  As described above, various prior art documents exist for adaptive antenna array transmission / reception. However, when packet-type asymmetric communication is assumed, there are the following problems.

  In other words, in the techniques shown in Non-Patent Documents 3 and 4, only the control of the main beam is examined, and the null control is not studied. Therefore, there has been a problem that interference suppression is not sufficient.

  In addition, the techniques disclosed in Non-Patent Documents 5 and 6 have a problem that the amount of information to be fed back via the uplink is enormous, so that the uplink transmission rate is significantly reduced.

  The present invention has been proposed in view of the above-described conventional problems, and the object of the present invention is to perform appropriate main beam and null directivity control and to reduce the amount of information to be fed back. An object of the present invention is to provide an adaptive antenna array transmission apparatus and an adaptive antenna array transmission method suitable for packet communication in which uplink and downlink communication channels and data transmission rates are asymmetric.

  In order to solve the above-described problems, in the present invention, as described in claim 1, wireless transmission in which a plurality of antennas are arranged in an array and signal transmission is simultaneously performed with a plurality of mobile stations. A transmission device in the system, which obtains a signal arrival direction estimation unit that estimates a signal arrival direction based on a reception signal from the mobile station, and a downlink downlink received SINR measurement value measured by the mobile station from the mobile station Mobile station to be transmitted based on the downlink reception SINR measurement value demodulating section, the signal arrival direction estimation value estimated by the signal arrival direction estimation section and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation section Increase the transmit antenna gain according to the downlink received SINR measurement value for the signal arrival direction of the other mobile station, and respond to the downlink reception SINR measurement value for the signal arrival direction of other mobile stations The antenna weighting coefficient for reducing the transmit antenna gain, are summarized as adaptive antenna array transmitting device and an antenna weighting coefficient generator for generating for each mobile station to be transmitted.

  In addition, as described in claim 2, the signal arrival direction estimation unit estimates a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment, and the antenna weight coefficient generation unit includes: An antenna that simultaneously increases the transmission antenna gain with respect to the signal arrival directions of the plurality of paths of the mobile station to be transmitted and simultaneously decreases the transmission antenna gain with respect to the signal arrival directions of the plurality of paths of other mobile stations. A weighting factor can be generated.

  In addition, as described in claim 3, the signal arrival direction estimation unit estimates a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment, and receives the received signals of the plurality of paths. Each of which has a function of measuring power, and the antenna weighting factor generation unit sets a transmission antenna gain with respect to a signal arrival direction of a path having a maximum received signal power among the plurality of paths of the mobile station to be transmitted. It is possible to generate an antenna weighting factor that increases and decreases the transmission antenna gain with respect to the signal arrival direction of the path having the maximum received signal power among the plurality of paths of the other mobile stations.

  In addition, as described in claim 4, the signal arrival direction estimation unit has a function of estimating a signal arrival direction for a plurality of paths having different propagation delay times due to a multipath fading environment, and the signal arrival direction estimation An average arrival direction calculation unit that calculates an average arrival direction of the plurality of paths from a signal arrival direction estimation value estimated by the unit, and the antenna weight coefficient generation unit includes the plurality of paths of the mobile station to be transmitted. To generate an antenna weighting factor that increases the transmission antenna gain with respect to the average signal arrival direction, and decreases the transmission antenna gain with respect to the average signal arrival direction of the plurality of paths of the other mobile stations. can do.

  In addition, as described in claim 5, the signal arrival direction estimation unit estimates a signal arrival direction for a plurality of paths having different propagation delay times due to a multipath fading environment, and receives received signal power of the plurality of paths. And the antenna weighting factor generation unit can generate antenna weighting factors according to the received signal power of the plurality of paths.

  Further, as described in claim 6, the downlink reception SINR measurement value demodulating unit demodulates the downlink reception SINR measurement value after combining the signals of the plurality of paths for each mobile station. Can do.

  In addition, as described in claim 7, an inter-user signal arrival direction difference calculation unit that calculates an angle difference between signal arrival directions from the plurality of mobile stations is provided, and the antenna weight coefficient generation unit includes the calculated angle When the difference is equal to or smaller than a predetermined threshold, the antenna weighting factor can be generated by excluding the signal arrival direction estimation value of the interfering mobile station in the proximity of the signal arrival direction.

Further, as described in claims 8 to 14, the adaptive antenna array transmission method can be configured.

  In the adaptive antenna array transmission apparatus and adaptive antenna array transmission method of the present invention, the antenna weighting factor is calculated based on the signal arrival direction estimation value of each mobile station and the downlink received SINR measurement value obtained by feedback from the mobile station side. Since it is generated, appropriate directivity control of the main beam and null can be performed, and the amount of information to be fed back can be reduced. As a result, throughput in the uplink and downlink can be greatly increased.

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

<First Embodiment>
FIG. 1 is a configuration diagram of an array antenna transmission / reception apparatus according to a first embodiment of the present invention. This array antenna transmission / reception apparatus is provided as a base station apparatus. In addition, in an adaptive antenna array transmission in an actual base station, calibration is required to compensate for individual differences in the amplitude and phase of the RF circuit as many as the number of transmitting and receiving antennas. Yes. As for the calibration method, for example, the literature “Fukino, Takeuchi,“ Automatic calibration method using LMS algorithm of radio section of array antenna in DS-CDMA ”, IEICE Technical Report RCS2000-31, pp.9-16, "June 2000.", "Takasaki, Shiobara, Kosaka," Background radio circuit calibration method for array antenna and its performance ", Shingaku Sodai, B-5-69, Sep. 2001" etc. Therefore, the present invention can be applied to the array antenna transmission / reception apparatus of the present invention.

  In FIG. 1, an array antenna transmission / reception apparatus includes M antennas 101-1 to 101-M for transmission / reception, duplexers 102-1 to 102-M connected to the antennas 101-1 to 101-M, and duplexers, respectively. RF receiving units 103-1 to 103-M, A / D conversion units 104-1 to 104-M, and distributing units 105-1 to 105- connected in sequence to the reception output sides of 102-1 to 102-M, respectively. M.

  Distribution sections 105-1 to 105-M distribute the digitized reception signals to the number of users (mobile stations) K, and the output terminals of distribution sections 105-1 to 105-M receive the received signals. Based on the beamformer method, the capon method, the MUSIC (MUltiple SIgnal Classification) method, etc., the signal arrival direction estimation units 106-1 to 106-K that estimate the signal arrival direction for each user, and the estimated signal arrival direction estimation Antenna combining sections 107-1 to 107-K that combine received signals for each user using the value as a weight are connected. Also, at the output terminals of the antenna combining sections 107-1 to 107-K, demodulating sections 108-1 to 108-K that demodulate the received signals and output the received signal sequences of the respective users are measured on the mobile station side. Downlink received SINR measurement value demodulation sections 109-1 to 109 -K for demodulating the downlink downlink received SINR (Signal-to-Interference plus Noise power Ratio) measurement values are connected. Also, the signal arrival direction estimation value for each user estimated by the signal arrival direction estimation units 106-1 to 106-K and the downlink for each user demodulated by the downlink reception SINR measurement value demodulation units 109-1 to 109-K. An arrival direction / downlink reception SINR measurement value storage unit 110 that holds downlink reception SINR measurement values of the link is provided.

  On the other hand, based on the signal arrival direction estimation value and the downlink reception SINR measurement value stored in the arrival direction / downlink reception SINR measurement value storage unit 110, the downlink reception SINR measurement value is determined according to the signal arrival direction of the user to be transmitted. Antenna weight coefficient generators 111-1 to 111-1 for generating for each user an antenna weight coefficient that increases the transmission antenna gain and decreases the transmission antenna gain according to the downlink reception SINR measurement value with respect to the signal arrival direction of other users. 111-K, frame generators 112-1 to 112-K that perform channel coding, data modulation, and mapping of transmission signal sequences for each user, and output signals of frame generators 112-1 to 112-K as the number of antennas Distributing units 113-1 to 113 -K that distribute to M, and signals distributed by distributing units 113-1 to 113 -K and antenna weights And a multiplying unit 114-1 through 114-K for multiplying the antenna weight coefficient generator 111-1 to 111-K.

  Also, multiplexing units 115-1 to 115 -M that multiplex the outputs of the multiplication units 114-1 to 114 -K for each of the antennas 101-1 to 101 -M, and a D / A conversion unit that is sequentially connected to the subsequent stage. 116-1 to 116-M, and RF transmitters 117-1 to 117-M. The output ends of the RF transmitters 117-1 to 117-M are connected to the transmission input sides of the duplexers 102-1 to 102-M.

FIG. 2 is a diagram illustrating calculation formulas of the antenna weight coefficient generation units 111-1 to 111 -K in the first embodiment. In FIG. 2, Formula 201 shows a formula for calculating the antenna weighting factor w (k) for the user (mobile station) k. The antenna weighting factor w (k) is the antenna correlation matrix R _xx (k) and the steering vector ( It is obtained by calculation with a vector a (k) pointing in the direction of the main beam. Equation 202 shows the component of the steering vector a (k), which is expressed by the number M of array antennas, the antenna interval d, the wavelength λ _d, and the signal arrival direction estimation value θ (k) from the mobile station k. . The term 203 of the antenna correlation matrix R _xx (k) corresponds to the direction in which the main beam is directed, and the term 204 corresponds to the direction of the interference user. The term 205 is a noise component.

That is, in calculating the antenna weighting factor w (k) using Equation 201, the term 203 of the antenna correlation matrix R _xx (k) is calculated as a large value because the direction is aligned with the steering vector a (k). SINR measurement value (SINR) is multiplied by _k . Also, the term 204 of the antenna correlation matrix R _xx (k) is calculated as a small value because the direction is not aligned with the steering vector a (k), and is further multiplied by the downlink received SINR measurement value (SINR) _{k ′.} . Therefore, the transmission antenna gain is increased according to the downlink reception SINR measurement value with respect to the signal arrival direction of the mobile station to be transmitted, and the transmission is performed according to the downlink reception SINR measurement value with respect to the signal arrival directions of other mobile stations. The antenna weighting factor decreases the antenna gain.

  FIG. 3 is a diagram illustrating an example of the transmission beam pattern in the first embodiment, in which the horizontal axis indicates the azimuth angle and the vertical axis indicates the gain. A solid line indicates a transmission beam pattern for the user # 1, and a main beam is formed at an angle 301 where the user # 1 exists, and a null is formed at an angle 302 where the user # 2 exists. Similarly, a broken line indicates a transmission beam pattern for the user # 2, and a main beam is formed at an angle 302 where the user # 2 exists, and a null is formed at an angle 301 where the user # 1 exists.

  As described above, since the antenna weighting factor is generated based on the signal arrival direction of each mobile station and the downlink reception SINR measurement value obtained by feedback from the mobile station side, appropriate directivity control of the main beam and null can be performed. In addition, since only the downlink reception SINR measurement value is fed back from the mobile station side, the amount of information can be reduced.

<Second Embodiment>
FIG. 4 is a block diagram of an array antenna transmission / reception apparatus according to the second embodiment of the present invention. In consideration of a plurality of paths having different propagation delay times in a multipath fading environment, a plurality of paths of a mobile station to be transmitted The transmission antenna gain is simultaneously increased with respect to the signal arrival direction, and the transmission antenna gain is simultaneously decreased with respect to the signal arrival directions of a plurality of paths of other mobile stations. Diversity effect on the desired wave can be expected by considering a plurality of paths.

  In FIG. 4, the signal arrival direction estimation units 106-1 to 106-K are expanded in function to estimate the signal arrival directions for a plurality of paths having different propagation delay times due to the multipath fading environment, and the antenna combining unit 107- The functions of 1 to 107-K have been extended so that antenna combining is performed in consideration of a plurality of paths. In addition, multipath combining units 118-1 to 118 -K that combine multipath signals for each user by RAKE reception or the like are provided after the antenna combining units 107-1 to 107-K. Further, the arrival direction / downlink reception SINR measurement value storage unit 110 has an extended function to store the signal arrival direction estimation value for each path obtained from the signal arrival direction estimation units 106-1 to 106-K, and the antenna weighting factor. The generators 111-1 to 111 -K simultaneously increase the transmission antenna gain with respect to the signal arrival directions of a plurality of paths of a mobile station to be transmitted, and to the signal arrival directions of a plurality of paths of other mobile stations. At the same time, the function has been changed to generate an antenna weighting factor that reduces the transmit antenna gain. Other configurations are the same as those of the first embodiment shown in FIG.

  FIG. 5 is a diagram showing calculation formulas of the antenna weight coefficient generation units 111-1 to 111 -K in the second embodiment, and is an expression considering a plurality of paths of the desired wave and the interference wave.

  FIG. 6 is a diagram showing an example of the transmission beam pattern in the second embodiment. In the transmission beam pattern for the user # 1 indicated by a solid line, the angles 311 and 312 where the path of the user # 1 exists are crossed. A main beam is formed, and nulls are formed at angles 321 and 322 where the path of the user # 2 exists. Similarly, in the transmission beam pattern for the user # 2 indicated by a broken line, the main beam is formed so as to cross the angles 321 and 322 where the path of the user # 2 exists, and the angle 311 where the path of the user # 1 exists, A null is formed at 312.

<Third Embodiment>
FIG. 7 is a configuration diagram of an array antenna transmission / reception apparatus according to the third embodiment of the present invention. In consideration of a plurality of paths having different propagation delay times in a multipath fading environment, a plurality of paths of a mobile station to be transmitted The transmission antenna gain is increased with respect to the signal arrival direction of the path with the maximum received signal power, and transmission is performed with respect to the signal arrival direction of the path with the maximum received signal power among the multiple paths of other mobile stations. The antenna gain is reduced. Although the path diversity effect is reduced as compared with the second embodiment, the main beam and the null can be made sharper by limiting the target paths.

  In FIG. 7, instead of the signal arrival direction estimation units 106-1 to 106-K (FIG. 4), the signal arrival direction is estimated for each of a plurality of paths having different propagation delay times due to the multipath fading environment, and the plurality of paths Signal receiving direction / received signal power measuring units 119-1 to 119-K having a function of measuring the received signal powers of the received signal powers are provided. In addition, the function of the arrival direction / downlink received SINR measurement value storage unit 110 is changed so as to hold the signal arrival direction estimation value that maximizes the received signal power among the plurality of paths of each user, and the antenna weight coefficient generation unit 111. −1 to 111-K increase the transmission antenna gain with respect to the signal arrival direction of the path with the maximum received signal power among the plurality of paths of the mobile stations to be transmitted, and the plurality of paths of other mobile stations. Among these, the function is changed so as to generate an antenna weighting factor that decreases the transmission antenna gain with respect to the signal arrival direction of the path with the maximum received signal power. Other configurations are the same as those of the second embodiment shown in FIG.

  FIG. 8 is a diagram illustrating calculation formulas of the antenna weight coefficient generation units 111-1 to 111 -K in the third embodiment, and the calculation is performed for the path with the maximum received signal power for each of the desired wave and the interference wave. It is a formula.

  FIG. 9 is a diagram illustrating an example of a transmission beam pattern in the third embodiment, and in the transmission beam pattern for the user # 1 indicated by a solid line, the received signal power is the maximum of the two paths of the user # 1. A main beam is formed at an angle 311 where a path exists, and a null is formed at an angle 321 where a path with the maximum received signal power exists among the two paths of user # 2. Similarly, in the transmission beam pattern for user # 2 indicated by a broken line, a main beam is formed at an angle 321 where a path with the maximum received signal power is present among the two paths of user # 2, and user # 1's A null is formed at an angle 311 where there is a path with the maximum received signal power among the two paths. In this case, the angles 312 and 322 where the path where the received signal power does not become maximum are not considered, but the main beam and the null are sharper than those in FIG.

<Fourth Embodiment>
FIG. 10 is a configuration diagram of an array antenna transmission / reception apparatus according to the fourth embodiment of the present invention. In consideration of a plurality of paths having different propagation delay times in a multipath fading environment, a plurality of paths of a mobile station to be transmitted are illustrated. The transmission antenna gain is increased with respect to the average signal arrival direction, and the transmission antenna gain is decreased with respect to the average signal arrival direction of a plurality of paths of other mobile stations. Compared with the third embodiment, the diversity effect can be left to some extent, and the sharpness of the main beam and null can be maintained by limiting the target paths.

  In FIG. 10, the average arrival direction calculation unit 120-1 that calculates the average signal arrival direction of a plurality of paths from the signal arrival direction estimation values estimated by the signal arrival direction / reception signal power measurement units 119-1 to 119-K. ~ 120-K are newly provided. The average signal arrival direction is calculated by weighted averaging the signal arrival direction estimation value of each path with the received signal power for each path (see Non-Patent Document 4 described above). Also, the function of the arrival direction / downlink reception SINR measurement value storage unit 110 is changed so as to hold an average signal arrival direction estimation value of a plurality of paths for each user, and the antenna weight coefficient generation units 111-1 to 111-. K increases the transmission antenna gain with respect to the average signal arrival direction of a plurality of paths of a mobile station to be transmitted, and the transmission antenna with respect to the average signal arrival direction of a plurality of paths of other mobile stations. The function has been changed to generate an antenna weighting factor that reduces the gain. Other configurations are the same as those of the third embodiment shown in FIG.

  FIG. 11 is a diagram illustrating calculation formulas of the antenna weight coefficient generation units 111-1 to 111 -K in the fourth embodiment, and the average signal arrival directions of a plurality of paths for each of the desired wave and the interference wave. It is a formula to calculate.

  FIG. 12 is a diagram illustrating an example of the transmission beam pattern in the fourth embodiment. In the transmission beam pattern for the user # 1 indicated by the solid line, the center positions (311 and 312) where the path of the user # 1 exists ( The main beam is formed at the average angle position), and nulls are formed at the center positions of the angles 321 and 322 where the path of the user # 2 exists. Similarly, in the transmission beam pattern for the user # 2 indicated by the broken line, the main beam is formed at the center position of the angles 321 and 322 where the path of the user # 2 exists, and the angle 311 where the path of the user # 1 exists, A null is formed at the center position of 312.

<Fifth Embodiment>
FIG. 13 is a block diagram of an array antenna transmission / reception apparatus according to the fifth embodiment of the present invention. In consideration of a plurality of paths having different propagation delay times in a multipath fading environment, in addition to the estimated signal arrival direction for each path. Thus, the received signal power of a plurality of paths is taken into account. According to this, for the desired wave, the main beam can be strengthened as the received signal power is larger, and for the interference wave, the null can be deepened as the received signal power is larger. In particular, it is effective in a system having a large correlation between uplink and downlink fading fluctuations, for example, time division duplex (TDD).

  In FIG. 13, in place of the signal arrival direction / reception signal power measurement units 119-1 to 119-K (FIG. 10), the signal arrival direction is estimated for a plurality of paths having different propagation delay times due to the multipath fading environment, and Received signal power / arrival direction measuring units 121-1 to 121-K having a function of measuring the received signal power of a plurality of paths are provided. Also, instead of the arrival direction / downlink reception SINR measurement value storage unit 110 (FIG. 10), the arrival direction / uplink reception that holds the signal arrival direction estimation value, reception signal power, and downlink reception SINR measurement value for each user path. A signal power / downlink received SINR measurement value storage unit 122 is provided. Further, the antenna weighting factor generators 111-1 to 111 -K receive the received signal with respect to the signal arrival direction of the mobile station to be transmitted based on the estimated signal arrival direction, the received signal power, and the downlink received SINR measurement value. An antenna weighting factor that increases the transmission antenna gain according to the power and downlink reception SINR measurement value and decreases the transmission antenna gain according to the reception signal power and downlink reception SINR measurement value with respect to the signal arrival direction of other mobile stations. The function is changed so that it is generated for each mobile station. Other configurations are the same as those of the fourth embodiment shown in FIG.

  FIG. 14 is a diagram illustrating calculation formulas of the antenna weight coefficient generation units 111-1 to 111-K in the fifth embodiment, and in addition to the signal arrival direction estimation value and the downlink reception SINR measurement value, the reception signal power is calculated. It is a formula that takes into account the calculation.

  FIG. 15 is a diagram showing an example of a transmission beam pattern in the fifth embodiment. In the transmission beam pattern for the user # 1 indicated by a solid line, the angles 311 and 312 where the path of the user # 1 exists are crossed. In addition, a main beam is formed near the angle 311 of the path with the large received signal power, and the angle 321 and 322 where the path of the user # 2 exists is deeper than the angle 321 of the path with the large received signal power (see FIG. 6). Nulls are formed). Similarly, in the transmission beam pattern for the user # 2 indicated by the broken line, the main beam is formed so as to cross the angles 321 and 322 where the path of the user # 2 exists and close to the angle 321 of the path having a large received signal power. At the same time, nulls are formed deeper (compared to FIG. 6) at the angles 311 and 312 where the path of the user # 1 exists than at the angle 311 of the path with the large received signal power.

<Sixth Embodiment>
FIG. 16 is a block diagram of an array antenna transmission / reception apparatus according to the sixth embodiment of the present invention. In consideration of multiple paths having different propagation delay times in a multipath fading environment, An antenna weighting coefficient is generated by excluding the signal arrival direction estimation value. In other words, if a null is directed to an interference wave in the direction of arrival of a nearby signal, the main beam in the direction of arrival of the desired wave is also expected to reduce the throughput, so interference within a predetermined proximity range is expected. By eliminating the estimated signal arrival direction of the wave from the calculation of the antenna weighting factor, the intensity of the main beam in the signal arrival direction of the desired wave is maintained.

  In FIG. 16, an inter-user signal arrival direction difference calculation unit 123 that calculates an angle difference between signal arrival directions from a plurality of mobile stations is newly provided in the arrival direction / uplink reception signal power / downlink reception SINR measurement value storage unit 122. It has been. Also, the antenna weighting factor generators 111-1 to 111 -K are interfering mobile stations that are close to each other in the signal arrival direction when the angle difference calculated by the inter-user signal arrival direction difference calculation unit 123 is equal to or less than a predetermined threshold. The function is changed so as to generate the antenna weighting coefficient by removing the estimated signal arrival direction. Other configurations are the same as those of the fifth embodiment shown in FIG.

  In addition, there are the following three patterns as a method for calculating the angle difference between the signal arrival directions from a plurality of mobile stations.

  Method 1: The signal arrival direction of the path having the maximum received signal power among the plurality of paths of the user serving as the interference wave and the signal arrival of the path having the maximum received signal power among the plurality of paths of the user serving as the desired wave A method to find the difference from the direction.

  Method 2: A method of obtaining a difference between an average signal arrival direction of a plurality of user paths serving as interference waves and an average signal arrival direction of a plurality of user paths serving as desired waves.

  Method 3: A method of obtaining the difference between the signal arrival direction of each of a plurality of user paths serving as interference waves and the signal arrival direction of each of a plurality of user paths serving as desired waves, and setting the smallest value among them.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

It is a block diagram of the array antenna transmission / reception apparatus concerning the 1st Embodiment of this invention. It is a figure which shows the calculation formula of the antenna weighting coefficient production | generation part in 1st Embodiment. It is a figure which shows the example of the transmission beam pattern in 1st Embodiment. It is a block diagram of the array antenna transmission / reception apparatus concerning the 2nd Embodiment of this invention. It is a figure which shows the calculation formula of the antenna weighting coefficient production | generation part in 2nd Embodiment. It is a figure which shows the example of the transmission beam pattern in 2nd Embodiment. It is a block diagram of the array antenna transmission / reception apparatus concerning the 3rd Embodiment of this invention. It is a figure which shows the calculation formula of the antenna weighting coefficient production | generation part in 3rd Embodiment. It is a figure which shows the example of the transmission beam pattern in 3rd Embodiment. It is a block diagram of the array antenna transmission / reception apparatus concerning the 4th Embodiment of this invention. It is a figure which shows the calculation formula of the antenna weighting coefficient production | generation part in 4th Embodiment. It is a figure which shows the example of the transmission beam pattern in 4th Embodiment. It is a block diagram of the array antenna transmission / reception apparatus concerning the 5th Embodiment of this invention. It is a figure which shows the calculation formula of the antenna weighting coefficient production | generation part in 5th Embodiment. It is a figure which shows the example of the transmission beam pattern in 5th Embodiment. It is a block diagram of the array antenna transmission / reception apparatus concerning the 6th Embodiment of this invention.

Explanation of symbols

101-1 to 101-M antenna 102-1 to 102-M duplexer 103-1 to 103-M RF receiving unit 104-1 to 104-M A / D conversion unit 105-1 to 105-M distributing unit 106-1 106-K Signal arrival direction estimation unit 107-1 to 107-K Antenna combining unit 108-1 to 108-K Demodulation unit 109-1 to 109-K Downlink reception SINR measurement value demodulation unit 110 Arrival direction / downlink reception SINR measurement Value storage unit 111-1 to 111 -K Antenna weight coefficient generation unit 112-1 to 112 -K Frame generation unit 113-1 to 113 -K Distribution unit 114-1 to 114 -K Multiply unit 115-1 to 115 -M Multiplexer 116-1 to 116 -M D / A converter 117-1 to 117 -M RF transmitter 118-1 to 118 -K Multipath combiner 119-1 to 11 -K signal arrival direction / reception signal power measurement unit 120-1 to 120-K average arrival direction calculation unit 121-1 to 121-K reception signal power / arrival direction measurement unit 122 arrival direction / uplink reception signal power / downlink reception SINR Measurement value storage unit 123 Inter-user signal arrival direction difference calculation unit

Claims (14)

A transmission device in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
A signal arrival direction estimation unit that estimates a signal arrival direction based on a received signal from the mobile station;
A downlink reception SINR measurement value demodulator that acquires downlink downlink SINR measurement values measured by the mobile station from the mobile station;
Based on the signal arrival direction estimation value estimated by the signal arrival direction estimation unit and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation unit, the downlink reception SINR with respect to the signal arrival direction of the mobile station to be transmitted An antenna weighting factor that increases the transmission antenna gain according to the measurement value and decreases the transmission antenna gain according to the downlink reception SINR measurement value with respect to the signal arrival direction of other mobile stations is determined for each mobile station to be transmitted. An antenna weight coefficient generation unit for generating ,
The antenna weighting coefficient generator, the mobile station k, the antenna weighting coefficient w (k), the steering vector a (k), the antenna correlation matrix and R _xx (k), the number of array antennas M, the antenna spacing d, the wavelength with respect to the downlink carrier frequency is λ _d , the unit matrix of M rows × M columns is I, the downlink received SINR measured by the mobile station k is (SINR) k, and the signal arrival direction estimation value from the mobile station k Is θ (k), and

An adaptive antenna array transmitter characterized by the following calculation . A transmission device in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
A signal arrival direction estimation unit for estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on the received signal from the mobile station;
A downlink reception SINR measurement value demodulator that acquires downlink downlink SINR measurement values measured by the mobile station from the mobile station;
Based on the signal arrival direction estimation value estimated by the signal arrival direction estimation unit and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation unit, the signal arrival direction of the plurality of paths of the mobile station to be transmitted is determined. On the other hand, an antenna that simultaneously increases the transmission antenna gain according to the downlink reception SINR measurement value and simultaneously decreases the transmission antenna gain according to the downlink reception SINR measurement value with respect to the signal arrival directions of the plurality of paths of the other mobile stations. An antenna weight coefficient generation unit that generates a weight coefficient for each mobile station to be transmitted;
The antenna weight coefficient generation unit sets the mobile station to k, the antenna weight coefficient to w _all (k), the steering vector to a _all (k), the antenna correlation matrix to R _{xx, all} (k), and the number of array antennas to M , Antenna spacing is d, wavelength for downlink carrier frequency is λ _d , unit matrix of M rows × M columns is I, downlink received SINR measured at mobile station k is (SINR) k, path from mobile station k Assuming that the estimated signal arrival direction for # ₁ is θ _l (k),

An adaptive antenna array transmitter characterized by the following calculation . A transmission device in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
Based on the received signal from the mobile station, a signal arrival direction estimation unit that estimates a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment and measures a received signal power of each of the plurality of paths. When,
A downlink reception SINR measurement value demodulator that acquires downlink downlink SINR measurement values measured by the mobile station from the mobile station;
Based on the signal arrival direction estimation value estimated by the signal arrival direction estimation unit and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation unit, the received signal power among the plurality of paths of the mobile station to be transmitted The transmission antenna gain is increased according to the downlink received SINR measurement value with respect to the signal arrival direction of the path with the maximum received signal, and the signal arrival direction of the path with the maximum received signal power among the plurality of paths of the other mobile stations An antenna weighting factor generating unit that generates an antenna weighting factor for reducing a transmission antenna gain according to a downlink reception SINR measurement value for each mobile station to be transmitted,
The antenna weighting coefficient generator, the mobile station k, the antenna weighting coefficient w _max (k), the steering vector a _max (k), and an antenna correlation matrix R _xx, and _max (k), the number of array antenna M , Antenna spacing is d, wavelength with respect to downlink carrier frequency is λ _d , unit matrix of M rows × M columns is I, downlink received SINR measured at mobile station k is (SINR) k, reception from mobile station k Assuming that the signal arrival direction of the path with the maximum signal power is θ _max (k),

An adaptive antenna array transmitter characterized by the following calculation . A transmission device in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
A signal arrival direction estimation unit for estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on the received signal from the mobile station;
An average arrival direction calculation unit that calculates an average arrival direction of the plurality of paths from the signal arrival direction estimation value estimated by the signal arrival direction estimation unit;
A downlink reception SINR measurement value demodulator that acquires downlink downlink SINR measurement values measured by the mobile station from the mobile station;
Based on the signal arrival direction estimation value estimated by the signal arrival direction estimation unit and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation unit, an average signal of the plurality of paths of the mobile station to be transmitted The transmission antenna gain is increased according to the downlink reception SINR measurement value with respect to the arrival direction, and the transmission antenna gain according to the downlink reception SINR measurement value with respect to the average signal arrival direction of the plurality of paths of the other mobile stations. An antenna weighting factor generator that generates an antenna weighting factor for each mobile station to be transmitted,
The antenna weighting coefficient generator, the mobile station k, the antenna weighting coefficient w _avg (k), the steering vector a _avg (k), and an antenna correlation matrix R _xx, and _avg (k), the number of array antenna M , Antenna interval is d, wavelength with respect to downlink carrier frequency is λ _d , unit matrix of M rows × M columns is I, downlink received SINR measured at mobile station k is (SINR) k, average from mobile station k _Assuming that the typical signal arrival direction is θ _avg (k),

An adaptive antenna array transmitter characterized by the following calculation . A transmission device in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
Based on the received signal from the mobile station, a signal arrival direction estimation unit that estimates a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment and measures a received signal power of each of the plurality of paths. When,
A downlink reception SINR measurement value demodulator that acquires downlink downlink SINR measurement values measured by the mobile station from the mobile station;
Based on the signal arrival direction estimation value estimated by the signal arrival direction estimation unit and the downlink reception SINR measurement value acquired by the downlink reception SINR measurement value demodulation unit, the antenna weighting factor is determined according to the received signal power of the plurality of paths. An antenna weight coefficient generation unit that generates each mobile station to be transmitted,
The antenna weighting coefficient generator, the mobile station k, the antenna weighting coefficient w _'all (k), the steering vector a' _all (k), the antenna correlation matrix and R _xx (k), the number of array antenna M , Antenna spacing is d, wavelength for downlink carrier frequency is λ _d , unit matrix of M rows × M columns is I, downlink received SINR measured by mobile station k is (SINR) k, path from mobile station k Assuming that the estimated signal arrival direction of #l is θ _l (k) and the uplink received signal power measurement value of path #l from the mobile station k is P _l (k),

An adaptive antenna array transmitter characterized by the following calculation .   The downlink reception SINR measurement value demodulating section demodulates the downlink reception SINR measurement value after combining the signals of the plurality of paths for each of the mobile stations. The adaptive antenna array transmitter described. A signal arrival direction difference calculation unit between users for calculating an angle difference between signal arrival directions from the plurality of mobile stations,
The antenna weighting factor generating unit generates the antenna weighting factor by excluding the signal arrival direction estimation value of the interfering mobile station in the proximity of the signal arrival direction when the calculated angle difference is equal to or less than a predetermined threshold. The adaptive antenna array transmitter according to any one of claims 1 to 6. A transmission method in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
A signal arrival direction estimation step of estimating a signal arrival direction based on a received signal from the mobile station;
A downlink reception SINR measurement value demodulating step of acquiring a downlink reception SINR measurement value of a downlink measured by the mobile station from the mobile station;
Based on the estimated signal arrival direction estimation value and the acquired downlink reception SINR measurement value, the transmission antenna gain is increased according to the downlink reception SINR measurement value with respect to the signal arrival direction of the mobile station to be transmitted, and other mobile stations antenna weighting coefficient for reducing the transmit antenna gain in response to the downlink reception SINR measurements to the signal direction of arrival of the, and an antenna weight coefficient generation step of generating for each mobile station to be transmitted,
In the antenna weighting factor generation step, the mobile station is k, the antenna weighting factor is w (k), the steering vector is a (k), the antenna correlation matrix is _Rxx (k), the number of array antennas is M, and the antenna interval is d, the wavelength with respect to the downlink carrier frequency is λ _d , the unit matrix of M rows × M columns is I, the downlink received SINR measured by the mobile station k is (SINR) k, and the signal arrival direction estimation value from the mobile station k Is θ (k), and

Adaptive antenna array transmission method and calculating by.   A transmission method in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
  A signal arrival direction estimation step for estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on the received signal from the mobile station;
  A downlink reception SINR measurement value demodulating step of acquiring a downlink reception SINR measurement value of a downlink measured by the mobile station from the mobile station;
  Based on the estimated signal arrival direction estimate and the acquired downlink reception SINR measurement value, the transmission antenna gain is simultaneously increased according to the downlink reception SINR measurement value for the signal arrival directions of the multiple paths of the mobile station to be transmitted. The antenna weights for each mobile station to be transmitted generate an antenna weighting factor that simultaneously decreases the transmission antenna gain according to the downlink received SINR measurement value with respect to the signal arrival directions of the plurality of paths of the other mobile stations. A coefficient generation process,
In the antenna weighting factor generating step, k is set as the mobile station and w is set as the antenna weighting factor. _all (k) the steering vector a _all (k), the antenna correlation matrix is R _{xx, all} (k), M is the number of array antennas, d is the antenna spacing, and λ is the wavelength for the downlink carrier frequency. _d , The unit matrix of M rows × M columns is I, the downlink received SINR measured at mobile station k is (SINR) k, and the signal arrival direction estimate of path # 1 from mobile station k is θ _l As (k),

An adaptive antenna array transmission method, characterized by:   A transmission method in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
  A signal arrival direction estimation step of estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on a received signal from the mobile station, and measuring a received signal power of each of the plurality of paths. When,
  A downlink reception SINR measurement value demodulating step of acquiring a downlink reception SINR measurement value of a downlink measured by the mobile station from the mobile station;
  Based on the estimated signal arrival direction estimation value and the acquired downlink reception SINR measurement value, the downlink reception SINR measurement is performed with respect to the signal arrival direction of the path having the maximum reception signal power among the plurality of paths of the mobile station to be transmitted. Increase the transmit antenna gain according to the value, and decrease the transmit antenna gain according to the downlink received SINR measurement value for the signal arrival direction of the path with the maximum received signal power among the multiple paths of the other mobile stations An antenna weighting factor generating step for generating an antenna weighting factor for each mobile station to be transmitted,
In the antenna weighting factor generating step, k is set as the mobile station, and w _max (k) the steering vector a _max (k), the antenna correlation matrix is R _{xx, max} (k), M is the number of array antennas, d is the antenna spacing, and λ is the wavelength for the downlink carrier frequency. _d , The unit matrix of M rows × M columns is I, the downlink received SINR measured at mobile station k is (SINR) k, and the signal arrival direction of the path with the maximum received signal power from mobile station k is θ _max As (k),

An adaptive antenna array transmission method, characterized by:   A transmission method in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
  A signal arrival direction estimation step for estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on the received signal from the mobile station;
  An average arrival direction calculation step of calculating an average arrival direction of the plurality of paths from the estimated signal arrival direction estimation value;
  A downlink reception SINR measurement value demodulating step of acquiring a downlink reception SINR measurement value of a downlink measured by the mobile station from the mobile station;
  Based on the estimated signal arrival direction estimation value and the acquired downlink reception SINR measurement value, the transmission antenna gain according to the downlink reception SINR measurement value for the average signal arrival direction of the plurality of paths of the mobile station to be transmitted And an antenna weighting factor for decreasing the transmission antenna gain in accordance with the downlink received SINR measurement value for each of the average signal arrival directions of the plurality of paths of the other mobile stations for each mobile station to be transmitted. An antenna weight coefficient generation step for generating,
In the antenna weighting factor generating step, k is set as the mobile station and w is set as the antenna weighting factor. _avg (k), steering vector a _avg (k), the antenna correlation matrix is R _{xx, avg} (k), the number of array antennas is M, the antenna interval is d, and the wavelength with respect to the downlink carrier frequency is λ. _d , The unit matrix of M rows × M columns is I, the downlink received SINR measured at mobile station k is (SINR) k, and the average signal arrival direction from mobile station k is θ _avg As (k),

An adaptive antenna array transmission method, characterized by:   A transmission method in a wireless transmission system in which a plurality of antennas are arranged in an array and signal transmission is performed simultaneously with a plurality of mobile stations,
  A signal arrival direction estimation step of estimating a signal arrival direction for each of a plurality of paths having different propagation delay times due to a multipath fading environment based on a received signal from the mobile station, and measuring a received signal power of each of the plurality of paths. When,
  A downlink reception SINR measurement value demodulating step of acquiring a downlink reception SINR measurement value of a downlink measured by the mobile station from the mobile station;
  An antenna weighting factor generating step for generating an antenna weighting factor for each mobile station to be transmitted, based on the estimated signal arrival direction estimation value and the acquired downlink received SINR measurement value, according to the received signal power of the plurality of paths; With
In the antenna weighting factor generation step, k is set as the mobile station and w ′ as the antenna weighting factor. _all (k) the steering vector a ′ _all (k), the antenna correlation matrix is R _xx (k), the number of array antennas is M, the antenna interval is d, and the wavelength with respect to the downlink carrier frequency is λ. _d , M row × M column unit matrix is I, downlink received SINR measured at mobile station k is (SINR) k, and signal arrival direction estimate of path # 1 from mobile station k is θ _l (k) The uplink received signal power measurement value of path #l from mobile station k is P _l As (k),

An adaptive antenna array transmission method, characterized by: The downlink reception SINR measurement value demodulation step demodulates the downlink reception SINR measurement value after combining the signals of the plurality of paths for each mobile station. The adaptive antenna array transmission method described.   The inter-user signal arrival direction difference calculating step for calculating the angle difference of the signal arrival directions from the plurality of mobile stations,
  The antenna weighting factor generating step generates an antenna weighting factor by excluding a signal arrival direction estimation value of an interfering mobile station close to the signal arrival direction when the calculated angle difference is equal to or less than a predetermined threshold value. The adaptive antenna array transmission method according to any one of claims 8 to 13.

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