JP2009159292A - Base station apparatus, radio communication system, and radio transmission method - Google Patents

Abstract

When transmitting a signal in a transmission band including a specific band used in another system, interference between base stations and terminals constituting the own system is suppressed while suppressing interference given to a radio station of the other system. Suppress communication degradation.
A subcarrier mapping unit 102 performs band allocation so that a signal of the entire transmission band is transmitted from a single antenna 108-1, and a subcarrier mapping unit 103 transmits other antennas 108-2 to 108-n. And weighting between antennas so that the directivity control weight generation and multiplication unit 106 has null directivity in the direction in which the radio station of another system exists. Apply processing. As a result, even when the radio station of the other system and the terminal of the own system exist in the same direction, the communication between the base station and the terminal constituting the own system is suppressed while suppressing interference given to the radio station of the other system. Deterioration can be suppressed.
[Selection] Figure 2

Description

  In the present invention, when a transmitting station of the first wireless communication system transmits a signal of a transmission band including a specific band used in the second wireless communication system, the transmission to the wireless station of the second wireless communication system is performed. The present invention relates to a technology that enables frequency sharing among a plurality of wireless communication systems by suppressing interference.

  In a mobile communication system (for example, a mobile phone system) that performs high-speed transmission, a wide wireless communication frequency bandwidth is required. Therefore, when constructing such a mobile communication system, it is necessary to ensure a wide frequency band.

  In general, in mobile communication, since it is assumed that the terminal moves, a frequency band below the microwave band is a candidate. However, frequencies below the microwave band are generally already used in existing systems such as fixed microwave communication systems and satellite communication systems. Therefore, in order to ensure a wide frequency band, the system must be configured so as not to interfere with these existing wireless communication systems.

  An example of a frequency band in which a plurality of systems coexist is an ISM band represented by a 2.45 GHz band, for example. In this frequency band, carrier sense is generally used. If it is found by carrier sense that other coexisting radio communication systems do not use the desired frequency band, the system can perform radio communication using that frequency band.

  However, in the mobile phone system, since it is necessary to provide a service constantly and in a plane, it is not possible to share a frequency band in time like the ISM band. In addition, TDMA and CDMA are difficult to introduce because they are different systems.

  Thus, spatial multiplexing (SDMA) using antenna directivity is a promising candidate for frequency sharing technology between such heterogeneous systems.

  For example, in a communication area of a mobile communication system composed of a base station (hereinafter also referred to as BTS) and a mobile station (hereinafter also referred to as MS), a band that overlaps a part of the band of this mobile communication system A case where there is a satellite system ground station (hereinafter also referred to as ES) to be used will be described.

  In the satellite system ground station ES, a high gain aperture antenna such as a parabolic antenna is directed to the satellite. In practice, a sharp beam (usually about a half-value angle of about 2 to 3 °) is directed toward the satellite. In the other direction, the reception level is attenuated by about 50 dB compared to the peak direction of the beam due to the side lobe or null directivity.

  Consider a case where a mobile communication system such as a mobile phone system, which is a system different from the satellite communication system, is operated using a band including the band of the satellite communication system. When using the current technology, a base station of a mobile communication system transmits, for example, omni directivity or sector directivity such as 120 ° or 90 °.

  However, even if directional transmission is performed in such a direction as to avoid the satellite system ground station ES using such directivity transmission technology, the received power from the satellite in the satellite system ground station ES is very small. Interference from a communication system base station is a major problem. As described above, the satellite system ground station ES is designed to have a low gain except in the beam direction. However, since the received signal strength from the space station is very low, the base of the mobile communication system is in the sidelobe direction. Even if there is a station, the signal from this base station becomes interference.

  Therefore, in the base station of the mobile communication system, by performing adaptive array antenna control or amplitude / phase weighting between the base stations on a predetermined subcarrier used in the satellite system ground station ES, the satellite system ground station ES It is conceivable that null point control is performed so that the interference power to the band used by the wireless communication device is equal to or less than a predetermined value, that is, the SDMA technique is applied to reduce interference.

  In the above description, the satellite communication system is given as an example of a radio communication system coexisting with a mobile communication system because it is a typical example in that there is no other communication system that can replace the satellite communication system. The same can be considered between different types of wireless communication systems.

Examples of conventional SDMA include directivity control using an array antenna described in Non-Patent Document 1. In this document, as shown in FIG. 14A, directivity control as shown in FIG. 14B is performed by multiplying a transmission signal (transmission data) by predetermined weights W0 and W1 and transmitting it by a plurality of antennas. Thereby, as shown in FIG. 15, directivity is directed toward the mobile station MS and null directivity is directed toward the satellite system ground station ES. By using this method, it is possible to suppress interference from the base station BTS of the mobile communication system to the satellite system ground station ES.
Nobuyoshi Kikuma "Adaptive signal processing by array antenna" Science and Technology Publishing Co., Ltd.

  However, in the conventional method, as shown in FIG. 16, when the mobile station MS exists in the direction of the satellite system ground station ES as viewed from the base station BTS of the mobile communication system, null directivity is also applied to the mobile station MS. Therefore, communication of the mobile communication system (that is, communication between the base station BTS and the mobile station MS of the mobile communication system) deteriorates.

  An object of the present invention is to solve the above-described conventional problem, and when transmitting a signal of a transmission band including a specific band used in another system, while suppressing interference given to a radio station of the other system, This is to suppress deterioration of communication between the base station and the terminal constituting the own system.

  One aspect of the base station apparatus of the present invention is a base station apparatus that transmits a signal in a transmission band including a specific band used in another system, the first and second antennas, and the first antenna A band allocating unit that allocates the signal of the transmission band to the antenna and allocates the signal of the specific band to the second antenna, and a signal allocated to the first and second antennas by the band allocating unit. And a weighting means for weighting with.

  In one aspect of the wireless transmission method of the present invention, a first band signal is transmitted from a single antenna, and a second band signal forming a part of the first band is The step of transmitting from a plurality of antennas including a single antenna, the signal of the first band, and the signal of the second band are weighted between the antennas, thereby directing the signal of the second band. Controlling sex.

  According to the present invention, with a very simple configuration, for a specific band, a directivity signal in which a null is directed in a direction where a radio station of another system exists is formed, and the transmission band of the own system excluding the specific band Can form an omnidirectional signal. In other words, it is possible to control directivity only in a band used by a radio station of another system. As a result, even when the wireless station of the other system and the terminal of the own system are in the same direction as seen from the base station, the terminal of the own system has a good signal in the band not used by the wireless station of the other system. Can be received. That is, it is possible to suppress the deterioration of communication between the base station and the terminal constituting the own system while suppressing the interference given to the radio station of the other system.

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

(Embodiment 1)
First, before describing the configuration of the present embodiment, an example of a band used between different systems assumed in the present embodiment will be described.

  FIG. 1 shows an example of a band used between different systems, and shows a relationship between an IMT-Advanced communication band studied as a next-generation mobile communication system and a band used by a fixed satellite service (FSS). Is. As can be seen from FIG. 1, a specific band in the IMT-Advanced communication band interferes with the fixed satellite service FSS.

  In the present embodiment, for example, a second wireless communication system (for example, IMT-Advanced) is secured between different types of wireless communication systems having the relationship shown in FIG. 1 while ensuring communication of the first wireless communication system (for example, IMT-Advanced). For example, a system capable of suppressing interference with a fixed satellite service (FSS) is presented.

  FIG. 2 shows a configuration example of a base station of the mobile communication system according to Embodiment 1 of the present invention. FIG. 2 shows an example in which the present invention is applied to an OFDM (Orthogonal Frequency Division Multiplex) scheme.

  2, a base station 100 of a mobile communication system includes a transmission data generation unit 101, a subcarrier mapping unit (all bands) 102, a subcarrier mapping unit (specific band) 103, and a fast inverse Fourier transform (IFFT) unit. 104, a CP (Cyclic Prefix) insertion unit 105, a directivity control weight generation / multiplication unit 106, an RF transmission unit 107, and a transmission antenna 108.

  The transmission data generation unit 101 generates transmission data, and sends the generated transmission data to the subcarrier mapping unit (all bands) 102 and the subcarrier mapping unit (specific band) 103. As a result, the same transmission data is input to the subcarrier mapping unit (all bands) 102 and the subcarrier mapping unit (specific band) 103.

  A subcarrier mapping unit (all bands) 102 maps transmission data to all bands. This is shown in FIG. 3A. The subcarrier mapping unit (full band) 102 maps transmission data to all subcarriers (that is, all bands) shown in FIG. 3A.

  The subcarrier mapping unit (specific band) 103 maps the same transmission data as the subcarrier mapping unit (all bands) 102 by the same mapping method. However, the band other than the band used by another system terminal (that is, the specific band) is forcibly set to 0. This is shown in FIG. 3B. The specific band indicated as “directional subcarrier” in FIG. 3B is the same band as the band indicated as “directional subcarrier” in FIG. 3A. The subcarrier mapping unit (specific band) 103 is the same as the transmission data arranged in the band indicated as “directional subcarrier” in FIG. 3A in the specific band indicated as “directional subcarrier” in FIG. 3B. The transmission data of is arranged.

  The IFFT unit 104 includes an IFFT unit 104-1 and an IFFT unit 104-2. IFFT section 104-1 forms an OFDM signal by performing fast inverse Fourier transform on the data formed in subcarrier mapping section (full band) 102. IFFT section 104-2 forms an OFDM signal by performing fast inverse Fourier transform on the data formed in subcarrier mapping section (specific band) 103.

  The CP insertion unit 105 includes a CP insertion unit 105-1 and a CP insertion unit 105-2. CP insertion section 105-1 inserts a CP (Cyclic Prefix) into the OFDM signal output from IFFT section 104-1. CP insertion section 105-2 inserts a CP (Cyclic Prefix) into the OFDM signal output from IFFT section 104-2.

  The directivity control weight generation / multiplication unit 106 includes directivity control weight generation / multiplication units 106-1 to 106-n. The directivity control weight generation / multiplication unit 106-1 receives the OFDM signal output from the CP insertion unit 105-1. On the other hand, the OFDM signal output from the CP insertion unit 105-2 is input to the directivity control weight generation and multiplication units 106-2 to 106-n.

  When the other system terminal is installed, the directivity control weight generating and multiplying unit 106 obtains the direction of the other system terminal viewed from the base station 100 of the mobile communication system, and sets the direction of the other system terminal. A directivity control weight is generated such that a null is directed toward the system terminal, and this weight is multiplied by the OFDM signal into which the CP is inserted by the CP insertion unit 105. The directivity control weight may be generated by a general method as described in Non-Patent Document 1.

  The RF transmission unit 107 includes RF transmission units 107-1 to 107-n. The RF transmitters 107-1 to 107-n perform digital-analog conversion processing and up-conversion to a radio frequency band on the signals obtained by multiplying the directivity control weights by the directivity control weight generation and multiplication units 106-1 to 106-n. Wireless transmission processing such as processing is performed.

  The transmission antenna unit 108 includes transmission antennas 108-1 to 108-n. The transmission antennas 108-1 to 108-n transmit signals obtained by the RF transmission units 107-1 to 107-n.

  FIG. 4 shows the directivity of the transmission signal obtained by the base station 100. The solid line in the figure indicates the directivity of the band used by the other system (that is, the specific band), and the alternate long and short dash line in the figure indicates the directivity of the band excluding the band that is used by the other system (that is, the specific band). Showing gender.

  As can be seen from FIG. 4, the signal in the specific band is formed with directivity such that the null is directed in the direction in which the terminal of the other system exists, so that the interference of the signal from the base station 100 is suppressed in the terminal of the other system. Is done.

  On the other hand, since signals in a band excluding a specific band are omnidirectional, even if the terminal of the mobile communication system is located in the same direction as the terminal of another system exists, the terminal of the mobile communication system Can receive a signal in a band other than the specific band with sufficient power, so that communication with the base station 100 can be ensured.

  FIG. 5 shows the specific state. FIG. 5 shows a case where the mobile station 200 of the mobile communication system is located in the direction of another system terminal (for example, a satellite system ground station) 300 when viewed from the base station 100.

  Since the base station 100 controls the directivity of the band used by the other system terminal 300 so that the null directivity is directed toward the other system terminal 300, the other system terminal 300 Not subject to interference.

  On the other hand, since the base station 100 performs omnidirectional control on a band other than the band used by the other system terminal 300, the mobile station 200 satisfactorily receives a signal in this band from the base station 100. be able to. Incidentally, the signal in the band in which the omnidirectional control is performed is an out-of-band signal used for the other system terminal 300, and thus does not cause interference.

  As described above, according to the present embodiment, when transmitting a signal in a transmission band including a specific band used in another system, the signal in the transmission band is transmitted from a single antenna. A signal in a specific band is transmitted from the antennas of the other antennas, and weighting processing is performed between the antennas so that the null directivity is directed in the direction in which the radio stations of other systems exist.

  As a result, with a very simple configuration, for a specific band, a directional signal is formed in which nulls are directed in the direction in which radio stations of other systems exist, and there is no transmission band of the own system excluding the specific band. A directional signal can be formed. As a result, with a very simple configuration, it is possible to suppress the deterioration of communication between the base station and the terminal constituting the own system while suppressing the interference given to the radio station of the other system.

  In this embodiment, a case where signals in a specific band are transmitted from a plurality of antennas 108-2 to 108-n has been described as an example. However, signals in a specific band may be transmitted from a single antenna.

  FIG. 6 shows a basic configuration diagram of the present embodiment. The same transmission data is input to the bandwidth allocation unit 1 and the bandwidth allocation unit 2. The band allocation unit 1 allocates transmission data to all bands (for example, the IMT-Advanced communication band in FIG. 1). The band allocation unit 2 allocates transmission data to a specific band (for example, a band used by the fixed satellite service in FIG. 1). The signals to which bands are allocated by the band allocation unit 1 and the band allocation unit 2 are weighted between the antennas by using the weighting coefficients W0 and W1 by the weighting unit 120, and then supplied to the antennas AN1 and AN2.

  With the configuration in FIG. 6, the signal in the specific band is weighted and transmitted from the antennas AN1 and AN2, so that a null directivity is formed in a desired direction. On the other hand, a signal in a band excluding a specific band is transmitted from only the antenna AN1, and thus is a non-directional signal regardless of weighting. Therefore, an operation similar to that of the above-described embodiment can be performed.

  Incidentally, as shown in FIG. 7, the present invention can be realized simply by adding the configuration of the retrofit portion 140 to the existing portion 130. The retrofit portion 140 only needs to include a bandpass filter (BPF) 141 that allows only a specific band to pass, a weighting unit 142, and an antenna 143.

(Embodiment 2)
FIG. 8 in which the same reference numerals are assigned to corresponding parts as in FIG. 2 shows the system configuration of the mobile communication system according to the second embodiment. The mobile communication system in FIG. 8 includes a base station 400 and a beacon transmission station 500.

  Base station 400 includes reception antenna 401, RF reception unit 402, and other system terminal direction estimation unit 403 in addition to the configuration of base station 100 of the first embodiment, and thereby generates directivity control weights and The direction of another system terminal to be input to the multiplication unit 106 is obtained.

  The beacon transmission station 500 is installed in the vicinity of the other system terminal 300 (FIG. 5), and includes a beacon generation unit 501, an RF transmission unit 502, and a transmission antenna 503.

  The beacon generation unit 501 generates a beacon signal for direction estimation by the base station 400. The RF transmission unit 502 performs wireless transmission processing such as digital-analog conversion processing and up-conversion processing to a radio frequency band on the beacon signal generated by the beacon generation unit 501, and transmits the signal after wireless processing via the transmission antenna 503. Send.

  The base station 400 performs predetermined radio processing such as down-conversion processing to the baseband band and analog-digital conversion processing on the signal received from the receiving antenna 401 in the RF receiving unit 402, and outputs the processed signal to the other Send to system terminal direction estimation section 403.

  The other system terminal direction estimation unit 403 estimates the direction of the beacon transmitting station 500, that is, the direction of the other system terminal 300 (FIG. 5) using the received beacon signal, and generates and multiplies the directivity control weight result. To the unit 106. The direction may be estimated by a general method as described in Non-Patent Document 1, for example.

  By using the configuration of the present embodiment, the same effect as that of the first embodiment can be obtained even if direction information is not obtained when the other system terminal 300 is installed.

(Embodiment 3)
FIG. 9 in which the same reference numerals are assigned to corresponding parts as in FIG. 2 shows the system configuration of the mobile communication system according to the third embodiment. The mobile communication system in FIG. 9 includes a base station 600 and a position estimation station 700.

  Base station 600 includes receiving antenna 601, RF receiving unit 602, GPS information demodulating unit 603, and terminal direction estimating unit 604 in addition to the configuration of the first embodiment, thereby generating directivity control weights. The direction of the other system terminal to be input to the multiplication unit 106 is obtained.

  The position estimation station 700 is installed in the vicinity of the other system terminal 300 (FIG. 5) and includes a GPS antenna 701, a GPS information generation unit 702, an RF transmission unit 703, and a transmission antenna 704.

  The GPS information generation unit 702 generates GPS information representing the position based on the signal received from the GPS antenna 701. The RF transmission unit 703 performs radio transmission processing such as digital-analog conversion processing and up-conversion processing to a radio frequency band on the GPS information generated by the GPS information generation unit 702, and the signal after the radio processing is transmitted via the transmission antenna 704. To send.

  The base station 600 performs predetermined radio processing such as down-conversion processing to the baseband band and analog-digital conversion processing on the signal received from the receiving antenna 601 in the RF receiving unit 602, and the processed signal is transmitted to the GPS The data is sent to the information demodulator 603.

  The GPS information demodulator 603 generates the position of the position estimation station 700 from the GPS information, that is, the position information of the other system terminal 300 (FIG. 5).

  The other system terminal direction estimation unit 604 based on the GPS information determines the direction of the other system terminal 300 (FIG. 5) from the positional information of the other system terminal generated by the GPS information demodulation unit 603 and the positional relationship of the base station 600. The estimation result is sent to the directivity control weight generation and multiplication unit 106.

  By using the configuration of the present embodiment, the same effect as in the first embodiment can be obtained even when direction information cannot be obtained when the other system terminal 300 is installed or when the other system terminal 300 moves. Can do.

(Embodiment 4)
FIG. 10, in which the same reference numerals are assigned to the parts corresponding to FIG. 2, shows the configuration of the base station according to the fourth embodiment. FIG. 10 shows a configuration example when the present invention is applied to a single carrier system.

  Compared with base station 100 of Embodiment 1, base station 800 has subcarrier mapping section (all bands) 102, subcarrier mapping section (specific band) 103, IFFT section 104, and CP insertion section 105 deleted. A band-pass filter (BPF) unit 801 that passes only a band (specific band) used by another system terminal is added.

  The BPF unit 801 passes only the band (specific band) used by other system terminals out of the entire band of transmission data output from the transmission data generation unit 101, and transmits the band to the directivity control weight generation and multiplication unit 106. To do.

  The direction of the other system terminal, which is the input of the directivity control weight generation and multiplication unit 106, is determined by any of the methods in the first to third embodiments.

  By using the configuration of this embodiment, the same effect as that of Embodiment 1 can be obtained even in the single carrier system.

  Note that the band for directivity control can be adjusted by changing the pass band of the BPF unit 801.

(Embodiment 5)
FIG. 11 in which parts corresponding to those in FIG. 10 are assigned the same reference numerals shows the configuration of the base station according to the fifth embodiment. FIG. 11 shows a configuration example when the present invention is applied to a single carrier system.

  In the base station 900, the BPF unit 801 of the base station 800 of the fourth embodiment is changed to a passband switchable BPF unit 901.

  The passband switchable BPF unit 901 passes only a specific band out of the entire band of transmission data output from the transmission data generation unit 101 and sends it to the directivity control weight generation and multiplication unit 106. Since the passband switchable BPF unit 901 has a plurality of bandpass filters (BPF1 to BPFM) having different passbands as shown in FIG. 12, the bandpass filter to be used is selected from them. , The passband can be switched.

  The direction of the other system terminal, which is the input of the directivity control weight generation and multiplication unit 106, is determined by any of the methods in the first to third embodiments.

  By using the configuration of the present embodiment, even in the single carrier system, the same effect as in the first embodiment can be obtained, and in addition, the band for which directivity control is desired can be switched.

(Embodiment 6)
FIG. 13, in which the same reference numerals are assigned to corresponding parts as in FIG. 2, shows the system configuration of the mobile communication system according to the sixth embodiment. The mobile communication system in FIG. 13 includes a base station 1000 and a sensor station 1100.

  In base station 1000, directivity control weight generation and multiplication section 106 of base station 100 of Embodiment 1 is changed to directivity control weight multiplication section 1002, and known signal multiplexing section 1001, receiving antenna 1003, and RF receiving section are changed. 1004 and a directivity control weight demodulator 1005 are added. Further, in the known signal multiplexing unit 1001, since different signal patterns are multiplexed for each antenna 108 (108-1, 108-2-1 to 108-2-M), compared with the base station 100, the subcarrier mapping unit ( Specific bands) 103-1 to 103-M, IFFT sections 104-2-1 to 104-2-M, and CP insertion sections 105-2 to 105-2-M are transmitting antennas 108-1 to 108- There are as many as 2-M.

  The known signal multiplexing unit 1001 generates a different pattern for each of the transmission antennas 108-1 and 108-2-1 to 108-2-M, and multiplexes it with transmission data. For example, in the case of time division multiplexing, an OFDM symbol at a certain timing is set as a known signal.

  The directivity control weight multiplication unit 1002 multiplies the current weight by the weight correction value specified by the directivity control weight demodulation unit 1005, and multiplies the signal input from the CP insertion unit 105 as a new weight.

  The RF receiving unit 1004 performs predetermined radio processing such as down-conversion processing to the baseband and analog-digital conversion processing on the signal from the sensor station 1100 received from the receiving antenna 1003, and directs the processed signal. It is sent to the sex control weight demodulator 1005.

  The directivity control weight demodulator 1005 demodulates the directivity control weight correction value received from the sensor station 1100 and notifies the directivity control weight multiplier 1002 of the demodulated value.

  The sensor station 1100 is installed in the vicinity of the other system terminal 300 (FIG. 5), and includes a receiving antenna 1101, a known signal demodulator 1103, a directivity control weight generator 1104, a directivity control weight modulator 1105, an RF A transmission unit 1106 and a transmission antenna 1107 are included.

  The RF reception unit 1102 performs predetermined radio processing such as down-conversion processing to the baseband band and analog-digital conversion processing on the signal from the base station 1000 received from the receiving antenna 1101, and the processed signal is known. It is sent to the signal demodulator 1103.

  Known signal demodulation section 1103 demodulates the known signal multiplexed at base station 1000 and demodulates the complex channel values for each of transmitting antennas 108-1 and 108-1 to 108-2-M of base station 1000. Estimate based on a known signal.

  The directivity control weight generation unit 1104 obtains a directivity control weight correction value using the complex channel value input from the known signal demodulation unit 1103. An example of how to obtain the directivity control weight correction value will be described. For simplicity, it is assumed that the number of transmission antennas of the base station 1000 is two. Assume that the first and second complex channel values C1 and C2 of the transmission antenna are expressed by the following equations (1) and (2).

C1 = A1 × exp (jθ1) (1)
C2 = A2 × exp (jθ2) (2)

  The first and second directivity control weight correction values W1 and W2 of the transmission antenna are set, and the first directivity control weight correction value of the transmission antenna is fixed, that is, W1 = 1. At this time, W2 may be a value such that the following expression (3) is satisfied, and from this, expression (4) can be obtained.

C2 × W2 = −C1 (3)
W2 = −A1 / A2 × exp {j (θ1−θ2)} (4)

  By correcting the directivity control weight of the base station 1000 by this value, the signal level of the specific band from the base station 1000 in the sensor station 1100 can be reduced. That is, interference with other system terminal 300 (FIG. 5) can be reduced.

  Directivity control weight modulation section 1105 modulates the directivity control weight correction value obtained by directivity control weight generation section 1104 for transmission to base station 1000.

  The RF transmission unit 1106 performs radio transmission processing such as digital-analog conversion processing and up-conversion processing to a radio frequency band on the data modulated by the directivity control weight modulation unit 1105. The signal after the wireless processing is transmitted via the transmission antenna 1107.

  By using the configuration of the present embodiment, the directivity control weight can be generated by a general method as described in Non-Patent Document 1 because the arrangement of the transmission antennas 108 of the base station 1000 is irregular. Even if it is difficult, an accurate directivity control weight can be generated, so that the same effect as in the first embodiment can be obtained.

  The present invention is suitable for application to a wireless system in which a part of a band is shared between different types of systems, such as a relationship between an IMT-Advanced system that is a mobile communication standard and a fixed satellite service system.

The figure which shows the relationship between the communication band of IMT-Advanced which is the standard of a mobile communication system, and the use band of a fixed satellite service (FSS). FIG. 2 is a block diagram illustrating a configuration example of a base station according to the first embodiment. FIG. 3A is a diagram for explaining band allocation, FIG. 3A is a diagram showing a state of all bandwidth allocation, and FIG. 3B is a diagram showing a state of specific band allocation. The figure which shows the mode of directivity control by the base station of Embodiment 1 The figure which shows the mode of directivity control by the base station of Embodiment 1 The figure which shows the basic composition of the base station of Embodiment 1. The figure which shows the other structural example by Embodiment 1. FIG. Block diagram showing a system configuration of the second embodiment The block diagram which shows the system configuration | structure of Embodiment 3. Block diagram showing a configuration of a base station according to the fourth embodiment Block diagram showing a configuration of a base station according to the fifth embodiment The figure which shows the frequency characteristic of BPF section which can switch pass band Block diagram showing the system configuration of the sixth embodiment FIG. 14A is a diagram illustrating a directivity control by a conventional array antenna, FIG. 14A is a diagram illustrating a configuration example, and FIG. 14B is a diagram illustrating directivity. Diagram showing directivity control by conventional array antenna Diagram for explaining conventional issues

Explanation of symbols

100, 400, 600, 800, 900, 1000 Base station 102, 103 Subcarrier mapping unit 106 Directivity control weight generation and multiplication unit 108, AN1, AN2 Antenna 120 Weighting unit 500 Beacon transmission station 700 Position estimation station 1100 Sensor station

Claims (7)

A base station device that transmits a signal of a transmission band including a specific band used in another system,
First and second antennas;
Band allocating means for allocating the transmission band signal to the first antenna and allocating the specific band signal to the second antenna;
Weighting means for weighting signals assigned to the first and second antennas by the band assignment means between the antennas;
A base station apparatus comprising: The weighting unit performs weighting so that a signal in the specific band is directed toward a null in a direction in which a radio station of the other system exists.
The base station apparatus according to claim 1. First and second antennas;
Band allocating means for allocating a transmission band signal to the first antenna and allocating a signal of a part of the transmission band to the second antenna;
Weighting means for weighting signals assigned to the first and second antennas by the band assignment means between the antennas;
A base station apparatus having
A transmission radio station provided in the vicinity of a radio station of a different type of radio communication system from the radio communication system to which the base station device belongs;
Comprising
The weighting means of the base station device weights the signal of the specific band based on a signal from the transmitting wireless station so that a null is directed in a direction in which the wireless station of the other system exists.
Wireless communication system. The transmitting radio station is a beacon transmitting station that transmits a beacon signal.
The wireless communication system according to claim 3. The transmitting radio station transmits GPS information.
The wireless communication system according to claim 3. First and second antennas;
Band allocating means for allocating a transmission band signal to the first antenna and allocating a signal of a part of the transmission band to the second antenna;
Weighting means for weighting signals assigned to the first and second antennas by the band assignment means between the antennas;
A base station apparatus having
A sensor station that is provided in the vicinity of a radio station of a different type of radio communication system to which the base station apparatus belongs, and that measures a received signal level of a signal transmitted from the base station apparatus;
Comprising
The weighting means of the base station device performs weighting based on a signal from the sensor station so that a signal of the specific band is directed toward a direction in which a radio station of the other system exists.
Wireless communication system. A first band signal is transmitted from a single antenna, and a second band signal forming part of the first band is transmitted from a plurality of antennas including the single antenna. Steps,
Controlling the directivity of the signal in the second band by weighting the signal in the first band and the signal in the second band between antennas;
A wireless transmission method including:

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