CN1227840C - Wireless base station, direction control method of wireless base station - Google Patents

Abstract

A forced zero weight calculation unit (334) of a direction control unit (31) corresponding to a target mobile station whose direction is unknown among mobile stations that perform multiplexing calculates a forced zero weight for forming a pattern having the direction of the target mobile station as a zero point with respect to the direction of another mobile station, and a power-off weight calculation unit (335) of direction control units (32 to 34) corresponding to the other mobile stations calculates a power-off weight for forming a pattern that attenuates a transmission gain. A transmission signal adjusting section (350) of each direction control section transmits a signal to each mobile station through a directional pattern formed by the calculated weight, thereby ensuring an appropriate S/I ratio for a mobile station with unknown direction and realizing path division multiplexing.

Description

Wireless base station, direction control method of wireless base station

technical field

The present invention relates to a wireless base station communicating with multiple mobile stations by means of diameter division multiple access, a direction control method and a program of the wireless base station, and particularly relates to the direction control technology of the wireless base station.

Background technique

In recent years, with the increase of wireless information terminals including mobile phones, portable information communication devices, etc., social demands for efficient use of frequency resources have been increasing. Among the technologies answering this call is path division multiple access.

The so-called diameter division multiple access method refers to a method in which a wireless base station communicates with multiple mobile stations existing in different directions at the same time using a carrier wave of one frequency by using an antenna that has directions for both transmission and reception.

An adaptive array device is used as an antenna used in a radio base station of the radial division multiple access method. The adaptive array device has a plurality of antennas fixedly installed, and forms the transmission and reception pattern of the device as a whole by changing the amplitude and phase of the transmission and reception signals of each antenna.

More specifically, this device changes the amplitude and phase of signals received by each antenna for each antenna and adds the signals, and uses a pattern corresponding to the amount of change in the amplitude and phase (hereinafter referred to as weighting). Synthesize the received signal. Also, by sending out signals obtained by changing the amplitude and phase of the transmission signal for each antenna with the same weighting as the reception time, the signal is transmitted with the same pattern as the reception time.

The adaptive array device is described in detail in "Adaptive Signal Processing of Array Antenna" (Nobuyoshi Kikuma, Science and Technology Publishing).

The wireless base station forms an optimum pattern for each multiplexed mobile station using the adaptive array device. That is, the radio base station uses each of the multiplexed mobile stations as a desired mobile station, and forms a structure in which the transmission strength and reception sensitivity are increased in the direction of the desired mobile station (hereinafter referred to as beam alignment) and other mobile stations are aligned. The direction pattern that reduces the transmission strength and reception sensitivity (hereinafter referred to as zero alignment) in the direction.

In the adaptive array device, the main part of the process of forming the optimum pattern is nothing but the process of calculating the weights to provide the optimum pattern. The adaptive array device calculates the weighted optimal value according to the minimum mean square error (MMSE: Minimum Mean Square Error) method.

The MMSE method is based on the principle that the average value of the square of the difference between the signal sent by the desired mobile station and the combined received signal is the smallest weight to form the optimal pattern for the desired mobile station. value method.

The adaptive array device based on the MMSE method calculates the optimal value of weights by using the prior knowledge of the signal content or modulation method during signal reception to estimate and copy the signal sent by the mobile station, and calculates the weighted value according to the specified unit time. For example, each symbol time of a signal sequentially corrects the preceding weighting to reduce the average value of the square of the difference between the signal (referred to as a reference signal) and the received signal.

Also, during a transmission period subsequent to a signal reception period, the apparatus transmits a signal with the same pattern as at the end of the reception period using the weighting at the end of the reception period.

Fig. 5 shows the direction diagram formed by making one mobile station a desired mobile station and the other an undesired mobile station by using the existing direction control method when two mobile stations are multiplexed by path division. In this figure, 900 is a wireless base station, 901 and 902 are mobile stations, 911 is a pattern formed for the mobile station 901, and 912 is a pattern formed for the mobile station 902.

In this way, the radio base station that communicates with a plurality of mobile stations using the path division multiple access method forms an optimum pattern for each multiplexed mobile station. Accordingly, the radio base station realizes efficient use of frequency resources while maintaining appropriate communication quality with each mobile station.

However, since the adaptive array device uses the response vector calculated from the received signal to control the direction, it cannot control the direction pattern for a mobile station that has never received a signal, that is, a mobile station that has not obtained response vector information.

Therefore, when an existing wireless base station using this device communicates with a new mobile station by means of path division multiplexing, it is necessary to first receive an uplink signal sent by the mobile station to calculate a response vector. Since the base station transmits downlink signals of path division multiplexing, there is a problem that the communication sequence is restricted.

Also, after the response vector is calculated from the uplink signal received from the mobile station, when the mobile station moves, an error occurs in the direction of the mobile station indicated by the response vector. Especially when a long time has elapsed after calculating the response vector or the mobile station moves quickly, if the downlink signal of path division multiplexing is continuously transmitted using the transmission pattern formed based on the last calculated response vector, the signal will not arrive. The desired mobile station also arrives as an interfering signal with respect to the moving undesired mobile station, so there is a problem that the communication quality of the path division multiplexing communication is deteriorated due to the generation of noise and mixed signals.

For example, when a mobile station is handed over to another radio base station, the radio base station does not receive an uplink signal from the mobile station but transmits a signal called a return color burst signal at a predetermined timing, which causes the above-mentioned problem.

In addition, as in the packet communication mode, the communication sequence of receiving an uplink signal from a mobile station in a certain time-division time slot, using that time slot to communicate with other mobile stations, and then sending a downlink signal to the previous mobile station is defined. In the allowed protocol, the above problems will also arise.

Contents of the invention

In order to solve the above-mentioned problems, an object of the present invention is to provide communication in which the limitation of the communication sequence is eliminated and the path-division multiplexing communication is improved by efficiently performing path-division multiplexing on a mobile station whose direction is unknown from a radio base station. A quality wireless base station and a direction control method for the wireless base station.

The radio base station of the present invention is a radio base station that communicates with a plurality of mobile stations by using a radial division multiple access method by using an adaptive array device. signal to calculate a response vector representing the relative direction of each mobile station; a determination unit that determines a target mobile station whose direction is unknown from the wireless base station among the plurality of mobile stations; a first calculation unit that calculates a target mobile station for all The target mobile station forms the parameters of the direction diagram with only the direction indicated by the response vector calculated for other mobile stations except the target mobile station as the zero point; the first control unit forms the parameters for A transmission pattern of the target mobile station; and a second control unit that changes transmission output to other mobile stations to a predetermined value simultaneously with the start of transmission to the target mobile station.

Based on these structures, since the wireless base station of the present invention transmits a signal to the target mobile station by means of the forced zero pattern in which a zero point is set in the direction of the other mobile station and transmits a signal to the other mobile station by means of the power-off pattern in which the transmission gain is reduced, Therefore, it is possible to ensure an appropriate strength ratio between the desired signal and the undesired signal in the direction of each mobile station, and it is possible to perform path division multiplexing communication while maintaining appropriate communication quality with a target mobile station whose direction is unknown.

Furthermore, since the forced zero pattern can be formed without receiving a signal from the target mobile station in advance, it is possible to eliminate the limitation of the communication sequence placed at the start of the conventional multiplexing.

In addition, the wireless base station may further include a measuring unit that measures the strength of a signal received from a mobile station, and the determining unit may determine that (a) the received signal has not been obtained for a certain period or more, (b) the error rate of the received signal is greater than a predetermined value, (c) the strength of the received signal is smaller than a threshold value, or (d) the mobile station whose fading speed is higher than a predetermined value is determined as the target mobile station.

According to this configuration, since the radio base station specifies the target mobile station even when the direction is determined to be unknown or the reliability of the direction is low, it is possible to more accurately determine the state in which the above-described direction control should be performed.

In addition, the second control unit may correspond to the error rate, intensity, and modulation speed of the signal received from the control target mobile station, the fading speed of the control target mobile station, and the reception of the mobile station notified from the control target mobile station. One of the error rates that will send output is increased or decreased from the specified value.

According to this configuration, since the attenuation amount is adjusted including the condition that the communication quality is judged to be deteriorated due to the decrease of the transmission gain with respect to the mobile station communicating with the power-off pattern, it can be expected to improve the communication quality with the power-off target mobile station. .

The direction control method in a radio base station of the present invention is a direction control method used in a radio base station that communicates with a plurality of mobile stations by using an adaptive array device in a radial division multiple access method, and includes a response vector calculation step based on calculating a response vector representing a relative direction of each mobile station from signals received from the plurality of mobile stations; a determination step of determining, as a target, one mobile station whose direction is unknown from the wireless base station among the plurality of mobile stations a mobile station; a first operation step of calculating parameters for forming, with respect to the target mobile station, a direction diagram in which only a direction indicated by a response vector calculated for other mobile stations other than the target mobile station is used as a zero point; A first control step of forming a transmission pattern for the target mobile station according to the calculated parameters; a second control step of outputting transmissions to other mobile stations simultaneously with the start of transmission to the target mobile station Change to the specified value.

In addition, the program of the present invention is a computer-executable program for performing direction control with a computer in a wireless base station that communicates with a plurality of mobile stations by using an adaptive array device in a radial division multiple access method, which causes the computer to execute : a response vector calculation step, which calculates a response vector representing a relative direction of each mobile station from signals received from the plurality of mobile stations; a determination step, which calculates a direction from the wireless base station among the plurality of mobile stations An unknown mobile station is determined as a target mobile station; a first calculation step, which calculates parameters for forming a direction diagram with the direction indicated by the response vector calculated for other mobile stations as a zero point for the target mobile station; A control step of forming a transmission pattern for the target mobile station according to the calculated parameters; a second control step of changing transmission outputs to other mobile stations simultaneously with the start of transmission to the target mobile station for the specified value.

Since the radio base station performing direction control according to this method or procedure transmits a signal to said target mobile station by means of a forced zero pattern with a zero point set in the direction of other mobile stations and to other mobile stations by means of a power-off pattern with reduced transmission gain Therefore, it is possible to ensure an appropriate strength ratio between the desired signal and the undesired signal in the direction of each mobile station, and to maintain a suitable communication quality with an unknown target mobile station for path division multiplexing communication. .

Description of drawings

FIG. 1 is a block diagram showing the configuration of a radio base station 100 .

FIG. 2 is a block diagram showing the configuration of the adaptive array unit 10 .

FIG. 3 is a schematic diagram showing a directivity pattern formed for two mobile stations of path division multiplexing based on forced zero weighting and power-off weighting.

FIG. 4 is a schematic diagram showing a pattern formed for three mobile stations of path division multiplexing based on forced zero weighting and power-off weighting.

FIG. 5 is a schematic diagram showing a pattern formed by conventional control.

Detailed ways

The wireless base station of this embodiment uses both the Time Division Multiple Access/Time Division Duplex (TDMA/TDD: Time Division Multiple Access/Time Division Duplex) method and the Path Division Multiple Access (PDMA: Path Division Multiple Access) method specified in the PHS standard. A wireless base station that multiplexes multiple signals and transmits and receives the signals using one carrier. The radio base station transmits or receives simultaneously by path-division multiplexing a maximum of four signals per time-division unit time in the time-division multiple access method.

<overall structure>

FIG. 1 is a block diagram showing the configuration of a radio base station 100 according to this embodiment. The radio base station 100 is composed of an adaptive array unit 10 , a modem unit 40 , a baseband unit 50 , and a control unit 60 .

The baseband unit 50 inputs a plurality of voice or data baseband signals from a plurality of lines connected through the telephone switching network outside the figure, and forms the signals into a time-division multiplexed signal, and then outputs the time-division multiplexed signal to the modem Tuning section 40. In addition, it decomposes the time-division multiplexed signal input from the modem unit 40 into individual signals, and outputs the signals to the line.

The baseband unit 50 performs this time-division multiplexing process in accordance with the TDMA/TDD method stipulated in the PHS standard. The time-division multiplexing signal in this standard is composed of repeated TDMA/TDD frames with a period of 5 mS, and one TDMA/TDD frame consists of 4 transmission time slots and 4 reception time slots that divide each period into 8 equal parts. One time slot each for transmission and reception constitutes a bidirectional communication channel according to time division multiple access/time division duplex. Thus, this one time-division multiplexed signal constitutes four communication channels.

The baseband unit 50 executes in parallel the process of time-division multiplexing a maximum of 4 lines of signals of a maximum of 4 time-division multiplexed signals that are path-division multiplexed.

Modulation and demodulation section 40 uses π/4 phase-shift QPSK (Quadrature Phase ShiftKeying) modulation mode to output to adaptive array section 10 after the time division multiplexing signal input from baseband section 50 is modulated, and transfers from adaptive array section The signal input from 10 is demodulated into a time-division multiplexed signal and output to the baseband unit 50 . The modulation/demodulation unit 40 executes the modulation/demodulation processing in parallel on up to four time-division multiplexed signals that are path-division multiplexed.

The adaptive array unit 10 uses each time slot in each TDMA/TDD frame (hereinafter simply referred to as a time slot) to use each mobile station connected to the time slot by path division multiplexing as a desired mobile station, and assigns The mobile station forms the appropriate pattern. At this time, the adaptive array unit 10 performs control according to an instruction from the control unit 60 according to one of the following methods: (1) forming a normal pattern; (3) forming a direction diagram for other mobile stations simultaneously path-division multiplexed with the mobile station and adjusting the transmission output.

The adaptive array unit 10 separates the signal of each mobile station from the received signal of the path division multiplex using each pattern thus formed, outputs the signal to the modem unit 40, and transmits the signal input from the modem unit 40 to The signal of each mobile station is sent only in the direction of each mobile station.

The control unit 60 is specifically realized by a CPU (Central Processing Unit) and a memory, etc., and controls the entire wireless base station by executing a program in the memory by the CPU.

In particular, the control unit 60 includes a mobile station specifying unit 61 and a transmission output instructing unit 62 for instructing all the mobile stations of the adaptive array unit 10 when there is no mobile station with an unknown direction from the radio base station in the path division multiplexed mobile stations. The direction control units 31 to 34 calculate weights by the method of (1) above. When a mobile station whose direction is unknown is determined by the mobile station determining section 61, it indicates that the direction control section using the mobile station as the required mobile station uses the method of (2) and indicates that the mobile station will be multiplexed simultaneously with the mobile station. The direction control unit of the other mobile station used as the desired mobile station forms a direction pattern by the method of (3) above. For the direction control section of the instruction method (3), the transmission output instruction section 62 instructs the transmission output level.

<Adaptive Array Division>

FIG. 2 is a block diagram showing the structure of the adaptive array unit 10 . The adaptive array unit 10 is composed of antennas 11 to 14 , a wireless unit 20 and a signal processing unit 30 .

The wireless unit 20 is composed of receiving units 211 to 214 , transmitting units 221 to 224 provided for each antenna, and transmission/reception selector switches 231 to 234 . Each receiving unit 211 to 214 includes a low-noise amplifier or the like, which converts a high-frequency signal received by each antenna into a low-frequency signal, amplifies it, and outputs it to the signal processing unit 30 . Each of the transmitting units 221 to 224 includes a high-power amplifier, etc., which convert the low-frequency signal input from the signal processing unit 30 into a high-frequency signal, amplify it to a transmission output level, and output it to each antenna.

The signal processing unit 30 is composed of direction control units 31 to 34 installed in mobile stations that are multiplexed by each path, and adders 361 to 364 that are installed in each antenna. Specifically, a programmable DSP (Digital Signal Processor) is used to realize accomplish.

Each direction control unit 31-34 is provided correspondingly to each mobile station of the path division multiplexing, and according to the formation method of the direction diagram instructed by the control unit 60, each time slot is divided into each path division multiplex on the time slot. The multiplexed mobile station forms an appropriate pattern for each desired mobile station by changing the amplitude and phase of the transmission/reception signal for each antenna.

The adders 361 to 364 add the transmission signals whose amplitudes and phases have been changed by the direction control units 31 to 34 for each antenna, and output the signals to the wireless unit 20 .

<Direction Control Unit>

The direction control unit 31 is composed of a received signal adjustment unit 310, a weight calculation unit 330, a reference signal generation unit 340, and a transmission signal adjustment unit 350, and itself forms an appropriate direction pattern for a mobile station as a desired mobile station.

In addition, since the other direction control units 32 to 34 also have the same configuration, the direction control unit 31 will be described as a representative.

The received signal adjustment unit 310 includes multipliers 311 to 314 and an adder 320 , and the multipliers 311 to 314 for weighting calculated by the weighting calculation unit 330 change the amplitude and phase of the received signal of each antenna input from the wireless unit 20 . And add them with adder 320 .

The reference signal generator 340 generates a reference signal for a desired mobile station from a signal of a fixed predetermined value, such as a preamble and a unique word which are codes for symbol synchronization in the PHS standard. In addition, the reference signal generator 340 modifies the signal modulated by a known modulation method, for example, a signal subjected to π/4 phase-shift QPSK modulation, by correcting the symbol point of the information obtained after demodulation to that obtained in the modulation method The position is then remodulated to generate a reference signal for the desired mobile station.

The weight calculation unit 330 calculates a weight for each reception slot according to the pattern formation method instructed by the control unit 60 .

The transmission signal adjustment unit 350 is provided with multipliers 351 to 354, and the multipliers 351 to 354 for weighting calculated at the end of the immediately preceding reception slot in the transmission slot constituting a communication channel paired with the reception slot. The amplitude and phase of the transmission signal input from the modem unit 40 are changed for each antenna.

<Weight Calculation Department>

The weight calculation unit 330 includes a response vector calculation unit 331, an RSSI calculation unit 332, a normal weight calculation unit 333, a forced zero weight calculation unit 334, a power failure weight calculation unit 335, and a weight selection unit 336. The calculated response vectors of the desired mobile stations and the response vectors of the unwanted mobile stations provided by the direction control sections 32 to 34 are weighted.

The response vector calculation unit 331 calculates a response vector of a desired mobile station from the reception signal of each antenna input from the radio unit 20 and the reference signal generated by the reference signal generation unit 340 for each slot. The response vector calculation unit 331 outputs the calculated response vector to the weight calculation unit 330 , and outputs it to the direction control units 32 to 34 and the control unit 60 at the same time.

The RSSI calculation unit 332 calculates for each time slot the strength of the signal component of the desired mobile station in the signal received by the wireless unit 20 at the time slot, and outputs it to the control unit 60 .

When the normal weight calculation unit 333 is instructed by the control unit 60 to form a pattern according to the method (1), it sequentially calculates the reference signal generated by the reference signal generation unit 340 and the received signal adjustment unit according to the MMSE method. The average of the squares of the differences of the received signals synthesized at 320 is the minimum weighted optimal value. Usually, the weight calculation unit 333 obtains the optimal weight value by solving the Wiener solution, which is the condition for providing the optimal weight value in the MMSE method, using sequential calculation algorithms such as the LMS algorithm and the RLS algorithm.

The Wiener solution and the sequential calculation algorithm for obtaining the Wiener solution are described in detail in the "Adaptive Signal Processing of Array Antenna", and the detailed description thereof is omitted here.

The forced zero weight calculation unit 334 calculates the direction indicated by the response vector of the unwanted mobile station provided by the direction control units 32 to 34 when the control unit 60 instructs to form a direction map according to the method (2) above. Weighted for zero alignment.

When the power failure weight calculation unit 335 is instructed by the control unit 60 to form a directional pattern according to the method (3), it calculates the direction of the radiation in the direction indicated by the response vector of the desired mobile station calculated by the response vector calculation unit 331. Beam alignment, weighting of zero alignment in directions indicated by response vectors supplied from direction control sections 32 to 34 with respect to unwanted mobile stations other than direction-unknown mobile stations. When the direction-unknown mobile station is the only unwanted mobile station, and therefore the response vector of the unwanted mobile station is not provided, the power-off weight calculation unit 335 calculates weights for forming a pattern equal to each direction.

In order to reduce interference from mobile stations with unknown directions, the power failure weight calculation unit 335 further changes the calculated weights so as to form a pattern in which the gain is attenuated by the same predetermined value in each direction, for example, 15 dB. However, when the transmission output is instructed by the transmission output instruction unit 62, the weighting is changed according to the instruction.

The weight selection unit 336 selects the weight calculated by one of the normal weight calculation unit 333, the forced zero weight calculation unit 334, and the power-off weight calculation unit 335 corresponding to the formation method of the pattern instructed by the control unit 60, and outputs it to the received signal The adjustment unit 310 and the transmission signal adjustment unit 350 .

<Details of Compulsory Zero Weighting Calculation Department>

Specifically, taking an adaptive array device having four antennas as an example, the forced zero weight calculation unit 334 calculates the weight for zero alignment in the direction indicated by the response vector of the unwanted mobile station as follows.

That is, express the response vector of the unwanted mobile station as

H=[h ₁ , h ₂ , h ₃ , h ₄ ] ^T ( ^T is transpose)

Express weighting as

W=[w ₁ , w ₂ , w ₃ , w ₄ ] ^T

, let the relationship between the response vector and the weighting

w ₁ ^* h ₁ +w ₂ ^* h ₂ +w ₃ ^* h ₃ +w ₄ ^* h ₄ ＝0( ^* is complex conjugate)

The established weights form a pattern that is zero-aligned in the direction indicated by the response vector of the unwanted mobile. The forced zero weight calculation unit 334 solves this relational expression simultaneously with respect to the response vectors of a plurality of unwanted mobile stations, and calculates weights for zero alignment of all the unwanted mobile stations.

<Details of Power Outage Weighted Calculation Unit>

In terms of obtaining the weighted optimal value by solving the Wiener solution of the MMSE method using sequential calculation algorithms such as the LMS algorithm and the RLS algorithm, the power failure weight calculation unit 335 is the same as the normal weight calculation unit 333, but it calculates in advance The weights for forming the same pattern for each direction are memorized, and are used when the mobile station whose direction is unknown is the only unwanted mobile station.

Furthermore, the power failure weight calculation unit 335 multiplies the calculated weight by a predetermined constant and outputs it so that the gain of the pattern is attenuated by a predetermined value in each direction. When the transmission output level is instructed by the transmission output instruction unit 62, the multiplication constant is changed according to the instruction.

<Details of Mobile Station Identification Section>

The mobile station specifying unit 61 records the time when a signal was last received from each mobile station, compares the recorded time with the current time, and judges that the direction of the mobile station is unknown when no received signal from the mobile station is obtained for a certain period of time. Also, when the mobile station intends to start the path division multiplexing communication and has not received a signal from the mobile station even once, it is judged that the direction of the mobile station is unknown.

When there is no mobile station determined to have an unknown direction, the mobile station identification unit 61 instructs all the direction control units 31 to 34 of the adaptive array unit 10 to calculate weights by the normal weight calculation unit.

When there is a mobile station that is judged to have an unknown direction, it instructs the direction control section that handles the judged mobile station as a desired mobile station to calculate the weight by the forced zero weight calculation section, and at the same time indicates that it will be multiplexed with the mobile station at the same time The direction control unit of other mobile stations as desired mobile stations calculates weights by the power-off weight calculation unit, and instructs the transmission output level by the transmission output instruction unit 62 .

FIG. 3 is a schematic diagram showing a direction pattern formed by an adaptive array unit according to an instruction by the mobile station determination unit 61 when two mobile stations are path division multiplexed and it is judged that the direction of one of them is unknown.

In the figure, 500 is a wireless base station, 501 is a direction-aware mobile station, 511 is a direction map formed according to the power-off weighting for the mobile station 501, 502 is a direction-unknown mobile station, and 512 is a direction diagram based on the mandatory power-off weight for the mobile station 502. Orientation map formed with zero weighting.

As shown in the figure, the effects of forced zero and power outage combine to make pattern 511 dominant in the direction of mobile station 501 and pattern 512 in directions other than it.

This pattern is formed based on the weights calculated on the reception slot, but the mobile station specifying unit 61 instructs each direction control unit to use the immediately preceding reception slot on the transmission slot that forms a communication channel paired with the reception slot. The weighting calculated at the end of the time slot is used to transmit the signal with the same pattern as at the end of the receive time slot.

By transmitting and receiving signals using this pattern, path division multiplexing communication can be performed even if the direction of the mobile station 502 is unknown.

Fig. 4 is a schematic diagram showing a pattern formed when three mobile stations are path division multiplexed.

In the figure, 400 is a wireless base station, 401 and 402 are direction-aware mobile stations, 411 and 412 are direction diagrams respectively formed according to power-off weights for mobile stations 401 and 402, 403 is a direction-unknown mobile station, and 413 is The pattern formed according to the forced zero weighting for the mobile station 403 .

As shown in the figure, the effects of forced zero and power off complement each other to make pattern 411, pattern 412, and pattern 413 dominant for the direction of mobile station 401, the direction of mobile station 402, and directions other than mobile stations 401 and 402, respectively.

This pattern is formed based on the weights calculated on the reception slot, but the mobile station specifying unit 61 instructs each direction control unit to use the immediately preceding reception slot on the transmission slot that forms a communication channel paired with the reception slot. The weighting calculated at the end of the time slot is used to transmit the signal with the same pattern as at the end of the receive time slot.

By transmitting and receiving signals using this pattern, path division multiplexing communication can be performed even if the direction of the mobile station 403 is unknown.

<Details of the sending output instruction section>

With regard to a mobile station communicating by means of a pattern formed based on the power-off weight, when the error rate of a received signal from the mobile station increases, the transmission output instructing section 62 instructs the power-off weight calculation section to reduce the attenuation amount of the pattern, when When the error rate of the received signal from the mobile station decreases, the power failure weight calculation unit is instructed to increase the attenuation amount of the pattern.

According to this configuration, since the amount of attenuation of the pattern for the mobile station whose error rate increases is reduced and the transmission signal strength is increased, an effect of reducing the error rate can be expected.

<Summary>

As described above, when one of the mobile stations performing path division multiplexing communication is direction-unknown, the wireless base station 100 calculates the forced zero weighting for the mobile station without using the response vector of the mobile station, and calculates the zero weighting for the other mobile stations. The outage weights are calculated and communication takes place by means of the pattern formed from the respectively calculated weights. According to this, it is possible to ensure an appropriate strength ratio between the desired signal and the undesired signal in the direction of each mobile station, and it is possible to perform effective path division multiplexing communication with a mobile station whose direction is unknown.

<supplement>

As above, the radio base station according to the present invention has been described through the embodiment, but the present invention is of course not limited to the embodiment. Right now,

(1) The mobile station specifying unit 61 judges that the direction of the mobile station is unknown when (a) the received signal from the mobile station is not obtained for a certain period of time. In addition, (b) the error rate of the received signal is greater than a predetermined value, ( c) The strength of the received signal is lower than a threshold value, and (d) the fading speed is higher than a predetermined value, and it is judged that the direction of the mobile station is unknown.

According to this configuration, since the judgment condition that the formation accuracy of the pattern is not good is included in addition to the case where a received signal is not obtained for a certain period of time, it is possible to more accurately judge the state in which the above-described directional control should be performed.

(2) Regarding the attenuation amount of the pattern formed by the power-off weighting, the transmission output instructing section 62 (a) decreases the attenuation when the error rate of the received signal increases when receiving a signal from a mobile station communicating with the pattern amount, increase the attenuation amount when the error rate decreases; it can also be (b) reduce the attenuation amount when the signal strength received from the mobile station decreases, and increase the attenuation amount when the signal strength increases; (c) when Decrease the attenuation amount when the fading speed of the mobile station increases, and increase the attenuation amount when the speed decreases; (d) reduce the attenuation amount when the modulation speed of the received signal from the mobile station increases, and increase the attenuation amount when the speed decreases. A large amount of attenuation; (e) obtaining from the mobile station a reception error rate discriminated when the mobile station receives, reducing the attenuation amount when the reception error rate increases, and increasing the attenuation amount when the error rate decreases.

According to this structure, since the attenuation amount is adjusted including the determination condition that the communication quality is deteriorated due to the attenuation of the pattern by the mobile station communicating with the pattern formed by the power-off weight, it can be expected to improve the communication quality with the power-off mobile station. .

(3) In addition, the present invention may be a method including the steps described in the embodiments. In addition, it may be a computer program for realizing such a method with a computer system, or may be a digital signal representing the program.

In addition, the present invention may also be a computer-readable recording medium on which the program or the digital signal is recorded, such as a floppy disk, hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, semiconductor memory, etc. .

In addition, the present invention may also be the computer program or the digital signal transmitted via an electric communication line, a wireless or wired communication line, or a network such as the Internet.

In addition, the present invention may be a computer system including a microprocessor and a memory storing the program, and the microprocessor implements the method by executing the program stored in the memory.

In addition, the program or the digital signal may be recorded on the recording medium for transmission, or may be transmitted via the network or the like and executed in another independent computer system.

Industrial availability

The radio base station according to the present invention is suitable for a radio base station which communicates with a plurality of mobile stations by using an adaptive array device in a radial division multiple access method. Path division multiplexing communication can be started even when it is unknown, which helps to ease the limitation of communication sequence and improve the quality of wireless communication.

Claims (4)

1. wireless base station, it is by using adaptive array apparatus with directly dividing multi-access mode and a plurality of mobile radio station to communicate, and it is characterized in that: described wireless base station possesses

The response vector computing unit, it calculates the response vector of the relative direction of each mobile radio station of expression according to the signal that receives from described a plurality of mobile radio stations;

Determining unit, it is determined in described a plurality of mobile radio station from a not clear target mobile radio station of the direction of wireless base station;

The 1st arithmetic element, its calculate in order to form at described target mobile radio station will be only to the parameter of the represented direction of the response vector that other mobile radio stations calculated except that described target mobile radio station as the directional diagram at zero point;

The 1st control unit, it is according to the sending direction figure of the described parameter formation of calculating at described target mobile radio station;

The 2nd control unit, it will change to setting to the transmission output of other mobile radio stations when the transmission of described target mobile radio station is begun.

In the claim 1 record the wireless base station, it is characterized in that: described wireless base station also possesses

Determination unit, it measures the signal strength signal intensity that receives from mobile radio station,

The error rate that described determining unit does not obtain (a) more than during certain received signal, (b) received signal greater than the intensity of setting, (c) received signal less than threshold value or (d) rapidity of fading mobile radio station that is higher than setting be defined as described target mobile radio station.

In the claim 2 record the wireless base station, it is characterized in that:

Error rate, intensity and the modulating speed of the also corresponding signal that is received from the controlling object mobile radio station of described the 2nd control unit, the rapidity of fading of controlling object mobile radio station and control one of reception error rate of this mobile radio station that the object mobile radio station notified certainly will send to export and be increased and decreased from described setting.

4. direction-controlling method, it is characterized in that: comprise by using adaptive array apparatus to use in the wireless base station that directly divides multi-access mode and a plurality of mobile radio station to communicate

The response vector calculation procedure, it calculates the response vector of the relative direction of each mobile radio station of expression according to the signal that receives from described a plurality of mobile radio stations;

Determining step, it will be defined as the target mobile radio station from a not clear mobile radio station of the direction of described wireless base station in described a plurality of mobile radio stations;

The 1st calculation step, its calculate in order to form at described target mobile radio station will be only to the parameter of the represented direction of the response vector that other mobile radio stations calculated except that described target mobile radio station as the directional diagram at zero point;

The 1st controlled step, it is according to the sending direction figure of the described parameter formation of calculating at described target mobile radio station;

The 2nd controlled step, it will change to setting to the transmission output of other mobile radio stations when the transmission of described target mobile radio station is begun.

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