JP2003115792A - Adaptive array base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adaptive array base station in which the voice quality of other base station connecting terminal and its own base station connecting terminal can be guaranteed. SOLUTION: An adaptive array base station 202 receiving a synch burst at the third slot of 1 frame from a terminal (S701) transmits a synch burst beam to the terminal in the direction receiving the sync burst at the sixth slot of 1 frame (S703). Subsequently, the adaptive array base station 202 receives a TCH burst at the third slot of 2 frame from the terminal (S705). The adaptive array base station 202 transmits a synch burst NULL to the terminal in the direction receiving the TCH burst at the sixth slot of 2 frame (S707).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to SDMA (Space Div)
The present invention relates to a communication system of the ision multiple access (space division multiple access) system, and to an adaptive array base station adopting the SDMA system.

[0002]

2. Description of the Related Art In an adaptive array base station, when a terminal connected to its own base station (terminal connected to its own base station) attempts a handover, there is a possibility that the terminal fails to be returned to the own base station. Therefore, the base station side enters the transmission / reception mode of the synchronous burst for up to 15 seconds. Then, even if a burst other than the synchronous burst is received during the synchronous burst transmission / reception mode, it is simply discarded (prior art 1). Also, when interference from a terminal connected to another base station becomes large due to movement or the like, the scramble seed (8
If the bit identification information) is the same, it becomes impossible to distinguish between the desired wave from the base station connection terminal and the interfering wave from another base station connection terminal. ) Was formed and could be locked by the transmission weight, it becomes impossible to lock (prior art 2).

[0003]

However, by simply discarding another burst without using the spatial multiplexing technique as in the prior art 1, a terminal (for example, terminal A) that is connected to another base station. When the TCH burst of the communication channel is received from, null is not formed in that direction, which causes interference to the terminal A. In addition, when the transmission weight cannot be locked as in the case of the conventional technique 2, time division multiplexing is impaired, which causes interference with a terminal connected to another base station. The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an adaptive array base station capable of guaranteeing the communication quality of another base station connecting terminal and its own base station connecting terminal.

[0004]

In order to solve the above problems, the adaptive array base station of the first invention of the present application is
In the synchronous burst transmission / reception mode for establishing synchronization with the mobile communication terminal, when the burst of the speech channel is received at the timing of the synchronous burst reception, the timing of the synchronous burst transmission is transmitted in the direction in which the burst of the speech channel is sent. And a means for executing adaptive null steering.

Further, the adaptive array base station of the second invention of the present application is for establishing frame synchronization on a burst received at the timing of receiving the synchronous burst in the synchronous burst transmission / reception mode for establishing synchronization with the mobile communication terminal. A first code sequence that refers to the signal and compares the code sequence of the frame synchronization establishment signal with a first code sequence that is held in advance
If the number of mismatch bits is less than a predetermined number as a result of comparison by the first comparison means and the first comparison means, the received burst is recognized as a synchronization burst, and the synchronization burst is transmitted in the direction in which the synchronization burst is sent. As a result of the comparison by the means for executing adaptive beam transmission at the transmission timing and the first comparing means, if the number of non-matching bits is a predetermined number or more,
As a result of comparison by the second comparing means for comparing the code string of the frame synchronization establishment signal with the second code string held in advance and the second comparing means, the number of mismatch bits is less than a predetermined number. In the case of, the received burst is recognized as a burst of the communication channel, and means for executing adaptive null steering at the timing of the synchronous burst transmission is provided in the direction in which the burst of the communication channel is sent. Characterize.

Further, the base station of the third invention of the present application performs means for performing communication in a space-time division multiple access system with respect to a mobile communication terminal to be transmitted and buffers transmission weight information, and a transmission weight. When an unlock occurs, a means for selecting the optimum transmission weight information based on predetermined conditions from the buffered transmission weight information, and determining the transmission weight based on the optimum transmission weight information Means, and means for transmitting to the mobile communication terminal to be transmitted using the determined transmission weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the adaptive array base station according to the present invention applied to a PHS base station which is an adaptive array base station for digital wireless communication will now be described in detail with reference to the accompanying drawings. explain. The term "PHS base station" used herein means a base station used in a personal handy phone system (ARIB STD-28).

The accompanying drawings are FIGS. 1 to 13, FIG. 1 is a sequence chart at the time of handover, FIG. 2 is a diagram showing beam transmission and NULL transmission at an adaptive array base station, and FIG. 3 is synchronization burst transmission after handover. Fig. 4
Is a functional block diagram of an adaptive array base station which is an embodiment of the present invention, FIG. 5 is a TCH data format,
6 is a data format of SYNC, FIG. 7 is a time slot example of synchronous burst beam transmission and synchronous burst NULL transmission, FIG. 8 is a diagram showing synchronous burst NULL transmission after handover, and FIG. 9 is a transmission wait lock of an adaptive array base station. FIG. 10 is a diagram showing a state, FIG. 10 is a diagram showing transitions of a desired wave and an interfering wave, FIG. 11 is a diagram showing a transmission wait unlock state of an adaptive array base station, and FIG. 12 is a time for explaining a transmission weight information buffering method. An example of slots, FIG. 13 is a diagram showing a state in which buffered transmission weight information is used.

<First Embodiment> The channels provided in the radio section basically consist of a call channel (TCH) for transferring user information and a control channel (CCH) for transferring control signals. And from CCH to TC
When shifting to H or when the terminal is handed over, synchronization burst is used to establish synchronization between the base station and the terminal, and then a call is made on the TCH. In the case of the personal handyphone system, the sync burst format has 32 bits of upstream sync words UW, and the TCH format has 16 bits of uplink UW.

In the PHS base station, when a terminal connected to the own base station attempts a handover, the terminal may fail to be handed over and may be switched back to the own base station. Enters the synchronous burst transmission / reception mode of the synchronous burst for up to 15 seconds. Then, even if a burst other than the synchronization burst is received during the mode, the burst is simply discarded and no change is made to the transmission of the next synchronization burst.

FIG. 1 is a conventional sequence chart when a handover is successful. There are two types of handover, one is an instruction from the base station to switch, and the other is an instruction from the terminal to switch. The former sequence chart is shown here. As shown in the figure, after the handover instruction 105 is issued from the handover source base station 103a, the terminal 101 and the handover destination base station 103 are issued.
b and the call setup process (handover process 10 of FIG.
9) is performed, but in the meantime, in the handover source base station 103a, since there is a possibility that the terminal 101 may fail the handover and come back, the synchronization burst (107a-
107d) is being transmitted. If the handover is successful, the handover source base station 103a performs a disconnection process after transmitting a synchronization burst for 15 seconds. 2 and 3 are diagrams showing a state when processing is performed according to the conventional sequence chart.

FIG. 2 shows a conventional example in which a terminal PS2 (hereinafter, PS2) is connected to a PHS base station 202 (hereinafter, base station 202) and a terminal PS1 (hereinafter, PS2) is connected to the base station 201.
FIG. 1 is a diagram showing a state when 1) is connected. The base station 202 transmits an adaptive beam to the PS2 connected to its own base station (adaptive beam forming), and gives interference to PS1 connected to the base station 201 (other base station). Not null
Form (adaptive null steering). Also, the base station 202 in a call state with PS2 receives a burst signal (hereinafter, TCH burst) from PS2 in the TCH reception mode and transmits an adaptive beam in that direction. Further, when the base station 202 receives the TCH burst from the PS1 that is in communication with the base station 201, the base station 202 regards the burst as an interference wave and forms NULL in that direction.

FIG. 3 is a diagram showing a state in which the PS2 connected to the base station 202 in the conventional example is handed over to another base station. In the base station 202, since PS2 may fail to hand over and come back, the synchronous burst transmission / reception mode is entered for a maximum of 15 seconds. At this time, when the base station 202 receives the TCH burst from the PS1, the base station 202 is in the synchronous burst transmission / reception mode, so that the TCH burst is simply discarded and the transmission of the next synchronous burst is not affected. . Therefore, PS1
The sync burst is transmitted without forming a null in the direction of, and it becomes an interference wave for PS1.

According to the first embodiment of the present invention, when a TCH burst is received during a synchronous burst transmission / reception mode in a handover source base station after a terminal is handed over, it is regarded as an interference wave and a TCH burst is received. The synchronization burst is transmitted so that a NULL is formed in the direction in which is transmitted. By this means, it is possible to avoid an interfering wave in the synchronization burst with respect to a terminal unrelated to handover.

Referring to FIG. 4, there is shown a functional block diagram showing an embodiment in which the adaptive array base station according to the present invention is applied to a PHS base station which is an adaptive array base station for digital radio communication. . In FIG. 4, adaptive array base station 20 according to the present embodiment is shown.
2 includes four antennas ANT1 to ANT4, and these antennas ANT are connected to the transmission / reception changeover switch 12. The transmission / reception change-over switch 12 controls these antennas ANT1 to ANT4 in a time division manner to perform switching control between transmission and reception. A reception system module 14 and a transmission system module 22 are connected to the transmission / reception changeover switch 12.

The receiving system module 14 includes each antenna AN.
Four low noise amplifiers (LNA) 1 for each T
6, a down converter (D / C) 18, and an A / D converter (A / D) 20. The reception system module 14 is also connected to the modem unit 30, and the low noise amplifier 16, the down converter 18, and the A / D converter (A / D) 20 are connected to the modem unit 30 from the transmission / reception changeover switch 12 which is a signal path. Connected in order.

Similarly, the transmission system module 22 includes four D / A converters (D / A converters) provided for each antenna ANT.
A) 24, upper converter (U / C) 26, and multiplication circuits (MP) 28a and b. The transmission system module 22 is also connected to the modem section 30, and the D / A
The converter 24, the upper converter 26, and the multiplication circuits 28a and 28b are connected in this order from the modem unit 30 which is a signal path toward the transmission / reception system changeover switch 12. In the case of spatially multiplexing two calls, the multiplication circuits 28a and 28b are used so that each call can be transmitted with a different weight.

The modem section 30 is composed of a plurality of CPUs, and performs modulation / demodulation of transmission / reception data and phase control by digital signal processing. Specifically, the following 5
Do one control. 1. The digital signals converted at the final stage of the reception system module 14 are combined and demodulated so that, for example, D / U (Desire / Undesire: desired wave / interference wave) is maximized. 2. The phase of reception at the antenna ANT is calculated, and control is performed so that the phase becomes equivalent at the antenna end during transmission. As a result, directivity can be imparted to both the transmitting and receiving terminals in the direction of the communication terminal. 3. It is suppressed by forming a null point in the arrival direction of the interference wave and the delayed wave. 4. By controlling the phases of the signals supplied to the n antennas, it becomes possible to direct the beam in an arbitrary direction and narrow the beam for transmission. 5. It reduces interference given to the surrounding base stations and terminals other than the user terminal in communication or exchanging data (communication) in the downlink direction.

The modem section 30 is connected to the control section 32. The control unit 32 includes a plurality of CPUs and controls the entire base station 202. Specifically, the following six controls are performed. 1. The modem unit 30 is instructed of necessary parameters and timing, and the data received by the modem unit 30 is processed. In addition, data to be radiated in the air is created and passed to the modem unit 30. Further, it instructs the control of the transmission output by the weighting calculated by the calibration. 2. The rate of change of the Spatial Signature (reception response vector) from the user terminal (user's terminal, hereinafter simply referred to as user) is calculated. 3. The statistical processing of the received signal level RSSI from the user is performed. 4. Spatial-multiplexed physical slot allocation is performed by a logic so that the GOS (Grade Of Service: speech quality) of the spatially-multiplexed call is as similar as possible to the GOS of a normal call that is not spatially multiplexed. 5. When a call is established by spatial multiplexing for multiple users, the C / I (Carrier / Interference) to each user should be greater than or equal to the value required to maintain good GOS for each user. Compute the weights to. 6. It is connected to the ISDN line and executes interface processing with it.

The power supply unit 34 is a power supply unit that receives a power supply of 100 V and supplies power to the adaptive array base station 202. A digital signal processing unit is formed by the modem unit 30 and the control unit 32. The base station 202 performs adaptive array transmission in which each antenna is transmitted with a predetermined weight based on reception information (amplitude and phase) received from N (N is a natural number of 2 or more) antennas. .

As described above, in this embodiment, after the terminal is handed over, the adaptive array base station 202
During the synchronous burst transmission / reception mode in, the processing of and can be performed. When a sync burst is received: A sync burst beam is transmitted in the direction in which the sync burst is received. When a TCH burst is received: It is regarded as an interference wave, and a synchronization burst is transmitted so that NULL is formed in the direction in which the TCH burst is sent.

FIG. 5 shows a TCH (TCH burst) signal format. Ramp time for transient response R (guaranteing rise time of each slot) is 4 bits, start symbol SS (indicating signal start) is 2 bits, preamble PR (for establishing bit synchronization) is 6 bits, channel type
The CI is composed of 4 bits, the SA (SACCH) is composed of 16 bits, the error detection code CRC is composed of 16 bits, and the information bit I on which voice is actually carried is composed of 160 bits. For TCH, the sync word UW is 16 bits.

FIG. 6 shows a signal format of SYNC (synchronization burst). Ramp time R for transient response (guaranteeing the rise time of each slot) is 4 bits, start symbol SS (indicating the start of the signal) is 2 bits, preamble PR (for establishing bit synchronization) is 62 bits, channel type CI Is 4 bits, the destination identification code (including the calling code of the partner station to be connected) is 42 bits, the calling identification code (including the calling code of the local station) is 28 bits, the idle bit is 34 bits, and the error detection code CRC is It consists of 16 bits. S
For YNC, the sync word UW is 32 bits.

The sync word UW in both TCH (FIG. 5) and SYNC (FIG. 6) is a signal that has a unique code sequence per burst and is typically used to establish frame sync. This code is searched for from other people's signals and noise, and a selective filter is applied to this code to create a synchronization state.
In this embodiment, in order to distinguish whether the received burst is a synchronization burst or a TCH burst, this synchronization word U
Use W. The processing at this time is shown in steps 1 to 4.

Step 1: The burst received during the synchronous burst transmission / reception mode is first checked by the UW error number only to see if it is a synchronous burst. Specifically, originally SYNC (Fig. 6)
The code string included in the UW signal of is compared with the code string of the received burst UW signal, and the number of mismatch bits (UW error number)
To count. Step 2: If the number of UW errors is within the allowable range (4 bits or less in Japan, 1 bit or less in other countries), the burst is processed as a synchronization burst. That is,
At the next transmission, adaptive beam transmission is performed in the direction in which the synchronization burst is sent. Step 3: If the number of UW errors exceeds the allowable range, it is determined that the burst is not a synchronization burst, and then it is confirmed whether or not it is a TCH burst only by the number of UW errors.
Specifically, the code string originally included in the UW signal of the TCH (FIG. 5) burst is compared with the code string of the received burst UW signal, and the number of mismatch bits (the number of UW errors) is counted. Step 4: If the number of UW errors is within the allowable range (4 bits or less in Japan, 1 bit or less in foreign countries), the burst is processed as a TCH burst. That is,
At the next transmission, adaptive null steering is performed by transmitting synchronous burst in the direction in which the TCH burst is sent.

7 and 8 use steps 1 to 4 to
It is a figure explaining the embodiment in the case of distinguishing a synchronous burst / TCH burst. FIG. 7 shows an example of time slots for synchronous burst beam transmission and synchronous burst NULL transmission by the adaptive array base station 202. In the figure, the base station 202 receives a synchronization burst from the terminal in the third slot of one frame (S701). The adaptive array base station 202 performs synchronous burst beam transmission to the terminal in the direction in which the synchronous burst is received in the seventh slot (S703) of one frame. Subsequently, the adaptive array base station 202 receives 3 frames of 2 frames from the terminal.
The TCH burst is received at the slot (S705). The adaptive array base station 202 performs synchronous burst NULL transmission to the terminal in the direction in which the TCH burst is received in the 7th slot (S707) of 2 frames.

FIG. 8 shows the PS connected to the base station 202.
2 shows a state when handing over to another base station. PS that was in communication with the base station 202
When PS 2 has handed over, PS 2 may switch back to the base station 202, and thus enters the synchronous burst transmission / reception mode for up to 15 seconds. At that time, when the base station 202 receives the TCH burst of PS1 which is in a call state with the base station 201, the next synchronization burst is transmitted by forming NULL in that direction. By this means, it is possible to avoid an interfering wave in the synchronization burst for PS1 from the base station 202.

<Second Embodiment> FIG. 9 shows a base station 20.
2 terminals that are connected to 2 (adaptive array base station)
(PS2, PS3, PS4), adaptive beams are transmitted to them, and NULL is formed so as not to interfere with the terminal PS1 connected to the base station 201. Is. 3 aircraft (PS2-PS
The base station 202, which is in communication with 4), receives TCH bursts from three units (PS2 to PS4) in the TCH reception mode and transmits an adaptive beam in that direction. Further, when the base station 202 receives the TCH burst from the PS1 that is in communication with the base station 201, it regards it as an interfering wave and forms NULL in that direction. A state in which the directions of the adaptive beam and the NULL are determined and the transmission weight is fixed is called “transmission weight is locked”.

At the base station 202, three units (PS2 to P
Since S4) is in a call state, PS1 cannot hand over to the base station 202. Therefore, the base station 202 tries to continue forming NULL for PS1. Normally, each base station is provided with a scramble seed (8-bit identification information) so that it can distinguish between its own connected terminal, and that terminal connects to its own station based on the scramble seed attached to the burst from the terminal. It distinguishes between terminals and terminals connected to other stations.

If the scrambling seeds of the base station 201 and base station 202 are different, PS1
Since the scrambling seed of the TCH burst of is different from that of its own, it can be recognized that PS1 is a terminal connected to another station. Therefore, considering PS1 as an interference wave,
A null can be formed in that direction. However, when the scramble seeds of the base station 201 and the base station 202 are the same, under the situation A as shown below, the TCH burst from PS1 which is originally the disturbing wave and the TCH burst from PS2 which is the desired wave. Sometimes it can be indistinguishable from.

Situation A: FIG. 10 shows transitions of a desired wave and an interfering wave in the base station 202. The vertical axis represents the reception level and the horizontal axis represents time. In the figure, the level of the interfering wave 1003 from PS1 rises and the level of the desired wave 1001 from PS2 falls with the passage of time. In such a case, the base station 202 cannot distinguish between the desired wave and the interfering wave. FIG. 11 shows the base station 2
There are 3 terminals connected to 02 (PS2, PS3, PS
4) Yes, and is a diagram showing a state in which interference from the terminal PS1 connected to the base station 201 has increased due to movement or the like. In the case of FIG. 11, the reception level of the signal from each terminal changes and the state shown in FIG. 10 is obtained.

As a result, the null could be formed in the direction of the terminal connected to the other base station and the transmission weight could be used for locking. However, the lock is no longer possible and the null cannot be formed. As a result, it causes interference to the terminal connected to the other base station. In addition, until then, the terminal connected to the own base station was transmitting at a sufficient level, but since the transmission weight could not be locked, a sufficient level could not be secured for that terminal. The state as shown in FIG. 11 is referred to as “transmission wait unlock”.

The unlocking of the transmission wait occurs when the following two conditions are met. Condition: The interference wave RSSI value is higher than the desired wave RSSI value by a certain amount or more. Condition: The number of CRC errors is more than a certain value. The transmission wait is unlocked when both of the following conditions are met. Condition: Desired wave RSSI value is interfering wave
The value is sufficiently higher than the RSSI value. Condition: When the number of CRC errors is less than a certain value, or when a call with an interfering wave is cut off.

The base station 202 according to the present invention buffers the information (amplitude, phase, UW error number, CRC error number, etc.) related to the transmission weight at a predetermined timing (for example, every 5 msec). Then, in both of the following periods, an optimum one is selected from the buffered information regarding the transmission weight (hereinafter, referred to as “transmission weight information”),
Determine the transmission weight. Period: Unlocking to unlocking the transmission wait. Period: unlocking of transmission weight to disconnection of a call that is an interfering wave.

The transmission weight information is selected by selecting the optimum transmission weight information from the buffered transmission weight information until immediately before, and calculating the transmission weight from the "amplitude and phase of the optimum transmission weight information". Shall be used to transmit to the terminal connected to the own station. An example of a method of selecting the optimum transmission weight information is shown below. Selection method: CRC error count is 1 bit or less. When there are multiple CRC error numbers of 1 bit or less, the data is buffered at the closest time before the unlock occurs before the unlock occurs. Selection method: U if all CRC errors are 2 bits or more
The one with the smallest total value of W error count and CRC error count.
If there are multiple items with the same total value, they are buffered at the closest time when the unlock occurred before the unlock occurred.

FIG. 12 shows an example of a time slot of the transmission weight information buffering method. The frame length in this embodiment is 5 msec, and the buffering timing is also 5 msec. In the present embodiment, the transmission weight information is buffered every eight slots such as the third slot, the eleventh slot, the nineteenth slot, etc. (S1201), but it is obvious that the present invention is not limited to this. . Here, Table 1 shows a simple example of the buffering method.

[0037]

[Table 1]

In the present embodiment, the buffering is performed for 100 msec, and the buffering is performed once every 5 msec, so that there is a total of 20 pieces of information. The transmission weight information to be buffered is amplitude, phase, CRC error, and UW error. In this example, the transmission wait is unlocked when the interfering wave RSSI value is higher than the desired wave RSSI value by 15 dB or more and the number of CRC errors at that time is 2 bits or more. When unlocking, the difference between the disturbing wave RSSI value and the desired wave RSSI value is less than 15 dB, and the number of CRC errors is 1.
When it is less than or equal to bit.

In the case of Table 1, the disturbing wave RSSI value exceeds 16 dB over the desired wave RSSI value in item 8, and the number of CRC errors at that time is 9
Since it is bit, the transmission wait is unlocked at this time (S1203 in FIG. 12). The base station 202 calculates the transmission weight using the phase and the amplitude at the time of item4 in the case of Table 1, which satisfies the above-mentioned predetermined condition among the 20 pieces of transmission weight information up to immediately before item8. Send (Figure 1
2 S1205).

Since the transmission wait unlocked state continues from item 9 to item 11, the transmission weight is calculated from the buffering data in the same manner as item 8.
In item12, the difference between the desired wave RSSI value and the disturbing wave RSSI value is 8 dB, and the number of CRC errors at that time is 1 bit, so the desired wave and the disturbing wave can be distinguished, and beam transmission and NULL transmission can be performed. Therefore, at this time, the transmission wait is unlocked and the transmission wait can be locked again.

FIG. 13 shows that when there are three terminals (PS2, PS3, PS4) connected to the base station 202 and an adaptive beam is transmitted to them, the terminal P
It is a figure showing the state where S1 (connection terminal of base station 201) was approaching. In the base station 202, even when PS1 forming a NULL approaches and the transmission weight is unlocked, the immediately previous transmission weight is locked by using the buffering data as in the example of Table 1. You can use the best transmit weight in.
As a result, the interference that the base station 202 gives to PS1 can be suppressed to a minimum, and the desired wave (adaptive beam) to PS2 to PS4 can be secured to a minimum, so that all four units (PS1 to PS4) can talk. Quality is improved.

As described above, according to the present invention, it is possible to minimize interference with a terminal being connected to another base station, and also to secure a minimum level for the terminal connected to the own base station. Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this and can be used in a communication system other than the personal handyphone system.

[0043]

According to the adaptive array base station of the present invention, it is possible to guarantee the communication quality of the other base station connecting terminal and the own base station connecting terminal.

[Brief description of drawings]

FIG. 1 is a sequence chart at the time of conventional handover.

FIG. 2 is a diagram showing beam transmission and NULL transmission in an adaptive array base station when processing is performed according to the sequence of FIG.

3 is a diagram showing synchronous burst transmission after handover when processing is performed according to the sequence of FIG. 1. FIG.

FIG. 4 is a functional block diagram of an adaptive array base station that is an embodiment of the present invention.

FIG. 5 is a data format of a telephone channel TCH that is an embodiment of the present invention.

FIG. 6 is a data format of a synchronization burst SYNC which is an embodiment of the present invention.

FIG. 7 is a time slot example of synchronous burst beam transmission and synchronous burst NULL transmission according to the embodiment of the present invention.

FIG. 8 is a diagram showing synchronization burst NULL transmission after handover according to the embodiment of the present invention.

FIG. 9 is a diagram showing a transmission wait lock state of the adaptive array base station according to the embodiment of the present invention.

FIG. 10 is a diagram showing transitions of a desired wave and an interfering wave according to the embodiment of the present invention.

FIG. 11 is a diagram showing a transmission wait unlock state of the adaptive array base station according to the embodiment of the present invention.

FIG. 12 is a time slot example for explaining a method of buffering transmission weight information according to the embodiment of the present invention.

FIG. 13 is a diagram showing a state in which buffered transmission weight information is used according to the embodiment of the present invention.

[Explanation of symbols]

PS1, PS2, PS3, PS4 terminals 201 base station 202 Adaptive array base station

Continued front page    F-term (reference) 5J021 GA02 GA06 HA10 JA10                 5K022 FF00                 5K047 AA11 BB01 CC01 HH01 HH12                       HH44 JJ02 JJ08 MM11 MM24                       MM62                 5K059 CC02 CC04 DD31                 5K067 AA03 CC04 CC24 EE02 EE10                       GG03 HH21

Claims (3)

[Claims] 1. Space division multiple access in which the same physical slot is shared by a plurality of calls by selectively using adaptive beamforming for a mobile communication terminal to be transmitted and adaptive null steering for an interfering mobile communication terminal. In an adaptive array base station that performs communication using the method, in a synchronous burst transmission / reception mode for establishing synchronization with a mobile communication terminal, at the timing of receiving the synchronous burst,
An adaptive array base station, comprising means for executing adaptive null steering at the timing of synchronous burst transmission in the direction in which the burst of the speech channel is sent, when the burst of the speech channel is received. 2. Space division multiple access in which the same physical slot is shared by a plurality of calls by selectively using adaptive beamforming for a mobile communication terminal to be transmitted and adaptive null steering for an interfering mobile communication terminal. In an adaptive array base station that performs communication using the method, in the synchronous burst transmission / reception mode for establishing synchronization with the mobile communication terminal, the frame synchronization establishment signal on the burst received at the timing of receiving the synchronous burst is referred to. ,
First comparing means for comparing the code string of the frame synchronization establishing signal with a first code string held in advance, and as a result of the comparison by the first comparing means, the number of mismatch bits is a predetermined number. If less than, recognize the burst as a synchronization burst, in the direction in which the synchronization burst is sent,
As a result of the comparison by the means for executing adaptive beam transmission at the timing of synchronous burst transmission and the first comparing means, if the number of mismatch bits is not less than a predetermined number, the code string of the frame synchronization establishment signal is held in advance. When the number of mismatch bits is less than a predetermined number as a result of comparison by the second comparing means for comparing the stored second code sequence with the second comparing means, the burst is regarded as a burst of a communication channel. An adaptive array base station, comprising means for recognizing and performing adaptive null steering at the timing of synchronous burst transmission in the direction in which the burst of the communication channel is transmitted. 3. A mobile communication terminal to be transmitted,
In a base station that performs communication in the time-space division multiple access method, a means for buffering the transmission weight information and, when unlocking of the transmission weight occurs, a predetermined condition is selected from among the buffered transmission weight information. Means for selecting the optimal transmission weight information based on the above, means for determining the transmission weight based on the optimal transmission weight information, and means for transmitting to the mobile communication terminal to be transmitted using the transmission weight. A base station characterized by being provided.