HK1087851B

HK1087851B - Transmission beam control method, adaptive antenna transmitter/receiver apparatus and radio base station

Info

Publication number: HK1087851B
Application number: HK06109882.6A
Authority: HK
Inventors: 水口博则
Original assignee: 日本电气株式会社
Priority date: 2003-03-12
Filing date: 2004-03-09
Publication date: 2009-09-04

Description

Transmission beam control method, adaptive antenna transmitting/receiving apparatus, and radio base station

Technical Field

The present invention relates to a transceiver apparatus suitable for use in a code division multiple access (hereinafter abbreviated CDMA) mobile communication system.

Background

In a CDMA mobile communication system, typically, a plurality of mobile stations perform radio communication using the same common frequency band, and wave interference (i.e., multi-user interference) caused by radio communication of other mobile stations is a main cause of limiting the subscriber capacity of the mobile communication system. In order to increase subscriber capacity, the adaptive antenna is effective for suppressing wave interference during reception and for avoiding transmission in an unnecessary direction during transmission, and therefore, the interference power applied to other mobile stations is reduced.

As an example of the related art of a transmitting and receiving device using an adaptive antenna technology (hereinafter referred to as an adaptive antenna transmitting and receiving device), a technology of controlling directivity using a plurality of antenna devices is described in non-patent document 1(NTT DoCoMo scientific publication, volume 8, No. 1, month 4 of 2000). Non-patent document 1 discloses: the antenna gain in the mobile station direction is increased by giving a weighting coefficient (reception antenna weight) to each reception signal received by the plurality of antenna devices during reception, and the transmission beam is directed to the mobile station as a transmission object by multiplying the weighting coefficient (transmission antenna weight) generated according to the reception antenna weight by the transmission data of each antenna device during transmission.

As a method of generating the receive antenna weights, a method for realizing control to minimize a mean square error between Pilot symbols after despreading and a signal after RAKE synthesis generated by referring to information data symbols that have been temporarily determined is described in non-patent document 2(s.tanaka, m.sawahashi, and f.adachi, "Pilot symbol-associated coherent adaptive diversity for DS-cdma radio reverse link," ice trans.fundamental, volume E80-a, page 2445-2454, month 12 1997). Further, non-patent document 3(Tanaka, Harada, Ihara, Sawahashi, Adachi, "exterior technology characteristics of adaptive antenna diversity reception W-CDMA," Shingaku Gihou, RCS99-127, pages 45-50, 10 months 1999) describes an example of using transmit antenna weights generated according to the above-described receive antenna weights in downlink transmission (transmission in the direction from a radio base station to a mobile station).

In a CDMA mobile communication system, transmission power control (hereinafter abbreviated TPC) is generally performed to ensure transmission quality while avoiding unnecessary interference to other mobile stations. Particularly, the TPC technique is indispensable in CDMA because assigning a common frequency to a plurality of mobile stations generates common frequency interference.

The relationship between TPC and transmission beams in downlink transmission is considered as an example below.

In downlink transmission, the directivity of a transmission beam is controlled by using a plurality of antenna devices provided in a radio base station and multiplying each transmission antenna weight by transmission data. The mobile station instructs the radio base station to decrease the transmission power if the reception quality exceeds a required value, and instructs the radio base station to increase the transmission power if the reception quality falls below the required value. The instruction for increasing or decreasing the transmission power from the mobile station to the radio base station (hereinafter referred to as an increase/decrease instruction) uses TPC bits, which are included in a frame transmitted from the mobile station to the radio base station in each specified period. The radio base station extracts TPC bits from a frame transmitted from the mobile station and increases or decreases the transmission power to the mobile station according to the instruction.

Referring to fig. 1, an adaptive antenna transceiving apparatus related to the related art is explained below. The adaptive antenna transceiving apparatus shown in fig. 1 is an example of configuration for performing TPC in the adaptive antenna transceiving apparatus described in fig. 1 of non-patent document 1.

As shown in fig. 1, the adaptive antenna transceiver device of the prior art has the following structure, including: a plurality of (N, where N is a positive integer) antenna devices 301_1 to 301_ N arranged in an array form; reception-side multipliers 302_1 to 302_ N for multiplying reception antenna weights by reception signals that have been received by the antenna devices 301_1 to 301_ N; an adder 303 for adding (synthesizing) a plurality of reception signals that have been multiplied by the reception antenna weights and supplying the result as reproduction data; a reception antenna weight generation circuit 304 for calculating an optimum reception antenna weight to be multiplied by the reception signal that has been received by each antenna device 301_1 to 301_ N, based on the reproduction data that has been supplied as the output of the adder 303, and supplying the result to each corresponding reception-side multiplier 302_1 to 302_ N; a TPC bit decoding circuit 307 for extracting TPC bits from the reproduced data and then decoding the TPC bits to provide an instruction to increase or decrease the transmission power; an antenna weight switching circuit 305 for generating a transmission antenna weight based on the reception antenna weight which has been generated by the reception antenna weight generating circuit 304, and further increasing or decreasing the transmission antenna weight based on an instruction to increase or decrease the transmission power which has been supplied as an output of the TPC bit decoding circuit 307; and transmission-side multipliers 306_1 to 306_ N for multiplying transmission antenna weights, which have been supplied as outputs of the antenna weight conversion circuit 305, by transmission data and supplying the products to the antenna devices 301_1 to 301_ N. The adaptive antenna transceiving apparatus shown in fig. 1 shows the structure of a baseband signal processor, which is mainly used to perform signal processing for baseband transmission/reception data. The adaptive antenna transceiving device comprises a radio signal transceiver (not shown) having an RF receiver for converting radio frequency signals received by the antenna device into baseband signals and an RF transmitter for converting baseband signals into radio frequency signals.

In this structure, the antenna weight switching circuit 305 generates a transmission antenna weight based on the weight coefficient (reception antenna weight) that has been generated at the reception antenna weight generating circuit 304 so as to transmit in the same direction as the direction at the time of reception. Further, the antenna weight switching circuit 305 controls the transmission power by adjusting each transmission antenna weight in accordance with the instruction of increasing or decreasing the transmission power, which has been decoded at the TPC bit decoding circuit 307.

Generally, reasons that can be considered for increasing the transmission power of a radio base station include: a case in which the reception quality of the mobile station deteriorates due to shielding when the radio base station and the mobile station are blocked by, for example, a building or the like, or a case in which the transmission power is increased to compensate for the deterioration of the reception quality of the desired wave mobile station due to the deviation of the peak direction of the transmission beam formed at the radio base station from the mobile station as the transmission object (hereinafter referred to as "desired wave mobile station").

When the peak direction of the transmission beam deviates from the desired wave mobile station, the reception quality of the desired wave mobile station achieves a desired value by the TPC processing, but when another mobile station is located in the peak direction of the transmission beam, unnecessary interference power will be applied to this mobile station, and therefore, the transmission power must be increased for each mobile station. The maximum transmit power of a radio base station is typically limited by the capability of a power transformer providing power to the antenna arrangement, and therefore an increase in transmit power to each mobile station reduces the subscriber capacity that the mobile communication system can accommodate.

An object of the present invention is to provide an adaptive antenna transceiving apparatus capable of reducing unnecessary interference power applied to other mobile stations when TPC is applied at the time of downlink transmission due to a deviation of a peak direction of a transmission beam from a mobile station as a transmission object, and thus capable of preventing a reduction in the subscriber capacity of a mobile communication system.

Disclosure of Invention

In the present invention for achieving the above object, a change of an increase/decrease transmission power command that has been decoded from TPC bits is monitored, and when the increase/decrease command is biased toward the command to increase transmission power within a prescribed time interval that has been determined in advance, the transmission antenna weight or transmission power of each antenna device is adjusted, changing the peak direction or main lobe width of a transmission beam. These processes are repeated until the bias to the instruction to increase the transmission power in the instruction to increase/decrease the transmission power is eliminated, or until the number of changes of the transmission beam reaches the maximum value that has been predetermined.

When the peak direction of the transmission beam has been changed, the peak direction of the transmission beam may be corrected to the direction of the mobile station as the transmission subject. Alternatively, when the main lobe width of the transmission beam is increased, the reception power of the mobile station as the transmission subject is increased although the peak direction of the transmission beam is slightly deviated from the mobile station.

Therefore, such a reduction in the increase in the transmission power caused when the peak direction of the transmission beam deviates from the mobile station as the transmission object causes a reduction in the interference power applied to other mobile stations located in the peak direction, and a decrease in the system subscriber capacity can be prevented.

Drawings

Fig. 1 is a block diagram showing a structure of an adaptive antenna transceiving apparatus of the related art;

fig. 2 is a block diagram showing the structure of a first embodiment of the adaptive antenna transceiving apparatus of the present invention;

fig. 3A is a diagram illustrating a change in transmission power during application of TPC when a peak direction of a transmission beam is directed to a mobile station;

fig. 3B is a diagram illustrating a change in transmission power during application of TPC when the peak direction of a transmission beam is deviated from a mobile station;

fig. 4 is a diagram showing a transmission beam control method of the adaptive antenna transceiving apparatus of the first embodiment;

FIG. 5 is a flowchart illustrating a procedure of the transmission beam control method illustrated in FIG. 4;

fig. 6 is a diagram showing a transmission beam control method of the adaptive antenna transceiving apparatus of the second embodiment;

FIG. 7 is a flowchart illustrating a procedure of the transmission beam control method illustrated in FIG. 6;

FIG. 8 is a flowchart showing the procedure of a transmission beam control method of the third embodiment;

fig. 9 is a block diagram showing the structure of an adaptive antenna transceiving apparatus of the fourth embodiment; and

fig. 10 is a block diagram showing an example of the structure of a radio base station having the adaptive antenna transceiving apparatus of the present invention.

Detailed Description

The invention is explained below with reference to the drawings.

First embodiment

As shown in fig. 2, the transceiving apparatus of the first embodiment includes: a plurality of (N, where N is a positive integer) antenna devices 101_1 to 101_ N arranged in an array; reception-side multipliers 102_1 to 102_ N for multiplying reception antenna weights by reception signals that have been received by the antenna devices 101_1 to 101_ N; an adder 103 for adding (synthesizing) a plurality of reception signals that have been multiplied by the reception antenna weights, and supplying the result as reproduction data; a reception antenna weight generation circuit 104 for calculating optimum reception antenna weights to be multiplied by the reception signals that have been received, based on the reproduction data that has been supplied as the output of the adder 103, and supplying these optimum reception antenna weights to the respective reception-side multipliers 102_1 to 102_ N; a TPC bit decoding circuit 107 for extracting TPC bits from the reproduced data and decoding an instruction for increasing or decreasing transmission power; a TPC bit monitoring circuit 108 for monitoring, at prescribed time intervals, changes of the increase or decrease transmission power command that has been decoded by the TPC bit decoding circuit 107 and detecting whether there is a bias (bias) for increasing the transmission power command; an antenna weight converting circuit 105 for generating a first transmit antenna weight based on the receive antenna weight that has been generated by the receive antenna weight generating circuit 104; a transmission antenna weight control circuit 109 for controlling the first transmission antenna weight based on the monitoring result of the TPC bit monitoring circuit 108 and providing the result as a second transmission antenna weight; and transmission-side multipliers 106_1 to 106_ N for multiplying the second transmission antenna weights, which have been supplied as outputs of the transmission antenna weight control circuit 109, by transmission data and supplying the products to the antenna devices 101_1 to 101_ N.

As in the related art, the adaptive antenna transceiving apparatus shown in fig. 2 shows the structure of a baseband signal processor, which is mainly used to implement signal processing of baseband transceiving data. The adaptive antenna transceiving apparatus comprises a radio signal transceiver (not shown) provided with: an RF receiver for converting radio frequency signals, which have been received by the antenna devices 101_1-101_ N, into baseband signals; and an RF transmitter for converting the baseband signal into a radio frequency signal. The baseband signal processor may be constituted by a semiconductor integrated device that realizes the function of each of the above-described components by, for example, a logic circuit or the like, or may be constituted by a DSP or a CPU. When the baseband signal processor is configured by a DSP or a CPU, each component other than the antenna device performs the following processing according to a program stored in advance in the storage device.

For example, the reception antenna weight generation circuit 104 performs MMSE (minimum mean square error) processing, updating reception antenna weights so as to minimize a mean square error between reproduced data, which has been supplied as an output of the reception-side adder 103, and a predetermined reference signal (desired signal waveform). Algorithms such as LMS (least mean square) algorithm or RLS (recursive least square) algorithm are well-known algorithms for implementing MMSE processing, and no particular limitation is set on the algorithm used in the reception antenna weight generation circuit 104 of the present embodiment.

The reception antenna weight W generated in the reception antenna weight generation circuit 104 is equal to (W)₁，w₂，...，w_N) To each of the receiving-side multipliers 102_1 to 102_ N and the antenna weight switching circuit 105.

The antenna weight switching circuit 105 sets (W) based on the reception antenna weight W generated in the reception antenna weight generating circuit 104₁，w₂，...，w_N) Generating a transmit antenna weight (first transmit antenna weight) W ═ W'₁，w′₂，...，w′_N). The antenna weight conversion circuit 105 is a device provided correspondingly to each antenna device for performing a process of correcting an amplitude/phase deviation between a plurality of radio signal transceivers (not shown in fig. 2) or a process of correcting a difference between frequencies when the frequencies of a transmission wave and a reception wave are different as in a well-known FDD (frequency division duplex) system. Antenna weight conversion circuit 105 generates first transmit antenna weight W ═ W'₁，w′₂，...，w′_N) A transmission beam having substantially the same directivity as during reception is formed.

The TPC bit decoding circuit 107 extracts TPC bits from the reproduced data and supplies decoded increase/decrease transmission power commands that have been transmitted from the mobile station.

The TPC bit monitoring circuit 108 monitors a change in the increase/decrease transmission power command, which has been decoded by the TPC bit decoding circuit 107, within a prescribed time interval. When the peak direction of the transmission beam is correctly directed to the desired wave mobile station, it is assumed that the TPC bit decoding result is sequentially repeated between the decrease transmission power command and the increase transmission power command. In other words, the transmission power from the radio base station to the desired wave mobile station repeatedly increases and decreases centering on a specific transmission power (threshold power) within a prescribed time interval that has been determined in advance, as shown in fig. 3A. In this case, the number of increase instructions and the number of decrease instructions in the TPC bits are substantially the same within the prescribed time interval.

On the other hand, if the peak direction of the transmission beam deviates from the direction of the desired wave mobile station, it is assumed that the desired wave mobile station will continuously request the radio base station to increase the transmission power until the desired reception quality is obtained, and will continuously provide an increase instruction as an output of the decoding result of the TPC bits. In other words, the transmission power from the radio base station to the desired wave mobile station will be increased continuously step by step over a prescribed time interval, as shown in fig. 3B. In this case, the desired-wave mobile station finally obtains the desired reception quality, but other mobile stations located in the peak direction of the transmission beam formed by the radio base station directly receive unnecessary interference power, and therefore, the reception quality will be greatly deteriorated.

As a countermeasure against this problem, in the present embodiment, when the result of decoding the TPC bits within the predetermined time interval is biased toward increasing the transmission power command, the transmission antenna weight control circuit 109 shifts the peak direction of the transmission beam to the left and right. More specifically, the second transmit antenna weight W ″ ═ (W ″ ") is generated₁，w″₂，...，w″_N) Thus W 'is weighted for the first transmit antenna'₁，w′₂，...，w′_N) The resulting emitted beam shifts the peak direction to the right or to the left. These second transmit antenna weights increase or decrease the amplitude of the transmit data to thereby control the peak direction of the transmit beam. This process is performed until the decoding of the TPC bit knots are eliminatedIf there is a bias towards an instruction to increase the transmission power, or until the number of movements in the direction of the peak reaches a maximum value that has been set in advance. The transmission antenna weight control circuit 109 of the present embodiment is provided with a register for holding a value of each of an angle value L, which is a unit of movement when the peak direction is shifted to the right or left, a variable K (initial value ═ 0) representing the number of movements, and Kmax, which is the maximum number of changes (maximum value of the number of movements).

The structures and operations of the receiving-side multipliers 102_1 to 102_ N, the adder 103, the receiving antenna weight generating circuit 104, and the transmitting-side multipliers 106_1 to 106_ N are the same as those of the related art adaptive transceiving apparatus shown in fig. 1, and thus, explanations of the structures and operations thereof are omitted here.

Referring to fig. 4 and 5, a method of controlling a transmission beam using the adaptive antenna transceiving apparatus of the present embodiment is explained below.

As shown in fig. 4, in the adaptive antenna transceiver device of the present embodiment, when the result of decoding TPC bits within a prescribed time interval is biased toward increasing the transmission power command, W ═ is weighted for the first transmission antenna'₁，w′₂，...，w′_N) The direction (initial direction) of the formed transmission beam 3, the peak direction, is shifted to the right (or left) by a predetermined angle L ("a" of fig. 4). Then, if the situation is not improved (the result of decoding the TPC bits is biased toward increasing the transmission power command), the peak direction is further shifted to the right (or left) by an angle L ("b" of fig. 4). The same process is repeated until the maximum number of changes Kmax that has been set in advance is reached.

If the situation is not improved, although the maximum change number Kmax of the peak direction movement of the transmission beam has been reached, the peak direction is moved to the left (or right) by the angle L of a plurality of units in the opposite direction ("c", "d", "e", and "f" of fig. 4). Here, the maximum number of changes in the opposite direction is 2 Kmax.

Through the above-described processing, the peak direction of the transmission beam moves within the maximum range of ± Kmax × L ("+" is to the right, and "-" is to the left) degrees. The values of Kmax and L of L can be changed to arbitrary values by an external instruction. Fig. 4 shows an example in which Kmax is set to 2, in which the peak direction returns to the original initial position ("g" and "h" of fig. 4) after moving twice in units of an angle L to the right and four times in units of an angle L to the left.

As shown in fig. 5, the transmission antenna weight control circuit 109 of the present embodiment, upon receiving the decoding result from the TPC bit monitoring circuit 108, first resets the variable K indicating the number of shifts in the peak direction to "0" (step S1), and then determines whether the result of decoding the TPC bit transmitted from the mobile station has a bias toward an instruction to increase the transmission power (step S2). If the result of decoding the TPC bits is biased toward increasing the transmission power command, the transmission antenna weight control circuit 109 weights the second transmission antenna by W ″ (W ″)₁，w″₂，...，w″_N) Is set so that the peak direction of the transmission beam is shifted rightward (or leftward) by L degrees (step S3). The transmission antenna weight control circuit 109 also increments the value of the variable K indicating the number of times of peak direction movement by "1" (step S4). If the result of decoding the TPC bits has a bias toward an instruction to reduce the transmission power or if there is no bias in any direction, the transmission antenna weight control circuit 109 supplies the first transmission antenna weight that has been generated by the antenna weight switching circuit 105 without changing to the second transmission antenna weight, and interrupts the control processing of the transmission beam of the present embodiment.

Next, the transmission antenna weight control circuit 109 determines whether the value of the variable K has reached the maximum number of changes Kmax (step S5), and if the value has not reached the maximum number of changes Kmax, returns to the processing of step S2, and repeats the processing of steps S2 to S5.

When the value of the variable K reaches the maximum change number Kmax, the transmission antenna weight control circuit 109 determines whether or not the result of decoding the TPC bits that have been transmitted from the mobile station has a transmission toward the increase after resetting the value of the variable K (step S6)The command for the transmission power is biased (step S7). If there is a bias toward an instruction to increase the transmission power in the result of decoding the TPC bits, the transmission antenna weight control circuit 109 weights the second transmission antenna W ″ (W ″)₁，w″₂，...，w″_N) Is set so that the peak direction of the transmission beam is shifted to the left (or right) (the opposite direction from the present) by L degrees (step S8). The transmission antenna weight control circuit 109 also increments the value of the variable K indicating the number of movements in the peak direction by "1" (step S9). If the result of decoding the TPC bits indicates a bias toward an instruction to reduce the transmission power or no bias in any direction, the transmission antenna weight control circuit 109 supplies, as an output, the first transmission antenna weight that has been generated by the antenna weight switching circuit 105 without changing to the second transmission antenna weight, and interrupts the transmission beam control process of the present embodiment.

Next, the transmission antenna weight control circuit 109 determines whether the value of the variable K has reached the maximum change number 2Kmax that has been set in advance (step S10), and if the value has not reached the maximum change number 2Kmax, returns to the processing of step S7, and repeats the processing of steps S7 to S10. If the value of the variable K has reached the maximum number of changes 2Kmax, the transmission antenna weight control circuit 109 supplies the first transmission antenna weight, which has been generated by the antenna weight conversion circuit 105, as an output without changing to the second transmission antenna weight, and interrupts the transmission beam control process of the present embodiment.

In fig. 4 and 5, examples are shown in which the peak directions of the transmitted beams are shifted to the right and left by an angle L of several units, and the shift angle may be an integral multiple of the angle L (except for zero), which is set in advance. For example, when the peak direction of the transmission beam is at the position + Kmax × L or-Kmax × L, the peak direction may be moved to the initial position in one operation.

According to the adaptive antenna transceiving apparatus of the present embodiment, if the result of decoding the TPC bits within the prescribed time interval indicates a bias toward an instruction to increase the transmission power, the peak direction of the transmission beam can be corrected to the direction of the desired-wave mobile station by shifting the peak direction of the transmission beam to the right or left. Accordingly, the present embodiment can reduce interference power applied to other mobile stations located in the peak direction due to deviation of the peak direction of the transmission beam from the mobile station as the transmission object, and thus can prevent reduction in system subscriber capacity.

Second embodiment

In the adaptive antenna transceiving apparatus of the second embodiment, the transmission beam control procedure of the transmission antenna weight control circuit 109 is different from that of the first embodiment. The other structures and operations are the same as those of the first embodiment, and redundant explanation is omitted.

As shown in fig. 6, in the adaptive antenna transceiving apparatus of the second embodiment, the following processing is performed by the transmission antenna weight control circuit 109: when the result of decoding the TPC bits within the prescribed time interval indicates a bias toward an instruction to increase the transmission power, the peak direction of the transmission beam 3 is alternately shifted to the left and right. In this embodiment, W 'is weighted for the first transmit antenna'₁，w′₂，...，w′_N) The transmission beam 3 is formed to shift the peak direction to the right (or left) by the angle L ("a" of fig. 6) that has been set in advance. If the situation is not improved (the result of decoding the TPC bits indicates a bias towards an instruction to increase the transmission power), the peak direction is shifted to the left (or right) by an angle 2L ("b" of fig. 6). If the situation is not improved yet, the peak direction is shifted to the right (or left) by an angle 3L ("c" of FIG. 6). The same process is repeated again. In this case, assuming that the maximum number of changes is 2Kmax, the setting has been made in advance.

The transmission antenna weight control circuit 109 of the present embodiment is provided with a register for holding the value of each of an angle L, a variable J, a variable K, and Kmax, in which the peak direction of the angle L is a unit of movement when moving to the right and left; the variable J (a positive integer, initial value 1) is used to multiply the angle L; the variable K (initial value ═ 0) represents the number of moves; and the Kmax is the maximum number of changes (maximum number of moves).

The above-described processing causes the peak direction of the transmission beam to vary within a maximum range of ± Kmax × L (where "+" is to the right and "-" is to the left) degrees. The values of Kmax and L can be changed to arbitrary values by an external instruction. Fig. 6 shows an example in which Kmax has been set to 2.

As shown in fig. 7, in obtaining the decoding result of the TPC bit monitoring circuit 108, the transmission antenna weight control circuit 109 of the second embodiment first resets the value of the variable K indicating the number of times the peak direction has been shifted to "0", and then sets the value of the variable J that multiplies the angle L to "1" (step S11).

Next, the transmission antenna weight control circuit 109 determines whether the result of decoding the TPC bits transmitted from the mobile station is biased toward increasing the transmission power command (step S12), and if the result of decoding the TPC bits is biased toward increasing the transmission power command, the transmission antenna weight control circuit 109 weights the second transmission antenna W ″ (W ″)₁，w″₂，...，w″_N) Is set so that the peak direction of the transmission beam is shifted by + J × L (or-J × L) (step S13). Next, the transmission antenna weight control circuit 109 increments the value of each of the variable K indicating the number of times of peak direction shift and the variable J for multiplying the angle L by "1", and multiplies the angle L by-1 (step S14). If the result of decoding the TPC bits is biased toward an instruction to decrease the transmission power, or if the result is biased neither toward an increase nor toward a decrease, the transmission antenna weight control circuit 109 supplies, as an output, the first transmission antenna weight that has been generated by the antenna weight switching circuit 105 without changing to the second transmission antenna weight, and interrupts the transmission beam control process of the present embodiment.

Next, the transmission antenna weight control circuit 109 determines whether the value of the variable K has reached the maximum change number 2Kmax set in advance (step S15), and if the value of the variable K has not reached the maximum change number 2Kmax, the transmission antenna weight control circuit 109 returns to the process of step S12 and repeats the processes of steps S12 to S15. However, if the value of the variable K has reached the maximum number of changes 2Kmax, the transmission antenna weight control circuit 109 supplies the first transmission antenna weight, which has been generated by the antenna weight conversion circuit 105, as an output without changing to the second transmission antenna weight, and interrupts the control processing of the transmission beam of the present embodiment.

The adaptive antenna transceiving apparatus of the second embodiment can correct the peak direction of the transmission beam to the direction of the desired wave mobile station, as in the first embodiment, and therefore can reduce the interference power applied to other mobile stations in the peak direction caused when the peak direction of the transmission beam deviates from the mobile station as the transmission object. Therefore, the adaptive antenna transceiving apparatus of the second embodiment can prevent a reduction in the system subscriber capacity.

Third embodiment

In the adaptive antenna transceiving apparatus of the third embodiment, the transmission beam control procedure of the transmission antenna weight control circuit is different from the first embodiment and the second embodiment. The other structures and operations are the same as those of the first embodiment, and redundant explanation is omitted.

In the adaptive antenna transceiving device of the third embodiment, when the result of decoding the TPC bits is biased toward increasing the transmission power command, W '═ W'₁，w′₂，...，w′_N) The resulting transmitted beam increases the width of the main lobe by a preset angle of + -H (where "+" is to the right and "-" is to the left). If the situation is not improved (if the result of decoding the TPC bits is still biased towards the instruction to increase the transmit power), the main lobe width of the transmit beam is again increased by the angle H. The same process is then repeated. In this case, the maximum number of changes is set to Kmax.

The above process varies the main lobe width of the transmission beam within the maximum range of Kmax × 2H degrees. When the main lobe width of the transmission beam is increased in this manner, even if the peak direction of the transmission beam is slightly deviated from the mobile station as the transmission object, the reception power of the mobile station is increased, and therefore, the increase of the transmission power due to the deviation of the peak direction of the transmission beam from the mobile station as the transmission object is restricted. Further, since excessive increase of the main lobe width applies interference power to other mobile stations located near the desired wave mobile station in the present embodiment, it is preferable to set the angle H and the maximum number of changes Kmax to minimum values.

The transmission antenna weight control circuit 109 of the present embodiment is provided with a register for holding the value of each of an angle H, which is a main lobe width change unit, a variable K, and Kmax; the variable K represents the number of main lobe width changes; and Kmax is the maximum number of changes. The values of Kmax and H may be changed to arbitrary values according to an external instruction.

As shown in fig. 8, in obtaining the decoding result from the TPC bit monitoring circuit 108, the transmission antenna weight control circuit 109 of the present embodiment first resets the value of the variable K indicating the number of times of change of the main lobe width to "0" (step S21), and then determines whether the result of transmission of the decoded TPC bits transmitted from the mobile station is biased toward an increase of the transmission power command (step S22). If the result of decoding the TPC bits is biased toward increasing the transmission power command, the transmission antenna weight control circuit 109 weights the second transmission antenna by W ″ (W ″)₁，w″₂，...，w″_N) Is set so that the main lobe width of the transmission beam is increased by ± H degrees (step S23). The transmission antenna weight control circuit 109 also increments the value of a variable K indicating the number of times the main lobe width is changed by "1" (step S24). If the result of decoding the TPC bits is biased toward an instruction to decrease the transmission power, or if the result is biased neither toward an increase nor toward a decrease in the transmission power, the transmission antenna weight control circuit 109 supplies the first transmission antenna weight, which has been generated by the antenna weight switching circuit 105, as an output without changing to the second transmission antenna weight, and interrupts the transmission beam control process of the present embodiment.

Next, the transmission antenna weight control circuit 109 determines whether the value of the variable K has reached the maximum change number Kmax set in advance (step S25), and if the value of the variable K has not reached the maximum change number 2Kmax, the transmission antenna weight control circuit 109 returns to the process of step S22 and repeats the processes of steps S22 to S25. In contrast, if the value of the variable K has reached the maximum number of changes Kmax, the transmission antenna weight control circuit 109 supplies the first transmission antenna weight, which has been generated by the antenna weight conversion circuit 105, as an output without changing to the second transmission antenna weight, and interrupts the control process of the transmission beam of the present embodiment.

The adaptive antenna transceiving apparatus of the third embodiment limits an increase in transmission power caused when the peak direction of the transmission beam deviates from the mobile station that is the transmission object, and therefore, can reduce interference power applied to other mobile stations located in the peak direction of the transmission beam, and can prevent a reduction in system subscriber capacity.

Fourth embodiment

In the first to third embodiments, examples are shown in which the peak direction of the transmission beam is controlled by increasing or decreasing the amplitude of the transmission data with the second transmission antenna weight.

However, the adaptive antenna transceiving apparatus may also control the transmission power using the above-described radio signal transceiver. The radio signal transceivers 210_1 to 210_ N are provided with: an RF transmitter, a quadrature modulator for quadrature-modulating a baseband signal, an up-converter for converting the baseband signal into a radio frequency signal, an AGC (automatic gain control), and a TPA (transmission power amplifier) (these components are not shown in the drawing); and as shown in fig. 9, radio signal transceivers 210_1-210_ N are arranged between the antenna device and the transmit-side multiplier.

In the present embodiment, the monitoring result of the TPC bit monitoring circuit is supplied to the radio signal transceivers 210_1 to 210_ N, and the power supplied to each antenna device is controlled by, for example, the AGCs provided in the radio signal transceivers 210_1 to 210_ N, as with the transmission antenna weight control circuits shown in the first to third embodiments. This structure can obtain the same effects as those of the first to third embodiments.

Fifth embodiment

Fig. 10 is a block diagram showing an example of the structure of a radio base station provided with the adaptive antenna transceiving apparatus of the present invention.

As shown in fig. 10, the radio base station 1 of the present embodiment has a structure including: the adaptive antenna transceiving apparatus 11 shown in the first to fourth embodiments; a control unit 12 for controlling operations of the radio base station such as multiplexing and demultiplexing of transmission data of each mobile station and monitoring a communication state with each mobile station; and a communication interface device 13 as an interface with the radio network control device 2 for controlling the position of each mobile station by the plurality of radio base stations 1 and relaying communication between the mobile station and the network.

As in the present embodiment, using the adaptive antenna transceiving equipment 11 shown in the first to fourth embodiments in the radio base station 1 realizes a radio base station capable of preventing a reduction in the capacity of a mobile communication system subscriber.

Claims

1. A transmission beam control method for controlling a transmission beam of an adaptive antenna transceiving apparatus provided with a plurality of antenna apparatuses, the method comprising:

a first step of extracting TPC bits for controlling transmission power from a reception signal having been received through the plurality of antenna devices, and decoding an increase/decrease instruction for instructing an instruction to increase the transmission power or an instruction to decrease the transmission power from the TPC bits;

a second step of monitoring a change in the increase/decrease instruction for a prescribed time interval that has been set in advance, and determining whether the increase/decrease instruction is biased toward increasing the transmission power instruction;

a third step of shifting a peak direction of the transmission beam in an angle unit that has been set in advance according to the same directivity as during reception when the increase/decrease instruction is biased toward the instruction for increasing the transmission power; and

a fourth step of repeating the first to third steps until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of times of movement of the transmission beam reaches a maximum value that has been set in advance.

2. The transmission beam control method according to claim 1, characterized in that: the peak direction of the transmission beam is shifted by an integral multiple of the angle that has been set in advance, except for zero.

3. A transmission beam control method for controlling a transmission beam of an adaptive antenna transceiving apparatus provided with a plurality of antenna apparatuses, the method comprising:

a third step of increasing a main lobe width of the transmission beam in angle units that have been set in advance when the increase/decrease instruction is biased toward an instruction for increasing the transmission power; and

a fourth step of repeating the first to third steps until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of increases of the main lobe width of the transmission beam reaches a maximum value that has been set in advance.

4. An adaptive antenna transceiving apparatus that controls transmission power and directivity of a transmission beam using a plurality of antenna apparatuses, the adaptive antenna transceiving apparatus comprising:

a TPC bit decoding circuit for extracting TPC bits for controlling transmission power from the reception signals which have been received through the plurality of antenna devices, and decoding an increase/decrease instruction for instructing an instruction to increase the transmission power or an instruction to decrease the transmission power from the TPC bits;

a TPC bit monitoring circuit for monitoring a change in the increase/decrease command that has been decoded by the TPC bit decoding circuit for a prescribed time interval and determining whether the increase/decrease command is biased toward a command to increase the transmission power; and

a transmission antenna weight control circuit that, when the increase/decrease instruction is biased toward an instruction to increase the transmission power, generates a transmission antenna weight corresponding to an amplitude supplied to each of the antenna devices so as to move a peak direction of the transmission beam in an angle unit that has been set in advance in accordance with the same directivity as during reception; and repeating the process of moving the peak direction of the transmission beam until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of times the transmission beam has been moved reaches a preset maximum value.

5. The adaptive antenna transceiving apparatus of claim 4, wherein: the transmission antenna weight control circuit controls the transmission antenna weights so that the peak directions of the transmission beams are shifted by integer multiples of an angle that has been set in advance, excluding zero.

6. An adaptive antenna transceiving apparatus that controls transmission power and directivity of a transmission beam using a plurality of antenna apparatuses, the adaptive antenna transceiving apparatus comprising:

a transmission antenna weight control circuit that, when the increase/decrease instruction is biased toward an instruction to increase the transmission power, generates transmission antenna weights each corresponding to an amplitude supplied to each of the antenna devices so that a main lobe width of the transmission beam increases in a prescribed angle unit from a value that has been set in advance; and repeating the process of increasing the main lobe width of the transmission beam until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of increases in the main lobe width of the transmission beam reaches a preset maximum value.

7. An adaptive antenna transceiving apparatus that controls transmit power of a transmit beam using a plurality of antenna apparatuses, the adaptive antenna transceiving apparatus comprising:

a radio signal transceiver that controls power supplied to each of the antenna devices so that a peak direction of the transmission beam is moved in angle units that have been set in advance according to the same directivity as during reception, when the increase/decrease command is biased toward a command to increase the transmission power; and repeating the process of moving the peak direction of the transmission beam until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of times of movement of the transmission beam reaches a preset maximum value.

8. The adaptive antenna transceiving apparatus of claim 7, wherein: the radio signal transceiver controls power supplied to each of the antenna devices so that the peak directions of the transmission beams are shifted by integer multiples of an angle that has been set in advance, except for zero.

9. An adaptive antenna transceiving apparatus that controls transmit power of a transmit beam using a plurality of antenna apparatuses, the adaptive antenna transceiving apparatus comprising:

a radio signal transceiver that controls power supplied to each of the antenna devices so that a main lobe width of the transmission beam increases in a prescribed angle unit from a value that has been set in advance, when the increase/decrease instruction is biased toward an instruction to increase the transmission power; and repeating the process of increasing the main lobe width of the transmission beam until the deviation of the increase/decrease instruction to the instruction to increase the transmission power is eliminated or until the number of increases in the main lobe width of the transmission beam reaches a preset maximum value.

10. A radio base station, comprising:

the adaptive antenna transceiving apparatus of claim 4;

a control unit for monitoring a communication state with each mobile station and multiplexing/demultiplexing transmission/reception data of each mobile station; and

a communication interface device for interfacing with a radio network control device for relaying communication between the mobile station and a network.

11. A radio base station, comprising:

the adaptive antenna transceiving apparatus of claim 6;

12. A radio base station, comprising:

the adaptive antenna transceiving apparatus of claim 7;

13. A radio base station, comprising:

the adaptive antenna transceiving apparatus of claim 9;