JP3455448B2 - Beam control antenna device and antenna control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam control antenna device and an antenna control method which are used in a wireless communication base station or the like to form a desired antenna beam according to the situation.

[0002]

2. Description of the Related Art An omnidirectional antenna (FIG. 6) that uniformly radiates a beam in all angular regions in a horizontal plane or a sector beam antenna that radiates a beam in a certain angular region as an antenna for a base station in radio communication such as a mobile phone (Figure 7)
Is generally used.

Since these conventional methods have the advantage that the antenna configuration is simple and the user can communicate with any user (terminal) in the irradiation area because the beam shape itself is fixed, it is possible to communicate with the user. Since the antenna beam is fixed in communication, the gain is limited, the line gain cannot be increased, and the irradiation area cannot be widened. In particular, radio waves are radiated to the direction other than the user who communicates when transmitting from the base station. Therefore, there is also a problem that it interferes with communication within the area of other users and other base stations.

As a means for solving such a problem, it is considered to use an adaptive array antenna as shown in FIG. 8 in a base station. As shown in FIG. 9, the adaptive array antenna has an advantage that an optimum antenna beam pattern can be adaptively formed for a specific user who performs communication according to the radio wave propagation environment at that time. For example, as shown in FIG. 9, the beam can be directed so as to form the maximum gain in the direction of the users, and a null (zero point) can be formed in the direction of the radio wave that causes interference in the communication between the users. You can

Therefore, the line gain for a specific user can be maximized, the communication area of the base station can be widened, and the base station does not emit radio waves in unnecessary directions, so that the communication system can be used. There is an effect of suppressing interference as a whole, and communication quality can be improved.

In order to form such a beam, it is necessary to perform signal processing for optimizing the weighting amount set for each antenna so as to form an optimum beam based on the signal received by each antenna element. become.

In practice, this signal processing converts the received signal at each antenna into a digital signal,
It is generally calculated by a signal processing device such as an ignal processor).

[0008]

However, in the conventional adaptive array antenna, the signal processing algorithm for determining some weighting amount is used until the weighting amount set for each antenna is optimized. There is a problem that the value does not converge unless it is calculated and repeated several times.

Particularly, when the transmission speed of communication is high,
There is a situation where the solution does not converge sufficiently and a good antenna beam pattern cannot be formed, or the communication data up to that point has to be discarded due to the time it takes for the solution to converge. .

In order to cope with a high transmission speed, a method of speeding up the signal processing circuit by operating a plurality of DSPs of the highest level in parallel can be considered, but in this case, the signal processing circuit is very complicated. It becomes expensive and power consumption becomes large.

The present invention has been made in order to solve such a problem, and in radio communication of high speed transmission, an optimum antenna beam pattern can be easily and quickly obtained by a simple and inexpensive signal processing circuit. It is an object to provide a beam control antenna device and an antenna control method realized by processing.

The beam control antenna device of the present invention includes a plurality of antenna elements, a weighting means for setting a predetermined weighting amount for signals transmitted and received by each antenna element, and each antenna element. A storage unit that stores a plurality of weighting vectors configured by each weighting amount that is set, a measurement unit that measures the communication channel characteristics in the state where one of the weighting vectors is set, and a measurement unit that measures A weighting vector that realizes a communication channel characteristic based on a predetermined evaluation criterion from the communication channel characteristic is provided with a selecting unit that selects from a plurality of weighting vectors, and corresponds to the weighting vector selected by the selecting unit during communication. The weighting amount to be set is set for a plurality of antenna elements.

With the above configuration, the weighting vector is stored in the storage device in advance, the weighting vector is sequentially called from this storage device before communication, and the weighting amount corresponding to this weighting vector is set in each antenna element. , At that time, measure the communication channel characteristics, determine the optimal weighting vector for each user based on this measurement value according to some evaluation criteria, and during communication, assign the weighting amount corresponding to this optimal weighting vector to each antenna element. Can be set.

Further, the beam control antenna apparatus of the present invention further comprises detection means for detecting the reception intensity of the received signal, and the selection means sets the weighting vector when the reception intensity detected by the detection means is maximum. , Characterized by selecting.

With the above-mentioned configuration, each reception intensity at the base station side when each weighting vector is set can be measured by the reception device at the subsequent stage of the beam control antenna device.
Based on this reception intensity, a weighting vector that realizes the maximum reception intensity can be selected and set at the time of communication.

Further, the beam control antenna device of the present invention further comprises receiving means for receiving the reception intensity of the signal detected by another communication device which has received the transmitted signal, and the selecting means comprises the receiving means. It is characterized in that a weighting vector when the reception intensity received in step 1 is maximized is selected.

With the above-mentioned configuration, the reception intensity of each communication partner when each weighting vector is set can be measured by the receiver of the communication partner, and the measured value can be transmitted to the base station side. In, the weighting vector that realizes the maximum reception strength can be selected based on this reception strength, and this can be set during communication.

Further, the beam control antenna device of the present invention is
A plurality of antenna elements, a weighting means for setting a predetermined weighting amount for signals transmitted and received by each antenna element, and a storage means for storing a plurality of weighting vectors configured by the weighting amounts set for each antenna element , Communication transmission in a state in which one of a plurality of weighting vectors is set between a registration unit that registers another communication device that communicates with this device and another communication device that is registered by the registration unit Measuring means for measuring the road characteristics,
A weighting vector that realizes a communication channel characteristic based on a predetermined evaluation criterion from the communication channel characteristic measured by the measuring unit, and a selecting unit that selects from a plurality of weighting vectors. The weighting amount corresponding to the weighted vector is set for a plurality of antenna elements.

With the above configuration, a plurality of weighting vectors obtained in advance by a method such as computer simulation are stored in the weighting vector storing step, and a communication partner with whom communication is possible may be stored in the user registration step. When a certain user is registered, the stored weighting vectors are sequentially called from the storage device and set, and the transmission line characteristics at that time are grasped by measuring the transmission line characteristics to determine the transmission line characteristics of each user and each weighting vector. You can create a table.

Based on this table, it becomes possible to grasp in advance the optimum weighting vector that realizes the best transmission characteristic for each user. next,
In the optimum antenna pattern setting step at the time of communication, the optimum line state can be realized at the time of communication by setting the optimum weighting vector obtained from the table.

Further, in the beam control antenna device of the present invention, when a plurality of communication devices are registered, the selecting means is
It is characterized in that a weighting vector that minimizes mutual interference in communication with a plurality of registered communication devices is selected from the plurality of weighting vectors.

With the above-mentioned structure, the table is used to obtain a combination of users who can communicate without interfering with each other even if they simultaneously communicate, and an optimum weighting vector set for each user in that case. You can Also, when a plurality of users try to communicate at the same time, it can be determined that there is a possible combination of the same frequency or the same channel among the plurality of users, and in that case, the same frequency or the same channel is set for the user. be able to.

Further, the antenna control method of the present invention includes a first step of selecting one from a memory in which a plurality of weighting vectors configured by respective weighting amounts set for each of a plurality of antenna elements are stored, and the selection step. Second step of setting the respective weighting amounts of the plurality of antenna elements by the weighted weighting vector, the third step of measuring the communication channel characteristic in the state of being weighted by the weighting vector, and the third step. Is performed a plurality of times based on a plurality of weighting vectors, and a plurality of measured communication transmission line characteristics are compared, the communication transmission line characteristic is determined based on a predetermined evaluation criterion, and this communication transmission line characteristic is realized. And a fifth step of determining the weighting of the antenna element with a weighting vector.

Further, the antenna control method of the present invention comprises a first step of selecting one from a memory in which a plurality of weighting vectors constituted by respective weighting amounts set for each of a plurality of antenna elements are stored, and the present apparatus. Between a second step of registering another communication device that communicates with the communication device and another communication device registered by the second step.
A third step of measuring the communication transmission line characteristics in the state of being weighted by the weighting vector selected in the step, a fourth step of performing the third step a plurality of times based on a plurality of weighting vectors, and a plurality of the measured plurality of weighting vectors. A fifth step of comparing the communication transmission line characteristics, determining the communication transmission line characteristic based on a predetermined evaluation criterion, and determining the weighting of the antenna element with the weighting vector that realizes this communication transmission line characteristic. Characterize.

[0024]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a beam control antenna apparatus according to the first embodiment of the present invention. As an example, a case where the four antenna elements 11, 12, 13, and 14 are shared for transmission and reception will be described.

Switches 21, 22, 23, 24 are connected to the antenna elements 11, 12, 13, 14 respectively, and switching between transmission and reception is performed by these switches. Here, in the receiving system, the received signals from the respective antenna elements are respectively input to amplifiers (low noise amplification) 35, 36, 37, 38,
Here, the received signal is amplified.

After that, frequency converters 45, 46, 47, 4
8, the frequency band of the received signal is converted from the radio frequency (RF) to the intermediate frequency (IF) or the base band (BB).
In this IF band or BB band, weighting devices 55, 56,
The signals received from each antenna element are weighted by 57 and 58.

Here, as the weighting by the weighter, amplitude weighting for changing only the amplitude component of the received signal,
It is possible to select three types of phase weighting that changes only the phase component of the received signal and complex weighting that changes both the amplitude and the phase.

A variable amplifier or a variable attenuator can be used as the amplitude weighting method, and a variable phase shifter can be used as the phase weighting method. In the case of complex weighting, these may be combined.

The above is the case where the received signal is an analog signal, but it is also possible to perform weighting in the digital signal domain by using an analog / digital (A / D) converter or the like. In the present invention, any weighting method may be used as long as it has a means for weighting the received signal of each antenna element. Then, the weighted received signals are combined by the combiner 62 and transmitted to the receiver.

In the transmission system, the transmission signal transmitted from the transmitter is distributed by the distributor 61, and the respective transmission signals are individually weighted. The weighting means is the same as in the case of the receiving system, and the weighting means 51,
Weighted by 52, 53, 54.

The respective transmission signals are transmitted to the frequency converter 4 respectively.
The frequency is converted to the RF band by 1, 42, 43 and 44, and is amplified by amplifiers (high output amplifiers) 31, 32, 33 and 34. Similar to the receiving system, the weighting means uses the intermediate frequency (I
It may be performed in F) or in baseband (BB).

The weighting amount set in reception and transmission is controlled by the weighting control device 50. Here, a feature of the present invention is that a plurality of combinations of weighting amounts (weighting vectors) to be set for each antenna element are prepared in advance and stored in the storage device 49. Therefore, in the beam control antenna device of the present invention, the weighting vector that is stored in the storage device is extracted, and the operation of actually performing weighting by the weighting device based on this is repeated one after another to realize optimum characteristics. You can select a vector.

With the above-mentioned configuration, the one which realizes the optimum characteristic can be selected from a plurality of weighting vectors by a simple process. Optimize the weighting amount by some algorithm like the conventional adaptive array,
It does not take time for the weighting amount to converge.

Therefore, there is an advantage that the structure of the weighting control circuit is simplified and the processing time is short. In particular, it is effective when high-speed wireless communication systems require real-time processing.

On the other hand, unlike the conventional adaptive array, it seems that the weighting amount is not mathematically optimized, so that the optimum characteristic may not be realized. It is possible to obtain sufficiently good characteristics for practical use by calculating the weighting vector of 1 based on computer simulation or the like.

A specific method for selecting the weighting vector that realizes the optimum characteristic will be described below. Here, as the optimum characteristics, those that increase the strength of the transmitted / received signal, those that increase the signal-to-noise ratio (S / N), and those that reduce the error rate (BER) are considered. The measurement can be easily performed by a receiver connected to the beam control antenna device of the present invention or a receiver of a communication partner.

For example, as an optimum characteristic, in the case of the characteristic of the wireless transmission line for communication, when the maximum signal strength (signal power) received by the beam control antenna device is used as the evaluation criterion, the beam control antenna is used. This is possible by measuring the reception intensity at the receiver connected to the device.

In the beam control antenna device, the weighting vector is sequentially set, and the one that maximizes the received signal strength for each weighting vector is determined and stored as the optimum weighting vector, and the optimum weighting vector is stored during communication. It suffices to perform communication using an antenna pattern based on weighting vectors.

Also in this case, the apparatus configuration and control method can be easily realized by the conventional one, and the optimum transmission line characteristic in the receiving system can be realized. Therefore, the signal quality and the user can be improved by improving the uplink in the wireless communication system. This is effective when the capacity can be improved.

Further, as the optimum characteristic, in the characteristic of the transmission path of the wireless communication, when the maximum evaluation is the signal strength (signal power) transmitted by the beam control antenna device, the beam control antenna This is possible by measuring the reception intensity at the receiver on the radio side of the other party who communicates with the device.

In the beam control antenna device, the weighting vector is sequentially set, the transmission signal strength for each weighting vector is measured, and the value is transmitted to the beam control antenna side so that the strength is maximized. It is only necessary to determine and store an object as an optimum weighting vector, and perform communication at the time of communication with an antenna pattern based on the optimum weighting vector.

Also in this case, the apparatus configuration and control method can be easily realized by the conventional one, and the optimum transmission path characteristic in the transmission system can be realized. Therefore, the signal quality and the user can be improved by improving the downlink in the wireless communication system. This is effective when the capacity can be improved.

The specific operation of the beam control antenna device according to the first embodiment of the present invention will be described below. The operation procedure is shown below. The storage device 49 stores the weighting amounts corresponding to the plurality of antenna patterns. At the time of user registration, the transmission path characteristics for each antenna pattern are measured. Select the optimum antenna pattern for communication.

First, in connection with the procedure of FIG. 2, FIG. 2 shows an image of the weighting amount stored in the storage device 49. As shown in the figure, eight antenna patterns (weighting vectors) are prepared in advance, and the weighting amount (amplitude weighting and phase weighting) for each antenna element corresponding to each antenna pattern is stored.

Here, by setting the weighting amount corresponding to each antenna pattern in the antenna element, the combined directivity (combined pattern) of the entire antenna is obtained, and for example, the pattern shown in FIG. 3 is obtained. Here, in each antenna pattern, the beam direction and the position of the zero point (null point) are set to be different. These weighting amounts are determined in advance by computer simulation or the like.

The following procedure is an operation performed when a user with whom the beam control antenna apparatus of the present invention communicates occurs. For example, when the user A is newly registered as a partner who communicates with the beam control antenna device, the storage device 49 is included in the beam control antenna device of the present invention.
The antenna patterns 1 to 8 stored in
Set the weighting amount.

During this time, the communication with the users other than the user A is temporarily stopped, and the beam control antenna device communicates with only the user A. Here, the transmission line characteristics when the antenna pattern is changed one after another are measured. For example, the user A side transmits, the beam control antenna device side switches the antenna pattern, receives the radio wave from the user A, and measures the reception intensity. FIG. 4 shows an example of the measurement result (relative value of reception intensity) at that time.

In this example, the antenna pattern capable of favorably receiving the radio wave from the user A is the antenna pattern 1 or the antenna pattern 2 (for example, the reception intensity relative value 10).
The above is the level at which good reception is possible), and conversely, the antenna patterns that do not receive radio waves from user A are antenna patterns 3, 6 and 8 (for example, a level at which the reception intensity relative value 3 or less cannot be received). ) Is determined.

Similarly, similar measurements are performed in advance for other users, and a table as shown in FIG. 4 is always prepared on the beam control antenna device side (when the number of users increases or decreases, etc.). Will be updated regularly).

By creating the table as described above, the optimum antenna pattern (weighting vector) can be immediately taken out and set when necessary.
In particular, when the base station and the terminal are spatially fixed as in the case of WLL (Wireless Local Loop), the radio wave propagation environment is temporally fixed. It is very effective as a method of simplifying the control at the time of communication and realizing the optimum transmission path characteristics.

By creating this table, if the antenna pattern used by one user cannot be received by another user, this antenna pattern will not interfere with other users. It can be seen that it is. If this relationship can be realized between two users, the two users will not interfere with each other even if they use the same frequency, and the frequencies can be effectively used.

Explaining in detail using the table of FIG. 4, for example, the user who can share the frequency with the user A is D,
It will be F and G. When user A and user D share the frequency, antenna pattern 1 is used for user A and antenna pattern 3 is used for user D.
The beam control antenna device should be able to communicate by using.

Therefore, in the procedure of (1), the measurement is performed to create the reception strength table for each antenna pattern, (2) the combination of users who can share the frequency is extracted, and (3) the combination of the users The antenna patterns to be used are obtained.

As described above, the combination of users who can share a frequency can be known in advance, which is convenient for allocating the same frequency (same channel) during communication and effectively utilizing frequency resources. In this case, the number of users that can be accommodated in the base station can be increased, and the effect of reducing the cost of the entire system is great.

Finally, the antenna control during communication, which is the procedure of, will be described. Generally, in mobile communication, a communication request is made from a terminal side to a base station using a control channel before communication (call). The beam control antenna device of the present invention can be applied, for example, as a base station device based on such a situation.

It is assumed that the base station (beam control antenna device) side can first grasp how many users have to communicate at the same time by using this control channel. The following operation is performed according to the situation of the user.

(A) When there is only one user communicating at the same time: In this case, the optimum antenna pattern is used for the communicating user. For example, this is the case where the reception strength is maximum, and in the example of FIG.
For the communication, the antenna pattern 1 having the highest reception intensity is used.

(B) When there are a plurality of users communicating at the same time and there is a combination in which frequency sharing is possible: In this case,
Appropriate antenna patterns are used for combinations that can share frequencies. Communication is performed on the same frequency (same channel) for the users who can share the frequency. In the example of FIG. 4, when users A and D make communication requests at the same time, antenna pattern 1 is used for user A and antenna pattern 3 is used for user D.
, The two users communicate on the same frequency.

(C) There are a plurality of users communicating at the same time,
When frequency sharing is impossible: In this case, different frequencies (channels) are given to each user, and an optimum antenna pattern is set for each user. In the example of FIG. 4, when users A and B make communication requests at the same time, there is no combination of antenna patterns that allows frequency sharing between these two users, so each user communicates at a different frequency. Antenna pattern 1 is set for user A, and antenna pattern 2 is set for user B.

As described above, in the present embodiment, the optimum antenna pattern can be set for each user by the control of only extracting and setting the weighting amount stored in the storage device. Therefore, by optimizing the intensity of transmission / reception, the sensitivity of transmission / reception can be improved, and the communication quality can be improved.

Further, since the strength of transmission / reception can be improved, the communication area can be expanded as compared with a normal antenna device. Therefore, when the beam control antenna device of the present invention is used as a base station, there is an advantage that the installation interval of the base stations can be widened and the cost of the entire system can be reduced by reducing the number of base stations. .

Furthermore, the signal processing in this embodiment is very simple, and the beam control can be performed at a higher speed than in the conventional adaptive array antenna or the like.
Therefore, it has a very high utility value for high-speed and large-capacity wireless communication which is expected to be required in the future.

The configuration and control method of the present embodiment can realize an optimum antenna pattern for reception and transmission without the antenna device compensation function (calibration function), and in terms of improvement of characteristics and cost reduction. It is valid. Further, in the present embodiment, the optimum one is selected from a plurality of weighting vector candidates to determine the optimum one according to the actually measured transmission path characteristics, and therefore the value is automatically added even if there is a deviation. The optimum weighting vector is selected. Therefore, an optimum antenna pattern can be set without adding a calibration function.

[0065]

As described in detail above, according to the present invention, a plurality of users can communicate by sharing the same frequency. Therefore, frequency resources can be effectively used. In other words, one base station can allow more users, which leads to equivalent cost reduction.

In particular, in a WLL (Wireless Local Loop) system in which the user is fixed to the base station,
The channel characteristics measured in advance can be used as long as the user distribution does not change, and based on this, user multiplexing (SD
MA: Spatial Division Multiple Access) can be effectively realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a beam control antenna device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of each weighting amount of the antenna pattern in the beam control antenna device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of an antenna pattern in the beam control antenna device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of an antenna pattern and a transmission line characteristic for each user in the beam control antenna device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an operation example in the beam control antenna device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an example of a pattern of a base station antenna according to a conventional method.

FIG. 7 is a diagram showing an example of a pattern of a base station antenna according to a conventional method.

FIG. 8 is a diagram showing a configuration example of a conventional adaptive array antenna.

FIG. 9 is a diagram showing an example of an antenna pattern formed by a conventional adaptive array antenna.

[Explanation of symbols]

11-14 ... Antenna element 71 to 74 ... Antenna element 21-24 ... Switch 31-38 ... Amplifier 41 ~ 48 ・ ・ ・ Frequency converter 51-58 ... Weighting device 75-78 ... Weighter 49 ... Storage device 50 ... Weighting control device 70: Weighting control device 61 ... Distributor 62: synthesizer 79: Synthesizer

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01Q 3/26 H01Q 25/04

Claims (7)

(57) [Claims] 1. A plurality of antenna elements, weighting means for setting a predetermined weighting amount for signals transmitted and received by each of the antenna elements, and a weighting vector configured by each weighting amount set for each of the antenna elements. Storage means for storing a plurality of, a measuring means for measuring the communication channel characteristics in a state in which one of the plurality of weighting vectors is set, a predetermined evaluation from the communication channel characteristics measured by the measuring means A weighting vector for realizing a communication transmission line characteristic based on a criterion, and a selecting means for selecting from the plurality of weighting vectors, and at the time of communication, a weighting amount corresponding to the weighting vector selected by the selecting means is A beam control antenna device characterized by being set to a plurality of antenna elements. 2. A detection means for detecting the reception intensity of the received signal is further provided, and the selection means selects the weighting vector when the reception intensity detected by the detection means becomes maximum. The beam control antenna device according to claim 1, wherein 3. The receiver further comprises a receiving means for receiving the reception intensity of the signal detected by another communication device which has received the transmitted signal, wherein the selecting means is configured to detect the reception intensity of the signal received by the receiving means. The beam control antenna device according to claim 1, wherein the weighting vector when it becomes maximum is selected. 4. A plurality of antenna elements, a weighting means for setting a predetermined weighting amount for a signal transmitted and received by each of the antenna elements, and a weighting vector including each weighting amount set for each of the antenna elements. Among the plurality of weighting vectors, a plurality of weighting vectors are stored between a storage unit that stores a plurality of items, a registration unit that registers another communication device that communicates with the device, and the other communication device that is registered by the registration unit. A measuring means for measuring a communication transmission line characteristic in a state in which one of the two is set, and a weighting vector for realizing a communication transmission line characteristic based on a predetermined evaluation standard from the communication transmission line characteristic measured by the measuring means, Selecting means for selecting from a plurality of weighting vectors, and during communication, the weighting vector selected by the selecting means is added to the weighting vector. Beam control antenna apparatus characterized by setting the weighting factors to respond to the plurality of antenna elements. 5. When a plurality of the communication apparatuses are registered, the selecting unit weights the plurality of weighting vectors so that mutual interference in communication with the plurality of registered communication apparatuses is minimum. The beam control antenna device according to claim 4, wherein a vector is selected. 6. An antenna control method for a beam control antenna device having a plurality of antenna elements, wherein one of a plurality of weighting vectors configured with each weighting amount set for each of the plurality of antenna elements is stored. A first step of selecting, a second step of setting each weighting amount of the plurality of antenna elements by the selected weighting vector, and a communication transmission line characteristic measured in a state of being weighted by the weighting vector. And a fourth step in which the third step is performed a plurality of times based on the plurality of weighting vectors, and a plurality of measured communication channel characteristics are compared, and communication transmission based on a predetermined evaluation criterion is performed. The path characteristics are determined, and the weighting of the antenna element is performed using the weighting vector that realizes the communication transmission path characteristics. Antenna control method for, comprising the fifth step of the constant. 7. An antenna control method for a beam control antenna apparatus having a plurality of antenna elements, wherein one of a plurality of weighting vectors configured with respective weighting amounts set for each of the plurality of antenna elements is stored. A first step of selecting and a second step of registering another communication device that communicates with this device.
And a third step of measuring the communication transmission line characteristic in the state of being weighted by the weighting vector selected in the first step between the other communication device registered in the second step. , The fourth step of performing the third step a plurality of times based on the plurality of weighting vectors, and a plurality of measured communication channel characteristics are compared to determine a communication channel characteristic based on a predetermined evaluation criterion, A fifth step of determining the weighting of the antenna element by the weighting vector that realizes the communication transmission path characteristic.