JP2003218772A - Base station antenna directivity controller in cdma system and base station antenna directivity controller in cdma cellular system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base station antenna directivity controller in a CDMA system, which is capable of exactly calculating optimum transmission weight for a plurality of antenna elements. <P>SOLUTION: An information management section 14 manages arriving direction information and propagation loss information for every user which are outputted by an arriving direction estimating section 13 from each of processing sections 8<SB>1</SB>-8K for every user, and can be estimated with the highest accuracy as a desired wave received at power higher than an interference wave, and at the same time, the section 14 manages transmission rate information for the mobile station of each of users 1-K. A conversion section 15 converts the transmission weight information into transmission power information and outputs it to a transmission weight calculating section 18. The calculated transmission weight is outputted to an AAA transmission section 17, and an output of a coding section 16 is multiplied by the transmission weight and a spreading code for each user's mobile station to form a transmission signal corresponding to each of antenna elements 4a-4d. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CDMA (Code Div) that applies an antenna device having a plurality of antenna elements.
The present invention relates to a base station antenna directivity control device in a CDMA system and a CDMA cellular system used in a cellular mobile radio communication system or the like. In particular, FDD (Frequency Division Duplex) method,
Alternatively, it is suitable for a base station that needs to calculate the transmission weight in a system in which the transmission rates of the uplink and the downlink are different.

[0002]

2. Description of the Related Art W-CDMA is one of the third-generation mobile communication systems, and high-speed and wide-band communication of not only voice but also moving images is expected. Furthermore, recently, studies have begun on the 4th generation mobile communication system aiming at high-speed and wideband transmission, which is about 10 times higher than the 3rd generation system. In order to provide high-speed services with finite frequency resources, it is necessary to make more efficient use of frequencies, and as one of the countermeasures, applying adaptive array antennas (AAA) to base stations has been considered. There is. In the DS-CDMA communication system, many users can communicate at the same time by using different spreading codes even in the same frequency band. But,
Intersymbol interference cannot be ignored as the number of simultaneous communication users increases. Therefore, by applying an adaptive array antenna, a beam pattern that spatially selects only a desired wave and does not select an interference wave is generated, so that communication with less interference signals becomes possible.

FIG. 11 is a block diagram for explaining an example of a base station antenna directivity control device in a conventional CDMA cellular system. In the figure, reference numeral 1 is a base station, which has a cover area (cell) 61. 2 is a mobile station of the user 1 and 3 is a mobile station of the user 2. 4a-4
Reference numeral d denotes a plurality of array antenna elements of the base station 1, which constitutes one array antenna as a whole, and controls the antenna weight (complex number) by which the output signal of each element is multiplied at the time of reception, or to each element at the time of transmission. The beam pattern can be freely controlled by controlling the antenna weight (complex number) to be multiplied by the input signal of.

The direction of the beam pattern will be simplified and described. In the uplink in which the base station 1 receives the transmission wave from each mobile station, the mobile station 2 of the user 1 generates and receives a beam pattern as schematically shown as the user 1 directivity 62. . For the mobile station 3 of the user 2, a beam pattern schematically shown as the user 2 directivity 63 is generated and received. User 1 directivity 62 is
It has a main lobe in the direction of mobile station 2 of user 1 and a beam null in the direction of mobile station 3 of user 2. Similarly, the user 2 directivity 63 has a main lobe in the direction of the mobile station 3 of the user 2 and a beam null in the direction of the mobile station 2 of the user 1.

On the other hand, in the downlink for transmitting the transmission information to each mobile station from the base station 1, the main station has a main lobe in the direction of the mobile station of the user as the transmission partner, and the beam null is in the direction of the mobile station of the other user. The above-described beam patterns of the user 1 directivity 62 and the user 2 directivity 63 are generated and used. However, since the number of beam nulls that can be controlled by the adaptive array antenna is determined by the degree of freedom (the number of elements of the array antenna-1), there is a limitation that the total number of mobile stations other than the transmission partner is within the degree of freedom. However, in the CDMA communication system, normally, simultaneous communication is performed with users who exceed the degree of freedom of the array antenna.

Therefore, even if a beam pattern is generated by an array antenna, the directions of other users and the beam null do not match, interference waves cannot be sufficiently removed, and there is a limit to the number of users that can be accommodated. However, there was a limit to the improvement of frequency utilization efficiency. In particular, in the downlink transmitted from the base station 1 to each mobile station, the transmission beam pattern is generated in a situation where the direction and magnitude of the incoming wave at the mobile station are unknown, so the accuracy of calculating the antenna weight deteriorates. It's easy to do. Therefore, it is difficult to determine the antenna weight that optimizes the interference characteristics of each downlink mobile station.

As a method of relatively easily determining the optimum antenna weight in the downlink, (1) the antenna weight obtained in the uplink is used as it is or is calibrated to determine the antenna weight of the downlink. There is a way to do it. Also, (2) there is a method of estimating the incoming wave from each mobile station from the received signal obtained on the uplink and determining the downlink antenna weight based on that information (Kitahara).
Others, “Adaptive array antenna for W-CDMA downlink”
2001 Sogaku Sozen, B-5-15, Kitahara et al., "A Study on Path Selection for Adaptive Array Antenna for W-CDMA Downlink"
See SI Tech Report, AP 2001-117 (2001).

In the above method (1), an error occurs in the optimum antenna weight as the carrier frequency difference between the uplink and the downlink increases. In addition, when performing multi-rate service, there is no correlation between the transmission powers of the uplink and the downlink when the transmission rates are asymmetric between the uplink and the downlink, so the downlink base station reception characteristics and the uplink Symmetry with the mobile station reception characteristics of is not established. As a result, the optimum antenna weight obtained in the uplink is not the optimum antenna weight in the downlink, so the application effect of the adaptive array antenna becomes small.

On the other hand, the above-mentioned method (2) estimates the received power of each mobile station in the downlink by using the propagation loss estimated using the uplink. However, the transmission power of the downlink differs depending on the transmission rate of the downlink of each mobile station. Next, the optimum weight is calculated using the received power of each mobile station on the downlink and the estimated arrival direction. This method, even if the symmetry of the reception characteristics does not hold, such as the transmission rate is different in the uplink and downlink,
A relatively good optimum antenna weight can be obtained.

FIG. 12 is a block diagram showing an example of a base station in the conventional CDMA cellular system. The downlink antenna weight is determined from the information obtained by estimating the arrival direction and the propagation loss of each mobile station from the received signal obtained on the uplink. Portions corresponding to those in FIG. 11 are designated by the same reference numerals. 5a to 5d are duplexers, 6a to 6
d is an RF receiver. All are provided for each of the array antenna elements 4a to 4d, and the subscripts correspond to the subscripts of the array antenna elements 4a to 4d. The number of elements may be arbitrary as long as it is plural. The duplexers 5a to 5d are
The antennas are inserted so that the antennas can be used for both transmission and reception, and the outputs of the array antenna elements 4a to 4d are R
It is supplied to the F reception units 6a to 6d. RF receivers 6a to 6d
Amplifies, frequency converts, and digitally demodulates A /
D-convert and output.

Reference numeral 7 is a distributor, and 8 ₁ to 8 _K are user-specific processing units. The same configuration is provided for each user, and the subscripts indicate user numbers 1 to K. The distributor 7 includes RF receiving units 6a to 6d.
Each output of the above is distributed to each of the processing units 8 ₁ to 8 _K for each user. The user-specific processing units 8 ₁ to 8 _K are all RF reception units 6 a corresponding to the array antenna elements 4 a to 4 d.
6d is input, the despreading process and the reception weight multiplication using the spreading code of each user 1 to K are performed in the AAA receiving unit 11 described later, and each user 1 to K is decoded in the decoding unit 12 described later. Output the restored data of.

Further, the transmission data of each of the users 1 to K is input, and the encoding unit 16 described later performs error correction encoding,
A transmission weight multiplication and a spreading process using a spreading code for the user for each system are performed on the signals distributed to a plurality of systems in an AAA transmission unit 17, which will be described later, and transmission signals of a plurality of systems corresponding to array antenna elements 4a to 4d are obtained. It is generated and output to the synthesizer 9. The combiner 9 adds and combines the transmission signals output from the user-specific processing units 8 ₁ to 8 _{K for} each system of the array antenna elements 4a to 4d, and outputs the combined signals to the RF transmission units 10a to 10d. The RF transmitters 10a to 10d perform frequency conversion and amplification, and supply and transmit the array antenna elements 4a to 4d via the duplexers 5a to 5d.

The processing for each user will be described by targeting the processing unit for each user 8 ₁ . In the AAA (adaptive array antenna) receiving section 11, the reception outputs of the array antenna elements 4a to 4d are multiplied by the spreading code for the user 1 to perform despreading, and then weighted and combined with the antenna weight. If necessary, perform fading fluctuation estimation, RAKE combining, de-interleaving,
Output to the decoding unit 12. The decoding unit 12 performs decoding for error correction and restores the transmitted data. Also, the AAA receiving unit 11 performs the DOA estimation, and outputs the information of the result to the transmission weight calculating unit 18.

On the other hand, the transmission data is error-correction-encoded in the encoding unit 16 and distributed and output to a plurality of systems in the AAA transmission unit 17, where the transmission weights are weighted to the array antenna elements 4a to 4d. Be seen. The transmission weight calculation unit 18 calculates the transmission weight based on the arrival direction estimation result information and outputs it to a multiplier (not shown) provided in each system, and each output of the multiplier is input to the spreading unit, Each spreading section multiplies the spreading code of user 1 and outputs the transmission signal of user 1. The AAA receiving unit 11 may perform despreading after multiplying the reception weights. In addition, the AAA transmission unit 1
In 7, the transmission weight may be multiplied after spreading the error correction code.

FIG. 13 is a block diagram for schematically explaining the weight calculation of the conventional adaptive array antenna using the DOA estimation. The weight calculation in the user-specific processing unit 8 ₁ in FIG. 12 will be described as an example. Illustration of the despreading part, the diffusing part, etc. is omitted. In the figure, reference numeral 81 is a reception weight calculation unit, which is provided in the AAA reception unit 11 of FIG. 82a to 82d are multipliers,
To receive the output of the array antenna elements 4 a to 4 d, respectively, by multiplying the reception weight w ₁ to w _4, by combining the multiplication results in the adder 83, and outputs to the decoding section 12 of FIG. 12, the reception weight calculation unit It also outputs to 18.

In the reception weight calculator 81, the well-known minimum square error method (MMSE: Minimum Mean Square Error) is used.
Calculate the antenna weight by MMSE control
Although the optimum solution of the reception weight is given, in consideration of the control follow-up in the actual environment, other control such as steering beam which directs only the main beam direction to the desired wave direction has been proposed. At the same time, the well-known MUSIC (MUltiple SIgnal Classif
ication) and ESPRIT (Estimation of SignalParameters
via Rotational Invariance Techniques), or
All users by beamformer method etc.
The arrival wave of the received wave from i (i = 1 to K) is estimated.

The arriving waves estimation results, the estimated arrival direction information of the received wave from the mobile station i users i 'and _i, the arrival direction theta' theta received power _i by measuring, the measurements The received power information is Pr ′ _i . Based on this received power information, the base station 1 can estimate the propagation loss from the mobile station to the base station 1. The easiest way to do that is
Propagation loss can be obtained by setting and storing the reference transmission power of the transmission power of the mobile station in advance and dividing the reference transmission power by the reception power. In the following description, the propagation loss information L ′ _i will be used. Therefore, for the received waves from the mobile stations 1 to K of all users, all the arrival direction information θ ′ ₁ , θ ′ ₂ , ... θ ′ _K and all the propagation loss information L ′ ₁ and L ′. ₂ , ..., L' _K are estimated.

The transmission weight calculation is shown in FIGS.
Let's take a closer look and give a brief touch here. The transmission weight calculation unit 18 generates an array propagation vector (array direction vector) determined by the estimated signal arrival direction of the mobile station of the i-th user, the downlink frequency, and the array shape. Also,
An estimated value of user reception power is obtained based on the transmission power of the base station for the mobile station of the i-th user and the above-mentioned propagation loss information.

According to the method of the paper described in (2) above, a correlation matrix is generated using the above-mentioned array direction vector and the estimated value of user received power, and this correlation matrix and the mobile station of the user who is the transmission partner. The transmit antenna weight is determined by using the array direction vector for. The transmission weight calculator 18 calculates the transmission weights w ₁ ^{(1) to} w ₄ ⁽¹⁾ of the user 1 for the mobile station 2, and the multipliers 71 a to 71
output to d. The multipliers 71a to 71d multiply the outputs of the encoder 16 shown in FIG. 12 by the respective transmission weights w ₁ ^{(1) to} w ₄ ⁽¹⁾ , and the corresponding array antennas 4a to 4d. The transmission signal is output to.

In the above description, the user-specific processing unit 8 ₁ has been described. The base station 1 also performs the same process for each of the users 1 to K. Therefore, the transmission weight calculation is as shown in FIG. 14 for the entire base station 1. 14
FIG. 13 is an explanatory diagram of transmission weight calculation in all the user-specific processing units 8 ₁ to 8 _K in FIG. 12. In this figure, user 1
And only the transmission weights of user 2 for the two mobile stations are shown. Reference numeral 21 denotes the RF transmitters 6a to 6a shown in FIG.
6d is displayed together in one block. The distributor 7 is not shown in the drawing, and the distribution is shown by the branch of the connection. AAA receiver 11 and transmission weight calculator 1
The suffixes 8 indicate users 1 and 2, respectively.

All the arrival direction information and all the propagation loss information in the processing units 8 ₁ to 8 _K for each user are θ ′ ₁ , θ ′ ₂ , ... θ ′ as described with reference to FIG. _K , L' ₁ ,
It was L' ₂ , ..., L' _K . User 2's AAA receiver 1
By performing the same calculation for 1, the total DOA estimation value and total propagation loss estimation value θ " ₁ , θ" ₂ , ..., θ " _K ,
L " ₁ , L" ₂ , ..., L " _K are obtained. The transmission weight calculation unit 18 ₁ of the user ₁ and the transmission weight calculation unit 18 ₂ of the user 2 calculate the user based on these estimated values. Antenna weight vectors w ⁽¹⁾ and w ⁽²⁾ for the mobile stations ¹ and ² are calculated.

However, the above calculation is performed for a single isolated cell. When introducing an adaptive array antenna into a real cellular system,
If the weight of the array antenna is calculated by ignoring the influence of the mobile stations in the neighboring cells, the application effect of the adaptive array antenna becomes small. It is necessary to evaluate the control method of the adaptive array antenna including the surrounding cells. In addition, similar arrival wave estimation is repeated in each of the user-specific processing units 8 ₁ to 8 _K. In addition, the processing unit 8 for each user
_{At 1} to 8 _K , the estimation accuracy does not deteriorate because the desired wave is certainly received with higher power than the interference wave. Deteriorated.

[0023]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and improves the accuracy of estimation of the direction of arrival of interference waves, and considers the influence of interference waves from neighboring cells. , It is possible to accurately calculate the optimum transmission weights for a plurality of antenna elements.
Base station antenna directivity control device and CD
An object of the present invention is to provide a base station antenna directivity control device in the MA cellular system. Also, by considering the degree of the influence of the interference wave on the distance, the base station antenna directivity control device in the CDMA system and the base station antenna directivity in the CDMA cellular system capable of accurately calculating the optimum transmission weights for a plurality of antenna elements. An object is to provide a control device.

[0024]

According to a first aspect of the present invention, a CDMA for performing communication with a plurality of user communication devices using an antenna device having a plurality of antenna elements. A base station antenna directivity control apparatus according to the above method, wherein a desired wave received from each user communication apparatus is estimated based on received signals of a plurality of systems received by the plurality of antenna elements, and each user communication apparatus Desired wave estimating means for outputting incoming wave information regarding the user communication apparatus, information managing means for managing the incoming wave information regarding each of the user communication apparatuses, and transmission power information of a signal to be transmitted to each of the user communication apparatuses; By using the information about each user communication device, the directivity gain to the user communication device as a transmission partner is large, and the directivity gain to the other user communication devices is large. To produce a beam pattern such that fence, said antenna weights for each antenna element, and has an antenna weight output means for outputting the calculated for each of the transmission destination to become a user communication device. Therefore, the arrival wave information related to the other user communication device that is not the transmission partner is output by estimating the desired wave received from the other user communication device, so that the estimation accuracy of the interference wave is improved. As a result, the effect of reducing the amount of interference, which is superior to that of the conventional method, can be realized and the frequency utilization rate is improved. Moreover, since it is not necessary to estimate all the incoming waves for each user communication device, the process of the base station antenna directivity control device in the CDMA system is simplified. In addition,
The arrival wave information usually includes arrival direction information and propagation loss information.

In a second aspect of the present invention, in the base station antenna directivity control device in the CDMA system according to the first aspect, the desired wave estimating means estimates only the arrival direction of the desired wave, Only the arrival direction information is output as the arrival wave information regarding each user communication device. Therefore, it is not necessary to estimate or measure the received power information. Although it becomes impossible to obtain the propagation loss information from the desired wave estimating means, the information managing section may manage the propagation path loss information estimated by another method. Alternatively, the antenna weight output means can perform weight calculation without using the propagation loss information. When operating an antenna device having a plurality of antenna elements, the phase information (arrival direction) is dominant over the amplitude information, and thus only the phase information (arrival direction) may be used.

In a third aspect of the present invention, in the base station antenna directivity control device in the CDMA system according to the first or second aspect, the arrival of the user communication device as the communication partner from the information managing means. In addition to selecting the wave information and the transmission power information, it has information selection means for narrowing down the incoming wave information and the transmission power information related to the other user communication device and outputting them to the antenna weight output means. Is. Therefore, since the number of interference waves to be considered when calculating the transmission weight is reduced, the beam pattern can be generated by effectively utilizing the degree of freedom of the antenna device. As a result, the effect of reducing the amount of interference, which is superior to that of the conventional method, can be realized, and the frequency utilization rate is improved. In particular, in an environment where an interference wave exceeding the degree of freedom of the array antenna exists, it is possible to freely select the interference wave and reduce the interference.

In the invention according to claim 4, in the base station antenna directivity control device in the CDMA system according to claim 3, the information selecting means is provided with respect to arrival wave information of the other user communication device. The number of the arrival wave information is reduced by combining those having close arrival angles, the transmission power information is combined in accordance with the combined arrival wave information, and the combined arrival wave information is The arrival direction information and the combined transmission power information are output to the antenna weight output means as information regarding the other user communication device. Therefore, it is possible to easily reduce the number of interference waves to be considered when calculating the transmission weight, and it is possible to minimize the influence of the reduction. In addition, a predetermined number of pieces of information regarding other user communication devices are selected in order from the one having the highest transmission power, and a beam pattern is generated so that the directivity gain for the other user communication devices having the predetermined number of high transmission power becomes small. Or vice versa,
A predetermined number of pieces of information about other user communication devices are selected in order from the one with the lowest transmission power, and a beam pattern is generated so that the directivity gain for the other user communication devices with the predetermined number of low transmission powers becomes small. You can

In a fifth aspect of the present invention, in the base station antenna directivity control apparatus in the CDMA system according to any one of the first to fourth aspects, a plurality of systems received by the plurality of antenna elements are used. The receiving means outputs the reception information by calculating the reception weight for each antenna element for each user communication device that is a reception partner based on the reception signal of, and the desired wave estimating means is The desired wave received from each of the user communication devices is estimated by using the intermediate calculation result. Therefore, since the intermediate calculation result of the receiving means can be used for estimating the incoming wave received from the user communication device of the own cell, the processing amount of the base station device as a whole is reduced.

In a sixth aspect of the invention, a CDM for performing communication with a plurality of user communication devices in its own cell using an antenna device having a plurality of antenna elements.
A base station antenna directivity control apparatus in the A cellular system, wherein a desired wave received from each user communication apparatus of the own cell is received based on received signals of a plurality of systems received by the plurality of antenna elements of the own cell. A desired wave estimating unit that estimates and outputs incoming wave information regarding each user communication device of the own cell, and each of the neighboring cells based on a plurality of systems of received signals received by a plurality of antenna elements of the own cell A neighboring cell arrival wave estimating means for estimating an arrival wave received from the user communication device and outputting arrival wave information regarding each user communication device in the peripheral cell, and arrival wave information regarding each user communication device in the own cell and the Transmission power information of a signal transmitted to each user communication device of its own cell, arrival wave information about each user communication device of the peripheral cell, and base station of the peripheral cell Information management means for managing transmission power information of a transmission signal transmitted to each user communication device of the peripheral cell, information on each user communication device of the own cell that is managed, and each user of the managed peripheral cell Using the information about the communication device, the directivity gain of the own cell, which is a transmission partner, to the user communication device is large, and the directivity gain of the other user communication device of the own cell and the user communication devices of the neighboring cells is small. In order to generate such a beam pattern, the antenna weight output means calculates and outputs the antenna weight for each antenna element of the own cell for each user communication device of the own cell that is the transmission partner. . Therefore, since the arrival wave information regarding the other user communication device of the own cell which is not the transmission partner is output by estimating the desired wave received from the other user communication device, the estimation accuracy of the interference wave is improved. . Further, since the incoming wave information regarding the user communication device of the peripheral cell is managed, the transmission weight can be calculated in consideration of the influence on the peripheral cell. As a result, the effect of reducing the amount of interference that is superior to the conventional method can be realized,
The frequency utilization rate is improved. In particular, in an environment in which an interference wave exceeding the degree of freedom of the array antenna exists, antenna weight calculation that can reduce the interference wave most can be performed. As a method of estimating the arrival wave received from each user communication device in the peripheral cell, for example, there is a method of estimating from the antenna reception signal of the own cell using a known arrival direction estimation means. On the other hand, the transmission power information of the transmission signal that the base station of the peripheral cell transmits to each user communication device of the peripheral cell is estimated from the information such as the reception power or the cell radius, or is transmitted to a predetermined mobile station. Use the reference transmission power. In some cases, the transmission power information described above can be collected from the base stations of the peripheral cells, including the position information of each user communication device in the peripheral cells. Regarding the user communication device of the peripheral cell, if the arrival wave information and the transmission power information do not match, also in the above-mentioned arrival wave information,
It is not necessary to identify which neighboring cell is from which mobile station. In this case, as the transmission power, the above-mentioned predetermined reference transmission power to the mobile station is used.

In a seventh aspect of the present invention, in the base station antenna directivity control device in the CDMA cellular system according to the sixth aspect, the desired wave estimating means estimates only the arrival direction of the desired wave. , Only the arrival direction information is output as the arrival wave information regarding each of the user communication devices, and the neighboring cell arrival wave estimation means estimates only the arrival direction of the arrival wave, and each user communication of the neighboring cell is performed. Since only the arrival direction information is output as the arrival wave information regarding the device, the same operation as the invention according to claim 2 is achieved.

According to an eighth aspect of the present invention, in the base station antenna directivity control apparatus in the CDMA cellular system according to the sixth or seventh aspect, the information managing means causes the user communication of the own cell which is the transmission partner. While selecting the incoming wave information regarding the device and the transmission power information, narrowing down the incoming wave information and the transmission power information regarding other user communication devices of the own cell and user communication devices of the neighboring cells Then, it has an information selecting means for outputting to the antenna weight outputting means. Therefore, the same effect as the invention according to claim 3 is achieved.

In a ninth aspect of the present invention, in the base station antenna directivity control apparatus in the CDMA cellular system according to the eighth aspect, the information selecting means is another user communication apparatus of the own cell and the periphery. Regarding the arriving wave information from the user communication device of the cell, while reducing the number of the arriving wave information by synthesizing those having close arriving angles, the transmission power information according to the synthesized arriving wave information. And outputs the direction-of-arrival information regarding the combined arrival-wave information and the combined transmission power information as information regarding other user communication devices of the own cell and user communication devices of neighboring cells. To do. Therefore, it is possible to easily reduce the number of interference waves to be considered when calculating the transmission weight, and it is possible to minimize the influence of the reduction. In addition, a predetermined number of pieces of information regarding other user communication devices of the own cell and user communication devices of neighboring cells are selected in order from the one having the highest transmission power, and the directivity for the predetermined number of other user communication devices having high transmission power is selected. A beam pattern that reduces the gain is generated, or conversely, a predetermined number of pieces of information regarding other user communication devices of the own cell and user communication devices of neighboring cells are selected in order from the one having the lowest transmission power. It is also possible to generate a beam pattern in which the directivity gain for a predetermined number of low-transmission-power other-user communication devices is small.

In a tenth aspect of the present invention, in the base station antenna directivity control device in the CDMA cellular system according to any one of the sixth to ninth aspects, reception is performed by a plurality of antenna elements of the own cell. The desired wave estimating means includes a receiving means for outputting reception information by calculating a reception weight for each antenna element for each user communication device of its own cell which is a reception partner on the basis of the received signals of the plurality of systems. Is for estimating the desired wave received from each of the user communication devices by using the intermediate calculation result in the receiving means. Therefore, the same effect as the invention according to claim 5 is achieved.

According to the eleventh aspect of the present invention, there is provided a base station antenna directivity control device in a CDMA system for communicating with a plurality of user communication devices by using an antenna device having a plurality of antenna elements. , Direction-of-arrival information about each of the user communication devices, propagation loss information, transmission power information, and using a weighting function for reducing interference to each of the user communication devices far from the base station The antenna weight for each of the antenna elements becomes the transmission partner so as to generate a beam pattern in which the directional gain to the user communication device is large and the directional gain to the other user transmission device is small. It is calculated and output for each user communication device. Therefore, by using the weighting function described above, it is possible to generate the antenna directivity pattern in consideration of the influence of distance. As a result, the effect of reducing the amount of interference, which is superior to that of the conventional method, can be realized, and the frequency utilization rate is improved. Any method may be used as the method of estimating the incoming wave received from each user communication device.

According to a twelfth aspect of the present invention, in the base station antenna directivity control device according to the ninth aspect,
The base station antenna directivity control device in the CDMA system according to claim 11, wherein the transmission power for each user communication device is multiplied by the weighting function, and a value considering propagation loss is assumed to be the reception power of each user communication device. The value is regarded as a value, a correlation matrix relating to the received signal of each user communication device is generated, and the antenna weight for each antenna element is calculated for each user communication device as the transmission partner. Therefore, it is possible to easily realize the antenna directivity pattern considering the influence of the distance.

In the thirteenth aspect of the invention, the base station antenna directivity control in the CDMA cellular system for performing communication with a plurality of user communication devices of its own cell by using an antenna device having a plurality of antenna elements. The device, the arrival direction information about each user communication device of the own cell, the propagation loss information, the transmission power information, the arrival direction information about each user communication device of the peripheral cell, propagation loss information,
Transmission power information on the transmission power transmitted by the base station of the neighboring cell to each user communication device of the neighboring cell, and a distance from the base station of the own cell is far, and each user communication device of the own cell and the neighborhood Using a weighting function for reducing the interference of the cell with each user communication device, the directivity gain to the user communication device of the own cell as a transmission partner is large, and the other user communication device of the own cell and the The antenna weight for each antenna element is calculated and output for each user communication device of the own cell that is the transmission partner so as to generate a beam pattern that reduces the directivity gain of the peripheral cell to the user communication device. It is a thing. Therefore, since the arrival wave information about the user communication device in the neighboring cell, the propagation loss information, and the transmission power information about the transmission power that the base station of the neighboring cell transmits to each user communication device in the neighboring cell are obtained, the influence is exerted on the neighboring cell. The transmission weight can be calculated in consideration of the influence. Further, by using the weighting function, it is possible to form the antenna directivity pattern in consideration of the influence of distance. In particular, the interference given to the user communication devices in the peripheral cells is reduced. As a result, the effect of reducing the amount of interference, which is superior to that of the conventional method, can be realized, and the frequency utilization rate is improved. The arrival direction information regarding each user communication device in the peripheral cell, the transmission power information transmitted to each user communication device in the peripheral cell, can be obtained by any method as described in the invention according to claim 6. Good.

In a fourteenth aspect of the present invention, in the base station antenna directivity control device in the CDMA cellular system according to the thirteenth aspect, the transmission power for each user communication device of the own cell is multiplied by the weighting function. , A value considering the propagation loss is regarded as a reception power assumed value of each user communication device of the own cell, and the weighting function is applied to the transmission power from the base station of the peripheral cell for each user communication device of the peripheral cell. Multiply, a value considering the propagation loss is regarded as a reception power assumed value of each user communication device of the peripheral cell to generate a correlation matrix relating to the received signal of each user communication device, and an antenna weight for each antenna element, It is calculated and output for each user communication device that is the transmission partner. Therefore, it is possible to easily realize the antenna directivity pattern considering the influence of the distance.

1 is a block diagram of a CDMA cellular system of the present invention.
Of a base station antenna directivity control device in
3 is a block configuration diagram for explaining an embodiment of FIG.
In the figure, the same parts as those of the conventional FIG.
The description is omitted. Reference numeral 13 is a desired wave estimation unit, which is shown in FIG.
In the above, what was included in the AAA receiving unit 11
It is explicit. However, in the conventional configuration, as shown in FIG.
3, as shown in FIG. 14, the processing unit 8 for each user ₁~ 8_KTo
Therefore, the DOA estimations of all users in the same cell are duplicated.
I was going. On the other hand, in this embodiment, the
The processing unit 8₁~ 8_KEach of each user
Estimate only the desired wave from the signal received from the mobile station. example
For example, the processing unit 8 for each user₁, The direction of arrival information θ₁Oh
And propagation loss information L₁Only for transmission weight calculation
To estimate.

Since the arrival wave estimation may partially perform the same processing as the reception weight calculation processing, in that case, the processing can be shared. As a result, the arrival wave estimation unit 1
In 3, the configuration of the desired wave estimation itself becomes simple. Alternatively, in the figure, as indicated by an arrow indicated by a broken line, the AAA receiving unit 1
1 or pass through the AAA receiving unit 11 without passing it, and output the output of the distributor 7, that is, the received outputs of the array antenna elements 4a to 4d to the desired wave estimating unit 13, where All the processes for the DOA estimation may be performed only on the desired wave transmitted from the mobile station of the user.

The information management unit 14 includes a processing unit 8 _{1 for} each user.
The arrival direction information θ ₁ , θ ₂ , ... θ _K and the propagation loss information L ₁ , which are output by the arrival direction estimation unit 13 of each user of ˜8 _K ,
L _2, ......, manage L _K, at the same time, component (not shown) of the base station 1 is held as information on a base station transmission, transmission rate information Ps _i for the mobile station for each user 1~K
Manage and list these. Information management unit 14
In this way, since the arrival direction information and the propagation loss information regarding the communication device of each user are centrally managed, it is possible to generate the optimum beam pattern by using these information. For example, in the case of DS-CDMA, it is necessary to increase the transmission power as the transmission rate increases. If the same modulation method is used, transmission power proportional to the transmission rate is required.

Reference numeral 15 is a conversion unit, which is the transmission rate information Ps.
Converting _i into transmission power information T _i (relative transmission power),
It is output to the transmission weight calculator 18. The arrival direction information θ _i and the propagation loss information L _i are output as they are. Note that the information management unit 14 may manage information on the number of transmission channels instead of the transmission rate information Ps _i . The number of transmission channels and the transmission rate information usually have a correspondence relationship.
Alternatively, if the transmission power information T _i is managed, the conversion unit 15 becomes unnecessary. The transmission weight calculator 18 calculates the transmission weight and outputs it to the AAA transmitter 17.

FIG. 2 shows all user-specific processing units 8 _{1 of} FIG.
It is explanatory drawing which shows the weight calculation of the array antenna in 8 _K. In the figure, the AAA receiving unit 11 and the transmission weight calculating unit 18 are attached with subscripts indicating users. The AAA receiving unit 11 includes the desired wave estimating unit 13 of FIG. In addition, the desired wave estimation unit 13 may directly obtain the reception signal of the array antenna element from the distributor 11. Reference numeral 22 denotes an information management unit, which is a combination of the information management unit 14 and the conversion unit 15 shown in FIG.

The transmission weight calculators 18 ₁ to 18 _{1 for the} respective users
Direction of arrival information and propagation loss information input to 8 _K are
At first glance, it seems that the same information as that of the related art shown in FIG. 12 is input, but in the embodiment of the present invention, the arrival direction information θ _i and the propagation loss information L _i are each input rather than the interference wave. to obtain what was most accurately estimated as the desired wave received by the reliably higher power from the user-specific processing sections 8 ₁ to 8 _K. As a result, the accuracy of transmission weight calculation is improved.

Here, a method for calculating the transmission weights w ^{(1) to} w ^(K) for each user's mobile station will be described. Basically, the calculation method described in the prior art is used. Using the uplink signal, the base station 1 estimates the radio wave arrival direction θ _i from each mobile station and the propagation loss L _i .
Any method may be used as the radio wave arrival direction estimation method. For example, a known method such as MUSIC or ESPRIT may be used. Any method may be used as the propagation path loss estimation method.

FIG. 3 shows the first embodiment of the present invention.
FIG. 3 is a conceptual diagram of an example of propagation loss estimation used for
It Figure 3 (a) shows the transmission power of the base station and the reception power of the mobile station.
The relationship between force and propagation loss, FIG.
Of the transmission power and the reception power at the base station, and the propagation loss
It shows the relationship of. In FIG. 3A, propagation
Loss L_iIs the transmission power T of the mobile station of user i at base station 1. _miTo
If you know, from the received power, use the following relational expression
It can be easily estimated.

[Equation 1] As shown in FIG. 3B, the transmission power from the base station 1
The same propagation loss L _i is obtained when the mobile station receives at reception power P _mi when transmitting at T _i .

An array propagation vector (array direction vector) determined by the estimated signal arrival direction of the mobile station of the user i, the downlink frequency, and the array shape is represented by v _i (For the array propagation vector, Kikuma, “By array antenna) Adaptive signal processing ”, Science and Technology Publishing (1998) p.30
―31). P _i is the “value assumed as the i-th user power”, f _i is the weighting function of the i-th user of the own cell, and P n
Is the thermal noise power, the correlation matrix R _xx for weight calculation is

[Equation 2] It is defined as Here, the antenna weight w _{k of} which the mobile station of the user k is the transmission partner is

[Equation 3] And give. R _xx ^-1 represents the inverse matrix of R _xx .

As the above-mentioned "value assumed as the i-th user power" P _i , a value dependent on parameters such as transmission power and propagation loss of the base station 1 for the mobile station of the user i is used. That is, P _mi (= T _i / L _i ) shown in FIG.
As may be substituting the estimated desired received power at the time of a transmission partner mobile station of the user i in the own cell from the base station, as T _i that shown in FIG. 3 (b) of the base The value of the desired wave transmission power with the mobile station of the user i in the own cell as the transmission partner may be substituted from the station 1. Therefore, the above equation (1)
The L _i obtained from is not necessarily required. Generally, when the k-th mobile station is the desired wave mobile station, the directivity in the i-th user direction (that is, θ _i ) is increased by increasing the value of P _i with respect to the other mobile stations. A null can be intentionally provided.

On the other hand, f _i is a weighting function, and a simple example will be shown here, although the details will be described later. Interpreting the reference (2) cited in the description of the prior art, when R _xx is calculated using the array response vector and power of all users 1 to K, when f _i = 1 for all users Corresponding to. Further, when R _xx is calculated using the array response vector and power of only the user who becomes high speed in the downlink, f _i = 1 for the high speed user and f _i = 0 for the low speed user. It corresponds when set.

FIG. 4 is a block diagram for explaining the second embodiment of the present invention. 12, those parts that are the same as those corresponding parts in FIGS. 12 and 1 are designated by the same reference numerals, and a description thereof will be omitted.
In this embodiment, the transmission weight is determined in consideration of the interference of the users in the neighboring cells with the mobile station. Reference numeral 31 denotes an incoming wave estimation unit from mobile stations in neighboring cells, and 32
Is an information management unit. It is possible to arbitrarily determine how far the mobile stations in the neighboring cells are from the own cell. It is also possible to determine the range of mobile stations to be collected in cell units, or to set the range of neighboring cells from the base station of the own cell to the mobile station located at a predetermined distance.

Arrival wave estimation unit 31 from mobile stations in neighboring cells
In (1), regarding the arrival wave from the mobile station located in the peripheral cell, the arrival direction is estimated and the received power is measured.
The arrival direction estimation value is used as the arrival direction information, and the propagation loss information is obtained from the received power. As a method of estimating the arrival wave received from each user communication device in the peripheral cell, for example, there is a method of using known arrival direction estimation means such as MUSIC or ESPRIT from the antenna reception signal of the own cell.

FIG. 5 shows an example of arriving waves from mobile stations in neighboring cells being extracted from a plurality of estimated arriving directions in the arriving wave estimating section 31 from mobile stations in neighboring cells shown in FIG. FIG. In the figure, the horizontal axis represents the arrival angle θ of the incoming wave, and the vertical axis represents the received power Pr of the incoming wave. For example, the beam former method is used to estimate all the arrival directions θ by scanning the main beam and measure the power Pr in the arrival directions θ. From among them, the components of the received powers Pr ₁ , Pr ₂ , ..., Pr _K of the desired waves obtained in the AAA receiving unit 11 _{1 of the} user ₁ to the AAA receiving unit 11 _K of the user K (arrival direction information θ ₁ , Θ ₂ , ..., θ _K , the components of the components (arrows indicated by broken lines in the figure) other than the components indicated by the solid lines in the figure are estimated to be arriving waves from mobile stations in neighboring cells.

Alternatively, the arrival wave can be more accurately estimated by canceling the signal from the user in the own cell and then using the known arrival direction estimation such as MUSIC and ESPRIT. That is, the received powers Pr ₁ , Pr ₂ , ..., P
Based on the components of r _K (arrival direction information θ ₁ , θ ₂ , ..., θ _K ) and the restored data of the user of the own cell, the desired waves (reception power Pr ₁ , Pr ₂ ,. _K , direction of arrival information θ ₁ ,
θ _2, ......, θ _K) is, in the RF receiver 21 (FIG. 1, RF
A replica of the received signal output from the receiving units 6a to 6d) is generated. Next, regarding the signals obtained by subtracting the replicas from the outputs of the RF receivers 6a to 6d, MUSIC, ESPRIT
It is also possible to perform known direction of arrival estimation such as, for example, Kitahara et al. "Adaptive array antenna for downlink of DS-CDMA system in multi-user environment" RCS99-21
6 (2000))

Referring to FIG. 5, the components of the received power Pr ₁ , Pr ₂ , ..., Pr _K of each desired wave shown in the figure (arrival direction information θ ₁ , θ ₂ , ..., θ _K , FIG. (Middle, arrow shown by solid line)
This means that the arrival wave estimation is performed again for the power from which the power of has been removed. That is, since the incoming wave estimation is performed for the mobile station of the own cell user from which the incoming waves have been removed, the total number of incoming waves that need to be estimated is reduced, and therefore the accuracy of the incoming wave information estimation by the array antenna is reduced. improves.

Arrival wave estimation unit 31 from mobile stations in peripheral cells
Is the arrival direction information θ ^Δ as an arrival wave estimation result from a mobile station in a peripheral cell (a mobile station from user 1 to user M. It is not necessary to distinguish which peripheral cell is the mobile station). ₁ , θ ^Δ ₂ , ..., θ ^Δ _M , received power information Pr ^Δ ₁ , P
Outputs r ^Δ ₂ , ..., Pr ^Δ _M to the information management unit 32. At that time, in the illustrated example, the received power information Pr ^Δ ₁ , Pr ^Δ ₂ , ...
, Pr ^Δ _M are replaced with the propagation loss information L ^Δ ₁ , L ^Δ ₂ , ..., L ^Δ _M for management. The information management unit 32 also manages transmission rate (number of transmission channels) information for mobile stations (user 1 to user M) in neighboring cells. This transmission rate is the downlink transmission rate from the base station of the cell in which this mobile station is located. This transmission rate (number of transmission channels) information may be converted into transmission power information T ^Δ ₁ , T ^Δ ₂ , ..., T ^Δ _M for information management, or may be converted into transmission power information after information management. May be.

The transmission power information of the transmission signal transmitted from the base station of the peripheral cell to each user communication device of the peripheral cell is estimated from the information such as the reception power and the cell radius at the base station 1 of the own cell, or in advance. The reference transmission power value of the defined mobile station is managed. When the transmission power information does not specify which mobile station in which neighboring cell transmitted the reference transmission power value, the arrival wave information and the arrival wave information regarding the user communication device in the neighboring cell Since it cannot be associated with transmission power information, MUSIC, E
Even when using known direction of arrival estimation such as SPRIT, it is not necessary to specify which mobile station is in which neighboring cell from which mobile station, and it is understood that there is an incoming wave of a certain received power from a certain incoming direction. Good.

Further, the base station 1 is provided with a function of collecting the transmission rate information (the number of channels) or the transmission power information of the transmission signal transmitted from the base station of the peripheral cell to each user communication device of the peripheral cell. When the arrival wave is estimated, the arrival wave from which mobile station in which neighboring cell is specified is identified by some method, and the correspondence between the arrival wave information and the transmission power information of the transmission signal described above is provided. You should be able to attach. At the time of estimating the incoming wave, in order to identify the incoming wave from which mobile station in which neighboring cell, from the base station of the neighboring cell, for example, each user communication device of the neighboring cell is used for transmission. It suffices to obtain the spread code or the position information of each user communication device in the peripheral cell.

Operating the adaptive array antenna
In this case, the phase information (direction of arrival) is superior to the amplitude information.
Therefore, at least the phase information (direction of arrival) is accurate.
It can be estimated. The information management unit 32 also
Weighting function f for mobile stations of users 1 to K in the own cell₁~
f_K, And weighting of neighboring cell users to mobile stations
Function f^Δ ₁~ F ^Δ _MMay be managed.

Next, a description will be added on how to determine the transmission weight (downlink) weight of each user in the own cell to the mobile station based on the arrival wave estimation from the own cell and neighboring cell mobile stations. deep. Basically, the calculation method of Document (2) shown in the prior art is used. Using the uplink signal, the base station 1 estimates the radio wave arrival direction θ _i from each mobile station and the propagation loss L _i . Any method may be used for estimating the direction of arrival of radio waves and estimating the propagation loss.

FIG. 6 is a conceptual diagram regarding an example of the propagation loss estimating means used in the second embodiment of the present invention. FIG. 6A shows the relationship between the transmission power of the base station, the reception power of the mobile station and the propagation loss, and FIG. 6B shows the transmission power of the mobile station and the reception power of the base station and the propagation loss. It shows the relationship with the loss. The concept of transmission weight calculation described with reference to FIG. 3 is extended to neighboring cells. The user of the own cell is distinguished by using the subscript i (i = 1 to K), and the users of the peripheral cells are distinguished by using the subscript j (j = 1 to M).

Regarding the method of estimating the propagation loss L _i , if the base station 1 knows the transmission power T _mi of the mobile station of the user i in its own cell, the reception power P _ri can be calculated using the following relational expression. Can be easily obtained from

[Equation 4] The mobile station 42 of the user j in the neighboring cell (j represents the user in the neighboring cell) can be easily obtained from the received power by using the same relational expression. In this case, the electric power is received by the base station 1 as an interference wave from a peripheral cell.

[Equation 5] Array propagation vectors (array direction vectors) determined by the estimated signal arrival directions of the i-th and j-th users, the downlink frequency, and the array shape are represented as v _i and v _j .

It is assumed that P _i is “the value assumed as the i-th user power of the own cell”, f _i is the weighting function of the i-th user of the own cell, and P _j is the “j-th user power of the neighboring cells”. Value, f _j is the weighting function of the j-th user of the peripheral cell, and Pn is the thermal noise power, the correlation matrix R _xx for weight calculation is

[Equation 6] It is defined as Here, the antenna weight w _k of the k-th user (k is a user in the own cell) is

[Equation 7] And give. R _xx ^-1 represents the inverse matrix of R _xx .

The above-mentioned “i-th user power of the own cell and
Value assumed as_iIs shown in FIG. 6 (b),
P_mi(= T_i/ L_i) Is substituted. On the other hand, "j
Value assumed for the user power of the eye "P_jIn Fig. 6 (b)
Shown in P_mj(= T_j/ L_j) Is substituted. Where L_jIs
Transmission between the base station 1 and the mobile station 42 of the user j in the neighboring cell
Carrying loss, T_jIs the neighboring cell base station 41
When transmitting the mobile station 42 of user j as the transmission partner
It is the value of the transmission power. The base station 1 is actually used by neighboring cells.
The transmission power T with the mobile station 42 of the j as the transmission partner _jSend by
It doesn't mean that you think like this virtually
Received by the mobile station 42 of the user j in the neighboring cell
Calculate and use the force value. In addition, T shown in FIG._i
From the base station 1 to the mobile station of user i in its own cell.
The value of the desired wave transmission power used as the transmission partner may be substituted.
Therefore, L obtained from the above equation (4)_iIs not necessarily
It is not needed. Similarly, the T shown in FIG._jNo
From the base station 41 of the neighboring cell, the user j in the neighboring cell
Of the desired wave transmission power with the mobile station 42 of
You may enter. Therefore, we obtain from equation (5) above.
L_jIs not necessarily required.

P _i and P _{j in} the equation (6) and P _{k in the} equation (7) determine the influence degrees of the i-th, j-th, and k-th users, respectively, in determining the transmit antenna directivity of the k-th user. To represent. Generally, when the mobile station of the user k in the own cell is the desired wave mobile station, the values of P _i (i ≠ k) and P _j are increased so that the mobile station of the user i in the own cell and its surroundings are increased. Cell user j
The null of the directivity can be intentionally pointed toward the mobile station 42 of the above. On the other hand, f _i and f _j are weighting functions, and interference with neighboring cells can be taken into consideration by inserting a positive value other than 0 into f _j , for example. In particular, if a large amount of interference with neighboring cells is desired to be suppressed, a large value may be entered for f _j .

Next, the above-mentioned weighting functions f _i and f _j will be described in detail. As described above, the short-term variation and the instantaneous variation are not considered, but the propagation loss due to the distance between the base station 1 and the mobile station is considered as the propagation loss information. That is, if the distance between the base station 1 and the mobile station of the user i is r _i , the received power fluctuation E (r _i ) is determined by the following equation. E (r _i ) = Ar ^−α (8) where A is a constant determined by transmission power and the like, and α is a propagation constant. The standard value of the propagation constant α in urban areas is α
= 3.5. Therefore, the above-mentioned propagation loss information L
_i is basically represented by the following equation. L _i = Br ^α (9) B is a constant.

However, according to the simulation described at the end, it has been found that the interference has a great influence on the mobile station located far away only by considering the above-mentioned propagation loss information L _i . Therefore, the weighting function f _i is defined as follows for the mobile station of the user i located at the distance r _i from the base station. f _i = r _i ^γ (γ> 0) (10) Note that the information management unit 32 shown in FIG. 4 uses the symbol of f _i ^Δ instead of f _j for mobile stations in neighboring cells. Is a function. The value of the weighting function f _i in the case of formula (10) is a function of the same distance r _i and the propagation loss information L _i, in estimating the path loss, as the propagation loss information L _i, received It is estimated from the power information Pr. Alternatively, the propagation loss information L _i to r _i
Can also be calculated.

FIG. 4 does not describe in which block the weighting functions f _i and f _j are calculated. Although it depends on the content of the weighting function to be set, it is calculated once for each user and stored in the information management unit 32. Alternatively, it can be obtained immediately before the weight calculation. Alternatively, as illustrated in FIG. 1, a weighting unit is provided after the conversion unit 15 to multiply the weighting functions f _i and f _j, and the transmission weight calculation unit 18 of the user-specific processing units 8 ₁ to 8 _K.
You may make it output to. However, when it is a function of the distance like the formula (10) or a function of the direction of arrival,
A method is possible in which the weight is calculated by obtaining the distance in the block for estimating the incoming wave.

This function receives the mobile station farther from the base station.
It works to increase the received power. I.e. a base station
Suppress interference from mobile stations farther from the base station than mobile stations closer
Act as you do. Therefore, in particular
When considering the mobile station, this weighting function f_i ^ΔIntroduce
It is effective. However, the explanation will be given with reference to FIGS.
It is also applicable to the first embodiment described.

If the above equation is combined with the above-mentioned propagation loss information L _i , then f _i / L _i = Br _i ^γ-α (γ> 0) (11). Therefore, it is possible to newly use the equation (12) as the propagation loss information. Note that the weighting functions f _i and f _i ^Δ in the above equations (11) and (12) are merely examples, and f _i and f _i ^Δ
A function having other characteristics may be used as long as it is a function that gives a better result than when = 1.

FIG. 7 is a block diagram for explaining the third embodiment of the present invention. 12, those parts that are the same as those corresponding parts in FIGS. 12 and 1 are designated by the same reference numerals, and a description thereof will be omitted.
This embodiment is a modification of the configuration of the embodiment described with reference to FIGS. 1 to 3, and has the effect of reducing the amount of interference by reducing the number of interfering users considered in transmission weight calculation. To improve. Reference numeral 51 is a selection unit, and 51 ₁ , 51 ₂ , ..., 51 _K are user 1,
2, ... K selection section. Each selection unit naturally selects the information of the incoming wave (desired wave) corresponding to each user, and also selects the information of the incoming wave corresponding to another user in order to suppress the interference wave.

At this time, the number of information of incoming waves is narrowed down to Ks (Ks ≦ K) including desired waves. Therefore, the degree of freedom in beam control of the array antenna during transmission increases. As a result, the effect of reducing the amount of interference is increased. It should be noted that when Ks = K, no narrowing down is performed, but depending on the situation, it may be possible to select incoming waves (desired wave + interference wave) of all users without performing narrowing down. Then, assuming such a case, Ks = K. For example, if the number Ks of incoming waves to be selected is reduced to less than the degree of freedom of the array antenna, the beam null can be directed to a mobile station that gives an interference wave.

Since the number of users K is usually much larger than the degree of freedom of the array antenna, a criterion for narrowing down the information of the interference wave selected for suppressing the interference wave is necessary. A first method of narrowing down interference waves is to select (Ks−1) pieces of mobile station information of users with high base station transmission power (high-rate receiving users) in order from the top. Using these information, when a beam pattern that generates nulls is generated for (Ks−1) high-rate receiving users when the main lobe is transmitted to the low-rate receiving users in the downlink, high-speed Interference for rate receiving users is reduced. As a result, it becomes possible to reduce the transmission power when the main lobe is transmitted to the high-rate receiving user, and when the main lobe is transmitted to the high-rate receiving user, the interference to the low-rate receiving user is reduced. Is reduced.

The second method of narrowing down interference waves is the reverse of the first method described above. This is to select (Ks−1) pieces of mobile station information of interfering users with low base station transmission power (low-rate reception users) in order from the lower order. Using these information, when a beam pattern that generates nulls is generated for (Ks−1) low-rate receiving users when the main lobe is transmitted to the high-rate receiving users in the downlink, the low speed is generated. Interference to rate receiving users is directly reduced. In any case, by narrowing down the number of interference waves to be considered, the beam null can be directed in a desired direction, and the effect of suppressing interference waves is enhanced.

The third method of narrowing down the interference wave is to summarize the arrival waves used for the calculation of the arrival angles of a large number of arrival waves received by the base station. FIG. 8 is a principle explanatory diagram of a third method of narrowing down interference waves used for calculation in the third embodiment shown in FIG. It is assumed that 10 users are communicating at the same time, and the selection unit 51 of the user 10 will be exemplarily described. FIG. 8A is a diagram showing the arrival angle of the incoming wave and the received power managed by the information management unit 22. The arrival angle of the incoming wave from the user _i θ 'i,
Let the received power be P ′ _i . i = 10 relates to the reference wave for the user 10, and i = 1 to 9 are received as interference waves for the user 10.

Here, the entire range of the arrival angle θ is divided by Δθ, and when there are a plurality of interference waves in the divided small sections, the adjacent arrival waves in the small section are combined and 1
By selecting the one replaced with one interference wave,
It is used for transmission weight calculation after reducing the number of incoming wave information. As a gathering method, for example, FIG.
There are methods of (b), FIG. 8 (c), and FIG. 8 (d). Less than,
The arrival angle and the reception power of one interfering wave selected by replacement are (θ ₁ , P ₁ ), (θ ₂ ,
Let P ₂ ), (θ ₃ , P ₃ ), (θ ₄ , P ₄ ) ...

In either case, the selected received power P ₁ ,
As shown in the figure, P ₂ and P ₃ are the sum of received power in each small section. That is, P ₁ = P ' ₁ + P' ₂ + P ' ₃ P ₂ = P' ₄ P ₃ = P ' ₅ + P' ₆ + P ' ₇ P ₄ = P' ₈ + P ' ₉

In FIG. 8B, the arrival angle θ of the selected interference wave is the arrival angle of the path (arrival wave) having the maximum received power in each small section. That is, θ ₁ = θ ′ ₂ , θ ₂ = θ ′ ₄ , θ ₃ = θ ′ ₇ , θ ₄ = θ ′ _{9 In} FIG. 8C, the arrival angle θ of the selected interference wave is
Is the arrival angle weighted and combined with the received power in each small section as a weight. That is, θ ₁ = (P ' ₁ θ' ₁ + P ' ₂ θ' ₂ + P ' ₃ θ' ₃ ) / (P ' ₁ + P' ₂ + P '
_{3) θ 2 = θ '4} θ 3 = (P' 5 θ '5 + P' 6 θ '6 + P' 7 θ '7) / (P' 5 + P '6 + P'
₇ ) θ ₄ = (P ′ ₈ θ ′ ₈ + P ′ ₉ θ ′ ₉ ) / (P ′ ₈ + P ′ ₉ ) In FIG. 8D, the arrival angle θ of the selected interference wave is
Is the median of each small section. That is, when the arrival angle where the vertical axis is located is 0, θ ₁ = (1/2) Δθ, θ ₂ = (3/2) Δθ, θ ₃ = (5/2) Δθ, θ
₄ = (7/2) Δθ

In the above-described interference wave narrowing-down method,
The interference power may not be selected unless it is equal to or more than a predetermined threshold value determined according to the average power or the like. In this case, when the reception power of the desired wave from a certain user is less than or equal to this threshold, the value of the interference wave selection number Ks of this user may be depending on the narrowing method or the distribution of the reception power at that time,
It may be different from the value of the interference wave selection number Ks of other users.

FIG. 9 is a block diagram for explaining the fourth embodiment of the present invention. 12, those parts that are the same as those corresponding parts in FIGS. 12, 1, 4, and 7 are designated by the same reference numerals, and a description thereof will be omitted. This embodiment is a modification of the configuration of the embodiment described with reference to FIGS. 4 to 6, and similarly to FIG. By reducing the amount, the effect of reducing the amount of interference is enhanced. That is, from the (K + M) including the arriving waves from the neighboring cell users, only Ks pieces of arriving waves to be considered in the transmission weight calculation are selected including the desired wave. The selection criteria are the same as in the case of FIG. Further, when the third method is adopted, the arrival angles of the incoming waves as illustrated in FIG. 8 can be put together.

FIG. 10 is a diagram for explaining the simulation result for evaluating the effect of suppressing the interference wave by considering the mobile stations in the peripheral cells. Although it does not represent the result of carrying out the present invention, the expected effects can be estimated by applying the present invention. Cell composition
It is a regular hexagonal cell with R [km]. Mobile stations are uniformly distributed in the cell. Considering only the distance variation as the propagation variation, the propagation constant α is set to 3.5. The array antenna configuration is a linear array antenna, and the antenna elements are omnidirectional.

The inter-code interference is 0 if the spread codes are completely orthogonal, but if the orthogonal relationship is broken, interference of 1 / PG (PG: spreading factor) occurs. In general, radio waves transmitted from the same base station have an orthogonal relationship and have no interference. However, if there is a propagation delay wave, the orthogonal relationship between the spreading codes is broken and interference occurs. For simplicity, the interference rate (hereinafter referred to as non-orthogonal coefficient) is defined as β and used. That is, the amount of interference is β / PG. On the other hand, signals transmitted from different base stations generally cannot maintain the orthogonal relationship, and thus cause 1 / PG interference.

(1) The number of mobile stations in each cell is classified into two transmission rate mobile station groups (high-speed transmission mobile station group and low-speed transmission mobile station group), and the transmission power is determined. Then, the position of the mobile station is determined for each cell by a uniform random number. (2) At the base station, it is assumed that the arrival direction and propagation loss of each mobile station can be ideally estimated at the base station side. Based on the estimated information, the downlink transmission power is converted and the weighting function is added for each mobile station according to the transmission rate, the array vector is created, and the antenna pattern is obtained. (3) At each mobile station, the desired wave power and the interference wave power are obtained based on the downlink antenna pattern, transmission power, and propagation loss. The interference wave power is the total power of the interference wave of the own cell (total number of users in cell-1) and the interference waves from other cells (total number of users in cell x number of other cells). Is calculated in consideration of the non-orthogonal component β / PG and 1 / PG (β = 1) for interference waves of other cells. The trials of (1) to (3) are repeated to find the distribution of the desired wave power to interference wave power ratio CIR. However, the evaluation was performed only on the mobile station in the central cell where the interference is the most severe.

The simulation conditions are as follows. Focusing on the allocation frequency of the third-generation mobile communication in Japan, when the antenna element interval d is set to λ / 2 with respect to the carrier frequency of the uplink, the carrier frequency of the downlink is about It becomes 0.55λ. The number of antenna elements is 8 and the number of mobile stations in each cell is 20.
Although not illustrated here, the number of high-speed transmission mobile stations is 5 and the number of low-speed transmission mobile stations is 15 when the transmission speed is taken into consideration.
I am trying. The transmission power of the high-speed transmission mobile station group is set to 15 dB higher than that of the low-speed transmission mobile station group.

The evaluation is compared with the method shown below. (i) A method that uses the antenna weight calculated in the uplink as the weight of the downlink (downlink COPY method) (ii) The method is to correct and calculate the optimum antenna weight (downlink optimal method). That is, this is the case where f _i = 1 (γ = 0). (iii) For reference, in the case of time division multiple access TDD with f _i = 1 (γ = 0) and the same carrier frequencies for transmission and reception (TDD method)
Also showed.

FIG. 10A shows a desired wave power to interference wave power ratio CIR / PG when the exponent part γ of the weighting function is used as a parameter.
The cumulative distribution of is shown. However, it is assumed that all mobile stations belong to the low-speed transmission mobile station group, and the non-orthogonal coefficient β is β = 0.4. For example, γ =
Significant CIR / PG improvements are obtained in 3.5-5. For example, if γ = 3.5, it can be seen that the proposed method can significantly improve CIR / PG compared to the downlink COPY method and the downlink optimal method (equivalent to the case of γ = 0).

By the way, the above results are simulation results when the arrival directions and propagation losses of all mobile stations are known. However, it is not always realistic when the arrival directions and propagation losses of all mobile stations are known. Therefore, we also conducted evaluations by limiting the range in which the information on the arrival direction and propagation loss of mobile stations can be obtained. In FIG. 10B, the range Rth in which the mobile station information can be obtained is set to 1, 1.2, 1.5 of the cell radius R.
The cumulative distribution of CIR / PG is shown for double and ∞. However, it is assumed that all mobile stations belong to the low-speed transmission mobile station group, the exponent part of the weighting function is γ = 3.5, and the non-orthogonal coefficient is β.
= 0.4.

As can be seen from this diagram, the larger the range Rth in which mobile station information can be obtained, the better the CIR / PG. For example, comparing with the 20% value of cumulative probability, the proposed method has about 3 dB at Rth = R and about 3 dB at Rth = 1.2R compared to the downlink COPY method.
A 5 dB improvement is obtained. In addition, even when compared to the TDD method, R
An improvement effect of about 1 dB is obtained at th = 1.2R. Although not shown, the proposed method can significantly improve the CIR / PG compared with the conventional method even when a high-speed transmission mobile station and a low-speed transmission mobile station coexist. When Rth = R, the range is almost that of the own cell, but since the own cell is a regular hexagonal cell with one side of R, the influence of mobile stations of neighboring cells is partly included.

In the above description, the calculation of the transmission array antenna weight in the downlink direction from the base station has been described. However, it is only necessary to control the beam pattern of the array antenna so as to have a desired characteristic by estimating the incoming wave. In the present invention, the shape of the array antenna and the polarization to be handled are not particularly limited. Further, there are no particular restrictions on the number of array antenna elements or the element spacing. Further, it can be applied to both the FDD system and the TDD system. The above description has explained the base station antenna directivity control apparatus in the CDMA cellular system configured by a plurality of cells. However, it can also be used for a base station antenna directivity control device in a CDMA system in which a plurality of mobile stations exist in one independent coverage area. Further, even in the CDMA cellular system, when the influence of mobile stations in neighboring cells is not considered, it is substantially the same as the base station apparatus in the CDMA system described above.

[0087]

As is apparent from the above description, according to the present invention, it is possible to improve the estimation accuracy of the interference wave and to consider the influence of the interference wave from the neighboring cells, thereby making it possible to realize a plurality of antenna elements. The effect is that the optimum transmission weight for Further, there is an effect that the optimum transmission weights for a plurality of antenna elements can be accurately calculated by considering the degree of the influence of the interference wave on the distance. The optimal transmission weight for the antenna device having a plurality of antenna elements improves the effect of suppressing the amount of interference more than before, and as a result, the number of users that can be accommodated in the cell is increased and the frequency utilization rate is improved.

[Brief description of drawings]

FIG. 1 is a block configuration diagram for explaining a first embodiment of a base station antenna directivity control device in a CDMA cellular system of the present invention.

FIG. 2 is an explanatory diagram showing weight calculation of array antennas in all the user-specific processing units in FIG. 1;

FIG. 3 is a conceptual diagram related to an example of propagation loss estimation used in the first embodiment of the present invention.

FIG. 4 is a block configuration diagram for explaining a second embodiment of the present invention.

5 is an explanatory diagram of an example in which an incoming wave from a mobile station in a peripheral cell shown in FIG. 2 extracts an incoming wave from a mobile station in a peripheral cell from a plurality of estimated arrival directions; FIG. is there.

FIG. 6 is a conceptual diagram related to an example of propagation loss estimation used in the second embodiment of the present invention.

FIG. 7 is a block configuration diagram for explaining a third embodiment of the present invention.

8 is a principle explanatory diagram of a third method of narrowing down an interference wave used for calculation in the third embodiment shown in FIG. 7. FIG.

FIG. 9 is a block configuration diagram for explaining a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a simulation result for evaluating the effect of suppressing interference waves by considering mobile stations in neighboring cells.

FIG. 11 is an explanatory diagram showing an example of a CDMA cellular mobile communication system using an adaptive array antenna.

FIG. 12 is a block configuration diagram for explaining an example of a base station antenna directivity control device in a conventional CDMA cellular system.

FIG. 13 is a block diagram schematically illustrating a weight calculation of the conventional adaptive array antenna using the DOA estimation.

FIG. 14 is an explanatory diagram of transmission weight calculation in all the user-specific processing units in FIG. 12;

[Explanation of symbols]

1 ... Base station, 2 ... User 1 mobile station, 3 ... User 2 mobile station, 4a-4d ... Array antenna element, 8 _1-
8 _K ... User-specific processing unit, 11 ... AAA (adaptive array antenna) receiving unit, 13 ... Desired wave estimating unit, 14, 2
2, 32 ... Information management unit, 15 ... Conversion unit, 17 ... AAA transmission unit, 18 ... Transmission weight calculation unit, 21 ... RF reception unit,
41 ... Base station of peripheral cell, 42 ... Mobile station of peripheral cell user 1, 51 ... Selection unit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K022 EE01 EE21 EE31                 5K059 CC02 DD10 EE02                 5K067 AA03 AA22 CC10 EE10 KK03

Claims (14)

[Claims] 1. A base station antenna directivity control device in a CDMA system for performing communication with a plurality of user communication devices by using an antenna device having a plurality of antenna elements, wherein the plurality of antenna elements are provided. Desired wave estimating means for estimating a desired wave received from each of the user communication devices based on received signals of a plurality of systems received by the device, and outputting incoming wave information regarding the respective user communication devices, and each of the user communication devices Information management means for managing the arrival wave information regarding the information and the transmission power information of the signal to be transmitted to each user communication device, and the user communication device to be a transmission partner by using the managed information regarding each user communication device. To generate a beam pattern in which the directivity gain to the user communication device is large and the directivity gain to the other user communication devices is small,
A base station antenna directivity control device in a CDMA system, comprising: an antenna weight output means for calculating and outputting an antenna weight for each antenna element for each user communication device that is a transmission partner. 2. The desired wave estimating means estimates only the arrival direction of the desired wave and outputs only the arrival direction information as the arrival wave information regarding each of the user communication devices. A base station antenna directivity control device in the CDMA system according to claim 1. 3. The incoming wave information regarding the user communication device as the communication partner from the information management means, and
While selecting the transmission power information, there is an information selection unit that narrows down the incoming wave information regarding the other user communication device and the transmission power information and outputs the information to the antenna weight output unit. A base station antenna directivity control device in the CDMA system according to claim 1. 4. The information selecting means reduces the number of pieces of arrival wave information by combining pieces of arrival wave information of the other user communication device whose arrival angles are close to each other, and combines the pieces of arrival information. The transmission power information is combined according to the arrival wave information, and the arrival direction information regarding the combined arrival wave information and the combined transmission power information are used as the information regarding the other user communication device. The base station antenna directivity control device in the CDMA system according to claim 3, wherein the weight output means outputs the weight to the base station antenna directivity control device. 5. A receiving means for outputting reception information by calculating a reception weight for each antenna element for each user communication device as a reception partner based on the reception signals of a plurality of systems received by the plurality of antenna elements. The desired wave estimating means estimates the desired wave received from each of the user communication devices by using an intermediate calculation result of the receiving means. A base station antenna directivity control device in the CDMA system according to any one of items. 6. A base station antenna directivity control device in a CDMA cellular system for performing communication with a plurality of user communication devices of its own cell using an antenna device having a plurality of antenna elements, comprising: Arrival wave information regarding each user communication device of the own cell is estimated by estimating a desired wave received from each user communication device of the own cell based on the reception signals of a plurality of systems received by the plurality of antenna elements of the own cell. A desired wave estimating means for outputting, and estimating an incoming wave received from each user communication device of a peripheral cell based on a plurality of systems of received signals received by a plurality of antenna elements of the own cell, the peripheral cell Peripheral cell arrival wave estimation means for outputting arrival wave information regarding each user communication device, and arrival wave information regarding each user communication device in the own cell and each user in the own cell Transmission power information of a signal transmitted to a communication device, arrival wave information regarding each user communication device of the peripheral cell, and transmission power information of a transmission signal transmitted from a base station of the peripheral cell to each user communication device of the peripheral cell A user of the own cell that is a transmission partner by using an information managing unit that manages the information, a managed information of each user communication device of the own cell, and a managed information of each user communication device of the neighboring cell. Each antenna of the own cell so as to generate a beam pattern having a large directional gain to the communication device and a small directional gain to other user communication devices of the own cell and user communication devices of the peripheral cells. Antenna weight output means for calculating and outputting the antenna weight for the element for each user communication device of the own cell that is the transmission partner, A base station antenna directivity control apparatus in a CDMA cellular system, comprising: 7. The desired wave estimating means estimates only the arrival direction of the desired wave and outputs only the arrival direction information as the arrival wave information regarding each of the user communication devices. 7. The estimating means estimates only the arrival direction of the arrival wave and outputs only the arrival direction information as the arrival wave information regarding each user communication device of the peripheral cell. Base station antenna directivity control device in the CDMA cellular system of. 8. The incoming wave information regarding the user communication device of the own cell which is the transmission partner from the information management means,
And selecting the transmission power information and narrowing down the incoming wave information and the transmission power information regarding other user communication devices of the own cell and user communication devices of the neighboring cells, and the antenna weight output means. The base station antenna directivity control device in the CDMA cellular system according to claim 6 or 7, further comprising: an information selection unit that outputs the information to the base station antenna directivity control device. 9. The information selecting means combines the arrival wave information from the other user communication devices of the own cell and the user communication devices of the neighboring cells by synthesizing information of which arrival angles are close to each other. The number of pieces of wave information is reduced, the transmission power information is combined according to the combined arrival wave information, the arrival direction information regarding the combined arrival wave information, and the combined transmission power 9. The base station antenna directivity control apparatus in the CDMA cellular system according to claim 8, wherein the information is output as information regarding another user communication apparatus of the own cell and a user communication apparatus of a peripheral cell. 10. The reception is performed by calculating the reception weight for each antenna element for each user communication device of the own cell which is a reception partner based on the reception signals of a plurality of systems received by the plurality of antenna elements of the own cell. It has a receiving means which outputs information, The said desired wave estimation means estimates the desired wave received from each said user communication apparatus using the intermediate calculation result in the said receiving means, It is characterized by the above-mentioned. Item 10. A base station antenna directivity control device in the CDMA cellular system according to any one of items 6 to 9. 11. A base station antenna directivity control device in a CDMA system for communicating with a plurality of user communication devices by using an antenna device having a plurality of antenna elements, the arrival of each of the user communication devices. Direction information, propagation loss information, transmission power information, and a pointing to the user communication device that is a transmission partner by using a weighting function for reducing interference given to each user communication device that is far from the base station. Antenna weight for each antenna element is calculated for each user communication device that is a transmission partner so as to generate a beam pattern in which the directional gain is large and the directional gain with respect to the other user transmitting device is small. A base station antenna directivity control device in a CDMA system characterized by outputting. 12. Correlation relating to a received signal of each user communication device by regarding a value obtained by multiplying a transmission power for each user communication device by the weighting function and considering a propagation loss as a received power expected value of each user communication device. Generate a matrix,
The base station antenna directivity control device in the CDMA system according to claim 11, wherein an antenna weight for each of the antenna elements is calculated for each user communication device that is the transmission partner. 13. A base station antenna directivity control apparatus in a CDMA cellular system, which communicates with a plurality of user communication apparatuses of its own cell using an antenna apparatus having a plurality of antenna elements, said self cell Direction of arrival information about each user communication device of
Propagation loss information, transmission power information, direction-of-arrival information about each user communication device of the neighboring cell, propagation loss information, transmission power information about transmission power transmitted by the base station of the neighboring cell to each user communication device of the neighboring cell, And, the distance from the base station of the own cell is far, using a weighting function for reducing the interference given to each user communication device of the own cell and each user communication device of the peripheral cell, the transmission partner Each of the beam patterns is generated such that the directivity gain of the own cell to the user communication device is large and the directivity gain of the other user communication device of the own cell and the user communication devices of the peripheral cells is small. A CD characterized in that an antenna weight for an antenna element is calculated and output for each user communication device of the own cell that is the transmission partner. A base station antenna directivity control device in the MA cellular system. 14. A transmission power for each user communication device of the own cell is multiplied by the weighting function, and a value considering a propagation loss is regarded as a reception power assumed value of each user communication device of the own cell, and The transmission power from the base station of the peripheral cell for each user communication device of the peripheral cell is multiplied by the weighting function, and a value considering the propagation loss is regarded as a reception power assumed value of each user communication device of the peripheral cell. The correlation matrix for the received signal of the user communication device is generated, and the antenna weight for each of the antenna elements is calculated and output for each user communication device that is the transmission partner. A base station antenna directivity control device in a CDMA cellular system.