JP7020003B2 - Wireless communication devices, systems, methods and programs - Google Patents

Description

The present invention relates to wireless communication devices, systems, methods and programs that use adaptive array antennas.

A radio base station that does not use an adaptive array antenna cannot control transmission power according to the orientation of the mobile station. For example, if there is strong cell-to-cell interference between the cell in which the mobile station is located and its adjacent cell, the radio base station reduces the transmission power of its own cell to move the mobile station to the adjacent cell. Therefore, it is possible to alleviate the interference between cells. However, since a radio base station that does not use an adaptive array antenna reduces transmission power in directions other than the direction of the mobile station, a coverage hole that is not covered by any radio base station cell may occur. On the contrary, if the transmission power of the radio base station is increased so as to improve the reception condition of a certain mobile station, the interference between cells may be increased, and as a result, the reception condition of another mobile station may be deteriorated. There is.

On the other hand, a radio base station using an adaptive array antenna can alleviate the above-mentioned problem by performing transmission control according to the direction of the mobile station.

For example, in the method described in Patent Document 1, the direction of arrival of the uplink signal from the mobile station is estimated, and the directivity of the adaptive array antenna is determined based on the direction of arrival. Further, in the method described in Patent Document 2, the output azimuth information and time information of the directional beam when each radio base station transmits a downlink signal are shared with other radio base stations, and based on the information. , It is determined at what timing and to which mobile station the downlink signal is transmitted.

However, in these methods, while the signal quality is improved by controlling the transmission power by beamforming to the mobile station in the service area, the interference with the adjacent cell increases when there is an area where the cell-to-cell interference is constantly strong. There is a possibility (Fig. 25). Further, when there are a large number of mobile stations, dynamically performing power control for each mobile station may increase the processing load of the radio base station (FIG. 26).

On the other hand, in the method described in Patent Document 3, the radio base station estimates the direction of arrival of the interference wave from the surrounding radio base stations, and controls the transmission power based on the estimation result. As a result, cell-to-cell interference and processing load can be reduced.

Japanese Unexamined Patent Publication No. 2013-207422 Japanese Unexamined Patent Publication No. 2005-159849 JP-A-2015-046713

In the method described in Patent Document 3, the arrival direction of the interference wave is estimated. However, when estimating the arrival direction of the interference wave, it is necessary to add a function that involves hardware modification to a general wireless base station and to add a new function to both the transmitting side / receiving side wireless base station. .. In addition, due to the influence of fading and the like, cell-to-cell interference does not always occur around the mobile station in the direction of arrival of the interference wave.

It is an object of the present invention to provide radio communication devices, systems, methods and programs that make it possible to optimize cells of radio base stations to improve radio communication quality in an easier and more accurate way. There is something in it.

In order to solve the above-mentioned problems, in the wireless communication device of the present invention, the wireless communication unit that performs wireless communication with the terminal, the direction estimation unit that estimates the arrival direction of the uplink signal from the terminal, and the terminal measure the signal. It is provided with an electric field information receiving unit that receives electric field information of a downlink signal from the terminal, and a transmission power determining unit that determines the transmission power of the wireless communication based on the statistical information of the electric field information and the arrival direction. It is characterized by.

Further, in the wireless communication method of the present invention, wireless communication is performed with a terminal, the arrival direction of an uplink signal from the terminal is estimated, electric field information of a downlink signal measured by the terminal is received from the terminal, and the electric field is received. It is characterized in that the transmission power of the wireless communication is determined based on the statistical information of the information and the arrival direction.

Further, the wireless communication program of the present invention has a wireless communication function for wirelessly communicating with a terminal in a computer, an orientation estimation function for estimating the arrival direction of an uplink signal from the terminal, and a downlink signal measured by the terminal. It is characterized by realizing an electric field information receiving function that receives electric field information from the terminal and a transmission power determination function that determines the transmission power of the wireless communication based on the statistical information of the electric field information and the arrival direction. do.

The wireless communication devices, systems, methods and programs of the present invention make it possible to optimize the cells of a wireless base station and improve the wireless communication quality in an easier and more accurate manner.

It is a figure which shows the structural example of the wireless communication apparatus of 1st Embodiment of this invention. It is a figure which shows the operation example of the wireless communication apparatus of 1st Embodiment of this invention. It is a figure which shows the structural example of the wireless communication system of the 2nd Embodiment of this invention. It is a figure which shows the structural example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the structural example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the structural example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the structural example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the operation example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the operation example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the operation example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the operation example of the wireless communication apparatus of the 2nd Embodiment of this invention. It is a figure which shows the example of a coverage hole. It is a figure which shows the example of a high interference area. It is a figure which shows the example of the aggregation result of the number of terminals of the 2nd Embodiment of this invention. It is a figure which shows the example of the sorting result of the direction of the 2nd Embodiment of this invention. It is a figure which shows the example of own cell before transmission power control of the 2nd Embodiment of this invention. It is a figure which shows the example of own cell after transmission power control of the 2nd Embodiment of this invention. It is a figure which shows the example of the azimuth number and the electric field strength of the 2nd Embodiment of this invention. It is a figure which shows the example of the number of terminals with respect to the combination of each direction and each electric field strength of the 2nd Embodiment of this invention. It is a figure which shows the example of the number of low electric field terminals and the number of high interference terminals for each direction of the 2nd Embodiment of this invention. It is a figure which shows the example of the sorting result of the direction of the 2nd Embodiment of this invention. It is a figure which shows the example of the control result of the maximum transmission power of the 2nd Embodiment of this invention. It is a figure which shows the example of own cell after power control of the 2nd Embodiment of this invention. It is a figure which shows the hardware configuration example of each embodiment of this invention. It is a figure which shows that the interference of other terminals increases as a result of beamforming. It is a figure which shows that the processing load increases by performing beamforming to a large number of terminals.

[First Embodiment]
The first embodiment of the present invention will be described.

FIG. 1 shows a configuration example of the wireless communication device 10 of the present embodiment. The wireless communication device 10 of the present embodiment includes a wireless communication unit 11, an arrival direction estimation unit 12, an electric field information receiving unit 13, and a transmission power determination unit 14.

The wireless communication unit 11 is a unit that performs wireless communication with the terminal. The arrival direction estimation unit 12 is a unit that estimates the arrival direction of the upstream signal from the terminal. The electric field information receiving unit 13 is a portion that receives the electric field information of the downlink signal measured by the terminal from the terminal. The transmission power determination unit 14 is a unit that determines the transmission power of wireless communication based on the statistical information of the electric field information and the arrival direction.

By configuring the wireless communication device 10 in this way, the wireless communication device 10 can perform wireless communication based on the statistical information of the electric power information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. Determine the transmission power. The electric field information of the downlink signal is the information measured by a general terminal. Further, by using the electric field information measured by the terminal, the wireless communication device 10 can more accurately transmit the transmission power of the wireless communication based on the actual electric field information in the terminal for the downlink signal affected by fading or the like. It will be possible to decide. Further, by using the statistical information of the electric field information, the wireless communication device 10 can collect a large amount of electric field information of the downlink signal affected by various conditions, so that the transmission power of the wireless communication can be obtained more accurately. It will be possible to decide. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

Next, FIG. 2 shows an example of the operation of the wireless communication device 10 of the present embodiment.

The arrival direction estimation unit 12 estimates the arrival direction of the upstream signal from the terminal (step S101). The electric field information receiving unit 13 receives the electric field information measured by the terminal from the terminal (step S102). The transmission power determination unit 14 determines the transmission power of wireless communication based on the statistical information of the electric field information and the arrival direction (step S103).

By operating in this way, the wireless communication device 10 determines the transmission power of wireless communication based on the statistical information of the electric field information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. .. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

As described above, in the first embodiment of the present invention, the wireless communication device 10 is based on the statistical information of the electric field information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. , Determine the transmission power of wireless communication. The electric field information of the downlink signal is the information measured by a general terminal. Further, by using the electric field information measured by the terminal, the wireless communication device 10 can more accurately transmit the transmission power of the wireless communication based on the actual electric field information in the terminal for the downlink signal affected by fading or the like. It will be possible to decide. Further, by using the statistical information of the electric field information, the wireless communication device 10 can collect a large amount of electric field information of the downlink signal affected by various conditions, so that the transmission power of the wireless communication can be obtained more accurately. It will be possible to decide. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

[Second embodiment]
Next, a second embodiment of the present invention will be described. In this embodiment, the wireless communication device of the first embodiment will be described more specifically.

First, FIG. 3 shows a configuration example of the wireless communication system of the present embodiment. The wireless communication system of this embodiment is composed of a wireless communication device 20 and a terminal 60. It is possible that one or more wireless communication devices 20 and terminals 60 each exist in the wireless communication system. The wireless communication device 20 corresponds to a base station for wireless communication, and the terminal 60 corresponds to a mobile station.

Next, FIGS. 4 to 7 show a configuration example of the wireless communication device 20 of the present embodiment.

The wireless communication device 20 includes an antenna 21 (21a to 21d), a switch 22 (22a to 22d), a received signal processing unit 23, a demodulation / decoding unit 24, a transmission power determination unit 25, a coding / modulation unit 26, and a transmission signal processing. It is composed of a part 27 (FIG. 4).

The antenna 21 is a portion that transmits / receives RF (Radio Frequency) signals to and from the terminal 60 located in the cell of the wireless communication device 20. Further, the antenna 21 transmits / receives an RF signal to / from the switch 22. Although the adaptive array antenna method using four antennas is used in the configuration example of FIG. 4, another adaptive array antenna method may be used.

The switch 22 is a part that transmits the received RF signal to the received signal processing unit 23 and transmits the transmitted RF signal from the transmission signal processing unit 27 to the antenna 21.

The received signal processing unit 23 is a unit that synthesizes the received RF signal from the switch 22 and transmits it to the demodulation / decoding unit 24. Further, the reception signal processing unit 23 estimates the direction of arrival of the uplink signal from the terminal 60, and transmits the estimation result to the transmission power determination unit 25 and the transmission signal processing unit 27.

The demodulation / decoding unit 24 is a unit that demodulates / decodes the combined received RF signal into a received data signal.

The transmission power determination unit 25 determines the transmission power of wireless communication based on the statistical information of the electric field information included in the received data signal and the arrival direction of the uplink signal of the terminal 60 estimated by the reception signal processing unit 23. Is.

The coding / modulation unit 26 is a unit that encodes / modulates the transmission data signal into a synthetic transmission RF signal and transmits it to the transmission signal processing unit 27.

The transmission signal processing unit 27 is a unit that transmits a transmission RF signal from the antenna 21 via the switch 22 based on the transmission power determined by the transmission power determination unit 25.

The antenna 21, the switch 22, the received signal processing unit 23, the demodulation / decoding unit 24, the coding / modulation unit 26, and the transmission signal processing unit 27 correspond to the wireless communication unit 11 in FIG. The transmission power determination unit 25 corresponds to the transmission power determination unit 14 in FIG.

The configuration example of FIG. 4 is based on the TDD (Time Division Duplexing) method using a common switch for transmission and reception, but the configuration of the wireless communication device 20 is an FDD (Frequency Division Duplexing) method using different switches for transmission and reception. It may be due to.

Next, a configuration example of the received signal processing unit 23 of the wireless communication device 20 of the present embodiment will be described (FIG. 5). The reception signal processing unit 23 includes an amplifier 231 (231a to 231d), a multiplier 232 (232a to 232d), a synthesizer 233, and a receiving side adaptive processor 234. The receiving side adaptive processor 234 is composed of an arrival direction estimation unit 235 and a reception weight calculation unit 236.

The amplifier 231 is a portion that amplifies the received RF signal. This amplified received RF signal is called an intermediate processing received RF signal.

The multiplier 232 is a portion that multiplies the received RF signal for intermediate processing by the received weight based on the received weight calculated by the received weight calculation unit 236.

The synthesizer 233 is a part that synthesizes the received RF signal for intermediate processing after weight multiplication and transmits it to the receiving side adaptive processor 234 and the demodulation / decoding unit 24.

The arrival direction estimation unit 235 is a part that receives the received RF signal for intermediate processing and the combined reception RF signal and estimates the arrival direction of the uplink signal from the terminal 60. The arrival direction estimation unit 235 corresponds to the arrival direction estimation unit 12 in FIG.

The reception weight calculation unit 236 is a unit that calculates the reception weight based on the arrival direction estimated by the arrival direction estimation unit 235 and the combined reception RF signal.

Although the configuration example of FIG. 5 is an example in which a general adaptive array reception processing system is used, another adaptive array reception processing system may be used.

Next, a configuration example of the transmission signal processing unit 27 of the wireless communication device 20 of the present embodiment will be described (FIG. 6). The transmission signal processing unit 27 includes an amplifier 271 (271a to 271d), a multiplier 272 (272a to 272d), a distributor 273, and a transmission side adaptive processor 274. Further, the transmission side adaptive processor 274 is configured by the transmission weight calculation unit 275.

The distributor 273 is a portion that receives the combined transmission RF signal from the coding / modulation unit 26 and distributes it to the multiplier 272. The distributed signal is called an intermediate processing transmission RF signal.

The multiplier 272 is a portion that multiplies the transmission weight for intermediate processing by the transmission weight according to the transmission weight calculated by the transmission side adaptive processor 274.

The amplifier 271 is a portion that amplifies the transmission RF signal for intermediate processing multiplied by the weight and transmits it to the switch 22.

The transmission weight calculation unit 275 is a unit that calculates the transmission weight based on the transmission power determined by the transmission power determination unit 25 and the arrival direction of the uplink signal of the terminal 60.

Although the configuration example of FIG. 6 is an example in which a general adaptive array transmission processing system is used, another adaptive array transmission processing system may be used.

Next, a configuration example of the transmission power determination unit 25 of the wireless communication device 20 of the present embodiment will be described (FIG. 7). The transmission power determination unit 25 is composed of an information storage unit 251, a statistical information processing unit 254, a transmission direction / power determination unit 255, and an electric field information reception unit 256. Further, the information storage unit 251 is composed of an arrival direction storage unit 252 and an electric field information storage unit 253.

The arrival direction storage unit 252 is a part that stores the arrival direction of the upstream signal of the terminal 60 estimated by the arrival direction estimation unit 235 together with the time information.

The electric field information receiving unit 256 is a part for storing the electric field information included in the received data signal demodulated / decoded by the demodulation / decoding unit 24 in the electric field information storage unit 253. The electric field information is the measurement information for the downlink signal from the wireless communication device 20 measured by the terminal 60. The electric field information receiving unit 256 can extract electric field information from, for example, a Measurement Report of LTE (Long Term Evolution). The electric field information is, for example, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), CQI (Channel Quality Indicator) and the like. The electric field information receiving unit 256 corresponds to the electric field information receiving unit 13 in FIG.

The electric field information storage unit 253 is a portion that stores electric field information. The electric field information storage unit 253 stores the terminal ID (Identification) and the electric field information together with the time information for the terminal 60 located in the cell of the wireless communication device 20.

The statistical information processing unit 254 is a part that performs statistical processing based on the statistical information of the electric field information and the arrival direction. In the present embodiment, the statistical information processing unit 254 first determines whether each terminal 60 is a low electric field terminal or / or a high interference terminal based on the statistical information of the electric field information. Then, the maximum transmission power (maximum value of transmission power) in each direction is determined based on the determination result of the low electric field terminal / high interference terminal and the arrival direction of the terminal 60.

By performing statistical processing based on the statistical information of the electric field information and the direction of arrival, the wireless communication device 20 can grasp the state of the electric field in each direction (which direction has the low electric field / high interference area). It will be possible. Then, the cell can be optimized by determining the maximum transmission power in each direction according to the state of the electric field in each direction.

The transmission direction / power determination unit 255 is a part that determines the transmission direction / transmission power based on the result of statistical processing of the statistical information processing unit 254. In the present embodiment, the transmission power to each direction is determined based on the maximum transmission power of each direction determined by the statistical information processing unit 254.

By configuring the wireless communication device 20 in this way, the wireless communication device 20 can perform wireless communication based on the statistical information of the electric power information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. Determine the transmission power. The electric field information of the downlink signal is the information measured by a general terminal. Further, by using the electric field information measured by the terminal, the wireless communication device 20 can more accurately transmit the transmission power of the wireless communication based on the actual electric field information in the terminal for the downlink signal affected by fading or the like. It will be possible to decide. Further, by using the statistical information of the electric field information, the wireless communication device 20 can collect a large amount of electric field information of the downlink signal affected by various conditions, so that the transmission power of the wireless communication can be obtained more accurately. It will be possible to decide. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

Next, an operation example of the wireless communication device 20 of the present embodiment will be described with reference to FIG.

First, the arrival direction estimation unit 235 estimates the arrival direction of the uplink signal of the terminal 60 based on the intermediate processing received RF signal and the combined received RF signal. Then, the estimated arrival direction is stored in the arrival direction storage unit 252 together with the terminal ID and the time information (step S101 in FIG. 2).

Further, the electric field information receiving unit 256 stores the electric field information measured by the terminal in the electric field information storage unit 253 together with the terminal ID and the time information (step S102).

Then, the transmission power determination unit 25 determines the transmission power of wireless communication based on the statistical information of the arrival direction and the electric field information (step S103).

Next, a more specific operation example of step S103 will be described with reference to FIGS. 8 to 11.

8 to 10 are examples of statistical processing operations performed by the statistical information processing unit 254. The statistical information processing unit 254 first determines whether each terminal 60 is a low electric field terminal or a high interference terminal. Then, the maximum transmission power in each direction is determined based on the determination result of the low electric field terminal / high interference terminal.

A low electric field terminal is a terminal that exists in a low electric field area, for example, a coverage hole (FIG. 12). Further, the high-interference terminal is a terminal existing in a high-interference area (FIG. 13) where inter-cell interference is high.

First, the statistical information processing unit 254 sets an initial value for the terminal ID to be processed (step S201 in FIG. 8). Next, it is confirmed whether or not the electric field information corresponding to the terminal ID to be processed exists in the electric field information storage unit 253. Then, if the electric field information is present (YES in step S202), it is determined in steps S203 to S209 whether the terminal is a low electric field terminal or a high interference terminal.

Steps S203 to S206 are examples of determination operations of the low electric field terminal. In this embodiment, it is determined whether the terminal is a low electric field terminal based on RSRP.

First, the statistical information processing unit 254 acquires RSRP in a predetermined period corresponding to the terminal ID to be processed from the electric field information storage unit 253 (step S203). Next, the maximum RSRP (maximum RSRP value) and the minimum RSRP (minimum RSRP value) are extracted from the acquired RSRP information, and the difference between the maximum RSRP and the minimum RSRP is calculated. When the difference between the maximum RSRP and the minimum RSRP is less than the predetermined threshold value Th_v (YES in step S204), the average RSRP (mean value of RSRP values) and the predetermined minimum RSRP threshold value Th_Plow are compared. Then, when the average RSRP is less than the minimum RSRP threshold value Th_Plow (YES in step S205), it is determined that the terminal is a low electric field terminal (step S206).

By doing so, the statistical information processing unit 254 can determine a terminal having a small fluctuation in the electric field strength RSRP and a small RSRP as a low electric field terminal.

If the terminal 60 is not determined to be a low electric field terminal (NO in step S205), the statistical information processing unit 254 determines whether the terminal is a high interference terminal. Steps S207 to S209 are examples of the determination operation of the high interference terminal. In this embodiment, it is determined whether the terminal is a high interference terminal based on CQI and RSRP.

First, the statistical information processing unit 254 acquires the CQI from the electric field information storage unit 253 (step S207). Next, the statistical information processing unit 254 determines whether the average value of CQI (mean CQI) is less than the predetermined minimum CQI threshold value Th_i and the average RSRP is larger than the predetermined maximum RSRP threshold value Th_Phy. Then, when the determination result is true (YES in step S208), it is determined that the terminal is a high interference terminal (step S209).

By doing so, the statistical information processing unit 254 can determine a terminal having an electric field strength RSRP to some extent and having a small (poor) radio wave quality CQI as a high interference terminal.

Then, if the terminal ID to be processed is not the final value (NO in step S210), the statistical information processing unit 254 executes step S202 after changing the terminal ID to be processed (step S211). If the terminal ID is the final value (YES in step S210), the statistical information processing unit 254 implements step S212 in FIG.

Next, the statistical information processing unit 254 classifies each low electric field terminal / high interference terminal into a predetermined direction (θ) based on the terminal ID determined to be the low electric field terminal / high interference terminal in FIG. 8 and the arrival direction. Then, the number of low electric field terminals / the number of high interference terminals for each direction is calculated. In the present embodiment, the statistical information processing unit 254 classifies each terminal into one of eight directions based on the arrival direction. FIG. 14 shows an example of the calculation result of the number of low electric field terminals / the number of high interference terminals.

Then, the statistical information processing unit 254 sorts each direction in descending order of the number of low electric field terminals (step S212 in FIG. 9). FIG. 15 shows an example of the sorting result.

Next, the statistical information processing unit 254 confirms that there is a sufficient bias in the direction in which there are many low electric field terminals and that the number of low electric field terminals is sufficient. This makes it possible to improve the estimation accuracy of the direction of the low electric field. For example, the statistical information processing unit 254 has an average value of the number of low electric field terminals for α% of the upper direction and α% of the lower direction (α is a predetermined number) among the directions of the classification destination. Is calculated. Then, the difference between the upper average value and the lower average value and the threshold value Th are compared, and if the difference is equal to or higher than the threshold value Th, there is sufficient bias in the direction in which there are many low electric field terminals and the value is low. It is determined that the number of electric field terminals is sufficient.

When the difference between the upper average value and the lower average value is the threshold value Th or more (YES in step S213), the statistical information processing unit 254 sets the direction in which the number of low electric field terminals is higher β (β is a predetermined number). ) Select (step S214). Then, the maximum transmission power P_max (θ) is increased by 1 step (1 step is a predetermined value) for the direction selected in step S214 (step S215).

Next, the statistical information processing unit 254 also performs statistical processing on the high interference terminal in the same manner as the low electric field terminal.

First, the statistical information processing unit 254 sorts each direction in descending order of the number of high-interference terminals (step S216 in FIG. 10).

Next, the statistical information processing unit 254 confirms that there is a sufficient bias in the direction in which there are many high-interference terminals and that the number of high-interference terminals is sufficient. This makes it possible to improve the estimation accuracy of the direction of high interference. For example, the statistical information processing unit 254 has an average value of the number of high-interference terminals for α% of the high-interference terminals and α% of the low-order directions (α is a predetermined number) among the directions of the classification destination. Is calculated. Then, the difference between the upper average value and the lower average value and the threshold value Th are compared, and if the difference is equal to or higher than the threshold value Th, the detection direction of high interference is sufficiently biased and high interference occurs. It is determined that the number of terminals is sufficient.

When the difference between the upper average value and the lower average value is equal to or greater than the threshold value Th (YES in step S217), the statistical information processing unit 254 sets the direction in which the number of high interference terminals is higher to γ (γ is a predetermined number). ) Select (step S218). Then, the maximum transmission power P_max (θ) is reduced by 1 step (1 step is a predetermined value) for the direction selected in step S218 (step S219).

FIG. 11 is an operation example of the transmission direction / power determination unit 255. The transmission direction / power determination unit 255 determines the transmission power P (θ) based on the maximum transmission power P_max (θ) determined by the statistical information processing unit 254 and the arrival direction estimated by the arrival direction estimation unit 235.

First, the transmission direction / power determination unit 255 calculates the phase ω and amplitude d of the transmission radio wave and the transmission power P_calc (θ) with respect to the direction θ based on the arrival direction of the terminal 60 (step S301, step S302). .. In steps S301 and S302, a general method for determining the transmission power of the directional beam can be used.

Next, the transmission direction / power determination unit 255 compares the maximum transmission power P_max (θ) with the P_calc (θ) calculated in step S302. Then, when P_max (θ) is P_calc (θ) or less (NO in step S303), the amplitude d is lowered by a predetermined step, and step S301 is performed. When P_max (θ) is larger than P_calc (θ) (YES in step S303), the transmission power P (θ) with respect to the direction θ is set to P_calc (θ) (step S304).

As a result, the transmission direction / power determination unit 255 can control the transmission power so as to be lower than the maximum transmission power determined by the statistical information processing unit 254.

Next, the transmission weight calculation unit 275 calculates the transmission weight based on the transmission power P (θ) determined by the transmission direction / power determination unit 255 and the arrival direction of the uplink signal of each terminal 60. Then, the multiplier 272 multiplies the transmission RF signal for intermediate processing by the transmission weight, the amplifier 271 amplifies the transmission RF signal for intermediate processing multiplied by the transmission weight, and the antenna 21 transmits the transmission RF signal.

As described above, the wireless communication device 20 of the present embodiment determines the low electric field terminal and the high interference terminal based on the electric field information measured by the terminal 60, and determines the arrival direction of the uplink signal and the number of low electric field terminals / high interference terminal. Estimate the direction of low electric field and the direction of high interference based on the number. Then, the maximum transmission power in the direction of the low electric field is increased, and the maximum transmission power in the direction of the high interference terminal is decreased.

16 and 17 show an example of changes in the own cell of the wireless communication device 20 before and after the execution of the transmission power control of the present embodiment. FIG. 16 is an example of the own cell before the transmission power control is executed, and FIG. 17 is an example of the own cell after the transmission power control is executed. As described above, the wireless communication device 20 of the present embodiment can narrow the cell in the high interference direction and widen the cell in the low electric field direction.

Next, operation examples of the above-mentioned statistical information processing unit 254 and transmission direction / power determination unit 255 will be described with reference to specific examples.

In this embodiment, for the sake of simplicity, the direction θ is assumed to be 8 directions. Further, it is assumed that there are three types of electric field strength RSRP: low electric field (-120 dBm) / medium electric field (-100 dBm) / high electric field (-80 dBm) (FIG. 18). Further, it is assumed that there are three types of radio wave quality CQI, 1 (bad) to 3 (good).

Further, the wireless communication device 20 receives electric field information from the terminal 60 every second, and calculates the maximum transmission power (operations of FIGS. 8 to 10) every minute.

FIG. 19 shows an example of the number of terminals 60 for each combination of each direction and each electric field strength in a certain statistical period (1 minute in the case of this embodiment). The value in parentheses after the number of units is the average CQI value.

With the electric field information of FIG. 19 obtained, the wireless communication device 20 performs the operations of FIGS. 8 to 10. The parameters in FIGS. 8 to 10 are Th_v = 40, Th_Plow = −110 dBm, Th_i = 2, Th_Phy = −90 dBm, α = 25, Th = 1, β = 2, γ = 2, 1 step = 5 dB. Suppose there is.

At this time, as a result of steps S203 to S206, the statistical information processing unit 254 determines that the terminal 60 having an RSRP of −120 dBm is a low electric field terminal. Further, as a result of steps S207 to S209, the statistical information processing unit 254 determines that the terminal 60 having a CQI of 1 among the terminals 60 having an RSRP of −100 dBm or −80 dBm is a high interference terminal. The result is shown in FIG.

Then, when the statistical information processing unit 254 sorts the results of FIG. 20 in steps S212 and S216, the results of FIG. 21 are obtained. Since α (= 25)% of the number of directions (= 8) is 2 in step S213 and step S217, the statistical information processing unit 254 has the number of terminals in the upper two directions and the lower two directions. The difference between the two and the threshold Th are compared. At this time, the difference in the number of terminals is 2 for both the low electric field terminal and the high interference terminal, which is larger than the threshold value Th (= 1) (YES in step S213 and step S217). Therefore, in step S214, the statistical information processing unit 254 selects β (= 2) directions in which the number of low electric field terminals is higher. Further, in step S218, γ (= 2) directions having a higher number of high-interference terminals are selected. The orientation selected here is the orientation shown in bold in FIG.

In step S215, the statistical information processing unit 254 increases the maximum transmission power in the direction selected in step S214 by 1 step (= 5 dB). Further, in step S219, the maximum transmission power in the direction selected in step S218 is reduced by 1 step. The result is shown in FIG. The maximum transmission power is decreased by 5 dB for the directions θ1 and the direction θ4 determined to be high interference, and the maximum transmission power is increased by 5 dB for the directions θ5 and the direction θ8 determined to be low electric fields.

FIG. 23 shows an example of the transmission area after the transmission power control is performed by the transmission direction / power determination unit 255 with respect to the result of FIG. 22. Compared with FIG. 18, the area of the direction θ1 and the direction θ4 is narrower, and the area of the direction θ5 and the direction θ8 is wider.

By operating in this way, the wireless communication device 20 determines the transmission power of wireless communication based on the statistical information of the electric field information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. .. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

As described above, in the second embodiment of the present invention, the wireless communication device 20 is based on the statistical information of the electric field information of the downlink signal measured by the terminal and the direction of arrival of the uplink signal from the terminal. , Determine the transmission power of wireless communication. The electric field information of the downlink signal is the information measured by a general terminal. Further, by using the electric field information measured by the terminal, the wireless communication device 20 can more accurately transmit the transmission power of the wireless communication based on the actual electric field information in the terminal for the downlink signal affected by fading or the like. It will be possible to decide. Further, by using the statistical information of the electric field information, the wireless communication device 20 can collect a large amount of electric field information of the downlink signal affected by various conditions, so that the transmission power of the wireless communication can be obtained more accurately. It will be possible to decide. Therefore, it becomes possible to improve the wireless communication quality by optimizing the cells of the wireless base station in an easier and more accurate method.

Further, the statistical information processing unit 254 of the present embodiment confirms that there is a sufficient bias in the direction in which there are many low electric field terminals / high interference terminals, and that the number of low electric field terminals / high interference terminals is sufficient. This makes it possible to further improve the estimation accuracy of the low electric field / high interference direction.

[Hardware configuration example]
An example of a configuration of hardware resources for realizing the wireless communication device (10, 20) in each embodiment of the present invention described above by using one information processing device (computer) will be described. The wireless communication device may be realized by using at least two information processing devices physically or functionally. Further, the wireless communication device may be realized as a dedicated device. Further, only a part of the functions of the wireless communication device may be realized by using the information processing device.

FIG. 24 is a diagram schematically showing a hardware configuration example of an information processing device capable of realizing the wireless communication device of each embodiment of the present invention. The information processing device 90 includes a communication interface 91, an input / output interface 92, an arithmetic unit 93, a storage device 94, a non-volatile storage device 95, and a drive device 96.

The communication interface 91 is a communication means for the wireless communication device of each embodiment to communicate with an external device by wire or / and wirelessly. When the wireless communication device is realized by using at least two information processing devices, the devices may be connected so as to be able to communicate with each other via the communication interface 91.

The input / output interface 92 is a man-machine interface such as a keyboard as an example of an input device and a display as an output device.

The arithmetic unit 93 is an arithmetic processing unit such as a general-purpose CPU (Central Processing Unit) or a microprocessor. The arithmetic unit 93 can, for example, read various programs stored in the non-volatile storage device 95 into the storage device 94 and execute processing according to the read programs.

The storage device 94 is a memory device such as a RAM (Random Access Memory) that can be referred to by the arithmetic unit 93, and stores programs, various data, and the like. The storage device 94 may be a volatile memory device.

The non-volatile storage device 95 is, for example, a non-volatile storage device such as a ROM (Read Only Memory), a flash memory, etc., and can store various programs, data, and the like.

The drive device 96 is, for example, a device that processes data reading and writing to a recording medium 97, which will be described later.

The recording medium 97 is an arbitrary recording medium capable of recording data, such as an optical disk, a magneto-optical disk, or a semiconductor flash memory.

In each embodiment of the present invention, for example, a wireless communication device is configured by the information processing device 90 illustrated in FIG. 24, and a program capable of realizing the functions described in each of the above embodiments is supplied to the wireless communication device. It may be realized by doing.

In this case, the embodiment can be realized by the arithmetic unit 93 executing the program supplied to the wireless communication device. It is also possible to configure some functions of the information processing device 90, not all of the wireless communication devices.

Further, the program may be recorded in the recording medium 97, and the program may be appropriately stored in the non-volatile storage device 95 at the shipping stage, the operation stage, or the like of the wireless communication device. In this case, as the supply method of the above program, a method of installing the program in the wireless communication device by using an appropriate jig may be adopted at the manufacturing stage before shipment, the operation stage, or the like. Further, as the method of supplying the above program, a general procedure such as a method of downloading from the outside via a communication line such as the Internet may be adopted.

It should be noted that each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the gist of the present invention.

Some or all of the above embodiments may also be described, but not limited to:

(Appendix 1)
The wireless communication unit that communicates wirelessly with the terminal,
An azimuth estimation unit that estimates the direction of arrival of the uplink signal from the terminal, and
An electric field information receiving unit that receives electric field information of a downlink signal measured by the terminal from the terminal.
A wireless communication device including a transmission power determination unit that determines a transmission power of the wireless communication based on the statistical information of the electric field information and the arrival direction.

(Appendix 2)
The wireless communication device according to Appendix 1, wherein the transmission power determination unit determines the transmission power for each direction.

(Appendix 3)
The transmission power determination unit estimates whether each of the terminals exists in the low electric field area based on the electric field information, and determines the number of low electric field terminals existing in the low electric field area and the uplink signal of the low electric field terminal. The wireless communication device according to Appendix 2, wherein the direction for increasing the transmission power is determined based on the arrival direction.

(Appendix 4)
The transmission power determination unit estimates whether or not each of the terminals exists in the high interference area where the interference between cells is high based on the electric field information, and the number of high interference terminals existing in the high interference area and the high interference terminal. The wireless communication device according to Supplementary Note 2 or 3, wherein the direction for reducing the transmission power is determined based on the arrival direction of the uplink signal of the above.

(Appendix 5)
The radio according to Appendix 4, wherein the transmission power determination unit estimates that the terminal whose electric field strength is higher than a predetermined value and whose radio wave quality is lower than a predetermined value is the high interference terminal. Communication device.

(Appendix 6)
The wireless communication device according to any one of Supplementary note 1 to Supplementary note 5, wherein the transmission power determination unit determines the maximum value of the transmission power.

(Appendix 7)
The electric field information is characterized by including one or more of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), and CQI (Channel Quality Indicator). The wireless communication device according to any one of Supplementary note 1 to Supplementary note 6.

(Appendix 8)
The wireless communication device according to any one of Supplementary note 1 to Supplementary note 7, and
A wireless communication system including the terminal.

(Appendix 9)
Wirelessly communicate with the terminal
Estimate the direction of arrival of the uplink signal from the terminal,
The electric field information of the downlink signal measured by the terminal is received from the terminal, and the electric field information is received from the terminal.
A wireless communication method, characterized in that the transmission power of the wireless communication is determined based on the statistical information of the electric field information and the arrival direction.

(Appendix 10)
The wireless communication method according to Appendix 9, wherein the transmission power for each direction is determined.

(Appendix 11)
Based on the electric field information, it is estimated whether each of the terminals exists in the low electric field area, and the number of low electric field terminals existing in the low electric field area and the arrival direction of the uplink signal of the low electric field terminal are used. The wireless communication method according to Appendix 10, wherein the orientation for increasing the transmission power is determined.

(Appendix 12)
Based on the electric field information, it is estimated whether each of the terminals exists in the high interference area where the inter-cell interference is high, the number of the high interference terminals existing in the high interference area, and the arrival of the uplink signal of the high interference terminal. The wireless communication method according to Appendix 10 or Appendix 11, wherein the orientation for reducing the transmission power is determined based on the orientation.

(Appendix 13)
The wireless communication method according to Appendix 12, wherein the terminal having an electric field strength higher than a predetermined value and a radio wave quality lower than a predetermined value is estimated to be the high interference terminal.

(Appendix 14)
The wireless communication method according to any one of Supplementary note 9 to Supplementary note 13, characterized in that the maximum value of the transmission power is determined.

(Appendix 15)
The electric field information is characterized by including one or more of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), and CQI (Channel Quality Indicator). The wireless communication method according to any one of Supplementary note 9 to Supplementary note 14.

(Appendix 16)
On the computer
A wireless communication function that communicates wirelessly with the terminal,
An azimuth estimation function that estimates the direction of arrival of the uplink signal from the terminal, and
The electric field information receiving function that receives the electric field information of the downlink signal measured by the terminal from the terminal,
A wireless communication program characterized by realizing a transmission power determination function for determining a transmission power of the wireless communication based on the statistical information of the electric field information and the arrival direction.

(Appendix 17)
The wireless communication program according to Appendix 16, wherein the transmission power determination function determines the transmission power for each direction.

(Appendix 18)
The transmission power determination function estimates whether each of the terminals exists in the low electric field area based on the electric field information, and the number of low electric field terminals existing in the low electric field area and the uplink signal of the low electric field terminal. The wireless communication program according to Appendix 17, wherein the direction for increasing the transmission power is determined based on the arrival direction.

(Appendix 19)
The transmission power determination function estimates whether each of the terminals exists in a high interference area where cell-to-cell interference is high based on the electric field information, and the number of high interference terminals existing in the high interference area and the high interference terminal. 17. The wireless communication program according to Supplementary Note 17 or 18, wherein the direction for reducing the transmission power is determined based on the arrival direction of the uplink signal of the above.

(Appendix 20)
The radio according to Appendix 19, wherein the transmission power determination function estimates that the terminal whose electric field strength is higher than a predetermined value and whose radio wave quality is lower than a predetermined value is the high interference terminal. Communication program.

(Appendix 21)
The wireless communication program according to any one of Supplementary note 16 to Supplementary note 20, wherein the transmission power determination function determines the maximum value of the transmission power.

(Appendix 22)
The electric field information is characterized by including one or more of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), and CQI (Channel Quality Indicator). The wireless communication program according to any one of Supplementary note 16 to Supplementary note 21.

10, 20 wireless communication device 11 wireless communication unit 12 arrival direction estimation unit 13 electric field information reception unit 14 transmission power determination unit 21 antenna 22 switch 23 reception signal processing unit 24 demodulation / decoding unit 25 transmission power determination unit 26 coding / modulation unit 27 Transmission signal processing unit 60 Terminal 90 Information processing device 91 Communication interface 92 Input / output interface 93 Computing device 94 Storage device 95 Non-volatile storage device 96 Drive device 97 Recording medium

Claims (10)

The wireless communication unit that communicates wirelessly with the terminal,
An azimuth estimation unit that estimates the direction of arrival of the uplink signal from the terminal, and
An electric field information receiving unit that receives electric field information of a downlink signal measured by the terminal from the terminal.
With a transmission power determination unit that determines the transmission power for each direction of the wireless communication based on the statistical information of the electric field information and the arrival direction.
Equipped with
The transmission power determination unit estimates whether each of the terminals exists in the low electric field area based on the electric field information, and determines the number of low electric field terminals existing in the low electric field area and the uplink signal of the low electric field terminal. A wireless communication device, characterized in that the direction in which the transmission power is increased is determined based on the arrival direction. The wireless communication unit that communicates wirelessly with the terminal,
An azimuth estimation unit that estimates the direction of arrival of the uplink signal from the terminal, and
An electric field information receiving unit that receives electric field information of a downlink signal measured by the terminal from the terminal.
With a transmission power determination unit that determines the transmission power for each direction of the wireless communication based on the statistical information of the electric field information and the arrival direction.
Equipped with
The transmission power determination unit estimates whether or not each of the terminals exists in the high interference area where the interference between cells is high based on the electric field information, and the number of high interference terminals existing in the high interference area and the high interference terminal. A wireless communication device, characterized in that the direction for reducing the transmission power is determined based on the direction of arrival of the uplink signal. The transmission power determination unit estimates whether each of the terminals exists in the low electric field area based on the electric field information, and determines the number of low electric field terminals existing in the low electric field area and the uplink signal of the low electric field terminal. The orientation that increases the transmission power is determined based on the arrival orientation.
The wireless communication device according to claim 2. 2 . 3. The wireless communication device according to 3. The electric field information is characterized by including one or more of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), and CQI (Channel Quality Indicator). The wireless communication device according to any one of claims 1 to 4 . The wireless communication device according to any one of claims 1 to 5 .
A wireless communication system including the terminal. Wirelessly communicate with the terminal
Estimate the direction of arrival of the uplink signal from the terminal,
The electric field information of the downlink signal measured by the terminal is received from the terminal, and the electric field information is received from the terminal.
Based on the statistical information of the electric field information and the arrival direction, the transmission power for each direction of the wireless communication is determined .
Based on the electric field information, it is estimated whether each of the terminals exists in the low electric field area, and the number of low electric field terminals existing in the low electric field area and the arrival direction of the uplink signal of the low electric field terminal are used. A wireless communication method comprising determining the orientation for increasing transmission power . Wirelessly communicate with the terminal
Estimate the direction of arrival of the uplink signal from the terminal,
The electric field information of the downlink signal measured by the terminal is received from the terminal, and the electric field information is received from the terminal.
Based on the statistical information of the electric field information and the arrival direction, the transmission power for each direction of the wireless communication is determined.
Based on the electric field information, it is estimated whether each of the terminals exists in the high interference area where the inter-cell interference is high, the number of the high interference terminals existing in the high interference area, and the arrival of the uplink signal of the high interference terminal. Determine the orientation that reduces the transmit power based on the orientation
A wireless communication method characterized by that. On the computer
A wireless communication function that communicates wirelessly with the terminal,
An azimuth estimation function that estimates the direction of arrival of the uplink signal from the terminal, and
The electric field information receiving function that receives the electric field information of the downlink signal measured by the terminal from the terminal,
Based on the statistical information of the electric field information and the arrival direction, a transmission power determination function for determining the transmission power for each direction of the wireless communication is realized .
The transmission power determination function estimates whether each of the terminals exists in the low electric field area based on the electric field information, and the number of low electric field terminals existing in the low electric field area and the uplink signal of the low electric field terminal. The orientation that increases the transmission power is determined based on the arrival orientation.
A wireless communication program characterized by that. On the computer
A wireless communication function that communicates wirelessly with the terminal,
An azimuth estimation function that estimates the direction of arrival of the uplink signal from the terminal, and
The electric field information receiving function that receives the electric field information of the downlink signal measured by the terminal from the terminal,
With a transmission power determination function that determines the transmission power for each direction of the wireless communication based on the statistical information of the electric field information and the arrival direction.
Realized,
The transmission power determination function estimates whether each of the terminals exists in a high interference area where cell-to-cell interference is high based on the electric field information, and the number of high interference terminals existing in the high interference area and the high interference terminal. The direction in which the transmission power is reduced is determined based on the arrival direction of the uplink signal of the above.
A wireless communication program characterized by that.

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