JP6815357B2 - Base station equipment that boosts transmission power in wireless communication systems that use repetitive transmission, its control method, and programs. - Google Patents

Description

The present invention relates to a resource utilization technique in a wireless communication system in which repeated transmission is used.

The 3rd Generation Partnership Project (3GPP) aims at communication with low power consumption and a wide communication area, and expands the coverage area by repeatedly transmitting (Repetition) signals of each channel CE mode (Coverage Enhancement mode). Has been introduced (see Non-Patent Document 1).

3GPP TS36.211 V13.2.0, June 2016

In the repeated transmission of a signal, the number of radio resources used increases as the number of repeated transmissions increases. On the other hand, when the communication is performed by the half-duplex method in which the downlink communication and the uplink communication are time-switched and executed, the number of repetitive transmissions that can be used in the communication is limited. Therefore, for at least a part of the signals, the number of repeated transmissions can be suppressed, or sufficient radio quality can be obtained with a limited number of repeated transmissions, and a sufficient number of repeated transmissions of other signals can be secured as needed. Is important.

The present invention has been made in view of such a problem, and provides a technique for appropriately using resources in a communication system in which signals are repeatedly transmitted.

The base station apparatus according to one aspect of the present invention is the base station apparatus in a wireless communication system capable of executing communication with a predetermined radio quality by repeatedly transmitting signals between the base station apparatus and the terminal apparatus. The control means has a communication means for wirelessly communicating with the terminal device and a control means for controlling the communication means, and the control means has a predetermined signal having no information in amplitude in the signal transmitted to the terminal device. The transmission power of the signal transmitted to the terminal device and the number of repeated transmissions of the signal transmitted to the terminal device are determined based on at least whether or not the signal is modulated by the modulation method, and the determined transmission power and the repeated transmission are determined. It is characterized in that the communication means is controlled so as to transmit a signal to the terminal device by using the number of times.

According to the present invention, resources can be appropriately used in a communication system in which signals are repeatedly transmitted.

It is a figure which shows the configuration example of a wireless communication system. It is a figure which outlines the boost of transmission power and repetitive transmission. It is a figure which explains roughly the method of determining the boost amount of transmission power. It is a figure which shows the hardware configuration example of a base station apparatus. It is a figure which shows the functional configuration example of a base station apparatus. It is a figure which shows the example of the flow of processing executed by a base station apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(System configuration)
FIG. 1 shows a configuration example of the wireless communication system according to the present embodiment. In one example, the wireless communication system includes a base station device 101 and a terminal device 102. Note that FIG. 1 shows an example including one base station device 101 and one terminal device 102 for the sake of simplicity, but the wireless communication system has a large number of devices like a normal cellular communication system. It may include a base station device 101 and a number of terminal devices 102.

It is assumed that this wireless communication system can at least use MTC (Machine Type Communication) defined by 3GPP, and can execute communication with extended coverage by using the above-mentioned CE mode. That is, this wireless communication system uses the frequency band for MTC (frequency band for 6 resource blocks) and repeatedly transmits signals between the base station device 101 and the terminal device 102 to obtain a predetermined wireless quality. (For example, SIR (signal to interference power ratio) = 3 dB) is configured to enable communication. The repeated transmission here refers to the Repetition defined in 3GPP, but other repeated transmission techniques may be used. In the following, communication by MTC is performed in this wireless communication system, but communication may be performed by any other system capable of providing wide coverage with low power.

Further, the terminal device 102 adopts a half-duplex method, and communicates on the downlink (wireless link in the direction from the base station device 101 to the terminal device 102) and the uplink (wireless in the direction from the terminal device 102 to the base station device 101). Communication by (link) is switched in time and executed. That is, when communicating on the downlink, communication on the uplink is not performed, and when communicating on the uplink, communication on the downlink is not performed. When the half-duplex method is used in the communication in the CE mode, the number of repetitions in the repeated transmission of the signal is limited as described above. If the downlink communication is repeated many times, the period for the uplink communication cannot be secured, and if the uplink communication is repeated many times, the downlink communication is performed. This is because the period cannot be secured.

Therefore, in the present embodiment, the base station device 101 reduces the number of repeated transmissions of at least a part of the signals by boosting the transmission power of at least a part of the signals transmitted to the terminal device 102. For example, the base station device 101 doubles the transmission power and halves the number of repeated transmissions. According to this, since the resource (time resource) required for downlink communication can be reduced, the reduced amount can be allocated to uplink communication. Further, for example, the base station apparatus 101 doubles the received SIR in the terminal apparatus 102 (improves by 3 dB) by boosting the transmission power four times while halving the number of repeated transmissions. Can be done. At this time, by doubling the number of repeated transmissions from the terminal device 102 to the base station device 101, the received SIR in the base station device 101 can be doubled.

2 (A) and 2 (B) show examples of a case where the downlink transmission power is not boosted and a case where the downlink transmission power is boosted, respectively. FIG. 2A shows an example in which the downlink control channel (MPDCCH, MTC Physical Downlink Control Channel) and the downlink shared channel (PDSCH, Physical Downlink Sharp Channel) are repeated 4 times and 8 times, respectively. ing. FIG. 2B shows an example in which the transmission power of these downlink signals is boosted four times. Further, in FIG. 2B, the number of repeated transmissions of MPDCCH is reduced to 2 and the number of repeated transmissions of PDSCH is reduced to 4. In this case, since the number of repeated transmissions is halved, the gain is reduced by 3 dB, but a gain of 6 dB can be obtained by boosting the transmission power, and a total gain of 3 dB can be obtained. Further, FIG. 2A shows an example in which the number of repetitions between the uplink control channel (PUCCH, Physical Uplink Control Channel) and the uplink shared channel (PUSCH, Physical Uplink Sharp Channel) is two times each. .. On the other hand, as shown in FIG. 2B, as a result of being able to reduce the number of repeated transmissions on the downlink, the number of repeated transmissions of the uplink signal can be increased, for example, twice. According to this, both PUCCH and PUSCH can obtain a gain of 3 dB. In this way, by boosting the power of the downlink signal from the state of FIG. 2 (A) as shown in FIG. 2 (B), a gain can be obtained not only in the downlink but also in the uplink.

On the other hand, in the downlink, the terminal device 102 transmits a predetermined signal having a constant power determined between the base station device 101 and the terminal device 102 prior to communication, such as a reference signal transmitted from the base station device 101. By measuring, wireless quality measurement and cell search are performed. Therefore, the transmission power should not be boosted for the predetermined signals used for these measurements and the like. On the other hand, if the transmission power of the reference signal is not boosted, the terminal device 102 may not be able to accurately estimate the channel with respect to the amplitude, and may not be able to demodulate the signal modulated by the modulation method having information on the amplitude.

Therefore, in the present embodiment, the base station apparatus 101 boosts the transmitted signal based on at least whether or not the signal transmitted to the terminal apparatus 102 is modulated by a predetermined modulation method having no information on the amplitude. Decide whether or not. For example, the base station apparatus 101 is a signal modulated by a modulation method having no information in amplitude, such as PSK (Binary PSK (Phase Shift Keying)) or QPSK (Quadrature PSK) or FSK (Frequency Shift Keying). Is decided to boost the transmission power. On the other hand, the base station apparatus 101 does not boost the transmission power for a signal modulated by a modulation method having information on the amplitude, such as 16QAM (Quadrature Amplitude Modulation) or ASK (Amplitude Shift Keying). Even when the transmission power is boosted, the base station apparatus 101 may not boost a predetermined signal such as a reference signal. That is, a predetermined signal such as a reference signal is transmitted with a predetermined first transmission power determined between the base station device 101 and the terminal device 102 prior to communication, and other data signals (control data / Only the user data) may be transmitted at a power higher than a predetermined second transmission power defined between the base station device 101 and the terminal device 102 prior to the communication. The first transmission power may be set to a higher power than, for example, the second transmission power in order to accurately perform measurement or cell search, for example. Then, by boosting the transmission power of the data signal, the data signal can be transmitted with a transmission power higher than that of the first transmission power. However, the transmission power after boosting may also be lower than the first transmission power. On the other hand, when the data signal is not boosted, the data signal is transmitted with the above-mentioned second transmission power. In any of these cases, since the first transmission power is constant, the terminal device 102 can accurately perform measurement, cell search, and the like. On the other hand, since the transmission power of the data signal is boosted, the power relationship between the reference signal and the data signal is different from the usual one, so that the channel estimation regarding the amplitude is inaccurate. However, by boosting the transmission power of the data signal on condition that the modulation is performed by a modulation method having no information on the amplitude, it is possible to obtain a gain regarding the reception quality of the data signal in the terminal device 102.

The base station apparatus 101 also determines the number of times the data signal is repeatedly transmitted, depending on whether or not the transmission power of the data signal is boosted. The number of times of repeated transmission is determined, for example, as the number of times that the signal transmitted to the terminal device 102 can obtain the required predetermined radio quality. For example, in the case of transmission with the above-mentioned second transmission power, when the number of repeated transmissions is 4 and a predetermined radio quality can be obtained, and the transmission power is boosted 4 times, the number of repeated transmissions is 1. Determined once (ie no more repeated transmissions). Similarly, when the transmission power is boosted twice when the predetermined radio quality can be obtained with the number of repeated transmissions being 8 when the transmission is performed with the above-mentioned second transmission power, the number of repeated transmissions is increased. It will be decided 4 times. The amount of the transmission power boost may be different for each repeated transmission. In that case, the cumulative gain obtained by the transmission power boost and the repeated transmission is set to a value at which a predetermined radio quality can be obtained. , The boost amount of transmission power and the number of repeated transmissions can be determined.

Further, the base station apparatus 101 uses the boost amount for the total amount of electric power that the apparatus can use for signal transmission and for signal transmission in a system other than MTC (for example, a conventional LTE (Long Term Evolution) system). It can be determined based on the power expected to be used by the own device. For example, the base station apparatus 101 uses MTC to determine the difference between the total amount of power that can be used for signal transmission and the power that is planned to be used for signal transmission in other systems such as LTE. The boost amount can be determined as the transmit power that can be used for signal transmission so that the MTC signal is transmitted with the available transmit power. Further, the base station apparatus 101 uses, for example, an MTC from a value obtained by subtracting a value obtained by multiplying the planned power used by a predetermined multiplier from the total amount of available power or a value obtained by subtracting a predetermined margin in addition to the planned power used. The transmission power that can be used for signal transmission in the above may be determined, and the boost amount may be determined.

The base station apparatus 101 can specify, for example, the power to be used in LTE according to the number of frequency resources allocated for signal transmission in LTE in a certain subframe. This situation is shown in FIG. Note that FIG. 3 is simplified for the sake of explanation. In reality, MTC uses frequency resources for 6 resources, and LTE uses a large number of frequency resources. Here, the frequency resources that can be used by MTC are used. Is indicated by one side of one rectangle. Therefore, in the following description, the degree of frequency resource usage is described by the number of unused resources, but this does not necessarily correspond to one resource block. At the timing shown in (1) of FIG. 3, there are four free frequency resources that are not scheduled to be used among the frequency resources for LTE. Therefore, the transmission signal in MTC can be boosted up to 5 times. Here, when the target predetermined radio quality is obtained by eight repeated transmissions, the base station apparatus 101 boosts the transmission power four times, for example, and compresses the number of repeated transmissions to two times. As a result, the number of repeated transmissions can be reduced, and for example, the reduced amount of time resources can be allocated to increase the number of repeated transmissions of uplink communication.

On the other hand, at the timing shown in (2) of FIG. 3, there is only one free frequency resource that is not scheduled to be used among the frequency resources for LTE. Therefore, the base station apparatus 101 can determine that the transmission power can only be boosted up to twice in this subframe. The base station apparatus 101 can set an estimated value of the boost amount in advance and set the number of repeated transmissions, for example, based on the statistical value regarding the amount of resources used in the past LTE. This statistical value may be acquired for each place, for each time such as a day of the week or time, for each condition such as when there is an event or not. For example, the base station apparatus 101 boosts the transmission power by 4 times when the statistical value that three or more radio resources are not used is obtained at the timings shown in (2) and (3) of FIG. It can be determined in advance that this can be done, and the number of repeated transmissions can be set to 1/4 of the number of times that a predetermined radio quality can be obtained. Then, when the amount of frequency resources actually used in LTE is large at the timing of actually transmitting the signal, the boost amount can be reduced. For example, at the timing shown in (2) of FIG. 3, the base station apparatus 101 is boosted because there is only one resource that is not actually used even if it is planned to be boosted four times based on the statistical value. Double the amount. On the other hand, at the timing shown in (3) of FIG. 3, since there are seven unused resources, the transmission power can be boosted four times as originally planned. Since this is not sufficient to obtain the predetermined radio quality, the base station apparatus 101 increases the boost amount from the initial schedule, for example, at the timing of (3) in FIG. 3 where there are many unused resources. You may. In this way, it is possible to appropriately set the boost amount according to the power usage status in other systems such as LTE.

In the base station device 101, not only the past statistical values but also the accumulated amount of data to be transmitted in other systems such as LTE, the type of data to be transmitted in the accumulated other systems, and the occurrence in other systems. The amount of frequency resources scheduled to be used in LTE may be estimated based on the amount of data scheduled to be performed, and the boost amount and the planned value of the number of repeated transmissions may be determined. For example, when the amount of data to be transmitted is large in LTE, it is considered that the amount of unused frequency resources decreases for a certain period of time. Therefore, the base station apparatus 101 can determine that the transmission power cannot be boosted or the boost amount should be reduced to secure a large number of repeated transmissions during that period. Also, for example, the amount of unused frequency resources is estimated according to whether the data to be transmitted in LTE is required to be real-time and should be transmitted immediately, and the boost amount and the number of repeated transmissions are planned. The value may be determined. For example, data with high real-time characteristics needs to be transmitted within a short period of time, so if a large amount of data with high real-time characteristics is accumulated, it will be used for a certain period of time until they are transmitted. It is believed that the amount of frequency resources that are not used will decrease. Therefore, the base station apparatus 101 can determine that the transmission power cannot be boosted or the boost amount should be reduced to secure a large number of repeated transmissions during that period. On the other hand, even if a large amount of data with low real-time property is accumulated, if the amount of data with high real-time property is small, by delaying the transmission timing of data with low real-time property, a certain amount of frequency is used in LTE. Resources can be prevented from being used. Therefore, when the amount of accumulated data having high real-time performance is small, the base station apparatus 101 can determine that the transmission power of the MTC can be boosted and can compress the number of repeated transmissions. In addition, if there is data to be transmitted, such as VoLTE or streaming, which is not actually stored but is scheduled to occur at regular intervals, it is assumed that wireless resources for transmitting that data will be secured. As a result, it can be determined whether or not the transmission power of the MTC can be boosted. The base station apparatus 101 can determine the boost amount and the number of repeated transmissions by any or a combination of these conditions, but these conditions are only examples, and other conditions may be used. .. The base station apparatus 101 can determine the number of repeated transmissions after determining the planned value of the boost amount as described above. For example, the base station apparatus 101 may decide to transmit a signal with a number of repetitive transmissions of 1/4 of the number required to obtain a predetermined radio quality, for example, when a 4 times boost is possible.

In one example, the base station apparatus 101 determines the boost amount described above when the value related to the amount of radio resources used in the MTC (for example, the usage rate or usage amount of radio resources) exceeds a predetermined value. The number of repeated transmissions may be determined based on the boost. In this case, the base station apparatus 101 prevents the determination of the boost amount and the determination of the number of repeated transmissions based on the boost as described above when the value relating to the amount of radio resources used in the MTC does not exceed a predetermined value. You may. Further, the base station device 101 may determine the boost amount and the number of repeated transmissions based on the boost only when the number of terminal devices 102 communicating by MTC exceeds a predetermined number. This is because if the radio resource usage rate in the MTC is low or expected, it is not necessary to compress the number of repeated transmissions by boosting.

Further, the base station apparatus 101 is based on the above-mentioned determination of the boost amount and the boost when the predetermined radio quality cannot be satisfied even by the predetermined number of times of repeated transmission in the uplink or the downlink. The number of repeated transmissions may be determined. For example, in downlink communication, when the base station apparatus 101 cannot satisfy a predetermined radio quality even by repeated transmission of a predetermined number of times (upper limit number of times), the base station apparatus 101 may perform at least a part of the transmission signal. For example, the transmission power can be boosted while maintaining the number of repeated transmissions. As a result, the reception quality is improved by the amount that the transmission power is boosted, and the probability that a predetermined radio quality can be obtained is improved. At this time, if the required number of repeated transmissions can be compressed by boosting the transmission power, the base station apparatus 101 compresses the number of repeated transmissions within a range that can satisfy a predetermined radio quality, for example. You may. Further, when the base station apparatus 101 cannot satisfy the predetermined radio quality even by the predetermined number of repeated transmissions in the uplink communication, the base station device 101 repeatedly boosts the transmission power of the downlink signal. Compress the number of transmissions. Then, the number of repeated transmissions of the uplink signal is increased by using the free radio resource obtained by compressing the number of repeated transmissions. As a result, the reception quality of the uplink signal is improved by the increase in the number of repeated transmissions, and the probability that a predetermined radio quality can be obtained is improved. Even if the transmission power boost is used in communication with a certain terminal device 102, if a predetermined radio quality cannot be obtained (for example, over a certain period of time), even if the communication with the terminal device 102 is stopped. Good. According to this, it is possible to prevent the radio resources from being wasted by the communication in which the predetermined radio quality cannot be obtained even by using the boost of the transmission power.

(Device configuration)
Subsequently, a configuration example of the base station apparatus 101 that executes the above-described processing will be described with reference to FIG. In one example, the base station device 101 includes a processor 401, a ROM 402, a RAM 403, a storage device 404, and a communication circuit 405. The processor 401 is a computer including one or more processing circuits such as a general-purpose CPU (central processing unit) and an ASIC (application specific integrated circuit), and is stored in a ROM 402 or a storage device 404. By reading and executing the program, the entire process of the base station apparatus 101 and each of the above-mentioned processes are executed. The ROM 402 is a read-only memory that stores information such as programs and various parameters related to processing executed by the base station apparatus 101. The RAM 403 is a random access memory that functions as a workspace when the processor 401 executes a program and stores temporary information. The storage device 404 is composed of, for example, a detachable external storage device or the like. The communication circuit 405 is composed of, for example, a circuit for wired communication or wireless communication. The base station device 101 is configured as a communication circuit 405 for communication with the terminal device 102, including, for example, a baseband circuit for each of MTC and LTE, an RF circuit, and an antenna. Further, the communication circuit 405 of the base station apparatus 101 may include, for example, a circuit for performing (wired or wireless) communication with another base station apparatus or a network node. Although one communication circuit 405 is shown in FIG. 4, the base station apparatus 101 may have a plurality of communication circuits.

FIG. 5 shows an example of the functional configuration of the base station apparatus 101. In one example, the base station apparatus 101 includes a communication unit 501 and a communication control unit 502. Further, the communication control unit 502 includes, for example, a determination unit 503, a boost amount determination unit 504, and a repetition number determination unit 505.

The communication unit 501 is a functional unit for communicating with the terminal device 102. The communication control unit 502 controls the communication by the communication unit 501. For example, the communication control unit 502 sets parameters including the presence / absence of boosting of the downlink signal transmission signal, the boost amount, and the number of repeated transmissions, and causes the communication unit 501 to perform communication according to the set parameters. A control signal is input to it.

The determination unit 503 determines whether or not to boost the downlink transmission power and set the number of repeated transmissions as described above (hereinafter, these are collectively referred to as "target processing"). For example, the determination unit 503 determines that the target process is performed when the value related to the amount of radio resources used in the MTC (value corresponding to the usage rate or the usage amount) exceeds a predetermined value. Further, the determination unit 503 may determine that the target processing is performed when the number of terminal devices 102 communicating by MTC exceeds a predetermined number. Further, the determination unit 503 may determine that the target process is performed when the predetermined radio quality cannot be satisfied even by the repeated transmission of the uplink or the downlink a predetermined number of times. Further, when the determination unit 503 determines that the target processing is performed by the above-mentioned various determinations, the determination unit 503 further determines whether the transmission target signal is modulated by a modulation method having no information in the amplitude, and outputs information to the amplitude. When a modulation method that does not have is used, it is determined that the target process is executed. In addition, the determination unit 503 does not boost the transmission power of the signal even if it is determined by the above-mentioned various determinations that the target processing is performed for the signal in which the modulation method having the information in the amplitude is used. To decide. If the communication control unit 502 is not determined to perform the target processing by the above-mentioned various determinations, the communication control unit 502 uses a predetermined power and the number of repeated transmissions determined between the base station device 101 and the terminal device 102 prior to the communication. , The communication unit 501 is controlled so as to transmit a data signal.

The boost amount determination unit 504 and the repetition number determination unit 505 repeat the boost amount of the transmission power so that the terminal device 102 can obtain a predetermined radio quality when the determination unit 503 determines that the above-mentioned target process is executed. Determine the number of transmissions. The boost amount determination unit 504 may determine the boost amount of the transmission power based on, for example, the total amount of power that the base station apparatus 101 can use to transmit the signal and the power that is expected to be used in LTE. Further, the boost amount determination unit 504 is scheduled to be generated in the amount of resources (actual allocation status and statistical value) allocated by the base station device 101 in LTE, the accumulated amount and type of data to be transmitted in LTE, and LTE. The boost amount of the transmission power can be determined based on the amount of data and the like. The repetition number determination unit 505 determines the number of repetitions so that a predetermined radio quality can be obtained, for example, based on the boost amount determined by the boost amount determination unit 504. The number of repetitions determination unit 505 may determine the number of repetitions, and then the boost amount of the transmission power corresponding to the number of repetitions. For example, the repetition count determination unit 505 estimates the possible transmission power boost amount based on the statistical value of the amount of radio resources used in the past LTE, and repeats the number of transmissions according to the estimated value. Can be decided. Then, the boost amount determination unit 504 satisfies a predetermined radio quality within the range of the number of repeated transmissions and according to the difference value between the total amount of available power and the power used in LTE. The amount of boost can be determined. The boost amount may differ for each subframe, and even if the boost amount is insufficient in some subframes among the determined number of repeated transmissions, the boost amount is increased in other subframes. The boost amount may be adjusted so as to satisfy a predetermined radio quality.

(Processing flow)
Subsequently, an example of the processing flow executed by the base station apparatus 101 will be described with reference to FIG. First, the base station apparatus 101 determines whether or not the conditions for executing the boost of the transmission power and the determination of the number of repeated transmissions are satisfied (S601). The base station apparatus 101 may always execute this process, and in that case, the process of S601 may be omitted. In the determination of S601, for example, whether or not the value related to the amount of radio resources used in MTC (value corresponding to the usage rate and usage amount) exceeds a predetermined value, and the number of terminal devices 102 communicating by MTC is a predetermined number. Various conditions such as whether or not it exceeds, and whether or not the predetermined radio quality cannot be satisfied even by repeating transmission a predetermined number of times for each of the uplink and the downlink. Can be done based on. Since the details of this determination are as described above, they will not be repeated here. When the base station apparatus 101 determines that the conditions for executing the boost of the transmission power and the determination of the number of repeated transmissions are satisfied (YES in S601), the modulation method used for modulating the transmission target signal is subsequently determined. , It is determined whether or not the modulation method has information on the amplitude (S602). Then, the base station apparatus 101 determines the boost amount and the number of repeated transmissions when the transmission target signal is modulated by a modulation method having no information in amplitude (NO in S602) (S603). For example, as described above, the base station apparatus 101 determines the boost amount based on the total amount of electric power available for signal transmission and the electric power used for signal transmission in LTE, and obtains a predetermined radio quality. The boost amount and the number of repeated transmissions are determined so as to compress the number of repeated transmissions within the range to be satisfied. Then, the base station apparatus 101 increases the transmission power of the data signal by the boost amount determined in S603, and repeatedly transmits the signal as many times as the number of repeated transmissions determined in S603 (S604). The process of S603 can be executed for each subframe based on the amount of resources actually used in LTE and the like. That is, the processes of S603 and S604 may be repeatedly executed during the repeated transmission of one data signal. Further, the boost amount determined in S603 is not applied to signals used for measurement, cell search, and channel estimation, such as reference signals. As a result, the terminal device 102 can perform appropriate measurement, cell search, and channel estimation. However, since the channel estimate is obtained based on the unboosted amplitude, the phase can be a correct estimate when considering the data signal with boosted transmission power as a reference, but the amplitude estimate (attenuation by channel). Can be said to be incorrect. However, since the processing of S602 boosts the transmission power of the data signal modulated by the modulation method having no information on the amplitude, a correct demodulation result can be obtained even if the attenuation value by the channel is not appropriate. It becomes possible.

On the other hand, in the base station apparatus 101, when the conditions for executing the boost of the transmission signal and the determination of the number of repeated transmissions are not satisfied (NO in S601), the modulation method used to modulate the transmission target signal has an amplitude. In the case of the modulation method having the information in (S602, YES), the signal is transmitted by using the predetermined power determined prior to the communication and the predetermined number of repeated transmissions (S604).

As described above, by boosting the transmission power of at least a part of the transmission signals, the base station apparatus 101 has a high probability that at least a predetermined sufficient radio quality can be satisfied in the downlink direction. .. Further, when the number of repeated transmissions can be reduced by boosting the transmission power, the reduced radio resources can be allocated for the repeated transmission of the uplink, and as a result, the uplink direction However, there is a high probability that a predetermined sufficient radio quality can be satisfied. At this time, by not performing power boosting for a predetermined signal such as a reference signal, it is possible to suppress the influence on the radio quality measurement, channel estimation, and cell search in the terminal device 102. In addition, the power boost is performed only when the data signal modulation method does not have information on the amplitude, and the power boost is not performed when the method having information on the amplitude is used. The device 102 can be allowed to accurately demodulate the signal.

As described above, according to the method described in the present embodiment, an unnecessarily large number of repeated transmissions is not set, so that waste of wireless resources can be prevented.

Claims (14)

The base station device in a wireless communication system capable of executing communication with a predetermined radio quality by repeatedly transmitting signals between the base station device and the terminal device.
A communication means that wirelessly communicates with the terminal device,
A control means for controlling the communication means and
Have,
The control means
The transmission power of the signal transmitted to the terminal device and the repetition of the signal transmitted to the terminal device are repeated based on at least whether or not the signal transmitted to the terminal device is modulated by a predetermined modulation method having no information on the amplitude. Determine the number of transmissions and
Using the determined transmission power and the number of repeated transmissions, the communication means is controlled so as to transmit a signal to the terminal device.
A base station device characterized by that. The control means
The transmission power of the signal modulated by the predetermined modulation method is determined as a power higher than the predetermined power determined between the base station device and the terminal device prior to the communication.
The transmission power of a signal that is not modulated by the predetermined modulation method is determined as the same power as the predetermined power.
The base station apparatus according to claim 1. The control means determines the number of times of repeated transmissions capable of obtaining the predetermined radio quality of the signal transmitted to the terminal device based on the transmission power.
The base station apparatus according to claim 1 or 2. The control means is based on the total amount of power that the base station device can use to transmit a signal and the power that the base station device is expected to use in another system different from the wireless communication system. The transmission power of a signal modulated by the predetermined modulation method is determined.
The base station apparatus according to any one of claims 1 to 3, wherein the base station apparatus is characterized by the above. The control means determines the transmit power of a signal modulated by the predetermined modulation scheme based on the power difference between the total amount of power and the power expected to be used in the other system.
The base station apparatus according to claim 4. The control means is used for each subframe.
Based on the amount of resources that the base station equipment allocates to the other system, identify the power that will be used in that other system.
The transmission power of the signal modulated by the predetermined modulation method is determined based on the total amount of the power and the specified power.
The base station apparatus according to claim 4. The control means identifies the power expected to be used in the other system based on statistics about the amount of resources used in the other system.
The base station apparatus according to any one of claims 4 to 6, characterized in that. The control means includes the amount of data to be transmitted in the other system, the type of data to be transmitted in the other system, and the data scheduled to be generated in the other system. Identify the amount of power that is expected to be used in the other system, based on at least one of
The base station apparatus according to any one of claims 4 to 6, characterized in that. The control means determines the number of repetitions based on a statistical value of power that can be used as the transmission power of a signal modulated by the predetermined modulation method.
The base station apparatus according to any one of claims 4 to 8. The control means is based on whether or not the signal transmitted to the terminal device is modulated by the predetermined modulation method when the value relating to the amount of radio resources used in the wireless communication system exceeds a predetermined value. Determines the transmission power and the number of repeated transmissions.
The base station apparatus according to any one of claims 1 to 9. The control means is based on whether or not the signal transmitted to the terminal device is modulated by the predetermined modulation method when the number of devices communicating with the base station device in the wireless communication system exceeds a predetermined number. The transmission power and the number of repeated transmissions are determined.
The base station apparatus according to any one of claims 1 to 10. The control means transmits to the terminal device when the terminal device cannot satisfy the predetermined radio quality even by uplink or downlink communication using a predetermined number of repeated transmissions. The transmission power and the number of repeated transmissions are determined based on whether or not the signal to be modulated is modulated by the predetermined modulation method.
The base station apparatus according to any one of claims 1 to 11. A method for controlling a base station device in a wireless communication system capable of executing communication with a predetermined radio quality by repeatedly transmitting a signal between the base station device and the terminal device.
The base station device has a communication means for wirelessly communicating with the terminal device.
The control method is
The control means transmits the transmission power of the signal transmitted to the terminal device and the transmission to the terminal device based on at least whether or not the signal transmitted to the terminal device is modulated by a predetermined modulation method having no information on the amplitude. The process of determining the number of times the signal to be repeatedly transmitted
A step in which the control means controls the communication means so as to transmit a signal to the terminal device using the determined transmission power and the number of repeated transmissions.
A control method characterized by including. To a computer provided in the base station device in a wireless communication system capable of executing communication with a predetermined radio quality by repeatedly transmitting a signal between the base station device and the terminal device.
The transmission power of the signal transmitted to the terminal device and the repetition of the signal transmitted to the terminal device are repeated based on at least whether or not the signal transmitted to the terminal device is modulated by a predetermined modulation method having no information on the amplitude. Let me decide the number of transmissions,
The communication means included in the base station device is controlled so as to transmit a signal to the terminal device using the determined transmission power and the number of repeated transmissions.
Program for.

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