JP2013048324A - Radio communication device and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology by which a communication partner device can appropriately receive a signal from a radio communication device.SOLUTION: A transmission power determination part 33 determines transmission power of a first system communication part 51 according to a MCS in the first system communication part 51 reported from a first system base station. A transmission power related value acquisition part 34 acquires a transmission power related value relating to the transmission power of the first system communication part 51 reported to the first system base station. A transmission power reduction determination part 35 determines whether or not the transmission power of the first system communication part 51 is necessary to be reduced. An offset addition part 36 adds an offset value to the transmission power related value, when it is determined that the transmission power of the first system communication part 51 is necessary to be reduced. The first system base station determines the MCS in the first system communication part 51 on the basis of the transmission power related value reported from the first system communication part 51, and reports the MCS to a plural system terminal 2.

Description

  The present invention relates to wireless communication technology.

  Conventionally, various techniques relating to wireless communication have been proposed. For example, Patent Literature 1 discloses a wireless communication apparatus that can communicate using a plurality of wireless communication methods.

JP 2008-136118 A

  When the wireless communication device transmits a signal to the communication partner device, it is desired that the communication partner device appropriately receives the signal.

  Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide a technique that allows a communication partner apparatus to appropriately receive a signal from a wireless communication apparatus.

  In order to solve the above problems, a wireless communication device according to the present invention is notified from the communication partner device among a communication unit that performs wireless communication with the communication partner device, and a modulation scheme and a coding rate in the communication unit. A transmission power determination unit that determines transmission power of the communication unit according to at least one, and an acquisition unit that acquires a transmission power related value related to the transmission power of the communication unit, which is notified from the communication unit to the communication counterpart device; A determination unit that determines whether or not the transmission power of the communication unit needs to be reduced, and an offset with respect to the transmission power related value when the determination unit determines that the transmission power of the communication unit needs to be reduced And an offset addition unit for adding values.

  In one aspect of the wireless communication apparatus according to the present invention, a second communication unit that communicates using a wireless communication method different from the communication unit is further provided, and the determination unit includes the communication unit and the second communication. When the communication unit simultaneously communicates and the intensity of interference that the transmission signal of the communication unit gives to the reception signal of the second communication unit exceeds an allowable value, it is determined that the transmission power of the communication unit needs to be reduced .

  In one aspect of the wireless communication apparatus according to the present invention, a second communication unit that communicates using a wireless communication method different from the communication unit is further provided, and the determination unit includes the communication unit and the second communication. When the units communicate simultaneously, if the transmission power of the entire wireless communication device exceeds an allowable value, it is determined that the transmission power of the communication unit needs to be reduced.

  In one aspect of the wireless communication apparatus according to the present invention, the offset adding unit does not add the offset value to the transmission power related value when the communication unit and the second communication unit do not communicate simultaneously. .

  Further, in one aspect of the wireless communication device according to the present invention, a battery for generating a power source of the wireless communication device is further provided, and the determination unit is configured to output the communication unit when an output voltage of the battery becomes smaller than a threshold value. It is determined that it is necessary to reduce the transmission power.

  Further, in one aspect of the wireless communication device according to the present invention, a second communication unit that communicates using a wireless communication method different from the communication unit, and a battery that generates a power source of the wireless communication device are further provided, The determination unit determines that the transmission power of the communication unit needs to be reduced when the output voltage of the battery becomes smaller than a threshold value.

  Moreover, the wireless communication device according to the present invention corresponds to at least one notified from the communication partner device among a communication unit that performs wireless communication with the communication partner device, and a modulation scheme and a coding rate in the communication unit. A transmission power determination unit that determines transmission power of the communication unit, an acquisition unit that acquires a transmission power related value related to the transmission power of the communication unit, which is notified from the communication unit to the communication counterpart device, and A determination unit that determines whether or not transmission power has decreased unintentionally, and if the determination unit determines that the transmission power of the communication unit has decreased unintentionally, an offset value is added to the transmission power related value And an offset adding unit.

  Further, in one aspect of the wireless communication device according to the present invention, a battery for generating a power source of the wireless communication device is further provided, and the determination unit is configured to output the communication unit when an output voltage of the battery becomes smaller than a threshold value. It is determined that the transmission power has decreased unintentionally.

  Further, in one aspect of the wireless communication apparatus according to the present invention, the offset adding unit transmits the transmission when the output voltage of the battery becomes equal to or greater than a second threshold value equal to or greater than the threshold value. The offset value is not added to the power related value.

  Further, in one aspect of the wireless communication apparatus according to the present invention, the transmission power related value indicates transmission power of the communication unit when the communication unit transmits the transmission power related value, and the offset value is positive. Value.

  Further, in one aspect of the wireless communication apparatus according to the present invention, the transmission power related value indicates a margin of transmission power in the communication unit when the communication unit transmits the transmission power related value, and the offset The value is a negative value.

  In one aspect of the wireless communication apparatus according to the present invention, the transmission power related value indicates a maximum transmission power of the communication unit, and the offset value is a negative value.

  The wireless communication system according to the present invention includes a first wireless communication device and a second wireless communication device that performs wireless communication with the first wireless communication device, and the first wireless communication device includes the second wireless communication device. Transmission power of the first communication unit according to at least one notified from the second wireless communication device among the first communication unit that performs wireless communication with the device and the modulation scheme and the coding rate in the first communication unit A transmission power determination unit for determining transmission power, an acquisition unit for acquiring a transmission power related value related to transmission power of the first communication unit, which is notified from the first communication unit to the second wireless communication device, and the first communication A determination unit that determines whether or not the transmission power of the unit needs to be reduced, and an offset value relative to the transmission power related value when the determination unit determines that the transmission power of the first communication unit needs to be reduced Offset adder for adding And the second wireless communication device includes: a second communication unit that performs wireless communication with the first wireless communication device; and the transmission power related value received by the second communication unit. A determination unit that determines at least one of a modulation scheme and a coding rate in the communication unit, and the second communication unit is determined by the determination unit based on the transmission power related value. The first wireless communication apparatus is notified of at least one of the modulation method and the coding rate.

  The wireless communication system according to the present invention includes a first wireless communication device and a second wireless communication device that performs wireless communication with the first wireless communication device, and the first wireless communication device includes the second wireless communication device. Transmission power of the first communication unit according to at least one notified from the second wireless communication device among the first communication unit that performs wireless communication with the device and the modulation scheme and the coding rate in the first communication unit A transmission power determination unit that determines a transmission power related value related to transmission power of the first communication unit, which is notified from the first communication unit to the second wireless communication device; A determination unit that determines whether or not the transmission power has decreased unintentionally, and when the determination unit determines that the transmission power of the first communication unit has decreased unintentionally, an offset value relative to the transmission power related value. Offset adder for adding And the second wireless communication device includes: a second communication unit that performs wireless communication with the first wireless communication device; and the transmission power related value received by the second communication unit. A determination unit that determines at least one of a modulation scheme and a coding rate in the communication unit, and the second communication unit is determined by the determination unit based on the transmission power related value. The first wireless communication apparatus is notified of at least one of the modulation method and the coding rate.

  According to the present invention, even if the transmission power of the wireless communication apparatus is reduced, the communication partner apparatus can appropriately receive a signal from the wireless communication apparatus.

It is a figure which shows the structure of a radio | wireless communications system. It is a figure which shows the structure of a 1st system base station and a 2nd system base station. It is a figure which shows the detailed structure of a 1st system base station. It is a figure which shows an example of a MCS-reception power table. It is a figure which shows the structure of a multi-method terminal. It is a flowchart which shows operation | movement of a multi-type terminal. It is a flowchart which shows operation | movement of a multi-type terminal.

  FIG. 1 is a diagram showing a configuration of a wireless communication system 100 according to the present embodiment. In radio communication system 100 according to the present embodiment, a plurality of radio communication schemes, for example, two radio communication schemes are used. In the wireless communication system 100, for example, WiMAX (Worldwide Interoperability for Microwave Access) and W-CDMA (Wideband Code Division Multiple Access) are used. Instead of a combination of WiMAX and W-CDMA, a combination of LTE (Long Term Evolution) and W-CDMA, a combination of WiMAX and WiFi (Wireless Fidelity), or the like may be used. W-CDMA is also referred to as “UTRA (UMTS Terrestrial Radio Access) -FDD (Frequency Division Duplex)”. In WiMAX and LTE, an OFDM (Orthogonal Frequency Division Multiplexing) signal in which a plurality of subcarriers are superimposed is used for communication between a base station and a communication terminal.

  As shown in FIG. 1, a wireless communication system 100 includes a plurality of first mode base stations 1a (only one first mode base station 1a is shown in FIG. 1) that communicate using WiMAX, and W-CDMA. And a plurality of second-system base stations 1b (only one second-system base station 1b is shown in FIG. 1). The wireless communication system 100 is also provided with a plurality of communication terminals 2 (only one communication terminal 2 is shown in FIG. 1) capable of communicating using both WiMAX and W-CDMA. The communication terminal 2 can communicate with each of the first system base station 1a and the second system base station 1b. Hereinafter, this communication terminal 2 is referred to as a “multiple mode terminal 2”.

  Although not shown, the wireless communication system 100 is also provided with a communication terminal that communicates using only WiMAX and a communication terminal that communicates using only W-CDMA. A communication terminal that communicates using a single wireless communication method, such as a communication terminal that communicates using only WiMAX, is referred to as a “single method terminal”.

<Base station configuration>
The schematic configurations of the first mode base station 1a and the second mode base station 1b are the same. As shown in FIG. 2, each of the first mode base station 1a and the second mode base station 1b includes a radio communication unit 10 that performs radio communication using an antenna 10a, and a control unit 11 that controls the radio communication unit 10. And.

  The wireless communication unit 10 performs amplification processing, down-conversion, A / D conversion processing, and the like on the reception signal received by the antenna 10a, and generates and outputs a baseband reception signal. The radio communication unit 10 performs D / A conversion processing, up-conversion, amplification processing, and the like on the baseband transmission signal generated by the control unit 11 to generate a transmission signal in the carrier band. Then, the wireless communication unit 10 wirelessly transmits the generated transmission signal of the carrier band from the antenna 10a.

  The control unit 11 includes a CPU, a DSP, a memory, and the like. Various functions in the control unit 11 are realized by the CPU and the DSP executing programs in the memory. The control unit 11 performs demodulation processing, decoding processing, and the like on the reception signal output from the wireless communication unit 10 to reproduce and acquire control data and user data included in the reception signal. In addition, the control unit 11 generates a transmission signal, performs encoding processing, modulation processing, and the like on the transmission signal to generate a baseband transmission signal. Then, the control unit 11 inputs the generated baseband transmission signal to the wireless communication unit 10.

  In this Embodiment, since the operation | movement of the 1st system base station 1a which communicates using WiMAX is characteristic, the structure of the 1st system base station 1a is demonstrated in detail below. FIG. 3 is a diagram showing a detailed configuration of the first system base station 1a.

  As shown in FIG. 3, the CPU 11 and the DSP execute the program in the memory in the control unit 11 of the first mode base station 1a, so that the transmission / reception processing unit 110, the radio resource allocation unit 111, and the MCS determination unit 112 are performed. In addition, functional blocks such as the storage unit 113 are formed.

  The transmission / reception processing unit 110 performs demodulation processing, decoding processing, and the like on the reception signal output from the wireless communication unit 10 from the communication terminal, and reproduces control data and user data included in the reception signal. Get. The transmission / reception processing unit 110 generates a transmission signal to be transmitted to the communication terminal, performs modulation processing on the transmission signal, and generates a baseband transmission signal. Then, the transmission / reception processing unit 110 inputs the generated baseband transmission signal to the wireless communication unit 10. As a result, the first mode base station 1a is changed to a multiple mode terminal 2 capable of communicating using both WiMAX and W-CDMA, or a single communication terminal capable of communicating using only WiMAX. On the other hand, a transmission signal is wirelessly transmitted.

  The radio resource allocation unit 111 allocates downlink radio resources used by the radio communication unit 10 in downlink communication with the communication terminal to the communication terminal with which the radio communication unit 10 communicates. Specifically, the radio resource allocation unit 111 allocates a use frequency band and a use time zone that the radio communication unit 10 uses for downlink communication with the communication terminal to the communication terminal with which the radio communication unit 10 communicates. The radio resource allocation unit 111 allocates an uplink radio resource used by the radio communication unit 10 in uplink communication with the communication terminal to the communication terminal with which the radio communication unit 10 communicates. Specifically, the radio resource allocation unit 111 allocates a use frequency band and a use time zone that the radio communication unit 10 uses for uplink communication with the communication terminal to a communication terminal with which the radio communication unit 10 communicates. Hereinafter, the use frequency band that the wireless communication unit 10 uses for uplink communication with the communication terminal may be referred to as “uplink use frequency band”.

  The transmission / reception processing unit 110 generates a transmission signal to be transmitted to the communication terminal based on the downlink radio resource allocated to the communication terminal by the radio resource allocation unit 111, and the transmission signal at a timing based on the downlink radio resource. Is input to the wireless communication unit 10. Thereby, the transmission signal which should be transmitted to a communication terminal is transmitted from the radio | wireless communication part 10 using the downlink radio | wireless resource allocated to the said communication terminal.

  Also, the transmission / reception processing unit 110 generates and outputs a transmission signal including a downlink radio resource allocated to the communication terminal by the radio resource allocation unit 111 and a notification signal for notifying the communication terminal of the uplink radio resource. Thereby, the communication terminal can know the radio resources used in downlink communication and uplink communication with the first system base station 1a. Therefore, the communication terminal can appropriately receive the signal addressed to the own device from the first scheme base station 1a, and can also transmit the signal using the uplink radio resource allocated to the own device in the first scheme base station 1a. Can be sent.

  The MCS determination unit 112 determines an MCS (Modulation and Coding Scheme) used for transmission by the first scheme base station 1a. MCS indicates a combination of a modulation scheme such as QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and the coding rate of an error correction code. Based on the MCS determined by the MCS determination unit 112, the transmission / reception processing unit 110 performs encoding processing and modulation processing on the transmission signal.

  Further, the MCS determination unit 112 determines the MCS used for transmission by the communication terminal with which the first scheme base station 1a communicates. When the transmission / reception processing unit 110 determines the MCS to be used by the communication terminal to be communicated, the transmission / reception processing unit 110 generates a transmission signal including a notification signal for notifying the communication terminal 2 of the MCS and transmits the transmission signal to the wireless communication unit 10. input. Thereby, the MCS determined by the MCS determination unit 112 is notified to the communication terminal. When the MCS determining unit 112 determines the MCS to be used by the multi-method terminal 2 for transmission of the signal to the first-method base station 1a, the MCS determining unit 112 transmits a transmission power-related value described later notified from the multi-method terminal 2; The MCS-reception power table 113a stored in the storage unit 113 is used.

  FIG. 4 is a diagram illustrating an example of the MCS-reception power table 113a. In the column “MCS” in FIG. 4, the modulation scheme and coding rate are shown on the left and right sides of the hyphen, respectively. For example, in the MCS indicated by “QPSK-1 / 2”, the modulation scheme is QPSK and the coding rate is ½.

  The MCS-reception power table 113a describes a plurality of MCSs that can be used in WiMAX and have different combinations of modulation schemes and coding rates. Here, each of a plurality of MCSs usable in WiMAX is given a rank (rank) for instantaneous transmission throughput determined by a combination of a modulation scheme and a coding rate in the MCS. As the MCS rank increases, the instantaneous transmission throughput determined by the combination of the modulation scheme and coding rate in the MCS increases. In the MCS-reception power table 113a, a plurality of MCSs usable in WiMAX are described in rank order.

  In addition, in the MCS-reception power table 113a, when the communication terminal transmits a transmission signal having a certain frequency bandwidth generated based on the MCS to each of the plurality of MCSs described in the rank order, the first is performed. Desired received power for the system base station 1a to appropriately receive the transmission signal is associated. Hereinafter, the certain frequency bandwidth is referred to as “unit bandwidth”. The desired received power described in the MCS-received power table 113a is the desired received power per unit bandwidth. In WiMAX, for example, the frequency bandwidth of one subcarrier is adopted as the unit bandwidth. In WiMAX, as the desired received power, the received power relative to the noise power relative to the carrier, that is, C / N (Carrier to Noise ratio) is adopted. Hereinafter, the desired received power per unit bandwidth described in the MCS-received power table 113a is referred to as “normalized desired received power NRP”.

  In the MCS-received power table 113a, the normalized desired received power NRP associated with the MCS increases as the rank of the MCS increases. That is, P1 to P4 shown in FIG. 4 increase in this order. As the rank of the MCS used for transmission by the communication terminal increases, the base station becomes difficult to reproduce data included in the signal from the communication terminal. Therefore, in the MCS-reception power table 113a, the rank of the MCS increases. The normalized desired received power NRP associated therewith is increased.

  The method for determining the MCS used by the multi-mode terminal 2 for transmission to the first mode base station 1a will be described in detail later.

<Configuration of multiple terminals>
FIG. 5 is a diagram showing the configuration of the multi-method terminal 2. As shown in FIG. 5, the multi-method terminal 2 includes a radio communication unit 20 that performs radio communication with the first method base station 1a and the second method base station 1b, and a control unit 30 that controls the radio communication unit 20; The battery 40 is provided.

  The wireless communication unit 20 includes a first method wireless unit 21 that performs wireless communication with the first method base station 1a, and a second method wireless unit 22 that performs wireless communication with the second method base station 1b. The 1st system radio | wireless part 21 receives the transmission signal transmitted from the 1st system base station 1a with the antenna 21a. The first-system radio unit 21 performs amplification processing, down-conversion, A / D conversion processing, and the like on the reception signal received by the antenna 21a, and generates and outputs a baseband reception signal.

  The 2nd system radio | wireless part 22 receives the transmission signal which the 2nd system base station 1b transmits with the antenna 22a. The second-system radio unit 22 performs amplification processing, down-conversion, A / D conversion processing, and the like on the reception signal received by the antenna 22a, and generates and outputs a baseband reception signal.

  Further, the first scheme radio unit 21 performs D / A conversion processing, up-conversion, amplification processing, and the like on the baseband transmission signal generated by the control unit 30 according to WiMAX, so that the carrier band A transmission signal is generated. And the 1st system radio | wireless part 21 carries out radio transmission of the produced | generated transmission signal of the carrier band from the antenna 21a.

  The second-system radio unit 22 performs D / A conversion processing, up-conversion, amplification processing, and the like on the baseband transmission signal corresponding to W-CDMA, which is generated by the control unit 30, so that the carrier band is A transmission signal is generated. And the 2nd system radio | wireless part 22 radio-transmits the transmission signal of the produced | generated carrier band from the antenna 22a.

  The control unit 30 includes a CPU, a DSP, a memory, and the like. The control unit 30 includes a first method signal processing unit 31, a second method signal processing unit 32, a transmission power determination unit 33, a transmission power related value acquisition unit 34, as the CPU and the DSP execute the program in the memory. Functional blocks such as a transmission power reduction determination unit 35, an offset addition unit 36, and a storage unit 37 are formed.

  The first method signal processing unit 31 performs demodulation processing, decoding processing, and the like on the reception signal output from the first method wireless unit 21, and reproduces control data, user data, and the like included in the reception signal. Get. The first scheme signal processing unit 31 generates a transmission signal to be transmitted to the first scheme base station 1a, performs encoding processing, modulation processing, and the like on the transmission signal, and transmits baseband according to WiMAX. Generate a signal. The first scheme signal processing unit 31 performs encoding processing and modulation processing on the transmission signal based on the MCS notified from the first scheme base station 1a. Then, the first method signal processing unit 31 inputs the generated baseband transmission signal to the first method radio unit 21. Thereby, the transmission signal according to WiMAX is wirelessly transmitted from the first method wireless unit 21 to the first method base station 1a.

  The second system signal processing unit 32 performs demodulation processing, decoding processing, and the like on the reception signal output from the second system radio unit 22 to reproduce control data and user data included in the reception signal. Get. Further, the second system signal processing unit 32 generates a transmission signal to be transmitted to the second system base station 1b, performs encoding processing, modulation processing, and the like on the transmission signal, and performs baseband according to W-CDMA. The transmission signal is generated. Then, the second system signal processing unit 32 inputs the generated baseband transmission signal to the second system radio unit 22. Thereby, the transmission signal according to W-CDMA is wirelessly transmitted from the second method wireless unit 22 to the second method base station 1b.

  In the present embodiment, the first method wireless unit 21 and the first method signal processing unit 31 constitute a first method communication unit 51 that performs wireless communication with the first method base station 1a using WiMAX. The MCS used for transmission by the first scheme communication unit 51 is notified from the first scheme base station 1a. Further, in the present embodiment, the second method wireless unit 22 and the second method signal processing unit 32 constitute a second method communication unit 52 that communicates with the second method base station 1b using W-CDMA. Yes.

  The transmission power determination unit 33 determines the transmission power of each of the first method communication unit 51 and the second method communication unit 52. The transmission power determination unit 33 uses the MCS-reception power table 37 a stored in the storage unit 37 when determining the transmission power of the first scheme communication unit 51. The MCS-reception power table 37a is the same as the MCS-reception power table 113a stored in the storage unit 113 of the first scheme base station 1a.

  The transmission power related value acquisition unit 34 acquires a transmission power related value related to the transmission power of the first scheme communication unit 51. The transmission power reduction determination unit 35 determines whether or not the transmission power of the first scheme communication unit 51 needs to be reduced. When the transmission power reduction determination unit 35 determines that the transmission power of the first scheme communication unit 51 needs to be reduced, the offset addition unit 36 offsets the transmission power related value acquired by the transmission power related value acquisition unit 34. Add the values.

  The operations of the transmission power determination unit 33, the transmission power related value acquisition unit 34, the transmission power reduction determination unit 35, and the offset addition unit 36 will be described later in detail.

  The battery 40 generates a power source for the multi-method terminal 2. The output voltage (power supply voltage) of the battery 40 is supplied to each electronic component included in the wireless communication unit 20 and the control unit 30.

<Operation of transmission power determination unit of multi-method terminal>
Next, the operation in which the transmission power determination unit 33 of the multi-system terminal 2 determines the transmission power of the first system communication unit 51 will be described. The transmission power determination unit 33 according to the present embodiment determines the transmission power of the first method communication unit 51 according to the MCS in the first method communication unit 51.

  In radio communication system 100 according to the present embodiment, first scheme base station 1a periodically transmits a system information notification signal for notifying system information. At that time, the first system base station 1a includes its own transmission power (hereinafter referred to as “base station transmission power X”) when transmitting the system information notification signal in the system information. When the first system communication unit 51 receives the system information notification signal, the transmission power determination unit 33 calculates the reception power Y of the system information notification signal. Next, the transmission power determination unit 33 obtains the propagation loss L from the base station transmission power X included in the system information notified by the system information notification signal and the reception power Y of the system information notification signal. The propagation loss L is L = X−Y. The propagation loss L thus determined is a propagation loss per frequency bandwidth of the system information notification signal. Then, the transmission power determination unit 33 converts the calculated propagation loss L into a propagation loss per unit bandwidth. Hereinafter, this propagation loss per unit bandwidth is referred to as “normalized propagation loss NL”.

  On the other hand, the transmission power determination unit 33 refers to the MCS-reception power table 37a stored in the storage unit 37, and acquires the normalized desired reception power NRP corresponding to the MCS notified from the first scheme base station 1a. . Then, the transmission power determining unit 33 sets a value obtained by adding the normalized propagation loss NL and the normalized desired received power NRP as the transmission power per unit bandwidth.

  In WiMAX, the transmission power per unit bandwidth is obtained not only by the normalized propagation loss NL and the normalized desired received power NRP, but also by the received interference power at the first mode base station 1a. In this embodiment, in order to simplify the explanation, it is assumed that the normalized propagation loss NL and the normalized desired received power NRP are added to obtain the transmission power per unit bandwidth. Hereinafter, the transmission power per unit bandwidth is referred to as “normalized transmission power NSP”.

  Next, the transmission power determination unit 33 converts the normalized transmission power NSP into transmission power per frequency bandwidth of the transmission signal transmitted from the antenna 21a by the first scheme communication unit 51. This transmission power is the transmission power of the transmission signal to which the MCS notified from the first method base station 1a is applied, which is transmitted from the antenna 21a of the first method communication unit 51.

  As described above, the transmission power determination unit 33 determines the transmission power of the first method communication unit 51 based on the normalized desired received power NRP corresponding to the MCS in the first method communication unit 51. On the other hand, the higher the MCS rank in the first scheme communication unit 51, the higher the normalized desired received power NRP corresponding to it. Therefore, the higher the MCS rank in the first method communication unit 51, the higher the transmission power of the first method communication unit 51.

<Operation of Transmission Power Related Value Acquisition Unit of Multi-Mode Terminal>
The transmission power related value acquisition unit 34 according to the present embodiment acquires the transmission power value of the first method communication unit 51 when the first method communication unit 51 transmits the transmission power related value as the transmission power related value. doing. In this Embodiment, the 1st system communication part 51 notifies the transmission power related value to the 1st system base station 1a using the transmission signal of a predetermined | prescribed frequency bandwidth. The transmission power of the transmission signal is determined by the transmission power determination unit 33, and the transmission power related value acquisition unit 34 sets the value of the transmission power as the transmission power related value. Thereafter, the transmission signal used when the transmission power related value is notified to the first scheme base station 1a, that is, the transmission signal transmitted from the antenna 21a for notifying the transmission power related value is referred to as “related value notification signal”. "

<Determining method of MCS used by multiple mode terminal for transmission to first mode base station>
Next, the operation of the MCS determination unit 112 when the MCS determination unit 112 of the first mode base station 1a determines the MCS to be used for transmission by the first mode communication unit 51 of the multiple mode terminal 2 will be described in detail. . In the present embodiment, the MCS determination unit 112 determines the MCS used by the first method communication unit 51 based on the transmission power margin of the first method communication unit 51 of the multi-method terminal 2. Hereinafter, the target multi-method terminal 2 will be referred to as “target multi-method terminal 2”.

  The MCS determination unit 112 uses the uplink radio resource allocated to the target multiple mode terminal 2 by the radio resource allocation unit 111 and the first mode communication unit 51 of the target multiple mode terminal 2 transmits the transmission signal. The margin of the transmission power of the 1-system communication unit 51 is obtained. Hereinafter, this margin is referred to as “transmission power margin HR”. Generally, the margin of transmission power of a wireless communication device is called “headroom”. The transmission power margin HR is expressed by the following equation (1).

HR = SPmax-SP (1)
SPmax in the equation (1) indicates the maximum transmission power in the first method communication unit 51 of the target multi-method terminal 2. When each multi-method terminal 2 is connected to the network via the first-method base station 1a, each of the first-method base stations 1a and Notify the maximum transmission power in each.

  In addition, the SP of Expression (1) is a transmission signal transmitted by the first method communication unit 51 of the target multi-method terminal 2 using the uplink radio resource assigned to the target multi-method terminal 2 by the first method base station 1a. The transmission power prediction value (hereinafter referred to as “transmission power prediction value”) is shown. The predicted transmission power value SP is obtained based on the transmission power related value notified from the target multi-method terminal 2. Specifically, the MCS determination unit 112 sets the transmission power related value indicated by the related value notification signal transmitted from the target multi-method terminal 2, that is, the transmission power per frequency bandwidth of the related value notification signal, to the first value. The system base station 1a converts the transmission power per bandwidth of the uplink use frequency band assigned to the target multi-system terminal 2 and uses the converted transmission power obtained thereby as the transmission power predicted value SP.

  When obtaining the transmission power margin HR, the MCS determination unit 112 uses the transmission power margin HR and the MCS-reception power table 113a stored in the storage unit 113 to perform the first scheme communication of the target multiple scheme terminal 2. The unit 51 determines the MCS to be used for uplink communication. Below, this operation | movement of the MCS determination part 112 is demonstrated in detail.

  When the transmission power margin HR is a positive value, the MCS determination unit 112 sets the MCS rank used by the first method communication unit 51 of the target multiple method terminal 2 in uplink communication to be one higher than the current rank. Determine if it can be lifted.

  Specifically, the MCS determination unit 112 first refers to the MCS-reception power table 113a, and uses the MCS currently used by the first method communication unit 51 of the target multi-method terminal 2 (hereinafter “used MCS”). Normalized desired received power NRP corresponding to “.

  Next, the MCS determination unit 112 refers to the MCS-reception power table 113a, and is associated with the MCS that is one rank higher than the MCS in use of the first method communication unit 51 of the target multi-method terminal 2. Normalized desired received power NRP is acquired.

  Next, the MCS determination unit 112 ranks the normalized desired received power NRP associated with the in-use MCS of the first mode communication unit 51 of the target multi-mode terminal 2 by one rank higher than the in-use MCS. A value obtained by subtracting from the normalized desired received power NRP associated with the MCS is obtained. Hereinafter, this value is referred to as “a positive normalized desired received power difference for one rank”. In the example of FIG. 4, assuming that the in-use MCS is “QPSK-3 / 4”, “P3−P2” is a positive normalized desired received power difference for one rank.

  Next, the MCS determination unit 112 determines the power per bandwidth of the uplink use frequency band that the first method base station 1a assigns the positive normalized desired received power difference for one rank to the target multiple method terminal 2. Convert to difference. For example, assuming that the unit bandwidth is 10 kHz and the bandwidth of the uplink use frequency band assigned to the target multiple-system terminal 2 by the first system base station 1a is 1 MHz, considering the true number expression, it is equivalent to one rank. The positive normalized desired received power difference is multiplied by 100. Thereafter, a value obtained by converting the positive normalized desired received power difference for one rank into the power difference per bandwidth of the uplink use frequency band allocated to the target multiple-system terminal 2 by the first-system base station 1a is “ This is referred to as “positive received power difference for one rank”.

  Next, the MCS determination unit 112 determines whether or not the transmission power margin HR is greater than or equal to the positive reception power difference for one rank. When the transmission power margin HR is smaller than the positive reception power difference for one rank, the MCS determination unit 112 assumes that there is no margin in the transmission power of the first scheme communication unit 51 of the target multi-method terminal 2 Then, it is determined that the rank of the MCS used by the first method communication unit 51 for uplink communication cannot be raised to the rank one higher than the current rank. Accordingly, in this case, the in-use MCS is maintained as the MCS used by the first method communication unit 51 of the target multiple method terminal 2 in the uplink communication.

  On the other hand, when the transmission power margin HR is equal to or greater than the positive reception power difference for one rank, the MCS determination unit 112 has a margin for the transmission power of the first method communication unit 51 of the target multi-method terminal 2. As a result, it is determined that the rank of the MCS that the first method communication unit 51 uses for uplink communication can be raised to one rank higher than the current rank.

  If the MCS determination unit 112 determines that the first method communication unit 51 of the target multi-method terminal 2 can raise the rank of the MCS used for uplink communication to a higher rank, the first MCS terminal 2 of the target multi-method terminal 2 The system communication unit 51 determines whether it is possible to raise the rank of the MCS used in uplink communication to the next higher rank. In this case, the MCS determination unit 112 first ranks the normalized desired received power NRP associated with the in-use MCS of the first method communication unit 51 of the target multi-method terminal 2 over the in-use MCS. Is a value obtained by subtracting from the normalized desired received power NRP associated with the MCS that is two higher than the MCS, as a positive normalized desired received power difference for two ranks.

  Next, the MCS determination unit 112 calculates the power per bandwidth of the uplink use frequency band that the first method base station 1a assigns the positive normalized desired received power difference for two ranks to the target multiple method terminal 2. It is converted into a difference (hereinafter referred to as “a positive received power difference for two ranks”).

  Next, the MCS determination unit 112 determines whether or not the transmission power margin HR is greater than or equal to the positive reception power difference for two ranks. When the transmission power margin HR is smaller than the positive reception power difference for two ranks, the MCS determination unit 112 determines the rank of the MCS that the first method communication unit 51 uses for uplink communication as the current rank. It is determined that it cannot be raised to the next higher rank. On the other hand, when the transmission power margin HR is greater than or equal to the positive reception power difference for two ranks, the MCS determination unit 112 determines the rank of the MCS that the first method communication unit 51 uses for uplink communication, It is determined that the current rank can be raised to the next higher rank.

  If the MCS determination unit 112 determines that the first method communication unit 51 of the target multi-method terminal 2 can raise the rank of the MCS used for uplink communication to the next higher rank, similarly, the target multi-method terminal The second first method communication unit 51 determines whether it is possible to raise the rank of MCS used in uplink communication to a rank three higher than the current rank.

  Thereafter, the MCS determination unit 112 operates in the same manner, and to what rank can the MCS rank used by the first mode communication unit 51 of the target multiple mode terminal 2 for uplink communication be raised from the current rank? Is identified. Then, the MCS determination unit 112 determines the highest rank MCS that can be raised as a new MCS that the first method communication unit 51 of the target multi-method terminal 2 uses for uplink communication.

  If the transmission power margin HR is zero, the MCS determination unit 112 determines that the rank of the in-use MCS of the first method communication unit 51 of the target multiple method terminal 2 is appropriate, and the first method communication The unit 51 determines not to change the rank of the MCS used for uplink communication.

  When the transmission power margin HR is a negative value, the MCS determination unit 112 reduces the rank of the MCS used by the first method communication unit 51 of the target multiple method terminal 2 by one in the uplink communication. It is determined whether the transmission power margin HR is zero or more.

  Specifically, the MCS determination unit 112 ranks the normalized desired received power NRP associated with the in-use MCS of the first method communication unit 51 of the target multi-method terminal 2 with a rank higher than that of the in-use MCS. A value subtracted from the normalized desired received power NRP associated with the next MCS is obtained as a negative normalized desired received power difference for one rank.

  Next, the MCS determination unit 112 determines the power per bandwidth of the uplink use frequency band that the first method base station 1a assigns the negative normalized desired received power difference for one rank to the target multiple method terminal 2. Convert to difference. Hereinafter, the power difference is referred to as “a negative received power difference for one rank”.

  Next, the MCS determination unit 112 adds the negative received power difference for one rank to the transmission power margin HR obtained using the equation (1), and obtains the value obtained thereby as the target. The transmission power margin HR when the rank of the MCS used by the first method communication unit 51 of the multi-method terminal 2 is lowered by one is used. Hereinafter, the transmission power margin HR when the rank of the MCS used by the first scheme communication unit 51 of the target multiple scheme terminal 2 is lowered by one is referred to as “transmission power margin HR one rank lower”.

  Next, the MCS determination unit 112 determines whether the transmission power margin HR below one rank has become zero or more. If the MCS determination unit 112 determines that the transmission power margin HR lower by one rank is zero or more, the MCS determination unit 112 uses one MCS rank used by the first method communication unit 51 of the target multi-method terminal 2 as compared with the current rank. It is decided to lower the MCS, and the MCS that is one rank lower than the MCS in use is set as a new MCS.

  On the other hand, when the transmission power margin HR below one rank is still a negative value, the MCS determination unit 112 sets two ranks of MCS used by the first method communication unit 51 of the target multi-method terminal 2. If it is lowered, it is determined whether the transmission power margin HR is zero or more.

  Specifically, the MCS determination unit 112 sets the normalized desired received power NRP associated with the in-use MCS of the first mode communication unit 51 of the target multiple mode terminal 2 to a rank that is higher than that of the in-use MCS. A value subtracted from the normalized desired received power NRP associated with the next MCS is obtained as a negative normalized desired received power difference for two ranks.

  Next, the MCS determination unit 112 determines the power per bandwidth of the uplink use frequency band that the first method base station 1a assigns the negative normalized desired received power difference for two ranks to the target multiple method terminal 2. Convert to difference. Hereinafter, the power difference is referred to as “negative received power difference for two ranks”.

  Next, the MCS determination unit 112 adds the negative reception power difference for two ranks to the transmission power margin HR obtained using the equation (1), and calculates the value obtained thereby. The transmission power margin HR (hereinafter referred to as “transmission power margin HR lower by two ranks”) when the rank of the MCS used by the first method communication unit 51 of the multi-method terminal 2 is lowered by two.

  Next, the MCS determination unit 112 determines whether the transmission power margin HR below two ranks is equal to or greater than zero. When the MCS determination unit 112 determines that the transmission power margin HR lower by two ranks is equal to or greater than zero, the MCS determination unit 112 uses two MCS ranks used by the first method communication unit 51 of the target multi-method terminal 2 as compared with the current rank. It is decided to lower it, and the MCS that is two ranks lower than the MCS in use is set as a new MCS.

  On the other hand, when the transmission power margin HR two ranks below is still a negative value, the MCS determination unit 112 similarly uses the MCS used by the first method communication unit 51 of the target multi-method terminal 2. When the rank is lowered by three, it is determined whether or not the transmission power margin HR is zero or more.

  Thereafter, the MCS determination unit 112 operates in the same manner, and if the rank of the MCS used by the first method communication unit 51 of the target multi-method terminal 2 for uplink communication is lowered from the current rank to which rank, the transmission power margin Specify whether the degree HR is greater than or equal to zero. Then, the MCS determination unit 112 determines an MCS having a rank with a transmission power margin HR of zero or more as a new MCS that the first method communication unit 51 of the target multiple method terminal 2 uses for uplink communication.

  Each time the MCS determination unit 112 assigns a new uplink radio resource to the target multi-method terminal 2 in the radio resource allocation unit 111, the MCS determination unit 112 generates a new one that the first method communication unit 51 of the target multi-method terminal 2 uses for uplink communication. The correct MCS is determined as described above. The new MCS determined by the MCS determination unit 112 is notified to the target multi-method terminal 2 through the wireless communication unit 10. In the target multiple mode terminal 2, when a new MCS is notified from the first mode base station 1a, the transmission power determination unit 33 determines the transmission power of the first mode communication unit 51 according to the new MCS.

  Note that, for example, if the distance between the target multi-method terminal 2 and the first method base station 1a becomes short, the propagation loss between them decreases, so the first method communication unit 51 of the target multi-method terminal 2 The transmission power of becomes smaller. Therefore, when the distance between the target multi-method terminal 2 and the first method base station 1a is reduced, the transmission power margin HR for the first method communication unit 51 of the target multi-method terminal 2 is increased. As a result, the rank of the MCS used by the first method communication unit 51 is increased.

  On the other hand, if the distance between the target multiple mode terminal 2 and the first mode base station 1a increases, the propagation loss between them increases, so that the first mode communication unit 51 of the target multiple mode terminal 2 Transmission power increases. Therefore, when the distance between the target multi-method terminal 2 and the first method base station 1a increases, the transmission power margin HR for the first method communication unit 51 of the target multi-method terminal 2 decreases. As a result, the rank of the MCS used by the first method communication unit 51 is lowered.

<Method for reducing transmission power of first communication unit of multi-terminal>
As described above, in the wireless communication system 100 according to the present embodiment, the first method base station 1a determines the transmission power related value related to the transmission power of the first method communication unit 51 notified from the multiple method terminal 2. Based on this, the MCS used by the first method communication unit 51 is determined, and the multi-method terminal 2 determines the transmission power of the first method communication unit 51 according to the MCS. Thereby, the first mode base station 1a appropriately receives the transmission signal generated based on the MCS determined by the first mode base station 1a and transmitted by the first mode communication unit 51 of the multi-mode terminal 2. Is possible.

  On the other hand, when the multi-method terminal 2 needs to reduce the transmission power of the first method communication unit 51 for some reason, if the transmission power of the first method communication unit 51 is arbitrarily reduced, The transmission power of the first method communication unit 51 does not become a value corresponding to the MCS used by the first method communication unit 51. Therefore, in the first scheme base station 1a, the reception power of the transmission signal from the first scheme communication unit 51 becomes a value smaller than the reception power necessary for properly receiving the transmission signal, and the transmission signal is There is a possibility that it cannot be received properly. As a result, in the first system base station 1a, there may be many data reception errors from the first system communication unit 51.

  Therefore, in the multi-method terminal 2 according to the present embodiment, when the transmission power reduction determination unit 35 determines that the transmission power of the first method communication unit 51 needs to be reduced, the offset addition unit 36 performs the first method base. The station 1a adds an offset value to the transmission power related value used when determining the MCS in the first scheme communication unit 51. When the offset value is added to the transmission power related value, the first method communication unit 51 notifies the first method base station 1a of the transmission power related value to which the offset value is added. Thereby, the transmission power of the 1st system communication part 51 can be made small, setting it as the value according to MCS in the said 1st system communication part 51 concerned. As a result, even if the transmission power of the first method communication unit 51 of the multi-method terminal 2 is reduced, the first method base station 1a can appropriately receive the transmission signal from the first method communication unit 51. .

  In the present embodiment, the transmission power reduction determination unit 35 determines that the transmission signal of the first method communication unit 51 is the second method communication unit when the first method communication unit 51 and the second method communication unit 52 communicate simultaneously. When the intensity of interference given to the received signal 52 exceeds the allowable value, it is determined that the transmission power of the first method communication unit 51 needs to be reduced.

  Furthermore, the transmission power reduction determination unit 35 transmits the transmission power of the entire multi-system terminal 2 (transmission power of the entire radio communication unit 20 when the first system communication unit 51 and the second system communication unit 52 communicate simultaneously. ) Exceeds the allowable value, it is determined that the transmission power of the first method communication unit 51 needs to be reduced. The allowable value of the transmission power in the entire multi-system terminal 2 is determined based on, for example, the allowable value of the specific absorption rate (SAR) for the multi-system terminal 2. That is, the allowable value of the transmission power in the entire multi-modal terminal 2 is set to a value such that the specific absorption rate for the multi-modal terminal 2 is less than or equal to the allowable value by making the transmission power equal to or lower than the allowable value. Is set.

  Hereinafter, the operation of the multi-modal terminal 2 when the multi-modal terminal 2 adds an offset value to the transmission power related value will be described in detail.

  FIG. 6 is a diagram illustrating an operation of the target multi-method terminal 2 when the target multi-method terminal 2 hands over from the second method base station 1b to the first method base station 1a. In the present embodiment, each multi-modal terminal 2 performs a Make-Before-Break type handover. Therefore, each multi-modal terminal 2 starts connection with the handover destination base station while communicating with the handover source base station.

  As shown in FIG. 6, when the second method communication unit 52 is communicating with the second method base station 1b in step s1, the target multi-method terminal 2 is the first method base station in step s2. When the control unit 30 determines that the condition for starting the handover to 1a is established, the target multi-method terminal 2 notifies the first-method base station 1a to that effect. When the first mode base station 1a permits the handover of the target multiple mode terminal 2 to the own device, the first mode base station 1a notifies the target multiple mode terminal 2 to that effect. Then, in step s3, the target multi-method terminal 2 starts a handover to the first method base station 1a. At this time, in the target multiple method terminal 2, the first method communication unit 51 starts connection to the first method base station 1a while the second method communication unit 52 communicates with the second method base station 1b. Thereby, the 1st system communication part 51 and the 2nd system communication part 52 come to communicate simultaneously. The determination as to whether or not the condition for starting the handover to the first mode base station 1a by the target multiple mode terminal 2 may be made in the first mode base station 1a.

  When the first method communication unit 51 and the second method communication unit 52 communicate simultaneously, the transmission power reduction determination unit 35 determines that the transmission signal of the first method communication unit 51 is the second method communication unit 52 in step s4. It is determined whether the intensity of interference given to the received signal exceeds an allowable value. Specifically, for example, the transmission power reduction determination unit 35 receives a signal received by the second method communication unit 52 before the first method communication unit 51 starts communication with the first method base station 1a that is the handover destination. The CIR (Carrier-to-Interference Ratio) and the CIR of the received signal at the second mode communication unit 52 after the first mode communication unit 51 starts communication with the first mode base station 1a as the handover destination Thus, a value obtained by subtracting the latter CIR from the former CIR is obtained. This difference value indicates the strength of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52. If the obtained difference value is larger than the threshold value, the transmission power reduction determination unit 35 determines that the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is an allowable value. It is determined that On the other hand, if the obtained difference value is equal to or less than the threshold value, the transmission power reduction determination unit 35 allows the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52. It is determined that the value is less than or equal to the value.

  If the transmission power reduction determination unit 35 determines in step s4 that the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 exceeds the allowable value, in step s8. It is determined that the transmission power of the first method communication unit 51 needs to be reduced.

  On the other hand, if the transmission power reduction determination unit 35 determines that the strength of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is equal to or less than the allowable value, in step s5, the target It is determined whether the transmission power of the entire multi-method terminal 2 exceeds the allowable value. If the transmission power reduction determination unit 35 determines that the transmission power of the target multi-method terminal 2 as a whole exceeds the allowable value, it is necessary to reduce the transmission power of the first method communication unit 51 in step s8. Is determined. On the other hand, when the transmission power reduction determination unit 35 determines that the transmission power of the entire target multi-method terminal 2 is equal to or less than the allowable value, step s6 is executed.

  If it is determined in step s8 that the transmission power of the first scheme communication unit 51 needs to be reduced, step s9 is executed. In step s9, the offset addition unit 36 adds an offset value to the transmission power related value acquired by the transmission power related value acquisition unit 34. This offset value is set so that the rank of the MCS currently used by the first method communication unit 51 is lowered. When step s9 is executed, step s4 is executed again, and thereafter the target multi-method terminal 2 operates in the same manner.

  In the present embodiment, the offset value is, for example, a positive fixed value. In this embodiment, since the transmission power related value indicates the transmission power of the first scheme communication unit 51, the first scheme is obtained by adding a positive offset value to the transmission power related value. The transmission power of the first method communication unit 51 of the target multi-method terminal 2 is notified to the base station 1a larger than the actual value. As a result, in the first mode base station 1a, the transmission power margin HR for the first mode communication unit 51 of the target multiple mode terminal 2 is reduced.

  Here, as can be understood from the above description, when the transmission power margin HR in the first method communication unit 51 of the target multi-method terminal 2 is large, the first method base station 1a When the rank of 51 MCS is increased, the transmission power margin HR decreases. Furthermore, when the transmission power margin HR is negative, the first system base station 1a attempts to lower the rank of the MCS so that the transmission power margin HR becomes positive. Thereby, when the rank of MCS in the first method communication unit 51 is appropriately set, the transmission power margin HR for the first method communication unit 51 becomes a small positive value. As for the offset value, the band of the uplink use frequency band assigned by the first mode base station 1a to the first mode communication unit 51 of the target multiple mode terminal 2 by adding the offset value to the transmission power related value. Regardless of the width, the transmission power margin HR for the first method communication unit 51 is set to a value that is surely smaller than zero. When the transmission power margin HR for the first method communication unit 51 of the target multi-method terminal 2 is smaller than zero, at least one of the MCS ranks in the first method communication unit 51 is lowered. By adding the offset value to the transmission power related value, the rank of the MCS in the first method communication unit 51 of the target multi-method terminal 2 can be lowered.

  As described above, when it is necessary to reduce the transmission power of the first method communication unit 51 of the target multi-method terminal 2, the offset value is added to the transmission power-related value to thereby determine the first power of the target multi-method terminal 2. When the rank of the MCS in the 1-system communication unit 51 decreases, the normalized desired received power NRP associated with the MCS decreases, and thus the normalized transmission power NSP of the 1-system communication section 51 decreases. Therefore, the transmission power of the first method communication unit 51 decreases. As a result, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is reduced, and the transmission power of the target multiple method terminal 2 as a whole is reduced.

  In step s6, the control unit 30 determines whether or not the handover of the target multiple mode terminal 2 to the first mode base station 1a has been completed. If it is determined in step s6 that the handover has ended, that is, if the first method communication unit 51 and the second method communication unit 52 stop communicating at the same time, in step s7, the offset addition unit 36 determines the transmission power related value. The offset value is not added to the transmission power related value acquired by the acquisition unit 34. On the other hand, if it is determined in step s6 that the handover has not been completed, step s4 described above is executed again. Thereafter, the target multi-method terminal 2 operates in the same manner.

  When step s9 is executed a plurality of times during execution of the handover, in each step s9 after the second time, an offset is again made relative to the transmission power related value to which the offset value is added in the previous step s9. The value is added. Therefore, each time step s9 is executed, the offset value is added to the transmission power value related value.

  FIG. 7 shows the operation of the target multi-method terminal 2 in the target multi-method terminal 2 when the first method communication unit 51 performs voice communication and the second method communication unit 52 performs data communication at the same time. FIG.

  As shown in FIG. 7, when the second method communication unit 52 is performing data communication with a web server or the like via the second method base station 1b in step s11, the first method communication unit 51 is in step s12. When voice communication is performed with a mobile phone or the like via the first system base station 1a, the above-described step s4 is executed.

  In step s13, when the first method communication unit 51 is performing voice communication with the mobile phone or the like via the first method base station 1a, the second method communication unit 52 is connected via the second method base station 1b. When data communication is performed with a web server or the like, the above-described step s4 is executed.

  If it is determined in step s4 that the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 exceeds the allowable value, step s8 is executed, and transmission power is transmitted. The reduction determination unit 35 determines that the transmission power of the first method communication unit 51 needs to be reduced. On the other hand, when it is determined in step s4 that the intensity of interference that the transmission signal of the first scheme communication unit 51 gives to the reception signal of the second scheme communication unit 52 is equal to or less than the allowable value, the above-described step s5 is executed. The

  If it is determined in step s5 that the transmission power of the entire target multi-method terminal 2 exceeds the allowable value, step s8 is executed, and the transmission power reduction determination unit 35 transmits the transmission of the first method communication unit 51. It is determined that the power needs to be reduced.

  If it is determined in step s8 that the transmission power of the first scheme communication unit 51 needs to be reduced, the above-described step s9 is executed, and the transmission power related value acquired by the transmission power related value acquisition unit 34 is set. In contrast, an offset value is added. When step s9 is executed, step s4 is executed again, and then the target multi-method terminal 2 operates in the same manner.

  If it is determined in step s5 that the transmission power of the entire target multi-method terminal 2 is equal to or less than the allowable value, in step s15, the control unit 30 performs voice communication and second method communication unit of the first method communication unit 51. It is determined whether at least one of the 52 data communications is completed.

  If it is determined in step s15 that at least one of the voice communication of the first method communication unit 51 and the data communication of the second method communication unit 52 has been completed, that is, the first method communication unit 51 and the second method communication unit 52. Are not communicated at the same time, in step s16, the offset adding unit 36 does not add the offset value to the transmission power related value acquired by the transmission power related value acquiring unit 34. On the other hand, when it is determined in step s15 that the voice communication of the first method communication unit 51 and the data communication of the second method communication unit 52 are still performed at the same time, step s4 is executed again. Thereafter, the target multi-method terminal 2 operates in the same manner.

  In addition, when step s9 is executed a plurality of times while the voice communication of the first method communication unit 51 and the data communication of the second method communication unit 52 are simultaneously performed, the second and subsequent times are performed as described above. In step s9, the offset value is added again to the transmission power related value to which the offset value was added in the previous step s9.

  As described above, when the first method communication unit 51 and the second method communication unit 52 communicate simultaneously, when the transmission power of the first method communication unit 51 needs to be reduced, By adding the offset value, the rank of the MCS in the first method communication unit 51 can be lowered, thereby reducing the transmission power of the first method communication unit 51. That is, the transmission power of the first method communication unit 51 can be reduced while maintaining a value corresponding to the MCS in the first method communication unit 51. As a result, even if the transmission power of the first method communication unit 51 is reduced for the purpose of suppressing the interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52, the first method communication unit 51 The system base station 1a can appropriately receive the transmission signal from the first system communication unit 51.

  Even when the multi-method terminal 2 has a dithering function and relays communication between a plurality of radio communication apparatuses having different radio communication schemes, the first scheme communication section 51 and the second scheme communication section 52 are used. Will communicate at the same time. For example, in the multi-mode terminal 2, the first mode communication unit 51 uses WiFi and the second mode communication unit 52 uses WiFi, and the multi-mode terminal 2 uses WiFi. And the wireless communication device using WiMAX, the first method communication unit 51 and the second method communication unit 52 of the multi-method terminal 2 communicate at the same time. Therefore, even in such a case, by executing the above steps s4, s5, s8, and s9, the transmission power of the first method communication unit 51 is a value corresponding to the MCS in the first method communication unit 51. And can be made smaller.

<Various modifications>
<First Modification>
In the above example, when the transmission power of the entire multi-system terminal 2 exceeds the allowable value, only the first system communication section 51 of the first system communication section 51 and the second system communication section 52 transmits. Although the power is reduced, similarly to the first method communication unit 51, the transmission power of the second method communication unit 52 is controlled to be a value corresponding to the MCS in the second method communication unit 52. Similarly, the offset value may be added to the transmission power related value for the second scheme communication unit 52 to reduce only the transmission power of the second scheme communication unit 52. Further, when the transmission power of the entire multi-system terminal 2 exceeds the allowable value, the transmission power of both the first system communication unit 51 and the second system communication unit 52 may be reduced.

  In addition, when the intensity of interference that the transmission signal of the second method communication unit 52 gives to the reception signal of the first method communication unit 51 exceeds the allowable value, the transmission power of the first method communication unit 51 is reduced. Similarly, the transmission power of the second system communication unit 52 may be reduced.

<Second Modification>
In the multi-method terminal 2, when the first method communication unit 51 is communicating with the first method base station 1a and the output voltage of the battery 40 decreases, the first method communication unit 51 and the first method base station 1a. In order to maintain the communication with the terminal as long as possible, it may be desired to reduce the transmission power of the first method communication unit 51 and the power consumption of the multi-method terminal 2.

  Therefore, the transmission power reduction determination unit 35 determines whether the output voltage of the battery 40 is smaller than the threshold value th1, and when the output voltage of the battery 40 is smaller than the threshold value th1, the first method communication unit 51. It may be determined that it is necessary to reduce the transmission power. Thus, when the output voltage of the battery 40 becomes smaller than the threshold value th1, an offset value is added to the transmission power related value. As a result, the transmission power of the first method communication unit 51 can be reduced while maintaining a value corresponding to the MCS in the first method communication unit 51. Therefore, when the output voltage of the battery 40 decreases, the power consumption of the multi-method terminal 2 can be reduced, and the first-method base station 1a appropriately receives the transmission signal from the first-method communication unit 51. can do.

  In this case, when the battery 40 is charged and the output voltage of the battery 40 becomes equal to or greater than the threshold value th2 that is equal to or greater than the threshold value th1, the offset relative to the transmission power related value is obtained. Do not add values.

  Further, in the multi-method terminal 2, when the output voltage of the battery 40 becomes smaller than the threshold value th1, the second method communication unit is performed in the same manner as when the transmission power of the first method communication unit 51 is reduced. The transmission power of 52 may be reduced while setting the value according to the MCS in the second system communication unit 52. In this case, the transmission power of the second method communication unit 52 may be reduced while reducing the transmission power of the first method communication unit 51, or the transmission power of the first method communication unit 51 may be reduced. Instead, it may be made smaller.

  Moreover, when the 1st system communication part 51 and the 2nd system communication part 52 are communicating simultaneously, since the output voltage of the battery 40 tends to fall, in this case, the output voltage of the battery 40 is a threshold value. The possibility of becoming smaller than the value th1 increases. Therefore, in the case where only one of the first method communication unit 51 and the second method communication unit 52 is communicating, without determining whether the output voltage of the battery 40 has become smaller than the threshold th1, When the first method communication unit 51 and the second method communication unit 52 communicate at the same time, it may be determined whether the output voltage of the battery 40 has become smaller than the threshold value th1.

  Further, not only a multi-method terminal 2 capable of communicating using a plurality of wireless communication schemes, but also a single communication terminal such as a communication terminal communicating using only WiMAX or a communication terminal communicating using only W-CDMA. Also in the system terminal, when the output voltage of the battery becomes smaller than the threshold value th1, the transmission power of the communication unit that performs wireless communication with the base station is reduced while keeping the value according to the MCS in the communication unit. May be.

<Third Modification>
In the multi-system terminal 2, the transmission power of the first system communication unit 51 may be unintentionally decreased due to a significant decrease in the output voltage of the battery 40 or a failure of the first system communication unit 51. . In such a case, the transmission power of the first scheme communication unit 51 is set to the set value corresponding to the MCS used by the first scheme communication unit 51, that is, the normalized transmission power NSP. Becomes smaller than that converted into the transmission power per frequency bandwidth of the transmission signal transmitted from the antenna 21a. Therefore, in the first scheme base station 1a, the reception power of the transmission signal from the first scheme communication unit 51 becomes a value smaller than the reception power necessary for properly receiving the transmission signal, and the transmission signal is There is a possibility that it cannot be received properly. As a result, in the first system base station 1a, there may be many data reception errors from the first system communication unit 51.

  Therefore, in this modification, the transmission power reduction determination unit 35 determines whether or not the transmission power of the first scheme communication unit 51 is unintentionally reduced. And the offset addition part 36 will add an offset value with respect to a transmission power related value, if the transmission power reduction determination part 35 determines with the transmission power of the 1st system communication part 51 having decreased unintentionally. As a result, the rank of the MCS in the first method communication unit 51 is lowered, and the set value corresponding to the MCS for the transmission power of the first method communication unit 51 can be reduced. Therefore, the difference between the actual transmission power of the first method communication unit 51 and the set value corresponding to the MCS of the first method communication unit 51 can be reduced. As a result, even if the transmission power of the first scheme communication unit 51 is unintentionally reduced, the first scheme base station 1a can appropriately receive the transmission signal from the first scheme communication unit 51.

  For example, when the output voltage of the battery 40 becomes smaller than the threshold th3 that is smaller than the threshold th1 of the second modification, the transmission power reduction determination unit 35 intends the transmission power of the first scheme communication unit 51. It is determined that it has become smaller. As a result, even if the output voltage of the battery 40 is significantly reduced and the transmission power of the first method communication unit 51 is unintentionally reduced, the first method base station 1a A transmission signal can be received appropriately.

  Further, the transmission signal transmitted by the first method communication unit 51 is fed back to the transmission power reduction determination unit 35, and the transmission power reduction determination unit 35 periodically measures and measures the actual transmission power of the transmission signal. When the transmission power becomes a predetermined amount or more smaller than the set value corresponding to the MCS of the first method communication unit 51, it may be determined that the transmission power of the first method communication unit 51 has unintentionally decreased.

  In the present modification, when the battery 40 is charged and the output voltage of the battery 40 is equal to or greater than the threshold th4 equal to or greater than the threshold th3, the offset value with respect to the transmission power related value. Do not add.

  In the multi-method terminal 2, similarly to the first method communication unit 51, when the transmission power of the second method communication unit 52 is controlled to a set value according to the MCS in the second method communication unit 52. When the transmission power of the second method communication unit 52 is unintentionally reduced, the second method communication unit 52 is set in the same manner as when the set value corresponding to the MCS for the transmission power of the first method communication unit 51 is decreased. The set value corresponding to the MCS for the transmission power may be reduced. In this case, even if the transmission power of the second method communication unit 52 is unintentionally reduced, the actual transmission power of the second method communication unit 52 and the second method communication unit 52 The difference with the set value according to MCS can be reduced.

  Moreover, when the 1st system communication part 51 and the 2nd system communication part 52 are communicating simultaneously, since the output voltage of the battery 40 tends to fall, in this case, the output voltage of the battery 40 is a threshold value. The possibility of becoming smaller than the value th3 increases. Therefore, when only one of the first method communication unit 51 and the second method communication unit 52 is communicating, without determining whether the output voltage of the battery 40 has become smaller than the threshold th3, When the first method communication unit 51 and the second method communication unit 52 communicate at the same time, it may be determined whether the output voltage of the battery 40 has become smaller than the threshold value th3.

  Further, not only a multi-method terminal 2 capable of communicating using a plurality of wireless communication methods, but also a single-method terminal such as a communication terminal communicating using only WiMAX, performs communication that performs wireless communication with a base station. When the transmission power of the communication unit is controlled to a set value corresponding to the MCS in the communication unit, when the transmission power of the communication unit is unintentionally reduced, the MCS for the transmission power of the communication unit The set value according to the value may be reduced.

<Fourth Modification>
In the above example, as the transmission power related value for the first method communication unit 51, the value of the transmission power of the first method communication unit 51 when transmitting the transmission power related value is adopted. You may employ | adopt the margin (headroom) about the transmission power of the said 1st system communication part 51 at the time of transmitting the said transmission power related value. That is, the transmission power related value for the first scheme communication unit 51 is transmitted from the maximum transmission power SPmax of the first scheme communication unit 51, and the transmission power of the first scheme communication unit 51 when transmitting the transmission power related value. A value obtained by subtracting.

  In this case, in the first scheme base station 1a, the MCS determination unit 112 displays the headroom indicated by the transmission power related value notified from the first scheme communication unit 51 as the maximum transmission power SPmax of the first scheme communication unit 51. The value obtained by subtracting from the transmission power of the first method communication unit 51 when the first method communication unit 51 transmits the transmission power related value (the frequency bandwidth of the related value notification signal including the transmission power related value) Per transmission power). Then, the MCS determination unit 112 converts the obtained transmission power into the transmission power per bandwidth of the uplink use frequency band allocated to the multi-modal terminal 2 by the radio resource allocation unit 111 and performs the transmission power prediction described above. The value SP is obtained.

  When headroom is adopted as the transmission power related value for the first scheme communication unit 51, the offset adding unit 36 is a negative offset with respect to the transmission power related value of the first scheme base station 1a. The value will be added. As a result, the transmission power predicted value SP obtained as described above increases, and therefore the transmission power margin HR decreases. As a result, the MCS rank of the first method communication unit 51 is lowered.

  Further, the maximum transmission power SPmax of the first scheme communication unit 51 may be adopted as the transmission power related value for the first scheme communication unit 51. In this case, the offset adding unit 36 adds a negative offset value to the maximum transmission power SPmax of the first scheme base station 1a. In addition to the transmission power related value, the first scheme communication unit 51 notifies the first scheme base station 1a of the transmission power or headroom of the first scheme communication unit 51 at that time. Accordingly, the first scheme base station 1a can determine the transmission power margin HR in the same manner as described above. When a negative offset value is added to the maximum transmission power SPmax of the first system base station 1a, the transmission power margin HR is reduced. As a result, the MCS rank of the first method communication unit 51 is lowered.

  As described above, for example, the first mode communication unit 51 that communicates using WiMAX, for example, connects the maximum transmission power SPmax of itself to the network via the first mode base station 1a. The station 1a is notified. Accordingly, the first scheme communication unit 51 cannot notify the first scheme base station 1a of the maximum transmission power SPmax to which the offset value is added in a state where it is connected to the network. As described above, when the first method communication unit 51 notifies the first method base station 1a of its maximum transmission power SPmax only when connecting to the network, the first method communication unit 51 When the connection with the network is once disconnected and the network is connected again, the maximum transmission power SPmax to which the offset value is added is notified to the first system base station 1a.

  On the other hand, when the first method communication unit 51 can regularly notify the first method base station 1a of its maximum transmission power SPmax, the first method communication unit 51 establishes connection with the network. Without disconnection, the first transmission base station 1a can be notified of the maximum transmission power SPmax to which the offset value has been added.

  Further, when the offset value is added to the transmission power related value for the second method communication unit 52 so that the MCS rank in the second method communication unit 52 is lowered, The headroom may be employed, or the maximum transmission power may be employed.

<Fifth Modification>
In the above example, the offset value added to the transmission power related value is a fixed value, but the offset value may be changed. The operation of the multi-modal terminal 2 when changing the offset value will be described below using the flowchart of FIG.

  In the flowchart shown in FIG. 6, when it is determined in step s8 that the transmission power of the first scheme communication unit 51 needs to be reduced, in step s9, the offset adding unit 36 stores the MCS− stored in the storage unit 37. Using the received power table 37a, the MCS of the first scheme communication unit 51 calculates an offset value that will be lowered by one rank from the current rank. Specifically, the offset adding unit 36 first corresponds to the MCS whose rank is one lower than the MCS from the normalized desired received power NRP associated with the current MCS of the first scheme communication unit 51. A value obtained by subtracting the normalized desired received power NRP attached is obtained. Then, the offset adding unit 36 uses the obtained value as a value per bandwidth of the frequency band used when the first scheme communication unit 51 transmits the transmission power related value, that is, per frequency bandwidth of the related value notification signal. The MCS of the first method communication unit 51 uses the obtained value as an offset value that will be lowered by one from the current rank. The offset adding unit 36 adds the offset value obtained in this way to the transmission power related value.

  After that, when the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 still exceeds the allowable value, or the transmission power in the target multi-method terminal 2 as a whole still has the allowable value If it is exceeded and step s8 is executed again, in step s9, the offset adding unit 36 reduces the offset value by the amount that the MCS rank of the first scheme communication unit 51 will be further lowered by one. increase. Specifically, the offset adding unit 36 has a rank higher than that of the MCS from the normalized desired received power NRP associated with the MCS (current MCS) that has been lowered by one rank by the previous execution of step s9. A value obtained by subtracting the normalized desired received power NRP associated with the lower MCS is obtained. Then, the offset addition unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal, and increases the offset value by the value obtained thereby.

  After that, when the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 still exceeds the allowable value, or the transmission power in the target multi-method terminal 2 as a whole still exceeds the allowable value. If step s8 is executed again, in step s9, the offset adder 36 similarly reduces the offset value by one more in the MCS rank of the first scheme communication unit 51. Increase it as much as possible. Thereafter, the target multi-method terminal 2 operates.

  Thus, until the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 becomes less than the allowable value, or the transmission power of the target multiple method terminal 2 as a whole is an allowable value. By increasing the offset value so that the MCS rank of the first method communication unit 51 is lowered one by one until the following, the MCS rank of the first method communication unit 51 is prevented from being lowered more than necessary. Can do.

  Note that the offset value may be adjusted in a manner different from the above. For example, the offset value may be adjusted so that an appropriate MCS is determined using the binary search method. The offset value adjustment method in this case will be described below.

  When the transmission power reduction determination unit 35 determines that the transmission power of the first scheme communication unit 51 needs to be reduced, the offset addition unit 36 uses the MCS-reception power table 37 a stored in the storage unit 37. The offset value that the MCS rank of the first method communication unit 51 will drop to an intermediate rank between the current rank and the lowest rank is calculated. Specifically, the offset adding unit 36 first determines the intermediate rank between the rank of the MCS and the lowest rank from the normalized desired received power NRP associated with the current MCS of the first method communication unit 51. A value obtained by subtracting the normalized desired received power NRP associated with the MCS is obtained. Then, the offset addition unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal. Then, the offset adding unit 36 sets the obtained value as an offset value that will cause the MCS rank of the first method communication unit 51 to drop to an intermediate rank between the current rank and the lowest rank. The offset adding unit 36 adds the offset value obtained in this way to the transmission power related value. Thereby, the rank of MCS of the 1st system communication part 51 is changed.

  After the MCS rank in the first method communication unit 51 is changed, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 still exceeds the allowable value, or If the transmission power in the entire target multi-method terminal 2 still exceeds the allowable value, the offset adding unit 36 determines that the MCS rank of the first method communication unit 51 is the current rank (rank after change) and the previous time. The offset value that will be lowered to the middle rank between the lower rank of the two ranks of the MCS used in the calculation of the offset value is obtained. Specifically, the offset adder 36 calculates the normalization request associated with the intermediate rank MCS from the normalization desired received power NRP associated with the current MCS of the first method communication unit 51. A value obtained by subtracting the received power NRP is obtained. Then, the offset addition unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal. Then, the offset adding unit 36 adds the obtained value to the current offset value, and sets the obtained value as a new offset value. This new offset value is an intermediate rank between the current rank and the lower rank of the two MCS ranks used in the previous calculation of the offset value for the MCS rank of the first method communication unit 51. It will be the offset value that will fall to. The offset adding unit 36 adds the new offset value obtained in this way to the transmission power related value.

  On the other hand, after the MCS rank of the first method communication unit 51 is changed, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is less than the allowable value. Alternatively, if the transmission power of the entire target multi-method terminal 2 is equal to or less than the allowable value, the offset adding unit 36 determines that the MCS rank of the first method communication unit 51 is the current rank (rank after change). Then, an offset value that will increase to an intermediate rank between the higher rank of the two MCS ranks used in the previous offset value calculation is obtained. Specifically, the offset adding unit 36 uses the normalization desired received power NRP associated with the current MCS of the first scheme communication unit 51 to the normalization desired associated with the intermediate rank MCS. A value obtained by subtracting from the received power NRP is obtained. Then, the offset addition unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal. Then, the offset adding unit 36 subtracts the obtained value from the current offset value, and sets the obtained value as a new offset value. This offset value increases the rank of the MCS of the first method communication unit 51 to an intermediate rank between the current rank and the higher rank of the two MCS ranks used in the previous calculation of the offset value. Will be the offset value. The offset adding unit 36 adds the offset value obtained in this way to the transmission power related value.

  Thereafter, the target multi-method terminal 2 operates in the same manner, and for the MCS of the first method communication unit 51, the higher rank of the current rank and the two ranks of MCS used in the previous calculation of the offset value. If there is no intermediate rank between the current rank and the lower rank of the two MCS ranks used in the previous calculation of the offset value, the first method communication unit 51 This completes the adjustment of the MCS rank.

  Thus, by determining the optimum MCS using the binary search method, it is possible to suppress the MCS rank of the first method communication unit 51 from being lowered more than necessary.

  Further, the offset value may be adjusted in a manner different from the above. For example, the offset value may be adjusted so that the rank of the MCS of the first method communication unit 51 is once lowered to the lowest rank and then increased one by one. The offset value adjustment method in this case will be described below.

  When the transmission power reduction determination unit 35 determines that the transmission power of the first scheme communication unit 51 needs to be reduced, the offset addition unit 36 uses the MCS-reception power table 37 a stored in the storage unit 37. The offset value that the MCS rank of the first method communication unit 51 will be lowered to the lowest rank is calculated. Specifically, the offset addition unit 36 calculates the normalized desired received power associated with the lowest rank MCS from the normalized desired received power NRP associated with the current MCS of the first scheme communication unit 51. The value obtained by subtracting NRP is obtained. Then, the offset addition unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal. Then, the offset addition unit 36 sets the obtained value as an offset value that will cause the MCS rank of the first method communication unit 51 to drop to the lowest rank. The offset adding unit 36 adds the offset value obtained in this way to the transmission power related value. Thereby, the rank of the MCS of the first method communication unit 51 becomes the lowest rank.

  After the MCS rank in the first method communication unit 51 becomes the lowest rank, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 still exceeds the allowable value Therefore, the lowest rank of the MCS rank of the first method communication unit 51 is maintained. Further, when the transmission power of the entire target multi-method terminal 2 still exceeds the allowable value, the communication of either the first method communication unit 51 or the second method communication unit 52 is disconnected.

  On the other hand, after the MCS rank of the first method communication unit 51 becomes the lowest rank, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is less than the allowable value. In some cases, or when the transmission power of the entire target multi-method terminal 2 is less than or equal to the allowable value, the offset adding unit 36 sets the offset value, and the MCS rank of the first method communication unit 51 is the current rank ( Decrease by the amount that will rise from the lowest rank to the next higher rank. Specifically, the offset adding unit 36 ranks the normalized desired received power NRP associated with the current MCS (lowest rank MCS) of the first scheme communication unit 51 one rank higher than the MCS. A value obtained by subtracting from the normalized desired received power NRP associated with the MCS is obtained. Then, the offset adding unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal, and decreases the offset value by the value obtained thereby.

  The offset addition unit 36 decreases the offset value, and then the interference intensity that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 exceeds the allowable value, or the target multiple method terminal If the transmission power of the whole 2 exceeds the allowable value, the offset value is returned to the value before the decrease, and the rank of the MCS of the first method communication unit 51 is set to the rank one before the current rank. To be.

  On the other hand, after the offset addition unit 36 decreases the offset value, the intensity of interference that the transmission signal of the first method communication unit 51 gives to the reception signal of the second method communication unit 52 is less than the allowable value, or If the transmission power of the target multi-method terminal 2 as a whole is less than the allowable value, the offset value is decreased by an amount that the rank of the MCS of the first method communication unit 51 will rise to a higher rank. Let Specifically, the offset addition unit 36 associates the normalized desired received power NRP associated with the current MCS of the first scheme communication unit 51 with the MCS that is one rank higher than the MCS. A value subtracted from the normalized desired received power NRP is obtained. Then, the offset adding unit 36 converts the obtained value into a value per frequency bandwidth of the related value notification signal, and decreases the offset value by the value obtained thereby.

  Thereafter, the target multi-method terminal 2 operates in the same manner.

  Thus, the first method communication unit 51 determines the optimum MCS by lowering the MCS rank of the first method communication unit 51 to the lowest rank and then increasing the rank one by one. It can suppress that the rank of 51 MCS falls more than necessary.

  In addition, when the offset value is added to the transmission power related value for the second scheme communication unit 52 so that the rank of the MCS in the second scheme communication unit 52 is lowered, the offset value as described above. The optimum MCS may be determined while adjusting the above.

<Other variations>
In the above example, the multi-method terminal 2 can use two wireless communication methods, but may use three or more wireless communication methods. For example, the multi-system terminal 2 may be able to use three wireless communication systems, WiMAX, W-CDMA, and WiFi.

  In the case where the multi-method terminal 2 can use three or more wireless communication methods, at least two of the communication units that perform wireless communication using the plurality of wireless communication methods, respectively. 6 and 7, when the communication unit simultaneously communicates, the transmission power of the communication unit that greatly interferes with other communication units in the at least two communication units is transferred to the MCS in the communication unit. In the base station that communicates with the communication unit whose transmission power is reduced while keeping the intensity of interference given to the other communication unit below the allowable value by reducing the value according to the corresponding value, transmission from the communication unit The signal can be properly received. Further, by reducing the transmission power of at least one communication unit in the at least two communication units to a value corresponding to the MCS in the communication unit, the transmission power of the multi-modal terminal 2 as a whole is suppressed to an allowable value or less. On the other hand, in a base station that communicates with a communication unit whose transmission power is reduced, a transmission signal from the communication unit can be appropriately received.

  In the above example, the first mode base station 1a sets both the modulation scheme and the coding rate used by the first mode communication unit 51 of the multi-mode terminal 2 to the transmission power margin for the first mode communication unit 51. The multi-mode terminal 2 determines the transmission power of the first mode communication unit 51 according to the modulation scheme and coding rate notified from the first mode base station 1a. . However, in the modulation scheme and coding rate used by the first scheme communication unit 51, one is fixed, and only the other is used by the first scheme base station 1a as the transmission power margin HR for the first scheme communication unit 51. Based on the adaptive control, the multi-method terminal 2 may determine the transmission power of the first-method communication unit 51 according to the other notified from the first-method base station 1a.

  The first method base station 1a adaptively controls the modulation method of the first method communication unit 51, and the plurality of method terminals 2 of the first method communication unit 51 according to the modulation method notified from the first method base station 1a. When determining the transmission power, in the above description, “MCS” may be replaced with “modulation method”. Accordingly, when it is necessary to reduce the transmission power of the first scheme communication unit 51, the transmission power of the first scheme communication unit 51 is reduced by adding the offset value to the transmission power related value. It can be made small while setting the value according to the modulation method used by the method communication unit 51. Further, when the transmission power of the first method communication unit 51 is unintentionally reduced, the actual transmission power of the first method communication unit 51 is added by adding an offset value to the transmission power related value, The difference with the set value according to the modulation method can be reduced.

  Also, the first scheme base station 1a adaptively controls the coding rate of the first scheme communication unit 51, and the multiple scheme terminal 2 is the first scheme according to the coding rate notified from the first scheme base station 1a. When determining the transmission power of the communication unit 51, “MCS” may be replaced with “coding rate” in the above description. Accordingly, when it is necessary to reduce the transmission power of the first scheme communication unit 51, the transmission power of the first scheme communication unit 51 is reduced by adding the offset value to the transmission power related value. It can be made small while setting the value according to the coding rate used by the system communication unit 51. Further, when the transmission power of the first method communication unit 51 is unintentionally reduced, the actual transmission power of the first method communication unit 51 is added by adding an offset value to the transmission power related value, The difference from the set value corresponding to the coding rate can be reduced.

  In the above description, the case where the present invention is applied to a wireless communication system including a base station and a communication terminal has been described. However, the present invention is not limited to this, and the present invention includes a plurality of wireless communication devices. Any wireless communication system can be applied.

DESCRIPTION OF SYMBOLS 1a 1st system base station 1b 2nd system base station 2 Communication terminal 10 Wireless communication part 33 Transmission power determination part 34 Transmission power related value acquisition part 35 Transmission power reduction determination part 36 Offset addition value 40 Battery 51 1st system communication part 52 Second system communication unit 100 Wireless communication system 112 MCS determination unit

Claims (14)

A communication unit that performs wireless communication with a communication partner device;
A transmission power determination unit that determines transmission power of the communication unit according to at least one notified from the communication partner device among the modulation scheme and coding rate in the communication unit;
An acquisition unit for acquiring a transmission power related value related to the transmission power of the communication unit, which is notified from the communication unit to the communication counterpart device;
A determination unit for determining whether it is necessary to reduce the transmission power of the communication unit;
When the determination unit determines that the transmission power of the communication unit needs to be reduced, the wireless communication device includes an offset addition unit that adds an offset value to the transmission power related value. The wireless communication device according to claim 1,
A second communication unit that communicates using a wireless communication method different from the communication unit;
In the case where the communication unit and the second communication unit communicate at the same time, the determination unit is configured to perform communication when the intensity of interference that the transmission signal of the communication unit gives to the reception signal of the second communication unit exceeds an allowable value. A wireless communication apparatus that determines that the transmission power of a part needs to be reduced. The wireless communication device according to claim 1,
A second communication unit that communicates using a wireless communication method different from the communication unit;
In the case where the communication unit and the second communication unit communicate simultaneously, the determination unit needs to reduce the transmission power of the communication unit when the transmission power of the entire wireless communication device exceeds an allowable value. A wireless communication device for determining. A wireless communication device according to any one of claims 2 and 3,
The said offset addition part is a radio | wireless communication apparatus which does not add the said offset value with respect to the said transmission power related value, when the said communication part and the said 2nd communication part stop communicating simultaneously. A wireless communication device according to any one of claims 1 to 4, wherein
A battery for generating a power source for the wireless communication device;
The determination unit is a wireless communication device that determines that the transmission power of the communication unit needs to be reduced when the output voltage of the battery becomes smaller than a threshold value. The wireless communication unit according to claim 1,
A second communication unit that communicates using a wireless communication method different from the communication unit;
A battery for generating a power source of the wireless communication device,
The determination unit is a wireless communication device that determines that the transmission power of the communication unit needs to be reduced when the output voltage of the battery becomes smaller than a threshold value. A communication unit that performs wireless communication with a communication partner device;
A transmission power determination unit that determines transmission power of the communication unit according to at least one notified from the communication partner device among the modulation scheme and coding rate in the communication unit;
An acquisition unit for acquiring a transmission power related value related to the transmission power of the communication unit, which is notified from the communication unit to the communication counterpart device;
A determination unit that determines whether or not the transmission power of the communication unit is unintentionally reduced;
A wireless communication apparatus, comprising: an offset addition unit that adds an offset value to the transmission power related value when the determination unit determines that the transmission power of the communication unit has decreased unintentionally. The wireless communication device according to claim 7,
A battery for generating a power source for the wireless communication device;
The said determination part is a radio | wireless communication apparatus which determines with the transmission power of the said communication part having decreased unintentionally when the output voltage of the said battery becomes smaller than a threshold value. A wireless communication device according to any one of claims 5, 6 and 8,
The offset adding unit does not add the offset value to the transmission power related value when the output voltage of the battery is equal to or higher than a second threshold value equal to or greater than the threshold value. Communication device. A wireless communication device according to any one of claims 1 to 9,
The transmission power related value indicates the transmission power of the communication unit when the communication unit transmits the transmission power related value,
The wireless communication apparatus, wherein the offset value is a positive value. A wireless communication device according to any one of claims 1 to 9,
The transmission power related value indicates a margin of transmission power in the communication unit when the communication unit transmits the transmission power related value,
The wireless communication apparatus, wherein the offset value is a negative value. A wireless communication device according to any one of claims 1 to 9,
The transmission power related value indicates the maximum transmission power of the communication unit,
The wireless communication apparatus, wherein the offset value is a negative value. A first wireless communication device;
A second wireless communication device that performs wireless communication with the first wireless communication device;
The first wireless communication device is:
A first communication unit that performs wireless communication with the second wireless communication device;
A transmission power determination unit that determines transmission power of the first communication unit according to at least one of the modulation scheme and coding rate in the first communication unit notified from the second wireless communication device;
An acquisition unit for acquiring a transmission power related value related to the transmission power of the first communication unit, which is notified from the first communication unit to the second wireless communication device;
A determination unit for determining whether it is necessary to reduce the transmission power of the first communication unit;
An offset addition unit that adds an offset value to the transmission power related value when the determination unit determines that the transmission power of the first communication unit needs to be reduced;
The second wireless communication device is
A second communication unit for performing wireless communication with the first wireless communication device;
A determination unit that determines at least one of a modulation scheme and a coding rate in the first communication unit based on the transmission power-related value received in the second communication unit;
The second communication unit is configured to notify the first wireless communication device of at least one of a modulation scheme and a coding rate in the first communication unit, which is determined by the determination unit based on the transmission power related value. Communications system. A first wireless communication device;
A second wireless communication device that performs wireless communication with the first wireless communication device;
The first wireless communication device is:
A first communication unit that performs wireless communication with the second wireless communication device;
A transmission power determination unit that determines transmission power of the first communication unit according to at least one of the modulation scheme and coding rate in the first communication unit notified from the second wireless communication device;
An acquisition unit for acquiring a transmission power related value related to the transmission power of the first communication unit, which is notified from the first communication unit to the second wireless communication device;
A determination unit that determines whether or not the transmission power of the communication unit is unintentionally reduced;
When the determination unit determines that the transmission power of the first communication unit has decreased unintentionally, an offset addition unit that adds an offset value to the transmission power related value,
The second wireless communication device is
A second communication unit for performing wireless communication with the first wireless communication device;
A determination unit that determines at least one of a modulation scheme and a coding rate in the first communication unit based on the transmission power-related value received in the second communication unit;
The second communication unit is configured to notify the first wireless communication device of at least one of a modulation scheme and a coding rate in the first communication unit, which is determined by the determination unit based on the transmission power related value. Communications system.

Images