JP3898671B2 - Wireless device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio apparatus using Orthogonal Frequency Division Multiplexing (OFDM) modulation.
[0002]
[Prior art]
When OFDM modulation is used, the modulated wave becomes a multicarrier signal in the frequency domain. In the transmission waveform of the multicarrier signal, the difference between the average power and the peak power becomes large. When amplifying such a signal, it is generally necessary to use a low-efficiency class power amplifier such as Class A, Class AB, or Class B, resulting in low power efficiency.
[0003]
Therefore, it is known that by controlling the drain or collector voltage of the power amplifier based on the amplitude data, a power amplifier of a high efficiency class such as class C can be used to improve the power efficiency (for example, Patent Document 1). reference).
[0004]
In the technique used in Patent Document 1, only the phase change of the OFDM modulation signal is input to the input of the power amplifier, so that the difference between the average power and the peak power of the input does not increase, and the amplitude variation of the signal is reduced to the drain voltage. Alternatively, the dynamic range of the output is changed by entering the collector voltage (see, for example, Non-Patent Document 1 and Non-Patent Document 2).
[0005]
[Patent Document 1]
JP 2000-269920 A (first page, FIG. 1)
[0006]
[Non-Patent Document 1]
Steve C. Cripps, “RF power amplifiers for wireless communications”, P.246-247, Artech House microwave library, ISBN 0-89006-989-1
[0007]
[Non-Patent Document 2]
Lawrence E. Larson, “RF and microwave circuit design for wireless communications”, p. 81-87, Artech House, INC, ISBN 0-89006-818-6.
[0008]
[Problems to be solved by the invention]
In such a conventional technique, an amplitude control circuit for correcting the drain or collector voltage to the power amplifier with the amplitude data of the IFFT modulation signal is provided. Since this amplitude control circuit becomes a large-scale one requiring a large correction value table, there has been a problem that the circuit scale of the wireless device is greatly increased.
[0009]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wireless device capable of reducing power consumption while suppressing an increase in circuit scale. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a setting means for selectively setting an OFDM (Orthogonal Frequency Division Multiplex) modulation mode and a single carrier modulation mode, and OFDM modulation of transmission data at the time of setting the OFDM modulation mode, A modulation means for single-carrier modulating the transmission data at the time of setting the single carrier modulation mode, and amplifying the output signal of the modulation means at a first operating point with relatively low power efficiency at the time of setting the OFDM modulation mode; Means for amplifying at a second operating point with relatively high power efficiency when setting the single carrier modulation mode; means for receiving a transmission power control signal designating transmission power; and 1) The transmission power specified by the transmission power control signal is less than a threshold, and the transmission data is of the first type (2) When the transmission power specified by the transmission power control signal is less than a threshold and the transmission data is of the second type, the single carrier modulation mode is (3). The single carrier modulation mode is set when the transmission power specified by the transmission power control signal is greater than or equal to a threshold value.
[0011]
By taking such means, when the transmission power specified by the transmission power control signal is less than the threshold and the transmission data is of the first type, multi-carrier transmission by the OFDM modulation is performed, When the transmission power specified by the transmission power control signal is less than the threshold and the transmission data is the second type, or when the transmission power specified by the transmission power control signal is greater than or equal to the threshold, the single by single carrier modulation Switching to carrier transmission is performed, and the amplification of the output signal of the modulation means is performed at the first operating point with relatively low power efficiency when multicarrier transmission is performed. During carrier transmission, switching is performed so as to be performed at the second operating point with relatively high power efficiency.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
(First embodiment)
FIG. 1 is a block diagram illustrating a configuration of a wireless device according to the first embodiment.
The wireless device according to the first embodiment includes a serial / parallel (S / P) converter 1, selectors 2-1, 2-2,..., 2-n, null value generators 3-1, 3-2,. -n, inverse fast Fourier transformer (IFFT) 4, parallel / serial (P / S) converter 5, digital / analog (D / A) converter 6, frequency converter 7, transmission power amplifier (transmission PA) 8 , Antenna 9, modulation mode switching unit 10, and protocol control unit 11.
[0014]
The S / P converter 1 rearranges the serially input digital data into parallel data having the same width as the window width of the IFFT 4. The S / P converter 1 has a function of outputting data only to a signal line corresponding to one subchannel under the control of the modulation mode switching unit 10. The output of the S / P converter 1 is input to the IFFT 4 via the selectors 2-1, 2-2,. The selectors 2-1, 2-2,..., 2-n are provided in the same number as the number n of subcarriers in OFDM. Each of the selectors 2-1, 2-2,..., 2-n receives data transmitted on one subcarrier. All the null value data output from the null value generators 3-1, 3-2,..., 3-n are input to the selectors 2-1, 2-2,. The selectors 2-1, 2-2,..., 2-n, under the control of the modulation mode switching unit 10, output the S / P converter 1 and null value generators 3-1, 3-2,. Either n output is selected and output to IFFT4.
[0015]
The IFFT 4 performs inverse FFT (fast Fourier transform) on the parallel data given from the selectors 2-1, 2-2,. The P / S converter 5 converts the parallel data output from the IFFT 4 into serial data in accordance with the time domain.
[0016]
The D / A converter 6 converts the serial data output from the P / S converter 5 into an analog signal. The frequency converter 7 converts the analog signal that is the output of the D / A converter 6 to a carrier frequency band. The transmission PA 8 amplifies the output signal of the frequency converter 7 to a power level necessary for wireless transmission. The transmission PA 8 has a function of changing the operating point under the control of the modulation mode switching unit 10. The antenna 9 wirelessly transmits the output signal of the transmission PA8.
[0017]
The modulation mode switching unit 10 acquires information on the progress of the protocol from the protocol control unit 11, and sets the modulation mode to the multicarrier mode or the single carrier mode based on this information. The modulation mode switching unit 10 determines whether the modulation mode is set to the multicarrier mode or the single carrier mode, the S / P converter 1, the selectors 2-1, 2-2,. Switches the operation of PA8. The protocol control unit 11 selects an appropriate transmission format according to a request from a user or a wireless terminal application, or another wireless device that performs wireless communication (for example, a wireless device used by a base station or another user). Performs communication related to control.
[0018]
Next, the operation of the wireless device configured as described above will be described.
The radio apparatus according to the first embodiment basically performs radio communication using the OFDM modulation scheme. In such a state, the modulation mode switching unit 10 sets the multicarrier mode as the modulation mode.
[0019]
In the multi-carrier mode, the S / P converter 1 rearranges the input digital data into parallel data having the same width as the window width of the IFFT 4 and outputs the parallel data. The selectors 2-1, 2-2,..., 2-n select the output data of the S / P converter 1, respectively. Thus, in the multicarrier mode, OFDM modulation is performed by the S / P converter 1, IFFT 4, P / S converter 5, D / A converter 6 and frequency converter 7 according to a well-known procedure. The signal output from the frequency converter 7 is amplified by the transmission PA 8 and then wirelessly transmitted from the antenna 9.
[0020]
At this time, the signal input to the transmission PA 8 is a multicarrier signal having a spectrum as shown in FIG. 2 in the frequency domain. For this reason, the difference between the average power and the peak power is large. Therefore, in the multicarrier mode, the transmission PA 8 operates at an operating point that is in the low efficiency class. Thereby, it is possible to amplify a multicarrier signal as shown in FIG. 2 with high quality.
[0021]
By the way, when a wireless device is communicating with a base station, such as a cellular communication system or a wireless LAN, first, for example, to establish a connection between the base station and the wireless device, the type of channel used, transmission rate, format, etc. Exchange of control information such as Such control information and information such as personal identification number and key information that the user requests to transmit through the base station may require a low transmission rate. Other information that requires a low transmission rate includes the location registration value of the wireless device, terminal information data to be transmitted at the time of outgoing / incoming calls, and data without error correction. Or data (regardless of control data or user data) such as low-speed packet data is assumed.
[0022]
The modulation mode switching unit 10 monitors the progress of the protocol based on the information output from the protocol control unit 11, and at the timing of transmitting the kind of data having a low necessary transmission rate as described above, Set the carrier mode. It should be noted that the designer and user of the radio apparatus may determine appropriately which data is to be set when the single carrier mode is set. For example, the modulation mode can be switched by referring to the table showing the relationship between the data type and the modulation mode by the modulation mode switching unit 10.
[0023]
In the single carrier mode, the modulation mode switching unit 10 selects one to be used for data transmission from a plurality of subcarriers. The subcarrier selected here may be any one of a plurality of subcarriers assigned for OFDM transmission. Further, if a subcarrier usable in the single carrier mode is limited by the communication system, any one of subcarriers permitted to be used by the communication system may be used. If only one subcarrier that can be used in the single carrier mode is designated by the communication system, that subcarrier may be used.
[0024]
The S / P converter 1 outputs the input digital data only to the signal line corresponding to one subcarrier designated from the modulation mode switching unit 10. In the selectors 2-1, 2-2,..., 2-n, only one corresponding to the one subcarrier described above selects the output signal of the S / P converter 1, and the others are the null value generator 3-1. , 3-2 ..., 3-n selects all null data output. Thus, in the single carrier mode, a signal having data on only one subcarrier is output from the A / D converter 6. The output signal of the A / D converter 6 is up-converted by the frequency converter 7, amplified by the transmission PA 8, and wirelessly transmitted from the antenna 9.
[0025]
At this time, the signal input to the transmission PA 8 is a single carrier signal having a spectrum as shown in FIG. 3 in the frequency domain. For this reason, the difference between the average power and the peak power is not so large, and the transmission PA 8 can amplify the transmission PA 8 without much deterioration in quality even when operating in the high efficiency class. Therefore, in the single carrier mode, the transmission PA 8 operates at an operating point that is a high efficiency class.
[0026]
As described above, the radio apparatus according to the first embodiment basically realizes data transmission at a high rate using OFDM modulation. However, when the transmission data requires a low transmission rate, a single carrier signal is transmitted and the transmission PA 8 is operated in the high efficiency class. This makes it possible to reduce power consumption compared to the case where the transmission PA 8 is always operated in the low efficiency class. Furthermore, the radio apparatus according to the first embodiment generates a single carrier signal using one of a plurality of subcarriers used for OFDM modulation. For this reason, most of the circuits for OFDM modulation can be used for the generation of a single carrier signal, and the increase in circuit scale compared to a radio apparatus that always performs OFDM modulation can be suppressed small.
[0027]
(Second Embodiment)
FIG. 4 is a block diagram illustrating a configuration of a wireless device according to the second embodiment. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.
The radio apparatus of the second embodiment includes an S / P converter 1, selectors 2-1, 2-2,..., 2-n, null value generators 3-1, 3-2,. A P / S converter 5, a D / A converter 6, a frequency converter 7, a transmission PA 8, an antenna 9, a protocol control unit 11, a TPC receiver 21, and a modulation mode switching unit 22 are included.
[0028]
That is, the wireless device of the second embodiment includes a modulation mode switching unit 22 instead of the modulation mode switching unit 10 in the wireless device of the first embodiment, and a new TPC receiver 21.
[0029]
The TPC receiver 21 receives a TPC (Transmission Power Control) signal transmitted from a base station (not shown). The TPC signal is a signal that instructs the base station to increase or decrease the transmission power from the base station.
[0030]
The modulation mode switching unit 22 obtains information on the progress of the protocol from the protocol control unit 11 and also obtains instruction information in the TPC signal from the TPC receiver 21 and sets the modulation mode based on these information to the multicarrier. Set to mode or single carrier mode. The modulation mode switching unit 22 selects the S / P converter 1, the selectors 2-1, 2-2,..., 2-n and the transmission depending on whether the modulation mode is set to the multicarrier mode or the single carrier mode. Switches the operation of PA8.
[0031]
Next, the operation of the wireless device configured as described above will be described.
The wireless device that has received the TPC signal must increase or decrease the output of the transmission PA 8 in accordance with the instruction of the TPC signal. Therefore, a TPC control unit (not shown) changes the gain of the transmission PA 8 based on the TPC signal received by the TPC receiver 21.
[0032]
When the gain of the transmission PA 8 is increased because a large transmission power is required by the TPC signal, the power consumption becomes very large when the transmission PA 8 is operating in the low efficiency class.
[0033]
The modulation mode switching unit 22 switches the modulation mode according to the type of transmission data in the same manner as the modulation mode switching unit 10 in the first embodiment, but transmission power equal to or higher than the threshold is requested by the TPC signal. If it is determined, the modulation mode is set to the single carrier mode regardless of the type of transmission data. Note that the operation states in the single carrier mode and the multicarrier mode are the same as those in the first embodiment.
[0034]
Thus, in a situation where it is necessary to perform transmission with a transmission power equal to or higher than a threshold value, a single carrier signal with a large power having a spectrum as shown in FIG. 5 in the frequency domain is obtained. For this reason, even if the transmission PA 8 is operating in the high efficiency class, it is possible to amplify the transmission PA 8 without much deterioration in quality.
[0035]
As described above, the radio apparatus according to the second embodiment basically realizes data transmission at a high rate using OFDM modulation. However, if the data to be transmitted has a low required transmission rate or needs to be transmitted with a transmission power equal to or higher than a threshold value, a single carrier signal is transmitted and the transmission PA 8 is operated in a high efficiency class. This makes it possible to reduce power consumption compared to the case where the transmission PA 8 is always operated in the low efficiency class. Furthermore, the radio apparatus according to the second embodiment generates a single carrier signal using one of a plurality of subcarriers used for OFDM modulation. For this reason, most of the circuits for OFDM modulation can be used for the generation of a single carrier signal, and the increase in circuit scale compared to a radio apparatus that always performs OFDM modulation can be suppressed small.
[0036]
In addition, when it is necessary to perform transmission with transmission power equal to or higher than the threshold value, the communication quality between the wireless device and the base station is deteriorated. In such a situation, the second embodiment portable radio apparatus operates the transmission PA 8 in the high efficiency class, so that transmission can be performed with sufficiently large transmission power, and information can be transmitted reliably. .
[0037]
(Third embodiment)
FIG. 6 is a block diagram illustrating a configuration of a wireless device according to the third embodiment.
The wireless device according to the third embodiment includes an S / P converter 1, an IFFT 4, a P / S converter 5, a D / A converter 6, a transmission PA 8, an antenna 9, a protocol control unit 11, and signal switchers 31 and 32. In addition, a frequency converter 33 and a modulation mode switching unit 34 are included.
[0038]
That is, the wireless device of the third embodiment includes a frequency converter 33 instead of the frequency converter 7 in the wireless device of the first embodiment, and includes a modulation mode switching unit 34 instead of the modulation mode switching unit 10. . Further, the wireless device of the third embodiment includes selectors 2-1, 2-2,..., 2-n and null value generators 3-1, 3-2,..., 3-n in the wireless device of the first embodiment. The output of the S / P converter 1 is directly input to the IFFT 4. Furthermore, the radio apparatus according to the third embodiment newly includes signal switchers 31 and 32.
[0039]
The signal switching units 31 and 32 operate in conjunction with the control of the modulation mode switching unit 34, input digital data to the S / P converter 1, and output the output of the P / S converter 5 to the D / A. The path for inputting to the converter 6 and the path for inputting digital data to the D / A converter 6 without passing through the IFFT 4 and the P / S converter 5 are switched.
[0040]
The frequency converter 33 frequency-converts the analog signal that is the output of the D / A converter 6 to the carrier frequency band for OFDM or the carrier frequency band for single carrier.
[0041]
The modulation mode switching unit 34 acquires information on the progress of the protocol from the protocol control unit 11 and sets the modulation mode to the multicarrier mode or the single carrier mode based on this information. The modulation mode switching unit 34 switches the operations of the transmission PA 8, the signal switchers 31 and 32, and the frequency converter 33 depending on whether the modulation mode is set to the multicarrier mode or the single carrier mode.
[0042]
Next, the operation of the wireless device configured as described above will be described.
The wireless device of the third embodiment basically performs wireless communication using the OFDM modulation method. In such a state, the modulation mode switching unit 34 sets the multicarrier mode as the modulation mode.
[0043]
In the multicarrier mode, the signal switch 31 inputs digital data to the S / P converter 1. The S / P converter 1 rearranges the digital data into parallel data having the same width as the window width of the IFFT 4 and outputs the parallel data. In addition, the signal switching unit 32 inputs the output of the P / S converter 5 to the D / A converter 6. The frequency converter 33 converts the frequency of the output of the D / A converter 6 to the carrier frequency band for OFDM. Thus, in the multicarrier mode, OFDM modulation is performed by the S / P converter 1, IFFT 4, P / S converter 5, D / A converter 6 and frequency converter 33 according to a known procedure. The signal output from the frequency converter 33 is amplified by the transmission PA 8 and then wirelessly transmitted from the antenna 9.
[0044]
At this time, the signal input to the transmission PA 8 is a multicarrier signal having a spectrum as shown in FIG. 2 in the frequency domain. For this reason, the difference between the average power and the peak power is large. Therefore, in the multicarrier mode, the transmission PA 8 operates at an operating point that is in the low efficiency class. Thereby, it is possible to amplify a multicarrier signal as shown in FIG. 2 with high quality.
[0045]
The modulation mode switching unit 34 monitors the progress of the protocol based on the information output from the protocol control unit 11, and sets the single carrier mode at the timing of transmitting the kind of data having a low required transmission rate. To do.
[0046]
In the single carrier mode, the signal switchers 31 and 32 input digital data directly to the D / A converter 6. The frequency converter 33 frequency-converts the output of the D / A converter 6 to a carrier frequency band for single carrier. Thus, in the single carrier mode, the digital data is converted to analog without being subjected to inverse FFT, and then converted to a carrier frequency band for single carrier. Therefore, the frequency converter 33 outputs a signal having data on only one carrier for a single carrier. The output signal of the frequency converter 7 is amplified by the transmission PA 8 and then wirelessly transmitted from the antenna 9.
[0047]
At this time, the signal input to the transmission PA 8 is a single carrier signal having a spectrum as shown in FIG. 7 in the frequency domain. For this reason, the difference between the average power and the peak power is not so large, and the transmission PA 8 can amplify the transmission PA 8 without much deterioration in quality even when operating in the high efficiency class. Therefore, in the single carrier mode, the transmission PA 8 operates at an operating point that is a high efficiency class.
[0048]
As described above, according to the radio apparatus of the third embodiment, the transmission PA 8 is temporarily operated in the high efficiency class as in the first embodiment, thereby reducing the power consumption. Furthermore, the radio apparatus according to the third embodiment generates a single carrier signal without using a plurality of subcarriers used for OFDM modulation. Therefore, as shown in FIG. 7, the frequency band BW1 of the single carrier signal can be made larger than the frequency band BW2 assigned to one subcarrier, and the transmission rate is equal to or higher than the symbol rate that can be transmitted by one subcarrier. Can be secured.
[0049]
(Fourth embodiment)
FIG. 8 is a block diagram illustrating a configuration of a wireless device according to the fourth embodiment. The same parts as those in FIGS. 1, 4 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
The wireless apparatus of the fourth embodiment includes an S / P converter 1, an IFFT 4, a P / S converter 5, a D / A converter 6, a transmission PA 8, an antenna 9, a protocol control unit 11, a TPC receiver 21, and a signal. Switching units 31 and 32, a frequency converter 33 and a modulation mode switching unit 41 are included.
[0050]
That is, the wireless device of the fourth embodiment includes a modulation mode switching unit 41 instead of the modulation mode switching unit 34 in the wireless device of the third embodiment, and newly includes a TPC receiver 21.
[0051]
The modulation mode switching unit 41 obtains information on the progress of the protocol from the protocol control unit 11, obtains instruction information in the TPC signal from the TPC receiver 21, and sets the modulation mode based on these information to the multicarrier. Set to mode or single carrier mode. The modulation mode switching unit 41 switches the operations of the transmission PA 8, the signal switchers 31 and 32, and the frequency converter 33 depending on whether the modulation mode is set to the multicarrier mode or the single carrier mode.
[0052]
Next, the operation of the wireless device configured as described above will be described.
The modulation mode switching unit 41 switches the modulation mode according to the type of transmission data in the same manner as the modulation mode switching unit 34 in the third embodiment, but transmission power equal to or higher than the threshold is required by the TPC signal. If it is determined, the modulation mode is set to the single carrier mode regardless of the type of transmission data. Each operation state in the single carrier mode and the multicarrier mode is the same as that in the third embodiment.
[0053]
Thus, in a situation where it is necessary to perform transmission with a transmission power equal to or higher than the threshold value, a single carrier signal with a large power having a spectrum as shown in FIG. 9 in the frequency domain is obtained. For this reason, even if the transmission PA 8 is operating in the high efficiency class, it is possible to amplify the transmission PA 8 without much deterioration in quality.
[0054]
As described above, the radio apparatus according to the fourth embodiment basically realizes data transmission at a high rate using OFDM modulation. However, if the data to be transmitted has a low required transmission rate or needs to be transmitted with a transmission power equal to or higher than a threshold value, a single carrier signal is transmitted and the transmission PA 8 is operated in a high efficiency class. This makes it possible to reduce power consumption compared to the case where the transmission PA 8 is always operated in the low efficiency class. Furthermore, the radio apparatus according to the third embodiment generates a single carrier signal using one of a plurality of subcarriers used for OFDM modulation. For this reason, most of the circuits for OFDM modulation can be used for the generation of a single carrier signal, and the increase in circuit scale compared to a radio apparatus that always performs OFDM modulation can be suppressed small.
[0055]
In addition, when it is necessary to perform transmission with transmission power equal to or higher than the threshold value, the communication quality between the wireless device and the base station is deteriorated. In such a situation, the portable wireless device according to the fourth embodiment operates the transmission PA 8 in a high-efficiency class, so that transmission can be performed with sufficiently large transmission power, and information can be transmitted reliably. .
[0056]
In each of the embodiments described above, the type of data to be transmitted may be classified without depending on the protocol. For example, classification may be performed using an identifier or the like given to data input to the S / P converter 1. Alternatively, the type of data to which the multicarrier mode and the single carrier mode are respectively applied is defined by the data rate, and the data is classified based on the data rate measured for the data input to the S / P converter 1. You can also.
[0057]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0058]
【The invention's effect】
According to the present invention, the single carrier signal is temporarily transmitted according to the data to be transmitted, and the amplifying means is operated in the high efficiency class. A wireless device that can be reduced can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a wireless device according to a first embodiment.
FIG. 2 is a diagram showing a spectrum in a frequency domain of a signal input to the transmission PA 8 in FIG. 1 in a multicarrier mode.
FIG. 3 is a diagram showing a spectrum in a frequency domain of a signal input to the transmission PA 8 in FIG. 1 in a single carrier mode.
FIG. 4 is a block diagram showing a configuration of a wireless device according to a second embodiment.
5 is a diagram showing a spectrum in a frequency domain of a signal input to the transmission PA 8 in FIG. 4 in a single carrier mode.
FIG. 6 is a block diagram showing a configuration of a wireless device according to a third embodiment.
7 is a diagram showing a spectrum in a frequency domain of a signal input to the transmission PA 8 in FIG. 6 in a single carrier mode.
FIG. 8 is a block diagram showing a configuration of a wireless device according to a fourth embodiment.
9 is a diagram showing a spectrum in a frequency domain of a signal input to the transmission PA 8 in FIG. 8 in a single carrier mode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Serial / parallel (S / P) converter, 2-1 to 2-n ... Selector, 3-1 to 3-n ... Null value generator, 4 ... Inverse fast Fourier transformer (IFFT), 5 ... Parallel / Serial (P / S) converter, 6 ... digital / analog (D / A) converter, 7,33 ... frequency converter, 8 ... transmission power amplifier (transmission PA), 9 ... antenna, 10, 22, 34 , 41 ... modulation mode switching unit, 11 ... protocol control unit, 21 ... TPC receiver, 31, 32 ... signal switching unit.

Claims (6)

A setting means for selectively setting an OFDM ( Orthogonal Frequency Division Multiplex ) modulation mode and a single carrier modulation mode;
Modulation means said the OFD M Configuration modulation mode transmit data to OFDM modulation, said in setting the single-carrier modulation mode for single carrier modulation of the transmission data,
The output signal of the modulating means is amplified by setting sometimes power efficiency is relatively low first working point of the OFDM modulation mode, setting times power efficiency of the single career modulation mode is relatively high second Means for amplifying at the operating point;
Means for receiving a transmission power control signal designating transmission power ,
Further, the setting means is (1) when the transmission power specified by the transmission power control signal is less than a threshold and the transmission data is of the first type, and (2) the transmission power. When the transmission power specified by the control signal is less than the threshold and the transmission data is of the second type, the single carrier modulation mode is selected. (3) The transmission power specified by the transmission power control signal is equal to or greater than the threshold. If so, the single carrier modulation mode is set respectively .   The radio apparatus according to claim 1, wherein the modulation unit uses a band of one subcarrier in the OFDM modulation mode in the single carrier modulation mode. The modulating means includes
When the OFDM modulation mode is set, the transmission data is parallelized and output to a plurality of signal lines, and when the single carrier modulation mode is set, the transmission data is serially output to one of the plurality of signal lines and the other Means for nulling the signal line;
Means for performing inverse fast Fourier transform on data transmitted through the plurality of signal lines;
Means for serializing the inverse fast Fourier transformed data in the time domain;
Analogizing means for analogizing the serialized data;
The radio apparatus according to claim 2, further comprising means for converting the output signal of the analogization means to a carrier frequency band. The radio apparatus according to claim 1, wherein the modulation means uses a band wider than a band of one subcarrier in the OFDM modulation mode when the single carrier modulation mode is set . The modulating means includes
Means for parallelizing the transmission data and outputting it to a plurality of signal lines;
Means for performing inverse fast Fourier transform on data transmitted through the plurality of signal lines;
Means for serializing the inverse fast Fourier transformed data in the time domain;
And analog means for analog the data is the serialized during setting of the OFDM modulation mode, also when setting the single carrier modulation mode transmission data of the second type, respectively,
5. The radio apparatus according to claim 4 , further comprising means for frequency-converting the output signal of the analog means to a carrier frequency band. Wherein the second type, the wireless device according to any one of claims 1 to 5, characterized in that it comprises control information of the communication protocol.

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