JP2013131997A - Radio terminal and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio terminal and radio communication system which can provide excellent services, in accordance with the type of an application to be executed.SOLUTION: An application execution part 150 executes an application. A communication quality measurement part 151 measures communication quality in a downlink signal. An MCS level setting part 152 sets an MCS level of a downlink signal in accordance with the application to be executed and the measured communication quality in the downlink signal. The application to be executed includes a first type and a second type. The MCS level setting part 152, when the application to be executed is the second type, sets so that the MCS level set corresponding to substantially the same communication quality can be lower than that when the application to be executed is the first type. An MCS level notification part 154 notifies a radio base station of the MCS level of the set downlink signal.

Description

  The present invention relates to a wireless terminal and a wireless communication system.

  Conventionally, a wireless communication system that selects an MCS level based on communication quality is known.

  For example, in Patent Literature 1 (International Publication No. 2008/108227 pamphlet), a base station device that communicates with a user device using an uplink shared channel calculates a path loss between the user device and the base station device. And MCS selection means for selecting the MCS level of the shared channel based on the path loss.

International Publication No. 2008/108227 Pamphlet

  When the MCS level is high, the transmission data rate is high, but the frequency of communication errors increases. However, in the conventional wireless communication system, the MCS level is selected regardless of the type of application to be executed. .

  However, the degree of harmfulness of the service provided when a communication error occurs differs depending on the application.

  For example, when a web page is displayed by a web application, the page is required to be displayed quickly. If a communication error occurs during Web page display, a delay in page display may occur due to reacquisition of missing data. However, data can be reacquired in the Web application. For this reason, even if communication errors increase by increasing the MCS level, there are few adverse effects on the service. Conversely, in a Web application, even if a communication error occurs, missing data can be reacquired, so when the communication quality is good, if the MCS level is not increased, the transmission rate will be slowed and the service will be adversely affected. There is.

  On the other hand, in voice communication, it is required that voice is not interrupted during communication. If a communication error occurs during voice communication, the voice may be interrupted for a certain period of time. Therefore, if communication errors increase by raising the MCS level, there is a harmful effect on the service.

  Therefore, an object of the present invention is to provide a wireless terminal and a wireless communication system capable of providing a good service according to the type of application to be executed.

  The wireless terminal according to the present invention includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, an MCS of a downlink signal according to the application to be executed and the communication quality of the measured downlink signal. A setting unit for setting a level, and a notification unit for notifying the radio base station of the MCS level of the set downlink signal, and an application to be executed includes a first type and a second type, and the setting unit includes: When the application to be executed is the second type, the MCS level set corresponding to substantially the same communication quality is set to be lower than when the application to be executed is the first type.

  The wireless terminal of the present invention includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, a correction unit that corrects communication quality of a downlink signal based on the application to be executed, and a correction A notification unit that notifies the radio base station of the communication quality of the downlink signal that has been performed, the application to be executed includes a first type and a second type, and the correction unit has a second type when the application to be executed is the second type The correction is performed so that the corrected communication quality is lower than the measured communication quality that is substantially the same as when the application to be executed is the first type.

  The wireless terminal of the present invention includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, a correction unit that corrects communication quality of a downlink signal based on the application to be executed, and a correction An application that includes a setting unit that sets the MCS level of the downlink signal according to the communication quality of the downlink signal, and a notification unit that notifies the radio base station of the set MCS level of the downlink signal. Includes a first type and a second type, and when the application to be executed is the second type, the correction unit is configured to measure the communication quality substantially the same as when the application to be executed is the first type. Then, the communication quality after correction is corrected to a lower value.

  The wireless terminal according to the present invention includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and the latest n communication quality samples of the downlink signal based on the application to be executed. An averaging unit that calculates a moving average, a setting unit that sets an MCS level of a downlink signal according to a value of the moving average, and a notification unit that notifies the radio base station of the set MCS level of the downlink signal The application to be executed includes the first type and the second type, the value of n when the application to be executed is the first type is N1, the application to be executed is the second type, and the MCS level is lowered. N2 <N1 <N3 where n2 is N2 and n3 is N3 when raising the MCS level.

  The wireless terminal of the present invention includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and communication of a downlink signal according to the application to be executed and the communication quality of the measured downlink signal. A setting unit configured to set a level, and a notification unit configured to notify the radio base station of a communication level of the set downlink signal, and an application to be executed includes a first type and a second type, and the setting unit includes: When the application to be executed is the second type, the communication level set corresponding to substantially the same communication quality is set to be lower than when the application to be executed is the first type.

  Preferably, the first type of application is a web application, and the second type of application is an application related to audio and / or video.

  The present invention is a wireless communication system including a wireless terminal and a wireless base station, wherein the wireless terminal includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and an application that is executed. A radio base station comprising: a setting unit configured to set the MCS level of the downlink signal according to the measured communication quality of the downlink signal; and a notification unit configured to notify the radio base station of the set MCS level of the downlink signal. A level acquisition unit that receives notification of the MCS level of the downlink signal from the wireless terminal, an encoding unit that encodes the downlink signal based on the acquired MCS level, and a downlink based on the acquired MCS level And an application to be executed includes a first type and a second type, and includes a setting unit. , An application to be executed is the second type of time, application to be executed than when the first type, MCS level set corresponding to substantially the same communication quality is set to be lower.

  The present invention is a wireless communication system including a wireless terminal and a wireless base station, and the wireless terminal includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and an application that is executed. And a notifying unit for notifying the radio base station of the corrected communication quality of the downlink signal, and the radio base station receives the downlink signal from the radio terminal. A level acquisition unit that receives notification of communication quality, a setting unit that sets the MCS level of the downlink signal according to the communication quality of the notified downlink signal, and a downlink signal based on the set MCS level And an encoding unit for modulating the downlink signal based on the set MCS level. The application includes a first type and a second type, and the correction unit has a measured communication quality that is substantially the same when the application to be executed is the second type than when the application to be executed is the first type. On the other hand, the corrected communication quality is corrected to a lower value.

  The present invention is a wireless communication system including a wireless terminal and a wireless base station, and the wireless terminal includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and an application that is executed. A correction unit for correcting the communication quality of the downlink signal, a setting unit for setting the MCS level of the downlink signal according to the communication quality of the corrected downlink signal, and the MCS of the set downlink signal. A notification unit that notifies the radio base station of the level, and the radio base station encodes the downlink signal based on the acquired MCS level and a level acquisition unit that receives a notification of the MCS level of the downlink signal from the radio terminal. And a coding unit that modulates the downlink signal based on the acquired MCS level. The application includes a first type and a second type, and the correction unit has a measured communication quality that is substantially the same when the application to be executed is the second type than when the application to be executed is the first type. Is corrected so that the communication quality after correction becomes a lower value.

  The present invention is a wireless communication system including a wireless terminal and a wireless base station, and the wireless terminal includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and an application that is executed. And an averaging unit for calculating the moving average of the latest n communication quality samples of the downlink signal, and a setting unit for setting the MCS level of the downlink signal according to the value of the moving average. A notification unit that notifies the radio base station of the MCS level of the downlink signal, the radio base station receiving a notification of the MCS level of the downlink signal from the radio terminal, and based on the acquired MCS level An encoder that encodes the downlink signal, and a modulator that modulates the downlink signal based on the acquired MCS level. The application to be executed includes the first type and the second type. When the application to be executed is the first type, the value of n is N1, the application to be executed is the second type, and the MCS level is lowered. N2 <N1 <N3, where N is N2 and n is 3 when raising the MCS level.

  The present invention is a wireless communication system including a wireless terminal and a wireless base station, wherein the wireless terminal includes an application execution unit that executes an application, a measurement unit that measures communication quality of a downlink signal, and an application that is executed. A radio base station comprising: a setting unit configured to set a communication level of the downlink signal according to the measured communication quality of the downlink signal; and a notification unit configured to notify the radio base station of the set communication level of the downlink signal. A level acquisition unit that receives a notification of a communication level of a downlink signal from a wireless terminal, an encoding unit that encodes a downlink signal based on the acquired communication level, and a downlink based on the acquired communication level Based on the modulation unit that modulates the signal and the acquired communication level, the downlink signal is spatially multiplexed or space-time encoded. The application to be executed includes the first type and the second type, and the setting unit corresponds to substantially the same communication quality when the application to be executed is the second type than when the application to be executed is the first type. Thus, the MCS level set is set to be low.

  Preferably, the first type of application is a web application, and the second type of application is an application related to audio and / or video.

  According to the present invention, it is possible to provide a good service according to the type of application to be executed.

It is a figure showing the structure of the radio | wireless communications system of 1st Embodiment. It is a figure showing the structure of the radio | wireless terminal of 1st Embodiment. It is a figure for demonstrating the MCS level of a downlink signal. It is a figure showing the example of the 1st table of 1st Embodiment. It is a figure showing the example of the 2nd table of 1st Embodiment. It is a figure showing the structure of the wireless base station of 1st Embodiment. It is a figure showing the structure of the radio | wireless terminal of 2nd Embodiment. It is a figure showing the structure of the wireless base station of 2nd Embodiment. It is a figure showing the structure of the radio | wireless terminal of 3rd Embodiment. It is a figure showing the structure of the wireless base station of 3rd Embodiment. (A) is a figure for demonstrating the example of the change of CINR at the time of 1st type application execution. (B) is a figure for demonstrating the example of the change of the MCS level at the time of 1st type application execution. (A) is a figure for demonstrating the example of the change of CINR at the time of 2nd type application execution. (B) is a figure for demonstrating the example of the change of the MCS level at the time of execution of a 2nd type application. It is a figure showing the structure of the radio | wireless terminal of 4th Embodiment. It is a figure for demonstrating the communication level of a downlink signal. It is a figure showing the example of the 1st table of 4th Embodiment. It is a figure showing the example of the 2nd table of 4th Embodiment. It is a figure showing the structure of the wireless base station of 4th Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment.

  Referring to FIG. 1, the radio communication system includes a radio base station 2 and m radio terminals 3-1 to 3-m. The radio base station 2 can communicate with a plurality of m radio terminals 3-1 to 3-m simultaneously.

  Hereinafter, when any one of the wireless terminals 3-1 to 3-m is represented, it is referred to as a wireless terminal 3.

FIG. 2 is a diagram illustrating the configuration of the wireless terminal according to the first embodiment.
Referring to FIG. 2, this wireless terminal 102 includes a first antenna 110, a second antenna 111, a transmission unit 113, a reception unit 112, a MAC (Media Access Control) layer processing unit 114, an application, The execution unit 150 includes a first combiner / distributor 182 and a second combiner / distributor 183.

  The first combiner / distributor 182 is formed of, for example, a circulator, and outputs a signal from the transmission unit 113 to the first antenna 110 and outputs a signal from the first antenna 110 to the reception unit 112.

  The second combiner / distributor 183 is configured by, for example, a circulator, and outputs a signal from the transmission unit 113 to the second antenna 111 and outputs a signal from the second antenna 111 to the reception unit 112.

  The transmission unit 113 includes a multi-antenna transmission signal processing unit 124, a subcarrier arrangement unit 123, an IFFT unit (Inverse First Fourier Transform) 122, a CP (Cyclic Prefix) addition unit 121, an RF (Radio Frequency) unit 120, Is provided.

  The subcarrier arrangement unit 123 arranges subcarriers based on, for example, PUSC (Partial Usage of Subchannels).

  The multi-antenna transmission signal processing unit 124 performs adaptive array transmission processing on the uplink signal output from the subcarrier arrangement unit 123.

  The IFFT unit 122 converts a plurality of subcarrier signals (frequency domain signals) output from the multi-antenna transmission signal processing unit 124 into time domain signals (OFDMA (Orthogonal Frequency Division Multiple Access) symbols) by IFFT.

  CP adding section 121 adds the same signal as the tail part of the OFDMA symbol to the beginning of the OFDMA symbol as a CP.

  The RF unit 120 includes an up-converter that up-converts to a radio frequency band, a power amplification circuit that amplifies the up-converted signal, and passes only a signal component in a desired band of the amplified signal to pass through the first antenna 110 and the first antenna A band-pass filter that outputs to the second antenna 111.

  The reception unit 112 includes an RF unit 115, a CP removal unit 116, an FFT unit 117, a subcarrier arrangement unit 118, and a multi-antenna reception signal processing unit 181.

  The RF unit 115 includes a band-pass filter that passes only a signal component in a desired band among signals output from the first antenna 110 and the second antenna 111, a low-noise amplifier circuit that amplifies the RF signal, and the RF signal that is down Includes down coater to convert.

CP removing section 116 removes CP from the signal output from RF section 115.
The FFT unit 117 converts the time domain signal output from the CP removal unit 116 into a frequency domain signal by FFT and demodulates the signal into a plurality of subcarriers.

  The subcarrier arrangement unit 118 extracts each subcarrier output from the FFT unit 117 based on, for example, PUSC.

  Multi-antenna reception signal processing section 181 performs space-time decoding on a signal (a space-time encoded signal described later) output from subcarrier arrangement section 18.

  The MAC layer processing unit 114 includes a user data transmission management unit 134, an encoding unit 133, a modulation unit 132, a demodulation unit 125, a decoding unit 126, a user data reception management unit 127, and a control unit 135. .

The user data transmission management unit 134 manages user data to be transmitted to the radio base station 2.
The encoding unit 133 encodes an uplink signal to the radio base station 2.

The modulation unit 132 modulates the encoded uplink signal.
The demodulator 125 demodulates the downlink signal from the radio base station 2.

The decoding unit 126 decodes the demodulated downlink signal.
The user data reception management unit 27 manages user data received from the radio base station 2.

  The control unit 135 includes a communication quality measurement unit 151, an MCS (Modulation and Coding Scheme) level setting unit 152, a table storage unit 153, and an MCS level notification unit 154.

  The communication quality measurement unit 151 measures the carrier power to interference noise power ratio (CINR) of the downlink signal as the communication quality.

The table storage unit 153 stores the first table and the second table.
The first table is a table used when the first type of application is being executed. The first table defines the correspondence between the CINR of the downlink signal and the MCS level of the downlink signal. The second table is a table used when the second type of application is being executed. The second table defines the correspondence between the CINR of the downlink signal and the MCS level of the downlink signal.

  Here, the first type of application includes, for example, a web application for displaying a web page, and the second type of application communicates in real time related to voice and / or video such as an IP phone and a video phone. Includes applications to do.

FIG. 3 is a diagram for explaining the MCS level of the downlink signal.
As shown in FIG. 3, the MCS level has eight levels “1” to “8”. For each MCS level, a modulation scheme and a coding rate are determined. For example, the MCS level “1” indicates that the modulation scheme is “QPSK” and the coding rate is “½”. The higher the MCS level, the higher the transmission data rate. In the present specification, when the value of the MCS level is increased, when the value of the MCS level is increased, it is described that “the MCS level is increased (up)”, and when the value of the MCS level is decreased, “ It is described that the MCS level has decreased (down).

  FIG. 4 is a diagram illustrating an example of the first table. FIG. 5 is a diagram illustrating an example of the second table.

  The second table is a table that is one level lower than the first table. That is, when the measured CINR is greater than or equal to a3 and less than a4, the MCS level is set to “4” when the first table is used, whereas the MCS level is “3” when the second table is used. "Is set.

  The MCS level setting unit 152 is set so that when the application to be executed is the second type, the MCS level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. To do.

  Specifically, when the application to be executed is the first type, the MCS level setting unit 152 selects the first table and, according to the first table, the downlink signal corresponding to the measured CINR of the downlink signal. Set the MCS level. For example, when the measured CINR is a3 or more and less than a4, the MCS level setting unit 152 sets the MCS level to “4”.

  In addition, when the application to be executed is the second type, the MCS level setting unit 152 selects the second table and sets the MCS of the downlink signal corresponding to the measured CINR of the downlink signal according to the second table. Set. For example, when the measured CINR is greater than or equal to a3 and less than a4, the MCS level setting unit 152 sets the MCS level to “3”.

  The MCS level notification unit 154 outputs a signal that notifies the MCS level of the set downlink signal.

  The application execution unit 150 executes the first type application or the second type application.

FIG. 6 is a diagram illustrating the configuration of the radio base station according to the first embodiment.
Referring to FIG. 6, this radio base station 2 includes a first antenna 10, a second antenna 11, a transmission unit 13, a reception unit 12, a MAC layer processing unit 14, a first combination / A distributor 82 and a second coupler / distributor 83 are provided.

  The first combiner / distributor 82 is composed of, for example, a circulator, and outputs a signal from the transmission unit 13 to the first antenna 10 and outputs a signal from the first antenna 10 to the reception unit 12.

  Second combiner / distributor 83 is formed of, for example, a circulator, and outputs a signal from transmission unit 13 to second antenna 11 and outputs a signal from second antenna 11 to reception unit 12.

  The transmission unit 13 includes a multi-antenna transmission signal processing unit 24, a subcarrier arrangement unit 23, an IFFT unit (Inverse First Fourier Transform) 22, a CP (Cyclic Prefix) addition unit 21, an RF (Radio Frequency) unit 20, Is provided.

  The subcarrier arrangement unit 23 arranges subcarriers based on, for example, PUSC (Partial Usage of Subchannels).

  The multi-antenna transmission signal processing unit 24 corresponds to the MATRIX-A MIMO system defined by the WiMAX forum, and performs space-time coding (for example, Alamouch coding) on one data stream.

  The IFFT unit 22 converts a plurality of subcarrier signals (frequency domain signals) output from the multi-antenna transmission signal processing unit 24 into time domain signals (OFDMA (Orthogonal Frequency Division Multiple Access) symbols) by IFFT.

  The CP adding unit 21 adds the same signal as the tail part of the OFDMA symbol to the beginning of the OFDMA symbol as a CP.

  The RF unit 20 includes an up-converter that up-converts to a radio frequency band, a power amplification circuit that amplifies the up-converted signal, and passes only the signal component in the desired band of the amplified signal to pass through the first antenna 10 and the first antenna 10. A band-pass filter that outputs to the second antenna 11.

  The reception unit 12 includes an RF unit 15, a CP removal unit 16, an FFT unit 17, a subcarrier arrangement unit 18, and a multi-antenna reception signal processing unit 81.

  The RF unit 15 includes a band-pass filter that allows only a signal component in a desired band among signals output from the first antenna 10 and the second antenna 11 to pass, a low-noise amplifier circuit that amplifies the RF signal, and the RF signal Includes down coater to convert.

The CP removal unit 16 removes the CP from the signal output from the RF unit 15.
The FFT unit 17 converts the time domain signal output from the CP removal unit 16 into a frequency domain signal by FFT and demodulates the signal into a plurality of subcarriers.

  The subcarrier arrangement unit 18 extracts each subcarrier output from the FFT unit 17 based on PUSC, for example.

  The multi-antenna reception signal processing unit 81 performs adaptive array reception processing on the signal output from the subcarrier arrangement unit 18.

  The MAC layer processing unit 14 includes a user data transmission management unit 34, an encoding unit 33, a modulation unit 32, a demodulation unit 25, a decoding unit 26, a user data reception management unit 27, and a control unit 35. .

The user data transmission management unit 34 manages user data transmitted to the wireless terminal 3.
The encoding unit 33 encodes the downlink signal according to the MCS encoding rate instructed from the MCS switching unit 38.

  The modulation unit 32 modulates the encoded downlink signal according to the MCS modulation method instructed from the MCS switching unit 38.

The demodulator 25 demodulates the uplink signal from the wireless terminal 3.
The decoding unit 26 decodes the demodulated uplink signal.

The user data reception management unit 27 manages user data received from the wireless terminal 3.
The control unit 35 includes an MCS level acquisition unit 36 and an MCS switching unit 38.

  The MCS level acquisition unit 36 acquires a signal for notifying the MCS level transmitted from the wireless terminal 3.

  The MCS switching unit 38 switches the MCS of the downlink signal according to the notified MCS level.

  As described above, according to the wireless communication system of the present embodiment, a good service can be provided by changing the MCS level corresponding to the communication quality according to the type of application to be executed.

[Modification of First Embodiment]
In the first embodiment, the radio terminal sets the MCS level of the downlink signal based on the measured CINR and the type of application to be executed, and notifies the radio base station of the set MCS level of the downlink signal. . Then, the radio base station switches the MCS of the downlink signal according to the notified MCS level.

  On the other hand, in this modification, the notification unit of the wireless terminal notifies the measured CINR to the wireless base station. The acquisition unit of the radio base station acquires the notified CINR, and the setting unit sets the MCS level of the downlink signal based on the acquired CINR and the type of application to be executed. The switching unit of the radio base station switches the MCS of the downlink signal according to the set MCS level.

[Second Embodiment]
FIG. 7 is a diagram illustrating a configuration of a wireless terminal according to the second embodiment.

  The wireless terminal 202 in FIG. 7 is different from the wireless terminal 102 in the first embodiment in FIG. The control unit 235 includes a communication quality measurement unit 151, a communication quality correction unit 199, and a communication quality notification unit 155.

The communication quality measurement unit 151 measures the CINR of the downlink signal.
When the application to be executed is the second type, the communication quality correction unit 199 has a lower value of the communication quality after correction with respect to substantially the same measured communication quality than when the application to be executed is the first type. Correct so that As a result, when the second type application is executed, the MCS level set on the radio base station side can be made lower than when the first type application is executed.

  Specifically, when the application to be executed is the second type, the communication quality correction unit 199 subtracts the offset value α [dB] from the measured CINR value of the downlink signal to obtain the CINR of the downlink signal. to correct.

  The communication quality notification unit 155 outputs a signal that notifies the CINR of the corrected downlink signal.

FIG. 8 is a diagram illustrating the configuration of the radio base station according to the second embodiment.
The wireless base station 302 of FIG. 8 is different from the wireless base station 2 of the first embodiment of FIG.

  The control unit 335 includes a communication quality acquisition unit 159, an MCS level setting unit 192, a table storage unit 193, and an MCS switching unit 38.

  The communication quality acquisition unit 159 acquires a signal that notifies the CINR of the downlink signal transmitted from the wireless terminal 3.

The table storage unit 193 stores an application common table.
The application common table is a table that is used regardless of the type of application being executed. The application common table defines the correspondence between the CINR of the downlink signal and the MCS level of the downlink signal. As the application common table, for example, the first table described in the first embodiment may be used.

  The MCS level setting unit 192 sets the MCS level of the downlink signal corresponding to the notified CINR of the downlink signal according to the application common table.

  The MCS switching unit 38 switches the downlink signal MIMO communication method and the MCS according to the set MCS level.

  As described above, according to the wireless communication system of the present embodiment, it is possible to provide a good service by correcting the communication quality according to the type of application to be executed.

[Modification of Second Embodiment]
In the second embodiment, the radio terminal corrects the CINR of the downlink signal based on the type of application to be executed, and notifies the radio base station of the CINR of the downlink signal. Then, the radio base station sets the MCS level of the downlink signal based on the notified CINR of the downlink signal, and switches the MCS of the downlink signal according to the set MCS level.

  On the other hand, in this modification, the correction unit of the wireless terminal corrects the CINR of the downlink signal based on the type of application to be executed, and the setting unit performs the downlink based on the CINR of the downlink signal. The MCS level of the signal is set, and the notification unit notifies the radio base station of the set MCS level. Then, the acquisition unit of the radio base station acquires the notified MCS level, and the switching unit of the radio base station switches the MCS of the downlink signal according to the acquired MCS level.

[Third Embodiment]
FIG. 9 is a diagram illustrating the configuration of a wireless terminal according to the third embodiment.

  The wireless terminal 402 in FIG. 9 is different from the wireless terminal 102 in the first embodiment in FIG.

  The control unit 435 includes a communication quality measurement unit 151, a communication quality averaging unit 455, and a communication quality notification unit 456.

  The communication quality measurement unit 151 measures the carrier power to interference noise power ratio (CINR) of the downlink signal as the communication quality.

  When the application to be executed is the first type, the communication quality averaging unit 455 calculates the moving average of the latest N1 measured CINRs.

  When the application to be executed is the second type, the communication quality averaging unit 455 calculates the latest N2 measured CINR moving averages and the latest N3 measured CINR moving averages. However, N2 <N1 <N3. For example, N1 = 100, N2 = 10, and N3 = 200.

  When the application to be executed is the first type, the communication quality notification unit 456 outputs a signal that notifies the moving average value of the latest N1 measured CINRs. When the application to be executed is the second type, the communication quality notification unit 456 outputs a signal for notifying the latest N2 measured CINR moving average value and the latest N3 measured CINR moving average value. .

FIG. 10 is a diagram illustrating a configuration of a radio base station according to the third embodiment.
The wireless base station 502 in FIG. 10 is different from the wireless base station 2 in the first embodiment in FIG.

  The control unit 535 includes a communication quality acquisition unit 559, an MCS level setting unit 552, a table storage unit 193, and an MCS switching unit 38.

  The communication quality acquisition unit 559 acquires a signal that notifies the CINR of the downlink signal transmitted from the wireless terminal 3. When the application executed on the wireless terminal 3 is the first type, the communication quality acquisition unit 559 acquires a signal for notifying the latest N1 measured CINR moving average values, and the application executed on the wireless terminal 3 is the first application. In the case of two types, a signal for notifying the latest N2 measured CINR moving average values and the latest N3 measured CINR moving average values is acquired.

The table storage unit 193 stores an application common table.
The application common table is a table that is used regardless of the type of application being executed. This table defines the correspondence between the CINR of the downlink signal and the MCS level of the downlink signal. As the application common table, for example, the first table described in the first embodiment may be used.

  When the application being executed is the first type, the MCS level setting unit 552 sets the MCS level of the downlink signal corresponding to the latest N1 measured moving average value of the CINR reported according to the application common table. To do.

  When the application being executed is the second type, the MCS level setting unit 552 sets the MCS level of the downlink signal corresponding to the moving average value of the latest N2 CINRs when lowering the MCS level according to the application common table. Identify.

  When the application being executed is the second type, the MCS level setting unit 552 sets the MCS level of the downlink signal corresponding to the moving average value of the latest N3 CINRs to increase the MCS level according to the application common table. Identify.

  The MCS switching unit 38 switches between the MIMO communication system and MCS (modulation system and coding rate) of the downlink signal according to the set MCS level.

A change in the MCS level due to N2 <N1 <N3 as described above will be described.
FIG. 11A is a diagram for explaining an example of a change in CINR when the first type of application is executed. FIG. 11B is a diagram for explaining an example of a change in the MCS level when the first type of application is executed.

  As shown in (1) of FIG. 11B, the MCS level down in response to the deterioration of CINR.

  FIG. 12A is a diagram for explaining an example of CINR change during execution of the second type of application. FIG. 12B is a diagram for explaining an example of a change in the MCS level when the second type application is executed.

  As shown in (2) and (3) of FIG. 12B, when the second type application is executed, the level of MCS is lowered in response to CINR degradation more sensitively than when the first type application is executed. On the other hand, when the CINR is improved, when the second type application is executed, the MCS level is raised in response to a more careful response than when the first type application is executed.

  As described above, according to the wireless communication system of the present embodiment, it is possible to provide a good service by changing the period during which the communication quality is moving averaged according to the type of application to be executed.

[Modification of Third Embodiment]
In the third embodiment, the wireless terminal calculates the moving average value of the CINR of the downlink signal based on the type of application to be executed, and notifies the wireless base station of the moving average value of the CINR of the downlink signal. . Then, the radio base station sets the MCS level of the downlink signal based on the notified CINR moving average value of the downlink signal, and switches the MCS of the downlink signal according to the set MCS level.

  In this modification, as in the third embodiment, the communication quality averaging unit of the wireless terminal performs the latest N1 measurements when the application to be executed is the first type. The CINR moving average is calculated. When the application to be executed is the second type, the latest N2 measured CINR moving average and the latest N3 measured CINR moving average are calculated. However, N2 <N1 <N3.

  When the application being executed by the MCS level setting unit of the wireless terminal is the first type, the MCS level of the downlink signal corresponding to the latest N1 measured moving average value of CINR notified according to the application common table Set. When the application being executed is the second type, the MCS level setting unit of the wireless terminal uses the MCS of the downlink signal corresponding to the moving average value of the latest N2 CINRs to lower the MCS level according to the application common table. Identify the level. When the application being executed is the second type, the MCS level setting unit of the wireless terminal increases the MCS level according to the application common table, and the MCS of the downlink signal corresponding to the moving average value of the latest N3 CINRs Identify the level.

The notification unit notifies the radio base station of the set MCS level.
The acquisition unit of the radio base station acquires the notified MCS level, and the switching unit of the radio base station switches the MCS of the downlink signal according to the acquired MCS level.

[Fourth Embodiment]
In the fourth embodiment, according to the CINR of the downlink signal, in addition to the MCS of the downlink signal, the MIMO scheme of the downlink signal is also switched according to the type of application being executed. The switching conditions are different from those of the MCS and MIMO schemes.

FIG. 13 is a diagram illustrating a configuration of a wireless terminal according to the fourth embodiment.
The wireless terminal in FIG. 13 is different from the wireless terminal in the first embodiment in FIG.

  The multi-antenna reception signal processing unit 782 performs space-time decoding or space-demultiplexing on a signal (a space-time encoded signal or a space-multiplexed signal described later) output from the subcarrier arrangement unit 18.

  The control unit 735 includes a communication quality measurement unit 151, a communication level setting unit 152, a table storage unit 753, and a communication level notification unit 754.

  The communication quality measurement unit 151 measures the carrier power to interference noise power ratio (CINR) of the downlink signal as the communication quality.

The table storage unit 753 stores the first table and the second table.
The first table is a table used when the first type of application is being executed. The first table defines the correspondence between the CINR of the downlink signal and the communication level of the downlink signal.

  The second table is a table used when the second type of application is being executed. The second table defines the correspondence between the CINR of the downlink signal and the communication level of the downlink signal.

FIG. 14 is a diagram for explaining the communication level of the downlink signal.
As shown in FIG. 14, the communication level has eight levels “1” to “12”. For each communication level, a MIMO scheme, a modulation scheme, and a coding rate are determined. For example, the communication level “1” indicates that the MIMO scheme is MATRIX-A, the modulation scheme is “QPSK”, and the coding rate is “1/2”. The higher the communication level, the higher the transmission data rate. In this specification, it is described that “the communication level has increased (up)” when the communication level value increases, and “the communication level has decreased (down)” when the communication level value decreases. Describe.

  FIG. 15 is a diagram illustrating an example of the first table. FIG. 16 is a diagram illustrating an example of the second table.

  The second table is a table that is one level lower than the first table. That is, when the measured CINR is not less than b3 and less than b4, the communication level is set to “4” when the first table is used, whereas the communication level is “3” when the second table is used. "Is set.

  The communication level setting unit 752 is set so that when the application to be executed is the second type, the communication level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. To do.

  When the application to be executed is the first type, the communication level setting unit 752 selects the first table, and sets the MCS level of the downlink signal corresponding to the measured CINR of the downlink signal according to the first table. . For example, when the measured CINR is greater than or equal to b3 and less than b4, the communication level setting unit 752 sets the communication level to “4”.

  In addition, when the application to be executed is the second type, the communication level setting unit 752 selects the second table, and sets the MCS of the downlink signal corresponding to the measured CINR of the downlink signal according to the second table. Set. For example, when the measured CINR is greater than or equal to b3 and less than b4, the communication level setting unit 752 sets the communication level to “3”.

  The communication level notification unit 754 outputs a signal that notifies the communication level of the set downlink signal.

FIG. 17 is a diagram illustrating a configuration of a radio base station according to the fourth embodiment.
The radio base station 602 in FIG. 17 is different from the radio base station 2 in the first embodiment in FIG. 6 in a multi-antenna transmission signal processing unit 624 and a control unit 635.

  When the set MIMO scheme is MATRIX-A, multi-antenna transmission signal processing section 624 performs space-time coding (for example, Aramuch coding) on one data stream, and when the set MIMO scheme is MATRIX-B In addition, a plurality of data streams are spatially multiplexed.

The control unit 635 includes a communication level acquisition unit 636 and a switching unit 638.
The communication level acquisition unit 636 acquires a signal notifying the communication level transmitted from the wireless terminal 3.

  The switching unit 638 switches the downlink signal MIMO communication method and the MCS according to the notified communication level.

  As described above, according to the wireless communication system of the present embodiment, a good service can be provided by changing the communication level corresponding to the communication quality according to the type of application to be executed.

[Modification of Fourth Embodiment]
In the fourth embodiment, the wireless terminal sets the communication level of the downlink signal based on the measured CINR and the type of application to be executed, and notifies the wireless base station of the set communication level of the downlink signal. . Then, the radio base station switches the MCS and MIMO scheme of the downlink signal according to the notified communication level.

  On the other hand, in this modification, the notification unit of the wireless terminal notifies the measured CINR to the wireless base station. The acquisition unit of the radio base station acquires the notified CINR, and the setting unit sets the communication level of the downlink signal based on the acquired CINR and the type of application to be executed. The switching unit of the radio base station switches the MCS and MIMO scheme of the downlink signal according to the set communication level.

(Modification)
(1) Communication quality In this embodiment, CINR is used as communication quality, but PER (Packet Error Rate) may be used. Also, depending on the communication method, RSRQ (Reference Signal Received Quality) may be used for communication quality measurement, and the MCS level itself may be reported as a communication quality report.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Wireless communication system, 2,302,502,602 Wireless base station, 3,3-1 to 3-m, 102,202,402,702 Wireless terminal 10,11,110,111 Antenna, 12,112 Transmitter 13, 113 receiving unit, 14, 114 MAC layer processing unit, 15, 20, 115, 120 RF unit, 16, 116 CP removing unit, 17, 117 FFT unit, 18, 23, 118, 123 subcarrier arrangement unit, 21, 121 CP adding unit, 22, 122 IFFT unit, 24, 124, 624 Multi-antenna transmission signal processing unit, 25, 125 demodulation unit, 26, 126 decoding unit, 27, 127 User data reception management unit, 32, 132 modulation Part, 33, 133 encoding part, 34, 134 User data transmission management part, 35, 135, 235, 335, 435, 6 35,735 Control unit, 36 MCS level acquisition unit, 38 MCS level switching unit, 150 Application execution unit, 151 Communication quality measurement unit, 152,192,552 MCS level setting unit, 153,193,753 Table storage unit, 154 MCS Level notification unit, 155,456 Communication quality notification unit, 159,559 Communication quality acquisition unit, 199 Communication quality correction unit, 455 Communication quality averaging unit, 81,181,782 Multi-antenna reception signal processing unit, 82,182 First Coupling / distributor, 83, 183 second coupling / distributor, 636 communication level acquisition unit, 638 switching unit, 752 communication level setting unit, 754 communication level notification unit.

Claims (12)

An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A setting unit configured to set the MCS level of the downlink signal according to the application to be executed and the communication quality of the measured downlink signal;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The application to be executed includes a first type and a second type,
The setting unit is set so that when the application to be executed is the second type, the MCS level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. Wireless terminal. An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A correction unit for correcting communication quality of the downlink signal based on the application to be executed;
A notification unit for notifying a radio base station of the communication quality of the corrected downlink signal,
The application to be executed includes a first type and a second type,
When the application to be executed is the second type, the correction unit has a lower communication quality after correction with respect to substantially the same measured communication quality than when the application to be executed is the first type. A wireless terminal that corrects to be An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A correction unit for correcting communication quality of the downlink signal based on the application to be executed;
A setting unit configured to set the MCS level of the downlink signal according to the communication quality of the corrected downlink signal;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The application to be executed includes a first type and a second type,
When the application to be executed is the second type, the correction unit has a lower communication quality after correction with respect to substantially the same measured communication quality than when the application to be executed is the first type. A wireless terminal that corrects to be An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
An averaging unit that calculates a moving average of the latest n communication quality samples of the downlink signal based on the application to be executed;
A setting unit for setting the MCS level of the downlink signal according to the value of the moving average;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The application to be executed includes a first type and a second type,
The value of n when the application to be executed is the first type is N1, the value of n when the application to be executed is the second type and the MCS level is lowered is N2, and the value of n is when the MCS level is raised. A wireless terminal in which N2 <N1 <N3 when the value is N3. An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A setting unit for setting a communication level of a downlink signal according to the application to be executed and the communication quality of the measured downlink signal,
A notification unit for notifying a radio base station of the communication level of the set downlink signal,
The application to be executed includes a first type and a second type,
The setting unit is set so that when the application to be executed is the second type, the communication level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. Wireless terminal. The first type of application is a web application,
The wireless terminal according to any one of claims 1 to 5, wherein the second type of application is an application related to audio and / or video. A wireless communication system including a wireless terminal and a wireless base station,
The wireless terminal is
An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A setting unit configured to set the MCS level of the downlink signal according to the application to be executed and the communication quality of the measured downlink signal;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The radio base station is
A level acquisition unit that receives a notification of an MCS level of a downlink signal from the wireless terminal;
An encoding unit for encoding a downlink signal based on the acquired MCS level;
A modulation unit that modulates a downlink signal based on the acquired MCS level;
The application to be executed includes a first type and a second type,
The setting unit is set so that when the application to be executed is the second type, the MCS level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. A wireless communication system. A wireless communication system including a wireless terminal and a wireless base station,
The wireless terminal is
An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A correction unit for correcting communication quality of the downlink signal based on the application to be executed;
A notification unit for notifying a radio base station of the communication quality of the corrected downlink signal,
The radio base station is
A level acquisition unit for receiving notification of communication quality of a downlink signal from the wireless terminal;
A setting unit configured to set the MCS level of the downlink signal according to the communication quality of the notified downlink signal;
An encoding unit for encoding a downlink signal based on the set MCS level;
A modulation unit that modulates a downlink signal based on the set MCS level;
The application to be executed includes a first type and a second type,
When the application to be executed is the second type, the correction unit has a lower communication quality after correction with respect to substantially the same measured communication quality than when the application to be executed is the first type. A wireless communication system that corrects so that A wireless communication system including a wireless terminal and a wireless base station,
The wireless terminal is
An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A correction unit for correcting communication quality of the downlink signal based on the application to be executed;
A setting unit configured to set the MCS level of the downlink signal according to the communication quality of the corrected downlink signal;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The radio base station is
A level acquisition unit that receives a notification of an MCS level of a downlink signal from the wireless terminal;
An encoding unit for encoding a downlink signal based on the acquired MCS level;
A modulation unit that modulates a downlink signal based on the acquired MCS level;
The application to be executed includes a first type and a second type,
When the application to be executed is the second type, the correction unit has a lower communication quality after correction with respect to substantially the same measured communication quality than when the application to be executed is the first type. A wireless communication system that corrects so that A wireless communication system including a wireless terminal and a wireless base station,
The wireless terminal is
An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
An averaging unit that calculates a moving average of the latest n communication quality samples of the downlink signal based on the application to be executed;
A setting unit for setting the MCS level of the downlink signal according to the value of the moving average;
A notification unit for notifying the radio base station of the MCS level of the set downlink signal,
The radio base station is
A level acquisition unit that receives a notification of an MCS level of a downlink signal from the wireless terminal;
An encoding unit for encoding a downlink signal based on the acquired MCS level;
A modulation unit that modulates a downlink signal based on the acquired MCS level;
The application to be executed includes a first type and a second type,
The value of n when the application to be executed is the first type is N1, the value of n when the application to be executed is the second type and the MCS level is lowered is N2, and the value of n is when the MCS level is raised. A wireless communication system in which N2 <N1 <N3 when the value is N3. A wireless communication system including a wireless terminal and a wireless base station,
The wireless terminal is
An application execution unit for executing the application;
A measurement unit for measuring communication quality of the downlink signal;
A setting unit for setting a communication level of a downlink signal according to the application to be executed and the communication quality of the measured downlink signal,
A notification unit for notifying a radio base station of the communication level of the set downlink signal,
The radio base station is
A level acquisition unit that receives a communication level of a downlink signal from the wireless terminal;
An encoding unit for encoding a downlink signal based on the acquired communication level;
A modulation unit that modulates a downlink signal based on the acquired communication level;
Based on the acquired communication level, the downlink signal is spatially multiplexed or space-time encoded,
The application to be executed includes a first type and a second type,
The setting unit is set so that when the application to be executed is the second type, the MCS level set corresponding to substantially the same communication quality is lower than when the application to be executed is the first type. A wireless communication system. The first type of application is a web application,
The wireless communication system according to any one of claims 7 to 11, wherein the second type of application is an application related to voice and / or video.

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