WO2007135868A1 - 通信システム、通信装置、及び通信レート変更方法 - Google Patents
通信システム、通信装置、及び通信レート変更方法 Download PDFInfo
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- WO2007135868A1 WO2007135868A1 PCT/JP2007/059704 JP2007059704W WO2007135868A1 WO 2007135868 A1 WO2007135868 A1 WO 2007135868A1 JP 2007059704 W JP2007059704 W JP 2007059704W WO 2007135868 A1 WO2007135868 A1 WO 2007135868A1
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- communication rate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
- H04W28/18—Negotiating wireless communication parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/262—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account adaptive modulation and coding [AMC] scheme
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/267—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account the information rate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
- H04W28/18—Negotiating wireless communication parameters
- H04W28/22—Negotiating communication rate
Definitions
- the present invention relates to a communication system, a communication apparatus, and a communication rate changing method, and more particularly to a technique for preventing a demodulation from being disturbed after the communication rate is increased.
- signal distortion significantly affects demodulation in high-rate communication. This distortion increases as the transmission power increases. Therefore, some transmission apparatuses reduce the transmission power in response to an increase in communication rate in order to reduce signal distortion. For this reason, the received power may decrease after the communication rate is changed.
- Patent Document 1 describes a technique that allows uplink transmission power control to be performed on a terminal in accordance with a transmission environment when a plurality of terminals are spatially multiplexed with a base station. Yes.
- Patent Document 1 Japanese Patent Laid-Open No. 2003-244070
- one of the problems of the present invention is to provide a communication system, a communication device, and a communication rate changing method capable of preventing the demodulation from being disturbed after the communication rate is increased. .
- a communication system for solving the above-described problem includes a transmission device and a reception device, and the transmission device modulates transmission data using one of a plurality of modulation schemes.
- the modulation means for generating a transmission signal
- the transmission means for transmitting the transmission signal generated by the modulation means
- the transmission means Transmission power lowering means for lowering the transmission power at the time of transmitting the transmission signal by a predetermined change amount
- the reception device receives the transmission signal transmitted by the transmission means,
- a reception power information acquisition unit that acquires reception power information indicating reception power when the transmission signal is received by the reception unit; and in a predetermined case, the modulation unit
- the communication rate changing means for changing the communication rate by changing the modulation method used more, the received power information acquired by the received power information acquiring means, and the amount of change in the transmission power by the transmission power lowering means And received power when the transmission signal is received by the receiving
- received signal quality information acquiring means for acquiring received signal quality information indicating received signal quality when the transmission signal is received by the receiving means
- a communication rate A storage for storing necessary reception signal quality information indicating necessary reception signal quality that is necessary for the reception device to demodulate a transmission signal received by the reception means in association with communication rate information indicating
- the received signal quality indicated by the received signal quality information acquired by the received signal quality information acquiring means in association with the communication rate information indicating the communication rate after the change by the communication rate changing means.
- Determination means for performing threshold determination as a threshold value, wherein the communication rate changing means changes a communication rate according to a determination result of the determination means, and the communication rate increase limiting means If the power does not exceed the reception power required for the receiving apparatus to demodulate the transmission signal received by the receiving means, the threshold used in the threshold judgment by the judging means is the high received signal quality. Thus, the communication rate changing means restricts the communication rate from being increased, and the predicted received power is the reception power required for the receiving apparatus to demodulate the transmission signal received by the receiving means. If the value exceeds the threshold, the threshold used in the threshold determination by the determination means may be the required received signal quality.
- the communication rate is changed by determining a threshold value of received signal quality. Therefore
- the threshold used for the threshold determination is set to high received signal quality so that the communication rate does not increase until reception power corresponding to the high received signal quality is obtained.
- distortion of the transmission signal may increase as the transmission power increases, and the received signal quality may be saturated. In such a case, the correlation between the received signal quality and the received power is lost.
- the threshold used for threshold determination is high received signal quality
- the predicted received power exceeds the received power required for demodulation by the receiving apparatus, and the received signal Even if the quality exceeds the required received signal quality, the increase in the communication rate may be limited.
- the received signal quality indicated by the necessary received signal quality information is set as a threshold value. Therefore, the communication rate can be increased appropriately.
- the high received signal quality is determined based on a change amount of transmission power due to the transmission power lowering means and the required received signal quality. As well.
- the threshold used for threshold determination of the received signal quality is set as the high received signal quality. As a result, it is possible to prevent the communication rate from increasing until the necessary reception power is obtained after the communication rate is changed.
- a communication device acquires a reception unit that receives a transmission signal transmitted by a transmission device, and reception power information indicating reception power when the transmission signal is received by the reception unit.
- Receiving power information obtaining means for performing, in a predetermined case, a communication rate changing means for changing a communication rate by changing a modulation method used by the transmitting apparatus to modulate the transmission signal, and the received power information obtaining means.
- the communication rate predicted based on the received power information acquired by the communication rate change means and the amount of change in the transmission power of the transmission signal that the transmission apparatus lowers in response to an increase in the communication rate by the communication rate changing means
- the reception power when the receiving unit receives the transmission signal and the transmission signal received by the receiving unit by the receiving unit are restored.
- the communication rate changing method includes a modulation step of modulating transmission data by using any one of a plurality of modulation methods and generating a transmission signal in the transmission device;
- the transmission signal is increased.
- a transmission power lowering step for decreasing the transmission power when transmitting the transmission signal in a transmission step by a predetermined change amount; and a reception step for receiving the transmission signal transmitted by the transmission means in the receiving device.
- a reception power information acquisition step for acquiring reception power information indicating reception power when the transmission signal is received in the reception step, and in a predetermined case, the modulation step.
- the communication rate change step for changing the communication rate by changing the modulation method used in the transmission step, the reception power information acquired in the reception power information acquisition step, and the transmission power in the transmission power decrease step And the received power when receiving the transmission signal in the receiving step after the change in the communication rate in the communication rate changing step, which is predicted based on the amount of change in the communication rate, and the receiving device in the receiving step Depending on the received power required to demodulate the received transmission signal, the communication And a communication rate increase limiting step for limiting an increase in communication rate in the rate changing step.
- FIG. 1 is a diagram showing a system configuration of a mobile communication system according to an embodiment of the present invention.
- FIG. 2 is a diagram showing a system configuration of a base station apparatus that works according to an embodiment of the present invention.
- FIG. 3 is a diagram showing a system configuration of a mobile station apparatus that works according to an embodiment of the present invention.
- FIG. 4 is a diagram showing a threshold value storage table useful for the embodiment of the present invention.
- FIG. 5 is a diagram showing a transmission power decrease amount-received signal quality offset value correspondence table according to the embodiment of the present invention.
- FIG. 6 is a diagram showing a frame structure of a transmission signal according to an embodiment of the present invention.
- FIG. 7 is a diagram showing a processing flow of the mobile station apparatus according to the embodiment of the present invention.
- FIG. 8 is a diagram showing a processing flow of the mobile station apparatus which is useful for the embodiment of the present invention.
- FIG. 9 is a diagram showing a process flow of the mobile station apparatus according to the embodiment of the present invention.
- FIG. 10 is an explanatory diagram for explaining the function and effect of the embodiment of the present invention, in particular an explanatory diagram for explaining the relationship between received power and received signal quality.
- FIG. 11 is an explanatory diagram for explaining the operational effect of the embodiment of the present invention, and in particular, an explanatory diagram for explaining the relationship between the distance between the base station device and the mobile station device and the communication rate change. It is.
- FIG. 12 is an explanatory diagram for explaining the function and effect of the embodiment of the present invention, and more particularly an explanatory diagram for explaining a correlation between received signal quality and received power.
- FIG. 1 is a diagram showing a system configuration of a mobile communication system 1 that works according to the present embodiment.
- the mobile communication system 1 includes a base station device 10 and a mobile station device 20.
- Each of the base station device 10 and the mobile station device 20 is a computer including a CPU and a memory.
- the CPU is a processing unit for executing programs stored in memory. In addition to performing processing to control each unit of each device, each function described later is realized.
- the memory stores programs and data for carrying out this embodiment. It also works as a CPU work memory.
- Base station apparatus 10 and mobile station apparatus 20 perform wireless communication with each other while controlling the communication rate by adaptive modulation. This communication rate control is performed by determining the threshold value of the received signal quality.
- the mobile station apparatus 20 receives a radio signal wirelessly transmitted by the base station apparatus 10 and controls the communication rate of the radio signal transmitted by the base station apparatus 10 by threshold determination of the received signal quality. Will be explained.
- FIG. 2 is a diagram showing functional blocks of the base station device 10.
- the base station device 10 functionally includes a transmission data acquisition unit 11, a modulation scheme determination unit 12, a physical layer frame generation unit 13, an encoding Z modulation unit 14, an RF (Radio Frequency) / lF. (Inter-frequency) / BB (Base Band) unit 15, demodulation Z decoding unit 16, received data acquisition unit 17, request modulation method acquisition unit 18, transmission power control unit 19, and storage unit 40.
- RF Radio Frequency
- BB Base Band
- FIG. 3 is a diagram showing functional blocks of the mobile station device 20.
- the mobile station device 20 functionally includes an RFZIFZBB unit 21, a demodulation Z decoding unit 22, a communication rate change unit 23, a received data acquisition unit 24, a threshold calculation unit 25, a storage unit 26, and a communication rate.
- the ascending restriction unit 27, the transmission data acquisition unit 28, the modulation scheme determination unit 29, the physical layer frame generation unit 30, and the encoded Z modulation unit 31 are configured.
- the demodulation Z decoding unit 22 is further configured to include a received signal quality calculation unit 220 and a received power calculation unit 221 internally, and the communication rate change unit 23 further includes a FER (Frame Error Rate) calculation unit 230,
- the determination unit 231 is included.
- the transmission data acquisition unit 11 acquires transmission data to be transmitted to the mobile station device 20.
- the modulation scheme determining unit 12 determines a modulation scheme to be used for modulation of transmission data acquired by the transmission data acquiring unit 11 in accordance with an instruction from a request modulation scheme acquiring unit 18 described later.
- the physical layer frame generation unit 13 adds a physical layer header to the transmission data acquired by the transmission data acquisition unit 11 and outputs it to the encoding Z modulation unit 14.
- Physical layer frame generation The unit 13 includes modulation scheme information indicating the modulation scheme determined by the modulation scheme determination unit 12 in the physical layer header thus added.
- the encoding Z modulation unit 14 encodes the transmission data after the addition of the physical layer header input from the physical layer frame generation unit 13 by a predetermined encoding method, and acquires the encoded data.
- the encoding Z modulation unit 14 supports a plurality of modulation schemes.
- the encoding Z modulation unit 14 modulates a portion including the modulation scheme information (predetermined modulation portion) of the encoded data by a predetermined modulation scheme and the other portion (adaptive modulation portion) as a modulation scheme determination unit. Modulate using the modulation method determined by 12.
- the encoding Z modulation unit 14 generates and acquires a transmission signal by such modulation.
- the RFZIFZBB unit 15 wirelessly transmits the transmission signal acquired by the encoding Z modulation unit 14 by the superheterodyne method.
- the transmission power control unit 19 controls transmission power when the RFZIFZBB unit 15 transmits a transmission signal.
- the transmission power control unit 19 determines the transmission power when the transmission signal is transmitted by the RFZIFZBB unit 15. Decrease by a predetermined descent amount (change amount).
- the storage unit 40 stores the transmission power decrease amount table!
- the transmission power decrease amount table is a table that stores the communication rate after change and the decrease amount in association with each other.
- the transmission power control unit 19 reads the amount of decrease stored in association with the communication rate after the change from the transmission power decrease amount table when the modulation scheme used by the code Z modulation unit 14 is changed. . Then, the RFZIFZBB unit 15 decreases the transmission power when transmitting the transmission signal by the read decrease amount.
- RFZIFZBB unit 21 receives a transmission signal wirelessly transmitted by base station apparatus 10 by super dyne method and outputs the signal to demodulation Z decoding unit 22.
- Demodulation Z decoding unit 22 demodulates a predetermined modulation portion of the transmission signal input from RFZIFZBB unit 21 using the predetermined modulation method.
- the demodulating Z decoding unit 22 acquires the data power obtained as a result of this demodulation, and the modulation scheme information, and converts the adaptive modulation portion of the transmission signal input from the RFZIFZBB unit 21 into the modulation scheme indicated by the acquired modulation scheme information. Demodulate more.
- Demodulation Z decoding unit 22 further encodes data obtained as a result of such demodulation.
- the data is decoded by the predetermined code method to obtain a physical layer header and transmission data.
- the reception data acquisition unit 24 acquires the transmission data acquired by the demodulation Z decoding unit 22 as reception data.
- Received signal quality calculation section 220 is the quality of the transmission signal input from RFZIFZBB section 21.
- Received signal quality information indicating (received signal quality) is calculated and output to determination section 231.
- Specific examples of received signal quality information include SNR and EVM.
- the FER calculation unit 230 calculates the FER (Frame Error Rate) of the received data, and this FER may be used as the received signal quality information.
- the reception power calculation unit 221 calculates reception power information indicating the amplitude (reception power) of the transmission signal input from the RFZIFZBB unit 21 and outputs the reception power information to the communication rate increase restriction unit 27.
- the communication rate changing unit 23 changes the communication rate by changing the modulation scheme used by the code Z modulation unit 14 in a predetermined case. The functions for this change will be described in detail below.
- the storage unit 26 stores a threshold value storage table shown in FIG. 4 and a transmission power decrease amount reception signal quality offset value correspondence table shown in FIG.
- the threshold storage table includes the communication rate, the required received power A1, the required received signal quality B1, the transmission power decrease amount X, the decrease amount reflecting required reception power A2, and the decrease amount.
- This is a table for storing the necessary reception signal quality B3 for reflection in association with it.
- Necessary received power A1 is information indicating received power required to demodulate a transmission signal when a transmission signal of a corresponding communication rate is received by the RFZIFZBB unit 21.
- the necessary reception signal quality B1 is information indicating the reception signal quality necessary for demodulating the transmission signal when the transmission signal of the corresponding communication rate is received by the RFZIFZBB unit 21.
- the transmission power decrease amount X is information indicating the decrease amount of the transmission power by the transmission power control unit 19 when the communication rate is changed to the corresponding communication rate. As long as the transmission power decrease amount X is the same for all mobile station apparatuses 20, it may be stored in advance in the threshold storage table as station data of the base station apparatus 10. On the other hand, when different for each mobile station apparatus 20, the mobile station apparatus 20 starts communication with the base station apparatus 10, It is preferable to transmit the stored contents of the transmission power decrease amount table to the base station apparatus 10. In this case, the base station device 10 stores a threshold value storage table for each mobile station device 20. Then, the base station device 10 writes the transmission power decrease amount X in the threshold storage table stored for the mobile station device 20 based on the transmission power decrease amount table received from the mobile station device 20.
- the reduction amount reflecting necessary received signal quality B3 is determined based on the transmission power decrease amount X and the necessary received signal quality B1.
- the transmission power decreases due to the control of the transmission power control unit 19. Therefore, in order to realize the necessary reception power after the change of the communication rate, the reception power before the change of the communication rate is reduced. It must be higher than the required received power after changing the communication rate by the amount X of the decrease in transmission power.
- this value is the received power A2 that reflects the decrease amount
- the base station apparatus 10 determines whether or not the communication rate can be changed by determining the threshold value of the received signal quality, so that the received power exceeds the required reception power A2 that reflects the decrease amount.
- the base station apparatus 10 assumes that there is a correlation between the received power and the received signal quality, and increases the required received signal quality after changing the communication rate by an amount corresponding to the transmission power decrease amount X.
- the received signal quality B3 that needs to be reflected is the threshold used in the above threshold determination.
- the threshold calculation unit 25 is based on the transmission power decrease amount X and the necessary received signal quality B1 stored in the threshold storage table, and the transmission power decrease amount received signal quality offset value correspondence table. Then, the received signal quality B3 required to reflect the descent amount is calculated. Details will be described below.
- the transmission power decrease amount reception signal quality offset value correspondence table is a table that stores the transmission power decrease amount X and the reception signal quality offset value B 2 in association with each other.
- Base station apparatus 10 stores a transmission power decrease amount-received signal quality offset value correspondence table as station data in advance.
- the threshold calculation unit 25 first acquires the transmission power decrease amount X stored in the threshold storage table for the decrease amount reflection necessary received signal quality B3 to be calculated. Then, the threshold value calculation unit 25 acquires the received signal quality offset value B2 stored in the transmission power decrease amount-received signal quality offset value correspondence table in association with the acquired decrease amount reflecting necessary received power A2.
- the determination unit 231 correlates the received signal quality indicated by the received signal quality information acquired by the received signal quality calculating unit 220 with the communication rate information indicating the changed communication rate. Threshold determination is performed using either the required received signal quality indicated by the required received signal quality B1 stored in the threshold value storage table or a higher received signal quality higher than the required received signal quality B1 as a threshold value. Note that it is preferable to use the received signal quality indicated by the descending amount reflecting required received signal quality B3 stored in the threshold value storage table as the high received signal quality.
- the communication rate changing unit 23 changes the communication rate according to the determination result of the determining unit 231.
- processing for increasing the communication rate (described later) is performed. That is, if the received signal quality indicated by the received signal quality information acquired by the received signal quality calculation unit 220 exceeds the threshold, processing for increasing the communication rate is performed. If the determination result of the determination unit 231 is negative, no special processing is performed. In a predetermined case, the communication rate changing unit 23 also performs processing for lowering the communication rate.
- the communication rate increase restriction unit 27 predicts the received power information acquired by the received power calculation unit 221 and the transmission power decrease amount X, and changes the communication rate by the communication rate change unit 23. Later, RFZIFZBB unit 21 receives the transmission power when receiving the transmission signal, and necessary Depending on the received power Al, the communication rate changing unit 23 limits the increase in the communication rate.
- the communication rate increase restriction unit 27 indicates that the reception power indicated by the reception power information acquired by the reception power calculation unit 221 is the threshold value storage table after the communication rate change unit 23 changes the communication rate. Reflecting the amount of decrease stored in association with the communication rate of the communication rate changing unit 23 by setting the threshold used in the threshold determination by the determination unit 231 as the high received signal quality when the required received power A2 is not exceeded. Restricts the increase in communication rate.
- the communication rate increase restriction unit 27 is used in threshold determination by the determination unit 231 when the reception power indicated by the reception power information acquired by the reception power calculation unit 222 exceeds the decrease amount reflection necessary reception power A2. Is the required received signal quality.
- the communication rate increase limiting unit 27 determines the threshold used in the threshold determination by the determination unit 231 when the predicted received power does not exceed the required received power A1 as the high received signal. By setting the quality, the communication rate changing unit 23 is restricted from increasing the communication rate. On the other hand, when the predicted received power exceeds the required received power A1, the communication rate increase limiting unit 27 sets the threshold value used in the threshold determination by the determining unit 231 as the required received signal quality.
- the transmission data acquisition unit 28, the modulation scheme determination unit 29, the physical layer frame generation unit 30, the encoding Z modulation unit 31, and the RFZIFZBB unit 21 include a transmission data acquisition unit 11, a modulation scheme determination unit 12, and a physical layer frame.
- a transmission signal is generated and wirelessly transmitted in the same manner as the generation unit 13, the encoded Z modulation unit 14, and the RFZIFZBB unit 15.
- the communication rate changing unit 23 includes information for causing the base station device 10 to increase the communication rate in the physical layer header added by the physical layer frame generating unit 30 at this time. Specifically, information indicating the modulation scheme for realizing the changed communication rate is included in the requested modulation scheme field of the physical layer header.
- FIG. 6 is a diagram illustrating a format example of a transmission signal including a required modulation scheme field.
- the transmission signal consists of a physical layer and an upper layer.
- the physical layer includes a header and a required modulation method field.
- the upper layer is composed of transmission data.
- CRC is a cyclic redundancy code and is used for error correction and FER calculation.
- the demodulation Z decoding unit 16 and the reception data acquisition unit 17 acquire reception data in the same manner as the demodulation Z decoding unit 22 and the reception data acquisition unit 24.
- the required modulation scheme acquisition unit 18 reads information included in the required modulation scheme field from the physical layer header acquired by the demodulation Z decoding unit 16 at this time. Then, the modulation method determination unit 12 is instructed to use the modulation method indicated by the read information as the modulation method used to modulate the transmission data acquired by the transmission data acquisition unit 11.
- FIG. 7 is a diagram showing a processing flow of pre-processing performed by the mobile station device 20 in order to perform communication rate change processing.
- the mobile station device 20 first acquires the transmission power decrease amount X for each communication rate (Sl).
- the mobile station device 20 writes the transmission power decrease amount X thus obtained in the threshold storage table.
- the mobile station apparatus 20 writes A2 and B3 calculated in this way into the threshold value storage table (S5).
- FIG. 8 is a diagram showing a processing flow of communication rate change processing performed by the mobile station device 20.
- the mobile station device 20 first acquires the received power of the received signal (S10), and acquires the received signal quality (S11). Then, the mobile station device 20 acquired in S10 It is determined whether or not the received power is greater than the received power A2 required for reflecting the amount of decrease stored in association with the communication rate one step higher than the current communication rate (S12).
- mobile station apparatus 20 determines whether or not the received signal quality acquired in S11 exceeds the necessary received signal quality B1. (S13). As a result, if it is shown that the rate is exceeded, the mobile station device 20 performs processing for changing the communication rate (S14).
- the mobile station device 20 If it is not indicated that the determination result power of S12 is exceeded, the mobile station device 20 has a power that the received signal quality acquired in S15 exceeds the reception signal quality B3 that needs to reflect the amount of decrease. It is determined whether or not (S15). As a result, if it is shown that the rate is exceeded, the mobile station device 20 performs processing for changing the communication rate (S16).
- FIG. 9 is a modification of the processing flow shown in FIGS. 7 and 8.
- the mobile station device 20 first acquires the amount of decrease in transmission power when the communication rate is increased by one step (S20). Also, the mobile station device 20 acquires the received power of the received signal (S21). Then, the predicted received power is calculated by subtracting the amount of decrease in the transmission power acquired in S20 from the received power acquired in S21 (S22).
- the mobile station apparatus 20 determines whether the predicted received power exceeds the received power (required received power) required when the communication rate after the communication rate change is increased by one level! Is determined (S23).
- the mobile station apparatus 20 receives the received signal required when the received signal quality of the received signal increases the communication rate by one step. It is determined whether or not the quality (required received signal quality) is exceeded (S24). As a result, if it is shown that the rate has been exceeded, the mobile station device 20 performs processing for changing the communication rate (S25).
- the mobile station apparatus 20 does not indicate that the reception signal quality required when the reception signal quality of the reception signal increases the communication rate by one step. It is determined whether or not the received signal quality (high received signal quality) is higher than (required received signal quality) (S26). As a result, if it is shown that the rate is exceeded, the mobile station device 20 performs processing for changing the communication rate (S27). [0070] As described above, according to the mobile communication system 1, the change in the communication rate can be limited when the predicted received power after the increase in the communication rate is lower than the required received power. After the communication rate is increased, demodulation can be prevented from being hindered.
- the communication rate does not increase until reception power corresponding to the high received signal quality is obtained. If the predicted received power exceeds the received power required for demodulation by the mobile station device 20, the required received signal quality is used as a threshold value, so the communication rate can be increased appropriately. Can be implemented.
- the threshold used for the threshold determination of the received signal quality is the fall amount reflecting received signal quality reflecting the transmission power fall amount, the necessary received power can be obtained after changing the communication rate. Until then, the communication rate does not increase.
- FIG. 10 is an explanatory diagram for explaining the relationship between received power and received signal quality.
- the vertical axis represents the received power before the communication rate rises
- the horizontal axis represents the received signal quality.
- FIG. 10 (1) shows a case where the threshold value of the received signal quality for determining whether or not the communication rate can be increased is the required received signal quality.
- the received power decreases by the amount of transmitted power decrease. Therefore, in order to obtain the required reception power after the communication rate has increased, the reception power before the communication rate has to increase must be at least “required reception power + transmission power decrease”.
- the base station If the received power before the communication rate increases is equal to or greater than the "required received power + transmitted power decrease amount", the base station also increases the communication rate after the received signal quality exceeds the required received signal quality. The station apparatus 10 and the mobile station apparatus 20 can continue communication without any problem (T1 region). On the other hand, if the received power before the communication rate rises below the “required received power + transmission power drop amount” V, then the communication rate is raised because the received signal quality exceeds the required received signal quality. The received power is lower than the required received power. For this reason, an error occurs (T2 area). Note that the mobile communication system 1 does not increase the communication rate when the received signal quality falls below the required received signal quality (area T3). FIG.
- FIG. 10 (2) shows a case where the threshold value of the received signal quality for determining whether or not the communication rate can be increased is the falling amount reflected received signal quality. In this case, changing the communication rate is restricted in the T2 area. As a result, no error occurs as in Figure 10 (1).
- FIG. 10 (1) and Fig. 10 (2) the case has been described where the received signal quality and the received power are correlated. In practice, however, the received signal quality may not increase as the received power increases.
- Figure 10 (3) is a diagram for explaining such a case. In the region of T4 in the figure, the received signal quality reaches the received signal quality reflecting the decrease amount, but the received power exceeds “required received power + transmit power decrease amount”. In such a case, according to the present embodiment, the communication rate can be increased. After increasing the communication rate in this way, the base station device 10 and the mobile station device 20 can continue communication without any problem. Although the relationship between the received signal quality and received power in the figure may fall within the area of T5 in the figure, the mobile communication system 1 does not increase the communication rate in such a case.
- RU the relationship between the received signal quality and received power in the figure may fall within the area of T5 in the figure, the mobile communication system 1 does not increase the communication rate in such a case.
- FIG. 11 is an explanatory diagram for explaining the relationship between the distance between the base station device 10 and the mobile station device 20 and the communication rate change. If there is no obstacle, the base station device 10 is transmitting a signal with a constant transmission power, and the received power when the mobile station device 20 receives the signal transmitted by the base station device 10 is It is proportional to the distance between device 10 and mobile station device 20.
- the mobile station device 20 exists in the region U1, and gradually approaches the base station device 10.
- the communication rate is R1.
- the received power of the mobile station device 20 becomes the required received power A1 at the communication rate R2 at the boundary between the area U1 and the area U2.
- the received signal quality corresponding to this received power is the required received signal quality B1 at the communication rate R2, and when the threshold is determined based on the required received signal quality, the communication rate is changed from R1 to R2 at this boundary.
- the transmission power of the base station apparatus 10 decreases by the transmission power decrease amount X. For this reason, the received power of the mobile station device 20 is A1-X, and the base station device 10 cannot receive normally.
- the communication rate is changed.
- the mobile station device 20 crosses the boundary between the areas U2 and U3, the communication rate is changed from R1 to R2.
- FIG. 12 is an explanatory diagram for explaining the correlation between received signal quality and received power.
- the horizontal axis represents the received signal quality
- the vertical axis represents the frequency of hardware appearance.
- the received signal quality is saturated depending on the hardware.
- Figure 12 shows the hardware distribution of saturated received signal quality.
- the center of the distribution lies between the required received signal quality and the required received signal quality that reflects the descent amount.
- the saturation received signal quality needs to exceed the received signal quality that reflects the amount of decrease.
- the required received signal quality is set as the threshold if it can be ensured that even the received power exceeds the required received power. In this way, the communication rate can be changed from R1 to R2 on many hardware.
- the present invention is not limited to the above embodiment.
- an example in which the present invention is applied to a mobile communication system has been described.
- the present invention can be applied to any communication system that employs adaptive modulation.
- the present invention is applied to the mobile communication system, the above embodiment has described the case where the mobile station device 20 is a receiving device, but the same applies to the case where the base station device 10 is a receiving device. It is possible to apply this invention to.
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/301,438 US8014811B2 (en) | 2006-05-19 | 2007-05-11 | Communication system, communication device and communication rate modification method |
CN2007800181791A CN101449611B (zh) | 2006-05-19 | 2007-05-11 | 通信系统、通信装置及通信速率变更方法 |
EP07743139A EP2023509A4 (en) | 2006-05-19 | 2007-05-11 | COMMUNICATION SYSTEM AND DEVICE, AND METHOD OF MODIFYING COMMUNICATION RATE |
US13/192,339 US8478326B2 (en) | 2006-05-19 | 2011-07-27 | Communication system, communication device and communication rate modification method |
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JP2006-140807 | 2006-05-19 | ||
JP2006140807A JP4805016B2 (ja) | 2006-05-19 | 2006-05-19 | 通信システム、通信装置、及び通信レート変更方法 |
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US12/301,438 A-371-Of-International US8014811B2 (en) | 2006-05-19 | 2007-05-11 | Communication system, communication device and communication rate modification method |
US13/192,339 Division US8478326B2 (en) | 2006-05-19 | 2011-07-27 | Communication system, communication device and communication rate modification method |
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US (2) | US8014811B2 (ja) |
EP (1) | EP2023509A4 (ja) |
JP (1) | JP4805016B2 (ja) |
CN (1) | CN101449611B (ja) |
WO (1) | WO2007135868A1 (ja) |
Families Citing this family (8)
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JP5188371B2 (ja) * | 2008-11-26 | 2013-04-24 | 京セラ株式会社 | 無線通信装置および無線通信方法 |
JP5660043B2 (ja) * | 2009-09-16 | 2015-01-28 | 日本電気株式会社 | 通信装置、通信制御方法、及びコンピュータ読み取り可能な記録媒体 |
WO2011118546A1 (ja) * | 2010-03-24 | 2011-09-29 | 日本電気株式会社 | 通信装置、通信システム、及び通信制御方法 |
GB2515042A (en) * | 2013-06-11 | 2014-12-17 | Broadcom Corp | Receiver configuration |
KR102233039B1 (ko) * | 2013-10-29 | 2021-03-30 | 삼성전자주식회사 | 코히런트 및 넌-코히런트 수신기들에 연속적인 전송을 위해 터너리 시퀀스들을 사용하는 방법 및 시스템 |
JP6578831B2 (ja) | 2015-09-08 | 2019-09-25 | ソニー株式会社 | 無線通信装置および無線通信方法 |
US10757655B1 (en) * | 2019-04-18 | 2020-08-25 | At&T Intellectual Property I, L.P. | Uplink interference avoidance under closed loop power control conditions |
US11039398B2 (en) | 2019-05-31 | 2021-06-15 | At&T Intellectual Property I, L.P. | Uplink interference avoidance under open loop power control conditions |
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- 2007-05-11 CN CN2007800181791A patent/CN101449611B/zh not_active Expired - Fee Related
- 2007-05-11 WO PCT/JP2007/059704 patent/WO2007135868A1/ja active Application Filing
- 2007-05-11 US US12/301,438 patent/US8014811B2/en not_active Expired - Fee Related
- 2007-05-11 EP EP07743139A patent/EP2023509A4/en not_active Withdrawn
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Also Published As
Publication number | Publication date |
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EP2023509A4 (en) | 2010-04-07 |
US20110281529A1 (en) | 2011-11-17 |
CN101449611A (zh) | 2009-06-03 |
US8014811B2 (en) | 2011-09-06 |
US20100003926A1 (en) | 2010-01-07 |
JP2007312245A (ja) | 2007-11-29 |
JP4805016B2 (ja) | 2011-11-02 |
CN101449611B (zh) | 2011-05-04 |
EP2023509A1 (en) | 2009-02-11 |
US8478326B2 (en) | 2013-07-02 |
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