JP2010219659A - Radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce loads of a radio communication device and a network by determining a modulation system corresponding to the throughput of an application. <P>SOLUTION: A cellular phone set 1 is the radio communication device for selecting one from a plurality of modulation systems of different data rates and receiving data from a base station, and includes an application part 40 for executing the application, a resource part 50 for notifying the free condition of resources used by the application part 40, and a protocol part 60 for selecting one from the plurality of modulation systems on the basis of the free condition of the resource notified by the resource part 50 and requesting data transmission by the selected modulation system to the base station. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus that performs data reception using an adaptive modulation method.

  Some wireless communication devices such as cellular phones and PHS (Personal Handyphone System) employ a plurality of modulation schemes with different data rates. These often employ adaptive modulation schemes that determine which modulation scheme to use at predetermined intervals in accordance with the radio conditions between the radio communication device and the base station. Usually, in the adaptive modulation scheme, the error tolerance becomes lower as the data rate is higher. Therefore, it is determined to use a modulation scheme having a higher data rate as the radio state is better.

  In addition, in this adaptive modulation system, a technique for further improving the stability of communication has been proposed. For example, Patent Document 1 discloses a method for determining a modulation method according to not only a wireless state but also a data amount to be transmitted.

JP 2008-11107 A

  However, when the reception data rate is high, depending on the processing capability of the application in the wireless communication device, processing of the received data may not catch up and may be busy. In this case, the network utilization efficiency decreases due to data packets and busy packets that cannot be received.

  An object of the present invention is to determine a modulation scheme according to the processing capability of an application and reduce the load on a wireless communication device and a network.

  A wireless communication apparatus according to the present invention is a wireless communication apparatus that receives data from a base station by selecting one of a plurality of modulation schemes having different data rates, the application unit executing an application, and the application unit A resource unit that notifies the availability of resources used by the resource unit, and one of the plurality of modulation schemes is selected based on the availability of resources notified by the resource unit, and data transmission is performed according to the selected modulation scheme And a protocol unit that requests the base station.

  Further, it is preferable that the protocol unit selects one of the plurality of modulation schemes so that the resource availability notified by the resource unit approaches a predetermined level.

  In addition, it is preferable that the resource unit notifies the protocol unit of a free time of the application unit as a free state of the resource.

  The plurality of modulation schemes are preferably two or more modulation schemes including a modulation scheme with high error tolerance but low data rate and a modulation scheme with high data rate but low error tolerance.

  The plurality of modulation schemes preferably include any one of BPSK, QPSK, 8PSK, 16QAM, 32QAM, and 64QAM.

  ADVANTAGE OF THE INVENTION According to this invention, a modulation system can be determined according to the processing capacity of an application, and the load of a radio | wireless communication apparatus and a network can be reduced.

1 is an external perspective view of a mobile phone according to an embodiment of the present invention. It is a block diagram which shows the function of the mobile telephone which concerns on embodiment of this invention. It is a figure which shows the measuring method of the idle time which concerns on embodiment of this invention. It is a figure which shows the modulation system table which concerns on embodiment of this invention. It is a flowchart which shows the process of the protocol part which concerns on embodiment of this invention. It is a sequence diagram which shows the process example in the case of reducing the multi-value number of the modulation system which concerns on embodiment of this invention. It is a sequence diagram which shows the process example in the case of raising the multi-value number of the modulation system which concerns on embodiment of this invention.

  Hereinafter, an example of a preferred embodiment of the present invention will be described. In the present embodiment, a mobile phone 1 will be described as an example of a wireless communication device. Note that the wireless communication device of the present invention is not limited to this. For example, in addition to PHS and PDA (Personal Digital Assistant), a navigation device having a communication function, a personal computer, and a communication module connected thereto. It can be applied to various wireless communication devices.

  FIG. 1 is an external perspective view of a mobile phone 1 (wireless communication apparatus) according to the present embodiment. FIG. 1 shows a so-called foldable mobile phone, but the mobile phone according to the present invention is not limited to this. For example, a sliding type in which one casing is slid in one direction from a state in which both casings are overlapped, or a rotary type in which one casing is rotated around an axis along the overlapping direction ( Turn type), or a type (straight type) in which the operation unit and the display unit are arranged in one housing and does not have a connecting unit.

  The mobile phone 1 includes an operation unit side body 2 and a display unit side body 3. The operation unit side body 2 includes an operation unit 11 and a microphone 12 into which a voice uttered by a user of the mobile phone 1 is input on the surface unit 10. The operation unit 11 includes a function setting operation button 13 for activating various functions such as various setting functions, a telephone book function, and a mail function, and an input operation button 14 for inputting numbers of telephone numbers, mail characters, and the like. , And a determination operation button 15 for performing determination and scrolling in various operations.

  The display unit side body 3 includes a display unit 21 for displaying various types of information on the surface unit 20 and a receiver 22 for outputting the voice of the other party of the call.

  Further, the upper end portion of the operation unit side body 2 and the lower end portion of the display unit side body 3 are connected via a hinge mechanism 4. In addition, the mobile phone 1 relatively rotates the operation unit side body 2 and the display unit side body 3 which are connected via the hinge mechanism 4, so that the operation unit side body 2 and the display unit side body 3 are rotated. The body 3 can be in an open state (open state), or the operation unit side body 2 and the display unit side body 3 can be folded (folded state).

  FIG. 2 is a block diagram showing functions of the mobile phone 1 according to the present embodiment. The mobile phone 1 includes an operation unit 11, a display unit 21, a control unit 30, a communication unit 31, an antenna 32, a voice control unit 33, and a memory unit 34.

  The control unit 30 controls the entire mobile phone 1, and performs predetermined control on the display unit 21, the communication unit 31, the voice control unit 33, and the like, for example. In addition, the control unit 30 receives input from the operation unit 11 or the like and executes various processes. Then, the control unit 30 controls the memory unit 34 to perform reading of various programs and data, and writing of data when executing processing.

  The communication unit 31 communicates with an external device (base station) in a predetermined use frequency band (for example, 2 GHz band, 800 MHz band, etc.). The communication unit 31 demodulates the signal received from the antenna 32, supplies the processed signal to the control unit 30, modulates the signal supplied from the control unit 30, and transmits from the antenna 32 to the external device. Send to.

  The sound control unit 33 performs predetermined sound processing on the signal supplied from the communication unit 31 under the control of the control unit 30, and outputs the processed signal to the receiver 22. The receiver 22 outputs the signal supplied from the audio control unit 33 to the outside. This signal may be output from a speaker (not shown) instead of or together with the receiver 22.

  In addition, the voice control unit 33 processes a signal input from the microphone 12 according to the control of the control unit 30 and outputs the processed signal to the communication unit 31. The communication unit 31 performs a predetermined process on the signal supplied from the audio control unit 33 and outputs the processed signal from the antenna 32.

  The memory unit 34 includes, for example, a working memory and is used for arithmetic processing by the control unit 30. In addition, various programs according to the present embodiment and a modulation scheme table described later are stored. The memory unit 34 may also serve as a removable external memory.

  In addition, the control unit 30 includes an application unit 40, a resource unit 50, and a protocol unit 60, and each bears various functions according to the present embodiment.

  The application unit 40 executes various programs stored in the memory unit 34. At this time, the application unit 40 sequentially provides the data received by the protocol unit 60 via the communication unit 31 to the application program.

  The resource unit 50 monitors, for example, the processing status of the application unit 40 as the availability of resources used by the control unit 30. Then, the resource unit 50 notifies the protocol unit 60 of the ratio of time (idle time) during which the application unit 40 is not processing periodically (for example, every second).

  FIG. 3 is a diagram illustrating a method for measuring idle time according to the present embodiment. The application unit 40 executes a plurality of tasks 1, 2 and 3 by time division. The resource unit 50 measures the time during which no task is being executed using a timer, and obtains it as idle time.

  The protocol unit 60 determines the radio quality with the base station, and acquires the modulation scheme used when receiving data from the base station. Specifically, for example, when the received electric field strength from the base station is measured as an index of wireless communication quality, and it is determined that the received electric field strength is strong and the error rate is low, the data rate is high (the number of multivalues is large). Adopt modulation method.

  Further, upon receiving a notification from the resource unit 50 regarding the idle time of the application unit 40, the protocol unit 60 adjusts and determines the modulation method. The protocol unit 60 requests the determined modulation scheme from the base station, thereby changing the modulation scheme of data transmitted from the base station. Note that the protocol unit 60 periodically requests a modulation scheme to the base station regardless of whether there is a notification from the resource unit 50 (for example, every 5 milliseconds).

  FIG. 4 is a diagram illustrating a modulation scheme table that defines modulation schemes that can be selected in wireless communication according to the present embodiment. In the present embodiment, BPSK, QPSK, 8PSK, 16QAM, 32QAM, and 64QAM are defined corresponding to the multi-value numbers 0 to 5, respectively. Note that the type of modulation scheme is not limited to this, and it may be two or more modulation schemes having different data rates.

  Here, the smaller the multi-value number, the lower the transmission data rate, but the higher the error tolerance. Conversely, the larger the multi-value number, the higher the transmission data rate but the lower the error tolerance. That is, when the radio wave condition is good and stable communication is possible, high-speed communication is possible by increasing the multi-value number. However, if the processing of the control unit 30 cannot catch up with the received data rate, the received data is discarded or a control frame for notifying the busy state is transmitted. Usage efficiency will decrease. Therefore, the protocol unit 60 performs the following control.

  FIG. 5 is a flowchart showing processing of the protocol unit 60 according to the present embodiment. In this processing, the protocol unit 60 adjusts the modulation method so that the idle time of processing of the application unit 40 is 50% to 75%.

  In step S1, the protocol unit 60 determines the radio quality with the base station, and acquires a modulation method having a high data rate within a range in which the communication error rate can be maintained below a certain level.

  In step S <b> 2, the protocol unit 60 determines whether there is a notification from the resource unit 50 regarding the ratio of the idle time of the application unit 40. If this determination is YES, since the availability of the application unit 40 periodically notified from the resource unit 50 is acquired, the process proceeds to step S3 to adjust the modulation method. On the other hand, if the determination is NO, the process proceeds to step S16.

  In step S3, the protocol unit 60 determines whether or not the percentage of free time acquired in step S2 is 25% or less. If this determination is YES, the process proceeds to step S4, and if the determination is NO, the process proceeds to step S5.

  In step S4, the protocol unit 60 sets the number of multivalues in the modulation scheme table (FIG. 4) to 2 in order to reduce the reception data rate because the idle time ratio of the application unit 40 is 25% or less and the load is very large. Step down (eg, 8PSK to BPSK).

  In step S5, the protocol unit 60 determines whether or not the percentage of free time acquired in step S2 is 50% or less. If this determination is YES, the process proceeds to step S6, and if the determination is NO, the process proceeds to step S7.

  In step S6, the protocol unit 60 has a load ratio of the application unit 40 that is larger than 25% but less than 50%, and the load is large. Decrease the number of values by one step (for example, 8PSK to QPSK).

  In step S7, the protocol unit 60 determines whether or not the percentage of free time acquired in step S2 is 75% or less. If this determination is YES, the process proceeds to step S8, and if the determination is NO, the process proceeds to step S9.

  In step S8, the protocol unit 60 does not change the modulation method in order to maintain the reception data rate because the ratio of the idle time of the application unit 40 is larger than 50% but moderate at 75% or less.

  In step S9, the protocol unit 60 determines whether or not the percentage of free time acquired in step S2 is 90% or less. If this determination is YES, the process proceeds to step S10, and if the determination is NO, the process proceeds to step S11.

  In step S10, the protocol unit 60 has a free time ratio of the application unit 40 that is larger than 75% but 90% or less, so that there is a margin, so that the reception data rate is increased. Increase the number of values by one level (eg, 8PSK to 16QAM).

  In step S11, the protocol unit 60 has a large free time ratio of the application unit 40 that is larger than 90%, so that the reception data rate is increased. Increase by two levels (eg, 8PSK to 32QAM).

  In step S12, the protocol unit 60 determines whether or not the multi-value number determined by the conditional branching in steps S3 to S11 is larger than the maximum value (corresponding to 64QAM) stored in the modulation scheme table. If this determination is YES, the process proceeds to step S13, and if the determination is NO, the process proceeds to step S14.

  In step S13, since the multilevel number has become an undefined value, the protocol unit 60 sets the multilevel number in the modulation scheme table as the maximum value and sets the modulation scheme to 64QAM.

  In step S14, the protocol unit 60 determines whether or not the multi-value number determined by the conditional branching in steps S3 to S11 is smaller than the minimum value (corresponding to BPSK) stored in the modulation scheme table. If this determination is YES, the process proceeds to step S15, and if the determination is NO, the process proceeds to step S16.

  In step S15, since the multi-value number has become an undefined value, the protocol unit 60 sets the multi-value number in the modulation method table to the minimum value and sets the modulation method to BPSK.

  In step S16, since the availability of the application unit 40 periodically notified from the resource unit 50 has not been acquired, the protocol unit 60 does not change the modulation scheme and determines the modulation scheme acquired in step S1. .

  FIG. 6 is a sequence diagram showing a processing example when the multi-level number of the modulation scheme according to this embodiment is lowered.

  The resource unit 50 periodically measures the idle time of the application unit 40 and notifies the protocol unit 60 of it. Further, the protocol unit 60 periodically determines the modulation method (Mod (r)) according to the idle time of the application unit 40, and transmits a request to the base station. The base station changes the modulation method (Mod (s)) of data to be transmitted to the mobile phone 1 to the requested method until the next request is received from the mobile phone 1, and continues the transmission process.

  Specifically, Mod (s) = 32QAM was requested to request Mod (r) = 32QAM, and reception was performed at a high data rate, but the load on the application unit 40 was increased by the resource unit 50. Is detected, and the data rate is gradually lowered to Mod (r) = 16QAM and Mod (r) = 8PSK. Along with this, the interval at which received data is provided to the application unit 40 increases, and the processing load on the application unit 40 is reduced.

  FIG. 7 is a sequence diagram illustrating a processing example when increasing the multi-level number of the modulation scheme according to the present embodiment.

  Similar to FIG. 6, the protocol unit 60 determines the modulation method (Mod (r)) according to the idle time of the application unit 40 periodically notified, and transmits a request to the base station. The base station changes the modulation method (Mod (s)) of data to be transmitted to the mobile phone 1 to the requested method until the next request is received from the mobile phone 1, and continues the transmission process.

  More specifically, Mod (s) = 8PSK is requested and Mod (s) = 8PSK, and reception is performed at a low data rate. However, the load on the application unit 40 is reduced by the resource unit 50 and there is a margin. If it is detected, the data rate is gradually increased to Mod (r) = 16QAM and Mod (r) = 32QAM. Along with this, the interval at which received data is provided to the application unit 40 is narrowed, and it can be expected that the throughput of data processing by the application unit 40 is improved.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 Mobile phone (wireless communication device)
DESCRIPTION OF SYMBOLS 11 Operation part 21 Display part 30 Control part 31 Communication part 32 Antenna 33 Voice control part 34 Memory part 40 Application part 50 Resource part 60 Protocol part

Claims (5)

A wireless communication device that selects one of a plurality of modulation schemes having different data rates and receives data from a base station,
An application part that executes the application;
A resource part for notifying the availability of resources used by the application part;
And a protocol unit that selects one of the plurality of modulation schemes based on the resource availability notified by the resource unit and requests the base station to perform data transmission according to the selected modulation scheme. Communication device.   The wireless communication apparatus according to claim 1, wherein the protocol unit selects one of the plurality of modulation schemes so that a resource availability state notified by the resource unit approaches a predetermined level.   The wireless communication apparatus according to claim 1, wherein the resource unit notifies the protocol unit of a free time of the application unit as a free state of the resource.   The plurality of modulation schemes are two or more modulation schemes including a modulation scheme having a high error tolerance but a low data rate and a modulation scheme having a high data rate but a low error tolerance. The wireless communication device according to any one of the above.   The wireless communication apparatus according to claim 4, wherein the plurality of modulation schemes include any one of BPSK, QPSK, 8PSK, 16QAM, 32QAM, and 64QAM.

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