JP4750073B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus capable of controlling transmission power at the time of transmission in wireless communication, and in particular, according to a communication speed at the time of data communication and an estimated transmission time required to complete transmission of transmission target data. The present invention relates to a wireless communication apparatus that performs detailed power control.

  Conventionally, there are various types of portable wireless communication devices. Portable wireless communication devices limit the amount of power consumed by the built-in power supply, so the transmission power is controlled according to the wireless communication status so that a long usage time can be secured. There are models that try to suppress this.

For example, Patent Literature 1 below discloses a radio paging transmitter that switches transmission output in accordance with a change in data transmission rate (bps). Patent Document 2 below discloses a wireless LAN device that controls transmission power based on a total of three items: reception power level, packet error rate, and communication speed (bps). Further, Patent Document 3 below discloses a card-type wireless LAN that adjusts transmission power in accordance with the degree of decrease in the remaining power amount of a built-in power supply.
JP 2000-22627 A JP 2005-117303 A Japanese Patent Laid-Open No. 2003-347943

  In the radio paging transmitter according to Patent Document 1 described above, transmission power is controlled in consideration of only the data transmission rate, so the radio paging transmitter automatically increases the transmission power because the data transmission rate is high. In this case, if the user tries to transmit a large amount of data, the state in which the power consumption is increased continues for a long time. Therefore, when the amount of transmission data is large, there is a problem of excessive power consumption. In the wireless LAN device according to Patent Document 2, transmission power is controlled without considering the amount of transmission data, so that the same problem may occur.

  Furthermore, since the card type wireless LAN according to Patent Document 3 simply adjusts transmission power in consideration of the degree of decrease in the remaining amount of power, the communication speed and the amount of data to be transmitted when performing wireless communication. The transmission power cannot be controlled according to Such problems occur uniformly regardless of various communication standards (wireless communication standards such as IEEE802.11 wireless LAN, Wireless USB, UWB (Ultra Wide Band), Wireless1394, etc.) of wireless communication devices. It is a problem to do.

  The present invention has been made in view of such a problem, and by controlling transmission power based on a data communication speed and a data amount of data to be transmitted, the communication speed is high and the data amount is small. The present invention relates to a wireless communication apparatus that can transmit data and that can suppress excessive power consumption if the amount of data is large.

  In order to solve the above problems, a wireless communication apparatus according to the present invention compares a communication speed of received data with a reference speed in a wireless communication apparatus that controls transmission power based on a communication speed of received data related to wireless communication. When the communication speed of the received data exceeds the reference speed as a result of the comparison by the speed comparison means and the speed comparison means, a time calculation means for calculating an estimated transmission time required for completion of transmission of the transmission target data based on the communication speed; Transmission power that is higher than the reference transmission power when the estimated transmission time is less than the reference transmission time as a result of the comparison by the time comparison means and the time comparison means that compares the estimated transmission time calculated by the time calculation means with the reference transmission time And means for transmitting the transmission target data.

  In the present invention, if the communication speed of the received data exceeds the reference speed, the estimated transmission time required for data transmission is calculated, and if the calculated estimated transmission time is less than the reference transmission time, the transmission is higher than the reference transmission power. Since transmission is performed with power, if the amount of data to be transmitted is small enough to be less than the reference transmission time, there is less risk of excessive power consumption, so transmission that prioritizes smooth data transmission Control is performed.

  In addition, the wireless communication apparatus according to the present invention includes means for lowering transmission power from the reference transmission power when the communication speed of the received data is lower than the reference speed as a result of the comparison by the speed comparison means.

  In the present invention, when the communication speed of the received data is lower than the reference speed, the transmission power is reduced below the reference transmission power, so that the transmission power is prioritized to reduce power consumption. In other words, in a situation where the communication speed is lower than the reference speed, there is a low possibility that data can be transmitted reliably, so power is wasted by performing control that minimizes the power required for transmission. To prevent that.

  Furthermore, the wireless communication apparatus according to the present invention determines whether to transmit the transmission target data with a transmission power higher than the reference transmission power when the predicted transmission time exceeds the reference transmission time as a result of the comparison by the time comparison means. Means for performing a display screen output process capable of accepting the instruction, and when receiving an instruction to transmit to the display screen with a transmission power higher than the reference transmission power, with a transmission power higher than the reference transmission power. Means for transmitting data to be transmitted.

  In the present invention, when transmitting data having a data amount such that the predicted transmission time exceeds the reference transmission time, an output of a display screen that can accept an instruction as to whether or not to perform data transmission with high transmission power When processing is performed and an instruction to perform data transmission is received, data transmission is performed with transmission power higher than the reference transmission power, so that a scene for confirming the user's intention is secured and the amount of data reflecting the user's intention Large data transmission can be performed with high transmission power. That is, if a large amount of data is transmitted so that the expected transmission time exceeds the reference transmission time, the power consumption required for transmission increases. However, there are situations in which data transmission has the highest priority over suppression of power consumption. The transmission power can be controlled in consideration of the ease of use.

  Furthermore, when the wireless communication apparatus according to the present invention receives an instruction not to perform transmission with a transmission power higher than a reference transmission power on the display screen, the wireless communication apparatus reduces the transmission power from the reference transmission power and is a transmission target. A means for transmitting data is provided.

  In the present invention, when an instruction indicating that data transmission is not performed with high transmission power is received on the display screen for confirming the user's intention, data is transmitted with transmission power lower than the reference transmission power. Therefore, it is possible to control transmission power in consideration of usability for a user who wants to prioritize suppression of power consumption.

  Further, the wireless communication apparatus according to the present invention includes means for comparing the communication speed related to transmission with the reference speed during transmission of data to be transmitted with transmission power higher than the reference transmission power, and the communication speed related to transmission as a result of the comparison. Means for reducing the transmission power when the speed is lower than the reference speed.

  In the present invention, even if data transmission is once performed with the increased transmission power, the transmission power is reduced when the communication speed is reduced. Therefore, even when the communication situation deteriorates after the transmission starts, power is wasted. Can be prevented. In other words, in wireless communication, even after a physical obstacle suddenly intervenes between devices that are performing wireless communication, or when communication is started due to factors such as entering the back of a building due to the movement of a user carrying the wireless communication device. The wireless communication environment often changes. Therefore, if the wireless communication environment changes so that the communication speed decreases after data transmission is performed with increased transmission power, transmission processing should be performed with increased power consumption in a situation where it is difficult to reliably transmit data. Therefore, in such a case, in the present invention, the transmission power is automatically reduced to perform control giving priority to suppression of power consumption.

  Further, the wireless communication apparatus according to the present invention includes a power supply unit, a means for comparing the communication speed related to transmission with the reference speed during transmission of data to be transmitted with transmission power higher than the reference transmission power, and the result of the comparison, When the communication speed related to transmission is lower than the reference speed, means for comparing the remaining power amount of the power source mounted on the power source mounting unit with the reference remaining power amount, and as a result of comparison, if the remaining power amount is lower than the reference remaining power amount, the transmission power And a means for lowering.

  In the present invention, even if data transmission is performed with increased transmission power, if the communication speed is lower than the reference speed, the remaining power amount of the power source mounted in the power source mounting portion is compared with the reference remaining power amount, and the remaining power amount is the reference. When the remaining power is lower, the transmission power is reduced below the reference transmission power. Therefore, if the communication speed deteriorates after increasing the transmission power and performing data transmission, if there is not enough power so that the remaining power of the power source is lower than the reference remaining power, the remaining power is reduced by reducing the transmission power. Therefore, transmission power control suitable for securing the usage time of the portable wireless communication device can be performed.

In the present invention, if the communication speed of received data is high and the estimated transmission time required for data transmission is less than the reference transmission time, data transmission is performed with a transmission power higher than the reference transmission power. Data can be reliably transmitted at high speed after confirming that it is not consumed by transmission.
In the present invention, when the communication speed of received data is lower than the reference speed, the transmission power is reduced below the reference transmission power. Therefore, priority is given to the reduction of power consumption regardless of the amount of data to be transmitted. The transmission power control can be realized.

Furthermore, in the present invention, when transmitting data with a large amount of data, when a display output capable of accepting an instruction as to whether or not to transmit data with high transmission power is performed and an instruction for performing data transmission is accepted Since data transmission is performed with transmission power higher than the reference transmission power, transmission power can be controlled with priority given to data transmission in accordance with user convenience.
Furthermore, in the present invention, when an instruction operation indicating that data transmission is not performed with the increased transmission power is received with respect to a display output indicating whether or not to perform data transmission with the increased transmission power, Since data transmission is performed with the reduced transmission power, it is possible to realize transmission power control that prioritizes suppression of power consumption in accordance with user convenience.

In addition, in the present invention, when data transmission is performed at a higher transmission power and the communication speed decreases, the transmission power is reduced accordingly. It is possible to switch to control giving priority to suppression.
Furthermore, in the present invention, if the communication speed decreases after performing data transmission with the increased transmission power, the remaining power amount of the power source mounted on the power source mounting unit is compared with the reference remaining power amount, If the amount is small, the transmission power is reduced, so that it is possible to realize transmission power control that maintains a small amount of remaining power.

  FIG. 1 shows a main internal configuration of a portable music playback device 10 (corresponding to a wireless communication device) according to the first embodiment of the present invention. The portable music player 10 is characterized in that it has a wireless LAN communication function in addition to the original music playback function. The main module 11 that supports the music playback function is replaced with a wireless LAN module that supports the wireless LAN communication function. 20 is connected, and power is supplied to each of the modules 11 and 20 by a battery B (corresponding to a power source) attached to the battery attachment portion 38.

  The portable music player 10 can acquire (download) various music data by the wireless LAN communication function, and can reproduce and output the acquired music data by the main module 11 and can also transmit various data (such as acquired music data). Transmission to other communication devices via wireless LAN communication is also supported. In addition, the wireless LAN module 20 included in the portable music player 10 controls the transmission power so that it can be appropriately changed according to the wireless communication speed, the amount of data to be transmitted, etc., and ensures that data can be transmitted and received quickly. The power consumption can be prevented from increasing excessively. Hereinafter, the main module 11 and the wireless LAN module 20 of the portable music player 10 will be described.

  The main module 11 has a configuration in which a RAM 12, a ROM 13, a storage unit 14, an audio output processing unit 15, a main control unit (processor) 17, a display panel 18, and an operation unit 19 are connected through internal buses 11a and 11b. The RAM 12 temporarily stores data, files, and the like accompanying the processing of the main control unit 17. The ROM 13 stores in advance a playback program 13a defining control processing for music playback, a screen database 13b including various screen data to be displayed on the display panel 18 when performing various operations such as music selection and wireless LAN communication. .

  The file selection screen 45 in FIG. 3A shows an example of a display screen corresponding to one of a plurality of screen data included in the screen database 13b, and the display panel is displayed when the data to be transmitted is selected. 18 is displayed. The file selection screen 45 has a data file list 45a, a send button 45b, and a cancel button 45c in which file names indicating the respective data stored in the storage unit 14 of the main module 11 are selectably arranged. When an operation for selecting the send button 45b is performed in a state where any one file name is selected in the data file list 45 on the file selection screen 45, the data related to the file name is selected as a transmission target. It will be. When the cancel button 45c is selected, the process on the file selection screen 45 is canceled and the process returns to the operation stage before file selection.

  The transmission confirmation screen 46 in FIG. 3B also shows an example of a display screen corresponding to one of the plurality of screen data included in the screen database 13b, and transmits data with the transmission power maximized. It is displayed on the display panel 18 when it takes 150 seconds or more. The transmission confirmation screen 46 includes a word for confirming to the user whether or not to transmit data to be transmitted with the maximum transmission power, and includes a YES button 46a and a NO button 46b for receiving an instruction from the user. When the operation for selecting the YES button 46a is performed, processing for transmitting with the maximum transmission power is performed as described later, while when the operation for selecting the NO button 46b is performed, the transmission power is reduced. Processing to transmit is performed. In addition to the above, the screen database 13b includes data corresponding to various display screens. For example, display screen data for setting and inputting a communication destination (access destination, data transmission destination, etc.) Contains.

  Returning to FIG. 1, the storage unit 14 of the main module 11 stores various data such as music data acquired (received) via wireless LAN communication. The audio output processing unit 15 performs a process of reproducing and amplifying the music data stored in the storage unit 14 and outputting a sound corresponding to the music data from the speaker 16.

  The display panel 18 connected to the main control unit 17 displays a display screen (see FIGS. 3A and 3B) based on various screen data under the control of the main control unit 17. The operation unit 19 connected to the main control unit 17 includes a plurality of keys such as an up / down / left / right key and a determination key, and accepts a selection instruction operation from the user for a selection item such as a button on the display screen. Then, the contents of the received instruction operation are transmitted to the main control unit 17. The main control unit 17 controls the music data (for example, MP3 file music data) playback processing in accordance with the rules of the playback program 13a stored in the ROM 13, and performs various settings and the like. By the linkage processing with the LAN module 20, processing related to setting and input of wireless LAN communication is also performed.

  On the other hand, the wireless LAN module 20 performs wireless LAN communication (IEEE802.11, IEEE802.11a, IEEE802.11b, IEEE802.11g, IEEE802.11k, etc.) defined by the American Institute of Electrical and Electronics Engineers as a chip. A wireless LAN RF (high frequency) circuit unit 21 and a MAC (Media Access Control) processing unit 25.

  The RF circuit unit 21 corresponds to a physical layer in the OSI reference model, and is connected to an antenna 24 for wireless LAN that transmits and receives various signals, and performs frequency conversion, I / Q conversion, and built-in power in wireless communication access control. Various processes such as amplification of received signals in the amplifier unit are performed. The operations related to these processes are controlled by the CPU 27 included in the MAC processing unit 25. In particular, in this embodiment, when the RF circuit unit 21 performs the transmission processing of the transmission signal, the transmission power is controlled by the CPU 27. It has become so. That is, the RF circuit unit 21 includes a power control unit 21a that performs control to change transmission power at the time of transmission based on a control instruction of the CPU 27. The power control unit 21a is a value of transmission power instructed by the CPU 27. Perform transmission processing with. In addition, when the value instructed by the CPU 27 is changed even during transmission, the RF circuit unit 21 performs transmission processing by changing the transmission power to the changed value. The power control unit 21a sets the transmission power in the default state to 11 dBm, and changes the transmission power according to an instruction from the CPU 27 from the value in the default state.

  The RF circuit unit 21 also includes an intensity detection circuit 21b that detects a value related to the power intensity of a carrier wave (carrier) for wireless communication, and a C / N detection that detects a C / N ratio (carrier wave power / noise power) of the carrier. A circuit 21c is provided. The strength detection circuit 21b detects the power strength of the carrier in the range of about −80 dBm to −10 dBm.

  Next, the MAC processing unit 25 will be described. The MAC processing unit 25 has a configuration in which a memory 26, a CPU 27, a connection interface 28 for connecting to the main module 11, an RF connection interface 29 for connecting to the RF circuit unit 21, and the like are connected by an internal bus 25a. In wireless LAN communication, processing such as digital conversion / demodulation and access control is performed.

  FIG. 2 conceptually shows the contents of the CPU 27 functioning as the MAC layer 30 in the OSI reference model in the present embodiment, and such functions depend on the prescribed contents of the program P stored in the memory 26. It has been realized. The MAC layer 30 of the CPU 27 performs control processing according to an access method (for example, CSMA / CA) based on the IEEE (American Institute of Electrical and Electronics Engineers) wireless LAN standard (IEEE802.11 standard). Among them, Upper MAC 31 is included in the upper layer and Lower MAC 32 corresponding to the lower layer. Further, the Upper MAC 31 includes a CTS number detection block 31a and an AP number detection block 31b.

  The CTS number detection block 31 a detects the number of CTS receptions from other wireless devices that are received through the antenna 24 and the RF circuit unit 21. CTS means a signal transmitted to prevent confusion in wireless communication by a plurality of wireless devices. In the wireless LAN standard, CTS is used for receiving RTS (Request to Send transmission request signal) issued from an access point or the like. When a wireless device that is to start communication transmits a CTS (reception preparation completion signal) and the other wireless device receives the CTS, the other wireless device is refrained from communicating until the next communicable time. . Therefore, when the number of times of receiving CTS within a predetermined time is large, the situation of wireless communication at that place is high, and when the number of times of receiving CTS within a predetermined time is small, The state of wireless communication at that location is low in congestion.

  The AP number detection block 31b in the UpperMAC 31 detects the number of access points capable of wireless communication. Specifically, identification information (for example, SSID (Service Set Identifier)) included in a beacon signal transmitted at a fixed interval (for example, 500 msec) from the access point (AP) received by the antenna 24 and the RF circuit unit 21. Based on this, the access point that can be connected at the location is identified, and the number of access points is determined.

  The CPU 27 of this embodiment performs transmission power control processing based on the program P stored in the memory 26 in addition to the above-described processing corresponding to the wireless LAN communication function. That is, the CPU 27 specifies the value of the transmission power according to the control processing (the first flowchart in FIG. 5 and the second flowchart in FIG. 6) to be described later, and sends an instruction to perform transmission with that value to the power control unit 21a of the RF circuit unit 21. send. As a result, the portable music player 10 (wireless LAN module 20) performs transmission with the transmission power changed according to the communication speed (bit rate) and the amount of data to be transmitted. The details of the control process related to the transmission power of the CPU 27 will be described later.

  Further, the memory 26 shown in FIG. 1 corresponds to the program P, various reference values (reference speed 33, reference transmission time 34, reference remaining power 35, reference range 36) used in the transmission power control process, and various communication speed conditions. A power table 40 that defines the value of the attached transmission power is stored.

  The reference speed 33 among the various reference values stored in the memory 26 is a threshold value used for comparison with the communication speed of received data. When the communication speed of the received data exceeds the reference speed 33, the CPU 27 determines that the communication speed at that time is high (the bit rate (bps) is high), and when the communication speed of the received data is equal to or less than the reference speed 33, The CPU 27 determines that the communication speed at that time is low (bit rate (bps) is low). In this embodiment, a value of 1/8 of the maximum bit rate of the RF circuit unit 21 of the wireless LAN module 20 is used as the value of the reference speed 33, but other values (for example, 1 of the maximum bit rate) are used. It is also possible to use a value of / 7).

  The reference transmission time 34 is a threshold value that is compared with an estimated transmission time required for completion of transmission of data to be transmitted, and is set to 150 seconds in this embodiment. As the reference transmission time 34, a value from n seconds to n × 3 seconds (n is a value within 60 seconds) can be applied in addition to 150 seconds. Furthermore, the reference remaining power level 35 is a threshold value to be compared with the remaining power level of the battery B mounted on the battery mounting unit 38. In the present embodiment, a value corresponding to 1/4 of the total capacity of the battery B is applied. (Other values are also applicable). Furthermore, the reference range 36 is a threshold value that is compared with a fluctuation range of the communication speed of received data over a certain time (difference between the maximum communication speed and the minimum communication speed), and a predetermined numerical value (for example, an average communication speed). Of 20%).

  FIG. 4 shows the contents of the power table 40 stored in the memory 26. The power table 40 is a content in which each value of transmission power is associated according to the level of the current communication status. Specifically, the first level is 15 dBm, the second level is 12 dBm, and the third level is 10 dBm. , 9 dBm is associated with the fourth level. The first level basically corresponds to a good communication situation where the bit rate is stable and the bit rate is high, and the second level is an average in an unstable state in which the fluctuation of the communication speed within a certain time exceeds the reference range 36. This corresponds to a normal communication situation where a high bit rate is high. The third level corresponds to a bad communication situation where the average bit rate is low in an unstable state in which the fluctuation of the communication speed within a certain time exceeds the reference range 36, and the fourth level is a stable bit. Corresponds to the communication limit at the communication limit where the rate is low. Note that the value of the transmission power associated with each level is merely an example, and various values can be applied according to the product features, specifications, and the like.

  The concept of the set value of the transmission power for each level in the power table 40 of the present embodiment is as follows. First, since the first level where the wireless communication status is “good” is likely to be able to transmit data smoothly, priority is given to transmitting the target data quickly, and transmission is performed at the maximum power (15 dBm). Like to do. Further, the second level in which the wireless communication status is “medium” has a high average bit rate, but the communication speed is unstable, so the transmission power (12 dBm) slightly lower than the maximum power is used as the data. It tries to balance the prompt transmission and suppression of increase in power consumption.

  Furthermore, the third level in which the wireless communication status is “bad” is that the average bit rate is low and the communication speed is unstable, so that rapid data transmission cannot be expected. 10 dBm is associated with the transmission power with emphasis on. Furthermore, the fourth level where the wireless communication status is “communication limit” corresponds to the limit bit rate that wireless communication can be used regularly, and the possibility that the communication destination can reliably receive the transmission data is very low. The transmission power is lowered (9 dBm), and the highest priority is given to the suppression of power consumption required for transmission. The power table 40 is created by adjusting the reference transmission power (reference transmission power) to the default value (11 dBm) of the power control unit 21a of the RF circuit unit 21, and corresponds to the first level and the second level. The attached transmission power is higher than the reference transmission power, and the transmission power associated with the third level and the fourth level is lower than the reference transmission power.

  Next, a control process related to data transmission by wireless LAN communication performed by the CPU 27 based on the program P stored in the memory 26 will be described. First, when an operation instruction for data transmission is received from the user via the operation unit 19, the fact is transmitted from the main module 18 to the CPU 27, and the CPU 27 first displays an image for setting and inputting a data transmission destination. Is output to the main control unit 17. When the transmission destination setting input is completed, the CPU 27 outputs an instruction to display the file selection screen 45 shown in FIG.

  When the selection of data to be transmitted on the file selection screen 45 is completed, the CPU 27 performs a process of establishing a wireless communication connection with an accessible access point in order to transmit the data to the transmission destination set and input. Accordingly, when various data are received from the access point, the communication speed (bps) of the received data is continuously detected as necessary for a certain period (for example, 3 seconds). Further, the CPU 27 calculates a difference between the lowest communication speed and the highest communication speed among the communication speeds detected for a certain period, and uses the calculated difference as a value for determining the stability of the communication status.

  The first flowchart shown in FIG. 5 shows the procedure of the control process performed by the CPU 27 after calculating the communication speed difference. The CPU 27 stores the reference range in which the calculated communication speed difference is stored in the memory 26. The stability of the communication status is determined based on whether or not it is below 36 (S1). When the calculated difference does not fall below the reference range 36 (when the calculated difference is greater than or equal to the reference range 36), the CPU 27 determines that the communication status is not stable due to a large bit rate variation (S1: NO), and the CPU 27 Calculates the average communication speed based on each detected communication speed (S2), and compares the calculated average communication speed with the reference speed 33 stored in the memory 26 to determine whether the average communication speed exceeds the reference speed 33 or not. Is determined (S3).

  When the average communication speed exceeds the reference speed 33 (S3: YES), the CPU 27 stores the power table 40 stored in the memory 26 because the communication status is unstable and the average bit rate corresponds to the second level. With reference to the transmission power value (12 dBm) associated with the second level, the transmission power is set to 12 dBm and the transmission target data is transmitted (S4). Further, when the average communication speed does not exceed the reference speed 33 (S3: NO), the CPU 27 corresponds to the third level in which the average bit rate is low in an unstable communication state. With reference to the transmission power value (10 dBm) associated with the level, the transmission power is set to 10 dBm and the transmission target data is transmitted (S12).

  In the first stage of the first flowchart, when the CPU 27 determines that the calculated communication speed difference is below the reference range 36 and the communication state is stable (S1: YES), the CPU 27 next The communication speed related to the detected reception is compared with the reference speed 33, and it is determined whether or not the communication speed exceeds the reference speed 33 (S5). When the communication speed does not exceed the reference speed 33, that is, when the communication speed is equal to or less than the reference speed 33 (S5: NO), the communication state is stable and corresponds to the fourth level with a low bit rate. A process of transmitting the transmission target data by referring to the transmission power value (9 dBm) associated with the fourth level and setting the transmission power to 9 dBm lower than the default state (11 dBm) (transmission power to the power control unit 21a) (S6) A process for outputting an instruction to set the signal to 9 dBm is performed (the same applies hereinafter).

  On the other hand, when the latest communication speed exceeds the reference speed 33 (S5: YES), the CPU 27 further determines the amount of data to be transmitted selected on the file selection screen 45 in FIG. On the basis of the communication speed, a predicted transmission time required to complete transmission of data to be transmitted is calculated (S7). Note that the predicted transmission time is obtained by dividing the amount of data to be transmitted by the communication speed. Then, the CPU 27 compares the calculated predicted transmission time with the reference transmission time 34 stored in the memory 26, and determines whether or not the predicted transmission time is less than the reference transmission time 34 (S8).

  When the predicted transmission time is less than the reference transmission time 34 (S8: YES), since the data amount of the transmission target data is not large, the CPU 27 increases the transmission power from the default state, and the maximum associated with the first level. Is transmitted at a transmission power of 15 dBm (S9). When the predicted transmission time is equal to or longer than the reference transmission time 34 (S8: NO), the CPU 27 performs output control processing for displaying the transmission confirmation screen 46 shown in FIG. 3B on the display panel 18 (S10), It is determined whether or not an instruction to transmit data to be transmitted with the maximum transmission power is received from the user (S11).

  When the YES button 46a is operated on the transmission confirmation screen 46 and an instruction to transmit at the maximum transmission power is received (S11: YES), the CPU 27 is associated with the first level reflecting the user's intention. Data transmission is performed with the maximum transmission power (15 dBm) (S9). In addition, when the NO button 46b is operated on the transmission confirmation screen 46 and an instruction operation not to transmit at the maximum transmission power is received (S11: NO), the CPU 27 uses the transmission power (10 dBm) lower than the default state. Transmission is performed (S12), and control giving priority to suppression of increase in transmission power accompanying long-time transmission is performed.

  Further, the second flowchart shown in FIG. 6 transmits the data to be transmitted with the maximum transmission power (15 dBm) in the first flowchart of FIG. 5 (S9), and based on the provisions of the program P during the data transmission. The process procedure which CPU27 performs is shown. During the data transmission, the CPU 27 detects the communication speed related to the transmission at any time, compares the detected communication speed with the reference speed 33, and determines whether the communication speed is lower than the reference speed 33 (S20).

  When the communication speed does not fall below the reference speed 33 (S20: NO), that is, when the reference speed is 33 or more, the communication status is stable and the bit rate is high, so the CPU 27 maximizes the transmission power (15 dBm). The control process of maintaining and transmitting is continued (S21). On the other hand, when the communication speed is lower than the reference speed 33 (S20: YES), the communication status is deteriorated compared to the start of transmission, and it is difficult to transmit data smoothly. Is given priority, and the CPU 27 performs a control process of reducing the transmission power from 15 dBm to 10 dBm (S22). After the data transmission control at 15 dBm (S21) or after the data transmission control at 10 dBm (S22), the CPU 27 determines whether the data transmission is completed (S23). When the data transmission is not completed (S23: NO), the process returns to the first stage (S20) again, and the CPU 27 compares with the reference speed 33, while when the data transmission is completed (S23: YES), the CPU 27 Ends a series of transmission control processes.

  As described above, the portable music player 10 of the present embodiment is stably provided by the CPU 27 of the wireless LAN module 20 performing the above-described control processing according to the communication speed and the data amount of data to be transmitted. If the bit rate (communication speed) is high and the amount of data to be transmitted is small, the transmission is performed with the maximum power, so that data can be transmitted smoothly. Furthermore, when the bit rate is stable and high, but the amount of data to be transmitted is large, the portable music playback device 10 displays the transmission confirmation screen 46 in FIG. Since it is confirmed to the user whether the transmission can be performed, it is possible to perform a control process reflecting the user's intention as to whether transmission is performed at the maximum power or transmission power is reduced in order to reduce power consumption.

  Also, if the bit rate is stable and low, the possibility that data can be transmitted reliably is low. Therefore, the portable music player 10 reduces the transmission power to the communication limit (9 dBm), thereby reducing the power consumption required for transmission. You can prioritize the suppression of

  Furthermore, even when the communication status is unstable and the average bit rate is high or low, the portable music player 10 performs control to change the value of the transmission power as appropriate according to the communication status, so that smooth It is possible to control data transmission and power consumption required for transmission in a well-balanced manner according to communication conditions. Furthermore, even when data transmission is performed at the maximum power, as shown in the second flowchart of FIG. 6, if the communication status deteriorates, the portable music player 10 decreases the transmission power. It can be adjusted so that the power consumption accompanying data transmission does not become excessive in response to changes.

  In addition, this invention is not limited to the form of the portable music player 10 mentioned above, There exist various modifications. For example, in this embodiment, the level based on the state of the communication speed is divided into four levels as shown in FIG. 4, but the number of levels is the specification of the portable music player 10 (wireless LAN module 20), In addition, it can be appropriately increased or decreased depending on the grade and the like.

  It is also possible to link the remaining power amount of the battery B attached to the battery attachment unit 38 of the portable music player 10 and the control of the transmission power. In this case, the remaining power amount of the battery B detected by the remaining power detection unit (not shown) provided in the battery mounting unit 38 shown in FIG. 1 is transmitted to the CPU 27, and the CPU 27 By comparing the reference remaining power 35 stored in the memory 26, it is determined whether or not the remaining power is lower than the reference remaining power. In the case of performing such a modification, the process of the modification related to the CPU 27 needs to be defined by the program P stored in the memory 26, and the process related to the remaining power is the process shown in the second flowchart of FIG. And will do it as an alternative.

  The third flowchart shown in FIG. 7 shows a processing procedure of a modified example regarding the control of transmission power performed by the CPU 27 in accordance with the remaining power of the battery, and the third flowchart of this modified example is replaced with the second flowchart. This is processing subsequent to transmission of data to be transmitted with the maximum transmission power (15 dBm) (S9 in the first flowchart shown in FIG. 5).

  In the third flowchart, during the data transmission, the CPU 27 detects the communication speed related to the transmission at any time and compares the detected communication speed with the reference speed 33 to determine whether the communication speed is lower than the reference speed 33. (S30). When the communication speed does not fall below the reference speed 33 (S30: NO), as in the case of the second flowchart, the CPU 27 continues the control process of transmitting while maintaining the transmission power at the maximum (15 dBm) (S31). On the other hand, when the communication speed is lower than the reference speed 33 (S30: YES), the CPU 27 compares the remaining power amount of the battery B transmitted from the battery mounting unit 38 with the reference remaining power amount 35, and the remaining power amount is the reference remaining power amount 35. It is judged whether it is less than (S32).

  If the remaining power does not fall below the reference remaining power 35 (S32: NO), the battery B has sufficient power for transmission, so the CPU 27 continues to transmit at the maximum transmission power (15 dBm). A control process is performed (S31). When the remaining power is lower than the reference remaining power 35 (S32: YES), priority is given to the suppression of the power consumption of the battery B, and the CPU 27 performs a control process for transmitting by reducing the transmission power from 15 dBm to 10 dBm (S33). . After the data transmission control at 15 dBm (S31) or after the data transmission control at 10 dBm (S33), the CPU 27 determines whether the data transmission is completed (S34), and the data transmission is not completed (S34: NO), the process returns to the first stage (S20), and when the data transmission is completed (S34: YES), the CPU 27 ends the series of transmission control processes. By performing the transmission power control in cooperation with the remaining power amount of the battery B in this way, the CPU 27 can contribute to maintaining the power supply by the battery B of the portable music player 10 as long as possible.

  Further, the wireless LAN module 20 related to the wireless communication function of the portable music player 10 according to the present embodiment is incorporated in the portable music player 10, but in addition to being incorporated in such a device, a personal computer It can also be incorporated into information processing devices such as PDAs and television devices, and various devices such as mobile phones and portable image display devices, and can also be configured as an independent wireless communication device. Good. For example, the device of the present invention may be configured in a card shape corresponding to various connection standards (PCMCIA standard, CF card standard, USB standard, IEEE 1394, etc.) and connected to various information processing apparatuses. Furthermore, the wireless communication targeted by the wireless communication apparatus of the present embodiment is not limited to a wireless LAN, but for various wireless communication such as Wireless USB, UWB (Ultra Wide Band), BLUETOOTH (registered trademark), and the like. Is also applicable.

It is a block diagram which shows the main internal structures of the portable music player which concerns on embodiment of this invention. It is a block diagram showing the content which CPU functions as a MAC layer. (A) is the schematic which shows a file selection screen, (b) is the schematic which shows a transmission confirmation screen. It is a chart which shows an electric power table. It is a 1st flowchart which shows the process sequence which concerns on transmission power control. It is a 2nd flowchart which shows the process sequence in the time of the data transmission with maximum electric power. It is a 3rd flowchart which shows the process sequence of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Portable music player 11 Main module 20 Wireless LAN module 21 RF circuit part 21a Power control part 25 MAC processing part 26 Memory 27 CPU
33 Reference speed 34 Reference transmission time 35 Reference remaining power 36 Reference range 38 Battery mounting part 40 Power table 46 Transmission confirmation screen B Battery P Program

Claims (6)

In a wireless communication apparatus that controls transmission power based on the communication speed of received data related to wireless communication,
Speed comparison means for comparing the communication speed of received data with a reference speed;
As a result of the comparison by the speed comparison means, when the communication speed of the received data exceeds a reference speed, a time calculation means for calculating an estimated transmission time required for completion of transmission of the transmission target data based on the communication speed;
Time comparison means for comparing the predicted transmission time calculated by the time calculation means with a reference transmission time;
A wireless communication apparatus comprising: means for transmitting transmission target data with a transmission power higher than a reference transmission power when a predicted transmission time is less than a reference transmission time as a result of comparison by the time comparison means.   The wireless communication apparatus according to claim 1, further comprising means for lowering transmission power from reference transmission power when a communication speed of received data is lower than a reference speed as a result of comparison by the speed comparison means. If the predicted transmission time exceeds the reference transmission time as a result of the comparison by the time comparison means, the display screen output process is capable of accepting an instruction as to whether or not to transmit the transmission target data with a transmission power higher than the reference transmission power. Means for
Or a means for transmitting data to be transmitted with a transmission power higher than a reference transmission power when an instruction to transmit with a transmission power higher than a reference transmission power is received on the display screen. Item 3. The wireless communication device according to Item 2.   The apparatus according to claim 3, further comprising means for transmitting the transmission target data by lowering the transmission power below the reference transmission power when an instruction not to perform transmission with a transmission power higher than the reference transmission power is received on the display screen. The wireless communication device described. Means for comparing the communication speed for transmission with the reference speed during transmission of data to be transmitted with a transmission power higher than the reference transmission power;
The wireless communication apparatus according to any one of claims 1 to 4, further comprising: means for reducing transmission power when a communication speed related to transmission is lower than a reference speed as a result of comparison. A power supply unit;
Means for comparing the communication speed for transmission with the reference speed during transmission of data to be transmitted with a transmission power higher than the reference transmission power;
As a result of the comparison, when the communication speed for transmission is lower than the reference speed, means for comparing the remaining power amount of the power source mounted on the power source mounting unit with the reference remaining power amount,
The wireless communication device according to any one of claims 1 to 4, further comprising: means for reducing transmission power when a remaining power amount is lower than a reference remaining power amount as a result of the comparison.

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