JP2007096982A - Information transmitting apparatus, transmission condition control method and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information transmitting apparatus, convenient for users, capable of selecting at a transmitting side an appropriate transmission route in accordance with a transmission state of a communication path without feeding back the transmission status of the communication path from a receiving side to the transmitting side. <P>SOLUTION: Encoding is performed in accordance with a transmission rate instruction from a transmission rate determination section 26. In a transmission section 24, a transmission wait buffer used for transmitting encoded data is present but an activity ratio of the transmission wait buffer is acquired by a communication path state estimation section 25 as communication state information. In the communication path state estimation section 25, on the basis of a predetermined relationship of a transmission wait buffer activity ratio and a communication path state value, the communication path state value is outputted to the transmission rate determination section 26. In the transmission rate determination section 26, a transmission rate corresponding to the communication path state is determined from the acquired communication path state value and the predetermined relationship of communication path state value and transmission rate, and outputted to an encoding section 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an information transmission apparatus including a communication module having a communication function conforming to, for example, Bluetooth (registered trademark) and the like, and a transmission condition control system in the apparatus, and more particularly, estimation of a transmission path state on a data transmission side. The present invention relates to an information transmission apparatus and a transmission condition control method for determining an encoding parameter at the time of data transmission based on the result.

  Conventionally, in an information communication apparatus that transmits data through a communication path, there has been a technique for ensuring data transmission with a desired quality by changing communication parameters according to the state of the transmission path.

For example, the method disclosed in Japanese Patent Application Laid-Open No. 2004-72720 includes a step of notifying the transmission terminal of feedback information indicating the transmission state of the communication path from the reception terminal to the transmission side based on the notified information. A method for changing the transmission rate when transmitting the message is shown.
Japanese Patent Laid-Open No. 2004-72720

  However, the conventional technology described above requires a mechanism for returning feedback information indicating the transmission state of the communication path from the receiving terminal to the transmitting terminal, and the transmitting side and the receiving side need to be provided with the above mechanism in advance. There is.

  Here, for example, in the case of a communication protocol related to Bluetooth audio transmission, which is a communication method using the 2.4 GHz ISM band, feedback information indicating the transmission state of the communication path as shown in the conventional method is received from the receiving side. The mechanism to return to the sending side is not an essential implementation item, but it is left to the implementation at the discretion of the receiving side.

  For this reason, in the case of the communication protocol related to Bluetooth audio transmission, there may be a case where the above-described conventional method cannot be applied. Users of the system suffer from the inconvenience of being unable to do so.

  The present invention has been made in consideration of such circumstances, and appropriate transmission according to the transmission state of the communication path on the transmission side without performing feedback on the transmission state of the communication path from the reception side to the transmission side. It is an object of the present invention to provide an information transmission device that enables selection of a rate and is convenient for a user.

  In order to solve the above-described problem, in the information transmission apparatus according to the first aspect of the present invention, a transmission unit that transmits data to another apparatus via a wireless communication path, and a communication path state that estimates the state of the wireless communication path To satisfy the transmission rate determined by the estimation unit, the transmission rate determination unit that determines the transmission rate that is the data transmission amount per unit time according to the state estimated by the channel state estimation unit, and the transmission rate determination unit And an encoding processing unit for encoding data.

  Further, in the information transmitting apparatus of the invention according to claim 2, the transmission unit includes a transmission waiting buffer that temporarily holds the data before transmission, and the communication path state estimation unit uses the transmission waiting buffer usage rate. Based on the above, the state of the wireless communication path is estimated.

  Furthermore, in the information transmitting apparatus of the invention according to claim 3, the channel state estimation unit estimates the state of the radio channel based on the number of data retransmissions per unit time.

  According to a fourth aspect of the present invention, there is provided a transmission condition control method comprising: a transmission step for transmitting data to another device via a wireless communication channel; a communication channel state estimation step for estimating the state of the wireless communication channel; A transmission rate determination step for determining a transmission rate, which is a data transmission amount per unit time according to the state estimated in the path state estimation step, and encoding the data so as to satisfy the transmission rate determined by the transmission rate determination step And an encoding process step.

  Furthermore, in the transmission condition control method of the invention according to claim 5, the communication channel state estimation step estimates the state of the wireless communication channel based on a usage rate of a transmission waiting buffer that temporarily holds data before transmission. It is characterized by.

  Furthermore, the transmission condition control method of the invention according to claim 6 is characterized in that the channel state estimation step estimates the state of the radio channel based on the number of data retransmissions per unit time.

  According to a seventh aspect of the present invention, there is provided a recording medium on which a computer-readable program is recorded, wherein the program transmits a data to another apparatus via a wireless communication path, and a wireless step. A channel state estimation step for estimating a channel state, a transmission rate determination step for determining a transmission rate that is a data transmission amount per unit time according to the state estimated in the channel state estimation step, and a transmission rate determination And an encoding process step for encoding data so as to satisfy the transmission rate determined by the steps.

  According to the present invention, it is possible to select an appropriate transmission rate according to the transmission state of the communication path on the transmission side without a mechanism for notifying feedback information indicating the transmission state of the communication path from the receiving terminal to the transmitting terminal, Therefore, it is possible to provide an information transmission apparatus convenient for the user, which can ensure data transmission of the above quality.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the situation when this method is applied will be described with reference to FIG. The two terminals shown in FIG. 1 can be considered to transmit audio data using this method, and here, as an example, audio data 11 transmitted wirelessly from an audio player 10 is transmitted to wireless headphones 12. It is an example that assumes a usage scene to receive and listen to.

  An example will be described on the assumption that the information transmission apparatus of this system is mounted on the audio player 10 side. Here, the description will be made on the premise of wireless communication based on Bluetooth, for example, but the present embodiment is not limited to wireless communication including Bluetooth, and is applicable to wired communication with cable connection. Is possible.

  Next, the functional configuration of this method will be described with reference to FIG.

  The transmission terminal 21 encodes the audio data 11 and transmits it to the reception terminal 27. In the receiving terminal 27, the media data received by the transmission unit 28 is decoded by the decoding unit 29, and then output by the headphone speaker or the like in the output unit 2A.

  Details of the internal configuration of the transmission terminal 21 are as follows. The input unit 22 acquires audio data from an audio playback function unit (not shown) of the audio player.

  The acquired audio data is encoded by the encoding unit 23 by a predetermined encoding method. The encoded data is transmitted from the transmission unit 24 to the Bluetooth wireless transmission path.

Encoding is performed according to a transmission rate instruction from the transmission rate determination unit 26.
Here, the transmission rate instruction is determined as follows. The transmission unit 24 has a transmission waiting buffer that is used when transmitting encoded data. The communication path state estimation unit 25 acquires the usage rate of the transmission waiting buffer as communication state information.

The communication channel state estimation unit 25 outputs the communication channel state value to the transmission rate determination unit 26 from the relationship between the predetermined transmission waiting buffer usage rate and the communication channel state value.
The transmission rate determination unit 26 determines a transmission rate according to the communication channel state from the acquired communication channel state value based on a predetermined relationship between the communication channel state value and the transmission rate, and outputs the transmission rate to the encoding unit 23.

  With this mechanism, encoded data encoded at an appropriate transmission rate according to the communication state can be transmitted.

  FIG. 3 shows a flowchart of the channel state estimation process, and FIG. 4 shows a flowchart of the transmission rate determination process.

  Next, FIG. 5 shows an example of the relationship between the transmission waiting buffer usage rate and the communication path state, which is used in the communication path state estimation unit 25.

  In this example, it is considered that the actual transmission rate is close to the maximum transmission rate possible at the present time because the usage rate of the transmission waiting buffer is high. The communication path state value is smaller than when the wait buffer usage rate is low.

  As an operation of the channel state estimation unit 25, for example, a configuration in which the channel state is estimated from the number of data retransmissions per unit time and the channel state value is output as shown in FIG. 6 is possible.

  This idea is based on the fact that the number of data retransmissions performed when the frequency of occurrence of transmission errors in the channel is high increases the channel state estimation, and the number of data retransmissions per unit time increases. As a result, the communication path state is judged to be worse and a smaller communication path state value is output.

  FIG. 7 shows an example of the relationship between the communication path state value and the transmission rate used in the transmission rate determination unit 26.

  In this example, the communication path condition is poor, that is, the smaller the value, the smaller the transmission rate, allowing a good transmission by giving a margin to the maximum transmission rate that can be transmitted on the communication path at present. I'm thinking about doing that.

  As shown in Case 1 (73) and Case 2 (74) in FIG. 7, various relationships are possible between the communication path state value and the transmission rate.

  The relationship shown in Case 2 is that the maximum bit rate determined from the coding method specifications is sufficiently lower than the transmittable bit rate when the channel state is good, and even if the channel state value is somewhat low, there is a margin at the maximum bit rate. An example used when it can be transmitted is shown.

  Here, the operation in the transmission terminal 21 described above is performed with the hardware configuration shown in FIG. 8, for example.

  A general control unit is configured by the CPU 81, the ROM 82, and the RAM 83 in FIG. 8, and the individual functional units such as the wireless communication unit 84, the user interface unit 85, and the sound input unit 86 are controlled in an integrated manner. Function is realized.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, you may delete a some component from all the components shown by embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

The use condition explanatory drawing which concerns on embodiment of this invention. Explanatory drawing which concerns on embodiment of this invention. The flowchart figure of the channel state estimation process which concerns on embodiment of this invention. The flowchart figure of the transmission rate determination process which concerns on embodiment of this invention. Usage situation explanatory diagram according to an embodiment of the present invention The flowchart figure of the channel state estimation process which concerns on embodiment of this invention. FIG. 6 is a diagram illustrating a predetermined correspondence relationship between a communication path state and a transmission rate according to the embodiment of the present invention. The schematic block diagram of the transmission terminal which concerns on embodiment of this invention.

Explanation of symbols

21 Transmission terminal 22 Input unit 23 Encoding unit 24 Transmission unit 25 Channel state estimation unit 26 Transmission rate determination unit 27 Reception terminal 28 Transmission unit 29 Decoding unit 2A Output unit

Claims (7)

A transmission unit for transmitting data to other devices via a wireless communication path;
A channel state estimation unit for estimating the state of the wireless channel;
A transmission rate determining unit that determines a transmission rate that is a data transmission amount per unit time according to the state estimated by the channel state estimating unit;
An information transmitting apparatus comprising: an encoding processing unit that encodes the data so as to satisfy the transmission rate determined by the transmission rate determining unit. The transmission unit further includes a transmission waiting buffer that temporarily holds the data before transmission,
The information transmission apparatus according to claim 1, wherein the communication path state estimation unit estimates the state of the wireless communication path based on a usage rate of the transmission waiting buffer. The information transmission apparatus according to claim 1, wherein the communication channel state estimation unit estimates the state of the wireless communication channel based on the number of data retransmissions per unit time. A transmission condition control method in an information transmission apparatus,
A transmission step of transmitting data to another device via a wireless communication path;
A channel state estimation step for estimating the state of the wireless channel;
A transmission rate determination step for determining a transmission rate that is a data transmission amount per unit time according to the state estimated in the communication channel state estimation step;
A transmission condition control method comprising: an encoding processing step for encoding the data so as to satisfy the transmission rate determined by the transmission rate determination step. 5. The transmission condition according to claim 4, wherein the communication path state estimation step estimates the state of the wireless communication path based on a usage rate of a transmission waiting buffer that temporarily holds the data before transmission. Control method. 5. The transmission condition control method according to claim 4, wherein the channel state estimation step estimates the state of the wireless channel based on the number of data retransmissions per unit time. In a recording medium on which a computer-readable program is recorded,
The program is
A transmission step of transmitting data to another device via a wireless communication path;
A channel state estimation step for estimating the state of the wireless channel;
A transmission rate determination step for determining a transmission rate that is a data transmission amount per unit time according to the state estimated in the communication channel state estimation step;
A recording medium comprising: an encoding process step for encoding the data so as to satisfy the transmission rate determined in the transmission rate determination step.

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