JP2008072599A - Radio communication terminal, communicating system, band control method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure a band and maintain a conversation by changing a bit rate of audio data for the adjustment of the amount of transfer data. <P>SOLUTION: In a radio communication terminal 1 (800), a band of a network 600 as a communication network is calculated from a loss ratio of a sound data packet to/from a radio communication terminal 3 (820), and the bit rate of wireless data is lowered based on this computation result. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for controlling a communication band in IP-based voice communication using a wireless communication terminal.

  A state of a use band used in conventional wireless communication will be described with reference to FIG. In the figure, in the state of section T1, since communication between wireless communication terminals does not exceed the bandwidth upper limit at the access point, the conversation is normally continued.

  However, there are the following problems in the state of the use band used in the conventional wireless communication. When multiple wireless communication terminals are connected to the same access point and perform voice communication, the bandwidth limit at the access point is exceeded and the bandwidth required for communication cannot be secured, resulting in significant delays and lost packets. It means that you can't talk properly.

Here, a video / audio transmitter and a video / audio receiver for transmitting / receiving data including video and audio data at a predetermined bit rate are provided, and the video / audio receiver is based on a signal from the video / audio transmitter. The video / audio transmitter includes a transmission unit that transmits data while variably controlling the bit rate based on the communication status detected by the video / audio receiver. Even if the communication state deteriorates by temporarily reducing the bit rate and transmitting the data to the video / audio receiver when the communication state does not satisfy a predetermined standard, In addition, there has been proposed a technique capable of performing data communication while minimizing degradation of video and audio data and without reducing the quality of the entire video and audio to be transmitted (see, for example, Patent Document 1). .
Japanese Patent Laid-Open No. 2005-006288

  However, in the above-described conventional technology, a plurality of terminals use an access point in wireless communication, so that packet loss and delay increase, making a call difficult.

  The present invention has been made to solve the above-described problems. The purpose is to adjust the data transfer amount based on the information obtained from the sender information and receiver information of the voice session protocol, and to change the bit rate of the audio data, thereby reducing the bandwidth of the voice. To keep the call going.

  The invention according to claim 1 is a wireless communication terminal characterized in that a bandwidth of a communication network is calculated from a loss rate of voice data packets, and a bit rate of wireless data is lowered based on the calculation result.

  According to a second aspect of the present invention, in the wireless communication terminal according to the first aspect, the bit rate is gradually reduced.

  According to a third aspect of the present invention, in the wireless communication terminal according to the first or second aspect, the bit rate is reduced to a value calculated as a bit rate that can be realized from a data size that stabilizes a communication state.

  In a fourth aspect of the present invention, a wireless communication terminal connected via a network to a management server that performs call control calculates a bandwidth of a communication network from a loss rate of a voice data packet, and based on the calculation result A communication system characterized by lowering the bit rate of wireless data.

  The invention according to claim 5 has a step of calculating the bandwidth of the communication network from the loss rate of the voice data packet and a step of reducing the bit rate of the radio data based on the calculation result. It is.

  The invention according to claim 6 is the band control method according to claim 5, characterized in that the bit rate is gradually lowered.

  According to a seventh aspect of the present invention, in the bandwidth control method according to the fifth or sixth aspect, the bit rate is reduced to a value calculated as a bit rate that can be realized from a data size that stabilizes the communication state.

  The invention described in claim 8 is a program characterized by causing a computer to realize the function described in any one of claims 1 to 3.

  According to the present invention, based on the information obtained from the sender information and the receiver information of the voice session protocol, the data transfer amount is adjusted and the bit rate of the audio data is changed, thereby reducing the voice intelligibility. But it can secure bandwidth and keep the call going.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a communication system using a wireless LAN in the present embodiment is shown. In the figure, the call control management server 500 manages the position of the wireless communication terminal, the call session of the wireless communication terminal, and the like.

  The wireless communication terminals 1 to 4 have at least a call control protocol and a voice session protocol as a stream control and a program for managing the call session and the voice session.

  Referring to FIG. 2, there is shown a detailed configuration of functional blocks for realizing voice communication of the wireless communication terminals 1 to 4 shown in FIG. In the figure, a voice communication AP 100 realizes voice communication with an AP including an audio control unit 110 that controls an audio device, a stream monitoring unit 120 that monitors a stream state, and a communication session management unit 130 that manages a communication session. To do.

  The audio control unit 110 sets a codec type, a sampling rate, a bit rate, and the like, and performs audio device control of voice communication.

  The communication session management unit 130 manages a call session and a voice session that are currently in stream communication.

  The stream monitoring unit 120 monitors the stream state of the voice session managed by the communication session management unit 130, and determines the stream state from the sender information transmitted by the voice session protocol and the receiver information of the receiving communication partner. Monitor. The bandwidth of the current communication network is calculated from the lost rate of the voice data packet, and the data size per unit time is reduced by lowering the bit rate for the audio control unit 110, and the bandwidth of the communication network used by itself is reduced. Let

  The basic functions and configurations of the network 600, the access points 700 and 710, and the wireless communication terminals 800 to 830 in FIG. 1 are well known to those skilled in the art, and detailed description of the configurations is omitted.

  Note that one access point may be used as an access point for network connection. Further, the call control management server 500 can be configured by an information processing apparatus such as a SIP server, for example.

  Next, the operation of voice communication in the present embodiment shown in FIG. 1 will be described using the time chart shown in FIG.

  FIG. 3 shows a state of a use band of the access point 700 when the wireless communication terminal 1 (800) and the wireless communication terminal 3 (820) of FIG. 1 are performing voice communication.

  The upper limit of the communication band of the access point to which the wireless communication terminal 1 (800) belongs is Lmax. If this upper limit is exceeded, communication packet delays and lost will occur.

  The communication information of the wireless communication terminal 1 (800) and the wireless communication terminal 3 (820) is exchanged between both terminals, and at least both of them can know the number of packets transmitted to the other party. It is assumed that information indicating the number of received packets is included.

  In the section T1, the wireless communication terminal 1 (800) is performing voice communication with the wireless communication terminal 3 (820), and the use band of the access point is used up to L1.

  As shown in FIG. 4, when the number of transmission packets from the wireless communication terminal 1 (800) to the wireless communication terminal 3 (820) in the section T1 is 4 packets as in the data communication image, a certain time t ( The information of the wireless communication terminals 1 (800) and 3 (820) exchanged by SR, PR) is the number of transmission packets 2 as transmission information from the wireless communication terminal 1 (800) to the wireless communication terminal 3 (820). The number of packets is 2 as reception information from the wireless communication 3 (820) to the wireless communication terminal 1 (800).

  In section T2, if the wireless communication terminal 2 (810) starts voice communication with the wireless communication terminal 4 (830) and the required bandwidth of the access point 700 is L2, the use bandwidth has exceeded the upper limit Lmax. In addition, the communication state of the wireless communication terminal 1 (800) to the wireless communication terminal 4 (830) becomes unstable. Since the communication information of the wireless communication terminal 1 (800) and the wireless communication terminal 3 (820) at this time is the information of the received packet number 1 or 0 with respect to the information of the transmission packet number 2 from FIG. 1 (800) detects a communication band shortage.

  In the wireless communication terminal 1 (800), a loss of half of the number of transmitted packets has occurred from the reception information from the wireless communication terminal 3 (820), so the transmission data size is set to the current bit rate. The bit rate is changed from the data size to a data size of 1/2 or less, and communication is continued. Similarly, the wireless communication terminal 2 (810), the wireless communication terminal 3 (820), and the wireless communication terminal 4 (830) also change the bit rate.

  Generally, when the bit rate is lowered, the intelligibility of the voice is lowered, but the data size is also reduced, so that the use band can be reduced.

  By such an action, at t (SPRR) in the section T3, the number of packets of received information can be maintained with respect to the number of packets of transmitted information of 2, and the intelligibility can be lowered but voice communication can be continued without a sense of incongruity.

  According to the present embodiment described above, since the real-time packet transmission information and reception information are used, the bandwidth state at that time can be detected.

  In addition, since the voice data size is reduced by changing the bit rate, the clarity of the voice is lowered, but the response speed of the conversation so far can be maintained.

  Further, since the data size is controlled only by the wireless communication terminal, it can be realized without using another device dedicated to bandwidth control.

  Next, a second embodiment of the present invention will be described. The basic configuration is the same as that of the first embodiment, but the data size is further reduced. The method configuration is shown in FIG.

  In the figure, at T2δ, the reduction of the data size is gradually decreased so as not to give a sense of incongruity to the conversation.

  Thus, in this embodiment, since the reduction of the data size is gradually reduced, the effect that the conversation can be continued without a sense of incongruity is obtained.

  Each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the scope of the present invention. For example, a process for realizing the functions of each device may be performed by causing each device to read and execute a program for realizing the functions of the call control management server 500 and each wireless communication terminal. Further, the program is transmitted to another computer system by a transmission wave via a computer-readable recording medium such as a CD-ROM or a magneto-optical disk, or via a transmission medium such as the Internet or a telephone line. Also good.

It is a figure which shows the structure of the communication system in the 1st Embodiment of this invention. It is a functional block diagram which implement | achieves the voice communication of the radio | wireless communication terminal in the 1st Embodiment of this invention. It is a figure which shows the state of the use band of an access point when the radio | wireless communication terminals in the 1st Embodiment of this invention are performing voice communication. It is a figure which shows the packet data number per unit time in the 1st Embodiment of this invention. It is a figure which shows the state of the use band of an access point when the radio | wireless communication terminals in the 2nd Embodiment of this invention are performing voice communication.

Explanation of symbols

500 Call control management server 600 Network 700, 710 Access point 800-830 Wireless communication terminal

Claims (8)

  A wireless communication terminal that calculates a bandwidth of a communication network from a loss rate of a voice data packet and lowers a bit rate of wireless data based on the calculation result.   The wireless communication terminal according to claim 1, wherein the bit rate is gradually reduced.   3. The wireless communication terminal according to claim 1, wherein the bit rate is lowered to a value calculated as a bit rate that can be realized from a data size that stabilizes a communication state.   A wireless communication terminal connected via a network to a management server that performs call control calculates the bandwidth of the communication network from the loss rate of the voice data packet and reduces the bit rate of the wireless data based on the calculation result. A featured communication system.   A bandwidth control method comprising a step of calculating a bandwidth of a communication network from a loss rate of a voice data packet, and a step of lowering a bit rate of wireless data based on the calculation result.   6. The bandwidth control method according to claim 5, wherein the bit rate is gradually lowered.   7. The bandwidth control method according to claim 5, wherein the bit rate is lowered to a value calculated as a bit rate that can be realized from a data size that stabilizes a communication state.   A program for causing a computer to realize the function according to any one of claims 1 to 3.

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