JP2003198618A - Packet data communication system, portable telephone set and network side equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain image deterioration to a minimum by restoring dropped-out packet data from other packet data, when packet data are dropped out during communication, in TV telephone and dynamic picture distribution in portable telephone using IP packet network. <P>SOLUTION: Data synthesized by data synthesis/isolation equipment 7 are turned into a packet by packeting equipment 8. Parity data are formed for each group by an XOR engine 9. The packet is transmitted together with the parity data by a radio communication part 10. When the packet is received and the dropping-out of packet data is generated, the dropped-out packet data are regenerated from other packet data and the parity data by the XOR engine 9. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention restores the data of a lost packet from other packet data when a packet is lost during communication in a videophone or a moving image distribution in a mobile phone using an IP packet network. Thus, the present invention relates to a method for minimizing image deterioration.

[0002]

2. Description of the Related Art Generally, in transmission in a mobile phone and an IP packet network, in addition to a received packet code error, packet discard due to congestion in the IP network and packet loss due to deterioration of transmission quality in a wireless section occur. There is.

In order to transmit voice data requiring real-time characteristics on an IP network, RTP (Real-time) is used.
e Transport Protocol),
The real-time property is guaranteed, and the data of the missing packet is complemented inside the voice codec.

Similarly, moving images and image data of TV phones are also RT.
Although it is made into P packets, when a missing packet occurs, a specific image frame may be omitted, or when data is complemented, it may be rough.

FIG. 5 shows a conventional embodiment. In FIG. 5, 1 is a mobile phone, 2 is a microphone built in the mobile phone, 3 is a speaker, 4 is an encoder / decoder for converting audio data, 5 is a video camera for a videophone, and 6 is image data. Encoder / decoder, 7 is a synthesizing / separating device that synthesizes / separates audio data and image data, 8 is a device that packetizes data, 10 is a wireless communication unit, 11 is a wireless base station, and 12 is a wireless base station control device. ,
13 is a gateway connecting the mobile terminal network and the IP network, 14
Is an IP network.

Next, the operation will be described. When performing communication by videophone, the voice received by the microphone 2 is converted into data by the voice encoder / decoder, and at the same time the camera 5
The video image captured in (1) is also converted into data by the image data encoder / decoder and sent to the image data synthesizing / separating device 7. The image data synthesizer / separator 7 synthesizes the audio data and the image data, and the packetizer 8 packetizes them. The RTP is also implemented in the IP packet in the packetizer 8.

The data packetized by the packetizing device 8 is sent to the mobile telephone network through the wireless communication section 10. The transmitted data is IP through the gateway 13.
It is sent to the network 14 as an IP packet. During this time, packet data loss occurs in the mobile phone network (particularly the wireless communication part) and the IP network.

Next, the operation inside the cellular phone on the receiving side when packet data is lost will be described. Figure 6
Then, the operation when the packet data is actually lost in the IP network or the mobile phone network during the voice call is shown. When the packetizer 8 determines that the packet data received by the mobile phone 1 is missing, the audio data encoder / decoder 4 complements the missing data to generate audio data and reproduce the audio from the speaker 3. To do.

FIG. 7 shows the operation when an IP packet is lost during a videophone call. When the received data is missing, the data is complemented like the voice, but the image is disturbed, and in the worst case, one frame of the moving image may be missing.

[0010]

[Problem to be Solved by the Invention] Conventional voice codec
In the case of performing data complementation by technology, there were many cases where voice quality did not become a problem even if data complementation occurred to some extent. However, T
When video such as V-phone, video distribution, and digital TV reception is received as packet data by a mobile phone, data complementation and image frame dropout can be seen in a form that is clearly deteriorated by human eyes.

Further, when data matching is performed by retransmitting a lost packet or the like, a videophone or a digital telephone is used.
It was difficult to realize with a moving image such as a TV, which requires real-time performance.

The present invention has been made to solve the above problems. The object of the present invention is to provide a mobile phone and an IP.
It is an object of the present invention to provide a technique for minimizing the quality deterioration of a moving image due to a data error and packet loss occurring in the packet network, a data error in a wireless section of a mobile phone and a continuous packet data loss in a packet network. .

[0013]

A packet data communication system according to the present invention is a packet data communication system that divides data including video and audio into packet data for communication, and when transmitting the data. , When the parity data is generated for each group including a plurality of packet data, the parity data is also transmitted, and the packet data is lost in the group when receiving the data, the received group is received. The missing packet data is reproduced from the other packet data in the group and the received parity data of the group.

In the packet data communication system, when transmitting the data, the order of the packet data to be transmitted is changed, and when receiving the data, the order of the received packet data is changed before the transmission is changed. It is characterized by returning to the state.

The packet data communication system is characterized by being a mobile phone.

The packet data communication system is a gateway device for a mobile phone system.

The mobile telephone according to the present invention receives a plurality of packets and parity data transmitted from a communication partner, and a transmitter for transmitting the parity data generated for each of a plurality of packets together with the plurality of packets. In any one of the plurality of packets is missing, a receiving unit for reproducing the missing packet based on the packet other than the missing packet and the parity data among the plurality of packets It is characterized by

The network-side device according to the present invention receives the plurality of packets and the parity data transmitted from the communication partner side, the transmitting unit transmitting the parity data generated for each of the plurality of packets together with the plurality of packets. In this case, when any of the plurality of packets is missing, a receiving unit that reproduces the missing packet based on a packet other than the missing packet and the parity data of the plurality of packets is provided. It is characterized by including.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. First, the present invention will be outlined. In the packet communication system according to the present invention, a group is formed for each certain unit when a moving image is distributed to an IP packet network, XOR is calculated for each group to generate parity data, and this parity data is used as a data group. It is sent at the same time as when it is sent, and if any packet data on the receiving side does not reach the receiving side due to packet discard or data error due to congestion, or if it cannot be used, it is missing from other data and parity data in this group. By reproducing the data, loss of image data is eliminated.

Further, since packet data is likely to be continuously lost in the wireless section, the transmission order of the packet data of the image data is exchanged, and even if continuous loss occurs, the transfer data is grouped by unit. If viewed, the adjustment is made so that one packet is lost, and finally, the lost data is reproduced from the parity data.

The first embodiment will be described below with reference to the drawings. In FIG. 1, 1 is a mobile phone, 2 is a microphone built in the mobile phone, 3 is a speaker, 4 is an encoder / decoder for converting audio data, 5 is a video camera for a TV phone, and 6 is image data. Encoder / decoder, 7 is a synthesizing / separating device for synthesizing / separating audio data and image data, 8 is a device for packetizing data, 9 is an XOR engine for calculating XOR of data in arbitrary group units, and 10 is wireless A communication unit, 11 is a radio base station, 12 is a radio base station control device, 13 is a gateway connecting a mobile terminal network and an IP network, and 14 is an IP network. The radio base station 11, the radio base station control device 12, or the gateway 13 corresponds to, for example, a network side device.

Next, the operation will be described. The operation will be described along the flow of data in the case of performing communication by the TV phone. On the data transmission side, the sound received by the microphone 2 is converted into data by the audio encoder / decoder, and at the same time, the image captured by the camera 5 is also encoded by the image data encoder / decoder.
Convert to data with a decoder.

After that, the two data are composed of image data
It is sent to the separation device 7. The image data synthesizer / separator 7 synthesizes the audio data and the image data. After that, the packetizing device 8 converts the data into an arbitrary packet size.
For the packetized data, parity data is generated for each group unit that is arbitrarily set in the XOR engine 9, and the wireless controller 10 to the wireless base station 11 and the base station controller 12, as parity packet data, for each group.
It is transmitted to the IP network through the gateway 13.

On the data receiving side, the data received from the IP network is entered from the gateway 13, the base station controller 12, and the wireless base station 11 into the wireless controller 10 of the mobile phone 1 and XOR'd.
Whether or not there is data loss is checked for each group unit that is arbitrarily set in the engine 9, and when the data loss occurs, the data that has been lost from the parity data is reproduced, and the packetizing device 8 and the image data combining / The separation device separates the audio and image data, and the audio and video data are converted by the audio and image encoder / decoders, respectively.

FIG. 2 is a diagram for explaining data generated by the operation of the XOR engine unit 9. In FIG. 2, 20 is a group of arbitrarily set IP packets, 21 is parity data generated from the group of IP packets, and 22 is X.
An OR calculator, 23 is a group of IP packets received by the receiving side terminal, 24 is packet data missing in the group in the received IP packet, 25 is a reproduced parity packet data group, and 26 is a reproduced IP packet. is there.

Next, the operation will be described. Mobile phone 1
The parity data 21 is generated in the XOR engine for each arbitrary group unit set in the above. The generated parity data is added to the end of a normal IP packet. When the packet data 24 is lost in the IP network 14 due to congestion or the like, the XOR engine reproduces the missing parity data from the other packet data and the parity data, and reproduces a group of normal packet data.

FIG. 3 shows an example in which the transmission order of data is changed in order to cope with continuous data loss in the wireless section and the resistance to continuous data loss is increased. In FIG. 3, 3
0 is an arbitrary data group that generates parity data,
Reference numeral 31 is data in which the data transmission order is changed when transmitting, 32 is received data, and 33 is a data string continuously lost at the time of reception.

Next, the operation will be described. As in the case of FIG. 2, parity data is generated in arbitrary group units, and the data transmission order is changed in arbitrary group units.
The data of the data group 30 is 3 in the XOR engine 9.
As shown in 1, the data transmission order is exchanged and then divided and transmitted.

When an error occurs in the wireless section of the mobile phone, data loss occurs continuously. In FIG. 3, the missing data 33 in the received data 32 continuously occurs. When data loss is detected, all the data is reproduced by waiting for the parity data transmitted later and reproducing the lost data by the XOR engine. After reproducing the data, the data is replaced in the original order to reproduce all the data.

As described above, according to the present invention, data can be reproduced even when a packet is lost. By limiting the range of packet exchange, it is possible to minimize the effect of delay when transmitting and receiving real-time video.

Embodiment 2. Embodiment 2 of the present invention will be described below with reference to the drawings. In FIG. 4, reference numeral 40 is a PC connected to the Internet, and 41 is an IP telephone connected to the Internet.

Next, the operation will be described. The method of transmitting the moving image of the TV phone and the data flow are the same as those in the first embodiment. In this embodiment, a method for realizing communication with an existing IP TV phone on the Internet and an S / W IP TV phone on a PC will be described. The XOR engine part of the mobile phone is mounted in the gateway 13 of the mobile phone network, and when transmitting to the IP network, only conventional data is transmitted to enable communication with the existing system in the IP network.

[0033]

As described above, according to the present invention, the parity data is generated and transmitted in an arbitrary group unit at the time of transmitting the packet data. Therefore, even if a part of the packet data is lost due to the influence of the congestion or the wireless section, It is possible to reproduce the missing packet data.

Further, when the moving image data is transmitted / received, if it is missing, a clear moving image can be viewed without causing image distortion due to data complement or correction.

Since the data transmission order is changed, the resistance to continuous loss can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram for explaining an operation concept of an XOR engine unit of the present invention.

FIG. 3 is a diagram for explaining an operation concept of data rearrangement according to the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 5 is a block diagram showing a schematic configuration diagram of a conventional embodiment.

FIG. 6 is a diagram for explaining the operation of the conventional embodiment.

FIG. 7 is a diagram for explaining the operation of the conventional example. 1
Mobile phone, microphone built into mobile phone, 3
Speaker, encoder that converts 4 voice data
Decoder, 5 TV phone video camera, 6 Encoder / decoder for converting image data, 7 Synthesizing / separating device for synthesizing / separating audio data and image data, 8
Device for packetizing data, 9 XOR engine for calculating XOR of data in arbitrary group units, 10 wireless communication unit, 11 wireless base station, 12 wireless base station control device, 13 gateway connecting mobile terminal network and IP network, 1
4 IP networks, 20 groups of arbitrarily set IP packets, 21 parity data generated from groups of IP packets, 22 XOR calculator, 23 groups of IP packets received by the receiving terminal, 24 received IPs
Packet data missing in groups in packet, 25
Reproduced parity packet data group, 26
Reproduced IP packet, 30 Arbitrary data group for generating parity data, 31 Data in which the data transmission order is changed when transmitting, 32 received data, 33 data string continuously lost upon reception, 40 P
C, 41 IP phone.

Claims (6)

[Claims] 1. A packet data communication system that divides data including video and audio into packet data for communication, and when transmitting the data, generates parity data for each group including a plurality of packet data. However, when packet data is lost in the group when transmitting the parity data together and receiving the data, the parity of the other packet data in the received group and the received packet data in the group is received. A packet data communication system characterized by reproducing lost packet data from data. 2. The packet data communication system, when transmitting the data, changes the order of packet data to be transmitted, and when receiving the data, changes the order of received packet data when transmitting. The packet data communication system according to claim 1, wherein the packet data communication system returns to a previous state. 3. The packet data communication system according to claim 1, wherein the packet data communication system is a mobile phone. 4. The packet data communication system according to claim 1, wherein the packet data communication system is a gateway device for a mobile phone system. 5. A transmitting unit for transmitting parity data generated for each of a plurality of packets together with the plurality of packets, and a plurality of the packets when receiving the plurality of packets and the parity data transmitted from a communication partner side. A mobile phone, comprising: when any one of the plurality of packets is missing, a receiving unit that reproduces the missing packet based on a packet other than the missing packet and the parity data among the plurality of packets. 6. A transmission unit for transmitting parity data generated for each of a plurality of packets together with the plurality of packets, and a plurality of the packets when receiving the plurality of packets and the parity data transmitted from a communication partner side. A network-side device including a receiver for reproducing the missing packet based on a packet other than the missing packet and the parity data among the plurality of packets when any one of the packets is missing.