Transmission method and system for VOLTE video call

Abstract

The invention relates to the technical field of information and discloses a transmission method and system for a VOLTE video call. The method comprises the following steps that a receiving end receives a data package of the VOLTE video call and sends feedback information to a sending end, wherein the feedback information is a receiving state of the data package; the sending end judges whether packet loss exists according to the received feedback information; and if yes, the lost data package is retransmitted. Through the method, the sending end can check whether the packet loss exists, and when the packet loss exists, the reliable and quick data retransmission is realized, so that the overall delay and the system overhead are reduced.

Description

technical field [0001] The invention relates to the field of information technology, in particular to a VOLTE video phone transmission method and system thereof. Background technique [0002] VOLTE (Voice over LTE, video phone over LTE) video phone service is one of the core services of 4G communication, and it is also a major functional improvement different from traditional call services. Among them, VOLTE is an IP data transmission technology, and video data uses RTP ( Real-time Transport Protocol, Real-time Transport Protocol) transmission, control information is transmitted through RTCP (RTPControl Protocol, Real-time Transport Control Protocol), and SIP (Session Initiation Protocol, Session Initiation Protocol) is used to negotiate video transmission parameters. Different from general video streaming services, video telephony services focus on real-time interactivity, which means that the transmission delay must be strictly controlled, and a long data buffer cannot be ...

AI Technical Summary

Problems solved by technology

But these methods still have limitations:

If it is found that the data packet has not been received for more than the specified time, it will be judged as packet loss, which will cause the normal playback time of the data packet to be close to or exceed the normal playback time of the data packet when the packet loss is found. In addition, the feedback message is waiting for the data to be retransmitted, resulting in video delay. The time is too large (may reach a few seconds); if the data packet sequence number is found to be wrong and the retransmission is immediately fed back, then this seems to reduce the retransmission delay, but because the data packets are only out of order rather than packet loss, thus Too many feedback messages will eventually cause the sender to initiate a lot of unnecessary data retransmissions, which will cause bandwidth tension, further packet loss, and eventually spend more time on data retransmissions

[0005] Second, packet loss information cannot be fed back reliably

RTCP is used for out-of-band retransmission. In the VOLTE video telephony service, the RTCP bandwidth needs to be negotiated in advance, and is usually very low, which means that RTCP messages cannot be sent arbitrarily. It is difficult to estimate how much information needs to be fed back, which may cause RTCP packet loss. The packet loss information is usually only fed back once, and once the packet is lost, it will affect the retransmission effect

For in-band retransmission, although there is no bandwidth problem when using the video channel to return messages, RTP itself will also lose packets, so the feedback message may still be unable to be delivered to the sender due to data packet loss.

[0006] Third, the system overhead is large

Whether it is in-band or out-of-band feedback, the receiver usually only feeds back information after packet loss occurs, so the sender can only know what data the receiver has lost, but cannot know what data has been received or has been played.

As a result, the sender can only cache as many video data packets that have been sent as possible, so as to ensure that the corresponding data packets can be retransmitted when receiving the packet loss feedback message

However, due to the high video stream and large amount of data, a large amount of cached data will occupy too much system memory, especially in an embedded environment where the memory capacity is inherently limited, and may cause running errors due to insufficient memory.

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