A Fountain Coding-Based Method for Guaranteeing the Secure Transmission of Multimedia Multicast

Abstract

The invention discloses a fountain-coding-based method for ensuring the multicast security transmission of multimedia. The method comprises the steps of 1) dividing the to-be-transmitted multimedia service flow into k information packets; 2) within a current transmission interval Ts, coding an information packet corresponding to the transmission interval at a base station based on the fountain-coding method to obtain a validation packet; 3) within the current transmission interval Ts, broadcasting the validation packet obtained in the step 2) to the users of a multicast group by the base station; 4) adding the validation packet successfully received by the first user of the multicast group into a successfully received validation packet set by the base station, decoding the validation packet successfully received by the first user at the same time, and adding the decoded information into a decoded information packet sequence number set Di; 5) repeating the steps 2), 3) and 4) till the transmission completion of the k formation packets; 6) completing the transmission of the multimedia service flow upon detecting k sequence numbers in the decoded information packet sequence number set. The fountain-coding-based method is high in transmission efficiency, high in security and high in reliability.

Description

technical field [0001] The invention belongs to the field of wireless communication, and relates to a method for ensuring the safe transmission of multimedia multicast based on fountain coding. Background technique [0002] With the popularity of wireless multimedia terminals in cellular networks, people's demand for wireless multimedia services and applications is increasing day by day, some of which are required by multiple users at the same time, such as video conferencing, mobile TV, and microblog release , mobile online games, etc. As the number of users increases, this type of service will consume a large amount of air interface resources, which will increase its cost and seriously hinder the development and popularization of new services. Therefore, wireless multi- Broadcast technology provides a good development opportunity for the development of multimedia services in cellular networks. [0003] Wireless multicast refers to the simultaneous transmission of multime...

AI Technical Summary

Problems solved by technology

There are a large number of multicast users in the multicast system. They need the same high-quality multimedia data, but due to factors such as different distribution locations, occlusion and multipath fading, their channel quality may vary greatly. At this time, in order to ensure fairness , the sender chooses a lower modulation and coding method to transmit multicast data at a low rate to ensure that the multicast service can cover as many services as possible; in other words, in a multicast system, users with poor channel conditions greatly limit the number of Spectrum Efficiency of Broadcasting System

At the same time, due to the influence of the time-varying fading channel, the sending end cannot guarantee that all users can receive each data symbol accurately, and the receiving end will face the problem of packet loss.

In order to ensure reliable transmission, these lost packets need to be fed back and retransmitted, but because the multicast system is a multi-user system, the packet loss of each user may occur in different time slots, so multiple users may lose different packets, but A large number of feedback processes will seriously occupy system resources, and may even cause "feedback storm" to interrupt normal information transmission

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