Coding/decoding method and device for fountain codes

Abstract

The invention discloses a coding / decoding method for fountain codes. The coding method comprises the following steps: dividing raw data blocks into different information layers in the descending order of priority; precoding each information layer at the same code rate, connecting the obtained coded layers in a cascade mode, and sending to a priority LT coder to carry out LT coding; and in the coding process, dynamically adjusting the size of the input symbol set of each code symbol according to the adjustment parameter, and controlling the unequal protection degrees of data in different priorities. The decoding method comprises the following steps: a priority LT decoder decodes the received coded data packet to obtain output data with unequal error protection functions; a data diverter divides the output data into different coded layers according to the number of layer; and each coded layer is respectively sent into the corresponding precoding decoder to decode the precoding, thereby restoring each information layer. The invention also discloses a coding / decoding device for fountain codes. By using the invention, video can be efficiently and reliably transmitted in a layered multicasting environment.

Description

technical field [0001] The invention relates to the technical field of error control in network transmission, in particular to a fountain code encoding and decoding method and device. Background technique [0002] For heterogeneous networks or heterogeneous terminals, in multimedia multicast transmission, because each receiver has different bandwidth and channel conditions, layered coding technology is usually used to enable receivers to receive more and more data to improve the reconstructed video quality. Receivers may experience better video quality as the performance of network conditions improves, and even receivers with poor channel conditions can watch basic reconstructed videos. However, even for receivers with good channel conditions, the quality of the reconstructed video may be seriously degraded because layered encoded data is very sensitive to packet loss in transmission, for example: during the transmission of layered encoded data , the loss of low-level pack...

AI Technical Summary

Problems solved by technology

[0005] 1. The number of encoded symbols sent is limited; for receivers with limited bandwidth or poor channel conditions, if a small part of the encoded data is not received, due to the avalanche decoding effect of the fountain code, the iterative decoder can only Reconstructs a small portion of the transmitted video chunks so that the basic playback quality of the video cannot be guaranteed

[0006] 2. The existing standard fountain coding is a coding method based on an equal error protection mechanism. However, layered video transmission requires a FEC technology based on an unequal error protection mechanism due to the different importance of its layered bit stream data. Therefore, the existing standard fountain coding cannot meet the needs of layered video transmission

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