An enhanced BP secondary decoding algorithm

When the traditional LT code is used for encoding and decoding, if there is no encoded packets with degree 1 in the remaining encoded groups, the decoding will stop and the decoding cannot be continued. That will affects the decoding efficiency. For this reason, this paper proposes an improved enhanced decoding method. When BP decoding stops, the remaining coded packets will be decoded using the secondary decoding method, which can improves the success rate of decoding.