The paper proposes an improved error-resilient Lempel-Ziv77 (LZ77) algorithm employing an adaptive amount of parity bits for error protection. It is a modified version of error resilient algorithm LZRS77, proposed recently, which uses a constant amount of parity over all of the encoded blocks of data. The constant amount of parity is bounded by the lowest-redundancy part of the encoded string, whereas the adaptive parity more efficiently utilizes the available redundancy of the encoded string, and can be on average much higher. The proposed algorithm thus provides better error protection of encoded data. The performance of both algorithms was measured. The comparison showed a noticeable improvement by use of adaptive parity. The proposed algorithm is capable of correcting up to a few times as many errors as the original algorithm, while the compression performance remains practically unchanged.
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