Direct- or Fast-Access Decoding Schemes for VF Codes

Abstract

In this paper, we propose two schemes, which enable any VF code to realize direct- or fast-access decoding for any long source sequence. Direct-access decoding means that any source symbol of any position can be directly decoded within constant time, not depending on the length of source sequence N, without decoding the whole codeword sequence. We also evaluate the memory size necessary to realize direct-access decoding or fast-access decoding with decoding delay O(log log N), O(log N), and so on, in the proposed schemes.