Explicit and Efficient Constructions of Coding Schemes for the Binary Deletion Channel and the Poisson Repeat Channel
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This work gives an explicit construction of a family of error correcting codes for the binary deletion channel and for the Poisson repeat channel. In the binary deletion channel with parameter p (BDC_p) every bit is deleted independently with probability p. A lower bound of (1-p)/9 is known on the capacity of the BDC_p<cit.>, yet no explicit construction is known to achieve this rate. We give an explicit family of codes of rate (1-p)/16, for every p. This improves upon the work of Guruswami and Li <cit.> that gave a construction of rate (1-p)/120. The codes in our family have polynomial time encoding and decoding algorithms. Another channel considered in this work is the Poisson repeat channel with parameter λ (PRC_λ) in which every bit is replaced with a discrete Poisson number of copies of that bit, where the number of copies has mean λ. We show that our construction works for this channel as well. As far as we know, this is the first explicit construction of an error correcting code for PRC_λ.
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