Modular Arithmetic Erasure Channels and Their Multilevel Channel Polarization
This study proposes a novel channel model called the modular arithmetic erasure channel, which is a general type of arbitrary input erasure-like channels containing the binary erasure channel (BEC) and some other previously-known erasure-like channels. For this channel model, we give recursive formulas of Arıkan-like polar transforms to simulate its channel polarization easily. In other words, similar to the polar transforms for BECs, we show that the synthetic channels of modular arithmetic erasure channels are again equivalent to the same channel models with certain transition probabilities, which can be easily calculated by explicit recursive formulas. We also show that Arıkan-like polar transforms for modular arithmetic erasure channels behave multilevel channel polarization, which is a phenomenon appeared in the study of non-binary polar codes, and thus, modular arithmetic erasure channels are informative toy problems of multilevel channel polarization. Furthermore, as a solution of an open problem in non-binary polar codes for special cases, we solve exactly and algorithmically the limiting proportions of partially noiseless synthetic channels, called the asymptotic distribution of multilevel channel polarization, for modular arithmetic erasure channels.
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