Joint Write-Once-Memory and Error-Control Codes

TL;DR

This paper introduces a joint coding scheme for write-once memory that combines capacity-achieving polar WOM codes with error-control capabilities, suitable for noisy real-world memory systems.

Contribution

It generalizes polar WOM codes to include error control by establishing conditions under which the scheme is effective in noisy environments.

Findings

The scheme is effective in most practical noisy memory scenarios.

A necessary and sufficient condition for the coding's effectiveness is derived.

High entropy sets for noisy channels are contained within those for test channels.

Abstract

Write-Once-Memory (WOM) is a model for many modern non-volatile memories, such as flash memories. Recently, several capacity-achieving WOM coding schemes have been proposed based on polar coding. Due to the fact that practical computer memory systems always contain noises, a nature question to ask next is how may we generalize these coding schemes, such that they may also have the error-control capabilities. In this paper, we discuss a joint WOM and error-control coding scheme, which is a generalization of the capacity-achieving WOM codes based on source polarization. In this paper, we prove a sufficient and necessary condition for the noisy reading channel being less noisy than the test channel in data encoding in the polar WOM coding. Such a sufficient and necessary condition is usually satisfied in reality. As a consequence of the sufficient and necessary condition, the high entropy set related to the noisy channel is usually strictly contained in the high entropy set related to the test channel in data encoding. Therefore the low-complexity polar joint WOM and error-control codes are sufficient for most practical coding scenarios.