Self-synchronizing pulse position modulation with error tolerance

TL;DR

This paper introduces a coding theoretic variation of pulse position modulation (PPM) that enhances synchronization and error correction, making PPM more robust against synchronization loss and environmental noise.

Contribution

The paper proposes a novel self-synchronizing PPM scheme with a dedicated synchronization layer, compatible with existing PPM techniques, and introduces a generalized expurgated PPM for improved error correction.

Findings

Enhanced synchronization and error correction in PPM.

Compatibility with existing PPM techniques.

Generalized PPM as a standalone error-correcting scheme.

Abstract

Pulse position modulation (PPM) is a popular signal modulation technique which creates M-ary data by means of the position of a pulse within a time interval. While PPM and its variations have great advantages in many contexts, this type of modulation is vulnerable to loss of synchronization, potentially causing a severe error floor or throughput penalty even when little or no noise is assumed. Another disadvantage is that this type of modulation typically offers no error correction mechanism on its own, making them sensitive to intersymbol interference and environmental noise. In this paper we propose a coding theoretic variation of PPM that allows for significantly more efficient symbol and frame synchronization as well as strong error correction. The proposed scheme can be divided into a synchronization layer and a modulation layer. This makes our technique compatible with major existing techniques such as standard PPM, multipluse PPM, and expurgated PPM as well in that the scheme can be realized by adding a simple synchronization layer to one of these standard techniques. We also develop a generalization of expurgated PPM suited for the modulation layer of the proposed self-synchronizing modulation scheme. This generalized PPM can also be used as stand-alone error-correcting PPM with a larger number of available symbols.