Successive Interference Cancellation for Bandlimited Channels with Direct Detection

TL;DR

This paper compares receiver structures for bandlimited channels with direct detection, showing that successive interference cancellation (SIC) offers near-optimal rates with lower complexity, especially in fiber-optic channels, and enhances energy efficiency.

Contribution

It introduces SIC as a practical alternative to joint detection and decoding, demonstrating its effectiveness in fiber-optic channels with various modulation schemes and complexity reduction techniques.

Findings

SIC achieves rates close to joint detection and decoding (JDD).

Gibbs sampling reduces detector complexity at low to intermediate SNR.

Simulations confirm energy gains with SIC and Gibbs sampling.

Abstract

The maximum information rates for bandlimited channels with direct detection are achieved with joint detection and decoding (JDD), but JDD is often too complex to implement. Two receiver structures are studied to reduce complexity: separate detection and decoding (SDD) and successive interference cancellation (SIC). For bipolar modulation, frequency-domain raised-cosine pulse shaping, and fiber-optic channels with chromatic dispersion, SIC achieves rates close to those of JDD, thereby attaining significant energy gains over SDD and intensity modulation. Gibbs sampling further reduces the detector complexity and achieves rates close to those of the forward-backward algorithm at low to intermediate signal-to-noise ratio (SNR) but stalls at high SNR. Simulations with polar codes, higher-order modulation, and multi-level coding confirm the predicted gains.