Symbol detection based on Voronoi surfaces with emphasis on superposition modulation

• Main Authors: Martin Damrath, Peter Adam Hoeher, Gilbert J.M. Forkel
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2017-08-01
• Series: Digital Communications and Networks
• Subjects: Digital modulation; Demodulation; Detection algorithms; Linear approximation
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352864817300263

A challenging task when applying high-order digital modulation schemes is the complexity of the detector. Particularly, the complexity of the optimal a posteriori probability (APP) detector increases exponentially with respect to the number of bits per data symbol. This statement is also true for the Max-Log-APP detector, which is a common simplification of the APP detector. Thus it is important to design new detection algorithms which combine a sufficient performance with low complexity. In this contribution, a detection algorithm for two-dimensional digital modulation schemes which cannot be split-up into real and imaginary parts (like phase shift keying and phase-shifted superposition modulation (PSM)) is proposed with emphasis on PSM with equal power allocation. This algorithm exploits the relationship between Max-Log-APP detection and a Voronoi diagram to determine planar surfaces of the soft outputs over the entire range of detector input values. As opposed to state-of-the-art detectors based on Voronoi surfaces, a priori information is taken into account, enabling iterative processing. Since the algorithm achieves Max-Log-APP performance, even in the presence of a priori information, this implies a great potential for complexity reduction compared to the classical APP detection.