A Differential Detection Technique for Local Services in DAB Single Frequency Networks
Fabian Schrieber · 2019
Digital Audio Broadcasting (DAB) is a widely used terrestrial audio broadcast transmission system. DAB employs Orthogonal Frequency-Division Multiplexing which allows the operation in a Single Frequency Network (SFN). SFNs are beneficial for the distribution of services in large areas, but do not support local services, i.e. different services from different transmitters, without distortion. However, some audio service providers rely on local services. A Local Service Insertion technique for DAB SFNs that supports existing receivers was developed, tested and presented in a field trial in Braunschweig, Germany. The results showed some co-channel interference between local services for existing receivers that use conventional differential detection (CDD). In this paper, we investigate an iterative decision-directed differential detection technique with channel equalization to combat the remaining co-channel interference. An increase in robustness against co-channel interference of about 3 dB is found in comparison to CDD.