Performance Comparison of Hierarchical Modulation Receiver Concepts for Different Service Classes

A narrowband transmission chain using conven- tional quadrature amplitude modulation (QAM) and soft- decoding is extended to implement hierarchical modulation. Packet error rate (PER) for different receiver concepts and mod- ulation schemes is investigated using a multipath channel model. Two different data service classes are considered, a high priority (HP) voice stream and a low priority (LP) data stream striving for maximum throughput. Furthermore, the paper describes how hierarchical modulation is adjusted adaptively according to the channel conditions to increase the performance, i.e. the amount of successfully received data, in contrast to 4- and 16-QAM. The novel results show that hierarchical modulation achieves superior performance especially in the lower ES/N0 regions.