Partially unique mappings for bit-interleaved coded modulation with iterative detection

We consider bit-interleaved coded modulation with iterative (turbo) detection and non-unique mappings of bits to QAM/PSK symbols which allow better performance in the error floor region compared to unique mappings. Ambiguities are resolved in the iterative detection process. Furthermore, we propose partially unique mappings which together with a carefully designed channel coding scheme enable a good trade-off between performance without and with turbo iterations. This makes turbo iterations optional but not mandatory. Moreover, the detection complexity and the peak to average power ratio can be reduced with non-unique mappings compared to unique-mappings with turbo detection.