An approach to performance enhancement of non-coherent equaliser receivers

High bit rate cordless transmission systems (e.g., DECT and emerging radio LANs) tend to use simple non-coherent receivers, and their performance can be constrained by channel dispersion. Equalisation can be used (supplementing other techniques such as diversity), but requires high frequency stability. In this contribution we use the DECT system as a case study and introduce a robust non-coherent receiver which performs equalisation at the output of a differential detector. The limitations of this basic structure are overcome by using a second, complementary differential processor. Simple algorithms are utilised to switch between the basic and complementary structures. The performance assessment of the new receiver is presented. The results suggest that the receiver achieves a significant extension of the dispersive channel operation range for DECT (maximum tolerable delay spreads of around 460-500 ns) with a multipath diversity gain comparable to a coherent equaliser receiver. On the other hand, unlike coherent structures, it remains largely unaffected by both frequency offsets and modulation index drifts