Novel techniques for performance optimisation of DECT receivers with non-linear front-end

Previously, we introduced, the concept of an advanced DECT-type receiver based on a hybrid combination of equalisation and diversity. Such a structure is capable of coping with most hostile microcell outdoor environments. This paper considers other possible solutions which attempt to achieve a similar performance level whilst allowing a completely nonlinear front-end. We first introduce an improved clock recovery technique applicable to standard DECT receivers. When using a differential phase detector, this technique can extend the maximum delay spread range to about 140-160 ns from 80-100 ns for a standard set-up with a discriminator receiver. In addition, a new diversity scheme based on emulation of a quality-based selection diversity in a single receiver is introduced. It is shown that the performance in dispersive channels is significantly improved with respect to RSSI schemes (up to 270 ns). Flat-fading gains of over 10 dB are also observed. Finally the combination of the two techniques introduced produces excellent performance (≈350 ns delay spread range) closely approximating an ideal CRC-driven selection diversity (speed independent), but using only a single receiver chain. This structure could be a strong candidate for practical implementation, particularly in handsets for DECT PCS applications