Equalisation and iterative reception for spectrally efficient CPM in multipath environments

Abstract

Modern spectrally efficient continuous phase modulation (CPM) waveforms offer attractive properties for narrowband tactical communications operating in VHF/UHF 30-400MHz bands. These waveforms exhibit robustness to a significant amount of intersymbol interference, due to multipath propagation, when iterative receivers are used for demodulation and decoding. However, certain propagation characteristics encountered in mountainous or coastal terrains may represent exceptionally challenging multipath environments. In these scenarios, the use of simple types of channel equalisation schemes, with an iterative CPM receiver, is demonstrated to alleviate the detrimental impact of multipath propagation. The combined effect of equalisation and iterative demodulation and decoding is investigated as a method to operate under these conditions.

Joint channel and carrier frequency estimation for M-ary CPM over frequency-selective channel using PAM decomposition

“…In [3], a new optimal synchronization scheme has been developed for AWGN channels (including preamble design) has been proposed to achieve the Cramer Rao Bound. In its equalization scheme, [4] uses a Thanks to Thales Alenia Space and the CNES agency (French Space Agency) for funding method suited to AWGN channel for carrier recovery [5]. In the context of equalization, channel estimation has been studied in [6,7].…”