Widely linear FRESH receiver for SAIC/MAIC with frequency offsets

International audienceWidely linear (WL) receivers are able to fulfill single antenna interference cancellation (SAIC) of one rectilinear (R) (ASK, BPSK) or quasi-rectilinear (QR) (MSK, GMSK, OQAM) co-channel interference (CCI), a function which is operational in GSM handsets in particular. However, in most cases, SAIC technology loses its efficiency if the residual frequency offset (FO) of the CCI is above a very small fraction of the baud rate. It may be the case for airborne communications, due to high differential Doppler shifts. It may also be the case if we try to use SAIC/MAIC receivers to mitigate intrinsic inter-carrier interference (ICI) of FBMC-OQAM waveforms, which are candidate for 5G networks, and for which the ICI FO is equal to 50% of the (real) baud rate. In this context, the purpose of this paper is twofold. The first one is to extend, for an arbitrary propagation channel and from a MLSE-based approach, the SAIC/MAIC concept to R or QR signals with differential FO using WL FRESH filtering. The second one is to analyse both analytically and by simulations the impact of the residual CCI FO on the performance of the proposed SAIC/MAIC receive

Reception filter impact on widely linear FRESH receiver performance for SAIC/MAIC with frequency offsets

International audienceWidely linear (WL) receivers are able to fulfill single antenna interference cancellation (SAIC) of one rectilinear (R) (ASK, BPSK) or quasi-rectilinear (QR) (MSK, GMSK, OQAM) co-channel interference (CCI). In the presence of residual frequency offsets (FO), standard SAIC/MAIC receivers lose their efficiency and have to be extended using WL frequency shifted (FRESH) filtering, which has been done recently. However, in practice the observations are low-pass filtered before sampling and processing, which may degrade the performance. In this context, the purpose of the paper is twofold. The first one is to extend the previous pseudo MLSE-based WL FRESH receiver, for sources with differential FO, to observations which are low-pass filtered. The second one is to analyze, both analytically and by simulations, the impact of the low-pass filtering on the performance of the extended pseudo MLSE-based WL FRESH receive