New insights into optimal widely linear array receivers for the demodulation of BPSK, MSK, and GMSK signals corrupted by noncircular interferences-application to SAIC

Performance Limits of Alphabet Diversities for FIR SISO Channel Identification

“…We see from this figure that the AMV bound outperforms by far the LS/SS algorithm, and the latter is outperformed in a large domain of α by the C(k, q) formula of Giannakis 8 . Next, we note that these algorithms require very large data samples for an effective estimation (here T = 100000).…”

“…This is one of the reasons why HOS-based techniques are still often preferred. Other more recent techniques incorporate the knowledge of the symbol constellation, which eventually amounts to using noncircularity of the symbol sequence [4], [5], [6], [7], [8]. It is thus legitimate to ask oneself the question whether the latter are more attractive than HOS-based approaches.…”

Complex‐Valued Adaptive Signal Processing

“…However many signals are not stationary, and a good number of complex-valued signals such as fMRI and wind data as shown in Section 1.2.5, do not necessarily have circular distributions. Thus, the importance of widely linear filters started to be noted and widely linear filters have been proposed for applications such as interference cancelation, demodulation, and equalization for direct sequence code-division-multiple-access systems and array receivers [23,56,99] implemented either in direct form, or computed adaptively using the least-mean-square (LMS) [99] or recursive least squares (RLS) algorithms [55]. Next, we present the widely linear mean-square error filter and discuss its properties, in particular when computed using LMS updates as discussed in [5].…”

“…It can be shown that the performance of the two filters can be equal even for cases where the input is highly noncircular (see Problems 1.6 and 1.7). However, when certain circularity properties do not hold, widely linear filters provide important advantages in terms of performance [23,94,101] by including the complete statistical information.…”

Efficient receivers for GSM MUROS downlink transmission

“…To this end, single antenna interference cancellation (SAIC) algorithms have been developed, e.g. [3]- [9], exploiting the special properties of the GMSK modulation which can be well approximated by filtered binary phase-shift keying (BPSK) modulation. SAIC algorithms are highly beneficial especially for downlink transmission because only a single receive antenna is required for interference suppression; at the mobile station, most often no antenna diversity is incorporated.…”