Widely linear decision-feedback equalizer for time-dispersive linear MIMO channels

Abstract

The paper deals with the transmission over multiple-input/multiple-output channels exhibiting time-dispersion. A minimum mean-square error equalizer based on widely linear processing combined with the decision-feedback (DF) strategy is implemented via finite-impulse-response filters. The proposed equalizer provides considerable performance gain at the expense of a limited increase in computational complexity. The performance analysis has been carried out accounting for mismatch conditions always present in practice. The results confirm the stronger sensitivity of the DF-based equalizers with respect to the feedforward-based ones when system parameters are not accurately known

A new family of optimized orthogonal Space-Times codes for PPM-based MIMO systems with imperfect channel estimates

“…Therefore, since for the OPPM-based STBCs here considered, the eigenvalue d 2 min is limited up to two [see the upper bound in (21)], whereas δ 2 max is (obviously) lower bounded by zero see Eq. 22, we conclude that the d 2 min and δ 2 max eigenvalues of the unitary OPPM-based STBCs, attaining the maximum coding gain, must equate…”

“…Furthermore, in any case, MIMO precoders demand for (very) reliable feedback links to communicate back to the transmitter the path-gains estimates available at the receiver. On the other hand, especially when blind equalization is attempted, MIMO DFEs may be affected by error-propagation phenomena that may (drastically) reduce the coding/diversity gain offered by the employed STBCs see, for example, [21] and references therein for recent contributions on this topic). In principle, the transceiver scheme, proposed in [3] for multipath-impaired SISO systems promises to investigate the above mentioned drawbacks, suffered by MIMO precoders and DFEs.…”

MIMO Detection Schemes with Interference and Noise Estimation Enhancement

“…For example, an MMSE equalizer and a decision-feedback equalizer (DFE) employing WLP and implemented via finite impulse response (FIR) filters for a MIMO frequency selective channel have been proposed in [21] and [22], respectively. It was concluded that the use of WLP yields considerable performance improvements at the cost of only a limited increase in complexity compared to conventional linear processing.…”

A Novel Multistage Equalization Algorithm

“…proposed in [6], [7]. It was concluded that the use of WLP yields considerable performance improvements at the cost of only a limited increase in complexity compared to conventional linear processing.…”