We consider a time varying wireless fading channel, equalized by an LMS Decision Feedback equalizer (DFE). We study how well this equalizer tracks the optimal MMSEDFE (Wiener) equalizer. We model the channel by an Autoregressive (AR) process. Then the LMS equalizer and the AR process are jointly approximated by the solution of a system of ODEs (ordinary differential equations). Using these ODEs...

In this paper we propose a zero forcing (ZF) timevarying (TV) finite impulse response (FIR) equalizer for doublyselective (timeand frequency-selective) channels. We use the basis expansion model (BEM) to approximate the doubly-selective channel and to design the TV FIR equalizer. This allows us to turn a large TV problem into an equivalent small time-invariant (TIV) problem, containing only the...

In digital communication system, conventional fractionally spaced equalizer (FSE) is based on linear transversal equalizer (LTE) where the noise enhancement influences the equalization result. Since equalization can also be viewed as a classification problem, the Bayesian equalizer which is the optimal symbol-decision equalizer can achieve better performance than LTE. A novel fractionally space...

This paper proposes an exclusive equalizer alternative to existing optimum maximum likelihood (ML) equalizer that reduces bit error rate (BER) via spatial multiplexing, diversity combining and splits up each user's multiple input multiple output (MIMO) channel into parallel subchannels. Quadrature phase shift keying (QPSK) modulation is treated here for the simulation purpose. The new equalizer...

In this paper, the receivers with adaptive equalizer and turbo decoder are investigated for orthogonal frequency division multiplexing-code division multiple access (OFDM-CDMA) systems in multipath channels. The de-spreading equalizer which combines de-spreading and equalization is used to mitigate the MAI and ISI. The stochastic gradient based LMS algorithm is used as the adaptive algorithm fo...

We study the performance limits of turbo equalization when the M -BCJR algorithm is used as the soft-in soft-out equalizer. We show through analysis based on EXIT charts that the M -BCJR equalizer can provide performance very close to that of the BCJR equalizer with considerably reduced complexity. We show that the current practice of using the output of the equalizer directly as a posteriori p...

This paper is concerned with the use of complexmodulated oversampled filter bank for frequency domain equalization in single carrier systems. A novel equalizer structure consisting of a low order linear phase FIR and an all-pass filter is applied in subband-wise compensation of channel amplitude and phase distortions separately. The performance of the proposed filter bank based frequency domain...

Orthogonal frequency division multiplexing (OFDM) is one of the modulation scheme, used for high speed mobile communication. However, fast time varying multipath channels leads to loss of orthogonality of subcarriers and introduces inter carrier interference (ICI). In this study, MMSE equalizer is implemented to remove ICI. The information of Channel Impulse Response (CIR) required for equalize...

An efficient adaptation technique of the delay is introduced for accomplishing more accurate adaptive linear equalization of nonminimum phase channels. It is focused that the filter structure and adaptation procedure of the adaptive Butler-Cantoni (ABC) equalizer is very suitable to deal with a variable delay for each iteration, compared with a classical adaptive linear transversal equalizer (L...

This paper shows that the BER performance using linear equalizer for channel equalization problem is significantly dependent on delay order. To obtain optimum performance, the equalizer output should be derived from the equalizer with delay order having the best BER performance. An efficient method to evaluate the upper bound BER performance of a linear equalizer to find the optimum delay is pr...