In this modern era, Orthogonal Frequency Division Multiplexing (OFDM) has been proved to be an explicit promising technique for wired and wireless systems because of its several advantages like high spectral efficiency, robustness against frequency selective fading, relatively simple receiver implementation etc. Besides having a number of advantages OFDM suffers from few disadvantages like high...

Direct-detection (DD) optical fiber frequency division multiple access (FDMA) is a simple and practical alternative to optical heterodyne FDMA. Previous works on estimating the performance of DD optical FDMA networks have usually focused only on the (linear) crosstalk degradation, typically relying on simplifying approximations such as the dominance of the adjacent channel interference [1], [4]...

In this contribution we present some analytical performance bounds that point out the key parameters dominating the performance of symbol-by-symbol combined-type maximum a posteriori equalizers/decoders for trellis-coded modulation (TCM) transmissions over fast-faded intersymbol-interference-impaired Rayleigh-channels with diversity reception. Guidelines are also provided for the design of good...

The symmetric cutoff rate is derived for quadratureamplitude-modulated (QAM) block-coded data transmissions over noisy links affected by time-correlated multipathphenomena which introduce intersymbol interference (ISI) in the received signal. Maximum likelihood (ML) decoding supported by perfect channel-state information (CSI) is assumed. Due to the presence of time-correlated ISI phenomena, th...

In this letter new upper bounds for the performance of the optimum combined symbol-by-symbol (SbS) Abend–Fritchman-like equalizer and decoder are presented, and a related criterion for the actual design of good trellis-coded-modulated (TCM) schemes effectively matched to the distortion introduced by the intersymbol interference (ISI)-corrupted transmission channel is developed. The actual appli...

The effect of group-delay ripples in dispersion-managed soliton communication systems that use chirped fiber gratings for dispersion compensation is studied. Using both a reduced model and direct numerical simulation, we find that dispersion-managed solitons exist even in the presence of large dispersion variation caused by group-delay ripples. The dispersion-managed solitons suppress the growt...

A new modified version called decision feedback complex recurrent neural network equalizer (DFCRNNE) is proposed with the study of complex recurrent neural network equalizer (CRNNE). Based on DFCRNNE, a modified real time recurrent learning (CRTRL) algorithm is developed. Simulation results show that DFCRNNE has better performance than CRNNE based on traditional CRTRL algorithm2 in complex nonl...

In this paper we address sequence estimation when the InterSymbol Interference (ISI) communication channel is unknown and time varying. We employ a Maximum A Posterior (MAP) approach, in which the unknown channel parameters are assigned a distribution and integrated out. For several channel models of interest we describe both the exact MAP estimator and Viterbi algorithm based implementations. ...

In this paper, a blind sequence estimation algorithm based on interacting multiple model is introduced to estimate the channel and the transmitted sequence corrupted by ISI (intersymbol interference) and noise. The proposed algorithm avoids the exponential growth complexity caused by increasing channel memory length. The performance of the IMM (interacting multiple model) based equalizer is stu...

Digital transmission in wireless local area networks (WLANs) according to the IEEE 802.11b standard suffers from fading, intersymbol interference (ISI), and co–channel interference (CCI). In this paper, receivers with joint interference cancellation and time–reversal space–time block decoding (JICSTD) are proposed for an enhanced version of the IEEE 802.11b WLAN standard with space–time coded t...