In this paper, we experimentally demonstrate a 450-nm laser underwater optical wireless transmission system, in which comprehensive investigation is made to show the significant performance improvement of discrete Fourier transform spread multi-tone (DFT-S DMT) as compared conventional quadrature amplitude modulation (QAM-DMT) modulation. DFT-S DMT outperforms QAM-DMT terms bit error rate (BER)...

Abstract. One-step iterative decoding for bit-interleaved coded QAM with conventional Gray mapping can give a significant improvement of performance for fading channels. Furthermore, iterative decoding with ideally known feed back bits is easier to analyze theoretically than non-iterative decoding. In this paper, we derive analytical expressions for the pairwise error probabilities for bit-inte...

Multiple-Input Multiple-Output (MIMO) systems as a means to combat fading in wireless channels. MIMO allows higher throughput, diversity gain and interference reduction. In this paper, we analyze the Bit Error Rate (BER) performance of the Alamouti Space Time Block Code with V-BLAST (Vertical Bell Laboratories Layered Space-Time) over MIMO system. Basic idea in this scheme is to improve the BER...

Free space optical (FSO) communication link is a line of sight (LOS) wireless link between the nodes separated by an unguided medium such that visible and infrared bands of the spectrum are used as data carrier. Recent past has witnessed huge revival of research interest in this field so as to make FSO commercially viable and looking into this prospective, data modulation techniques are one of ...

This paper presents the estimation of bit error ratio (BER) from error vector magnitude (EVM) for M-ary quadrature amplitude modulation (QAM) formats in optical coherent systems employing carrier phase recovery with differential decoding to compensate for laser phase noise. Simulation results show that the relationship to estimate BER from EVM analysis for data-aided reception can also be appli...

The impact of the fiber Kerr effect on error statistics in the nonlinear (high power) transmission of the OFDM 16-QAM signal over a 2000 km EDFA-based link is examined. We observed and quantified the difference in the error statistics for constellation points located at three power-defined rings. Theoretical analysis of a trade-off between redundancy and error rate reduction using probabilistic...

It is well-known that constant-modulus-based algorithms present a large mean-square error for high-order quadrature amplitude modulation (QAM) signals, which may damage the switching to decision-directed-based algorithms. In this paper, we introduce a regional multimodulus algorithm for blind equalization of QAM signals that performs similarly to the supervised normalized least-mean-squares (NL...

In this demonstration, we propose and demonstrate an adaptive long-reach passive optical network (LR-PON) using four-band orthogonal frequency division multiplexed (OFDM) channels. The downstream traffic rates from 6.25 to 40 Gb/s (using fixed quadrature amplitude modulation (QAM) level in the four OFDM bands) and from 9.37 to 40.3 Gb/s (using variable QAM levels in the four OFDM bands) can be ...

The paper analyzes the BER and spectral efficiency performances of convolutionally-coded square QAM constellations that map non-coded bits, besides the coded ones, in an OFDM environment that imposes a user bin with only 81 QAM payloadsymbols. It shows that the QAM constellations that map only coded bits using coding rates higher than 2/3 are outperformed , i.e. higher coding gains and/or soect...

In this paper, we propose algorithms for signal detection in large-scale multiuser spatial modulation multipleinput multiple-output (SM-MIMO) systems. In large-scale SMMIMO, each user is equipped with multiple transmit antennas (e.g., 2 or 4 antennas) but only one transmit RF chain, and the base station (BS) is equipped with tens to hundreds of (e.g., 128) receive antennas. In SM-MIMO, in a giv...