1,867 research outputs found
Indoor gigabit optical wireless communications: challenges and possibilities
Indoor Gigabit optical wireless communication systems have the potential to offer multiple high-speed data services that can be delivered to homes via an optical fibre cable in the near future. In this paper we will discuss the challenges involved in the design of such systems and future possible advances. Results from a recent cellular Gigabit prototype link will also be presented and discussed
PDA-BCJR algorithm for factorial hidden Markov models with application to MIMO equalisation
Publication in the conference proceedings of EUSIPCO, Florence, Italy, 200
Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications
To increase system capacity of underwater optical communications, we employ
the spatial domain to simultaneously transmit multiple orthogonal spatial
beams, each carrying an independent data channel. In this paper, we multiplex
and transmit four green orbital angular momentum (OAM) beams through a single
aperture. Moreover, we investigate the degrading effects of
scattering/turbidity, water current, and thermal gradient-induced turbulence,
and we find that thermal gradients cause the most distortions and turbidity
causes the most loss. We show systems results using two different data
generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for
1-Gbit/s/beam, we use both techniques since present data-modulation
technologies are faster for infrared (IR) than for green. For the higher-rate
link, data is modulated in the IR, and OAM imprinting is performed in the green
using a specially-designed metasurface phase mask. For the lower rates, a green
laser diode is directly modulated. Finally, we show that inter-channel
crosstalk induced by thermal gradients can be mitigated using multi-channel
equalisation processing.Comment: 26 pages, 5 figure
A computationally efficient multi-mode equaliser based on reconfigurable frequency domain processing
Symmetric Radial Basis Function Assisted Space-Time Equalisation for Multiple Receive-Antenna Aided Systems
This constribution considers nonlinear space-time equalisation (STE) designed for single-input multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of achieving the optimal Bayesian equalisation performance. The adaptive adjustment of the STE taps of this symmetric RBF (SRBF) based STE can be achieved by estimating the SIMO channel encountered using the classic least mean square channel estimator and computing the optimal RBF centres from the resultant SIMO channel matrix estimate. Our simulation results demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the algorithmic parameters
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