1,721,106 research outputs found
Some new rotationally invariant TCM schemes for multidimensional M-PSK
No full textTrellis codes for multidimensional constellations offer a number of advantages which cannot be obtained with bidimensional constellations. Some new trellis codes for multidimensional M-PSK constellations are presented. They are all completely rotationally invariant. The performance of these codes is discussed and compared with that exhibited by Ungerboeck codes for bidimensional phase modulation with the same effective rate
A per-survivor phase-estimation algorithm for detection of PSK signals
No full textIn this letter, an expectation-maximization (EM) technique for maximum a posteriori (MAP) estimation of a random parameter is employed to devise a per-survivor phase-tracking algorithm for phase-shift-keyed signals transmitted over channels with phase jitter. Simulation results show that the proposed algorithm can provide substantial performance gains over recursive and non-recursive phase estimators in the presence of a strong phase jitter
GQR-based reduced models for multipath Rayleigh fading channels
No full textIn this paper reduced complexity statistical models for the representation of wide sense stationary-uncorrelated scattering (WSS-US) doubly-selective fading channels are developed. Their derivation is based on the evaluation of Fourier integrals by means of Gaussian quadrature rules (GQRs). The accuracy and the complexity of the proposed models are assessed and are compared with that provided by other modelling techniques available in the literature
Performance analysis of matched and partially matched one-shot detectors over doubly-selective Rayleigh fading channels
No full textIn this paper optimum one-shot detection over known and partially known doubly-selective Rayleigh fading channels is investigated. The performance analysis of the detection algorithms is based on GQR (Gauss quadrature rules) and power series channel models. The proposed methods allow to assess the implicit diversity gain provided by both channel multipath and signal fading and the energy loss due to the mismatch of the receiver filter
A Bayesian Demand-Side Management Strategy for Smart Micro-Grid
No full textIn this manuscript a novel strategy for distributed and autonomous demand-side energy management among users of a low-voltage micro-grid is developed. Its derivation is based on: a) modelling the energy consumption scheduling of the shiftable loads that belong to a given user as a noncooperative two-player game of incomplete information, in which the user itself plays against an opponent collecting all the other users of the same micro-grid; b) assuming that each user is endowed with statistical information about its behavior and that of its opponent, so that it can choose actions maximising its expected utility. Numerical results evidence the efficacy of the proposed strategy when employed to manage the charging of electric vehicles in a micro-grid
GQR models for multipath Rayleigh fading channels
No full textIn this paper, reduced complexity statistical models for the representation of wide sense stationary-uncorrelated scattering doubly selective fading channels are developed. Their derivation is based on the evaluation of Fourier integrals by means of Gaussian quadrature rules. The accuracy and the complexity of the proposed models is assessed, and is then compared to that provided by other modeling techniques available in the literature
Further results on differential space-time modulations
No full textIn this paper, some novel results on the space-time differential modulation schemes described by Hochwald and Sweldens, and Tarokh and Jafarkhani, are derived under the assumption of a quasi-static multiple-antenna channel. First, the optimality (in the maximum-likelihood sense) of the one-shot detection algorithms of Hochwald and Sweldens, and Throkh and Jafarkhani, is proved. Then the expression of the pairwise error probability for these detectors is derived, and, as a particular case, the bit-error rate is computed for the binary phase-shift keyed scheme of Throkh and Jafarkhani. Finally, a per-survivor processing (PSP) detection algorithm for this class of modulations is illustrated. Numerical results evidence both the superiority of the PSP strategy over the one-shot space-time differential detectors and the accuracy of the above-mentioned bit-error rate formula
Performance analysis of OFDM signalling over doubly-selective fading channels
No full textA simple method for the evaluation of the error rate performance of OFDM signals transmitted over doubly-selective fading channels is described. The accuracy of the proposed technique is exemplified by simulation results. Power series models for multipath channels are employed to derive simple expressions for the average signal-to-interference ratio (SIR) and the average error probability
Further results on Tarokh's space-time differential technique
No full textNovel results on the space-time differential detection technique described by V. Tarokh and H. Jafarkhani (see IEEE J. Select. Areas Commun., vol.18, no.7, p.1169-74, 2000) are derived. First, the optimality of the one-shot detection algorithm proposed by Tarokh and Jafarkhani is proved under some assumptions about the channel model and an accurate bit error rate formula for this detector is derived in a particular case. Finally, a per-survivor processing (PSP) receiver, substantially outperforming Tarokh's detector, is derived. Numerical results show both the superiority of the PSP receiver over the one-shot detector and the accuracy of the above mentioned error rate formula
Frequency-domain equalization for space-time block-coded systems
No full textIn this paper, conventional and turbo-channel-equalization algorithms processing two samples of the received signal per channel symbol and operating in the frequency domain are proposed for space-time block-coded systems. In the class of conventional equalization techniques, minimum-mean-square-error (MAISE) linear and decision-feedback equalizers (DFE) are derived and a synthesis technique based on the well-known Levinson-Durbin algorithm is proposed for the latter. Similarly, iterative linear and decision-feedback-equalization algorithms for turbo receivers are devised. Performance results show the efficacy of the proposed equalization techniques and their superiority over other frequency-domain-equalization strategies
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