1,721,141 research outputs found
Asymptotic performance of FBMC-PAM systems in frequency-selective Rayleigh fading channels
No full textWindowed OFDM for small-cell 5G uplink
No full textWe consider one of the most interesting candidates for the 5G transceiver system, the windowed OFDM, and we carry out an evaluation of the spectral efficiency that can be achieved in the uplink of small but crowded cells by means of a time-frequency multiple-access scheme. Our analysis is first carried out in the absence of multiple-access interference in order to determine a performance upper bound and to gain more insights about the role of the system parameters. The main contribution of the paper is constituted by the evaluation of the achievable spectral efficiency as a function of the most important transceiver parameters, and above all by the number of subcarriers assigned to each active mobile terminal. In particular, we show that, unlike the downlink scenario, the spectral efficiency in multiple access is not optimized by choosing the cyclic prefix length to be just larger than the multipath delay spread, but increasing it much more, especially when the number of adjacent subcarriers assigned to each terminal is small
Analisi nel dominio del tempo della turbolenza nel campo di moto di un getto a simmetria assiale
No full textUse of numerical modeling to identify the transfer function and application to the geostatistical procedure in the solution of inverse problems in groundwater
No full textThe restoring of the pollutant release history makes use of transfer functions
(TFs) usually known by analytical formulation. In many cases the computation
of an analytical TF is not possible; this fact limits the application of the inverse procedures
to very simple conditions or it forces to drastic simplifications of complicated
problems. In this paper a new procedure, useful to compute the numerical transfer
functions in transport problems with no analytical solution, is outlined. This method,
analogous to the computation of the Instantaneous Unit Hydrograph (IUH) in surface
hydrology, makes use of mathematical modelling
On the performance of FBMC-PAM systems in frequency-selective Rayleigh fading channels
No full textFilter bank multicarrier (FBMC) techniques are emerging alternatives to the widely used orthogonal frequency division multiplexing (OFDM) schemes for applications such as machine type communications or cognitive radio. Recently an FBMC scheme based on a sine prototype filter with overlapping factor K=2 termed FBMC-PAM has been introduced. It assures an interesting performance, a reduced system latency and is robust to carrier-frequency offset. After presentation of the system model, an analytical expression of the BER of the single-tap sub-channel equalizer for the considered FBMC-PAM system operating in frequency-selective Rayleigh fading channel is obtained and compared with simulation results. Moreover, a performance comparison with an approximate single-tap sub-channel equalizer and with the previously proposed FBMC-PAM-2M, is presented
Comparing the performance of OFDM and FBMC multicarrier systems in doubly-dispersive wireless channels
No full textIn mobile communications, the most widely used multicarrier technique, namely OFDM, is known to exhibit performance limitations in high speed scenarios. FBMC is an alternative approach and, among FBMC techniques, the recently introduced FBMC-PAM scheme has emerged as the most robust to CFO. Therefore, it is chosen here as the challenger of OFDM for performance comparison in doubly dispersive channels. After presentation of the system model, multicarrier scheme and wireless channel, an analytical evaluation of the BER in the particular case of single path time-varying channel is provided for FBMC-PAM and validated through simulations. Then, simulation results are reported for both OFDM and FBMC-PAM, using the 3GPP multipath channel models. It appears that FBMC-PAM can outperform OFDM in highly time-varying frequency-selective channels
Performance of a square-law combiner for reception of Nakagami fading orthogonal signals in Spherically invariant noise
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