The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we address the preamble-based channel estimation problem for orthogonal frequency-division multiplexing (OFDM) systems using multiple amplify-and-forward (AF) relays. We first establish a linear minimum mean-square-error (LMMSE) channel estimator which directly estimates the overall channels from the source to the destination. Then, based on the assumption that the channel correlations...
In practical orthogonal frequency division multiplexing (OFDM) systems, some virtual subcarriers are reserved for easing the requirements on the filter. In this case, the conventional discrete Fourier transform (DFT)-based filtering in frequency-domain suffers from a spectral leakage, which results in an irreducible error floor. On the other hand, the DFT-based filtering or interpolation in time-domain...
The PAPR issue in OFDM system can be formulated to a combinational optimization problem. This paper proposes a class of approaches to reduce the PAPR value of multi-carrier/OFDM system by solving this combinational optimization problem with some improved Hopfield neural networks (HNN) . Furthermore, the general theoretical framework of PAPR reduction based on all kinds of HNN is presented as well...
This paper proposes a novel approach to reduce the PAPR value of PCC-OFDM with a new stochastic Hopfield neural network rotator (S-HNN-R) with soft feedback. By adopting new neural output function and random state disturbance, the system performance is improved greatly. Furthermore, the side information isn't needed any more compared to the traditional SLM method. From numerical experiments, it is...
This paper proposes a new approach to reduce the PAPR with a new adaptive soft feedback stochastic Hopfield neural network (S-HNN). By adopting new neural output function and random state disturbance, the PAPR performance is improved greatly. Furthermore, it can be implemented easily compared to the traditional HNN method. By parameter adjustment, the lowest PAPR can be found. So it is an effective...
This paper presents approaches of link to system mapping for OFDM/multi-carrier mobile communications systems. Mainly, the effective SINR method is highlighted, which includes EESM and MI-ESM. It is shown how the multi-state channels are integrated into a single state in system simulator with effective SINR approach and why the effective SINR can represent the characteristics of multiple sub-carrier...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.