1,833 research outputs found
Pilot-aided ML schemes for joint beamforming and channel estimation in WCDMA systems
This paper proposes semi-blind channel estimation and interference cancellation schemes for the reception of pilot-aided signals in WCDMA systems. It is shown that the performance of classical training-based schemes is severely degraded due to the code-multiplexing (as opposed to time-multiplexing) of traffic and pilot signals. The time-dispersivity of the channel destroys the orthogonality between the traffic signal and the pilot, and consequently the traffic signal appears as a new interfering signal for the channel estimation/beamforming algorithm. In order to avoid this effect, we propose techniques that exploit both the presence of the training sequence and the structure of the traffic signal in a semi-blind fashion.Peer ReviewedPostprint (published version
Canonical Noether symmetries and commutativity properties for gauge systems
For a dynamical system defined by a singular Lagrangian, canonical Noether
symmetries are characterized in terms of their commutation relations with the
evolution operators of Lagrangian and Hamiltonian formalisms. Separate
characterizations are given in phase space, in velocity space, and through an
evolution operator that links both spaces.Comment: 22 pages; some references updated, an uncited reference deleted,
minor style change
Mol·luscs epibionts de Charonia lampas (Linnaeus, 1758) (Mollusca, Gastropoda) de la badia de Palma
Abstract not availabl
In memoriam Josep Maria Palau i Camps (1914-1996)
Abstract not availabl
La fauna endèmica Iberobalear i la seva conservació
Ibero-balearic endemic fauna and its conservation. The Iberian peninsula and the Balearic Islands constitute two outstanding territories in terms of animal biodiversity and endemic species. The continental freshwater fish, the reptiles and amphibians, and to a lesser extent birds, make up the groups of most unique vertebrates and those most renowned as threatened species. The biodiversity of Iberian invertebrates seems very high, but huge research efforts and accurate studies are necessary before their diversity can be quantified
High resolution probe of coherence in low-energy charge exchange collisions with oriented targets
The trapping lasers of a magneto-optical trap (MOT) are used to bring Rb
atoms into well defined oriented states. Coupled to recoil-ion momentum
spectroscopy (RIMS), this yields a unique MOTRIMS setup which is able to probe
scattering dynamics, including their coherence features, with unprecedented
resolution. This technique is applied to the low-energy charge exchange
processes Na+Rb() Na()+Rb. The
measurements reveal detailed features of the collisional interaction which are
employed to improve the theoretical description. All of this enables to gauge
the reliability of intuitive pictures predicting the most likely capture
transitions
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