Abstract:
Method and system for separating a plurality of users in a communication system including two transmitter antennas and N receiver antennas, said signals transmitted by said users containing symbols an, x( ) corresponding to the vector of the envelopes of the output signals of the 1 to N receiver antennas after a shaping filtering operation, characterized in that it uses a linear mean square filter extended over an observation vector {tilde over (x)}=[x(2n−1)T x(2n)T x(2n−1)H x(2n)H]T where x(2n−1) and x(2n) correspond to the (N×1) (N≧1) observations at the symbol times 2n−1 and 2n.
Abstract:
Method and system for separating a plurality of users in a communication system including two transmitter antennas and N receiver antennas, said signals transmitted by said users containing symbols an, x( ) corresponding to the vector of the envelopes of the output signals of the 1 to N receiver antennas after a shaping filtering operation, characterized in that it uses a linear mean square filter extended over an observation vector {tilde over (x)}=[x(2n−1)T x(2n)T x(2n−1)H x(2n)H]T where x(2n−1) and x(2n) correspond to the (N×1) (N≧1) observations at the symbol times 2n−1 and 2n.
Abstract:
An antenna processing method for centered or potentially non-centered cyclostationary signals, comprises at least one step in which one or more nth order estimators are obtained from r-order statistics, with r=1 to n−1, and for one or more values of r, it comprises a step for the correction of the estimator by means of r-order detected cyclic frequencies. The method can be applied to the separation of the emitter sources of the signals received by using the estimator or estimators.
Abstract:
Method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C2q,x(l), whose coefficients are the circular cumulants of order 2q, Cum[xi1(t), . . . , xiq(t), xiq+1(t)*, . . . , xi2q(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.
Abstract:
A method for the fourth-order, blind identification of at least two sources in a system comprising a number of sources P and a number N or reception sensors receiving the observations, said sources having different tri-spectra. The method comprises at least the following steps: a step for the fourth-order whitening of the observations received on the reception sensors in order to orthonormalize the direction vectors of the sources in the matrices of quadricovariance of the observations used; a step for the joint diagonalizing of several whitened matrices of quadricovariance in order to identify the spatial signatures of the sources. Application to a communication network.FIG. 3 to be published.
Abstract:
A method forms a bipolar transistor in a semiconductor substrate of a first conductivity type. The method includes: forming on the substrate a single-crystal silicon-germanium layer; forming a heavily-doped single-crystal silicon layer of a second conductivity type; forming a silicon oxide layer; opening a window in the silicon oxide and silicon layers; forming on the walls of the window a silicon nitride spacer; removing the silicon-germanium layer from the bottom of the window; forming in the cavity resulting from the previous removal a heavily-doped single-crystal semiconductor layer of the second conductivity type; and forming in said window the emitter of the transistor.
Abstract:
A bipolar transistor with very high dynamic performance, usable in an integrated circuit. The bipolar transistor has a single-crystal silicon emitter region with a thickness smaller than 50 nm. The base of the bipolar transistor is made of an SiGe alloy.
Abstract:
A method of synchronizing a substantially rectilinear signal being propagated through an unknown channel, in the presence of unknown substantially rectilinear interferences, received by an array of N sensors, in which a known training sequence s(nT) is used comprising K symbols and sampled at the symbol rate T (s(nT), 0≦n≦{tilde over (K)}1), characterized in that, based on observations x((n+l/p)T) over the duration of the training sequence, where p=T/Te is an integer and Te the sampling period, a virtual observation vector X((n+l/p)T)=[x((n+l/p)T)T, x((n+l/p)T)†]T is defined, as well as a decision criterion or decision statistic taking into account the second-order non-circular nature of the interferences, by using the first and second correlation matrices of the virtual observation vector X((n+l/p)T).
Abstract:
A method for the verification of anti-jamming in a communications system comprises several sensors or adaptive antennas, comprising at least the following steps: estimating the mean power π;^y of the output of the communications system, estimating the respective power values Pu or P′u, of a station u, the antenna noise Pa or P′a, the thermal noise PT, or P′T, estimating at least one of the following ratios: J tot / S tot = ( ∑ p = 1 P P p ) / ( ∑ u = 1 U P u ) J tot / S u = ( ∑ p = 1 P P p ) / P u J u / S u = ( ∑ p = 1 P P pu ) / P u comparing at least one of the three ratios with a threshold value.
Abstract:
A novel bipolar transistor with very high dynamic performances, usable in an integrated circuit. This bipolar transistor comprises a single-crystal silicon emitter region with a thickness smaller than 50 nm. The base of the bipolar transistor is made of an SiGe alloy.