Abstract:
Disclosed is a method enabling the improvement of the multisensor reception of a system of radiocommunications exchanging signals between at least one fixed base station providing for multisensor reception by means of a network of sensors, and the processing of the signals. This method consists, in a transparent manner perceived from the base station, in computing a weighting vector W for the formation of channels at reception. The weighting vector W is estimated by an adaptive algorithm leading to a maximization of the signal-to-noise ratio. Application: mobile radiocommunications. FIG. 1
Abstract:
The method consists in estimating the matrix of correlation R.sub.XX of the signals received on a set of N reception sensors, computing the reverse correlation matrix R.sub.XX.sup.-n, computing vectors of intercorrelation r.sub.Xd between the signals received on the set of the N sensors and a known replica signal d(k), computing a criterion of synchronization in calculating the products of the conjugate, transposed intercorrection vectors R.sub.XX.sup.-n and of the matrix of the intercorrelation vector r.sub.Xdi and comparing the value of the criterion obtained with a determined threshold value 1 to place the synchronization on the sample for which the value of the criteria exceeds the threshold value .eta.. To estimate the Doppler shift the synchronization sequence is subdivided into a determined number of sections of symbols to carry out fast Fourier transform computations on determined intercorrelation vectors in each section.
Abstract translation:该方法在于估计在一组N个接收传感器上接收到的信号的相关值E,cir R + EE XX矩阵,计算反向相关矩阵+ E,cir R + EE XX-n,互相关的计算向量+ E,cir r + EE Xd在所述N个传感器的组合上接收的信号和已知复制信号d(k)之间,计算共轭的乘积的计算准则,转置的互补向量+ E,cir R + EE XX-n和互相关向量rXdi的矩阵,并且将获得的准则的值与确定的阈值1进行比较,以将该准则置于样本上,其中标准值超过阈值eta。 为了估计多普勒频移,同步序列被细分为确定数量的符号段,以便在每个部分中确定的相互相关矢量上执行快速傅里叶变换计算。
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.