Non-coherent receivers are attractive for pulsed Ultra-WideBand (UWB) systems due to the implementation simplicity. However, they have to face the shortage of performance degradation. Several techniques were proposed ...Non-coherent receivers are attractive for pulsed Ultra-WideBand (UWB) systems due to the implementation simplicity. However, they have to face the shortage of performance degradation. Several techniques were proposed to alleviate the noise effect and promote the receiver performance, among which is the weighted combining of multiple integration sub-intervals. In this paper, the performance of the weighted non-coherent receiver for UWB On-Off Keying (UWB-OOK) signal in multipath channels is analyzed, in terms of bit-error-rate. In addition, a closed-form expression of the approximately near-optimal weighting coefficient set is derived, and two simple weighting coefficient sets are proposed as well. Finally, the analytic results are verified via the computer simulations, which reveal obvious performance improvements to the conventional energy detector.展开更多
Mainly due to its implementation simplicity, the non-coherent Ultra-Wide Band (UWB) receiver is attractive for lower data rate applications, which gains much attention again in recent years. In this paper, a General L...Mainly due to its implementation simplicity, the non-coherent Ultra-Wide Band (UWB) receiver is attractive for lower data rate applications, which gains much attention again in recent years. In this paper, a General Likelihood Ratio Test (GLRT) based non-coherent receiver on UWB Pulse-Position-Modulation (PPM) signal in multipath channels is derived, and a novel structure is proposed as well. Subsequently, the closed-form expressions of asymptotic error-rate performance related to the non-coherent receiver are also derived and verified.展开更多
The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously inclu...The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which leads to a kind of deformed Heisenberg-Weyl algebra. Although there is no ordinary number representation in this state-vector space, several set of orthogonal and complete state-vectors can be derived which are common eigenvectors of corresponding pairs of commuting Hermitian operators. As a simple application of this state-vector space, an explicit form of two-dimensional canonical coherent state is constructed and its properties are discussed.展开更多
In this paper, a new triangular element （Quasi-Carey element） is constructed by the idea of Specht element. It is shown that this Quasi-Carey element possesses a very special property, i.e., the consistency error is...In this paper, a new triangular element （Quasi-Carey element） is constructed by the idea of Specht element. It is shown that this Quasi-Carey element possesses a very special property, i.e., the consistency error is of order O（h^2）, one order higher than its interpolation error when the exact solution belongs to H^3（Ω）. However, the interpolation error and consistency error of Carey element are of order O（h）. It seems that the above special property has never been seen for other triangular elements for the second order problems.展开更多
Coherence is one of the most salient features of a laser beam,and laser beams which are not completely coherent,the so-called partially coherent beams,are preferred in many applications.The degrees of coherence of con...Coherence is one of the most salient features of a laser beam,and laser beams which are not completely coherent,the so-called partially coherent beams,are preferred in many applications.The degrees of coherence of conventional spatial partially coherent beams can be described by Gaussian distributions.Currently,more and more attention is being paid to partially coherent beams with prescribed degrees of coherence due to their extraordinary optical properties,such as self-focusing,self-shaping,selfsplitting,periodicity reciprocity,and super-strong reconstruction. Manipulating the structure of the degree of a partially coherent beam provides a novel way for modulating and controlling its propagation properties and is useful in beam shaping,free-space optical communications,optical trapping,optical encryption and image or information transfer through adverse inhomogeneous environments.In this paper,we present a review on the recent advances in partially coherent beams with prescribed degrees of coherence.展开更多
文摘Non-coherent receivers are attractive for pulsed Ultra-WideBand (UWB) systems due to the implementation simplicity. However, they have to face the shortage of performance degradation. Several techniques were proposed to alleviate the noise effect and promote the receiver performance, among which is the weighted combining of multiple integration sub-intervals. In this paper, the performance of the weighted non-coherent receiver for UWB On-Off Keying (UWB-OOK) signal in multipath channels is analyzed, in terms of bit-error-rate. In addition, a closed-form expression of the approximately near-optimal weighting coefficient set is derived, and two simple weighting coefficient sets are proposed as well. Finally, the analytic results are verified via the computer simulations, which reveal obvious performance improvements to the conventional energy detector.
文摘Mainly due to its implementation simplicity, the non-coherent Ultra-Wide Band (UWB) receiver is attractive for lower data rate applications, which gains much attention again in recent years. In this paper, a General Likelihood Ratio Test (GLRT) based non-coherent receiver on UWB Pulse-Position-Modulation (PPM) signal in multipath channels is derived, and a novel structure is proposed as well. Subsequently, the closed-form expressions of asymptotic error-rate performance related to the non-coherent receiver are also derived and verified.
基金The project Supported by National Natural Science Foundation of China under Grant Nos. 10375056 and 90203002
文摘The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which leads to a kind of deformed Heisenberg-Weyl algebra. Although there is no ordinary number representation in this state-vector space, several set of orthogonal and complete state-vectors can be derived which are common eigenvectors of corresponding pairs of commuting Hermitian operators. As a simple application of this state-vector space, an explicit form of two-dimensional canonical coherent state is constructed and its properties are discussed.
基金This research is supported by the National Natural Science Foundation of China under Grant No.10671184
文摘In this paper, a new triangular element （Quasi-Carey element） is constructed by the idea of Specht element. It is shown that this Quasi-Carey element possesses a very special property, i.e., the consistency error is of order O（h^2）, one order higher than its interpolation error when the exact solution belongs to H^3（Ω）. However, the interpolation error and consistency error of Carey element are of order O（h）. It seems that the above special property has never been seen for other triangular elements for the second order problems.
基金supported by the National Natural Science Fund for Distinguished Young Scholar(11525418)the National Natural Science Foundation of China(11274005&11474213)+1 种基金the Project of the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutionsthe Innovation Plan for Graduate Students in the Universities of Jiangsu Province(KYZZ16_0079)
文摘Coherence is one of the most salient features of a laser beam,and laser beams which are not completely coherent,the so-called partially coherent beams,are preferred in many applications.The degrees of coherence of conventional spatial partially coherent beams can be described by Gaussian distributions.Currently,more and more attention is being paid to partially coherent beams with prescribed degrees of coherence due to their extraordinary optical properties,such as self-focusing,self-shaping,selfsplitting,periodicity reciprocity,and super-strong reconstruction. Manipulating the structure of the degree of a partially coherent beam provides a novel way for modulating and controlling its propagation properties and is useful in beam shaping,free-space optical communications,optical trapping,optical encryption and image or information transfer through adverse inhomogeneous environments.In this paper,we present a review on the recent advances in partially coherent beams with prescribed degrees of coherence.
