Results 21 to 30 of about 1,252,380 (279)
Is the spatially averaged spectrum equal to the global spectrum? [PDF]
physica status solidi (c), 2003 Near-field optical spectroscopy and microscopy give access to excitations that cannot be revealed in the far zone. In order to investigate these remarkable differences, we present a theoretical analysis of the local optical properties of semiconductor quantum wells including the effects of disorder arising from interface fluctuations.
G. PISTONE +3 more
openaire +2 more sources
Radar spectrum opportunities for cognitive communications transmission [PDF]
, 2008 In relation to opportunistic access to radar spectrum, the impact of the radar on a communication system is investigated in this paper. This paper illustrates that by exploring the spatial and temporal opportunities in the radar spectrum and therefore ...
Doufexi, A +3 more
core +3 more sources
Error Self-calibration Method in Spatial Spectrum Estimation
Leida xuebao, 2014 An important bottleneck in spatial spectrum estimation theory is array errors. A new error self-calibration method is presented on the basis of active error calibration and online self-calibration theories.
Huang Chuan-lu, Chao Kun, Mao Yun-zhi
doaj +1 more source
Spatial spectrum approach for pilot spoofing attack detection in MIMO systems
ETRI Journal, 2021 In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink–downlink channel reciprocity in time‐division‐duplex multiple‐input multiple‐output systems.
Lina Ning +4 more
doaj +1 more source
Spatial Spectrum Analysis of Wave-Front Correction with a Segmented Mirror [PDF]
, 2003 An expression is derived for the spatial power spectrum of wave-front errors after correction with a segmented mirror. This includes estimates of the spectral contributions of segment piston and tilt corrections and spatial aliasing by a regular array of
Padin, Stephen
core +1 more source
Quantum Structure of Space Near a Black Hole Horizon [PDF]
, 2006 We describe a midi-superspace quantization scheme for generic single horizon black holes in which only the spatial diffeomorphisms are fixed. The remaining Hamiltonian constraint yields an infinite set of decoupled eigenvalue equations: one at each ...
Ashtekar A +12 more
core +2 more sources
The Coupled Cluster Method in Hamiltonian Lattice Field Theory: SU(2) Glueballs [PDF]
, 2001 The glueball spectrum within the Hamiltonian formulation of lattice gauge theory (without fermions) is calculated for the gauge group SU(2) and for two spatial dimensions.
A.C. Irving +23 more
core +2 more sources
Peak to average power ratio based spatial spectrum sensing for cognitive radio systems [PDF]
, 2017 The recent convergence of wireless standards for incorporation of spatial dimension in wireless systems has made spatial spectrum sensing based on Peak to Average Power Ratio (PAPR) of the received signal, a promising approach.
Ghafoor, Abdul +2 more
core +1 more source
Joint Multidimensional Pattern for Spectrum Prediction Using GNN
Sensors, 2023 In general, judging the use/idle state of the wireless spectrum is the foundation for cognitive radio users (secondary users, SUs) to access limited spectrum resources efficiently.
Xiaomin Wen +3 more
doaj +1 more source
Spatial spectrum and energy efficiency of random cellular networks [PDF]
, 2015 It is a great challenge to evaluate the network performance of cellular mobile communication systems. In this paper, we propose new spatial spectrum and energy efficiency models for Poisson-Voronoi tessellation (PVT) random cellular networks. To evaluate
Ge, Xiaohu +5 more
core +2 more sources