4,311 research outputs found

    Full-Duplex Cloud Radio Access Network: Stochastic Design and Analysis

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    Full-duplex (FD) has emerged as a disruptive communications paradigm for enhancing the achievable spectral efficiency (SE), thanks to the recent major breakthroughs in self-interference (SI) mitigation. The FD versus half-duplex (HD) SE gain, in cellular networks, is however largely limited by the mutual-interference (MI) between the downlink (DL) and the uplink (UL). A potential remedy for tackling the MI bottleneck is through cooperative communications. This paper provides a stochastic design and analysis of FD enabled cloud radio access network (C-RAN) under the Poisson point process (PPP)-based abstraction model of multi-antenna radio units (RUs) and user equipments (UEs). We consider different disjoint and user-centric approaches towards the formation of finite clusters in the C-RAN. Contrary to most existing studies, we explicitly take into consideration non-isotropic fading channel conditions and finite-capacity fronthaul links. Accordingly, upper-bound expressions for the C-RAN DL and UL SEs, involving the statistics of all intended and interfering signals, are derived. The performance of the FD C-RAN is investigated through the proposed theoretical framework and Monte-Carlo (MC) simulations. The results indicate that significant FD versus HD C-RAN SE gains can be achieved, particularly in the presence of sufficient-capacity fronthaul links and advanced interference cancellation capabilities

    QCD radiative correction to color-octet J/ψJ/\psi inclusive production at B Factories

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    In nonrelativistic Quantum Chromodynamics (NRQCD), we study the next-to-leading order (NLO) QCD radiative correction to the color-octet J/ψJ/\psi inclusive production at B Factories. Compared with the leading-order (LO) result, the NLO QCD corrections are found to enhance the short-distance coefficients in the color-octet J/ψJ/\psi production e+e−→ccˉ(3P0(8)or3P0(8))g e^+ e^-\to c \bar c (^3P_0^{(8)} {\rm or} ^3P_0^{(8)})g by a factor of about 1.9. Moreover, the peak at the endpoint in the J/ψJ/\psi energy distribution predicted at LO can be smeared by the NLO corrections, but the major color-octet contribution still comes from the large energy region of J/ψJ/\psi. By fitting the latest data of σ(e+e−→J/ψ+Xnon−ccˉ)\sigma(e^{+}e^{-}\to J/\psi+X_{\mathrm{non-c\bar{c}}}) observed by Belle, we find that the values of color-octet matrix elements are much smaller than expected earlier by using the naive velocity scaling rules or extracted from fitting experimental data with LO calculations. As the most stringent constraint by setting the color-singlet contribution to be zero in e+e−→J/ψ+Xnon−ccˉe^{+}e^{-}\to J/\psi+X_{\mathrm{non-c\bar{c}}}, we get an upper limit of the color-octet matrix element, +4.0<0∣OJ/ψ[3P0(8)]∣0>/mc2<(2.0±0.6)×10−2GeV3 + 4.0 <0| {\cal O}^{J/\psi} [{}^3P_0^{(8)}]|0>/m_c^2 <(2.0 \pm 0.6)\times 10^{-2} {\rm GeV}^3 at NLO in αs\alpha_s.Comment: 18 pages, 8 figure

    Based on Regular Expression Matching of Evaluation of the Task Performance in WSN: A Queue Theory Approach

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    Due to the limited resources of wireless sensor network, low efficiency of real-time communication scheduling, poor safety defects, and so forth, a queuing performance evaluation approach based on regular expression match is proposed, which is a method that consists of matching preprocessing phase, validation phase, and queuing model of performance evaluation phase. Firstly, the subset of related sequence is generated in preprocessing phase, guiding the validation phase distributed matching. Secondly, in the validation phase, the subset of features clustering, the compressed matching table is more convenient for distributed parallel matching. Finally, based on the queuing model, the sensor networks of task scheduling dynamic performance are evaluated. Experiments show that our approach ensures accurate matching and computational efficiency of more than 70%; it not only effectively detects data packets and access control, but also uses queuing method to determine the parameters of task scheduling in wireless sensor networks. The method for medium scale or large scale distributed wireless node has a good applicability

    Braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in patients with unruptured complex intracranial aneurysms

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    &nbsp; Purposes: Braided and laser-cut stents both are efficacious and safe for coiling intracranial aneurysms. The study aimed to compare outcomes following braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in&nbsp;266&nbsp;patients who were diagnosed with unruptured intracranial aneurysms of different types and locations. Methods: Patients with unruptured complex intracranial aneurysms underwent braided (BSE cohort, n&nbsp;=&nbsp;125) or laser engraved (LSE cohort, n&nbsp;=&nbsp;141) stent-assisted embolization. Results: The deployment success rate was higher for patients of the LSE cohort than those of the BSE cohort (140&nbsp;[99%] vs. 117&nbsp;[94%], p&nbsp;=&nbsp;0.0142). Seventy-one (fifty-seven percentages) and 73&nbsp;(52%) were coil embolization procedure success rates of the BSE and the LSE cohorts. Periprocedural intracranial hemorrhage was higher in patients of the BSE cohort than those of the LSE cohort (8&nbsp;[6%]&nbsp;vs.&nbsp;1&nbsp;[1%], p&nbsp;=&nbsp;0.0142). Four (three percentages) patients from the LSE cohort and 3&nbsp;(2%) patients from the BSE cohort had in-stent thrombosis during embolization. Permanent morbidities were higher in patients of the LSE cohort than those of the BSE cohort (8&nbsp;[6%]&nbsp;vs.&nbsp;1&nbsp;[1%], p&nbsp;=&nbsp;0.0389). Higher successful procedures (76% vs.&nbsp;68%) and fewer postprocedural intracranial hemorrhage (0% vs.&nbsp;5%) and mortality (0% vs.&nbsp;5%) were reported for patients of the BSE cohort in posterior circulation aneurysmal location than those of the LSE cohort. Laser engraved stent has fewer problems with deployment and may have better periprocedural and follow-up outcomes after embolization. Conclusions: Braided stent-assisted embolization should be preferred when the aneurysm is present in the posterior circulation
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