NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

Compact semiconductor device capable of mounting a plurality of semiconductor chips with high density and method of manufacturing the same

Abstract: In a semiconductor device, rewirings 3 for connecting a semiconductor chip 1 a , a semiconductor chip 1 b and external connecting terminals 4 with each other are formed on the semiconductor chip 1 a An insulating resin 6 having opening portions in regions for forming the external connecting terminals 4 at peripheral portion of the semiconductor chip 1 a and another opening portions in another region for mounting the semiconductor chip 1 b at the central of the semiconductor chip 1 a is overlaid on the rewirings 3 The external connecting terminals 4 consisting of BGA are formed in the opening portions of the regions for forming the external connecting terminals 4 through lands 5 The semiconductor chip 1 b is connected to another opening portions of another region for mounting the semiconductor chip 1 b by flip-chip structure through electrodes 11 and bumps 8 A junction surface of the bumps 8 is sealed by a sealing resin 7 The semiconductor chip 1 b is mounted on the same surface as that the external connecting terminals 4 are formed The under surface of the semiconductor chip 1 b is ground in order that the semiconductor chip 1 b may be shorter than the external connecting terminals 4 The semiconductor chip 1 b is thereby mounted with high density

De-interleaver, mobile communication terminal, and de-interleaving method

Abstract: A de-interleaver has a TTI frame buffer storing a TTI frame before de-interleaving, a P bit information table storing P bit information containing the size and added position of P bits to be added to the TTI frame before de-interleaving, and a permutation rule table storing permutation rules of de-interleaving. The de-interleaver performs de-interleaving on the data stored in the TTI frame buffer based on the P bit information stored in the P bit information table and the permutation rules stored in the permutation rule table.

Software-defined control of the virtualized mobile packet core

Abstract: Mobile packet core networks are undergoing major changes to meet the requirements of the future data tsunami, enhance network flexibility, and reduce both CAPEX and OPEX. In this regard, SDN and NFV technologies have gained great momentum among the teleos, with the promise of interoperability, programmability, and on-demand dynamic provisioning. In this article, we present work being developed in the Mobile Packet Core project within the ONF Wireless & Mobile Working Group regarding SDN architecture for the Mobile Packet Core. In addition, we propose an SDN-based MPC in the NFV context in order to facilitate dynamic provisioning of MPC network functions. Finally, a potential control architecture considering both SDN and NFV is proposed.

SAT-based image computation with application in reachability analysis

Abstract: Image computation finds wide application in VLSI CAD, such as state reachability analysis in formal verification and synthesis, combinational verification, combinational and sequential test. Existing BDD-based symbolic algorithms for image computation are limited by memory resources in practice, while SAT-based algorithms that can obtain the image by enumerating satisfying assignments to a CNF representation of the Boolean relation are potentially limited by time resources. We propose new algorithms that combine BDDs and SAT in order to exploit their complementary benefits, and to offer a mechanism for trading off space vs. time. In particular, (1) our integrated algorithm uses BDDs to represent the input and image sets, and a CNF formula to represent the Boolean relation, (2) a fundamental enhancement called BDD Bounding is used whereby the SAT solver uses the BDDs for the input set and the dynamically changing image set to prune the search space of all solutions, (3) BDDs are used to compute all solutions below intermediate points in the SAT decision tree, (4) a fine-grained variable quantification schedule is used for each BDD subproblem, based on the CNF representation of the Boolean relation. These enhancements coupled with more engineering heuristics lead to an overall algorithm that can potentially handle larger problems. This is supported by our preliminary results on exact reachability analysis of ISCAS benchmark circuits.

Time-modulated electron cyclotron resonance plasma discharge for controlling generation of reactive species

Abstract: This study examines modulated electron cyclotron resonance (ECR) plasma discharge occurring within a few tens of μs. It can control the generation of reactive species in plasmas. Reactive species are measured by an actinometric optical emission spectroscopy in the pulsed plasma. Good correlation is found between the density ratio of CF2 radicals and F atoms in the CHF3 plasma, and the combination of the pulse duration and pulse intervals. These characteristics are explained by the dependence of reactive species generation in ECR plasma on a time within a few tens of μs. This method provides for controlling the polymerization during SiO2 etching.