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Institution

NTT DoCoMo

About: NTT DoCoMo is a based out in . It is known for research contribution in the topics: Base station & Mobile station. The organization has 4032 authors who have published 8655 publications receiving 160533 citations.


Papers
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Patent
21 Feb 2002
TL;DR: In this paper, a user inputs desired mobile ID number to a client terminal and transmits a request for location information on the mobile station including the mobile ID numbers to a location server via a location information server.
Abstract: In an information providing system, a user inputs desired mobile ID number to a client terminal. The client terminal transmits a request for location information on the mobile station including the mobile ID number to a location server via a location information server. The location server transmits a request for object movement information corresponding to the mobile station to an object information server. The location information server obtains the information from a traffic control device. Location information on the mobile station obtained by the location information server is transmitted to the terminal.

87 citations

Patent
17 Dec 1999
TL;DR: In this article, a high sensitivity receiver installed outdoors which may be used in a base station of a mobile communication system was described, where a received radio frequency signal was converted into a signal in a desired frequency band by a reception bandpass filter RXF3, subject to low noise amplification to a desired level by a low noise reception amplifier LNA4, and the amplified signal is converted into an optical signal by a laser diode LD5.
Abstract: The invention relates to a high sensitivity receiver installed outdoors which may be used in a base station of a mobile communication system, for example. A received radio frequency signal is converted into a signal in a desired frequency band by a reception bandpass filter RXF3, is subject to a low noise amplification to a desired level by a low noise reception amplifier LNA4, and the amplified signal is converted into an optical signal by a laser diode LD5. RXF3, LNA4 and LD5 are confined in a heat shielding box. LD5 is cooled by cooling means to the order of critical temperature where RXF3, for example, assumes a superconducting state, whereby the dynamic range is increased and stabilized.

87 citations

Patent
17 Oct 2003
TL;DR: In this paper, a mobile station 1 is camped on cell C10 established by base station B10, and there exist indoor cells C11-C13 and outdoor cells C21, C22 as neighboring cells.
Abstract: In mobile communication system 100 according to the present invention, mobile station 1 is camped on cell C10 established by base station B10. In the cell C10, there exist indoor cells C11-C13 and outdoor cells C21, C22 as neighboring cells. Mobile station 1 measures received levels of cells C10-C13, C21, C22 and determines cell types of the respective cells, i.e., whether each cell is an indoor cell or not, based on broadcast information M1. Mobile station 1 selects a cell as a reselection target on the basis of the received levels and cell types.

87 citations

Journal ArticleDOI
TL;DR: An overview of the Release 13 LAA technology including motivation, use cases, LTE enhancements for enabling the unlicensed band operation, and the coexistence evaluation results contributed by 3GPP participants is provided.
Abstract: Exploiting the unlicensed spectrum is considered by 3GPP as one promising solution to meet ever-increasing traffic growth. As a result, one major enhancement for LTE in Release 13 has been to enable its operation in the unlicensed spectrum via licensed-assisted access (LAA). In this article, we provide an overview of the Release 13 LAA technology including motivation, use cases, LTE enhancements for enabling the unlicensed band operation, and the coexistence evaluation results contributed by 3GPP participants.

86 citations

Patent
26 Jun 2009
TL;DR: In this paper, a distributed certificate authority includes a CA and a number of Sub-CAs (2610), each of which has secret certificate validation data, but different data are provided to different Sub-CA for each certificate.
Abstract: Different targets (c0, N1) of a digital certificate are mapped into a 'super-target' using methods allowing a certificate validity verifier (110) to compute the super-target. The certificate includes the super-target instead of the targets. Also, a certificate with multiple targets can be signed with a redactable signature by the certification authority (CA 120). When the certificate's owner provides the certificate to a verifier together with a validity proof, the owner redacts the certificate to delete unnecessary targets. A single validity proof (ci(F)) may be provided to certificate owners for a set (F) of the certificates via a multicast transmission if a multicasting group (2010) is formed to correspond to the set. A verifier (110) may decide to cache the validity proof for a set provide the cached proof to other parties. The caching decision is based on the caching priority of the set F. The priority may depend on the number of certificates in the set F, the sum of the remaining validity periods for the certificates in the set, and other factors. In the setup phase, the CA generates validation proof data structures for greater time than the maximum validity period of any certificate. Therefore, new certificates can be added to the existing data structures after the setup phase. A distributed certificate authority includes a CA and a number of Sub-CAs (2610). The Sub-CAs have secret certificate validation data, but different data are provided to different Sub-CAs for each certificate. If a Sub-CA is compromised, the Sub-CA validity proof will be withheld by the CA to alert the verifiers not to use the data from this Sub-CA. Also, the secret data are encrypted when distributed to the Sub-CAs. A decryption key (DK.j.k) for each 'partition' of time is distributed to each Sub-CA at or shortly before the start of the partition. A compromised Sub-CA can be reactivated at the end of the partition because the adversary does not get the decryption keys for the future partitions.

86 citations


Authors

Showing all 4032 results

NameH-indexPapersCitations
Amit P. Sheth10175342655
Harald Haas8575034927
Giuseppe Caire8282540344
Craig Gentry7522239327
Raj Jain6442430018
Karl Aberer6355417392
Fumiyuki Adachi54101015344
Ismail Guvenc5245113893
Frank Piessens5239110381
Wolfgang Kellerer495029383
Yoshihisa Kishiyama4837911831
Ravi Jain481607467
Josef A. Nossek4862310377
Tadao Nagatsuma4743011117
Christian Bettstetter4620411051
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202164
2020143
2019240
2018269
2017193
2016173