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.

Identity-Based aggregate signatures

Abstract: An aggregate signature is a single short string that convinces any verifier that, for all 1 ≤ i ≤ n, signer Si signed message Mi, where the n signers and n messages may all be distinct. The main motivation of aggregate signatures is compactness. However, while the aggregate signature itself may be compact, aggregate signature verification might require potentially lengthy additional information – namely, the (at most) n distinct signer public keys and the (at most) n distinct messages being signed. If the verifier must obtain and/or store this additional information, the primary benefit of aggregate signatures is largely negated. This paper initiates a line of research whose ultimate objective is to find a signature scheme in which the total information needed to verify is minimized. In particular, the verification information should preferably be as close as possible to the theoretical minimum: the complexity of describing which signer(s) signed what message(s). We move toward this objective by developing identity-based aggregate signature schemes. In our schemes, the verifier does not need to obtain and/or store various signer public keys to verify; instead, the verifier only needs a description of who signed what, along with two constant-length “tags”: the short aggregate signature and the single public key of a Private Key Generator. Our scheme is secure in the random oracle model under the computational Diffie-Hellman assumption over pairing-friendly groups against an adversary that chooses its messages and its target identities adaptively.

DCT-based image watermarking using subsampling

Abstract: A DCT-based image watermarking algorithm is described, where the original image is not required for watermark recovery, and is achieved by inserting the watermark in subimages obtained through subsampling.

User terminal, wireless base station, and wireless communication method

Abstract: In order that a user terminal properly identifies a connection cell in a radio communication system (LTE-U) for operating LTE in an unlicensed band, a user terminal for communicating with a radio base station in an unlicensed band is provided with a detection section that detects a synchronization signal transmitted from a radio base station using a dummy cell ID used in common among a plurality of radio base stations, an estimation section that performs channel estimation using a reference signal, and a reception processing section that performs reception processing of system information transmitted from a radio base station using a channel estimation result.

Layout of platform specific graphical user interface widgets migrated between heterogeneous device platforms

Abstract: A scaleable graphical user interface system utilizes a device platform independent model to provide dynamic layout of graphical user interface widgets migrated between any of a plurality of heterogeneous device platforms. The device platform independent model includes at least one platform independent graphical user interface widget. Based on the device platform independent model, platform specific graphical user interface widgets that correspond to each of the platform independent graphical user interface widgets may be laid out on a page and compared to the size of a display screen of a heterogeneous device platform. Where the page does not fit within the display screen, the platform independent graphical user interface widgets may be dynamically rearranged within the page to fit the display screen. In addition, where designated as splitable, the platform independent graphical user interface widgets may be split among multiple pages of a presentation to fit within the display screen.

Ambient networks: an architecture for communication networks beyond 3G

Abstract: In this article we present a new networking concept referred to as ambient networks, which aims to enable the cooperation of heterogeneous networks belonging to different operator or technology domains. We aim to provide a domain-structured edge-to-edge view for the network control to embrace the heterogeneity arising from the different network control technologies. In this way, it appears as homogeneous to the users of the network services. We aim for an instant network composition to allow rapid adaptation of the network domain topology as required for moving networks. This new view of network composition allows us to treat the communication endpoints as a special case of network domains as well. We introduce the ambient control space, which enables the ambient networks concept and introduce its main features. Two ambient control space functions, media delivery and generic link layer, are presented in more detail. AMBIENT NETWORKS: AN ARCHITECTURE FOR COMMUNICATION NETWORKS BEYOND 3G