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.

Transmission rate control method and mobile station

Abstract: A transmission rate control method for controlling a transmission rate of user data transmitted by a mobile station via a logical channel, include: notifying, at a radio network controller, a guaranteed bit rate of the logical channel to the mobile station; and controlling, at the mobile station, a transmission rate of uplink user data to be transmitted via the logical channel without following a command in a relative rate grant channel received from a cell to which the mobile station connects.

Parallel key-insulated public key encryption

Abstract: Security is constantly been infringed by inadvertent loss of secret keys, and as a solution, Dodis, Katz, Xu, and Yung [11], in Eurocrypt 2002, proposed a new paradigm called key-insulated security which provides tolerance against key exposures. Their scheme introduces a “helper key” which is used to periodically update the decryption key. The most attractive part of this scheme is that even if a decryption key of a time period is exposed, the security of the rest of the periods are unaffected. But how does this helper key managed? Can it be done efficiently? As, to alleviate the damage caused by key exposures, decryption key has to be updated at very short intervals, although frequent updating will, in contrary, increase the risk of helper key exposure. In this paper, we propose parallel key-insulated public key encryption in which two distinct helper keys alternately update a decryption key. The helper key of one system is independent from the other. Not only does it decrease the chance of helper key exposures, it also allows frequent updating of the decryption key, and over all, increases the security of the system.

Transmitting apparatus, receiving apparatus, mobile communication system, and transmission control method

Abstract: A transmitting apparatus comprises a switching means for switching wireless access methods; a frequency domain signal generating means for assigning a wireless resource to a spread chip sequence, which has been subjected to one of a fast Fourier transform process and a serial/parallel conversion process in accordance with a wireless access method as switched, to generate a frequency domain signal; and a transport signal generating means for performing an inverse fast Fourier transform of the frequency domain signal to generate a transport signal.

Mobile communication system, transmission station, reception station, relay station, communication path deciding method, and communication path deciding program

Abstract: A mobile communication system capable of deciding a communication path that can realize a multihop high-speed communication. A mobile communication system (1), which comprises a mobile station (10), one or more relay stations (30) and a base station (20), performs a packet transmission from the mobile station (10) to the base station (20) via one or more relay stations (30) or via no relay stations. The mobile communication system (1) has a communication path deciding part for deciding, based on the interference levels of the signals received by the base station (20) and by the relay stations (30) constituting the communication paths between the transmission and reception stations, a communication path that exhibits the highest communication speed or a communication path that satisfies a required line quality.

Method and system for server load balancing

Abstract: In one aspect of the invention, a method for load balancing a plurality of servers is provided. The method comprises intercepting a request from a requestor client forming part of a client group for a service provided by the plurality of servers, determining wait times for servicing prior requests from at least one member client of the client group by at least one of the plurality of servers, and selecting an execution server from among the plurality of servers for responding to the request dynamically based on a computation of the wait times.