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.

New dictionary and fast atom searching method for matching pursuit representation of displaced frame difference

Abstract: Matching pursuit decomposes a signal into a linear expansion of functions selected from a redundant dictionary, isolating the signal structures that are coherent with respect to a given dictionary. In this paper we focus on the Matching Pursuit representation of the displaced frame difference (dfd). In particular, we introduce a new dictionary for matching pursuit that efficiently exploits the signal structures of the dfd. We also propose a fast strategy to find the atoms exploiting the maximum of the absolute value of the error in the motion predicted image and the convergence of the MSE with the rotation of the atoms. Results show that the fast strategy is quite robust when compared to exhaustive search techniques and it improves the results of a suboptimal search strategy based on a genetic algorithm.

Radio communication control method, base station apparatus and user apparatus

Abstract: When a first traffic type to which a predetermined pattern of radio resources are allocated periodically and a second traffic type to which available radio resources are sequentially allocated are mixed and multiplexed, the present invention improves communication quality of the first and second traffic types. In a radio communication system in which a first traffic type to which a predetermined pattern of radio resources are periodically allocated and a second traffic type to which available radio resources are sequentially allocated are mixed and multiplexed, the first traffic type to which the predetermined pattern of frequency resources are allocated at fixed intervals is user-multiplexed using CDM and the second traffic type to which resource blocks are sequentially allocated starting from those in good states is multiplexed using FDM and TDM as defined in LTE.

Time slot assigning method, signal transmission method, base station control apparatus, base station, and mobile station used in a mobile communications system

Abstract: A time slot assigning method for assigning a time slot for transmission of a signal between a base station and a mobile station in each frame is provided. The method comprises assigning a first slot group used for transmission of a down signal from the base station to the mobile station; assigning a second slot group used for transmission of an up signal from the mobile station to the base station are assigned; and arranging a third slot group immediately after the first slot group, the third slot group being used giving a priority to transmission of another down signal from the base station to the mobile station.

Mobile communications network system, mobile terminal, and paging method

Abstract: A mobile communication network system is provided in which when a radio system is selected from plural types of radio systems as a radio system for use in paging, the optimum radio system for the mobile terminal to be paged can be selected. When it is selected, traffic does not concentrate on a specific radio system, or no excess delay occurs when the mobile terminal starts communications. When the mobile communications network system performs paging as a paging notification to a mobile terminal through any one of various radio systems under a communications environment in which radio waves of various radio systems having different communication systems are used, a radio system is selected from a plurality of radio systems depending on the application used in the communications of the paging requested mobile terminal and a paging operation is performed through the selected radio system when a paging request is issued.

Transfer rate control method, transmission power control method, transmission power ratio control method, mobile communication system, mobile station, and radio base station

Abstract: The present invention relates to a transmission rate control method of controlling a transmission rate of uplink user data to be transmitted from a mobile station to a radio base station. The method includes: starting to transmit at the mobile station, the uplink user data at an initial transmission rate which is informed from a network or an initial transmission rate which has been already informed from the network; and increasing at the mobile station the transmission rate of the uplink user data, up to a predetermined transmission rate, on a basis of a increase rule of the transmission rate which is beforehand determined.