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.

Pre-coding method for MIMO system and apparatus using the method

Abstract: A pre-coding method for a MIMO system and an apparatus using the same are described. In the method, a receiver determines a corresponding codebook from a multi-codebook including multiple codebooks according to a location of a resource block, selects a corresponding codeword index from the determined codebook and transmits the index to a transmitter; the transmitter determines the corresponding codebook from the multi-codebook including multiple codebooks according to the location of the resource block where transmission data is to be transmitted, selects a corresponding codeword from the determined codebook according to the codeword index and performs pre-coding for the transmission data with the selected codeword. The pre-coding is performed with the multi-codebook in the present invention, which increases a diversity of pre-coding matrixes, so dynamic fluctuation range of a equivalent channel is improved and thus the performance of multi-user scheduling is enhanced effectively.

Location information notifying method and location information notifying apparatus

Abstract: The present invention aims to provide a common platform for providing location information, which provision corresponds to network integration. In the present invention, a location information providing unit of a gateway server obtains from a position measuring center location information of mobile communication terminals. The location information of each mobile communication terminal may generated in different representational formats. A location information providing unit converts the obtained location information into representational formats that are capable of being handled by IP servers. Following conversion, the location information providing unit transmits the location information the IP servers.

Radio communication system and communication control method

Abstract: A radio communication system includes a user device, base stations, and a communication control device. The communication control device generates and reports, to the user device, selection information that is used to select base stations with which the user device should maintain synchronization. The user device selects, based on the selection information, base stations with which the user device should maintain synchronization. The user device reports, to the communication control device, identifiers of the selected base stations and received levels of radio waves transmitted from the base stations corresponding to the identifiers. The user device maintains synchronization with each of the selected base stations.

Router and address identification information management server

Abstract: The problems of an additional load to an AR having the function of transferring a packet, a BR functioning as a border relay device, and an address management server, a packet loss due to an unnecessary inquiry to the management server, an increasing delay of a packet transfer, etc. can be reduced. According to the address identification information for identification of the type of an address, routers determine to which type the address assigned to a given packet belongs, a terminal identification address for identification of a source terminal and a destination terminal, a packet transfer address for transfer of the packet to another router, or an address requiring no address conversion. Thus, an address conversion network connected to an external IP network can be realized, an increased load by an inquiry about an erroneous address, etc. and a packet loss and delay due to an unnecessary inquiry can be reduced.

Image prediction encoding device, image prediction decoding device, image prediction encoding method, image prediction decoding method, image prediction encoding program, and image prediction decoding program

Abstract: An object is to efficiently depress mode information for identification of a prediction method even if there are a lot of prediction methods provided as to methods of generating intra-frame prediction signals in a pixel domain. An image prediction encoding device 10 has a block dividing unit 102, an intra-frame prediction signal generation method determining unit 105, an intra-frame prediction signal generating unit 106, a subtractor 108, a transform unit 109, a quantization unit 110, and an entropy encoding unit 115; the intra-frame prediction signal generation method determining unit 105 derives an adjacent region prediction method for generation of an intra-frame prediction signal highly correlated with pixel signals of an adjacent region, using a proximate pixel group to a target region, out of a plurality of first prediction methods, and predicts a target region prediction method for target pixel signals, based on the derived adjacent region prediction method; the intra-frame prediction signal generating unit 106 generates an intra-frame prediction signal for the target region, based on the target region prediction method.