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.

Content providing method, providing facility, and user facility

Abstract: In a duplication/distribution center (DDS), in response to requests of contents providing devices (CP11 and CP12), contents (C11 and C12) are recorded and duplicated on a recording medium (M) and are distributed to a user. The contents are partially encrypted. The contents providing devices (CP11 and CP12) request a content control device (CC1) to control the contents on the recording medium (M). When the user of the contents uses the contents which are encrypted by loading the recording medium (M) in a TV game machine (GM), the TV game machine (GM) requests the content control device (CC1) to transmit a decoding key through a mobile packet communication network (MPN). The content control device (CC1) determines whether or not the decoding key is to be transmitted, on the basis of the content of the request from the content providing device.

Method and apparatus for setting active period starting point for user equipment

Abstract: The present invention has disclosed a method for setting an active period starting point for a User Equipment (UE) in a Discontinuous Reception (DRX) mode, comprising steps of: a base station calculating and storing a position of the active period starting point for the UE based on predetermined parameters, so as to transmit data to the UE in a corresponding active period; the UE receiving Radio Resource Control (RRC) configuration information from the base station, and detecting whether the DRX mode is configured in it or not; the UE calculating its active period starting point based on predetermined DRX parameters in the received RRC configuration information; and the UE starting DRX based on the calculated active period starting point. The present invention has also disclosed an apparatus for setting an active period starting point for a UE in a DRX mode.

A framework for context-aware handover decisions

Abstract: Traditionally, handover decisions are made mainly based on the signal strength. However, with the evolution of mobile networks moving toward a heterogeneous solution, this simple decision mechanism is not enough any more. To choose the optimal access router among the multitude points of attachment available to the network, there is a need for a more intelligent handover decision mechanism. In this paper we provide a general framework for handover decisions which take into account the context of both the mobile network and the user. Our solution shows how to collect the context, to compile information, and to propagate it proactively. Due to the fast evolving nature of context information, our flexible framework allows one to update the decision algorithm and the context data. We present the architecture and the main components of our proposed implementation based on active networks.

Pseudo-Inverse MMSE Based QRD-M Algorithm for MIMO OFDM

Abstract: We propose a pseudo-inverse minimum mean squared error (MMSE) based QR decomposition (QRD) M-algorithm (QRD-M) for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. The proposed algorithm can effectively mitigate the detrimental effect of MIMO channel ill-conditions on the bit error rate (BER) performance. As a result, the number of retained branches (M value) can be reduced to half of the original QRD-M algorithm in Kyeong Jin Kim and R.A. Iltis (2002) in order to achieve the same performance for both the uncoded and coded systems. The detection complexity is therefore greatly reduced

Base station, mobile station, and method

Abstract: A single carrier scheme is used in an uplink in the mobile communication system. A base station used in the mobile communication system includes: means configured to perform communication with a mobile station that uses the whole or a part of a system frequency band; storage means configured to store correspondence relationship between radio parameters including a bandwidth, a modulation scheme and a channel coding rate of the uplink and filter parameters including at least a roll-off factor of a band limitation filter; and determination means configured to determine radio parameters and filter parameters for each mobile station based on the correspondence relationship according to channel state of the uplink. The radio parameters and the filter parameters determined in the determination means are reported to the mobile station.