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.

Base station apparatus, mobile terminal apparatus and communication control method

Abstract: This invention is directed to provision of a base station apparatus, a mobile terminal apparatus and a communication control method. The base station apparatus can appropriately allocate a resource of a response signal of retransmission in response to a signal in which a plurality of layers are space-multiplexed in an uplink, and the base station apparatus further can support the next generation mobile communication system. The base station apparatus receives, from a mobile terminal apparatus (10), a signal in which a plurality of layers are space-multiplexed in an uplink; generates an ACK/NACK of HARQ for the signal received in each layer of the uplink; and uses an offset value, which has fixedly been specified between the base station apparatus and the mobile terminal apparatus (10) for each layer of the uplink, to allocate, to PHICH resource, the ACK/NACK of HARQ of a transport block related to each layer.

Method, base station and mobile station for timeslot selection and timeslot assignment

Abstract: A timeslot selection method is provided The timeslot selection method includes the steps of: obtaining a propagation loss; receiving an occupation state and an interference amount of an uplink timeslot; obtaining a desired wave power from the propagation loss; obtaining a ratio between the desired wave power and the propagation loss for the uplink timeslot in which the occupation state is idle; and selecting the transmitting timeslot by using the ratio In addition, a timeslot assignment method in which there are a plurality of TDD boundaries each of which is a boundary between at least an uplink timeslot and at least a downlink timeslot in a frame is provided Furthermore, a timeslot assignment method is provided, in which assignment is carried out according to a service class included in a QoS request

A Parameterized Base Station Power Model

Abstract: Power models are needed to assess the power consumption of cellular base stations (BSs) on an abstract level. Currently available models are either too simplified to cover necessary aspects or overly complex. We provide a parameterized linear power model which covers the individual aspects of a BS which are relevant for a power consumption analysis, especially the transmission bandwidth and the number of radio chains. Details reflecting the underlying architecture are abstracted in favor of simplicity and applicability. We identify current power-saving techniques of cellular networks for which this model can be used. Furthermore, the parameter set of typical commercial BSs is provided and compared to the underlying complex model. The complex model is well approximated while only using a fraction of the input parameters.

Two-Server password-only authenticated key exchange

Abstract: Typical protocols for password-based authentication assume a single server which stores all the information (e.g.), the password necessary to authenticate a user. Unfortunately, an inherent limitation of this approach (assuming low-entropy passwords are used) is that the user's password is exposed if this server is ever compromised. To address this issue, a number of schemes have been proposed in which a user's password information is shared among multiple servers, and these servers cooperate in a threshold manner when the user wants to authenticate. We show here a two-server protocol for this task assuming public parameters available to everyone in the system (as well as the adversary). Ours is the first provably-secure two-server protocol for the important password-only setting (in which the user need remember only a password, and not the servers' public keys), and is the first two-server protocol (in any setting) with a proof of security in the standard model.

Media streaming with online caching and peer-to-peer forwarding

Abstract: A system, method and apparatus are disclosed herein for media streaming. In one embodiment, the system comprises one or more media servers to serve media content and a plurality of peers communicably coupled to one or more other peers of the plurality of peers and at least one of the one or more media servers to receive segments of media content, where at least one of peers allocates a set of resources for serving the segments of media content including cache memory to store the segments and media files and uplink bandwidth to send the segments of media content to the one or more peers to which the one peer is communicably coupled. The system also includes a first control server to track media content demand and the allocated resources of the plurality of peers to determine which peer should cache which segment of the media file and to return peer location information specifying the one or more peer locations from which each peer is to receive each segment of each media content requested. The control server is operable to send the location information to each peer. In one embodiment, the one control server is also operable to calculate a utility of each caching option and enforce it by sending triggers to the peers to initiate the caching at those peers.