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.

Apparatus and method for controlling an operation of a plurality of communication layers in a layered communication scenario

Abstract: An Apparatus for controlling an operation of a plurality of communication layers of a layered communication system, the layered communication system transmitting information through a communication channel, comprises means for providing a property of the communication channel, an extractor for extracting a first set of parameters of a first communication layer and a second set of parameters of a second communication layer to determine current statuses of the first and second communication layer, means for providing a first abstraction model and a second abstraction model, wherein the first abstraction model models a characteristic of the first communication layer, and wherein the second abstraction model models a characteristic of the second communication layer, means for determining an optimized first set of parameters to be used by the first communication layer and an optimized second set of parameters to be used by the second communication layer based on the first abstraction model, the second abstraction model, the channel property and an optimization goal, means for providing the optimized first set of parameters to the first communication layer and the optimized second set of parameters to the second communication layer. Therefore, an efficient exploitation of communication resources can be achieved.

Mobile communication systems

Abstract: A mobile communication system includes a base station connected to a backbone network, and a mobile station configured to communicate with the base station using a radio frequency. The system has a first communication mode, in which a first radio frequency is used for an uplink and a second radio frequency is used for a downlink; a second communication mode, in which the first radio frequency is used for the uplink, and the second radio frequency is shared by the uplink and the downlink; a third communication mode, in which the second radio frequency is used for the downlink, and the first radio frequency is shared by the uplink and the downlink; and a mode switcher configured to switch the first through third communication modes in accordance with data transfer volumes on the uplink and the downlink.

Improved Component Carrier Selection Method for Non-Continuous Carrier Aggregation in LTE-Advanced Systems

Abstract: In order to meet the requirement of wider bandwidth in IMT-Advanced, carrier aggregation (CA) is introduced by 3GPP to support bandwidth up to 100MHz in its LTE-Advanced standards. An LTE Rel.10 UE can aggregate up to 5 component carriers (CCs) simultaneously, but may be assigned only part of the total available CCs depending on its capability or traffic load. Thus, a proper CC selection method is necessary. First, two traditional CC selection methods respectively named Random and Round Robin CC selection are investigated, which can well balance the load across different CCs. However, neither of them is suitable for non-continuous CA scenarios through our analysis. To solve this problem, an improved CC selection method for non-continuous CA is proposed in this paper. Simulation results demonstrate that the proposed method outperforms both of the traditional ones.

Controller apparatus, mobile terminal, and communication control method

Abstract: A controller apparatus of this invention controls transmission of a packet from a source mobile terminal to a destination mobile terminal through one or more relay mobile terminals in an ad hoc network formed by a plurality of mobile terminals. The controller apparatus includes a packet location information managing unit configured to manage packet location information which shows to which mobile terminal the packet has been transmitted in the ad hoc network.

Mobile communication system, base station apparatus, user apparatus and method

Abstract: A communication apparatus in a mobile communication system includes a first control information generation unit configured to generate first control information including retransmission information on a previously received data channel, a second control information generation unit configured to generate second control information including scheduling information on radio resources and a transmission signal generation unit configured to generate a transmission signal including a lower layer control channel including at least one of the first control information and the second control information. The transmission signal generation unit generates the transmission signal to transmit the first control information in any of subframes arriving at a first cycle and to transmit the second control information in any of subframes arriving at a second cycle longer than the first cycle.