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.

Energy-aware resource allocation for device-to-device underlay communication

Abstract: Device-to-device (D2D) communication as an underlay to cellular networks brings significant benefits to users' throughput and battery lifetime. The allocation of power and channel resources to D2D communication needs elaborate coordination, as D2D user equipments (UEs) cause interference to other UEs. In this paper, we propose a novel resource allocation scheme to improve the performance of D2D communication. Battery lifetime is explicitly considered as our optimization goal. We first formulate the allocation problem as a non-cooperative resource allocation game in which D2D UEs are viewed as players competing for channel resources. Then, we add pricing to the game in order to improve the efficacy, and propose an efficient auction algorithm. We also perform simulations to prove efficacy of the proposed algorithm.

Range Expansion and Inter-Cell Interference Coordination (ICIC) for Picocell Networks

Abstract: Range expansion (RE), when applied with inter-cell interference coordination (ICIC) may have significant benefits for improving the throughput and fairness of macrocell/picocell networks. In this paper, first, benefits of RE in the uplink and downlink are reviewed, emphasizing its definitive merit for uplink communications. It is shown that while RE also improves the fairness in the downlink, it may seriously degrade the total system capacity if no ICIC is utilized. Then, a novel cell-selection technique that capitalizes on subframe-blanking at the macrocell is introduced for improving the downlink capacity and fairness. System level simulation results show that the proposed cellselection method adaptively achieves a good balance between sum capacity and fairness, and can be used in place of biasbased cell-selection.

System for managing program applications storable in a mobile terminal

Abstract: Management server 16 may obtain application programs from content server 20 in response to requests of mobile terminal 11. Management server 16 may transmit the obtained application programs to mobile terminal 11 with information concerning reliabilities of the application programs. After mobile terminal 11 receives the application programs from management server 16, mobile terminal 11 manages operations of the application programs. Operations of the application programs are coordinated with operations of other programs using the information concerning the reliabilities corresponding to the application programs. Management of the coordinated operations of the application programs avoids problems concerning information security, where valuable information may be distributed unexpectedly because of operations of low reliable application programs. As a result, convenience of users of mobile terminals 11 can be improved without deteriorating the information security of mobile terminals 11.

Mobile station and radio base station

Abstract: A mobile station UE is provided with an access right management unit for managing a CSG-ID corresponding to a CSG cell which permits the mobile station UE to access thereto, a measurement unit for measuring the radio quality of a CSG cell defined as an object to be measured, and a measurement report transmission unit for, only when the radio quality of a CSG cell corresponding to the CSG-ID managed by the access right management unit out of the radio qualities of CSG cells measured by the measurement unit satisfies a report condition, transmitting a measurement report including at least the radio quality of the CSG cell corresponding to the CSG-ID.

Cyclic delay diversity with bit-interleaved coded modulation in orthogonal frequency division multiple access

Abstract: We consider cyclic delay diversity in OFDMA. Cyclic delay diversity is an elegant way to obtain spatial diversity in an FEC coded OFDM system without exceeding the guard interval. We first address the problem of choosing the cyclic delays and propose a new robust design rule which enables to pick up the full spatial and frequency diversity which is inherent in a frequency-selective MIMO channel. Our choice of cyclic delays has consequences for the interleaving and multiple access scheme since the spatial diversity appears to be transformed into frequency diversity between neighbouring subcarriers. Therefore, a system with a conventional block frequency interleaver will fail to exploit the spatial diversity. We propose an interleaving and multiple access strategy which guarantees that all users obtain the maximum possible diversity advantage using FEC codes with a limited constraint length. Furthermore, we provide a performance comparison to transmit diversity from orthogonal designs