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.

Rate and robustness control with RTP monitoring agent for mobile multimedia streaming

Abstract: We propose a of control architecture for mobile multimedia streaming in which RTP monitoring agents report QoS information to media servers. The RTP monitoring agents lie midway between wired networks and radio links, monitor RTP packets sent from media servers to mobile terminals, and report quality information to media servers so that the servers can realize network-adaptive QoS control. By analyzing the information sent from the agents, the servers can distinguish quality degradation caused by network congestion from that caused by radio link errors, and can improve service quality by controlling the transmission rate and robustness against packet loss. Simulation results show our implemented QoS control schemes that use the feedbacks from the agent and control transmission rate and robustness provide better video quality than a simple rate control mechanism.

Investigation on Cell Selection Methods Associated with Inter-cell Interference Coordination in Heterogeneous Networks for LTE-Advanced Downlink

Abstract: In LTE-Advanced, a heterogeneous network where femtocells and picocells overlaid onto macrocells is extensively discussed in addition to traditional well-planned macrocell deployment to improve further the system throughput. In heterogeneous network deployment, cell selection as well as intercell interference coordination (ICIC) is very important to improve the system and cell-edge throughput. Therefore, this paper investigates three cell selection methods associated with ICIC in heterogeneous networks in the LTE-Advanced downlink: signal-to-interference plus noise power ratio (SINR)-based cell selection, reference signal received power (RSRP)-based cell selection, and reference signal received quality (RSRQ)-based cell selection. Simulation results (4 pico eNodeBs and 25 set of user equipment are uniformly located within 1 macro eNodeB) assuming full buffer model show that the downlink cell and cell-edge user throughput levels of RSRP-based cell selection are degraded by approximately 3% and 10% compared to those of SINR-based cell selection under the condition of the maximizing the cell-edge user throughput due to the impairment of the interference level. Furthermore, it is shown that the downlink cell-edge user throughput of RSRQ-based cell selection is improved approximately 5%, although the cell throughput is degraded approximately 5% compared to that for SINR-based cell selection under the condition of the maximizing the cell-edge user throughput.

Quickly finding near-optimal storage designs

Abstract: Despite the importance of storage in enterprise computer systems, there are few adequate tools to design and configure a storage system to meet application data requirements efficiently. Storage system design involves choosing the disk arrays to use, setting the configuration options on those arrays, and determining an efficient mapping of application data onto the configured system. This is a complex process because of the multitude of disk array configuration options, and the need to take into account both capacity and potentially contending I/O performance demands when placing the data. Thus, both existing tools and administrators using rules of thumb often generate designs that are of poor quality.This article presents the Disk Array Designer (DAD), which is a tool that can be used both to guide administrators in their design decisions and to automate the design process. DAD uses a generalized best-fit bin packing heuristic with randomization and backtracking to search efficiently through the huge number of possible design choices. It makes decisions using device models that estimate storage system performance. We evaluate DAD's designs based on traces from a variety of database, filesystem, and e-mail workloads. We show that DAD can handle the difficult task of configuring midrange and high-end disk arrays, even with complex real-world workloads. We also show that DAD quickly generates near-optimal storage system designs, improving in both speed and quality over previous tools.

IMT-2000: service provider's perspective

Abstract: This article provides an overview of the important issues for the development of the next generation of wireless access systems from the service provider's perspective. The specifications for this future global wireless access system (IMT-2000) are currently being developed within the International Telecommunication Union (ITU).

Fast dynamic route establishment in wireless, mobile access digital networks using mobility prediction

Abstract: Disclosed is a method applicable to third generation, wireless, mobile access IP-based data networks supporting IETF proposed Mobile IP support standards. The method reduces the end-to-end packet latency, jitter and packet loss that occur when the communication link between a mobile node and the network is handed-off from one local agent or router to another. The method greatly reduces the time necessary to establish a new network data route between the mobile node and a correspondent node during the hand-off from one agent/router to another by predicting the mobility of the mobile node, predetermining when the hand-off will occur, and establishing the new data route in advance of the hand-off.