Institution
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.
Topics: Base station, Mobile station, Transmission (telecommunications), Base station identity code, Terminal (electronics)
Papers published on a yearly basis
Papers
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12 May 1995TL;DR: In this article, the average value of the received power per transmission power control period of a desired signal from the base station was measured, and the difference ΔRSSI between the current average value and that of one of the previous power control periods was detected.
Abstract: A transmission power control method of a mobile station in a CDMA (Code Division Multiple Access) system which primarily controls transmission power of the mobile station by using a closed loop control which enables high accuracy power control. When the received power at the base station of a signal from the mobile station suddenly increases owing to the state of buildings surrounding the mobile station, the transmission power of the mobile station must be quickly reduced to prevent the interference to other mobile stations. The mobile station measures an average value of the received power per transmission power control period of a desired signal from the base station, and detects the difference ΔRSSI between the current average value and that of one of the previous transmission power control periods. If ΔRSSI exceeds a reference power difference ΔPth, transmission power PT corresponding to ΔRSSI is set by using an open loop transmission power control to quickly reduce the transmission power of the mobile station. If ΔRSSI is lower than ΔPth, the transmission power PT is determined in accordance with the transmission power control bit sent from the base station.
61 citations
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01 Feb 2013TL;DR: This work studies mechanisms for RF calibration that can enable distributed high-performing large-scale MIMO operation and proposes methods for relative calibration of the APs in order to ensure TDD reciprocity while not relying on an explicitly self-calibrating RF design.
Abstract: Distributed large-scale MIMO is a promising option for coping with the projected explosion in mobile traffic. It involves multiple Access Points (APs) that are connected to a central server via wired backhaul and act as a distributed MIMO transmitter, serving multiple users via spatial precoding. As is well known, large downlink (DL) spectral efficiencies can be achieved with TDD operation, pilots sent in the uplink (UL), and DL-UL channel reciprocity. With APs made of inexpensive hardware and connected via, e.g., Ethernet, synchronization and reciprocity calibration are the main hurdle for implementing a truly distributed MU-MIMO system. This work studies mechanisms for RF calibration that can enable distributed high-performing large-scale MIMO operation. We propose methods for relative calibration of the APs in order to ensure TDD reciprocity while not relying on an explicitly self-calibrating RF design. As our analysis and simulations suggest, the proposed methods significantly outperform existing self calibration methods without requiring additional signaling overhead and can enable TDD reciprocity for calibration of non-colocated networks.
61 citations
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10 Apr 2002TL;DR: In this paper, a system and method for using subnet relations to determine paging areas, for performing authentication and association, and to activate access network interfaces in wireless communication devices in a heterogeneous access network is presented.
Abstract: A system and method for using subnet relations to determine paging areas, for performing authentication and association, and to activate access network interfaces in wireless communication devices in a heterogeneous access network. Paging areas are generated using subnet relations by determining mobility agent servers within a predetermined number of subnet relations from a last active mobility agent server. Authentication and association are also accomplished using subnet relations. Access network interfaces can also be turned on and off based on subnet relations thereby conserving battery power.
61 citations
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17 May 2004TL;DR: This work discusses the problem of choosing the cyclic delays and proposes 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.
Abstract: Cyclic delay diversity is a simple transmit diversity technique for coded OFDM systems with multiple transmit antennas. It does neither require an extended guard interval nor modifications of the standard OFDM receiver. We discuss the problem of choosing the cyclic delays and propose a solution which enables us to exploit the full spatial diversity in flat fading and. frequency-selective channels with unknown delay spread. As a result, the spatial diversity is transformed into frequency diversity between neighbouring subcarriers. This imposes certain restrictions on the channel coding and interleaving scheme. Furthermore, we address multi user aspects and 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.
61 citations
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05 Jul 2009TL;DR: This paper describes the SVEF, the first open-source framework for experimental assessment of H.264 Scalable Video coding streaming Evaluation Framework, and provides the experimental performance evaluation of an SVC cross-layer in-network scheduler in a Wireless LAN hot spot scenario.
Abstract: This paper describes the H.264 Scalable Video coding streaming Evaluation Framework (SVEF). This is the first open-source framework for experimental assessment of H.264 Scalable Video Coding (SVC) delivery over real networks. Effectively adapting of the transport of an H.264 SVC stream to time-varying, bandwidth constrained, and loss prone networks is an important research area. However, very little experimental work has been performed due to the unavailability of real-time H.264 SVC players, the limitations of existing decoding software libraries when challenged with network-imparied received SVC streams (e.g., affected by random loss of Network Abstraction Layer Units - NALUs), and the lack of solutions for SVC streaming support. SVEF overcomes these issues by developing missing components and by integrating them in a hybrid online/offline experimental framework. We believe SVEF will be of significant help to the research community interested in experimentally benchmarking their own proposed SVC adaptation approaches and delivery mechanisms. As a proof-of-concept of SVEF, we provide the experimental performance evaluation of an SVC cross-layer in-network scheduler in a Wireless LAN hot spot scenario.
61 citations
Authors
Showing all 4032 results
Name | H-index | Papers | Citations |
---|---|---|---|
Amit P. Sheth | 101 | 753 | 42655 |
Harald Haas | 85 | 750 | 34927 |
Giuseppe Caire | 82 | 825 | 40344 |
Craig Gentry | 75 | 222 | 39327 |
Raj Jain | 64 | 424 | 30018 |
Karl Aberer | 63 | 554 | 17392 |
Fumiyuki Adachi | 54 | 1010 | 15344 |
Ismail Guvenc | 52 | 451 | 13893 |
Frank Piessens | 52 | 391 | 10381 |
Wolfgang Kellerer | 49 | 502 | 9383 |
Yoshihisa Kishiyama | 48 | 379 | 11831 |
Ravi Jain | 48 | 160 | 7467 |
Josef A. Nossek | 48 | 623 | 10377 |
Tadao Nagatsuma | 47 | 430 | 11117 |
Christian Bettstetter | 46 | 204 | 11051 |