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.

Distributed wireless access method based on network allocation vector (NAV) table and apparatus of the same

Abstract: Embodiments of the present invention include a wireless access method based on a NAVT (Network allocation vector table), which is applied to a distributed wireless mobile communication system comprising a plurality of nodes, the NAVT comprises a packet type field and a duration field and is stored in the respective nodes of the communication system, comprising: on a transmitting side, determining whether only a RTS (request to send) item is contained in the NAVT when a packet arrives; sensing channel to judge whether the channel is busy after determining that only the RTS item is contained in the NAVT; sending a RTS packet based on the RTS item to the receiving side after determining that the channel is busy; and on a receiving side, determining whether the NAVT is empty or not when the RTS packet is received; sending a CTS (clear to send) packet back to the transmitting side after determining that the NAVT is empty.

Multiuser MIMO downlink with limited inter-cell cooperation: Approximate interference alignment in time, frequency and space

Abstract: We consider a realistic albeit simplified scenario for wireless cellular systems of the next generation (4G and beyond), where MIMO-OFDM, opportunistic scheduling, channel state information at the transmitter and limited base-station cooperation are envisaged. We propose two strategies with limited base-station cooperation that can be easily implemented with today's technology and achieve an approximate form of inter-cell interference alignment. The first strategy consists of imposing a ldquopower maskrdquo in frequency such that adjacent cooperative clusters of base stations generate different interference levels in different frequency subchannels. The second strategy consists of switching between different cooperative clusters such that no user is in a permanently disadvantaged location.We compare single-user and multiuser MIMO systems in terms of average throughput as a function of the user location.

User device and base station

Abstract: This disclosure pertains to a technology for reducing the flashlight effect in 3D MIMO. One mode of this invention pertains to a user device that has the following: a transmission/reception unit that receives an interfering-beam-candidate list containing directional beams transmitted by a serving base station and interfering-beam candidates transmitted by a neighboring base station; a measurement unit that measures the received quality levels of reference signals transmitted via the respective directional beams in the received interfering-beam-candidate list; and an interference-information generation unit that generates interference information on the basis of the measured received quality levels. The transmission/reception unit sends the generated interference information to the serving base station or the neighboring base station.

"Unvoiced speech recognition using EMG - mime speech recognition"

Abstract: We propose unvoiced speech recognition, "Mime Speech Recognition" It recognizes speech by observing the muscles associated with speech It is not based on voice signals but electromyography (EMG) It will realize unvoiced communication, which is a new communication style Because voice signals are not used, it can be applied in noisy environments; it also supports people without vocal-cords and aphasics In preliminary experiments, we try to recognize the 5 Japanese vowels EMG signals from the 3 muscles that contribute greatly to the utterance of Japanese vowels are input to a neural network The recognition accuracy is over 90% for the three subjects tested

Motion Compensated Prediction and Interpolation Filter Design in H.265/HEVC

Abstract: Coding efficiency gains in the new High Efficiency Video Coding (H.265/HEVC) video coding standard are achieved by improving many aspects of the traditional hybrid coding framework. Motion compensated prediction, and in particular the interpolation filter, is one area that was improved significantly over H.264/AVC. This paper presents the details of the interpolation filter design of the H.265/HEVC standard. First, the improvements of H.265/HEVC interpolation filtering over H.264/AVC are presented. These improvements include novel filter coefficient design with an increased number of taps and utilizing higher precision operations in interpolation filter computations. Then, the computational complexity is analyzed, both from theoretical and practical perspectives. Theoretical complexity analysis is done by studying the worst-case complexity analytically, whereas practical analysis is done by profiling an optimized decoder implementation. Coding efficiency improvements over the H.264/AVC interpolation filter are studied and experimental results are presented. They show a 4.0% average bitrate reduction for the luma component and 11.3% average bitrate reduction for the chroma components. The coding efficiency gains are significant for some video sequences and can reach up to 21.7%.