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.

Multiple-antenna techniques in LTE-advanced

Abstract: In this article we discuss the different multiple antenna techniques introduced in LTE-Advanced. Rather than describing the technical details of the adopted solutions, we approach the problem starting from the design targets and the antenna deployments prioritized by the operators. Then we present the main enabling solutions introduced for downlink and uplink transmissions, and subsequently assess the performance of these solutions in different scenarios. Finally, we discuss some possible future developments.

Method for supporting scalable and reliable multicast in tdma/tdd systems using feedback suppression techniques

Abstract: A method supports scalable and reliable multicast in a wireless network with a large bandwidth-delay product. In this method, acknowledgement packets from different receivers experiencing the same number of data packets lost are assigned the same time slots. This method can be combined with other loss recovery techniques, such as forward error correction (FEC) recovery, proactive protection, feedback suppression and collision detection. Scalability is achieved as bandwidth usage relates only to the number of packets transmitted, rather than the number of receivers.

Context-aware market-making service

Abstract: A mobile virtual network operators system is disclosed. The mobile virtual network operators system provides a single point of contact for wireless customers accessing a variety of services offered by a plurality of vendors. The mobile virtual network operators system may generate a sales proposal for a customer or a vendor and handle a proposal generated by a customer or a vendor. The mobile virtual network operators system may include a vendor database and a customer database. The mobile virtual network operators system receives, records and analyzes plurality of the customer's product search requests to form the customer's context aware purchase history. The customer database may store accumulated context aware purchase histories for a plurality of customers. The mobile virtual network operators system may generate a solicitation proposal for a customer based on the customer's context aware purchase history. The mobile virtual network operators system can anticipate customer's needs in advance and can generate a proposal accordingly.

Information processing device and program

Abstract: The present invention provides an information processing device for estimating usage of contents and properly limiting functions realized through use of the contents in accordance with the estimation. Usage of contents is estimated by determining in which of cache memory means and content storage means the contents are stored. When the contents are processed or executed, it is determined whether to limit functions realized through processing or execution of the contents, on the basis of the estimated usage of the contents and function limit information showing a rule regarding limits on functions realized through processing or execution. On the basis of the determination, the functions realized through processing or execution of the contents are limited.

Broadband packet wireless access appropriate for high-speed and high-capacity throughput

Abstract: This paper evaluates the optimum broadband packet wireless access scheme using a 50-100 MHz bandwidth to achieve highspeed packet transmission taking into consideration the realization of high-speed and high-capacity packet transmission, the accommodation of variable rate services with different quality requirements, and the extendibility for and commonality to the IMT-2000. In the forward link, the presented simulation results associated with the evaluation of key features show that multi-carrier CDMA (MC-CDMA) is the most promising candidate, since it achieves the highest-capacity packet transmission in a severe multipath fading channel due to a lower symbol-rate with numerous sub-carriers and a channel coding gain accompanied by the frequency diversity effect. Meanwhile, single-carrier/DS-CDMA and multi-carrier/DS-CDMA (SC/DS-CDMA and MC/DS-CDMA) are severely degraded due to significantly increasing multipath interference, and orthogonal frequency division multiplexing (OFDM) lacks efficient cell deployment due to the necessity of frequency reuse in a multi-cell environment without complicated dynamic channel assignment (DCA). Furthermore, in the reverse link, we conclude that MC(SC)/DS-CDMA is a promising candidate because it has advantages such as an effective random access method, soft handover, and an inherent property for accurate location detection.