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.

Mobile communication method

Abstract: In a mobile communication method according to the present invention includes the steps of: transmitting, from a handover source radio base station to a swithcing center, a handover request including an NCC, a PCI and a K eNB *; changing, at the swithcing center, the NCC, changing, at the swithcing center, the K eNB * on the basis of the PCI, and transmitting, from the swithcing center to the handover target radio base station, the handover request including the changed NCC and the changed K eNB *; generating, at the handover target radio base station, a first key on the basis of the K eNB *; and generating, at the mobile station, the first key on the basis of the NCC and the PCI included in a handover command.

Wireless network handoff key

Abstract: The present invention provides a method and system for handoff in a wireless communication network. In one embodiment, a common handoff encryption key is generated by an authentication server and transmitted to a first access point and a second access point. The first access point transmits the handoff encryption key to a wireless terminal. The wireless terminal encrypts output data with the handoff encryption key. When the wireless terminal is associated with the second access point, the second access point decrypts data from the wireless terminal with the handoff encryption key. In a second embodiment, a handoff WEP key generation secret parameter is provided to a first and a second access point. Both access points generate a handoff WEP key as a function of the handoff WEP key generation secret parameter and an address of a wireless terminal. The first access point transmits the handoff WEP key to the wireless terminal. The second access point communicates data packets encrypted with the handoff WEP key with the wireless terminal.

System for end user monitoring of network service conditions across heterogeneous networks

Abstract: A network monitoring system for monitoring network performance across heterogeneous networks with an end device is disclosed. The network monitoring system includes a network comprising a first heterogeneous network communicatively coupled with a second heterogeneous network. The first heterogeneous network may include the end device, an intermediate node and a gateway. The second heterogeneous network may include an application server. The end device and the application server may communicate over the network with a datastream. The end device may generate a tracer packet as part of the datastream. The datastream may travel through the intermediate node. The intermediate node may store network service information in the tracer packet. The gateway may operate as an interface to the second heterogeneous network. The gateway may intercept the tracer packet and store network condition information therein. In addition, the gateway may redirect the tracer packet back to the end device over the first heterogeneous network. The end device may process the information contained in the tracer packet to determine current network and application server operating conditions, and provide results of the processing to a user of the end device.

A new control plane for 5G network architecture with a case study on unified handoff, mobility, and routing management

Abstract: The tremendous growth in wireless Internet use is showing no signs of slowing down. Existing cellular networks are starting to be insufficient in meeting this demand, in part due to their inflexible and expensive equipment as well as complex and non-agile control plane. Software-defined networking is emerging as a natural solution for next generation cellular networks as it enables further network function virtualization opportunities and network programmability. In this article, we advocate an all-SDN network architecture with hierarchical network control capabilities to allow for different grades of performance and complexity in offering core network services and provide service differentiation for 5G systems. As a showcase of this architecture, we introduce a unified approach to mobility, handoff, and routing management and offer connectivity management as a service (CMaaS). CMaaS is offered to application developers and over-the-top service providers to provide a range of options in protecting their flows against subscriber mobility at different price levels.

Error characteristics and calibration-free techniques for wireless LAN-based location estimation

Abstract: Using wireless LAN technology for location estimation provides alternate means to enable location-based applications without investment in sensor network infrastructure and special hardware. However, the main drawback of wireless LAN-based location systems is calibration of signal strength as a function of location in spatially high-density, which consumes manual labor and needs to be carried out repeatedly. In this paper, we analyze empirical error characteristics of calibration-based location algorithms such as triangulation in various spatial densities of calibration, using commercially available wireless LAN products. Then, we propose Triangular Interpolation and eXtrapolation (TIX), a calibration-free location algorithm, and present empirical performance evaluation. TIX can achieve mean distance error within 5.4 m, which is comparable to within 4.7 m errors of the calibration-based algorithms. We also present theoretical analysis on error characteristics of the location algorithms deriving accuracy limits and quantifying the effect of RF measurement and calibration.