HTML5 Webook

12/64

10Integrated ICTWireless Networks Research Center The use of wireless communications in information and communication networks has grown dramatically in recent years, becoming an indispensable part of daily life. This trend has generated a need for R&D toward technologies that can further enrich life through the use of radio waves as part of a wide-ranging network environment that includes ground, marine, and space communications. The goal here is to create new value such as the next-generation mobile communications system (5G), large-capacity satellite communications, and the Internet of Things (IoT) and to achieve systems and applications that can provide users with unprecedented reliability and peace of mind. The Wireless Networks Research Cen-ter conducts comprehensive research and development centered about two research laboratories distinguished by their re-search themes with the aim of expanding the field of wireless communications. The following research on wireless network platform technologies and satellite com-munications technologies is being per-formed in conformance with the Fourth Medium- to Long-Term Plan of NICT.Wireless network management technologyWe built prototypes of privately operated mi-crocell radio equipment for the millimeter-wave band (28 GHz) and constructed a simulation environment including management equipment and base stations. We used this environment to demonstrate the feasibility of a proposed system that could be used by multiple operators in Intel-ligent Transport Systems (ITS) and other real-world systems (Fig.1 (a)). Additionally, using a system for reporting the operating information (position, frequency, etc.) of microcell base sta-tions from multiple cellular operators based on control-plane/user-plane separation, we dem-onstrated the possibility of integrating such “pri-vate microcells” with 5G mobile communica-tions and proposed the necessary architecture to the 3rd Generation Partnership Project (3GPP), where it was subsequently adopted.Next, envisioning application in environ-ments such as emergency-supply warehous-es and smart offices, we successfully con-ducted an indoor experiment on massive connectivity assuming 20,000 5G radio ter-minals. In this way, we demonstrated the fea-sibility of using this technology in 5G systems under massive connections on the order of 1,000,000 devices/km2 (Fig.1 (b)).Furthermore, as a technology contributing to efficient frequency utilization, we conduct-ed a basic experiment on massive connectiv-ity under the conditions of five simultaneously connected terminals and a latency time of 5 milliseconds (ms) or less. We submitted a portion of these experimental results to 3GPP RAN 1 as a draft contribution. We also pro-posed a control system to enable high-densi-ty rollout of microcells and submitted a partial system as a draft contribution toward the next-generation wireless LAN standard (IEEE802.11ax). This contribution was accept-ed and is now under discussion. In addition, we proposed an extended Multipath TCP (MPTCP) system to the Internet Engineering Task Force (IETF). The purpose of this system is to individual applications to operate at de-sired transmission speed and latency in com-bination with deep packet inspection tech-nology while simultaneously connecting multiple cellular operators and enabling the sharing of resources on the transport layer. Wireless network customization technologyAmong network structures consisting of multiple units of radio equipment (wireless grid), the high-reliability mesh network is lay-ing the foundation for new application fields. For this type of network, we studied the mod-eling of various wireless adaptation formats for in-factory use and successfully obtained data in a real-world environment in confor-mance with wireless applications (some 130 types) that we analyzed and categorized last fiscal year. We are working to deploy this technology in society by proposing it to a working group of the IEEE 802.1 standard committee and promoting its reflection in a (a) (b) Fig.1 : Wireless network management technology: (a) demonstration of ITS using privately operated microcells, (b) demonstration of a smart ofce using 5G wireless terminalsResearch and Development