Mizutani, Keiichi; Sakaguchi, Kei (Graduate School of Science and Engineering, Tokyo Institute of Technology)
Haustein, Thomas (Heinrich-Hertz-Institute, Fraunhofer Institute for Telecommunication, Berlin, Germany)
In this paper, a data sharing system using a coordinator with layered transmission is proposed. We focus on secured data connections from all users to all users of the conferencing group. A typical example is secured group communication between a group of users e.g. a social group during a multi-user audio or video conference. Secured unicast scheme, secured broadcast scheme, and network coding scheme are considered for the data distribution scheme in downlink. The layered transmission can achieve improvement of the network throughput. In addition, the hierarchical modulation is introduced to improve the network throughput, and an effective region of the hierarchical modulation is shown. Finally, the network throughput of the secured unicast, the secured broadcast, and the network coding is compared, and we find that the network coding is the most effective scheme for the data sharing system using the coordinator with layered transmission.