Multi-group multi-way relaying with multi-stage non-regenerative relay stations

In this paper, we propose a signal transmission model for multi-group multi-way (MGMW) relaying which allows complete information exchange among users belonging to different user groups, with applications such as file sharing among users separated by large distances. We achieve this through the use of multi-stage non-regenerative relay stations (RSs). The groups of multiple users are connected to the nearest RS stages which are again connected via RSs at the next nearest stage and so on. The RSs at each stage obtain messages from user groups connected through the next RS stage by subtracting information extracted from the previous RS stage. We formulate the achievable sum rate of such a network and investigate the impact of system parameters on it. We show that increasing the number of users per group, while keeping a smaller number of user groups, improves the sum rate.