Achievable Degrees of Freedom Region of the MIMO Relay Networks using the Detour Schemes
arXiv:1307.0685
Abstract
In this paper, we study the degrees of freedom (DoF) of the MIMO relay networks. We start with a general Y channel, where each user has antennas and aims to exchange messages with the other two users via a relay equipped with antennas. Then, we extend our work to a general 4-user MIMO relay network. Unlike most previous work which focused on the total DoF of the network, our aim here is to characterize the achievable DoF region as well. We develop an outer bound on the DoF region based on the notion of one sided genie. Then, we define a new achievable region using the Signal Space Alignment (SSA) and the Detour Schemes. Our achievable scheme achieves the upper bound for certain conditions relating 's and .
6 pages, 2 figure, to appear in ICC 2014