It is shown that a greedy orthogonal access scheme achieves the sum degrees of freedom (DoF) of all one-dimensional (all nodes placed along a straight line) convex cellular networks (where cells are convex regions) when no channel knowledge is available at the transmitters except the knowledge of the network topology. In general, optimality of orthogonal access holds neither for two-dimensional convex cellular networks nor for one-dimensional non-convex cellular networks, thus revealing a fundamental limitation that arises when both one-dimensional and convex properties are simultaneously enforced. The result also establishes the sum capacity of the corresponding class of index coding problems. Index Terms-Cellular networks, interference, degrees of freedom, index coding.
Further, in REF , necessary and sufficient conditions were characterized for the optimality of orthogonal access schemes for the TIM problem in cellular networks.
Optimality of Orthogonal Access for One-Dimensional Convex Cellular Networks
IEEE Communications Letters
IEEE Communications Letters
Mathematics Computer Science