{JS} J. Jang, H. J. Yang, and H. Jwa, “Resource Allocation and Power Control in Cooperative Small Cell Networks with Backhaul Constraint” submitted

A joint resource allocation (RA), user association (UA),
and power control (PC) problem is addressed for proportional fairness
(PF) maximization in a cooperative multiuser downlink small cell
network with limited backhaul capacity, based on orthogonal frequency
division multiplexing. Previous studies have relaxed the per-resourceblock
(RB) RA and UA problem to a continuous optimisation problem
based on long-term signal-to-noise ratio, because the original problem
is known as a combinatorial NP-hard problem. We tackle the original
per-RB RA and UA problem to obtain a near-optimal solution with
feasible complexity. We show that the conventional dual problem
approach for RA cannot find the solution satisfying the conventional
KKT conditions. Inspired by the dual problem approach, however,
we derive the first order optimality conditions for the considered
RA, UA, and PC problem, and propose a sequential optimization
method for finding the solution. The overall proposed scheme can
be implemented with feasible complexity even with a large number
of system parameters. With the aid of numerical programming, we
characterize a loose PF outer-bound by assuming no power constraint
or backhaul capacity constraint. Numerical results show that the
proposed scheme achieves the PF close to its outer bound.