  In this paper, we consider maximizing the sum-rate in the uplink of a
multi-cell OFDMA network. The problem has a non-convex combinatorial structure
and is known to be NP hard. Due to the inherent complexity of implementing the
optimal solution, firstly, we derive an upper and lower bound to the optimal
average network throughput. Moreover, we investigate the performance of a near
optimal single cell resource allocation scheme in the presence of ICI which
leads to another easily computable lower bound. We then develop a centralized
sub-optimal scheme that is composed of a geometric programming based power
control phase in conjunction with an iterative subcarrier allocation phase.
Although, the scheme is computationally complex, it provides an effective
benchmark for low complexity schemes even without the power control phase.
Finally, we propose less complex centralized and distributed schemes that are
well-suited for practical scenarios. The computational complexity of all
schemes is analyzed and performance is compared through simulations. Simulation
results demonstrate that the proposed low complexity schemes can achieve
comparable performance to the centralized sub-optimal scheme in various
scenarios. Moreover, comparisons with the upper and lower bounds provide
insight on the performance gap between the proposed schemes and the optimal
solution.
