Rate Maximization through Structured Spectrum Allocation and User Association in Heterogeneous Cellular Networks

Abstract—We study joint spectrum allocation and user asso-ciation in heterogeneous cellular networks with multiple tiers of base stations. A stochastic geometric approach is applied as the basis to derive the average downlink user data rate in a closed-form expression. Then, the expression is employed as the objective function in jointly optimizing spectrum allocation and user association, which is of non-convex programming in nature. A computationally efficient Structured Spectrum Allocation and User Association (SSAUA) approach is proposed, solving the problem optimally and asymptotically optimally in two regions divided by a parameter specific threshold. A Surcharge Pricing Scheme (SPS) is also presented, such that the designed association bias values can be achieved in Nash equilibrium. Simulations and numerical studies are conducted to validate the accuracy and efficiency of the proposed SSAUA approach and SPS. Index Terms—Heterogeneous cellular network, stochastic ge-ometry, user association, spectrum allocation. I