Toward Optimal Admission Control and Resource Allocation for LTE-A Femtocell Uplink

The Third-Generation Partnership Project (3GPP) has incorporated femtocell (FC) technology in the Long-Term Evolution Advanced (LTE-A) standard to enhance the quality of service of indoor mobile users and extend the coverage area of existing macrocells (MCs). In such two-tier LTE-A MC/FC systems, cotier and cross-tier interference exists in cochannel deployment, exerting adverse effects on system performance. In this paper, we study the single-carrier frequency-division multiple-access (SC-FDMA)-based LTE-A FC uplink. We propose the use of transport-layer data admission control (AC) in femto user equipment (FUE) and interference-aware resource allocation (RA) in each base station (BS) to manage the intercell interference (ICI). We first formulate the problem as a constrained Markov decision problem (CMDP) that aims at maximizing the time-average throughput of the entire FC tier subject to the queue stability constraint for each FUE. Then, we propose a joint AC and RA (JACRA) algorithm to obtain the optimal AC and RA policies. In light of the NP-hardness of the RA subproblem, we further propose an iterative heuristic with polynomial time complexity. Simulation studies show that the proposed JACRA algorithm is throughput optimal, outperforming alternative proportional fair (PF) and round robin (RR) scheduling schemes. Moreover, the proposed heuristic achieves near-optimal throughput with substantial improvement in computational complexity.