TY  - JOUR
N2  - IEEE In this paper, we provide joint subcarrier assignment and power allocation schemes for quality-of-service (QoS)-constrained energy-efficiency (EE) optimization in the downlink of an orthogonal frequency division multiple access (OFDMA)-based two-tier heterogeneous cellular network (HCN). Considering underlay transmission, where spectrum-efficiency (SE) is fully exploited, the EE solution involves tackling a complex mixed-combinatorial and non-convex optimization problem. With appropriate decomposition of the original problem and leveraging on the quasi-concavity of the EE function, we propose a dual-layer resource allocation approach and provide a complete solution using difference-of-two-concave-functions approximation, successive convex approximation and gradient-search method. On the other hand, the inherent inter-tier interference from spectrum underlay access may degrade EE particularly under dense small-cell deployment and large bandwidth utilization. We therefore develop a novel resource allocation approach based on the concepts of spectrum overlay access and resource efficiency (RE) (normalized EE-SE trade-off). Specifically, the optimization procedure is separated where the macro-cell optimal RE and the corresponding bandwidth is first determined, then the EE of small-cells utilizing the remaining spectrum is maximized. Simulation results confirm the theoretical findings and demonstrate that the proposed resource allocation schemes can approach the optimal EE with each strategy being superior under certain system settings.
ID  - discovery10042595
KW  - Interference
KW  -  Resource management
KW  -  Bandwidth
KW  -  Optimization
KW  -  Cellular networks
KW  -  Quality of service
KW  -  Power demand
AV  - public
Y1  - 2018/03//
EP  - 2453
TI  - Energy-Efficient Heterogeneous Cellular Networks with Spectrum Underlay and Overlay Access
UR  - https://doi.org/10.1109/TVT.2017.2773506
SN  - 0018-9545
A1  - Tang, J
A1  - So, DKC
A1  - Alsusa, EA
A1  - Hamdi, KA
A1  - Shojaeifard, A
A1  - Wong, KK
JF  - IEEE Transactions on Vehicular Technology
VL  - 67
SP  - 2439
IS  - 3
N1  - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions.
ER  -