Abstract
Next generation cellular networks will be heterogeneous with dense deployment of small cells in order to deliver high data rate per unit area. Traffic variations are more pronounced in a small cell, which in turn lead to more dynamic interference to other cells. It is crucial to adapt radio resource management to traffic conditions in such a heterogeneous network (HetNet). This paper studies the optimization of spectrum allocation in HetNets on a relatively slow timescale based on average traffic and channel conditions (typically over seconds or minutes). Specifically, in a cluster with n base transceiver stations (BTSs), the optimal partition of the spectrum into 2n segments is determined, corresponding to all possible spectrum reuse patterns in the downlink. Each BTS's traffic is modeled using a queue with Poisson arrivals, the service rate of which is a linear function of the combined bandwidth of all assigned spectrum segments. With the system average packet sojourn time as the objective, a convex optimization problem is first formulated, where it is shown that the optimal allocation divides the spectrum into at most n segments. A second, refined model is then proposed to address queue interactions due to interference, where the corresponding optimal allocation problem admits an efficient suboptimal solution. Both allocation schemes attain the entire throughput region of a given network. Simulation results show the two schemes perform similarly in the heavy-traffic regime, in which case they significantly outperform both the orthogonal allocation and the full-frequency-reuse allocation. The refined allocation shows the best performance under all traffic conditions.
Original language | English (US) |
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Article number | 7110522 |
Pages (from-to) | 2027-2038 |
Number of pages | 12 |
Journal | IEEE Journal on Selected Areas in Communications |
Volume | 33 |
Issue number | 10 |
DOIs | |
State | Published - Oct 1 2015 |
Keywords
- Spectrum allocation
- dynamic traffic
- heterogeneous network
- interactive queueing
- interference management
- load balancing
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering