Title
Allocation of licensed and unlicensed spectrum in heterogeneous networks
Abstract
In order to support fast growing mobile data traffic, wireless operators have started to use multiple radio access technologies (RATs) over multiple licensed and unlicensed frequency bands. A widely used method is WiFi off-loading of cellular network traffic. A recent proposal is side-by-side deployment of Long Term Evolution (LTE) in licensed spectrum and LTE in unlicensed spectrum (LTE-U). This paper studies the spectrum allocation problem in such heterogeneous networks (HetNets). For practical reasons, the allocation is conceived to be on a relatively slow timescale. A queueing model is introduced for the unlicensed band to capture its lower spectral efficiency, reliability, and additional delay due to contention and/or listen-before-talk requirements. Under mild assumptions, the spectrum allocation problem is formulated as a bi-convex optimization problem. Solving this problem gives an effective and computationally efficient solution for both user association and spectrum allocation over multiple RATs. Simulation results show that in the heavy-traffic regime, the proposed scheme significantly outperforms both orthogonal and full-frequency-reuse allocations. In addition, the solution to the optimization problem matches the intuition that users with relatively higher traffic demand are mostly assigned to the licensed spectrum, while those with lower traffic demand and less exogenous interference from the unlicensed band are assigned to the unlicensed spectrum.
Year
DOI
Venue
2016
10.1109/AusCTW.2016.7433610
2016 Australian Communications Theory Workshop (AusCTW)
Keywords
Field
DocType
unlicensed spectrum,licensed spectrum,heterogeneous networks,mobile data traffic,multiple radio access technologies,RAT,WiFi off-loading,cellular network traffic,Long Term Evolution,LTE,bi-convex optimization problem,spectrum allocation problem
Wireless,Spectrum management,Computer science,Computer network,Spectral efficiency,Cellular network,Frequency allocation,Heterogeneous network,LTE in unlicensed spectrum,Radio spectrum
Conference
Volume
Citations 
PageRank 
abs/1507.08010
3
0.42
References 
Authors
12
3
Name
Order
Citations
PageRank
Zhiyi Zhou171.57
Dongning Guo22150137.56
Michael L. Honig32971411.29