On Using the Low-Duty Operation Mode for Interference Mitigation in 802.16 Femtocells
Date Issued
2010
Date
2010
Author(s)
Hsu, Chien-Chun
Abstract
In two-tier networks, due to characteristics of short service range, great of number and ad-hoc deployment in femtocell, the processing of interference to the upper tier is a critical issue. In next-generation mobile system, IEEE 802.16m, the low-duty operation mode is proposed to reduce interference from neighboring femtocells. When the femtocell without any service user or all users operating in sleep mode, the femtocell can enter low-duty operation mode and periodically control transmission for reducing interference to neighbors. Due to the limitation of operation, this reactive low-duty operation mode can not mitigate interference widely and effectively.
In this thesis, we propose a proactive low-duty operation mode, combined with resource allocation to manage interference in femtocell networks. Then we construct a optimization model, and it can maximize system capacity and reduce the interference to upper tier under satisfying user''s requirement. To resolve this optimization problem, we then reformulate it into linear programming problem with controlling approximation error. Using this optimization model, we first investigate in different network environments the optimal parameters of low-duty operation mode, including its duty cycle length and available interval ratio. Secondly, due to global information requirement and high complexity of optimization framework, we propose a two-stage algorithm to reduce computational complexity. The simulation results show that this two-stage algorithm around 10% at the expense of system capacity, it can reduce more than 90% computation complexity, and can effectively manage interference in femtocell networks.
Subjects
Femtocell
Low duty operation mode
Type
thesis
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