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Dynamic Orthogonal Frequency Division Multiple Access resource management for downlink interference avoidance in two‐tier networks
Author(s) -
Kao ShangJuh,
Wang HsiuLang
Publication year - 2013
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.2668
Subject(s) - computer science , femtocell , macrocell , orthogonal frequency division multiple access , computer network , telecommunications link , superframe , frequency allocation , channel allocation schemes , orthogonal frequency division multiplexing , channel (broadcasting) , wireless , telecommunications , base station , frame (networking)
SUMMARY In two‐tier networks, which consist of macrocells and femtocells, femtocells can offload the traffic from macrocells thereby improving indoor signal coverage. However, the dynamic deployment feature of femtocells may result in signal interference due to limited frequency spectrum. The tradeoff between broad signal coverage and increased signal interference deserves further exploration for practical network operation. In this paper, dynamic frequency resource management is proposed to avoid both co‐tier and cross‐tier Orthogonal Frequency Division Multiple Access downlink interference and increase frequency channel utilization under co‐channel deployment. A graph‐based non‐conflict group discovery algorithm is proposed to discover the disjoint interference‐free groups among femtocells in order to avoid the co‐tier interference. A macrocell uses the femtocell gateway for frequency resource allocation among femtocells to avoid cross‐tier interference. We formulate the optimized frequency resource assignment as a fractional knapsack problem and solve the problem by using a greedy method. The simulation results show that the average data transfer rate can be increased from 21 % to 60 % , whereas idle rate and blocking rate are decreased in the range of 1 5 % ∽ 2 2 % and 6 0 % ∽ 8 2 % , respectively, as compared with conventional graph coloring and graph‐based dynamic frequency reuse schemes. Copyright © 2013 John Wiley & Sons, Ltd.