Using lagrangian relaxation for radio resource allocation in high altitude platforms

Show simple item record Ibrahim, Ahmed Alfa, Attahiru Sule 2016-06-20T08:33:05Z 2016-06-20T08:33:05Z 2015-10
dc.description.abstract In this paper, we study radio resource allocation for multicasting in OFDMA based high altitude platforms (HAPs). We formulate and solve an optimization problem that finds the best allocation of HAP resources such as radio power, subchannels, and time slots. The problem also finds the best possible frequency reuse across the cells that constitute the service area of the HAP. The objective is to maximize the number of user terminals that receive the requested multicast streams in the HAP service area in a given OFDMA frame. A bounding subroutine in a branch and bound algorithm can be obtained by decomposing it into two easier subproblems, due to its high complexity, and solving them iteratively. Subproblem1 turns out to be a binary integer linear program of no explicitly noticeable structure and therefore Lagrangian relaxation is used to dualize some constraints to get a structure that is easy to solve. Subproblem 2 turns out to be a linear program with a continuous knapsack problem structure. Hence a greedy algorithm is proposed to solve subproblem 2 to optimality. The subgradient method is used to solve for the dual variables in the dual problem to get the tightest bounds. en_ZA
dc.description.department Electrical, Electronic and Computer Engineering en_ZA
dc.description.librarian hb2016 en_ZA
dc.description.uri en_ZA
dc.identifier.citation Ibrahim, A & Alfa, AS 2015, 'Using lagrangian relaxation for radio resource allocation in high altitude platforms', IEEE Transactions on Wireless Communications, vol. 14, no. 10, pp. 5823-2835. en_ZA
dc.identifier.issn 1536-1276
dc.identifier.other 10.1109/TWC.2015.2443095
dc.language.iso en en_ZA
dc.publisher Institute of Electrical and Electronics Engineers en_ZA
dc.rights © 2015 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. en_ZA
dc.subject Multicasting en_ZA
dc.subject Radio resource allocation en_ZA
dc.subject Continuous knapsack problem en_ZA
dc.subject Lagrangian relaxation en_ZA
dc.subject High altitude platforms (HAPs) en_ZA
dc.title Using lagrangian relaxation for radio resource allocation in high altitude platforms en_ZA
dc.type Postprint Article en_ZA

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