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The resource allocation problem for the downlink of Orthogonal Frequency Division Multiple Access (OFDMA) wireless multicast systems is investigated. It is assumed that both the Base Station (BS) and each user are equipped with a single antenna and the allocation unit is not the subcarrier, as in conventional OFDMA systems, but a set of contiguous subcarriers (chunk). The aim of the proposed efficient...
In cognitive radio settings with highly dynamic primary activities and with small opportunities for secondary access, the requirement to fairly distribute the temporarily available spectral ranges among the unlicensed users turns out to be of particular relevance. The current paper addresses this issue by presenting a new design formulation that aims to optimize the performance of an orthogonal-frequency-division-multiple-access...
This paper deals with dynamic resource allocation problem for OFDMA-based cognitive radio systems. The proposed solution is specifically tailored for a secondary base stations (SBS) transmitting to secondary users (SUs) over the same bands of the licensed primary users (PUs) in underlay fashion. The downlink transmission goodput is thereby maximized while keeping the interference on the PUs within...
The IEEE 802.16 standard uses Orthogonal Frequency Division Multiple Access (OFDMA) for mobility support. Therefore, the medium access control frame extends in two dimensions, i.e., time and frequency. At the beginning of each frame, i.e., every 5 ms, the base station is responsible both for scheduling packets, based on the negotiated quality of service requirements, and for allocating them into the...
Uplink ergodic sum-rate maximization in OFDMA systems is considered. The general problem is formulated as a convex optimization problem and a dual solution is presented. The problem formulation is generalized to the case of utility maximization where the utility can be any function of rate. A suboptimal scheduling algorithm with low complexity is proposed and shown to achieve close performance to...
Cognitive radio and OFDMA attracts a lot of attentions in academic and industry fields. In this paper, the asymptotic performance of an uplink radio resource allocation scheme is investigated for OFDMA-based cognitive radio networks. Considering the characteristics of cognitive radio and OFDMA, in the uplink subcarrier allocation algorithm, the subcarriers are allocated to the users with the best...
In this paper, a novel hierarchical algorithm is proposed for orthogonal frequency-division multiple-access wireless mesh networks (WMNs). The problem is to maximize the overall end-to-end rate with balancing the fairness among users, and find a new method as a substitute for Lee's resource allocation algorithm with high computational complexity. The proposed algorithm consists of two subproblems,...
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