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**1 - 9**of**9**### An analytical framework for heterogeneous partial feedback design in heterogeneous multicell ofdma networks

- IEEE Transactions on Signal Processing
, 2013

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### Nearly optimal resource allocation for downlink OFDMA in 2-D cellular networks

- IEEE Trans. Wireless Commun
, 2011

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### OFDMA Systems: Part I—Optimal Allocation

"... In this pair of papers (Part I and Part II in this issue), we investigate the issue of power control and subcarrier assignment in a sectorized two-cell downlink OFDMA system impaired by multicell interference. As recommended for WiMAX, we assume that the first part of the available bandwidth is like ..."

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In this pair of papers (Part I and Part II in this issue), we investigate the issue of power control and subcarrier assignment in a sectorized two-cell downlink OFDMA system impaired by multicell interference. As recommended for WiMAX, we assume that the first part of the available bandwidth is likely to be reused by different base stations (and is thus subject to multicell interference) and that the second part of the bandwidth is shared in an orthogonal way between the different base stations (and is thus protected from multicell interference). Although the problem of multicell resource allocation is nonconvex in this scenario, we provide in Part I the general form of the global solution. In particular, the optimal resource allocation turns out to be “binary ” in the sense that, except for at most one pivot-user in each cell, any user receives data either in the reused bandwidth or in the protected bandwidth, but not in both. The determination of the optimal resource allocation essentially reduces to the determination of the latter pivot-position.

### Resource Allocation for Downlink Cellular 1 OFDMA Systems: Part II—Practical Algorithms and Optimal Reuse Factor

, 2009

"... In a companion paper (see Resource Allocation for Downlink Cellular OFDMA Systems: Part I — Optimal Allocation), we characterized the optimal resource allocation in terms of power control and subcarrier assignment, for a downlink sectorized OFDMA system impaired by multicell interference. In our mod ..."

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In a companion paper (see Resource Allocation for Downlink Cellular OFDMA Systems: Part I — Optimal Allocation), we characterized the optimal resource allocation in terms of power control and subcarrier assignment, for a downlink sectorized OFDMA system impaired by multicell interference. In our model, the network is assumed to be one dimensional (linear) for the sake of analysis. We also assume that a certain part of the available bandwidth is likely to be reused by different base stations while that the other part of the bandwidth is shared in an orthogonal way between these base stations. The optimal resource allocation characterized in Part I is obtained by minimizing the total power spent by the network under the constraint that all users ’ rate requirements are satisfied. It is worth noting that when optimal resource allocation is used, any user receives data either in the reused bandwidth or in the protected bandwidth, but not in both (except for at most one pivot-user in each cell). We also proposed an algorithm that determines the optimal values of users ’ resource allocation parameters. As a matter of fact, the optimal allocation algorithm proposed in Part I requires a large number of operations. In the present paper, we propose a distributed practical resource allocation algorithm with low complexity. We study the asymptotic behavior of both this simplified resource allocation algorithm and

### Distributed Resource Allocation for Downlink Multicell OFDMA Systems

"... Abstract — This paper addresses resource allocation for sum throughput maximization in a sectorized two-cell downlink OFDMA systems impaired by multicell interference. It is well known that the optimization problem for this scenario is NPhard and combinational, which is here converted to a novel sum ..."

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Abstract — This paper addresses resource allocation for sum throughput maximization in a sectorized two-cell downlink OFDMA systems impaired by multicell interference. It is well known that the optimization problem for this scenario is NPhard and combinational, which is here converted to a novel sum throughput maximization problem based on the intercell interference limitation. Then, two subclasses of this new problem are solved. By the first subclass, on the assumption that subcarrier allocation parameters are fixed, an algorithm for optimal power allocation is obtained. By the second subclass, the problem is reduced to a single cell case where the intercell interference in each subcarrier is limited to a certain threshold. The solution shows that the subcarrier allocation can be performed prior to power distribution. Based on the solution of the single cell problem, a distributed resource allocation scheme with the aim of small information exchange between the coordinated base stations is proposed. Keywords- Dual method, multicell resource allocation, OFDMA, interference limitation, convex optimization, O I.

### Resource Allocation for Downlink Cellular 1 OFDMA Systems: Part I—Optimal Allocation

, 811

"... In this pair of papers (Part I and Part II in this issue), we investigate the issue of power control and subcarrier assignment in a sectorized two-cell downlink OFDMA system impaired by multicell interference. As recommended for WiMAX, we assume that the first part of the available bandwidth is like ..."

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In this pair of papers (Part I and Part II in this issue), we investigate the issue of power control and subcarrier assignment in a sectorized two-cell downlink OFDMA system impaired by multicell interference. As recommended for WiMAX, we assume that the first part of the available bandwidth is likely to be reused by different base stations (and is thus subject to multicell interference) and that the second part of the bandwidth is shared in an orthogonal way between the different base stations (and is thus protected from multicell interference). Although the problem of multicell resource allocation is nonconvex in this scenario, we provide in Part I the general form of the global solution. In particular, the optimal resource allocation turns out to be “binary ” in the sense that, except for at most one pivot-user in each cell, any user receives data either in the reused bandwidth or in the protected bandwidth, but not in both. The determination of the optimal resource allocation essentially reduces to the determination of the latter pivot-position.

### Research Article A Low-Complexity Transmission and Scheduling Scheme for WiMAX Systems with Base Station Cooperation

"... License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper considers base station cooperation as an interference management technique for the downlink of a WiMAX network (IEEE 802.16 standard) with frequency reuse f ..."

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License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper considers base station cooperation as an interference management technique for the downlink of a WiMAX network (IEEE 802.16 standard) with frequency reuse factor of 1. A low-complexity cooperative transmission and scheduling scheme is proposed that requires limited feedback from the users and limited information exchange between the base stations. The proposed scheme requires minor modifications to the legacy IEEE 802.16e systems. The performance of the proposed scheme is compared with noncooperative schemes with similar complexity through computer simulations. Results demonstrate that base station cooperation provides an attractive solution for mitigating the cochannel interference and increases the system spectral efficiency compared to traditional cellular architectures based on frequency reuse. 1.

### 1Low complexity resource allocation for load minimization in OFDMA wireless networks

"... To cope with the ever increasing demand for bandwidth, future wireless networks will be designed with reuse distance equal to one. This scenario requires the implementation of techniques able to manage the strong multiple access interference each cell generates towards its neighbor cells. In particu ..."

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To cope with the ever increasing demand for bandwidth, future wireless networks will be designed with reuse distance equal to one. This scenario requires the implementation of techniques able to manage the strong multiple access interference each cell generates towards its neighbor cells. In particular, low complexity and reduced feedback are important requirements for practical algorithms. In this paper we study an allocation problem for OFDMA networks formulated with the objective of minimizing the load of each cell in the system subject to the constraint that each user meets its target rate. We decompose resource allocation into two sub-problems: channel allocation under deterministic power assignment and continuous power assignment optimization. Channel allocation is formulated as the problem of finding the maximum weighted independent set (MWIS) in graph theory. In addition, we propose a minimal weighted-degree greedy (MWDG) algorithm of which the approximation factor is analyzed. For power allocation, an iterative power reassignment algorithm (DPRA) is proposed. The control information requested to perform the allocation is limited and the computational burden is shared between the base station and the user equipments. Simulations have been carried out under constant bit rate traffic model and the results have been compared with other allocation schemes of similar complexity. MWDG has excellent performance and outperforms all other techniques. Index Terms Resource allocation; power assignment; admission control; NP-hard; maximum weighted indepen-dent set ar X iv

### Dynamic Frequency Allocation in OFDMA Cellular Networks

, 2013

"... Abstract The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. We propose user and sub-channel priority based resource allocation for mobile multimedia ser ..."

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Abstract The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. We propose user and sub-channel priority based resource allocation for mobile multimedia services in the OFDMA systems. Our method is able to guarantee QoS continuity of realtime services and carry the maximum number of non-realtime subscriber. Simulation is focused on total throughput and blocking rate. The simulation results show