Resource Allocation for Maximizing Weighted Sum Min-Rate in Downlink Cellular OFDMA Systems (original) (raw)
Related papers
IEEE Transactions on Signal Processing, 2000
This paper considers the downlink of a cellular orthogonal frequency division multi-access (OFDMA) system, in which multiple base stations (BSs) are coordinated by a centralized resource allocation algorithm. We address the problem of maximizing the weighted sum of the minimal user rates (WSMR) of coordinated cells subject to a total power constraint at each BS, in terms of jointly optimizing coordinated BSs' subcarrier and power allocation. In particular, the solution of this problem corresponds to a resource allocation that guarantees similar rates to all users in each cell. An iterative algorithm is proposed to optimize the subcarrier allocation and the power allocation alternatively, so that the WSMR keeps increasing until convergence. In each iteration, the subcarrier allocation is updated by solving a mixed integer linear program for each cell, while the power allocation is updated by solving a successive set of convex optimization problems with a duality-based numerical algorithm. The effectiveness of the algorithm is illustrated by numerical experiments.
2012
This paper considers the downlink of a cellular orthogonal frequency division multi-access (OFDMA) system, in which multiple base stations (BS) are coordinated by a centralized resource allocation algorithm. We address the problem of maximizing the weighted sum min-rate (WSMR) subject to a total power constraint at each BS, in terms of jointly optimizing coordinated BSs' subcarrier and power allocation. In particular, this problem leads to a resource allocation that guarantees similar rates to users in each cell. An iterative algorithm is proposed to optimize subcarrier and power allocation alternatively, so that the WSMR keeps increasing until convergence. In each iteration, the subcarrier allocation is updated by solving a mixed integer linear programming problem for each cell, while the power allocation is updated by solving a successive set of convexoptimization problems with an algorithm based on Karush-Kuhn-Tucker conditions. The effectiveness of the algorithm is illustrated by numerical experiments.
2010 IEEE 21st International Symposium on Personal, Indoor and Mobile Radio Communications Workshops, 2010
This paper considers the downlink of a cellular orthogonal frequency division multi-access (OFDMA) system, in which multiple base stations (BSs) are coordinated by a centralized resource allocation algorithm. We address the problem of maximizing the weighted sum of the minimal user rates (WSMR) of coordinated cells subject to a total power constraint at each BS. In particular, the solution of this problem corresponds to a resource allocation that guarantees similar rates to users in each cell. We propose a coordinate ascent based iterative algorithm which alternatively updates the power allocation by solving a successive set of convex optimization problems with geometric programming, as well as optimizes the subcarrier allocation by solving a linear program for each cell. We illustrate the effectiveness of the algorithm by numerical experiments.
Distributed Resource Optimization in Multicell OFDMA Networks
2012
We consider the joint allocation of receiver, bit, and power to subcarriers in the downlink of multicell orthogonal frequency-division multiple-access (OFDMA) networks. Assuming that the cells share the entire bandwidth and that the rates are discrete, we formulate the joint allocation problem as a nonlinear mixed integer program (MIP), which however has exponential worst-case complexity. We capitalize on the capability of the receivers to measure the interference-plus-noise on every subcarrier and decompose the joint problem into a set of smaller-scale linear MIPs solved by individual base stations. Accordingly, we propose a distributed algorithm with linear complexity, in which the base stations participate in the problem solution in a round-robin manner. Simulation results demonstrate the effectiveness of the proposed algorithm in comparison with the iterative waterfilling algorithm and the successive optimal solution, by means of standard branch-and-cut solvers, of the individual MIPs.
Resource allocation via sum-rate maximization in the uplink of multi-cell OFDMA networks
Wireless Communications and Mobile Computing, 2011
In this paper, we consider maximizing the sum-rate in the uplink of a multi-cell OFDMA network. The problem has a non-convex combinatorial structure and is known to be NP hard. Due to the inherent complexity of implementing the optimal solution, firstly, we derive an upper and lower bound to the optimal average network throughput. Moreover, we investigate the performance of a near optimal single cell resource allocation scheme in the presence of ICI which leads to another easily computable lower bound. We then develop a centralized sub-optimal scheme that is composed of a geometric programming based power control phase in conjunction with an iterative subcarrier allocation phase. Although, the scheme is computationally complex, it provides an effective benchmark for low complexity schemes even without the power control phase. Finally, we propose less complex centralized and distributed schemes that are well-suited for practical scenarios. The computational complexity of all schemes is analyzed and performance is compared through simulations. Simulation results demonstrate that the proposed low complexity schemes can achieve comparable performance to the centralized sub-optimal
Sum rate maximization in the uplink of multi-cell OFDMA networks
2011 7th International Wireless Communications and Mobile Computing Conference, 2011
Resource allocation in orthogonal frequency division multiple access (OFDMA) networks plays an imperative role to guarantee the system performance. However, most of the known resource allocation schemes are focused on maximizing the local throughput of each cell, while ignoring the significant effect of inter-cell interference. This paper investigates the problem of resource allocation (i.e., subcarriers and powers) in the uplink of a multi-cell OFDMA network. The problem has a non-convex combinatorial structure and is known to be NP hard. Firstly, we investigate the upper and lower bounds to the average network throughput due to the inherent complexity of implementing the optimal solution. Later, a centralized sub-optimal resource allocation scheme is developed. We further develop less complex centralized and distributed schemes that are well-suited for practical scenarios. The computational complexity of all schemes has been analyzed and the performance is compared through numerical simulations. Simulation results demonstrate that the distributed scheme achieves comparable performance to the centralized resource allocation scheme in various scenarios.
Centralized multi-cell resource and power allocation for multiuser OFDMA networks
2016 IFIP Networking Conference (IFIP Networking) and Workshops, 2016
Multiuser Orthogonal Frequency Division Multiple Access (OFDMA) networks, such as Long Term Evolution networks, use the frequency reuse-1 model to face the tremendous increase of mobile traffic demands, and to increase network capacity. However, inter-cell interference problems are generated, and they have a negative impact on cell-edge users performance. Resource and power allocation should be managed in a manner that alleviates the negative impact of inter-cell interference on system performance. In this paper, we formulate a novel centralized multi-cell resource and power allocation problem for multiuser OFDMA networks. The objective is to maximize system throughput while guaranteeing a proportional fair rate for all the users. We decompose the joint problem into two independent problems: a resource allocation problem and a power allocation problem. We prove that each of these problems is a convex optimization problem, and that their optimal solution is also an optimal solution to the original joint problem. Lagrange duality theory and subgradient projection method are used to solve the centralized power allocation problem. We study the convergence of our centralized approach, and we find out that it reduces intercell interference, and increases system throughput and spectral efficiency in comparison with the frequency reuse-1 model, reuse-3 model, fractional frequency reuse, and soft frequency reuse techniques.
2007
We consider the maximization of the weighted sum-rate on a multiuser-OFDM downlink with adaptive modulation and power under a total transmit power constraint and a user-wise target BER. We allow each subcarrier to be shared by more than one user. We show that this optimization problem can be decomposed into two subproblems: a subcarrier assignment and a power allocation. We prove that the optimal subcarrier assignment is exclusive, that is each subcarrier is allocated to only one user. The optimal power allocation corresponds to a multilevel water-filling. When the achievable rate region is convex, the optimality of the exclusive subcarrier assignment for arbitrary weights means that the OFDMA is the optimal sharing scheme for various performance criteria.
A Survey on Resource Allocation in OFDMA Using Convex Optimization
2015
Orthogonal Frequency Division Multiple Access (OFDMA) is the promising technique for ever increasing demand of high data rate services. This paper proposes the Resource allocation issues for multiuser wireless transmissions, based on orthogonal frequency division multiple Access (OFDMA) and convex optimization techniques which are widely used in the design and analysis of variety of communications problems. By using convex optimization we convert the highly non convex resource allocation problem into a sequence of convex sub problems. The proposed system will be designed, to solve the subcarrier and power allocation problems for multiuser OFDMA system. The aim of proposed system is to maximize total throughput while maintaining rate proportionality among the users and minimizing the total transmit power under the condition that the QoS requirement of each user can be guaranteed.
2012
Tackling problems from the least complicated to the most, Resource Allocation in Uplink OFDMA Wireless Systems provides readers with a comprehensive look at resource allocation and scheduling techniques (for both single and multi-cell deployments) in uplink OFDMA wireless networksrelying on convex optimization and game theory to thoroughly analyze performance.Inside, readers will find topics and discussions on: Formulating and solving the uplink ergodic sum-rate maximization problem Proposing suboptimal algorithms that achieve a close performance to the optimal case at a considerably reduced complexity and lead to fairness when the appropriate utility is used Investigating the performance and extensions of the proposed suboptimal algorithms in a distributed base station scenario Studying distributed resource allocation where users take part in the scheduling process, and considering scenarios with and without user collaboration Formulating the sum-rate maximization problem in a mult...