Optimal Resource Allocation Algorithm Research Articles

Resource level minimization in the discrete–continuous scheduling

A discrete–continuous problem of non-preemptive task scheduling on identical parallel processors is considered. Tasks are described by means of a dynamic model, in which the speed of the task performance depends on the amount of a single continuously divisible renewable resource allotted to this task over time. An upper bound on the completion time of all the tasks is given. The criterion is to minimize the maximum resource consumption at each time instant, i.e., the resource level. This problem has been observed in many industrial applications, where a continuously divisible resource such as gas, fuel, electric, hydraulic or pneumatic power, etc., has to be distributed among the processing units over time, and it affects their productivity. The problem consists of two interrelated subproblems: task sequencing on processors (discrete subproblem) and resource allocation among the tasks (continuous subproblem). An optimal resource allocation algorithm for a given sequence of tasks is presented and computationally tested. Furthermore, approximation algorithms are proposed, and their theoretical and experimental worst-case performances are analyzed. Computer experiments confirmed the efficiency of all the algorithms.

The Optimal Resource Discovery and Allocation Algorithm for One hop Using Anonymous Arbitrary Topology

A distributed system consists of, possibly heterogeneous, computing nodes connected by communication network that do not share memory or clock. One of the main benefits of distributed systems is resource sharing which speeds up computation, enhances data availability and reliability. However resources must be discovered and allocated before they can be shared. Virtual caching is a new caching scheme which allows a host node to grant authority of caching pages in some fraction of its own cache to nearby nodes. However the virtual caching protocol doesn't mentions how a client node obtains virtual cache from remote host. To address this problem we formulate a resource discovery and allocation problem. We are focusing our attention on how to locate resources-surplus donor nodes and to determine how much of the request for resources of deficient nodes will be satisfied, efficiently in a connected network especially within a finite hop of the resource deficient node. We intend to minimize the amount of unfulfilled request of deficient nodes. Virtual cache allocation can be changed any time depending upon the requirement. Hence the proposed heuristics are efficient both in terms of time and amount of communication performed. We also estimate the quality of distribution achieved by comparing the distribution yielded by the heuristics and by the solution of ILP formulation of the problem. We propose and compare few heuristics for minimizing the amount of unfulfilled request for resources, of deficient nodes when nodes look for resources within finite hops. In this paper we are restricting ourselves to single hop only. For the bounded hops we restrict ourselves to the resource distribution within one hop. By using non-anonymous arbitrary topology with sequence number of request to resolve deadlocks and distributing resources over the original arbitrary network. Sequence number of the request is the unique ID of sender node. We proposed a heuristic to distribute resources over anonymous arbitrary topology by passing a token . The token is privilege to distribute the resources. Each resource surplus node is giving its extra nodes in such a way so that it itself doesn't becomes resource-deficient in the process. Load is not infinitely divisible. We are focusing our attention only to determine how much of the request of each resource deficient node will be satisfied.

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

In a companion paper (see ?Resource Allocation for Downlink Cellular OFDMA Systems-Part I: Optimal Allocation,? IEEE Trans. Signal Process., vol. 58, no. 2, pp. 720-734, Feb. 2010), 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 the optimal resource allocation algorithm of Part I as the number of users in each cell tends to infinity. Our analysis allows to prove that the proposed simplified algorithm is asymptotically optimal, i.e., it achieves the same asymptotic transmit power as the optimal algorithm as the number of users in each cell tends to infinity. As a byproduct of our analysis, we characterize the optimal value of the frequency reuse factor. Simulations sustain our claims and show that substantial performance improvements are obtained when the optimal value of the frequency reuse factor is used.

Admission control and resource allocation in a heterogeneous OFDMA wireless network

We study the problem of admission control and resource (subcarriers, power and bit-loading) allocation in a heterogeneous OFDMA wireless network serving both QoS-constrained high-priority users and best-effort users. By clustering subcarriers, efficient algorithms for cluster and power allocation have been proposed. Our strategy maximizes the total network utility of the best-effort users while satisfying the QoS request for maximum number of high-priority users. We approximate best-effort user utility function as a piece-wise linear function and propose a linear programming based cluster allocation algorithm. The feasibility of the resource allocation problem depends on the number of HP users in the network. Since a large number of demanding HP users would render the resource allocation problem infeasible, a joint admission control and resource allocation scheme could be an efficient way of tackling both problems with less overhead. By incorporating admission control, we propose an efficient and optimal joint admission control and resource allocation algorithm.

Optimal and near-optimal resource allocation algorithms for OFDMA networks

Given the availability of multiple orthogonal channels and multimedia transmission rate requirements from multiple wireless OFDMA users, we are interested in a joint channel, power and rate assignment scheme that satisfies the given requirements with the minimum total transmit power. Algorithms for finding suboptimal and optimal solutions to sum power minimization resource allocation problems in OFDMA-based networks haven been proposed. But the complexity of finding the optimal solution is prohibitively high. We present two efficient algorithms with which each channel (subcarrier) is assigned to at most one user. The first approach, which gives near-optimal solutions, employs a dynamic programming (DP) based tree search and adopts a fair initial condition that offers every user all available channels and removes a channel from all but one user at each stage. Each removal is based on the criterion of the least total power increase. Using the DP-based solution as the initial upper bound and the partial path cost used in the DP approach as the lower bound for each visited node, we develop an efficient branch-and-bound based algorithm that guaranteed to lead to the optimal solution. The average complexities of both algorithms are evaluated and effective schemes to further reduce the required complexity are proposed. We also provide performance and complexity comparisons with other suboptimal algorithms that are modified from the existing ones.

Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks

There are currently a large variety of wireless access networks, including the emerging vehicular ad hoc networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability, and even instantaneous high-bandwidth in some cases. Therefore, it is imperative for network service providers to make the best possible use of the combined resources of available heterogeneous networks (wireless area networks (WLANs), Universal Mobile Telecommunications Systems, VANETs, Worldwide Interoperability for Microwave Access (WiMAX), etc.) for connection support. When connections need to migrate between heterogeneous networks for performance and high-availability reasons, seamless vertical handoff (VHO) is a necessary first step. In the near future, vehicular and other mobile applications will be expected to have seamless VHO between heterogeneous access networks. With regard to VHO performance, there is a critical need to develop algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a VHO decision algorithm that enables a wireless access network to not only balance the overall load among all attachment points (e.g., base stations and access points) but also maximize the collective battery lifetime of mobile nodes (MNs). In addition, when ad hoc mode is applied to 3/4G wireless data networks, VANETs, and IEEE 802.11 WLANs for a more seamless integration of heterogeneous wireless networks, we devise a route-selection algorithm for forwarding data packets to the most appropriate attachment point to maximize collective battery lifetime and maintain load balancing. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed algorithms.

An algorithm for optimal resource allocation in cellular networks with elastic traffic

In this letter we propose a power allocation iteration which optimizes the weighted aggregate performance of a single-hop network. We show that the proposed iteration is a competitive alternative to conventional gradient iterations in terms of convergence and computational effort.

Optimal resource allocation in the OFDMA downlink with imperfect channel knowledge

Previous research efforts on OFDMA resource allocation have typically assumed the availability of perfect channel state information (CSI). Unfortunately, this is unrealistic, primarily due to channel estimation errors, and more importantly, channel feedback delay. In this paper, we develop optimal resource allocation algorithms for the OFDMA downlink assuming the availability of only partial (imperfect) CSI. We consider both continuous and discrete ergodic weighted sum rate maximization subject to total power constraints, and average bit error rate constraints for the discrete rate case. We approach these problems using a dual optimization framework, allowing us to solve these problems with O(MK) complexity per symbol for an OFDMA system with K used subcarriers and M active users, while achieving relative optimality gaps of less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> for continuous rates and less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> for discrete rates in simulations based on realistic parameters.

Resource allocation for non-real-time services in OFDM-based cognitive radio systems

We study the resource allocation (RA) problem in a multiuser OFDM-based cognitive radio (CR) system for non-realtime (NRT) applications in which average user data rates are to be maintained proportionally. In contrast to existing algorithms designed for multiuser OFDM systems, which are unable to guarantee users proportional rates when applied in a CR system, the proposed optimal RA algorithm ensures that CR user rates are maintained in proportion to predefined target rates while at the same time providing an improved system throughput.

Layered resource allocation for video broadcasts over wireless networks

This paper aims to combine adaptive modulation and coding with layered video coding to improve the quality of video services to users experiencing differing radio conditions, in the context of broadcast and multicast standards such as MBMS and BCMCS. We propose an optimal radio resource allocation algorithm which maximizes a general performance metric for a video session in polynomial time. We show that system-wide optimal resource allocation can be obtained by combining our algorithm with a simple two-step decomposition of the system. In some configurations frequent re-allocations of resource are required, so we also present a sub-optimal allocation algorithm which runs in near linear time. Simulation results show better video quality than existing resource allocation schemes over a range of conditions, and also suggest that the difference between the performance of optimal and suboptimal solutions is less than 3%.

Performance Comparison of Downlink Multiuser MIMO-OFDMA and MIMO-MC-CDMA with Transmit Side Information - Multi-Cell Analysis

Orthogonal frequency division multiple access (OFDMA) and multicarrier code division multiple access (MC-CDMA) have recently drawn much attention for being potential candidates of future generation cellular systems. In single-cell scenario, while MC-CDMA is good at achieving frequency diversity when there is no channel state information available at the transmit side (CSIT), OFDMA achieves higher capacity than MC-CDMA due to its finer resolution in exploiting multiuser diversity with CSIT. Whether multiple-input-multiple-output (MIMO) MC-CDMA or OFDMA is a better option in multi-cell system remains unjustified in the literature. In this paper, we study the ergodic capacity and the goodput of MIMO-MC-CDMA and MIMO-OFDMA downlink systems with CSIT in multi-cell scenario assuming that the base station has the knowledge of the average inter-cell interference level only. Several types of users modeling different interference patterns are considered: (I) high data rate delay-insensitive users, (II) high data rate delay-sensitive .users, and (III) voice users (low data rate and bursty). Optimal resource allocation algorithms are used to compute the capacities of the systems, while a simple heuristic is used to obtain the achievable goodputs for both systems. The effects of path loss, number of antennas and different user types are studied and insightful results are obtained. We find that OFDMA has a higher system goodput for both Type I and Type II high data rate users, while MC-CDMA has a higher goodput for Type III users. Compared to MC-CDMA, the goodput of an OFDMA system is more sensitive to the activity factor of the voice users and suffers from noticeable loss. This demonstrates the superiority of the two systems in different practical situations.

A family of incentive-compatible and non-subsidizing optimal resource allocation problems

This paper provides a structure unifying several recent results on an incentive optimal resource allocation problem. They include an incentive-compatible modification of the Heal Algorithm, a generalization of it allowing the formation of secret coalitions and a class of center-free resource allocation algorithms as special cases. Our framework encompasses these earlier results and allows us to characterize a large class of incentive-compatible and non-subsidizing optimal resource allocation algorithms.

A network flow algorithm for optimal resource allocation

Abstract This paper introduces a network flow method for manpower scheduling and resource allocation. The network formulation of the problem permits the development of an algorithm that determines the minimal flow of resources through the network. The method presented here corresponds to the Simplex method, for in both methods the value of the objective function is optimized while the capacity limitations are preserved. The procedure proposed here, however, uses a more economical problem representation and is computationally more efficient. The efficacy of the minimal flow algorithm and its use is illustrated for a production system but the applicability of the procedure is sufficiently broad for it to work in other problem situations just as well.

Joint Optimal Resource Allocation and PAPR Reduction Algorithm for OFDMA Systems

One of the drawbacks of an orthogonal frequency division multiplexing (OFDM) system is the larger peak to averaged power ratio (PAPR). The PAPR reduction scheme is a complicated problem, especially when a resource allocation is considered jointly. In this paper, a joint algorithm for determining an optimal resource allocation with PAPR awareness is proposed. Firstly, an adaptive tone reservation assignment is performed by optimally choosing a group of subcarriers, whose channel gains are sufficiently high, to be the data subcarriers and the remaining subcarriers will be used as the reserved tones for reducing PAPR to the desired level. Secondly, an adaptive power adjustment for PAPR reduction technique is introduced for determining the allocated power of data subcarriers by using the water-filling approach with the joint PAPR and capacity constraints. By using the proposed joint algorithm, the PAPR threshold level is satisfied while the desired capacity could be achieved. From the results, the proposed algorithm achieves the better results comparing with a conventional partial transmit sequence (PTS) technique and the tone reservation (TR) technique in terms of PAPR, and probability of error performances, in which the side information is not required, in contrast with the other techniques.