Results 1  10
of
21
A tutorial on crosslayer optimization in wireless networks
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2006
"... This tutorial paper overviews recent developments in optimization based approaches for resource allocation problems in wireless systems. We begin by overviewing important results in the area of opportunistic (channelaware) scheduling for cellular (singlehop) networks, where easily implementable my ..."
Abstract

Cited by 240 (27 self)
 Add to MetaCart
(Show Context)
This tutorial paper overviews recent developments in optimization based approaches for resource allocation problems in wireless systems. We begin by overviewing important results in the area of opportunistic (channelaware) scheduling for cellular (singlehop) networks, where easily implementable myopic policies are shown to optimize system performance. We then describe key lessons learned and the main obstacles in extending the work to general resource allocation problems for multihop wireless networks. Towards this end, we show that a cleanslate optimization based approach to the multihop resource allocation problem naturally results in a “loosely coupled” crosslayer solution. That is, the algorithms obtained map to different layers (transport, network, and MAC/PHY) of the protocol stack are coupled through a limited amount of information being passed back and forth. It turns out that the optimal scheduling component at the MAC layer is very complex and thus needs simpler (potentially imperfect) distributed solutions. We demonstrate how to use imperfect scheduling in the crosslayer framework and describe recently developed distributed algorithms along these lines. We conclude by describing a set of open research problems.
On the Complexity of Scheduling in Wireless Networks
 MOBICOM '06
, 2006
"... We consider the problem of throughputoptimal scheduling in wireless networks subject to interference constraints. We model the interference using a family of Khop interference models. We define a Khop interference model as one for which no two links within K hops can successfully transmit at the ..."
Abstract

Cited by 125 (3 self)
 Add to MetaCart
We consider the problem of throughputoptimal scheduling in wireless networks subject to interference constraints. We model the interference using a family of Khop interference models. We define a Khop interference model as one for which no two links within K hops can successfully transmit at the same time (Note that IEEE 802.11 DCF corresponds to a 2hop interference model.). For a given K, a throughputoptimal scheduler needs to solve a maximum weighted matching problem subject to the Khop interference constraints. For K = 1, the resulting problem is the classical Maximum Weighted Matching problem, that can be solved in polynomial time. However, we show that for K> 1, the resulting problems are NPHard and cannot be approximated within a factor that grows polynomially with the number of nodes. Interestingly, we show that for specific kinds of graphs, that can be used to model the underlying connectivity graph of a wide range of wireless networks, the resulting problems admit polynomial time approximation schemes. We also show that a simple greedy matching algorithm provides a constant factor approximation to the scheduling problem for all K in this case. We then show that under a setting with singlehop traffic and no rate control, the maximal scheduling policy considered in recent related works can achieve a constant fraction of the capacity region for networks whose connectivity graph can be represented using one of the above classes of graphs. These results are encouraging as they suggest that one can develop distributed algorithms to achieve near optimal throughput in case of a wide range of wireless networks.
Performance of Random Access Scheduling Schemes in Multihop Wireless Networks
"... The scheduling problem in multihop wireless networks has been extensively investigated. Although throughput optimal scheduling solutions have been developed in the literature, they are unsuitable for multihop wireless systems because they are usually centralized and have very high complexity. In ..."
Abstract

Cited by 69 (7 self)
 Add to MetaCart
(Show Context)
The scheduling problem in multihop wireless networks has been extensively investigated. Although throughput optimal scheduling solutions have been developed in the literature, they are unsuitable for multihop wireless systems because they are usually centralized and have very high complexity. In this paper, we develop a randomaccess based scheduling scheme that utilizes local information. The important features of this scheme include constanttime complexity, distributed operations, and a provable performance guarantee. Analytical results show that it guarantees a larger fraction of the optimal throughput performance than the stateoftheart. Through simulations with both singlehop and multihop traffics, we observe that the scheme provides high throughput, close to that of a wellknown highlyefficient centralized greedy solution called the Greedy Maximal Scheduler.
Supplement for Joint Congestion Control and Distributed Scheduling for Throughput Guarantees in Wireless Networks
, 2009
"... We consider the problem of throughputoptimal crosslayer design of wireless networks. We propose a joint congestion control and scheduling algorithm that achieves a fraction 1/dI(G) of the capacity region, where dI(G) depends on certain structural properties of the underlying connectivity graph G o ..."
Abstract

Cited by 24 (3 self)
 Add to MetaCart
We consider the problem of throughputoptimal crosslayer design of wireless networks. We propose a joint congestion control and scheduling algorithm that achieves a fraction 1/dI(G) of the capacity region, where dI(G) depends on certain structural properties of the underlying connectivity graph G of the wireless network, and also on the type of interference constraints. For a wide range of wireless networks, dI(G) can be upper bounded by a constant, independent of the number of nodes in the network. The scheduling element of our algorithm is the maximal scheduling policy. Although this scheduling policy has been considered in several previous works, the challenges underlying its practical implementation in a fully distributed manner while accounting for necessary message exchanges have not been addressed in the literature. In this paper, we propose two algorithms for the distributed implementation of the maximal scheduling policy accounting for message exchanges, and analytically show that they still can achieve the performance guarantee under the 1hop and 2hop interference models. We also evaluate the performance of our crosslayer solutions in more realistic network settings with imperfect synchronization under the signaltointerferenceplusnoise ratio (SINR) interference model, and compare with the standard layered approaches such as TCP over IEEE 802.11b DCF networks.
Resource allocation in multiradio multichannel multihop wireless networks
 IEEE INFOCOM 2008
, 2008
"... Abstract—A joint congestion control, channel allocation and scheduling algorithm for multichannel multiinterface multihop wireless networks is discussed. The goal of maximizing a utility function of the injected traffic, while guaranteeing queues stability, is defined as an optimization problem w ..."
Abstract

Cited by 19 (0 self)
 Add to MetaCart
(Show Context)
Abstract—A joint congestion control, channel allocation and scheduling algorithm for multichannel multiinterface multihop wireless networks is discussed. The goal of maximizing a utility function of the injected traffic, while guaranteeing queues stability, is defined as an optimization problem where the input traffic intensity, channel loads, interface to channel binding and transmission schedules are jointly optimized by a dynamic algorithm. Due to the inherent NPHardness of the scheduling problem, a simple centralized heuristic is used to define a lower bound for the performance of the whole optimization algorithm. The behavior of the algorithm for different numbers of channels, interfaces and traffic flows is shown through simulations. I.
Toward tractable computation of the capacity of multihop wireless networks
 IEEE INFOCOM 2007 PROCEEDINGS
, 2007
"... ..."
(Show Context)
Adaptive Instantiation of the Protocol Interference Model in Wireless Networked Sensing and Control
"... Interference model is the basis of MAC protocol design in wireless networked sensing and control, and it directly affects the efficiency and predictability of wireless messaging. To exploit the strengths of both the physical and the protocol interference models, we analyze how network traffic, link ..."
Abstract

Cited by 12 (8 self)
 Add to MetaCart
Interference model is the basis of MAC protocol design in wireless networked sensing and control, and it directly affects the efficiency and predictability of wireless messaging. To exploit the strengths of both the physical and the protocol interference models, we analyze how network traffic, link length, and wireless signal attenuation affect the optimal instantiation of the protocol model. We also identify the inherent tradeoff between reliability and throughput in the model instantiation. Our analysis sheds light on the open problem of efficiently optimizing the protocol model instantiation. Based on the analytical results, we propose the physicalratioK (PRK) interference model as a reliabilityoriented instantiation of the protocol model. Via analysis, simulation, and testbedbased measurement, we show that PRKbased scheduling achieves a network throughput very close to (e.g., 95%) what is enabled by physicalmodelbased scheduling while ensuring the required packet delivery reliability. The PRK model inherits both the high fidelity of the physical model and the locality of the protocol model, thus it is expected to be suitable for distributed protocol design. These findings shed new light on wireless interference models; they also suggest new approaches to MAC protocol design in the presence of uncertainties in traffic patterns and application QoS requirements.
other authors
 Biocontrol Sci Technol
, 1999
"... Differential effects of salen and manganesesalen complex (EUK8) on the regulation of cellular cadmium uptake and toxicity ..."
Abstract

Cited by 8 (1 self)
 Add to MetaCart
(Show Context)
Differential effects of salen and manganesesalen complex (EUK8) on the regulation of cellular cadmium uptake and toxicity
Joint Resource Allocation and Admission Control in Wireless Mesh Networks
"... Many next generation applications (such as video flows) are likely to have associated minimum data rate requirements to ensure satisfactory quality as perceived by endusers. While there have been prior approaches on supporting qualityofservice (QoS) in mesh networks, they have largely ignored th ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
Many next generation applications (such as video flows) are likely to have associated minimum data rate requirements to ensure satisfactory quality as perceived by endusers. While there have been prior approaches on supporting qualityofservice (QoS) in mesh networks, they have largely ignored the issues that arise due to selfinterference, the interference between different link layer transmissions of a single flow along a multihop path. In this paper, we develop a framework to address the problem of maximizing the aggregate utility of traffic flows in wireless mesh networks, with constraints imposed both due to selfinterference and minimum rate requirements. The output of our framework is a schedule that dictates which links are to be activated simultaneously, and provides specifications of the resources associated with each of those links. Utilizing the proposed framework as a basis, we build an admission control module that intelligently manages the resources among the flows in the network and admits as many new flows as possible without violating the QoS of the existing flows. We provide numerical results to demonstrate the efficacy of our framework.
1A Class of CrossLayer Optimization Algorithms for Performance and Complexity Tradeoffs in Wireless Networks
"... Abstract—In this paper, we solve the problem of a joint optimal design of congestion control and wireless MAClayer scheduling using a column generation approach with imperfect scheduling. We point out that the general subgradient algorithm has difficulty in recovering the timeshare variables and e ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
(Show Context)
Abstract—In this paper, we solve the problem of a joint optimal design of congestion control and wireless MAClayer scheduling using a column generation approach with imperfect scheduling. We point out that the general subgradient algorithm has difficulty in recovering the timeshare variables and experiences slower convergence. We first propose a twotimescale algorithm that can recover the optimal timeshare values. Most existing algorithms have a component, called global scheduling, which is usually NPhard. We apply imperfect scheduling and prove that if the imperfect scheduling achieves an approximation ratio ρ, then our algorithm converges to a suboptimum of the overall problem with the same approximation ratio. By combining the idea of column generation and the twotimescale algorithm, we derive a family of algorithms that allow us to reduce the number of times the global scheduling is needed.