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Delay analysis for multihop wireless networks
 IEEE INFOCOM
, 2009
"... Abstract—We analyze the delay performance of a multihop wireless network with a fixed route between each sourcedestination pair. There are arbitrary interference constraints on the set of links that can be served simultaneously at any given time. These interference constraints impose a fundamental l ..."
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Abstract—We analyze the delay performance of a multihop wireless network with a fixed route between each sourcedestination pair. There are arbitrary interference constraints on the set of links that can be served simultaneously at any given time. These interference constraints impose a fundamental lower bound on the delay performance of any scheduling policy for the system. We present a methodology to derive such lower bounds. For the tandem queue network, where the delay optimal policy is known, the expected delay of the optimal policy numerically coincides with the lower bound. We conduct extensive numerical studies to suggest that the average delay of the backpressure scheduling policy can be made close to the lower bound by using appropriate functions of queue length. I.
Delay Analysis and Optimality of Scheduling Policies for MultiHop Wireless Networks
"... In this paper, we analyze the delay performance of a multihop wireless network in which the routes between sourcedestination pairs are fixed. We develop a new queue grouping technique to handle the complex correlations of the service process resulting from the multihop nature of the flows and th ..."
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Cited by 8 (1 self)
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In this paper, we analyze the delay performance of a multihop wireless network in which the routes between sourcedestination pairs are fixed. We develop a new queue grouping technique to handle the complex correlations of the service process resulting from the multihop nature of the flows and their mutual sharing of the wireless medium. A general setbased interference model is assumed that imposes constraints on links that can be served simultaneously at any given time. These interference constraints are used to obtain a fundamental lower bound on the delay performance of any scheduling policy for the system. We present a systematic methodology to derive such lower bounds. For a special wireless system, namely the clique, we design a policy that is sample path delay optimal. For the tandem queue network, where the delay optimal policy is known, the expected delay of the optimal policy numerically coincides with the lower bound. The lower bound analysis provides useful insights into the design and analysis of optimal or nearly optimal scheduling policies. We conduct extensive numerical studies to demonstrate that one can design policies whose average delay performance is close to the lower bound computed by the techniques presented in this paper.
Delay Efficient Scheduling via Redundant Constraints in Multihop Networks
, 2010
"... Abstract—We consider the problem of delayefficient scheduling in general multihop networks. While the class of maxweight type algorithms are known to be throughput optimal for this problem, they typically incur undesired delay performance. In this paper, we propose the DelayEfficient SCheduling a ..."
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Abstract—We consider the problem of delayefficient scheduling in general multihop networks. While the class of maxweight type algorithms are known to be throughput optimal for this problem, they typically incur undesired delay performance. In this paper, we propose the DelayEfficient SCheduling algorithm (DESC). DESC is built upon the idea of accelerating queues (AQ), which are virtual queues that quickly propagate the traffic arrival information along the routing paths. DESC is motivated by the use of redundant constraints to accelerate convergence in the classic optimization context. We show that DESC is throughputoptimal. The delay bound of DESC can be better than previous bounds of the maxweight type algorithms which did not use such traffic information. We also show that under DESC, the service rates allocated to the flows converge quickly to their target values and the average total “network service lag ” is small. In particular, when there are O(1) flows and the rate vector is of Θ(1) distance away from the boundary of the capacity region, the average total “service lag ” only grows linearly in the network size.
Delay Minimization in Multihop Wireless Networks: Static Scheduling Does It
"... Abstract—In this paper, we address two issues in multihop wireless networks—poor endtoend delay performance and high perslot computational overhead of the classical maxweight algorithm. To reduce the endtoend delay, we first propose a simple modification to the classical maximum weight schedul ..."
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Abstract—In this paper, we address two issues in multihop wireless networks—poor endtoend delay performance and high perslot computational overhead of the classical maxweight algorithm. To reduce the endtoend delay, we first propose a simple modification to the classical maximum weight scheduling algorithm that promotes the use of shorter paths by the packets. The significantly lower delays are shown via simulation. The modification that we suggest does not reduce the schedulable region and has the same complexity as the classical algorithm. Next, we propose a static routing and scheduling scheme that is obtained by adapting the classical optimal routing problem of wireline networks to multihop wireless networks. The static scheme slows the timescale of routing and scheduling computations from perslot to the timescale of change in the network traffic pattern; thus the computation complexity is reduced. We also show, via simulations, that the delay performance in the static scheme is comparable to that of the dynamic scheme that we have proposed. I.
ARCHITECTURE FOR ENSURING SECURITY REQUIRMENTS IN WIRELESS MESH NETWORKS
"... Anonymity has received increasing attention in the literature due to the users ’ awareness of their privacy nowadays. Anonymity provides protection for users to enjoy network services without being traced. While anonymityrelated issues have been extensively studied in paymentbased systems such as ..."
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Anonymity has received increasing attention in the literature due to the users ’ awareness of their privacy nowadays. Anonymity provides protection for users to enjoy network services without being traced. While anonymityrelated issues have been extensively studied in paymentbased systems such as ecash and peertopeer (P2P) systems, little effort has been devoted to wireless mesh networks (WMNs). On the other hand, the network authority requires conditional anonymity such that misbehaving entities in the network remain traceable. Here, we propose a security architecture to ensure unconditional anonymity for honest users and traceability of misbehaving users for network authorities in WMNs. [1]The proposed architecture strives to resolve the conflicts between the anonymity and traceability objectives, in addition to guaranteeing fundamental security requirements including authentication, confidentiality, data integrity, and no repudiation. Thorough analysis on security and efficiency is incorporated, demonstrating the feasibility and effectiveness of the proposed architecture.
Optimizing Scheduling Policies and Analyzing Delay in MultiHop Wireless Networks
"... Abstract: In this paper a multihop wireless network is considered to analyze the delay performance. We assume that there is a fixed route between a given source and destination pair. The multihop nature of network may cause complex correlations of the service process. In order to handle them, we p ..."
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Abstract: In this paper a multihop wireless network is considered to analyze the delay performance. We assume that there is a fixed route between a given source and destination pair. The multihop nature of network may cause complex correlations of the service process. In order to handle them, we propose a queue grouping technique. An interference model is assumed which is set based. With the help of interference constraints the lower bound of delay performance is obtained. To achieve this systematic methodology is used. The simplepath delayoptimal policy we designed is used for wireless networks. Empirical studies revealed that our approach is good to optimize scheduling policies and analyzing delay in multihop wireless networks.
1 Approximation Algorithms for Throughput Maximization in Wireless Networks with Delay Constraints
"... Abstract—We study the problem of throughput maximization in multihop wireless networks with endtoend delay constraints for each session. This problem has received much attention starting with the work of Grossglauser and Tse (2002), and it has been shown that there is a significant tradeoff betw ..."
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Abstract—We study the problem of throughput maximization in multihop wireless networks with endtoend delay constraints for each session. This problem has received much attention starting with the work of Grossglauser and Tse (2002), and it has been shown that there is a significant tradeoff between the endtoend delays and the total achievable rate. We develop algorithms to compute such tradeoffs with provable performance guarantees for arbitrary instances, with general interference models. Given a target delaybound ∆(c) for each session c, our algorithm gives a stable flow vector with a total throughput within a factor of O () log∆m of the maximum, so that the loglog∆m persession (endtoend) delay is O ( ( log∆m loglog∆m ∆(c))2) , where ∆m = maxc{∆(c)}; note that these bounds depend only on the delays, and not on the network size, and this is the first such result, to our knowledge.
THEORY FOR DISTRIBUTED REALTIME SYSTEMS BY
"... develops a new reductionbased analysis methodology for studying the worstcase endtoend delay and schedulability of realtime jobs in distributed systems. The main result is a simple delay composition rule, that computes a worstcase bound on the endtoend delay of a job, given the computation t ..."
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develops a new reductionbased analysis methodology for studying the worstcase endtoend delay and schedulability of realtime jobs in distributed systems. The main result is a simple delay composition rule, that computes a worstcase bound on the endtoend delay of a job, given the computation times of all other jobs that execute concurrently with it in the system. This delay composition rule is first derived for pipelined distributed systems, where all the jobs execute on the same sequence of resources before leaving the system. We then derive the delay composition rule for systems where the union of task paths forms a Directed Acyclic Graph (DAG), and subsequently generalize the result to nonacyclic task graphs as well, under both preemptive and nonpreemptive scheduling. The result makes no assumptions on periodicity and is valid for periodic and aperiodic jobs. It applies to fixed and dynamic priority scheduling, as long as all jobs have the same relative priority on all stages on which they execute. The delay composition result enables a simple reduction of the distributed system to an equivalent hypothetical uniprocessor that can be analyzed using traditional uniprocessor schedulability analysis to infer the schedulability of the distributed system. Thus, the wealth of uniprocessor analysis techniques can now be used to analyze distributed task systems. Such a reduction significantly reduces the complexity of analysis and ensures that the analysis does not become exceedingly pessimistic with system scale, unlike existing analysis techniques for distributed systems