Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291571
S. T. Aditya, P. Manohar, D. Manjunath
We consider k-coverage of a line by a twodimensional, non homogeneous Poisson-Boolean model. This has applications in sensor networks. We extend the analysis of [1] to the case for k ≫ 1. The extension requires us to define a vector Markov process that tracks the k segments that have the longest residual coverage at a point. This process is used to determine the probability of a segment of the line being completely covered by k or more sensors. We illustrate the extension by considering the case of k = 2.
{"title":"On the k-coverage of line segments by a non homogeneous Poisson-Boolean model","authors":"S. T. Aditya, P. Manohar, D. Manjunath","doi":"10.1109/WIOPT.2009.5291571","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291571","url":null,"abstract":"We consider k-coverage of a line by a twodimensional, non homogeneous Poisson-Boolean model. This has applications in sensor networks. We extend the analysis of [1] to the case for k ≫ 1. The extension requires us to define a vector Markov process that tracks the k segments that have the longest residual coverage at a point. This process is used to determine the probability of a segment of the line being completely covered by k or more sensors. We illustrate the extension by considering the case of k = 2.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"545 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123377579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291588
A. Giovanidis, S. Stańczak
In the current work the effects of hop-by-hop packet loss and retransmissions via ARQ protocols are investigated within a Mobile Ad-hoc NET-work (MANET). Errors occur due to outages and a success probability function is related to each link, which can be controlled by power and rate allocation. We first derive the expression for the network's capacity region. A Network Utility Maximization problem (NUM) with stability constraints is further formulated which decomposes into (a) the input rate control problem and (b) the scheduling problem. The NUM problem can be solved in a fully decentralized manner if (b) is solved distributedly. Use of supermodular game theory suggests a price based algorithm that requires minimum information exchange between interfering nodes and converges to a power allocation which satisfies the necessary optimality conditions of (b). Simulations illustrate that the suggested algorithm brings near optimal results.
{"title":"Retransmission aware congestion control and distributed power allocation in MANETs","authors":"A. Giovanidis, S. Stańczak","doi":"10.1109/WIOPT.2009.5291588","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291588","url":null,"abstract":"In the current work the effects of hop-by-hop packet loss and retransmissions via ARQ protocols are investigated within a Mobile Ad-hoc NET-work (MANET). Errors occur due to outages and a success probability function is related to each link, which can be controlled by power and rate allocation. We first derive the expression for the network's capacity region. A Network Utility Maximization problem (NUM) with stability constraints is further formulated which decomposes into (a) the input rate control problem and (b) the scheduling problem. The NUM problem can be solved in a fully decentralized manner if (b) is solved distributedly. Use of supermodular game theory suggests a price based algorithm that requires minimum information exchange between interfering nodes and converges to a power allocation which satisfies the necessary optimality conditions of (b). Simulations illustrate that the suggested algorithm brings near optimal results.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133083914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291641
Haibo Zhang, Pablo Soldati, M. Johansson
Convergecast, in which data from a set of sources is routed toward one data sink, is a critical functionality for wireless networks deployed for industrial monitoring and control. We address the joint link scheduling and channel assignment problem for convergecast in networks operating according to the recent WirelessHART standard. For a linear network with N single-buffer devices, we demonstrate that the minimum time to complete convergecast is 2N-1 time-slots, and that the minimum number of channels required for this operation is ⌈N/2⌉. When the devices are allowed to buffer multiple packets, we prove that the optimal convergecast time remains the same while the number of required channels can be reduced to . For both cases, we present jointly time- and channel-optimal scheduling policies with complexity O(N2). Numerical results demonstrate that our schemes are also efficient in terms of memory utilization.
{"title":"Optimal link scheduling and channel assignment for convergecast in linear WirelessHART networks","authors":"Haibo Zhang, Pablo Soldati, M. Johansson","doi":"10.1109/WIOPT.2009.5291641","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291641","url":null,"abstract":"Convergecast, in which data from a set of sources is routed toward one data sink, is a critical functionality for wireless networks deployed for industrial monitoring and control. We address the joint link scheduling and channel assignment problem for convergecast in networks operating according to the recent WirelessHART standard. For a linear network with N single-buffer devices, we demonstrate that the minimum time to complete convergecast is 2N-1 time-slots, and that the minimum number of channels required for this operation is ⌈N/2⌉. When the devices are allowed to buffer multiple packets, we prove that the optimal convergecast time remains the same while the number of required channels can be reduced to . For both cases, we present jointly time- and channel-optimal scheduling policies with complexity O(N2). Numerical results demonstrate that our schemes are also efficient in terms of memory utilization.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132334272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291621
K. Pelechrinis, Christos Koufogiannakis, S. Krishnamurthy
Frequency hopping has been the most popularly considered approach for alleviating the effects of jamming attacks. In this paper, we provide a novel, measurement-driven, game theoretic framework that captures the interactions between a communication link and an adversarial jammer, possibly with multiple jamming devices, in a wireless network employing frequency hopping (FH). The framework can be used to quantify the efficacy of FH as a jamming countermeasure. Our model accounts for two important factors that affect the aforementioned interactions: (a) the number of orthogonal channels available for use and (b) the frequency separation between these orthogonal bands. If the latter is small, then the energy spill over between two adjacent channels (considered orthogonal) is high; as a result a jammer on an orthogonal band that is adjacent to that used by a legitimate communication, can be extremely effective. We account for both these factors and using our framework we provide bounds on the performance of proactive frequency hopping in alleviating the impact of a jammer. The main contributions of our work are: (a) Construction of a measurement driven game theoretic framework which models the interactions between a jammer and a communication link that employ FH. (b) Extensive experimentation on our indoor testbed in order to quantify the impact of a jammer in a 802.11a/g network. (c) Application of our framework to quantify the efficacy of proactive FH across a variety of 802.11 network configurations. (d) Formal derivation of the optimal strategies for both the link and the jammer in 802.11 networks. Our results demonstrate that frequency hopping is largely inadequate in coping with jamming attacks in current 802.11 networks. In particular, we show that if current systems were to support hundreds of additional channels, FH would form a robust jamming countermeasure1.
{"title":"Gaming the jammer: Is frequency hopping effective?","authors":"K. Pelechrinis, Christos Koufogiannakis, S. Krishnamurthy","doi":"10.1109/WIOPT.2009.5291621","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291621","url":null,"abstract":"Frequency hopping has been the most popularly considered approach for alleviating the effects of jamming attacks. In this paper, we provide a novel, measurement-driven, game theoretic framework that captures the interactions between a communication link and an adversarial jammer, possibly with multiple jamming devices, in a wireless network employing frequency hopping (FH). The framework can be used to quantify the efficacy of FH as a jamming countermeasure. Our model accounts for two important factors that affect the aforementioned interactions: (a) the number of orthogonal channels available for use and (b) the frequency separation between these orthogonal bands. If the latter is small, then the energy spill over between two adjacent channels (considered orthogonal) is high; as a result a jammer on an orthogonal band that is adjacent to that used by a legitimate communication, can be extremely effective. We account for both these factors and using our framework we provide bounds on the performance of proactive frequency hopping in alleviating the impact of a jammer. The main contributions of our work are: (a) Construction of a measurement driven game theoretic framework which models the interactions between a jammer and a communication link that employ FH. (b) Extensive experimentation on our indoor testbed in order to quantify the impact of a jammer in a 802.11a/g network. (c) Application of our framework to quantify the efficacy of proactive FH across a variety of 802.11 network configurations. (d) Formal derivation of the optimal strategies for both the link and the jammer in 802.11 networks. Our results demonstrate that frequency hopping is largely inadequate in coping with jamming attacks in current 802.11 networks. In particular, we show that if current systems were to support hundreds of additional channels, FH would form a robust jamming countermeasure1.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115721089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291637
Honghai Zhang, S. Rangarajan
We consider the problem of maximizing the weighted sum data rate in multi-cell and multi-carrier wireless data systems in the presence of interference. We present a scheme that jointly considers load balancing, user scheduling, and interference mitigation to improve the system performance. Our proposed scheme iteratively applies two processes. The first process solves the sub-problem of load balancing and user scheduling while fixing the power allocation of each BS (and thus fixing the interference). We prove that this sub-problem is NP-hard, and devise a 1/2-approximation algorithm to solve the problem. We also consider an extended model capturing finite queue size and propose a 1/2-approximation algorithm under this model. The second process solves the problem of interference mitigation assuming fixed load balancing and user scheduling. We develop a local-improvement based algorithm to solve this problem. Via simulations, we demonstrate that our joint scheme improves both average system throughput and fairness significantly. Compared to the scheme with fixed user-BS association and 1/3 frequency reuse, the lowest 10% cell-edge users obtain more than 60% performance improvement and 90%of users enjoy more than 30%throughput improvement.
{"title":"Joint load balancing, scheduling, and interference mitigation in multi-cell and multi-carrier wireless data systems","authors":"Honghai Zhang, S. Rangarajan","doi":"10.1109/WIOPT.2009.5291637","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291637","url":null,"abstract":"We consider the problem of maximizing the weighted sum data rate in multi-cell and multi-carrier wireless data systems in the presence of interference. We present a scheme that jointly considers load balancing, user scheduling, and interference mitigation to improve the system performance. Our proposed scheme iteratively applies two processes. The first process solves the sub-problem of load balancing and user scheduling while fixing the power allocation of each BS (and thus fixing the interference). We prove that this sub-problem is NP-hard, and devise a 1/2-approximation algorithm to solve the problem. We also consider an extended model capturing finite queue size and propose a 1/2-approximation algorithm under this model. The second process solves the problem of interference mitigation assuming fixed load balancing and user scheduling. We develop a local-improvement based algorithm to solve this problem. Via simulations, we demonstrate that our joint scheme improves both average system throughput and fairness significantly. Compared to the scheme with fixed user-BS association and 1/3 frequency reuse, the lowest 10% cell-edge users obtain more than 60% performance improvement and 90%of users enjoy more than 30%throughput improvement.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114222408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291631
Wen Wang, L. Ong, M. Motani
Half duplex devices are widely used in today's wireless networks. These devices can only send or receive, but not do both at the same time. In this paper, we use cooperative decode-forward relay strategies to increase the throughput of half-duplex wireless networks. Due to the half duplex constraint, relays need to carefully choose their transmission states in order to maximize the throughput. We show that the transmission schedule optimization can be formulated as a linear programming problem. Although the number of possible states grows exponentially as the number of relays increases, only a small subset of these states needs to be used in the optimal transmission schedule. This observation allows us to use heuristic algorithms to solve for near-optimal schedule in large networks. Our numerical results show that the decode-forward strategy can provide nearly 3 times more throughput than the traditional multi-hop relaying strategy in half duplex wireless networks.
{"title":"Transmission schedule optimization for half-duplex multiple-relay networks","authors":"Wen Wang, L. Ong, M. Motani","doi":"10.1109/WIOPT.2009.5291631","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291631","url":null,"abstract":"Half duplex devices are widely used in today's wireless networks. These devices can only send or receive, but not do both at the same time. In this paper, we use cooperative decode-forward relay strategies to increase the throughput of half-duplex wireless networks. Due to the half duplex constraint, relays need to carefully choose their transmission states in order to maximize the throughput. We show that the transmission schedule optimization can be formulated as a linear programming problem. Although the number of possible states grows exponentially as the number of relays increases, only a small subset of these states needs to be used in the optimal transmission schedule. This observation allows us to use heuristic algorithms to solve for near-optimal schedule in large networks. Our numerical results show that the decode-forward strategy can provide nearly 3 times more throughput than the traditional multi-hop relaying strategy in half duplex wireless networks.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114263092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291616
Xusheng Sun, E. Coyle
In clustered networks of wireless sensor motes, each mote collects noisy observations of the environment, quantizes these observations into a local estimate of finite length, and forwards them through one or more noisy wireless channels to the Cluster Head (CH). The measurement noise is assumed to be zero-mean and have finite variance. Each wireless hop is assumed to be a Binary Symmetric Channel (BSC) with a known crossover probability. We propose a novel scheme that uses dithered quantization and channel compensation to ensure that each motes' local estimate received by the CH is unbiased. The CH then fuses these unbiased local estimates into a global one using a Best Linear Unbiased Estimator (BLUE). The energy allocation problem at each mote and among different sensor motes are also discussed. Simulation results show that the proposed scheme can achieve much smaller mean square error (MSE) than two other common schemes while using the same amount of energy. The sensitivity of the proposed scheme to errors in estimates of the crossover probability of the BSC channel is studied by both analysis and simulation.
{"title":"Quantization, channel compensation, and energy allocation for estimation in wireless sensor networks","authors":"Xusheng Sun, E. Coyle","doi":"10.1109/WIOPT.2009.5291616","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291616","url":null,"abstract":"In clustered networks of wireless sensor motes, each mote collects noisy observations of the environment, quantizes these observations into a local estimate of finite length, and forwards them through one or more noisy wireless channels to the Cluster Head (CH). The measurement noise is assumed to be zero-mean and have finite variance. Each wireless hop is assumed to be a Binary Symmetric Channel (BSC) with a known crossover probability. We propose a novel scheme that uses dithered quantization and channel compensation to ensure that each motes' local estimate received by the CH is unbiased. The CH then fuses these unbiased local estimates into a global one using a Best Linear Unbiased Estimator (BLUE). The energy allocation problem at each mote and among different sensor motes are also discussed. Simulation results show that the proposed scheme can achieve much smaller mean square error (MSE) than two other common schemes while using the same amount of energy. The sensitivity of the proposed scheme to errors in estimates of the crossover probability of the BSC channel is studied by both analysis and simulation.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114279324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291601
P. Simoens, B. Vankeirsbilck, F. Ali, L. Deboosere, F. Turck, B. Dhoedt, P. Demeester, R. T. Duran, C. Desset
In thin client computing, applications are executed on a network server instead of on the user terminal. Since the amount of processing at the terminal is reduced, thin clients are potentially energy efficient devices. However, a network connection between client and server is required for the transmission of user input and display updates. The energy needed for this intense network communication might undo or even exceed the power savings achieved by the reduction in client-side processing. In this paper, we present experimental results on power efficiency of the wireless platform on the thin client in case of thin client traffic. The discussion is focused on VNC-RFB, a widespread thin client protocol, over an IEEE 802.11 link in three typical user scenarios. The results indicate that a cross-layer approach between application and wireless link layer could potentially lead to important power savings.
{"title":"Characterization of power consumption in thin clients due to protocol data transmission over IEEE 802.11","authors":"P. Simoens, B. Vankeirsbilck, F. Ali, L. Deboosere, F. Turck, B. Dhoedt, P. Demeester, R. T. Duran, C. Desset","doi":"10.1109/WIOPT.2009.5291601","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291601","url":null,"abstract":"In thin client computing, applications are executed on a network server instead of on the user terminal. Since the amount of processing at the terminal is reduced, thin clients are potentially energy efficient devices. However, a network connection between client and server is required for the transmission of user input and display updates. The energy needed for this intense network communication might undo or even exceed the power savings achieved by the reduction in client-side processing. In this paper, we present experimental results on power efficiency of the wireless platform on the thin client in case of thin client traffic. The discussion is focused on VNC-RFB, a widespread thin client protocol, over an IEEE 802.11 link in three typical user scenarios. The results indicate that a cross-layer approach between application and wireless link layer could potentially lead to important power savings.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114475696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291590
Sara Akbarzadeh, L. Cottatellucci, C. Bonnet
We considered a dense interference network with a large number (K → ∞) of transmitter-receiver pairs. Each transmitter is endowed with a finite buffer and accepts packets from an arrival process. Each transmitter-receiver link is a fading vector channel with N diversity paths whose statistics are described by a Markov chain. We investigate distributed algorithms for joint admission control, rate and power allocation aiming at maximizing the individual throughput defined as the average information rate successfully received. The decisions are based on the statistical knowledge of the channel and buffer states of the other communication pairs and on the exact knowledge of their own channel and buffer states. In the case of a finite number of communication pairs this problem is computationally extremely intensive with an exponential complexity in the number of users. Assuming that K,N → ∞ with constant ratio the algorithm complexity becomes substantially independent of the number of active communications and grows with the groups of users having distinct asymptotic channel statistics. The cross-layer design is investigated for different kind of decoders at the receiver. The benefits of a cross layer approach compared to a resource allocation ignoring the states of the queues are assessed. The performance loss due to the use of policies designed for asymptotic conditions and applied to networks with a finite number of active communications is studied.
{"title":"Low complexity cross-layer design for dense interference networks","authors":"Sara Akbarzadeh, L. Cottatellucci, C. Bonnet","doi":"10.1109/WIOPT.2009.5291590","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291590","url":null,"abstract":"We considered a dense interference network with a large number (K → ∞) of transmitter-receiver pairs. Each transmitter is endowed with a finite buffer and accepts packets from an arrival process. Each transmitter-receiver link is a fading vector channel with N diversity paths whose statistics are described by a Markov chain. We investigate distributed algorithms for joint admission control, rate and power allocation aiming at maximizing the individual throughput defined as the average information rate successfully received. The decisions are based on the statistical knowledge of the channel and buffer states of the other communication pairs and on the exact knowledge of their own channel and buffer states. In the case of a finite number of communication pairs this problem is computationally extremely intensive with an exponential complexity in the number of users. Assuming that K,N → ∞ with constant ratio the algorithm complexity becomes substantially independent of the number of active communications and grows with the groups of users having distinct asymptotic channel statistics. The cross-layer design is investigated for different kind of decoders at the receiver. The benefits of a cross layer approach compared to a resource allocation ignoring the states of the queues are assessed. The performance loss due to the use of policies designed for asymptotic conditions and applied to networks with a finite number of active communications is studied.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"163 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129281679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-23DOI: 10.1109/WIOPT.2009.5291593
C. Yeung, K. Y. Wong
We study a model of transportation networks with nonlinear elements which represent local shortage of resources. Frustration arises from competition among the nodes to become satisfied. When the initial resources are uniform, algorithmically hard regimes emerge when the average availability of resources increases. These regimes are characterized by discrete fractions of satisfied nodes, resembling the Devil's staircase. Behavior similar to those in the vertex cover or close packing problems are found. When initial resources are bimodally distributed, such algorithmically hard regimes also emerge when the fraction of rich nodes increases.
{"title":"Emergence of algorithmically hard phases in transportation networks","authors":"C. Yeung, K. Y. Wong","doi":"10.1109/WIOPT.2009.5291593","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291593","url":null,"abstract":"We study a model of transportation networks with nonlinear elements which represent local shortage of resources. Frustration arises from competition among the nodes to become satisfied. When the initial resources are uniform, algorithmically hard regimes emerge when the average availability of resources increases. These regimes are characterized by discrete fractions of satisfied nodes, resembling the Devil's staircase. Behavior similar to those in the vertex cover or close packing problems are found. When initial resources are bimodally distributed, such algorithmically hard regimes also emerge when the fraction of rich nodes increases.","PeriodicalId":143632,"journal":{"name":"2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130940234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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