This work seeks to develop an analytical model for the per-node throughput analysis of IEEE 802.11 WLAN networks with hidden nodes by extending the Bianchi's model. With the analytic model we derive the per-node throughput of each node and quantify the impact of hidden nodes on per-node throughput. Through our analysis, we find that nodes having more hidden nodes are likely to have worse throughput performance than nodes having less hidden nodes, so resulting in unfairness in per-node throughput. We next propose a new algorithm, called the fake collision algorithm, to solve the unfairness due to hidden nodes. The proposed fake collision algorithm allows nodes with poor throughput to acquire more transmission opportunities by slightly modifying the Binary Exponential Backoff algorithm of the IEEE 802.11 Distributed Coordination Function. To this end, the fake collision algorithm uses a new control parameter called the fake collision probability which can be obtained from a computation algorithm that we develop based on our analytic model. We show that the fairness in per-node throughput can be achieved with the fake collision probability for each node through simulation.
{"title":"Performance modeling and analysis of IEEE 802.11 wireless networks with hidden nodes","authors":"M. Lee, G. Hwang, Sumit Roy","doi":"10.1145/2507924.2507947","DOIUrl":"https://doi.org/10.1145/2507924.2507947","url":null,"abstract":"This work seeks to develop an analytical model for the per-node throughput analysis of IEEE 802.11 WLAN networks with hidden nodes by extending the Bianchi's model. With the analytic model we derive the per-node throughput of each node and quantify the impact of hidden nodes on per-node throughput. Through our analysis, we find that nodes having more hidden nodes are likely to have worse throughput performance than nodes having less hidden nodes, so resulting in unfairness in per-node throughput. We next propose a new algorithm, called the fake collision algorithm, to solve the unfairness due to hidden nodes. The proposed fake collision algorithm allows nodes with poor throughput to acquire more transmission opportunities by slightly modifying the Binary Exponential Backoff algorithm of the IEEE 802.11 Distributed Coordination Function. To this end, the fake collision algorithm uses a new control parameter called the fake collision probability which can be obtained from a computation algorithm that we develop based on our analytic model. We show that the fairness in per-node throughput can be achieved with the fake collision probability for each node through simulation.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114680015","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}
J. Oller, I. Demirkol, J. Casademont, J. Aspas, G. U. Gamm, L. Reindl
The use of duty-cycling in Medium Access Control (MAC) protocols effectively helps improving the energy efficiency of wireless networks. However, while the benefits of these protocols are unquestionable, most of them still suffer from overhearing and idle listening, two issues that prevent duty-cycled systems from achieving optimum energy usage, which is a crucial aspect in specific types of wireless networks such as Wireless Sensor Networks (WSN).Wake-up Radio (WuR) systems have been employed recently to overcome these issues. Under this approach, the nodes' MicroController Unit (MCU) and main radio transceiver are completely switched off and only activated when a secondary, extremely low-power receiver in the node is triggered by a particular wireless transmission. Wake-up Radio systems allow for drastic energy savings since receiver nodes are only activated on-demand, maximizing their battery lifetimes. In this paper, we have modeled and simulated a real, recent and promising WuR hardware platform based on its time and energy consumption characterization. By comparing such WuR approach to B-MAC and IEEE 802.15.4, two well-known and widely employed MAC protocols, we show it effectively out-performs the conventional WSN MAC approaches in terms of energy efficiency. To the best of authors' knowledge, this is the first study to include a comparative analysis for multi-hop networks based on a real WuR platform, which shows WuR systems represent an energy-efficient solution that also provides a good tradeoff between latency, packet delivery ratio and applicability..
{"title":"Wake-up radio as an energy-efficient alternative to conventional wireless sensor networks MAC protocols","authors":"J. Oller, I. Demirkol, J. Casademont, J. Aspas, G. U. Gamm, L. Reindl","doi":"10.1145/2507924.2507955","DOIUrl":"https://doi.org/10.1145/2507924.2507955","url":null,"abstract":"The use of duty-cycling in Medium Access Control (MAC) protocols effectively helps improving the energy efficiency of wireless networks. However, while the benefits of these protocols are unquestionable, most of them still suffer from overhearing and idle listening, two issues that prevent duty-cycled systems from achieving optimum energy usage, which is a crucial aspect in specific types of wireless networks such as Wireless Sensor Networks (WSN).Wake-up Radio (WuR) systems have been employed recently to overcome these issues. Under this approach, the nodes' MicroController Unit (MCU) and main radio transceiver are completely switched off and only activated when a secondary, extremely low-power receiver in the node is triggered by a particular wireless transmission. Wake-up Radio systems allow for drastic energy savings since receiver nodes are only activated on-demand, maximizing their battery lifetimes. In this paper, we have modeled and simulated a real, recent and promising WuR hardware platform based on its time and energy consumption characterization. By comparing such WuR approach to B-MAC and IEEE 802.15.4, two well-known and widely employed MAC protocols, we show it effectively out-performs the conventional WSN MAC approaches in terms of energy efficiency. To the best of authors' knowledge, this is the first study to include a comparative analysis for multi-hop networks based on a real WuR platform, which shows WuR systems represent an energy-efficient solution that also provides a good tradeoff between latency, packet delivery ratio and applicability..","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128478026","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}
The development of IPv6 stacks for wireless constrained devices that have limited hardware resources has paved the way for many new areas of applications and protocols. The Constrained Application Protocol (CoAP) has been designed by the IETF to enable the manipulation of resources for constrained devices that are capable of connecting to the Internet. Due to the limited radio channel capacities and hardware resources, congestion is a common phenomenon in networks of constrained devices. CoAP implements a basic congestion control mechanism for the transmission of reliable messages. Alternative CoAP congestion control approaches are a recent topic of interest in the IETF CoRE Working Group. New Internet-Drafts discuss the limitations of the default congestion control mechanisms and propose alternative ones, yet, there have been no studies in the literature that compare the original approach to the alternative ones. In this paper, we target this crucial study and perform evaluations that show how the default and alternative congestion control mechanisms compare to each other. We use the Cooja simulation environment, which is part of the Contiki development toolset, to simulate CoAP within a complete protocol stack that uses IETF protocols for constrained networks. Through simulations of different network topologies and varying traffic loads, we demonstrate how the advanced mechanisms proposed in the drafts perform relative to the basic congestion control mechanism.
{"title":"Congestion control in reliable CoAP communication","authors":"A. Betzler, Carles Gomez, I. Demirkol, J. Aspas","doi":"10.1145/2507924.2507954","DOIUrl":"https://doi.org/10.1145/2507924.2507954","url":null,"abstract":"The development of IPv6 stacks for wireless constrained devices that have limited hardware resources has paved the way for many new areas of applications and protocols. The Constrained Application Protocol (CoAP) has been designed by the IETF to enable the manipulation of resources for constrained devices that are capable of connecting to the Internet. Due to the limited radio channel capacities and hardware resources, congestion is a common phenomenon in networks of constrained devices. CoAP implements a basic congestion control mechanism for the transmission of reliable messages. Alternative CoAP congestion control approaches are a recent topic of interest in the IETF CoRE Working Group. New Internet-Drafts discuss the limitations of the default congestion control mechanisms and propose alternative ones, yet, there have been no studies in the literature that compare the original approach to the alternative ones. In this paper, we target this crucial study and perform evaluations that show how the default and alternative congestion control mechanisms compare to each other. We use the Cooja simulation environment, which is part of the Contiki development toolset, to simulate CoAP within a complete protocol stack that uses IETF protocols for constrained networks. Through simulations of different network topologies and varying traffic loads, we demonstrate how the advanced mechanisms proposed in the drafts perform relative to the basic congestion control mechanism.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126270427","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}
Underwater sensor networks have recently been proposed as a way to observe and to explore the lakes, rivers, seas, and oceans. A challenging issue in these networks is the communication, mainly due to the impairments of the acoustic transmission. Thus, efficient mechanisms to improve the data delivery must be proposed. In this work we present a novel anycast greedy geographic forwarding protocol and two topology control mechanisms. The proposed geo-routing protocol considers the anycast network architecture in the data forwarding process. The proposed centralized topology control (CTC) and distributed topology control (DTC) mechanisms organize the network via depth adjustment of some nodes. The simulation results show that with these mechanisms, the data packet delivery ratio achieves more than 90% even in hard and difficult scenarios of very sparse or very dense networks, the end-to-end delay and energy consumption per delivered packet is reduced.
{"title":"Movement assisted-topology control and geographic routing protocol for underwater sensor networks","authors":"Rodolfo W. L. Coutinho, L. Vieira, A. Loureiro","doi":"10.1145/2507924.2507956","DOIUrl":"https://doi.org/10.1145/2507924.2507956","url":null,"abstract":"Underwater sensor networks have recently been proposed as a way to observe and to explore the lakes, rivers, seas, and oceans. A challenging issue in these networks is the communication, mainly due to the impairments of the acoustic transmission. Thus, efficient mechanisms to improve the data delivery must be proposed. In this work we present a novel anycast greedy geographic forwarding protocol and two topology control mechanisms. The proposed geo-routing protocol considers the anycast network architecture in the data forwarding process. The proposed centralized topology control (CTC) and distributed topology control (DTC) mechanisms organize the network via depth adjustment of some nodes. The simulation results show that with these mechanisms, the data packet delivery ratio achieves more than 90% even in hard and difficult scenarios of very sparse or very dense networks, the end-to-end delay and energy consumption per delivered packet is reduced.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117213844","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}
Kazuma Kaneko, Y. Kawamoto, Hiroki Nishiyama, N. Kato, Shinichi Yamamoto, N. Yoshimura
Recently, since many kinds of wireless devices have been widely used and a large amount of contents is available on the Internet, a network system that provides adequate services anytime and anywhere is required. In this research, we focus on satellite networks using mass storage devices to provide the above mentioned services. In this kind of network, multiple satellites are used to cover the whole surface of the earth, and each satellite is equipped with a mass storage device. By using mass storage devices, the satellite network can manage a high buffer capacity to handle large amounts of data. However, no routing method has been developed for such kind of satellite network that can utilize the storage devices and manage the large amount of data in the network effectively. In this paper, we propose a novel routing scheme for the efficient utilization of the mass storage on satellites to mitigate network congestion. The proposed method is analyzed mathematically. The numerical results validate the effectiveness of our proposed method.
{"title":"An intelligent routing scheme effectively utilizing mass storage embedded on satellites to mitigate network congestions","authors":"Kazuma Kaneko, Y. Kawamoto, Hiroki Nishiyama, N. Kato, Shinichi Yamamoto, N. Yoshimura","doi":"10.1145/2507924.2507951","DOIUrl":"https://doi.org/10.1145/2507924.2507951","url":null,"abstract":"Recently, since many kinds of wireless devices have been widely used and a large amount of contents is available on the Internet, a network system that provides adequate services anytime and anywhere is required. In this research, we focus on satellite networks using mass storage devices to provide the above mentioned services. In this kind of network, multiple satellites are used to cover the whole surface of the earth, and each satellite is equipped with a mass storage device. By using mass storage devices, the satellite network can manage a high buffer capacity to handle large amounts of data. However, no routing method has been developed for such kind of satellite network that can utilize the storage devices and manage the large amount of data in the network effectively. In this paper, we propose a novel routing scheme for the efficient utilization of the mass storage on satellites to mitigate network congestion. The proposed method is analyzed mathematically. The numerical results validate the effectiveness of our proposed method.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115661285","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}
Thiago Abreu, B. Baynat, Thomas Begin, I. G. Lassous
IEEE 802.11 is implemented in many wireless networks, including multi-hop networks where communications between nodes are conveyed along a chain. We present a modeling framework to evaluate the performance of flows conveyed through such a chain. Our framework is based on a hierarchical modeling composed of two levels. The lower level is dedicated to the modeling of each node, while the upper level matches the actual topology of the chain. Our approach can handle different topologies, takes into account Bit Error Rate and can be applied to multi-hop flows with rates ranging from light to heavy workloads. We assess the ability of our model to evaluate loss rate, throughput, and end-to-end delay experienced by flows on a simple scenario, where the number of nodes is limited to three. Numerical results show that our model accurately approximates the performance of flows with a relative error typically less than 10%.
{"title":"Hierarchical modeling of IEEE 802.11 multi-hop wireless networks","authors":"Thiago Abreu, B. Baynat, Thomas Begin, I. G. Lassous","doi":"10.1145/2507924.2507949","DOIUrl":"https://doi.org/10.1145/2507924.2507949","url":null,"abstract":"IEEE 802.11 is implemented in many wireless networks, including multi-hop networks where communications between nodes are conveyed along a chain. We present a modeling framework to evaluate the performance of flows conveyed through such a chain. Our framework is based on a hierarchical modeling composed of two levels. The lower level is dedicated to the modeling of each node, while the upper level matches the actual topology of the chain. Our approach can handle different topologies, takes into account Bit Error Rate and can be applied to multi-hop flows with rates ranging from light to heavy workloads. We assess the ability of our model to evaluate loss rate, throughput, and end-to-end delay experienced by flows on a simple scenario, where the number of nodes is limited to three. Numerical results show that our model accurately approximates the performance of flows with a relative error typically less than 10%.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122901351","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}
In this paper, we consider a distributed opportunistic access (D-OSA), in which cognitive radio (CR) users attempt to access a channel licensed to a primary network. In this context, we formulate the problem of designing the equilibrium sensing time in a distributed manner, in order to maximize the throughput of CR users while guarantying a good protection to the primary users (PU). Next, we study the Nash equilibrium of the system, we also propose a combined learning algorithm for continuous actions that is fully distributed, and allows to the CR users to learn their equilibrium payoffs and their equilibrium sensing time. The simulation results show that the system can learn the sensing time and converge to a unique Nash equilibrium, which come to prove the theoretical study. A surprising feature is that there exists a correlation between the transmit probability and the sensing time. More precisely, lower transmit probability induces lower sensing times.
{"title":"Equilibrium sensing time for distributed opportunistic access incognitive radio networks","authors":"S. Bouferda, Essaid Sabir, A. Hayar, M. Rifi","doi":"10.1145/2507924.2507944","DOIUrl":"https://doi.org/10.1145/2507924.2507944","url":null,"abstract":"In this paper, we consider a distributed opportunistic access (D-OSA), in which cognitive radio (CR) users attempt to access a channel licensed to a primary network. In this context, we formulate the problem of designing the equilibrium sensing time in a distributed manner, in order to maximize the throughput of CR users while guarantying a good protection to the primary users (PU). Next, we study the Nash equilibrium of the system, we also propose a combined learning algorithm for continuous actions that is fully distributed, and allows to the CR users to learn their equilibrium payoffs and their equilibrium sensing time. The simulation results show that the system can learn the sensing time and converge to a unique Nash equilibrium, which come to prove the theoretical study. A surprising feature is that there exists a correlation between the transmit probability and the sensing time. More precisely, lower transmit probability induces lower sensing times.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"16 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113979614","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}
Dynamic base station activation (DBA) has recently emerged as a viable solution for reducing energy consumption in cellular networks. While most of the works on this topic focused on centralized decision making algorithms, in this paper we investigate distributive solutions. These solutions are particularly desirable due to importance of self-organization and self-optimization in future cellular networks. The goal of DBA is to achieve an optimal trade-off between network operator's revenue and operational cost while guaranteeing coverage for network users. The problem is posed as a network utility maximization aiming to find the optimal activation schedule of each base station. Using Lagrangian duality, the problem is decomposed into smaller subproblems, where each subproblem is solved locally at its associated base station. Controlled message passing among base stations ensures convergence to the global optimal solution. Moreover, this general solution is further extended to capture the combinatorial nature of DBA. Finally, numerical results are provided to demonstrate the behavior of our solution in terms of utility and cost trade-off and convergence in some example network scenarios.
{"title":"Distributed base station activation for energy-efficient operation of cellular networks","authors":"A. Abbasi, Majid Ghaderi","doi":"10.1145/2507924.2507961","DOIUrl":"https://doi.org/10.1145/2507924.2507961","url":null,"abstract":"Dynamic base station activation (DBA) has recently emerged as a viable solution for reducing energy consumption in cellular networks. While most of the works on this topic focused on centralized decision making algorithms, in this paper we investigate distributive solutions. These solutions are particularly desirable due to importance of self-organization and self-optimization in future cellular networks. The goal of DBA is to achieve an optimal trade-off between network operator's revenue and operational cost while guaranteeing coverage for network users. The problem is posed as a network utility maximization aiming to find the optimal activation schedule of each base station. Using Lagrangian duality, the problem is decomposed into smaller subproblems, where each subproblem is solved locally at its associated base station. Controlled message passing among base stations ensures convergence to the global optimal solution. Moreover, this general solution is further extended to capture the combinatorial nature of DBA. Finally, numerical results are provided to demonstrate the behavior of our solution in terms of utility and cost trade-off and convergence in some example network scenarios.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116264023","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}
For some time, directional antennas have been considered to solve connectivity and interference issues in wireless networks. Several scenarios have been presented and often the conclusions drawn are positive, showing increase in capacity. However, to date there has been no effort to assess a holistic picture of the benefit/cost tradeoff and previous work mainly concerns either link scheduling or antenna placement but not the two combined. Such consideration will become increasingly important in the near future with the advent of heterogeneous networks and other possible combinations of mesh and public access networks. In order to better understand the full implications and potential of using directional antennas in such systems, we present a model for determining the maximized benefit/cost tradeoff using a combination of directional and omnidirectional antennas in wireless multihop backbones. We study the problem of maximizing the minimal flow rate from gateways to mesh routers in the mesh network. A mixed integer programming model is formulated for joint optimization of antenna placement and link transmission scheduling under an antenna-aware SINR interference constraint and a budget constraint. An accurate antenna model is used and variable modulation and coding schemes are used. The model is decomposed to a master problem and a pricing problem, and solved by a branch-and-price algorithm. Additionally, two effective heuristics are proposed as supplement methods. Applying the introduced model makes it possible to deploy directional antennas at appropriate nodes and find a corresponding link transmission scheduling (with data rate adaptation). The numerical results show that introducing directional antennas can indeed substantially improve the considered traffic objective. Interestingly, the results also show that it is not always optimal to install directional antennas at all possible nodes because of increased interference observed at non-receiving nodes within the beam width. Finally, comparisons are made to show the effectiveness of the proposed solution methods.
{"title":"Improving minimum flow rate in wireless mesh networks by effective placement of directional antennas","authors":"Yuan Li, M. Pióro, B. Landfeldt","doi":"10.1145/2507924.2507933","DOIUrl":"https://doi.org/10.1145/2507924.2507933","url":null,"abstract":"For some time, directional antennas have been considered to solve connectivity and interference issues in wireless networks. Several scenarios have been presented and often the conclusions drawn are positive, showing increase in capacity. However, to date there has been no effort to assess a holistic picture of the benefit/cost tradeoff and previous work mainly concerns either link scheduling or antenna placement but not the two combined. Such consideration will become increasingly important in the near future with the advent of heterogeneous networks and other possible combinations of mesh and public access networks. In order to better understand the full implications and potential of using directional antennas in such systems, we present a model for determining the maximized benefit/cost tradeoff using a combination of directional and omnidirectional antennas in wireless multihop backbones. We study the problem of maximizing the minimal flow rate from gateways to mesh routers in the mesh network. A mixed integer programming model is formulated for joint optimization of antenna placement and link transmission scheduling under an antenna-aware SINR interference constraint and a budget constraint. An accurate antenna model is used and variable modulation and coding schemes are used. The model is decomposed to a master problem and a pricing problem, and solved by a branch-and-price algorithm. Additionally, two effective heuristics are proposed as supplement methods. Applying the introduced model makes it possible to deploy directional antennas at appropriate nodes and find a corresponding link transmission scheduling (with data rate adaptation). The numerical results show that introducing directional antennas can indeed substantially improve the considered traffic objective. Interestingly, the results also show that it is not always optimal to install directional antennas at all possible nodes because of increased interference observed at non-receiving nodes within the beam width. Finally, comparisons are made to show the effectiveness of the proposed solution methods.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125904963","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}
In this paper we introduce a mathematical model to analyze the performance of Wi-Fi networks carrying voice calls and TCP controlled file downloads. We derive the voice call capacity, the TCP throughput, and the bandwidth utilization using the proposed five-dimensional Markov model. We show that there exists a correlation among the queue size of client nodes and the capacity and throughput of the network. We also demonstrate how bandwidth utilization is affected by variable packet arrival rates. The analytical results match well with the simulation results generated by Qualnet simulator. Moreover, we conduct an experimental study of the Enhanced Distributed Channel Access (EDCA) mechanism of the IEEE 802.11e standard with a real-environment testbed consisting of 1 access point and 11 laptops to further validate the analytical and simulation results.
{"title":"Analyzing the effect of client queue size on VoIP and TCP traffic over an IEEE 802.11e WLAN","authors":"S. Datta, Sajal K. Das","doi":"10.1145/2507924.2507993","DOIUrl":"https://doi.org/10.1145/2507924.2507993","url":null,"abstract":"In this paper we introduce a mathematical model to analyze the performance of Wi-Fi networks carrying voice calls and TCP controlled file downloads. We derive the voice call capacity, the TCP throughput, and the bandwidth utilization using the proposed five-dimensional Markov model. We show that there exists a correlation among the queue size of client nodes and the capacity and throughput of the network. We also demonstrate how bandwidth utilization is affected by variable packet arrival rates. The analytical results match well with the simulation results generated by Qualnet simulator. Moreover, we conduct an experimental study of the Enhanced Distributed Channel Access (EDCA) mechanism of the IEEE 802.11e standard with a real-environment testbed consisting of 1 access point and 11 laptops to further validate the analytical and simulation results.","PeriodicalId":445138,"journal":{"name":"Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126658552","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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