Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959925
Craig B. Schindler, T. Watteyne, Xavier Vilajosana, K. Pister
6TiSCH is a technology being standardized at the IETF which brings determinism to low-power wireless communication. In a 6TiSCH network, all communication is orchestrated by a communication schedule. This paper explores the applicability of this new technology to control systems. In particular, we apply it to the inverted pendulum, a canonical control system in which a cart moves along a track to keep a pendulum — which naturally falls over — upright. This paper presents the first characterization and implementation of a closed-loop wireless feedback control network using completely standards-compliant IEEE802.15.4 TSCH technology. First, we implement a control loop in OpenWSN and experimentally evaluate the performance of the network by varying the radio duty cycle, number of hops, and introducing controlled external interference. We show that 100% reliability can be achieved while maintaining latencies well below the critical delay of the system. Second, we use the network on an inverted pendulum system and show that angular deviations from the upright position do not exceed 3 degrees, even in a multi-hop setup. Finally, we discuss the results in detail, and advocate for a co-design of the controller and the networking system.
{"title":"Implementation and characterization of a multi-hop 6TiSCH network for experimental feedback control of an inverted pendulum","authors":"Craig B. Schindler, T. Watteyne, Xavier Vilajosana, K. Pister","doi":"10.23919/WIOPT.2017.7959925","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959925","url":null,"abstract":"6TiSCH is a technology being standardized at the IETF which brings determinism to low-power wireless communication. In a 6TiSCH network, all communication is orchestrated by a communication schedule. This paper explores the applicability of this new technology to control systems. In particular, we apply it to the inverted pendulum, a canonical control system in which a cart moves along a track to keep a pendulum — which naturally falls over — upright. This paper presents the first characterization and implementation of a closed-loop wireless feedback control network using completely standards-compliant IEEE802.15.4 TSCH technology. First, we implement a control loop in OpenWSN and experimentally evaluate the performance of the network by varying the radio duty cycle, number of hops, and introducing controlled external interference. We show that 100% reliability can be achieved while maintaining latencies well below the critical delay of the system. Second, we use the network on an inverted pendulum system and show that angular deviations from the upright position do not exceed 3 degrees, even in a multi-hop setup. Finally, we discuss the results in detail, and advocate for a co-design of the controller and the networking system.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79442695","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959937
A. Cika, J. Coon, Sunwoo Kim
We study the effect of anisotropic radiation on wireless network complexity. To this end, we model a wireless network as a random geometric graph where nodes have random antenna orientations as well as random positions, and communication is affected by Rayleigh fading. Complexity is quantified by computing the Shannon entropy of the underlying graph model. We use this formalism to develop analytic scaling results that describe how complexity can be controlled by varying key system parameters such as the transmit power and the directivity of transmissions in large-scale networks. Our results point to striking contrasts between power scaling and directivity scaling in the large connection range regime.
{"title":"Effects of directivity on wireless network complexity","authors":"A. Cika, J. Coon, Sunwoo Kim","doi":"10.23919/WIOPT.2017.7959937","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959937","url":null,"abstract":"We study the effect of anisotropic radiation on wireless network complexity. To this end, we model a wireless network as a random geometric graph where nodes have random antenna orientations as well as random positions, and communication is affected by Rayleigh fading. Complexity is quantified by computing the Shannon entropy of the underlying graph model. We use this formalism to develop analytic scaling results that describe how complexity can be controlled by varying key system parameters such as the transmit power and the directivity of transmissions in large-scale networks. Our results point to striking contrasts between power scaling and directivity scaling in the large connection range regime.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78851154","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959917
Anup Chaudhari, C. Murthy
The future 5G cellular networks are expected to support several-fold increase in data traffic and number of devices, and provide a very low latency and gigabit-rate data services. millimeter Wave (mmWave) communication (30–300 GHz) is proposed to be an important part of the 5G cellular networks to fulfill these requirements. With most of the high data rate demands originating from indoor User Equipments (UEs), conventional wired backhaul links prove to be a major bottleneck. Hence, mmWave wireless backhaul links are explored at Femto Base Stations (FBSs). In order to derive maximum benefit of mmWave backhaul links, efficient resource (data slots) utilization is necessary. Proper scheduling of mmWave backhaul links will help to achieve the same. In this paper, we propose a novel FBS-to-FBS (F2F) communication scheme which not only helps in offloading the data traffic from the Micro Base Station (MiBS) but also can act as a relay link for the other FBSs for routing the backhaul traffic to the MiBS. We also propose a solution to concurrently schedule mmWave wireless backhaul links to increase the resource utilization considering the coexistence of both FBS-to-MiBS (F2M) and F2F links. Our proposed solution consists of two parts — first, it determines which backhaul links can be scheduled concurrently by finding the upper bound for the interfering distance based on the alignment of different lobes of the directional antennas. Second, the transmit power is throttled to match the Quality of Service (QoS) requirements of each link aiming to further control the interference and to increase the number of concurrent transmissions. The benefits of the proposed solution are studied and compared with the Time Division Multiple Access (TDMA) and random scheduling schemes using extensive simulations.
{"title":"Femto-to-Femto (F2F) communication: The next evolution step in 5G wireless backhauling","authors":"Anup Chaudhari, C. Murthy","doi":"10.23919/WIOPT.2017.7959917","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959917","url":null,"abstract":"The future 5G cellular networks are expected to support several-fold increase in data traffic and number of devices, and provide a very low latency and gigabit-rate data services. millimeter Wave (mmWave) communication (30–300 GHz) is proposed to be an important part of the 5G cellular networks to fulfill these requirements. With most of the high data rate demands originating from indoor User Equipments (UEs), conventional wired backhaul links prove to be a major bottleneck. Hence, mmWave wireless backhaul links are explored at Femto Base Stations (FBSs). In order to derive maximum benefit of mmWave backhaul links, efficient resource (data slots) utilization is necessary. Proper scheduling of mmWave backhaul links will help to achieve the same. In this paper, we propose a novel FBS-to-FBS (F2F) communication scheme which not only helps in offloading the data traffic from the Micro Base Station (MiBS) but also can act as a relay link for the other FBSs for routing the backhaul traffic to the MiBS. We also propose a solution to concurrently schedule mmWave wireless backhaul links to increase the resource utilization considering the coexistence of both FBS-to-MiBS (F2M) and F2F links. Our proposed solution consists of two parts — first, it determines which backhaul links can be scheduled concurrently by finding the upper bound for the interfering distance based on the alignment of different lobes of the directional antennas. Second, the transmit power is throttled to match the Quality of Service (QoS) requirements of each link aiming to further control the interference and to increase the number of concurrent transmissions. The benefits of the proposed solution are studied and compared with the Time Division Multiple Access (TDMA) and random scheduling schemes using extensive simulations.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77987942","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959945
Mostafa Emara, Hesham Elsawy, Sameh Sorour, S. Al-Ghadhban, Mohamed-Slim Alouini, T. Al-Naffouri
Cache-enabled base station (BS) densification, denoted as a fog radio access network (F-RAN), is foreseen as a key component of 5G cellular networks. F-RAN enables storing popular files at the network edge (i.e., BS caches), which empowers local communication and alleviates traffic congestions at the core/backhaul network. The hitting probability, which is the probability of successfully transmitting popular files request from the network edge, is a fundamental key performance indicator (KPI) for F-RAN. This paper develops a scheduling aware mathematical framework, based on stochastic geometry, to characterize the hitting probability of F-RAN in a multi-channel environment. To this end, we assess and compare the performance of two caching distribution schemes, namely, uniform caching and Zipf caching. The numerical results show that the commonly used single channel environment leads to pessimistic assessment for the hitting probability of F-RAN. Furthermore, the numerical results manifest the superiority of the Zipf caching scheme and quantify the hitting probability gains in terms of the number of channels and cache size.
{"title":"Stochastic geometry model for multi-channel fog radio access networks","authors":"Mostafa Emara, Hesham Elsawy, Sameh Sorour, S. Al-Ghadhban, Mohamed-Slim Alouini, T. Al-Naffouri","doi":"10.23919/WIOPT.2017.7959945","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959945","url":null,"abstract":"Cache-enabled base station (BS) densification, denoted as a fog radio access network (F-RAN), is foreseen as a key component of 5G cellular networks. F-RAN enables storing popular files at the network edge (i.e., BS caches), which empowers local communication and alleviates traffic congestions at the core/backhaul network. The hitting probability, which is the probability of successfully transmitting popular files request from the network edge, is a fundamental key performance indicator (KPI) for F-RAN. This paper develops a scheduling aware mathematical framework, based on stochastic geometry, to characterize the hitting probability of F-RAN in a multi-channel environment. To this end, we assess and compare the performance of two caching distribution schemes, namely, uniform caching and Zipf caching. The numerical results show that the commonly used single channel environment leads to pessimistic assessment for the hitting probability of F-RAN. Furthermore, the numerical results manifest the superiority of the Zipf caching scheme and quantify the hitting probability gains in terms of the number of channels and cache size.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88900750","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959909
G. Nguyen, S. Kompella, C. Kam, J. Wieselthier, A. Ephremides
For time critical updates, it is desirable to maintain the freshness of the received information. We address the impact of hostile interference on information freshness by formulating a non-zero-sum two-player game, in which one player is the transmitter aiming to maintain the freshness of the information updates it sends to its receiver, and the other player is the interferer aiming to prevent this. The strategy of a player is the power level transmitted by that player. We then derive the equilibria for both Nash and Stackelberg strategies. We show that both players have the same power cost at Nash equilibrium. In addition, the Stackelberg strategy dominates the Nash strategy, i.e., the Stackelberg utility function exceeds the Nash utility function.
{"title":"Impact of hostile interference on information freshness: A game approach","authors":"G. Nguyen, S. Kompella, C. Kam, J. Wieselthier, A. Ephremides","doi":"10.23919/WIOPT.2017.7959909","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959909","url":null,"abstract":"For time critical updates, it is desirable to maintain the freshness of the received information. We address the impact of hostile interference on information freshness by formulating a non-zero-sum two-player game, in which one player is the transmitter aiming to maintain the freshness of the information updates it sends to its receiver, and the other player is the interferer aiming to prevent this. The strategy of a player is the power level transmitted by that player. We then derive the equilibria for both Nash and Stackelberg strategies. We show that both players have the same power cost at Nash equilibrium. In addition, the Stackelberg strategy dominates the Nash strategy, i.e., the Stackelberg utility function exceeds the Nash utility function.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82809988","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959919
Nof Abuzainab, W. Saad, B. Maham
In this paper, the problem of adversarial learning is studied for a wireless powered communication network (WPCN) in which a hybrid access point (HAP) seeks to learn the transmission power consumption profile of an associated wireless transmitter. The objective of the HAP is to use the learned estimate in order to determine the transmission power of the energy signal to be supplied to its associated device. However, such a learning scheme is subject to attacks by an adversary who tries to alter the HAP's learned estimate of the transmission power distribution in order to minimize the HAP's supplied energy. To build a robust estimate against such attacks, an unsupervised Bayesian learning method is proposed allowing the HAP to perform its estimation based only on the advertised transmisson power computed in each time slot. The proposed robust learning method relies on the assumption that the device's true transmission power is greater than or equal to advertised value. Then, based on the robust estimate, the problem of power selection of the energy signal by the HAP is formulated. The HAP optimal power selection problem is shown to be a discrete convex optimization problem, and a closed-form solution of the HAP's optimal transmission power is obtained. The results show that the proposed robust Bayesian learning scheme yields significant performance gains, by reducing the percentage of dropped transmitter's packets of about 85% compared to a conventional Bayesian learning approach. The results also show that these performance gains are achieved without jeopardizing the energy consumption of the HAP.
{"title":"Robust Bayesian learning for wireless RF energy harvesting networks","authors":"Nof Abuzainab, W. Saad, B. Maham","doi":"10.23919/WIOPT.2017.7959919","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959919","url":null,"abstract":"In this paper, the problem of adversarial learning is studied for a wireless powered communication network (WPCN) in which a hybrid access point (HAP) seeks to learn the transmission power consumption profile of an associated wireless transmitter. The objective of the HAP is to use the learned estimate in order to determine the transmission power of the energy signal to be supplied to its associated device. However, such a learning scheme is subject to attacks by an adversary who tries to alter the HAP's learned estimate of the transmission power distribution in order to minimize the HAP's supplied energy. To build a robust estimate against such attacks, an unsupervised Bayesian learning method is proposed allowing the HAP to perform its estimation based only on the advertised transmisson power computed in each time slot. The proposed robust learning method relies on the assumption that the device's true transmission power is greater than or equal to advertised value. Then, based on the robust estimate, the problem of power selection of the energy signal by the HAP is formulated. The HAP optimal power selection problem is shown to be a discrete convex optimization problem, and a closed-form solution of the HAP's optimal transmission power is obtained. The results show that the proposed robust Bayesian learning scheme yields significant performance gains, by reducing the percentage of dropped transmitter's packets of about 85% compared to a conventional Bayesian learning approach. The results also show that these performance gains are achieved without jeopardizing the energy consumption of the HAP.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89760794","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 : 2017-05-15DOI: 10.23919/WIOPT.2017.7959950
J. Nadas, M. Imran, G. Brante, R. Souza
We evaluate the use of HARQ schemes in the context of vehicle to infrastructure communications considering ultra reliable communications in the short term from a channel capacity stand point. We show that it is not possible to meet strict latency requirements with very high reliability without some diversity strategy and propose a solution to determining an optimal limit on the maximum allowed number of retransmissions using Chase combining and simple HARQ to increase energy efficiency. Results show that using the proposed optimizations leads to spending 5 times less energy when compared to only one retransmission in the context of a benchmark test case for urban scenario. In addition, we present an approximation that relates most system parameters and can predict whether or not the link can be closed, which is valuable for system design.
{"title":"Optimizing the energy efficiency of short term ultra reliable communications in vehicular networks","authors":"J. Nadas, M. Imran, G. Brante, R. Souza","doi":"10.23919/WIOPT.2017.7959950","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959950","url":null,"abstract":"We evaluate the use of HARQ schemes in the context of vehicle to infrastructure communications considering ultra reliable communications in the short term from a channel capacity stand point. We show that it is not possible to meet strict latency requirements with very high reliability without some diversity strategy and propose a solution to determining an optimal limit on the maximum allowed number of retransmissions using Chase combining and simple HARQ to increase energy efficiency. Results show that using the proposed optimizations leads to spending 5 times less energy when compared to only one retransmission in the context of a benchmark test case for urban scenario. In addition, we present an approximation that relates most system parameters and can predict whether or not the link can be closed, which is valuable for system design.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86496070","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 : 2017-05-01DOI: 10.23919/WIOPT.2017.7959940
Farnaz Moradi, M. Karaca, Emma Fitzgerald, M. Pióro, R. Ljung, B. Landfeldt
We jointly optimize Discontinuous Reception (DRX) cycle length and LTE scheduling to minimize mobile devices' energy usage for video delivery, utilising the now well-established potential to predict future channel conditions in cellular networks. Employing in-network caching, we set a strict buffer constraint which provides zero buffer underflow to improve Quality of Experience. Our study provides insight into the energy saving potential sophisticated DRX schemes hold, compared with the currently used static method. To this end, two novel DRX approaches are proposed and studied. The results show that more sophisticated DRX schemes (with variable DRX cycle length) can potentially save 69 percent energy for mobile devices, encouraging further research in the field.
{"title":"Optimizing DRX for video delivery over LTE: Utilizing channel prediction and in-network caching","authors":"Farnaz Moradi, M. Karaca, Emma Fitzgerald, M. Pióro, R. Ljung, B. Landfeldt","doi":"10.23919/WIOPT.2017.7959940","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959940","url":null,"abstract":"We jointly optimize Discontinuous Reception (DRX) cycle length and LTE scheduling to minimize mobile devices' energy usage for video delivery, utilising the now well-established potential to predict future channel conditions in cellular networks. Employing in-network caching, we set a strict buffer constraint which provides zero buffer underflow to improve Quality of Experience. Our study provides insight into the energy saving potential sophisticated DRX schemes hold, compared with the currently used static method. To this end, two novel DRX approaches are proposed and studied. The results show that more sophisticated DRX schemes (with variable DRX cycle length) can potentially save 69 percent energy for mobile devices, encouraging further research in the field.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74154985","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 : 2017-05-01DOI: 10.23919/WIOPT.2017.7959880
Harel Yedidsion, Aritra Banik, Paz Carmi, M. J. Katz, M. Segal
In this paper, we study the problem of data gathering in ad-hoc sensor networks using a mobile entity called mule. The mule traverses the children of failed sensors, to prevent loss of data. Our objective is to define the optimal communication tree and the mule's placement such that the mule's overall traveling distance is minimized. We explore this problem in several network topologies including: unit disc graph on a line (UDL), general unit disc graph (UDG), and a complete graph with failing probabilities on the nodes (CGFP). We provide an optimal solution for the UDL problem and two approximation algorithms for the UDG problem. For the CGFP problem we outline the two possible structures of an optimal solution and provide near optimal approximation algorithms.
{"title":"Efficient data retrieval in faulty sensor networks using a mobile mule","authors":"Harel Yedidsion, Aritra Banik, Paz Carmi, M. J. Katz, M. Segal","doi":"10.23919/WIOPT.2017.7959880","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959880","url":null,"abstract":"In this paper, we study the problem of data gathering in ad-hoc sensor networks using a mobile entity called mule. The mule traverses the children of failed sensors, to prevent loss of data. Our objective is to define the optimal communication tree and the mule's placement such that the mule's overall traveling distance is minimized. We explore this problem in several network topologies including: unit disc graph on a line (UDL), general unit disc graph (UDG), and a complete graph with failing probabilities on the nodes (CGFP). We provide an optimal solution for the UDL problem and two approximation algorithms for the UDG problem. For the CGFP problem we outline the two possible structures of an optimal solution and provide near optimal approximation algorithms.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83856251","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 : 2017-05-01DOI: 10.23919/WIOPT.2017.7959890
R. Divya, A. Azad, C. Singh
We study an offloading mechanism for cellular networks in which mobiles with good cellular links can act as hotspots and can assist other mobiles. We study throughput optimal offloading and also a fair offloading strategy which we call proportional increment offloading. We show that the former problem can be reduced to a capacitated facility location problem (CFLP) whereas the latter can be solved by solving a sequence of CFLPs. We propose a belief propagation based algorithm to solve CFLP, a well known NP complete problem. We primarily consider point coordination function (PCF) based WiFi access for offloading but also discuss distributed coordination function (DCF) based access and related issues. Further, we argue that all the mobiles benefit through participating in offloading. We perform extensive simulation to evaluate the performance of the proposed algorithms and effectiveness of mobile assisted offloading.
{"title":"Fair and optimal mobile assisted offloading","authors":"R. Divya, A. Azad, C. Singh","doi":"10.23919/WIOPT.2017.7959890","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959890","url":null,"abstract":"We study an offloading mechanism for cellular networks in which mobiles with good cellular links can act as hotspots and can assist other mobiles. We study throughput optimal offloading and also a fair offloading strategy which we call proportional increment offloading. We show that the former problem can be reduced to a capacitated facility location problem (CFLP) whereas the latter can be solved by solving a sequence of CFLPs. We propose a belief propagation based algorithm to solve CFLP, a well known NP complete problem. We primarily consider point coordination function (PCF) based WiFi access for offloading but also discuss distributed coordination function (DCF) based access and related issues. Further, we argue that all the mobiles benefit through participating in offloading. We perform extensive simulation to evaluate the performance of the proposed algorithms and effectiveness of mobile assisted offloading.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90979698","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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