2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks最新文献

{"title":"Performance of a reconfigurable antenna configuration selection scheme in a MIMO-OFDM system with modulation rate adaptation","authors":"David González, J. Kountouriotis, Daniel Lach, Renan Bertolazzi, Pujashree Das, K. Dandekar","doi":"10.1109/WIOPT.2011.5930032","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930032","url":null,"abstract":"In this paper we investigate the performance of an antenna configuration selection algorithm for a pattern recon-figurable antenna in a 2 × 2 MIMO-OFDM system. Channel capacity measurements were performed over a single link in both Line-of-sight (LOS) and Non-LOS (NLOS) indoor environments. From these measurements, an adaptive configuration selection algorithm was developed and the scheme's performance gains relative to a non-reconfigurable antenna were quantified. Finally, the configuration selection algorithm was also paired with a modulation rate adaptive scheme in order to exploit the improved channel capacity available with reconfigurable antennas.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131288181","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}

{"title":"Portfolio optimization in secondary spectrum markets","authors":"P. Muthuswamy, K. Kar, Aparna Gupta, S. Sarkar, G. Kasbekar","doi":"10.4108/ws.1.3.e3","DOIUrl":"https://doi.org/10.4108/ws.1.3.e3","url":null,"abstract":"In this paper, we address the spectrum portfolio optimization (SPO) question in the context of secondary spectrum markets, where bandwidth (spectrum access rights) can be bought in the form of primary and secondary contracts. While a primary contract on a channel provides guaranteed access to the channel bandwidth (possibly at a higher per-unit price), the bandwidth available to use from a secondary contract (possibly at a discounted price) is typically uncertain/stochastic. The key problem for the buyer (service provider) in this market is to determine the amount of primary and secondary contract units needed to satisfy uncertain user demand. We initially consider a single-region problem in which the spectrum contracts are valid only in the single-region in which the buyer wishes to provide service. We formulate the problem as one of minimizing the cost of the spectrum portfolio subject to constraints on bandwidth shortage. Two different forms of bandwidth shortage constraints are considered, namely, the demand satisfaction rate constraint, and the demand satisfaction probability constraint. While the SPO problem under demand satisfaction rate constraint is shown to be convex for all density functions, the SPO problem under demand satisfaction probability constraint is not convex in general. We derive some sufficient conditions for convexity for this case. The SPO problems can therefore be solved efficiently using standard convex optimization techniques. Later, we extend the problem formulation and the convexity results to the multiple-region setting, where the buyer's portfolio is intended to serve a set of disjoint geographical locations, each having its own customer demand. Finally, we perform a thorough simulation-based study of the single-region and the multiple-region problems for different choices of the problem parameters, and provide key insights regarding the portfolio composition and demonstrate the convexity of the efficient frontier. We provide several insights about the scaling behavior of the unit prices of the secondary contracts, as the stochastic characterization of the bandwidth available from secondary contracts change.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115712200","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}

{"title":"A coalition game approach to the association problem of mobiles in broadcast transmission","authors":"Cengis Hasan, E. Altman, J. Gorce","doi":"10.1109/WIOPT.2011.5930021","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930021","url":null,"abstract":"We consider a common object (data) that each mobile in the medium is interested to receive, and which can be obtained from any base station transmitting the data. For example, the broadcast object could be streaming transmission of a sport or cultural event, or it could be some signaling such as a beacon for time synchronization or for power control purposes. This problem can be conceived as a coalition game played by mobiles which we call as association game of mobiles. This game has an incentive to form grand coalition where all players join to the game. We prove that using Bondareva-Shapley theorem, this coalition game has a non-empty core which means that grand coalition is stable. Then, we examine the cost allocation policy for different methods such as egalitarian allocation, proportional repartition of total cost, the Shapley value and the nucleolus. We also conclude that if the nucleolus is used as the cost allocation algorithm, the players maintain the grand coalition satisfying the minimization of total cost for broadcast transmission.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115963263","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}

{"title":"Efficient and fair MAC for wireless networks with self-interference cancellation","authors":"Nikhil Singh, Dinan Gunawardena, A. Proutière, B. Radunovic, Horia Vlad Balan, P. Key","doi":"10.1109/WIOPT.2011.5930070","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930070","url":null,"abstract":"Recent advances in PHY layer design demonstrated efficient self-interference cancellation and full-duplex in a single band. Building a MAC that exploits self-interference cancellation is a challenging task. Links can be scheduled concurrently, but only if they either (i) don't interfere or (ii) allow for self-interference cancellation. Two issues arise: Firstly, it is difficult to construct a schedule that fully exploits the potentials for self-interference cancellation for arbitrary traffic patterns. Secondly, designing an efficient and fair distributed MAC is a daunting task; the issues become even more pronounced when scheduling under the constraints. We propose ContraFlow, a novel MAC that exploits the benefits of self-interference cancellation and increases spatial reuse. We use full-duplex to eliminate hidden terminals, and we rectify decentralized coordination inefficiencies among nodes, thereby improving fairness. Using measurements and simulations we illustrate the performance gains achieved when ContraFlow is used and we obtain both a throughput increase over current systems, as well as a significant improvement in fairness.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127701039","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}

{"title":"Contention and traffic load-aware association in IEEE 802.11 WLANs: Algorithms and implementation","authors":"Stratos Keranidis, T. Korakis, I. Koutsopoulos, L. Tassiulas","doi":"10.1109/WIOPT.2011.5930036","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930036","url":null,"abstract":"Efficient association of a station with the appropriate access point has always been a challenging problem. The standard approach of considering only the Received Signal Strength, has recently been substituted by more efficient schemes that consider channel conditions, cell population etc. However, in spite of the large variety of approaches, several factors that determine to a large extent user throughput after association with an access point have been overlooked. In this work, we propose innovative metrics on which association should be based. First, we capture the contention from one-hop and interference from two-hop neighbors that is inherent in IEEE 802.11 WLAN environments. Second we include the PHY transmission rate and show preference to higher rates that reduce the above effects. Third, unlike most relevant approaches, we define an activity factor that reveals the anticipated activity due to backlogged traffic. We devise an association protocol suite, through which messages containing the information above are passed between the AP and the user to support association decisions for the uplink and downlink. We implement the proposed mechanism using the MAD-WiFi open source driver and moreover show through experiments in a wireless testbed that it significantly improves user performance in real conditions.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128578101","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}

{"title":"Understanding IEEE 802.11n multi-hop communication in wireless networks","authors":"Jan Friedrich, Simon Frohn, Sascha Gübner, C. Lindemann","doi":"10.1109/WIOPT.2011.5930034","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930034","url":null,"abstract":"In this paper, we present a measurement study of the multi-hop behavior of the new IEEE 802.11n standard in an indoor mesh testbed. As main contribution, we quantitatively describe characteristics of IEEE 802.11n on multi-hop paths like throughput, aggregate size and utilized MIMO features. Furthermore, we show how to build an IEEE 802.11n indoor testbed capable of multi-hop communication. In an 8-hop chain topology, we observe that channel bonding nearly doubles the throughput for any fixed path length. The mean aggregate size in number of frames at each node is also doubled by channel bonding. The aggregate size decreases with increasing path length. Limiting the aggregate size severely impacts throughput both on single and multi-hop paths. The throughput degrades as the path length is increased as in legacy IEEE 802.11a/b/g. We believe that these findings will enhance the understanding of the performance of IEEE 802.11n in multi-hop networks.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121698652","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}

{"title":"Linear precoding in MIMO broadcast channel with arbitrary rank constraints","authors":"M. Khajehnejad, M. Khojastepour, G. Yue","doi":"10.1109/WIOPT.2011.5930028","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930028","url":null,"abstract":"We consider the problem of maximizing the weighted sum rate (WSR) in MIMO broadcast channel where the number of transmitted streams (ranks) is constrained. The problem is treated both with or without interference pre-compensation also known as dirty paper coding (DPC). The rank constrained problem is highly motivated by the practical consideration on the receiver complexity in current wireless systems such as LTE. We propose a unified algorithm based on fixed point iteration. The proposed approach has very fast convergence rate that usually converges to the minimal number of streams for each user and finds the corresponding optimal precoding matrix. Rank minimization is particularly desirable in practice. The order in which the users' streams are encoded is crucial when dirty paper coding is allowed. We prove that the optimal user ordering does not depend on the transmission rank constraints and is given only by the weight vector. Using simulations, we compare the performance of our proposed scheme with the best known algorithms in the literature and demonstrate the effect of rank constraints.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121853927","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}

{"title":"On the gradual deployment of random pairwise key distribution schemes","authors":"Osman Yağan, A. Makowski","doi":"10.1109/WIOPT.2011.5930024","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930024","url":null,"abstract":"The pairwise key distribution scheme of Chan et al. is a randomized key predistribution scheme which enables cryptographic protection in wireless sensor networks (WSNs). This pairwise scheme has many advantages over other randomized key predistribution schemes but has been deemed non-scalable due to (i) the large number of keys required to ensure secure connectivity; and (ii) implementation difficulties when sensors are required to be deployed in multiple stages. Here, we address this issue by proposing an implementation of the pairwise scheme that supports the gradual deployment of sensor nodes in several consecutive phases. We show how the scheme parameter should be adjusted with the number n of sensors so that secure connectivity is maintained in the network throughout all the stages of the deployment. We also discuss briefly the relation between the scheme parameter and the amount of memory that each sensor needs to spare for storing their keys. By showing that O(log n) many keys per node suffice to achieve secure connectivity at every step of the deployment, we confirm the scalability of the pairwise scheme in the context of WSNs.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115598036","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}

{"title":"Adaptive resource allocation in jamming teams using game theory","authors":"A. Khanafer, S. Bhattacharya, T. Başar","doi":"10.1109/WIOPT.2011.5930051","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930051","url":null,"abstract":"In this work, we study the problem of power allocation and adaptive modulation in teams of decision makers. We consider the special case of two teams with each team consisting of two mobile agents. Agents belonging to the same team communicate over wireless ad hoc networks, and they try to split their available power between the tasks of communication and jamming the nodes of the other team. The agents have constraints on their total energy and instantaneous power usage. The cost function adopted is the difference between the rates of erroneously transmitted bits of each team. We model the adaptive modulation problem as a zero-sum matrix game which in turn gives rise to a a continuous kernel game to handle power control. Based on the communications model, we present sufficient conditions on the physical parameters of the agents for the existence of a pure strategy saddle-point equilibrium (PSSPE).","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129841626","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}

{"title":"Scheduling with per-link queues and no per-flow information in multi-hop wireless networks","authors":"Bo Ji, Changhee Joo, N. Shroff","doi":"10.1109/WIOPT.2011.5930025","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930025","url":null,"abstract":"This paper focuses on designing and analyzing throughput-optimal scheduling policies that avoid using per-flow or per-destination information, maintain a single data queue for each link, exploit only local information, and potentially improve the delay performance, for multi-hop wireless networks under general interference constraints. Although the celebrated backpressure algorithm maximizes throughput, it requires per-flow or per-destination information (which may be difficult to obtain and maintain), maintains per-flow or per-destination queues at each node, relies on constant exchange of queue length information among neighboring nodes to calculate link weights, and may result in poor delay performance. In contrast, the proposed schemes can circumvent these drawbacks while guaranteeing throughput optimality. We rigorously analyze the throughput performance of the proposed schemes and show that they are throughput-optimal using fluid limit techniques via an inductive argument. We also conduct simulations to show that the proposed schemes can substantially improve the delay performance.","PeriodicalId":430755,"journal":{"name":"2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126959188","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}