%0 Conference Paper
%B 2011 Proceedings IEEE INFOCOM
%D 2011
%T Approximation algorithms for throughput maximization in wireless networks with delay constraints
%A Guanhong Pei
%A Anil Kumar,V. S
%A Parthasarathy,S.
%A Srinivasan, Aravind
%K Approximation algorithms
%K Approximation methods
%K approximation theory
%K Delay
%K delay constraints
%K delays
%K general interference model
%K Interference
%K multihop wireless networks
%K optimisation
%K Optimized production technology
%K radio networks
%K radiofrequency interference
%K target delay bound
%K Throughput
%K throughput maximization
%K Wireless networks
%X We study the problem of throughput maximization in multi-hop wireless networks with end-to-end delay constraints for each session. This problem has received much attention starting with the work of Grossglauser and Tse (2002), and it has been shown that there is a significant tradeoff between the end-to-end delays and the total achievable rate. We develop algorithms to compute such tradeoffs with provable performance guarantees for arbitrary instances, with general interference models. Given a target delay-bound Δ(c) for each session c, our algorithm gives a stable flow vector with a total throughput within a factor of O (logΔm/log log Δm) of the maximum, so that the per-session (end-to-end) delay is O ((logΔm/log log Δm Δ(c))2), where Δm = maxc{Δ(c)}; note that these bounds depend only on the delays, and not on the network size, and this is the first such result, to our knowledge.
%B 2011 Proceedings IEEE INFOCOM
%I IEEE
%P 1116 - 1124
%8 2011/04/10/15
%@ 978-1-4244-9919-9
%G eng
%R 10.1109/INFCOM.2011.5934887
%0 Journal Article
%J Theoretical Computer Science
%D 2011
%T Maximum bipartite flow in networks with adaptive channel width
%A Azar,Yossi
%A Mądry,Aleksander
%A Moscibroda,Thomas
%A Panigrahi,Debmalya
%A Srinivasan, Aravind
%K Adaptive channel width
%K graph algorithm
%K Linear program rounding
%K Maximum flow
%K Wireless networks
%X Traditionally, network optimization problems assume that each link in the network has a fixed capacity. Recent research in wireless networking has shown that it is possible to design networks where the capacity of the links can be changed adaptively to suit the needs of specific applications. In particular, one gets a choice of having a few high capacity outgoing links or many low capacity ones at any node of the network. This motivates us to have a re-look at classical network optimization problems and design algorithms to solve them in this new framework. In particular, we consider the problem of maximum bipartite flow, which has been studied extensively in the fixed-capacity network model. One of the motivations for studying this problem arises from the need to maximize the throughput of an infrastructure wireless network comprising base-stations (one set of vertices in the bipartition) and clients (the other set of vertices in the bipartition). We show that this problem has a significantly different combinatorial structure in this new network model from the fixed-capacity one. While there are several polynomial time algorithms for the maximum bipartite flow problem in traditional networks, we show that the problem is NP-hard in the new model. In fact, our proof extends to showing that the problem is APX-hard. We complement our lower bound by giving two algorithms for solving the problem approximately. The first algorithm is deterministic and achieves an approximation factor of O ( log N ) , where N is the number of nodes in the network, while the second algorithm is randomized and achieves an approximation factor of e e − 1 .
%B Theoretical Computer Science
%V 412
%P 2577 - 2587
%8 2011/05/27/
%@ 0304-3975
%G eng
%U http://www.sciencedirect.com/science/article/pii/S0304397510005852
%N 24
%R 10.1016/j.tcs.2010.10.023
%0 Conference Paper
%B IEEE INFOCOM 2009
%D 2009
%T Distributed Strategies for Channel Allocation and Scheduling in Software-Defined Radio Networks
%A Han,Bo
%A Kumar,V. S.A
%A Marathe,M. V
%A Parthasarathy,S.
%A Srinivasan, Aravind
%K access hash function
%K Channel allocation
%K channel assignment algorithm
%K channel capacity
%K collision avoidance
%K Computer science
%K cryptography
%K distributed algorithm
%K distributed algorithms
%K Educational institutions
%K inductive-scheduling technique
%K Interference
%K interference set
%K packet scheduling algorithm
%K Peer to peer computing
%K Radio network
%K radio networks
%K radiofrequency interference
%K random oracle methodology
%K scheduling
%K Scheduling algorithm
%K simultaneous channel allocation
%K software radio
%K software-defined radio wireless network capacity
%K telecommunication congestion control
%K telecommunication security
%K Throughput
%K wireless channels
%K Wireless networks
%X Equipping wireless nodes with multiple radios can significantly increase the capacity of wireless networks, by making these radios simultaneously transmit over multiple non-overlapping channels. However, due to the limited number of radios and available orthogonal channels, designing efficient channel assignment and scheduling algorithms in such networks is a major challenge. In this paper, we present provably-good distributed algorithms for simultaneous channel allocation of individual links and packet-scheduling, in software-defined radio (SDR) wireless networks. Our distributed algorithms are very simple to implement, and do not require any coordination even among neighboring nodes. A novel access hash function or random oracle methodology is one of the key drivers of our results. With this access hash function, each radio can know the transmitters' decisions for links in its interference set for each time slot without introducing any extra communication overhead between them. Further, by utilizing the inductive-scheduling technique, each radio can also backoff appropriately to avoid collisions. Extensive simulations demonstrate that our bounds are valid in practice.
%B IEEE INFOCOM 2009
%I IEEE
%P 1521 - 1529
%8 2009/04/19/25
%@ 978-1-4244-3512-8
%G eng
%R 10.1109/INFCOM.2009.5062069
%0 Conference Paper
%B IEEE INFOCOM 2008. The 27th Conference on Computer Communications
%D 2008
%T Approximation Algorithms for Computing Capacity of Wireless Networks with SINR Constraints
%A Chafekar,D.
%A Kumart,V. S.A
%A Marathe,M. V
%A Parthasarathy,S.
%A Srinivasan, Aravind
%K Algorithm design and analysis
%K approximation algorithm
%K Approximation algorithms
%K approximation theory
%K Computer networks
%K Computer science
%K graph theory
%K graph-based model
%K Interference constraints
%K polynomial time algorithm
%K Propagation losses
%K Protocols
%K radio networks
%K radiofrequency interference
%K signal to interference plus noise ratio
%K Signal to noise ratio
%K Throughput
%K wireless interference
%K wireless network
%K Wireless networks
%X A fundamental problem in wireless networks is to estimate its throughput capacity - given a set of wireless nodes, and a set of connections, what is the maximum rate at which data can be sent on these connections. Most of the research in this direction has focused on either random distributions of points, or has assumed simple graph-based models for wireless interference. In this paper, we study capacity estimation problem using the more general Signal to Interference Plus Noise Ratio (SINR) model for interference, on arbitrary wireless networks. The problem becomes much harder in this setting, because of the non-locality of the SINR model. Recent work by Moscibroda et al. (2006) has shown that the throughput in this model can differ from graph based models significantly. We develop polynomial time algorithms to provably approximate the total throughput in this setting.
%B IEEE INFOCOM 2008. The 27th Conference on Computer Communications
%I IEEE
%P 1166 - 1174
%8 2008/04/13/18
%@ 978-1-4244-2025-4
%G eng
%R 10.1109/INFOCOM.2008.172
%0 Conference Paper
%B IEEE INFOCOM 2008. The 27th Conference on Computer Communications
%D 2008
%T Capacity of Asynchronous Random-Access Scheduling in Wireless Networks
%A Chafekar,D.
%A Levin,D.
%A Kumar,V. S.A
%A Marathe,M. V
%A Parthasarathy,S.
%A Srinivasan, Aravind
%K asynchronous random-access scheduling
%K channel access probability
%K Computer networks
%K Computer science
%K Educational institutions
%K Interference
%K Optimal scheduling
%K Peer to peer computing
%K probability
%K Processor scheduling
%K radio link
%K radio links
%K radio networks
%K Routing
%K scheduling
%K Throughput
%K throughput capacity
%K wireless channels
%K Wireless networks
%X We study the throughput capacity of wireless networks which employ (asynchronous) random-access scheduling as opposed to deterministic scheduling. The central question we answer is: how should we set the channel-access probability for each link in the network so that the network operates close to its optimal throughput capacity? We design simple and distributed channel-access strategies for random-access networks which are provably competitive with respect to the optimal scheduling strategy, which is deterministic, centralized, and computationally infeasible. We show that the competitiveness of our strategies are nearly the best achievable via random-access scheduling, thus establishing fundamental limits on the performance of random- access. A notable outcome of our work is that random access compares well with deterministic scheduling when link transmission durations differ by small factors, and much worse otherwise. The distinguishing aspects of our work include modeling and rigorous analysis of asynchronous communication, asymmetry in link transmission durations, and hidden terminals under arbitrary link-conflict based wireless interference models.
%B IEEE INFOCOM 2008. The 27th Conference on Computer Communications
%I IEEE
%P 1148 - 1156
%8 2008/04/13/18
%@ 978-1-4244-2025-4
%G eng
%R 10.1109/INFOCOM.2008.170
%0 Conference Paper
%B Proceedings of the 8th ACM international symposium on Mobile ad hoc networking and computing
%D 2007
%T Cross-layer latency minimization in wireless networks with SINR constraints
%A Chafekar,Deepti
%A Kumar,V. S. Anil
%A Marathe,Madhav V.
%A Parthasarathy,Srinivasan
%A Srinivasan, Aravind
%K cross-layer design
%K end-to-end scheduling
%K Interference
%K SINR model
%K Wireless networks
%X Recently, there has been substantial interest in the design of cross-layer protocols for wireless networks. These protocols optimize certain performance metric(s) of interest (e.g. latency, energy, rate) by jointly optimizing the performance of multiple layers of the protocol stack. Algorithm designers often use geometric-graph-theoretic models for radio interference to design such cross-layer protocols. In this paper we study the problem of designing cross-layer protocols for multi-hop wireless networks using a more realistic Signal to Interference plus Noise Ratio (SINR) model for radio interference. The following cross-layer latency minimization problem is studied: Given a set V of transceivers, and a set of source-destination pairs, (i) choose power levels for all the transceivers, (ii) choose routes for all connections, and (iii) construct an end-to-end schedule such that the SINR constraints are satisfied at each time step so as to minimize the make-span of the schedule (the time by which all packets have reached their respective destinations). We present a polynomial-time algorithm with provable worst-case performance guarantee for this cross-layer latency minimization problem. As corollaries of the algorithmic technique we show that a number of variants of the cross-layer latency minimization problem can also be approximated efficiently in polynomial time. Our work extends the results of Kumar et al. (Proc. SODA, 2004) and Moscibroda et al. (Proc. MOBIHOC, 2006). Although our algorithm considers multiple layers of the protocol stack, it can naturally be viewed as compositions of tasks specific to each layer --- this allows us to improve the overall performance while preserving the modularity of the layered structure.
%B Proceedings of the 8th ACM international symposium on Mobile ad hoc networking and computing
%S MobiHoc '07
%I ACM
%C New York, NY, USA
%P 110 - 119
%8 2007///
%@ 978-1-59593-684-4
%G eng
%U http://doi.acm.org/10.1145/1288107.1288123
%R 10.1145/1288107.1288123
%0 Journal Article
%J Proceedings of the IEEE
%D 2006
%T Wireless Network Security and Interworking
%A Shin,M.
%A Ma,J.
%A Mishra,A.
%A Arbaugh, William A.
%K 3G mobile communication
%K 3G systems
%K Authentication
%K Bandwidth
%K Communication system security
%K computer network security
%K computer security
%K Data security
%K internetworking
%K Land mobile radio cellular systems
%K Paper technology
%K security architectures
%K security of data
%K telecommunication security
%K wireless communication
%K wireless communications
%K Wireless LAN
%K wireless network security
%K Wireless networks
%K wireless technologies
%K WLAN systems
%X A variety of wireless technologies have been standardized and commercialized, but no single technology is considered the best because of different coverage and bandwidth limitations. Thus, interworking between heterogeneous wireless networks is extremely important for ubiquitous and high-performance wireless communications. Security in interworking is a major challenge due to the vastly different security architectures used within each network. The goal of this paper is twofold. First, we provide a comprehensive discussion of security problems and current technologies in 3G and WLAN systems. Second, we provide introductory discussions about the security problems in interworking, the state-of-the-art solutions, and open problems.
%B Proceedings of the IEEE
%V 94
%P 455 - 466
%8 2006/02//
%@ 0018-9219
%G eng
%N 2
%R 10.1109/JPROC.2005.862322
%0 Conference Paper
%B Proceedings of the 2005 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
%D 2005
%T Algorithmic aspects of capacity in wireless networks
%A Kumar,V. S. Anil
%A Marathe,Madhav V.
%A Parthasarathy,Srinivasan
%A Srinivasan, Aravind
%K capacity modeling
%K end-to-end scheduling
%K Linear programming
%K Wireless networks
%X This paper considers two inter-related questions: (i) Given a wireless ad-hoc network and a collection of source-destination pairs {(si,ti)}, what is the maximum throughput capacity of the network, i.e. the rate at which data from the sources to their corresponding destinations can be transferred in the network? (ii) Can network protocols be designed that jointly route the packets and schedule transmissions at rates close to the maximum throughput capacity? Much of the earlier work focused on random instances and proved analytical lower and upper bounds on the maximum throughput capacity. Here, in contrast, we consider arbitrary wireless networks. Further, we study the algorithmic aspects of the above questions: the goal is to design provably good algorithms for arbitrary instances. We develop analytical performance evaluation models and distributed algorithms for routing and scheduling which incorporate fairness, energy and dilation (path-length) requirements and provide a unified framework for utilizing the network close to its maximum throughput capacity.Motivated by certain popular wireless protocols used in practice, we also explore "shortest-path like" path selection strategies which maximize the network throughput. The theoretical results naturally suggest an interesting class of congestion aware link metrics which can be directly plugged into several existing routing protocols such as AODV, DSR, etc. We complement the theoretical analysis with extensive simulations. The results indicate that routes obtained using our congestion aware link metrics consistently yield higher throughput than hop-count based shortest path metrics.
%B Proceedings of the 2005 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
%S SIGMETRICS '05
%I ACM
%C New York, NY, USA
%P 133 - 144
%8 2005///
%@ 1-59593-022-1
%G eng
%U http://doi.acm.org/10.1145/1064212.1064228
%R 10.1145/1064212.1064228
%0 Journal Article
%J IEEE Wireless Communications
%D 2004
%T Proactive key distribution using neighbor graphs
%A Mishra,A.
%A Min Ho Shin
%A Petroni,N. L.
%A Clancy,T. C
%A Arbaugh, William A.
%K access points
%K Authentication
%K authentication time
%K Base stations
%K Communication system security
%K Delay
%K graph theory
%K GSM
%K IEEE 802.11 handoff
%K Land mobile radio cellular systems
%K Message authentication
%K mobile radio
%K Multiaccess communication
%K neighbor graph
%K Network topology
%K Roaming
%K telecommunication security
%K Telephone sets
%K user mobility
%K Wi-Fi networks
%K wireless data networks
%K Wireless LAN
%K Wireless networks
%X User mobility in wireless data networks is increasing because of technological advances, and the desire for voice and multimedia applications. These applications, however, require that handoffs between base stations (or access points) be fast to maintain the quality of the connections. In this article we introduce a novel data structure, the neighbor graph, that dynamically captures the mobility topology of a wireless network. We show how neighbor graphs can be utilized to obtain a 99 percent reduction in the authentication time of an IEEE 802.11 handoff (full EAP-TLS) by proactively distributing necessary key material one hop ahead of the mobile user. We also present a reactive method for fast authentication that requires only firmware changes to access points and hence can easily be deployed on existing wireless networks.
%B IEEE Wireless Communications
%V 11
%P 26 - 36
%8 2004/02//
%@ 1536-1284
%G eng
%N 1
%R 10.1109/MWC.2004.1269714
%0 Journal Article
%J IEEE Security & Privacy
%D 2003
%T The dangers of mitigating security design flaws: a wireless case study
%A Petroni,N. L.
%A Arbaugh, William A.
%K Communication system security
%K computer security
%K cryptography
%K design flaw mitigation
%K Dictionaries
%K legacy equipment
%K privacy
%K Protection
%K Protocols
%K security design flaws
%K security of data
%K synchronous active attack
%K telecommunication security
%K Telecommunication traffic
%K wired equivalent privacy protocol
%K Wireless LAN
%K wireless local area networks
%K Wireless networks
%X Mitigating design flaws often provides the only means to protect legacy equipment, particularly in wireless local area networks. A synchronous active attack against the wired equivalent privacy protocol demonstrates how mitigating one flaw or attack can facilitate another.
%B IEEE Security & Privacy
%V 1
%P 28 - 36
%8 2003/02//Jan
%@ 1540-7993
%G eng
%N 1
%R 10.1109/MSECP.2003.1176993