Abstract We develop an on‐demand, multipath distance vector routing protocol for mobile ad hoc networks. Specifically, we propose extensions to a well‐studied single path known as on‐demand (AODV). The resulting is referred (AOMDV). guarantees loop freedom and disjointness of alternate paths. Performance comparison AOMDV with AODV using ns‐2 simulations shows that able effectively cope mobility‐induced route failures. In particular, it reduces the packet loss by up 40% achieves remarkable...

We conduct the first detailed measurement analysis of network resource usage and subscriber behavior using a large-scale data set collected inside nationwide 3G cellular network. The tracks close to million subscribers over thousands base stations. analyze individual behaviors observe significant variation in among subscribers. characterize mobility temporal activity patterns identify their relation traffic volume. then investigate how efficiently radio resources are used by different as...

In this paper, we consider multihop wireless mesh networks, where each router node is equipped with multiple radio interfaces, and channels are available for communication. We address the problem of assigning to communication links in network objective minimizing overall interference. Since number radios on any can be less than channels, channel assignment must obey constraint that different assigned incident at most interfaces node. The above optimization known NP-hard. design centralized...

Conventional static datacenter (DC) network designs offer extreme cost vs. performance tradeoffs---simple leaf-spine networks are cost-effective but oversubscribed, while "fat tree"-like solutions good worst-case expensive. Recent results make a promising case for augmenting an oversubscribed with reconfigurable inter-rack wireless or optical links. Inspired by the promise of reconfigurability, this paper presents FireFly, solution that pushes DC design to on three key fronts: (1) all links...

In overdeployed sensor networks, one approach to conserve energy is keep only a small subset of sensors active at any instant. We consider the problem selecting minimum size connected K-cover, which defined as set M such that each point in network "covered" by least K different M, and communication graph induced connected. For above optimization problem, we design centralized approximation algorithm delivers near-optimal (within factor O(lg n)) solution, present distributed version...

In this paper, we consider multi-hop wireless mesh networks, where each router node is equipped with multiple radio interfaces and channels are available for communication. We address the problem of assigning to communication links in network objective minimizing overall interference. Since number radios on any can be less than channels, channel assignment must obey constraint that different assigned incident atmost node. The above optimization known NP-hard. design centralized distributed...

Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability multiple mobile broadband technologies, together with increasing use real-time multimedia applications, creating strong demand handover solutions that can seamlessly and securely transition user sessions across technologies. A challenge meeting this growing ensure performance, measured in terms latency loss. In addition, must...

We propose a novel algorithm for detecting worm-hole attacks in wireless multi-hop networks. The uses only connectivity information to look forbidden substructures the graph. proposed approach is completely localized and, unlike many techniques literature, does not use any special hardware artifact or location information, making technique universally applicable. independent of communication models. However, knowledge model and node distribution helps estimate parameter used algorithm....

In this work, we investigate the use of directional antennas and beam steering techniques to improve performance 802.11 links in context communication between amoving vehicle roadside APs. To end, develop a framework called MobiSteer that provides practical approaches perform steering. can operate two modes - cached mode where it uses prior radiosurvey data collected during "idle" drives, online mode, probing. The goal is select best AP combination at each point along drive given available...

Accurate interference models are important for use in transmission scheduling algorithms wireless networks. In this work, we perform extensive modeling and experimentation on two 20-node TelosB motes testbeds -- one indoor the other outdoor to compare a suite of their accuracies. We first empirically build validate physical model via packet reception rate vs. SINR relationship using measurement driven method. then similarly instantiate simpler models, such as hop-based, range-based, protocol...

We consider the channel assignment problem in a multi-radio wireless mesh network that involves assigning channels to radio interfaces for achieving efficient utilization. propose notion of traffic-independent base ease coordination and enable dynamic, flexible assignment. present novel formulation as topology control problem, show resulting optimization is NP-complete. then develop new greedy heuristic algorithm (termed CLICA) finding connected, low interference topologies by utilizing...

Data caching can significantly improve the efficiency of information access in a wireless ad hoc network by reducing latency and bandwidth usage. However, designing efficient distributed algorithms is nontrivial when nodes have limited memory. In this article, we consider cache placement problem minimizing total data cost networks with multiple items memory capacity. The above optimization known to be NP-hard. Defining benefit as reduction cost, present polynomial-time centralized...

In this paper, we propose two new MAC protocols for multichannel operation in wireless ad hoc and mesh networks. The first protocol, extended receiver directed transmission protocol (xRDT) is based on a previously known solution called (RDT) that uses notion of quiescent channel. xRDT solves the problems faced by RDT, such as hidden terminal deafness, using an additional busy tone interface few operations. We also develop novel single solution, local coordination-based (LCM MAC). LCM...

With the proliferation of WiFi technology, many networks are accessible from vehicles on road making vehicular access realistic. However, several challenges exist: long latency to establish connection a point (AP), lossy link performance, and frequent disconnections due mobility. We argue that people drive familiar routes frequently, thus mobility connectivity related information along their drives can be predicted with good accuracy using historical - such as GPS tracks timestamps, RF...

We consider the problem of localizing a wireless client in an indoor environment based on signal strength its transmitted packets as received stationary sniffers or access points. Several state-of-the-art localization techniques have drawback that they rely extensively labor-intensive 'training' phase does not scale well. Use unmodeled hardware with heterogeneous power levels further reduces accuracy these techniques.

360° videos provide an immersive experience to users, but require considerably more bandwidth stream compared regular videos. State-of-the-art video streaming systems use viewport prediction reduce requirement, that involves predicting which part of the user will view and only fetching content. However, is error prone resulting in poor Quality Experience (QoE). We design PARSEC, a system reduces requirement while improving quality. PARSEC trades off for additional client-side computation...

In the recent past, there has been a tremendous increase in popularity of VoIP services as result huge growth broadband access. The same voice-over-Internet protocol (VoIP) service poses new challenges when deployed over wireless mesh network, while enabling users to make voice calls using WiFi phones. Packet losses and delay due interference multiple-hop network with limited capacity can significantly degrade end-to-end call quality. this work, we discuss basic requirements for efficient...

We have designed and evaluated iMesh, an infrastructure-mode 802.11-based mesh network. IEEE 802.11 access points double as routers making the network architecture completely transparent to mobile clients, who view a conventional wireless LAN. Layer-2 handoffs between trigger routing activities inside network, which can be thought of layer-3 handoffs. describe design rationale testbed implementation iMesh. present results related handoff performance. The demonstrate excellent performance,...

We present a practical, measurement-based model that captures the effect of interference in 802.11-based wireless LAN or mesh networks. The goal is to capacity any given link presence number interferers deployed network, carrying specified amount offered load. Central our modeling approach MAC-layer for 802.11 fed by PHY-layer models deferral and packet capture behaviors, which turn are profiled based on measurements. target network be evaluated needs only O(N) measurement steps gather...

We perform a head-to-head comparison of the performance characteristics 3G network operated by nation-wide provider and metro-scale WiFi commercial ISP, from perspective vehicular access. Our experience shows that over wide geographic region under mobility, these networks exhibit very different throughput coverage characteristics. has frequent disconnections even in commercially operated, deployment; but when connected, indeed delivers high throughputs mobile scenario. The offers similar or...

One of the useful approaches to exploit redundancy in a sensor network is keep active only small subset sensors that are sufficient cover region required be monitored. The set should also form connected communication graph, so they can autonomously respond application queries and/or tasks. Such known as cover, and problem selecting minimum has been well studied when transmission radius sensing each fixed. In this article, we address energy-cost node vary its radius; larger or entails higher...

Conventional static datacenter (DC) network designs offer extreme cost vs. performance tradeoffs---simple leaf-spine networks are cost-effective but oversubscribed, while "fat tree"-like solutions good worst-case expensive. Recent results make a promising case for augmenting an oversubscribed with reconfigurable inter-rack wireless or optical links. Inspired by the promise of reconfigurability, this paper presents FireFly, solution that pushes DC design to on three key fronts: (1) all links...

We describe an end-to-end platform called SpecSense to support large scale spectrum monitoring. crowdsources monitoring low-cost, low-power commodity SDR/embedded platforms and provides necessary analytics in a central server. In this work, we address specific challenges related accurately estimate occupancy on demand with low overhead. To the accuracy question, augment state-of-the-art spatial interpolation techniques accommodate scenarios where RF propagation characteristics change across...

Networks of small, densely distributed wireless sensor nodes are capable solving a variety collaborative problems such as monitoring and surveillance. We develop simple algorithm that detects tracks moving target, alerts along the projected path target. The involves only computation localizes communication to in vicinity target its course. is evaluated on small-scale testbed Berkeley motes using light source performance results presented emphasizing accuracy technique, with discussion about...