Application Mobilization, or the ability of an enterprise employee to rely on mobile devices such as smartphones and tablets, to continue to perform business workflows even when mobile, is seen as a game changer to improve productivity. However, the practical adoption of enterprise mobility is very much in its in fancy, and seemingly has barriers. We posit that these barriers include heavy user-burden in accomplishing tasks (e.g. number of actions required to execute a workflow), high cost of mobile access (e.g. latency for content fetching), and irrelevance of available mobile functions (e.g. mobile app defeaturization done inappropriately).The novelty of our research is in a unified observe-patternize-mimic paradigm we explore to address these barriers, based on a simple question: could patterns in user-behavior be learned, and leveraged for reducing user-burden? If patterns are discovered, then we show that intelligent mimicking of these patterns at appropriate junctures can considerably relieve the mobile user burden. We motivate this paradigm through three application scenarios representing read, write, and act usage modalities.

Cochannel links in a Wireless LAN are separated across orthogonal time slots to avoid interference. With increasing density of links, time sharing the channel leads to severe capacity problems. In this paper, we identify a specific class of interference scenarios called asymmetric interference scenarios, where the nature of interference is different at the receivers of the concurrent signals. We show that, with appropriate handling, asymmetric interference allows each receiver to decode its intended reception successfully. We represent the signal combination at the receiver as a function fc and propose a solution called Symbiotic Coding (SC) such that fc(E1(d1;d2);E2(d1; d2)) is equal to E1(d1;d2), where d1and d2are the intended and interfering data symbol sequences and E1is the encoder at sender 1 and E2at sender 2, respectively. SC, thus, enables successful simultaneous cochannel transmissions even if they result in a collision. The performance of SC scales with the number of interfering links achieving median throughput improvements of 30 and 86 percent over time sharing with two and three interfering links, respectively. We address fundamental challenges in realizing SC including synchronization, coding algorithms, extensions to different modulations. We also implement SC on software defined radios and demonstrate its practical feasibility.

While a remote computing solution such as VNC is an effective technology for PC users to access a remote computer, it is not as effective while being used from smartphones. In this paper, we propose techniques to improve remote computing from smartphones that help deliver near-PC level experience to users. We introduce a key building block called smart-macros that have the robustness of application macros but at the same time possess the generality of raw macros. Using smart-macros we design and prototype SmartVNC, a remote computing solution for smartphones. We show using experimental studies and a trace based analysis of real user activity, that SmartVNC can improve user experience considerably.

In this paper, we focus on securing communication over wireless data networks from malicious eavesdroppers by using smart antennas. While conventional cryptography-based approaches focus on hiding the meaning of the information being communicated from the eavesdropper, we consider a complimentary class of strategies that limit knowledge of the existence of the information from the eavesdropper. We profile the performance achievable with simple beamforming strategies using a newly defined metric called exposure region. We then present three strategies within the context of an approach calledAegis, which uses virtual arrays of physical arrays to significantly improve the exposure region performance of a wireless LAN environment. Using simulations, analysis, and field trials, we validate and evaluate the proposed strategies.

Most mobile devices today are equipped with multiple and heterogeneous wireless interfaces. In this paper we ask the following question: what is the best approach to leverage the multiple interfaces available at a mobile device in terms of the performance delivered to the user? In answering the question we argue that simple "bandwidth aggregation" approaches do not provide any meaningful benefits when the multiple interfaces used have highly disparate bandwidths as is true in many practical environments. We then present super-aggregation, a set of mechanisms that in tandem use the multiple interfaces intelligently and in the process is able to achieve a performance that is "better than the sum of throughputs" achievable through each of the interfaces individually. We prototype super-aggregation on both a laptop and the Google Android mobile phone and demonstrate the significant (up to 3x throughput) performance improvements it provides in real-world experiments.

In this paper, we focus on securing communication over wireless data networks from malicious eavesdroppers, using smart antennas. While conventional cryptography based approaches focus on hiding the meaning of the information being communicated from the eavesdropper, we consider a complimentary class of strategies that limit knowledge of the existence of the information from the eavesdropper. We profile the performance achievable using simple beamforming strategies using a newly defined metric called exposure region. We then present three strategies within the context of an approach called virtual arrays of physical arrays to significantly improve the exposure region performance of a wireless LAN environment. Using simulations and analysis, we validate and evaluate the proposed strategies.

The expected VoIP call capacity in a one hop IEEE 802.11b network with G.711 voice codec is about 85 simultaneous calls, but the actual observed capacity is only 5 calls even at the highest data rate and under zero loss conditions. In this paper we analyze the reasons behind this inferior performance of VoIP traffic. We also present algorithms at the medium access control layer to improve the observed call capacity. Finally, using ns-2 based simulations, we evaluate the algorithms and show that performance improvements of up to 300% can be achieved.

In this paper, we model the link duration of the random waypoint model for mobile ad hoc networks. The link duration is the time interval in which two nodes stay within transmission range of each other. We find that link duration is determined by the relative speed and active distance between two nodes, which are in turn determined by the angles of the two nodes' velocities and the incident angle of one node to the other node's transmission range. We derive the probability distribution function of link duration for the random waypoint model and verify the analytical result via simulations. The result show that the analytical and simulation curves match very well