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Distributed spectrum sensing (DSS) enables a Cognitive Radio (CR) network to reliably detect licensed users and avoid causing interference to licensed communications. The data fusion technique is a key component of DSS. We discuss the Byzantine failure problem in the context of data fusion, which may be caused by either malfunctioning sensing terminals or(More)
Establishing a control channel for medium access control is a challenging problem in multi-channel and dynamic spectrum access (DSA) networks. In the design of multi-channel MAC protocols, the use of channel (or frequency) hopping techniques (a.k.a. parallel rendezvous) have been proposed to avoid the bottleneck of a single control channel. In DSA networks,(More)
In decentralized cognitive radio (CR) networks, establishing a link between a pair of communicating nodes requires that the radios "rendezvous” in a common channel-such a channel is called a rendezvous channel-to exchange control information. When unlicensed (secondary) users opportunistically share spectrum with licensed (primary or incumbent)(More)
—In decentralized cognitive radio (CR) networks, enabling the radios to establish a control channel (i.e., " rendezvous " to establish a link) is a challenging problem. The use of a dedicated common control channel simplifies the rendezvous process but may not be feasible in many opportunistic spectrum sharing scenarios due to the dynamically changing(More)
In cognitive radio (CR) networks, a pair of CR nodes have to ``rendezvous'' on a common channel for link establishment. Channel hopping (CH) protocols have been proposed for creating rendezvous over multiple channels to reduce the possibility of rendezvous failures caused by the detection of primary user signals. Rendezvous within a minimal bounded time(More)
—In Cognitive Radio (CR) networks, establishing a link between a pair of communicating nodes requires that their radios are able to " rendezvous " on a common channel (a.k.a. a rendezvous channel). When unlicensed (secondary) users opportunistically share spectrum with licensed (primary or incumbent) users, a given rendezvous channel may become unavailable(More)
The lack of floor plans is a critical reason behind the current sporadic availability of indoor localization service. Service providers have to go through effort-intensive and time-consuming business negotiations with building operators, or hire dedicated personnel to gather such data. In this paper, we propose Jigsaw, a floor plan reconstruction system(More)
Existing code designs for display-camera based visual communication all have an all-or-nothing behavior, i.e., they assume the entire code must be decoded. However, diverse operational conditions due to device hardware diversity (in camera resolution and frame rate) and distance range motivate more scalable designs. In this paper, we borrow the notion of(More)
As children increasingly use the Internet, there have been mounting concerns about their privacy online. As a result, the U.S. Congress enacted the Children's Online Privacy Protection Act (COPPA) to prohibit websites from collecting information from children under 13 years of age without verifiable parental consent. Unfortunately, few technologies are(More)