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Glapa S.,Ruckus Wireless
Electronics World | Year: 2012

Wi-Fi can be integrated into a cellular environment to provide additional bandwidth for mobile broadband. Wi-Fi offers a new approach for delivering increased capacity of the magnitude sufficient to deal with exploding mobile Internet bandwidth demand. The approach includes meshed Wi-Fi access points integrated with 3G/4G small-cell radios within a small form-factor device that can be installed closer to subscribers. Also included in this new approach is high-speed wireless backhaul within the 5GHz band along with a comprehensive network-wide element and service management at the edge of the mobile operator network. By relying on realtime, observed capacity on all 2.4 and 5GHz frequencies, backhaul links can be automatically moved to a better channel with less interference, thereby realizing higher data rates. Wi-Fi backhaul approach has proven to deliver reliable, carrier grade transport of 3G mobile data and circuit-switched voice traffic along with the prioritized transport of timing signals necessary for small cell network synchronization. Source

Lee J.,Cisco Systems | Mo J.,Yonsei University | Trung T.M.,Electronics and Telecommunications Research Institute | Walrand J.,University of California at Berkeley | So H.-S.W.,Ruckus Wireless
IEEE Transactions on Vehicular Technology | Year: 2010

Many incompatible wireless protocols proliferate in unlicensed bands, creating complex coexistence and connectivity problems. If the trend continues, such problems will continue to exist in future unlicensed bands. We take a different approach to spectrum sharing. Instead of proposing a distinct medium-access control (MAC) protocol for each type of application, we propose a family of parameterized MAC protocols called WiFlex, which can be tailored to different application needs, ranging from wireless sensors to media centers. However, these protocols allow communication and spectrum-sharing coordination among different types of devices. We envision this family to be based on a multichannel physical layer. The contributions of this paper include a novel asynchronous split phase (ASP) protocol with dynamic priority support, even in multiple-collision-domain environments. When links are bidirectional, WiFlex resolves the multichannel hidden-node problem, achieving collision-free data exchange in a multihop environment. ASP provides a mechanism for prioritization and fairness. The performance of the protocol is evaluated through analysis and simulation. The coexistence of heterogeneous devices and the support for different applications with high performance are demonstrated. © 2006 IEEE. Source

Chen W.-S.,National Dong Hwa University | Chen Y.-J.,Ruckus Wireless | Wu S.-Y.,National Dong Hwa University
IEEE Transactions on Parallel and Distributed Systems | Year: 2014

Enterprise RFID data management is highly challenging not only because of the huge volume of data from distributed sources, but particularly because of the dynamic nature of the reader inputs. With user-designated quality of service (QoS) requirements, the data management system must be able to dynamically detect the status changes of the RFID inputs and adjust the processing strategies for continuously maintaining the desired level of QoS. We propose a QoS-aware framework for modeling the enterprise data service problem, and for on-line adaptive processing of distributed RFID data streams. The data processing structure is modeled as a hierarchy of aggregation nodes in accordance with the structure of an organization. Leaf nodes correspond to the RFID streaming inputs. A set of aggregation/deaggregation operations is devised to adjust the processing granularity level based on QoS dynamics. A QoS constrained query issued at any aggregation node is parsed into an aggregation subtree rooted at that node. For QoS-aware processing of the query, several algorithms are designed to dynamically apply proper aggregation/deaggregation operations on selected nodes for raising or lowering the granularity levels or changing the aggregation methods. The goal is to continuously maintain the desired level of QoS under constant variation of the streaming data volume. Prototype development and extensive simulation show that our framework and techniques can handle highly varied RFID streaming inputs and continuously satisfy the QoS constraints. © 2013 IEEE. Source

Li Q.,Huazhong University of Science and Technology | Pandharipande A.,HIGH-TECH | Ting S.H.,Ruckus Wireless | Ge X.,Huazhong University of Science and Technology
Eurasip Journal on Wireless Communications and Networking | Year: 2015

In this paper, an interference channel with a cognitive relay (IFC-CR) is considered to achieve spectrum sharing between a licensed primary user and an unlicensed secondary user. The CR assists both users in relaying their messages to the respective receivers, under the constraint that the performance of the legacy primary user is not degraded. Without requiring any non-causal knowledge, the CR uses a successive interference cancellation to first decode the primary and secondary messages after a transmission phase. A power allocation is then performed to forward a linear weighted combination of the processed signals in the relaying phase. Closed-form expressions of the end-to-end outage probability are derived for both primary and secondary users under the proposed approach. Furthermore, by exploiting the decoded primary and secondary messages in the first phase, we propose the use of dirty paper coding (DPC) at CR to pre-cancel the interference seen at the secondary (or primary) receiver in the second phase, which results in a performance upper bound for the secondary (or primary) user without affecting the other user. Simulation results demonstrate that with a joint consideration of the power control at the secondary transmitter and the power allocation at CR, performance gains can be achieved for both primary and secondary users. © 2015, Li et al. Source

Lin C.-C.,Ruckus Wireless | Jin P.,Broadcom Corporation | Ziolkowski R.W.,University of Arizona
Microwave and Optical Technology Letters | Year: 2012

A planar tri-band near-field resonant parasitic (NFRP) antenna for multiple-input multiple-output (MIMO) applications in the WLAN 2.4/5.2/5.8 GHz bands is presented. The tri-band functionality is obtained by introducing three different resonant parasitic elements near a simple driven element. Good impedance matching, radiation efficiency, and antenna patterns are realized at each of the desired resonant frequencies. Experimental confirmation of the simulated performance is presented. It is demonstrated that an array of these tri-band NFRP antennas obtains good isolation between elements even with small spacing between them. Calculated envelope correlation values are less than 0.12 within the bands of interest. The design methodologies of the tri-band NFRP antenna and the corresponding MIMO array are detailed. © 2012 Wiley Periodicals, Inc. Source

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