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We1 propose two methods for the detection of RF interference. The first one is for the detection of the interferences from microwave ovens, and the second one is for Wi-Fi and Bluetooth signals. The motivation of this work is to design a system for reliable wireless communication. Specifically, the systems equipped with interference detectors will be able to choose the appropriate time intervals to...
Dynamic transmit-power control (DTPC) is critical to improve spectral efficiency and reduce interference in wireless local area networks (WLANs). DTPC schemes typically use signal-to-noise-ratio (SNR) information and require exchange of information between transmitters and receivers. However, that is not always easy to implement in actual WLAN deployments. In this paper, we present a simple but novel...
We study the resource allocation and management issues related to heterogeneous wireless systems made up of several Radio Access Technologies (RATs) that collectively provide a unified wireless network to a diverse set of users through co-ordination managed by a centralized Global Resource Controller (GRC). We assume that the user devices are multi-modal, which makes it possible for each device to...
Transmission Opportunity (TXOP) which is specified in the IEEE 802.11e enables a Wi-Fi station to transmit multiple frames consecutively. In this paper, we propose an adaptive transmission scheme based on the Dynamic Aggregation and Fragmentation (DAF) algorithm. With real-time scheduling and adaptive TXOP allocation being the main focus of the suggested adaptive transmission scheme, optimum transmission...
Most studies on performance of IEEE 802.11 distributed coordination function (DCF) have proved that the binary exponential backoff (BEB) algorithm suffers from low throughput, long transmission delays and low transmission reliability, for a high traffic load. In this paper, we propose a two-phase contention window (TPCW) access mechanism that enhances the aggregate throughput and transmission reliability...
Distributed Coordination Function (DCF) is a well-known MAC protocol for single channel wireless ad-hoc networks. However, hidden terminal and false blocking problems may happen if DCF is directly applied to multi-channel environments. As a result, the paper proposes a Multi-group Multipipeline Multi-channel MAC protocol (3M MAC) for wireless multi-channel ad-hoc networks to avoid multi-channel hidden...
In this paper, we investigate scenarios where 4G LTE base stations are mounted on balloons raised in the sky for the provision of cellular connectivity and coverage within an area of few kilometers (e.g., scenarios for emergency communications). In this context, the link between the base stations need to be completed using wireless technologies, thus impacting the performance of the X2 logical interface...
Heterogeneous networks are expected to play a major role towards meeting the exploding traffic demand over cellular systems. Particularly, existing WiFi hotspots will be dynamically utilized to offload the traffic of cellular mobile subscribers. This will be further facilitated by forthcoming advances in mobile device capabilities that will include the ability to operate multiple wireless interfaces...
This paper tackles the WiFi hotspot deployment problem in a metropolitan area by leveraging mobile users' context, i.e., their trajectories and scenario interaction. The careful deployment of hotspots in such areas allow to maximize WiFi offloading, a viable solution to the recent boost up of mobile data consumption. Our proposed strategy considers the restrictions imposed by transportation modes...
WiFi access points (APs) are nowadays ubiquitous in multi-level buildings to provide uninterrupted network access to mobile users. WiFi signals are the widely recognized option to provide feasible indoor positioning system (IPS). However majority of IP research concentrates on 2D positioning compared to vertical or floor level determination. To date the most reliable floor determination techniques...
The tremendous increase in the mobile data traffic has led the network operators to use offloading solutions in Radio Access Technologies (RATs) such as WiFi or smallcells. However, these solutions are not efficient since none of them controls the offloading from a centralized global network view. Current offloading methods are mostly user-based and they do not completely consider the user satisfaction,...
The peer-to-peer and ad-hoc networking allows content dissemination and sharing among mobile devices without depending on any infrastructure. However, mobile devices still encounter content sharing issues in highly dense networks. Therefore, we develop a new architecture which creates self-organizing ad-hoc network with content centric networking over Wi-Fi Direct on smartphones. It enables nodes...
With Internet of Things (IoT) vision, computing systems get the ubiquity of real world. Wireless Sensor Network (WSN) technology plays a critical role for the construction of this paradigm. Reliable communication between WSN nodes and outside Internet entities will be needed for remote management of Internet Objects. On the other hand, low bandwith, high delay and packet error rates of the underlying...
Small-scale multicopters operating as autonomous teams in the air are envisioned for aerial monitoring and transport of goods in a variety of applications, including disaster management and environmental monitoring. For such applications to become reality, a high-throughput wireless network is needed. This paper presents experimental performance results with commercially available quadrocopters communicating...
This work addresses the implications of using the Time-Division Unbalanced Carrier Sense Multiple Access (TDuCSMA) coordination function to support triple-play services. Firstly, the theoretical background of TDuCSMA is reported, presenting its advantages and discussing its full compliance with the IEEE 802.11 standard. Secondly, a prototype of TDuCSMA is discussed in details. Then, a set of experiments...
Currently, cellular operators are struggling to relieve congestion on their networks in the face of rapidly growing mobile data traffic. While deploying an increasing number of base stations is expected to mitigate the disproportion between user demand and available radio resources, this solution is costly and plagued with many practical challenges. An attractive alternative is to enable cellular...
This paper exploits smartphones to design a transportation activity survey system that investigates when, where and how people travel in an urban area. In such a system, the essential requirement is collecting and processing big data which will raise two critical issues, energy-conservation and scalability. To address the former issue, the GPS sleeping interval of a smart-phone is controlled by the...
This study is motivated by a plan to install a software-defined wireless local area network (SDWLAN) on campus, which possesses a desired property that both data flow and device behaviors can be software-definable. Because the installation involves hundreds of access points, we must conduct simulations beforehand to verify the design and scalability of the target system. However, existing SDN simulator...
Troubleshooting network problems on networked home devices is not easy, because most devices have insufficient computing power to run sophisticated diagnostic tools and have no user interfaces to debug the problem directly. We propose MoT, a network problem diagnosis platform that leverages the collaboration of smart objects, smartphones, and computers. We take advantage that recent devices have multiple...
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