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Indoor localization becomes increasingly important as context-aware applications gain popularity in mobile users. A promising approach for indoor localization is to leverage the pervasive WiFi infrastructure via fingerprinting-based inference. However, a WiFi device must frequently scan for WiFi signals during localization, leading to high power consumption. Moreover, switching to the scanning mode...
We consider the problem of jointly allocating channel center frequencies and bandwidths for IEEE 802.11 wireless LANs (WLANs). The bandwidth used on a link affects significantly both the capacity experienced on this link and the interference produced on neighboring links. Therefore, when jointly assigning both center frequencies and channel widths, there is a trade-off between interference mitigation...
The metabolic disorder which entails the absent or reduced control of blood glucose in the body by means of insulin dependence (Type 1) or intolerance (Type 2) affected more than 366 million people in 2011. This represents an increase of 28% new cases in one year. Diabetes Mellitus has become the most common chronic diseases in nearly all countries, and continues to increase in numbers and significance,...
In this paper, we present a quantitative assessment of the performance of a Wi-Fi like system in TV white space and compare it with the traditional Wi-Fi system in the ISM band. Particular emphasis is given to the constraint on the aggregate secondary interference on TV reception, which is regarded as the premise of the link throughput analysis that followed. Numerical evaluation is performed over...
Techniques for coordinated use of WiFi and LTE radio links are developed for operator-managed multi-radio heterogeneous networks. In particular, we consider deployments based on integrated small cells with co-located WiFi and LTE interfaces, which allow for tighter coordination between the two interfaces especially when used together with WiFi/LTE capable client devices. The paper develops a utility...
ZigBee based smart meter communication system may suffer from severe interference from WiFi hot spots. To avoid the interference, smart meter communication systems can adopt a cognitive implementation strategy, while treating the WiFi system as primary user (PU) of the spectrum. In this paper, we investigate the performance of secondary system (SU) operating in an interweave fashion to explore the...
An increasing number of WiFi and Bluetooth terminals, tags, and other mobile devices drives a growing demand for integration and coexistence of these two technologies. This paper gives the preliminary results of WiFi positioning in a WiFi and Bluetooth coexistence environment. The received signal strength indication is introduced as an observation applied to our WiFi positioning. Then, we present...
Interference is one of the key factors impacting the performance and robustness of Wireless Sensor Networks (WSN) operation. For serious WSN applications, it is crucial that interference mitigation acts in a fast and reliable fashion. We describe an adaptive and distributed channel hopping scheme, HOPSCOTCH1. Our scheme is novel in the sense that (1) it is built on a lightweight yet accurate metric...
This paper looks at regulation for enhanced forms of carrier aggregation. The first objective of the paper is to provide a vision for carrier aggregation that goes beyond LTE-Advanced. Carrier aggregation as currently defined is envisaged as the aggregation of blocks from spectrum resources which are statically assigned to a mobile network operator. In the enhanced vision dynamic assignments, shared...
This paper aims to exploit spectrum white spaces in time-domain via the Dynamic Spectrum Access (DSA) technology. DSA relies on opportunistic access of licensed spectrum by unlicensed devices. Any “unlicensed-with-licensed” coexistence must ensure “safe” (i.e., un-interfered) communications for the incumbents, while achieving high spectrum-use efficiency for the secondary users. We propose a novel...
This paper presents a high level description of an LTE system operating in license exempt bands. Since wireless networks potentially using different air interfaces may operate in these bands, coexistence is a challenge that needs to be addressed. This paper focuses on non-coordinated mechanisms for secondary users coexistence, and introduces a coexistence gap based method for LTE to dynamically share...
Wireless technologies are well known to provide tremendous benefits to the healthcare sector. In the evaluation of the wireless technologies, ZigBee is found specifically suitable for monitoring due to its low cost, long battery life and widely accepted standard. But ZigBee uses the same ISM free band with other wireless techniques, such as Wi-Fi, which is also widely deployed in health care. The...
With the continuous increase in Mobile Data traffic, limited availability of wireless spectrum and increased pressure on unit costs, operators have been looking at heterogeneous network architectures as an opportunity to solve the capacity and cost issues of mobile networks. In this paper, we will address the expected growth in traffic, and how the use of a combination of macro, small 3G/4G cells...
In this paper, we present an analysis model for the estimation of channel utilization for IEEE 802.11 ad hoc networks under saturated conditions in the presence of hidden terminals. We give a way to calculate the saturated throughout of multi-hop scenario. The ns-2 simulation results show the effectiveness of our analytical approach.
With the unprecedented aging of population, chronic disease become a serious problem in modern medical area. Recent advances of wireless technology make the health monitoring in home to be more convenient for the chronic disease. Reducing the influence of the interference from the other wireless equipment is one of the most important problems in wireless physical parameter monitoring device in healthcare...
The number of wireless devices (smartphones, laptops, sensors) that use the 2.4 GHz ISM band is rapidly increasing. The most common communication system in this band is Wi-Fi (IEEE 802.11b/g/n). For that reason coexistence between Wi-Fi and other systems becomes more and more important. In this paper we have investigated the influence on Wi-Fi communication for different interference sources, i.e...
This paper analyzes the possibility to introduce a WiFi type of secondary network containing multiple secondary access points (SAPs) in TV bands. In particular, the analysis investigates the limitations of TV whitespace (TVWS) usage imposed by the aggregate interference of the secondary users towards the primary and secondary system, assuming different levels of penetration of the TVWS-operating technology...
To improve the receive ratio of MAC-level broadcasting and reduce the variability of the receive ratio, we propose a directional receiving method in addition to the broadcast RTS/CTS. In this method, the broadcast sender first transmits RTS to the broadcast receiver that is connected to the largest number of hidden terminals. Each broadcast receiver overhearing the RTS then activates one of its directional...
Severe unfairness and even complete starvation may occur when using TCP-like congestion control in IEEE 802.11-based Wireless Mesh Networks (WMNs). Indeed, IEEE 802.11 is inherently unfair; however, economies of scale make it the commonly used MAC protocol in WMNs. Moreover, TCP-like protocols do not account for links interdependency within a neighborhood. In WMNs, congestion should be mutually handled...
Opportunistic access of licensed spectrum using a cognitive radio network (CRN) is getting research attraction due to its ability to improve utilisation of this scarce resource without affecting the primary users (PUs). To improve wide acceptability of CRN, it must be equipped with efficient protocols to deal with multiple primary networks to provision QoS guarantee for demand-driven applications...
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