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Research communities have recently focused on the issues related with the internal interference in homogeneous IEEE 802.15.4 Wireless Body Sensor Networks (WBSNs). Frequency-hopping strategies seem to be an effective way to reduce the destructive impact of internal interference on WBSN performance. However, this strategy has its limitations. In this paper, a new strategy called “phase-adjustment”...
IEEE 802.15.4 is arguably considered as a well designed standard protocol to address the need for low-rate, low-power and low-cost Wireless Body Sensor Networks (WBSNs). Within a WBSN, Node's communication occurs during their confined active periods. The increase in number of active WBSNs would consequently result in the elevation of the overlapping ratio between the active periods of neighbouring...
One of the crucial issues with IEEE 802.15.4-based wireless body sensor networks operating in the unlicensed 2.4 GHz band is to maintain reliable transmission while being subjected to external interference (i.e. WiFi). One approach to mitigate this problem is to enable body sensor networks to adaptively change their current frequency channel and to change the transmit-power in response to the observed...
The IEEE 802.15.4 standard is an interesting technology for use in mobile body sensor networks (MBSN), where entire networks of sensors are carried by humans. In many environments the sensor nodes experience external interference – for example, when the BSN is operated in the 2.4GHz ISM band and the human moves in a densely populated city, it will likely experience WiFi interference, with a quickly...
One of the main problems affecting reliable transmission in wireless body sensor networks based on IEEE 802.15.4 is interference caused by sharing the unlicensed 2.4 GHz ISM band with other technologies such as Wifi. One possible approach to deal with this problem is to allow a body sensor network to change its operating frequency and its transmit power in response to changes in the observed interference...
Mobile Wireless Sensor Networks (MWSN) are becoming increasingly common these days and are hugely used in different applications like remotely monitoring health of patients, wild life tracking, localization and target tracking. In all these applications, mobile sensor nodes associate and communicate with different fixed coordinators. Reliable data transmission, maintaining an acceptable level of resiliency,...
The duration time spent by end devices in orphan state in beacon-enabled IEEE 802.15.4 networks has a direct relationship with their energy consumption. The latency experienced for performing a coordinator discovery process and a successful association is related to such factors as beacon interval length, channel interference, message signaling, etc. To mitigate the overall energy consumption of the...
The impact of shared frequency spectrum on performance of Radio Frequency (RF) technologies such as Wireless Body Sensor Networks (WBSNs), have recently brought a serious attention among computer scientists. In this study, the impact of channel scarcity on WBSN performance is investigated from various points of view, Spectrum utilization level, orphan scanning duration, packet loss and total energy...
The channel scarcity phenomenon has recently introduced new challenges in the field of Wireless Body Sensor Networks (WBSNs). Within a WBSN, node's communication is restricted throughout their defined active period. As the number of WBSNs increases, the overlapping active periods are elevated due to inefficient utilization of the spectrum. This consequently results in higher packet loss ratio and...
In this paper, we investigate passive discovery of IEEE 802.15.4-based Body Sensor Networks (BSNs). BSNs are wearable networks that monitor the vital functions of the body while the person can roam around freely. One challenging task that BSNs has to perform is the discovery of certain coordinator nodes, for example gateways towards data processing and storage services. We are presenting a cooperative...
In this paper we propose a new framework for multi-class face recognition based on combination of support vector machine (SVM) and non-parametric discriminant analysis (NDA). SVM fully describes the decision surface by incorporating local information in the linear space. On the other hand, NDA is a non-parametric improvement over linear discriminant analysis that traditionally suffered from a fundamental...
EML-MAC is a new TDMA based Medium Access Control MAC protocol designed to improve the energy efficiency of the WSN nodes by improving the time slot synchronization algorithm for ML-MAC. The proposed slot assignment algorithm reduces duplicate slot assignment by reducing slot collision. This reduces the duty cycle of the transceiver by improving the handshaking process and reducing the number of transition...
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