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Existing topology controls enable wireless nodes to control parameters, such as adjusting the transmission power or switching operating modes between a sleep mode and an active mode, to achieve energy savings and prolong network lifetime. However, the topology controls assume that the operating frequency is fixed or can be changed in a narrow range of frequencies, thus the communication distance is...
Due to the wide use of Wi-Fi technology, recent customer electronics such as smart phone, digital TV, laptop, refrigerator, air conditioner, robot vacuum and etc. provide Wi-Fi communication including Wi-Fi Direct (Peer-to-Peer) communication. For a simple and easy connection management between a smart phone and DTV, near field communication (NFC) is recently introduced. When a user brings a smart...
The Wireless Signal Networks (WSNs) use the signal strength variation of wireless nodes in the host medium as the main indicator of events or physical property changes in the medium. With the concept and application of the Underground Wireless Signal Networks (UWSNs) where the host medium is a soil, the real-time global subsurface monitoring of wireless underground sensor networks can be achieved,...
An accurate and simple radio propagation model for underground low-power devices such as wireless sensor nodes is introduced and its performance is evaluated by real wireless sensor nodes. The proposed model describes underground radio signal propagation that is proportional to where represents the distance and represents the attenuation constant reflecting the...
In this work, an Adaptive Channel Hopping (ACH) mechanism for sensor networks is proposed to avoid interference from other sources and narrow-band jamming. Under unfavorable channel conditions, ACH lets sensors switch to a new operating channel. ACH reduces the channel scanning and selection latency by ordering available channels using link quality indicator measurements and weights. The proposed...
In this paper, a new spectrum management scheme for CRNs called Voluntary Spectrum Handoff (VSH) is introduced. The two mechanisms proposed under VSH estimate opportune times to initiate unforced spectrum handoff events to facilitate setup and signaling of alternative channels without having communication disruption, which occurs when a secondary user is forced out of an operating spectrum due to...
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