Çankaya GCRIS Standart veritabanının içerik oluşturulması ve kurulumu Research Ecosystems (https://www.researchecosystems.com) tarafından devam etmektedir. Bu süreçte gördüğünüz verilerde eksikler olabilir.
Browsing Elektronik ve Haberleşme Mühendisliği Bölümü by Department "Çankaya Üniversitesi, Mühendislik Fakültesi, Elektronik ve Haberleşme Mühendisliği Bölümü"
Cognitive Radio (CR) has appeared as one of the solutions to mitigate the spectrum scarcity problem. One of areas that has suffered from spectrum scarcity is Wireless Body Area Networks (WBAN). It is possible to use CR with an adaptive power control and transmit scheme over the same channel as a licensed user. This is called the underlay approach. Since the number of applications that use the unlicensed bands is rapidly increasing, it is important to devise methods that utilize licensed bands without causing problems to the licensed user. Utilizing underlay CR in WBAN applications may help resource constrained sensors to operate even in cases where unlicensed bands are full. Another problem is the limited lifetime of sensors. Recently, energy harvesting has emerged as a topic of much attention to increase the lifetime of sensors. CR-WBANs can help us to build a healthcare system that is more reliable and efficient than traditional WBANs; however, many challenges still need to be investigated. In this thesis, we examine the minimum required power that must be transmitted from a specialized device called the hybrid access point (HAP) to have the network running indefinitely. A HAP is used both to transfer energy to the sensors and to gather sensor data and forward it to the higher layer in the WBAN.