Deepti Kakkar

Spektrumsb nder sind die Kommunikationsautobahn der Natur, die heutzutage stark berlastet sind. Um dieses Problem zu l sen, wird eine dynamische Zuweisung des Spektrums in Erw gung gezogen, die die derzeitige feste Zuweisungspolitik ersetzt. Bei der dynamischen Zuteilung nutzen unlizenzierte Benutzer den Kanal, wenn dieser frei ist, und geben ihn sofort frei, wenn ein lizenzierter Benutzer zur ckkehrt. Handoff ist das Hauptmerkmal der dynamischen Frequenzzuteilungspolitik. Es wurde auch beobachtet, dass mehrere Handoffs die Dienstqualit t f r die unlizenzierten Benutzer verschlechtern k nnen. Aus diesem Grund k nnen verschiedene Optimierungsmethoden angewandt werden, um die bestm gliche Spektrumszuteilung w hrend des Handoffs zu erreichen, so dass den kognitiven Nutzern eine bessere Dienstqualit t bei gleichzeitiger Verbesserung der Spektrumsnutzung geboten werden kann. Das Handoff-Verfahren kann pro-aktiv oder reaktiv sein. Pro-aktiv besch ftigt sich haupts chlich mit der vorherigen Vorbereitung des Satzes der Zielkan le, w hrend reaktives Handoff ein On-Demand-Ansatz ist. Beide Arten haben ihre eigenen Vor- und Nachteile. Je nach Anwendung kann jede der bergabetechniken verwendet werden.

Spectrum bands are nature's communication highway which are highly congested now-a-days. To overcome this problem, dynamic allocation of spectrum is under consideration over the current fixed spectrum allotment policy. In dynamic allotment, unlicensed users will be using the channel, whenever they find the channel idle and will immediately vacate the channel if licensed user returns. Handoff is the main feature of dynamic spectrum allotment policy. Also, it has been observed that multiple handoffs may degrade the service quality given to the unlicensed users. For that reason, different optimization methods may be applied for achieving the best possible spectrum allotment during handover so that the better quality of service can be given to the cognitive users with the simultaneous improvement in spectrum utilization. The handoff procedure can be pro-active or reactive type. Pro-active mainly deals with the beforehand preparation of the set of the target channels, while reactive handoff is on-demand approach. Both the styles have their own pros and cons. Depending on the application, any of the handoff technique can be used.

The world is filled with lots and lots of data. Be it data in the form of pictures, statistical values, videos, music, words, etc. Traditionally human being is able to recognize and extract a meaningful pattern out of such data. But as the volume of data increases, it becomes impossible for a human being to extract it meaningfully. To get a meaning out of such bulk data, a set of tools are required with the help of which a machine can be taught to recognize the pattern and extract the information. The term machine learning came into existence. Time is an importantfactor when it comes to data where the sudden change in the values at a particular time can have a huge impact on the outcome. Smart forecasting tools powered by data science is necessary to successfully deal with capacity and strategic planning which is required to handle the scenario and save lives. The purpose of this book is to present an efficient model that can forecast the values more accurately in a particular field.