The primary aim of this research is to design a flexible UWB and WSN integrated architecture, which could be used effectively in all kind of WSNs. From the recent study, it was observed that most of the advanced issues with the Wireless Sensor Network are related to Physical and Radio layers. The MAC’s compatibility with the physical layer and low duty cycle scheduling are the essentials for a WSN. These concerns are used as starting point of the research. The Doctoral Thesis has not only thoroughly investigated the root causes but designed a flexible framework, which can be employed in both small and dense network. Thesis is mainly focused on two areas, MAC architecture, and PHY layer design. The Doctoral Thesis uses Agile approach where all the main identified issues are divided in sprints, and each sprint is resolved separately. On the resolution of individual sprints. All issues are jointly retested. At the end of research architecture is used on a hardware platform under a WBAN project “SMART Incubator”. This over five-year long research has proved that the UWB is the most practical solution for wireless sensor network if it is used under the parameters of our given framework.