This paper presents an updated survey on research related to ultra wideband (UWB) communications, particularly that of impulse radio (IR) technology. In addition to the research, we survey UWB physical layer specifications of the two existing standards-the IEEE 802.15.6-2012 and the IEEE 802.15.4-2015-as well as the leading global UWB spectrum regulatory limitations which have been updated recently. The latter standard including the UWB specifications was first published in 2007 and the latest revision dates to 2015. The focus in this paper is the period from 2007 to 2015. Our purpose is to provide an in-depth survey with a clearly specified topic together with the standard specifications and the related regulatory restrictions. Additionally, the last part of this paper discusses the possibilities of increasing the current IR-UWB data rates to meet increasing future demands.