The fundamental idea of a technology currently known as ultra wideband (UWB), can be tracked at the end of the 19th century to the spark-gap tests of Guglielmo Marconi. Producing and transmitting short - in UWB on a nanosecond scale - impulses in time domain, potentially offers high signal bandwidth and low complexity for a communication system. Despite the simplicity and other advantages, it was not until in the 21st century when the first global regulation concerning UWB was revealed, not to mention the first global standard relating to the impulse based UWB. In this paper, the first completed impulse radio UWB standard, IEEE 802.15.4a published in 2007, is investigated and few improvements are suggested together with simulation results to support the stated enhancements and the effects of them. The enhancement can be, for example, increased data rate or number of users and improved detection performance.