Recently, user demand for diverse data services in mobile communication networks has gradually increased. However, bandwidth is limited and conventional mobile communication systems have not accommodated this increasing user demand for diverse data services. In 2002, Federal Communications Commission(FCC) set a license-free bandwidth from 3.1 GHz to 10.6 GHz with a strict emmision rule for ultra-wideband(UWB) communications. The bandwidth of UWB is much wider than those of conventional mobile communication systems and UWB systems are considered as a solution for accommodating the increasing user demand for diverse data services.
In this thesis, UWB physical layer techniques in a radio access network are proposed and evaluated in terms of throughput and user capacity. Specially, random and orthogonal hopping multiple access techniques in an OFDM based Multi-band UWB system are proposed and the statistical multiplexing effect is analyzed. Coverage expansion techniques in a multi-user environment are also proposed and analyzed. Simulation results show that the random hopping multiple access technique which has statistical multiplexing gain performs better in a low activity environment and the orthogonal hopping multiple access technique performs better in a high activity environment. The proposed UWB physical layer techiques can be utilized in designing a UWB radio access network.
