On the power spectrum density and parameter choice of multicarrier UWB communications

Recently, ultra wideband (UWB) communications have received increasing interest due to the high data rate achievable in a short distance. UWB communications can have strong interference mitigation capability. A multicarrier ultra wideband (MC-UWB) system has been introduced in (A.H. Tewfik, et al., (2002)) and (E. Saberinia, et al., (2002)). In the MC-UWB communication systems, multiple symbols are transmitted over different carriers simultaneously. The same symbol is retransmitted over different frequency bands by utilizing frequency hopping (FH) techniques. Frequency hopping and multicarrier technologies smooth the average power spectrum density of the system. In this paper, the expression of the power spectrum density of the MC-UWB system is derived. The radiated emission power for UWB communication systems is limited by the spectrum mask specified by wireless communication authorities, such as the federal communications commission (FCC) in United States. Different parameters in the MC-UWB system will have different effects on the power spectrum density and the maximal achievable data rate. The analysis of impact of parameters in the system on the power spectrum density will help the system designer select proper parameter set to fit in emission power regulation and the required data rate in practical UWB systems. Some examples of parameter selection are also given to illustrate the impact of different parameters in the system on the power spectrum density.