Resumen
Peaceful coexistence is a major implementation issuefor both cognitive radios and ultra wideband (UWB) systems.Accordingly, the UWB impulse radio (UWB-IR) based WirelessPersonal Area Network (WPAN) standard IEEE 802.15.4a hassuggested using linear combination of pulse to limit interfer-ence to coexisting primary systems. In this paper, motivatedby implementing the IEEE 802.15.4a based UWB-IR systemsfor peaceful coexistence, we consider the implementation oflinear combination of pulses as suggested by the standard.Accordingly, we (i) design possible linearly combined pulses thatconform to the standard requirements, (ii) consider coherentand noncoherent receiver structures that can be adapted for thephysical layer of the IEEE 802.15.4a standard, (iii) investigatethe effect of channel models on the system performance, and(iv) study the UWB-IR system performance in the presenceof narrowband and orthogonal frequency division multiplexing(OFDM) based wideband primary systems with various band-widths and subcarriers. The study shows that the UWB-IR systemperformance can be significantly improved by selecting suitablepulses for transmission and employing appropriate filteringtechniques at the receiver when the primary system is active.For the implementation of IEEE 802.15.4a based UWB systemscomplying with coexistence requirements, the results of this studyshould be carefully considered.