On the impact of ultra wide band (UWB) system on macrocell downlink of IS-136 systems

In this paper, the effect of the UWB interference on the IS-136 downlink is studied for different UWB power density. The UWB interference power is calculated using the free space propagation model. It is found that, for relatively high UWB power density (-60 dBm/MHz), the effect of the UWB signals is very high when the distance between the UWB transmitter and the IS-136 receiver is 1 m. It is found that the spectrum mask proposed by the FCC for indoor application (-53 dBm/MHz in the IS-136 upper band and -41 dBm/MHz in the IS-136 lower band) is very high to be tolerated by the IS-136 mobile systems and we have to propose another spectrum mask with lower UWB power density. Our recommended power densities are: -84 dB/NMz for the IS-136 working at its upper band and -91 dB/MHz for the IS-136 working at its lower band.