Ultra wideband impulse radio spectrum control independent of time hopping codes

This paper addresses the problem of power spectral density control independent of time hopping codes for impulse radio with pulse amplitude modulation in designated narrow frequency band whose bandwidth is much smaller than the impulse radio bandwidth. The influences on the power spectral density attributed to the ultra wideband pulse and the spread spectrum parameters are analyzed, based on which the ways are presented to remove the discrete spectral lines and suppress the power spectral density independently of time hopping codes in terms of choosing optimal spread spectrum parameters and ultra wideband pulse in designated frequency band whose bandwidth is much smaller than the pulse repetition frequency of impulse radio. All of the theoretical analysis are demonstrated by simulations.