Coexistence of DS CDMA PCN and analog FM: performance degradation of the SSSC-FM channels due to spread spectrum overlay

摘要

The spectrum overlay of a CDMA PCN on a preexisting narrowband, analog, corrupted by AWGN FM channel is considered. This overlay can increase communications capacity, within a geographical area, and spectral efficiency. The overlayed PCN is assumed to employ DS spreading, using maximal length pseudorandom sequences. The interference the FM channel experiences is estimated, and an extremely severe test is simulated using a PCN overlayed on a preexisting 600-channel SSSC-FM FDM microwave line-of-sight radio link. It is found that the interference caused by the PCN depends on the carrier frequency separation between the two systems, the power of the EM system, the length of the SS system pseudorandom sequences, and the data rate and power of the PCN users.