Improved PCN efficiency through the use of spectral overlay

The 1850-1990 MHz band is being considered for shared use with the fixed service microwave users. To use this band most effectively it should also be shared by several competitive broadband code division multiple access (CDMA) personal communication network (PCN) systems. It is demonstrated how two or more competitive systems can share the spectrum without interfering with each other, without significantly decreasing the chip rate (and hence the bandwidth) of each PCN system, and without increasing the level of interference seen by the fixed service microwave user. This is extremely important since the wider the bandwidth the more immune is the PCN system to fading due to multipath propagation. It is shown that by staggering the frequencies, a significant increase in the number of services results with only a small decrease in performance