The Personal Communication Systems with global coverage use Integrated Satellite-Terrestrial approach with Low Earth Orbit satellite constellations. The frequency reuse problems in such systems are discussed. The advantages of the implementation here the proposed by the author Space Correlated – Code Division Multiple Access are considered too. The principles of generation and synchronization of used Unique Pseudo Noise codes are shown. The system architecture of a IST PCN, based on the proposed by the author Spatial Correlation Processing – Random Phase Spread Coding technology for LEO,s terminal and feeder lines, is given too.