The LEO satellite systems will play an important role in the future personal communications networks because of their several advantages over GEO and MEO satellite systems. The extensive frequency reuse in a LEO Satellite System, in order to enhance the capacity, produces cochannel interference no matter what kind of multiple access scheme it is based on. On previous work, the carrier-to-interference ratio has been analyzed on a satellite placed only at the equator and only for the uplink case at co-rotation orbits. Therefore, it is important to evaluate the analysis for an upper latitude because the population is more concentrated around +40° of latitude. The downlink case is also relevant to analyze in order to know the level of the desired signal over the interference, as well as the counter-rotating orbits. The present thesis analyzes and evaluates different scenarios for FDMA and CDMA at two different latitudes at co and counter rotating orbits. It also shows the variation of the carrier-to-interference ratio and the outage probability over different frequency reuse schemes for uplink and downlink. Also an exponential model is proposed and included for the spot-beam antenna gain.