Return link channel capacity of wideband CDMA-based LEO satellite system with multiple-beam and diversity

In this paper, the performance of a wideband CDMA single-user return link with the diversity reception is investigated by simulation under a realistic LEO (low earth orbit) mobile satellite channel model. Since there are fundamental differences in the channel characteristics between the LEO mobile satellite and terrestrial mobile systems, such as relatively small delay spread and the varying elevation angles, these factors are taken into account for the channel model. Based on this simulation result, we evaluate the total channel capacity for the multi-beam system with the various system parameters, such as the power efficiency of satellite transponder, encoding scheme and EIRP or G/T of antenna, taken into account. It is shown that the different types of diversity techniques can be successfully applied to combat the performance degradation due to the low elevation angle and thus, warrant the high-quality and low-cost implementation.