Analysis of Jammer Resistant, Spread spectrum, VSAT Communication Scheme for Maritime Platform Using DSCDMA

In this thesis, a new VSAT (Very Small Aperture Terminal) communication system is developed using Direct Sequence Code Division Multiple Access (DS-CDMA) for multiple maritime mobile users in the footprint of national communication satellites. The Forward Error Correction (FEC) is implemented by applying convolution encoding with soft decision decoding. The worst-case scenario is always considered by placing VSAT system and different types of jammers on the footprint where the minimum signal-to-noise ratio is possible. Using this assumption, the performance of the system is analyzed for different convolution code rates, for a different number of users and for the different jammer powers. The Walsh codes are used to establish an orthogonal cover between CDMA channels in a VSAT. Additionally, spread spectrum is included by PN sequences to ensure as much orthogonal coverage as possible between the VSATs. Also, that spreading is the key to minimizing these hostile jammer effects. After analyzing VSAT system for possible scenario elements, optimum system parameters are introduced for military and civilian applications.