Performance in QPSK and BPSK synchronous sequence DS-CDMA satellite systems
M. Reyes Ayala, E.A. Andrade Gonzalez, J. de Jesih Roa Franco · 2005
CDMA is one of the most important multiple access schemes. In this paper, we analyze a synchronous DS-CDMA, where the error probability and the maximum number of users, are used to evaluate its performance. The synchronous DS-CDMA is compared with asynchronous DS-CI)MA, to emphasize their advantages or disadvantages. The digital link budget is also employed to compare altitude orbits and features of terminal architectures. shift-register, due that this will produces the same combination. The output of the filter gives a very large and almost unpredictable binary pseudorandom sequence. This feature produces an encFypt system, because it is necessary to know the pseudorandom sequence to retrieve the original information. The shift-register pseudorandom sequence generator and N- step digital filter, look the same, but the output of the filter must be a bipolar line code to eliminate the D. C. component. The maximum period of the pseudorandom sequences L is determined by (1).