09-04-2011, 10:51 AM
PRESENTED BY:
S ADITYA THIMMA REDDY
PUSHPAVALLI R
P VENKATA KRISHNA TEJA
S PENNA OBULAMMA
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Abstract
Spread-spectrum telecommunications is a signal structuring technique that employs direct sequence, frequency hopping, or a hybrid of these, which can be used for multiple access and/or multiple functions. This technique decreases the potential interference to other receivers while achieving privacy. Frequency-hopping spread spectrum (FHSS), direct-sequence spread spectrum (DSSS), time-hopping spread spectrum (THSS), chirp spread spectrum (CSS), and combinations of these techniques are forms of spread spectrum Each of these techniques employs pseudorandom number sequences or PN sequences created using pseudorandom number generators to determine and control the spreading pattern of the signal across the allotted bandwidth. The generation of PN sequences for spread spectrum applications is a topic that has received considerable attention in the technical literature. Our project aims at generation of PN sequences namely m-sequence, gold sequence, kasami sequence, orthogonal sequence, generalized orthogonal sequence and verification of their cross correlation and auto correlation properties for spread spectrum applications. The cross correlation of any two PN sequences should be zero in order to provide complete interference and the auto correlation function ᶲ(j) of any PN sequence should be maximum at j=0 and zero for all other values. These sequences are generated in mat lab and their properties are verified.