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Direct-Sequence Spread Spectrum with Cyclic Code Shift Keying. Prashant Singh Rice University Advisor: Michael B. Pursley Clemson University. Outline. Cyclic Code Shift Keying (CCSK) CCSK Receivers Methods Results Conclusion. Non-orthogonality of CCSK.
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Direct-Sequence Spread Spectrum with Cyclic Code Shift Keying Prashant Singh Rice University Advisor: Michael B. Pursley Clemson University
Outline • Cyclic Code Shift Keying (CCSK) • CCSK Receivers • Methods • Results • Conclusion
Non-orthogonality of CCSK S0: 01111100111010010000101011101100 S7: 01110100100001010111011000111110 # of matches: 18 # of differences: 14 Inner product: 4
Signal Generation S0: 0111110011…1011101100 S1: 111110011…10111011000 S6: 0011…1011101100011111
Masking Data Sequence … 0100 Output … 0011 XOR … 0111 Signature Sequence
Receiver • Signature sequence mask removal • 32 matched filters • Largest output wins
Alternate Receiver • Used by military system • Signature sequence mask removal • 3 matched filters • Takes advantage of signal set • CCSK specific
Simulation • Simulates “standard” receiver • Assumes time-synchronization • Uses m-sequence for signature
1 1 1 1 1 1 1 1 1 1 Signature Sequence 10 cells Linear Feedback Shift Register
Verification • Orthogonal signal set • Pair-wise error probability
Future Work • Rake receiver • Sampling error effects on alternate receiver • Non-coherent receiver