Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2008-01-29
2008-01-29
Phu, Phuong (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S140000, C375S141000, C370S320000, C370S335000
Reexamination Certificate
active
07324580
ABSTRACT:
A method and apparatus are disclosed for modulating a communication signal in a CDMA environment using orthogonal N by N Hadamard spread spectrum codes. Orthogonal spreading codes are used that have lengths that are not a power-of 2 to provide additional channel variability for various multimedia applications and increase the flexibility of the number of channels/bandwidth relationship. The Hadamard codes are multiples of 4 (4n) and demonstrate a good cross-correlation property, making them very useful in the flexible design of CDMA systems. A transmitter encodes each of N data streams (N not being a power of 2), to be transmitted using a 4n codeword, Ni. The received signal is passed through a filter matched to the characteristics of the appropriate codeword, Ni, and PN spreading sequence.
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Lucent Technologies - Inc.
Phu Phuong
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