Matched filter for scalable spread spectrum communications systems
A spread spectrum communications system using long, scalable PN sequences to achieve variable communication rates using a low-complexity and scalable matched filter architecture to provide a large processing gain, robust recovery of multiple devices in long reach, high ambient-noise environments.
1. A transmitter for a spread spectrum communications system, comprising:
a data source;
a first multiplier/mixer spreading data from said data source with a first pseudo noise source;
a second multiplier/mixer spreading data from said first mixer with a second pseudo noise source, wherein the first pseudo noise source and the second pseudo noise source are not used to lock a receiver to the transmitter; and
an RF transmitter.
2. A spread spectrum communications system, as recited in claim 1 , wherein said first pseudo noise source provides a variable length code sequence.
3. A spread spectrum communications system, as recited in claim 1 , wherein said first pseudo noise source provides a fixed length code sequence.
4. A spread spectrum communications system, as recited in claim 1 , wherein said second pseudo noise source provides a fixed length code sequence.
5. A spread spectrum communications system, as recited in claim 1 , wherein said second pseudo noise source provides a variable length code sequence.
6. A spread spectrum communications system, as recited in claim 1 , wherein said first multiplier mixer spreads said data from said data source with a variable length PN code.
7. A spread spectrum communications system, as recited in claim 1 , wherein said first multiplier mixer spreads said data from said data source with a fixed length PN code.
8. A spread spectrum communications system, as recited in claim 1 , wherein said second multiplier mixer spreads said data from said first mixer with a fixed length PN code.
9. A spread spectrum communications system, as recited in claim 1 , wherein said second multiplier mixer spreads said data from said first mixer with a variable length PN code.