Ad-hoc network acquisition using chaotic sequence spread waveform
View Patent ↗Method and system for identifying neighbor nodes in an ad-hoc wireless network including two or more nodes. The method involves generating a beacon signal at a first node of the network for alerting other nodes in the network of the presence of the first node. A digitally generated first spreading sequence is also generated at the first node. Thereafter, the beacon signal is modulated with the first spreading sequence to produce a spread spectrum signal which is then transmitted. The spreading sequence is selected to be a chaotic sequence.
1. A method for identifying neighbor nodes in an ad-hoc wireless network including a plurality of nodes, comprising:
generating a beacon signal at a first node of said network for alerting other nodes in said network of the presence of said first node, said beacon signal comprising beacon data and having a data rate, said beacon data including information specifying at least one of a data initialization parameter and a network characteristic that is useful for establishing a communication link between said first node and said other nodes of said network;
digitally generating a first chaotic spreading sequence at said first node;
modulating said beacon signal with said first chaotic spreading sequence to produce a spread spectrum beacon signal; and
transmitting said spread spectrum beacon signal at a first power level without risk of detection, wherein said first power level exceeds a second power level at which a beacon signal could be transmitted without risk of detection using a non-chaotic spreading code.
2. The method according to claim 1 , further comprising transmitting said spread spectrum beacon signal from said first node in an omni-directional pattern.
3. The method according to claim 1 , further comprising receiving said spread spectrum beacon signal with at least a second node in said network and coherently demodulating said spread spectrum beacon signal using a second chaotic spreading sequence digitally generated at said second node to obtain said beacon signal.
4. The method according to claim 3 , further comprising:
identifying with said second node said first node as a neighbor node based on said beacon signal; and
transmitting a message from said second node to said first node in response to said beacon signal.
5. The method according to claim 4 , further comprising transmitting said message from said second node to said first node using a directional antenna.
6. The method according to claim 4 , further comprising transmitting network data between said first and said second node exclusive of using said first or second chaotic spreading sequence for modulating said network data following transmission of said beacon and said message.
7. The method according to claim 1 , wherein said beacon signal is modulated to include beacon data, exclusive of said first chaotic spreading sequence, identifying one or more communication protocols associated with said ad-hoc network.
8. The method according to claim 7 , wherein said beacon data includes one or more items selected from the comprising a data transmission rate, a transmission frequency, a receive frequency, a transmission time, a transmission protocol, a quality of service parameter, a bit error rate parameter, an available bandwidth, a position of a node, a node velocity, and a node acceleration.
9. The method according to claim 1 , wherein said first node is selected to have a location near a periphery of said network.
10. The method according to claim 1 , wherein said step of generating said digitally generated first chaotic spreading sequence further comprises:
selecting a plurality of polynomial equations;
using residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for said plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values.
11. The method according to claim 10 , wherein said step of generating said digitally generated first chaotic spreading sequence further comprises determining a series of digits in a weighted number system based on said plurality of RNS residue values.
12. An ad-hoc network including a plurality of nodes, comprising:
a first node including
a processor configured to generate a beacon signal for alerting other nodes in said network of the presence of said first node, said beacon signal comprising beacon data and having a data rate, said beacon data including information specifying at least one of a data initialization parameter and a network characteristic that is useful for establishing a communication link between said first node and said other nodes of said network;
a first spreading sequence generator configured to digitally generate a first chaotic spreading sequence;
a first modulator configured to modulate said beacon signal with said first chaotic spreading sequence to produce a spread spectrum beacon signal; and
a first transmitter configured to transmit said spread spectrum beacon signal at a first power level without risk of detection, wherein said first power level exceeds a second power level at which a beacon signal could be transmitted without risk of detection using a non-chaotic spreading code.
13. The ad-hoc network according to claim 12 , wherein said first node further comprises a omni-directional antenna and said spread spectrum beacon signal is broadcast from said omni-directional antenna.
14. The ad-hoc network according to claim 12 , further comprising at least a second node including:
a receiver configured to receive said spread spectrum beacon signal;
a second spreading sequence generator configured to digitally generate a second chaotic spreading sequence; and
a demodulator configured to demodulate said spread spectrum beacon signal using said second chaotic spreading sequence to obtain said beacon signal.
15. The ad-hoc network according to claim 14 , wherein said second node further comprises:
a second processor configured to identify said first node as a neighbor node based on said beacon signal and generating a message in response to said beacon signal; and
a second transmitter responsive to said second processor and configured to transmit said message to said first node.
16. The ad-hoc network according to claim 15 , wherein said second node further comprises a directional antenna coupled to said second transmitter for transmitting said message from said second node to said first node.
17. The ad-hoc network according to claim 15 , wherein following said transmission of said beacon signal and said message, said first and second transmitter are configured to transmit network data between said first and said second node exclusive of using said first or second chaotic spreading sequence.
18. The ad-hoc network according to claim 12 , wherein said first node further comprises a beacon signal modulator configured to modulate said beacon signal to include data, exclusive of said first chaotic spreading sequence, and identifying one or more communication protocols associated with said ad-hoc network.
19. The ad-hoc network according to claim 18 , wherein said beacon data includes one or more items selected from the comprising a data transmission rate, a transmission frequency, a receive frequency, a transmission time, a transmission protocol, a quality of service parameter, a bit error rate parameter, an available bandwidth, a position of a node, a node velocity, and a node acceleration.
20. The ad-hoc network according to claim 12 , wherein said first node is located at or adjacent to a periphery of said network.
21. The ad-hoc network according to claim 12 , wherein said first spreading sequence generator comprises a computing means configured to use residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for a plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values.
22. The ad-hoc network according to claim 21 , wherein said first spreading sequence generator further comprises a mapping means configured to determine a series of digits in a weighted number system based on said plurality of RNS residue values.
23. A network node for communicating in ad-hoc network including a plurality of nodes, comprising:
a processor configured to generate a beacon signal for alerting other nodes in said network of the presence of said network node, said beacon signal comprising beacon data and having a data rate, said beacon data including information specifying at least one of a data initialization parameter and a network characteristic that is useful for establishing a communication link between said first node and said other nodes of said network;
a first spreading sequence generator configured to digitally generate a first chaotic spreading sequence;
a first modulator configured to modulate said beacon signal with said first chaotic spreading sequence to produce a spread spectrum beacon signal; and
a first transmitter configured to transmit said spread spectrum beacon signal at a first power level without risk of detection, wherein said first power level exceeds a second power level at which a beacon signal could be transmitted without risk of detection using a non-chaotic spreading code.
24. The network node according to claim 23 , wherein said first node further comprises a beacon signal modulator configured to modulate said beacon signal to include data, exclusive of said first chaotic spreading sequence, and identifying one or more communication protocols associated with said ad-hoc network.
25. The network node according to claim 24 , wherein said beacon data includes one or more items selected from the comprising a data transmission rate, a transmission frequency, a receive frequency, a transmission time, a transmission protocol, a quality of service parameter, a bit error rate parameter, an available bandwidth, a position of a node, a node velocity, and a node acceleration.
26. The ad-hoc network according to claim 23 , wherein said spreading sequence generator comprises a computing means configured to use residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for a plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values.
27. The ad-hoc network according to claim 26 , wherein said spreading sequence generator further comprises a mapping means configured to determine a series of digits in a weighted number system based on said plurality of RNS residue values.