Systems and methods for beaconing in wireless networks with low probability of detection
First Claim
Patent Images
1. In a wireless network including a plurality of nodes, a method of performing neighbor discovery, the method comprising:
- generating a signal at a first node for alerting other nodes in the network of the presence of the first node, the signal comprising a spread signal;
broadcasting the signal from the first node, the broadcasted signal having a low probability of detection by an unintended receiver,receiving the signal at a second node;
filtering the received signal at the second node using a filter matched to a spreading sequence or code used to spread the signal;
calculating an energy associated with the filtered signal;
establishing a threshold;
determining whether the energy is greater than the threshold;
identifying, by the second node, the first node as a neighbor node when the energy is greater than the threshold;
transmitting a message from the second node to the first node, the message comprising information identifying the second node;
repeating the broadcasting of the signal from the first node;
adjusting a power level associated with broadcasting the signal based on whether the message from the second node has been received by the first node; and
changing, by the first node, the spreading sequence or code used to spread the signal after a number of broadcasts.
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Abstract
Systems and methods for performing neighbor discovery in a network (100) including a number of nodes are provided. A first node (110) in the network (100) generates a spread signal for alerting other nodes in the network (100) of the presence of the first node (110). The first node (110) broadcasts the signal and a second node (120) receives the signal and calculates an energy associated with the received signal. The second node (120) also determines whether the energy is greater than a threshold and identifies the first node (110) as a neighbor node when the energy is greater than the threshold.
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Citations
18 Claims
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1. In a wireless network including a plurality of nodes, a method of performing neighbor discovery, the method comprising:
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generating a signal at a first node for alerting other nodes in the network of the presence of the first node, the signal comprising a spread signal; broadcasting the signal from the first node, the broadcasted signal having a low probability of detection by an unintended receiver, receiving the signal at a second node; filtering the received signal at the second node using a filter matched to a spreading sequence or code used to spread the signal; calculating an energy associated with the filtered signal; establishing a threshold; determining whether the energy is greater than the threshold; identifying, by the second node, the first node as a neighbor node when the energy is greater than the threshold; transmitting a message from the second node to the first node, the message comprising information identifying the second node; repeating the broadcasting of the signal from the first node; adjusting a power level associated with broadcasting the signal based on whether the message from the second node has been received by the first node; and changing, by the first node, the spreading sequence or code used to spread the signal after a number of broadcasts. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 12, 13, 14, 17)
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7. In a network comprising a plurality of nodes, a first node comprising:
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an omni-directional antenna; a directional antenna; a processor configured to generate a spreading sequence that identifies the first node; a first transmitter configured to broadcast the spreading sequence using the omni-directional antenna; a receiver configured to receive a message from a second node, the message identifying the second node and indicating that the second node is a neighbor node; and a second transmitter configured to transmit data to the second node using the directional antenna after the message from the second node is received, the first transmitter being further configured to; repeat the broadcast of the spreading sequence, and adjust a power level associated with broadcasting the spreading sequence based on whether the message from the second node has been received, and the processor being further configured to; change the spreading sequence after a number of broadcasts.
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11. A computer-readable medium having stored thereon a plurality of computer executable instructions, said instructions including sequences of instructions which, when executed by a computer, cause said computer to:
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retrieve a spreading sequence that identifies a first node in a wireless network; broadcast the spreading sequence using an omni-directional antenna, the spreading sequence having a low probability of detection by an unintended receiver; receive a message from a second node in the wireless network, the message identifying the second node and indicating that the second node is a neighbor node; transmit data packets to the second node using a directional antenna after the message from the second node is received; repeat the broadcast of the spreading sequence a number of times; adjust a power level associated with broadcasting the spreading sequence based on whether the message from the second node has been received; and change the spreading sequence after a number of broadcasts.
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15. A system for performing neighbor discovery in a wireless network, comprising:
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means for generating a signal at a first node for alerting other nodes in the network of the presence of the first node, the signal comprising a spread signal; means for broadcasting the signal from the first node using an omni-directional antenna or a set of sectored antennas; means for receiving the signal at a second node; means for filtering the received signal at the second node using a filter matched to a spreading sequence or code used to spread the signal; means for calculating an energy associated with the filtered signal; means for determining whether the energy is greater than a threshold; means for identifying, by the second node, the first node as a neighbor node when the energy is greater than the threshold; means for transmitting a message from the second node to the first node using a directional antenna, the message comprising information identifying the second node; means for repeating the broadcasting of the signal from the first node a number of times; means for adjusting a power level associated with broadcasting the signal based on whether the message from the second node has been received; and means for changing a spreading sequence used to spread the signal after a number of broadcasts.
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16. In a network including a plurality of nodes, a method of performing neighbor discovery, the method comprising:
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broadcasting a spreading sequence from at least a first node in the network using an omni-directional antenna, the spreading sequence having a low probability of detection by an unintended receiver and being used to alert other nodes in the network of the presence of the first node; detecting, by at least a second node in the network, the first node using a filter matched to detect the spreading sequence used by the first node; identifying, by the second node, the first node as a neighbor; selecting, by the second node, a directional antenna; transmitting a message from the second node to the first node using the directional antenna, the message comprising information identifying the second node; broadcasting the spreading sequence a number of times; adjusting the power level associated with the broadcasting based on whether a reply message, indicating that at least the second node has detected the spreading sequence, has been received by the first node; and changing the spreading sequence after a number of broadcasts.
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18. A first node in a wireless network comprising:
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an omni-directional antenna; a directional antenna; a transmitter configured to transmit a signal for alerting other nodes in the network of the presence of the first node via the omni-directional antenna, the signal comprising a spread signal that is spread using at least one of a direct sequence, a frequency hopping sequence or a number of short pulses; and a receiver configured to receive a message from a second node in the network, the message identifying the second node as a neighbor node and being sent in response to the second node detecting the signal from the first node, and wherein the transmitter is further configured to; repeat the transmission of the signal, adjust a power level at which the signal is transmitted based on whether the message from the second node has been received, and transmit data packets to the second node using the directional antenna after a neighbor relationship with the second node has been established, the first node further comprising; a processor configured to change a spreading sequence or code used to spread the signal after a number of transmissions.
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Specification