Method of forming directional wireless networks using in-band channels

• US 20070087758A1
• Filed: 10/14/2005
• Published: 04/19/2007
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Norris, Paul, Pei, Guangyu, Kim, Jae, Nast, Douglas
• Granted Patent: US 7,420,944 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention is directed to a method of forming a mobile network using Phased Array Antennas. Mobile nodes search for nodes with which to form a network by either transmitting low level announcement signals on a wide spoiled beam directional antenna at progressively increasing power levels, or by receiving announcement signals using a high-gain, narrow directional beam. Low power announcements are compensated for by processing gain in the receive modem. Nodes randomly decide at each step of the scan whether to transmit or receive. Two control slots in an epoch are used for neighbor discovery. The first control slot is to announce or receive an announcement, and the second control slot is used to acknowledge the receipt of an announcement packet. The neighbor discovery process uses in-band communications. The directional communications permit simultaneous links in close proximity to other links without interference.

Claims

1. A method of mutually discovering relative locations of a plurality of mobile nodes to form a data communications network, the method comprising:

initializing a signal transmission power level at a minimum power level;

initializing an antenna scan direction in a first predetermined direction of a plurality of directions;

randomly selecting, for each mobile node of the plurality of mobile nodes, to transmit or to receive an announcement packet during one scan direction;

transmitting, by at least one node, an announcement packet via an antenna beam in response to randomly selecting to transmit an announcement packet, the antenna beam being directed in the predetermined direction in a first synchronized time interval;

focusing, by at least one node, an antenna receiving beam to receive an announcement packet transmitted from a transmitting node in response to randomly selecting to receive an announcement packet in the first synchronized time interval;

resetting the first predetermined direction of the plurality of directions and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node; and

repeating the steps of resetting the direction for each scan, and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node until all of the plurality of directions have been scanned.

2. The method as set forth claim 1, also including:

incrementing the power level by a predetermined power level increment in response to a reservation signal not being received by a transmitting node in all scan directions at the initial power level, and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node, resetting the direction for all of the plurality of scan directions;

for progressive power level increments until the signal transmission power level exceeds a predetermined maximum power level.

3. The method as set forth in claim 2, also including:

transmitting a reservation signal from the receiving node back to the transmitting node in a second synchronized time interval, in response to a receiving node detecting an announcement packet from the transmitting node;

negotiating a data link between the transmitting node and the receiving node in response to the transmitting node receiving the reservation signal from the receiving node;

aligning the antenna from the transmitting node with the antenna from the receiving node in response to negotiating a data link; and

configuring the transmitting node to transmit a narrow, directional high power beam for communication with the receiving node.

4. The method as set forth in claim 2, also including returning the transmission power level to the minimum power level and the antenna direction to the first predetermined direction and repeating the steps of randomly selecting to transmit or to receive an announcement packet during one scan direction;

transmitting an announcement packet in a first synchronized time interval; and

focusing by at least one node a receiving beam to receive an announcement packet transmitted from a transmitting node, until a data link is activated for the transmitting node.

5. The method of claim 1, wherein transmitting of the announcement packet is via a wide angle communication beam.

6. The method of claim 5, wherein the antenna receiving beam is a narrow angle communication beam for reception of an announcement packet.

7. A method of forming an ad hoc mobile network using a spatial time division multiple access protocol, comprising:

synchronizing a plurality of mobile nodes to predefined epochs of time for communication scheduling;

dividing the epochs of time into a plurality of equal time slots;

designating at least two of the equal time slots as control signaling slots;

simultaneously transmitting or receiving an announcement packet in a first control signaling time slot by the plurality of mobile nodes;

transmitting a reservation signal by at least one mobile node in a second control signaling time slot in response to receiving a transmitted signal from at least one mobile node in the first control signaling time slot; and

establishing a data link between the transmitting node and the receiving node in response to the transmitting node receiving a reservation signal and

communicating between the transmitting and the receiving mobile nodes via directional antenna high gain high rate data link using at least two additional time slots of the plurality of equal time slots.

8. A method of forming a mobile ad hoc network of a plurality of mobile nodes using directional antennas comprising:

randomly assigning each node of a plurality of nodes randomly between a transmitting node and a receiving node;

directionally scanning over a predetermined range associated with a first power level with a first beam carrying an announcement signal, for a transmitting node;

simultaneously with the scanning of the first beam, directionally scanning at a highest power level with a second beam, for a receiving node;

increasing the level of the first power level to extend the predetermined range being scanned by the transmitting node, for a plurality of successive power level increments, up to a maximum power level;

transmitting a reserve signal from the receiving node to the transmitting node the announcement signal; and

establishing a data link between the receiving node and the transmitting node for high speed high gain operational communications in response to the receiving node receiving a transmitted signal from the transmitting node.

9. The method as set forth in claim 8, also including resetting the transmitting power level to the first power level and repeating the scanning steps for the first power level and for the successive power levels.

10. The method of claim 8, wherein the announcement signals and the reserve signals are transmitted according to the spatial time division multiple access protocol comprising:

synchronizing a plurality of potentially mobile nodes to predefined epochs of time for communication scheduling;

dividing the epochs of time into a plurality of equal time slots;

assigning at least two of the equal time slots as control signaling slots;

simultaneously transmitting or receiving an announcement packet in a first control signaling time slot;

transmitting a reservation signal in response to a received signal in a second control signaling time slot;

establishing a data link in response to receiving a reservation signal; and

communicating between at least two mobile nodes via directional antenna high gain high rate data link using at least two of the plurality of equal time slots not assigned to control signaling.

11. The method as set forth in claim 8, wherein the first beam is configured as a wide angle spread beam.

12. The method as set forth in claim 8, wherein the second beam is configured as a narrow spread beam.

13. The method as set forth in claim 8, wherein the directional antenna is a phased array antenna.

14. The method as set forth in claim 13, wherein the phased array antenna is electronically guided to change directions within a time interval less than a predetermined epoch of time.

15. A mobile ad hoc communications network system comprising:

a plurality of mobile nodes;

a communications protocol for communications between mobile nodes;

each mobile node comprising at least one directional antenna, the at least one directional antenna having a plurality of power levels for scanning; and

a control device for transmitting and receiving data packets, the control device being configured for adjusting a power level of the at least one directional antenna at a plurality of successively increasing power levels and directing the at least one directional antenna in a plurality of directions.

16. The system of claim 15, wherein the control device is also configured for resetting the first predetermined direction of the plurality of directions and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node;

repeating the steps of resetting the direction for each scan, and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node, until all of the plurality of directions have been scanned.

17. The system of claim 16, wherein the control device is also configured for transmitting a reservation signal from the receiving node back to the transmitting node in a second synchronized time interval in response to a receiving node detecting a received announcement packet from the detected transmitting node;

negotiating a data link between the transmitting node and the receiving node in response to the transmitting node receiving a reservation signal from the receiving node;

aligning the transmitting node antenna with the receiving node antenna; and

configuring the transmitting node signal carrier beam to a narrow, directional high power beam.

18. The system of claim 17, wherein the control device is also configured for incrementing the power level by a predetermined power level increment in response to a reservation signal not being received by a transmitting node in all scan directions at the initial power level, and repeating the steps of transmitting an announcement packet and focusing a receiving beam in response to an announcement signal not being received by a receiving node, resetting the direction for all of the plurality of scan directions, the power level being incremented in progressively greater power level increments until the signal transmission power level exceeds a predetermined maximum power level.

19. The system of claim 15, wherein the control device is also configured for randomly selecting, for each mobile node of the plurality of mobile nodes, to transmit or to receive an announcement signal during one antenna scan direction and transmits an announcement signal in response to randomly selecting to transmit an announcement packet;

and focusing a receiving beam to receive an announcement signal transmitted from a transmitting node in response to randomly selecting to receive an announcement packet.

20. The system of claim 15, wherein the directional antenna is a phased array antenna is steerable in a plurality of directions.

21. The system of claim 20, wherein the phased array antenna is capable of changing directions within less than an epoch of 100 msec in duration.