Method for timing a pulsed communication system

• US 8,130,680 B1
• Filed: 01/24/2008
• Issued: 03/06/2012
• Est. Priority Date: 01/24/2008
• Status: Active Grant

• Current Assignee: L3 Technologies, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: McIntire, William K., Thomson, Larry S., Robbins, David H.
• Primary Examiner(s): Harper, Kevin C
• Assistant Examiner(s): CHOUDHRY, SAMINA F
• Application Number:
  US12/019,455
• Time in Patent Office: 1,503 Days
• Field of Search: 370/212, 370/213, 370/215, 370/276, 370/287, 370/324, 370/350
• US Class Current: 370/277
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0235 Avoidance by time multiplex
• CPC Class Codes: G01S 7/28 Details of pulse systems
• CPC Class Codes: H04L 5/1469 using time-sharing

Abstract

A method for timing a full duplex pulsed wireless communication system between first and second transceivers is disclosed. At least one of the transceivers is mobile. A propagation time between the first and second transceivers is calculated. A pulse period of the first transceiver is set to be twice the propagation time divided by an integer. The second transceiver'"'"'s pulse period is set to be equal to the pulse period of the first transceiver to enable the first and second transceivers to transmit and receive pulses with a substantially reduced risk of a collision between pulses transmitted from the first and second transceivers.

Claims

1. A method for timing a full duplex pulsed wireless communication system between a first transceiver and a second transceiver, wherein at least one of the first and second transceivers are mobile, comprising:

calculating a propagation time between the first and second transceivers, wherein the first transceiver transmits first pulses separated by first blanking periods in which the first transmitter does not transmit and that are interleaved between each of the first pulses, and wherein the second transceiver transmits second pulses separated by second blanking periods in which the second transmitter does not transmit and that are interleaved between each of the second pulses;

setting a first pulse period of the first transceiver to be twice the propagation time divided by an integer, wherein the first pulse period is a time between a start of one of the first pulses and a start of a next one of the first pulses and the integer is a positive number greater than zero; and

transmitting a timing of the first pulse period from the first transceiver to the second transceiver to enable setting a second pulse period of the second transceiver to be substantially equal to the first pulse period of the first transceiver to enable the first and second transceivers to transmit and receive pulses with a reduced risk of a collision between a plurality of the first pulses transmitted from the first transceiver to the second transceiver and a plurality of the second pulses transmitted from the second transceiver to the first transceiver, wherein the second pulse period is a time between a start of one of the second pulses and a start of one of a next one of the second pulses.

2. A method as in claim 1, wherein calculating a propagation time further comprises determining a distance between the first and second transceivers.

3. A method as in claim 2, wherein calculating a propagation time between the first and second transceivers further comprises calculating the propagation time by transmitting a pseudo-random bit sequence between the first and second transceivers.

4. A method as in claim 3, wherein transmitting the pseudo-random bit sequence further comprises transmitting a pseudo-random bit sequence comprised of a plurality of range bits, with one range bit transmitted in substantially each transmit burst that is transmitted between the first and second transceivers.

5. A method as in claim 4, wherein transmitting the range bit further comprises transmitting the range bit from the first transceiver to be received at the second transceiver and re-transmitted by the second transceiver back to the first transceiver, wherein a duration between the transmission of the range bit by the first transceiver and the reception of the range bit by the first transceiver is used to calculate one of the distance and the propagation time.

6. A method as in claim 1, further comprising calculating the propagation time based on a knowledge of a location of each of the first and second transceivers.

7. A method as in claim 1, further comprising:

modulating first data onto a plurality of the first pulses, and

transmitting the first pulses modulated with the first data from the first transceiver to the second transceiver.

8. A method as in claim 7, further comprising selecting the integer to enable a pulse width of each of the first pulses to be less than or equal to a maximum allowable period based on physical constraints of the first and second transceivers.

9. A method as in claim 1, further comprising updating the first pulse period of the first transceiver as the propagation time between the first and second transceivers changes.

10. A method as in claim 9, further comprising changing the first pulse period and the second pulse period of the first and second transceivers at an epoch signal in a pseudo-random bit sequence transmitted between the first and second transceivers to enable the first and second pulse periods to be changed synchronously between the first and second transceivers with no interruption in communication.

11. A method as in claim 1, further comprising setting duty cycles of the first and second transceivers such that the duty cycle of the first transceiver and the duty cycle of the second transceiver add to be less than 100% of the first pulse period.

12. A method as in claim 1, further comprising receiving a pulsed communication from the first transceiver at the second transceiver and communicating a pulsed response communication transmitted from the second transceiver to the first transceiver, wherein the pulsed response communication is offset from a center of the second pulse period of the second transceiver.

13. A method as in claim 12, further comprising offsetting the pulsed response communication early to attempt to enable the first transceiver to receive the pulsed response communication with no collisions and offsetting the pulsed response communication late if no reply is received at the second transceiver from the first transceiver.

14. A method as in claim 1, further comprising separating transmitted pulses from received pulses at the first and second transceivers by a guard band period having a sufficient length to enable the transceivers to be switched between transmit and receive modes.

15. A method as in claim 1, further comprising:

determining a change in a distance between the first and second transceivers;

calculating a new propagation time between the first and second transceivers based on the change in the distance; and

adjusting the first pulse period of the first transceiver based on the new propagation time.

16. A method as in claim 7, further comprising:

modulating second data onto a plurality of the second pulses, and

transmitting the second pulses modulated with the second data from the second transceiver to the first transceiver.

17. The method of claim 1, wherein:

the first transceiver is a radar transceiver, and

the first pulses are radar pulses.

18. The method of claim 17, wherein:

the second transceiver is a radar transceiver, and

the second pulses are radar pulses.

19. The method of claim 1, wherein:

each of the first pulses are substantially a same duration,

each of the first blanking periods are substantially a same duration,

each of the second pulses are substantially a same duration, and

each of the second blanking periods are substantially a same duration.

20. The method of claim 19, wherein a sum of a duty cycle of the first pulse period and a duty cycle of the second pulse period is less than one-hundred percent.

21. The method of claim 19, wherein:

a duty cycle of the first pulse period is less than fifty percent, and

a duty cycle of the second pulse period is less than fifty percent.

22. The method of claim 19, wherein a duration of each of the first blanking periods is at least two times a duration of each of the first pulses.