Method and apparatus for determining propagation delays for use in wide area networks
View Patent ↗A system and method for determining a signal propagation delay between a transmitter and a receiver, and for adjusting a transmission time based on the propagation delay. A central station inserts a marker into a transmitted signal at a time corresponding to a received timing signal. The MCT receives the signal from the central station and determines a time difference between receipt of the marker and the detection of the time interval event. A transmission by the MCT is adjusted by an amount of time proportional to the time difference.
1. A mobile communications terminal (MCT), comprising:
a transceiver that receives signals from a network management center (NMC), the signals including a pilot signal with a marker and a grant signal indicating a time at which the MCT is to transmit a message to the NMC;
a processing, unit that determines a signal propagation delay offset based on the marker; and
wherein the processing unit causes the transceiver to transmit a message to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
2. The MCT of claim 1 , wherein the marker is based on a timing signal common to the MCT and the NMC.
3. The MCT of claim 1 , wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
4. The MCT of claim 3 , wherein said GPS timing signal comprises a one pulse-per-second signal front a global positioning satellite timing signal.
5. The MCT of claim 3 , wherein the pilot signal is inserted into the first signal at a time relative to the time interval.
6. A method for mobile communication, comprising:
receiving signals from a network management center (NMC), the signals including a pilot signal with a marker and a grant signal indicating a time at which the a mobile communications terminal (MCT) is to transmit a message to the NMC;
determining, by a processor, a signal propagation delay offset based on the marker; and
transmitting a message to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
7. The method of claim 6 , wherein the marker is based on a timing signal common to the MCT and the NMC.
8. The method of claim 6 , wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
9. The method of claim 8 , wherein said GPS timing signal comprises a one pulse-per-second signal from a global positioning satellite timing signal.
10. The method of claim 8 , wherein the pilot signal is inserted into the first signal at a time relative to the time interval.
11. An apparatus for mobile communication, comprising:
means for receiving signals from a network management center (NMC), the signals including a pilot signal with a marker and a grant signal indicating a time at which the a mobile communications terminal (MCT) is to transmit a message to the NMC;
means for determining a signal propagation delay offset based on the marker; and
means for transmitting a message to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
12. The apparatus of claim 11 , wherein the marker is based on a timing signal common to the MCT and the NMC, or wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
13. A computer program product, comprising:
a non-transitory computer-readable medium comprising:
code for causing a computer to receive signals from a network management center (NMC), the signals including a pilot signal with a marker and a grant signal indicating a time at which the a mobile communications terminal (MCT) is to transmit a message to the NMC;
code for causing the computer to determine a signal propagation delay offset based on the marker; and
code for causing the computer to transmit a message to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
14. The computer program product of claim 13 , wherein the marker is based on a timing signal common to the MCT and the NMC, or wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
15. A network management center (NMC), comprising:
a processing unit configured to insert a marker into a pilot signal;
a transceiver configured to transmit signals to a mobile communications terminal (MCT), the signals including the pilot signal with the marker and a grant signal indicating a time at which the MCT is to transmit a message to the NMC; and
wherein the transceiver is further configured to receive a message from the MCT at a time adjusted for a propagation delay offset determined by the MCT based on the marker to ensure receipt by the NMC at the expected time.
16. The NMC of claim 15 , wherein the marker is based on a timing signal common to the MCT and the NMC.
17. The NMC of claim 15 , wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
18. The NMC of claim 17 , wherein said GPS timing signal comprises a one pulse-per-second signal from a global positioning satellite timing signal.
19. The NMC of claim 17 , wherein the pilot signal is inserted into the first signal at a time relative to the time interval.
20. A method for mobile communication, comprising:
inserting, by a processor, a marker into a pilot signal;
transmitting signals to a mobile communications terminal (MCT), the signals including the pilot signal with the marker and a grant signal indicating a time at which the MCT is to transmit a message to the NMC; and
receiving a message from the MCT at a time adjusted for a propagation delay offset determined by the MCT based on the marker to ensure receipt by the NMC at the expected time.
21. The method of claim 20 , wherein the marker is based on a timing signal common to the MCT and the NMC.
22. The method of claim 20 , wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
23. The method of claim 22 , wherein said GPS timing signal comprises a one pulse-per-second signal from a global positioning satellite timing signal.
24. The method of claim 22 , wherein the pilot signal is inserted into the first signal at a time relative to the time interval.
25. An apparatus for mobile communication, comprising:
means for inserting a marker into a pilot signal;
means for transmitting signals to a mobile communications terminal (MCT), the signals including the pilot signal with the marker and a grant signal indicating a time at which the MCT is to transmit a message to the NMC; and
means for receiving a message from the MCT at a time adjusted for a propagation delay offset determined by the MCT based on the marker to ensure receipt by the NMC at the expected time.
26. The apparatus of claim 25 , wherein the marker is based on a timing signal common to the MCT and the NMC, or wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.
27. A computer program product, comprising:
a non-transitory computer-readable medium comprising:
code for causing a computer to insert a marker into a pilot signal;
code for causing the computer to transmit signals to a mobile communications terminal (MCT), the signals including the pilot signal with the marker and a grant signal indicating a time at which the MCT is to transmit a message to the NMC; and
code for causing the computer to receive a message from the MCT at a time adjusted for a propagation delay offset determined by the MCT based on the marker to ensure receipt by the NMC at the expected time.
28. The computer program product of claim 27 , wherein the marker is based on a timing signal common to the MCT and the NMC, or wherein the marker comprises a pilot signal inverted at a time corresponding to a local GPS timing signal.