Method and apparatus for determining propagation delays for use in wide area networks
AssigneeQUALCOMM Incorporated
InventorsJudd Erlenbach, Franklin J. Gutterman, Bin Tian
Life of this patent
Estimating the term…
Abstract
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.
Claims12
An apparatus for determining a propagation delay between a mobile communications terminal (MCT) and a network management center (NMC), comprising:
- means for receiving a response from said NMC to a request by said MCT to transmit a message to said NMC at an expected time;
- means for receiving a first signal from said NMC;
- means for detecting an inverted pilot signal, which is inverted relative to a GPS timing signal, sent from said NMC, over a time interval during which said GPS timing signal is commonly received by said MCT and said NMC;
- means for determining a signal propagation delay offset from a time difference between receipt of the commonly received GPS timing signal and receipt of the inverted pilot signal;
- and
- means for transmitting said message from said MCT to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
A non-transitory computer-readable medium comprising program instructions which are computer-executable to implement a method
- for determining a propagation delay between a mobile communications terminal (MCT) and a network management center (NMC), the method comprising:
- receiving a response from said NMC to a request by said MCT to transmit a message to said NMC at an expected time;
- receiving a first signal from said NMC;
- detecting an inverted pilot signal which is inverted relative to a GPS timing signal, sent from said NMC, over a time interval during which said GPS timing signal is commonly received by said MCT and said NMC;
- determining a signal propagation delay offset from a time difference between receipt of the commonly received GPS timing signal and receipt of the inverted pilot signal;
- and
- transmitting said message from said MCT to said NMC at a time adjusted for said propagation delay offset to ensure receipt by said NMC at said expected time.
A mobile communications terminal (MCT) comprising:
- a GPS receiver that receives a GPS timing signal;
- a transceiver that receives signals from a network management center (NMC), the signals including a message indicating a time at which the MCT is to transmit a message to the NMC;
- a processing unit that detects an pilot signal inverted relative to a GPS timing signal in the signals from the NMC and determines a signal propagation delay offset from a time difference between receipt of the GPS timing signal and receipt of the inverted pilot signal;
- 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.
Dependencies are inferred from the claim text.