Measurement of baseband timing in a spread spectrum communications system
AssigneeTerrace Communications Corporation
InventorNathan Hays
Life of this patent
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Abstract
Systems, apparatuses, and methods for providing timing estimates of received signals are disclosed. In one embodiment, sub-chip timing in spread spectrum signals can be achieved without requiring oversampling in the receiver. A transmitter can adjust the timing of certain transmitted symbols by a fraction of a chip time from an expected time, and send the mistimed symbols to a receiver. The output of the receiver's de-spreading correlator can show different magnitudes for wedge symbols with different timing errors. By setting some symbols early and some late, and by taking the difference between their magnitudes, a transfer function between the result and a timing error can be determined.
Claims20
A method for determining a timing error of a signal received in a receiver from a transmitter, the method comprising:
- receiving, from the transmitter, first and second symbols that are transmitted off-peak in association with the signal following timings of the transmitter, wherein the transmitter is one of a plurality of transmitters that are separate devices from the receiver and that are configured to transmit to the receiver;
- detecting the first and second symbols by sampling the first and second symbols received from the transmitter, wherein the sampling is performed at a rate approximately equal to a chip rate that is synchronized between the transmitter and the receiver;
- calculating a timing error result for the received signal by comparing magnitudes of the detected first and second symbols;
- and
- sending the timing error result from the receiver to the transmitter to allow the transmitter to modify subsequent transmissions from the transmitter.
An apparatus configured to determine a timing error of a signal received in the apparatus from a transmitter, the apparatus comprising:
- a radio-frequency (RF) receiving circuit for receiving, from the transmitter, first and second symbols that are transmitted off-peak in association with the signal following timings of the transmitter, wherein the transmitter is one of a plurality of transmitters that are separate devices from the apparatus and that are configured to transmit to the apparatus, wherein the signal comprises an RF signal;
- a detector for detecting the first and second symbols by sampling the first and second symbols received from the transmitter, wherein the sampling is performed at a rate approximately equal to a chip rate that is synchronized between the transmitter and the apparatus;
- a comparator for comparing magnitudes of the detected first and second symbols to calculate a timing error result for the received signal;
- and
- a sender for sending the timing error result from the apparatus to the transmitter to allow the transmitter to modify subsequent transmissions from the transmitter.
A system for determining a timing error of a signal received in a receiver from a transmitter, the system comprising:
- means for receiving, from the transmitter, first and second symbols that are transmitted off-peak in association with the signal following timings of the transmitter, wherein the transmitter is one of a plurality of transmitters that are separate devices from the receiver and that are configured to transmit to the receiver;
- means for detecting the first and second symbols by sampling the first and second symbols received from the transmitter, wherein the sampling is performed at a rate approximately equal to a chip rate that is synchronized between the transmitter and the receiver;
- means for calculating a timing error result for the received signal by comparing magnitudes of the detected first and second symbols;
- and
- means for sending the timing error result from the receiver to the transmitter to allow the transmitter to modify subsequent transmissions from the transmitter.
Dependencies are inferred from the claim text.