US 2007/0177699 A1 · Interpolation processing for enhanced signal acquisition

Abstract

The present invention relates to methods and systems for enhanced signal acquisition through cross-ambiguity function (CAF) interpolation. In one aspect, the present invention provides methods and systems for CAF interpolation. In an embodiment, a first CAF generated using a low input sampling rate (e.g., 1 sample/chip) is interpolated to generate a second CAF having a higher sample per chip rate. By lowering the initial input sampling rate, cost and complexity of initial synchronization processing can be significantly reduced at the receiver. In another aspect, coherent and non-coherent interpolation methods and systems are provided for time and frequency CAF interpolation. Low cost and low complexity implementations of these methods and systems are also provided with associated CAF peak detection methods and systems.

Claims20

Dependent claims

A method for signal acquisition, comprising:

(a) receiving a sampled complex baseband signal representative of a complex envelope of a received signal;
(b) low-pass filtering the received sampled signal to generate a filtered sampled signal;
(c) decimating the filtered sampled signal to reduce a sample rate thereof;
(d) cross-correlating the filtered sampled signal in time and frequency with a locally-generated replica thereof to generate a sampled cross ambiguity function (CAF) having samples spaced in time according to the sample rate of the filtered sampled signal;
(e) interpolating the sampled CAF in time and frequency to generate a second CAF, wherein the second CAF has at least two times the number of samples as the sampled CAF;
and
(f) detecting a peak value in the second CAF, wherein the peak value corresponds to an estimated pair of time and frequency offsets between the filtered sampled signal and the locally generated replica.

4 more elements

Dependencies are inferred from the claim text.

Interpolation processing for enhanced signal acquisition

Life of this patent

Interpolation processing for enhanced signal acquisition

Life of this patent

Abstract

Claims20