Methods and Apparatus for Accurately Determining Signal Time of Arrival

A mobile communication device, comprising:

• a receiver configured to receive a signal in accordance with a correlation function to produce a stream of correlation samples including a peak sample, a plurality of pre-peak samples, and a plurality of post-peak samples, wherein the time of arrival of the signal corresponds to a timing of a peak of the correlation function, which lies in a vicinity of the peak sample;
• a storage device configured to store a curve matching table comprising a plurality of sets of values, each of the sets of values representing discrete points of a correlation function having a peak at a respective different time shift relative to the timing of the peak sample, wherein the plurality of sets of values includes first sets of values to be matched with a first set of samples from the stream of correlation samples and second sets of values to be matched with a second set of samples from the stream of correlation samples;
• a processor configured to:
• match each of the first sets of values to the first set of samples, the first set of samples including no post-peak samples;
• match each of the second sets of values to the second set of samples, the second set of samples including at least one post-peak sample, wherein one set of values among the first and second sets of values produces a best match;
• and determine the time of arrival of the signal based on a timing of the peak of the correlation function represented by the one set of values that produced the best match.

A computer readable medium storing instructions, that when executed by a computer, cause the computer to perform functions of:

• receiving a stream of correlation samples resulting from correlating a received signal in accordance with a correlation function, the correlation samples including a peak sample, a plurality of pre-peak samples, and a plurality of post-peak samples, wherein the time of arrival of a signal corresponds to a timing of a peak of the correlation function, which lies in a vicinity of the peak sample;
• retrieving data from a curve matching table comprising a plurality of sets of values, each of the sets of values representing discrete points of a correlation function having a peak at a respective different time shift relative to the timing of the peak sample, wherein the plurality of sets of values includes first sets of values to be matched with a first set of samples from the stream of correlation samples and second sets of values to be matched with a second set of samples from the stream of correlation samples;
• matching each of the first sets of values to the first set of samples, the first set of samples including no post-peak samples;
• matching each of the second sets of values to the second set of samples, the second set of samples including at least one post-peak sample, wherein one set of values among the first and second sets of values produces a best match;
• and
• determining the time of arrival of the signal based on timing of the peak of the correlation function represented by the one set of values that produced the best match.