Method and apparatus for multi-path delay spread detection in wideband CDMA systems
AssigneeNational Semiconductor Corporation
InventorsKarim Nassiri Toussi, Rajaram Subramoniam, Huoy-Bing Lim, Debarag Banerjee
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Abstract
A fast, low-complexity detection scheme for determining the delays and gains of different propagation paths (i.e., multi-paths) of a received WCDMA signal. The method utilizes a continuous pilot channel that is scrambled by an known pseudo-random sequence. The received signal is provided to a multi-path searcher that passes the received signal through a matched filter with a specified number of taps. The matched filter correlates the received signal with the pilot channel. The multi-path gain and delay detection is then performed, and the delays and gains are reported for use in the WCDMA system.
Claims23
A method for multi-path searching in a mobile device such that the mobile device detects delays and gains of different propagation paths for a received signal, the method for the mobile device comprising:
- correlating data corresponding to a first one of the propagation paths of the received signal with a conjugate of a pilot channel sequence;
- repeating the correlation for other propagation paths of the received signal, wherein the other propagation paths correspond to a first set of propagation paths that also includes the first one of the propagation paths;
- coherently accumulating results corresponding to the correlation for the first set of propagation paths;
- calculating square-magnitudes of the coherently accumulated results corresponding to the first set of propagation paths;
- and
- comparing the calculated square-magnitudes of the coherently accumulated results corresponding to the first set of propagation paths to a threshold to identify first search results for the first set of propagation paths from the square-magnitudes of the first set of propagation paths that surpass the threshold, wherein the first search results include corresponding delays and gains for the first set of propagation paths.
A method for multi-path searching in a mobile device such that the mobile device detects delays and gains of different propagation paths of a received signal, the method for the mobile device comprising:
- generating a pilot channel chip sequence starting from a pilot symbol boundary;
- loading tap coefficients of a matched filter with a conjugate of the pilot channel sequence;
- operating the matched filter to correlate a first set of data with the conjugate of the pilot channel sequence to produce a first set of results corresponding to the first set of data, wherein the first set of data is associated with propagation paths of the received signal;
- operating the matched filter to correlate a second set of data with the conjugate of the pilot channel sequence to produce a second set of results corresponding to the second set of data, wherein the second set of data is associated with propagation paths for the received signal;
- coherently adding the first set of results with the second set of results to provide a first coherent accumulation;
- calculating a first set of square-magnitudes for the first set of results and the second set of results with the first coherent accumulation, wherein the calculated first set of square magnitudes each have a corresponding time indexed location;
- and
- comparing the calculated first set of square-magnitudes to a threshold to identify search results, wherein the time-indexed locations of the calculated first set of square-magnitudes that surpass the threshold identify the delays and gains of the first and second sets of data associated with the propagation paths.
An apparatus for multi-path searching such that the apparatus detects delays and gains of different propagation paths for a received signal, comprising:
- a means for correlating data corresponding to a first one of the propagation paths of the received signal with a conjugate of a pilot channel sequence;
- a means for repeating the correlation for other propagation paths of the received signal, wherein the other propagation paths correspond to a first set of propagation paths that also includes the first one of the propagation paths;
- a means for coherently accumulating results from the correlation of the first set of propagation paths;
- a means for calculating the square-magnitudes of the coherently accumulated results from the correlation of the first set of propagation paths;
- and
- a means for comparing the calculated square-magnitudes of the coherently accumulated results from the correlation of the first set of propagation paths to a threshold and identifying search results for the first set of propagation paths from the calculated square-magnitudes of the coherently accumulated results from the correlation of the first set of propagation paths that surpass the threshold, wherein the search results for the first set of propagation paths identify delays and gains of the first set of propagation paths.
Dependencies are inferred from the claim text.