The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 08, 2009
Filed:
Mar. 03, 2006
Jason Duggan, Nepean, CA;
Jason Duggan, Nepean, CA;
Nortel Networks Limited, St. Laurent, Quebec, CA;
Abstract
An initial ranging detection for an orthogonal frequency division multiple access (OFDMA) wireless communication system entails removing data sub-carriers from samples of an OFDMA signal in order to suppress inter-carrier interference (ICI) between the data sub-carriers and initial ranging sub-carriers, coherently summing the resulting samples to boost signal energy, and applying a sliding window FFT to the coherently summed samples for correlating each result of the sliding window FFT with each one of a set of predetermined codes. The suppression of ICI is done by removing the cyclic prefix, performing an FFT to transform to the frequency domain whereupon the initial ranging sub-carriers are zeroed. An IFFT is then performed to return to the time domain. The cyclic prefix is then added and the new samples are subtracted from the originally received samples. The resulting samples are free of ICI and can then be coherently summed to boost signal energy.