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:
Jun. 10, 2003
Filed:
Jul. 30, 1999
Christopher Neville Tate, Bishops Stortford, GB;
Leslie Derek Humphrey, Harlow, GB;
Roger James Williamson, Much Hadham, GB;
Igor Kajetan Czajkowski, Bishop Stortford, GB;
Nortel Networks Limited, St. Laurent, CA;
Abstract
To facilitate acquisition of lock in a multiple sub-channel carrier scheme, a plurality of time-continuous pilots ( ) on known sub-channels are made available to an addressed unit across the frequency spectrum. The addressed unit is then able to select one of these pilots for training purposes and specifically for frequency and phase acquisition ( ). The selection is based, typically, on the pilot with either the best signal to noise ratio or the first pilot to satisfy the minimum quality requirements for effective training. Discontinuous carriers, of which there can be several, are then used to identify a symbol boundary at the addressed unit. Once acquisition has been established, the pilots can, if desired, be released to carry low-bit rate traffic, although it is preferable to retain pilot tones for use within the system. Selection of the pilot from one of a number of alternative sub-channels distributed through the spectrum therefore ensures accurate synchronisation irrespective of whether portions of the spectrum are generally noisy and unclean.