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. 15, 1998
Filed:
Jun. 21, 1996
Xiang-Gen Xia, Westlake Village, CA (US);
Hughes Electronics Corporation, El Segundo, CA (US);
Abstract
A vector trellis coded modulation scheme (VTCM) is accomplished by blocking input samples into a sequence of input vectors of length L, vector convolutional coding the input vectors to map K input vectors into N output vectors and modulating the output vectors into symbols from an expanded alphabet. In a first case, each output vector is modulated to a different symbol thereby improving coding gain while maintain bandwidth efficiency. In a second case, blocks of N output vectors are modulated to one symbol thereby improving bandwidth efficiency by a factor of N while maintain coding gain. A polyphase/multirate representation of the vector convolutional codes is preferably used to generated the vector convolutional codes. In general, a computer search can be employed to find the polyphase coefficients that define the set of vector convolutional codes. When the input and output vectors have the same length, known scalar-valued convolutional codes are blocked to generate the vector convolutional codes. This provides good modulation codes without having to perform a computer search.