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:
Feb. 27, 2007
Filed:
Mar. 15, 2002
Constantinos B Papadias, Westfield, NJ (US);
Naresh Sharma, Budd Lake, NJ (US);
Constantinos B Papadias, Westfield, NJ (US);
Naresh Sharma, Budd Lake, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A method and apparatus for reducing the bit rate of multi-input systems that employ space-time coding by displacing in signal space the derivatives of a symbol. A mapped particular symbol is space-time coded to generate transmit-sequences having a phase-shifted version of the particular symbol, the phase-shifted version and the particular symbol differing in phase by an amount other than by 90°, 180°, and 270°. In one embodiment, the particular symbol represents a point in a first symbol constellation and the derivatives of the particular symbol represent points in a displaced symbol constellation. In another embodiment, the particular symbol and another symbol are space-time coded to form the transmit-sequences. The derivatives of the particular symbol represent points in a first symbol constellation and derivatives of the other symbol represent points of a second symbol constellation. The two constellations are displaced versions of each other. The displacement can be a phase shift and/or a change in amplitude. Illustratively, the two symbols are ones whose received versions interfere with each other after the two transmit-sequences are space-time decoded at the receiver. Displacing the derivatives of symbols reduces the bit error rate and thus increases the capacity of the system. Particularly, such a displacement increases the distance between symbols of a constellation whose points represent the combination of the derivatives of two the symbols.