Patent ID: 7173973
Filing Date: 2007-02-06
Classification: H04L

Abstract:
1. A receiver for receiving data and pilot symbols simultaneously over multiple channels comprising: at least one antenna; a demodulator coupled to an output of the antenna for demodulating received symbols in accordance with a multi-carrier transmission technique, a channel estimator coupled to the demodulator for estimating a channel of a multi-carrier system using received pilot symbols; a storage medium for storing a multi-level signal constellation defining C points, of which at least one point defines a first level and a plurality of points define a second level, and a minimum inter-level distance between points is based on a maximized minimum difference between conditional probability distributions; and a mapper coupled to the demodulator and to the storage medium for converting the demodulated symbols to a plurality of data signals that each alone or in combination correspond to a constellation point wherein the demodulator determines a maximum likelihood conditional probability distribution of the received symbols and wherein the conditional probability distribution is such that the detector maximizes over at least two possible values for S i to find a transmitted symbol wherein S i comprises a transmitted signal vector, Ĥ i comprises a channel estimate matrix, X i comprises a received signal vector, {tilde over (H)} i comprises an estimation error matrix at an i th frequency bin, E {tilde over (H)} is an error estimation matrix, and σ E is the estimation variance at each frequency bin.