Receiver for wireless transmission

摘要

A receiver for a single carrier frequency division multiple access (SC-FDMA) wireless transmission scheme comprises:a. A frequency domain equalizer such as a Minimum Mean Square Error (MMSE) equalizer 52 that introduces inter-symbol interference into the received signal;b. A transformation device 56 for transforming the equalized signal from the equalizer to the time domain; andc. A plurality of decision feedback equalizers 59 comparing a feedforward filter to whiten noise in the signal, a decision device to determine output symbols from the output of the feedforward filter, and a feedback filter to receive previous symbol estimates from the decision device and to subtract them from the output of the feedforward filter to reduce inter-symbol interference; andd. A combiner 70 for combining the outputs of the decision feedback equalizers. Different decision feedback equalizers receive signals from the transformation device in different temporal orders and/or with different time delays in order to reduce error propagation from the decision feedback equalizers in the output of the receiver. The filter coefficients of the feedforward and feedback filters, which each have filter coefficients forming an upper triangular matrix, are calculated by means of a Cholesky factorization calculator 74 which may be very computationally intensive. The number of multiplications required per iteration can be reduced from millions to tens of thousands by a fast Cholesky factorization (FCF) algorithm, and reduced further to the order of hundreds by extracting redundant calculations.