A communication unit for performing soft-decision demodulation comprising a receiver, wherein the receiver is arranged to receive a transmitted signal conveying a first set of bits comprising k bits used as an index to select one from a set of 2 k possible signals, wherein the set of 2^k possible signals is provided by a set of 2^k orthogonal communication sequences and the receiver comprises: a demodulator comprising a bank of 2 k correlators and configured to: detect a transmission of each possible transmitted signal, and output 2 k magnitudes of correlator outputs, based on the detected possible transmitted signals, by the bank of 2 k correlators as a first set of inputs; wherein the communication unit is characterized by: a de-mapper circuit coupled to the demodulator and configured to receive the first set of inputs and: determine statistics derived from two aggregated correlator output magnitude distributions of the first set of inputs, wherein a first aggregated correlator output magnitude distribution approximates an aggregation of 2 k distributions of the output magnitudes of the bank of 2 k correlators when a corresponding one of the 2 k possible signals was selected as the transmission signal and wherein a second aggregated correlator output magnitude distribution approximates an aggregation of a remaining 2 2k -2 k distributions of the output magnitudes; and calculate therefrom and output a first set of aposteriori soft bits comprising k soft bits. a demodulator comprising a bank of 2 k correlators and configured to: detect a transmission of each possible transmitted signal, and output 2 k magnitudes of correlator outputs, based on the detected possible transmitted signals, by the bank of 2 k correlators as a first set of inputs; detect a transmission of each possible transmitted signal, and output 2 k magnitudes of correlator outputs, based on the detected possible transmitted signals, by the bank of 2 k correlators as a first set of inputs; wherein the communication unit is characterized by: a de-mapper circuit coupled to the demodulator and configured to receive the first set of inputs and: determine statistics derived from two aggregated correlator output magnitude distributions of the first set of inputs, wherein a first aggregated correlator output magnitude distribution approximates an aggregation of 2 k distributions of the output magnitudes of the bank of 2 k correlators when a corresponding one of the 2 k possible signals was selected as the transmission signal and wherein a second aggregated correlator output magnitude distribution approximates an aggregation of a remaining 2 2k -2 k distributions of the output magnitudes; and calculate therefrom and output a first set of aposteriori soft bits comprising k soft bits. determine statistics derived from two aggregated correlator output magnitude distributions of the first set of inputs, wherein a first aggregated correlator output magnitude distribution approximates an aggregation of 2 k distributions of the output magnitudes of the bank of 2 k correlators when a corresponding one of the 2 k possible signals was selected as the transmission signal and wherein a second aggregated correlator output magnitude distribution approximates an aggregation of a remaining 2 2k -2 k distributions of the output magnitudes; and calculate therefrom and output a first set of aposteriori soft bits comprising k soft bits.