An equalizer for equalizing a composite signal originating from a given number L of simultaneous data streams, hereinafter layers, able to be received over a communication channel, on a given number M of antennas, at one or more radio units, in a wireless communication system, the equalizer comprising: - a processing unit such as a processor; and, - a memory unit operably coupled to the processing unit; wherein the processing unit is arranged to produce an estimate data representing a transmitted signal vector x̃ of size L, associated with an estimation of a transmitted signal received at the one or more radio units, based on: - a received signal data representing a received signal vector Y of size N × 1, associated with the received composite signal; - a channel response estimate data representing a channel estimation matrix H̃ of size N × L, associated with a channel response estimation of the communication channel; - a layer covariance data representing a layer covariance matrix C of size L × L, associated with the layers able to be received over the communication channel; and, - a noise covariance data representing a noise covariance matrix S of size N × N, associated with a noise level present at the antennas; characterized in that, when the composite signal is received on a given number N of antennas, where M is greater than N, the processing unit is arranged to: - increase the dimension associated with the given number N of antennas, to the given number M of antennas, at one or more similar positions with respect to Y, H̃ and S -1, thereby producing Y _ inc, H̃ _ inc and S -1 _ inc, respectively, wherein S -1 denotes the inverse matrix of S; - add padding elements to Y_inc, H̃ _ inc and S -1 _ inc, at the one or more similar positions, thereby producing Y_pad, H_pad and S -1 _ pad, respectively; and, - produce the estimate data representing the transmitted signal vector x̃ based on Y _ pad, H̃_pad, C and S − 1 ̃ _pad. - a processing unit such as a processor; and, - a memory unit operably coupled to the processing unit; - a received signal data representing a received signal vector Y of size N × 1, associated with the received composite signal; - a channel response estimate data representing a channel estimation matrix H̃ of size N × L, associated with a channel response estimation of the communication channel; - a layer covariance data representing a layer covariance matrix C of size L × L, associated with the layers able to be received over the communication channel; and, - a noise covariance data representing a noise covariance matrix S of size N × N, associated with a noise level present at the antennas; characterized in that, when the composite signal is received on a given number N of antennas, where M is greater than N, the processing unit is arranged to: - increase the dimension associated with the given number N of antennas, to the given number M of antennas, at one or more similar positions with respect to Y, H̃ and S -1, thereby producing Y _ inc, H̃ _ inc and S -1 _ inc, respectively, wherein S -1 denotes the inverse matrix of S; - add padding elements to Y_inc, H̃ _ inc and S -1 _ inc, at the one or more similar positions, thereby producing Y_pad, H_pad and S -1 _ pad, respectively; and, - produce the estimate data representing the transmitted signal vector x̃ based on Y _ pad, H̃_pad, C and S − 1 ̃ _pad. - increase the dimension associated with the given number N of antennas, to the given number M of antennas, at one or more similar positions with respect to Y, H̃ and S -1, thereby producing Y _ inc, H̃ _ inc and S -1 _ inc, respectively, wherein S -1 denotes the inverse matrix of S; - add padding elements to Y_inc, H̃ _ inc and S -1 _ inc, at the one or more similar positions, thereby producing Y_pad, H_pad and S -1 _ pad, respectively; and, - produce the estimate data representing the transmitted signal vector x̃ based on Y _ pad, H̃_pad, C and S − 1 ̃ _pad.