Spatio-temporal precoding for faster-than-Nyquist signal transmissions

A method for sending a first number of data messages, each data message comprising blocks having a second number of data symbols, simultaneously from a data transmission device to a number of receivers, wherein the number of receivers is equal to the first number of data messages, and wherein each data message is addressed to one of the receivers, over a Multiple Input Single Output, MISO, channel, the channel introducing inter-user interference on transmitted signals, the method comprising the following steps:

• a) selecting, using selection means, a signal constellation associated with a digital modulation scheme, the signal constellation comprising a plurality of constellation points, wherein each constellation point is associated with a data symbol and with a corresponding detection region;
• b) for the data symbols of each set of blocks, wherein a set of blocks comprises one block from each one of the first number of data messages,
• i) computing corresponding precoded symbols that correspond to the data symbols in the set of blocks;
• ii) modulating a carrier signal in accordance with said digital modulation scheme, to represent a modulated signal for each of said precoded symbols;
• iii) generating signal pulses corresponding to each of said modulated signals;
• iv) transmitting said signal pulses on said MISO channel;
• c) wherein the signal pulses corresponding to consecutive sets of blocks are transmitted at a signaling rate that is higher than the Nyquist rate associated with said signal pulses, thereby introducing inter-symbol interference;
• and wherein the computation of said precoded symbols depends on said signaling rate so that, after suffering said inter-user interference and said inter-symbol interference during transmission, the data symbols of the blocks from each set of blocks, received at the respective receivers, lie in their corresponding detection regions.