Embodiments of the invention disclose a system and a method for reducing inter-carrier interference (ICI) in a network, wherein the network uses orthogonal frequency division multiplexing (OFDM). The method generates, in a transmitter, a diversified signal, wherein a diversified signal includes diversified elements representing data elements, such that each data element is represented by a number of diversified elements, wherein the number equals a degree of diversity. The diversified signal is modified based on an orthogonal matrix producing a spread signal, wherein columns of the orthogonal matrix are formed by vectors, wherein the vectors are orthogonal or quasi-orthogonal to each others, and the spread signal is transmitted in the network.