Orthonormal time-frequency shifting and spectral shaping communications method

Abstract

A wireless combination time, frequency and spectral shaping communications method that transmits data in convolution unit matrices (data frames) of N×N (N), where generally either all Ndata symbols are received over N spreading time intervals (each composed of N time slices), or none are. To transmit, the Nsized data frame matrix is multiplied by a first N×N time-frequency shifting matrix, permuted, and then multiplied by a second N×N spectral shaping matrix, thereby mixing each data symbol across the entire resulting N×N matrix (TFSSS data matrix). Columns from this NTFSSS data matrix are selected, modulated, and transmitted, on a one element per time slice basis. At the receiver, the replica TFSSS matrix is reconstructed and deconvoluted, revealing the data. The method can accommodate multiple users at once, can adapt to changing channel conditions, and is particularly useful for coping with channel impairments such as Doppler shifts.