Creation of Mixing Matrices for Signal Separation in Mobile Wireless Channels

Sets of linearly independent summations of RF signals have been studied as means to separate desired signals from interference and noise sources. The literature typically describes how to obtain and process these signal summations by spatially uncorrelated antenna elements, or in the case of spread spectrum encoded signals, by knowledge of their spreading codes. The existing literature however does not address all methods to increase the size of the signal summation set or the rank of the associated signal matrix. Exploitation of summations of this larger set will allow the separation of a larger number of signals, perform the separation with a smaller antenna array, and/or perform the signal separation in a more robust fashion. This paper will outline some techniques that may be used to produce such a richer set of signal sums.