Interference alignment over asynchronous X networks

A symbol-asynchronous X network with time-invariant channel coefficients and single antenna nodes is considered. By employing the asynchronism in the design of the interference alignment, we achieve the upper bound for the total number of degrees of freedom of this network which is argued to be the same as that of the synchronous case. The asynchronism, which exists among the received signals at each receiver, results in inter-symbol-interference (ISI) among the transmitted symbols from different transmitters. This can provide the channel variation required for the vector alignment over the constant network with single antenna nodes.