A cooperative amplify-and-forward (AF) wireless relay scheme consisting of M sources, N relays, and L destinations all equipped with a single antenna was studied in this thesis. The main objective was to design jointly and iteratively the closed form of the minimum mean square error (MMSE)-based source precode and relay amplifying matrices under a jamming environment with various power constraints: (1) transmit, (2) aggregate, (3) source, and (4) relay. With the derived optimal source precode and relay amplifying matrices, the jamming influence of various power constraints on system performance were examined numerically using Monte-Carlo simulations.