A SLIPD method is proposed to design the first distributed
algorithm (Algorithm 1) for the case that each relay
is equipped with single receive antenna. Algorithm 1 can
yield a global optimal solution to the preceding power
minimization problem. Then the SLIPD method combined
with successive convex approximations is further applied
to the design of the second distributed algorithm (Algorithm
2) for the case of multiple receive antennas at each
relay, that can yield at least a local optimal solution of the power minimization problem.