Before revision:  Simulation results are presented to demonstrate the performance gain of the jointly optimal solution over some suboptimal alternatives  .
After revision:  Simulation results are presented to demonstrate the performance gain of the jointly optimal solution over some suboptimal alternatives . It is also observed that more gain is obtained from optimal channel pairing than optimal power allocation through judiciously exploiting the variation among multiple channels. Impact of the variation of channel gain, the number of channels, and the number of hops on the performance gain is also studied through numerical examples .