Date Added: Feb 2012
This paper considers the problem of energy-efficient transmission in multi-flow multi-hop cooperative wireless networks. Although the performance gains of cooperative approaches are well known, the combinatorial nature of these schemes makes it difficult to design efficient polynomial-time algorithms for joint routing, scheduling and power control. This becomes more so when there is more than one flow in the network. It has been conjectured by many authors, in the literature, that the multi-flow problem in cooperative networks is an NP-hard problem.