Date Added: Jan 2013
In wireless cooperative Orthogonal Frequency Division Multiple-Access (OFDMA) networks, it is important to adapt the transmission strategies for each user according to the network channel dynamics in order to optimize the overall system performance. The adaption involves transmission mode selection (a user can choose from direct or cooperative transmission), subcarrier assignment, subcarrier pairing (the incoming and outgoing subcarriers at the relay for cooperative transmission need to be matched), relay selection, as well as power allocation and hence is highly challenging. Many previous works only consider a subset of the adaptation. In this paper, the authors tackle the joint optimization problem using a network flow approach.