Two-Way Relaying Over OFDM: Optimized Tone Permutation and Power Allocation
The authors consider an amplify-and-forward scheme for two-way relaying over OFDM, in which two nodes wish to exchange information via a relay. Assuming full channel knowledge, they perform power allocation for the relay and both information exchanging nodes, as well as tone permutation at the relay, so as to maximize the sum capacity. A dual decomposition technique is employed for power allocation, while a greedy approach is proposed for tone permutation. In particular, they explore an interesting water-filling behavior displayed by this power allocation solution. Numerical results demonstrate that substantial capacity gains are achieved by implementing the two proposed solutions, either individually or successively.