Subcarrier and power allocation in relay-assistant OFDMA cellular system

In this paper, resource allocation problems in a downlink relay-assistant OFDMA cellular system are studied. Amplify-and-forward relaying strategy is utilized at each relay station to assist signal transmission while half-duplex transmission protocol is adopted. A joint optimization of subcarrier-pairing in two consecutive time slots and power allocation on each subcarrier in each time slot is investigated through a capacity maximization problem constrained on independently available power at BS and RS. Some fundamental principles to achieve optimality are given while a few subcarrier and power allocation algorithms are proposed. The performance of these resource allocation algorithms is evaluated by computer simulation.