Opportunistic and hierarchical scheduling algorithms in OFDMA relaying networks

In this paper, we investigate efficient scheduling algorithms in OFDMA multihop relaying networks. The scheduling scheme is modeled as a multiple objective programming problem to maximize the overall capacity and the number of satisfied users under the minimum rate constraint per user. An improved priority (IPRI) algorithm is exploited with novel opportunistic function, which relies on capacity gain, user´s pathloss and starvation restrained (SR) mechanism. Moreover, a hierarchical greedy scheduling (HGS) algorithm is proposed by utilizing hierarchical steps to re-allocate parts of sub-channels from satisfied users to unsatisfied ones. A method is constructed as the re-allocate criterion in HGS for the multi-objective approach. Simulation results show that both IPRI and HGS could yield significant gains in terms of capacity and fairness.