Performance analysis of VoIP according to relay capability in OFDMA-based systems

We consider a relay-assisted wireless communication system where relays are given the capability of scheduling function. We evaluate and compare the performances of voice over internet protocol (VoIP) in orthogonal frequency division multiple access (OFDMA) systems where two different scheduling capabilities of relays are employed in each system. In the system with relays that have the scheduling capability, channel-resource allocation is not performed efficiently, which results in degraded performance of the system compared to the system with the relays that do not have the scheduling capability as shown in the simulation result.