MCS selection algorithms for a persistent allocation scheme to accommodate VoIP services in IEEE 802.16e OFDMA system

In IEEE 802.16e OFDMA system, the system capacity for accommodating VoIP traffic with small-sized PDUs is severely reduced due to a large amount of signalling overhead. In order to mitigate this problem, the IEEE 802.16 maintenance group has recently proposed a persistent allocation scheme to increase the voice over IP (VoIP) system capacity. However, it is difficult to use the conventional modulation and coding scheme (MCS) selection algorithms, which are based on instantaneous SINR, for the persistent allocation scheme. In this paper, we propose MCS selection algorithms which are effective for using radio resources considering a hybrid ARQ retransmission mechanisms while satisfying given QoS requirements for the persistent allocation scheme. Numerical results show that the proposed algorithms are effective for utilizing radio resources efficiently while satisfying given QoS requirements.