Virtually Dedicated Resource Allocation for VoIP Traffic in the Downlink Mobile WiMAX System With Hybrid ARQ

This paper introduces the concept of a virtually dedicated resource allocation (VDRA) scheme that significantly reduces signaling overhead for accommodating low/medium data traffic, including real-time VoIP traffic. The basic concept of the VDRA scheme is to allocate the virtually dedicated resource to each user and to use the resource only when there are data to be transmitted. The performance of the proposed VDRA scheme in downlink is analyzed using a queuing system with hybrid automatic repeat request retransmissions to derive the distribution of packet delay and user capacity. In addition, the analytical results are verified through simulation results. The performance of the proposed VDRA scheme is compared with the persistent allocation scheme and the dynamic scheduling scheme. The proposed VDRA scheme yields a 15%-28% increase in user capacity and a 26%-69% decrease in the size of signaling overhead compared with the dynamic scheduling scheme. The proposed VDRA scheme yields slightly better performance in terms of user capacity and signaling overhead than the persistent allocation scheme for accommodating even voice over Internet Protocol (VoIP) traffic. In addition, the proposed VDRA scheme yields much smaller mean packet delay performance than the persistent allocation scheme. Moreover, the application of the persistent allocation (PA) scheme is limited to only real-time periodic VoIP traffic. On the other hand, the applicability of the proposed VDRA scheme is much wider than the PA scheme, including periodic and nonperiodic traffic, as well as real-time and non-real-time traffic, because the proposed VDRA scheme requires no constraint to the input traffic.