Scheduling Performance of Real Time Service in Multiuser OFDM System

In multiuser OFDMA system, multiuser diversity gain can be achieved by channel aware subcarrier and power allocation, and most work in this field is focused on the none-real time service. For real time (RT) service, not only the data rate, but also the packet delay should be guaranteed. In this paper, the multiuser subcarrier allocation is investigated for real time service. By exploiting the queue status information and channel state information (CSI), the delay sensitive service is expected to be served well. In this paper, modified largest weighted delay first (M-LWDF), quality guaranteed (QG) scheduling algorithms based on channel and queue aware are proposed for real time service in multiuser OFDMA system, and compared with packet loss ratio (PLR) algorithm. From the simulation results, these algorithms almost have the same performance when system load is low, when the radio resource is enough to offer service for video users; when the system load increases, the performance difference becomes larger. The modified M-LWDF has the best performance, while QG has a better system throughput than PLR, but a worse user drop ratio.