Novel Scheduling Algorithms for Multimedia Service in OFDM Broadband Wireless Systems

Scheduling algorithms play a key role in overall system performance of broadband wireless systems (BWS) such as WLAN/WMAN. Maximal SNR (MaxSNR) and Round Robin (RR) are two conventional scheduling strategies which emphasize efficiency and fairness respectively. Proportional Fair (PF) algorithm provides tradeoff between efficiency and fairness and it has been well studied in TDMA and CDMA systems. In this paper, we apply the PF scheduling algorithm to IEEE 802.16a OFDM based BWS and call it OPF. In addition, we propose three algorithms for multimedia services: (1) Adaptive OPF (AOPF), (2) Multimedia AOPF (MAOPF) and (3) Normalized MAOPF (NMAOPF). Adaptive modulation and coding schemes are applied to combat the time varying nature of the wireless channels. System performances of all six algorithms are compared in terms of efficiency and fairness.. Joint PHY and MAC layer simulation results show that the proposed schemes provide better tradeoff between efficiency and fairness than conventional algorithms.