A New Scheduler for IEEE 802.16 with Delay Bound Guarantee

The IEEE 802.16 Working Group on Broadband Wireless Access is developing the standard for broadband wireless access networks in Metropolitan Area Network (MAN), also know as WiMAX. One of the features of the 802.16 MAC layer is that it is designed to differentiate service among traffic categories with different multimedia requirements. Based on these assumptions and considering that the standard does not specify a scheduling algorithm, an original analytical model was proposed based on Latency-Rate (LR) server theory and system characteristics specified by the standard for systems using the WirelessMAN-OFDM (Orthogonal Frequency Division Multiplexing) air interface. The proposed scheduling algorithm for the uplink traffic guarantees a bounded delay for the IEEE 802.16 and the Time Frame (TF) is calculated to maximize the number of allocated stations taking into account delay bound parameters. We show that it is possible to obtain worst-case performance guarantee on delay. Properties of the proposal are investigated theoretically. We present a set of simulation with both Constant Bit Rate (CBR) and Variable Bit Rate (VBR) flows and performance comparisons among different TFs. The results show that the delay upper bound can be achieved for a large range of networks load with bandwidth optimization.