Uplink scheduling in IEEE 802.16 WMAN

Abstract

IEEE 802.16 WMAN technology has been proposed to overcome the drawbacks of WLANs and cellular networks. It has been paid wide attention since it covers much larger area than WLAN while supporting high transmission rate. Besides, it provides various QoS scheduling for supporting heterogeneous traffic including legacy voice traffic, VoIP (Voice over IP), multimedia streams and the Internet data traffic. In IEEE 802.16 networks, a bandwidth request-grant mechanism is used to accommodate various QoS requirements of heterogeneous traffic. When a subscriber station (SS) wants to send data, it first needs to send a bandwidth request message to the corresponding base station (BS). Upon receiving the request, the BS grants an appropriate amount of bandwidth to the SS based on an uplink scheduling scheme. There are four service classes defined based on their bandwidth request-grant mechanisms as follows: unsolicited grant service (UGS), real-time polling service (rtPS), non-real-time polling service (nrtPS), and best-effort (BE) service. Among those four service classes, it is expected that the BE class will be the first one to be serviced due to the following practical reasons: (a) Implementation overhead is too high whereas there is no currently available such service that requires the QoS; and (b) Even if the access network supports the QoS, end-to-end QoS support is not supported eventually since the Internet does not provide any QoS scheme currently. WiBro service in South Korea, which is the first commercial service of IEEE 802.16, supports BE class only at this time. The objective of this thesis is to present comprehensive performance analysis of BE traffic in IEEE 802.16 networks. There have been several studies on performance of IEEE 802.16 networks, but they mostly focus on the physical layer and the overall MAC protocol. In the first part of this thesis, we focus on performance of BE traffic associated with more specific scheduling schemes based on re...