Özet:
Broadband Wireless Access (BWA) is an alternative to wired broadband like cable and xDSL. The IEEE 802.16 standard defines physical (PHY) and MAC layers of BWA systems. It has been called WiMAX (Worldwide Interoperability for Microwave Access) by industry. The uplink transmission of Subscriber Stations (SS) is determined by Base Station (BS) with sending Uplink Map (UL-MAP) in point to multipoint networks. The UL-MAP is sent in the downlink subframe and its size affects downlink data capacity. In this thesis, we introduce a new scheme to minimize MAC overhead due to UL-MAP size by using UL-MAP Extended Information Element (IE) to send future periodic fixed size grants for the connection whose scheduling service type is Unsolicited Grant Service (UGS). We evaluate our proposed scheme with simulations in OPNET 11.5 Modeler WiMAX module. Simulation results show that our proposed solution is superior to its conventional counterpart when there are high numbers of SSs with UGS connections in terms of cell throughput.
