Capacity analysis and improvement for coexisting IEEE 802.16 systems in unlicensed spectrum

Today spectrum demand for wireless communication is tremendous and even keeps growing. In contrast, there are no blank spots in the spectrum map. Additional spectrum opportunities are available in unlicensed bands and so-called non-exclusively licensed bands which are currently made available. This non-exclusive spectrum can be exploited whenever a license holder is not active. These spectrum opportunities cannot be exclusively accessed so that multiple systems need to coexist. Existing MAC protocols need to be enhanced to allow a system to meet own Quality of Service (QoS) demands while allowing other coexisting systems to meet their QoS requirements. In this work, methods for capacity calculation known from cellular networks are extended and applied to a scenario of coexisting IEEE 802.16 (WiMAX) systems. Developed methods are used to evaluate enhancements for interference mitigation which lead to increased capacity.