Energy-Saving Strategies by Extending Unavailability Interval Approach for Multiple Traffic Classes in IEEE 802.16e

IEEE 802.16e standard have been designed for both delay sensitive and delay tolerant applications. This paper presents energy-saving strategies by extending unavailability interval for multiple power saving classes simultaneously. The proposed model allows mobile stations to dynamically adopt multiple sleep mode operation or multiple partial sleep mode operation based on the buffer status of power saving class I and II. We set up partial sleep interrupt function which decides whether to stay in multiple partial sleep state or busy state to enhance the response time in real time traffic. Various performance indices of the system are presented. A cost model is formulated to determine the optimal values of various parameters at minimum cost using quadratic fit search method. It is shown numerically that the proposed model improves the system performance efficiently. Key-Words: IEEE 802.16e, downlink, sleep mode, accessible batch, multiple power saving classes, unavailability interval.