Exploiting MAC flexibility in WiMAX for media streaming

The IEEE 802.16 standard (commonly known as WiMAX), which has emerged as a broadband wireless access technology, is capable of delivering very high data rates. However, providing performance guarantees to delay sensitive applications like streaming media is still a challenge. We study the media access control (MAC) layer of WiMAX and exploit its flexible features to construct MAC packet data units (MPDU) dynamically. The sizes of the MPDUs are constantly modified based on channel state information. The desired payload is obtained either by aggregation or fragmentation of the upper layer data units. The robustness of MPDUs is also made tunable by means of cyclic redundancy code bits. We consider both the scenarios - with and without feedback. We adhere to the 802.16 specifications and propose adapting the MPDU length for streaming media for better performance. Three metrics are defined: restore probability; goodput; dropping probability. Simulation experiments are conducted which show the performance enhancements of the proposed ARQ-enabled adaptive algorithm in terms of these three metrics.