Performance Evaluation of the GCR Block ACK Mechanism in IEEE 802.11aa Networks

The growing demand for multimedia services has gradually made video streams major traffic sources in the Internet. This trend introduces higher demand for IEEE 802.11 wireless networks since such wireless networks are intrinsically inefficient to carry video streams. As a solution to improve system efficiency, a new standard, 802.11aa, is developed by introducing the Groupcast with Retries (GCR) scheme, one of the most important features in this amendment. In this paper, we analyse the throughput performance of the GCR scheme for one of the transmission mechanisms in 802.11aa networks based on a Markov model. Numerical results demonstrate that the successful retransmission probability will be reduced with a larger number of receiving terminals; but it can be increased by reducing the transmission block size. Furthermore, the system throughput can also be improved by configuring the size of the initial transmission block.