Security overhead and performance for aggregation with fragment retransmission (AFR) in very high-speed wireless 802.11 LANs

In this paper, we study the overhead introduced by the advanced encryption standard cipher in the context of wireless LANs, specifically at the medium access control layer, as described in the 802.11 standard developed by the 802.11n task group. The advanced encryption standard is incorporated into existing aggregation schemes for 802.11 wireless LANs in order to achieve secure transmission of frames. We compute the maximum throughput, optimal frame, and fragment sizes which can be achieved in this context and compare them to the optimal values when encryption is not used. We evaluate the delay performance of such a scheme in the context of encryption and study asymptotic properties of the medium access control layer efficiency, expected frame size, and throughput.