Performance enhancement with dynamic frame aggregation in multi-rate infrastructure WLANs

The performance degradation caused by small-size packet and by low rate nodes has been observed and analyzed. In multi-rate WLANs, dominant small-size packets will cause the inefficient channel utilization, and performance anomaly problem happens for the presence of low rate nodes. In this paper, we proposed a novel algorithm named Dynamic frame aggregation (DFA) aimed for performance enhancement in multi-rate WLANs. Several techniques are proposed with DFA. Firstly, we redefine the maximum frame size of once transmission according to the data rate. Secondly, packets on both unidirectional and bidirectional link can be assembled based on the redefined maximum frame size. Using handshake frame such as Request-to-send (RTS)/Clear-to-send (CTS), the proportion index will be delivered. Mobile stations use this index to negotiate the actual frame size on up-link and down-link. This approach improves UDP and TCP performance. Analyses and simulation have executed in this paper to demonstrate the feasibility of this mechanism.