  Most of the deployed IEEE 802.11e Wireless Local Area Networks (WLANs) use
infrastructure Basic Service Set (BSS) in which an Access Point (AP) serves as
a gateway between wired and wireless domains. We present the unfairness problem
between the uplink and the downlink flows of any Access Category (AC) in the
802.11e Enhanced Distributed Channel Access (EDCA) when the default settings of
the EDCA parameters are used. We propose a simple analytical model to calculate
the EDCA parameter settings that achieve weighted fair resource allocation for
all uplink and downlink flows. We also propose a simple model-assisted
measurement-based dynamic EDCA parameter adaptation algorithm. Moreover, our
dynamic solution addresses the differences in the transport layer and the
Medium Access Control (MAC) layer interactions of User Datagram Protocol (UDP)
and Transmission Control Protocol (TCP). We show that proposed Contention
Window (CW) and Transmit Opportunity (TXOP) limit adaptation at the AP provides
fair UDP and TCP access between uplink and downlink flows of the same AC while
preserving prioritization among ACs.
