  In today's WLANs, scheduling of packet transmissions solely relies on the
collision and success a station may experience. To better support traffic
differentiation in dense WLANs, in this paper, we propose a distributed
reservation mechanism for the Carrier Sense Multiple Access Extended Collision
Avoidance (CSMA/ECA) MAC protocol, termed CSMA/ECA-DR, based on which stations
can collaboratively achieve higher network performance. In addition, proper
Contention Window (CW) will be chosen based on the instantaneously estimated
number of active contenders in the network. Simulation results from dense
scenarios with traffic differentiation demonstrate that CSMA/ECA-DR can greatly
improve the efficiency of WLANs for traffic differentiation even with large
numbers of contenders.
