This paper is focused on the problem of optimizing the aggregate throughput of the distributed coordination function (DCF)\r\nemploying the basic access mechanism at the data link layer of IEEE 802.11 protocols. We consider general operating conditions\r\naccounting for both nonsaturated and saturated traffic in the presence of transmission channel errors, as exemplified by the packet\r\nerror rate Pe. The main clue of this work stems from the relation that links the aggregate throughput of the network to the packet\r\nrate ? of the contending stations. In particular, we show that the aggregate throughput S(?) presents two clearly distinct operating\r\nregions that depend on the actual value of the packet rate ? with respect to a critical value ?c , theoretically derived in this work. The\r\nbehavior of S(?) paves the way to a cross-layer optimization algorithm, which proved to be effective for maximizing the aggregate\r\nthroughput in a variety of network operating conditions. A nice consequence of the proposed optimization framework relies on\r\nthe fact that the aggregate throughput can be predicted quite accurately with a simple, yet effective, closed-formexpression. Finally,\r\ntheoretical and simulation results are presented in order to unveil, as well as verify, the key ideas.
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