Abstract: It is found that the rev erse ACK ( acknow ledgement ) segment s wi ll bedefeated by the forw ard TC P ( t ransmission co nt rol pro tocol ) segment s in the competi tion o f wi reless shared channel in IEEE 802. 11-based Ad hoc netw orks.Thus spurious TCP ret ransmi ssio n timeo uts w ill happen periodically. The analysis under static topo log y prov es that sui table link-lay er retransmissio n limit , e. g. 5,can g et optimal TC P performa nce. The o ptimum ret ra nsmi ssio n limi t i s related to the t raffic load added in the netw ork. The simula tion under dynamic to po logy show s that di fferent moving speed o f no des w on 't bring additio nal requi rement s on link-layer ret ransmission for higher TCP throug hput.

Key words: wi reless Ad ho c netw orks, medium access cont rol, t ransmission cont rol pro tocol