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This paper presents the history-based scheduling (HBS) protocol for collision-free channel access in ad hoc networks. In HBS, the channel is scheduled based on the history of activity of each node in order to attain higher channel utilization than traditional distributed scheduling schemes based on node activation. Conflict-free access to the channel is determined at each node based on a priority list of the nodes within two hops of each node that takes into account the activity history of each node. To keep the activity history of each node synchronized, a node that is assigned the channel and has no data packet to transmit simply transmits a "nothing-to-transmit" (NT) packet in that time slot. In this way, the exchange of the signal packet should be reduced. The throughput and delay characteristics of HBS are compared analytically and by simulation with those of CSMA/CA and the node activation multiple access (NAMA) protocol.