Reservation ALOHA. Reservation ALOHA, or R-ALOHA, is a channel access method for wireless (or other shared channel) transmission that allows uncoordinated users to share a common transmission resource. ... Additionally, Reservation ALOHA simply stops sending data once the station has completed its transmission.

In the reserved mode the time axis is divided into fixed-length frames. Each frame consists of M+1 equal-length slots of which the first M slots are used for message transmission (message slots) and the last slot is subdivided into R short reservation subslots used for reservation. A sending user that has been granted a reservation sends its packets in successive message slots, skipping over the reservation subslots when they are encountered. When there are no reservations taking place, the system returns to the unreserved mode.
A number of cases of slotted Aloha protocols for high-speed optical fiber local area networks (LANs) are presented and analyzed. The results are compared to the cases of Slotted Aloha/Aloha schemes presented by I.M.I. Habab et al., (1987) and N. Mehravori (1990). The proposed schemes were found to offer better throughput and delay characteristics. These cases are also compared with Aloha/N-server and CSMA/N-server protocols presented by Habab and Mehravori. Some of the considered protocols offer better throughput when the data packet lengths are small. Two cases of reservation Aloha protocols are presented and analyzed.

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