Group Allocation Multiple Access in Single-Channel Wireless LANs
Andrew Muir, Jose Joaquin Garcia-Luna-Aceves · 1998
The Group Allocation Multiple Access (GAMA) protocol for scheduling variable-length packet transmissions in a single-hop packet-radio network is specified and analyzed. By maintaining a dynamically-sized cycle that changes in length depending on the amount of network traffic, GAMA is able to provide the advantages of both TDMA and CSMA. Each cycle contains a contention period and a group-transmission period; a station with data to send competes for the right to be added to the transmission group by successfully completing an RTS/CTS message exchange during the contention period. Once a station is a member of the transmission group, it is able to transmit a collision-free data packet during each cycle. As long as a station has data to send, it maintains its position in the group. This can be viewed as either allowing stations to “share the floor ” in an organized manner, or as establishing frames that are not synchronized on a slot-basis and vary their length dynamically based on demand. The throughput and average delay of GAMA are presented and analyzed; to validate our analysis, the results of both models are compared to the throughput and delay produced by a simulation of GAMA.