A simple modification for the drastic improvement of MACA in large propagation delay situation

The idea of the option of IEEE 802.11 standard (for wireless LANs) to exchange RTS (Request-To-Send) and CTS (Clear-To-Send) short packets is based on the MACA (a media access control protocol for packet radio network) proposed by Phil Kern in 1990. We previously showed the result that in the case of large propagation delay time and small RTS recognition time, there is very large difference between upper and lower bounds of the throughput of MACA. This paper shows that very simple modification of the state transition can drastically improve the lower bounds of performance of MACA in the above case nearly up to the upper bounds of it.