Systems delay characteristics of a busy-tone protocol in CCA modified, long range IEEE 802.11 networks

This paper discusses the delay characteristics and packet drop ratio performance of Busy Tone Multiple Access Protocol (BTMAP) for distances up to 48Km in IEEE 802.11 networks. The impact of the Contention Window (CW) is discussed. We note that a larger CW will increase the mean packet delay but decrease the packet drop ratio. Long range also significantly degrades the delay and packet drop ratio performance of the BTMAP, however, with the same number of users, a larger cell will cause higher drop ratio but shorter delay. This indicates that larger distances increasingly corrupt packets and are problematic to long range communications. At extremely long range (48Km), by choosing a user number less than CW, it is still possible to control the mean packet delay to under 100ms which is acceptable for VoIP networks, but the packet drop ratio is remains high due to transmission delay.