The failure of CSMA in emerging wireless network scenarios

Author

Fitzgerald, Emma ; Landfeldt, Bjorn

Author_Institution

Sch. of Electr. & Inf. Technol., Lund Univ., Lund, Sweden

fYear

2014

fDate

12-14 Nov. 2014

Firstpage

1

Lastpage

4

Abstract

The current family of 802.11 protocols are based on the Carrier Sense Multiple Access (CSMA) mechanism which is a simple and robust means of sharing a channel. However, two current trends in wireless networks point towards a situation where CSMA fails to perform better than pure random access solutions such as ALOHA. The first trend is the ever increasing raw data rate in each generation of 802.11 which is set to continue with the current 802.11ax standardisation. The second is the move towards smaller frames as end users increasingly use mobile devices instead of desktop computers. We show that as the ratio of propagation delay to packet transmission time increases, the performance of CSMA degrades correspondingly, to the point where ALOHA outperforms CSMA.

Keywords

access protocols; carrier sense multiple access; radiowave propagation; wireless LAN; wireless channels; 802.11 protocols; 802.11ax standardisation; ALOHA; CSMA failure; carrier sense multiple access mechanism; channel sharing; packet transmission time; propagation delay ratio; wireless LAN; wireless networks point; IEEE 802.11 Standards; Multiaccess communication; Propagation delay; Protocols; Throughput; Wireless LAN; Wireless communication; 802.11; 802.11ax; CSMA; MAC; wireless LAN;

fLanguage

English

Publisher

ieee

Conference_Titel

Wireless Days (WD), 2014 IFIP

Conference_Location

Rio de Janeiro

Type

conf

DOI

10.1109/WD.2014.7020830

Filename

7020830