The failure of CSMA in emerging wireless network scenarios

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding


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.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Electrical Engineering, Electronic Engineering, Information Engineering


  • IEEE 802.11 Standards Multiaccess communication Propagation delay Protocols Throughput Wireless LAN Wireless communication
Original languageEnglish
Title of host publication[Host publication title missing]
Number of pages4
Publication statusPublished - 2014
Publication categoryResearch
EventWireless Days (WD), 2014 IFIP - Rio de Janeiro, Brazil
Duration: 2014 Nov 12 → …


ConferenceWireless Days (WD), 2014 IFIP
CityRio de Janeiro
Period2014/11/12 → …

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