Sector-based RTS/CTS access scheme for high density WLAN sensor networks

Wireless LANs (WLANs) are increasingly becoming popular. Indeed the trend is to use WLAN interfaces in many instruments and devices. This increasing number of user terminals in WLANs has thrown new access issues. This motivates the redesign of the current wireless media access schemes. We analyze the performance of such high density WLANs and discuss the limitations of the IEEE 802.11 Distributed Coordination Function (DCF) when request to send/clear to send (RTS/CTS) is used as a media access management scheme. Our numerical evaluation and simulation studies exhibit a significant performance reduction when the RTS/CTS access scheme is used due to an increased number of RTS frame collisions. This happens when the density of WLANs starts increasing. We thus propose a novel sector-based RTS/CTS scheme that allows a significant throughput improvement for massive access scenarios in high density WLANs by utilizing a spatially orthogonal access scheme. This type of access scheme would be particularly beneficial in machine-to-machine (M2M) communication networks and for internet of things (IoT) applications.