Throughput Dependence on SNR in IEEE802.11 WLAN Systems

IEEE 802.11 WLANs

The first IEEE802.11 WLAN standard which supported data rates up to 2 Mbps was released in 1997 (Obaidat et al, 2008). The standard defined both the physical layer and the medium access control (MAC) layer. Other IEEE802.11standards such as IEEE802.11a, IEEE802.11b, IEEE802.11g, IEE802.11n, (with higher data rates), IEEE802.11e (for better quality of service support) and IEEE802.11i (for security), IEEE802.11ac, IEEE802.11ax have been developed since then.

At the physical layer IEEE 802.11n can provide data rates up to 54Mbps in a 20MHz band with at least 100Mbps at the MAC data services access point using only mandatory features specified in the standard (Metreaud, 2006). Newer standards such as IEEE802.11ac and IEEE802.11ax offer up to 1,300Mbps and 2Gbps respectively (Jamie, 2015). The popularity of the IEEE802.11 “family of standards” has continued to increase due to their convenience and the reduction in prices of their hardware. The discussion in this chapter is however limited to the base standards because available in literature are throughput models which predict throughput directly from observed SNR only for these base standards.

Radio frequency (RF) based WLANs (which are more common than the IR-based ones) operate in the International Scientific and Medical (ISM) band which does not require any licensing from the US FCC (Obaidat et al., 2008). They use RF signals which can pass through obstacles to transmit and receive data through the air without any connecting cables thus providing freedom and flexibility unmatched by Wired LAN.