Encryption vs. performance of infrastructure IEEE 802.11 WLANs

One of the reasons that many IEEE 802.11 WLAN infrastructures do not utilize signal encryption may be related to the general perception that encryption largely degrades performance of the system. Especially, there have been several recent research studies suggesting that encryption could noticeably degrade performance of WLAN systems by as much as 20%. Here, we note that the 2.4-GHz frequency spectrum used in the WLAN systems is unlicensed and shared by various kinds of wireless devices and applications, and essentially the high interference in this frequency band may greatly affect the experiment results. Thus, it is worthwhile to reinvestigate and verify whether encryption in WLANs actually causes that much performance degradation. In essence, encryption should only have minimal impact because the amount of overhead inserted by the encryption algorithms is normally less than 1% of the total payload. In this work, we reinvestigate the issue of encryption vs. performance of infrastructure IEEE 802.11 WLANs. A very quiet test site is selected in order to obtain reliable test results. The experiment results in this work demonstrate that the impact of encryption on the throughput performance of an infrastructure IEEE 802.11 WLAN system is negligible.