Wireless Network Security in Real-Time Applications

In this article a study of a wireless network system for agricultural facilities has been carried out. The proposed system consists of standard 802.11 hardware and Linux OS, which support application-level protocol of special usage case. Such protocol is developed right now in STRATOS project and therefore a test of such system real time response is needed. This research extends previously made tests with comparison of wired and wireless infrastructure and in particular discovers system working parameters with regard of encryption in wireless networks. For such tests systems analogue design was implemented in custom made application and testing was done in laboratory conditions. As a platform of choice Linux 2.6.33.7.2 kernel with RT preempt patches was chosen as it is heading for inclusion in mainline kernel tree. Experiments revealed the potential for real-time system operating limits and dependence of these limits on the wireless network encryption. The existing 802.11b standard equipment and a modern Linux kernel with real time patches give a combination that can provide real-time applications with the required 50-millisecond round trip time for both encrypted and unencrypted mode. Future testing can be extended with regard of external influences, for example, by performing field tests. Also there can be gains in usage of coordinated wireless infrastructure in point coordination function mode. This research also shows that by using the latest 802.11g or 802.11n standard hardware, the system will comply with given time limits with an even larger margin because measured packet processing time at systems is low enough (most of the time is spent in data reception and forwarding in physical environment). Test results show that the proposed system architecture is a promising solution for low latency communication in both industrial and mobile applications.