As wireless broadband technology has become very popular, the introduction of Worldwide Interoperability for Microwave Access (WiMAX) based on IEEE 802.16 standard has increased the demand for wireless broadband access in the fixed and the mobile devices. This development makes wireless security a very serious concern. Even though the Advanced Encryption Standard (AES) has been popularly used for protection in WiMAX applications, still WiMAX is exposed to various classes of wireless attack, such as interception, fabrication, modification, and reply attacks. The complexity of AES also produces high power consumption, long processing time, and large memory. Hence, an alternative cryptography algorithm that has a lower power consumption, faster and smaller memory, is studied to replace the existing AES. A Software Defined Radio (SDR) is proposed as a different way of proving the performance of the cryptography algorithm in real environments because it can be reprogrammed, which leads to design cost and time reductions.
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WiMAX is used for variety of purposes including, but not limited to, fixed last-mile broadband access, long-range wireless backhaul, and access layer technology for mobile wireless subscribers operating on telecommunications networks (Scarfone, et al., 2010). The WiMAX Forum has estimated that new WiMAX equipment will be capable of sending 40 Mbps data over 10 km in a Line-Of-Sight (LOS) fixed environment (Khan & Zaman, 2009). Therefore, WiMAX technology continues to adapt to market demands and provide enhanced user mobility. IEEE 802.16e-2005 was an amendment that enabled mobile WiMAX. This standard was built on Orthogonal Frequency Division Multiple Access (OFDMA). Most countries have allocated the bands for the wireless access between 3.4 and 3.6 GHz but the United States, Mexico, Brazil, and some Southeast Asian nations, have chosen instead the bands between 2.5 and 2.7 GHz (Ahson & Ilyas, 2008).
The mobile WiMAX system also has more enhanced security features than the existing IEEE 802.16-2004-based WiMAX network system. However, the mobile WiMAX system, which uses Advanced Encryption Standard (AES) scheme (Airspan, 2007; Yuksel, 2007), is still not able to guarantee the reliability of the whole mobile WiMAX systems and network architecture (Joseph, 2011). In this short period of their existence, various weaknesses have emerged. Some of the possible threats are similar to the ones that WiFi faced: this observation stresses on the importance of the WiFi threat analysis and the prevention measures that can be taken for WiMAX (Trimintzios & Georgiou, 2010). WiMAX has security vulnerabilities in both Physical (PHY) and Medium Access Control (MAC) layer, exposing to various classes of wireless attack including interception, fabrication, modification, and reply attacks (Jha & Dalal, 2010).