y Insights To conclude, the chapter provided the highlights of the WiMAX standard including its PHY and MAC layers. It also described different types of Smart Antennas including receive and transmit diversity and MIMO. The results of field testing that we conducted and results that are publicly available were also provided in the chapter. WiMAX network reference model and integration with WiFi and use of femtocells were also discussed. We also proposed a solution for the delivery of end to end QoS in WiMAX and WiFi hybrid networks. The details of WiMAX certification process, forecast and WiMAX roadmap were also discussed. The five key challenges that need to be looked into in order to make Mobile WiMAX and 802.16m a strong competitor to EV-DO, HSPA and LTE and to future LTE-Advanced respectively are: Next Generation Mobile Communications Ecosystem Acceptance of Mobile WiMAX from additional tier-1 operators. Faster and thorough Certification Process. Better availability of WiMAX femtocells. Better availability of low cost fixed and mobile WiMAX devices. Strong Ecosystem for Mobile WiMAX and 802.16m. References 1. Asif, S.Z. (2007) Wireless Communications Evolution to 3G and Beyond, Artech House, Inc., Norwood, MA. 2. IEEE Std 802.16-2004 (2004) IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed Broadband Wireless Access Systems, IEEE, October. 3. IEEE Std 802.16e (IEEE Std 802.16e-2005 and IEEE Std 802.16-2004/Cor1-2005) (2006) IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems, Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1, IEEE, February. 4. IEEE Std 802.16-2009 (2009) IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Broadband Wireless Access Systems, IEEE, May. 5. WiMAX Forum (2006) Mobile WiMAX - Part I: A Technical Overview and Performance Evaluation, August. 6. Etemad, K. 