The tremendous growth of Information and Communication Technology (ICT) has unknowingly influenced our lifestyle. We are making more phone calls, exchanging more emails and spending more time on the World Wide Web than we did a decade ago. The nature of information content is also evolving. High definition video streaming, online shopping, online banking and content sharing libraries are some of the new paradigms that have replaced the simple web applications of early days. In such circumstances, the objectives for future networks are more challenging. This book focuses on the IEEE 802.11 MAC and identifies several challenges that require further research. The IEEE 802.11 standard for local area networks, specifically the IEEE 802.11e, is discussed in a tutorial style. The primary focus is on rate-adaptation schemes for multi-rate WLANs stations and design of QoS enabled routing protocol by incorporating information from the IEEE 802.11e compliant MAC. The book serves as a valuable reference for researchers, professionals and students who would like to gain a more formal understanding of Cross-layer optimization techniques and specifically the IEEE 802.11 standard.