The radio frequency is a limited natural resource and getting enabled day by day due to growing demand of the wireless communication applications. To operate on a specific frequency band, license are needed. The use of radio spectrum in each country is governed by the corresponding government agencies. In conventional technique each user is assigned a license to operate in a certain frequency band. Most of the time spectrum remains unused. The allocated spectrum is not utilized properly; it varies with time, frequency and geographical locations. Thus to overcome the spectrum scarcity and...

Multirate techniques are commonly used in audio and video processing, communications systems, and transform analysis. In most applications multirate systems are used to improve the performance, or for increased computational efficiency. OFDM is a very attractive technique for wireless communication due to its spectrum efficiency and channel robustness. The major drawbacks of OFDM system are high peak-to-average power ratio (PAPR) and inter-carrier interference (ICI). In this book, several important aspects are described as well as a mathematical analysis is provided, including the...