The demand for broadband services is growing exponentially. Mobile users are demanding higher data rates and higher-quality mobile communication services. The Generation Mobile Communication System (third generation, 3G) is an outstanding success. The conflict of rapidly growing users and limited bandwidth resources requires that the spectrum efficiency of mobile communication systems be improved by adopting some advanced technologies. It has been proved, in both theory and practice, that some novel key technologies, such as MIMO (multipleinput, multiple-output) and OFDM (orthogonal frequency-division multiplexing), improve the performance of current mobile communication systems. Since the first deployment of the commercial wireless systems, wireless mobile networks have evolved from the first-generation analog networks to the second-generation (2G) digital networks. Along with the rapid growth of the wireless voice service, 3G wireless mobile networks are deployed to offer more efficient circuit-switched services that utilize many advanced techniques to more than double the spectral efficiency of the 2G systems.