Emerging demands for high data rate multimedia based services and high spectral efficiency are the key drives for the continued technology evolution in wireless communications. Recently, several advancements have been introduced for 3G wireless communication systems to further enhance the data rate and the system performance (e.g., high speed downlink packet access (HSDPA) in wideband code division multiple access (WCDMA) systems, 1x evolution-data and voice (1xEV-DV) for cdma2000 systems). However, due to the proliferation of wireless multimedia applications and services such as video teleconferencing, network gaming, and highquality audio/video streaming, it is apparent that 3G wireless systems will be unable to comply with this ever increasing demand for broadband wireless services.