CDMA (code division multiple access) is one type of multiple access system used in radio communication. Other multiple access methods include TDMA and FDMA. WCDMA (wideband code division multiple access) is the main air interface used for third-generation mobile communication systems and is characterized by a wider band than CDMA. This volume covers the theoretical principles and standards of WCDMA. It begins with a general overview and then proceeds to more advanced material, providing a road map for the reader.