A RAKE-DFSE equalizer for the UMTS downlink

The UMTS radio interface based on CDMA, has been designed to offer a wide range of data rates using variable spreading factor. It is ongoing standardization effort to include a high data rate packet mode in the downlink direction. This new mode is called high speed downlink packet access (HS-DPA) and is characterized by the giving up of closed loop power control, link adaptation using variable constellations (QPSK, MAQ16,MAQ64), and low spreading factor. The proposed receiver is particularly adapted to HSDPA mode has it gives close to optimal performance even in the case of high modulation order and low spreading factor while keeping a reasonable complexity.