Reverse link demodulator ASIC for CDMA cellular system

In this paper, we describe the design and implementation of a code division multiple access (CDMA) base station demodulator (CBD) ASIC for the use in the IS95-based CDMA mobile communication system. We propose a novel design method for the noncoherent OQPSK PN correlator, fast Hadamard transformer (FHT), lock detector, and time tracking loop, which are the main functional blocks of the demodulator. We also present the implementation environment for the design and verification of the demodulator ASIC. The chip has been designed using a cell-based design methodology and fabricated by double-metal 0.8-μm CMOS technology. The die of the chip measures 8.1×8.3 mm and it contains approximately 75000 logic gates and 3000 bits of static RAM