A PN-acquisition ASIC for wireless CDMA systems

CDMA spread-spectrum systems require PN-acquisition to synchronize the transmitted signal at the receiver. Fast acquisition minimizes the amount of synchronization overhead required in the communication link for maximum system throughput. Yet, the fast acquisition should be done with low energy for portable applications. Conventional acquisition techniques using matched filters or serial correlators alone provide either fast pseudo-noise (PN) acquisition for CDMA or low power dissipation but not both. This paper presents an ASIC which implements a hybrid PN acquisition architecture that achieves both fast acquisition and up to 50% reduction in energy dissipation compared to conventional techniques. This ASIC has been fabricated using 0.5-μm CMOS technology with an area of 23 mm. It operates at 20 MHz with a 3.3 V supply and dissipates 50 mW per acquisition, or less than 1.5 mW per 50 byte packet