A fast serial Viterbi decoder ASIC for CDMA cellular base station

A fast serial Viterbi decoder (FSVD) ASIC for a base station channel card in IS-95 direct sequence-code division multiple access (DS-CDMA) has been developed using 0.8 /spl mu/m CMOS technology of Samsung. To reduce the decoding time and store path metrics, four add-compare-select (ACS) pairs with several internal SRAMs and one external 6 K byte SRAM are used, respectively. Decoding depth of FSVD is variable to get the better coding gain. It is shown that the proposed scheme can reduce decoding time considerably more than other schemes.