Abstract: | A memory and driving clock efficient design scheme to achieve WCDMA high-speed channel decoder on a single XILINX' XVC1000E FPGA chip is presented. Using a modified MAP algorithm, say parallel Sliding Window logarithmic Maximum A Posterior (PSW-log-MAP), the on-chip turbo decoder can decode an information bit by only an average of two clocks per iteration. On the other hand, a high-parallel pipeline Viterbi algorithm is adopted to realize the 256-state convolutional code decoding. The final decoder with an 8×chip-clock (30.72MHz) driving can concurrently process a data rate up to 2.5Mbps of turbo coded sequences and a data rate over 400kbps of convolutional codes. There is no extern memory needed. Test results show that the decoding performance is only 0.2~0.3dB or less lost comparing to float simulation. |