Analog Turbo-Networks in VLSI: the Next Step in Turbo Decoding and Equalization

Since turbo decoders are a step towards analog because they use continuous values in soft-in/soft-out decoders the next step is to go fully analog by exchanging extrinsic information in continuous time (flooding). The component decoders are realized in analog VLSI (a simple chip exits in 0.25microns BiCMOS technology) to perform trellis or message passing decoding in continuous time connected by an interleaver network. Measurement and simulation results for Turbo receivers with Hamming-, DECPSK-, multi-path-channel-, codes show that comparable performance of the analog turbo networks is feasible at much higher speed, lower size and power consumption.