Bandwidth reduction of extrinsic information exchange in turbo decoding

Besides computations and decoding delay, iterations in turbo decoding imply intensive and random extrinsic information exchange between component decoders. This high data exchange rate needs huge communication and routing resources to support the required bandwidth. Proposed is a novel symbol-based criterion to reduce the extrinsic information bandwidth in turbo decoding. The proposed criterion measures each symbol's contribution to the convergence of the iterative process and inhibits unnecessary extrinsic information exchange according to an appropriate threshold. Simulation results demonstrate a 20-25% mean extrinsic information exchange rate reduction with negligible error-rate degradation. This significant bandwidth reduction can directly alleviate communication and routing architecture.