Inter-frame interleaved Bi-SOVA alogrithm for Underwater Acoustic Communication

For divergence of the adaptive DFE leading to loss of data frames and affecting the performance of Turbo decoding in harsh UAC (Underwater Acoustic Communication) channel, inter-frame interleaved Bi-SOVA decoding algorithm was proposed. Inter-frame interleaved Bi-SOVA algorithm encodes and decodes the whole data packet (28 frames) to correct the lost frames, since it can distribute error bits randomly. For inter-frame interleaved Bi-SOVA decoding algorithm leading to large data storage and intolerable decoding delay, sliding window decoding technology and the golden prime interleaver are adopted to optimize data storage, meanwhile DMA technology of ADSP-21160 is applied to optimize decoding delay. According to the result of practical experiment, under the same size of data packet, inter-frame interleaved Bi-SOVA, compared to classical Bi-SOVA, doesn´t increase data storage and decoding delay, meanwhile improve the decoding performance greatly. And it will correct 20% error frames under the best conditions.