On the Performance of Tanner Graph Based and Viterbi Decoding for Erasure Recovery

We address the utilization of short erasure correcting codes to recover the erased data in opportunistic spectrum access (OSA) due to collisions among multiple users. The main application of using short codes over long codes is to avoid long delays in the network. Various erasure correcting codes are envisioned and their decoding methods are compared to analyze the erasure recovery capability. The decoding performance of Tanner graph based approach is compared with the Exhaustive search based approach that achieves the maximum achievable performance. With the use of extended H matrix there is a huge gain in erasure recovery of lost data and this performance is comparable with Exhaustive search. The Viterbi decoding for erasure recovery is also described with examples and the three techniques are compared to analyze the decoding complexity.