Theoretical Performance Evaluation of a Concatenated Rateless-FEC Coding Scheme

This paper presents the theoretical evaluation of the reliability and spectral efficiency performances provided by a two-level coding scheme that concatenates a rateless erasure code and a convolutional code, over Rayleigh block-faded channels. It studies the message non-recovery probability (p_NR) and the spectral efficiency provided by such a coding scheme versus the average SNR in terms of the rateless and channel codes' parameters. The performance evaluation is performed both "downwards", i.e. by establishing the minimum SNR value for which a target non-recovery probability is ensured, and "upwards", i.e. by computing the non-recovery probability and spectral efficiency for a given average SNR value. The numerical results presented show that the concatenated rateless-channel codes provide significant coding gain, compared to pure channel-coding of the same rate, in block-fading channels and their performance gets better with the increase of the message length.