Design and Analysis of Unequal Error Protection Rateless Spinal Codes

In this paper, we propose and analyze an unequal error protection (UEP) rateless spinal code, which can provide UEP and unequal recovery time properties. The proposed UEP spinal codes achieve UEP by the permutation of different priority levels and the setup of different segment sizes for different priority levels. In addition, an unequal length transmission scheme to improve the transmission rate is proposed, where the number of transmitted symbols in each pass varies. Moreover, we analyze the finite-length performance of the proposed UEP spinal code, which enables us to provide the upper bound of average error probability for each priority level under maximum likelihood decoding. Based on this finite-length result, we discuss the design of UEP spinal code, which is flexible and efficient. Furthermore, the asymptotic performance analysis shows that the proposed UEP spinal code with a practical decoder can achieve the capacities of both binary symmetric channel and additive white Gaussian noise channel. Simulation results verify our analysis.