Analytical Derivation of Multi-Variate Bit-Level EXIT Functions for Multilevel Codes

In this paper we analytically derive the Multi-variate Bit-Level Extrinsic Information Transfer (MV-BL-EXIT) function for a particular level of multilevel codes. The Binary Symmetric Channel (BSC) and Binary Erasure Channel (BEC) are considered for the derivation. The use of combined information is proposed to simplify the convergence analysis of multilevel codes. Bounds for the MV-BL-EXIT functions are also analyzed.